Changes to Sustainability of Uranium Carbide Fuel for a Long-Burn Fast Reactor Core

Advanced reactor concepts such as Generation-IV (Gen-IV) have been studied to fulfill the ambitious long term goals of developing a safe, sustainable, reliable, proliferation-resistant and economic nuclear energy system. The gas-cooled fast reactor (GFR) is a Gen-IV candidate for which a carbide fuel (UC, (U,Pu)C, ThC) has desirable properties in a fuel system using ceramic (SiC) cladding. This study reviews advanced fuel concepts and associated fabrication methods for a GFR, followed by available carbide fuel property data, update of fuel performance code, and assessment of the fuel performance analysis model based on irradiation test results in the Fast Flux Test Facility. The purpose of this study is to develop a fuel performance code for the design and analysis of carbide fuel and to verify the implementation of fuel property models using earlier fuel irradiation tests jointly conducted by US and Switzerland. The comparison of carbide fuel simulation results to the experimental data shows differences in the prediction of fuel temperature and swelling. Considering the limitation and uncertainty of the existing material property data, the results obtained from the updated fuel performance code indicate that more work is required to adjust and update some of the carbide fuel material property models. In the future, the coolant model will also be updated for the flexibility of code application to various advanced fuel analyses. In the long term, the code will be used for the evaluation of advanced carbide fuel with ceramic cladding and the simulation of carbide fuel irradiation tests.