Automatic modeling of PWR-core in the two-step reactor-core physics analysis code NECP-Bamboo

Abstract

In the field of PWR-core physics analysis, the dominant methodology remains two-step, which requires analysts to provide core structure and operating parameters, as well as a comprehensive understanding of the methodology for performing lattice and core calculations in multiple and sequential steps. This approach is inefficient and error-prone, resulting in a time-consuming modeling process. To address these challenges, we introduce Bamboo-Frame, an automatic modeling program within the NECP-Bamboo reactor-core physics analysis code that streamlines the modeling process by automating the identification of unique lattices, generating lattice and core input files, and performing lattice and core calculations using Bamboo-Lattice and Bamboo-Core/Transient, respectively. This approach lowers the analysis threshold, reduces workload, ensures parameter consistency, and enables users to switch modeling options with minimal adjustments. Verification and analysis based on the BEAVRS benchmark demonstrate the effectiveness of Bamboo-Frame, including a quantitative assessment of the radial nodal number in each assembly and spacer treatment in the axial direction. Results show that while 1 × 1 nodal modeling exhibits higher relative errors in radial and axial detector responses compared to 2 × 2 nodal modeling, they still align well with measurements. The analysis of spacer treatment indicates that modeling spacers solely in their respective layers have a more pronounced effect on axial profiles, including power and detector response, while modeling spacers along the entire axial direction also offers good overall agreement.