Robert B. Hayes, Ph.D., CHP, PEAssociate Professor Department of Nuclear EngineeringNorth Carolina State University

NE 531/431, Fall 2019Nuclear Waste Management

Special thanks to Dr. Steven E. Skutnik, Department of Nuclear Engineering, UTK& Dr. Man-Sung Yim KAIST, S. Korea for assistance in providing draft course slides

NE 531 Hayes Lec. 17-2

What about the waste problem?

A football field with waste stacked up around 16 m is 80,000 m3

https://www.eia.gov/todayinenergy/detail.php?id=24052

NE 531 Hayes Lec. 17-2

https://www.eia.gov/todayinenergy/detail.php?id=24052

The (brief) history of U.S. spent fuel reprocessing

NE 531 Hayes Lec. 17-2

• Early development of nuclear technology was a war-driven effort

• Biological effects not yet fully understood

• Waste disposal driven by:– Economics– Security– Efficiency

Origins of waste management

Image: ORNL

NE 531 Hayes Lec. 17-2

PresenterPresentation NotesWaste management at best an afterthought; by and large, waste was stored in tanks and drums and buried. Problems emerge when these tanks begin to leak.�Much of waste management driven by security – shallow land burial gave some moderate amount of shielding, and it was understood soil could retard some movement of radionuclides. Much of the concern was to provide quick solutions which were cheap and did not require moving waste off-site (security concern).�

• AEC tasked with commercializing nuclear technology in light of Eisenhower’s “Atoms for Peace” program

• Push to rapid commercial deployment of reactor technology – Waste issue assumed to be technically resolved– Actual disposition of spent fuel left unresolved– Working assumption: All commercial spent fuel

will be reprocessed

Early working assumptionsNE 531 Hayes Lec. 17-2

PresenterPresentation NotesPriority in AEC days was in getting nuclear technology deployed / commercializedIt was always assumed, given the existence and knowledge of reprocessing technology, that spent fuel would simply be reprocessedTHIS ASSUMPTION IS VITALLY IMPORTANT!Reactors were designed with this assumption in mind (storage for 1-2 core offloads only)

• Basic technology for recovery of U and Pu well-understood– PUREX process

• 1966: AEC licenses Nuclear Fuel Services to operate a reprocessing plant for spent commercial fuel at West Valley, NY

Early reprocessing: West ValleyNE 531 Hayes Lec. 17-2

PresenterPresentation NotesWest Valley was the first commercial reprocessing plant in the U.S.“First-generation” technology – basic PUREX process

• Separation capacity: 300 MT/year• Initially designed to process spent fuel from

civilian reactors, however supply was insufficient– Too few deployed reactors

• As a result, military fuel was processed– Military fuel would compose 60% of the facility input – Most of the fuel was from the Hanford

N-reactor

West Valley: 1966-1971NE 531 Hayes Lec. 17-2

PresenterPresentation NotesSupply of fuel was not sufficient to meet demand for West Valley; military fuel was processed from Hanford to meet demandThis would cause problems.

• Extensive problems with site contamination– Poorly-understood lanthanide chemistry– Unacceptable worker exposures– Water infiltration of on-site landfill

• 1972: West Valley closes for renovations– Augment processing capacity– Reduce worker doses– Reduce radioactive effluent discharges

West Valley: Problems emergeNE 531 Hayes Lec. 17-2

PresenterPresentation NotesVery significant contamination issues owing to poorly-understood lanthanide chemistry. Ruthenium liked to travel with water – obvious problems here.Unacceptable levels of worker exposure due to this and other factors; water infiltration into on-site landfill lead to widespread contamination

1972: West Valley was shut down for renovations, including boosting process capacity and reducing rad effluents (to reduce worker doses)

• Initial renovation cost estimate: $36 million

• New, retroactive requirements imposed for upgrade:– Waste solidification required– New earthquake and tornado requirements– Cost estimate escalates to $600 million

• West Valley abandoned as a result– Legacy wastes (and contamination) left behind

The money pitNE 531 Hayes Lec. 17-2

PresenterPresentation Notes600,000 gallons of liquid wastes left in long-term underground storage containersExtensive site contamination

