Three DOE offices manage 57.2 MT of plutonium declared surplus to defense needs. These offices—NNSA, EM, and DOE’s Office of Nuclear Energy (NE)—and their sites manage a variety of surplus plutonium in the form of pits, metal, oxide, spent nuclear fuel, and other reactor fuels, and they follow specific procedures to manage the plutonium safely and securely. NNSA manages over half of this surplus plutonium. According to NNSA, all three offices share the responsibility for final disposition of surplus plutonium. Figure 1 shows the amounts of surplus plutonium managed by the offices. Figure 2 shows the various forms of this surplus plutonium, including pits, non-pit metal, non-pit oxide, and spent nuclear fuel or other reactor fuels in the inventory, by DOE office. Since 1997, DOE’s surplus plutonium disposition strategies have changed in terms of the method of disposal and the location for disposal, according to DOE documents and officials. These disposition strategies have included immobilization, irradiation as MOX fuel, and dilution. In 1997, NNSA planned to immobilize surplus plutonium by encapsulating it in glass or ceramic materials but terminated its plans in 2002 due to budget constraints. In the mid-2000s, EM briefly considered vitrification, which is a form of immobilization using glass, but never developed a plan to implement it. NNSA planned to irradiate surplus plutonium as part of the MOX fuel strategy but terminated its plans in 2018 because of high costs. NNSA’s plans for irradiation of MOX fuel would also have required disposal of the spent nuclear fuel in a high-level waste repository. EM began implementing a dilute and dispose strategy for a separate portion of surplus plutonium in 2012, but suspended its efforts until it resumed them in 2016. NNSA’s 2018 conceptual plan for the dilute and dispose strategy would replace the MOX fuel strategy with final disposal of the diluted plutonium at WIPP. Figure 3 shows a timeline of the changes in DOE’s strategies since 1997, as well as some key events that have affected the strategies. See appendix II for a timeline of DOE’s disposition strategies and appendix III for a timeline of key events concerning DOE’s Surplus Plutonium Disposition Program. Even if NNSA and EM had successfully implemented strategies for immobilization, vitrification, or irradiation of MOX fuel, DOE would have had no place to dispose of the surplus plutonium that was prepared for disposal because it planned to dispose of this material in a high-level waste repository, and no high-level waste repository has yet been constructed. WIPP would not have been able to take surplus plutonium from these disposition strategies because federal law authorizing disposal of radioactive waste at WIPP specifically bans the disposal of high-level waste and spent nuclear fuel, and the final forms of the surplus plutonium from these disposition strategies would have included both. DOE’s plans for a high-level waste repository have also changed over time. No progress toward licensing and building a high-level waste repository has been made since DOE terminated its licensing efforts in 2010. A high- level waste repository is likely still decades away from becoming operational. Appendix IV contains more information on the progress DOE has made toward licensing and building a high-level waste repository. NNSA’s current dilute and dispose strategy requires that surplus pits, as well as other surplus plutonium in metal form, be converted to plutonium oxide. NNSA’s now-terminated strategy to use surplus plutonium to make MOX fuel also required that surplus plutonium be converted to plutonium oxide. In the early 2000s, NNSA had planned to build a facility—the Pit Disassembly and Conversion Facility at SRS—that was to be dedicated to disassembling pits and converting them to plutonium oxide to meet the high plutonium oxide production requirements for manufacturing MOX fuel. Because of its high costs, however, NNSA canceled the Pit Disassembly and Conversion Facility in January 2012 after having spent $730.1 million on its design, as we reported. In August 2012, DOE provided a report to Congress that described a mix of plutonium oxide production capabilities to replace the canceled Pit Disassembly and Conversion Facility. According to the 2012 report, DOE planned to convert at least 2 MT of surplus plutonium pits to plutonium oxide by 2018 in PF-4 at LANL and an additional 3.7 MT of plutonium oxide at SRS by 2017. According to its 2012 report, NNSA planned for this plutonium oxide to be a reserve of advance feedstock for the MFFF. NNSA anticipated it would begin operations in 2019. According to NNSA, SRS turned out not to be cost-effective at producing plutonium oxide. Specifically, SRS produced 35 kilograms (0.035 MT) of plutonium oxide at SRS’s H Canyon facility over a 2.5-year period ending in 2018. NNSA discontinued plutonium oxide production at H Canyon and focused its