Review and selection of state-of-the-art models for advanced fuel performance analysis

The deliverable D4.2 encompasses a thorough review and of behavioural models for accurate fuel performance calculations. POLIMI is responsible for review and select fission gas behavioural models in SCIANTIX, an, open-source code for fission gas behaviour, which is coupled with OFFBEAT. The focus is on advancing high-burnup structure models, the modelling of chromia-doped fuels and athermal fission gas release. EPFL reviewed and selected models relevant to the OperaHPC project objectives, addressing key gaps in OFFBEAT’s capabilities. In particular, EPFL focused on RIA, implementing anisotropic viscoplasticity and a failure criterion for hydrided cladding; LOCA, introducing large-strain and high-temperature models; and contact modelling, developing an implicit algorithm for pellet-to-pellet and pellet-to-cladding interactions during PCMI. Plans have also been made to develop a 3D gap heat transfer model to assess the impact of traditional 1D heat conductance models in wide-gap conditions such as during cladding ballooning. PSI undertakes the development of models for cladding oxidation, hydrogen transport, and geometric imperfections. Additionally, PSI conducted a comprehensive review of multidimensional macroscopic fuel behaviour models in international codes such as ALCYONE (CEA), BISON (INL), DIONISIO (CNEA), and Falcon (EPRI). This review identified key models for implementation in OFFBEAT to enhance its predictive capabilities for fuel performance analysis.