Evaluation of Carbide Fuel Property and Model Using Measurement Data from Early Experiments

The performance of uranium-plutonium mixed carbide fuel was analyzed based on experimental data produced from the Japan Research Reactor No. 2, the Japan Materials Testing Reactor, and the Fast Flux Test Facility irradiation tests during 1983 to 1992. The analysis includes a review of earlier fuel irradiation test results, material property data, and physics models, and a simulation by a finite element method fuel performance code FEMAXI-6GA to predict the historic results. The simulation results were compared to the measured fission gas release, fuel swelling, and dimensional change of the cladding. The simulation results are reasonably consistent with the measurement. However, a few differences between the simulations and measurements were encountered, which are attributed to the lack of detailed experimental conditions, characteristics of fuel materials, material property data, and physics models. Based on sensitivity analyses of the results to experimental conditions and material property data, it is recommended to develop an experimental plan for the systematic measurements of thermal conductivity, including the effect of porosity, impurities, and stoichiometry, fission gas diffusion, and irradiation-induced swelling and densification, supplemented by advanced modeling and simulation techniques to support advanced fuel development in a cost-effective way.