Sampling-based nuclear data uncertainty analysis in criticality and depletion calculations

Uncertainty and sensitivity analyses with respect to nuclear data are performed with criticality calculations for pin cells and a critical experiment, and with depletion calculations for a boiling water reactor fuel assembly. For this, the sampling-based tool XSUSA is employed together with the criticality and depletion sequences from the SCALE 6.1 code system. In the criticality calculations, uncertainties for multiplication factors, one-group cross sections, and the radial fission rate distribution are determined. When possible, comparisons are performed with results from the perturbation theory based TSUNAMI code; the agreement is excellent. In the depletion calculation, the uncertainty analysis refers to the multiplication factor and nuclide inventories. Special emphasis is put on performing group sensitivity analyses for the calculated results; thus, in addition to the output uncertainties, the main contributors to these uncertainties are evaluated by determining squared multiple correlation coefficients as importance indicators. For the critical assembly calculations, the impact of nuclear data uncertainties on the uncertainties of pin powers small. For nuclide concentrations in depleted fuel assemblies, the uncertainties can be significant. The main contributions to the actinide inventory uncertainties are due to neutron cross section uncertainties, whereas for fission products, neutron cross section uncertainties or fission yield uncertainties can be dominant.