LA-lJR -91-2976

●

DE92 000213

Los Alamos Mllonal Labomloq . omarwd tw Iho Unwwmw ~ C-llfornm for IM UnM SlaIwSDewmwnl of Enow under comfmcl W-7405 -ENG44

!Mived byOSTI.Ocr041991

TITLE: ADDRESSINGI!IXEDI?ASTEIN PLIJTONILWPROCESSING

AUTHOR(SK D. C. Christensen,C. L. Sohn,and R. A. Reid

SUBMITTED TO: Am-lean ~hemlcal society!Atlanta,GAOct. 1-3, 1991

DISCLAMER

l%iammflwweoremrd mewra-nlofwork moneoraf byanuerrcyofthe Unlted!h!uChwernkent, Nklh he Unltd SIda Wvernn&M nor ●ry qsm-y Itkf, nor wry of heircmployoee,m-ha wry wmrsmy, ●ar w Implid, or euurnee mry Iesd Ihbllhy w reqmrrsl.bllhy for Ihe ecwmcy, uwnfdelc~ of umhdrw of mry Informdkn, ●p@rduh prducl, or~ diwM, w repmwnh Ihd ih uw would noi infrin~ privntaly ownuJ righl-. RAr-anw twain to my s~ifk mrmmemini prtdud, p~, or Mmka by Ire$e name, Ire&mark,mmrufeclumr, ,Wdhwrwlm &me nd rramumlly arnslllule or imply 11serdommonl, recamnmnddkm, IX !cvorlng by he [Jnhal Wet- (Jwvwnmenl or eny •~ncy lherwf. The dewsd apinlum d aukm expfaeai hemln do nd newuearily 91ele of re(lect Ihcmsof thtUnkd SIeleo (brarnrnenl or my apcy Ihnrmfo

Ih@ pubhshof rccngnitos Ihal lhn 11S Oovcrnmanl rmlmnma nonwacluslva fnymlly has hcermo 10 publlsl! or !apruduco

lLOSAhlllilOSLosAlamos,NewMexico87545Los Alamos National Laboratory

WNm DISTHIW.JIION or lot!IS DOCUMEPJ I IS LJNLIMITED ~

Dana C. Christ.nmn●nd

C~rOl L. ~OhNualoar Natmials Taobnology Division

Los Aluos htional LaboratoryLos Alamom, MM 07S4S

505-6c7-ass6

Riohard A. RidAndormon Oahool of Naxmgamont

University of Now MoxiooAlbuqumqw, NM .7131

sos-a77-3oaa

ADDRESSING MIXED WASTE IN PLUTONIUM PROCESSING

Dana C. Chri8t9nmn

Carol L. SohnNuclaar Natarials Tmcbaoiogy Division

Los AlamocINational MboratoryLos Ahmm, W 87545

505-667-2556

Riahard A. RaidAndormon Sahool of Xa.aagamnt

University of Maw MxhoAlbuquorqu, MU 87131

505-a77-3oll

ADDRESSING MIXED WASTE IN PLUTONIUM PROCESSING

INTRODUCTION

For the past forty years, multiple facilities throughout the

Department of Energy (DOE) Complex have produced nuclear weapons,

processed recoverable residues, and genoratad a variety of waste

materials. Today, the Complex is comprised of 13 government-

ownod and contractor-operated installations. It in organized

into three functional elements: Sacilitios for ~roducing nuclaar

materials, laboratories and tasting ●ites, and plants for

producing non-nuclaar components. Although these facilities havo

always baan concamed with wamte products and msterials, the

●volution of tougher regulations and stiffer ponaltios along with

●scalating costs of wasto disposal has producod a graater focus

on tho wasto minimization and mnagament problam.

