TRANSURANUS simulation of WWER cladding creep under dry storage conditions

Limited cladding creep deformation is one of the main safety criteria for the long term storage of the spent nuclear fuel. To keep the fuel rod hermetically closed the safety limit of the permanent hoop strain is generally 1%. In order to check the fulfilment of this criterion for VVER fuel rods in Modular Vault Dry Storage (MVDS) facility deterministic and probabilistic analyses were performed by the TRANSURANUS fuel code. This code provides the unique possibility of the consistent simulation of the fuel performance during both the normal irradiation in the reactor and the 50 year storage. The question of the minimum necessary period of the spent fuel rods' cooling in the at-reactor (AR) water-filled pool was also investigated in the study. According to the performed computations the permanent deformation of the cladding in the MVDS strongly depends on the wet storage period. (author)