Fission Fragment Damage in Nonfissionable Thin Films

Fission fragment damage in thin films of nonfissionable materials was studied using Qansmission electron microscopic and shadowing techniques. Multilayered films containing regions free from UO/sub 2/ were prepared by evaporating or sputtering the material onto a carbon substrate, spraying with a suspension of polystyrene latex spheres, and shadow coating with UC/sub 2/ at an angle of 15 deg ; the regions behind the spheres contain no fissionable UO/sub 2/. Multilayered films consisting of UO/sub 2/-Pt-C and UO/sub 2/-ZrO/sub 2/-C layers were irradiated to a thermal neutron exposure of 2 x 10/sub 16/ nvt and then examined. For UC/sub 2/- Pt - C, perforated ridges were observed for the tracks in the UO/sub 2/-free regions. For UO/sub 2/ZrO/sub 2/-C, the tracks are more uriform and have a high electron transmission, but shadowing revealed nodular imperfections superimposed on the tracks. (D.L.C.)