Verification and validation of new unmodified SCALE PWR lattice templates

The goal of this analysis was to determine the effectiveness of using pre-developed, unmodified templates to create cross-section libraries using a full reactor physics simulation. Those cross-section libraries can then be interpolated to problem-specific conditions (e.g., the burnup, enrichment, and void fraction specific to the problem) in order to perform rapid depletion calculations without the need to re-run time-intensive transports calculations. However, unlike in typical benchmark studies the templates were modified to a minimal degree, much as what would be seen in practical application. The goal of this study is not to test the full capabilities of the SCALE system. Using the unmodified templates in situations without advanced modeling requirements, such as burnable absorbers, the templates performed with a sufficient degree of accuracy, often producing plutonium isotopics within 10% of reported measurements. However, accuracy is lost when not accounting for special modeling features, such as a pin located on the edge of an assembly. This errors of 15-20% for plutonium isotopics, with significant changes in accuracy for ²³⁸Pu. Additionally, Multi-Variate Analysis techniques such as Principal Component Analysis (PCA) and Partial Least Squares (PLS) regression is applied to existing radiochemical assay data to determine relationships between nuclides and burnup. Using PLS it is possible to determine the linear variation in the assay data that is due to the linear variation in burnup. Multivariate techniques indicate that 85% of the linear variation in the isotopics is due to the variation in burnup, however, further research is required to determine the goodness of fit of the model.