Modeling of Pickering NGS B Heat Transport System Seismic Boundary Leak Tightness Test

Abstract

Both Class IV and Class III power supplies may be lost following a seismic event in Pickering NGS B. In an operating unit, such an event would result in reactor trip with the Heat Transport System (HTS) remaining at hot and pressurized conditions, and decay power being removed by single-phase thermosyphoning. Under these conditions, HTS pressure and inventory must be maintained within the seismically qualified portion of the system to prevent the breakdown of thermosyphoning. This paper presents the model employed to simulate the HTS pressure following a seismic event, and the comparison between numerical results and actual data obtained with the recently developed and implemented P-079 test.