Semiscale Recovery Investigations: A Comparison of Results from Semiscale Mod-2C Small Break LOCA (Loss-of-Coolant Accidents) Without HPI (High Pressure Injection) Tests

摘要

Inadequate core cooling conditions can result in small break loss-of-coolant accidents (SBLOCAs) without high pressure injection (HPI) unless appropriate operator action is taken. Results from the S-NH test series, performed in the Semiscale Mod-2C facility, show that for SBLOCAs below 2.1% inadequate core cooling results before the accumulator actuation pressure is reached. Various recovery operations were used in the experiments in the S-NH test series to mitigate the heater rod temperature excursions and lower the primary system pressure to the accumulator actuation pressure. These recovery operations included steam generator secondary steam-and-feed and primary coolant pump restart. In addition, in one of the experiments steam generator secondary steam-and-feed operations were begun before a heater rod temperature excursion began. The effectiveness each procedure had in mitigating the heater rod temperature excursions is discussed and compared. (ERA citation 12:009173)