The concrete silo dry storage system, which has been in operation at the Wolsong NPP site since 1992, consists of a concrete structure, a steel liner plate in the inner space, and a fuel basket. The silo system’s concrete structure must maintain structural integrity as well as adequate radiation shielding performance against the high radioactivity of spent nuclear fuel stored inside the storage system. The concrete structure is directly exposed to the external climatic environment in the storage facility and can be expected to deteriorate over time owing to the heat of spent nuclear fuel, as well as particularly cracks in the concrete structure. These cracks may reduce the radiation shielding performance of the concrete structure, potentially exceeding the silo system’s allowable radiation dose rate limits. For specimens with the same composition and physical properties as silo’s concrete structures, cracks were forcibly generated and then irradiated to measure the change in radiation dose rate to examine the effect of cracks in concrete structures on radiation shielding performance, and in the current state, the silo system maintains radiation shielding performance.

I. Introduction
2. Irradiation Test for Concrete Crack
    2.1 Test Specimens
    2.2 Irradiation Test
3. Dose Rate Evaluation for Cracks
4. Conclusion
Conflict of Interest
Acknowledgements
REFERENCES

• Donghee Lee(Central Research Institute, Korea Hydro & Nuclear Power Co. Ltd., 70, Yuseong-daero 1312beongil, Yuseong-gu, Daejeon 34101, Republic of Korea)
• Sunghwan Chung(Central Research Institute, Korea Hydro & Nuclear Power Co. Ltd., 70, Yuseong-daero 1312beongil, Yuseong-gu, Daejeon 34101, Republic of Korea)
• Taehyung Na(Central Research Institute, Korea Hydro & Nuclear Power Co. Ltd., 70, Yuseong-daero 1312beongil, Yuseong-gu, Daejeon 34101, Republic of Korea) Corresponding author