plans on expanding ARIES operations at PF-4. According to NNSA, ARIES operations at PF-4 currently host the nation’s only cost-effective plutonium oxide production capability. In 1998, DOE established ARIES at PF-4 at LANL in New Mexico as a technology demonstration project to dismantle pits and convert plutonium metal into an oxide, incorporating automation to reduce liquid waste and workers’ exposure to radiation. ARIES’s technology for converting plutonium to plutonium oxide was designed to generate very little chemical waste and to permit the application of automation, which significantly reduces the risk of workers’ exposure to radiation. Pits have historically been disassembled by a cutting machine. Before ARIES’s technology, recovery of plutonium from cut pits was by an aqueous process—that is, by using liquid chemical processing—which generated significant volumes of both liquid and solid waste. In 2008, NNSA shifted the ARIES mission from a technology demonstration project to a small plutonium oxide production capability. According to NNSA officials, ARIES has produced approximately 1 MT of plutonium oxide from pits since it was established in 1998, with peak production of 242 kilograms (0.242 MT) in 2011 during a partial year of operations. NNSA officials explained that ARIES did not produce larger amounts of plutonium oxide because the agency was still evaluating alternatives for expanding plutonium oxide, but they estimated that ARIES could produce 300 kilograms to 400 kilograms in a full year of operations. In addition, LANL shut down the PF-4 facility, including ARIES, from June 2013 through September 2016 to correct safety and operational issues. During this time, plutonium oxide production using ARIES in PF-4 was suspended. Plutonium oxide is the preferred form for long-term storage of plutonium because it is relatively stable compared to other forms. Plutonium oxide is also the form of plutonium that is most suited for dilution. ARIES consists of glove boxes, furnaces, and other equipment to dismantle a pit and extract the plutonium; convert the plutonium into an oxide form; mill and blend the plutonium oxide; conduct physical and chemical analyses of the plutonium oxide; and package and store the plutonium oxide for eventual disposition. NNSA’s 2018 conceptual plan to dilute and dispose of surplus plutonium calls for plutonium metal to be converted to plutonium oxide using ARIES at PF-4 and then for the plutonium oxide to be diluted at SRS for eventual disposal at WIPP. Figure 4 shows the dilute and dispose strategy as described in NNSA’s 2018 conceptual plan. DOE could convert 43.8 MT, or about 77 percent, of surplus plutonium in its inventory of 57.2 MT to plutonium oxide for dilution and disposal because this plutonium is in a metal form suitable to oxidation, based on our review of DOE’s inventory of surplus plutonium. Most of this surplus plutonium metal—33.3 MT—is in the form of pits and is managed by NNSA. EM manages 6.5 MT of surplus plutonium metal and NE manages the remaining 4 MT of surplus plutonium metal reactor fuel at Idaho National Laboratory. Separately, EM also manages 6.4 MT of surplus plutonium that is already in oxide form. Figure 5 shows the forms of surplus plutonium in DOE’s inventory of 57.2 MT of surplus plutonium requiring disposition. As noted above, EM manages 6.4 MT, or 11 percent, of surplus plutonium that already exists as plutonium oxide. According to NNSA officials, SRS is currently diluting this oxide at a modest rate of about 20 kilograms (0.02 MT) annually. According to NNSA documents, the agency plans to add additional throughput capacity within a decade. The remaining 7 MT of surplus plutonium, or about 12 percent of DOE’s surplus plutonium inventory, is contained in spent nuclear fuel and is not suitable for conversion to plutonium oxide. This material would require additional chemical processing steps to make it suitable for conversion to plutonium oxide. DOE officials said that they planned to dispose of the 7 MT of spent nuclear fuel in a deep geologic repository, which would avoid necessitating development of facilities and processes for conversion to plutonium oxide. DOE officials said that this fuel could also be disposed of through other to-be-determined disposition paths. Currently, EM manages the spent nuclear fuel that contains 7 MT of this surplus plutonium at various locations throughout the country. NNSA’s 2018 conceptual plan calls for converting 26.2 MT of surplus plutonium into oxide by 2045. In September 2019, NNSA approved the production of about 1.2 MT of plutonium oxide through 2025 at LANL. However, plans for converting additional surplus plutonium into plutonium oxide are uncertain primarily because of two issues. These issues are (1) NNSA’s plans for new pit production, which are still in development and which will also take place at LANL; and (2) issues surrounding the agency’s ability to ship