Creation of the VADER Code in SCALE

VADER (Validation Analysis Data Evaluation Resource) is a new module in SCALE 6.3 that has been derived from the legacy USLSTATS program. VADER is a tool that allows the determination of bias and bias uncertainty for criticality safety computational methods. VADER has been completely written in C++ using modern coding practice and standards. It has been moved to be part of the SCALE code package and is run through the normal SCALE executables. To support the VADER methods, large updates were made to the statistical capabilities of SCALE. Interfaces to known statistical distributions were added and many of the statistical calculations required for VADER were made available to all SCALE sequences. In addition to being able to process legacy USLSTATS inputs, VADER adds support for the single sided tolerance band method (from NUREG/CR-6698) as well as two non-trending methods: the “historical” nonparametric and parametric methods, also as described in NUREG/CR-6698. VADER also includes several new tests for normality in addition to adding user control options on the original chi-squared normality test. A new t-test for the statistical significance of the trend is included. Future work includes expanding the available suite of normality tests to include the Anderson-Darling test and the Shapiro-Wilks test. VADER has also been integrated into the Fulcrum GUI used by SCALE. This allows VADER to benefit from the auto-complete, templating, and input validation features offered by Fulcrum. In addition, Fulcrum can plot the results given by VADER and the plot files have been expanded to include the new methods available in VADER.