Study on the Injection Region for Pool Scrubbing

The wet type CFVSs are mainly composed of a liquid pool and filters. Gases of high temperature and pressure are injected into the liquid pool by nozzles from a containment when the CFVS starts to operate in a severe accident. According to previous studies, pool scrubbing for fission products occurs effectively when gases enter the pool at a very high velocity. In other words, the velocity of injection gas is a key parameter in the injection region for pool scrubbing. Therefore, in this study, the criteria of the injection regime were examined and a preliminary review was performed for the injection zone with a hypothetical scenario case. In order to study hydraulic conditions at the injection zone for pool scrubbing, the Weber numbers of the CFVS pool injection region were calculated under a hypothetical case. During the accident, all Weber numbers indicated that the injection zone of the pool was at the jet regime (We ≥ 10⁵) when the CFVS was operated. This means effective decontamination is possible during the entire period of the accident