Operable Unit 7-13/14 In Situ Grouting Treatability Study Work Plan · 2015. 12. 1. · 1-1....

DOE/ID-10690September 1999

U.S. Department of EnergyIdaho Operations Office

Operable Unit 7-13/14In Situ Grouting Treatability Study Work Plan

I I•1 MUM I I Ni IXIMI rzIhAIXnKMFNInI.IABONATORY

DOVID-10690


Published September 1999

Prepared for theU.S. Department of EnergyIdaho Operations Office

ABSTRACT

In situ grouting has been demonstrated for the stabilization of transitionmetals. The purpose of this treatability study is to address remaining questionsrelative to the use of in situ grouting to stabilize the variety of heterogeneouswastes and intermixed soils found at the Subsurface Disposal Area of the IdahoNational Engineering and Environmental Laboratory. Data will be collected toprovide information for evaluation of Comprehensive Environmental Response,Compensation, and Liability Act criteria as part of the feasibility study for theOperable Unit 7-13/14. Two different potential uses of in situ grouting arestabilization for long-term disposal and confinement during retrieval.Treatability study uncertainties are associated with this as a selected remedy.Critical objectives that will be addressed are (a) whether grouting for long-termdisposal or confinement during retrieval is administratively feasible at theSubsurface Disposal Area, (b) the durability of the encapsulated and stabilizedwaste form, (c) field implementability of grout emplacement, (d) the hydraulicproperties of the encapsulated waste, (e) the physical and chemical groutproperties to identify an appropriate stabilization material, and (f) the ability ofgrout to control contaminant solubility. Noncritical objectives that will beaddressed for long-term disposal are the volume, type, and expected dispositionroutes of secondary waste; the distribution patterns of rare-earth tracers, andnitrate salts in grouted waste; and time, equipment, and labor requirements formobilization, demobilization, and operations. Administrative data from thelong-term disposal tests will also address questions applicable to confinementduring retrieval. Additional objectives to be addressed for confinement duringretrieval in the study are (a) quantify the level of dust control for evaluation asthe primary confinement, (b) whether a neutron absorption material can besuccessfully and homogeneously distributed through the grout, and (c) whateffects the grout will have on Btu content in the waste.

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CONTENTS

ABSTRACT

ACRONYMS

1. PROJECT DESCRIPTION

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1-1

1.1 Long-Term Disposal 1-2

1.1.1 LTD Evaluation Strategy 1-3

1.2 Confinement During Retrieval 1-4

1.3 SDA Background 1-6

1.3.1 Location 1-61.3.2 Review of SDA Geology 1-61.3.3 Historical Waste Disposal Operations from 1952 to 1985 1-81.3.4 Contemporary Operations, 1986 to the Present 1-101.3.5 Contaminants of Potential Concern 1-111.3.6 Double Confinement Requirement for Excavated Waste 1-11

1.4 In Situ Grout Background 1-14

1.4.1 In Situ Grout Method 1-141.4.2 In Situ Grout Variables 1-14

1.5 Preliminary Regulatory Requirements 1-16

1.6 In Situ Grouting Target Inventory 1-17

2. REMEDIAL TECHNOLOGY DESCRIPTION 2-1

2.1 Previous INEEL Stabilization Studies 2-1

2.1.1 Innovative Grout/Retrieval Demonstration 2-12.1.2 Subsurface Stabilization of Simulated Transuranic Pits and

Trenches Demonstration 2-12.1.3 Innovative Subsurface Stabilization Project 2-22.1.4 Acid Pit Stabilization Treatability Study 2-3

2.2 Description of the Jet-Grout Technology 2-4

2.2.1 Description of Contamination Control Measures 2-5

2.3 Grout Test Material Selection 2-6

2.3.1 Grout Material Screening Process 2-6

2.4 Verification Technology Description 2-7

3. TEST OBJECTIVES 3-1

3.1 In Situ Grouting for Long-Term Disposal 3-1

3.1.1 Critical Test Objectives 3-13.1.2 Noncritical Objectives 3-5


3.2.1 Unique Critical Objectives 3-73.2.2 Unique Noncritical Objectives for In Situ Grouting Confinement

During Retrieval 3-8

4. EVALUATION OF TECHNOLOGY 4-1

4.1 In Situ Grouting for Long-Term D sposal 4-1

4.1.1 Bench Testing 4-24.1.2 Implementability Testing 4-84.1.3 Field Testing 4-10

4.2 In Situ Grouting for Confinement During Retrieval 4-29

4.2.1 Bench Testing 4-294.2.2 Implementability Testing 4-314.2.3 Field Testing 4-324.2.4 Cost Information 4-38

5. EQUIPMENT AND MATERIALS 5-1

5.1 Required Equipment and Materials Long-Term Disposal 5-1

5.1.1 Required Equipment and Materials for Bench Tests 5-15.1.2 Required Equipment and Materials for Implementability Testing 5-25.1.3 Required Equipment and Materials for Field Tests 5-3

5.2 Required Equipment and Materials for Confinement During Retrieval 5-5

5.2.1 Required Equipment and Materials for Bench Tests 5-55.2.2 Required Equipment and Materials for Implementability Tests 5-65.2.3 Required Equipment and Materials for Field Testing 5-6

6. SAMPLING AND ANALYSIS 6-1

6.1 Sampling Objectives 6-1

6.2 In Situ Grouting Long-Term Disposal 6-2

6.2.1 Sampling and Analysis for Bench Testing 6-26.2.2 Sampling and Analysis for Implementability Testing 6-36.2.3 Sampling and Analysis for Field Testing 6-3

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6.3.1 Sampling and Analyses for Bench Testing 6-66.3.2 Sampling and Analyses for Implementability Testing 6-66.3.3 Sampling and Analyses for Field Testing 6-6

7. DATA MANAGEMENT 7-1

8. DATA ANALYSIS AND INTERPRETATION 8-1

8.1 Data Reduction for All Tests 8-1

8.2 Data Validation for All Tests 8-1

8.3 Procedures for Assessing Data 8-2

8.3.1 Notation 8-28.3.2 Estimation of the Variance of the Measurement Process (02„,cas) 8-28.3.3 Estimation of Bias 8-2

8.4 Data Analysis and Interpretation to Support Long-Term Disposal 8-3

8.4.1 Data Analysis and Interpretation for Bench Tests 8-38.4.2 Data Analysis and Interpretation for Implementability Testing 8-48.4.3 Data Analysis and Interpretation for Field Test 8-5

8.5 Data Analysis and Interpretation of Bench Tests to Support ConfinementDuring Retrieval 8-9

8.5.1 Data Analysis and Interpretation for Bench Testing 8-98.5.2 Data Analysis and Interpretation for Implementability Testing for

Confinement During Retrieval Option 8-108.5.3 Data Analysis and Interpretation for the Tests to Support the

Confinement During Retrieval Option 8-10

9. QUALITY ASSURANCE 9-1

10. HEALTH AND SAFETY 10-1

11. RESIDUALS MANAGEMENT 11-1

11.1 Bench Testing 11-1

11.2 Implementability and Field Testing 11-2

12. COMMUNITY RELATIONS 12-1

13. REPORTS 13-1

13.1 Weeldy Reports 13-1

13.2 Interim Support Documents 13-1

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13.3 Final Treatability Study Report 13-1

14. SCHEDULE 14-1

15. MANAGEMENT AND STAFFING 15-1

16. BUDGET 16-1

17. REFERENCES 17- I

Appendix A—Detailed Strategy for Testing the Effectiveness and Durabilityof the In Situ Grout, Long-Term Disposal Option A-1

Appendix B—In Situ Grouting Target Inventory B-1

Appendix C—Preliminary Criticality Safety Concerns During In Situ Remediation C-1

FIGURES

1-1. Data flow/usage. 1-2

1-2. Modified well-drilling apparatus used for jet grouting 1-5

1-3. RWMC including SDA and Cold Test Pit 1-7

2-1. Jet-grouting apparatus 2-5

4-1. Overall schematic of in situ grout technology evaluation testing. 4-1

4-2. Design features of long-term disposal pit. 4-13

4-3. Plan view of long-term disposal pit (special waste orientation) with locationof proposed well locations. 4-14

4-4. Basic thrust block module design. 4-15

4-5. Schematic of basic jet-grouting contamination control measures. 4-17

4-6. HEPA vacuum system installed on drill. 4-18

4-7. Features of contamination control system. 4-19

4-8. Catch can installed at the bottom of the catch cup and drip pan showinggrout droppings. 4-20

4-9. Schematic of cleanout process 4-22

4-10. Design features of in situ grouting confinement during retrieval pit. 4-33

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TABLES

1-1. Interim risk assessment (Becker et al. 1998) simulated peak risks and hazardindices for the 1,000-year simulation period. 1-12

1-2. In situ grouting ARARs. 1-18

4-1. In situ grouting for long-term disposal bench physical and chemicaltesting requirements 4-5

4-2. Grout performance requirements and acceptance criteria.a 4-8

4-3. Volume fractions of buried TRU waste (SDA-wide). 4-11

4-4. Pit 6 waste/soil volumes. 4-11

4-5. Simulated waste packages for the disposal pit 4-11

4.6. Testing methods for monolith samples 4-28

4-7. Simulated waste packages for the retrieval pit. 4-33

6-1. Test methods. 6-3

6-2. Testing requirements for monolith samples from the long-term disposal study 6-5

14-1. Working schedule for the in situ grouting treatability study. 14-1

16-1. Proposed budget for the in situ grouting treatability study. 16-1

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ACRONYMS

AEC Atomic Energy Commission

API American Petroleum Institute

ARAR applicable or relevant and appropriate requirement

ASTM American Society of Testing and Materials

CDR confinement during retrieval

CERCLA Comprehensive Environmental Response, Compensation, and Liability Act

CFR Code of Federal Regulations

DOE Department of Energy

DOE-ID Department of Energy-Idaho Operations Office

DOT Department of Transportation

ECL Environmental Chemistry Laboratory

EM-50 DOE Environmental Management Division, Office of Science and Technology

EPA Environmental Protection Agency

ER Environmental Restoration

HEPA high-efficiency particulate air

ICP inductively coupled plasma

ICP-MS inductively coupled plasma-mass spectrometry

IDAPA Idaho Air Pollution Act

IDHW Idaho Department of Health and Welfare

INEEL Idaho National Engineering and Environmental Laboratory

LLW low-level waste

LMITCO Lockheed Martin Idaho Technologies Company

LTD long-term in situ waste disposal

M&O management and operating

MCP management control procedure

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NESHAP National Emission Standards for Hazardous A r Pollutants

NPDES National Pollutant Discharge Elimination System

NRTS Nuclear Reactor Test Site

OU operable unit

PCE perchloroethylene (tetrachloroethylene)

PRD program requirements document

QC quality control

RCRA Resource Conservation and Recovery Act

RI/FS Remedial Investigation/Feasibility Study

RWMC Radioactive Waste Management Complex

SDA Subsurface Disposal Area

SMO Sample Management Office

SOP standard operating procedure

SPCC Spill Prevention Control and Countermeasures

TCA 1 ,1 ,1-trichloroethane

TCE trichloroethylene

TRU transuranic

TSA Transuranic Storage Area

TSCA Toxic Substances Control Act

VOC volatile organic compound

WAG waste area group

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1. PROJECT DESCRIPTION

This Treatability Study Work Plan, for Operable Unit (OU) 7-13/14, provides the strategy forconducting bench and field tests associated with in situ grouting of subsurface waste and contaminatedsoils as a remediation option for the Subsurface Disposal Area (SDA) at the Idaho National Engineeringand Environmental Laboratory (INEEL). The purpose of the work plan is to describe the work to beconducted in support of the primary treatability study objective, which is to provide sufficienteffectiveness, implementability, and cost data to evaluate the in situ grouting technologies as a buriedwaste treatment altemative for the OU 7-13/14 Remedial Investigation/Feasibility Study (RI/FS). Thiswork plan includes background information on the SDA, a description of the in situ grouting techniqueincluding past applications of the technology, an analysis of data factors needed to support the primaryobjective, and a description of the studies to be undertaken to address the data factors. The study willexplore two possible applications of the in situ grouting technology for application in the SDA:

• Long-term in situ waste disposal (LTD)

• Confinement during retrieval (CDR).

The first application, LTD, is to provide in-place stabilization of waste and soil, which will allowsafe long-term management of the materials (i.e., long-term disposal). The second application, CDR, isfor in-place stabilization of the waste to increase safety and efficiency during retrieval and ex situ wastemanagement (confinement during retrieval).

The SDA landfill is one of the waste area groups (WAGs) that falls under the jurisdiction of theComprehensive Environmental Response, Compensation, and Liability Act (CERCLA). Grouting of allor some portion of waste and disturbed soils in place is a treatment option identified in the OU 7-13/14Addendum to the Work Plan for the Remedial Investigation/Feasibility Study Work Plan Addendum(DOE-ID 1998). Full-scale research programs for both the long-term disposal and confinement duringretrieval applications of in situ grouting have been completed at the INEEL to aid in the development ofthe technology for eventual SDA application. These programs have resulted in a database ofimplementability and effectiveness information on in situ grouting. Results are described in theInnovative Grout/Retrieval Demonstration Final Report (Loomis and Thompson 1995a), InnovativeSubsurface Stabilization Project—Final Report (Loomis et al. 1995b), and Acid Pit Stabilization Projectconducted at the INEEL (Loomis et al. 1999). Examination of these data resulted in the identification ofseveral data gaps that formed the basis for the treatability study experimental design. This design will bediscussed further in succeeding sections.

This Treatability Study Work Plan provides the technical details for conducting testing, managedthrough a graded approach. The study will take place in three phases for each grout usage: bench,implementability, and field testing. The purpose of the bench tests is to down select grout materials andformulations that exhibit desired physical and chemical properties for jet grouting and treatment ofsurrogate waste matrices. This testing will ensure that the treatability study includes the breadth ofgrouting materials suitable for in situ jet grouting. Additionally, parallel testing will be conducted on tworelatively new vendor products Implementability testing of grouts will then be performed to obtain fieldinformation concerning optimal injection parameters and properties of the resulting monoliths. Then the

two most appropriate grouts (one for long-term disposal and one for confinement during retrieval) will befield tested in a simulated test pit designed to represent average conditions at the SDA. Decision pointsare structured into the treatability study to ensure that key issues are addressed satisfactorily beforeresources are committed to subsequent test phases. Figure 1-1 depicts various stages of data flow bothintemal and extemal to the treatability study. The study is designed to generate data from the bench,implementation, and field testing that will directly and indirectly support the feasibility study alternativeevaluation and ultimately the WAG-7 OU 7-13/14 Record of Decision. Specified data will be utilized asdirect inputs to the INEEL risk model for processing long-term effectiveness information. Risk modeliterations will also receive empirical data from treatability study efforts relative to contaminant solubilitychemistry and diffusivity to enhance processing. The model inputs combined with modifiedadministrative and cost information from the in situ vitrification treatability study and past in situ groutinghot testing will be addressed in the final technology report for consideration in the alternative evaluationstage of the feasibility study for the in situ grouting technology (reference Appendix A for a more detaileddiscussion of this strategy). Cost estimates will be based on current material and labor costs and willreflect operational efficiencies that would be realized in a production scenario versus a test mode. Thefollowing subsections identify main test objectives and associated experimental designs to fill data needsassociated with these technology application objectives.

1.1 Long-Term Disposal

The main test objective for the long-term disposal application of grout is to demonstrate a reductionin risk to human health and the environment by affecting contaminant migration from the SDA. Thisobjective will be supported by addressing five data needs in the test design:

1. Thrust Block Durability—As part of the contamination control system, the technologydeploys a solid platform or thrust block at ground surface. Following emplacement, theblock is left in place to act as a barrier to infiltration of surface water, similar to that of anengineered cap. Available industry literature and grout durability testing will be utilized todetermine a degradation rate for this structure. The data will be presented in the InterimReport for this study. These data will be used in the modeling effort to determine effects oncontaminant release rates, mobility, and future risks.

2. Physical Stability (subsidence control)—The grout mixture injected into buried waste willstabilize it by filling voids in the waste and preventing site subsidence and surface waterponding.

n Situ GroutingLTD Historical

Data

ChernicalPrinciples

Measured EffectivenessIn Situ Grouting WAG-7 OU-13/14LTD Treatability variables INEEL data RI/FS (Feasibility WAG-7 OU-13/14Study Data Risk Model Study Alternative ROD (End)

(Bench & Field) Evaluation)In Situ Grouting

Treatability Cost. implementation dataRI/FS In SituStudies (Start)

Vitrification Hot

In Situ Grouting CDRTreatability Study

Implementation & effectiveness data Test (AdministrativeCost Data)

GM99 0113(Bench & Field)

Figure 1-1. Data flow/usage.

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3. Regional Decrease in Hydraulic Conductivity—The injected grout incorporates the buriedwaste, creating a monolith with a very low permeability. An average hydraulic conductivitywill be measured for the treated waste seam. Results will be utilized in the modeling effort.

4. Monolith Chemical Buffering—Grout products were selected in part for testing due to theirpositive effects on waste component stabilization from immobilization by the chemicalbuffering. Oxidation-reduction potential (Eh) and the acid-base character (pH) ofgroundwater within the monolith are buffered by the grout to reduce solubility, thereforereducing mobility of some waste components. Buffering by the grout is expected to last1,000 to 10,000 years or more (Alcorn et al. 1990). Results will be utilized in the modelingeffort.

5. Monolith Durability—The life expectancy of the in situ grout material to provide protectionto human health and the environment will be determined through testing and empiricalderivations.

The test design commences with bench and implementability testing to provide data for theselection of a grout for testing in the field. These data will also serve as a baseline for verification ofsome field test results and be used for the risk model as part of the feasibility study alternative evaluations(see Figure 1-1). The jet-grouting implementability tests will be conducted in a field setting by the jet-grouting equipment suppliers to verify field application parameters for the chosen grouts and to evaluate

the stabilization properties. The field tests will then be conducted on a simulated buried-waste pitdesigned to approximate an average SDA site with respect to contents and configuration.

Field testing entails the application of grout material, injected at high pressure and velocity, to theburied waste site using a modified well-drilling apparatus as shown in Figure 1-2. The high velocity of

the injected grout will create a mixture of waste, soil, and grout and the filling of voids. Test objectiveswill be addressed with data obtained during field implementation and from posttest physical and chemicalanalysis performed on the monolith and associated samples.

Data from the field test will be used to:

• Verify application parameters (e.g., grout viscosity and density, curing time and temperature,etc.)

• Provide data for performance verification (e.g., postexcavation field observations for column

development and overlap, and laboratory measurements of physical characteristics of themonolith, etc.)

• Provide measurements of average hydraulic conductivity for the treated site

• Estimate the solubility state and potential release mechanism with an associated rate forindividual contaminants of primary concern.

1.1.1 LTD Evaluation Strategy

As previously discussed, Figure 1-1 depicts data flow from the LTD treatability study directly tothe feasibility study as well as to the IISEEL risk model whose output data are also used in the "feasibilitystudy alternative evaluation." The following discussion introduces the reader to the LTD evaluation

strategy that guided this test design.

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Treatability study resultant data types can be divided into two categories: implementation data andeffectiveness data. Implementation data provide information relative to operational aspects of the testsuch as evaluation of safety measures and procedures, contamination control, production times, costs, andmaterials, etc. These data will be supplied directly to the feasibility study alternative evaluation.Effectiveness data pertain to the projected long-term performance of the treated site and its ultimate effecton groundwater risk reduction. As depicted in Figure 1-1, this information, for the most part, will besupplied by the model that will utilize specific inputs from the treatability study to generate an accurateevaluation of the monolithic grout treatment of the waste. These model "inputs" allow for considerationof two forms of protection from the monolith: (a) control of site hydraulic properties to preclude surfacewater infiltration, and (b) chemical stabilization of contaminants from reactive grouts.

1.1.1.1 Control of Sfte Hydraulic Properties. Control of site hydraulic properties is theprimary line of defense provided by an in situ monolithic treatment process. Groundwater in a subsurfacewaste environment in most cases acts as the primary mechanisms for contaminant release and transport.Control of this influx allows for a chemically stable environment where waste products may reside forinfinite periods. For the purpose of this study, grout products were chosen for consideration that areeither chemically similar to our Idaho geology and have natural analogues that have remained unalteredfor geologic time, or are chemically neutral. To better understand the performance of these groutproducts in the SDA environment, physical properties of the grouts will be evaluated in this treatabilitystudy. Grouts will be evaluated in the laboratory with various representative waste matrices/interferencesand associated loading ratios to quantify effects on principal hydrologic characteristics of the set product.Correlative testing will also be performed on field-emplaced monolith samples. Testing will beperformed to allow extrapolation of an expected half-life or rate of dissolution for the grouted monolithand the associated thrust block cap in the SDA environment. This information is important in riskmodeling to ascertain the duration of physical stabilization and associated chemical buffering providedand the rate of change with time.

1.1.1.2 Chemical Stabilization. Chemical stabilization from the cementitious grouts will becalculated from test data and thermodynamic computations. Contaminant mobility may be expressed as afunction of solubility potential and a rate of diffusion and/or dissolution. Chemical effects on solubilityinclude two parts: chemical speciation of each contaminant and the equilibrium concentration of thecontaminants in the intergranular pore fluids (reference Section 8.4.3.5 for detailed discussion).Contaminant speciation both prior to and following grout emplacement will be computed using chemicalcomputations and historical information from site literature. The diffusion rate of the contaminant specieswill be computed from published diffusion coefficients and measured hydraulic properties of groutmaterials. These rates will be compared with the monolith rate of dissolution to identify the controllingrelease mechanism/rate for each of the contaminants of primary concern. These results will provide aframework for the interpretation and utilization of treatability study data in the risk model.

1.2 Confinement During RetrievalThe main test objective of the confinement during retrieval grout application is to reduce risk to

human health and the environment by eliminating or reducing the amount of airborne contaminants andassociated dust during waste excavation operations and exhumed waste handling. This study will producedata to verify that the application of a grout product prior to retrieval will effectively reduce airborneemissions, thus reducing requirements for operational confinement and/or personnel and environmentalprotection measures. It will also provide data to assess the introduction of grout additives and theireffectiveness against criticality concerns. These data will be assessed during the feasibility studyalternative evaluation (Figure 1-1). The successful application of confinement during retrieval to waste

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Figure 1-2. Modified well-dnlling apparatus used for jet grouting.

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excavation activities must be in compliance with the appropriate requirements for a radiologicallycontaminated site. These issues are described in Section 1.3.6. The main test objective will be supportedby addressing three data needs in the test design:

1. Dust Control—The airborne SDA contaminants and associated dust caused by excavationwill be controlled by the cohesive nature of the applied grout product. The degree of controlwill be measured in the field by a system of air samplers and personnel monitors.

2. Neutron Absorber Compatibility—The possibility exists that a petroleum-based substanceintroduced into SDA waste may act as a moderator of neutrons produced by radioactivecontaminants. A neutron absorber in the grout such as boron will reduce the amount ofavailable neutrons for fission. This is the same process used in nuclear reactors to controlthe fission process. Testing will be performed to evaluate the compatibility and distributionof such an absorber in the grout product.

Physical Stability (subsidence control)—The buried waste site is physically stabilized byinjecting grout material into the buried waste so that voids are filled, thus preventing sitesubsidence and surface water ponding. Tests and observation will be performed to evaluatethe waste site physical stabilization due to the grout.

1.3 SDA Background

1.3.1 Location

The Radioactive Waste Management Complex (RWMC) covers 70 ha (174 acres) in a naturaltopographic depression on the southwestem quadrant of the INEEL. The facility is divided into threeseparate functional areas: SDA, Transuranic Storage Area (TSA), and Administrative Area (Figure 1-3).The SDA is the primary focus of this treatability study. It is surrounded by a soil dike and perimeterdrainage channel and was initially established in 1952 as the Nuclear Reactor Test Site (NRTS) BurialGround on 5.2 ha (13 acres). The SDA has been used for shallow burial of solid radioactive waste. and itwas expanded to 35.6 ha (88 acres) and then to 38.8 ha (95.9 acre) in 1958 and 1988. respectively. TheTSA was a 22.7 ha (56.1 acres) parcel added onto the east side of the SDA that has been used for thestorage of transuranic (TRU) waste. The 8.9 ha (22 acre) Administrative Area includes administrativeoffices. maintenance buildings, equipment storage, and miscellaneous support facilities.

The region of interest for the WAG-7 Remedial Investigation/Baseline Risk Assessment includesthe RWMC facility, surrounding areas that may have received wind-blown contaminants, subsurfaceareas that may have received contaminants migrating laterally or vertically. and contamination of theSnake River Plain Aquifer which originated at the RWMC.

1.3.2 Review of SDA Geology

The SDA is located on the Snake River Plain in the gently rolling semiarid desert of southeasternIdaho. Surface topography of the region is determined by young (2000+ years) basalt lava flows andassociated volcanic features such as cinder cones, vents, pressure ridges. and collapsed lava tubes.Average annual precipitation is 8.7 in. At the SDA, depth to water table is about 580 ft (Becker et al.1998).

Soils are shallow at the SDA. 30 ft maximum depth to basalt. and are composed of clay. silt. andsand. Soil mineralogy is predominately clay minerals (50 wt%). quartz (37.5 wt%). calcite (10 wt%). iron

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Plant

Twe

Legend

I\-71 Parking areaConstruc(ion area

7 Undisturbed area(s)

Subsurface Disposal Are96 13 Acres

SDA)

Access entrance

Id Test plt

Administrative trailer

Support trailer

Origional cold test pit cells(non-intrusive tesfing) •

Previously disturbed barrow area

OFFSYurt

Figure 1-3. RWMC including SDA and Cold Test Pit.

r

Administrative Area

ransuranicStorage Are57.5 Acres

M96 0258

oxy-hydroxide, and other minerals (2.5 wt%) (Lee, Martins, and Weidner 1991). Soil moisture pH isalkaline, about 8 ± 0.5. The oxidation reduction potential (Eh) is oxidizing and is equivalent to air. Thesoil pH is buffered by the calcite-water-0O2 interactions. The soil Eh is buffered by oxygen in air. Thesoil moisture is saturated with respect to calcite, super-saturated with dolomite (Wood and Norell 1996),the iron minerals and probably the other soil minerals. Caliche is an impermeable, hard, concrete-like soilnaturally cemented by calcite and common in the SDA.

The bedrock is a series of generally horizontal basalt lava flows separated by thin, discontinuoussedimentary interbeds. Consequently, the overall structure is analogous to a "layer cake." Themorphology of the basalt flows is highly variable, from dense, massive material to vesicular and/or highlyfractured rock. Lava tubes are common. The interbeds are primarily unconsolidated sediments, cinders,and volcanic breccia. Air permeability measurements (Weidner et al. 1992) indicate that the permeabilityvaries through five orders of magnitude, from virtually infinite permeability to 0.05 D'Arcy.Measurements of natural air pressure fluctuation and attenuation as a function of depth indicate that theair permeability of the basaltic material sharply decreases at some depth between 71 and 105 ft belowground surface. The material at depths less than 71 ft are homogeneous, in terms of air permeability, as isthe material below 105 ft.

The hydrologic properties of the SDA are complex and are controlled both by the properties of theunderlying basalt bedrock complex and by the soil moisture content at a particular point in time. If theINEEL soil is saturated with water, or nearly so, the direction of water movement is generally downwarduntil it intersects relatively impermeable rock. At that point, the direction of water movement becomesroughly horizontal until a permeable zone (e.g., fractures), is intersected and the movement againbecomes vertically downward. If the SDA soil is unsaturated with water, the arid climate may cause thedirection of water movement to be upward, toward ground surface, because of evaporation and

1-7

transpiration at ground surface. The soil becomes saturated whenever water at ground surface isabundant. Typically, this occurs in the spring due to local snowmelt and flooding from the Big LostRiver. Rain during the remainder of the year is usually not sufficient to cause soil saturation. Many areasin the SDA contain voids and open space in and around the buried waste. Such regions are unstable andoften collapse when the soils are wet, thus changing the hydraulic properties. The collapsed areas areregions for potential surface water ponding and the development of channels for the movement of surfacewater directly into the waste.

1.3.3 Historical Waste Disposal Operations from 1952 to 1985

Past operations at the SDA are best discussed in four time intervals which share similar disposalpractices and waste types: early disposal (1952 to 1959), interim burial ground (1960 to 1963), the mid-to-late 1960s (1964 to 1969), and 1970 to 1985 (EG&G 1985). The information that follows was takenfrom (LMITCO 1995b and 1995c).

1.3.3.1 Early Disposal (1952 to 1959). The first trench at the NRTS Burial Ground was openedfor solid waste disposal in July 1952, and a total of ten trenches averaging 1.8 m wide, 274 m long, and3.7 m deep were used between 1952 and 1957 (Trenches 1 through 10). Pit 1 was used to dispose largebulky items in 1957.

Disposal practices depended on classification of the waste as either routine or nonroutine on thebasis of radioactivity. Routine waste produced exposures less than daily occupational limits and typicallyconsisted of paper, laboratory-ware, filters, metal pipe fittings, and other items contaminated by mixedfission products. Routine waste was packaged in cardboard boxes that were taped shut, collected indumpsters, and emptied into the trenches. Routine waste was not covered with soil until the end of anoperating week. Before 1957, there was no upper limit on radiation from waste, and items up to12,000 R/hour were buried. Items that produced exposures above daily occupational limits were treatedas nonroutine waste. This waste was placed in either wooden boxes or garbage cans, transported inspecial transport containers and vehicles, and immediately covered with soil.

Disposal documentation forms were not required until 1959, and early disposal records are sketchy.From 1954 to 1957, the NRTS Burial Ground accepted waste from the Rocky Flats Plant, and records didnot accompany the shipments. Instead, an annual summary of disposals provided total radionuclidecontent and waste volume. Rocky Flats Plant TRU waste was packaged in drums or wooden crates andstacked horizontally in pits and trenches beside mixed fission-product NRTS waste, and most of the pitsand trenches in the original burial ground contain a mixture of the waste types.

Until the late 1950s, trench locations were recorded by reference to metal tags placed at regularintervals along the barbed-wire enclosure surrounding the burial ground. Later, the ends of the centerlineand the corners of each pit were marked with concrete survey monuments. Each monument received abrass plate stamped with the trench or pit number, dates the trench or pit was opened and closed, and adirection arrow. Older disposal sites were retrofitted with monuments, but the accuracy of the locations isuncertain.

1.3.3.2 lnterim Burial Ground (1960 to 1963). Trenches 16 through 25 and Pits 2 through 5were open for disposal of waste between 1960 and 1963.

Burial Ground operations changed during this period as a result of the delegation of authority tomanage and operate the burial ground from the Atomic Energy Commission to the NRTS operatingcontractor. The contractor began to manage radiological surveillance, arrange nonstandard disposal,refine and formalize standard disposal practices, and implement a recordkeeping system.

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In the late 1950s, the Atomic Energy Commission determined that land disposal was preferable tooffshore ocean disposal of solid radioactive waste. Commercially-operated land disposal sites were notavailable for disposal of waste from commission-licensed private industry at the time, and thecommission created an interim disposal program to receive solid radioactive waste from licensees whilecommercial sites were established. The NRTS Burial Ground was part of this interim disposal program,and the burial ground disposed of approved shipments from offsite generators together with Rocky FlatsPlant and NRTS waste during this period. Waste from the three sources was commingled and eitherstacked or dumped into the pits and trenches.

1.3.3.3 Mid-to-Late 1960s (1964 to 1969). By the mid-1960s, concern about worker safety andenvironmental impacts of waste disposal, especially potential impacts on the quality of water in the SnakeRiver Plain Aquifer, began to influence waste management. Disposal practices, monitoring systems, andthe adequacy of facilities were scrutinized, and legislation was passed. Drums from the Rocky Flats Plantwere dumped rather than stacked in pits to reduce labor and control personnel exposures. Environmentalmonitoring was improved by placing film badges around the perimeter of the burial ground, and thesefilm badges were later replaced with 18 thermoluminescent dosimeters. Water samples from thesubsurface were collected and analyzed, and field investigations were conducted to assess waste leaching.Studies by various agencies recommended improvements in monitoring and steps to mitigate potentialimpacts from continued waste burial.

Burial procedures were modified to increase the minimum trench depth from 0.9 to 1.5 m (3 to5 ft), line the bottoms of excavations with at least 0.6 m (2 ft) of soil, compact the waste by dropping aheavy steel plate on it, and increase soil cover to a minimum of 0.9 m (3 ft). Transuranic waste disposal,including disposal of plutonium-contaminated waste, ceased in 1969; and all subsequent TRU wastecontainers were stored above ground at the TSA.

1.3.3.4 Disposals from 1970 to 1985. The greatest departure from previous disposal practicesduring this period was implementation of the 1970 Atomic Energy Commission "Policy StatementRegarding Solid Waste Burial" (EG&G 1985; AEC 1970), which required segregated and retrievablestorage of TRU waste. Originally, TRU waste was defined as waste contaminated with TRUradionuclides in activities greater than 10 nCi/g; but in 1982, the TRU waste was redefined to be materialscontaining any alpha-emitting radionuclide with an atomic number greater than 92, a half-life longer than20 years, and activity greater than 100 nCi/g at the end of institutional control. The Atomic EnergyCommission also committed at this time to remove buried and stored TRU waste from the NRTS(DOE-ID 1979, Appendix A).

A pad was constructed in the TSA for segregated and retrievable storage of TRU waste. This padwas originally called the "Engineered Waste Storage Area," but the name was changed to the"Transuranic Disposal Area," and then to Pad A. From 1972 to 1978, boxes were stacked around theoutside of Pad A while drums were stacked inside in staggered horizontal layers and covered with soil.The pad and waste were covered with a final layer of at least 0.9-m (3-ft) of soil, which was contoured toa maximum 3:1 slope and seeded with grass.

Practices were modified to expand the usable disposal volume and extend the operational life of theSDA. Modifications included waste compaction, more stringent waste packaging, and increased pitdepths. The Naval Reactor Facility began compacting waste in 1971; and, by 1974, waste from INEELfacilities other than the Naval Reactor Facility was sorted and non-TRU compactible waste was shippedto the RWMC in plastic bags for compaction. The volume of disposal pits was expanded by using heavyequipment to remove fractured basalt from the excavations. Beginning with Pit 17 in 1980, explosiveswere used to deepen pits. Excavations were lined with at least 0.6 m (2 ft) of soil (and beginning in 1985

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with a geotextile liner) before waste was interred, and the final compacted soil cover was at least 0.9 m(3 ft) thick. Beginning in 1978, waste was stacked in a close-packed array in the pits.

Disposal practices also were modified to minimize personnel radiation exposures. Between 1977and 1981, soil vaults were used to dispose waste with beta-gamma exposure rates greater than500 mR/hour at a distance of 0.9 m (3 ft). Vaults were emplaced in rows in areas not suited for pits andconsisted of 0.4 to 2 m (1.3 to 6.5 ft) diameter vertical cylindrical shafts that averaged approximately3.6 m (12 ft) deep. The vaults were set at least 0.6 m (2 ft) apart, and at least 0.6 m (2 ft) of soil wasplaced in the hole if basalt was penetrated during drilling.

Trenches also received high-radiation waste until trench disposal was discontinued in 1981. After1981, the unfilled trench area was redesignated for soil vaults. General disposal practices were the samefor pits, trenches, and soil vaults: compacted waste was bailed; larger, bulky items were wrapped inplastic; and smaller noncompactible waste was contained in wooden boxes covered with fire retardantpaint. Waste was placed into the excavations by free-air transfer or in shielded casks depending on theexposure rate measured on the outside of the waste container. Full disposal areas were crowned with afinal soil cover at least 0.9 m (3 ft) thick and compacted to promote natural drainage.

1.3.4 Contemporary Operations, 1986 to the Present

Disposal practices have not changed significantly since 1985. However, details about the handlingof various types of waste have become readily available due to improvements in documentation(LMITCO 1995, DOE-ID 1997b). Each waste shipment arriving at the RWMC is visually examined fordiscrepancies in documentation and damage to packaging and surveyed to ensure that radiation andcontamination readings meet RWMC waste acceptance criteria requirements (DOE-ID 1993; 1997a).Any abnormalities are resolved with the generator before the waste is accepted. Once accepted, the wasteis transferred to the TSA or the SDA as appropriate.

1.3.4.1 Contemporary Disposals Within the SDA. Trench burial was discontinued in 1981.Since that time, low-level waste (LLW) has been disposed in pits, soil vaults, and concrete vaults. Pits 17through 20, including concrete vaults within Pit 20, and soil vault rows 17, 18, and 20, are presentlyactive. LLW emplaced in the SDA is classified as remote-handled if radiation levels 1 m (3.3 ft) from thepackage surface exceed 500 mR/hour. Remote-handled waste is entombed in either a soil or concretevault. Contact-handled LLW has lesser exposure rates and is stacked in the pits. Large bulky itemsunsuitable for vault disposal are buried occasionally in a pit even though the exposure rate exceeds500 mR/hour.

1.3.4.2 Pit Disposals. Pits 15 and 16 are closed, but the boundaries between the two pits andPits 17 and 18 are only administrative (Yokuda 1992). The boxes on the west side of Pits 15 and 16 havebeen covered with soil for shielding, while disposal continues within the large open area of Pits 17through 20. A contoured earthen berm surrounds Pits 17 through 20.

Waste meeting acceptance criteria is stacked within the pits using forklifts and cranes. The stackheight is limited by the strength of the containers and by administrative controls that specify a maximumheight of 7.3 m (24 ft). As areas of the pits become full, waste is covered with at least 1 m (3.3 ft) of soil,which is compacted, sloped for drainage, and seeded with a sod-building grass.

1.3.4.3 Soil Vault Rows. Soil vaults are permanent subsurface receptacles for remote-handledLLW. The soil vaults are unlined holes bored 5.2 to 7.6 m (17 to 25 ft) deep that receive containerizedwaste from bottom-discharge shipping casks. Full vaults are covered with soil that must be at least 0.9 m(3 ft) thick and produce exposure rates less than 1 mR/hour at the soil surface above the covered vault.

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According to RWMC personnel, much more than 0.9 m (3 ft) of space is usually left for the soil cover.Exact soil thickness is not recorded, but most soil vaults have at least 1.8 m (6 ft) of cover.

1.3.4.4 Concrete Vaults. Concrete vaults are located in the southwest corner of Pit 20 and weredesigned to conserve space within the SDA. The concrete vaults, like the soil vaults, are used for remote-handled LLW and receive waste from the same bottom-discharge shipping casks. The vaults wereconstructed in precast reinforced concrete sections that rest on an integral base plate and are capped witha concrete plug. The vaults are configured in honeycomb arrays, with each array being surrounded bysoil for additional shielding and seismic stability. Voids between vaults in an array are filled with sand.

1.3.5 Contaminants of Potential Concern

Maximum carcinogenic risks and hazard indices for the OU 7-13/14 contaminants of potentialconcern, based on a 1,000-year simulation period, were previously identified in the Interim RiskAssessment for WAG 7 (Becker et al. 1998). The list is provided in Table 1-1. The years in which thepeak risks occur, and the major pathways contributing to the total risks are provided in the table. Thosecontaminants with a hazard index greater than 1 or a risk greater than or equal to 1E-06 are highlighted.

The radionuclides C-14, Cs-137, 1-129. Np-237, Sr-90, Tc-99, U-234, and U-238. and the chemicalcarbon tetrachloride have peak risk values greater than 1E-04. Contaminants with a carcinogcnic risk inthe range of 1E-06 to 1E-04 include the radioisotopes Ac-227 (after 10.000 years), Am-241. C1-36,Nb-94, Pa-231 (after 10.000 years). Pu-239. Pu-240, Ra-226, U-233. U-235. and U-236 and the❑onradioactive contaminant methylene chloride. Contaminants with a total hazard index greater than 1.0are carbon tetrachloride, nitrates, and total uranium.

Although the peak risk for Co-60 and the peak hazard quotient for hydrazine exceed screeninglimits, these two contaminants are not identified as risk drivers for WAG 7. The Co-60 risk wasdominated by the external exposure pathway with the peak risk occurring in the year 1981 and fallingbelow 1E-06 by the year 2013. Based on the short half-life for Co-60 (5.21 years), it can be eliminatedfrom further risk evaluation. According to the Environmental Protection Agency (EPA) 1997, the half-life of hydrazine in the environment is 2 to 20 days. The hydrazine would degrade before any exposurecould occur.

1.3.6 Double Confinement Requirement for Excavated Waste

Double confinement has been proposed for retrieval of buried TRU waste (McQuary et al. 1991).The term "double confinement" usually refers to a building within a building (two structures). It may bepossible to use in situ grout as one of the "confinements" mechanisms. ln addition. in situ grout mayallow bubble-suited entry to a retrieval area, which could further reduce the costs associated with retrievalby allowing manned maintenance and possibly manned retrieval (in a bubble suit).

Typically, confinement is defined as a physical barrier such as a structure, glove box. piping, etc..coupled with ventilation. The purpose of confinement is to contain the hazards and prevent or minimizethe release to the environment. In DOE Order 420.1, grout is considered to be a method of confinement.The order states. "All nuclear facilities with uncontained radioactive materials (as opposed to materialcontained within drums, grout, and vitrified materials) shall have means to confine them.-

Grout, if used as the primary component of thc double confinement system, must maintain airborneand removable contamination control in accordance with the DOE Radiological Control Manual,Articles 222 and 223. Airborne contamination control is based on the derived air concentration. Thederived air concentration is the concentration of airborne alpha radioactivity which. if inhaled by a worker

Table 1-1. Interim risk assessment (Becker et al. 1998) simulated peak risks and hazard indices for the

l.000-year simulation period.

Contaminantof Potential Peak

Concern Risk Year

PeakHazard

Index Year

Primary 1.000-year

Exposure Pathway

Radionuclide Contaminants

Ac-227a 5.E-07 2967b NA' NA Groundwater ingestion

Am-241 8.E4-05 29676 NA NA Soil ingestion, inhalation, external exposure, andcrop ingestion

Am-243 2.E-08 29676 NA NA External exposure

C-14 fi,g79,41. 2967s NA NA Groundwater ingestion

C1-36 7.E-06 2247 NA NA Groundwater ingestion

Cm-244 2.E-10 2104 NA NA External exposure

Co-60d 4.E-06° 1981 NA NA External exposure

Cs-137 rit. 7-020:11' 2097 NA NA External exposure

Eu-152 7.E-08 1991 NA NA External exposure

Eu-154 2 E-07 1985 NA NA External exposure

H-3 7.E-07 2097 NA NA Groundwater ingestion

1-129 :2.EE.04i, 2116 NA NA Groundwater ingestion

Na-22 9.E-1 l 1981 NA NA External exposure

Nb-94a 1 E-06 2967b NA NA External exposure (groundwater ingestion)

Ni-59 7.E-08 2967b 4 E-07 2967s Crop ingestion

Ni-63 3 E-08 2253 7 E-11 2254 Crop ingestion

Np-237 vezo.4.;A 2967 NA NA Groundwater ingestion

Pa-231 a 5 F-07 29676 NA NA Groundwater ingestion

Pla-210a 8.E-07 2967b .., ., Soil and crop ingestion

Pu-238 8.E-09 2254 NA NA Soil and crop ingestion

Pu-239 2.E-05 2967e NA NA Soil and crop ingestion

Pu-240 5.E-06 2967b NA NA Soil and crup ingestion

Pu -241 I .E-11 1999 NA NA Soil ingestion

Pu-242 9.E-10 2967 NA NA Soil and crop ingestion

Ra-226 5.E-05 2967b NA NA External exposure

Ra-228 1.E-07 2967e NA NA External exposurc1474.t7c,i-45c

Sr-90 i.8.E.t041;:: 2097 NA NA Crop ingestion

Tc-99 Sifi etto 2126 NA NA Groundwater ingestion and crop ingestion

.11-228 3.E-07 2967h NA NA External exposure

Th-229 2.E-08 2967b NA NA Groundwater ingcstion

l'h-230 2 E-08 2967b NA NA Groundwater ingestion

Th-232 4 E-10 2967b NA NA Crop ingestion

U-232 1.E-07 2219 - r i Groundwater ingestion

U-233 2.E-06 2967" i hi Groundwater ingestion

U-234 2,,E,04 2967b , I, IGroundwater ingestion

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Table 1-1. (continued).