newly produced plutonium oxide for dilution to DOE’s Savannah River Site (SRS) in South Carolina. According to agency officials, NNSA and DOE are taking several actions that, if successfully implemented, are designed to allow NNSA to meet its long- term plutonium oxide production goals. These actions include continuing to review plutonium oxide and pit production plans, increasing plutonium storage at LANL, reducing the amount of SRS’s surplus plutonium, and shipping the diluted plutonium from SRS to WIPP. NNSA’s 2018 conceptual plan called for expanding plutonium oxide production capacity in PF-4 for the dilute and dispose strategy to achieve production of 1.5 MT per year by 2033. NNSA planned to sustain this rate of production at LANL for 12 years to convert a total of 26.2 MT of pits to plutonium oxide before ramping down operations in 2045. The agency’s 2018 conceptual plan estimated that this increased production would cost approximately $5 billion over the life of the program. To achieve the 1.5 MT annual production rate, NNSA planned to expand the physical space of ARIES’s operations in PF-4 by about 50 percent, install new equipment such as glove boxes, purchase additional equipment, such as spare parts and new shipping containers, and hire over 200 new staff. To accommodate the larger workforce, NNSA also planned to construct a new employee entrance in PF-4. In September 2019, NNSA approved a short-term plan to produce a total of nearly 1.2 MT of plutonium oxide at PF-4 from 2019 through 2025. This short-term plan closely matches the total plutonium oxide production outlined in NNSA’s 2018 conceptual plan for the same time frame. In February 2019, NNSA officials said that they were reevaluating the agency’s long-term plutonium oxide production goals in the 2018 conceptual plan because of two key issues. These issues are space constraints relating to (1) the agency’s mission to produce new pits in PF- 4 and (2) requirements to remove plutonium from SRS. According to agency officials, NNSA and DOE are taking several actions designed to allow NNSA to meet the long-term plutonium oxide production goals described in its 2018 conceptual plan. As we reported in November 2018, NNSA officials said that a planned nuclear weapons refurbishment and future warhead programs will require the production of new pits. Almost all of the pits in the current U.S. nuclear weapons stockpile were produced before 1990, according to a May 2015 Congressional report. In May 2018, NNSA announced that it intended to build 30 pits annually in PF-4 at LANL by 2026 and 50 pits annually at the MFFF at SRS by 2030, under a plan to repurpose the MFFF for pit production. According to an August 2019 LANL presentation to potential subcontractors, this effort will include the installation of more than 140 new gloveboxes or other enclosures in PF-4 and the construction of more than 700,000 square feet of supporting infrastructure (such as offices, a parking garage, and a cafeteria). The President’s budget for fiscal year 2020 includes over $3 billion for this effort through 2024. In April 2019, the NNSA Administrator said meeting pit production requirements was the agency’s highest infrastructure priority. NNSA also may have to increase pit production at LANL beyond 30 pits per year. For example, in May 2018 the Nuclear Weapons Council stated that it was essential that NNSA provide resources for surge pit production capacity in PF-4 at LANL until pit production is fully established at SRS. In addition, the National Defense Authorization Act for fiscal year 2019 requires the Department of Defense and NNSA to contract with a federally funded research and development center to conduct an assessment of, among other things, a strategy for producing 80 pits per year at LANL. NNSA officials told us in February 2019 that as a result of pit production requirements, the agency might need to use a portion of the processing areas in PF-4 for pit production that the agency had planned to use for plutonium oxide production. Pit production requirements also may use more space in the high-security vault in PF-4 where plutonium must be temporarily stored. Also in February 2019, NNSA officials said that PF-4’s high-security storage space is already near full capacity and that pit production may demand storage space that NNSA had planned to use for plutonium oxide production. NNSA officials said that the agency is taking some actions that are designed to address increasing both pit and plutonium oxide production in PF-4. If successfully implemented, these actions are designed to allow the program to meet the milestones described in the 2018 conceptual plan, according to NNSA officials. These actions include: Reviewing use of operational space in PF-4. LANL reported in March 2019 that the requirement to produce 30 pits per year would have no significant negative impact on plutonium oxide production. However, LANL reported that