Improving source convergence diagnostics sensitivity using the complex components of Fourier fundamental mode

Abstract Previous works have demonstrated that the Fourier fundamental mode coefficient (FFMC) is a potential fission source convergence indicator for Monte Carlo k -eigenvalue calculations. Unlike conventional Shannon entropy indicator, it requires no spatial meshing, and its computation computationally inexpensive. However, we found FFMC less sensitive to involving near symmetrical distributions. To rectify problem, focus on analysis of FFMC’s components (the real imaginary parts) simple geometry problem full reactor core problem. The usage more conservative compared original method as supported by improved results detection.