A review on the thermo-mechanical modeling needs in system codes

A review of the current thermomechanical needs along with a recommendation of the most urgent ones to be implemented in system codes are presented. It has been widely demonstrated that considering the fuel rods behavior in safety analyses including the fuel rod proper characterization of the pre-transient conditions could result in an important improvement in the accuracy of the simulation results for certain accidental sequences such as LOCAs. From an exhaustive review of the public literature, the thermomechanical phenomena involved in safety analyses are identified and, after reviewing the thermomechanical capabilities implemented in system codes, it is suggested that transient fission gas release, fuel axial relocation, cladding plastic deformation, cladding failure criteria, and flow blockage models should be implemented or improved in system codes to properly consider the impact of the conventional fuel rods behavior on safety analyses. In addition, the modeling needs of the Advanced Technology Fuel (ATF) materials cannot be forgotten. For that reason, the modeling needs regarding ATFs materials were assessed and it has been concluded that the main efforts should be focused on obtaining and implementing the correlations associated with the new materials, but also on identifying its new potential failure modes. Finally, further investigation is pointed out for establishing failure criteria and acceptance criteria for implementation of different ATF concepts in commercial reactors.

SÁNCHEZ TORRIJOS Jorge;  ARAGÓN Pau;  QUERAL C.;  FERIA F.;  SCHUBERT Arndt;  VAN UFFELEN Paul; 

2023-03-20

ELSEVIER SCIENCE SA

JRC130522

0029-5493 (online),   

https://www.sciencedirect.com/science/article/pii/S0029549323000924?via%3Dihub,    https://publications.jrc.ec.europa.eu/repository/handle/JRC130522,   

10.1016/j.nucengdes.2023.112243 (online),