In a demonstration of its largest domestic program to reduce stocks of weaponizable nuclear material, the National Nuclear Security Administration in December shipped deweaponized plutonium out of South Carolina for permanent disposal, the agency said recently.
It was a proof-of-concept run for the Surplus Plutonium Disposition Program, which began as a post-Cold-War plowshares effort with Russia and afterward morphed into a big legal dispute with one of the agency’s (NNSA) most important host states.
The National Nuclear Security Administration (NNSA) did not say how much plutonium it removed in December from the Savannah River Site near Aiken, S.C., though a spokesperson said Friday in an email that each shipment from the site “can contain up to 16 kilograms of downblended plutonium.”
The plutonium, in oxide form before Savannah River workers blended it with concrete-like grout and sealed it up at the site’s K-Area, came from two separate tranches, the spokesperson said: one about 6 metric tons in mass, the other 7.1 metric tons. The government this plutonium surplus to national defense needs after the Cold War. Neither tranche included plutonium pits, the fissile cores of nuclear-weapon first stages, NNSA has said, though the agency had previously considered how to dispose of a separate tranche containing 7.1 tons of surplus pit plutonium.
The NNSA is building its own three-glovebox facility at K-Area to handle the bulk of Savannah River’s contribution to the Surplus Plutonium Disposition Program, also known as dilute dispose, but the facility will not be done until March 2026 at the earliest or March 2028 at the latest, the NNSA spokesperson said Friday.
For now, the NNSA dilutes and disposes of plutonium by paying for time and labor at an existing K-Area glovebox owned by the Department of Energy’s Office of Environmental Management, which has its own plutonium-disposal mission at the site.
December’s shipment from Savannah River “marks a milestone as the first shipment to include defense TRU [transuanic waste] material from NNSA’s Surplus Plutonium Disposition Program,” the NNSA wrote in a Jan. 13 press release. “After plutonium is downblended at SRS [Savannah River Site], it becomes TRU material by definition and can be permanently disposed at” the Waste Isolation Pilot Plant in New Mexico.
The Surplus Plutonium Disposition Program is NNSA’s replacement for the Savannah River Site’s canceled Mixed Oxide Fuel Fabrication Facility. Altogether under the new program, the government planned to dispose of 34 metric tons of plutonium by processing it at the Los Alamos National Laboratory in northern New Mexico, blending it down it at Savannah River and burying it at the Waste Isolation Pilot Plant near Carlsbad, N.M.
In 2020, the federal government and the state of South Carolina settled a long-running lawsuit over the NNSA’s failure to begin removing this weapon-usable plutonium from South Carolina by a legal deadline of 2016. By that time, the Mixed Oxide Fuel Fabrication Facility’s proposed mission, to create fuel for nuclear power plants, had become commercially untenable. The NNSA moved to pull the plug, but legislative gridlock kept that from happening for another two years.
All the while, South Carolina, taking advantage of a federal law Sen. Lindsay Graham (R-S.C.) helped write, was tallying fines for the NNSA for failing to get the mixed oxide mission going.
But months before the 2020 presidential election, there was a break in the lawsuit, as the government decided to settle. South Carolina got a state-record $600 million from the Department of Justice’s Judgement Fund — not the Department of Energy’s budget — and agreed to give the agency until 2037 to remove 9.5 tons of surplus plutonium from the state by 2037.
If the NNSA misses that deadline, the government will have to pay South Carolina $1.5 billion more, according to the terms of the settlement.
That bought the NNSA time to ramp up the Surplus Plutonium Disposition Program and to begin converting the Mixed Oxide Fuel Fabrication Facility into the Savannah River Plutonium Processing Facility, which the agency last year estimated will begin making nuclear-weapon cores by 2036 and which South Carolina hopes will make up for lost jobs at the mixed oxide program.