Preliminary assessment of lattice physics capabilities for VHTR analysis

The very high-temperature gas-cooled reactor (VHTR) is an important element in the USDOE program to revitalize nuclear power in the U.S. suite of energy generation options. It is currently planned to build the first VHTR, called the Next Generation Nuclear Planat (NGNP), in the next ten years. To have confidence in the NGNP design, the computation tools used for the design studies need to be validated. As a first step in this validation effort, a preliminary assesment of lattice physics capabilities has been performed for the prismatic fuel assembly designs of the NGNP and GT-MHR Minor Actinide Burner (GT/AD-MHR). Both designs use the same fuel block dimensions and structural materials, but different fuel particle dimensions and compositions. UC0.5O1.5 fuel particle with fuel kernel diameter of 350 μm is used for the NGNP design, and the UO2 and (TRU)O1.7 fuel forms with kernel size of 200 μm are considered for the GT/AD-MHR designs