Effectiveness analysis of hydrogen control system in AP1000 nuclear power plant under LB-LOCA

Abstract

The operational data and experience of AP1000 under accidents is insufficiency, it is necessary to conduct an effective analysis of the hydrogen control system to improve the safety of nuclear power plants. Three-dimensional computational fluid dynamics code Gasflow is used to study the severe accident caused by the cold leg LB-LOCA in the 1# steam generation compartment, and gravity injection failed. The hydrogen diffusion process, hydrogen distribution, and hydrogen risk in containment of the AP1000 nuclear power plant is analyzed. According to analysis results, hydrogen diffuse from source term compartment to containment dome space, and then to the bottom, obvious layered distribution is formed in containment. AP1000 hydrogen control system can effectively reduce the hydrogen concentration, eliminate the risk of flame acceleration in containment and deflagration to detonation transition in most compartments, but deflagration to detonation transition may occur in the source term compartment.