Analysis of the two-step source term calculation method with the high-fidelity source term calculation capability

摘要

The source term calculation capability is implemented in the high-fidelity neutronics code. With this high-fidelity tool, the accuracy of the two-step source term calculation method is analyzed in this work, including decay heat, the activation photon source term, and the neutron source term. The accuracy of NECP-X for the source term calculation is demonstrated through the comparison with SCALE6.1 and STREAM for a set of cases, and the results show good consistency between different codes. The analysis of the two-step source term calculation method is conducted by the control-variable method, and the approximations of generating cross-sections with the 2D lattice calculations and the homogenization process are analyzed for a full-core case. The numerical results show that approximations may result in some difference for the decay heat and the photon source results for the small core, and the difference is investigated with the high-fidelity source term calculation capability. (C) 2021 Elsevier Ltd. All rights reserved.