United States to dispose of 6 MT of weapon-grade plutonium in the Waste Isolation Pilot Plant

Tom Clements, Savannah River Site Watch

The U.S. Department of Energy (DOE) has made an initial decision to prepare 6 metric tons of surplus plutonium to be disposed of as nuclear waste. The decision is of note as it comes at a time when the fate of plutonium fuel (MOX) project at the Savannah River Site is uncertain.

The plutonium, now stored at the DOE's Savannah River Site in South Carolina, is to be prepared "for eventual disposal at the Waste Isolation Pilot Plant (WIPP) in Carlsbad, New Mexico, a geologic repository for disposal of Transuranic (TRU) waste generated by atomic energy defense activities."

The decision, by DOE's National Nuclear Security Administration (NNSA), comes after a lengthy environmental review process that began in July 2010 to analyze "the potential environmental impacts for the disposition of 13.1 metric tons (14.4 tons) of surplus plutonium for which a disposition path is not assigned, including 7.1 metric tons (7.8 tons) of plutonium from pits that were declared excess to national defense needs and 6 metric tons (6.6 tons) of surplus non-pit plutonium."

On December 24, 2015, NNSA issued a notice in the Federal Register entitled "Preferred Alternative for Certain Quantities of Plutonium Evaluated in the Final Surplus Plutonium Disposition Supplemental Environmental Impact Statement" in which the decision was made to dispose of 6 MT of plutonium in WIPP. But it won't be final until DOE/NNSA issues a formal Record of Decision (ROD) no sooner than 30 days from the date of publication of the notice in the Federal Register. [UPDATE: The Record of Decision was published in the Federal Registry on 5 April 2016.]

In April 2015, DOE issued the Final Surplus Plutonium Disposition Supplemental Environmental Impact Statement (Final SPD Supplemental EIS, DOE/EIS-0283-S2). The document analyzed various disposition alternatives for the surplus plutonium, including via plutonium fuel (MOX) irradiation in the Sequoyah and Browns Ferry reactors owned by the Tennessee Valley Authority, via immobilization in high-level nuclear waste at SRS and via disposal in WIPP. No "Preferred Alternative" for plutonium disposition was chosen in that document.

In the Federal Register notice of December 24, it was affirmed that "DOE/NNSA has no Preferred Alternative for the disposition of the remaining 7.1 MT of surplus plutonium from pits, nor does it have a Preferred Alternative among the pathways analyzed for providing the capability to disassemble surplus pits and convert the plutonium from pits to a form suitable for disposition." Thus, DOE remains undecided on MOX use in reactors owned by TVA reactors (the only nuclear utility that has expressed interest in MOX use).

While DOE has made the announcement on sending 6 MT of plutonium to WIPP, many hurdles remain to carry out this decision once the ROD is issued. No funding has been appropriated by Congress for downblending the plutonium at SRS for disposal. SRS currently lacks adequate infrastructure to carry out the mission and would need more gloveboxes, likely to be placed in the K Area, for packaging the material mixed with a secret inert material (called "stardust") from which it DOE believes it would be difficult to recover the plutonium so that the safeguards can be terminated.

The WIPP facility remains closed after accidents in February 2014 and the schedule for its "recovery" and reopening is unclear. Additionally, the volume of TRU waste going into WIPP was established under the Land Withdrawal Act and the ability of the facility to handle a large volume of packaged plutonium needs further analysis. At this time, it is unknown what level of political opposition there may be in New Mexico to taking plutonium to WIPP, which already has received 4.5 MT of plutonium as waste. The first shipment of plutonium from SRS to WIPP took place in 2012.

Funding and construction problems continue to plague the mismanaged MOX project but its fate will not begin to be known until the DOE releases its Fiscal Year 2017 budget to Congress on February 1, 2016. If MOX faces termination, the 6 MT of plutonium now designated to go to WIPP could be dramatically increased to include a significant portion of the 49 MT of separated plutonium that so far has been declared surplus to U.S. defense needs beyond the 4.5 tons already in WIPP.