反应堆卸料燃料组件吊运跌落事故辐射安全分析

Radiation Safety Analyses of Whole Basket Fuel Assembly Falling Accidents during Reactor Discharging

在反应堆卸料过程中,燃料组件吊运是关键操作之一,由于在燃料组件吊运时发生跌落事故的后果较为严重,需要预先对该事故进行详细分析,评价事故对工作人员、公众及环境的影响。本文从事故起因、事故进程、事故缓解措施、事故处理程序及事故后果等方面对燃料组件吊运跌落事故进行了描述、分析和评价。从事故分析可见,发生燃料组件吊运跌落事故时,由于^(85)Kr的逸出而造成工作人员受到浸没外照射的剂量不超过1.28×10^(-1)m Sv。工作人员对事故进行处理而受照的剂量最大为15 m Sv。从环境影响评价可知,事故致使厂址N方向距离厂址边界约1.5 km处村庄公众接受的个人有效剂量最大,为2.56×10^(-6)m Sv,10 km范围内公众集体有效剂量为3.75×10-2人·m Sv。

During the whole period of reactor discharging,transporting the fuel assemblies by crane is a key operation. Because the consequences would be very serious when the whole basket of fuel assemblies fall while being lifted,it is necessary to progress a detailed analysis and evaluation of the accident in advance to evaluate the influence to staff,the public and environment. This paper provides the descriptions,analyses and evaluations of the falling accidents in the perspective of causes,progresses,mitigating measures,handling procedures and consequences. From the analysis of the accident,staff would receive submerged external exposure dose of less than 1. 28 × 10^-1 mSv from diffused ^85 Kr during a falling accident,and they would get the dose of 15 mSv for processing the accident. For the public,the maximum individual effective dose is 2. 56 × 10^-6 mSv,which appears in the village of about 1. 5 km away from the site in the N direction. The collective effective dose of the whole public at a range of 10 km is 3. 75 × 10^-2 mSv.