The use of U3Si2 dispersed in aluminum in plate-type fuel elements for research and test reactors

A high-density fuel based on U3Si2 dispersed in aluminum has been developed and tested for use in converting plate-type research and test reactors from the use of highly enriched uranium to the use of low-enriched uranium. Results of preirradiation testing and the irradiation and postirradiation examination of miniature fuel plates and full-sized fuel elements are summarized. Swelling of the U3Si2 fuel particles is a linear function of the fission density in the particle to well beyond the fission density achievable in low-enriched fuels. U3Si2 particle swelling rate is approximately the same as that of the commonly used UAl/sub x/ fuel particle. The presence of minor amounts of U3Si or uranium solid solution in the fuel result in greater, but still acceptable, fuel swelling. Blister threshold temperatures are at least as high as those of currently used fuels. An exothermic reaction occurs near the aluminum melting temperature, but the measured energy releases were low enough not to substantially worsen the consequences of an accident. U3Si2-aluminum dispersion fuel with uranium densities up to at least 4.8 Mg/m3 is a suitable LEU fuel for typical plate-type research and test reactors. 42 refs., 28 figs., 7 tabs