抄録
The present study investigates the effects of predominant parameters on the downcomer penetration of emergency core cooling (ECC) water under a counter current flow in the downcomer during refill phase in PWR loss-of-coolant accidents.
As the results, the following were revealed:
(1) Dominant parameters which correlate best for PWR downcomer penetration of ECC water are (i) dimensionless superficial velocities j*sg and j*sl of upward gas and downward liquid, based on the gap of annulus downcomer flow channel S, (ii) aspect ratio W/S of circumferential length W to gap of downcomer S, and (iii) dimensionless superficial velocity J*f, IN of ECC water injected into the downcomer, based on the circumferential length W of downcomer.
(2) Especially, the aspect ratio W/S plays an important role for scaling up to a full scale.BR>(3) The correlation proposed in this study for both complete bypass and partial penetration of ECC water which is supplied to the downcomer gives much better prediction to the experimental results than those by previous studies which have not taken into account the effects of aspect ratio of annulus downcomer flow channel.
