摘要
•Influence of the reflector design applied different materials in NuScale SMR core are investigated.•Zircaloy baffle and BeO reflector are selected as the modified design according to the neutronic analysis results.•The neutron leakage distribution analysis reveals a higher reflector efficiency at the corner region of the core.•Modified reflector design increases 671 pcm reactivity to NuScale SMR core and flattens the core power distribution.
Neutron leakage in small modular reactors (SMRs) is more significant than in traditional reactors due to their smaller size, leading to increased radioactive waste production and reduced fuel efficiency. This study investigates optimized reflector designs to mitigate neutron leakage for SMRs using the NuScale SMR core as a demonstration case. Compared to commonly adopted stainless steel reflector, alternative reflector materials, including zircaloy, beryllium oxide (BeO) and graphite, are evaluated using MCNP 6.1 with the ENDF-VII cross-section library. Based on neutron attenuation and leakage current spectrum analysis, zircaloy baffle and BeO reinforcing reflector are selected. The leakage neutron distribution analysis reveals the best reflection efficiency for the reflector located at the corner region of the core. The modified reflector design proposed in this study increases NuScale SMR core reactivity by 671 pcm and effectively flattens the power distribution, demonstrating its promising potential to improve neutron economy of NuScale SMR.