Contaminantof PotentialConcern

PeakRisk Year

PeakHazardIndex Year

Primary 1,000-yearExposure Pathway

U-235 1.E-05 2967b —f —hi Groundwater ingestion

U-236 8.E-06 29671" —f Groundwater ingestion

U-238 2967b —r Groundwater ingestion

Nonradionuclide Contaminants

Acetone NA NA 7.E-03 2300 Groundwater ingestion

Antimony NA NA 7.E-05 2967 Groundwater ingestion

Beryllium 5E-10 2967 6.E-08 2967 Crop ingestion

Butanone NA NA 3.E-04 2295 Groundwater ingestion

Cadmium 6.E-12 2967 1.E-04 2967 Inhalation and crop ingestion

Carbon tetrachloride 1968 ;1.E+01 2105 Inhalation and groundwater ingestion

Chromium 3.E-15. 2159 4.E-02 2732 Groundwater ingestion

Hydrazine. 2.E-05g 2280 NA NA Groundwater ingestion

Lead NA NA NAh NAh NA

Mercury NA NA 5.E-03 2967b Crop ingestion

Methylene chloride 4.E-05 2186 2.E-011 2185 Groundwater ingestion

Nickel NA NA 4.E-09 2967 Crop ingestion

Nitrates NA NA 4.E+00 2097 Groundwater ingestion

Tetrachloroethylene(PCE)

NA 1952 5.E-01! 2137 Groundwater ingestion and dermal exposure tocontaminated water

Total uranium 1.E+01 2967 Groundwater ingestion (primarily because ofU-238)

Note: For toxicological risk. the peak hazard index is given. and for carcinogenic probability, the peak risk is given.Green = the contaminant is retained for evaluation in the WAG-7 comprehensive RI/FSRed = carcinogcnic risk > 1E-04Blue = carcinogenic risk between 1E-06 and 1E-04Pink = toxicological (noncareinogenic) hazard index > I.O.

a. The contaminant is retained. Though unacceptable groundwater ingestion risks are not predicted in the 1.000-year simulation period. risk isgreater than 1E-06 in thc 10,000-year growidwater ingestion scenario.b. The peak risk and hazard index for the contaminant do not occur before the end of the 1.000-year simulation period. Therefore. groundwateringestion risks and hazard indices were simulated for the peak concentration occuning wilhin 10,000 years. These results are not presented inthis tablc.c, NA = not applicabled. Cobalt-60 was eliminated from further evaluation. The peak risk is predicted to have occurred in 1981. Based on the short half-life of Co-60(5.3 ycars), radioactive decay rapidly reduced external exposure risks.c. The total toxicological hazard index from all lead isotopes is reported under nonradionuclide contaminants.f. The total toxicological hazard index from all uranium isotopes is reported under nonradionuclide contaminants.g. Hydrazine is elinnnated from further evaluation. Degradation mechanisms. except for radioactive decay. were not considered in the interimrisk assessment. However. hydrazine has an environmental half-life of only 2 to 20 days (EPA 1997). and the simulated risk is grosslyoverestimated.h. Lead noncarcinogenic effects were predicted using the EPA Integrated Exposure Uptake Biokinetic modcl. No unacceptable levels werepredicted.i. The inventories for methylene chloride and ietrachloroethylene may be underestimated by a factor of 4. Therefore. noncarcinogenic hazardindices for these two volatile organic compounds will bc reevaluated in the bascline risk assessment.j. Uranium carcinogenic risks are reported by uranium isotope under radioactive contaminants.

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over one working year, would cause the worker to reach the annual intake limit (10 CFR 835,Appendix A). Radiation control procedure MCP-356 requires posting of an area at 2% of applicablederived air concentration and respirator protection at 10% or higher of the derived air concentration. TheDOE Radiological Control Manual defines removal contamination as "radioactive material that can beremoved from surfaces by nondestructive means, such as casual contact, wiping, brushing or washing."Removable contamination is based on the acceptable limit for transuranic radioactive elements.Article 222 of the DOE Radiological Control Manual states that removable contamination shall notexceed 20 dpm/100 cm2.

In order to allow unrestricted entry to an area, the airborne alpha activity concentration must becontrolled to over 99.99%.a It is unlikely that any contamination control strategy could ever achieve thisgoal. However, to allow bubble-suited entry would only require a 90% control of dust and using paraffinas a pretreatment of the buried waste prior to retrieval may achieve this goal. Manned bubble-suitedmaintenance or remote retrieval equipment is much easier and more cost effective than remotemaintenance. In addition. it is possible that evaluation of the data obtained from the grout/retrieval studymay allow regulators and the agencies to agree to a single containment structure thus saving one physicalstructure.

In summary. the grout/retrieval concept may allow bubble-suited entry to a retrieval arena thatcould allow possible nonremote evacuation/maintenance (faster and more cost effective than remoteoperations). In addition, the final triparty agreement for OU 7-13/14 may allow single containmentstructures, which is also a cost savings over conventional multiple containment structures.

1.4 In Situ Grout Background

1.4.1 In Situ Grout Method

In situ grouting can be applied to achieve two fundamentally different goals. Grouting canstabilize waste in place for 1,000 to 10,000 years or more. On the other hand, in situ waste stabilizationcan be a pretreatment to allow the buried waste to be excavated more safely and efficiently for finaltreatment and disposal elsewhere. In both cases, the basic procedure for stabilizing the buried waste insitu is the same. A grout material selected for the specific application is injected at high pressure andvelocity into the buried waste site using a modified well-drilling apparatus (see Section 2.2). The highvelocity of the injected grout results in a mixture of waste, soil, and grout filling the void and pore spaces.

1.4.2 In Situ Grout Variables

1.4.2.1 Grout for Long-Term Waste Disposal Stabilization. Characteristics of successfulapplication and performance of in situ grout for long-term disposal (1,000 to 10,000 or more years) at theSDA will include six variables of success.

1. Role Played by the "Thrust Block." The thrust block is a concrete barrier at ground surfacethat prevents the infiltration of surface water. The thrust block is designed to controlcontamination spread and grout returns during the jet-grout operation. However, it ispermanent and remains in place after the jet-grout operation and can act as a concrete barrierto support an impermeable surface cap for a treated area.

a. Assuming plutonium/americium oxidcs movc like dust panicles. 99 9% is a percentage of dust removal ovcr a base case inwhich no controls arc applied

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2. Physical Stabilization of the In Situ Waste. At the SDA, undesirable collapse and subsidenceof the soils into subsurface void space occurs during wet weather conditions. Suchsubsidence is unacceptable for long-term site stabilization because it changes the localhydraulic properties by causing ponding of surface water and the development of channelsdirectly into the waste. A cap cannot be constructed on a physically unstable site. In situapplication of an appropriate grout would fill the subsurface void space and prevent sitesubsidence.

3. Hydraulic Properties of the Buried Waste in the Site. If water is prevented from transportingwaste material from the site, then the risk from nonvolatile contaminants is minimized. Thisaspect of the problem can be addressed by applying a grout material that produces amonolith having a low hydraulic conductivity. A hydraulic conductivity requirement cannotbe explicitly specified (because it is not an independent variable and it must be evaluatedtogether with other factors to estimate risk). In general, the treated site hydraulicconductivity must be less than the surrounding untreated soils. In the ideal case, asufficiently low permeability minimizes the risk due to contaminate transport from a buriedwaste site because all fluid flow is insignificant.

4. Solubility of the Waste Constituents in Groundwater. The appropriate in situ grout canchange the solubility of the waste constituent into an insoluble form by changing the Eh andpH of the groundwater. The transport of nonvolatile waste components is affected by thesolubility (among other variables) of the waste component in groundwater. The predictionof the chemical behavior of waste components transported by groundwater is based on thefundamental assumptions that the chemical properties of the groundwater of the waste sitecontrol the dissolution and precipitation of the waste components. If the chemical propertiesof natural groundwater affect the chemical behavior of the waste components, then thechemical nature of the groundwater altered by grout materials must also affect the wastecomponents.

If the waste components are in an insoluble form, the health risk is reduced because thewaste components are not effectively transported in solution by groundwater. Some groutsdo not significantly affect the groundwater properties. In this case, the chemicalenvironment affecting waste chemical mobility will be that of SDA groundwater (i.e., pH8 ± .05 and Eh identical to oxygen), and chemical equilibrium with calcite and clay minerals(illite and chlorite). While other grouts affect only the pH of the groundwater, some groutsaffect the properties more than others, e.g., solutions in contact with cementitious grouts thatcontain Ca(OH)2 typically have pH >10, in contrast to other cementitious grouts thatproduce a pH of about 9. Some grouts change both the Eh and the pH of the groundwater(e.g., grouts containing blast furnace slag).

5. Implementability of the Grout. The grout production and application quality control must beeasily and inexpensively maintained. The material must be routinely produced and applied.The required performance properties must be insensitive to normal variation in productioncontrols. In addition, the grout must not possess unacceptable health or safety risk topersonnel or the environment. In general, barrier materials that are flammable, toxic, havecure temperatures above 100°C, or possess other hazardous properties or components areundesirable. In these cases, special precautions are required to protect worker safety and theenvironment and are best avoided if possible. Suitable materials that do not have these riskscan usually be developed.

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6. Durability of the In Situ Grout Material (e.g., Monolith). The in situ grout material musthave the capability to provide protection to human health and the environment for longperiods (1,000 to 10,000 years). To estimate how long the grout will affect chemicalproperties of groundwater requires knowledge of the dissolution rate of the grout. Ingeneral, the lifetime of the grout material will be determined by the grout weathering rate inthe subsurface environment (depth in soil of 2 to 8 m at SDA) of the waste disposal site.The rate of weathering will be primarily controlled by chemical interaction between thegrout material and the natural constituents in soil and water. The grout is probably too farbelow ground surface (more than one meter) to be significantly affected by weatheringprocesses at ground surface such as freeze-thaw and wet-dry cycles.

In summary, an acceptable in situ grout must maintain a low level of risk to human health and theenvironment for a long time and must also be implementable. The risk-level goal may be achieved byapplying an in situ grout to minimize the effect of site hydraulic properties or chemical properties or acombination of both. The desired properties include the prevention of groundwater movement throughthe grout and minimization of waste solubility. The acceptability of the grout can be evaluated on thebasis of the reduction of risk due to the contributions from each factor as noted above.

1.4.2.2 Grout for Confinement During Retrieval. The primary purpose of in situ grout as apretreatment for waste retrieval is to suppress dust for safety and as low as reasonably achievablepurposes. The following are variables that affect the selection of the grout material for confinementduring waste retrieval.

1. The "implementability of the grout. The grout production and application quality controlmust be easily and inexpensively maintained. The material must be able to be routinelyproduced and applied. The required performance properties must be insensitive to normalvariation in production controls. In addition, the grout must not possess unacceptable healthor safety risk to personnel or the environment.

2. The reduction of dust and effects on digging properties during retrieval.

3. The effect of the grout on the transport and handling properties of the waste prior to finaltreatment and disposition.

4. The effect of the grout material on the final waste treatment method and disposition.

In summary, the ideal grout material for waste containment during retrieval would be safely andeasily applied. It would increase the safety and efficiency of the waste handling and treatment process bysuppressing dust, which would make the excavated waste material safe and easy to handle, and wouldfacilitate final treatment of the waste.

1.5 Preliminary Regulatory Requirements

Following is a list of preliminary applicable or relevant and appropriate requirements (ARARs) forthe in situ grouting treatability study. A detailed applicability analysis of the regulations andrequirements will be documented in the treatability study test plan and safety planning documentation.

In situ grouting will first be demonstrated in a "cold pir outside the SDA and will not involve theplacement or treatment of hazardous waste. Hazardous waste ARARs will not be applicable to the fieldpit tests because hazardous waste will not be placed into the pit. However, any waste materials from theproject must be subjected to a hazardous waste determination prior to disposal.

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Hazardous waste determination and land disposal restriction evaluation will be completed on allsecondary wastes such as filters, personnel protective equipment, sample waste, and decontaminationsolutions. All wastes from the treatability study will be managed as CERCLA investigation-derivedwaste.

Samples that are altered will be either retumed to the INEEL for ultimate waste disposal ormanaged at the laboratory in accordance with the laboratory's Task Order Statement (this includesactivities requiring neutralization. Hazardous waste ARARs may be applicable to secondary wastes, e.g.,Investigation-Derived Waste, generated during the treatability study. Note, however, that treatabilitystudy samples fall under the TS sample exclusion as defined in 40 CFR 261.4 (also addressed inTable 4-2, ARARs table).

Ultimate investigation-derived waste disposition will be determined in the final CERCLA Recordof Decision for the SDA (Section 11). Final management of wastes will be addressed in the WasteManagement section of the In Situ Grouting Test Plan.

Toxic Substances Control Act regulations are not applicable to this project. Polychlorinatedbiphenyls or Toxic Substances Control Act-regulated constituents will not be encountered or used for thetreatability study.

No new drinking water or waste water systems will be installed and no existing systems will bemodified for this project.

Air-emission issues from the project will include limited fugitive dust and no toxic air emissions.Some portable equipment will be used at the project.

A backup electrical generator will be fueled from a small storage tank located on the sametruck/trailer as the generator. A separate fuel tank will not be required.

There are no known impacts to archeological or historical sites or endangered species from eitherset of tests.

The ARARs for this project are presented in Table 1-2.

1.6 In Situ Grouting Target Inventory

During the evaluation of the target inventory for the proposed in situ grouting applications, it wasdetermined that data gaps existed. The analysis estimated in situ grouting performance against theconstituents listed in Table 1-1 and whether in situ grouting would adversely be affected by certain typesof waste materials. The detailed in situ grouting target inventory evaluation is shown in Appendix B,Table A-1.

The evaluation identified several data gaps for the two treatment options. These data gaps wereneeded to calculate or determine the following variables.

• Dissolution rate of the grout used for long-term waste stabilization (to determine the half-lifeof the monolith). The data will be used in the risk assessment model to predict release rateof monolith contaminants.

• Hydraulic conductivity of treated buried waste when stabilized for long-term disposal willalso be used in the risk assessment to predict release rates in the monolith.

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Table 1-2. In situ grouting ARARs.

Statute, Regulation, or Order

Toxic Substances Idaho Air Pollution Act(IDAPA) 16.01.01.161Preconstruction Compliance w/Toxic StdsIDAPA 16.01.01.210Toxic Air EmissionsIDAPA 16.01.01.585-.586

Requirements for Portable EquipmentIDAPA 16.01.01.500.02

Fugitive DustIDAPA 16.01.01.650 and .651

National Emission Standards for HazardousAir Pollutants (NESHAPS) — RadionuclideEmissions from DOE Facilities,40 CFR 61.92Emission Monitoring, 40 CFR 61.93Emission Compliance, 40 CFR 61.94(a)

Hazardous Waste - Hazardous wastedeterminationIDAPA 16.01.05.006, 40 CFR 262.11

Use and Management of ContainersIDAPA 16.01.05008 (40 CFR 264.171-178)Subpart I

Compatibility of waste with containers(40 CFR 264.172)

Idaho Groundwater Quality RuleIDAPA 16.01.11.200

National Pollutant Discharge EliminaSystem (NPDES), Stormwater40 CFR 122.26

Spill Prevention, Control, andCountermeasures (SPCC)40 CFR 112.3(b) and 112.7

Requirement

Idaho air regulations limit releases of toxic substances fromstationary and portable sources of air emissions. Sources mustestimate toxic emissions prior to construction and impose airpollution control equipment if necessary. Toxic emissions mayrequire routine monitoring during operation.

Idaho air regulations require portable equipment to operate withinstate and federal air emissions rules.

Idaho air regulations require sources producing fugitive dust totake action to limit dust suspension.

These federal air regulations apply to emissions of radionuclidesfrom DOE facilities and limit the radiation dose to offsitepersonnel. Radionuclide emissions must be reported to the INEELAir Program for aggregation with other INEEL sources.

Secondary wastes generated during the tests must be subjected to ahazardous waste determination prior to disposal. Thedetermination must be formal and maintained as part of the projectrecords.

Management of secondary wastes (which are characterized ashazardous waste) generated from this activity will be managed inaccordance with the substantive requirements specified in thissection.

Containers used for storage of hazardous wastes generated fromthe treatability study will be compatible with the wastes generated.

These rules establish specific numeric standards for groundwatercontaminants that must not be exceeded in waters of the state.

on These regulations address stormwater runoff from variousoperations including ground disturbance or excavation andhazardous waste storage and treatment operations. Stormwaterrunoff shall meet specific limitations on contaminantconcentrations.

While a formal SPCC Plan is an administrative requirement,operational procedures should meet the intent of theserequirements if a discharge of oil, in harmful quantities, to watersof the United States is possible.

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• Effect of organic materials and nitrate salts on grout properties, applicable to grouts usedboth for long-term disposal application and for confinement during retrieval. Thisqualitative data will be used to determine maximum waste loading.

• Effectiveness and implementability of boron-modified paraffin-based grout for confinementduring retrieval. The results will be a maximum concentration that a boron compound canbe added to paraffin to get a homogenous distribution. The data will be used to estimateeffectiveness for criticality issues.

The major findings from the evaluation are discussed below.

A summary of the effect of some contaminants is given below. In order to minimize confusion, thefollowing nomenclature will be followed. The term "waste matrie is used to identify components of thewaste material which, because of their abundance, may affect the properties of the grout. Examplesinclude nitrate and organic compounds. The term "contaminant" is used for those potentially hazardouscomponents of the waste that are present in quantities too small to affect the properties of the waste.Examples of these include plutonium, radiogenic carbon, arsenic, etc.

Carbon Tetrachloride and Other VOCs—Carbon tetrachloride and other volatile organiccompounds (VOCs) are present in SDA soil gas and absorbent material in waste containers and soil.These contaminants are transported primarily by gas phase diffusion. The ability of the grout material totreat such contaminants depends almost solely on the reduction in air permeability achieved by the grout.Because the gas diffusion rate is in meters per day, the effectiveness of grout materials will probably besmall. In high concentrations, VOCs will prevent some grouts from setting or otherwise degrading groutperformance, both for long-term durability and confinement during retrieval. The VOC concentrationnecessary to adversely affect grout performance will be determined.

Uranium Uranium becomes mobile in groundwater that contains abundant carbonate ion, whichis oxidizing and has high pH. Grouts that cause excessively high pH are undesirable. Uranium solubilityin water is very low in alkaline solutions provided the water is also reducing (Shoemaker et al. 1995).This issue concems long-term durability, not confinement for retrieval.

Neptunium, Plutonium, and Other Actinide Contaminants—Plutonium, neptunium, and the actinideelements are precipitated as insoluble oxide materials in alkaline solutions (Shoemaker et al. 1995). Thegrout material developed at Savanna River (Shoemaker et al. 1995) was designed to chemically changethe actinide contaminants into insoluble materials by producing alkaline and reducing solutions. Sincefissile isotopes are present in the waste, a criticality safety program must be implemented. Thepreliminary criticality safety concems for in situ remediation are addressed in Appendix C.

Strontium—The reduction of the hydraulic conductivity by the grout will be the primarymechanism for the immobilization of strontium. This issue concerns long-term durability, notconfinement for retrieval.

Strontium behaves chemically very much like calcium and, in the SDA environment, is generallyconcentrated in calcium-rich minerals and materials. Because the SDA groundwater is calcium saturated,the chemical weathering of cementitious grout will be immediately followed by the precipitation ofcalcite and the immobilization of some strontium at the same time.

Cesium—In situ grouts will decrease the mobility of cesium primarily by reducing the hydraulicconductivity of the waste site. This issue concems long-term durability, not confinement for retrieval.

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Cesium is chemically very similar to potassium and is concentrated with potassium minerals innature. The natural clay minerals, particularly illite, found in the SDA soils in which the waste is buriedare natural cesium immobilization materials. SDA soil contains 50 wt% clay minerals (Weidner et al.1992).

lodine—The in situ grout immobilization of iodine in groundwater will rely on the ability of thegrout material to prevent the movement of groundwater through the waste. This issue concerns long-termdurability, not confinement for retrieval.

Technetium—Technetium is mobile in groundwater when it is in one of its two highest oxidationstates. A reducing environment causes technetium to become insoluble (Bostick et al. 1996). The saltstone waste stabilization material developed at Savannah River was designed to immobilize technetium(among other contaminants). Blast fumace slag was used to provide the reducing environment andimmobilize technetium as an insoluble sulfide (W.S.R.C. 1992). This issue concerns long-termdurability, not confinement for retrieval.

Carbon—The reduction of the hydraulic conductivity by the grout will be the primary mechanismfor the inmiobilization of carbon. This issue concerns long-term durability, not confinement for retrieval.

In regard to estimating carbon mobility, the chemical state of the C-14 contaminant in the SDA isimportant. ff it is an activation product in steel (Becker et al. 1998), then the carbon-14 may be in achemically inert form as iron or chromium carbide or as elemental carbon. If it is in any other form, it ispotentially soluble in groundwater and soil gas. The chemical weathering of cementitious grouts releasescalcium which, in the calcium saturated groundwaters at the SDA, reprecipitates as calcite, CaCO3.Carbon-14 will be immobilized in the calcite together with nonradiogenic carbon.

Nitrate Compounds—The grout will reduce the hydraulic conductivity of the waste site,minimizing the dissolution and mobilization of nitrate materials by groundwater. Nitrate compounds mayprevent some grouts from setting. The nitrate concentration necessary to adversely affect groutperformance will be determined. This applies to grout formulations used for long-term durability andconfinement for retrieval.

Organic Sludge—Organic sludge will be physically encapsulated by grout. Groundwater will beprevented from moving through the organic sludge. Organic materials may prevent some grouts fromsetting. The organic concentration necessary to adversely affect grout performance will be determined.This applies to grout formulations used for long-term durability and confinement for retrieval.

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2. REMEDIAL TECHNOLOGY DESCRIPTION

2.1 Previous INEEL Stabilization Studies

From 1994 through 1997, a series of applied research tests which showed that buried waste couldbe stabilized and contained using appropriate grouting agents and jet-grouting emplacement techniqueswere performed at the INEEL with funding from EM-50. Materials suitable for both long-term disposaland confinement during retrieval were demonstrated. In summary, the demonstrations showed proof ofconcept in field testing and as a remedial option for application at the SDA. Findings from these studieswere used to support planning of the treatability study for the in situ grouting technology. These previousin situ grouting programs are summarized in the following sections.

2.1.1 Innovative Grout/Retrieval Demonstration

In 1994, a demonstration of the grout/retrieval technology was performed at the INEEL by theBuried Waste Integrated Demonstration for the DOE Office of Technology Development. Simulatedburied waste was stabilized using jet-grouting techniques and then the resultant monolith was retrieved(Loomis and Thompson 1995a).

A simulated waste pit was constructed using cardboard and steel drums and cardboard boxes full ofsimulated waste. A rare-earth tracer was placed in each container to simulate a worst-case loading of theTRU contaminant. The pit was built similar to pits found in the SDA using typical INEEL soil asbackfill. The first phase involved the injection of grout. The second phase involved application ofdemolition grout. The third phase involved using a backhoe to retrieve the encapsulated waste.

The jet-grouting phase was accomplished with minimal dust spread and no rare-earth tracer spreadabove background levels. The application of the demolition grout, BRISTAR, failed to adequatelyfracture the waste as planned. Although the monolith was not fractured by the demolition grout, thestandard backhoe bucket with thumb attachment was successful in removing the monolith in the belowgrade orientation.

During this demonstration, it was shown that American Society of Testing and Materials (ASTM)Type-I Portland cement was jet groutable, the resultant monolith was free of voids, and there was areduction in dust spread during retrieval compared with the use of conventional mining techniques tocontrol dust. When performing retrieval with the overburden removed, a 90% dust removal wasachieved.

2.1.2 Subsurface Stabilization of Simulated Transuranic Pits and TrenchesDemonstration

In 1995, demonstration of two innovative subsurface stabilization technologies was performed atthe INEEL by the Landfill Stabilization Focus Area of the DOE Office of Technology Development(Loomis, Thompson, and Heiser 1995b). The first demonstration created a stabilization wall by jetgrouting Portland Type-I cement into the interior of a simulated buried waste pit. The wall allowed fornear-vertical digging in the waste pit when removing the hot spot, thereby reducing the amount ofmaterial excavated for hot-spot removal. The second demonstration created a monolith by jet grouting atwo-component acrylic polymer. The stabilized monolith was used for both hot-spot retrieval withenhanced contamination control and encapsulation for stabilization of buried waste. For the seconddemonstration, two different simulated pits were grouted with different formulations of the acrylicpolymer. The first was a hard durable material useful for long-term encapsulation, and the second was asofter, more easily retrievable material for interim storage and eventual retrieval conditions.

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The simulated test pits were constructed similar to the TRU pits and trenches in the SDA at theRWMC. A variety of waste disposal practices were simulated, including random dump and stackedorientations of the containers in shallow land burial. This demonstration involved several phases,including jet grouting, excavation/destructive examination, and stabilization evaluation. Test resultsshowed that jet-grouting emplacement of Portland cement resulted in a solid wall with no visible voidsand a high compressive strength.

For the second demonstration, two simulated buried waste pits were jet grouted. Interim storagefollowed by retrieval was demonstrated in one pit, and long-term encapsulation was demonstrated in theother. The polymer was an acrylic polymer from the 3M Company, Inc. consisting of two monomers(equal portions of Part A and Part B) with benzoyl peroxide and amine additives to start thepolymerization process. Two different formulations of the polymer were used: one to produce a harddurable materia] for long-term encapsulation, and the other to form a soft, resilient material for ease ofretrieval and enhanced contamination control during retrieval.

Excavation with a standard backhoe of the soft polymer pit showed an enhanced dust control overretrieval involving standard mining techniques. A destructive examination of the hard polymer pit using abackhoe showed that the acrylic polymer material resulted in a cured stabilized monolith with no voids.Coring the hard polymer monolith also demonstrated the solid nature of the pit. During destructiveexamination, it was discovered that the hard polymer was easily fractured with a standard backhoe, andthe pit could be removed in large cohesive chunks of soil/waste/polymer. Research to date shows thetechnology to be a functional, low-cost method for long-term in situ stabilization of various waste forms.The technology is extremely compatible with capping, hot-spot treatment and/or removal, and subsidencecontrol.

In summary, two different formulations of a two-component acrylic polymer grout were fieldtested by jet grouting a simulated buried waste site waste. One formulation resulted in a hard durablemonolith that was easily retrieved with little dust spread. The study expanded the list of grouts that weredemonstrated to be jet groutable.

2.1.3 Innovative Subsurface Stabilization Project

In 1996, the Innovative Subsurface Stabilization Project was a series of applied research tests tostabilize simulated buried waste sites with several types of grouting agents using jet-grouting techniques(Loomis, Zdinak, and Bishop 1996). The focus of this project was (a) evaluate the implementability ofvarious stabilization agents using jet-grouting methods; (b) evaluate the emplaced monolith developmentand intemal integrity by coring drilling and sampling, downhole video surveys, and destructiveexaminations; (c) perform field hydraulic conductivity testing of specially designed full-scalepermeameters; and (d) perform localized hydraulic conductivity testing (packer testing) in boreholesdri]led into the monolith.

During a field study, four innovative grouting materials and one commercially available grout ngmaterial were evaluated for use in creating monoliths at buried waste sites using jet grouting.

The four innovative materials included a proprietary water-based epoxy, an INEEL-developed two-component grout that resembles hematite when cured with soil, a molten low-temperature paraffin calledWaxFix TM, and a proprietary iron oxide cement-based grout called TECTTM. The commercial grout wasAmerican Petroleum Institute (API) Type-H cement. The materials were tested in specially designedCold Test Pits that simulated buried TRU waste at the INEEL

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In addition to the grouting studies, specially designed full-scale permeameters were constructed toperform mass balance hydraulic conductivity studies. A baseline ungrouted penneameter containedsimulated buried waste and soil, and a second identical permeameter was grouted with commercial-gradeAPI Type-H cement.

Both the TECT and WaxFix grouts were successfully grouted in a typical buried waste pit.Grouting of the TECT material was accomplished with minimal grout returns while still filling voids inthe pit. The WaxFix grouting operation resulted in copious grout returns but with excellent permeation ofungrouted soils. Both TECT and WaxFix resulted in a cohesive (stand-alone) monolith with essentiallyno voids. The TECT material was difficult to retrieve because the resultant monolith cures to a hardmaterial. The WaxFix monolith, while freestanding, was easily retrieved with a standard backhoe withminimal dust spread. Both of these materials were recommended for jet-grouting buried TRU waste sitesor radioactive-contaminated soil zones.

Also successfully grouted was the API Type-H cement in both a full-scale permeameter ofsimulated waste and a pit. The API Type-H cement formed a cohesive monolith following jet grouting,except in regions of high concentrations of sodium sulfate (used to simulate nitrate salts). Although jetgroutable, the API Type-H cement had a tendency to filter cake, causing plugged nozzles during injection.

The INEEL-developed hematite material could not be jet grouted because of "filter cakine of theslaked lime slurry. The proprietary epoxy material could not be jet grouted because part of the mixturewas too viscous to jet grout.

Use of a thrust block for secondary waste management worked well for controlling retums of theTECT grout. Modification of the thrust block for expansion to control grout returns may be required foruse with the WaxFix grout.

Hydraulic conductivity of INEEL-simulated buried TRU waste was measured at about 10E-5centimeters per second (cm/s). The hydraulic conductivity measurement of the permeameter grouted withAPI Type-H cement was inconclusive because saturated flow was not achieved in the field time available.Based on outflow data, the hydraulic conductivity values were approaching 10E-6 cm/s. The hydraulicconductivity of the grouted penneameter measured using packer tests was less than 10E-7 cm/s.

2.1.4 Acid Pit Stabilization Treatability Study

A CERCLA treatability study was performed in 1997 at the INEEL at a buried mixed waste sitecalled the Acid Pit. The Acid Pit is a contaminated soil zone located in the SDA at the RWMC. Themain contaminants of concern were mercury and minor amounts of radiological materials such as fissionproducts, uranium, and plutonium. The treatability study was an in situ stabilization of the targeted wastezone using jet-grouting techniques to create a monolith.

As part of the treatability study, tests of both nonradioactive (cold) and radioactive (hot) soils wereperformed and consisted of three testing phases: laboratory study, cold test demonstration, and Acid Pitstabilization. Previous tests were performed in test pits involving buried waste mixed and covered withsoil. The first phase was the selection of grout. The grout selection was based on mixing studies of AcidPit soil and five previously field tested grouts. The second phase was a demonstration field testing undersimulated conditions representing the Acid Pit. Information from this phase provided data concerning theoperational readiness of the technology before proceeding to the contaminated testing area at the Acid Pit.The last phase involved using the knowledge gained from previous phases and deploying the technologyat the Acid Pit.

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Field activities to evaluate the effectiveness of the technology included (a) temperaturemeasurements during curing, (b) destructive examination of the pits and field trials, (c) contaminationmonitoring, (d) geophysical evaluation of emplaced monoliths, and (e) sonic drilling techniques to collectsamples for analytical testing.

Overall, the treatability study demonstrated the viability of using jet grouting to stabilize acontaminated soil zone. The study showed that stabilizing a contaminated soil is considerably moredifficult than stabilizing buried debris and resulted in modification of grouting parameters and problemswith grout returns. However, even though the planned grouting sequence could not be successfullycompleted, cohesive monoliths were produced. Good correlation was seen between data collected fromthe cold test site and the Acid Pit. Based on examination of recovered core samples, geophysical datawere successful in imaging grouted and ungrouted regions (Loomis, Zdinak, and Jessmore 1998). Thetechnique for using high-pressure injection by jet grouting appears feasible for stabilizing contaminatedsoil sites if an appropriate stabilization material can be identified for the targeted contaminants.Contamination control measures that were implemented provided adequate protection to field workersand equipment and prevented the spread of contamination during grouting.

Based on data from these demonstrations, the technology of jet grouting buried waste sites toprovide stabilization and containment has been shown to be practicable using a variety of groutingmaterials. Implementation parameters developed from these grouting demonstrations will be used in thein situ grouting treatability study. Contamination control measures such as the thrust block and systemhardware have been proven effective at eliminating contaminant spread during jet-grouting and clean-outprocesses. Grout retums have been contained using the thrust block system.

2.2 Description of the Jet-Grout Technology

The in situ grouting process works by injecting a grout material selected for the specific applicationat high pressure and velocity into the buried waste site using a modified well-drilling apparatus. The highvelocity of the injected grout results in filled open spaces in the mixture of waste and soil. A thrust blockand related equipment control grout returned to the surface and contaminant spread.

In the first step, the drill stem is driven through the targeted contaminated zone using a jet-groutingdrill rig until a designated depth is reached. Then the drill string is systematically withdrawn in discretedistance intervals for discrete time intervals for each step while the high-pressure grout is forced throughthe injection nozzles into the soil/waste matrix. The action of grout injection causes violent mixing of thegrout with the soil/waste to produce a solid column of a waste, soil, and grout mixture. The monolith isformed by drilling and grouting multiple holes to produce a series of vertica] and overlapping groutcolumns. A schematic of the jet-grouting apparatus is shown in Figure 2-1.

The jet-grout equipment required by this operation includes-

• A jet-grouting/drill rig equipped with rotopercussion drilling capabilities

• A displacement pump with a maximum injection pressure of 10,000 psi and a flow rate of140 gal per minute

• A smaller transfer pump with hopper attachment to filter and screen the grout mixture fromthe grout source, often a concrete or tank truck, to the high-pressure pump

• Volume flow meters to measure incremental and total volume of injected grout

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Grout tankand mixer

Soil berm

Posltive displacementhigh pressure pump

Thrust block

HEPA boot

Drill stem shroud

HEPA system

injection hole(typically on 2 fttriangular pitch)

019196 0109

Figure 2-1. Jet-grouting apparatus.

• A thrust block to maintain spacing of grouting holes, provide a flat working surface, supportthe grouting/drill rig, and control grout returns

• Waste containment system to control/catch grout returns and prevent contaminant sprcad.

The drill system is equipped with programmable instrumentation to adjust and regulate thejet-grouting parameters such as mast movement and rotary head speed. Grout injcction pressure iscontrolled by thc pump operator. The grout injection intervals are coordinated between the driller andpump operator. The down-hole drill assembly consists of a high-pressure jet-sub with two 2.3 to3-mm-diameter nozzles positioned 180 degrees apart. The nozzles are nominally 6 in. from thc bottomtip of the drill bit.

2.2.1 Description of Contamination Control Measures

A number of contamination control measures are employed during the field jet-grout operation. Tocontrol contaminant exposure to workers and the grouting equipment, the jet-grouting apparatus isequipped with a high-efficiency particulate air (HEPA) filter system, a collapsible shroud covering thedrill stem, and a catch can for containment of excess grout materials. The catch cup is used to containexcess grout during drill stem transfer between grout holes. Blotter paper and a spill containment pan areplaced over each grout access hole to control minor drips during drill rig movement.

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Thrust block panels are placed over each test area to provide a level-working surface for thejet-grouting rig and to control excessive grout returns. The thrust blocks remain permanently in placeafter grout injection to act as a barrier to surface water infiltration. Thrust block panels are fabricatedfrom reinforced concrete and are used to form the working area by connecting the concrete panelstogether. The panels are constructed with holes so that the catch cup assembly and drill stem can beinserted through the thrust block. The access holes are nominally 5 in. in diameter and are equipped withneoprene material to wipe and clean the drill stem as it is extracted from the grouted hole. Access holesare spaced in a triangular pitch grid pattem 18 to 24 in. apart on centers depending on grout materialbeing utilized and site characteristics.

2.3 Grout Test Material Selection

Grout materials can be broken into two classes: those that affect the chemical properties of thegroundwater in the waste site and those that do not. Those grouts that do not affect the waste sitegroundwater would be chosen whenever the Eh and pH of the groundwater have the required (oracceptable) properties (pH of about eight and an oxidation potential equivalent to air) and/or maintain theproper characteristics to effectively control site hydraulic conductivity. Within the chemically activegrouts, several subcategories can be defined. There are those that do not affect oxidation potential (Eh),but affect pH. Grouts in this group can affect the pH moderately, e.g., pH of nine, while others maygenerate a pH in excess of ten. Still other grout materials affect both the Eh and pH of the groundwater.The grout materials selected for treatability study testing have representatives in the categories "noeffect," "moderate alkaline pH, no Eh affect" and "moderated alkaline pH affect and reducing Eh."

2.3.1 Grout Material Screening Process

The selection of the candidate grouts for the in situ grouting treatability study was restricted tofamilies of materials that had been field tested and shown to be implementable in simulated buried wastesimilar to the waste in the SDA. The grouts field tested and shown to be implementable includecandidates from three classes of materials: cementitious, acrylic polymer, and paraffin-based grouts.

The cementitious grouts included TECT, Portland Type-I cement, and API Type-El cement. Noneof these grouts will affect the Eh of the waste site groundwater. The pH of TECT is about 9 after set andcure, but the pH of Type I and Type H are usually greater than 10. SDA groundwater is oxidizing andcontains carbonate ion. These propethes together with the high pH from Type I and Type H wouldprobably enhance the tendency for uranium to be mobilized. Therefore, these two grouts were notconsidered further. The performance of TECT was very good in past INEEL studies. 1ECT was utilizedfor the INEEL SDA Acid Pit Project (Loomis et al. 1999). It consists of a hematite-pozzolanic,cementitious mixture. It was used to successfully stabilize low-level radioactive and mercurycontaminated soils. TECT was selected for treatability study evaluation.

Three additional cementitious materials were selected for evaluation in the bench andimplementability tests for long-term disposal. These include Salt Stone, Tank Stabilization Grout, andKrystal BondTM

Salt Stone was developed at the Savannah River Site to stabilize aqueous nitrate salt wastestreams and their radioactive contaminants. In addition to the nitrate salts, the grout wasspecifically designed to stabilize technetium and plutonium. The grout is composed of blastfumace slag, fly ash, and minor amounts of Portland cement. After set and cure, the groutwill produce a pH of about 9 and a reducing environment in the waste site groundwater(WSRC 1992 and 1994).

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2. Tank closure grout was developed at the Savannah River Site to stabilize waste remnants intanks. The grout formulation consists of ASTM Type-V Portland cement, blast furnace slag,and silica fume. It was specifically designed to immobilize uranium, plutonium, and otheractinide element contaminants. The bulk composition is similar to Salt Stone. After set andcure, it will have chemical properties similar to Salt Stone. The different materials in theformulation may produce different physical properties from Salt Stone, i.e., viscosity, watercontent, set time, porosity, strength, etc. (WSRC 1994).

3. Krystal Bone" is a proprietary magnesium silicate-based grout material. It was designed tochemically bind toxic metals. It has excellent wetting and permeation properties. It does notaffect the chemical environment of the waste site groundwater.

A second class of grout is the two-component acrylic polymer grout. Components of this materialare mildly toxic, and the mixture has a very offensive odor. It did not mix well with simulated organicsludge and, at $30 per gallon, was also very expensive. Acrylic polymer was not considered further fortreatability study application.

The third class is the paraffin-based grout. The proprietary grout, WaxFixTM was field tested at theINEEL in 1996 (Loomis et al. 1996a and 1996b). This material gave excellent field performance. Forconfinement during retrieval, the material was the best of those tested and resulted in an obvious dustreduction. The material is easily excavated and transported without contaminant release. It provideslubrication that may be desirable in postexcavation waste handling operations. It also adds significant Btucontent to the waste, which would be beneficial for waste incineration. It is the material selected forconfinement during retrieval testing.

Application of unmodified WaxFix to the SDA raises a potential criticality issue because paraffinis a neutron moderator. The treatability study will focus on determining whether boron can be added tothe WaxFix and if the modified material can be successfully applied using the jet-grout apparatus.Because the implementation and hydraulic properties of the paraffin-based grout are also excellent forlong-term application, WaxFix, if appropriately boron modified, was included in the long-term disposaltreatability study. WaxFix will not affect the Eh or pH of the waste site groundwater. The long-termstability of the wax material will depend on its resistance to microbial attack. A literature study of thelong-term stability of the wax material for long-term disposal application will be conducted and presentedin the Interim Report of this treatability study.

The performance of these materials in the bench and implementability tests will be evaluated(Section 4.1.1.3). Ranking of the grouts based on these evaluations will determine which grout will beused in the field study. The highest ranked grout will be field tested; the second will be a backup choice.

Two additional grout materials, a pumice/cement-based grout and a phosphate-based grout, will betested for implementability by their respective vendors for additional input into the RI/FS.

2.4 Verification Technology Description

Verification of the testing program will provide documented proof that the in situ groutingtreatment meets performance requirements. The performance goals include complete treatment of thesimulated-waste pit volume, determination of the chemical and physical properties of the grout, andverification of the grout application method to include control of grout returns and contamination spread.The confinement during retrieval program will also verify that the reduction in dust during retrieval is90% or more.

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During the in situ grouting operation, the implementation parameters will be measured. Theseinclude, but are not limited to, volume of grout injected, rate of grout emplacement, head rotationvelocity, grout viscosity, etc. Airbome dust will be measured as a function of time during theconfinement during retrieval in order to verify that the wax is performing at least as effectively as inearlier trials. Grout set temperature and time will be measured in situ. All of the data will be used toverify the grout injection process and the behavior of the grout during the set and cure period.

Following the set and cure period, hydraulic conductivity and field permeability tests will becarried out on the long-term disposal test site. The hydraulic conductivity will be verified by comparingthe data of hydraulic conductivity measurements of samples collected from the pit.

After hydraulic conductivity testing, the pit will be examined by systematic sample collection anddestructive examination. Results will verify that the target volume of waste has been treated and thatmonolith design has been achieved. Laboratory testing of the samples will verify that the physical andchemical properties of the field grout material meet performance goals to be described in detail in the TestPlan.

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3. TEST OBJECTIVES

Remedial alternatives developed during the OU 7-13/14 feasibility study, such as in situ grouting,will be evaluated against EPA-established criteria under CERCLA (EPA 1988). Information about in situgrouting for application at the SDA is currently insufficient. Therefore, this treatability study wasinitiated to address data gaps so that the in situ grouting technology could be considered during thefeasibility study altemative evaluation.

A number of performance issues identified previously in the Addendum to the Work Plan for theOperable Unit 7-13/14 Waste Area Group-7 Comprehensive Remedial Investigation/Feasibility Study(DOE-ID 1998) were used to help focus the test objectives presented in this work plan.