West Valley might be considered a regulatory failure – ex post facto rulemaking made it financially impossible to reopen. Technical lesson as well – “shaking out the bugs” in reprocessing at the commercial scale

• Built by GE in Morris, IL– Construction completed mid-1971– Capacity: 300 MT/year– Cost: $63 million

• Declared inoperable as-built in 1974– Never operated– Based on a laboratory-scale process (Aquafluor)

never brought to industrial scale– Currently used for SNF storage

Midwest Fuel Recovery Plant (MFRP)NE 531 Hayes Lec. 17-2

PresenterPresentation NotesMidwest Fuel Recovery Plant was an example of a technical failure – trying to bring on a lab-scale process up to industrial scale

MFRP never reprocessed any fuel; it currently still stores the fuel it was contracted to reprocess

• Designed to minimize production of radioactive effluents– Minimized use of solvent extraction stages– Only one solvent extraction stage employed

• Numerous equipment failures in scaling laboratory process up to industrial scale– Process determined to require a second solvent

extraction stage– Time required to complete: 4 years

Why did MFRP fail?NE 531 Hayes Lec. 17-2

PresenterPresentation NotesGoal of Aquafluor process was to eliminate as much as possible the need for solvent extraction stages; Aquafluor had only one.

Yet at the industrial scale, it was quickly realized an expensive retrofit for a second solv. Extr. Stage would be needed.

• 1970: Allied General Nuclear Services begins construction of Barnwell Nuclear Fuel Plant in Barnwell, SC

• Designed to be an advanced separations facility– First large-scale commercial reprocessing plant– Using latest PUREX technology

• Scheduled to operate in 1974– Delayed until 1977

Reprocessing at Barnwell, SCNE 531 Hayes Lec. 17-2

PresenterPresentation NotesBarnwell was a “state of the art” reprocessing facility – would have been the largest in the world, and large even by modern standards

• Waste solidification– Conversion of liquid uranium into UF6 – Conversion of liquid plutonium into PuO2– Waste solidification of liquid HLW for shipment

to a HLW repository• No liquid effluents

• High capacity: 1500 MT/year

Technical features of BarnwellNE 531 Hayes Lec. 17-2

PresenterPresentation NotesBarnwell designed to solidify (vitrify) HLW so no liquid effluents leave the plant, eliminating problems seen at West Valley and other places

Recovered materials converted into an immediately useful form – UF6 for re-enrich, and PuO2 for MOX fuel

• 1976: President Ford “temporarily” suspends domestic reprocessing over nonproliferation concerns

• 1977: Executive order by President Carter:– “We will defer indefinitely the commercial

reprocessing and recycling of plutonium produced in the U.S. nuclear power programs”

• $500-700 million had already been committed to the Barnwell facility

1976-1977: Politics happensNE 531 Hayes Lec. 17-2

PresenterPresentation NotesBarnwell, as it were, was a victim of politics – specifically, the politics of nonproliferation

• 1981: President Reagan lifts the ban– “I am lifting the indefinite ban which previous

administrations placed on commercial reprocessing activities in the United States…”

• Damage had already been done– AGNS abandons efforts to pursue reprocessing at

Barnwell– Given political uncertainty and other factors,

commercial spent fuel reprocessing viewed as uneconomical

Aftermath of the Carter OrderNE 531 Hayes Lec. 17-2

PresenterPresentation NotesReagan lifted the ban, but pulled the plug on any further subsidies for the Barnwell plant. This, combined with the extensive politically-imposed outage and uncertainty, essentially killed the commercial reprocessing industry

• No commercial interest in the U.S.• Current legal regime moots private incentives

for reprocessing– Federal government “owns” spent fuel– Operators pay for disposal

Current status of reprocessingNE 531 Hayes Lec. 17-2

PresenterPresentation NotesNo current interest in reprocessing – due both to high capital cost and lack of incentives, given the Nuclear Waste Policy Act

Disposal is “paid up front,” meaning no one has an incentive to pay to reprocess spent fuel. Especially given that reprocessing costs more than storage and MOX costs more than fresh UO2 fuel.

• Reprocessing ongoing in many countries with nuclear fuel cycles, including:– France

• 1700 MTU/year capacity (PUREX)– Japan

• 800 MTU/year capacity (COEX)– U.K.

