高除染性フィルターベントシステムにおける二相流安定化

抄録

Fukushima Daiichi NPP accident would be terminated, if sufficient accident countermeasures, such as water proof door, mobile power, etc. In case of Europe, it had already installed the heat removal system and filtered containment venting system (FCVS) from the lessons of TMI and Chernobyl Accidents. The new regulatory standard, the filtered vent system (FCVS) should be installed, and prevent the radioactive material in case of the severe accident and the overpressure breakage prevention of a primary containment vessel (PCV) and also stabilize the FCVS. The authors examined the severe accident process in the 2^nd unit of Fukushima Daiichi NPS, and found the vent by FCVS should be done before water injection into the core. By conducting two-phase flow visualization test, the authors also pointed out the necessity of stabilization in the scrubbing pool. TRAC code analysis was also conducted to clarify the mechanism of the geysering and stabilized by using an orifice plate to pressurize the scrubbing pool.