a number of programs, including pit production, were planning to increase operations in PF-4, placing demands on the aging facility that could lead to more frequent maintenance outages. In August 2019, NNSA officials responsible for plutonium oxide production and pit production said they continue to believe that increased oxide production and pit production can be simultaneously accomplished in PF-4 but that they are continuing to review the issue as the agency’s pit production plans evolve. In NNSA’s comments on our report, the NNSA Administrator said the agency was working to balance the needs of both missions. The Administrator also noted that NNSA’s Office for Cost Estimating and Program Evaluation will assess the effect of plutonium oxide production on pit production as required by section 3120 of the National Defense Authorization Act for fiscal year 2019. The conference report accompanying the act also requires that we review this assessment, which we will initiate in late 2019. Increasing plutonium storage capacity. LANL also reported in March 2019 that it planned to implement several mitigation measures that would allow the storage of more plutonium oxide and other materials in the PF-4 vault. In addition, DOE and NNSA have “swapped” 1 MT of the declared surplus plutonium at SRS with 1 MT of plutonium residues and other primarily non-pit plutonium already stored in LANL’s PF-4 vault. NNSA officials said that the plutonium residues and other primarily non-pit plutonium at LANL would be considered surplus plutonium and would be converted to plutonium oxide, requiring less storage space. Without these mitigation measures, the PF-4 vault would fill up years earlier, according to NNSA officials. NNSA officials said they believe the swap will increase storage space through 2028, at which point LANL would need to ship plutonium oxide to SRS or face a suspension of plutonium oxide production. Storing quantities of plutonium oxide in PF-4’s high-security storage vault is critical because, according to NNSA officials, it is not likely that NNSA will ship plutonium oxide or other forms of plutonium to SRS until a dispute with the state of South Carolina is resolved. Specifically, the National Defense Authorization Act for fiscal year 2003 required DOE to prepare a plan for the construction and operation of the MFFF at SRS so that it could produce MOX fuel at an average rate of at least 1 MT per year. As subsequently amended, the law provides that if DOE did not meet this 1 MT production objective by January 1, 2014, then it was required to remove 1 MT of defense plutonium from South Carolina by January 1, 2016. If DOE missed that deadline, it was required to make substantial payments to South Carolina until the removal was completed. As NNSA faced delays and cost increases in constructing the MFFF and began to reevaluate its surplus disposition strategy, South Carolina sued DOE in February 2016 to begin removing plutonium from the state and to begin to make payments to the state of up to $100 million per year until the surplus plutonium is removed. In December 2017, the court ordered DOE to remove 1 MT of plutonium from South Carolina by 2020. In response, according to court filings, NNSA moved 0.5 MT of plutonium from SRS to its Nevada National Security Site prior to November 2018 and moved another 0.5 MT of plutonium off-site in August 2019. DOE is still required by statue to remove an amount of defense plutonium or defense plutonium material equal to that which was transferred to SRS after April 15, 2002, but not processed by the MOX facility by January 2022. The officials told us that because of this continuing requirement and the threat of further lawsuits by South Carolina, it was unlikely that NNSA could ship plutonium oxide to SRS until the surplus plutonium at SRS is removed. NNSA officials said that the agency is taking some actions designed to address these issues. These actions include: Increasing plutonium oxide production rates with a priority on oxidizing plutonium material from SRS. NNSA officials said in August 2019 that they are in discussions with LANL to increase the short-term production of plutonium oxide to speed the removal of surplus plutonium from South Carolina. According to NNSA officials, NNSA and LANL are considering increasing plutonium oxide production through 2025 beyond what is called for in their short-term plan that the agency approved in September 2019. This would involve shipping additional surplus plutonium metal from SRS to LANL and prioritize converting this material to plutonium oxide. According to agency officials, LANL would produce additional plutonium oxide production by using new ARIES equipment installed in PF-4 in 2019. To achieve this increased production, NNSA officials said that LANL would need to hire 70 personnel through 2025 to operate ARIES. Agency officials said that these steps would increase total plutonium oxide production