Division Director Discusses Plutonium Future part 2

"and they shall beat their swords into plowshares, and their spears into pruning hooks: nation shall not lift up sword against nation, neither shall they learn war anymore." Isaiah 2:4

Presently there is no international consensus on the disposition of excess plutonium released from weapons dismantlement. An approach that is being considered by most nuclear states, but not by the U.S. at this time, is utilizing plutonium as fuel to extract the available energy. In this context, weapons plutonium can serve as an initial step towards the recycling of plutonium for use in the civilian fuel cycle. There are no technical barriers to this option, but a myriad of timing, political, and fiscal barriers exist. Some of the world's weapons materials are currently vulnerable to diversion, and because of the urgency to reduce the potential of nuclear threats, we can ill afford to wait for the political debate. Current U.S. policy is not to reprocess and recycle plutonium in commercial reactors, and the financial incentives to burn plutonium in nuclear power reactors are lacking in this, the world's most energy-intense nation.

The urgent issue is how to secure excess weapons plutonium against potential theft and diversion while the international debate on disposition policy continues. The National Academy of Sciences has stated that the excess plutonium in the world's stockpile represents a clear and present danger to national security. So the question is: How can we preserve this potentially valuable resource for the future while dealing today's realities? There is a logical appeal to the idea that the solution for dealing with excess plutonium from weapons has a parallel path to that for spent reactor fuel, and that the two paths converge at a decision point 50 years in the future.

The top-level tasks for the weapons plutonium project would be

1. dismantle weapons,
2. stabilize residues,
3. separate plutonium from weapons components and residues,
4. discard the low-level and nonnuclear wastes in permanent repositories,
5. the plutonium into inspectable forms of oxide or metal, and
6. store the plutonium in containers that can be and safeguarded for 50 or 100 years. Then let the and economic debates rage and settle, assuming the conclusion is the peaceful use of the nuclear fuel cycle,
7. convert the plutonium to mixed-oxide fuel,
8. recycle it in reactors, and eventually
9. reprocess and recycle plutonium in reactor fuel cycles.

Technical solutions needed to complete this sequence have been developed as follows:

• disassembly, stabilization, and separation technologies for dismantled weapons and the 50-year legacy wastes well established;
• disposal of nonnuclear waste is economically attractive and more environmentally acceptable than storing high-level radioactive wastes;
• the long-term stability of plutonium oxide and metal is well understood; and storage containers designed to last for 50 years have been fabricated and are in use.

Safeguarding the plutonium seems fairly simple because the amount of estimated excess weapons-grade plutonium metal could fit in two or three pickup trucks. (Of course the trucks would collapse, and the mass would be supercritical, but the image helps to visualize the magnitude of the problem.) One or two storage facilities containing 99.5 metric tons of separated plutonium could be readily safeguarded against theft and diversion for 50 years.

The actions for dealing with spent fuel are somewhat more complicated because of the profuse numbers and the dispersion of spent fuel assemblies around the nation and the globe. An additional 800 metric tons of reactor plutonium are contained-and still growing at about 50 tons per year-in spent nuclear reactor fuel. The spent nuclear fuel, along with about 90 metric tons of separated, reactor-grade plutonium, is presently stored in the 30 countries with civil nuclear power programs. Ironically, the intense radioactivity of spent fuel reduces the threat of its theft and diversion and therefore decreases the urgency of dealing with it. The parallel, top-level tasks for dealing with spent nuclear fuel might be

1. temporary storage in pools, followed by
2. retrievable dry storage in aboveground containers, thereby allowing time to debate the use of plutonium as a future energy source, and assuming the conclusion is the peaceful use of the nuclear fuel cycle,
3. reprocessing spent fuel,
4. discarding the fission product wastes in permanent repositories,
5. fabricating mixed-oxide fuel,
6. recycling the fuel in reactors, and
7. reprocessing and recycling plutonium in advanced reactors.

The energy content of the weapons plutonium in the U.S. has about the same energy content as 100,000,000 metric tons of oil; the energy content of spent fuel could increase the energy available from the once-through uranium cycle by nearly 100 times. This energy source could contribute to worldwide economic stability and reduce worldwide pollution from burning of fossil fuels. The barriers to achieving the vision of Isaiah with weapons-grade plutonium are significant but relatively simple: overcoming the aversion to separate, store, and use weapons-grade plutonium for peaceful uses, and reversing the restrictions on reprocessing and recycling reactor-grade plutonium.

Success depends on nations agreeing with nations on strict safeguarding and security of reactor-grade plutonium; I'm not optimistic, but I'm hopeful. In the meantime, the mission that we are facing is every bit as challenging, technically exciting, and important as the Manhattan Project. Whatever the political decisions and economic drivers; TA-55 will play a key role in developing new technologies for utilizing, managing, and ensuring the safety of the world's plutonium. Bruce Matthews

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