In tha proc~ssing of nuclaar mata%iala, sewral types of

wasta forw ●xist that includo both radioaetiva ●nd non-

radioactive ●lamants. Waatao can ba aonaidara(lhasaxdous if (1)

thqf ●rt spocifiaally listad by tho Environmental Protoctioa

Agancy (EPA) as hazardous, or (2) thay axhibit ● special

characteristic such as correaivity or texicity. If 8 WaStO i8

hasardous, tho EPA has ●txiatar ssquiramantu regarding it-

charaatorisation troatmant, ‘ltoraso,and burial, tharaby

increasing tha disposal uost to Ltu gmarator. A major aoncmn

today is with “mixad waste” whiah hm Km dafined by tha BPA ●s

● radioaotiva wasta with ● Easardou@ oomponant that is subjaat to

tha XPA’S Ramourco Consamation ●nd R@aovory Aat (RCRA)~ ●btitla

C rogulationso

2

Within the DOB Complex, mixad waste im or has been generated

at the production facilities at Pinellas, Mound, Kansas City, Y-

12, Rocky Flat8, Savannah River, and Pantex) the National

Laboratories at Los AlamoB, Bandia, and Livermore~ and the Nevada

Teat Site. Since DOE did not recognize the EPA’8 participation

in the management of mixed waste until 1907, it io con8idexed to

be a relatively new concern.

MBTHODOLOQICAL APPROACH

Although an overall goal is the minimisation of all waste

generated in actinide processing facilities, current emphasis is

directed tmard reducing and managing mixed waste in plutonium

processing facilities. Moro specifically, the focus is on

prioritizing plutonium processing tachnologias for development

that will address major problams in mix-d waste management.

A five ●top methodological ●pproach to identify, analyze,

solve, and initiats corractiva ●ction for mixad waste problems in

plutonium processing facilitim has bean dovolopod. A brief

description of this ●pproach follows:

1. Idantify tho Major Problams in Mixed Wcsta Management atPlutonium Procacsing Faailitiosl

a.

b.

a.

d.

Dwalop ● promss flow ●haat that dosc!ribasourrantproduat fabrication, #@rap roaovery, and wasteminimisation ●nd mana~amant operations.

Identify ●p-oifio mixad wasta management goals forprooassing faailitios.

Comparo uurrant parfomana, with dasirod parfomancamixmd waata managomont.

Probl@ms are indioatod when thara i- a discrepancybatwaen ●ctual ●nd denirad perfomanae.

in

3

2. Prioritize tha Major Pxoblems~

a. Identify criteria to ba u-ad in ●stablishing problampriorities.

b. Use the paimviso comparisons faature in EXPERT CHOICE(EC)* On the criteria to assign importance weights toeach criterion.

c. Use l?cto compute problam priorities through pairwisecomparison of each problem relativo to each criterion.

3. For tho Problem with tho Highest Priority:

a. Identify betwaen 2 and 5 altornativo solutiontechnologies.

b. Specify relevant critarla for @valuating the●ffectiveness of tha alttrnativa solution technologies.

c. Use EC (pairwis@ comparisons) to ●ssign importanceweight- to criteria.

d. usc EC to rank altornativo problam solutions throughpairwiso co~arison.

4. Rapoat 8tap 3 for Bach of tho Major Froblamm

5. D.volop and ●valuat@ a procass flow shoot that incorporatestho most dosirod ●olutiona to all of the major problezwidontifiod in stop 3 abovo.

● . Creata and vali&ata an analytical modal to imltato thobahavior of th- now procom flow shaot.

b. Usa tho modal to tast tho now proooss configuration foroperational feasibility and potontial mataria~ flowbottlanacks by mnning ● variety of ‘what-if” scmarios.

c. Us@ tho roaulta of tha modgling ●xoreiso to modify theproposad flow #ha@t.

d. Implomont tha resultant flow ●heat whioh promotos anintograt-d sat of plutonium fabrication, scrap/r@siduarQcov@ry, ●nd wmta minimisation/managamant Proeasmas.

Sworal advantages ●ra associated with ~hc usa of thim

methodological framwork. Pirst, an opuational definition of a

Wxad wasto problcm is providad in stap 1. That is, ● problam-.-----..-----------● WPERT CHOICE (EC) is ●n USOr-frhXidlycoftwara paakago forimplamanting tho Analytic Hiararchy Proeoss methodology umd insolving eomplox problams involving multiplo parformanoo critaria.