Based on the preliminary evaluations of these performance issues, critical and noncritical testobjectives have been identified for the in situ grouting treatability study. Critical objectives refer to theobjectives considered essential to the successful demonstration and evaluation of the system. Noncriticalobjectives are important but are not considered to be critical to the evaluation of in situ grouting as analternative in the OU 7-13/14 feasibility study, either because the information is not critical or enoughpreviously collected data are available that would provide some level of confidence in a performanceestimate for the feasibility study. If time or budget runs out, tests to support noncritical objectives couldbe scaled back or eliminated. Any changes to test objectives will be clearly documented in theTreatability Study Work Plan.

In accordance with the overall objective of the treatability study to provide sufficient data toevaluate the in situ grouting technology, the study will be considered successful if sufficient data arecollected to allow evaluation of the in situ grouting technology on the basis of criteria as required by EPAunder CERCLA. Test objectives relative to the CERCLA criteria are summarized below as critical ornoncritical objectives. The intended use of the data and how the objective relates to preliminaryremediation goals, if applicable, are described for each objective. The testing strategies to collectnecessary data addressing these test objectives are described in Section 4.

Two separate treatability studies will be conducted for remedial application at the SDA. The firstis in situ stabilization of waste and soil to allow safe long-term management of the materials. The secondis in place stabilization of the waste to increase safety and efficiency during retrieval and ex situ wastemanagement. Separate test objectives have been developed for each treatability study and are describedfor both of these potential applications in the following subsections.

3.1 In Situ Grouting for Long-Term Disposal

3.1.1 Critical Test Objectives

The critical test objectives for the long-term disposal application for the in situ grouting treatabilitystudy are listed below. Each objective is broken down into subsections of test requirements, objectivepurpose, proposed data usage, and relevant CERCLA criteria to be answered by the objective. Thecritical objectives are identified by number.

Test Objective 1—Estimate the Durability of the Grouted Waste Monolith

Test Requirements—Strontium carbonate will be added to dry cementitious grouts (0.1 wt%) priorto mixing. These formulations will be used in the bench and implementability tests. Samples will becollected from grouted waste forms (monoliths) to be analyzed by the Accelerated Leach Test forstrontium, calcium, silicon, and aluminum.

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Data Usage— Dissolution rates for the grout(s) tested will be calculated from the resultingAccelerated Leach Test data.

Purpose—Dissolution rates will be used to predict the half-life of the monoliths. This will beindicative of the ability of the monolith to resist degradation, maintain contaminant encapsulation, andcontrol contaminant solubility (buffering capacity). These results will be combined with the results ofother testing (e.g., hydraulic, chemical) and thermo-chemical data to support the risk assessment modelsfor the OU 7-13/14 feasibility study.

Relevant CERCLA Criteria—Overall protection of human health and the environment; compliancewith ARARs; long-term effectiveness; and reduction of toxicity, mobility, and volume.

Test Objective 2—Evaluate Hydraulic Properties of Grouted Waste Monoliths

Test Requirements—Bench hydraulic conductivity tests will be conducted on the grouted wastemonoliths. Other tests (e.g., porosity, tensile strength, shrinkage) will be performed on samples collectedfrom the monolith to assess hydraulic properties that could influence permeability.

Data Usage—Hydraulic conductivity data will be used to assess effects to the properties of thegrout as a result of high-pressure injection into the soil/waste matrix. Effects of the presence of varioustypes or forms of waste material included in the test pit also will be evaluated. Data will be used todetermine the ability of the monolith to eliminate, reduce, or cOntrol migration of target contaminants byreduction of permeability compared with current site conditions.

Purpose—Results from these tests will be used to determine the hydraulic conductivity of thegrouted soil/waste matrix. A reduction in the parameters due to grouting is an indication of a reducedinflux of water into the monolith.


Test Objective 3—Identify Grout Material to Support Monolith Application

Test Requirements—Several ratios of soil/waste matrix to grout mixtures will be used in the benchstudy to determine maximum matrix loading and grout compatibility with interferences. Physical andchemical properties of the matrix/grout monoliths will be compared with bench test results and used toassess grout performance.

Data Usage—The data will be used to rank grout formulations and select the ideal mixture for fieldtesting.

Purpose—To identify one or more preferred grouts for field testing. Results will be combined withthe other test results (e.g., hydraulic properties) to estimate longevity of the monolith to support the riskassessment model for the OU 7-13/14 feasibility study.

Relevant CERCLA Criteria—Implementability, overall protection of human health and theenvironment; compliance with ARARs; short-term effectiveness, long-term effectiveness; and reductionof toxicity, mobility, and volume.

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Test Objective 4—Evaluate Chemical Buffering Properties of the Grouted Waste Form

Test Requirements—Leachability of hazardous waste constituents (e.g., metals) are affected bytheir chemical environment, specifically pH and oxidation-reduction potential (e.g., redox potential orEh), which influence metal speciation and solubility. The Eh and pH of the grout formulations and thegrouted waste forms will be measured.

Data Usage—The Eh and pH will indicate the chemical environment of the monolith and thesolubility of contaminants. Contaminant solubility will then be used, along with other data (e.g.,permeability, hydraulic conductivity, etc.) generated from this study and chemical properties from theliterature review to model mobility and release rates of waste constituents from the grouted waste form.

Purpose—The purpose of the test is to predict the chemical behavior of waste components in thechemical environment controlled by the chemical properties of the grout. The grout materials can beselected specifically for their chemical buffering properties which can minimize the solubility of targetcontaminants by changing the oxidation-reduction potential and pH of the groundwater. The results willbe used to model contaminant release rates and mobility to support the risk assessment for theOU 7-13/14 feasibility study.


Test Objective 5—Evaluate the Physical Stabilization of the Waste Site to Control Subsidence

Test Requirements—Systematic samples from the monolith will be collected and tested forunconfined compressive strength.

Data Usage—Strength test data will be used to determine if the grouted waste forms will provide astable foundation for material placed upon it, including impermeable caps and cover material.

Purpose—At the SDA, undesirable collapse and subsidence of the soils into subsurface void spaceoccurs during wet weather conditions. Such subsidence is unacceptable for long-term site stabilizationbecause it affects the local hydraulic properties by causing ponding of surface water and the developmentof zones of high permeability into the waste.

Relevant CERCLA Criteria—Implementability and long-term effectiveness.

Test Objective 6—Evaluate INEEL Administrative Feasibility for In Situ Grouting ProcessImplementation

Test Requirements—During the Field Test, a qualitative assessment will be made of theadministrative feasibility of applying in situ grouting to buried waste sites containing mixed TRU waste atthe INEEL. Specific evaluations shall be made to determine the ease to obtain approval to perform thistype of testing, which requirements are needed to obtain such approval, and the degree of supportexpected from the site during in situ grouting processing. Information for the radioactive aspects of theadministrative feasibility of this technology will be accomplished from test findings during the treatabilitystudy for the in situ vitrification technology.

Data Usage—Resulting data and observations will assist in providing a more accurate estimate ofthe cost and administrative feasibility of implementing in situ grouting at the SDA.

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Purpose—The data are needed to properly estimate costs and administrative feasibility associatedwith implementing an in situ grouting remediation strategy at the INEEL. This information must beconsidered as part of the economic evaluation for in situ grouting implementation at the SDA.

Relevant CERCLA Criteria—Implementability and cost.

Test Objective 7—Determine Contaminant Release During In Situ Grouting

Test Requirements—Smear samples, high-volume air filters, solid samples of grout returns,personnel monitoring, and cleanout product samples will be taken during grout emplacement for the FieldTest. To simulate the radioactive component in the SDA pits, rare-earth tracer will be placed in thesimulated test pits. Sample media will be analyzed for particulate concentration, as well as theconcentrations of rare-earth tracer.

Data Usage—The data will be used to define the extent of the simulated contaminant/tracermigration during grouting and to assess the performance application of contamination control measures.

Purpose—An important operational issue that could affect the application of this technology at theSDA is the potential for contaminant releases during grout injection and system operations. The amountof contamination spread must be quantified to determine whether the advantages of the treatment processare offset by the contamination spread concems. Contamination control measures will be monitored toevaluate the effectiveness of the engineered system to provide adequate safety and to minimize potentialdelays and loss of equipment. Additionally, this information will be useful to define the degree ofdecontamination that will be required for in situ grouting equipment or portions of the equipment forapplication at the SDA.

Relevant CERCLA Criteria—Short-term effectiveness and implementability.

Test Objective 8—Evaluate the Field Unplementability of the Grout Emplacement Process forMonolith Design Application

Test Requirements—Information relative to emplacement of hardware designs, safety equipment,grouting procedures, materials mixing, and delivery logistics will be collected during grout emplacementfor the Field Tests. A combination of qualitative and quantitative data will be collected during and aftergrouting. A detailed examination of the grouted waste forms and monolith development will also beperformed to evaluate the monolith's quality and integrity.

Data Usage—The qualitative and quantitative data will be used to validate or invalidate theimplementability of the technology. After emplacement, both qualitative and quantitative examinationsof the monolith will be performed to assess product quality and effectiveness of the treatment.

Purpose—Measurements for grout emplacement will provide essential information for assessmentof operational and associated application difficulties that could be encountered during technologyapplication. Logistic issues associated with support systems will also be assessed for implementation ofthis technology. Reliability of the technology will be evaluated through quality control procedures andverified by destructive examination.

Relevant CERCLA Criteria—Implementability.

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Test Objective 9—Evaluate the Effects of Soil, Organic Sludge, and Nitrate Salt Waste Matrices onGrout Properties

Test Requirements—The interferences of soil, nitrate salt, and organic sludge concentrations mayadversely affect grout performance. This assessment will be performed on specially prepared groutsamples mixed at various loading concentrations of the simulated materials in bench testing.

Data Usage Test results and observation will assist with determining the waste loading tolerancefor the grout materials and waste matrix compatibility of the chosen grouts with contaminants expected atthe SDA.

Purpose—Nitrate salts and organics have been identified as specific waste matrices of potentialconcern at the SDA and have previously been shown to interfere with localized performance andmonolith development of some grout mixtures when present in high concentrations. It is anticipated thatin an SDA application the grout will be exposed to localized concentration ranges from 0 to 100% forthese primary waste matrices. Bench test samples with waste loadings of 0, 12, 25, 50, and 75% byweight for each of these matrices will be evaluated for comparative purposes, and to provide some datarelative to maximum waste loadings each grout candidate might tolerate. Experience has shown that suchwaste loadings above 75% result in a nonsolid improperly cured mixture for any grout product. Fieldtesting has been designed to allow for a thorough assessment of the preferred grout's performance underSDA conditions relative to these matrices (soil, organic sludges, nitrate salts) without the specified VOCs.

Relevant CERCLA Criteria—Implementability and short-term effectiveness.

3.1.2 Noncritical Objectives

The noncritical objectives for long-term disposal of the in situ grouting treatability study are listedbelow. Each objective is broken down into subsections of test requirements, objective purpose, proposeddata usage, and relevant CERCLA criteria to be answered by the objective. The noncritical objectives areidentified by letter.

Test Objective A—Determine the Concentration of Rare-Earth Tracers, and Nitrate Salt in theGrouted Waste Form

Test Requirements—Systematic samples of the grouted waste forms will be collected from themonolith after the completion of field hydraulic conductivity testing. Grout samples will be submitted foranalytical testing to determine concentrations of rare-earth tracers and nitrates.

Data Usage—Analytical results will define simulated contaminant concentrations contained in thegrouted matrix. Rare-earth tracer composition will be used to estimate the degree of actinidemixing/homogeneity expected from grout emplacement at the SDA. Field testing results will becompared with bench testing to determine contaminant distribution from high-pressure mixing.

Purpose—The evaluation of simulated contaminant distribution is needed to validate encapsulationof the waste forms. Information will also be used to evaluate the physical and chemical interactions ofthe grout with the simulated contaminants.

Relevant CERCL9 Criteria Overall protection of human health and the environment; compliancewith ARARs; long-term effectiveness; and reduction of toxicity, mobility, and volume.

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Test Objective B—Evaluate Effectiveness of Grout in Retaining VOCs

Test Requirements—Grouts have the potential to encapsulate and reduce releases of VOCs fromwaste. This quantitative test will measure the amount of targeted VOCs remaining in grout-stabilizedsimulated organic sludge samples for the various grout formulations at optimum viscosities in bench tests.The results will be compared with a baseline sample of simulated sludge allowed to diffuse in an openenvironment.

Data Usage—The resulting data will determine the extent of microencapsulation and its potentialto reduce risks from VOCs.

Purpose—VOCs are among the primary risk-drivers in the SDA. The grout may reduce or preventthe release of these VOCs from the waste and reduce potential risk. Results will be used to determinemigration/volatilization of organic compounds from the stabilized waste form and to support the riskassessment for the OU 7-13/14 feasibility study.

Relevant CERCLA Criteria—Long-term effectiveness and compliance with ARARs.

Test Objective C—Estimate the Volume, Type, and Expected Disposition of Secondary Waste

Test Requirements—Following grout emplacement for the Field Test, a qualitative determinationwill be made of the total volume and type of secondary waste that was generated. The secondary wastedetermination will then be used to group each waste type in terms of disposal options for future in situgrouting applications.

Data Usage—Results from the applicability assessment will improve the estimates of cost andimplementability associated with in situ grouting processing of buried waste at the SDA for theOU 7-13/14 feasibility study.

Purpose—The secondary waste determination will be used to estimate the total volume ofsecondary waste expected to be generated during actual remediation of an in situ grouting waste site.This estimate will be included in the applicability analysis section of the final report on the in situgrouting treatability study.

Relevant CERCLA Criteria—Implementability and cost.

Test Objective D—Determine the Time, Equipment, and Labor Requirements for Mobilization,Demobilization, and Operations

Test Requirements—Extensive monitoring and recording will be performed during the Field Testoperations to define the time, equipment, and labor requirements associated with mobilization,demobilization, and operation of the in situ grouting equipment. In addition, the amount of grout usedwill be tracked for costing the material. Economic evaluation of time and manpower requirements mustinclude any maintenance or equipment operations that will be performed.

Full-scale direct costs will be estimated based on information obtained after completion of the insitu grouting treatability study. Based on application assumptions derived from the field application,individual cost components will be estimated for deployment at the SDA. Site operational issues andverification requirements will also be considered for this cost estimate.

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Data Usage—Results from the applicability assessment will improve estimates of cost andschedule associated with in situ grouting processing of buried waste at the SDA for the OU 7-13/14feasibility study.

Purpose—The data will be used with data from previous in situ grouting research programs toproduce a cost assessment for technology deployment at the SDA. An applicability assessment sectionwill be included in the final report on the in situ grouting treatability study. The applicability assessmentwill estimate the cost associated with remediating an acre-size buried waste site at the SDA.

Relevant CERCLA Criteria—Cost.

3.2 Confinement During Retrieval

Critical Test Objectives 6 through 8 and Noncritical Test Objectives A, B, D, and E pertain to bothlong-term disposal and confinement during retrieval. Critical and noncritical test objectives specific toconfinement during retrieval are described below.

3.2.1 Unique Critical Objectives

The critical objectives for the confinement during retrieval application for in situ groutingtreatability study are listed below. Each objective is broken down into subsections of test requirements,objective purpose, proposed data usage, and relevant CERCLA criteria to be answered by the objective.The critical objectives are identified by number.

Test Objective 1—Evaluate the EtTects and Implementability of the Boron Additive on theProperties of the ParatTin-Based Grout

Test Requirements—Bench testing will be performed to determine the kind and amount of boroncompound that can be mixed with paraffin-based grout. A solution of boron/borate and glycerin will beadded to the molten paraffin to determine any effects on the physical characteristics of the grout and themaximum achievable boron concentration. Suspension and distribution of the boron in the paraffin willalso be studied.

Data Usage—Data will be used to determine the implementability of paraffin-based grout with aboron additive. It will also indicate if there is sufficient distribution throughout the grout to be effectiveas a neutron absorber. Test results will be used to determine the maximum concentration of boron thatcan be successfully added to confinement during retrieval (paraffin-based) grout with even distribution.

Purpose—The addition of paraffin to waste containing fissionable contaminants may increaseneutron moderation and the potential for criticality. Boron is commonly used at nuclear facilities toprevent criticality because of its capacity to absorb neutrons and prevent criticalities. To address thisconcern, the implementability of adding boron solution to the paraffin will be studied.

Relevant CERCLA Criteria—Implementability, overall protection of human health and theenvironment; compliance with ARARS; short-term effectiveness, long-term effectiveness; and reductionof toxicity, mobility, and volume.

Test Objective 2—Evaluate Suppression of Dust and Contamination Spread During Retrieval

Test Requirement—The primary target of using paraffin for the confinement during retrievaloption is the reduction of dust and associated alpha emission during excavation. The dust reduction may

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allow manned entry to the retrieval area in bubble-suits and/or the elimination of at least one level ofconfinement. During excavation, rare-earth tracers and aerosolized dust will be monitored at and aroundthe dig face. This will be conducted using personnel monitors to measure dust in the breathing zone ofthe workers and will include the use of high-volume filters.

During excavation, rare-earth tracers and aerosolized dust will be monitored at the dig face. Thiswill be conducted in the breathing zone of the worker and will include the use of high-volume filters.

Data Usage—The resulting data will assist in providing a determination of the level of dustsuppression and contaminant spread during excavation/retrieval of the grouted waste forms.

Purpose—Emission of particulates will be evaluated during emplacement of the paraffin-basedgrout and excavation/retrieval of the monolith. The confinement during retrieval grout is expected toreduce airbome mobility by inhibiting the release of particulates during retrieval.

Relevant CERCLA Criteria—ARARs, overall protection of human health and the environment,short-term effectiveness, and reduction of toxicity, mobility, and volume through treatment.

3.2.2 Unique Noncritical Objectives for In Situ Grouting Confinement During Retrieval

The unique noncritical objectives for confinement during retrieval of the in situ groutingtreatability study are listed below. Each objective is broken down into subsections of test requirements,objective purpose, proposed data usage, and relevant CERCLA criteria to be answered by the objective.The noncritical objectives are identified by letter.

Test Objective A—Evaluation of the Btu Value of the Retrieved Grout Waste Form

Test Requirements—Monolith samples will be tested for Btu content during the bench and fieldtesting.

Data Usage—Test results will assist with the determination of Btu increase of the waste matrixwith addition of paraffin.

Purpose—The increase in Btu content due to the addition of paraffin or other polymeric grout tothe waste matrix will be used to evaluate potential ex situ treatment options, such as incineration of therecovered waste.

Relevant CERCLA Criteria—Implementability.

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4. EVALUATION OF TECHNOLOGY

The purpose of this section is to provide a description of the testing procedures required to supporttest objectives and fill data gaps. From the research and operating experience gained to date, severalissues associated with in situ grouting's effectiveness and implementability in the buried wasteenvironment in the SDA will be assessed. Performance issues were identified during previous treatabilitystudies (Loomis et al. 1995, Loomis et al. 1996, Loomis et al. 1999) and are included in the OU 7-13/14Addendum to the Work Plan (DOE-1D 1998). The testing strategy for this treatability study has beendesigned to resolve many of the issues that have been identified for in situ grouting of buried TRUwastes. For evaluation of the in situ grouting technology, two separate testing campaigns will beconducted for remedial application at the SDA. The first is in situ stabilization of waste and soil to allowsafe long-term management of the materials, referred to as long-term disposal. The second is in-placestabilization of the waste to increase safety and efficiency during retrieval and ex situ waste management,referred to as confinement during retrieval. The purpose of this treatability study is to provide the dataneeded for the risk assessment and detailed analysis of alternatives of the OU 7-13/14 feasibility study.This study will be performed in a systematic fashion to ensure that data generated can support theobjectives of the treatability study. This section describes the technology testing procedures for bothlong-term disposal and confinement during retrieval. The study involves both bench and field tests.Figure 4-1 shows a schematic of the proposed testing.

4.1 In Situ Grouting for Long-Term Disposal

The testing strategy for the long-term disposal for in situ grouting will involve three phases oftesting:

• Bench testing

• Implementability testing

• Field testing.

GroutVendorTesting

BenchTesting

PriorDeveloprnental

Testing

ImplementationFeasibilityTesting

Disposal Option

implementationFeasibilityTesting

Field TestingSimulatedPit Grouting

Field TestingDestructiveExamination/Hydraulic

ConductivityMeasurements

Collationof Data

Purpose: Choose grouts for if souse!

and retrieval option.

Field TestingSimulated

Pit Grouting

Field TestinqRetrieval

Dernonstration

Retrieval Option

GZ99 0159

Figure 4-1. Overall schematic of in situ grout technology evaluation testing.

RS!FS

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Bench testing will involve the mixing of the candidate grout materials to provide physical andchemical data of grout properties to select materials for implementability and field testing. Theimplementability testing involves limited field testing of acceptable grout materials to provide significantinformation concerning the injection and monolith development properties. Information from these twophases will feed into the field testing phase. This phase will involve field testing at an established cleannonradiological and nonhazardous test site that simulates conditions at the SDA.

Grouts chosen for this study are based on their low viscosity and compatibility with(a) conventional jet-grouting techniques; (b) environment and geotechnical characteristics of the SDAsoil, and (c) buried waste contaminants and chemistry. Grouts selected for long-term disposal are:

• TECTTM

• WaxFix TM

• Salt Stone

• Krystal BondTM

• Tank Closure Reducing Grout

• Ultrafine grout (U.S. Grout)b

• Enviroprep (American Minerals).'

Viscosity is an important property that needs consideration prior to jet-grouting. The importance ofthis property is two-fold. A relatively low-viscosity grout material is required since jet-grouted materialsare pumped, and then injected through tiny nozzle orifices (2-5 mm) at high pressures into thesurrounding soil/waste medium. Secondly, penetration depth of the grouts into soil waste formationsdepends on both material viscosity and density. From previous studies, groutable mixtures range up to7 minutes, as measured through a funnel viscometer. Viscosity is directly related to water concentrationin the mixture. Based on vendor specifications, the grout must display less than 7 minutes in a funnelviscosity test. Viscosity will be measured using a funnel viscometer according to the API ProcedureRP-13B-1, "Recommended Practice Standard Procedure for Testing Drilling Fluids." Fluid density willbe measured according to ASTM D4380-84 (Reapproved 1993), "Standard Test Method for Density ofBentonitic Slurries."

A discussion of these grout materials is presented in Section 2.3.

Testing phases for long-term disposal are discussed in more detail in the following subsections.

4.1.1 Bench Testing

Important criteria in the selection of viable candidates for in situ stabilization are grout materialproperties relative to buried waste matrix and soil loading compatibility. Therefore, bench testing willinvolve characterization of the grout mixtures to determine matrix compatibility and physical/chemicalperformance. Technical support for this phase will be provided by an offsite laboratory. Bench testingwill consist of three tasks:

b. The vendor/developer of this grout product has been provided with treatability study "bench testing protocol." The vendor isresponsible for conducting testing and supplying data to allow for evaluation of this product within the bench testing decision-making matrix outlined in the test plan.

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1. Screening testing for interferences

2. Physical and chemical characterization of grouts

3. Grout evaluation and selection for field study.

The following subsections present a more detailed discussion of the testing program for the benchstudy.

4.1.1.1 Screen Testing for Interferences. Experience has demonstrated that a small amount ofcertain interferences can significantly reduce the physical and containment characteristics of the monolith(Loomis et al. 1996). The presence of interferences such as volatile organic chemicals, nitrate salts, andsoil in the waste material may slow (or sometimes stop) grout setting and curing reactions. Samples willbe prepared to evaluate response of the grout with the addition of simulated interferences. In addition toexamining the effects of interferences, this initial screening step entails evaluation of curing ortemperature problems that may preclude the use of grout material.

Sample Preparation—Neat grout will first be prepared according to the mix formulas supplied bythe vendor or as specified in the literature. A sample set will be prepared for each grout withinterferences at 0, 12, 25, 50, and 75% by weight. The samples will be allowed to cure until settemperature equilibrium is attained, or 14 days have elapsed, whichever is less. Discussion of mixingformulation of the various samples follows:

Grout/Organic Sludge Mixture—Based on the Interim Risk Assessment for WAG 7 (Beckeret al. 1998), the source of nearly all of the volatile organic contaminants of potential concem in the SDAis the Series-743 organic sludge drums from the Rocky Flats Plant. For this reason, plans for the benchtest are to mix a slug of simulated Series-743 waste with each of the grouts using the same recipe used inpreparing the original Series-743 organic sludge (minus the actinide elements). The recipe for Series-743sludge preparation is as follows:

Calcium silicate 4,120 g

Carbon tetrachloride 2,680 mL

Oil-Dri 620 g

Tetrachloroethylene (PCE) 740 mL

Texaco Regal Oil, R&O 68 5,130 mL

Trichloroethylene (TCE) 740 mL

Trichloroethane (TCA) 1030 mL

The organic sludge recipe includes both hazardous halogenated hydrocarbons (i.e., carbontetrachloride), PCE, and TCE, classified as characteristic waste under the Resource Conservation andRecovery Act (RCRA). The Series-743 sludge simulant will be prepared in a manner that minimizesvolatilization during sample preparation. The sludge will be mixed into the grout at waste loadings of 0,12, 25, 50, and 75% by mass. These mixing concentrations were selected to correlate with varyingconcentrations in the buried SDA waste and to assess the effectiveness of in situ grouting under thesevarious waste loading conditions.

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Grout/Nitrate Salt Mixture—Test specimens will be prepared mixing the grouts with variousconcentrations of nitrate salt simulant. Simulations of nitrate salts will be prepared according toSeries-745 Stimulant, using 67 wt% sodium nitrate and 33 wt% potassium nitrate. Test specimens will beprepared at waste loading of 0, 12, 25, 50, and 75% by mass. These mixing concentrations were selectedto correlate to varying concentrations in the buried SDA waste and to assess the effectiveness of in situgrouting under these various waste loading conditions.

Grout/Soil—Test specimens will be prepared with grout/INEEL soil mixtures at soil to groutweight percent loadings of 0, 12, 25, 50, and 75%. These loadings represent a variety of soil/groutloadings that may result from the planned grouting operations.

Screening Examination—After sample preparation, quantitative measurements of compressivestrength and qualitative examinations will be made of each test sample to evaluate short-term effects dueto waste loading or water. Samples will be visually examined for defects such as:

• Cracking and fracturing

• Set retardation (e.g., no hardening or impeded hardening)

• Incomplete mixing (i.e., component separation)

• Swelling and disintegration.

Compressive strength will be measured using ASTM-C-3996 methods on all of the neat groutsamples and samples of grout with interferences. For these samples it will be determined what the highestpercent is by weight loading for each of the three interferences to achieve 50 psi. to here:

Grout mixtures displaying less than 50 psi compressive strength or obvious physical defects (e.g.,curing/setting problems), as listed above, will be eliminated from further physical and chemical testing.From this series of tests, data will also be acquired concerning maximum interference concentrationtolerance and will determine the maximum amount of contamination loading required to still produce ahigh-quality grout/waste mixture. It is expected from this series of tests to develop a short list ofacceptable grout mixtures for further characterization testing.

Another screening evaluation will be the temperature of set. The heat of hydration for grouts is anexothermic reaction that can emit a large amount of heat. A maximum set temperature for an acceptablegrout of less than 100°C is required. This specification is a safety requirement and is included in order toavoid the possibility of steam explosions during emplacement of a very fast-reacting exothermic material.Grouts that cure above 100°C will not be tested further. Temperature data will also be used duringranking and selection of grout materials for field testing. Low cure temperatures are desirable formaximum strength and minimum shrinkage.

For measuring cure temperature, sensors will be inserted into a subset sample of each grout mixtureafter initial preparation. A portable data logger will be attached to the sensors and used to measure andrecord in situ temperatures. Temperature recording frequency will be approximately every 20 minutes forthe first week of observation. The frequency may be reduced as the curing process progresses andequilibrium is approached. The time indexes will also be logged for the temperature measurements. Thetemperature measurements will be actuated to ± 1°F. The time measurements will be every 5 minutes.

4.1.1.2 Physical and Chemical Characterization. Physical and chemical tests were designedto evaluate grouts through a series of standard tests (Table 4-1). Test data will be used to rank the grout.

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Table 4-1. In situ grouting for long-term disposal bench physical and chemical testing requirements.

Sample Set Number

Test Test Method 1 2 3 4PerformanceRequirement

Hydraulic control

Implementability

Chemical buffering

Grout dissolution

Effects of grout onencapsulation on VOCrelease

Hydraulic conductivity

Porosity

Shrinkage

Tensile strength

Compressive strength

Density

Free water

Oxidation-reduction potential

Hydrogen ion activity

Accelerated leach test

VOC concentration instabilized samples

ASTM-D-5084-90

ASTM C-642-90

ASTM C-827-87

ASTM C-496-90

ASTM C-39-96ASTM D-695-91

Instrumentspecifications

Qualitativemeasurement

ASTM D-1498-76

ASTM D-1293-84

ASTM C-1308-95

SW-846Method 8260

X X X

X X X

X X X

- x- x

X X X X

X

Mixtures that display the highest interference loading and maintain compressive strength of 50 psi(USEPA OSWER Directive No. 9347.00-2A) will be included in physical and characterization testingalong with neat grout samples. Baseline data of specific grout properties will be obtained. Samples ofcompatible grout mixtures will be prepared according to mix formulas supplied by the vendor or specifiedin the literature. As part of the sample preparation process, fluid density and viscosity will be measured.Viscosity will be measured using a funnel viscometer according to the API Procedure RP-13B-1,"Recommended Practice Standard Procedure for Testing Drilling Fluids." Fluid density will be measuredaccording to ASTM D4380-84 (Reapproved 1993), "Standard Test Method for Density of BentoniticSlurries." Each of the grout mixtures will be mixed and molded in cylindrical nonpolyvinyl chloridepipe. All samples will be cured for 30 days and then removed from their molds. Baseline mass anddimensional data will be recorded, followed by immediate storage in a 100% humid environment. In allcases, samples will be placed in 100% humidity for a minimum conditioning period of 4 days.

Four sample sets will be prepared for characterization testing, Sample Sets 1, 2, and 3 will beprepared according to the maximum tolerance concentrations for nitrate salt, organic sludge, and soil,respectively, as determined during the screening test. Sample Set 4 will be prepared by adding 0.1 wt%.strontium carbonate (SrCO3) and 0.1 wt% potassium nitrate to grout and is considered a neat groutsample. For each sample set, grout properties will be investigated through a series of tests listed inTable 4-1, which include:

Hydraulic Conductivity—Hydraulic conductivity will be measured according to ASTM-D-5084-90. This parameter is important when determining migration of surface water through a monolith.

Porosity—The porosity is a measure of the interstitial space and is expressed quantitatively as therelationship between the volumes in the grout material occupied by solids and nonsolid. Porosity is

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directly related to hydraulic conductivity. Porosity will be measured according to ASTM C-642-90,"Standard Test Method for Specific Gravity, Absorption, and Voids in Hardened Concrete."

Shrinkage—Shrinkage cracks may occur as a result of excess water in the grout or the temperaturerise during grout curing. Shrinkage will be measured according to ASTM C-827-87, "Standard TestMethod for Change in Height at Early Ages of Cylindrical Specimens from Cementitious Mixtures."This test provides information on volume changes taking place in cementitious mixtures between the timejust after mixing and the time of hardening.

Tensile Strength—Tensile strength is a measurement of a material's ability to withstand loadsapplied in tension and indicates resistance of the stabilized waste to cracking due to shrinkage orsettlement of the underlying fill. Tensile strength (splitting strength) will be measured according toASTM C-496-90, "Standard Test Method for Splitting Tensile Strength of Cylindrical ConcreteSpecimens."

Compressive Strength—Strength test values indicate how well a material will hold up undermechanic& stresses created by overburden. In addition to the Nuclear Regulatory Commission TechnicalPosition, the EPA considers a stabilization/solidification material with a strength of 50 psi to havesatisfactory unconfined compressive strength (USEPA OSWER Directive No. 9347.00-2A). Thisminimum guideline of 50 psi has been suggested to provide a stable foundation for material placed uponit, including impermeable caps and cover material. Usually, the compressive strength of a jet-groutedencapsulated waste/soil product would not be an important parameter to test because of low overburdenforces present. The nature of the test makes it most useful when comparative results on the effects oftesting (specimen integrity) between grout/waste products are required. Therefore, the compressivestrength values reported will be used as an indicator of the loss of integrity when simulated waste ismixed with grout. Except for WaxFix, compressive strength measurements will be measured followingASTM C-39-96, "Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens."The test specimens for WaxFix will be compression tested according to ASTM D-695-91, "Standard TestMethod for Compressive Properties of Rigid Plastic."

Density—Density tests will be used to determine weight-to-volume relationships of materials.Cured grout densities will be calculated as a means of comparing variations in waste loading amongspecimens. Bulk density is also related to calculation of porosity. Density measurements will bemeasured using a Quantachrome Multipycnometer Model MVP-1 to measure the actual volume and aMettler electronic balance to weigh the sample. The multipycnometer measures the true volume of solidmaterial using Archimedes' principle of fluid displacement to determine volume. The instrument uses aninert gas (helium) as the displacement fluid that is capable of penetrating fine pore spaces.

Free Water—Free (bleed) water is the amount of excess water that floats to the surface of a groutduring curing. This is a qualitative measurement and will be based on the volume of water that formsafter preparing and curing the sample. The production of free water is an important consideration forsecondary waste generation and migration of contaminants during grout emplacement.

Oxidation/Reduction Potential (Eh ) and Hydrogen Ion Activity (pH)—Leachability of hazardousconstituents (e.g., metals) may be governed by the pH and Eh . Evaluation of these properties isimportant for determining if the desired chemical effects are present to chemically buffer the targetcontaminants. The redox potential and pH will be measured by EPA Method SW-9045.

Accelerated Leach Test The accelerated leach test is a critical test that will provide information ofthe chemical stability and diffusion information conceming grout components. This test will be used toestimate the dissolution rate of the grout waste form. Except for WaxFix, each sample will be tested to

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measure the release of strontium, calcium, silicon, and aluminum from the grout matrix. The acceleratedleach test data may be used to predict final grout form long-term performance. Samples will be testedaccording to ASTM C-1308-95, "Standard Test Method for Accelerated Leach Test for DiffusiveReleases from Solidified Waste and a Computer Program to Model Diffusive, Fractional Leaching fromCylindrical Waste Forms." A Varian Liberty 100 inductively coupled plasma spectrophotometer will beused to determine the strontium, calcium, silicon, and aluminum concentrations. Results of the analyseswill be evaluated using the Accelerated Leach Test computer program that will calculate the incrementalfraction leached, cumulative fraction leached, diffusion coefficient that best fits the leaching data, andvalue that describes the goodness-of-fit between the data and diffusion model results.

VOC Microencapsulation—Bench tests of VOCs remaining in grout-stabilized simulated organicsludge will provide information on the effectiveness of microencapsulation in decreasing the release rateof VOCs from the SDA. This test will determine the relative effectiveness of grouts, at their optimumviscosity, in stabilizing VOCs. Samples of simulated organic sludge stabilized with grout will beanalyzed for VOC content according to EPA SW-846 Technique 8260. A Gas Chromatograph-MassSpectroscopy (GC-MS) will be used to determine VOC levels following extraction from the sample usingpurge and trap techniques. Results of the test will be evaluated by comparing the amount of eachconstituent retained in the grouts to the amount retained by baseline samples of untreated sludge. Thisdata will not be considered in the grout selection process.

Durability of Paraffin-Based Grout—Expected durability of paraffin-based grouts will beevaluated in a white paper based on published results from previous studies. The primary factorsinfluencing the durability of paraffin in the environment over time are biological degradation withcontributing factors including temperature; available moisture, nitrate, phosphate, and potassium in thewaste form; composition of the paraffin (especially branching frequency and configuration); thickness ofthe paraffin coating; concentration and availability of oxygen, nitrate, sulfate, and other oxidizing agents;and presence and concentrations of compounds that inhibit bacterial growth (other hydrocarbons, toxicmetals, etc.). Results of a study will be included in the treatability study interim report. Data will be usedin the grout selection process for long-term durability. The report will present expected durability ofparaffin-based grout in the SDA, effects of the various identified factors on the expected rate, anduncertainties in establishing the rate. Sources for studies of degradation rates for paraffin degradationinclude laboratory studies of hydrocarbon degradation, controlled field experiments, and uncontrolledfield experiments.

4.1.1.3 Evaluation and Selection of Grout Materials for Implementability Testing. Alimited list of grout candidates will be selected from the bench testing. Table 4-2 lists the performancerequirements and acceptance criteria developed to evaluate the grouts.

A comparative analysis of criteria will be conducted to consider grouts for the field implementationstudy. If grouts have similar properties, then material cost will become a deciding factor, with lowestmaterial costs ranked highest. A per-gallon cost will be used for this analysis. Information will beobtained either from the material supplier or literature research. At a minimum, at least two grouts will beretained for the field implementability study with preferred grouts exhibiting the following characteristics:

• Resistant to environmental degradation

• Highly flowable

• Minimal shrinkage

• Minimal hydraulic conductivity

4-7

Table 4-2. Grout performance requirements and acceptance criteria.'

Priority PerformanceLevel Requirement

1 Hydraulic control

Grout dissolution

2 lmplementability

3 Chemicalbuffering

Measurable Property

PorosityTensile strengthShrinkage



Free waterDensityCompressive strength

Oxidation-reductionpotential/hydrogen ion activity

a. Performance factors are ranked fmm highest to lowest.

• Minimal porosity

• Maximum tensile and compressive strength

• Minimal free water

• Minimal curing temperature

• Maximum waste loading tolerance

• Optimal reducing and alkal ne conditions

• Lowest cost.

4.1.2 lmplementability Testing

Performance Criteria

Porosity reductionHigh strengthMinimal shrinkage

Reduction in permeability

Resistant to degradation

Minimal free water productionMinimal changes with waste loadingHigh strength

Optimal reducing/alkaline conditions

The purpose of implementability testing is to demonstrate the injectability of the selected groutformulations. A limited series of field trials will be performed to evaluate the jet-grouting application ofchosen grouts exhibiting ideal physical and chemical properties. This testing will provide essentialinformation concerning the operational aspects and column development properties of chosen groutmaterials.

This testing will be conducted at a vendor site with INEEL soil. Major equipment involved withthis operation will include:

• A jet-grouting/drill system equipped with rotopercussion capabilities

• A positive displacement pump with a maximum injection pressure of 10,000 psi and flow rateof 140 gal per minute

• A small batch mixing system

4-8

• A smaller transfer pump with hopper attachment

• Flow totalizer meters to measure volume of injected grout.

Initial preparation tasks will include construction of a test area similar to disturbed soil conditionsexpected at the SDA. INEEL soil will be provided for testing. Test area boundaries will be properlyidentified and field trial stations marked. Pits will be constructed next to each field trial station for thecollection and measuring of grout retums.

Grout mixing will occur onsite. Batch samples will be collected directly from the mixer beforegrouting is initiated and tested for viscosity and density as previously specified.

After material testing, the jet-grouting rig will be positioned for grouting of the field trials. Basicprocedures established during the Acid Pit Stabilization Treatability Study (Loomis et al. 1999) will befollowed. All grouting will be performed at two revolutions per step, at a step distance of 5 cm (1.97 in.)per step and a step rate of 6 seconds per step. Injection pressure is planned for 6,000 psi. The basicinjection process is as follows:

• Position jet-grouting apparatus drill string over field trial station

• Drill to 9 ft below ground surface

• Commence high-pressure injection and retract drill stem according to specified parameters to adepth of 3 ft below ground surface

• Discontinue high-pressure pumping

• Raise drill stem

• Move to next hole and repeat the procedure.

Three field trials will be emplaced for each grout. During the grouting process, field observationswill be made to determine if the grout material is pumpable and any operational problems occur duringthe emplacement process. Observations will focus on (a) filter caking properties of the material;(b) mixing problems such as excessive air entrainment, suspended solids, and material separation;(c) equipment fouling and residual build-up inside pumping equipment; and (d) other unusual operationoccurrences. The volume of grout returns produced during the emplacement will be qualitativelymeasured by routing the returns into a collection pit and manually removing the material with a 5-galbucket.

After emplacement, a sensor will be inserted into a field trial from each successfully emplacedgrout material and curing temperature will be measured. A portable data Iogger will be attached to thetemperature sensors and used to measure and record in situ temperatures. Temperature recordingfrequency will be approximately every 20 minutes for the first week of observation. The frequency maybe reduced as the curing process progresses and equilibrium is approached. The time indexes will also belogged for the temperature measurements. The temperature measurements will be actuated to ± 1°F. Thetime measurements will be every 5 minutes. These measurements will be compared with the benchtesting to evaluate effects of field emplacement.

Field trials will be allowed to reach a set, normally within 5 days and then exposed forexamination. Field trials will be excavated using a backhoe. The first step is excavation to the top of the

4-9

column and examination of the column for proper setting and column development. Once isolated, thefield material will be further exposed by removing incremental sections. Each exposed excavation facewill be evaluated, and detailed field notes and photographs will be taken. Detailed measurements of thenominal dimensions of the grout columns will be recorded Internal portions of all field trials will beinspected for completeness of mixing and grout permeation.

One grout material will be selected from this study for use in the field testing. The grout selectedwill (a) be pumpable with minimal operational problems, (b) have optimal column development (acombination of maximum column diameter with low percentage of soil inclusions), and (c) returnminimal grout.

4.1.3 Field Testing

The primary purpose of the field testing is to evaluate the implementability and effectiveness of thetechnology at a field testing arrangement that simulates the types of conditions expected in the SDA. Thefield testing will include the following three tasks:

1. Construction of a specially designed simulated waste pit (or test area preparation)

2. Grouting of a simulated waste pit with the final selected grout mixture (grout emplacement)

3. Excavation and dismantling of the grouted pit to examine and sample the resulting monolith(post grouting evaluation).

These tasks are discussed in more detail in the following subsections.

4.1.3.1 Task 1: Test Area Preparation.

4.1.3.1.1 Waste Pit Construction—Initial preparation tasks for the field demonstrationwill include surveying the site and constructing a large-scale pit. The test area will be constructed at theCold Test Pit area. It will simulate statistically average conditions for the SDA and closely representsimilar soil types, mineralogy, and permeability and waste deposition.

4.1.3.1.2 Simulated Waste Preparation—A combination of SDA wide waste volumes,and specific details of Pit 6 at the SDA were used as a model for defining the simulated waste containervolumes and waste material. Pit 6 was used as a model primarily because the average depth of buriedwaste is only nominally 8 ft, simplifying the retrieval process for the treatability study.

Table 4-3 shows the SDA wide volume fraction of buried waste broken down into majorcategories: combustibles, organic sludges, inorganic sludges, nitrate sludges, metal, concrete, andasphalt. For example, on a volume basis approximately 53% of the volume of waste in the SDA iscombustibles including cloth, paper, plastics, and wood. Table 4-4 shows that in Pit 6, the waste volumeapproximately equals 50% of the excavated volume and that there were 46% drummed waste (55-galdrums), 33% boxed (4 x 4 x 8 ft) and 21% material in cardboard boxes (combustible material). UsingTables 4-3 and 4-4 and simulated grid dimensions of 14 x 14 x 8 ft deep resulted in using two 4 x 4 x 8 ftboxes, forty-nine 55-gal drums and fourteen 2 x 2 x 3 ft polyethylene sacks as shown in Table 4-5. Metaldebris including plate steel, tubing, and scrap metal will be hand placed in two of the boxes along withconcrete, asphalt, and wood. There will be approximately 38% metal, 37% concrete/asphalt, and 25%wood in the boxes. Of the 49 drums 25 will contain combustibles including cloth, paper, wood, andplastic; 13 will contain inorganic sludges; six will contain organic sludges; and five will contain nitratesalts. Fourteen sacks will be filled with cloth and paper. In each of the containers (except nitrate drums)will be placed a rare earth tracer to be used in contamination spread determination during operations.

