Energies, Vol. 19, Pages 207: Spectrum-Dependent Burnable Poison Selection for Enhanced Safety and Neutronic Performance in an Epithermal Supercritical Carbon Dioxide-Cooled Reactor

Energies, Vol. 19, Pages 207: Spectrum-Dependent Burnable Poison Selection for Enhanced Safety and Neutronic Performance in an Epithermal Supercritical Carbon Dioxide-Cooled Reactor

Energies doi: 10.3390/en19010207

Authors:
Yiming Zhong
Jing Wen
Wenbin Wu
Naibin Jiang
Xiaoqi Zhou
Di Lu
Bin Zhang
Lianjie Wang

This study investigates the neutronic performance of burnable poisons (BPs) in an epithermal spectrum supercritical carbon dioxide (S-CO2)-cooled reactor. Twelve candidate BP materials are systematically evaluated, including rare-earth oxides (e.g., HfO2, Er2O3, Eu2O3, etc.) and boron-based compounds (B4C and PACS). The deterministic neutron transport code KYLIN-I with the ENDF/B VI 45-group cross-section library is employed for analysis. According to the calculation results, Eu2O3 effectively suppresses the initial kinf of the epithermal-spectrum fuel assembly to ~1.2 with a relatively low weight fraction (~2.6%) while maintaining a total temperature coefficient (TTC) lower than −1.4 pcm/K throughout the entire burnup period. HfO2 and Er2O3, at approximately 15% weight fraction, achieve TTC values better than −2 pcm/K. Furthermore, both Eu2O3 and HfO2 contribute to maintaining a low, stable power peaking factor (PPF) below 1.24 throughout the burnup process. This study provides a theoretical foundation and technical support for designing an efficient and safe S–CO2-cooled nuclear reactor. It highlights the importance of selecting BP materials that are well-adapted to the neutron spectrum and optimizing the fuel assembly configuration accordingly.