to approximately 2.1 MT through 2025, an increase of nearly 1 MT over the short-term plan NNSA approved in September 2019. Increasing dilution and disposal rates of the inventory of plutonium oxide already at SRS. DOE and NNSA officials said that they would also increase dilution of existing plutonium oxide at SRS beyond what is called for in the 2018 conceptual plan to help reduce the inventory of plutonium metal already there. In April 2019, NNSA officials said their current dilution rate at SRS was about 20 kilograms (0.02 MT) annually, but that they plan to increase that rate to 1.5 MT by the late 2020s. Under its 2018 conceptual plan, NNSA had planned to achieve that dilution rate by 2031, but the budget request for NNSA for fiscal year 2020 shows that NNSA plans to complete installation of the capability necessary to achieve that dilution rate by as early as fiscal year 2028. The effort—known as the Surplus Plutonium Disposition project—has an estimated cost range from $200 million to $589 million. It includes removing unnecessary equipment from SRS, accelerating the project’s construction schedule, installing long-lead procurement items early in construction, and hiring and certifying additional personnel. According to NNSA officials, this increase in dilution capacity by 2028 would enable NNSA to begin shipping plutonium oxide to SRS for dilution and disposal without suspending plutonium oxide production at PF-4. While NNSA is taking actions to address pit production and shipment issues, the agency continues to work on refining the long-term plutonium oxide production goals in its 2018 conceptual plan. However, NNSA officials said that establishing firm long-term plutonium oxide production plans now would be premature and that the agency would use the next several years to balance plutonium oxide production, pit production, and shipment issues as they refine long-term production plans. We provided a draft of this report to NNSA and DOE for review and comment. In its response to our draft report, reproduced in appendix V, NNSA said that it and DOE are working to balance the needs of its dilute and dispose program, which includes oxide production, and pit production, as well as the need to remove plutonium from the state of South Carolina. NNSA said, as noted in our report, that its Office for Cost Estimating and Program Evaluation would assess the effects of increased plutonium oxide production on pit production. NNSA also said that even with delays in production of plutonium oxide, the dilution and disposition of surplus plutonium will still be substantially less expensive than if the agency had maintained its MOX fuel approach. As stated in our report, we have a large body of work that has examined the MOX fuel approach, NNSA’s management of the MOX project, and DOE’s $17 billion cost estimate to complete the project, which we assessed as being reliable. In addition, NNSA provided us with technical comments and additional documentation, which we incorporated into our report as appropriate. Some of the information that NNSA provided helped clarify near-term plutonium oxide production plans as well as the agency’s progress in balancing the plutonium oxide production plans, pit production, and the need to move plutonium out of the state of South Carolina. This information is incorporated in our report and is reflected in the report’s revised title. We are sending copies of this report to the appropriate congressional committees, the Secretary of Energy, and other interested parties. In addition, this report is available at no charge on the GAO website at http://www.gao.gov. If you or your staff members have questions about this report, please contact me at (202) 512-3841 or trimbled@gao.gov. Contact points for our Offices of Congressional Relations and Public Affairs may be found on the last page of this report. GAO staff who made key contributions to this report are listed in appendix VI. Our report (1) determines the amount of surplus plutonium in the Department of Energy’s (DOE) inventory that could be converted to plutonium oxide for dilution and disposal and (2) examines DOE’s capacity to produce plutonium oxide. To determine the amount of surplus plutonium in DOE’s inventory that could be converted to plutonium oxide for dilution and disposal, we reviewed relevant DOE documents and interviewed officials from DOE, including from DOE’s National Nuclear Security Administration (NNSA) and DOE’s Office of Environmental Management (EM), on the amounts and forms of surplus plutonium in DOE’s inventory that would require conversion to an oxide prior to final disposition. Our review included DOE’s plans for converting surplus plutonium to plutonium oxide beginning in 1997, when DOE first decided to convert surplus plutonium to plutonium oxide for disposition. We also visited the Los Alamos National Laboratory (LANL) in New Mexico to review documentation and interview