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Table 4-3. Volume fractions of buried TRU waste (SDA-wide).

Waste Type Volume

(m3)

Fraction ofTotal

Organics 3,120 0.059

Nitrates 2,250 0.043

Inorganic 6,480 0.124

Bricks/concrete 6,120 0.117

Metal 6,320 0.121

Combustibles 27,660 0.536

Total 52,092 1.000

Table 4-4. Pit 6 waste/soil volumes.

Excavated volume:

Soil volume:

Waste volume:a

Drums 102,272 ft3 46%Boxes 73,918 ft3 33%Cardboard debris 47,708 ft3 21%

100%

a. Waste volume comprised of drums, boxes, cardboard debris.

447,515 ft3

223,617 fta

223,898 ft3

Table 4-5. Simulated waste packages for the disposal pit.

Waste Container Type Number Composition'

Cardboard boxes 2 Metal debris (1/8 in. plate steel, tubing, piping, scrap metal), concrete/asphalt(4 x 4 x 8 ft) chunks (6-in. size) pulverized wood.

Metal 38%, concrete/asphalt 37%, pulverized wood 25%

Drums (55 gal)

Cardboard 25 Combustibles (cloth, paper, wood)

Cardboard 13 Inorganics (30 gal water; 139 lbm soil; 40 lbm dry Portland; 36 lbm NaNO3)

Cardboard 3 Organic (30 gal of Texaco Regal Oil; 100 lbm mirco cell-E;Metal 3 35 lbm kitty liter)

Cardboard 3 Nitrates (granular: 60 wt% Nallo3; 30 wt% KNO3; 5 wt% Na2Sa4,Metal 2 5 wt% NaCI

Sacks (2 x 2 x 3 ft) 14 Cloth, paper

(polyethylene)

a. Containers will be numbered and labeled (combustibles, inorganics, organics, nitrates). Waste packages will contain varying amounts of theterbium oxide (Tb407) tracer in the following quantities: boxes-400 g; combustible drums—I00 g; inorganic drums-200 g; organicdrums-50 g; nitrate dmms—none; all sacks-100 g. The tracer is a fine powder with a particle size in the 3 micron size distribution.

4-11

Table 4-5 gives the simulated waste composition and rare earth tracer concentration. Each drum and boxwill include a 4 mil polyethylene sack liner.

The simulated waste containers will be placed in the test pit in a random orientation except for afew specific containers. Figure 4-2 shows the general design features of the disposal pit constructionincluding a 2 ft compacted soil underburden, a 3 ft overburden, and standard thrust block approximately17 in. thick with a 12-in. space for grout retums. Figure 4-2 shows that several drums and boxes havespecial orientation to facilitate postgrouting hydraulic conductivity testing. Figure 4-3 shows a plan viewfor the orientation of a nitrate drum, an organic drum, and two boxes. The 25 combustible drums,13 inorganic drums, and 14 sacks will be randomly orientated but uniformly distributed among the fourquadrants shown in Figure 4-3. There is one special 3 x 4 ft deep region (shown in Figure 4-3), where nonitrate or organic drums will be placed. One of the remaining four nitrate drums will be placed randomlyin each of the four quadrants. In addition, of the remaining five organic drums, one each will be placed inquadrants one, two, and three, and two drums will be placed in quadrant four. Although the generaldesign of the pit is a random dump, a berm build-up method will be employed in which the pit will bebuilt from the bottom up using a berm around the outside dimensions of the pit. This will allowplacement of the specially oriented nitrate and organic drum. The exact center of these special drums willbe surveyed and the thrust block will be placed such that one of the drill holes will be located in an areawhere an exact penetration of the drums can occur. This is important for postgrouting hydraulicconductivity testing discussed later.

During construction of the pit, a record of where each drum and box was placed will be kept on adiagram. In addition, an extensive photographic record of waste placement will be obtained. This will beused during postgrouting destructive examinations.

4.1.3.1.3 Contamination Control—A number of contamination control measuressuccessfully tested during the Acid Pit Stabilization Project (Loomis, Zdinak, and Jessmore 1998) will beutilized for this field demonstration phase. Although the designs for contamination control are based onpast experiments in which a positive proof of concept was shown, any application of the proposedapparatus in a hot environment such as the INEEL SDA, would require refinement of these designs.INEEL Radiological Control support would be involved in these design efforts. Thrust block panels willbe placed over the test pit to provide a level working surface for the jet-grouting rig and control groutreturns. Once the pits are constructed, a foundation layer of pea gravel will be placed on the top of the pitto help eliminate sinking of the thrust block panels. The pits will be surveyed and the corner positionsand elevations established. Surveying measurements will be performed using INEEL procedures and willbe measured to a minimum of ± 3-in. increments. Markers will be placed on the pit to identify theposition and location of the thmst block installation.

Preconstructed thrust block panels will be delivered to the site and placed onto surveyed test sites.The thrust block will be approximately 12 to 17 in. thick, with a pattern that will allow for ample overlapto ensure the grouted columns merge into a solid form. Access holes will be constructed into the thrustblock for inserting the drill stem and catch cup assemblage. These access holes will be nominally 5 in. indiameter and spaced in a grid pattem approximately 18 to 24 in. apart on centers. Access holes will befitted with neoprene-type material to assist in cleaning the drill string as it is extracted. Figure 4-4 showsbasic design of the thrust block panel. In addition, a cap may be provided for each hole in the thmstblock. This cap would have a hole for air movement and would contain an air filter.

To control contaminant exposure to workers and the grouting equipment, the jet-grouting apparatuswill be equipped with a HEPA filter system and a collapsible shroud covering the drill stem. Thesemeasures assist in particulate control. The testing is to be performed only in a non-hazardous, non-radioactive environment. Contamination control hardware has been designed for proof of concept. Final

4-12

Fill material

Existmg grade

8-ft wastestream

Special nitratedrum placement

Figure 4-2. Design features of long-term disposal pit.

Box placed inbottom of pit

Overburden soilmachine compacted

2-ft soilunderburdencompacted

Thrust block

sideburdenrnachine compacted+

Special organicdrurn placement

GM99 0112

Quadrant 1 Quadrant 2

14"

/

Box 2

Box 1

Quadrant 3

14"

Quadrant 4

4 x 4 x 8-ft boxlocated on bottomof pit

Ng Nitrate drum(cardboard sided)located approximately4 ft from pit bottom

Organic drum(cardboard sided)located 4 ft frompit bottom

---------- 4 x 4 x 8-ft boxlocated on bottomof pit

3 x 4-ft region of random dump drums and sackswith no nitrates or organics N Location of hydraulic conductivity wells

GM99 0109

Figure 4-3. Plan view of long-term disposal pit (special waste orientation) with location of proposedwell locations.

4-14

Thrust block top view (isometric)

Thrust block rotated view bottom (isometric)

Figure 4-4. Basic thrust block module design.

4-15

design efforts associated with the contamination control system require deployment of industry standardhardware and will be included in the final design phase of the remedial action. Such a system will involvespecial fittings and adapters for the collapsible shroud that covers the drill stem. In addition, the need fora volatile organic absorber, carbon filter, in line with the HEPA filter will be assessed in this stage oftesting. These details are considered more appropriate for final remedial design activities. In summary,the contamination control design used for the treatability study is planned for short-term use only;however, the efficiency of the design for that short term should be adequate to show the control ofcontamination spread by evaluating dust and tracer spread during the various operations. A catch cansystem will be used at each grout hole to contain flow from the jet-grout nozzles during repositioning ofthe jet-grout system when transferring between holes or moving off the thrust block. A catch cup will beused to assist with containing excess grout during drill stem transfer between grout holes. Spillcontainment consisting of absorbent material and a collection pan will be placed over each access hole tocontrol minor drips and spills of clean grout during removal of contamination control devices. Figure 4-5provides a schematic of basic jet-grouting contamination control measures. Figures 4-6, 4-7, and 4-8 areillustrations of these contamination control measures.

After placement of the thrust blocks, a weather structure will be erected to permit accuratemonitoring of airborne contaminants during grout emplacement. Air samplers will be stationed along theperimeter of the test area and continuously run to test for airborne contaminants. Air sampling data willbe used to evaluate the effectiveness of the contamination control system.

Access driveways and turnarounds for supply and equipment trucks and jet-grouting rig checkoutswill be established depending on test setup orientation and access to already existing paths. Thesedriveways and turnarounds will be dirt and gravel pathways. Facility equipment and operators will beused to develop these access paths.

The jet-grouting/drilling rig and supply equipment (mixers, high-pressure pump, transfer pump,grout supply lines, exhaust lines, generator, grout supply tanks, water tanks, etc.) will be staged in an areaoutside the established simulated exclusion zone for easy access. For the field study, the weatherstructure will most likely be the exclusion zone. This will minimize the need for personnel andequipment to enter the exclusion zone area unnecessarily. The jet-grouting apparatus will initially bestaged outside the exclusion zone for equipment setup and checkouts and moved inside the exclusionzone during grouting.

An area to place used materials (drill bits, drill strings, nozzles, etc.) will be established. This areawill be a temporary holding place for materials until the grouting process has been completed. Excessclean grout will be discharged into a holding area at the Cold Test Pit for later disposal.

Work zones, to be specified in the Health and Safety Plan, will be stationed and properly marked.All restrictions for entering these zones will be posted, and prefab briefings will be held to inform siteworkers of procedures for working in these zones.

4.1.3.2 Grout Emplacement. The field test will provide essential information for theimplementability of this technology and include evaluation and review of the jet-grouting apparatus, fieldoperations, grout mixing and delivery logistics, contamination control equipment and measures, thrustblock stability and functionality, equipment troubleshooting measures, equipment laydown process, andtransfer operations from grout hole to grout hole. All test observations and field measurements will berecorded in logbooks by field personnel.

The grouting rig and support equipment/materials will be staged in designated areas. The jet-grouting apparatus checkout and parameter settings will be performed outside the simulated exclusion

4-16

To HEPAfitirationsyslem

Thrust block

Flexiblevent hose

HEPA boot

Rubber catch cup2-in. ID larger thanHEPA boot at top

i iper material

(a) Overall system (drillslem engaged in hole)

(b) Overall system(drill stem withdrawn)

Attachmentring

Catch can tor transitbetween holes

Figure 4-5. Schematic of basic jet-grouting contamination control measures.

(c) Overall system(moving to new hole

with catch can)

GMS9 0145

4-17

HEPA vacuumsystem

Figure 4-6. MIA Vacuum system installed on drill.M98 0010

Drill stem

Catch cup

HEPA hose

Figure 4-7. Features of contamination control s s stern.

Catch cmounang br.AcKel

M98 0009

Car,'It 111 ,1,

Figure 4-8. Catch can installed at the bottom of the catch cup and drip pan showing grout droppings.

zone. After equipment staging, system checks will be performed to ensure proper operation beforeinitiation of the grouting process. These checks will include (a) calibrating the flow meters to measurevolume of injected grout: (b) setting initial grouting parameters (i.e.. step distance. step rate. and drillstem rotation): (c) testing contamination control equipment: and (d) flushing the pumps and drill systemto remove residual materials. Once the equipment has been deemed fully operational and parametersproperly set, system operations will be throttled down to produce a trickle flow from the nozzles. A catchcan will bc attachcd to the end of the drill string to collect the grout material during relocation. Groutflow will continue between system moves to ensure that thc grout material does not harden insidc thcjci-grouting apparatus clogging the lines and nozzles. The jet-grouting apparatus and high-pressure lineswill be moved onto the thrust block structure. The grout material collected in the catch can will bedeposited under the thrust block. It is planned that the equipment checkout and parameter settings will beperformed after each full-system shutdown or cleanout cycle. The jet grouting will be performed undervendor subcontract using vendor equipment and personnel. Approved vendor procedures for jet groutingwill hc used in conjunction with [NEEL work processes as necessary.

Grout mixing will occur at an onsite batch plant. Batch samples will be collected directly from themixer (concrete truck or batch plant) before grouting is initiated and tested for viscosity and density.Viscosity will be measured according to the API Procedure RP-13B-1. "Recommended Practice StandardProcedure for Testing Drilling Fluids." Density will be measured following ASTM 1)4380-84(Reapproved 1993). "Standard Test Method for Density of Bentonitic Slurries."' Grout mixturesmeasuring outside the specified viscosity range will be rejected and a new load delivered that meetsviscosity specifications and requirements.

1-20

After material testing and grout acceptance, the jet-grouting rig will be positioned over a cleanoutarea to remove water from the system. Once checkouts have been performed, the jet-grouting apparatushas been properly positioned over the thrust block, and contamination control measures are properly inplace, the grouting process can be started. All grouting will be performed at nominally two revolutionsper step, at a step distance of 5 cm (1.97 in.) per step and at a step rate of 6 seconds per step. Injectionpressure is planned for 6,000 psi. These parameters may be varied, depending on grout material used,equipment checkout tests, and other optimization determinations learned from the implementability tests.

4.1.3.2.1 Grouting Operation—A numbering system will be assigned for thrust blockholes, and all operations will use the same numbering system. The grouting sequence will use a modified"r pattern (described in Loomis et al.) to allow for partial grout curing and to minimize communicationbetween the freshly grouted holes. The first hole grouted will confirm proper settings of groutingparameters. The basic injection process is as follows:

• Position jet-grouting rig with catch can over access hole on thrust block.

• Remove catch can and position catch cup assemblage into access hole on thrust block.

• Extend the drill stem through the thrust block to ground surface and drill to designated depth.It is expected that grouting will start nominally at the bottom of the waste seam and extendnominally 6 in. above the top of the waste seam. Actual grouting depths will be specifiedbased on dimensions of jet-sub/drill bit assembly.

• Commence high-pressure injection when total depth is reached and retract drill stem accordingto specified parameters to a prescribed depth and discontinue high-pressure pumping.

• Retract drill stem into catch can and allow system to drain.

• Raise catch can and drill stem simultaneously and connect catch cup to contain low-pressuregrout flow.

• Position rig in a designated area to permit contamination sampling (when required) or cleanuparound the hole.

• Remove spill containment materials and clean up any spillage or surface returns.

• Move to next hole and repeat the procedure again.

4.1.3.2.1.1 Placement of Hydraulic Conductivity Boreholes—A series ofboreholes will be created in the pit using a to-be-determined method. This method will most likely beapplied prior to curing of the monolith. Hydraulic conductivity tests will be performed using theseboreholes.

4.1.3.2.2 System Cleanout—The grouting process will continue until system shutdown orcleanout is required. This may be at the end of a workshift day, system failure, and/or facilityemergencies. Prior to shutting down, whether after completing the day's grouting activities or formaintenance purposes, the jet-grouting apparatus will be flushed and cleaned to remove unused grout andwater circulating through the system. The basic cleanout process will consist of the following procedures:

• Move the drill rig to the cleanout trough and position for removal of material under simulated

4-21

contaminated conditions

• Lower the mast and extend the drill stem to expose the breakout joint

• Install a rubber guard onto the exposed drill stem above the breakout joint

• Decontaminate the exposed drill stem and jet-sub/bit assemblage

• Move the rig over the second trough for cleaning under noncontaminated simulated conditions

• Break apart and remove the jet-sub/drill bit assemblage from drill stem

• Transfer removed bottom-hole assemblage to designated area for further cleaning

• Drain grout from drill stem

• Attach cleanout sub/hoses and connect hose to cleanout tank

• Begin flushing by running water into transfer pump and pump under low pressure(50 to 100 psi)

• Continue flushing until clear water is observed discharging into cleanout tank

• Disconnect hose and reconnect cleaned jet-sub/drill bit assemblage

• Dismantle low- and high-pressure pumps for intemal cleaning.

Figure 4-9 shows a schematic of this cleanout process.

Rubber donut

Catch can

High-pressureinjection pump

Thrust block

Figure 4-9. Schematic of cleanout process.

Drill sleeve

Nozzle/bit

Thrust block

Compatible coupling

Flexible firehase

inside, covered and vented calchbasin 300 gal/minimum

GM99 0146

4-22

Approved vendor procedures will be used to operate and maintain the jet-grouting apparatus;however, material collection and disposition may be modified as deemed necessary. All unused groutwill be discharged into a containment area constructed at the Cold Test Pit. All waste will be segregatedand labeled for proper waste disposition as discussed in the Waste Management/Waste MinimizationPlan.

4.1.3.2.3 Data Collection—During the grouting process, the following operational data willbe recorded to evaluate the implementability of the in situ grouting technology:

Time to Grout. The time required to grout each hole will be tracked and recorded. Timing startswhen the drill string is lowered down through a thrust block hole and stops when the catch can is placedover the bit for system relocation to the next hole. The overall time to create the monolith will also berecorded. Any down time due to equipment failures or other problems will be recorded separately andlater added to the total time to grout the hole for averaging calculations. Time will be measured to± 1 minute.

Quantity of Grout Material. During the grouting process, the total grout injected in each hole willbe measured to ± 5 gal, and the grout returns to the surface will be estimated for each hole at ± 5 gal perthrust block module. In addition, the amount of grout material necessary to fill the void space of eachthrust block module will be measured and recorded. Again, measurements will be to the —5 gal.

Total Depth Measurements. The total depth drilled below the thrust block surface will be trackedand recorded for each grout hole. The drill string will be strapped in order to make accuratemeasurements at any time during the grouting/drilling operation. Depth measurements will be made tothe ± 5 cm (± 2 in.). In addition, the depth at which the jet-grout injection is stopped during drill stringextraction will also be recorded. All measurements will be measured from the thmst block surface andcorrected for ground-surface elevations.

Parameter Settings in Grout Operation. During grouting, injection pressure, step distance(retrieval distance), step rate (time between steps), average drill string rotation rate, and total injectionvolume will be recorded for each hole. It is anticipated that these parameters will be fairly consistentduring the course of a day. However, these parameters may be varied while grouting or may be changedbetween grout holes. The injection pressures will be recorded to ± 100 psi, the step distance will berecorded to ± 0.5 in., the step rate will be recorded to ±1 second/step, the rotation rate at ± 0.5revolutions/step, and the total injection volume at ± 5 gal .

Volume Increase. The subsurface material volumetric increases (surface heave) will be assessedduring the curing process. This will be performed by resurveying the comer and center positions(coordinates and elevations) of the thrust block after grout curing and comparing results with the previoussurveying measurements taken when the thrust block construction was completed. INEEL surveyingprocedures and equipment will be used. Again, surveying measurements should be within ± 3 in.

Quantify Secondary-Waste Stream. Secondary waste will be produced during the grouting process.These wastes will be managed in accordance with the Waste Management/Waste Minimization Plan asnecessary. The volume of secondary waste generated during the grouting and sampling processes will bedocumented. An assessment of grouting hardware that contacts the tracer-contaminated soils will be usedto evaluate potential contamination of such hardware during grouting.

4.1.3.2.4 Contamination Monitoring—To evaluate the effectiveness of the groutingprocess to control the spread of contamination, the following data will be collected.

4-23

Contamination Control Performance Monitoring. Contamination control and rare-earth tracerspread will be evaluated during grouting activities using 100 cm2 smears, high-volume filters, and solidsamples of grout returns. All these samples will be evaluated by a inductively coupled plasma-massspectrometry (ICP-MS) laboratory for the tracer materials present in the field test pit. Test results will beused to evaluate the effectiveness of the contamination control measures to mitigate contaminationexposure to workers, equipment, and the environment during grouting. The sampling scheme summary isprovided below.

A total of approximately 70 holes will be grouted. Air sampling will be continuous; however,smear samples shall be obtained from the top surface of the thrust block near the current grout hole andon the drill string for the odd number holes starting with hole number 1. Background smears will becollected prior to starting the grouting process. One smear will be collected from the thrust block surfaceand one smear from the drill string.

In addition to the smear samples, a "spoor?' sample will be obtained from the grout returns in theodd number holes starting with hole 1. Each grout sample will be collected with a stainless steellong-handled spoon that has been appropriately decontaminated and wrapped in aluminum foil. Asampling spoon will not be used at more than one hole unless appropriately decontaminated between uses.The preferred method is to use a separate clean spoon for each hole. The spoon samples will be placed ina plastic jar, labeled and dated, and the smears placed in plastic bags, labeled, and dated.

During grouting, five high-volume (25 cfm) air samplers strategically placed around the groutingoperation will be continuously running. These samplers will be calibrated by the INEEL CalibrationLaboratory and guaranteed to ± 10% for totalized air flow. The filters will be collected from the samplerswhen the load on the samplers requires changeout according to manufacturer specifications. For a givensampling interval, the filters will be composited and handled as one sample. After weighing theindividual samples, the composite filters will be placed in a plastic bag and labeled and dated. The datawill include initial weight (± 0.1 mg), total air flow (± 10% of reading), and final weight (± 0.1 mg). Onebackground composite of the five filters will be collected prior to grouting. If the caps for the thrust blockholes are used, a filter material from these caps will be analyzed the same as the air samples. The ICP-MS laboratory will evaluate all samples within the stated measurement capability. The ICP-MSlaboratory has a rigorous quality assurance program involving tracer standards and replicates, and theprocedures are described in the Analytical Chemistry Environmental Chemistry Laboratory (ECL)Standard Operating Procedures (SOP) IM-6.1. The process involves digestion described by the ECLSOPs IP-1.3. A laboratory statement of work will be established through the Sample Management Office(SMO) to perform sample analyses.

Before shutting down the jet-grouting apparatus, either after completing a normal day's groutingoperation or for maintenance purposes, clean grout and wash water will be flushed through the grout-circulation system into a storage tank, as described above for cleanup procedures. To establish tracerconcentrations to determine effectiveness of the contamination control equipment, water/grout sampleswill be collected from the cleanout storage tank each time the system is flushed. It is assumed that thesesamples will be a mixture of the cleanout water and remaining grout material. Up to five water/groutsamples will be collected and analyzed for tracer compounds.

4.1.3.3 Postgrouting Evaluation. After grout emplacement, data will be collected to evaluate(a) curing temperature of the monolith, (b) measure hydraulic conductivity of the emplaced monoliththrough emplaced wells, and (c) the monolithic nature of the pit by dismantling if for a visual examinationof the monolith. Samples of the monolith will be collected during the destructive examination forphysical and chemical testing. Data collected during evaluation will be used to determine

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implementability and effectiveness of the technology. Testing requirements are discussed in thefollowing subsections.

4.1.3.3.1 Temperature Measurements—Temperature measurements will assist indetermining the overall curing time of the monolith and in determining thermal effects at depth duringcuring. This is important because curing in a large monolith could be higher than that observed in smallblender samples. It is planned to install two sensors at depth within the monolith to measure temperature,one at the monolith center and the other near the edge of the monolith. The probes will be positioned atthe mid-level depth of the monolith. A portable data logger will then be attached to the sensors and usedto measure and record in situ temperatures. The temperature measurements will be recorded once thegrouting process has been completed and will continue until the monolith temperature has reachedequilibrium, or after 3 weeks, whichever comes first. Temperature recording frequency will beapproximately every 20 minutes for the first week of observation. The frequency may be reduced asreasonable as the curing process progresses and equilibrium is approached. The time indexes will also belogged for the temperature measurements. The temperature measurements will be to ± 1°F. The timemeasurements will be ± 5 minutes. Temperature data will be compared with previous measurements todetermine effects with grouting under these conditions.

4.1.3.3.2 Hydraulic Conductivity Measurements—The need for hydraulic conductivitymeasurements of treated buried waste arises because movement of groundwater through buried waste isone of the most important mechanisms for mobilizing contaminant materials. The hydraulic conductivitydata are one of the variables used to estimate the risk posed by the waste to human health and theenvironment. In situ grout can dramatically reduce the movement of ground water. Laboratory hydraulicconductivity measurements are needed for grout selection and also as a baseline standard of comparisonfor materials used in the field. The data used for the estimation of risk is obtained from fieldmeasurements because laboratory measurements cannot be scaled to the field dimensions.

The ideal field hydraulic conductivity measurements would be carried out on hydraulicallyhomogeneous material and would be a measurement of "buried waste." It would involve a composite ofsoil, neat grout, boxes, drums, and grout-sludge mixtures. Measurements of any single component ofmonolith such as soil and grout mixtures are not representative of overall monolith hydraulicconductivity. Treated buried waste is made up of a mixture of large boxes, drums, soil, and various kindsof debris. The requirement of homogeneity means that the volume measured for hydraulic conductivity islarge compared with the dimensions of the articles in the waste such as boxes, drums, etc. If thehomogeneity requirement is not met, then hydraulic conductivity measurements in the buried waste arevery difficult to quantitatively interpret because the contribution of each component of the buried waste isunknown. The relation of such measurements to the "hydraulic conductivity of buried waste" is alsounknown because the integration function is unknown.

The standard methods used to measure hydraulic conductivity in the field are designed to measuresoil, concrete, or similar materials, all of which are homogeneous at the scale of the measurement. Noneare heterogeneous at the scale of dimensions of buried waste. The choice of method for the measurementof buried waste reduces to choosing a method that most nearly approximates the measurement of ahomogeneous material. This is so because no standard method exists that is directly applicable to "buriedwaste" without modification of the standard measurement method.

The accuracy of hydraulic conductivity tests is highly dependent on spatial variability of soilstested. Hydraulic conductivities (KA values) are log-normally distributed rather than normally distributed.This means that most of the net flux of water occurred in a few permeable locations. Thus, if waste buriedin soil behaves similarly to natural soil, the measurement of multiple sample locations may not reflect Kfsvalues of the site being tested (Klute 1986).

4-25

Standard borehole methods are summarized from ASTM-5126, "Standard Guide for Comparison ofField Methods for Determining Hydraulic Conductivity in the Vadose Zone," and other informationsources as indicated.

Infiltrometers are instruments used to measure the rate of water infiltration at ground surface. Ingeneral, infiltration measurements are affected by both hydraulic conductivity and capillary effects andare restricted to measurements at ground surface. The sealed double ring infiltrometer (ASTM D 5093) isone of the most sophisticated of the infiltrometer methods and was designed to measure the hydraulicconductivity of landfill clay liners. The apparatus consists of a 12-ft square outer ring surrounding asimilar 5-ft inner ring. In operation, the rate of water infiltration in the inner ring is measured and thewater is assumed to move only vertically downward. The lateral movement of water in the inner ring isminimized because water from the outer ring is also percolating downward, as well as laterally(Daniel 1989). The system works well for landfill liners because the thickness of the liner is less than thewidth of the inner ring and the clay liner is homogeneous. In this case, the assumption of vertical watermovement in the inner ring is reasonable. The field test pit described in this work plan does not exactlymeet the assumptions required for successful application of the sealed double ring infiltrometer. Thedimensions of the test pit are 14 x 14 ft and the thickness of the waste seam is 8 ft. The waste seam ismade up of simulated waste including debris, drums, and boxes. The treated buried waste is nothomogeneous, the size of the drums and boxes is similar to the inner ring, and the waste seam is muchthicker than the size of the inner ring. Direct application of the system as described in ASTM D 5093would initially give an estimate of the hydraulic conductivity of the upper surface of the monolith, whichis usually a soil-grout mixture. There is no apparent way to determine whether this measurement isrepresentative of the treated buried waste seam. If the time of measurement is extended so that thewetting front penetrates to greater depths, the assumption of vertical water movement becomes lesscertain and is violated when the wetting front reaches the drums and boxes. The problem is complicatedbecause the top of the monolith is not smooth. It is made up of a set of grout columns spaced at about 2-ftcenters extending to ground surface. Application of the double ring infiltrometer would require theirremoval without disturbing the hydraulic properties of the monolith. Taken together, the aboveobservations suggest that the sealed double ring infiltrometer and similar instruments are not suitable forapplication to the in situ grouting monolith hydraulic conductivity measurement.

Borehole tests are the only currently available tests to measure Kfs at different depths within thesoil profile (see ASTM D5126, Sec 4.1.6.2, p 478).

While similar to one another, the borehole permeameter methods differ in techniques used to createthe boreholes.

A cylindrical borehole is drilled, or created in some other way, into the zone to be tested. The rateof water infiltration necessary to maintain a constant head, along with predetermined lateral capillarydata, is measured and used to determine an infiltration rate. The method can obtain values in soil at E-6to E-8 cm/s if water evaporation effects are accounted for. The borehole method can be applied at anydepth (ASTM D5126).

A variation of this test consists of conducting multiple measurements in the same borehole but withdifferent ponding depths. The measurements are used to independently solve the simultaneous equationsfor hydraulic conductivity and capillarity flow (ASTM D5126).

Another variation (U.S. Department of Interior 1977) of this technique utilizes a pneumatic packersystem to seal the borehole. This technique is accurate in media having hydraulic conductivity values toE-7 cm/s. A section of the borehole is sealed using the packers; the borehole region to be tested is filledwith water under pressure. The water flow rate is measured as a function of pressure.

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A11 borehole techniques assume that the borehole drilling operation has no significant effect on thetest medium. Traditional drilling methods often cause disruption of the grouted waste. Drilling usingwater cooling will involve hundreds of gallons of cooling water per hole, which also erodes the medium(Loomis et al. FY-96 hmovative Subsurface Stabilization Project). An unconventional method is to use atube-in-tube approach in which an outer tube is perforated and a friction fit inner tube is placed within theouter tube. This assembly is then placed into the monolith prior to curing within the holes created by thegrouting operation. Once cured, the inner tube is withdrawn, thus creating a borehole for measurements(the water fills the outer tube and enters the matrix via the perforations in the outer tube). A differentapproach (Lowry et al. 1999), still in the development stage, uses a cone penetrometer, which is pushedinto the treated waste to the depth where the hydraulic conductivity measurement is to be made.

4.1.3.3.3 Destructive Examination—After completion of the hydraulic conductivitytesting, the monolith will be exposed for examination and sampling and eventually dismantled in asystematic manner. Monolith examination will be used to evaluate the implementability of the groutingprocess. Monolith samples will provide data for determining the effectiveness of the grouting technologyto provide long-term stabilization and act as a bather for water infiltration. Some of these measurement-of-monolith properties are direct input variables for the risk assessment model and will be used forcalculation of the specific risk reduction as a function of time associated with this treatment application.

Following removal of the weather structure, the monolith will be excavated and examined asfollows. The top overburden material will first be removed from the original boundaries of the pit. Next,the monolith will be isolated leaving a freestanding entity for further evaluation and sample gathering.Detailed observation will be made of the structural integrity of the monolith. The monolith will bemarked into quadrants and subareas for representative sampling based on the photographs taken during pitconstruction. The approximate dimensions of the monolith will also be measured with a handheld tapemeasure. Once roughly isolated, the monolith will be further exposed by removing incremental sectionsin approximately 6-in. sections while trying to maintain a nearly vertical face. The face will be describedin a logbook and a photographic record will be kept. In the photograph will be a marker sheet of paperdescribing the location relative to the original face of the monolith. The destructive examination willremove the monolith while keeping records. The excavation will be performed by INEEL personnel withstandard heavy equipment (backhoe, front-end loader, fork lift, etc.).

During the examination, the monolith will be examined for (a) grout permeation (ratio of grout tosoil to waste and void presence), (b) degree of bonding between grout and waste, (c) monolith crackingand spalling, (d) areas of set retardation and impeded curing, (e) zones of incomplete mixing orcomponent separation, (f) areas of monolith swelling and disintegration, and (g) penetration of fluorescentdye in the hydraulic conductivity holes. The purpose of this examination is to evaluate the monolithdevelopment to assess implementability and relative effectiveness of the grouting process.

As part of this survey, a fracture assessment will be performed of the monolith, particularly notingthermal-mechanical stresses such as (a) degree of fracture penetration into the monolith, (b) fracturezoning and orientations, and (c) fracture spacing and aperture dimensions. Assessment of the fracturenetworks will be used to qualitatively predict their effects on the monolith's permeability.

During the destructive examination, samples will be collected for physical and chemicalcharacterization. The monolith will be sectioned into quadrants for interval representative sampling.Each sample will be logged and described in the logbook. Samples will be placed on plastic sheeting onthe ground surface and thoroughly examined. Recovered samples will be marked, labeled, andphotographed. A11 samples will be properly stored at a designated area at the Cold Test Pit. To ensurelaboratory services meet data quality requirements, contracting documentation will be coordinated

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through the INEEL SMO. Management of waste material will be specified in the WasteMinimization/Management Plan. Testing requirements are listed in Table 4-6.

Test methods for porosity, tensile strength, compressive strength, density, pH/redox potentialaccelerated leach test were previously discussed in bench testing. Test methods for hydraulicconductivity, unsaturated flow, and analytical tests for nitrates are presented in Table 4-6. Test resultsfrom monolithic sampling will be compared with bench test results to evaluate property changes producedby grout emplacement in the soil/waste form matrix.

Hydraulic Conductivity. Hydraulic conductivity is a measure of the resistance of a material to thepassage of water. Hydraulic conductivity will be measured following ASTM D-5084-90, "A StandardTest Method for Measurement of Hydraulic Conductivity of Saturated Porous Materials Using a FlexibleWall Penneameter." Test results will be compared with results from the postgrout full monolith hydraulicconductivity testing to evaluate monolithic versus localized measurements.

Unsaturated Flow. Movement of water in the unsaturated zone is of considerable interest fordetermining quantity of water flux and water content of soil. Unsaturated flow determinations will bemeasured following ASTM D-3152-72 (Reapproved 1977), "Standard Test Method for Capillary-Moisture Relationships for Fine-Textured Soils by Pressure-Membrane Apparatus." This test methodcovers the determination of capillary-moisture properties of fine-textured soils as indicated by themoisture content-moisture tension relationship determined by pressure-membrane apparatus usingtensions between 1 and 15 atmospheres. Moisture tension (matrix suction) is defined as the equivalentnegative gage pressure, or suction, in soil moisture. Moisture content is a measure of the water retainedin the soil.

Analytical Testing. Select monolith samples will be analyzed for nitrates to evaluate thestabilization properties of the waste/soil/grout matrix. Nitrate concentrations will be measured accordingto EPA Method 300.

Table 4-6. Testing methods for monolith samples.

Test

Porosity

Tensile strength

Compressive strength

Density


Oxidation/reduction potential

Hydrogen ion activity (pH)


Moisture-capillary relationship

Nitrates

Test Method

ASTM C-642-90

ASTM C-496-90

ASTM C-39-96

Instrument specifications

ASTM D-5084-90

EPA Method SW-9045

EPA Method SW-9045

ASTM C-1308-95

ASTM D-3152-72

EPA Method 300

Data Usage

Hydraulic properties


Implementability

Implementability


Chemical buffering

Chemical buffering

Grout dissolution

Unsaturated flow

Contaminant stabilization

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4.2 In Situ Grouting for Confinement During Retrieval

A paraffin-based grout called WaxFix will be used as the chosen grout for in situ groutingconfinement during retrieval. Specific testing objectives for confinement during retrieval that will beaddressed by this testing strategy are:

• Determine the effects of the paraffin-based grout on the emission of dust that may containalpha-emitting radionuclides during excavation

• Determine implementability of boron additive to the paraffin-based grout to absorb neutronsand eliminate criticality concerns regarding paraffin as a neutron modifier or reflector

• Determine the effect of paraffin-based grout on the Btu content of the wastc.

Confinement during retrieval will provide interim encapsulation of contaminants during soil andwaste retrieval and handling operations. This technique will become important if retrieval is selected as apart of the remedial action.

From previous INEEL research and demonstration programs, WaxFix grout has shown excellentpermeation properties and has displayed the capability to penetrate into the pores of solid surfaces and toencapsulate sludge materials. Based on these past results, WaxFix grout has been selected forconfinement during retrieval application.

Grouting and operational procedures described for long-term disposal will be used for confinementduring retrieval. Testing will be divided into the following three testing phases:

• Bench testing

• Implementability testing

• Field testing.

4.2.1 Bench Testing

Technical support for bench testing will be provided by an offsite laboratory and will consist of thefollowing three tasks:

l. Determine maximum boron concentration that can be successfully added to theparaffin-based grout without altering grout properties

2. Measurement of temperature to develop a cooling profile

3. Evaluation of the Btu value of the retrieved grout waste form

4. Department of Transportation (DOT) oxidizer test.

These tasks will be described in the following subsections.

4.2.1.1 Effects of Boron Additive on the Properties of the Paraffin-Based Grout.Fissionable materials in the waste will be present as oxides. These wastes are not currently configured toallow criticality, but the neutron reactivity of thc system may be affected by the addition of paraffin either

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through reflection or moderation. Paraffin is a typical reflector and may also be an effective moderatordue to its high hydrogen content. A reflection is a material that reduces the escape of neutrons byreturning them to the source. A moderator slows neutrons and reduces their escape. Therefore, theaddition of paraffin to waste containing fissionable contaminants may increase neutmn moderation andincrease the potential for criticality. Although injection of grout should mix the waste and distributefissionable material throughout the monolith, there are processes that could potentially create localpockets of concentrated fissionable material capable of producing criticality.

Boron effectively absorbs neutrons even at low concentrations. Bench samples will be preparedwith a boron/borate grout additive to address the possibility that concentrated fissile material could be aconcern. A solution of boron/borate and glycerin (solubility = 250 g/L) will be added to the moltenparaffin in three concentration (0.1 mL/L paraffin; 1 mL/L of paraffin; and 5 mL/L of paraffin). Thcresulting samples will be allowed to cool and then tested to determine their physical characteristicsincluding set time and durability. These results will be used to determine the maximum concentration ofboron that can be added in this manner. The boron solution will be dyed dark red, and the distribution ofboron in the grout samples will be determined by visual observation of color or by photometricmeasurement of light absorbance.

A white paper will be developed to evaluate the potential for criticality induced by the use ofparaffin-based in situ grouting at the SDA and also the ability of a boron additive to attenuate any adverseeffects of the paraffin as grout.

4.2.1.2 Temperature Measurements. A cooling profile for the paraffin-based grout will beprepared during bench testing. The cooling profiles will be used in comparison with previousinvestigation results to determine the effects of boron addition on grout behavior and monolithdevelopment.

For measuring cure temperature, temperature sensors will be inserted into a subset sample of eachgrout/boron mixture after initial preparation. A portable data logger will be attached to the probe andused to measure and record in situ temperatures. Temperature recording frequency and instrumentaccuracy will follow procedures described in the bench testing for long-term disposal.

4.2.1.3 Btu Content The effects of paraffin-based grout on Btu content will be determined frompublished data. Samples from the bench tests will be analyzed for Btu content. This parameter will beused in evaluations of potential ex situ options, such as incineration, for the treatment of recovered waste.Btu will be determined using standard techniques (Heat of Combustion, ASTM D 240/D 3286).

Data obtained from bench testing of long-term disposal samples will also be evaluated to determineeffects of nitrates and organics on the physical and chemical properties of the paraffin-based grout. Thesedata results will be used to predict behavior of the paraffin-based grout during emplacement and formonolith development.

4.2.1.4 DOT Oxidizer Test. The DOT oxidizer test will be performed on prepared samples ofparaffin and nitrate salts with nitrate salt loadings of 12, 25, 50, and 75 wt%. Testing will be performedaccording to 49 CFR 173.127. This data will be used to assess the transportation requirements of anyretrieved waste using this grout/retrieval technology. This test is for information only and will not be apass/fail requirement.

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4.2.2 lmplementability Testing

The purpose of the implementability testing for the confinement during retrieval is to determine ifthe emplacement process is adversely affected by grout properties. A limited series of implementabilitytests will be performed to evaluate the jet-grouting application of paraffin-based grout with the boronadditive. This testing will provide essential information conceming the implementability, operationalaspects, and column development properties of the paraffin/boron grout.

Implementability testing will be conducted in soil conditions similar to the SDA. With a few minormodifications, the basic procedures described for implementability testing under long-term disposal willbe followed. It is expected that this testing phase will be conducted at the same time as the long-termdisposal. The grouting rig and support equipment will be identical to that described for the long-termdisposal application (Section 4.1.3.3), except the time on a step will be 5 seconds and the nozzle diameterwill be reduced to 2.3 mm. The grouting apparatus is identical to that used in the in situ grouting forlong-term disposal grouts, except that the high-pressure hoses and pump are heat traced and insulatedagainst heat loss. Cleanout of the molten paraffin will be accomplished by placing a manifold on thebottom of the drill stem and forcing hot water (greater than or equal to 160°F) through the pumpingsystem. The cleaning water/paraffin mixtures will be collected in a laydown area simulating a mobilecollection tank.

Initial preparation tasks will include construction of a test area similar to disturbed soil conditionsexpected at the SDA. Test area boundaries will be properly identified and field trial stations marked. Pitswill be constructed next to each field trial station for the collection and measuring of grout returns.

Paraffin-based grout will be emplaced in a minimum of three boreholes to ensure consistency withcolumn development. During the grouting process, field observations will be made to determine if theparaffin/boron mixture is pumpable and ensure that no operational problems during the emplacementprocess occur. Observations will focus on (a) mixing problems such as boron compound separation,(b) equipment fouling and residual build-up inside pumping equipment, and (c) other unusual operationoccurrences. The volume of grout returns produced during the emplacement will be quantitativelymeasured by routing the returns into a collection pit and manually removing the material with a 5-galbucket for measurement.

After emplacement, a temperature sensor will be inserted into each field trial station. A portabledata logger will be attached to the sensors and used to measure and record in situ temperatures.Temperature recording frequency will be approximately every 20 minutes for the first week ofobservation. The frequency may be reduced as the cooling progresses and equilibrium is approached.The time indexes will also be logged for the temperature measurements. The temperature measurementswill be actuated to ± 1°F. The time measurements will be every 5 minutes. These measurements will becompared with bench testing cooling results to evaluate effects of field emplacement.

The paraffin/boron field trial stations will be allowed to cool for approximately 1 week and then beexposed for examination. In past studies (Loomis et al. 1996), the paraffin field trials had solidifiedovernight; therefore, the proposed 1-week timeframe will be adequate. It is noted that in past testing themonolith will take considerably longer to solidify than the field-test holes because of the larger thermalcapacity of the pit versus that of single columns. Field trial stations will be exposed using a backhoe. Forthis procedure, the first step involves excavating to the top of the column and then examining the columnfor proper setting and column development. Once isolated, the field trial stations will be further exposedby removing incremental sections. Each exposed excavation face will be evaluated, and detailed fieldnotes and photographs will be taken. Detailed measurements will be recorded of the nominal dimensions

4-31

of the grout columns. Internal portions of the field trial stations will be inspected for completeness ofmixing, grout permeation, and boron distribution and separation.

Information from this study will be used to determine if any modifications are necessary foremplacing the paraffin/boron grout mixture in the field test such as modification of the thrust blockdesign. Any necessary operational and formulation modification will be made and tested beforeproceeding to the field testing phase.

4.2.3 Field Testing

The primary purpose of field testing is to evaluate the implementability and effectiveness of thetechnology in a field test arrangement that simulates the types of conditions expected to be found in theSDA. The field test will first involve grouting a specially designed test pit containing simulated waste.After curing, the grouted waste forms will be retrieved while evaluating contamination containment andcontrol. This phase of testing will divided into three tasks:

• Test area preparation

• Grout emplacement

• Postgrouting retrieval and evaluation.

These tasks are discussed in more detail in the following subsections.

