Recent progresses of research on sensitivity and uncertainty analysis for reactor-physics calculation at XJTU

In this paper, the recent progresses of the researches on the sensitivity and uncertainty analysis for the reactor-physics calculations at XJTU have been presented. The widely applied deterministic method and statistical sampling method have been utilized and corresponding code programs have been developed. With the deterministic method, the Generalized Perturbation Theory (GPT) has been applied to perform the sensitivity and uncertainty analysis for the lattice calculations and burnup calculations, and corresponding home-developed codes named as NECP-COLEUS and NECP-SUNDEW respectively. For NECP-COLEUS, GPT is used to quantify the relative sensitivity coefficients of the important responses, including the eigenvalue and the few-group constants of the lattice calculations with respect to the cross sections; For NECP-SUNDEW, GPT is used to quantify the relative sensitivity coefficients of the important responses, including the eigenvalues and atomic densities with depletions of the burnup calculations to the cross sections. With the relative sensitivity coefficients of the important responses, both NECP-COLEUS and NECP-SUNDEW can quantify the uncertainties of corresponding responses introduced by the nuclear-data uncertainties. With the statistical sampling method (SSM), the code named NECP-UNICORN has been developed, and has the uncertainty-analysis capability for the lattice calculations and core simulations with depletions based on the 'two-step' scheme for the reactor-physics calculations. For NECP-UNICORN, the uncertainties of the eigenvalues, kinetic parameters, few-group constants and atomic densities with depletions for the lattice calculations can be quantified, and the uncertainties of the multiplication factor and power distributions for the core simulations can be quantified. As the numerical results presented, the application of NECP-COLEUS to perform sensitivity and uncertainty analysis for the eigenvalue and few-group constants of the lattice calculations, NECP-SUNDEW to perform sensitivity and uncertainty analysis for the eigenvalues and atomic densities with depletions of the burnup calculations and NECP-UNICORN to perform uncertainty analysis for the multiplication factor and power distributions to the steady-stated BEAVRS of the core simulations have been shown and analyzed in this paper. (authors)