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The AAA program will rely on the use of an accelerator-based transmuter to expose spent nuclear fuel to high-energy neutrons. The neutron flux will be sufficient to activate or fission the long-lived isotopes of Tc, I, Pu, Am, Cm, and Np that present a significant safety hazard in commercial spent fuel. Transmuter fuel will be subcritical and a high-energy proton accelerator is needed to maintain the necessary neutron flux through the use of a neutron spallation target. The maximum neutron energy produced by spallation (~ 600 MeV) is significantly higher than that produced by a commercial light water reactor (~ 2 MeV). To design the nation’s first transmuter, the neutronics code MCNPX will be used to model the distribution of neutron flux within the fuel blanket and to determine the neutron multiplication, keff. However, the cross section libraries and computational methods used by MCNPX at these neutron energies still have some uncertainty and will require validation.

To lessen the uncertainties in the MCNPX libraries, the Department of Energy, through its national laboratories, is in the process of conducting several experiments utilizing protons produced by the Los Alamos Neutron Science Center (LANSCE) accelerator at the Los Alamos National Laboratory. MCNPX simulations provide valuable information for the design of experiments in addition to their use in analysis of experimental to validate and improve the codes and databases. We propose a research project wherein UNLV students and faculty will contribute to these critical experiments by performing computational work using the latest versions of MCNPX and its associated data libraries. This research project will be conducted in close coordination with AAA leads and researchers in both experimental projects and code and database development.


Neutron flux; Neutrons; Particles (Nuclear physics); Radioactive wastes—Transmutation; Spallation (Nuclear physics); Spent reactor fuels

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Neutron flux; Particles (Nuclear physics); Radioactive wastes--Transmutation


Nuclear | Nuclear Engineering | Oil, Gas, and Energy

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106 KB