Monte Carlo-based simulation on radiation shielding verification for a dry spent fuel storage model

Abstract Background: Radiation shielding performance and criticality safety play important roles in the safety performance of dry fuel container. Purpose: The purpose is to develop a type of dry spent fuel storage CHN-24 container, which can contain burn-up 45 GWD/MTU spent fuel totaled 24 groups. Methods: Radiation shielding performance and criticality safety were checked and validated using Monte Carlo method to establish a radiation-dose rate-calculation model for the CHN-24 container. Results: The fuel k_eff in container under normal storage condition was 0.283, which increased gradually with the water level and reached the maximum 0.706 at the highest level. The dose equivalent rates decreased with the increasing flooding, and under normal condition, the dose rates at the surface of the container and at a distance of 1 m from the surface were 0.42 mSv·h^-1 and 0.08 mSv·h^-1, respectively, which conforms to the radiation safety standards of International Atomic Energy Agency (IAEA). Conclusion: The results showed that Monte Carlo method can be applied to verify the critical security and radiation shielding performance of dry spent fuel container. (authors)