Because of sharply rising cost estimates for plutonium disposition facilities under construction in South Carolina, the Obama Administration proposed in its FY2017 budget request to end construction and pursue a "dilute and dispose" (D&D) option. The Trump Administration proposed the same strategy in its FY2018 budget request. In September 1998, the United States and Russia each agreed to convert 34 metric tons of surplus weapons-grade plutonium to a form that could not be returned to nuclear weapons under the Plutonium Management and Disposition Agreement (PMDA). The two countries agreed to begin plutonium disposition in 2018. The plutonium disposition program, including U.S. assistance for the Russian program, is administered by the National Nuclear Security Administration (NNSA), a semiautonomous agency of the Department of Energy (DOE). A key component of the U.S. strategy for disposing of surplus weapons plutonium has been the Mixed Oxide Fuel Fabrication Facility (MFFF) at DOE's Savannah River Site in South Carolina. NNSA estimated in 2002 that MFFF would cost about $1 billion to design and build. According to DOE's FY2014 budget request, the MFFF contractor then estimated that the project's total construction cost would rise to $7.78 billion, and that construction would not be completed until November 2019. 113-235 ) each required DOE to conduct independent cost and schedule estimates for MFFF and analyze alternative disposition approaches. "As a result, beginning in FY 2017 the MFFF project will be terminated." In its FY2018 request to Congress, the Trump Administration supported the proposal to "terminate the MOX project and pursue the dilute and dispose strategy as an alternative." The current poor political climate between the United States and Russia was another factor to consider. Russian Program

Russia promised after suspending its participation in the PMDA not to use its 34 metric tons of surplus plutonium for weapons. The FY2013 budget justification said that the requested funds would be used to "provide technical support to the DOE in meeting U.S. obligations to support disposition of weapon-grade plutonium in Russia; provide U.S. technical oversight of work in Russia associated with the disposition of surplus Russian weapon-grade plutonium in the BN-600 and BN-800 fast reactors; and support the implementation of IAEA verification activities in both the U.S. and Russia." The FY2014-FY2018 budget requests included no funds for the Russian plutonium disposition program. The program had long planned to blend surplus plutonium from the U.S. nuclear weapons program with uranium to make MOX fuel for commercial nuclear reactors. After fueling a reactor for several years, the plutonium in MOX fuel would be mostly destroyed by fission, and remaining plutonium would be isotopically less desirable for weapons use. In addition, the used MOX fuel would contain highly radioactive fission products that would provide an obstacle to diversion for weapons purposes. DOE's FY2015 budget justification said the total lifecycle cost of the MOX disposition option had risen to $30 billion—from $24.2 billion in April 2013. However, Congress rejected the Administration's plan to put MFFF in "cold standby." Instead, Congress appropriated $345 million to continue MFFF construction at a reduced level from FY2014 and required DOE within 120 days to conduct an "independently verified lifecycle cost estimate for the option to complete construction and operate the MOX facility and the option to downblend and dispose of the material in a repository." DOE requested $345 million for FY2016 to continue MFFF construction at the FY2015 level, pending a decision based on the new study.
The Mixed Oxide Fuel Fabrication Facility (MFFF) in South Carolina has been a key component of the current U.S. strategy for disposing of surplus weapons plutonium from the Cold War. Disposition of surplus plutonium is required by a 1998 agreement, amended in 2010, between the United States and the Russian Federation. Each country agreed to convert 34 metric tons of surplus weapons-grade plutonium to a form that could not be returned to nuclear weapons, to begin in 2018. Russia suspended its participation in the agreement in October 2016 due to what it called "hostile actions" by the United States. However, both countries appear to be continuing their plans for surplus plutonium disposition.
The U.S. disposition strategy called for the surplus plutonium, in oxide form, to be blended with uranium oxide to make mixed oxide (MOX) fuel for U.S. commercial nuclear reactors. The plutonium in MOX fuel would be mostly destroyed in the reactors by fission (splitting into other isotopes). At the same time, isotopes of plutonium undesirable for weapons would be created, along with highly radioactive fission products. As a result, after several years in a reactor, spent MOX fuel would have less total plutonium than when it was freshly loaded, and the remaining plutonium would be degraded for weapons purposes. Moreover, the fission products would make the material difficult to handle, in case of future attempts to use the plutonium.
Because of sharply rising cost estimates for the MOX project, the Obama Administration proposed to terminate the project in its FY2017 budget request. The Trump Administration in its FY2018 request also proposed replacing the MFF with the dilute and dispose option. Starting with the FY2015 budget request, the Administration proposed placing MFFF in "cold standby" and studying other plutonium disposition options. However, Congress authorized and appropriated $345 million for FY2015 to continue construction at a reduced level and required the Department of Energy (DOE) to procure an independent cost and schedule estimate for MFFF and alternative disposition approaches. Pending the results of those analyses, DOE requested $340 million for FY2016 to continue construction at about the FY2015 level. DOE's FY2017 budget proposed to instead pursue a dilute and dispose (D&D) program.
The federal plutonium disposition program is run by the National Nuclear Security Administration (NNSA), a semiautonomous agency of DOE. NNSA estimated in 2002 that MFFF would cost about $1 billion to design and build. DOE said in its budget justification for FY2014 that the MFFF contractor had estimated the project's total construction cost would rise to $7.78 billion, and that construction would not be completed until November 2019. DOE's FY2015 budget justification said the life-cycle cost estimate for the MOX program had risen to $30 billion.
Differing sharply from the U.S. MOX strategy, Russia is planning to use its BN-600 and BN-800 fast breeder reactors for plutonium disposition. According to the World Nuclear Association, the BN-800 started producing electricity in 2015, and the reactor is "capable of burning 1.7 metric tons of plutonium per year from dismantled weapons." The DOE FY2015 through FY2018 budget requests included no funds for support of the Russian plutonium disposition program.
The debate over U.S. plutonium disposition strategy raises several issues for Congress. The Administration asserts that the rising cost estimates for MFFF are unsustainable in the current budget environment and proposes a different disposal method. The effects of alternative disposal options on DOE's Savannah River Site in South Carolina, where MFFF is located, will also be an important element of the debate.