Three sees of beryllia-coated, fuelled beryllia spheres were made for fission product release testing in a sweep capsule irradiation rig Results of various pre-irradiation tests are presented and discussed, and a summary of fission gas release results is included, Gas release rates were expected to vary inversely as the beryllia density However, the release rate was lowest for the loading with an intermediate density and was highest for that with the highest density One or more of several structural factors may have changed the behaviour from that expected
