中放废物坑扩孔操作的石英砂屏蔽实践

A shielding practice with silica sands for an intermediate level radioactive waste pit in order to enlarge the opening

为了回取小坑口废物坑中的废物,利用了石英砂的流动性和吸尘器的抽吸功能,用石英砂屏蔽表面辐射水平为4.28Gy/h的坑内中放废物,将坑口辐射水平降至4.49μGy/h后,安全地实现了扩孔操作,实施屏蔽和拆除屏蔽过程都实现了远距离操作,极大降低了人员所受剂量,屏蔽实施与拆除操作人员的集体剂量仅为0.45人·mSv。

In order to retrieve the waste from a waste pit with small opening,the silica sands packaged in a canvas bag was used to shield the intermediate level waste( ILW). The shielding depth was calculated with QAD-CG,and the filling and retrieve of silica sands was well prepared and practiced. The dose rate at the opening was reduced from 4.28 Gy/h to 4.49 μGy/h. The waste retrieve work went on smoothly. The personnel collective dose to set and dismantle the silica sands shielding facility is 0.45 men·m Sv in total.