• 900 MTU / year capacity (PUREX) – Russia

• 2 plants; ~1900 MTU/year capacity (PUREX / Pyroprocessing)– South Korea

• Ongoing research and interest (Pyroprocessing)

Effect of Carter order abroadNE 531 Hayes Lec. 17-2

PresenterPresentation NotesSo… did the Carter order discourage reprocessing technology? Not really.

Geologic disposal in the U.S.

NE 531 Hayes Lec. 17-2

• Even with reprocessing, a geologic repository is still required for disposal of high-level wastes

• The process of developing a suitable HLW repository has been ongoing since the 1950s

OverviewNE 531 Hayes Lec. 17-2

• Main Pu production facility for the Manhattan Project– Hanford B-reactor

• Pu production reactor during theCold War– Hanford N reactor– Generated 57 tons

of Pu for weapons

Hanford reservation

Image: Wikipedia

NE 531 Hayes Lec. 17-2

• 2/3 of U.S. HLW (by volume) at Hanford– 200,000 m3 liquid waste– 710,000 m3 solid waste

• 92% from weapons-related activities

HLW at HanfordNE 531 Hayes Lec. 17-2

• HLW from reprocessing stored in underground tanks– 149 single-shell tanks, 28 double-shell

HLW storage at Hanford

1973• 15 single-shell

tanks discovered to be leaking

1989• 4 sites at

Hanford listed as EPA “Superfund” sites

1995• 67 single-shell

tanks known or suspected to be leaking

NE 531 Hayes Lec. 17-2

• Most of liquid waste has been transferred from single-shelled tanks– “Sludge” remains

• “Sludge” and salt cake formed from the varied, caustic chemicals in tanks– “Layer” chemistry– Removal & treatment of

“sludge” an ongoing challenge

Hanford “sludge”

Image: Wikipedia

NE 531 Hayes Lec. 17-2

• Experiment to determine the suitability of storing HLW from spent fuel in salt formations

• Canisters containing spentfuel stored in the salt mine

• Goal: Evaluate radiological impact on salt formations

Project “Salt Vault”

Image: Power magazine

NE 531 Hayes Lec. 17-2

PresenterPresentation NotesAbandoned Carey Salt Company Mine – Lyons, KS

• Salt Vault project terminated in 1967– All spent fuel removed from the mine

• Useful insights obtained about salt dome repository performance– Salt properties unaffected by high radiation fields– AEC concluded salt bed formations suitable for HLW

& SNF storage

• Project enjoyed widespread community support

The success of “salt vault”NE 531 Hayes Lec. 17-2

• Project designed for waste to be completely removed upon experiment completion

Reversibility

• Community groups consulted before the project began

Local consent

• Regular tours of the facility open to the public• ORNL staff made efforts to conduct the experiment in the full

view of the public

Transparency

Why did “Salt Vault” succeed?NE 531 Hayes Lec. 17-2

• 1969: Major fire at the Rocky Flats plutonium pit facility– Large volumes of low-level, plutonium-

contaminated debris generated– Contaminated debris temporarily relocated to

Idaho Falls, ID

• AEC Chairman Seaborg commits to removal of all Rocky Flats waste from Idaho by 1980

Rocky Flats facility fireNE 531 Hayes Lec. 17-2

Salt formations considered

Image: “The Disposal of Radioactive Waste on Land,” NAS (1957)

NE 531 Hayes Lec. 17-2

PresenterPresentation NotesAEC concluded based on prior studies a salt dome formation would be most suitable for immediate HLW disposal

Two largest formations: Lyons, KS and Michigan

• 1970: AEC announces selection of Lyons, KS site for HLW disposal site, pending confirmatory tests– Immediate objection by Kansas officials– Little prior consultation or discussion

• 1971: Senate amendment forbids AEC from establishing a repository until an independent advisory board reports to Congress

Salt Vault, reduxNE 531 Hayes Lec. 17-2

PresenterPresentation Notes1971 Amendment put forth by Sens. Dole and Pearson of Kansas, forbid AEC from buying land or burying any waste materials until an independent commission, appointed by the president, signed off on the safety of establishing an underground repository at the Lyons site; essentially “handcuffing” AEC