4

exists when current levels of performance● in wamta managamant are

below stated goals for the processing facility. Both the amount

of tho performance discr~pancy and the typa of mixed waate

involved should be used when determining whether or not to label

a problem as “major-. Second, since there is always a Iimitad

amount of managerial time and energy available for problem

solving, a systematic procedure to datarmine problem priorities

i- desirable. Third, a quantitatively-based mathod for

aggregating the ramkinga

alternative solutions to

probability of selecting

of an analytically-based

flowahaet performance of

of different performance criteria on

the major problems will increase the

the bast ●lternative. Finally, the use

integrated modal to ●ssess tho overall

all the bamt solution alternatives

●llows tha linkages or Mxrfacas batwaen proposed facility

processes to be ●valuated before implamantation ocsurs.

Zhe intarrela~ionships between the these flva SC-pm are

diagrammatically illustrated fin~igura 1. It is important to

nota tho i:arative natur~ of this ●pproach, ●s dopictad in t-he

third and fourth stops, for prioritizing tho ●ffoc~ivenass of

mambars of ● set of altarnativs procosc tochnologiss for a

particular problem. This focus on tha selection and/ox

devolopmant technologies for tha molution of mixed wast~ problem

ia ● koy charactoriatia of this problam-drivan methodology.

The use af the ~lytia Hicrarahy Process [AMP) is also

supportive of this probl~m-oriantad aathodolouiaal foaus.

Basiually, AMP is a mathod for stmcturing a aowlex decision

making problam into its oomponant partaf arranging thssa parts

into ● hlararchic ord~rl ●ssigning quantitative #cores that

5

measure the relative importance of each criteria on the decision

goal~ and synthesizing the analytical assessments into an

aggregated performance measure for each of the competing

alternative solutions. EXPERT CHOICE (EC) is an user-friendly

software package for implementing AHP Methodology. Since moat

problems involved multiple (tangible and intangible) criteria, EC

was used to enforce a coheelvo thought pettarn on the part of the

analysts as they geek to identify the best alternative.

The next section illuotrateg the use of the EC computer

software package to develop weights for the various performance

criteria ●ccording to their perceived importance, systematically

●valuate all altamativo procssaes againat each criterion, end

aggragate the individual criteria scores into a composite

perfo~e measure for ●ach of the candidate process

technologies.

AN ILLUS~TION

Assume that newly defined wasto management goals have been

davaloped for the IJNL plutonium processing facility. Current

performance levals indicata that th~ goal for mixad waste

generation is not being met. This problem is to be addressed by

salecting ● metal shaping procoss that will reduce the generation

of mixed waOte. Bach of tho components of step 3 art illustrated

for this scenario.

~eD 3aU Three altornativo metal shaping solution technologies:

1. Wrought Process

2. hloarNot Shape Casting

3. Net Shapa Casting

6

The wrought process involvas taking flat plates of plutonium

and rolling them into sheets. The sheet- are then hydroformed

into the desired hemispherical shape. Both the rolling and the

hydroforming processes involve the use of machine oils as

lubricant with the subsequent requirement to clean off the oils

with organic solvents such as carbon tetrachloride. Finally, the

hemispherically-formed components are processed to final contour

~loying the traditional machining techniques which uoe flood-

cooling of the cowonent w-ithoil-based coolants. The oil flood

cooling approach requires tha use of largo amounts of oolventa to

remove the oil from the final machined components am well as from

tha glovebox enclosures and processing equipment.

An altornativo technology, tha near not shape casting

process, utilizes the diract casting of plutonium into the

required hemispherical shape followed by the machining. This

proce~sing alternative avoids the need to roll and hydroform.

Although there is a significant reduction of mixed waste on an

unit oporation level, the impact on tha mixed waste generation

and disposal problem is fairly modost.

The third fabrication tochniquo, n~t ●hap. casting, involves

casting tho plutonium vaxy closaly to tha final spmcifiod contour

●o that rolling, hydroforming, and moot of tha machining

oparationa are ●liminatad. Again, th~ gan@ration of mixed waste

is further r~duced, although from an ovarall plant pormpectiva,

tha improvamant is modast. Sinco this technology is ralativoly

now ●nd still wolving, th~ro is moro uncertainty surrounding its

rcportod porformanco than that ●ssociated with tha two fomer

altornativos. Thus, ●ven though it ●pp-ars to produca the

7

smallest amount of mixed waste, it may be inappropriate to

conclude it is Lhe best metal shaping process.

