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The completion of criticality experiments for mixtures of higher actinides (HA, includes neptunium, plutonium, americium, and curium) that will be created during the separation of used nuclear fuel has been identified as a requirement to construct prototype plants such as the Engineering-Scale Demonstration (ESD) and the Advanced Fuel Cycle Facility (AFCF) for the Global Nuclear Energy Partnership (GNEP). GNEP is a program to develop a worldwide consensus to enable the expanded use of economical, environmental nuclear energy to meet growing electricity demand. In this program and the Advanced Fuel Cycle R&D program (AFC) that supports it, we are developing economic and environmental methods to reduce the impact of waste from commercial nuclear fuel cycles. Recycling of used fuel by chemically separating it into uranium, fission products, and higher actinides (HA) would be the first step in this new fuel cycle. Proposed mixtures and concentrations of HA covering a wide range of conditions must be examined theoretically and experimentally to demonstrate criticality safety in advance of construction of a processing facility. Theoretical studies may be limited because of insufficient nuclear data for the rarer isotopes of plutonium (Pu), americium (Am), curium (Cm), and neptunium (Np). One aspect of this is a previously indicated positive reactivity coefficient for dilute mixtures of Pu. As MCNP will be used in future design studies, this trend must be confirmed for MCNP. This will also require generation of cross section libraries and thermal scattering (S(α,β)) data bases. In addition, a series of integral criticality experiments will be required to validate computational results. In this project, which is a collaboration between UNLV, LANL, and ORNL, we will study thermal feedback effects in dilute mixtures of Pu, then through parametric studies determine the capabilities of a liquid-core critical assembly to measure these criticality parameters and validate design calculations.


Actinide elements; Americium; Criticality (Nuclear engineering); Curium; Neptunium; Plutonium; Reactor fuel reprocessing; Separation (Technology)

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Actinide element; Criticality (Nuclear engineering); Separation (Technology)


Analytical Chemistry | Chemistry | Oil, Gas, and Energy | Physical Chemistry

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223 KB




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