Monte Carlo simulation on neutron irradiation damage of solid tritium breeder for fusion application

The test blanket module (TBM) with function of tritium production and energy extraction is one of the most important components for a fusion reactor. Lithium-containing ceramics have been recognized as attractive tritium breeding materials for fusion reactor blankets based on their favorable chemical stability, appropriate thermo-mechanical properties, good tritium release performance and application at higher operating temperature, etc. The helium cooled ceramic breeding (HCCB) TBM is selected in Chinese (CN) TBM design. And their irradiation damage behaviors under fusion neutron environment are necessary to be evaluated to support the design criteria for CN HCCB TBM. In this study, the neutron irradiation displacement damage and the transmutation gas damage of Li₄SiO₄ and Li₂TiO₃ have been carried out with Monte Carlo simulation. The results demonstrated that more serious damage characteristics, such as more damage dose, larger defect production cross-section in high ⁶Li enrichment and higher transmutation gas production rate, have been found in Li₄SiO₄ than that in Li₂TiO3 at the same service time. However, the vacancy damage induced by transmutation gas of Li₂TiO₃ is more severe than that of Li₄SiO₄, and helium induced damage is stronger than that of tritium for both two lithium ceramic breeders. (authors)