Radiation safety analysis of emergency repair personnel in the reactor cabin under the natural circulation condition of the reactor

Objective Radiation safety of emergency repair personnel in the reactor cabin under the natural circulation condition of the reactor is studied, the radiation protection method of emergency repair personnel in the reactor cabin is described, which provides a theoretical reference for personnel radiation protection and emergency repair time control. Methods The radiation was simulated by the Monte Carlo method for emergency repair personnel in the reactor cabin under the natural circulation condition of the reactor, and the radiation was also analyzed with the radiation data measured by experiments in the reactor cabin under the natural circulation condition of the reactor. Results The neutron dose of external irradiation about reactor simulated computation was 140 µSv/h, and gamma radiation dose rate was 48 µSv/h. By experiment and calculation, the effective dose received by emergency repair personnel in the 30-minutein the reactor cabin was 2.2 mSv. Conclusions Under the natural circulation condition of the reactor, the gamma radiation is harmful to emergency repair personnel, but the focus of protection is different locations for maintenance. It’s safe for emergency personnel to repair the reactor in 30 minutes in turn, wearing the respirators. 摘要： 目的 开展对反应堆自然循环工况下抢修人员辐射安全研宄, 阐述反应堆舱应急抢修人员辐射防护方法, 为应 急抢修人员辐射防护和抢修时间控制提供理论参考。 方法 针对反应堆自然循环工况下抢修人员辐射情况, 利用蒙 特卡罗方法进行模拟计算, 并结合自然循环工况下反应堆舱实验测量的辐射数据进行验证分析。 结果 反应堆外照 射模拟计算中子剂量率约为 140 µSv/h, γ 辐射剂量率为 48 µSv/h, 实验测量计算抢修人员在 30 min 堆舱内受到的有效 剂量为 2.2 mSv。 结论 自然循环功率下进堆舱抢修, γ 辐射对抢修人员危害大, 但在不同的位置维修, 防护重点又有 不同;佩戴呼吸器, 30 min 轮流抢修的方式, 对抢修人员是安全的。