Study of the manufacturing process of gamma-U7%wtMo dispersion fuel plates

Abstract

The search for new materials for nuclear fuels has been developed over the last 50 years, with the main aim of increasing the fuel efficiency during the operation of the reactors. The need to increase the uranium density in fuels to compensate the reduction of enrichment proposes that the UMo alloy is one of the materials that presents better characteristics to be used as fuel: molybdenum is a material that retains the gamma phase of the uranium in low concentrations, which is the only stable phase of uranium under the irradiation conditions, besides having low thermal neutron absorption. Although more advanced studies already provide information on the interaction between UMo and the Al matrix, we still need to study how this material behaves during all processing steps for fuel fabrication. The present work has the objective of to deepen the technological knowledge about the stages of production of dispersion type nuclear fuel, including the comminution process of the UMo alloy. The alloy pulverization made by the hydriding-grinding-dehydriding technique still reveals a large number of unknowns in the process variables. Knowing some parameters already existent in the literature, it is possible to discuss the behavior of the hydriding process and envision improvements to optimize it as well as make it reproducible. Subsequent manufacturing steps for briquette and rolling were performed according to IPEN's expertise and the results indicate that the UMo alloy is mechanically doable and may prove to be a substitute fuel for the current U3Si2 with a higher uranium density.