Monte Carlo response matrix method

The response matrix method (RMM) has been used in nuclear reactor analysis for many years. It consists of two distinct calculational steps - the local calculation to compute the response matrices and the global calculation to compute the global partial current and flux distributions. The Monte Carlo method (MCM) has been used previously to compute the response matrices in the local calculation but has not been utilized to perform the global calculation. In this work, a new method, the Monte Carlo response matrix method (MCRMM), implements the MCM for both the local and global calculations. The MCRMM has been developed and tested. It retains the well-known advantage of the RMM to eliminate unneeded calculations at the lower level. That is, once the response matrices (pdf's and track-length tables in the MCRMM) are generated from the local calculations, one may solve problems in any combination of cells without redoing the local calculations. In addition, a fast discrete sampling method has been applied in the global calculation. Finally, a Dirichlet distribution sampler has been implemented in order to do a sensitivity analysis to evaluate the uncertainties due to the generated response pdf's