Aspect of UO2 fuel chemistry at high burnup

It is very important to investigate fuel chemistry on the performance of uranium dioxide fuel and its cladding in connection with high burnup nuclear fuel research and development. This work could lead to some illuminating conclusions for specific burnup induced phenomena in the uranium dioxide fuel at high burnup, based-on a large number of results published in the open literature or accumulated through international communications; i) the cladding behavior could lead to operation restrictions during load follow at high burnup, ii) the burnup induced enhancement of fission product gas release could be interpreted either as an increase in the fission product diffusion properties resulting from the fuel hyperstoichiometry, or as a result of the temperature increase resulting from a degradation of thermal conductivity, or as a combination of these two effects