Irradiation of U 3Si-based compounds in the high-voltage electron microscope

Abstract

U 3Si and U-3.5 wt% Si-1.5 wt% Al have been irradiated in a high-voltage electron microscope (HVEM) at 500–1180 keV and 300–660 K. The creation of ‘black spot’ damage and removal of deformation twins are observed. Defects about 10 nm diameter averaging 4 × 10 21 m −3 are seen only in samples pre-injected with 10 −5 atomic fraction argon and are tentatively identified as voids. The atomic displacement rate during HVEM irradiation of U 3Si-based compounds is about two orders of magnitude higher than that for fuel at power reactor ratings. It is inferred that displacement of silicon, and possible uranium, atoms in U 3Si-based compounds occurred in the HVEM at accelerating voltages in the range 700–1180keV.