福島第一原子力発電所(1F)の 2 号機 RCIC タービン内二相流挙動に関する基礎的研究

抄録

A reactor core isolation cooling (RCIC) system of the Fukushima Dai-ichi Nuclear Power Plant Unit 2 (1F2) was continued to operate even after the loss of power supply. However, the fact that water injection by the RCIC system is continued was still unknown. On the other hand, from the predicted results with the severe accident analysis codes, the RCIC system was speculated that had been driven by two-phase flow of water and vapor. In order to contribute to the clarification of the unexplained events related to the RCIC system of 1F2, distributions of void fraction, mixture velocity, etc. based on the flow rates of water and vapor and the number of rotation of the wheel in the RCIC turbine were predicted numerically. In the simulations, the structure of the current RCIC turbine was simply simulated and the two-dimensional analytical domain was considered. From the present study, it was found that the torque against a shaft of the wheel increases with increasing the accumulated water in the RCIC turbine and prevents the rotation.