officials in the Surplus Plutonium Disposition Program for information on past and current inventories of surplus plutonium. NNSA’s Advanced Recovery and Integrated Extraction System (ARIES), the program that currently converts surplus plutonium to plutonium oxide, resides in Plutonium Facility-4 (PF-4) at LANL. To examine DOE’s capacity to produce plutonium oxide, we reviewed relevant DOE documents and interviewed officials from DOE, including from NNSA and EM, on the status of plutonium oxide production in PF-4 and at DOE’s Savannah River Site, where surplus plutonium was converted to plutonium oxide over a 2 1/2-year period. We reviewed relevant DOE documents and interviewed officials from DOE, including from NNSA and EM, on their plans. For example, we reviewed records of decision and environmental impact statements that DOE issued during its management of the Surplus Plutonium Disposition Program. We reviewed planning documents related to the dilute and dispose strategy, including DOE’s life-cycle cost estimate and supporting documents covering issues such as time frames and conversion rates. We visited the ARIES program in PF-4 in January 2018 to review documentation and conduct interviews with officials responsible for plutonium oxide production and the planned expansion of plutonium oxide production. The site visit included a tour of PF-4, ARIES and its operations, and potential spaces in PF-4 for expansion of ARIES operations for converting surplus plutonium metal to oxide. We conducted this performance audit from October 2017 to October 2019 in accordance with generally accepted government auditing standards. Those standards require that we plan and perform the audit to obtain sufficient, appropriate evidence to provide a reasonable basis for our findings and conclusions based on our audit objectives. We believe that the evidence obtained provides a reasonable basis for our findings and conclusions based on our audit objectives. DOE first established the Surplus Plutonium Disposition Program in 1997 to dispose of surplus, weapons-usable plutonium at the end of the Cold War. As of April 2019, the United States has declared a total of 61.5 metric tons (MT) of plutonium as surplus to defense needs. DOE has disposed of 3.2 MT of surplus plutonium at the Waste Isolation Pilot Plant (WIPP), an underground repository for transuranic waste located near Carlsbad, New Mexico, and is in the process of disposing of an additional 1.1 MT of surplus plutonium. This leaves 57.2 MT of surplus plutonium in its inventory, as of May 2019. The table below shows the timeline of changes to DOE strategies for managing surplus plutonium for final disposition. 1997 - DOE announces the Surplus Plutonium Disposition Plan, including the Mixed Oxide Fuel Fabrication Facility (MFFF). 2000 - The United States and Russia enter into the Plutonium Management and Disposition Agreement (PMDA), each agreeing to dispose of at least 34 metric tons (MT) of plutonium at a rate of at least 2 MT per year. 2000 - DOE announced it will construct the MFFF. 2002 - The National Defense Authorization Act for fiscal year 2003 requires DOE to prepare a plan for the construction and operation of the MFFF at the Savannah River Site in South Carolina and requires, among other things, that DOE remove 1 MT of plutonium from South Carolina by January 1, 2011, if mixed oxide (MOX) production objectives of an average rate of at least 1 MT per year were not achieved by January 1, 2009. Failure to meet these deadlines would require DOE to make substantial annual payments to South Carolina. 2005 – The Energy and Water Development Appropriations Act for Fiscal Year 2006 extends the original plutonium production and removal deadlines by 3 years (thus making the 1 MT plutonium production deadline January 1, 2012, and removal deadline January 1, 2014). 2014 – The National Defense Authorization Act for fiscal year 2015 requires DOE to issue a report that would study the plan for the MFFF as well as possible alternatives to the MFFF. 2015 - The National Defense Authorization Act for Fiscal Year 2016 requires DOE to carry out an analysis of alternatives for the Surplus Plutonium Disposition Program. 2015 and 2017 - Explanatory statements accompanying fiscal years 2016 and 2017 appropriations legislation contained specific direction to explore design issues associated with the dilute and dispose alternative. 2016 - South Carolina sues DOE in federal district court, contending that DOE failed to meet the MOX-related statutory deadlines. South Carolina sought monetary relief and an injunction compelling the federal government to remove 1 MT of plutonium from the state. 2016 - DOE issues a Record of Decision stating that it would remove plutonium from South Carolina using the dilute and dispose strategy. 2017 - Federal district court issues an injunction ordering DOE to remove 1 MT of plutonium from South Carolina and ordering the parties to negotiate a new deadline. 