4.2.3.1 Test Area Preparation.

4.2.3.1.1 Test Pit Construction—A test pit will be used for field testing of the confinementduring retrieval grouting technology. The test design is intended to complement the bench testingprogram discussed previously. Initial preparation of the field test pit will include excavation of a pit inthe Cold Test Pit area. This retrieval pit will be constructed in a similar manner to that used in typicalTRU pits at the INEEL. The basic dimensions of the pit of 14 x 14 x 8 ft deep will allow a full-scalegrouting/retrieval demonstration. The major features of the pit are shown in Figure 4-10.

The simulated waste for the confinement during retrieval demonstration will share the designfeatures and percentages with the simulated waste forms used in the field testing for long-term disposal.The waste container percentages of the total pit and waste form fractions are identical to those shown inTables 4-3 and 4-4 in Section 4.1.3.1.2. These percentages will result in a pit with two 4 x 4 x 8 ft boxes,forty-nine 55-gal drums, and fourteen 2 x 2 x 3-ft sacks as shown in Table 4-7. All drums will be linedwith 4 mil polyethylene sacks.

The pit will be constructed as follows. Two boxes will be placed in the bottom of the pit (one boxin each half of the pit). The remaining waste containers will be placed in a random manner.Approximately 1/4 of each waste type will be placed in one of the four quadrants. Figure 4-3 is aschematic for the disposal pit and this is identical to the retrieval pit except for placement of the wells. A4-ft high berm will be created around the outside of the pit after the two boxes have been placed. A layerof waste will be randomly placed to a level near the top of the berm without having waste materialsextending beyond the surveyed boundaries of the pit. At this point, soil will be used to fill voids in thepit. The area surrounding the berm will be built up with compacted soil. Further compaction of thebottom layer of waste and soil will occur. Using solid metal rods in the corner position as a guide, a new4-ft high berm will be placed around the top layer and the remaining drums will be placed.

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Thrust block

111111111111IIIIIMME111.1111111MINIIrreMIN eir tate

/ /Fig material"afe/". Aass Mal al if/rat tea

Existing grade

8-ft wastestream

Special nitratedrum placement

1Box placed inbottom of pit

Overburden soilmachine compacted

2-ft soilunderburdencompacted

Footer foundation

.Sbil.sitiehUrdenmachine compacted

Special organicdrum placement

Figure 4-10. Design features of in situ grouting confinement during retrieval pit.

Table 4-7. Simulated waste packages for the retrieval pit.

Waste Container Type Number Composition'

GM99 0111

Cardboard boxes 2 Metal debris (1/8 in. plate steel, tubing, piping, scrap metal), concrete/asphalt(4 x 4 x 8 ft) chunks (6-in. size) pulverized wood.

Metal 38%, concrete/asphalt 37%, pulverized wood 25%

Drums (55 gal)

Cardboard 25 Combustibles (cloth, paper, wood)

Cardboard 13 Inorganics (30 gal water; 139 lbm soil; 40 lbm dry Portland; 36 lbm NaNO3)

Cardboard 3 Organic (30 gal of Texaco Regal Oil; 100 lbm mirco cell-E;Metal 3 35 lbm kitty liter)

Cardboard 3 Nitrates (granular: 60 wt% Nallo3; 30 wt% KNO3; 5 wt% Na2SO4;Metal 2 5 wt% NaCI

Sacks (2 x 2 x 3 ft) 14 Cloth, paper(polyethylene)

a. Containers will be nunibered and labeled (combustibles, inorganics, organics, nitrates). Waste packages will contain varying amounts of theterbium oxide (Tb401) tracer in the following quantities: boxes-400 g; combustible drums-100 g; inorganic drums-200 g; organicdrums-50 g; nitrate drums--none; all sacks-100 g. The tracer is a fine powder with a particle size in the 3 micron size distribution.

Following completion of the pit there will be a 3-ft build-up of overburden using machinecompacted lakebed soil. On top of the overburden, a concrete footer approximately 2 ft high will providestabilization of the thrust block during grouting. With the footer, the combined space under the thrustblock is expected to be 3 ft, which should be sufficient to collect grout returns up to 40% of that using theWaxFix grout. Final design of the footers and thrust block will be performed following the8implementability tests.

4.2.3.1.2 Contamination Control—With the exception of the thrust block design, thecontamination control measures planned for long-term disposal will be used for confinement during

4-33

retrieval. During FY-96 demonstration testing (Loomis et al. 1996), copious grout returns were producedduring the emplacement of paraffin-based grout. To control this expected high volume of returns, thevoid space under the thrust block will be increased and structural support added to handle the expectedweight load of the grouting equipment. Final design will be determined after evaluation of the volume ofgrout returns produced during the intermediate testing. These preconstructed thrust block panels will bedelivered to the site and placed onto surveyed test sites. After placement of the thrust blocks, a weatherstructure will be erected to permit accurate monitoring of airbome contaminants during groutemplacement and retrieval. Air samplers will be stationed along the perimeter of the test area andcontinuously run to test for airborne contaminants. Air sampling data will be used to evaluate theeffectiveness of the contamination control system.

Access driveways and turnarounds, and staging and laydown areas will be the same as planned forlong-term disposal. Excess clean grout will be discharged into a holding area at the Cold Test Pit for laterdisposal. Work zones, as specified in the Health and Safety Plan, will be stationed and properly marked.All restrictions for entering these zones will be posted, and prejob briefings will be held to inform siteworkers of procedures for working in these zones.

4.2.3.2 Task 2: Grout Emplacement. The field test will provide essential information for theimplementability of this technology and include evaluation and review of the jet-grouting apparatus, fieldoperations, grout mixing and delivery logistics, contamination control equipment and measures, thrustblock stability and functionality, equipment troubleshooting measures, equipment laydown process, andtransfer operations from grout hole to grout hole. A11 test observations and field measurements will berecorded in logbooks by field personnel.

4.2.3.2.1 Grouting Operation—Grout rig and support equipment and grouting setup will bethe same as deployed for long-term disposal, except that the high-pressure hoses and pump are heat tracedand insulated against heat loss. It is anticipated that the same weather shield as used for the disposal pitwill be used over the confinement retrieval pit. The area surrounding the thrust block will provide agradual slope to the top surface of the thrust block. The grouting rig will penetrate the waste and providegrout in a triangular pitch matrix in a modified "r pattern. Grout injection pressure will be 6,000 psi.However, the time on a step will be 5 seconds and the nozzle diameter will be reduced to 2.3 mm. It maytake up to three days to emplace the paraffin-based grout depending on delivery schedule. The process issimplified by directly delivering the molten paraffin from the heated delivery truck to the supply pump.Clean out of the molten paraffin will be accomplished by placing a manifold on the bottom of the drillstem and forcing hot water (greater than or equal to 160°F) through the pumping system. The cleaningwater/paraffin mixtures will be collected in a laydown area simulating a mobile collection tank.Approved vendor procedures will be used to operate and maintain the jet-grouting apparatus; however,material collection and disposition may be modified as deemed necessary. All unused grout will bedischarged into a containment area constructed at the Cold Test Pit. All waste will be segregated andlabeled for proper waste disposition as discussed in the Waste Minimization/Management Plan.

4.2.3.2.2 Data Collection—During the grouting process, as with the long-term disposal, thefollowing operation data will be recorded to evaluate the implementability of the confinement duringretrieval grout and in situ grouting technology:

• Time to grout

• Quantity of grout material

• Quantity of grout returns

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• Total depth measurements

• Parameter settings in grout operation

• Volume increase

• Quantify secondary-waste stream.

4.2.3.2.3 Contamination Monitoring—Monitoring for contamination control performanceand contamination migration will be the same as planned for the long-term disposal. Data will be used toevaluate the effectiveness of the grouting process to control the spread of contamination.

4.2.3.3 Postgrouting Excavation/Retrieval Evaluation. After grout emplacement, data willbe collected to evaluate the curing temperature of the monolith and excavation/retrieval aspects of thegrouted waste forms. Data collected during evaluation will be used to determine the implementability andeffectiveness of the technology. Testing requirements are discussed in the following subsections.

4.2.3.3.1 Temperature Measurements—Temperature measurements will assist indetermining the overall cooling time of the monolith and also determine the thermal effects at depthduring the curing process. It is planned to install two temperature sensors at depth within the monolith tomeasure temperature, one at the monolith center and the other near the edge of the monolith. The probeswill be positioned at the mid-level depth of the monolith. A portable data logger will then be attached tothe sensors and used to measure and record in situ temperatures. Temperature measurements will berecorded once the grouting process has been completed and will continue until the monolith temperaturehas reached equilibrium, or after 3 weeks, whichever comes first. Temperature recording frequency willbe approximate]y every 20 minutes for the first week of observation. The frequency may be reduced asreasonable as the curing process progresses and equilibrium is approached. The time indexes will also belogged for the temperature measurements. Temperature measurements will be to ± 1°F. The timemeasurements will be ± 5 minutes. Temperature data will be compared with previous measurements todetermine effects with grouting under these conditions. These data will be used to construct a coolingprofile for the paraffin-based grout that will be used for comparison to previous investigations as oneindicator of effects of boron and buried waste constituents on the cooling behavior.

4.2.3.3.2 Excavation/Retrieval of the Paraffin-Based Monolith—Followingsolidification of the grouted matrix, soil surrounding the thrust block will be removed. First, the thrustblock will be removed from the top of the pit. This activity and all other operations within the weathershield will be conducted using five strategically placed air monitors to collect airbome tracers orplutonium surrogates. The thrust block will be completely removed from the weather structure.Secondly, the spoils collection pit debris (neat paraffin plus grout returns) will be removed from the pitand from the weather structure as a nearly solid block or blocks and the size of this block will berecorded. The overburden material will then be removed as a separate operation. The overburden will beplaced in 4 x 4 x 8-ft plywood boxes and removed from the weather shield. The overburden will beremoved to within 6 in. of the top of the waste matrix.

Two excavation campaigns will be conducted. The first campaign will be a demonstration oftop-down retrieval from the backside of the pit. The excavation will use a backhoe with Balderson thumband will remove an area approximately 7 ft in diameter to a depth of 8 ft to simulate a top-down hot-spotremoval operation. The second excavation campaign will involve creating a ramp leading to a verticaldigface. This ramp may start outside the weather enclosure and extend into the enclosure. A backhoewill peel off approximately 6 in. at a time and fill a 4 x 4 x 8-ft box with debris. A lay-down sheet will be

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placed under each box and a forklift will remove the boxes from the area when full. Air filters will bechanged periodically as required by the retrieval operation. The entire pit will be excavated includingdebris left over from the top-down retrieval operation. Following completion of the retrieval operation,the weather structure will be dismantled and all retrieved material will be staged for shipment to ahazardous waste disposal site as necessary.

Concentrations of tracer and dust in the air around the pit will be monitored duringexcavation/retrieval of the stabilized waste. During excavation, rare-earth tracers and airborne dust willbe monitored at the dig face and in the breathing zone of the workers. Tracers will be monitored in100 cm2 smears and in filter material recovered from high-volume filters. Analysis of collected sampleswill be by ICP-MS. Sampling will be conducted as described in Section 4.1.3.3.3.

4.2.3.3.2.1 Dust Suppression and Monitoring—The paraffin-based grout isintended to demonstrate dust control during excavation. In situ grouting for confinement during retrievalis being investigated as a means to reduce the emission of dust that may contain alpha-emittingradionuclides during excavation, thereby reducing worker exposure and costs associated with double-confinement structure or other containment alternatives. ff treatability study results indicate grouts can beused as a primary dust control mechanism, the technology will be considered as a portion of the SDAretrieval altemative in the feasibility study. A single-confinement structure or no structure at all may beadequate for recovery if the grouted waste proves sufficiently effective. The results will be quantified byevaluating the amount of collected tracer (terbium oxide) on filters and smears and the amount of dustcollected during the retrieval phase on high-volume samples. It has been shown that plutonium finesmove similarly to rare earth particles and lofted soil particles (Loomis et al., "Lanthanide Oxides asSurrogates for Plutonium Oxide During Simulated Buried Transuranic Waste Retrieval," WM-94,Tucson, Feb. 27-March 3, 1994). If the evaluation of filters and smears show virtually no spread of dustand tracer during the retrieval operation, then the idea of single containment or virtually only a weathershield could be a design criterion. The final decision to use containment would be part of the final designthat would utilize the data obtained as this treatability study.

4.2.3.3.2.2 Calculation of Required Dust Control—It has been estimated that a90-99% control of dust is required during retrieval operations to allow bubble-suited personnel entry tothe retrieval arena. This is based on past studies that show that plutonium fines move like dust fines(Loomis et al., "Lanthanide Oxides as Surrogates for Plutonium Oxide During Simulated BuriedTransuranic Waste Retrieval," WM-94, Tucson, Feb. 27-March 3, 1994). Therefore, controlling the dustis indicative of controlling the spread of plutonium. It is assumed that any retrieval operation will requirebubble-suited entry by personnel to allow maintenance or to actually perform the retrieval. To allow thisbubble-suited entry requires at least a 90% control of dust.

The estimated dust reduction fraction is determined by the following equation:

Expected Air Concentration—Concentration for Allowable Bubble-Suited Entry

Estimated Air Concentration

where the Expected Air Concentration is determined from estimated source terms and dust aerosolizationamounts during digging operations and the Concentration for Allowable Bubble-Suited Entry isdetermined from the INEEL Radiological Control Procedure MCP-356. The percentage of dust reductionis the difference between the estimated air concentration and the concentration for allowable bubble-suited entry divided by the estimated air concentration multiplied by 100.

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Allowable Bubble-Suited Operation—The derived-air concentration for unknown alpha-emittingradionuclides is 2 x 9 nCi/cc. This is an allowable breathing air limit for the unprotected worker.Workers in bubble suits have a protection factor at the INEEL of 1,000. Therefore, bubble-suitedpersonnel can enter areas with air concentrations of 2 x 10-6 nCilcc.

Mass of Waste/Source Term—The source term for buried TRU waste is difficult to estimatebecause of the heterogeneous nature of the waste. An SDA wide source term may be estimated frompoint source terms. Three cases are described below for estimating SDA source terms given defensiblepoint source assumptions.

Case I: Smith and Kudera, 1996, estimate there is 5,359 Ci of alpha-emitting rad onuclidescontained in 1.1E + 5 ft3 of waste. Assuming 100 lb/ft3 for the waste/soil matrix, a TRU source term forthe SDA is then 1.07 E-6 Ci/g or 1.07 E+3 nCi/g. Most of the TRU contaminants are not easilyaerosolizable or are surface contamination connected to debris. In glove box experiments at the INEEL,measurements of the percent of the source term that is lofted have been made (L. C. Meyer, TransuranicContamination Control Using Electrostatic Curtains [Proof of Principal Experiments] EGG-WTD-9336Nov. 1990). According to this reference, approximately 20% of this source term is available for spreadresulting in a corrected source term of 215 nCi/g. This corrected source term can be related to anaerosolized amount of material by assuming that the TRU contaminants move like soil during a retrievaloperation. In past operations, (INEEL, INT-98-00734) dust has been aerosolized at 1.0 E-7 g/cc;therefore, the TRU contaminants source term (215 nCi/g) would equate to an aerosolized TRUcontaminant rate of 2.15 x 10-5 nCi/cc.

Case 2: Another worst case source term can be determined by using the allowable amount ofplutonium in a container (200 g). Assuming that the container is a drum weighing 150 lb, this equates toa point source term of 1.88 x 105 nCi/g or when mixed with soil and lofted at 1.0E-7g/cc would result in1.88 x 10-2 nCi/cc. DOE Handbook for plutonium aerosolution (DOE-HDBK-3010-94) cites instances ofdrop tests on HEPA filters with 5% of the source term aerosolized. Ensuring that this worst case drumcontained 200 g of plutonium fines and using the 5% aerosolition factor results in 9.4E-4 nCi/cc loftedinto the air.

Case 3: A third estimate of the source term can be made by assuming a drum weighing 150 lbcontained the HEPA filters cited in the drop test in DOE-HDBK-3010-94. The HEPA filter in questionhad 43 g of plutonium. With 43 g of plutonium in a 150-lb drum, the source term would be 4.04 E4nCi/g. When combined with soil during a retrieva] effort and lofted at 1E- 7nCi/cc, the total maximumlofted source term would be 4.04 E-3 nCi/cc. Assuming that only 5% of the possible source term is loftedresults in an estimated source term of 2.02E-4 nCi/cc.

Estimated Dust Reduction—Using the equation for estimated dust reduction the requiredreduction for bubble-suited entry for Case 1: (20% aerosolition of an SDA average source term) is:

2.15 x 10-5 nCi/cc — 2 x 10-6 nCi/cc2.15 x 105 nCi/cc

x 100% = 90%

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For Case 2, the dust reduction (maximum plutonium loading) required for bubble-suited entrywould be:

9.4E-4 nCi/cc — 2E-6 nCi/cc 9.4E-4 nCi/cc x 100% = 99.7%

For Case 3 (HEPA filter with 5% aerosolution), the dust reduction required for bubble-suited entrywould be:

2.02E-4 nCi/cc — 2E-6 nCi/cc2.02E-4 nCikc x 100% = 99%

If the average source term is used in conjunction with a 20% aerosolution rate as in Case 1, only a90% control would be required. However, with more restrictive local source terms there could be caseswhere 99%+ would be required. Therefore, when evaluating the technology for implementability, theproject will be looking for a minimum dust control of 90% and a maximum of 99% for meetingimplementability criteria. In actual practice, the less restrictive 90% requirement could be applied; and, ifthere were local "hot spots" of plutonium encountered, special decontamination techniques would beapplied to interior surfaces of the retrieval area prior to bubble-suited entry.

It is noted that in addition to grouting, confinement would still be required (DOE Orders 6430.1Aand 420.1). The confinement could be a simple structure with negative pressure ventilation. In additionto preventing a release, the confinement would provide protection from the elements. This confinementstructure would be used only after evaluation of the results from the treatability study. If needed, anyventilation system for the confinement structure would require some combination of HEPA filters,prefilters and possibly carbon filters. There will be no simulation of the ventilation system in thetreatability study; rather, a simple weather structure will be used.

4.2.3.3.2.3 Btu Content—The effects of paraffin-based grout on Btu content will bemeasured by sampling the waste form excavated during monolith retrieval. Several systematic samples ofthe monolith will be collected and analyzed for Btu content. The parameter will be used in evaluatingpotential ex situ options, such as incineration, for the treatment of recovered waste. Btu will bedetermined using standard techniques (Heat of Combustion, ASTM D 240/D 3286). Test results will becompared with bench tests to evaluate effects of the grout emplacement process and mixing with buriedwaste.

4.2.4 Cost Information

During the course of the in situ grouting treatability study, costs associated with raw materials,operations, equipment, hardware, waste management, verification testing, and project planning will betracked. The in situ grouting for long-term disposal and for stabilization and retrieval treatability studywill include estimates of capital and operating costs and field remediation expenses based on expendituresfor the treatability study. The cost assessment will include evaluation of difficulties associated with thetechnology, reliability, and potential for schedule delays. Based on application assumptions derived fromfield demonstrations, individual cost factors will be estimated for the remediation of the SDA. The groutemplacement subcontractor and grout developers will provide input to this cost estimate. Site operationalfactors and verification and monitoring costs will also be considered for this cost estimate evaluation.

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5. EQUIPMENT AND MATERIALS

5.1 Required Equipment and Materials Long-Term Disposal

As presented in Section 4.1, the treatability study for long-term disposal will be conducted in threetesting phases: (a) bench testing, (b) implementability testing, and (c) field testing. Each of these testingphases has different equipment and material requirements. These requirements are described in thefollowing subsections.

5.1.1 Required Equipment and Materials for Bench Tests

Bench testing will be performed by an offsite laboratory (to be determined).for sample preparation and analysis will be provided by the INEEL M&O contractolaboratory services meet data quality requirements, contracting documentation willthe INEEL SMO. All analytical equipment and testing materials used in the benchby the offsite laboratory facility.

Testing requirementsr. To ensurebe coordinated withtests will be provided

The required equipment and materials for the bench tests include, but are not limited to, thefollowing:

Instrumentation (supplied by INEEL M&O Contractor)

• Isothermal gas chromatograph with flame ionization detector

• Temperature sensors with dataloggers.

Materials

• Grout mixtures

TECT

WaxFix

Krystal Bond

Tank reducing grout

Salt Stone

Vendor grouts (potentially).

• Simulated waste mixture

• INEEL soil

• Simulated waste forms (Series-743 mix)

2,680 mL carbon tetrachloride

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740 mL TCE

740 mL PCE

5,130 mL Texaco Regal Oil, R&O 68

4,120 g calcium silicate

620 g Oil Dri.

• Nitrate salts

Sodium nitrate

Potassium nitrate.

• Grout mixes

Grout/nitrate mixes

Grout/organic sludge mixes

Grout/strontium carbonate mix

Grout/INEEL soil.

• Sample Sets

Data acquisition system

Electrical power for bench system.

Detailed information on the equipment and materials to be used for the simulated bench tests willbe described in the In Situ Grouting Treatability Study Test Plan.

5.1.2 Required Equipment and Materials for lmplementability Testing

A jet-grouting vendor and grout material supplier will perform the implementability tests at soilconditions similar to the SDA. Equipment and materials for the intermediate tests include, but are notlimited to, the list provided below. Detailed information on the equipment and materials to be used forthe implementability testing will be described in detail in the In Situ Grouting Treatability Study TestPlan.

• Vendor test pit (supplied by jet-grouting vendor)

• Instrumentation (supplied by the INEEL M&O contractor)

Temperature sensors with dataloggers.

• Grouting equipment (supplied by jet-grouting vendor)

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Jet-grouting/drill system equipped with rotopercussion capabilities

Positive displacement pump

Transfer pump

Flow totalizer meters

Grout mixing facility.

• Materials

- Grout mixtures

- INEEL soil.

• Heavy equipment (supplied by jet-grouting vendor)

Backhoe

Forklift.

• Field equipment (suppl ed by the INEEL M&O contractor)

Tape measure

Camera

Logbooks.

5.1.3 Required Equipment and Materials for Field Tests

The jet-grouting vendor will perform the field test portion of the treatability study at the INEEL ona simulated pit south of the SDA. Equipment and materials for the field test include, but are not limitedto, the list provided below.

• Field test pit and simulated waste forms (supplied by the INEEL M&O contractor, see Section4.1.3.1)

• Instrumentation (supplied by the INEEL M&O contractor)

Temperature sensors with dataloggers

Field permeability testing (TBD)

High-volume air samplers.

• Grouting equipment (to be supplied by jet-grouting vendor)

Jet-grouting/drill system equipped with rotopercussion capabilities

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Positive displacement pump

Transfer pump

Flow totalizer meters

Grout mixing facility

Contamination control hardware.

• Materials to be supplied by jet-grouting vendor

Grout mixture.

• Heavy equipment (supplied by INEEL M&O contractor)

Backhoe

Forklift

Crane

Front-end loader

Dump trucks

Water supply tank and hoses

Cleanout water truck

Air compressor

50-kW generator

Thrust block

Weather structure.

• Field equipment (supplied by INEEL M&O contractor)

Permeability testing equipment

Tape measure

Camera

Logbooks

Shovels, picks, brooms

Buckets

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Spill prevention kits

Total survey station

Sample containers

Shipping forms and labels

Coolers with packing materials

Black marking pens

Parafilm

Absorbent paper wipes

Clear tape

Deionized water spray bottles

Plastic sheeting

Blotter paper

Plastic trash bags

Latex gloves.

5.2 Required Equipment and Materialsfor Confinement During Retrieval

As presented in Section 4.2, the treatability study for confinement during retrieval will beconducted in three phases: (a) bench testing, (b) implementability testing, and (c) field testing. Each ofthese testing phases has different equipment and material requirements. These requirements are describedin the following subsections.

5.2.1 Required Equipment and Materials for Bench Tests

Bench testing will be performed by an offsite laboratory (to be determined). Testing requirementsfor sample preparation and analysis will be provided by the INEEL O&M contractor. To ensurelaboratory services meet data quality requirements, contracting documentation will be coordinated withthe INEEL SMO. All analytical testing equipment used in the bench tests will be provided by the offsitelaboratory facility. The required equipment and materials for the bench tests include, but are not limited,to the following:

Instrumentation (supplied by INEEL M&O contractor)

• Temperature sensor and data logger

• Light photometer (e.g., Fisher Electro Photometer/Double Beam Colorimete or equivalent).

5-5

Materials

• Grout mixture

• Boron additive.

Detailed information on the equipment and materials to be used for the bench tests will bedescribed in the In Situ Grouting Treatability Study Test Plan.

5.2.2 Required Equipment and Materials for lmplementability Tests

A jet-grouting vendor and grout materials supplier will perform implementability tests at soilconditions similar to the SDA. This phase will be planned and executed at the same time as theImplementability Test Phase for Long-Term Disposal. All equipment for this phase are the same as forLTD. The paraffin grout will be supplied by a specialty vendor contracted to the jet-grouting vendor.

5.2.3 Required Equipment and Materials for Field Testing

The jet-grouting vendor will perform the field testing portion for the treatability study at the INEELon a simulated pit south of the SDA. This phase will be planned and executed at the same time as theField Testing Phase for Long-Term Disposal. Except for field permeability testing, all other equipment isthe same as for LTD. The paraffin grout will be supplied by a specialty vendor contracted to thejet-grouting vendor.

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6. SAMPLING AND ANALYSIS

This section addresses the sampling and analyses that will be conducted to support both of thegrout applications described in the in situ grouting treatability study. The two applications are:

• Long-term disposal

• Confinement during retrieval.

This section will provide general sampling and analysis details specific to the two groutapplications. A test plan will also be prepared by LMITCO that will describe in detail the testingprotocols, and sampling and analytical methods. Specific data quality objectives will be defined in thetest plan based on the test objectives and experimental design described in this work plan. The analyticallaboratory that will perform all activities shall be approved by LMITCO' s SMO, from both a quality andtechnical standpoint. The applicable documents that will provide the requirements for sampling andanalysis are as follows:

• In Situ Grouting Treatability Study Test Plan

• Addendum to Work Plan (DOE/ID-10622)

• Work Plan for Operable Unit 7-13/14 Waste Area Group-7 Comprehensive RemedialInvestigation/Feasibility Study (Becker et al. 1996)

• The current list of SMO-approved analytical laboratories

• Historical and analytical data from past waste characterization activities at the SDA

• Addendum to the Work Plan for the Operable Unit 7-13/14 Waste Area Group-7Comprehensive Remedial Investigation/Feasibility Study (DOE-ID 1998)

• Analytical results from INEEL documents relating to grouting activities at the INEEL.

Specific details relative to required sampling and analysis documentation will be provided in theIn Situ Grouting Treatability Study Test Plan.

The following sections list sampling and analysis requirements for bench, intermediate, andnonradioactive field testing for both treatability studies. Minimum detection limits to be set for eachanalysis will be included in the In Situ Grouting Treatability Study Test Plan.

6.1 Sampling Objectives

The objectives of the treatability study are to obtain data validating the implementability andeffectiveness of the in situ grouting technology. Specific test objectives have been defined for both thetreatability study applications and are presented in Section 3.

The objective of the in situ grouting treatability study is to provide sufficient data to evaluate thetechnologies as buried waste treatment for long-term in situ stabilization/disposal and confinement/stabilization during retrieval at the SDA. The sampling and analysis requirements for each treatabilitystudy are described in the following two sections.

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6.2 In Situ Grouting Long-Term Disposal

The three phases of testing for the long-term disposal treatability study are as follows:

• Long-Term Disposal Phase I—Bench Testing. Data will be collected to evaluate the wastematrix compatibility and performance to select candidate grout formulations for fieldapplication (see Section 4.1.1.1 for a detailed description of this activity).

• Long-Term Disposal Phase II—Implementability Testing. Data will be collected to evaluatehow the jet-grouting process is affected by grout properties (see Section 4.1.1.2 for a detaileddescription of this activity).

• Long-Term Disposal Phase III—Field Testing. Data collection activities will involve theevaluation of a field test of a grout material at an established clean nonradiological andnonhazardous test site which simulates conditions expected at the SDA (see Section 4.1.1.3 fora detailed description of this activity). Sampling and analysis will focus on assessing theimplementability and effectiveness of the in situ grouting process for long-term stabilization.

Each phase has specific sampling and analysis requirements to support data collection activities.Bench studies will involve the mixing of the 5 grout materials to provide physical and chemical data ofgrout properties to select materials for field testing. The implementability testing involves theintermediate testing of acceptable grout materials to provide significant information concerning theinjection properties and development of grout columns to support remedial design. Information fromthese two phases will feed into phase three, the field testing that provides data for evaluation of theimplementability, effectiveness, and costs for the in situ grouting remedial application. Information fromthe field testing will provide direct input data to support the risk model of the OU 7-13/14 feasibilitystudy.

6.2.1 Sampling and Analysis for Bench Testing

Test specimens will be prepared to determine which grouts are viable candidates for in situgrouting application. As described in Section 4.1.1.1.1, the first task will involve preparation of samplesto evaluate the effect of simulated waste on properties of grout; and this will be conducted at establishedviscosity settings (water contents) for grout injection. The only quantitative analysis will be ameasurement of the compressive strength. All samples will be qualitatively examined for curing andsetting properties, as presented in Section 4.1.1.1.2. Unacceptable samples will be eliminated fromfurther testing.

Standardized test specimens that pass the screening will be prepared. These specimens will besubjected to a series of physical and chemical tests. As presented in Section 4.1.1.2, these tests will beperformed to acquire data to evaluate the (1) rate of grout dissolution, (2) hydraulic properties,(3) implementability factors, and (4) chemical buffering capacity. Four sample sets will be prepared.

Grouts will be mixed at the maximum waste loading concentration for the various interferenceswhich produces a high-quality stabilized specimen. In addition to the interference samples, neat groutsamples will be prepared by mixing the grouts with a 1 wt% of strontium carbonate. This sample set willbe analyzed using the Accelerated Leach Test to assess the dissolution rate of the grout components fromthe test specimen. Test data will be used to rank the grouts and select the most appropriate materials forfield studies. Testing requirements are listed in Table 6-1. These test methods are described inSection 4.1.1.2.

6-2

Table 6-1. Test methods.

Data Usage

Hydraulic control

Implementability

Test

Hydraulic conductivityPorosityShrinkageTensile strength

Compressive strengthDensityFree water

Chemical buffering Oxidation-reduction potentialHydrogen ion activity

Microencapsulation Total VOCs in solids

Grout dissolution Accelerated Leach Test

Test Method

ASTM D-5081-90ASTM C-642-90ASTM C-827-87ASTM C-496-90

ASTM C-39-96ASTM D-695-91Instrument specificationsQualitative measurement

ASTM D-1498-76ASTM D-1293-84

SW 846-8260

ASTM C-1308-95

6.2.2 Sampling and Analysis for lmplementability Testing

Details concerning data collection activities for implementability testing are presented inSection 4.1.2. Neat grout samples will be the only samples collected during this testing phase. They willbe collected for measuring fluid viscosity to validate that mixture specifications are met. Suppliedmixtures falling outside the acceptable specification range will be rejected and either corrected or newload prepared. Confirmation testing will be required before acceptance of new or corrected loadmixtures. Viscosity will be measured using a funnel viscometer according to the API ProcedureRP-13B-1.

After grout emplacement, cure temperature of the emplaced field trials will be measured followingprocedures presented in Section 4.1.2. Data will be used to produce a curing profile for the grout materialand compared with previous and historical measurements.

Qualitative observations and quantitative measurements will be taken during grout emplacement(see Section 4.1.2). Qualitative and quantitative data will be collected to evaluate the colunmdevelopment. These data collection activities are described in Section 4.1.2.

6.2.3 Sampling and Analysis for Field Testing

Field testing will consist of using the final grout selected for the actual jet-grout application at thesimulated test site. Sampling and analysis from this phase of the project will primarily focus onevaluation of the implementability (contamination control issues) and effectiveness of the chosen grout tostabilize simulated waste conditions at the SDA.

6.2.3.1 Grout Emplacement. During grout emplacement, sampling activities will include fluidmeasurements and contamination monitoring (spread of the terbium oxide tracers). Neat grout sampleswill be collected initially from the concrete mixer or batch plant prior to initiating the field grouting.Testing will be performed using Standard ASTM methods as presented in Section 4.1.3.1 for viscosityand density. Field measurements will be used to verify that the fluid viscosity is within the acceptablerange, as determined by the implementability testing. Mixtures falling outside this specification rangewill be rejected and require correction before acceptance for field emplacement.

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Contamination monitoring for spread of tracers will include collecting data to evaluate theperformance of the contamination control equipment. Testing procedures for these sampling activities arepresented in Section 4.1.3.3. Rare-earth tracer spread will be evaluated during grouting activities usingsmears, high-volume filters, and solid samples of grout retums. All these samples will be evaluated by anICP-MS laboratory for the tracer materials present.

During the grouting process, the following operation data will be recorded to evaluate theimplementability of the in situ grouting technology:

• Time to grout




• Volume increase


6.2.3.2 Postgrouting Evaluation. After grout emplacement, quantitative and qualitative data willbe collected. The data collection activities will focus on the evaluation of the stabilization properties ofthe grouted waste. Data collection activities will include:

1. Measuring cure temperature of the monolith

2. Measuring hydraulic conductivity of the monolith

3. Destructive examination and sampling of the monolith.

6.2.3.2.1 Hydraulic Conductivity—The simulated waste inside the test pit will be groutedto produce a monolithic structure. After emplacement, the in situ temperature of the monolith will bemeasured to ensure that the set temperature has been reached before proceeding to the hydraulicconductivity testing. Methods for hydraulic conductivity testing will be determined after researchingapplicable field permeability methods. Field testing procedures will be presented in detail in the In SituGrouting Treatability Study Test Plan.

6.2.3.2.2 Destructive Examination Sampling—After completion of the hydraulicconductivity testing, the test pit will be excavated for examination and sampling of the monolith.Procedures for examination of the monolith are presented in Section 4.1.3.4.3. During the destructiveexamination, detailed observations will be made of the quality of the grouted waste forms and internalintegrity of the monolith. The monolith will be examined for:

• Grout permeation (ratio of grout to soil to waste)

• Degree of bonding between grout and waste

• Monolith cracking and fracturing

6-4

• Areas of set retardation and impeded curing

• Zones of incomplete mixing or component separation

• Areas of monolith swelling and disintegration.

The monolith will be sectioned into quadrants for interval sampling. Testing requirements arelisted in Table 6-2. Section 4.1.3 provides a more detailed discussion of these testing methods.

Test results from monolithic sampling will be compared with bench-test results to evaluate physicaland chemical effects due to the high-pressure mixing with soil and waste. Hydraulic conductivity valuesfrom the monolithic samples will be compared with hydraulic conductivity results from the fieldpermeability testing to evaluate laboratory versus field measurements.

6.3 Confinement During Retrieval

Sampling and analysis needs for the confinement during retrieval will involve three phases oftesting as follows:

• Confinement During Retrieval Phase I—Bench Testing. Data will be collected to evaluateeffects of the boron additive on physical properties of the paraffin-based grout. Bench testswill also be performed to evaluate baseline data on emissions of VOC waste constituents andBtu content.

• Confinement During Retrieval Phase II—Implementability Testing. Data collected from theintermediate testing will be used to assess the implementability of jet grouting the paraffin-based grout with the boron additive.

• Confinement During Retrieval Phase III Field Testing. Data from the field testing will beused to evaluate the effectiveness of the paraffin-based grout for dust suppression and controlof the spread of tracers. Effects of the buried simulated wastes on monolith development andexcavation procedures will be determined.

Specific sampling and analysis requirements are described in the following subsections.

Table 6-2. Testing requirements for monolith samples from the long-term disposal study.

Data Usage Test Test Method

Grout dissolution Accelerated leach test ASTM C-1308-95

Hydraulic properties Hydraulic conductivity ASTM D-5084-90Tensile strength ASTM C-496-90Porosity ASTM C-642-90

Chemical buffering PH EPA Method SW-9045Redox potential EPA Method SW-9045

lmplementability Compressive strength ASTM C-39-96Density Instrument specifications

Unsaturated flow Moisture-capillary ASTM D-3152-72

Contaminant stabilization Nitrates EPA Method 300

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6.3.1 Sampling and Analyses for Bench Testing

Standardized samples will be prepared for bench testing to assess the following:

• Optimum concentration of boron/glycerin additive

• Btu analysis

• Cooling temperature profile

• DOT oxidizer test.

Details concerning these testing methods and procedures are presented in Section 4.2.1.

6.3.1.1 Boron Additive Effects on Grout. Bench testing for evaluation of boron effects on theparaffin-based grout will involve preparing a solution of boron/borate and glycerin that will be dyed darkred or other suitable color. Four samples and applicable replicates of paraffin will be prepared in beakersor test tubes (photometer sample tubes). One set will be of neat paraffin with no additive for the control.The samples will be tested for light absorption by photometry, which will determine if the glycerin(boron) is dispersed throughout the paraffin.

6.3.1.2 Cooling-Temperature Profile. Temperature measurements will be collected over timefor samples of neat paraffin with no additives and paraffin with boron/borate additive to develop a coolingprofile. These data will be compared with similar results from previous investigations as an indicator ofeffects of additives on grout behavior.

6.3.1.3 Btu Analysis. Subsamples will be collected from bench tests of grout/boron additionsamples and sent for analysis of Btu content according to ASTM D240/D 3286, Heat of Combustion. Thedata will be compared with published Btu content data and used in evaluating potential ex situ treatmentoptions for the contained waste such as incineration.

6.3.1.4 DOT Oxidizer Test. The DOT oxidizer test will be performed on prepared samples ofparaffin grout and nitrate salts at salt loadings of 12, 25, 50, and 75 wt%. Testing will be performedaccording to 49 CFR 173.127. This test is for information only and will be used to assess transportationof retrieved material.

6.3.2 Sampling and Analyses for lmplementability Testing

Sampling and analysis requirements for implementability testing will follow the testing methodsand procedures for long-term disposal. The major difference between these testing programs is that theconfinement during retrieval will involve the field implementation study of the paraffin-based grout withthe boron additive. Data will be evaluated to determine, if any, modifications are required to the groutformulations to optimize the jet-grouting and stabilization process.

6.3.3 Sampling and Analyses for Field Testing

Data from the field testing will be used to evaluate dust suppression and effects of the simulatedwastes buried in the Cold Test Pit on monolith development and excavation procedures. Monolithicsamples will be collected for Btu analysis. Other data collection activities will follow procedurespresented in Section 4.1.3 and include (a) grouting and operational factors, (b) contamination controlperformance monitoring, and (c) curing temperature of the monolith.

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6.3.3.1 Evaluation of Dust Suppression During Monolith Excavation/Retrieval. Duringexcavation and retrieval of the monolith, rare-earth tracers and aerosolized dust will be monitored in theair at the dig face, in the breathing zone of the workers, and with high-volume filters in the weatherstructure. Smear and solid samples also will be collected from the monolith during excavation forrare-earth tracer analysis.

6.3.3.2 Btu Content Analysis. Monolith samples will be collected for analysis of Btu contentaccording to ASTM D240/D 3286, Heat of Combustion. The data will be compared with published Btucontent data and used in evaluating potential ex situ options for the contained waste such as incineration.

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7. DATA MANAGEMENT

Data generated during testing will be managed in accordance with guidelines provided in the DataManagement Plan for the INEEL Environmental Restoration Program (INEL 1995c). This plan providesor references procedures and requirements necessary to develop a database of relevant information thatcan be readily accessed and accurately maintained. The plan describes the data flow process, datacustodianship, and organizational and individual responsibilities associated with data management. Theplan also provides the project file and reporting requirements and identifies database capabilities requiredto allow selective data sorting, analysis, formatting, and reporting.

The Data Management Plan provides the necessary requirements for the treatability study. Therewill, however, be some deviations from the plan. Deviations are due to information not directly recordedin logbooks or from laboratory data not tracked by the Environmental Restoration Information System.For the treatability study, a majority of the measurements and information will be recorded on data sheetsthat need to be included in the final data package to be sent to the INEEL at the project conclusion. Thefollowing tests will result in information considered to be deviations from the Data Management Plan:

• Any data not tracked in the Environmental Restoration Information System and not recordedin field notes.

Information that deviates from the Data Management Plan will be placed in the AdministrativeRecord and Document Control. Additionally, hard copies of raw data and test results will be summarizedin the final treatability study report. Specific data quality objectives and data validation requirements (asnecessary) are specified in the Sampling and Analysis section (Chapter 6). Use of Program RequirementsDocument (PRD)-111, "Records and Forms Management," will ensure that information is availablewhen needed. MCPs will be invoked during this treatability study process for activities performed at theINEEL. The primary MCPs that will be used are:

• MCP-205, "Records Management"

• MCP-230, "Environmental Restoration Document Control Center Interface"

• MCP-231, "Logbooks"

• MCP-240, "Internal/Independent Review of Documents"

• MCP-328, "Test Plans"

• MCP-452, "Treatability Stud es."

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8. DATA ANALYSIS AND INTERPRETATION

Data will be summarized and evaluated to deterrnine the validity and performance of the treatmentprocess after the testing phases of in situ grouting are complete. One goal of this evaluation will be todetermine the quality of the data collected. A11 quantitative data will be checked to assess precision,accuracy, and completeness. If the quality assurance objectives are not met, consensus on a path forwardwill be sought with the 1NEEL M&O contractor, DOE-ID; EPA Region 10; and Idaho Department ofHealth and Welfare (IDHW).

8.1 Data Reduction for All Tests

All data reduction will be completed as specified in the analytical method or procedure. Wheredata reduction is not computerized, calculations will be performed in permanently bound notebooks or onpreprinted data reduction pages. The data reduction for some analyses includes analyst interpretations ofraw data and manual calculations. The analyst interpretations will be written in ink on the raw data whenthis is required. Corrections will be made as necessary and documented and dated in ink on the originalsheets.

8.2 Data Validation for All Tests

Data validation begins with the sample collector, analyst; or data collector and continues until thedata are reported. The individual analysts will verify and sign for the completion of the appropriate dataforms to verify the completeness and correctness of data acquisition and reduction. The in situ groutingprincipal investigator will review the computer and manual data reduction results and inspect laboratorynotebooks and data sheets. These actions will be taken to verify data reduction correctness andcompleteness and to ensure close adherence to the specified analytical method protocols. Calibrationsand quality control (QC) data will be examined by the individual analysts to verify that all instrumentsystems are in control and that quality assurance objectives for precision, accuracy, completeness, andmethod detection limit are being met. Specific designation as to the INEEL M&O contractor validationlevel for each piece of data will be included in the treatability study test plan.

Principal criteria that will be used to validate the integrity of data during collection and reportingare as follows:

• Verification that chain-of-custody procedures have been followed (where applicable)

• Verification by the project analyst that all raw data generated for the project have beenstored on disk and or hard copy and that storage locations have been documented

• Examination of the data by the in situ grouting principal investigator or data reductionpersonnel to verify adequacy of documentation.

Outliner data are defined as QC data lying outside a specific QC objective window for precision oraccuracy for a given method. Should QC data be outside control limits, the principal investigator willinvestigate the potential causes of the problem. Data will be flagged with a data qualifier.

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8.3 Procedures for Assessing Data

8.3.1 Notation

Measurements collected during the treatability study are intended to determine properties ofmaterials. More precisely, the variance and bias of the measurement process are to be estimated. Thevariance and bias correspond to the precision and accuracy, respectively, of the measurement processes.

