Loop seal clearing and refilling during a PWR small-break LOCA

Abstract

During a cold-leg small-break loss-of-coolant accident (LOCA) in a Westinghouse-type pressurized water reactor (PWR), the core liquid level is depressed temporarily before steam clears liquid out of the primary-loop loop seals. The loop seal clearing and associated core level depression may occur repeatedly if the emergency core coolant (ECC) refills the loop seals after clearing. This paper presents an interpretative description of experimental results on loop seal clearing and refilling phenomena obtained at the ROSA-IV Large Scale Test Facility (LSTF).