The effects of pile irradiations on the physical properties and corrosion resistance of U-- Mo, U-- Nb; and U--Si alloys are reported. The dimensional stability under irradiation of the gamma phase U-- Mo and U-- Nb alloys is excellent; however, an isotropic volume increase of 4 to 6% per wt.% burnup may limit the ultimate fuel element life. Corrosion resistance of the gamma-phase alloys appesrs to be improved when subjected to s neutron field; this is attributed to an irrsdiation induced stabilization of the gamma phases. The U/ sub 3/Si alloy, on the other hand, suffered severe deterioration, particularly of corrosion resistance. Changes in electrical resistivity, hardness, mechanical properties, and crystal structure are presented and the mechanisms producing the observed changes discussed.

The effects of pile irradiations on the physical properties and corrosion resistance of U-- Mo, U-- Nb; and U--Si alloys are reported. The dimensional stability under irradiation of the gamma phase U-- Mo and U-- Nb alloys is excellent; however, an isotropic volume increase of 4 to 6% per wt.% burnup may limit the ultimate fuel element life. Corrosion resistance of the gamma-phase alloys appesrs to be improved when subjected to s neutron field; this is attributed to an irrsdiation induced stabilization of the gamma phases. The U/ sub 3/Si alloy, on the other hand, suffered severe deterioration, particularly of corrosion resistance. Changes in electrical resistivity, hardness, mechanical properties, and crystal structure are presented and the mechanisms producing the observed changes discussed. (auth).