Abstract
This paper presents the coupled RELAP5-3D and MCNP5 baseline PB-AHTR core model. The motivation of the study is to couple the thermal-hydraulics (T/H) with neutronics to investigate the feedback mechanism, coupled calculation viability and disparities of results between coupled and traditional approaches during steady state and transient scenarios in the PB-AHTR innovative core design, and also provide preliminary modeling approaches and results for further study. In order to analyze the steady state T/H behavior of the core and communicate with the neutronics calculation, a PB-AHTR MCNP5 core model, which achieved reliable steady-state, was developed. The power distribution of the PB-AHTR can be calculated by MCNP5 in fine enough resolution that it can be mapped to the RELAP5-3D mesh. Eventually, the preliminary results from the MCNP5 calculations during the transient are compared with those obtained from RELAP5-3D point kinetics model, indicating that the approach of comparing the reactivity evolution calculated by MCNP5 and RELAP5-3D during the transient is feasible. Further work will be focused on the systematic configuration of the RELAP5-3D model for more transient simulations.