Larger problem was the perception of political “arm-twisting” – Lyons site perceived to be chosen out of political expediency over a rigorous technical process for site selection

• Numerous unforeseen technical issues identified– Several oil and gas boreholes found to be impossible

to plug– Unexpected evidence of water infiltration

• Ardent local opposition– Project perceived as rushed, political arm-twisting; lack

of a consent-building process– Perception that site choice was based on political

convenience over technical robustness

Lyons Salt Vault abandonedNE 531 Hayes Lec. 17-2

• Salt bed in Carlsbad, NM considered as an alternative to Lyons, KS

1973

• Congress authorizes construction1979

• First TRU waste shipments arrive1999

Waste Isolation Pilot Plant (WIPP)

Image: National Academies (1957)

NE 531 Hayes Lec. 17-2

NE 531 Hayes Lec. 17-2

NE 531 Hayes Lec. 17-2

WIPP facility layoutNE 531 Hayes Lec. 17-2

PresenterPresentation NotesNearly a half-mile underground�Excavation of salt shafts; heat from TRU packages causes a slow, plastic deformation of the salt where walls “close in” on waste, permanently sealing it into the formation

• WIPP presented as an economic boon for local community

Receptive public

• NM Environmental Evaluation Group (EEG) established to provide independent scientific oversight of WIPP project

Independent oversight

• Only defense TRU waste• Not a “national dumping ground”

Limitations on scope

Why did WIPP succeed?NE 531 Hayes Lec. 17-2

• What were some of the most important differences between Lyons, KS (revisited) and WIPP?

DiscussionNE 531 Hayes Lec. 17-2

PresenterPresentation NotesWhat made WIPP succeed where Lyons failed? Why was Salt Vault successful the first time around and not the second?

• Hayes R. B. (2016) Consequence assessment of the WIPP radiological release from February 2014. Health Phys. 110(4), 342-360.

Research focusNE 531 Hayes Lec. 17-2

How was this possible?An overview of the history of the WIPP event leading to the release

NE 531 Hayes Lec. 17-2

Comedy of errors?

• LANL chemists instructed this material had to be neutralized with inorganic material only– Operations recorded this as material has to be neutralized with an organic material

only

• LANL violated their permit – Permit allowed only characterizing the waste

• Industrial hygienist notified management that he was concerned the mixtures could have safety problems and requested LANL chemists review the process– Management did not follow through with the requested review

• Glovebox operators notified management by asking if the mixture should be smoking as observed– Management ignored this final warning

NE 531 Hayes Lec. 17-2

Follow on emergency response and recovery phases

NE 531 Hayes Lec. 17-2

The underground CAM went into saturation (2E5 max)

NE 531 Hayes Lec. 17-2

Actual WIPP release path

860 Fans

700 Fans

700 Fan

If everything operated as designed, how did a release occur?

NE 531 Hayes Lec. 17-2

700

Fan

700 Fans

860 Fans

Actual WIPP release path

Slide Number 1What about the waste problem?The (brief) history of U.S. spent fuel reprocessingOrigins of waste managementEarly working assumptionsEarly reprocessing: West ValleyWest Valley: 1966-1971West Valley: Problems emergeThe money pitMidwest Fuel Recovery Plant (MFRP)Why did MFRP fail?Reprocessing at Barnwell, SCTechnical features of Barnwell1976-1977: Politics happensAftermath of the Carter OrderCurrent status of reprocessingEffect of Carter order abroadGeologic disposal in the U.S.OverviewHanford reservationHLW at HanfordHLW storage at HanfordHanford “sludge”Project “Salt Vault”The success of “salt vault”Why did “Salt Vault” succeed?Rocky Flats facility fireSalt formations consideredSalt Vault, reduxLyons Salt Vault abandonedWaste Isolation Pilot Plant (WIPP)Slide Number 32Slide Number 33WIPP facility layoutWhy did WIPP succeed?DiscussionResearch focusHow was this possible?��An overview of the history of the WIPP event leading to the release�Comedy of errors?Follow on emergency response and recovery phasesThe underground CAM went into saturation (2E5 max)If everything operated as designed, how did a release occur?Slide Number 43Hidden lessons learnedSlide Number 45Assay of the waste shaft