Safety Depressurization System Capability for High Pressure Core Melting Accidents in APR1400

In the case of a high-pressure core melt-down accident, the released molten material from a reactor vessel can lead to increase the containment pressure and temperature by heat transfer via direct contact between the containment atmosphere and the dispersed molten material. This phenomenon is known as direct containment heating (DCH). High-pressure melt ejection (HPME) and DCH became severe accident (SA) safety issues in the 1980s. Many studies were performed in the USA to understand these events during the 1980s and 1990s. Currently, a reliable safety depressurization system (SDS) is required to prevent HPME/DCH events. A number of ALWRs such as EPR, APWR and AP1000 have been adopted SDS in their design. Especially, a dedicated SDS for severe accident mitigation is required in Europe. The APR1400 is designed with dedicated SDS for severe accidents in order to meet European requirements. In this paper, an evaluation of the SDS capacity is performed for high-pressure accidents of the APR1400 using MAAP4: The result can be expected to be technical basis for a serve accident management guidelines (SAMGs)