The Office of Fissile Materials Disposition is responsible for disposing of inventories of surplus US weapons-usable plutonium and highly enriched uranium as well as providing, technical support for, and ultimate implementation of, efforts to obtain reciprocal disposition of surplus Russian plutonium. On January 4, 2000, the Department of Energy issued a Record of Decision to dispose of up to 50 metric tons of surplus weapons-grade plutonium using two methods. Up to 17 metric tons of surplus plutonium will be immobilized in a ceramic form, placed in cans and embedded in large canisters containing high-level vitrified waste for ultimate disposal in a geologic repository. Approximately 33 metric tons of surplus plutonium will be used to fabricate MOX fuel (mixed oxide fuel, having less than 5% plutonium-239 as the primary fissile material in a uranium-235 carrier matrix). The MOX fuel will be used to produce electricity in existing domestic commercial nuclear reactors. This paper reports the major waste-package-related, long-term disposal impacts of the two waste forms that would be used to accomplish this mission. Particular emphasis is placed on the possibility of criticality. These results are taken from a summary report published earlier this year.

First published in 1997, this volume observes that of all the materials, systems and facilities that designed and operated nuclear weapons, the most readily available assets for reuse are often identified as the highly enriched uranium (HEU) and plutonium from warheads. However, proliferation concerns the reuse of much of this material unlikely. This book explores the economic issues surrounding the major expenditures facing the US as it attempts to dispose of weapon-grade nuclear materials in a proliferation-resistant manner. The book discusses the economic values of plutonium and HEU, the economic nature of the nuclear industry, reprocessing and operations costs, the economics of ‘burning’ plutonium to generate electrical power, the economics of down-blending and ‘burning’ HEU, military conversion as a rationale for selecting plutonium disposition options, the economics of transmutation, and the economics of other proposals ranging from monitored surface storage to vitrification. The book concludes by identifying the major cost drivers affecting all disposition options.

This NATO Advanced Research Workshop on Disposal of Weapons Plutonium is a follow-up event to two preceding workshops, each dealing with a special subject within the overall disarmament issue: "Disposition of Weapon Plutonium", sponsored by the NATO Science Committee. The first workshop of this series was held at the Royal Institute of International Affairs in London on 24-25 January 1994, entitled "Managing the Plutonium Surplus, Applications, and Options". Its over all goal was to clarify the current situation with respect to pluto nium characteristics and availability, the technical options for use or disposal, and their main technical, environmental, and economic constraints. In the immediate term, plutonium recovered from dismantled nuclear warheads will have to be stored securely, and under international safeguards if possible. In the intermediate term, the principal alter natives for disposition of this plutonium are: irradiation in mixed oxide (MOX) fuel assemblies in existing commercial light-water reac tors or in specially adapted light-water reactors capable of operation with full cores of MOX fuel .and irradiation in future fast reactors. Another option is to blend plutonium with high-level waste as it is vitrified for final disposal in a geologic repository. In both cases, the high radioactivity of the resulting products provides "self shielding" and prevents separation of plutonium without already developed and available sophisticated technology. The so-called "spent fuel standard" as an effective protection barrier is - quired in either case.

The end of the cold war left the United States with a surplus of weapons-grade plutonium. Much of this material is found in a key nuclear weapon component known as a pit. In 1997, DOE announced a plan to dispose of surplus, weapons-grade plutonium through an approach that included fabrication of plutonium into MOX fuel for use in domestic commercial nuclear reactors. In 2000, the United States and Russia entered into a Plutonium Management and Disposition Agreement, in which each country pledged to dispose of at least 34 metric tons of surplus, weapons-grade plutonium. Through a protocol to the agreement signed in 2010, the United States and Russia reaffirmed their commitment to dispose of surplus, weapons-grade plutonium as MOX fuel in nuclear reactors, and the agreement entered into force in 2011.

The United States has pledged to dispose of 34 metric tons of surplus, weapons-grade plutonium. The current U.S. approach relies on disposing of the plutonium by irradiating it as MOX fuel-a mixture of plutonium and uranium oxides-in modified commercial nuclear reactors. Due to a significant rise in cost, DOE recently proposed terminating the MOX approach in favor of the dilute and dispose approach, which DOE stated may be less expensive. Under this approach, plutonium would be diluted with inert material and then disposed of in a geologic repository. GAO was asked to review DOE's planning for both the MOX and dilute and dispose approaches. This report examines: (1) the extent to which DOE's revised cost estimates for completing the construction of the MOX facility and for completing the overall Plutonium Disposition Program met best practices, (2) the status of NNSA's development of a life-cycle cost estimate for the dilute and dispose approach, and (3) the extent to which DOE has sufficient disposal space and statutory capacity at WIPP to dispose of all defense TRU waste, including waste from the dilute and dispose approach. GAO reviewed documents and interviewed DOE and NNSA officials, including officials from five major waste-generating sites.

The United States has pledged to dispose of 34 metric tons of surplus, weapons-grade plutonium. The current U.S. approach relies on disposing of the plutonium by irradiating it as MOX fuel—a mixture of plutonium and uranium oxides—in modified commercial nuclear reactors. Due to a significant rise in cost, DOE recently proposed terminating the MOX approach in favor of the dilute and dispose approach, which DOE stated may be less expensive. Under this approach, plutonium would be diluted with inert material and then disposed of in a geologic repository. This report examines: (1) the extent to which DOE’s revised cost estimates for completing the construction of the MOX facility and for completing the overall Plutonium Disposition Program met best practices, (2) the status of NNSA’s development of a life-cycle cost estimate for the dilute and dispose approach, and (3) the extent to which DOE has sufficient disposal space and statutory capacity at WIPP to dispose of all defense TRU waste, including waste from the dilute and dispose approach. GAO is making four recommendations, including that DOE develop a plan for expanding WIPP’s disposal space that includes a schedule for completing the expansion before existing space is full.