Evaluation on Creep properties of the modified HT9-W Fuel Rod According to the Variations of Temperature and Burnup

LMR fuel rod is irradiated under the high neutron flux and temperature operation conditions. Moreover as the core outlet temperature is increased from 530 .deg. C to 545 .deg. C based on KALIMER-600 design concepts, the integrity of the HT9 cladding having low long term creep strength at high temperature is not guaranteed. The parameters affected on fuel rod deformation are fission gas release, rod pressure build-up, FCMI, and cladding creep on at the high pressure and temperature under long term operation condition. One of the most important factors among these parameters is cladding creep phenomenon due to gas pressure build-up within the fuel rod. In-reactor thermal and irradiation creep characteristics for modified HT9-W were analyzed, and these characteristics were modeled for MACSIS in this study. The results were installed into MACSIS code, and the creep deformation for EBR-II fuel rod was evaluated by the MACSIS. It appears that the thermal creep resistance of the modified HT9-W is improved than HT9 and the design margin for metallic fuel rod is increased at high temperature