2017 - The National Defense Authorization Act for Fiscal Year 2018 allowed DOE to terminate construction of MFFF if, among other things, DOE identified an alternative that would cost less than half of the MOX fuel strategy. 2017 - South Carolina and DOE fail to agree on a deadline for removing 1 MT of plutonium from the state, so in December the court imposes a deadline of January 1, 2020. 2018 - Federal appellate court rejects DOE’s appeal of the district court’s order to remove 1 MT of plutonium from South Carolina by January 1, 2020. 2018 - DOE terminates the MOX contract for the government’s convenience. 2019 – DOE acknowledges that it had shipped 0.5 MT of plutonium from South Carolina to Nevada sometime before November 2018 and shipped an additional 0.5 MT out of South Carolina to another state sometime before August 2019. The Nuclear Waste Policy Act of 1982 directed, among other things, that DOE study sites for a repository and that the President evaluate the capacity for the disposal of high-level waste resulting from atomic energy defense activities at one or more repositories developed for the disposal of commercial used (spent) nuclear fuel. In 1985, President Reagan found that there was no basis to conclude that a separate defense high- level waste repository was required. Table 2 shows the changes in plans for developing a high-level waste repository from 2002 through 2018. In addition to the individual named above, the following individuals made contributions to this report: Jonathan Gill (Assistant Director); Robert Sánchez (Analyst in Charge); Antoinette Capaccio; Robert (Scott) Fletcher; Cindy Gilbert; Richard Johnson; Sheryl Stein; Sara Sullivan; and Curtis (Wade) Tanner.

Summary: The United States has 57.2 MT of weapons-usable plutonium that it has declared surplus and that still requires disposition. This plutonium exists in various metal and non-metal forms, including pits—the central core of a nuclear weapon. To prevent insidious use of this plutonium, DOE plans to disassemble pits into metal; convert the plutonium metal to plutonium oxide, a powder-like substance; dilute it with inert material; and dispose of it at WIPP. In May 2018, NNSA issued a plan conceptualizing the dilution and disposal of 34 MT of surplus plutonium at an estimated cost of $19 billion over the next 3 decades. Under this conceptual plan, pit disassembly and production of plutonium oxide would take place at one facility and dilution would be performed in another, with both operations expanding over the next decade. GAO was asked to review DOE's plans for plutonium oxide production to dispose of surplus plutonium. This report (1) examines the amount of surplus plutonium in DOE's inventory that could be converted to plutonium oxide for dilution and disposal and (2) examines DOE's capacity to produce plutonium oxide. GAO reviewed the inventory of surplus plutonium, plutonium oxide production requirements and production capacity, and DOE planning documents, and interviewed DOE officials. Of the Department of Energy‘s (DOE) inventory of surplus plutonium, about 43.8 metric tons (MT), or 77 percent, is plutonium metal that could be converted to plutonium oxide for dilution and disposal. Of this amount, the National Nuclear Security Administration (NNSA) manages 33.3 MT in the form of pits, DOE's Office of Environmental Management (EM) manages 6.5 MT, and DOE's Office of Nuclear Energy manages 4 MT in the form of reactor fuel. EM manages another 11 percent, or 6.4 MT, of DOE's surplus plutonium that is already in oxide form. Most of this is suitable for dilution and disposal at the Waste Isolation Pilot Plant (WIPP), a repository in New Mexico. An additional 12 percent, or 7 MT, of DOE's surplus plutonium is contained in spent nuclear fuel that is planned for disposal in a geologic repository. See figure. NNSA's 2018 conceptual plan calls for converting 26.2 MT of this surplus plutonium into oxide by 2045. In September 2019, NNSA approved the production of about 1.2 MT of plutonium oxide through 2025 at its Los Alamos National Laboratory (LANL) located in New Mexico. However, plans for converting additional surplus plutonium into plutonium oxide are uncertain because of two issues. These issues include NNSA's still-developing plans for new pit production, which will also take place at LANL, and issues surrounding the agency's ability to ship newly produced plutonium oxide for dilution to DOE's Savannah River Site (SRS) in South Carolina. According to agency officials, NNSA and DOE are taking several actions that, if successfully implemented, are designed to allow NNSA to meet its long-term plutonium oxide production goals. These actions include continuing to review plutonium oxide and pit production plans, increasing plutonium storage at LANL, reducing the amount of SRS's surplus plutonium, and accelerating the shipment of diluted plutonium from SRS to WIPP.