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Sodium-Bonded Spent Nuclear Fuel Discussion for the National Spent Nuclear Fuel Program Office of Nuclear Materials Disposition Meeting. Debbie Kula Office of Nuclear Materials Disposition April 15, 2009. Challenge.
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Sodium-Bonded Spent Nuclear Fuel Discussionfor theNational Spent Nuclear Fuel Program Office of Nuclear Materials Disposition Meeting Debbie Kula Office of Nuclear Materials Disposition April 15, 2009
Challenge • The Department is currently responsible for the safe and efficient management of ~57 MTHM of Na-bonded SNF: • EM: ~0.25 MTHM FFTF fuel (driver) 34 MTHM Fermi-1 fuel (blanket) • NE: ~22 MTHM fuel from the EBR-II (~20 MTHM blanket, ~2 MTHM driver) • NNSA: ~0.05 MTHM Na-bonded-debris-bed fuel capsules from SNL • All has been consolidated at INL
Challenge, continued • WASRD: national repository will only accept HLW and/or SNF that is not subject to regulation as hazardous waste under RCRA. • Na-bonded SNF contains metallic sodium and could be considered a characteristic reactive waste under RCRA. • Either remove the Na or demonstrate the amount present is not reactive and will not negatively impact the repository. • If no national repository, may need to assess impact of Na on long-term storage.
Historic documents: • September 2000 ROD for the Treatment & Management of Sodium-Bonded Spent Nuclear Fuel (DOE/EIS-0306) • Decision to use EMT (Electrometallurgical Treatment) to treat the EBR-II SNF and “miscellaneous small lots” of Na-bonded SNF (FFTF fuel and the SNL Na-bonded-debris-bed fuel capsules). • The Fermi-1 Na-bonded SNF will continue to be stored while alternative treatments are evaluated. If no alternative proves more cost effective, EMT remains an option.
Historic documents, continued • March 2006 Report to Congress • Preferred Alternative is to: • Process EBR-II blanket and driver by EMT • Direct dispose Fermi-1 blanket and FFTF if not RCRA regulated • Otherwise use MEDEC (Melt-Drain-Evaporate-Carbonate process) or alcohol wash for Fermi-1 blanket and EMT for FFTF
Historic documents, continued • 2007 INL Preferred Disposition Plan for Sodium-Bonded SNF • Recommends: • Treating the EBR-II driver and blanket and Na-bonded FFTF using EMT • Notes MEDEC for the EBR-II blanket does not offer any significant advantages • Fermi-1 fuel should be treated by MEDEC if it cannot be direct disposed
Current Activities • NE currently treating small amounts of EBR-II fuel by EMT under AFCI. • ARRA (American Recovery and Reinvestment Act) funds to move some of the EBR-II fuel from the 666 basin to MFC. No additional funding to treat this fuel. • The Na-bonded FFTF fuels at Hanford were shipped to MFC. Funding for treatment of this fuel is still uncertain. • The two fuels are similar in composition and form and could be processed together.
EM’s Objective • Determine optimum solution for management (storage/treatment/disposal) of Na-bonded SNF • Although there is a 2000 ROD and subsequent studies, there is no concrete, integrated plan for all the Department’s Na-bonded SNF • Need to assess what should be done with this fuel • Is 2000 ROD still the answer? • Continue EMT? Who pays for what? • Determine RCRA applicability to Fermi-1 blanket? • Other technologies? • Plan for potential long term storage?
Next steps • Convene working group to develop a concrete, integrated path forward • Short term (through this CY): • Analyze options and recommend near-term activities • Elevate issues to management for decision • Longer-term: • Develop appropriate strategies to support revised Departmental policy based on proposed Blue Ribbon Panel
Driver vs. Blanket • Driver fuel swells when irradiated. The metallic sodium enters the metallic fuel and becomes inseparable. Separation requires dissolution or melting. • Blanket fuel does not swell to the same degree so there is no inter-diffusion between fuel and cladding. Mechanical stripping is possible.
Treatment Technologies • EMT (aka Electrochemical Treatment) • Direct Disposal • Two steps: (1) demonstrate the amount present is not reactive and (2) demonstrate it will not negatively impact the repository. • MEDEC (Melt-Drain-Evaporate-Carbonate): • First developed in 1980’s to remove sodium from non-irradiated EBR-II fuel. • Uses a combination of heat and reduced pressure to melt and vaporize bonded sodium, removing it from the metal fuel. • MEDEC tests showed the process is viable. • Additional evaluations are needed to demonstrate the waste form would be acceptable in the repository.
Treatment Technologies, continued • Alcohol wash • Used by Rocketdyne in mid-80’s to remove sodium from 17 MTHM of spent EBR-II blanket fuel. • Fuel element cladding is cut to expose fuel slugs, which are then soaked twice in an alcohol bath containing 20% water. Alcohol wash is solidified as sodium carbonate and disposed as LLW. • Historic documents have suggested this technology is due further evaluation.
Other Treatment Technologies • GMODS (Glass Material Oxidation and Dissolution System): • Combine unprocessed Na-bonded SNF and lead-borate glass in a glass melter at very high temperature. The U and Pu in the SNF would be converted into oxides and dissolved in the glass. • Waste form is borosilicate glass and would contain uranium, the transuranic elements, the fission products and the Na. • Direct Plasma Arc Vitreous Ceramic Process • The Na-bonded SNF would be cut into small pieces, melted and oxidized in a rotating furnace containing molten ceramic materials at extremely high temperatures. A direct current plasma torch would supply the energy required
Other Treatment Technologies, continued • Both GMODS and Plasma Arc technologies dismissed because they were not as mature as EMT and would require new construction and large equipment, new hot cells.