Let M denote a measurement and let 62meas denote the variance of the measurement process. If nmeasurements are taken, denote them by and denote their average by Mavg. The sample variance shallbe defined as:

s'meas = [1/(n-1)1E,(1A-M„g)2.

The sample variance s2,,,„, will be used to estimate the variance of the measurement process &ragas

Each measurement is intended to measure some true value, T. The bias, B, is defined as thedifference of the long-term average measurement and the true value. Man approximates the long-termmeasurement, but is not exactly the same because Man only involves n measurements. The true value isknown, approximately, in a test situation. Therefore, the bias B can be estimated in a test situation by:

= Mavg - (approximation of true value).

8.3.2 Estimation of the Variance of the Measurement Process (a2meas)

The sample variance, s2„,,a, is an unbiased estimator of a2„,e„, that is s2 estimates a2 with perfectaccuracy. Consider now the precision of s2. Assuming that the measurements are independent andnormally distributed, a 95% confidence interval for 62 is:

(n-1) s2a120,975 6 < (n-1) s /ET2- --2o.o2s

where 17120,975 is the 97.5th percentile of a rf

Distribution with n-1 degrees of freedom and 1120 05 is the 2.5th percentile. If n = 5, this intervalbecomes:

4 s2/1 1.1 02 4s/0.484

0.36 s2 a2 8.26s2

So that 62 is within a factor of 10 of s 2, as required by the data quality objectives. Therefore, a iswithin a factor of 3 of s.

8.3.3 Estimation of Bias

The tests will be set up so that the approximation of the true value of a measurement is an unbiasedestimate of the true value. That is, any one approximation may be too high or too low, but the averageover many possible setups is the true value. The variance of the approximation to the true value isdenoted 6tme, and must be estimated by knowledge of the test setup. For example, if the true value is thetemperature of the treated mass, contributors to a2,,,„ would include measurement error in recording the

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measured value (probably negligible). The magnitude of the error must be estimated by considering thenature of all contributors.

The bias B is estimated by using n as defined above. Because Man is an unbiased estimator of thelong-term average measurement, and the approximation of the true value is assumed to be an unbiased

estimator of the true value, it follows that )13‘ is an unbiased estimator of B, that is, n has perfect accuracy.

Regarding precision, the variance of n

var(n. ) = var (m„g) + var(approximation of the true value) = 62,,,eas/n +

The standard deviation is defined as the square root of the variance of the measurements (n ) or

VO-2mealn 0-2true •

8.4 Data Analysis and Interpretation to Support Long-Term Disposal

Data from the long-term disposal treatability study will be used to support test objectives presentedin Section 3.1. As previously stated, the long-term disposal study will be conducted in three phases:(a) bench testing, (b) implementability testing, and (c) field testing. The bench and implementability testswill provide data to assist with selecting a grout and defining operating parameters for field application.Bench tests will also provide data for later verification of the field tests and also provide data for the riskmodel as part of the evaluation of remedial alternatives for the OU 7-13/14 feasibility study. Each testphase has specific testing objectives that are supported by the testing strategy presented in Section 4.1.Data analysis and interpretation for each of these phases are presented in the following subsections.

8.4.1 Data Analysis and Interpretation for Bench Tests

For long-term disposal bench tests, both qualitative and quantitative data will be obtained from thecharacterization testing that will be performed. Data from these tests will be used to screen and selectgrouts for further field testing. The long-term disposal bench testing is separated into two tasks: an initialscreening evaluation and a more thorough physical and chemical evaluation of the grouts. The screeningtask will evaluate all five candidate grouts and screen out those that lack the desired cure temperatureproperties. Grouts that pass the temperature criteria will then be subjected to additional screening andgrouts showing acceptable qualitative properties will be subjected to quantitative and qualitativeevaluation. The final selected grouts (a minimum of two grouts will be retained) will then be used in theimplementability testing phase (see Section 8.4.2).

8.4.1.1 Bench Tests to Evaluate Waste lnterference Tolerance, Curing, and VOCRetention Temperature. The long-term disposal bench tests will involve obtaining data from eachgrout at optimum viscosities with varying percentages of interferences (i.e., nitrate salts, organic sludgesimulant, and soil) as discussed in Section 4.1.1.1.1. Curing temperature will be measured usingtemperature sensors connected to a portable data logger for a subset sample of each grout/interferencemixture. The temperature profiles of grout-interference combinations will be evaluated on a pass-failbasis with the acceptance criteria based on whether the grout exceeds 100°C at any time. Combinationsthat pass this test will be evaluated qualitatively for grout properties (cracks, fractures, set retardation,incomplete mixing, component separation, swelling, and disintegration). Grout samples failing thistemperature threshold will be dropped from the evaluation process.

Evaluation of the effects of waste loading on grout samples will also be conducted. Test specimenswill be prepared with soil, organic sludge, and nitrate salts added to the grout at concentrations of 12, 25,

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50, and 75% by mass. Samples will be qualitatively examined for curing and setting problems (i.e.,cracks, fractures, set retardation, incomplete mixing, component separation, swelling and disintegration).Sample examination will also be used to determine the maximum tolerable waste concentrations that stillcan produce a properly cured sample. These waste loading concentrations will be used to determinegrout-waste formulation implementability testing.

Solid specimens from the organic sludge tests and a control sample of 100% sludge simulant willbe used to determine VOC content after the samples have been allowed to cure. The samples will beanalyzed by standard batch leaching techniques (ASTM C-I308-95). Concentrations of targeted organicconstituents (i.e., carbon tetrachloride, tetrachloroethylene, and trichloroethylene) will be determinedusing EPA-approved methods (SW846 6010B or equivalent). Data will be used to determine the quantityof targeted VOCs remaining in the grout specimens and the loss to volatilization. Results may be used tosupport the risk assessment for the OU 7-13/14 feasibility study.

8.4.1.2 Bench Tests to Evaluate and Rank Grouts for Field Testing. Grouts that pass thescreening previously described will be further subjected to physical and chemical testing. Grout to wasteformulations (interferences) to be further tested will be determined by results of the qualitative evaluation.Samples of compatible grout mixtures will be prepared according to mix formulas supplied by the vendoror as specified in the literature. Four sets of samples will be prepared for the characterization testing.These samples will be subjected to a series of physical and chemical tests as presented in Section 4.1.Test specimens will be prepared in the following combinations: (a) grout/soil, (b) grout/organic sludge,(c) grout/nitrate, and (d) grout/strontium carbonate. Grout/organic sludge, grout/soil and grout/nitratesamples will be prepared at the optimum viscosity, maximum acceptable organic sludge loading,maximum acceptable soil loading, and maximum acceptable nitrate salt loading, respectively.Grout/strontium carbonate samples will be prepared by adding 1 wt% by mass of strontium carbonate andsubjected to accelerated leach testing to assess the rate of dissolution of the grouts.

The test matrix will include analysis of hydraulic properties (e.g., porosity, shrinkage, and tensilestrength), implementability factors (e.g., viscosity), and chemical properties (e.g., oxidation-reductionpotential and pH). Qualitative assessments such as assessing production of free water will also be made.Test data will be used to rank the grout formulations for selecting mixtures for field testing.

Each criterion has a relative priority in the selection of the grout formulations to be taken to thefield. Grout dissolution and hydraulic control have the highest priority; implementability will be assignedsecondary importance in selecting a grout. Chemical buffering will be assigned tertiary importance inselecting a grout.

8.4.2 Data Analysis and interpretation for lmplementability Testing

Implementability testing will involve a limited series of field trials. This study will evaluate theemplacement process to determine if grout properties adversely affect the implementability and alsoconfirm that the monolith design will be met. Test results will provide data on the implementability ofthe material for jet-grouting application, cure temperature, and grout column development.

Field trial emplacement will be conducted in soil conditions similar to the SDA. Major equipmentrequirements and test pit construction are presented in Section 4.1.2. The jet-grouting/drill-rig system,support equipment, and testing arrangement planned for the field tests will be used. A batch plant willprepare and mix the grouts for emplacement. At least two batch samples of the grout mixtures will becollected and measured for viscosity following ASTM standards. Viscosity measurements will be used toverify that the mixture meets fluid specifications. Loads testing outside the acceptable range will berejected and require reconditioning until specification requirements are met.

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Three field trials will be grouted for each grout mixture. Information provided by this effort willinclude both quantitative and qualitative data for grouting parameters (i.e, injection pressure, step rate,step distance, rotation rate, and grouting interval). All observations will be recorded in the principalinvestigator's and the field team leader's logbook. Information from field observations will focus ondetermining whether the grout is injectable. The following operational data will also be collected:(a) mixing problems such as excessive air entrainment, suspended solids and materialseparation; (b) equipment fouling, filter caking, and residual buildup inside drill stem, downholeassemblage, and pumping equipment; and (c) other unusual operational occurrences. During grouting,data will be collected of the volume of grout used to emplace the field trial. These data will be used toestimate the volume of grout that will be needed to meet monolith design for the field tests. Volume ofgrout returns will be also measured to provide information for thrust block design and contaminationcontrol requirements. Data collected during grouting will assist with setting grouting parameters for thefield tests.

After completion of the three field trials planned for each grout mixture, a temperature sensor willbe inserted into one trial for each successfully emplaced grout to measure curing temperature, followingprocedures presented in Section 4.1.2. Data will be used to evaluate the cure temperature of the field trialand will be compared with data from the bench tests. Data will also be used to confirm that the curetemperature is below 100°C. The maximum temperature of 100°C has been established as the cutoffpoint for use of any grout. This requirement was established as a safety precaution due to the possibilityof steam explosions during grout emplacement.

Field trials will be allowed to cure for 1 week and then exposed for examination using standardexcavating equipment (backhoe). Detailed field notes and photographs will be taken of the excavatedgrout column faces. In addition, incremental sections of the grout column will be removed to gather moredefinitive data. Information obtained from these activities will involve (a) evaluating nominal dimensionsof the grout columns including internal portions of the grout columns for completeness of mixing andgrout permeation, and (b) examining the columns for proper setting and column development.

After completion of this testing phase, the data generated will be used to select one grout materialfor field testing. The final section process will choose a grout that is (a) pumpable with minimaloperational problems, (b) returns minimal grout, (c) cures below 100°C, and (d) produces a grout columnwith a combination of maximum diameter and minimal soil inclusions.

8.4.3 Data Analysis and Interpretation for Field Test

The field testing will consist of using the final grout selected for the actual jet-grout application atthe simulated test site. Data analysis and interpretation from this phase will focus on evaluation of theimplementability and effectiveness of the chosen grout to stabilize simulated waste conditions at theSDA. The field test will include (a) designing and constructing a specially designed pit containingsimulated SDA and Pit 6 material, (b) grouting the simulated pit with the final selected grout mixture, and(c) conducting a post grout evaluation to evaluate the implementability and effectiveness of thetechnology for long-term waste stabilization.

8.4.3.1 Data Analysis and lnterpretation to Evaluate the Field lmplementability of InSitu Grouting Technology for Monolith Design Application. Before initiating grouting, neatgrout samples will be collected and tested using Standard ASTM methods as presented in Section 4.1.3.1for viscosity and density. Field measurements will be used to verify that the fluid viscosity is within theacceptable range, as determined by the intermediatc testing. Delivered grouts outside this specificationrange will be rejected and require correction before acceptance for emplacement.

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During grout emplacement, specific data will be recorded to evaluate the implementability of thegrouting application. These data will include evaluations and review of the jet-grouting apparatus; fieldoperations, grout mixing, and delivery logistics; contamination control equipment and measures; thrustblock stability and functionality; equipment troubleshooting measures; equipment laydown process; andtransfer operations from grout hole to grout hole. All test observations and field measurements will berecorded in logbooks by field personnel. Operational data that will be recorded to evaluate theimplementability of the in situ grouting technology includes:

• Time to grout




• Volume increase


8.4.3.2 Data Analysis and Interpretation to Determine the Extent of ContaminantRelease During Grouting. Contamination monitoring will include collecting data to evaluate theperformance of the contamination control equipment. Testing procedures for these activities arepresented in Section 4.1.3. Rare-earth tracer spread will be evaluated during grouting activities usingsmears, high-volume filters, and solid samples of grout retums. All samples will be analyzed by anICP-MS laboratory for the tracer materials. Test results will be used to evaluate the effectiveness ofcontamination control measures to prevent the spread of simulated contaminants. The results from thismonitoring will be used to assess short-term effectiveness of in situ grouting by converting theconcentration of rare-earth elements in the grout/water into projected concentrations of actualcontaminants using appropriate scaling factors. These values will be used to calculate expected workerexposure.

Contamination monitoring will provide data to evaluate the effectiveness of the engineered systemto allow bubble-suited entry in an actual operation and to provide adequate safety protection andminimize potential loss of equipment. Additionally, this information will be used to define the degree ofdecontamination required for grouting equipment for full-scale application at the SDA. The intended useof these data is for assessing short-term effectiveness of contamination control measures.

8.4.3.3 Data Analysis and interpretation to Evaluate Hydraulic Properties of theEncapsulated Waste Form. Hydraulic conductivity is a measure of the resistance of a material to thepassage of water. Permeability tests will be performed to estimate the quantity and flow rate of waterthrough the monolith under saturated conditions. The permeability of a stabilized waste is an importantfactor, as it indicates the ability of a material to permit the passage of water and to limit the loss ofcontamination from the stabilized waste to the environment. Several field permeability testing methodswill be researched to select the most appropriate procedures for deployment. Section 4.1.3.2 describes indetail the relevance of permeability as it relates to this activity. Hydraulic conductivity values obtainedby this method are critical input parameters for the evaluation of risk reduction by this technology.

Field hydraulic conductivity studies will estimate the quantity and flow rate of water through themonolith. Several other tests (e.g., tensile strength, porosity, and unsaturated flow) will also be

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performed on systematic monolith samples to assess hydraulic properties that could influencepermeability and potentially cause an increase in contaminant leaching from the monolith. Monolithsamples will also be tested in the laboratory for hydraulic conductivity and compared with valuesobtained from the field studies

Data will be used to determine the ability of the monolith to eliminate, reduce, or control site risksassociated with mobility of contaminants by reduction of permeability. Baseline data obtained from thebench testing will be compared with field results to assess effects to the grout properties as a result ofhigh-pressure injection into the soil/waste matrix. Test results will be used to support the risk assessmentmodel of the OU 7-13/14 feasibility study.

8.4.3.4 Data Analysis and Interpretation to Evaluate the Quality and Integrity of theMonolith and Encapsulated Waste Forms. After completion of the hydraulic conductivity testing,the monolith will be excavated for examination and sampling. Procedures for examination of themonolith are presented in Section 4.1.3.3. During the destructive examination, detailed observations willbe made of the quality of the grouted waste forms and internal integrity of the monolith. During thedestructive examination, the monolith will be examined for (a) grout permeation (ratio of grout to soil towaste), (b) degree of bonding between grout and waste, (c) monolith cracking and fracturing, (d) areas ofset retardation and impeded curing, (e) zones of incomplete mixing or component separation, and (t) areasof monolith swelling and disintegration. The data will be used to validate the success of the emplacementprocess to encapsulate the buried waste and produce a monolithic structure.

8.4.3.5 Data Analysis and Interpretation to Estimate Longevity and Chemical BufferingCapacity of the Monolith. Samples will be collected from the grouted waste forms and analyzed bythe Accelerated Leach Test and for oxidation/reduction and pH measurements. Procedures for sampletesting are presented in Section 4.1.3. Accelerated leach testing will provide information of themonolith's chemical stability. The dissolution rate of the grout will be estimated from this data, which intum will be used to estimate the longevity of the treatment process or the time that the grout will bufferthe chemical properties of the groundwater and control dissolution and mobility of contaminants. Thesedata will be used to predict the ability of the monolith to resist degradation, maintain contaminantencapsulation, and control contaminant solubility.

Mobility of some contaminants (e.g., metals) are govemed by the pH and oxidation-reductionpotential of the micro-environmental by their effects on the solubility of the contaminants. The chemicalimmobilization of waste material by grout depends on one fundamental factor: the grout must convert thewaste into an insoluble form. The waste component can be chemically immobilized by severalmechanisms. It could be adsorbed onto phases in the grout or incorporated into the crystal lattice of aninsoluble phase, or it could form new insoluble compounds, etc. Regardless of the specific insoluble formof the waste component, its formation and stability depend on one or more interrelated chemicalproperties of the intergranular pore fluid. These properties include the oxidation-reduction potential (Eh),the acid-alkaline (pH) character, and the composition of constituents dissolved in the water. Theseproperties are controlled by either the grout or the natural conditions in the SDA.

The oxidation-reduction potential (Eh) is a measure of the energy required to add or subtract anelectron from a particular atom or ion. In the case of most metals, a "high oxidation state" is the state inwhich the ionic form of the metal has lost several electrons (e.g., three or four) and has acquired a positivecharge. A lower oxidation state of the same metal might have a positive charge of one or two. Anexample is iron: the high oxidation state has a positive three electronic charge, while the low oxidationstate has a positive two charge. Iron in the positive three-oxidation state is stable in air and is found asordinary rust. It is virtually insoluble in air-saturated groundwater. Iron in the positive two electronicstates is soluble in water. It is not stable in groundwater saturated with air, but it is stable in "reducing"

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condition, e.g., in the presence of decaying organic matter or similar material. In such an environment,iron would remain in the "reduce& state with a positive two electrical charge. Air and decaying organicmatter define the general limits of oxidation and reduction found in most groundwater systems. Theimportance of oxidation-reduction to waste containment arises from the fact that a given contaminant mayhave different solubilities, occasionally very greatly different, in different oxidation states. Thuschromium, technetium, etc., are soluble in groundwater saturated with air, which produces a "highoxidation state," but are virtually insoluble in groundwater having a low oxidation-reduction potential.Other elements are more soluble in a lower oxidation state, e.g., iron, manganese, etc. Many elements areunaffected by the range of oxidation states found in most natural systems, e.g., C, I, Ca, Si, AI, and manyothers. In general, the SDA groundwater found in the buried waste has a high natural oxidation-reductionpotential because it is at a shallow depth and saturated with air.

The acid-alkaline character of groundwater also plays a role in the immobilization of wastecomponents. It is described by the pH, a measure of the hydrogen ion concentration in water. The pH ofgroundwater affects the solubility of materials in a manner similar to oxidation-reduction. Manymaterials are more soluble in acidic groundwater, some materials are more soluble in alkalinegroundwater. For example, chromium and technetium are more soluble in very alkaline groundwater, buthave much lower solubility if the pH of the groundwater system is neutral. The solubility of somematerials such as iodine is virtually unaffected by the pH of most natural waters. The pH of thegroundwater in the SDA is alkaline, pH about eight, because the groundwater is saturated with themineral calcite, CaCO3, which acts as a natural pH buffer.

The composition of the material dissolved in the groundwater system also affects the behavior ofthe waste components. The SDA groundwater is saturated with the mineral calcite (CaCO3). Calcite isbeing precipitated by natural process in the SDA soils. Any additional calcium added to the groundwater,for example from chemical degradation of cementitious grout, will precipitate as calcite. The calciteincorporates carbon in its crystal lattice, including the radioactive waste component carbon-14.Strontium, including its radioisotopes, also tends to be concentrated in calcite because it is chemicallyvery similar to calcium.

The discussion above describes the primary variables that control the dissolution and precipitationof waste components in groundwater systems. In particular, the groundwater of the SDA has a highoxidation-reduction potential. It is equivalent to air and is buffered by it. The SDA groundwater has apH of about eight and is buffered by aqueous reactions involving calcite. The SDA groundwaters aresaturated with calcium and carbonate ions. These properties affect the chemical processes acting on thewaste components. Certain grout materials to be evaluated in bench studies will affect the chemicalproperties, thus solubility, of the contaminant materials. These materials will be evaluated along withthose nonreactive grout products.

Samples of the monolith will be tested for pH and oxidation-reduction potential (Eh) to determinethe speciation of metal constituents (including plutonium and uranium) and resulting solubility. Thisinformation, along with chemical and physical properties taken from scientific literature and the estimateddurability of the thrust block (as a cap) and of the monolith and their effects on water infiltration, will beused to develop a mathematical model to estimate the dissolution rate of the monolith and the diffusivityof the constituents. The resulting estimated dissolution and diffusion rates are direct input variable for therisk assessment model and will be used for calculation of the specific risk reduction as a function of time.

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8.5 Data Analysis and Interpretationof Bench Tests to Support Confinement During Retrieval

Data from the study of the confinement during retrieval alternative will be used to support the testobjective presented in Section 3.2. The bench testing and implementability testing provide data to assistin defining appropriate operating parameters to be used in field testing. Bench testing will also providedata along with field testing results for use in the risk model as part of the evaluation of remedialalternatives for the OU 7-13/14 feasibility study. Data analysis and interpretation for each of the threetesting phases are presented in the following subsection.

8.5.1 Data Analysis and Interpretation for Bench Testing

The bench tests for in situ grouting for confinement during retrieval are designed to:

• Determine the maximum concentration of boron compound that can be successfullyincorporated into paraffin-based grout achieving homogenous distribution without adverseeffects to monolith stability

• Determine cooling profiles for the neat paraffin-based grout (grout with no interferences oradditives), grout/boron, grout/sludge simulant, and grout/nitrate salts mixtures forcomparison with and evaluation of effects on monolith development

• Determine Btu content for the neat paraffin-based grout, and grout/boron, grout/sludgesimulant, and grout/nitrate salts mixtures for comparison

• Determine the status of DOT oxidizer testing for paraffin/nitrate mixtures.

8.5.1.1 Bench Test of Boron Addition to Grout. Data from the bench test on boron addition tothe paraffin-based grout will consist of the differences in light absorbance for a paraffin control sampleand samples of paraffin with addition of three concentrations of a boron/borate:glycerin solution. Theresults of the data will be used to determine the maximum concentration of the solution that can be addedwithout adversely affecting curing, cooling, or stability of the paraffin-based grout. With the solutiondyed a deep red color, distribution of the solution in the paraffin should be visible.

8.5.1.2 Bench Test to Measure Temperature of the Paraffin Monoliths to DevelopCooling Profiles. Data from the bench test to measure temperature of the CDR monoliths will consistof temperature readings taken over time. Temperature sensors will be inserted into monoliths of neatgrout, and grout/boron, grout/sludge simulant, and grout/nitrate salts mixtures prepared for other benchtests to measure temperature during material curing. A portable data logger will be attached to the sensorto record temperatures during this period.

Temperature data will be used to develop cooling profiles for the various grout mixtures forcomparison and evaluation of effects from the various additives (e.g., boron, organic sludge, nitrate salts)at different concentrations on monolith development and stability.

8.5.1.3 Bench Test of Btu Content of Paraffin-Based Grout. Data from the bench test todetermine Btu content will consist of published data of Btu content for paraffin and results from standardanalytical techniques (Heat of Combustion, ASTM D 240/D 3286) on samples collected. Samples will becollected from monoliths of neat grout, and grout/boron, grout/sludge simulant, and grout/nitrate saltsproduced from previously described bench tests and samples collected from the full-scale monolith duringexcavation.

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8.5.1.4 DOT Oxidizer Test. Testing will be performed using 49 CFR 173.127.

The Btu content data will be used in the development of postexcavation ex situ treatment options(especially incineration) for the feasibility study.

8.5.2 Data Analysis and Interpretation for lmplementability Testing for ConfinementDuring Retrieval Option

Implementability testing will involve a limited series of field trials. The study will evaluate theemplacement process to determine if the grout adversely affects injectability and confirm that themonolith design will be met. Test results will provide data on the implementability of the material for jet-grouting application, cure temperature, and grout colunm development under optimum conditions.

Emplacement during implementability testing will be conducted in soil conditions similar to theSDA. The jet-grouting/drill-rig system, support equipment, and testing arrangement planned for the fieldtests will be used. The vendor will prepare and mix the grout for emplacement.

Field trials will be grouted at several mixtures to determine optimal mixtures and temperature.Information provided by this effort will include both quantitative and qualitative data for groutingparameters (e.g., injection pressure, step rate, step distance, rotation, rate, temperature, and groutinginterval). All observations will be recorded in the principal investigator's and the field team leader'slogbooks. Other operation data will also be collected: (a) mixing problems such as excessive airentrainment; (b) equipment fouling, and residual buildup inside drill stem, downhole assemblage, and/orpumping equipment; and (c) other unusual operation occurrences. During the grouting operation, datawill be collected of the volume of grout used to emplace the field trial and the amount of grout retums.These data will be used to estimate the volume of grout that will be needed to meet monolith design forthe field tests. The volume of grout returns will also provide information for thrust block design andcontamination control requirements. Data collected during implementability testing will assist withsetting grouting parameters for the field tests.

The curing temperature of the grouted monoliths will be measured as described in Section 4.2.1.2.Data will be used to evaluate the cure temperature of the implementability trial and will be compared withdata from the bench tests and field tests.

Implementability trials will be allowed to cure for 1 week. Monoliths will then be excavated forexamination. Detailed field notes and photographs will be taken of the excavated grout colunm. Inaddition, incremental sections of the grout column will be removed to gather more definitive data.Information obtained from these activities will involve (a) evaluation of the nominal dimensions of thegrout columns including intemal portions of the column for completeness of mixing and groutpermeation, and (b) examination of the columns for proper setting and column development.

After completing the implementability testing, the data generated will be used to determineoptimum grouting parameters and for comparison with field testing results.

8.5.3 Data Analysis and interpretation for the Tests to Support the Confinement DuringRetrieval Option

8.5.3.1 Test of Contamination Control Monitoring during Excavation. Data to be used todetermine contamination control will be air-monitoring data collected at the dig face; from the breathingzone of the workers, and from inside the weather structure during excavation. Results will consist ofconcentrations of dust/and the rare-earth surrogate and will be used to calculate average airborne

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concentrations. The resulting concentrations will be used to determine effectiveness of CDR grout toreduce contaminant/dust spread to a level to allow bubble-suited entry and possibly to be considered aprimary confinement structure to reduce dust/rare-earth surrogate emission.

Data from smear samples collected from the face of the monolith during excavation will be used todetermine effectiveness of CDR grout as a primary dust control mechanism.

8.5.12 Test on Contamination Migration. Contamination migration will be determined usinganalytical data from solid samples and visual evaluation of the monoliths. Solid samples will be collectedfrom the monolith and sideburden soil to be analyzed for rare-earth tracers using IPC-MS. These datawill be used with the air-monitoring data to determine migration or fate (mass balance) of these materials.

8.5.3.3 Test—Destructive Examination/Monolith Integrity. Data to be used to determinemonolith integrity will be qualitative data from visual inspection of the monolith during excavation and ofsolid samples taken from the exposed monolith. Solid samples from the monolith will be visuallyinspected to evaluate integrity of the grout during excavation.

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9. QUALITY ASSURANCE

This treatability study and its associated activities shall be conducted according to a QualityAssurance Program that meets the requirements of DOE Order 5700.6C, "Quality Assurance," or anational consensus standard such as American Society of Mechanical Engineers procedure NQA-1,"Quality Assurance Requirements for Nuclear Facility Applications." The Quality Program Plan for theINEEL Environmental Restoration Program (LMITCO 1997), can also be used, if desired, along with theQuality Assurance Project Plan for Waste Area Groups 1, 2, 3, 4, 5, 6, 7, and 10 (INEL 1995a). If theoperational vendor for the treatability study desires to use their own Quality Program Plans and QualityAssurance Project Plans, copies of these plans need to be sent to the INEEL for intemal review andapproval prior to initiating testing.

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10. HEALTH AND SAFETY

Pretesting of the in situ grouting technologies will be performed in the laboratory, while thesimulated field testing portions of the in situ grouting treatability study will be performed at the INEELRWMC. A task-specific Health and Safety Plan will be prepared to cover testing activities planned forthe INEEL. The Health and Safety Plan will establish the procedures and requirements to be used tominimize health and safety risks to persons working on the project. It will contain information about thehazards involved with performing the work and the specific actions and equipment to be used to protectpersons working at the site. The Health and Safety Plan will ensure that the authorized safety basis asdetailed in the safety analysis report (under development) is adequately implemented during testing. A11personnel, including DOE, M&O contractor, and subcontractor staff, working within the work controlzones for the treatability study will be required to comply with Health and Safety Plan procedures andrequirements. Activity outside the work control zones must comply with applicable health and safetyprocedures as defined in the applicable facility interface agreement.

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11. RESIDUALS MANAGEMENT

The treatability study is being conducted under CERCLA, and all waste generated in bench andsimulated field testing will be considered CERCLA investigation-derived waste. A variety of dispositionroutes are available for CERCLA investigation-derived waste, and all secondary wastes generated duringtreatment will be managed appropriately. Proper waste management for the in situ grouting treatabilitystudy will be specified in the Waste Minimization/Management Plan for the in situ grouting treatabilitystudy (to be written). This plan will list each waste stream to be generated during the treatability studyincluding waste streams from the treatability study process, wastes generated in sampling and analysis,wastes from equipment maintenance, and equipment and supplies remaining at the end of the treatabilitystudy if these are declared waste.

Every separate waste stream in these broad categories will be evaluated to determine whether thewaste is a RCRA solid waste, RCRA characterization hazardous waste (for RCRA solid wastes), whetherthe waste is a RCRA-listed hazardous waste (for RCRA solid wastes), is subject to RCRA land disposalrestrictions for RCRA characteristic or listed hazardous waste or must be treated to meet RCRA landdisposal restrictions, is subject to Toxic Substances Control Act (TSCA) regulation for PCBs, and whatthe concentrations of radioactive constituents are in the waste. These determinations will meetrequirements of the Waste Cenification Plan for the Environmental Restoration Program (INEL 1996),CERCLA, RCRA, TSCA, and applicable DOE orders. The determination will be subject to review by theLMITCO Environmental, Safety and Health manager, LMITCO Environmental Affairs, and LMITCOproject manager. The general strategy for waste management will be:

• Recycle or reuse materials and equipment wherever possible to decrease waste generation

• Return materials to the area of contamination where this can be accomplished successfully

• Manage the stream as nonhazardous, nonradioactive, non-TSCA regulated solid waste wherepossible

• Manage all other waste streams in cooperation with LMITCO Environmental Affairs and theWaste Reduction Operations Complex.

Specific details associated with residual management of the three phases of the in situ groutingtreatability study are detailed below.

11.1 Bench Testing

Bench testing will include studies of simulated waste containing chlorinated solvents and nitratesalts. These wastes may potentially be subject to regulation as RCRA Characteristic Hazardous Waste.Analytical residues such as acid extracts of samples may also be subject to regulation as RCRAcharacteristic waste. All other waste will be RCRA solid waste not subject to hazardous wasteregulations. No radioactive materials will be used during bench testing to support in situ grouting.

Residues contaminated with chlorinated solvents will be analyzed for toxicity characteristicleaching procedure extractable carbon tetrachloride, TCE, and PCE; and a hazardous waste determinationwill be prepared detailing the disposition route for the material. Wastes contaminated with nitrate saltswill be analyzed to determine if they meet the definition of an oxidizer specified in RCRA, and ahazardous waste determination will be prepared detailing the disposition route. Acidic analytical residueswill be discussed in a hazardous waste determination, which will specify the appropriate disposition route.

11.2 lmplementability and Field Testing

The implementability and field tests will use waste surrogates typical of waste found in actualradioactive buried waste at the INEEL SDA. However, no RCRA toxic, TSCA regulated, or radioactivematerials will be included in the test in order to minimize cleanup costs. Terbium oxide will be used tosimulate the actinide oxides in the waste. None of these compounds is subject to regulation under RCRA,TSCA, or DOE orders. The simulated test will include sodium nitrate and potassium nitrate in order tosimulate nitrate in the waste. The regulatory status of these nitrate salts is discussed in more detail below.Nonhazardous Texaco Regal Oil (R&O 68) or canola oil in "kitty litter or commercial calcium silicateabsorbents will be added to simulate the oil base of the organic sludges. These materials are not regulatedas RCRA hazardous waste, with the possible exception of the nitrate salts (which are regulated oxidizersunder some circumstances as discussed below). All other materials added for the simulated field testingwill be nonhazardous components/materials added to simulated waste typically found in actual buriedwaste at the SDA.

Nitrate salts are oxidizers under 49 CFR 173.151, and waste nitrate salts may be regulated as D001RCRA characteristic hazardous waste. Treatment with in situ grouting, however, is expected to stabilizethe salt, leaving it in a nonregulated form. Since the materials used in simulated field testing will not bewaste until the treatability study is over, the nitrate salts should not be subject to RCRA regulation. Ahazardous waste determination will be prepared for the nitrate-salt/grout combination.

All water within the waste pit will be incorporated into the matrix by the in situ grouting action.The resultant dry inorganic residue will be monitored for subsidence and may be sampled to verify nitratesalts and Texaco Regal Oil.

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12. COMMUNITY RELATIONS

Community relations performed in conjunction with the in situ grouting treatability study aredesigned to ensure community understanding of actions taken during the treatability study and to obtaincommunity input on the treatability study program. Community relations are an integral part ofCERCLA. The INEEL Public Affairs group has prepared a programmatic INEEL Community RelationsPlan (INEL 1995). This plan was issued as a DOE document representing the process established bymutual agreement among DOE-ID, EPA Region 10, and IDHW-Division of Environmental Quality toaddress Environmental Restoration concerns at the INEEL. In addition, community relations forWAG 7-13/14 are discussed in both the WAG 7-13/14 Work Plan (Becker et al. 1996, Section 5.2) andthe Addendum to the Work Plan (DOE 1998, Section 6.2). The Community Relations Plan and detailsfor WAG 7-13/14 will guide the actions taken to ensure appropriate public involvement. Specifically, forthe in situ grouting treatability study, a public fact sheet will be prepared and mailed prior to the tests andone will be prepared and mailed after testing. In addition, WAG 7-13/14 will support news/press releasesand will actively relay plans and results at public meetings.

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13. REPORTS

Open lines of communication are essential to ensure smooth and accurate flow of information to allparties directly or indirectly involved with the project during the course of the treatability study. Weeklyreporting will be performed to ensure timely flow of current and projected progress. A number ofdocuments will be prepared to support performing the tests. A final report will document the results ofthe entire treatability study, including any changes from the work plan or test plan.

13.1 Weekly Reports

The technical lead or principal investigator is responsible for submitting weekly reports updatingthe progress of the treatability study. As a minimum, the weekly reports will be distributed to the projectmanager. The project manager, as appropriate, will then forward the weekly reports or relevantinformation to the program manager, DOE-ID project manager, and control account managers. Theweekly reports should include, but not be limited to:

1. Accomplishments of work performed for the week.

2. Anticipated work to be performed for the following week.

3. Any problems or issues encountered and actions taken. This section will include anyvariances from the planned spending profile and any variances in the planned scheduletogether with a plan to address these variances.

13.2 Interim Support Documents

There are a number of anticipated reports that will support the tests. These include a Health andSafety Plan, Quality Assurance Project Plan, Waste Management/Minimization Plan, which shall include(including a Generator Treatment Plan), and In Situ Grouting Treatability Test Plan (including aSampling and Analysis Plan).

In addition, an interim letter report will be provided after the bench testing phase of the in situgrouting treatability study. The report will summarize results of each phase of testing or analysis andprovide necessary information to implement the simulated field testing phase of the in situ groutingtreatability study. As a minimum, the letter report on bench testing will include information on criticalobjectives of the bench testing. The report also should include a discussion of noncritical objectivesplanned for testing, noncritical objectives that were actually tested, and the results of testing.

13.3 Final Treatability Study Report

A treatability study report will be prepared at the completion of the treatability study activities,documenting project activities, results, conclusions, and recommendations. The report will be prepared inaccordance with the EPA's Guide for Conducting Treatability Studies under the ComprehensiveEnvironmental Response, Compensation, and Liability Act (EPA 1988). Complete and accurate reportingare essential because decisions about the in situ grouting technology as a remedial altemative for otherwaste storage areas in the SDA will be based on the outcome of this treatability study.

The final report needs to provide information concerning all data gaps identified during scoping ofthe in situ grouting treatability study. These data gaps have been used in setting critical objectives of the

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treatability study. The in situ grouting report also will contain information on noncritical objectives to theextent that these objectives can be addressed within established budget and time constraints.

The final report will include information on the durability of the monolith produced duringsimulated field testing and data on the economics of the in situ grouting process as applied to buriedmixed wastes.

The final report will include an applicability analysis section estimating cost and implementabilityfor using in situ grouting to stabilize an acre-size site at the SDA. The applicability analysis will estimatethe amount and type of secondary waste generated by such a process (including recycling estimates andinformation on disposal), time estimates for in situ grouting processing, full-operational cost of treatingsuch a site, cost of mobilization and demobilization, data on estimated down times between groutingcampaigns, and frequency estimates and anticipated duration of routine operational breakdowns. Inaddition, the applicability analysis needs to provide information on major equipment purchases thatwould have to be dedicated to the in situ grouting remediation at the SDA. The estimates will be basedon a combination of data from the in situ grouting treatability study and applicable vendor data from otherin situ grouting operations.

Upon submittal of the final report, the subcontractor shall submit a complete data package of thetreatability study to the INEEL for record storage. This shall include a copy of all logbook entries duringthe test, instrumentation monitoring records, files, operational data files, and sampling and analysis files.The subcontractor will retain the originals of these data. The complete data package will include onlythose aspects of the test that have been funded by DOE/INEEL. Additional data may be provided to theINEEL and/or DOE at the subcontractor's discretion. The sampling and analysis data shall be submittedas an Excel computer file for eventual incorporation into the INEEL' s SMO database.

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14. SCHEDULE

The work associated with the in situ grouting treatability study will proceed in accordance with theschedule summary illustrated in Table 14-1. The table reflects the working schedule and there are noenforceable milestones.

The schedule was developed using the INEEL' s Integrated Safety Management philosophy. Thisphilosophy implements a 5-step approach to systematically integrate safety considerations intomanagement and work practices at all levels to accomplish the project mission while protecting thepublic, worker, and environment. The 5 steps include:

• Define the scope of work

• Identify the hazards

• Mitigate the hazards

• Perform work within their controls

• Provide lessons learned, feedback, and continuous improvement.

The Treatability Study Work Plan and Test Plan define the work scope and obtain consensusamong DOE, EPA Region 10, and IDHW. A hazard assessment of the work will be conducted to supportdevelopment of the project Health and Safety Plan. Technical procedures will be developed to guideoperations and identify and mitigate potential hazards. Once the hazard assessment is approved usingINEEL review protocols, the Health and Safety Plan will be reviewed to ensure that the prescribed safetycontrols are being implemented. Combined, these efforts will comprise the authorization basis forperformance of the field testing. Additionally, laboratory and implementation tests provide opportunity toensure lessons learned are incorporated into the planning prior to startup of the field simulated waste testsat Cold Test Pit South.

The evaluation of the data from the treatability study must support the OU 7-13/14 feasibilitystudy. The draft feasibility study is scheduled for completion July 2001. Evaluation of the monoliths andassociated samples from the treatability study testing will be available for drafting of the Proposed Planand Record of Decision.

Table 14-1. Working schedule for the in situ grouting treatability study.

Operable Unit 7-13/14 In Situ Grouting

In situ grouting work plan finalized and approved

In situ grouting bench test plan finalized and approved

In situ grouting field test plan finalized and approved

Commence bench tests

Draft interim report—bench testing

Commence field tests

Complete field evaluation and associated sampling and analysis

Draft treatability study report sent to EPA/IDHW for review and comment

Final treatability study report

9-June 1999

30-June 1999

8-October 1999

12-July 1999

25-October 1999

27-April 2000

22-December 2000

2-April 2001

16-July 2001

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15. MANAGEMENT AND STAFFING

The organization structure reflects the resources and expertise required to perform the in situgrouting treatability study and produce a highly durable waste form, while minimizing the risks to workerhealth and safety. A drilling contractor and grout product subcontractor will be identified for thetreatability study and will be directly responsible for implementation of the technology and for reportingoperational results to the INEEL M&O contractor. However, the INEEL M&O contractor has ultimateresponsibility for technical quality of the work performed. Conducting the in situ grouting treatabilitystudy will be a cooperative effort between these subcontractors and several INEEL M&O Contractororganizations including Environmental Restoration, Applied Engineering Developmental Laboratory, andRWMC operations. In light of the cooperative effort, a team has been assembled to include persons thathave experience with similar treatability study activities and have interfaced with, or directly supported,the RWMC. Key project personnel are listed below:

Agency Team Members Current Personnel

DOE WAG-7 ManagerDOE WAG-7 Project ScientistEPA Region 10IDHW

INEEL M&O Contractor Team Members

ER Buried Waste Department ManagerWAG-7 Treatability Study Project ManagerWAG-7 Treatability Study Technical LeadWAG-7 Remedial Investigation Technical LeadWAG-7 Treatability Study Work Package ManagerWAG-7 Health and Safety Oversight OfficerWAG-7 Feasibility Study Project Manager

In Situ Grouting Principal InvestigatorIn Situ Grouting Field Team LeadIn Situ Grouting Quality Engineer

RWMC Operations SupervisorRWMC Work Control Manager

Subcontractor Team Members

Project Team LeaderContracting Support hiterfaceChief Contracting Officer

A. T. JinesA. T. ArmstrongR. W. PoetenG. Winter

D. K. JorgensenD. F. NickelsonB. BonnemaB. H. BeckerJ. J. JessmoreR. W. RobleeR. A. Hyde

G. G. LoomisE. B. ThompsonR. G. Thompson

J. R. BishoffJ. M. Wasylow

To be determinedTo be determinedTo be determined

The specific responsibilities associated with each of these team members will be defined in boththe Health and Safety Plan and the treatability study test plan. The organizational relationship betweenthese key personnel is detailed in the Interface Agreement between ER and the RWMC (IAG-15).

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16. BUDGET

Table 16-1 shows the proposed budget for the in situ grouting treatability study.

Table 16-1. Proposed budget for the in situ grouting treatability study.

Fiscal Year Proposed Budget

1999 $1.2M

2000 $0.972M

2001 $0.565M

Total $2.737M

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17. REFERENCES

10 CFR Part 835, Code of Federal Regulations, Title 10, Occupational Radiation Protection, Part 835,Subpart K, Design and Control, Paragraphs 1002.c and 1001.a.

10 CFR Part 264.31, Code of Federal Regulations, Title 10, Occupational Radiation Protection,Part 264.31, Design and Operation of Facility.

42 USC § 6901 et seq., 1976, Resource Conservation and Recovery Act, Solid Waste Disposal Act, UnitedStates Code, October 21.

42 USC § 9601 et seq., 1980, Comprehensive Environmental Response, Compensation and Liability Actof 1980 (CERCLA/Superfund), United States Code, December 11.

AEC, 1970, Policy Statement Regarding Solid Waste Burial, Immediate Action Directive No. 0511-21,March 20, U.S. Atomic Energy Commission.

Alcorn, W. S. R., W. E. Coons, and M. A. Gardner, 1990, Estimation of Longevity of Portland CementUsing Chemical Modeling Techniques, Mat. Res. Soc. Symp. Proc., Vol. 176, Material ResearchSociety.

API, 1965, Recommended Practice Standard Procedure for Testing Drilling Fluids, Procedure RP-13B-1,American Petroleum Institute.

ASTM, 1997, Standard Practice for Measurement of Heat of Combustion, Method D-240/D-3286,American Society for Testing and Materials, West Conshohocken, Pennsylvania.

ASTM, 1997, Standard Practice for Oxidation-Reduction Potential of Water, Method D-1498-76,American Society for Testing and Materials, West Conshohocken, Pennsylvania.