Although each of the threo technologies could be used for

foxming the required plutonium c-nents and each has both

desirable and undesirable attributes, it is not obvious which

should be selected. UP provided an organized framework for

syst-tically evaluating tho preferred al’carnative.

step 3b. Tb.reerelevant criteria:

1. ~t of Mixed Waste Generated

Pour Subcriteria each representing one of the four types ofmixed waste generated:

a) Kg of Low Level Solid Mixed Waste per kg of metal produced

b) Kg of TRW Solid Mixed Waste per kg of metal produced

c) Kg of Low Level Liquid Mixed Waste par kg of metal produced

d) Kg of TRW Liquid Mixed Waste per kg of metal produced

2. Difficulty in Disposing of Mixed Waste that is Qenerated

Five SubCriteria ●ach associated with minimizing the impactof mixed waste diapoaal:

a) Technical Maturity - the more technically mature the metalshaping process, the greater tha confidence in the validity oftha waste ●stimates presented.

b) Complexity - th~ greatgr tho number of diff~rent types ofmixed wasto g~narated by a metal shaping procoss, the morecomplox the required mixed wasta disposal infrastmcturo.

c) Flexibility - the groatar tha flexibility of the metal shapingprocas~, the more likely tho procass will be abla to respond tonow mixed waste r~quiraments.

d) Haalth and Safety - tha primary concarn is to minimiso thepotantial radiation and chemical ●xposure of pnrsonnel involvedin tha mixed wasta disposal process.

●) costs - tho processing costs of mixed wast~ disposal areassumed to be directly relatad to th~ amount of mixed wasteganerated.

8

3. public Perception of Mixed Wasto Generation and DisposalProblem

Three Subcriteria each related to an ●spect of mixed wastedisposal:

a) Transportation - the travel route and its usage frequency fortransporting mixed waste from its generating source to its finaldeethation.

b) Ultimate DiSpOSal Destination - the location and container-ization method of the final burial site for generated mixedwamte.

c) Packaging - the ability of the tr~port contair :0 remainintact in case of an accident during tha mvement . .JiXOd wasteto its disposal destination.

Figure 2 displayo the hierarchical ordering of these

criteria as they relate to the overall goal of identifying the

metal shaping process that will produce tha minimal impact on

mixed wanta generation and disposal. w reducing a problem into

its ●lements and grouDing these ●lemants at different levels, a

hierarchy is formed. Weights reflecting the relative importance

of ●ach criteria (and mbcriteria) can then be assigned by

perfo-ng pai-ise comparison at ●ach level in the critaria

hierarchy. As previously mentioned, this NIP modeling stricture

is especially effectivo when a variety of different types of

crit~ria, some quantitative and some qualitative, must be

aggregated into an overall score to rank ●ach solution

alternative.

ste~ ~co Bstabliching Criteria/Subcriceria Weights:

.Aashown in Figure 2, the r~lativa importmca of the three

major criteria was determined. Public perception of the mixed

wasta problam was thouuht to ha four timas am Important as the

difficulty in disposing of the mixed wasta and over twice as

9

important as the actual amount of waste that is generated. Since

quantitative data were a~ailable on the costs associated with

disposing of an unit of each type of mixed waste, they were used

to determine the weights for the four different t~m of mixed

waste generated. In contrast, pairwise comparisons based on

qert judgments were used to determine the priorities

associated with each of the five subcritoria related to mixed

wasto disposal ~ !~iculty. Finally, the rolativo importance of

●ach of the three dimensions thought to h related to the

public’s perception of the mixed wasta problem was subjectively

●valuatmd by the analysts. The results of these evaluations are

shown in Figure 3.

flt@D3d. Ranking Alternative Solution Technologies Against the

Criteria/Subcriteria:

Numerical estimates are made of the amounts of mixed waste

that are ge.narated by aach of the compoting metal shaping

tocbnologies. Since less rather than more mixed waste is

prafarred, the inverso of these amounts was directly used to

ascartain the preference of ●ach technology ralative to each of

the four subcriteria under ‘Amount of Mixed Wast@ Generated”.

