松散污染物雾化固定模拟试验研究

Experimental study on encapsulating the loose contamination by atomizing process

针对核工业厂房内的放射性松散污染物,运用超声雾化技术,将固定剂在无人员进入的情况下通入模拟设备室的试验间,采用碳酸钙粉末作为模拟物,模拟松散污染物并进行固定试验。使用风机沿平行地面方向对固定后的松散污染物进行扰动,考察不同松散污染物沉积量和不同固定剂用量对扰动后再悬浮因子的影响和扰动前后气溶胶粒径分布的变化。结果表明,扰动后,再悬浮因子随着松散污染物沉积量增大;提高固定剂通入量可增强固定效果,有效降低再悬浮因子;达到一定量后,继续增加固定剂通入量作用微小。对该模拟粉尘,每1 mg·cm?2的松散污染物需要通入0.57 kg·m?2的固定剂。根据松散污染物量,使用适量的固定剂进行雾化固定,可以有效固定松散污染物,显著降低松散污染物的再悬浮因子,降低工作人员受照的风险。

The ultrasonic atomizing technique was used to add fixative to the analog device without human intervention. The simulation experiment on loose contamination was conducted by choosing the calcium carbonate powder as analog solid agent. And then, the encapsulated loose contamination was disturbed by fan along the direction parallel to ground to investigate the amount of loose contamination as well as the fixative vs. the re-suspension factor and particle size distribution. The results showed that the loose contamination deposited amount had a positive correlation on the re-suspension factor. The re-suspension factor decreased with the increasing amounts of fixative. When reaching a certain value, the effects were tiny by increasing the amount of fixative. For 1mg·cm-2 calcium carbonate powder, 0.57 kg·m-2 fixative was necessary. According to the amount of loose contamination, an appropriate amount of fixing agent can effectively fix the loose contaminants and significantly reduce the re-suspension factor, which can reduce workers＇ exposure risk to radiation.