Metallic Fuel Performance Benchmarks for Versatile Test Reactor Applications

The U.S. Department of Energy Office of Nuclear Energy’s Versatile Test Reactor (VTR) project is designing a new fast-spectrum test reactor. The VTR reference driver fuel design is sodium-bonded U-20Pu-10Zr (wt%) metallic fuel and HT-9 cladding. The BISON fuel performance code is being used to model the VTR driver fuel pin to evaluate the effects of differences between its design and the legacy designs that preceded it. This work summarizes ongoing efforts at Oak Ridge National Laboratory to benchmark BISON for VTR driver fuel analyses, including establishing metallic fuel performance code requirements for VTR applications and benchmarking BISON for VTR driver fuel analyses. Integral fuel pin predictions are compared to legacy calculations and post-irradiation examination data for 261 fuel pins irradiated at Experimental Breeder Reactor II and the Fast Flux Test Facility. The BISON predictions exhibit trends that are generally consistent with the legacy data. Burnup and temperature predictions were found to be more accurate than mechanical predictions such as radial cladding dilation, axial fuel elongation, and plenum pressure. Likely sources of error were identified for evaluation in future work.