Again, expert judgement, though tho pairwisa comparison

tocbnique, was used to rank tho desirability of ●ach alternative

technology relative the five ‘Difficulty in Disposing of the

Mix-d Waste Generatedn subcriteria. It is interesting to note

that tho performance of the throo tochnologias was assoss~d as

●qual for the thrao ‘Public Parcoption” wbcriteria, that is, it

is ●ssumed tho public is indiffcrmt about which metal shaping

10

technology is used to ganerate mixed

synthesizing procedure indicate that

squally preferred:

Near

8inco the alternative

it 1s Lmportant to examine

Th9 pcmformance of each of

Wrought

Ne~:s~~e

Net Shape

wa8te . me results of the

tbe alternatives are about

Casting = .309

Canting = .331

Casting = .360.

technology scores aro relative clese,

EC’S built-in sensitivity analyses.

the altermativo tacbnologies is

graphically displayed in Figure 4. It is noteworthy that Net

8hape Casting achieves its ovarall profarencc through its higher

ranking in the first critsrion, Amount of Mixed Wasto (kneratod,

●ven though this criteria has only ● 0.25 waight.

S~Y AND CONCLUSIONS

If the T Lxad waste generation and disposal rnituationwas Lhe

only major p. ~lam, it would be appropriate to roco-nd that tho

Casting process be incorporated into a now procass flow

tho plutonium processing facility. Mfora implamanting

ramovo tho current mmtal shaping procass and install

Casting, howovar, it is nacossary to imitate fauility

parformauc ● with a modal. A computar-based dymamic simulation

modal will allow a t~st of tha mow procoss configuration under a

numbar of diffcrant operational configurations and material

flw8 . If tha ●mploymant of tha now -tal shaping prousss had

soma undaairablo ●ffocts on other maasuras of faaility

parfomanco, then tha bahavior of tha soaond ranhd prorass, Near

Nat Shapo Casting, would ba modalod

implamantation could ba data~inod.

11

befor, ● final daoision for

LIST O? FIGURE TITLES... . .