ASTM, 1997, Standard Test Method for Accelerated Leach Test for Diffusive Releases from SolidifiedWaste and a Computer Program to Model Diffusive, Fractional Leaching from CylindricalConcrete Waste Forms, Method C-1308-95, American Society for Testing and Materials, WestConshohocken, Pennsylvania.

ASTM, 1997, Standard Test Method for Capillary-Moisture Relationships for Fine-Textured Soils byPressure-Membrane Apparatus, Method D-3152-72 (Reapproved 1977), American Society forTesting and Materials, West Conshohocken, Pennsylvania.

ASTM, 1997, Standard Test Method for Change in Height at Early Ages of Cylindrical Specimens fromCementitious Mixtures, Method C-827-87, American Society for Testing and Materials, WestConshohocken, Pennsylvania.

ASTM, 1997, Standard Test Method for Compressive Properties of Rigid Plastic, Method D-695-91,American Society for Testing and Materials, West Conshohocken, Pennsylvania.

ASTM, 1997, Standard Test Method for Compressive Strength of Cylindrical Concrete Specimens,Method C-39-96, American Society for Testing and Materials, West Conshohocken, Pennsylvania.

ASTM, 1997, Standard Test Method for Density of Bentonitic Slurries, Method D4380-84 (Reapproved1993), American Society for Testing and Materials, West Conshohocken, Pennsylvania.

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ASTM, 1997, Standard Test Method for Specific Gravity, Absorption, and Voids in Hardened Concrete,Method C-643-90, American Society for Testing and Materials, West Conshohocken,Pennsylvania.

ASTM, 1997, Standard Test Method for Splitting Tensile Strength of Cylindrical Concrete Specimens,Method C-496-90, American Society for Testing and Materials, West Conshohocken,Pennsylvania.

ASTM, 1997, Standard Test Methods for pH and Water, Method D-1293-84, American Society forTesting and Materials, West Conshohocken, Pennsylvania.

Becker, B. H., J. D. Burgess, K. J. Holdren, D. K. Jorgensen, S. O. Magnuson, and A. J. Sondrup, 1998,Interim Risk Assessment and Contaminant Screening for the Waste Area Group-7 RemedialInvestigation, DOE/ID-10569, Draft Rev. 1, August, Lockheed Martin Idaho TechnologiesCompany.

Becker, B. H., T. A. Bensen, C. S. Blackmore, D. E. Burns, B. N. Burton, N. L. Hampton, R. M. Huntley,R. W. Jones, D. K. Jorgensen, S. O. Magnuson, C. Shapiro, and R. L. VanHom, 1996, Work Planfor Operable Unit 7-13/14 Waste Area Group-7 Comprehensive Remedial Investigation/FeasibilityStudy, INEL-95/0343, Rev. 0, May, Lockheed Martin Idaho Technologies Company.

Bostick, W. D., P. J. Jarabek, W. A. Slover, J. N. Fieder, J. Farrell, and R. Helferich, 1996, Zero-ValentIron and Metal Oxides for the Removal of Soluble Regulated Metals in Contaminated Groundwaterat a DOE Site, KiTS0-35P, Oak Ridge K-25 Site, 64 pp.

Caldwell, T. B., 1997, Tank Closure Reducing Grout, WSRC-TR-97-0102, 200 pp., WestinghouseSavannah River Company, Aiken, South Carolina.

Daniel, D. E., 1989, "In Situ Hydraulic Conductivity Tests for Compacted Clay," Journal of GeotechnicalEngineering, VoL 115, No. 9, pp. 1205-1225.

DOE-ID, 1979, Environmental and Other Evaluations of Alternatives for Long-Term Management ofStored INEL Transuranic Waste, DOE/ET-0081, December 1979, U.S. Department of Energy-Idaho Operations Office.

DOE-ID, 1989, General Design Criteria, DOE Order 6430.1A, Idaho National Engineering Laboratory,U.S. Department of Energy-Idaho Operations Office.

DOE-ID, 1993, INEL Transuranic Waste Acceptance Criteria, DOE/ID-10074, July 1993, U.S.Department of Energy-Idaho Operations Office.

DOE-ID, 1994, U.S. Department of Energy Radiological Control Manual, DOE/EH-0256T, Rev. 1,April, Idaho National Engineering Laboratory, U.S. Department of Energy-Idaho OperationsOffice.

DOE-ID, 1996, Nuclear Facility Safety, DOE Order 420.1 Chg 2, Idaho National EngineeringLaboratory, U.S. Department of Energy-Idaho Operations Office.

DOE-ID, 1997a, Idaho National Engineering and Environmental Laboratory Reusable Propeny,Recyclable Materials, and Waste Acceptance Criteria, DOE/ID-10381, February, U.S. Departmentof Energy-Idaho Operations Office.

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DOE-ID, 1997b, Quality Assurance Project Plan for Waste Area Groups 1, 2, 3, 4, 5, 6, 7, 10 andInactive Sites, DOE/ID-10587 (formerly INEL-95/0086), Rev. 5, December, U.S. Department ofEnergy-Idaho Operations Office.

DOE-ID, 1998, Addendum to the Work Plan for the Operable Unit 7-13/14 Waste Area Group 7Comprehensive Remedial Investigation/Feasibility Study, DOE/ID-10622, August, Idaho NationalEngineering Laboratory, U.S. Department of Energy-Idaho Operations Office.

EG&G, 1985, A History of the Radioactive Waste Management Complex at the Idaho NationalEngineering Laboratory, WM-Fl -81-003, Rev. 5, July, EG&G Idaho, Inc.

Galloway, K. J., J. J. Jessmore, and A. P. Zdinak, 1997, Test Plan for the Cold Test Demonstration andAcid Pit Stabilization Phases of the In Situ Stabilization Treatability Study at the RadioactiveWaste Management Complex, INEEL/EXT-97/00061, June.

Gerard, B., O. Didry, J. Marchand, D. Breysse, and H. Hornain, 1996, Modeling the Long-TermDurability of Concrete Barriers for Radioactive Waste Disposals, Service Reacteurs Nucleaires etEchangeurs, Departement Mecanique et Technologie des Composants, Clamart Cedex, France,11 pp.

Klute, A., C. Dirksen, 1986, Hydraulic Conductivity and Diffusivity: Laboratory Methods, Chapter 28,Methods of Soil Analyses, American Society of Agronomy, 1188 pp.

Lee, J., Martins, G. P., Weidner, J. R., 1991, Characterization Studies on: (a) Contaminated Batch ofRocky Flats Soil, and (b) Uncontaminated Batch of INEL Soil, EG&G-WTD-9794, 50 pp., EG&GIdaho, Inc., Idaho Falls, Idaho.

LMITCO, 1995a, Data Management Plan for the INEL Environmental Restoration Program, INEL-95/0257, June, Idaho National Engineering Laboratory, Idaho Falls, Idaho.

LMITCO, 1995b, A Comprehensive Inventory of Radiological and Nonradiological Contaminants inWaste Buried in the Subsurface Disposal Area of the INEL RWMC During the Years 1952-1983,INEL-95/0310 (formerly EGG-WM-10903), Rev. 1, August, Lockheed Martin Idaho TechnologiesCompany.

LMITCO, 1995c, A Comprehensive Inventory of Radiological and Nonradiological Contaminants inWaste Buried in the Subsurface Disposal Area of the INEL RWMC During the Years 1984-2003,INEL-95/0135, August, Lockheed Martin Idaho Technologies Company.

LMITCO, 1995d, Environmental Chemistry Laboratory (ECL) Analytical Chemistry Standard OperatingProcedure (SOP), ECL SOPs IM-6.1; IP-1.3.

LMITCO, 1997, Implementing Project Management Plan for the Idaho National Engineering andEnvironmental Laboratory Remediation Program, INEEL/EXT-97-000323.

Loomis, G. G., and D. N. Thompson, 1995a, Innovative Grout/Retrieval Demonstration Final Repon,INEL-95/0001, January, Lockheed Idaho Technologies Company.

Loomis, G. G., D. N. Thompson, and J. H. Heiser, 1995b, Innovative Subsurface Stabilization ofTransuranic Pits and Trenches, INEL-95/0632, December, Lockheed Idaho TechnologiesCompany.

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Loomis, G. G., A. Zdinak, and C. Bishop, 1996, FY-96 Innovative Subsurface Stabilization Project,INEL-96/0439, November, Lockheed Idaho Technologies Company.

Loomis, G. G., A. Zdinak, and J. Jessmore, 1999, Acid Pit Stabilization Project (Vol. 1 & 2),INEEL/EXT-98/00009, March, Lockheed Idaho Technologies Company.

Lowry, William, V. Cipman, K. Kisiel, J. Stochton, 1999, "In Situ Permeability Measurements withDirect Push Techniques," SEASF-TR-98-207, Science and Engineering Associates, Santa Fe, NewMexico, 102 pp.

McQuary, J. et al., 1991, A Summary of the Environmental Restoration Program Retrieval DemonstrationProject at the Idaho National Engineering Laboratory, EGG-WTD-9291, Rev. 1, February.

Merck & Co., 1983, The Merck Index, An Encyclopedia of Chemicals, Drugs, and Biologicals, TenthEdition Merck & Co., Inc., Rahway, New Jersey.

Shoemaker, S. H., J. F. Greiner, and R. W. Gillham, 1995, Permeable Reactive Barriers, Assessment ofBarrier Containment Technologies, eds., R. R. Rumer, J. K. Mitchell, Section 11, pp. 301-353,NTIS #PB96-180583.

Smith, T. H., and D. E. Kudera, 1996, Comparison of the Pit 9 Project Inventory of Contaminants Againstthe Corresponding Ponion of the Historical Data Task Inventory and Recommended RevisedQuantities, INEL-96/0055, Rev. 0, January, Lockheed Idaho Technologies Company.

U.S. Department of Health, Education, and Welfare, 1970, "Radiological Health Handbook," Pb-230846,458 pp., Rockville, Maryland.

U.S. Department of Interior-Bureau of Reclamation, 1977, "Ground Water Manual," Water ResourcesPublication, First Edition, p. 480,

U.S. EPA, 1993, Unconfined Compressive Strength, OSWER Directive No. 9347.00-2A.

U.S. EPA, 1997, Online Database, Regulated Toxic Chemicals,http://mail.odsnet.com/TRIFacts/131.htm1, U.S. Environmental Protection Agency.

U.S. EPA, 1998, Guidance for Conducting Remedial Investigations and Feasibility Studies UnderCERCLA, Interim Final, EPA/540/G-89/004, October, U.S. Environmental Protection Agency.

Weidner, J. R., A. J. Sondrum, T. G. Kaser, and W. C. Downs, 1992, Vapor Pon Permeability,Engineering Design File ER-101, EG&G Idaho, Inc.

Wood, T. R., and G. T. Norell, 1996, Integrated Large-Scale Aquifer Pumping and Infiltration Tests,INEL-96/0256, Idaho National Engineering Laboratory.

WSRC, 1992, Radiological Performance Assessment Z-area Salt Stone Disposal Facility, WSRC-RP-92-1360, Westinghouse Savannah River Company, Aiken, South Carolina.

WSRC, 1994, Radiological Performance Assessment E-area Vaults Disposal Facility, WSRC-RP-94-218, Westinghouse Savannah River Company, Aiken, South Carolina.

Yokuda, E., 1992, Locations of Pits, Trenches, and Soil Vault Rows, Engineering Design File ERPWAG-7 05, Rev. 2, July, EG&G Idaho, Inc.

17-4

Appendix A

Detailed Strategy for Testing the Effectivenessand Durability of the In Situ Grout,

Long-Term Disposal Option

Appendix A

Detailed Strategy for Testing the Effectivenessand Durability of the In Situ Grout,

Long-Term Disposal Option

INTRODUCTION

The objective of this appendix is to further clarify the evaluation strategy for the long-termperformance of in situ grouting as a treatment technology for Subsurface Disposal Area contaminants ofpotential concern. To assess the effectiveness of an in situ technology for long-term disposal (LTD), onemust be concerned with two aspects of performance: (1) the durability of the waste form, or how long itwill last in the given environment, and (2) its effectiveness on inhibiting the migration of contaminantsfrom the treated site. This technology evaluation strategy addresses each aspect of performance throughthe interaction of two primary activities: (a) generation and/or compilation of grout performance data(contaminant-specific solubility modeling, compilation of contaminant-specific diffusion coefficients, andgrout property measurements), and (b) utilization of these data in risk modeling.

Modeling outputs, combined with modified administrative information from the in situ vitrificationtreatability study and past in situ grouting hot testing will be considered during the alternative evaluationstage of the feasibility study. These primary activities will be discussed in greater detail in the followingsections.

To assess grout performance, one must first understand the physical transport mechanismsassociated with the Subsurface Disposal Area (SDA) contaminants of potential concern and how in situgrouting contributes to the immobilization of these components.

Immobilization of Waste Components by Grout

The nature of the SDA waste components varies through a broad spectrum of properties affected bysite-specific geological parameters (reference Section 1.6 of the Work Plan). In reviewing theseinteractions, virtually all of the contaminants are potentially transported via ground water or vapor spacegaseous diffusion. Thus, the primary line of defense for any in situ treatment becomes the control of sitepermeability. Two transport mechanisms can be involved. In one case, the contaminants are transportedby advection, i.e., the movement of the water itself. The second case is transport by contaminant diffusionand is the dominant mechanism when the fluid phase is static. The fluid phase includes aqueous groundwater and soil gas

The properties of the fluids in the treated waste site are affected in several ways by the in situ groutprocess. The permeability of the waste site is decreased because the open space in the waste is filled withlow-permeability grout. Grout decreases both the hydraulic conductivity and air permeability. Thedecrease in air permeability, and therefore gaseous diffusion, is evaluated by the test ofmicroencapsulation. In addition, the treated waste site is mechanically stable and subsidence is prevented.Thus, ponding of water at ground surface is prevented.

In some cases, contaminant diffusion through the intergranular water in the waste matrix can alsobe affected by the chemical properties of the grout. The rate of diffusion of a particular contaminant is afunction of the diffusion coefficient and concentration of the contaminant. The diffusion coefficient of

A-1

most contaminant ions can be changed litðe by the available choices among cementitious grouts.However, the concentration, and, therefore, the rate of diffusion, of many contaminants in aqueoussolution is affected by the oxidation-reduction potential (Eh) and acid-base properties (pH) of theintergranular water surrounding the waste material. Eh and pH are, within limits, a function of groutcomposition. A grout can be chosen that provides a particular Eh and pH environment and that controlsthe solubility of a particular contaminant. Inappropriate environments (and grouts) can be avoided. TheSDA contaminants of potential concern, which are affected by pH and Eh of the grout, include U, Np, Pu,Am, and Tc. Indirectly, C14, Cs, Sr, and other materials are all affected. In general, volatile organiccompounds (VOCs) are not significantly affected by grout chemical properties.

GROUT PERFORMANCE DATA

The generation of grout performance data is discussed in great detail in this work plan. Insummary, data are to be collected from three test phases: bench, implementability, and field testing. Onlyminor qualitative information associated with grout performance will be collected from implementabilitytesting. Thus, no further discussion of this phase will be presented in this appendix. It is important to notethat each phase of testing, while having its own overall objective (i.e., Bench Testing: grout selection; andField Testing: full-scale operational assessment), has been designed to generate specific information tosupport the evaluation of product durability and effectiveness. Additionally, testing has been designedsuch that select data from these phases also act as quality control checks of like data from other sets ofmeasurements. For example, the results of laboratory hydraulic conductivity measurements must beconsistent with the results of field hydraulic conductivity measurements. Lack of consistency indicatesthat some factor is not being taken into account.

As discussed in Section 1 of the work plan, specific analytical data will be utilized as direct inputsto the Idaho National Engineering and Environmental Laboratory (INEEL) WAG-7 risk model forprocessing LTD effectiveness information. Risk-model iterations will also receive empirical data fromtreatability study efforts relative to contaminant solubility chemistry and diffusivity to enhanceprocessing. The following list of model inputs generated by treatability study efforts will be consideredalong with currently utilized standards for estimating risk to the aquifer, i.e., surface water infiltrationrate, basalt hydraulic conductivity, depth to aquifer, etc.

• Monolith life expectancy (how long it will provide hydrologic control and chemical bufferingeffects to the treated subsurface environment)

• Thrust block life expectancy (how long it will provide hydrologic control to the extendedsurface region)

• Representative hydraulic conductivity and porosity for the life of the monolith

• Representative hydraulic conductivity and porosity for the life of the thrust block

• Quantified effects of anticipated fracturing on hydraulic conductivity for both the thrust blockand monolith

• Monolith unsaturated flow

• Release mechanism (diffusion or dissolution) and associated rate for each contaminant ofconcern identified in the work plan

• Effects of microencapsulation on VOC migration.

A-2

Utilization of these data in processing-model runs eliminates conjecture and gives consideration tocertain environmental variables not previously addressed by the model, thus increasing output precision.

Test and Empirical Data Generation

Table 1 reflects those data types that will be collected from bench and field testing that willcontribute to the assessment of long-term grout performance. These measurements will either be utilizedas independent input variables or to derive empirical variables for the modeling effort. Subsequentdiscussions of each data type follow.

Table A-1. Bench- and field-testing requirements for long-term disposal assessment.PerformanceRequirement

Data Type BenchTesting

FieldTesting

Test Method

Hydraulic properties Hydraulic conductivity X X ASTM-D-5084-90

Porosity X X ASTM C-642-90

Shrinkage X ASTM C-827-87

Tensile strength X X ASTM C-496-90

Unsaturated flow X ASTM D-3152-72

Chemical buffering Oxidation-reductionpotential

X X ASTM D-1498-76

Hydrogen-ion activity X X ASTM D-1293-84

Grout dissolution Accelerated leach test X X ASTM C-1308-95

Effects of grout on VOC concentration in X SW-846encapsulation on stabilized samples Method 8260VOC release

Hydraulic Properties

Hydraulic Conductivity—Hydraulic conductivity is important in determining migration of surfacewater through the thrust block or monolith structures. Measurements of hydraulic conductivity performedon neat and matrix-loaded samples (reference Section 4.1.1) in the bench test will be compared with thoseperformed on biased monolith samples collected in the field. Because the thrust block will be comprisedof nearly 100% neat grout, such laboratory data will be considered representative of the thrust blockmaterial. Measured hydraulic conductivities from monolith samples will then be compared with afield-measured value(s) designed to be representative of the entire treated monolith region. Assuming acorrelation is observed, the field measurement will be utilized directly by the model. The samplehydraulic conductivity measurements provide quality assurance information about the field hydraulicconductivity measurements. If the two sets of data are consistent with one another, then the fieldmeasurements will be utilized directly by the model. If the data are not consistent with one another, bothsets of data will be reexamined to determine the reason for the inconsistency. A determination will bemade at that point regarding the suitability of either data set for use in the model. It should be mentionedthat this one variable is the most sensitive model input for determining long-term monolith performance.

A-3

Porosity—The porosity is a measure of the interstitial space and is expressed quantitatively as therelationship between the volumes in the grout material occupied by solids and nonsolids. As withhydraulic conductivity, porosity measurements of bench test versus biased field samples will beconducted. Representative porosity measurements will be directly utilized as performance modelinginputs.

Shrinkage—Shrinkage is an important variable for empirically estimating the potential extent offracture development from the curing process. Shrinkage cracks may occur as a result of excess water inthe grout, variations in the grout composition, or temperature rise during grout curing. Shrinkage will bemeasured in bench tests on neat grout samples according to ASTM C-827-87, "Standard Test Method forChange in Height at Early Ages of Cylindrical Specimens from Cementitious Mixtures." This testprovides information on volume changes taking place in cementitious mixtures between the time just aftermixing and the time of hardening. An estimated net fracture volume will be derived from shrinkagemeasurements. Following cure and excavation, a fracture assessment will be performed of the monolith inthe field, particularly noting thermal-mechanical stresses such as (a) degree of fracture penetration intothe monolith, (b) fracture zoning and orientations, and (c) fracture spacing and aperture dimensions.Assessment of the fracture networks will be compared with bench data and used to qualitatively predicttheir effects on the monolith's permeability for modeling purposes.

Tensile Strength—Tensile strength is a measurement of a material's ability to withstand loadsapplied in tension and indicates resistance of the stabilized waste to cracking due to shrinkage orsettlement of underlying fill. Tensile strength (splitting strength) will be measured on laboratory (neat andmatrix-loaded samples) and biased field samples. Such measurements will contribute to an empiricalestimation of fracture aperture (along with shrinkage measurements) in the monolithic structure fromcuring and grout interactions with waste matrices and debris. As with estimations from shrinkage,assessment of fracture networks in the field will be compared with these data for use as a qualitativeprediction of their effects on the monolith's permeability for modeling purposes.

Unsaturated Flow—Moyement of water in the unsaturated zone is of considerable interest fordetermining quantity of water flux and water content of the resultant soilcrete. Unsaturated flowdeterminations will be measured following ASTM D-3152-72 (Reapproved 1977), "Standard TestMethod for Capillary-Moisture Relationships for Fine-Textured Soils by Pressure-Membrane Apparatus."This test method covers the determination of capillary-moisture properties of fine-textured materials asindicated by the moisture content-moisture tension relationship determined by pressure-membraneapparatus using tensions between 1 and 15 atmospheres. Moisture tension (matrix suction) is defined asthe equivalent negative gage pressure, or suction, in soil moisture. Moisture content is a measure of thewater retained in the soil or, in this application, the monolith material. Such measurements will beperformed on biased field samples only with a representative value to be utilized for modeling purposes.

Chemical Buffering Properties

Oxidation-Reduction Potential (Eh ) and Hydrogen-Ion Activity (pH)—Leachability of hazardousconstituents (e.g., metals) may be governed by the buffered pH and Eh of emplaced grout. Measurementswill be performed on both bench neat grout samples and biased field samples. Thermochemicalcomputations involving these properties will be important in determining if the desired chemical effectsare present to chemically buffer the target contaminants. As part of the bench tests, a subcontract will beissued to develop two deliverables for direct utilization in the risk model. The first: a literature review ofradionuclide solubility studies for identification of a consistent set of thermodynamic data forradionuclides (solid and aqueous phases); and the second, a literature search to provide aqueous diffusioncoefficient data for carbon tetrachloride, Pu, Am, Np, U, Tc, I, Sr, C, and Cs in a grout-like substance.

A-4

Thermochemical Computations (Contaminant Solubilities and Diffusion Coefficients)—Asdiscussed, grout formulations can be manipulated to enhance the chemical properties of the monolith toprovide the optimal environment for immobilization of contaminants. Materials such as blast furnace slaghave been used to create a reducing environment to immobilize radionuclides such as Tc that can behighly mobile under oxidizing conditions. As part of the bench work, a subcontracted modeling effort willaid in the selection of a grout composition that will limit the solubility of problematic radionuclideswithout enhancing the mobility of other contaminants. The main purpose in this evaluation is todetermine the solubility limit of the key contaminants identified in this work plan for each grout underconsideration. The contaminants include Pu, Am, Np, U, Tc, I, Sr, C, and Cs. Solubility of eachcontaminant will be computed as a function of representative grout-buffered Ehs and pHs. The Eh rangeis from —600 to 200 mv. The pH range is from 8 to 13. This modeling effort will be documented and theresults provided in the interim report.

As a separate task, the subcontractor will carry out a literature search and provide aqueousdiffusion coefficient data for carbon tetrachloride, nitrate, Pu, Am, Np, U, Tc, I, Sr, C, and Cs in agrout-like substance with previously described Eh and pH ranges. The strontium and nitrate data from theliterature will be used as standards to compare with similar measurements made in this treatability study.If the data are comparable, then the grout materials are also comparable and literature values for othercontaminant species can be used for the grouts tested in this study.

Results from this effort will allow for the computation of potential concentrations of contaminantsin the aqueous phase given grout-specific buffering capacities and an associated diffusion potential. Theseresults will be used to aid in grout selection and as a direct input to the risk-modeling effort for evaluationof LTD performance of the field-deployed grout relative to SDA contaminants of potential concern.

Grout Dissolution/Degradation Properties

Accelerated Leach Test—The accelerated leach test is a critical test that will provide informationrelat ve to chemical stability and diffusion information for grout components in the SDA environment.Test results will be used to estimate the dissolution rate of the grouted waste form. This information willindicate the length of time the grout will perform. Except for WaxFix, each grout sample will be tested tomeasure the release of calcium, silicon, and aluminum from the grout matrix. These elements are commoncomponents of cementitious grouts and represent a range of solubilities. Samples will be tested accordingto ASTM C-1308-95. An inductively coupled plasma spectrophotometer will then be used to determineconcentrations of calcium, silicon, and aluminum in the leachate. Results of these analyses will beevaluated using the Accelerated Leach Test computer program that will calculate the incremental fractionleached, cumulative fraction leached, diffusion coefficient that best fits the leaching data, and value thatdescribes the goodness-of-fit between the data- and diffusion-model results.

Analysis of the leachate for strontium and a nitrate tracer will provide conservative diffusioncoefficients to standardize results from the previously described literature search for each grout relative toSDA contaminants of potential concern.

Durability of Paraffin-Based Grout—Expected durability of paraffin-based grouts will beevaluated in an Engineering Design File based on published results from previous studies. The primaryfactors influencing the durability of paraffin in the environment over time are biological degradation,including available moisture, nitrate, phosphate, and potassium in the waste form; composition of theparaffin (especially branching frequency and configuration); thickness of the paraffin coating;concentration and availability of oxygen, nitrate, sulfate, and other oxidizing agents; and presence andconcentrations of compounds that inhibit bacterial growth (other hydrocarbons and toxic metals). Resultsof the study will be included in the treatability study interim report. Data will be used in the grout

A-5

selection process for long-term durability. The report will present expected durability of paraffin-basedgrout in the SDA, effects of the various identified factors on the expected rate, and uncertainties inestablishing the rate. Sources for studies of degradation rates for paraffin degradation include laboratorystudies of hydrocarbon degradation, controlled full-scale experiments, and uncontrolled full-scaleexperiments.

Microbial-Induced Degradation of Grout—The effect of microbial-induced degradation of theselected grout material will be evaluated in an Engineering Design File based on published results fromprevious studies. Variables to be considered will include grout composition, moisture, hydraulicconductivity, ground water composition (including Eh and pH), temperature, and available nutrients. Theanalysis will provide an estimated rate of degradation of the selected grout material in the SDAenvironment.

Effects of Grout on Encapsulation of VOCs

VOC Microencapsulation—Bench-scale tests of VOCs remaining in grout-stabilized simulatedorganic sludge will provide information on the effectiveness of microencapsulation in decreasing therelease rate of VOCs from the SDA. This test will determine the relative effectiveness of grouts, at theiroptimum viscosity, in stabilizing VOCs. Samples of simulated organic sludge stabilized with grout willbe analyzed for VOC content according to EPA SW-846 Technique 8260. A gas chromatograph-massspectroscopy will be used to determine VOC levels following extraction from the sample using purge andtrap techniques. Results of the test will be evaluated by comparing the amount of each constituentretained in the grouts with the amount retained by baseline samples of untreated sludge. These data willnot be considered in the grout selection process.

RISK MODELING

Phased Approach

The first step of the systematic modeling effort would be to determine if the LTD technologyreduces risk to an acceptable level. If it does not, then the technology does not need to be consideredfurther. If the technology performance at the present time is acceptable, than changes in the properties ofthe system as it degrades with time can be evaluated. The analysis would be carried out in a phasedapproach. The first phase would determine order-of-magnitude effects to establish points of potentialconcern. Subsequent phases, if necessary, will use more precise estimates to obtain the levels of precisionnecessary to malce a decision, i.e., is the performance acceptable for the desired period: 1,000 to 10,000years or more.

As previously discussed, the LTD buried waste stabilization system is made up of two physicalcomponents: a thrust block and a monolith of grout encapsulating buried waste. In addition, thecomposition of the thrust block and monolith is a third variable, which may also affect the properties ofthe system. The thrust block will be buried beneath a landscaped soil cover or integrated into anengineered cap. Beneath the thrust block is the monolith of grout, which encapsulates and fills the voidsin the buried waste. The grout material may or may not change the chemical properties of the groundwater or contaminants. Each component of the system and their interactions will be analyzed.

The long-term performance of the treated waste site will be determined by estimating the risk as afunction of rate of monolith degradation and also contaminant diffusion out of the monolith. It would beassumed that the SDA climate and ground water composition would remain unchanged, and that thetreated waste would be below the frost line. The rate of chemical degradation/dissolution of the monolithwill be estimated from the measured grout solubility data, field observations of the monolith's physical

A-6

properties and heterogeneity, and composition of the SDA ground water. The rate of contaminantdiffusion would be estimated by measurement and from data reported in the literature. The object of thisexercise is to supply a set of time-dependent values to the risk model so that the risk to human health andthe environment can be estimated as a function of time. If the properties of the grout were adequate, thenthe grout would be accepted as a viable candidate for the Remedial Investigation/Feasibility Study. If theproperties were inadequate, then the assumptions would be examined to determine if the model isreasonable. If the LTD technology is still unacceptable, then it can be dismissed from furtherconsideration.

QUALITY ASSURANCE

The treatability study will provide quantitative data and accepted nuclear industry information tothe INEEL-developed risk model for evaluation of in situ grouting's long-term performance. A significantvolume of qualitative data, primarily observations from the monolith excavation, will be addressed in thefinal report along with the modeling outputs. Data quality provided for the modeling effort will beensured through the following measures. A11 analytical tests will utilize standard procedures and includemethod-recommended quality control measures. These data will undergo data validation through theINEEL sample management office. Information utilized from nuclear industry literature will be selectedbased on the quality of the information, i.e., thermochemical data and diffusion data will be preassessedfor internal consistency. All modeling assumptions will be based on several pieces of information. Nosingle estimate will be based on a single piece of information, i.e., average monolith hydraulicconductivity values will be based on supporting data from field grab samples, bench samples, fieldmeasured values, and excavation observations. Thus, variables provided to the model for risk assessmentwill provide for a realistic assessment of in situ grouted waste in the SDA environment.

CONCLUSIONS AND SUMMARY

The long-term disposal option of the in situ grouting technology is designed to be applied in situ tothe transuranic pits and trenches at the SDA. Successful application of the technology would provide athree-tiered strategy of waste immobilization. The in situ grout would (1) provide physical stability to thewaste site, (2) reduce the hydraulic conductivity of the waste site, and (3) provide a beneficial chemicalenvironment for the chemical immobilization of waste components.

The strategy of the LTD treatability study can be described by three interrelated test activities,namely, the bench test, intermediate test, and field test. The bench test will provide data for groutselection, long-term durability estimates, and contaminate-release-rate prediction. It will also provide astandard of comparison for field samples and measurements. The intermediate test is a set of field testswith the specific objective of determining equipment settings necessary to apply the potential grouts toburied waste at the SDA. The field tests are a set of measurements carried out at full scale to estimate(1) application idiosyncrasies, parameters, and variables; (2) grout mechanical performance, i.e., voidfilling, cracking, mixing with soil and waste, set times, etc.; (3) treated site hydraulic conductivity and itsvariability, and (4) chemical properties of grout and treated waste. One aspect of the test strategy is thatmuch of the bench testing will serve as a standard of comparison for field testing. This is done becauselaboratory tests are carried out under carefully controlled conditions, far greater control than is possiblefor field tests. This strategy provides a standard of comparison for the interpretation of complex anddifficult-to-interpret field data.

Data obtained from the test program will be provided to the SDA risk-assessment program so thatthe reduction in risk from applying LTD technology can be evaluated.

A-7

Appendix B

In Situ Grouting Target Inventory

Appendix B

In Situ Grouting Target Inventory

The target inventory for the proposed in situ grouting treatability study was evaluated fully as partof the treatability study planning. The evaluation focused on the ability of in situ grouting to remediatecontaminants and waste types buried routinely at the SDA. The evaluation was intended to help identifyin situ grouting performance against the contaminants of potential concern in Table A-1 and determinewhether in situ grouting would have problems with certain types of waste packages. The detailed in situgrouting target inventory evaluation is shown in Table A-1 of Appendix B of the OU 7 13/14 RI/FS WorkPlan Addendum and summarized in the following tables: Table 1 for long-term stabilization andTable A-2 for confinement during retrieval. Table A-1 and Table A-2 list the expected fate of the primarycontaminants of potential concern, identifies nontarget contaminants and waste types that may potentiallypresent technical problems for in situ grouting, the expected fate of the contaminant or waste type, and adetermination of whether the contaminant or waste type may affect implementation.

Table B-1. Evaluation of SDA contaminant fate following in situ grouting for long-term management.

Contaminant Contaminant Fate Concern

Ac-227 Immobilized by high pH; low permeability limits movement insolution; anion complexes attracted to positively chargedphases in grout.

Ag-108M Immobilized by high pH; low permeability limits movement insolution; anion complexes attracted to positively chargedphases in grout.

Am-241 Immobilized by high pH; low permeability limits movement insolution; anion complexes attracted to positively chargedphases in grout.

C-14 It may equilibrate with carbonate in grout and soil, or CO2dissolved in ground water. Low permeability may limittransport.

Decreased permeability may limit leaching and transport.

Remains in irradiated metal.

CI-36

Co-60

Cr-51

Cs-137

Eu-154

H-3

1-129

Kr-85

Mn-53

Nb-94

Ni-59 and Ni-63


Fixed in illitic clays present in waste site soil.

Immobilized by high pH; low permeability limits movement insolution; anion complexes attracted to positively chargedphases in grout.

Exchanges with water moving through the grouted waste.

Decreased permeability may limit leaching to solution.

Low permeability may decrease rate of release.

Remains in inadiated metal.

Remains in inadiated metal.


Organic ligandsare not destroyed



Probably none

Probably none

Probably none

Probably none

Probably none


None

Probably none

Probably none

Probably none

Probably none

Probably none.

B-1

Table B-1. (continued).


Np-237 Immobilized by high pH; low permeability limits movement insolution; anion complexes attracted to positively chargedphases in grout.

Pa-231 Immobilized by high pH; low permeability limits movement insolution; anion complexes attracted to positively chargedphases in grout.

Pb-210 Potential to stay in metal. Immobilized at higher pH. Smallgamma emission (46 kEV) means there is little dose concem.

Pu-239 and Pu-240 Immobilized by high pH; low permeability limits movement insolution; anion complexes attracted to positively chargedphases in grout.

Ra-226 Lower gas phase permeability may limit movement out ofwaste.

Sb-124 and Sb-125 Lower permeability may limit movement in solution.

Sr-90 Lower permeability may limit movement in solution.Precipitates with calcium during precipitation of calcite fromSDA ground water.

Tc-99 Stays in irradiated metal. Immobilized by reducing andalkaline environment.

Th-228 Immobilized by high pH; low permeability limits movement insolution; anion complexes are attracted to positively chargedphases in grout.

T1-204 Low permeability limits movement in solution; pure betaemitter, so there is no dose concern.

Immobilized by reducing and alkaline environment; lowpermeability limits movement in solution; anion complexesattracted to positively charged phases in grout.

Lower permeability limits water and free-phase movement.

U-232, -233, -234,

-235, -236, and -238

Acetone

Alcohols

Aluminum nitratenonhydrate

Antimony

Arsen c

Benzene

Beryllium

Beryllium oxide


Immobilized by high pH; low permeability limits watermovement.

Anion complexes attracted to positively charged phases.

Immobilized by high pH; low permeability limits movement insolution. Anion complexes attracted to positively chargedphases.

May be reduced to more toxic As(III) under reducingconditions. Adsorption decreases above pH 9 for As(III) andabove pH 7 for As(V); lower permeability will limit movementin solution.

Low permeability limits movement in solution, vapor, and freephases.

Monolith limits potential for airborne beryllium.

Monolith limits potential for airborne beryllium.

Organic ligandsnot destroyed


Probably none


None

None

None

Probably none


Probably none


May not beimmobile

May not beimmobile

Nitrate may effectdurability of thegrout

Probably none

May be releasedunder reducingconditions andhigh pH

May not beimmobile

None

None

B-2


Contaminant

1,4-Bis(5-phenyloxazol-

2-YL)benzene

2-B utanone

Butyl alcohol

Cadmium

Carbon tetrachloride

Chloroform

Chromium

Copper

Copper nitrate

Dibutylethylcarbutol

Diisopropylfluoro-

Phosphate

Ether

Ethyl alcohol

Hydrazine

Lead

Mercury nitrateMonohydrate

Methyl alcohol

3-Methylcholanthrene

Contaminant Fate


Lower permeability limits movement in solution, vapor, andfree phases.


Immobilized by high pH. Low permeability limits movementin solution. Anion complexes attracted to positively chargedphases.


Low permeability limits water and free-phase movement.

Stays in metal. Immobilized by reducing environment.


Lower permeability limits movement in solution; high pHlowers Cu(I) and Cu(II) mobility.


Low permeability limits water and free-phase movement.


Readily biodegraded; low permeability lim ts movement insolution, vapor, and free phases.

Readily oxidized by soil sesquioxides, etc.; low permeabilitylimits water, free-phase, and gas-phase movement.



Lower permeability limits water, free-phase, and gas-phasemovement.

Lower permeability limits water, free-phase, and gas-phasemovement.

Concern

May not beimmobile

May not beimmobile

May not beimmobile

May not beimmobile; groutmay decompose;organic ligandsnot destroyed

May not beimmobile

May not beimmobile

Probably none


Nitrate salts mayaffect durability ofgrout

May not beimmobile

May not beimmobile

May not beimmobile

May not beimmobile

May not beimmobile


Organic ligandsnot destroyed;nitrate may affectdurability of thegrout

May not beimmobile

May not beimmobile

B-3


Contaminant

Methyl isobutyl ketone

Methylene chloride

Nickel

Nitric acid

Potassium nitrate

Silver

Terphenyl

Tetrachloroethylene

Toluene

Tributyl phosphate

1,1,1-Trichloroethane

Trichloroethylene

1,1,2-Trichloro-1,2,2-trifluoroethane

Trimethylolpropane-Triester

Uranyl nitrate

Contaminant Fate

Low permeability limits water, free-phase, and gas-phasemovement.

Readily biodegraded; lower permeability limits water, free-phase, and gas-phase movement.

Stays in metal.

Neutralized by soil. Nitrate gradually converted to other formsand reduced in soil.

Nitrate gradually converted to other forms and reduced in soil.

Immobilized by high pH;solution; anion complexesphases in grout.

Lower permeabilityfree phases.



Lower permeability limitsfree phases.




Lower permeability limitsfree phases.

Lower permeabilitymovement.

low permeability limits movement inattracted to positively charged

limits movement in solution, vapor, and



movement in solution, vapor, and




movement in solution, vapor, and

limits water, free-phase, and gas-phase

Concern

May not beimmobile

May not beimmobile

Probably none

Nitrate may affectdurability of thegrout

Nitrate may affectdurability of thegrout


May not beimmobile

May not beimmobile

May not beimmobile

May not beimmobile

May not beimmobile

May not beimmobile

May not beimmobile

May not beimmobile

May not beimmobile

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Table B-2. Evaluation of SDA contaminant fate following in situ grouting for retrieval.


Ac-227

Ag-108M

Am-241

C-I4

C1-36

Co-60

Cr-51

Cs-137

Increased cohesionexcavation. Lowerthrough waste.





Stays in irradiated

limits particulate release duringpermeability limits water movement





metal.

Stays in irradiated metal.


Eu-154 Increased cohesionexcavation. Lowerthrough waste.

H-3 Increased cohesionexcavation. Lowerthrough waste.




1-129 Increased cohesion limits particulate release duringexcavation. Lower permeability limits water movementthrough waste.

Kr-85 Lower permeability may limit gas movement.

Mn-53 Stays in irradiated metal.

Nb-94 Stays in irradiated metal.

Ni-59 and Ni-63 Stays in irradiated metal.

Np-237 Increased cohesion limits particulate release duringexcavation. Lower permeability limits water movementthrough waste.

Pa-231 Increased cohesion limits particulate release duringexcavation. Lower permeability limits water movementthrough waste.

Pb-210 Increased cohesion limits particulate release duringexcavation. Lower permeability limits water movementthrough waste.

None

None

None

C-14 maycontaminateparaffin and otherconstituents

None

Probably none

Probably none

None

None

H-3 maycontaminateparaffin and otherconstituents

None

None

Probably none

Probably none

Probably none

None

None

None

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Pu-239 and Pu-240 Increased cohesion limits particulate release during Paraffin and otherexcavation. Lower permeability limits water movement hydrocarbonsthrough waste. may moderate

neutrons causingpotentialcriticalityconcerns

Ra-226 Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

Sb-124 and Sb-125 Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

Sr-90 Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

Tc-99 Stays in irradiated metal. Probably none

Th-228 Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

T1-204 Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

U-232, -233, -234,

-235, -236, and -238 Increased cohesion limits particulate release during Paraffin and otherexcavation. Lower permeability limits water movement hydrocarbonsthrough waste. may moderate

neutrons causingpotentialcriticalityconcerns

Acetone Miscible in paraffin. May alterproperties of thegrout

Alcohols Miscible in paraffin. May alterproperties of thegrout

Aluminum nitratenonahydrate

Antimony

Arsenic

Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.



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Benzene Miscible in paraffin. May alterproperties of thegrout

Benzine Miscible in paraffin. May alterproperties of thegrout

Beryllium Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

Beryllium oxide Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

1,4-Bis(5-phenyloxazol- Miscible in paraffin. May alter2-YL)benzene properties of the

grout

2-Butanone Miscible in paraffin. May alterproperties of thegrout

Butyl alcohol Miscible in paraffin. May alterproperties of thegrout.

Cadmium Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movement.

Carbon tetrachloride Miscible in paraffin. May alterproperties of thegrout

Chloroform Miscible in paraffin. May alterproperties of thegrout

Chromium Stays in metal. Probably none

Copper Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

Copper nitrate Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

Dibutylethylcarbutol Miscible in paraffin. May alterproperties of thegrout

Diisopropyltluoro-

Phosphate Miscible in paraffin. May alterproperties of thegrout.

Ether Miscible in paraffin. May alterproperties of thegrout

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Contaminant Contaminant Fate Concem

Ethyl alcohol Miscible in paraffin. May alterproperties of thegrout

Hydrazine Powerful reducing agent that can react with sesquioxides and Noneother oxidized materials in soil.

Lead Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

Mercury nitrate Increased cohesion limits particulate release during Nonemonohydrate excavation. Lower permeability limits water movement

through waste.

Methyl alcohol Miscible in paraffin. May alterproperties of thegrout

3-Methylcholanthrene Miscible in paraffin. May alterproperties of thegrout

Methyl isobutyl ketone M scible in paraffin. May alterproperties of thegrout

Methylene chloride Miscible in paraffin. May alterproperties of thegrout

Nickel Stays in metal. Probably none

Nitric acid Neutralized on contact with soil. None

Potassium nitrate Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

Silver Increased cohesion limits particulate release during Noneexcavation. Lower permeability limits water movementthrough waste.

Tetrachloroethylene Miscible in paraffin. May alterproperties of thegrout

Toluene Miscible in paraffin. May alterproperties of thegrout

Tributyl phosphate Miscible in paraffin. May alterproperties of thegrout

1,1,1-Trichloroethane Miscible in paraffin. May alterproperties of thegrout

Trichloroethylene Miscible in paraffin. May alterproperties of thegrout

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Table B-2. (cont nued).

