γ辐照装置屏蔽方案评价

Evaluation of Shielding Scheme for Gamma Irradiation Facilities

依据《γ辐照装置的辐射防护与安全规范》,针对典型γ辐照装置升源状态不同辐射照射途经进行计算分析,以验证屏蔽设计的可靠性;对不同照射途经的辐射剂量率进行比较,提出优化屏蔽计算及设计建议。结果表明:(1)该γ辐照装置屏蔽设计方案满足辐射屏蔽要求;(2)屏蔽计算过程中,屏蔽体外天空反散射剂量率贡献大于直射辐射剂量率,迷道入口散射辐射剂量率贡献大于直射辐射剂量率;(3)考虑γ辐照装置工作负荷较大,并遵循辐射防护最优化原则:在屏蔽设计过程中应考虑一次散射照射剂量率贡献,必要时进行局部加厚处理,对于迷道散射设计次数应在5次以上,楼顶区域不建议布置长期人员居留场所。

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:①the design scheme of the typical gamma irradiation facilities meets the requirements of radiation shielding;②During 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;③Considering 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.