The Department of Energy should take a number of steps to ensure it comprehensively understands its transuranic waste management needs as it looks to dispose of 34 metric tons of diluted plutonium at its Waste Isolation Pilot Plant (WIPP) in New Mexico, the Government Accountability Office said in a report Tuesday.
WIPP is the nation’s sole permanent underground disposal site for waste contaminated by nuclear elements heavier than uranium, such as plutonium, from across the DOE complex. It reopened in December after a nearly three-year shutdown following an underground fire and subsequent, unrelated radiation release.
The Energy Department anticipates filling WIPP to its current capacity by 2026, requiring further excavation in the underground mine, which currently lacks the room for disposal of all U.S. defense transuranic waste.
“While DOE officials recognize that expansion of WIPP’s disposal space may be necessary in the future, they have not analyzed or planned for the facility’s expansion because their focus has been on resuming operations at WIPP,” congressional auditors said. The report notes that DOE’s existing five-year transuranic waste management plan does not address WIPP expansion; the agency is also not expected until 2024 to complete modeling that would be needed for what is likely to be a years-long regulatory review of expanding WIPP.
The challenges facing WIPP are emphasized by DOE’s plan to scrap the Mixed Oxide (MOX) Fuel Fabrication Facility at the Savannah River Site in South Carolina in favor of a “dilute and dispose” method in which processed plutonium would be sent to WIPP rather than converted into nuclear reactor fuel, GAO said.
The surplus plutonium is to be eliminated under the terms of a 2000 U.S.-Russian deal, which Moscow stepped back from last year. The Energy Department has spent $5 billion to date on the MOX project, but both the Obama and Trump administrations have determined it would be far cheaper and faster to abandon the project in favor of downblending and storage. The GAO said DOE had applied best practices to its updated $17.2 billion estimate to finishing the conversion plant, but not yet to the $51.3 billion life-cycle estimate for MOX plutonium disposition.
The department’s 2016 transuranic waste inventory encompasses 68,350 cubic meters of contact-handled waste and 3,160 cubic meters of remote-handled waste to be buried at WIPP – which does not cover any part of the 34 metric tons of plutonium.
Specifically, congressional auditors said, WIPP already stores 91.100 cubic meters of waste by volume of its current statutory capacity of 175,565 cubic meters. Accounting for waste that is already due or possible to be shipped, it would reach that capacity even without the surplus plutonium.
To address these issues, GAO said, the Energy Department should develop a long-term plan for disposal of transuranic waste and a schedule for determining whether “potential” transuranic waste can be shipped to WIPP, among other measures.
The Energy Department concurred with the recommendations, and plans to take a number of steps to address them, GAO said. These include issuing new directions by December 2018 “to assist DOE sites produce more comprehensive estimates of future TRU waste that may be generated from cleanup operations; and developing a long-term plan by December 2018 for disposal of DOE’s TRU waste.”
Todd Shrader, manager of DOE’s Carlsbad Field Office, on Wednesday acknowledged the potential for additional plutonium to be shipped to WIPP. He noted that the facility is already home to more than 5 metric tons of plutonium in different forms shipped in prior years.
The Energy Department’s semiautonomous National Nuclear Security Administration in 2016 also authorized downblending and transport to WIPP of a separate tranche of 6 metric tons of non-pit plutonium now stored at the Savannah River Site.
“If a decision is made to downblend that plutonium, as it is shipped to WIPP … it would be in the form of transuranic waste,” Shrader said during the ExchangeMonitor’s RadWaste Summit in Summerlin, Nev.
Upgrades would be necessary at both Savannah River and WIPP to carry out the dilute and dispose plan, which would be funded by the Plutonium Disposition Program, according to the GAO report. That would include beefing up security at WIPP’s above-ground storage facility. “NNSA officials told us they do not have a current estimate of the costs for the upgrades at WIPP and have suspended the work assessing the costs for disposing of the plutonium at WIPP due to budget constraints.”
