FCVS作動下における流体振動の基礎研究

抄録

The 2011 Great East Japan Earthquake and Tsunami caused a severe accident at the Fukushima Daiichi Nuclear Power Plants, which resulted in the loss of all power and cooling functions. During this accident, a wetwell vent was used to vent gases out of the reactor containment vessel to prevent containment failure, but the pool scrubbing effect was less than expected and a large amount of radioactive materials were released into the environment. Learning from this accident, the Nuclear Regulation Authority (NRA) mandated the installation of a filtered containment venting system (FCVS). However, when this system is used, condensation due to contact between steam and pool water, resulting in fluid vibration. In this study, the effects of nozzle orientation, air flow rate, pool water temperature, and steam mass flow rate on fluid oscillations were investigated by measuring pressure transient with a pressure sensor and photographing the gas-liquid interface with a high-speed camera, assuming FCVS operating conditions. This paper reports the results obtained from the experiments.