MAAP5 simulation of AP1000 severe accident induced by pressurizer safety valve stuck-open

摘要

The Modular Accident Analysis Program version 5(MAAP5) is a computer code that can simulate the response of light water reactor power plants during severe accident sequences. The present work aims to simulate the severe accident of AP1000 with the Modular Accident Analysis Program version 5 (MAAP5). The pressurizer (PZR) safety valve stuck-open is essentially a small break loss-of-coolant accident which becomes one of the major concerns on severe accident initiating event of pressurized water reactor (PWR). For such improbable accidents, four cases of PZR safety valve stuck-open accidents are simulated for comparison. This analysis is performed at 100% core power with different assumptions. For all cases, the primary system pressure can long term be maintained at a low level, and the ERVC system has enough capability to remove the heat from the molten pool. The total mass of hydrogen production in the core of the cases without auto depressurization system (ADS) is more significant than those cases with ADS. The results are meaningful and significant for comprehending the detail process of AP1000 severe accident, which is the basic standard for establishing the severe accident management guidelines. (C) 2020 Elsevier Ltd. All rights reserved.