Fission Matrix in TDMCC Code for Loosely Coupled Systems Calculation

Abstract

In loosely coupled systems the criticality calculations using the traditional Monte Carlo power generation methods can lead to incorrect effective multiplication factor and neutron distribution functions, which is largely due to the steady-state neutron source in system. In reactor systems, the power generation method ensures the correct neutron source formation with a proper eigenfunction for any initial neutron distributions. A traditional power generation method does not guarantee the adequate source formation in loosely coupled systems even under very large calculation statistics. To count the neutron distribution functions in loosely coupled systems in TDMCC code is implemented algorithm based on fission matrix. Its capabilities are demonstrated to count the fission rate distributions in loosely coupled system such a slab with extended inhomogeneous fuel zones.