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The remediation of nuclear waste created by conventional fission reactors will rely upon the separation of the waste products for further treatment. The UREX+ process now under review will involve the use of an aqueous chemical process to separate out depleted uranium resulting in a product containing minor actinides, fission products, cesium, strontium, technetium, and iodine. The radioactive decay of strontium and cesium produces roughly half of the thermal and gamma production in spent fuel and the relatively short halflife of isotopes of both of these elements requires storage for about 300 years before heat and radiation decreases to safe levels.

During the separation process, concentrated quantities of fissionable plutonium and americium pose a potential nuclear criticality risk. At each stage in the process, an assessment of the effective neutron multiplication factor, keff, will be necessary to prevent the possibility of sustained fission. Candidate storage containers must also be analyzed to assess the need for radiation shielding. The minor actinides generate significant amounts of heat through radioactive decay and proposed storage must be designed to avoid excessive temperatures.

In the continuation of our work with ANL, we will conduct assessments of nuclear criticality, radiation transport for shielding, and thermal analyses of wastes in the Cs/Sr, Pu/Np, and Cm/Am waste streams to assist in the design of the UREX+ process.


Americium; Cesium; Criticality (Nuclear engineering); Curium; Neptunium; Plutonium; Radioactive wastes; Separation (Technology); Shielding (Radiation); Strontium; Uranium Recovery by Extraction (UREX)

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Criticality (Nuclear engineering); Strontium; Separation (Technology)


Chemistry | Nuclear | Nuclear Engineering | Oil, Gas, and Energy

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528 KB




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