Assessment of dry storage performance of spent LWR fuel assemblies with increasing burnup

摘要

Although the safety of a dry long-term spent fuel store is scarcely influenced if a few fuel rods start of leak during extened storage-since all confinement ystems are designed to retain gaseous activity safely-it is a very conservative safety goal to avoid the occurrence of systematic rod defects. To assess the extended storage performance of a spent fuel assembly (FA), the experimence can be collated into 3 storage models: I-fast rate of temperature decrease #delta# (max) >= #delta# >=300 deg C , II-medium rae of decrease for the fuel rod dry storage temperature 300 deg C > #delta# >= 200 deg C III-slow to negligible rate of temperature decrease for #delta# < 200 deg C . Model I is typical for early interim storage, mode III covers extremely long-term storage.