AIKEN, S.C. (AP) -- Energy Secretary Rick Perry has formally ended construction of a facility meant to reprocess weapons-grade plutonium and uranium into fuel for reactors, a key element of the nation's commitment to containing the global nuclear threat.
Perry executed a waiver on Thursday to terminate construction of the Mixed Oxide Fuel Fabrication Facility at the Savannah River Site in South Carolina.
A day earlier, Perry called it a "historically questionable" expenditure in testimony before Congress about the Trump administration's 2019 budget proposal, which includes $220 million toward closing the project, and $59 million toward replacing it with a so-called "dilute and dispose" approach to surplus nuclear material.
The MOX was initially slated to open in 2016, blending weapons-grade plutonium and uranium into commercial reactor fuel. But its estimated construction cost soared from $1.4 billion in 2004 to more than $17 billion. About $5 billion had already been spent by last year, with completion not expected until 2048.
The MOX was proposed as part of the US-Russia nuclear non-proliferation agreement in 2000. Since then, the idea of converting potential weapons into safe energy has helped persuade leaders in multiple countries to surrender their nuclear material before it could fall into dangerous hands.
With MOX being discontinued, the National Nuclear Security Administration has proposed installing pits to store plutonium waste -- 50 per year at the Savannah River Site, and 30 per year at the Los Alamos National Laboratory in New Mexico.
A news release from NNSA said the two-pronged approach involving the pits "is the best way to manage the cost, schedule, and risk of such a vital undertaking."
Rep. Rick Allen, a Republican from Georgia, criticized the move on Friday, saying he still believes "MOX is the most viable way forward to dispose of our weapons grade plutonium," but he also supports installing pits at the Savannah River Site, which will continue to provide jobs in the local economy.
South Carolina Gov. Henry McMaster called dilute-and-dispose "not logical" during a March question-and-answer session in North Augusta.
"The Department of Energy has been trying to shut down the MOX project for years, breaking a promise to the people of South Carolina and breaking federal law along the way," McMaster said. "We will not accept it, and we will fight every step of the way to make sure South Carolina's interests are protected."
Several studies are needed and environmental concerns are to be addressed before dilute-and-dispose can fully proceed, according to a U.S. Environmental Protection Agency letter sent on April 2. The EPA said agency involvement in the matter at this point would be "premature."