Behaviour of LWR Spent Fuel Rods During Storage and Under Accidental Impact Load Conditions

The scope of this contribution includes the assessment and evaluation of the structural behaviour of cladding and fuel under extreme transient load conditions encountered in hypothetic transport and handling accidents. The investigation focuses on a broad understanding of the failure (brittle rupture), fragmentation, and on the quantification of the fuel amount released per rod breakage corresponding to different burnup levels and fuel types. Additionally, the contribution aims at characterizing and understanding the evolution of the microstructure subjected to alpha decay and helium build up, in particular to verify extent and stability associated with defects saturation processes occurring at high damage level in the crystalline lattice, and determine if at very high accumulated dose level the decay damage and the radiogenic helium may affect the overall stability of the compound