Contaminant

1,1,2-Trichloro-1,2,2-trifluoroethane

Trimethylolpropane-Triester

Uranyl nitrate

Contaminant Fate Concern

Miscible in paraffin. May alterproperties of thegrout

Miscible in paraffin. May alterproperties of thegrout


The target inventory evaluations lay foundations for developing the objectives and test designs forthe in situ grouting treatability study. The evaluations show that in situ grouting for long-termmanagement may be able to treat many of the radiological, hazardous, organic contaminants, and wastetypes buried in the SDA and that in situ grouting for recovery may limit exposure to harmful constituents.Both techniques may be applicable in much of the SDA.

The evaluation, however, identified a number of possible issues with the two technologies: degreeto which actinides and other transition metals are immobilized by grouting; decomposition rate of groutused for long-term stabilization; postgrouting permeability of waste and soil; effects of organic ligands onwaste constituents following stabilization; effects of nitrate on grout durability; mobility of VOCsfollowing grout stabilization; effectiveness of short-term grout in limiting the production of fines duringretrieval; the possible role of paraffin-based grouts in moderating neutrons; and the effects of volatile andsemivolatile organic compounds on the properties of paraffin-based grouts.

These implementation issues were used to develop critical and noncritical objectives of the in situgrouting treatability study (see Section 3).

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Appendix C

Preliminary Criticality Safety ConcernsDuring In Situ Remediation

Appendix C

Preliminary Criticality Safety ConcernsDuring In Situ Remediation

1. PRELIMINARY CRITICALITY SAFETY STUDY FOR IN SITUVITRIFICATION AND IN SITU GROUTING

D. J. Henrikson

1.1 Introduction

Two technologies proposed for treatment of transuranic waste in Waste Area Group (WAG) 7 atthe Radioactive Waste Management Complex (RWMC) are in situ grouting and in situ vitrification. Bothtechnologies immobilize the waste, but use different methods and achieve different results. Since fissileisotopes are present in the waste, a criticality safety program must be implemented for the proposedin situ grouting and in situ vitrification activities. Criticality safety must be addressed for in situ groutingand in situ vitrification so that implementation of either process will not significantly increase thereactivity of the waste, nor cause a criticality accident.

In situ grouting uses a jet-grouting technique to produce a stable monolith of grout-encapsulatedwaste within the buried waste matrix. Grouting material is injected through multiple drill holes within thejet-grouting drill stem and mixes with adjoining soil and waste. The end result is a series of seamless,overlapping columns of grout, forming a large grout monolith. Different types of grouting material areunder consideration for this process, including cementitious materials, mineralogical materials, andpolymeric materials (including paraffin).

In situ vitrification uses electrode heating to melt waste and soil. During the process, volatile andsemivolatile materials are vaporized, while most of the organic and combustible materials in the wasteseam are destroyed by pyrolysis. The molten pool then hardens into a glass and crystalline matrix Mostof the nonvolatile materials are incorporated into the glass and crystalline matrix as oxides; however,some of the nonvolatile metals are reduced and incorporated in the metal layer that is expected to form atthe bottom of the melt (along with the metal debris in the waste seam).

The waste in the SDA is critically safe in its current configuration: This paper examines how insitu grouting and in situ vitrification alter the waste configuration, and how a change in wasteconfiguration affects criticality safety. However, this paper does not assess the long-term stability of thewaste form for continuing immobilization of fissile material. Since this is a preliminary study, upsetconditions that deviate from normal operation are not considered.

1.2 Summary

A preliminary criticality safety study was performed for both in situ grouting and in situvitrification activities, as applied to buried waste at the Idaho National Engineering and EnvironmentalLaboratory (INEEL). The preliminary criticality safety study was performed due to the amount of fissile

c. RWMC Safety Analysis Repon, INEL-94/0226 Rev. 3, LMITCO, June 1998.

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material present in a waste pit. A primary criticality safety concem is the potential for overloaded drums,containing greater than 200 g of fissile material, and the effect of in situ grouting or in situ vitrification onthe reactivity of said drums. In addition, any operation that involves mixing fissile material from multiplewaste packages must be assessed for criticality safety.

In situ grouting was broken up into separate phases of drill string insertion, grout injection, anddrill string withdrawal. Drill string insertion and withdrawal will not affect the criticality safety of thesystem. However, the injection of the grouting material into the buried waste seam can affect thereactivity of the waste seam. The calculated minimum critical mass of plutonium, mixed with groutingmaterial, gives an indication as to whether in situ grouting of an overloaded drum introduces a criticalitysafety concern. Preliminary minimum critical mass calculations demonstrate that a more detailed analysisis needed if polymeric grouting materials, such as paraffin, are used. Although minimum critical massesof plutonium have not yet been determined for cementitious or mineralogical grouting materials (based onresults for soil and glass), it is expected that the resultant masses will be high enough to allow either typeof material to be used safely. So long as an overloaded drum can be grouted safely, so can an entire wastepit.

During in situ vitrification, plutonium and uranium oxides remain in their oxide form, while saltsand metals convert to oxides. Virtually all moderators, including water, organic materials, and graphiteundergo combustion or a combination of volatilization and destruction, leaving the melt area. Preliminarycalculations indicate that a large mass of plutonium, at high concentration, is required for a criticalityduring dissolution into the melt. Once the fissile material is in the melt, it is dispersed by strongconvective currents, tending toward homogeneity as its time in the melt increases. Two criticality safetyissues are unresolved for in situ vitrification. First, the behavior of polyethylene before it is removedfrom the melt needs closer examination. Its fluidity and ability to entrain and move fissile material mustbe analyzed. Second, if significant quantities of beryllium are present in a waste pit, it needs to beevaluated for criticality safety. If these two factors are resolved satisfactorily, the in situ vitrificationprocess can be demonstrated to have no credible criticality scenarios. Work is currently under way toresolve these concerns via additional studies.

Four methods are proposed for in situ vitrification pretreatment. In situ thermal desorption anddynamic compaction have open issues that require further evaluation. In situ disruption and in situstabilization can be performed in a critically safe manner.

1. In situ disniption can be perfonned without impacting the criticality safety of the waste solong as the holes formed by the disruption tool are filled in afterward. If the holes are leftopen, further criticality safety assessment is required.

2. In situ thermal desorption has the same polyethylene concem that was mentioned for in situvitrification. Another concem is that moisture could be reintroduced to the waste area afterdesorption is complete.

3. In situ stabilization is essentially the same as in situ grouting, but would use onlycementitious or mineralogical grouting materials. No criticality safety difficulties areanticipated for these two grouting agents.

4. Dynamic compaction increases the density of the waste without removing moderator. Ittherefore requires further assessment for criticality safety.

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1.3 Discussion

1.3.1 Criticality Safety Background information and Definitions

Transuranic waste at the RWMC contains fissile isotopes. If available in sufficient quantity andconcentration, with the appropriate moderation and reflection, these isotopes can achieve a critical state.The primary fissile isotopes are 239al, 235U, and 233U. Others are 241 pu and 242mAm,three curium isotopesand two californium isotopes.' Only 239P11, 235U, and 233U are present in significant quantities in theRWMC waste.

The term "reactivity" refers to the deviation of a system from a critical value of k = 1, where k isthe neutron multiplication factor for a system. The more reactive a system, the higher its neutronmultiplication. If the neutron multiplication is such that the system is just self-sustaining, it is critical. Asupercritical system has a value of k greater than 1, while a subcritical system has a k value less than 1.Factors that affect the reactivity of a system include reflection, moderation, geometry, and fissile isotopeconcentration. A reflector surrounds the fissile material and reflects neutrons back into the fissile region.Typical reflectors include water, paraffin, beryllium, graphite, concrete, and thick metal. A moderator isintimately mixed with the fissile material. It slows neutrons so that they are more likely to react with thefissile isotopes and cause fission. Hydrogen is the most common effective moderator, particularly in theform of water or polyethylene. Beryllium and graphite are also good moderators, but require largervolumes for criticality.

Each system has an optimally moderated state, where its reactivity is greatest. The geometry of thefissile material affects the system reactivity. As the ratio of volume to surface area increases for a givenvolume, neutron leakage decreases and reactivity increases. The concentration of the fissile isotope isimportant to the system reactivity. If the fissile material is too dilute, criticality cannot be achieved.Related to the uranium concentration is enrichment—the weight fraction of the fissile isotope relative tothe nonfissile isotopes. For example, if uranium has less than 0.7-wt.% 235U, it cannot achieve criticality.'

The minimum critical mass in water for each of the fissile isotopes corresponds to an optimallymoderated and homogeneous mixture of the metal isotope and water, in a spherical configuration with fullwater reflection. These values are specified as the "solution critical mass" in Table 1. Deviations fromthe ideal conditions generally increase the critical mass. However, some moderators such aspolyethylene, actually decrease the maximum critical mass. As illustrated in the table, the critical mass ofthe solid metal is more than ten times that for the isotope in solution. Critical and subcritical mass limitsare provided in the table for nuclides in solution, metal, and moist-oxide forms. The moist-oxide massvalues are significantly greater than the solution and metal values. This is true for both the critical andsubcritical values, though only the subcritical values for moist-oxides are given in Table 1. The criticalmass limits correspond to a kat. of 1.0, where ker is the neutron multiplication factor for a finite system.The subcritical mass values correspond to a kej of 0.98.

d. ANSI/ANS 8.15, American National Standard for Nuclear Criticality Control of Special Actinide Elements, November 1981.

e. H. C. Paxton & N. L. Pruvost, Critical Dimensions of Systems Containing 235U, 239Pu, and 233U, 1986 Revision,LA-10860-MS, Los Alamos National Laboratory, July 1987, Figures 22-25.

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Table C-1. Minimum critical and l miting masses for fissile isotopes.

239pu 235U

233U

Critical mass:

Solution' 510 g 810 g 590 g

Metalth 5.3 kg 21.2 kg 7 kg

Subcritical mass limit:

Solution' 480 g 760 g 540 g

MetaP 5.0 kg 20.1 kg 6.0 kg

Moist-oxide (1.5-wt.% H20)k 10.2 kg 32.3 kg 10.1 kg

Mass limits are applied using a safety factor to incorporate a margin of safety. The actual limit iseither 75 or 45% of the critical mass depending on over-batching scenarios.'

1.3.2 RWMC Transuranic Waste

Due to the large quantity of waste in a disposal area, the total quantity of fissile isotopes is typicallyestimated at many times the minimum critical mass. The material is mostly dispersed at lowconcentration throughout the waste. Fissile isotopes exist primarily as contamination of the wastematerial. Items potentially containing larger amounts of fissile material, such as filters and graphitematerial, make up a small percentage of the total waste material.

Overloaded drums may be present among the waste. Of 17,000 drums recently assayed at theRWMC, 37 drums from the Rocky Flats Plant have been found to exceed the RWMC fissile loading limitof 200 g.m Eleven of those contain more than 380 g, which is 75% of the plutonium minimum criticalmass."

f. Paxton and Pravost, 1987, Figures 10, 31, and 36.

g. Ibid.

h. N. L. Pruvost & H. C. Paxton, Eds., Nuclear Criticality Safety Guide, LA-12808, Los Alamos National Laboratory, September1996, Tables 6 and 7.

i. Ibid., Table 1 (also ANSI/ANS 8.1).

j. Ibid., Table 3.

k. Ibid., Table 4

I. Criticality Safety Program Requirements Manual, Revision 1, PRD-112, LMITCO, June 1, 1998.

m. L. V. East, Suspect Drum Remeasurement Results, INEL-95/024, RWMC-800, March 1995.

n. Ibid.

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The RWMC assigns a content code to each waste container. For criticality safety purposes, thesecontent codes are grouped into eight waste matrices. A waste matrix can cover a range of materials.Table 2 lists the waste matrix designations and gives some examples of waste covered by each matrix.

Most of the RWMC overloaded drums that exceed 200 g of fissile material, but have less than380 g, have a cellulose waste matrix. Other waste matrices for drums at this fissile mass level includeconcrete, metals, and salt. The eleven drums that contain more than 380 g of fissile material have onlythree content codes, relating to glass/slag (crucible heels), cellulose (filter media), and salt (molten salt)waste matrices.°

The fissile isotopes occur in the waste as weapons-grade plutonium (-94-wt.% 239Pu), highlyenriched uranium (-93-wt.% 235U), 233U, and depleted uranium (-0.2-wt.% 235U). The depleted uraniumhas so little 235U that it cannot fission and need not be tracked as fissile material. Much of the fissilematerial is in oxide, nitrate, or hydrated-oxide form. Some plutoniurn is in metal form, specifically thatassociated with metal crucibles (metal waste matrix) and non-metal molds and crucibles (graphite,glass/slag waste matrices). Any plutonium or uranium disposed of in metallic form is expected to at leasthave an outer oxide film. Small metal pieces are likely to be completely oxidized.P

A calculative analysis of plutonium metal oxidation, both before treatment and during in situvitrification processing, has been completed.° It demonstrates that, at room temperature and 100%relative humidity, spherical metal particles less than 3.7-cm in diameter will completely oxidize in 26years. (All waste in the WAG-7 waste pits has been buried for at least that long.) Under these conditions,a particle 0.635-cm in diameter will oxidize in less than 5 years. It is reasonable to expect that waste hasbeen subject to high relative humidity at times, when it has been buried for more than 26 years. Uraniummetal is expected to oxidize in a similar fashion.

Table C-2. Listing of waste matrix designations.

Waste Matrix Examples of Typical Waste

Polyethylene Resins, organic sludge, combustibles

Cellulose Benelex, Plexiglas, cemented insulation and filter media, gloves

Brick Fire brick—scarfed, coarse, pulverized

Concrete Cemented and uncemented sludges

Salt Evaporated, molten, Gibson, direct oxide reduction salts

Metal Noncombustibles, noncompressibles, tantalum, lead, scrap

Glass/slag Glass bottles, crucibles, and molds, dirt, ceramic crucibles

Graphite Graphite crucibles, heels, and molds

o. G. K. Becker, Suspect Drum NDE/NDA Fissile Material Mass and Uncertainty Assessment, RWMC-708, July 1994.

p. A Comprehensive Inventory of Radiological and Nonradiological Contaminants in Waste Buried in the Subsurface D sposalArea of the 1NEL RWMC During the Year 1952-1983, Vol. I, EGG-WM-10903, June 1994.

q. R. K. Farnsworth, Calculation on Kinetics of Plutonium Metal Oxidation During 1SV Processing, September 1998, seeSection 2 of this appendix.

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1.3.3 In Situ Grouting

The grouting materials under consideration for in situ grouting include cementitious, mineralogical,polymeric, and paraffin substances. A drill string, approximately 10-cm in diameter, is inserted into thewaste. It is withdrawn in measured steps, with grouting material injected into the adjoining waste and soilat each step. This is repeated on a triangular pitch at 45- to 60-cm intervals throughout the waste pit.

As the drill string is inserted, the adjacent waste and soil will be compacted. This will be confinedto a thin region due to the small diameter of the drill string. Small amounts of grouting material will beinjected during the insertion. Drums and other waste containers will be punctured by the drill string.There will be a small amount of mixing of waste, soil, and grouting material, confined to a thin film alongthe insertion hole. The insertion of the drill string will induce only these local effects and will notincrease the reactivity of the waste pit.

The drill string, filled with grouting material, cannot mix intimately with the fissile material anddoes not behave as a moderator. It is an ineffective reflector. Due to its cylindrical geometry and smallsize, its interaction with fissile material will be minimal.

High-pressure (-6000 psi) injection of grouting material into the waste pit begins as the drill stringis withdrawn. The withdrawal is slow, with the drill string raised in 5-cm steps. At each step, groutingmaterial is ejected at high-pressure for 4-6 seconds from small nozzles. The jet-grouting process directlyaffects an area approximately 15-cm thick and 60- to 75-cm in diameter about the drill. The horizontalarea is about 15 cm greater than the drilling interval to ensure penetration of grouting material into allwaste and soil. The grouting material mixes most intimately with waste and soil within the drilling area.Due to the high-pressure injection of the grouting material, already-grouted columns are perturbed bysuccessive grouting activities. As void space is filled and the grouted areas settle, movement of groutedzones occurs. However, mixing of grouting material, waste, and soil occurs primarily adjacent the zonecurrently being grouted.

The mixing action fills void space in the soil, between waste packages, and within punctured wastepackages. Waste packages smaller than 55-gal drums may not be punctured by the drill string insertion.However, the force of the jet-grouting action may be great enough to puncture many remaining intactwaste packages. Any intact waste packages will maintain their internal void space, but will beencapsulated into the resultant monolith.

The hole created by drill insertion is closed by the jet-grouting process during drill stringwithdrawal.

Although there is movement throughout all fluid grouted areas, only a limited area is greatlyperturbed at any one time. The grouting materials under consideration all include significant amounts ofeither water or hydrocarbons; therefore, all can act as moderators and reflectors when mixed with thewaste and soil. This is particularly true for the paraffin and polymeric materials. However, they alsobehave as diluents in the fissile material matrix. The fissile density at any particular location will remainapproximately the same, however, so the overall material density will increase. As a result, due to thefilling of voids, the ratio of fissile material to other materials will decrease.

Of particular concern is the effect of injecting grouting material into an overloaded drum. So longas any one drum can be grouted safely, it is certain that the entire area can be grouted safely. Preliminarycalculations are complete for the minimum critical mass of 239pu mixed with paraffin and polymericgrouting materials. For a paraffin mixture, the minimum critical mass is 300 g, for a sphere 24 cm in

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diameter and 239PU concentration of 0.04 g/cm3. For the polymeric grouting agent, the min mum criticalmass is 490 g, for a sphere 30 cm in diameter and 339Pu concentration of 0.03 g/cm3.

Minimum critical mass values have yet to be calculated for the cementitious and mineralogicalgrouting materials. However, calculations for 339Pu mixed with soil have been completed.' For saturatedsoil (40 percent water) the minimum critical mass is 1.6 kg, for a sphere 54 cm in diameter and 33913uconcentration of 0.02 g/cm3. For soil with 20 percent water, the minimum critical mass is greater than4 kg. These results indicated that the masses for cementitious and mineralogical grouting materials willbe significantly greater than those calculated for paraffin and polymeric materials.

Further criticality safety evaluation is needed if paraffin or polymeric materials are used for in situgrouting. The preliminary calculations were conservative, not considering waste material other than thefissile material. Judicious use of a neutron poison in conjunction with these types of grouting materialscould allay criticality safety concerns, but would require rigorous assessment to ensure adequatedeployment into the waste and stability in the resultant waste form.

1.3.4 In Situ Vitrification

During in situ vitrification, the form of the soil and waste is changed chemically and physically.The melt has a temperature of about 1,600°C, advances at a rate of about 5 cm per hour, and isaccompanied by a steep temperature gradient. Volatile and semivolatile materials, and water, vaporize.Salts dissociate, forming oxide and vapor products. Organic materials undergo pyrolysis. Oxides areincorporated into the strong convective currents of the melt. Metals too large to be suspended in the meltsettle to the bottom in a metal sublayer. The waste materials incorporated into the melt undergosignificant homogenization. Data from a pilot-scale radioactive test involving a concentrated source withplutonium and americium isotopes show that concentrations of these isotopes were decreased by a factorgreater than 50 during in situ vitrification, by being dispersed throughout the in situ vitrification area.' Atin situ vitrification completion, the waste volume is reduced by 70 to 80%, with a resultant glass waste-matrix density of 2.4 to 2.8 Wcm3.

The criticality safety of in situ vitrification centers on the issue of whether the properties of thewaste change such that the reactivity of the system increases. Behavior of the fissile material and otherwaste components during in situ vitrification is examined below.

During pilot-scale and large-scale radioactive tests, over 99.9% of the plutonium and americiumwas incorporated into the melt.' Conversely, less than 0.1% was released to the off-gas system. With thishigh retention rate of fissile isotopes in the melt, a criticality accident would not be credible in the off-gassystem.

r. Soil calculations (DANT3.0) used 23131102 and representative INEEL soil, with theorhetical densities of 11.47 and 2.38 g/cm3,respectively. The soil composition was obtained from ISV Criticality Analysis of INEL Soil by Libby and Doherty,INEL-90-002. They were mixed at various 239PU concentrations, from 0.01 to 0.10 g/cm3. A 30-cm water reactor surrounded the239Pu02 and soil sphere. Critical sphere diameters varied from 40 to 75 cm.

s. C. L. Timmerman & K. H. Oma, An In Situ Vitrification Pilot-Scale Radioactive Test, PNL-5240, Pacific NorthwestLaboratory, October 1984.

L. Ibid.

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There are three possible forms for plutonium (Pu) and uranium (U) at the start of in situvitrification: oxide, salt, and metal. Pu and U are thermodynamically stable in the oxide form. Typicalsoil compounds such as silica, iron oxide, and alumina are more likely to reduce to metal before Pu and Uoxides would reduce. The fissile oxides are nonvolatile, with low vapor pressures and melting pointsgreater than the in situ vitrification melt temperature. They are highly soluble in glass. The meltadvances slowly, so oxides at a particular location have adequate time to dissolve and mix into theconvective currents as the melt proceeds through the waste.

Plutonium and uranium salts will dissociate as temperature rises along the melt front. Thenegatively charged ion — e.g., halide, nitrate, carbonate, and sulfate — will vaporize. The positivelycharged fissile ion will oxidize. Once in oxide form, behavior is as described above.

A preliminary analysis has been performed that demonstrates that buried plutonium and uraniummetal pieces will completely oxidize during the in situ vitrification process.0 As discussed earlier, smallmetal pieces will already have oxidized before the start of in situ vitrification. Metal particles as large as3.7-cm in diameter may also already be completely oxidized, and will be at least partially oxidized. Dataindicates that as temperature rises, oxidation rate of the metal increases. Remaining small metal pieceswill completely oxidize and dissolve into the melt in a short time. Even if a metal piece as large as aplutonium button (3 kg) was present in the waste, the duration of the in situ vitrification melt and coolingperiod is sufficient to ensure oxidation and incorporation into the melt.

Concerns associated with the nonfissile waste material include the effect of water being drawn outof the waste matrix, whether matrix material will become more moderating or reflective during in situvitrification, and the effect of new void space introduced during in situ vitrification. Soil, water, andwaste matrix materials given in Table 2 are addressed.

A high-temperature zone will advance before the melt front. This will draw water out of the wastepit, decreasing moderation in the waste matrix. As indicated in Table 1, the minimum critical mass offissile material increases greatly as moderation decreases.

Waste matrix materials that represent effective moderators and reflectors include polyethylene,cellulose, and graphite. These will be eliminated from the waste during in situ vitrification by combustionor some combination of volatilization and destruction. Polyethylene-type materials may melt beforevolatilization. Polyethylene is a more effective moderator than water, and as it melts, it could mix withfissile material. However, it is not likely to concentrate with fissile material to any extent because it willcontinue to flow until it volatilizes. Another favorable factor is that none of RWMC drums determined tobe overloaded contain polyethylene matrix material. However, drums with other matrix materials stillcould have polyethylene liners and bags. Some examination of polyethylene behavior during in situvitrification is needed, particularly its fluidity and ability to entrain fissile material. If it is shown thatpolyethylene is unable to transport fissile material due to low viscosity, quick volatilization, or othercharacteristic, it can be dismissed as a criticality safety issue.

Beryllium is another material that moderates and reflects well. If beryllium metal is subjected to insitu vitrification, it is expected to oxidize and dissolve into the melt. Beryllium waste was typicallydisposed of in the Low-Level Waste Pits and not associated with fissile material." If significant quantities

u. R. K. Farnsworth, Calculation on Kinetics of Plutonium Metal Oxidation During 1SV Processing, September 1998 draft.

v. R. K. Farnsworth, Fate of Contaminants During In Situ Vitrification Processing, June 1998 draft.

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of beryllium are present in a transuranic waste pit or trench, further evaluation is required to ensurecriticality safety.

Dried soil will be incorporated into the melt. Metals that do not oxidize, or materials that arereduced to elemental meta] form, will melt and settle in a separate metal layer at the bottom of the melt.Dried concrete and brick will be incorporated into the melt. Glass and slag materials will be incorporatedinto the melt. Salts will undergo a combination of volatilization and destruction.

As materials volatilize or transform as the temperature gradient moves through the waste, new voidspace is temporarily created, and slumping of remaining material will occur. Due to the structureprovided by soil, brick, concrete, and metal containers, physical arrangement of the remaining materialwill remain essentially unchanged until actually contacted by the melt front. The fissile material needs tobe concentrated in order to achieve a critical mass, as moderator leaves the waste. When the fissilematerial is reconfigured as it enters the melt, its critical mass escalates. Preliminary calculations showthat a plutonium concentration of 2.9 g/cm3 is required to achieve criticality when homogeneously mixedwith glass, in a sphere with a 30-cm diameter.' This corresponds to a 239PU mass of 41 kg. A massiveconcentration of plutonium throughout a waste pit would need to occur to approach a critical mass.

Due to the convective currents, any materials incorporated into the melt are disperse. The longer amaterial remains in the melt, the more homogeneously it will be distributed throughout the resultant glassmatrix. So long as the uranium and plutonium dissolve into the melt, concentration will not occur and thecriticality safety of the system will be favorable.

1.3.5 Pretreatment Options

Four pretreatments are proposed for in situ vitrification, to be used singly or in combination tomake the waste pit configuration more favorable to in situ vitrification.

1.3.5.1 ln Situ Disruption. The purpose of in situ disruption is to puncture waste containers anddecrease void space. A vibrating rod or beam is driven into the waste pit at about 60-cm intervals, thenwithdrawn. Some localized compaction will occur during insertion, as will a small amount of mixing.The extent of the compaction is dependent upon the size of the disruption tool. The mixing will belimited to a thin layer along the insertion hole, and will not affect the reactivity of the system. Thevibration will induce some movement of waste into void spaces, but not act as a mechanism for mixing.

If open holes are left by the disruption tool, the tool size and spacing configuration will need to beassessed for criticality safety. Open holes may introduce new criticality safety concerns during the in situvitrification process. They are potential collection areas and pathways for fissile material and moderators,possibly leading to reconfiguration into a more critically favorable state. If open holes do not remain afterin situ disruption is complete, it is concluded that dynamic disruption will not significantly affect thereactivity of the waste. Holes could be filled by the action of withdrawing the disniption tool, orintentionally after the disruption process.

w. Calculations (ONEDANT, 02-05-90) used typical INEEL soil as specified in INEL-90-002, 1SV Criticality Safety Analysis of1NEL Soil, by R. A. Libby & A. L. Doherty, September 1990. Water was removed from soil; remaining oxides were adjusted tocompensate and the resultant mixture was used at a density of 2.8 g/cm3, to represent glass. 239Pu02 was mixed with the glass atvarious 239P11 concentrations, from 0.015 to 10 gicm3. A 107-cm saturated (40% H20) soil reflector surrounded the 239Pu02 andglass sphere. Critical sphere diameter was as low as 14 cm, for 239Pu at 9.6 gicm3.

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1.3.5.2 ln Situ Thermal Desorption. Multiple 15-cm diameter rod heaters are inserted into the wasteat approximately 2- to 3-m intervals. The rods are slowly heated, which drives off water, degrades salts,causes combustibles to pyrolize, drives off volatile and semivolatile materials, and promotes oxideformation.

The rod insertions for this pretreatment are adequately covered by a letter that allows up to 15.4 cm(6-in.) diameter holes at an edge-to-edge spacing at least 1.5 m (5 ft)." The heating process induceseffects that are similar to those for in situ vitrification. New void space is introduced into the waste andsoil due to the vaporization and pyrolysis. Consequently, some slumping will occur in the waste andfissile material density will increase. More importantly, moderators are removed by the heating action.The waste and soil will not be mechanically rearranged, essentially maintaining their originalconfiguration. The only possible criticality scenario involves polyethylene, as described for in situvitrification. Before it can be concluded that this operation will not significantly affect the criticalitysafety of the waste, the polyethylene issue must be satisfactorily resolved.

If moderation in the form of moisture can be reintroduced to the waste area, the criticality safety ofthe new waste form would need to be evaluated for criticality safety evaluation.

1.3.5.3 ln Situ Stabilization. In situ stabilization is the same as in situ grouting, but would use only acementitious or mineralogical grout. The discussion for in situ grouting also applies to this pretreatment.Use of cementitious and mineralogical grouting materials is acceptable with respect to criticality safety.

1.3.5.4 Dynamic Compaction. For this pretreatment, a heavy weight, about 4 metric tons, is droppedonto the waste pit from a height of 4 to 8 m. This is repeated at intervals of about 1.5 m and until nosignificant change in surface height is detected.

The dynamic compaction process compresses the waste by about 45%. Void space is reduced byabout two-thirds. Some mixing of materials could occur as void space is filled. Compaction of the wasteincreases its density. Although the ratio of fissile material to matrix material and of waste to soil isunchanged, by the density increase, moderating and reflection effects will increase and the reactivity ofthe system will increase. This process requires further evaluation for criticality safety.

x. D. J. Henrikson, letter DXH-01-98 to A. G. Ramos, Criticality Safety for Probehole and Corehole Drilling at Pit 9, LMITCO,March 1998.

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2. CALCULATION ON KINETICS OF PLUTONIUM METAL OXIDATIONDURING IN SITU VITRIFICATION PROCESSING

R. K. FamsworthSeptember 25, 1998

As part of the in situ vitrification preliminary criticality safety study, questions have been raised onwhether a large particle of plutonium metal, buried in the waste, would have sufficient time to oxidize andbe incorporated into the "glassf portion of the in situ vitrification melt, or if it would settle out in themetal layer at the bottom of the melt. This calculation provides information on the kinetics of plutoniumoxidation during in situ vitrification processing.

First off, standard waste disposal practice was to not purposely dispose of significant pieces ofplutonium metal in waste, due to its high value and potential ease of recovery. However, waste streamsthat included molds and crucibles are expected to have included metal plutonium contaminants.Therefore, the only size particles that may have been disposed of would be those that were either missedduring recovery, or adhered to the waste molds and crucibles.

To envelop plutonium metal contaminants, we have decided to look at three sizes of sphericalplutonium metal particles. The three different size particles have diameters of 0.25 in., 0.5 in., and 1 in.,respectively, to reflect the so-called "largest particle that may have been disposed of in the RWMC pitsand trenches." As the particle size increases, it is increasingly unlikely that such a particle wouldintentionally have been disposed of.

The 0.25-in. diameter particle has a total volume of 0.134 cc. At a density of 19.816 g/cc, the totalmass of the particle is 2.66 g. The total surface area of the particle is 1.27 cm2.

V = (0.635 cm)3 x 7r / 6 = 0.134 cc

M = V x 19.816 g/cc = 0.134 ccx 19.816 g/cc = 2.66 g

SA = (0.635 cm)2 X 71. = 1.27 cm2

The 0.5-in. diameter particle has a total volume of 1.07 cc. The total weight of the particle is21.3 g. The total surface area of the particle is 5.07 cm2.

V = (1.27 cm)3 x 7T / 6 = 1.07 cc

M = V x 19.816 g/cc = 1.07 cc x 19.816 g/cc = 21.3 g

SA = (1.07 cm)2 x 7T = 5.07 cm2

The 1-in. diameter particle has a total volume of 8.58 cc. The total weight of the particle is 170 g.The total surface area of the particle is 20.3 cm2.

V = (2.54 cm)3 x 7r/ 6 = 8.58 cc

M = V x 19.816 g/cc = 8.58 cc x 19.816 g/cc = 170 g

SA = (2.54 cm)2 x7r = 20.3 cm2

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It is likely that any plutonium metal particles disposed of in WAG 7 would have irregular shapes.However, for our cases, a sphere is chosen since it represents the "worst case condition, in terms ofhavinu a minimum surface area available to oxidation, relative to the size of the particle. As a result, thisalcc .aion represents "worst-case corrosion conditions for particle sizes of 2.6 g, 21.3 g, and 170 g,

respectively.

In addition, criticality safety has asked, as a bounding case, that we also look at the oxidationkinetics of a 3-kg plutonium button with approximate dimensions of 3-in. in diameter and 1.3-in. thick.While the sphere calculations look at the issue of small- to medium-sized metal particles being buried inthe pit, the plutonium button evaluation assumes an accidental disposal. It also presumes that oniy one ofthese buttons would exist in a particular melt. The critical dimensional parameters associated with such abutton are as follows:

V = (1)4) x(3 in. x2.54 cm/int x(1.3 in. x2.54 cnVin) = 151 cc

M = V x 19.816 g/cc = 151 cc x 19.816 g/cc = 2984 g

SA = x (3-in x2.54 cnihn) x (1.3-in x2.54 cm/in)]

+ 2 x We 4) x (3-in x2.54 cm/in)2] = 170 cm2

Based on the Plutonium Handbook (ANS 1980), it appears that plutonium metal will oxidize atroom temperature rather rapidly, if in the presence of ordinary laboratory atmospheres (p. 147). Inaddition, oxidation is accelerated in the presence of water vapor, and decelerated in the presence of dry air(p. 147). In fact, the presence of moisture in inert gases appears to be more conducive to plutonium metaloxidation than moist air itself. This is illustrated by a test in which unalloyed metallic plutonium wasplaced in atmospheres of helium and air, both with moisture contents of 50%. In the moist inert gas, theextent of oxidation was 60 times as large as in moist air (p. 153).

In evaluating these data's applicability to plutonium metal buried in WAG 7, it seems safe toassume that the typical burial environment for the metal would be in an area of significant moisture, aswell as in an area of limited air. Therefore, it is suspected that most of the metallic plutonium disposed inWAG 7 will likely have already oxidized.

Table 6.1 of the Plutonium Handbook (ANS 1980, p. 152) gives an indication of the kinetics ofplutonium oxidation, at 100% relative humidity and room temperature (25°C). The table shows anapproximate weight gain of 6.5 mg/cm2 over 900 hours. For plutonium-239 metal conversion toplutonium-239 oxide (Pu02), 1 g of plutonium is oxidized to a plutonium oxide mass of:

(1 g Pu) x(271 g/mole Pu02) / (239 g/mole Pu) = 1.134 g Pu02

or 1 g Pu, oxidized, produces a 134 mg weight gain

for each particle, the following calculations can then be made

0.25-in. diameter particle

2.66 g Pu x(134 mg wt gain/g Pu)+ [(6.5 mg/cm2) / 900 hr] x(1.27 cm2)) = 38,860 hrs

= 4.4 yrs

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21.3 g Pu x(134 mg wt gain/g Pu) 4- ([(6.5 mg/cm2) / 900 hr] x(5.07 cm2)) = 77,950 hrs

= 8.9 yrs

1-in. diameter particle

170 g Pu x(134 mg wt gain/g Pu) ([(6.5 mg/cm2)/ 900 hr] x(2a3 cm2)) = 155,400 hrs

= 17.7 years

Plutonium Button

2984 g Pu x(134 mg wt gain/g Pu) ([(6.5 mg/cm2)1 900 hr] x(170 cm2)) = 325,700 hr

= 37.2 yrs

The wastes in the WAG-7 waste pits have been buried for at least 26 years (Arranholz and Knight1991, Table 12, Pit 12). Using the same calculation as before, the limiting size of an oxidized particle,after 26 years of burial, would have a 1.463-in. diameter, and a total weight of 532 g. It then stands toreason that any metallic Pu-239 particle smaller than 1.463-in. in diameter (and 532 g) that is placed intoWAG 7 should be completely oxidized. Plutonium particles larger than 532 g could also be completelyoxidized, provided they were buried before 1972. In addition, any plutonium buttons (2984 g) buriedbefore 1962 should also be completely oxidized. Furthermore, since the surface area of the unoxidizedmetal shrinks over time as the oxidized plutonium flakes off, even the plutonium button may have fullyoxidized, since the above calculations do not account for the shrinking surface area of each particle ofconcern. Similar rates of oxidation would be expected for uranium metal, the other potentially fissilematerial in the waste.

The plutonium oxidation calculation assumed a relative humidity of 100% during burial and thatoxidation occurred at a steady-state rate—unaffected by oxide buildup on its surface. This analysisbreaks down, however, if the metallic particle does not encounter a 100% relative humidity environment,or the oxide layer on the oxidizing particle retards the rate of oxidation that is experienced, due to limitedexposed surface area and mass diffusion limitations. In addition, the particle could be disposed of in anenvironment (such as oil) that limits the particle's exposure to oxygen-bearing materials (such as air orwater).

The Plutonium Handbook (ANS 1980) states that the oxidation reaction is under anodic control(p. 151), and that the oxidation reaction is augmented by extensive disintegration of the metal into smallfragments (p. 152). However, very little information is available on how much surface degradationoccurs during surface oxidation.

Although it seems highly unlikely, assuming that the lack of material exposure to oxygen-bearingmaterials is a problem for some buried plutonium metal, an alternative calculation can be used to definethe rate of oxidation for such a particle, as it is heated to melting during in situ vitrification. Uponmelting, it can be safely assumed that the molten plutonium will become exposed to an oxidizingenvironment, as it flows away from the oxide cnist.

Figure 6.34 of the Plutonium Handbook (ANS 1980, p. 172) shows the Iinear oxidation rate forunalloyed plutonium metal, as a function of temperature. As shown in the figure, plutonium metal

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exhibits a linear rate of oxidation of approximate]y 1200 tig/cm2-min at temperatures of 550°C. Inaddition, the figure shows the linear rate of plutonium oxidation at 450°C is approximately 100 pg/cm2-min, and that there is a linear correlation between the log of the linear rate of oxidation and the inverse ofabsolute temperature, within this high-temperature regime. Based on this, it appears safe to extrapolatethis oxidation curve to define what the linear rate of oxidation would be at the melting rate of plutoniummetal (639.5°C):

Temp.(°C)

T

(°K) 100/TLog(Lin. OX.

Rate)

Lin. Ox. Rate

(µg/cm2-min)

450 723 1.383 2 100

550 823 1.215 3.08 1,200

640 913 1.096 see below see below

Log (Linear Oxidation Rate) at 640°C = 1.096 —1.215)

x (3.08 — 2) + 3.08 = 3.84(1.215 —1.383)

Linear Oxidation Rate at 640°C (extrapolated) = 6,900 µWen-12-min)

As the in situ vitrification melt front moves downward during in situ vitrification processing (orsideways in the planar-in situ vitrification configuration), any plutonium metal in the waste will melt at640°C, approximately 3-5 cm away from the in situ vitrification melt front (assuming a temperaturegradient of 150°C/cm of soil (Campbell, Timmerman and Hansen 1996) and a melt-front temperature of1100-1400°C). Once molten, the plutonium metal would sink by gravity away from the in situvitrification melt front until it recondenses. With the steep temperature gradient observed during in situvitrification processing, this would most likely occur within 0.5 cm of the melt. The melting ofplutonium should therefore allow for any plutonium metal in the melt to constantly reside at a temperatureof 640°C, throughout in situ vitrification processing.

Although it is probable that the molten plutonium metal will assume a thin slab-like form, andtherefore have an increased rate of oxidation, due to the higher surface area to volume ratio of a slab, theforegoing evaluation conservatively assumes that the molten plutonium particle or button maintains itsoriginal spherical or cylindrical geometry during in situ vitrification processing. It also does not accountfor shrinking surface area as oxidation proceeds. With these conservative assumptions in place, thefollowing calculations are made showing the time at which the hypothetical sphere particles and buttonare oxidized at the melt temperature.


2660 mg Pu [(6.9 mg/cm2-min) x (1.27 cm2)] = 303 min

= 5.1 hr at 640°C


21,300 mg Pu [(6.9 mg/cm2-min) x (5.07 cm2)] = 609 min

= 10.1 hr at 640°C

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/70,000 mg Pu [(6.9 mg/cm2-min) x (20.3 cm2)] = 1214 min

= 20 hr at 640°C

Plutonium Button

2,984,000 mg Pu [(6.9 mg/cm2-min) x (170 cm2)] = 2543 min

= 42.4 hr at 640°C

At a more conservative oxidation rate of 1.2 mg/cm2-min (the recorded rate of plutonium oxidationat 550°C), the 0.25-in, 0.5-in, and 1-in. diameter particles would completely oxidize after 29.1 hr, 58.3 hr,and 116 hr, respectively. In addition, the 2984 g plutonium button would oxidize at 550°c after 244 hr.

For a typical in situ vitrification melt, the time to melt the entire contents of a pit 20 ft deep wouldbe 10 days or 240 hours. This averages out to a rate of downward melting of 1 in./hr. Using thesubcritical mass limit of 5 kg for 229Pu metal, the 0.25-in., 0.5-in., and 1-in. diameter spherical particleswould have to be at the following calculated densities to cause a criticality concern during the in situvitrification melt.


5000 g Pu ± 2.66 g Pu/particle = (5.1 hr x 1 in./hr)

= 369 such particles every inch of melting (across a 900 ft2 cross section)


5000 g Pu ± 21.3 g Pu/part cle ± (10.1 hr x 1 in./hr)

= 23.2 such particles every inch of melting (across a 900 ft2 cross section)


5000 g Pu = 170 g Pu/particle = (20 hr xl in./hr)

= 1.5 such particles every inch of melting (across a 900 ft2 cross section)

These particle densities are not at all realistic. Even if these particle densities could be achieved,the material would have to assume a perfect spherical geometry to approach a critical state.

A secondary concern to be addressed is the chance of a critical condition occurring as waterpercolates back toward the melt, following processing. However, it is expected, after in situ vitrificationprocessing is completed, that the 600°C isotherm temperature will exist for at least an additional 240 hrs.In addition, limited convection is expected to continue in the in situ vitrification melt, after electricalpower is terminated and the melt starts to slowly cool. As a result, any residual metallic plutonium willbe fully oxidized and incorporated before water can percolate back into the melt area.

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As previously stated, it is not likely, even by accident, that a plutonium metal piece so large as aplutonium button exists in the buried waste. Even a much smaller 1-in. diameter spherical particle wouldbe in the buried waste only by accident. Nevertheless, for conservative purposes, the oxidation of theselarge plutonium metal pieces was explored. As shown in the above results, it appears that an increasedpotential exists for a buried plutonium button not being fully oxidized during in situ vitrificationprocessing. However, considering the long burial time and the additional time at elevated temperatureafter in situ vitrification, it is reasonable to conclude that a metallic particle as large as a button would becompletely oxidized by the end of the post-in situ vitrification cooling period.

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3. REFERENCES

American Nuclear Society (ANS), 1980, Plutonium Handbook: A Guide to the Technology, Vol. 1,American Nuclear Society, La Grange Park, Illinois Oz Wick, ed.).

Arranhoz, D. A., and J. L. Knight, 1991, A Brief Analysis and Description of Transuranic Wastes in theSubstoface Disposal Area of the Radioactive Waste Management Complex, EGG-WTD-9438,EG&G Idaho, Inc., Idaho National Engineering Laboratory, Idaho Falls, Idaho.

Buelt, J. L., C. L. Timmerman, K. H. Oma, V. F. Fitzpatrick, and J. G. Carter, March 1987, /n SituVitrification of Transuranic Waste: An Updated Systems Evaluation and Application Assessment,PNL-4800 Supp. 1, Pacific Northwest Laboratory, Richland, Washington.

Campbell, B. E., J. E. Hansen, and C. L. Timmerman, 1996, "In Situ Vitrification (ISV): An Evaluationof the Disposition of Contaminant Species During Thermal Processing," Presented at the 15thInternational Conference on Incineration and Thermal Treatment Technologies, May 6-10, 1996,Savannah, Georgia.

Hilliard, D. K., and C. H. Kindle, 1991, ISV Safety, Processing and Starter Path Issues, PNL-7684,Pacific Northwest Laboratory, Richland, Washington.

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