Improving the Scientific Basis for Managing DOE's Excess Nuclear Materials and Spent Nuclear Fuel (2003) / Chapter Skim
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Appendix A: Nuclear Materials Production in the DOE Complex
Appendix A: Nuclear Materials Production in the DOE Complex
Pages 95-101
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To provide a context for the nuclear materials and spent fuel challenges and research opportunities described in this report, these activities can be grouped into seven major processes: · mining, milling, and refining of uranium; . isotope separation of uranium, lithium, boron, and heavy water; · fuel and target fabrication for production reactors; · reactor operations to irradiate fuel and targets to produce nuclear materials; · chemical separations of plutonium, uranium, and tritium from irradiated fuel and target elements; · component fabrication of both nuclear and nonnuclear components; and · weapon operations, including assembly, maintenance, modification, and dismantlement of nuclear weapons.
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nuclear materials production activities was to produce plutonium for nuclear weapons. Enriched uranium served as fuel in production reactors, and excess neutrons from the nuclear chain reaction bred Pu-239 and other isotopes in "targets" made of U-238.
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Except for a few special cases, such as research reactor fuel, the highly radioactive spent fuel and targets were reprocessed to recover plutonium, uranium, and other isotopes and to separate waste materials. However, when the United States stopped its plutonium production in 1992, some spent fuels, including targets, were left unreprocessed.
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From page 100... ...
Operation of F-Canyon restarted in 1959, and H-Canyon was shut down and modified to maintain nuclear safety while processing HEU driver elements. Changes included dissolver inserts to provide safe geometry, lowered concentration of the tributylphosphate extractant, and instruments to monitor and control concentrations of the uranium in the liquid phases.
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From page 101... ...
Special plutonium irradiation campaigns were made to produce various isotopic compositions of plutonium that would be approached in a plutonium breeder economy where plutonium would be recycled back into fuel.These materials went to tests to determine reactor neutronic characteristics at different stages of plutonium recycle operation.The H-Canyon B-Line can process Np-237, Pu-238, and Pu-239.The F-Canyon B-Line recovery can process slags and crucibles from metal production and miscellaneous scrap. As of the summer of 2002, the last plutonium metal has been produced in F B-Line, the liquid system has been flushed, and preparations are under way to put F-Canyon on standby.The F B-Line dry mechanical line will be used to calcite plutonium returns to meet specifications on moisture and volatile materials, utilizing new high-temperature furnaces that can reach the specified firing temperature of 1000 °C.
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