The history-partitioning method for multigroup stochastic cross section generation

The method is demonstrated using a highly heterogeneous VHTR pin cell model. Homogenized cross sections are generated for a fuel region consisting of encapsulated fuel particles dispersed in a graphite matrix, placed back into the pin cell problem, and compared to the original continuous energy heterogeneous model. Results show eigenvalue agreement of approximately 100 pcm, which is within the estimated uncertainty range of the multigroup data.