Abstract: Based on 《Radiation protection and safety regulations for Gamma irradiation facilities》, a detailed quantitative calculation and analysis were carried out for the different radiation paths of the typical gamma irradiation facilities in the source up-state, in order to verify the reliability of the shield design. Radiation dose rates of different radiation paths were compared, and the optimization of the shield calculation and design suggestions were put forward. The results show that: ① the design scheme of the typical gamma irradiation facilities meets the requirements of radiation shielding; ② During the shielding calculation, the contribution of sky back scattering dose rate outside the shielding is greater than that of direct radiation, and the contribution of scattered radiation dose rate at the entrance of the labyrinth is greater than that of direct radiation; ③ Considering the large work load at gamma irradiation facilities, and follow the optimization principle of radiation protection: in the shielding design process the contribution of a scattering radiation dose rate should be considered; and if necessary, some local thickening should be added; for the scattering design the scattering number should be more than 5 times; the roof area is not recommended for long term personnel residencet.

Key words: Gamma irradiation facilities, Shielding computation, Radiation protection