Development of cross-section data set repository and interpolation code system, LOCUS

The cross-section data library and its interpolation code, LOCUS, is being developed for the acceleration of cross-section data generation for use in ANC9 core calculations. The initial version of LOCUS targets a range of applicability for widely used Westinghouse PWR fuel types using standard UO₂ fuel and its associated burnable poison types (i.e. Integral Fuel Burnable Absorber (IFBA), Wet Annular Burnable Absorber (WABA), and any combination thereof). The interpolation parameters are U²³⁵ fuel enrichment, fuel pellet theoretical density and IFBA thickness. These parameters are individually investigated to determine their interdependence and to evaluate the order and increment size for each parameter. The linear interpolation in pellet density and the quadratic interpolation in enrichment and IFBA thickness showed good agreements as compared to the reference solutions. These three parameters are interpolated at the same time by tri-linear/quadratic Lagrange interpolation to generate a cross-section data set at target enrichment, pellet density and IFBA thickness. ANC9 calculation results by the LOCUS interpolated cross-section data set are compared with that by the reference cross-section set. They agreed very well in k-infinity, pin power, control rod worth, etc. The cross-section data sets generated by LOCUS are also applied to Reload Safety Analysis Checklist (RSAC) calculations in full-core geometry and compared with reference solutions obtained by non-interpolated cross-section data sets. All calculation errors are very small and negligible. These results demonstrate that LOCUS can supply the cross-section data sets consistent with the current non-interpolated cross-section data sets. (authors)