FIGURE 1 - A ~THODOLOQICAL APPROACH FOR ADDRESSING MAJOR

PROBLEMS IN A PLUTONIUM PROCESSING FACILI~

FIGURE 2 - CRITERIA/SUBCRITERIA HIERARCHY WITH ASSIGNED WEIGHTS

FIGURE 3 - SUBCRITERIA ORDERJYDWIN~ BY C-UTBD PRIORITIES

PIQURM 4 - RELATIVE AND O~L PBRPOWANCE OF ALTERNATIVE

TBCHNOLOQIEW

12

\ DESIRED FACILITY / I DETERMINE MAJOR MIXED I \ ACTUAL FACILITY /

LFiRFORMANCE WASTE PROBLEMS BYLEVELS FOR COMPARINO ACTUALWITH

MIXED WASTE DESIRED PERFORMANCE

rSET OF POTENTIAL SPECIFY WEIGHTS FORCRITERIA FOR RELEVANT CRITERIA AND

IDENTIFYIN(3 PRIORITIZE MAJOR PROBLEMSMIXED WASTE I USING Expert Chob PAIRWISE

\ PROBLEMS / I COMPARISON FEATURE

\

/

SET OF POTENTIALCRITERIA FOREVALUATING

\ NEW PROCESS~ECHNOLOGIES/

i

SELECT PROBLEMWITH HIOHEST

PRIORITY

m

SPECl~ WEIGHTS FORRELEVANTCRITERIA ANO

RANK THE PROBLEM SOLVINGPOTENTIAL OF TECHNOL~lESUSING ExportCholco PAIRWISE

COMPARISON FEATURE

~–

+!!!No

CREATE SET OF ALTERNATIVEFLOWSHEETS USING

COMBINATIONS OF HIGHLYRANKED TECHNOL~lES

CREATE AND OPERATE A SETOF ALTERNATIVE (LOWSHEETMODEL8 ● ANALYZE RESULTSFOR TECHNOL~Y INSIGHTS

E=iEiElINCORPORATE EFFECTIVE TECHNOLOGIES

SELECT METAL SHAPING PROCESS TO MINIMIZE Il@ACT OF MIXED WASTE

IGOAL1.000 I

I

t I I

nGEN0.250

II

I

I I I 1TDISP IF0.1s0

q

PUBP0.600

mmmm I “p’”mm00450

mm --- MOUNT 0? MIXED WASTE TO ~E 6=-TED / XO 3? METAL PRODUCEDMPLEXY “-- DISPOSAL COmLEXXTY - f (~ER 0? TYPM MIXED WASTE OENERATED)MT8 --- ASSUME DISPOSAL COSTS ARE DIRECTLY RELATED MIXED WASTE MT OENMPDIFF --- DIFFICULTY IN DISPOSINGOF ICIXEDWASTEXXIBLY --- FLEXIBILITY0? CMTINO PROCESS TO MEET lfEUMIXED WASTE UOUMTIONSXH8A?E --- ABILITY 0? MIXED WA8TS DISPO$AL PROCESS TO MIN. UOm EXPOSUREi-LIQ --- LOW UVEL MIXED LIQUID WASTE (LT] ~~mTED / METAL PRODUCED (XO)+SOLXD --- UW XJVEL SOLID MIXED WMTE (KG) a~_TED / ~AL ●RODUCED (X@)ISCMT --- HEAR NET SHAPE CASTZNGICMT =-- Mm $XAPB CASTINGKRMt --- PAa6E OR CONTAINERUSED TO TRMMPORT MIXED UA8TEJBPERCP --- ~LIC ?ERCZPTION0? NIXED WASTE GENERATION AND DI#’O$AL PROBL~~mn ‘“- DEGME 0? COMFID~CE IN ESTIXATES 0? MIXZD WASTE a~mT~D MOUNTlA#IJSPRT--- TRANSPORTATION COMC~S--ROUTS AND TRUCK USAOS FREQUENCYKbLIQ --- TRU NIXED LIQUID WASTE (LT) OmmTm / ~~ p~oDucrD (x~)IU-SOLI--- TM SOLID MIXED WASTE (KC) OENWTED / METAL ?RODUCED (RO),T-DISP--- ULTIMATE DISPOSAL (BURIAL) SITE WCATIONtOUGJIT--- UROUGNT CASTINO

LernAlamo- National Laboratory

SELECT METAL SHAPING PROCESS TO MINIMIZE IHPACT OF MIXED WASTE

Sortod Synthasis of Imml 2 Nodas with raspoct to GOAL

OVERALL INCONSISTENCY INDEX = 0.00

ANSPRT 0.270

CKAGE 0.270

U-SOLI 0.140

U-LIQ 0.065 ~

T-DISP 0.060 ~

STS 0.052 ~

-LIQ O.oas ~

-SOLID 0.017 ~

EXIBLY 0.012 -

KPLEXY 0.008 _

-TY 0.007 =

1 ● 000

HPLEXY --- DISPOSAL CO~LEXITY = f (NUKBER OF TYPES MIXED WASTE GENERATED)6TS --- ASSUMEDISPOS(RLCOSTS ARE DIRE~LY RELATED MIXED WASTE MT GENEXIBLY ‘-- FLEXZBILTYOF CASTING PROCESS TO MEET NEW NIXED WASTE REGULATIONSrNsArE -“- ABILITY OF MIXED WASTE DISPOSAL PROCESS TO MIN. WORKER EXPOSURE-LIQ --- LOW LEVEL MIXED LIQUID WASTE (LT) GENERATED / METAL PRODUCED (KG)-SOLID --- MW LEVEL SOLID MIXED WASTE (KG) GENERATED / METAL PRODUCED (KG)CKAGE --- PACKME OR CONTAINER USED TO TRANSPORTMIXED WASTECWSATY --- DEGREE OF CONFIDENCE IN ESTIMATESOF MIXED WASTE GENERATED AMOUNTMSPRT --- TRANSPORTATIONCONCERNS--ROUTE AND TRUCK USAGE PREQUENCYU-LIQ --- TRU KIXED LIQUID WASTE (LT) GENERATED / METAL PRODUCED (KG)U-SOLI --- TRU SOLID MIXED WASTE (KG) GENERATED / METAL PRODUCED (M)r-DZ8P --- ULTIMATE WASTE DISPOSAL SITE MCATION & CONTAINERIZATIONMETHOD

Rltx50

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30

20

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