Hybrid depletion method for the light water reactor analysis

Monte Carlo (MC) depletion has big obstacle in the full-scale reactor core analysis. It requires a memory usage of terabyte unit. It is thus not allowed to compute with contemporary computer resource. Computation time is another big obstacle in that full-scale reactor core analysis such as BEAVRS 3D core problem. Hybrid depletion method has been introduced by combination in MC code and the Deterministic code. In this work, two codes, MCS and STREAM, are used in implementation of Hybrid method. STREAM code has high accuracy in production of the effective cross-section with pin-based pointwise energy slowing-down method. The hybrid depletion method uses the multi-group flux by tally from the MC code and effective cross-section from the STREAM code. It reduces significantly the memory usage because the massive tallies during MC transport calculation are not needed anymore. It also takes advantage of the reduction of portion of the computation time. In current work, it shows that 10% less computational time and less 30 times of the memory usage are required in the Hybrid depletion method compared to conventional MC depletion method. (authors)