Low temperature creep of used nuclear fuel during long term dry storage

The evaluation of the long term clad creep behavior of used nuclear fuel (UNF) in dry storage is being performed under the Integrated Research Project (ERP) "Fuel Aging in Storage and Transportation," (FAST) which includes six university partners with multiple investigators per university, as well as supporting advisors from Savanna River National Laboratory and Pacific Northwest National Laboratory. This effort is just in the beginning stages of its evaluation of data and model development, such that the results provided in this paper are of a preliminary nature. The evaluation of creep will characterize the low-temperature low-stress mechanisms relevant to dry storage. The major objectives are (1) to obtain data using highly oxidized/hydrided tubing under relevant stresses and temperatures, (2) to characterize and translate that data for development of a low temperature creep model input to FRAPCON and other codes to predict UNF behavior during dry storage, and (3) to formulate atomistic simulations to develop a better understanding of the long term creep behavior with emphasis on effects of oxygen and hydrogen as well as neutron irradiation in order to enable extrapolation of the models to long term storage.