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This presentation explores the use of thorium in disposing of weapons-grade plutonium, developing proliferation-resistant fuels, and achieving long-term goals of US initiatives. It discusses the history of weapons-grade plutonium, the challenges with implementing MOX fuel, the potential of thorium-based fuels, and the possibility of molten salt reactors. Recommendations for further research and funding are provided.
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Thorium for Use in Plutonium Disposition, Proliferation Resistant Fuels, and Future Reactors Brian Johnson WISE 2006 ANS johnsob6@onid.orst.edu
This presentation focuses on the following uses of thorium • Weapons-Grade Plutonium disposition • Proliferation-resistant fuels for developing countries • Reaching long-term goals of U.S. initiatives http://www.ornl.gov/sci/ees/images/nnp_bomdstobulb.gif http://www.crwflags.com/fotw/images/q/qt-p-nb.gif http://www.usembassy.it/file2006_02/alia/a6022102.jpg http://afci.lanl.gov/images/AFCI_Gold_Logo.jpg http://gif.inel.gov/images/forum_animation_08.gif
History of Weapons-Grade Plutonium • During the Cold War the United States and Soviet Union made vast arsenals of nuclear weapons • In 1994 the National Academy of Science deemed the stockpiles a "clear and present danger to national and international security." http://www.iaea.org/inis/aws/fnss/fulltext/te_1319_31.pdf
U.S./Russia Parallel Disposition • In 2000 the U.S. and Russia formally agreed to the disposition of 34 metric tons of weapons-grade plutonium each • The final form of the plutonium must meet the “spent-fuel standard” • Mixed oxide (MOX) fuel using weapons-grade plutonium was agreed upon as the best method
MOX Woes • The original goal was to implement MOX by 2007 and disposition 2 metric tons per year • This goal will not be reached due to lack of funding in Russia, management problems, and delays in the U.S. • The House and Senate have authorized limited funding until the Secretary of Energy can make some certifications
Given Sunk Costs of MOX, compared to other technologies MOX is still the best option The Department of Energy has an action plan to fix management problems An independent cost estimate of the MOX project the Department of Energy intends to use MOX regardless of what Russia decides to do Secretary of Energy Must Certify House Requirements: Senate Requirements:
Thorium as an option • Thorium-based fuels designed for plutonium disposition are more than twice as effective at disposing plutonium than MOX • Fewer, or no modifications to current reactors • Around two to three years from implementation
Recommendation • A $4 million dollar program pursuing thorium-based fuel design for use in U.S. reactors should be pursued • This could be sponsored by those who have supported the funding for the program in Russia, such as Curt Weldon http://www.thoriumpower.com/images/elmash%20fuel%20assembly.jpg
Proliferation-Resistant Fuels for Developing Countries • The U.S. outlines a desire in GNEP to help developing countries set up nuclear power • These facilities will provide potable water, heat for industrial processes and electricity • They are in less secure areas and must be inherently more resistant to proliferation • Small reactors with long fuel lives and low plutonium output are recommended • Thorium-based fuel designed for proliferation resistance can meet some of these goals
India, Canada, and Heavy Water Reactors • If developing nations are not provided with more proliferation resistant technologies they may choose heavy water reactors • No need for pressure vessel • No need for enrichment • Spent-fuel from heavy water reactors contains plutonium between weapons-grade and typical reactor grade • India used plutonium from their first heavy water reactor to build their first weapon
Features of Thorium-Based Proliferation-Resistant Fuels • Annual plutonium output is reduced by a factor of 7 • The fissile percentage in the discharged plutonium is around 60%, compared to around 70% in typical spent fuel • Heat generation of plutonium increase • Weapons made of discharged plutonium are more likely to “fizzle”
Recommendation • While thorium-based fuels aren’t a perfect answer, it is better to take steps now to assure some extra level of proliferation resistance • Since the fuel design is very similar to the plutonium disposition design, the research program recommended before could also include a proliferation resistant design at a marginal extra cost
Long-Term Goals • The Advanced Fuel Cycle Initiative as a major part of GNEP • Generation IV Initiative • Basic objectives • Reduce Waste • Improve Economics • Improve Proliferation-Resistance
Molten Salt Reactor: A Possible Solution • Meets all goals set forth by both the AFCI and the Gen-IV Initiative, notably a top rating in sustainability • U.S. operating experience, yet no current funding http://nuclear.inl.gov/gen4/i/msr.gif
Molten Salt Reactor Issues • Technical Barriers • Proliferation resistant characteristics • Cost to operate • Recent research on AMSTER in France shows issues to be resolvable especially if optimized for waste recution http://nuclear.inl.gov/gen4/i/msr.gif
Recommendations • The United States must do a modern system-wide analysis comparing the current GNEP plan to molten salt reactors • If found to be a competitive solution, the United States should fund some research to advance molten salt reactor technology through the AFCI, Gen-IV, or both
Summary • Thorium technologies could help reach some United States political goals and should be researched for: • Plutonium Disposition • Proliferation Resistant Fuel • Molten Salt Reactor