The National Nuclear Security Administration’s plan to produce 80 pits a year would generate more than 1,110 cubic meters of transuranic waste a year, according to an environmental review the semiautonomous Department of Energy weapon steward released this week.
Over 50 years — enough time at an 80-a-year throughput to produce two new pits, and then some, for each of the 1,550 U.S. nuclear weapons deployed under the New START treaty — that would create enough transuranic waste to fill more than 50% “of the projected available capacity” at the Waste Isolation Pilot Plant (WIPP), according to a National Nuclear Security Administration’s (NNSA) final supplement analysis, published officially on Tuesday.
In NNSA’s final supplement analysis — a necessary environmental hurdle to clear before embarking on now-funded plans to build new pit plants at the Los Alamos National Laboratory and the Savannah River Site — the agency said it foresees no problem getting transuranic, or TRU, waste from the pit program into WIPP.
“A large emphasis is placed on meeting NNSA shipping requirements to support active projects and missions related to national security and stockpile stewardship,” the NNSA wrote in the supplement analysis. If the NNSA mission produces more TRU waste than expected, DOE’s National TRU Program “would evaluate other priorities in the complex to compensate.”
Pits are the fissile cores of nuclear weapons. Transuranic waste refers to items and substances contaminated by elements heavier than uranium, typically plutonium. WIPP is the only deep-underground repository for transuranic waste.
The NNSA’s 50-year estimate of TRU waste production from pits is, at this point, useful mostly for scale; WIPP is not authorized by federal law to operate for 50 years beyond the projected 2030 start of the NNSA’s pit mission.
WIPP is, however, authorized to hold a total of roughly 175,000 cubic meters worth of waste, under the Land Withdrawal Act that allowed DOE to mine the repository out of a permian salt basin near Carlsbad, N.M.
WIPP closed for about three years after an underground radiation leak in 2014, but the mine has otherwise been filling up with shipments since 1999. After changes in 2018 to the way DOE accounts for the volume of buried waste at WIPP, the agency estimates the mine has just under 110,000 cubic meters of usable space left. Congress authorized the mine to hold some 175,000 cubic meters of waste.
Two advocacy groups have challenged New Mexico’s 2018 decision allowing DOE to change how it accounts for waste volume underground at WIPP. The tweak sliced the accounted volume of waste already stored in the mine by about 30%.
WIPP primarily contains waste from shuttered, Cold War-era nuclear weapons production sites. After the NNSA’s pit mission comes online, the TRU waste streams from those sites will compete compete for underground space with the NNSA’s anticipated stream.
WIPP potentially faces a capacity crunch. All the waste potentially bound for the mine could take up more than 190,000 cubic meters, Todd Shrader, now the second in command at DOE’s Office of Environmental Management, said in June 2018.
Congress and the President would have to change existing law to raise the volume cap on WIPP waste.
Editor’s note: This article has been updated to clarify the timing of comments from Todd Shrader.
