Progress in the Modeling of High Burnup Structure: Application of the TRANSURANUS//MFPR-F Coupling to the NRC-192 Studsvik LOCA TEST
Résumé
The MFPR-F (Module for Fission Product Release – France) code coupled with the TRANSURANUS fuel performance code was applied to the Studsvik NRC-192 Loss of Coolant Accident experiment on a high burnup UO2 fuel rod. The presented study, conducted in the framework of the R2CA project, focuses on the formation of the High-Burnup Structure during irradiation and on the fission gas release during the LOCA transient. MFPR-F code supplements TRANSURANUS code with a more in-depth description of the local microstructure in the UO2 matrix, allowing to predict the onset of fuel restructuring [1]. This modelling is used in the present study to calculate the width of the HBS zone in the fuel rod at the end of irradiation, which is found to be 400 µm. Regarding the LOCA transient, the MFPR-F model for fission gas release from the HBS pores, based on an empirical parameter related to the pore over-pressurization, predicts that a large part the gas is released for over-pressure ranging from 150 to 300 MPa.