The Analysis of Effectiveness of BWR/6 URG Strategies

Abstract

After the Fukushima Daichii accidents, Taiwan Power Company developed a strategy to cope with such extended SBO (Station Blackout) cases at nuclear power plants, which called URG. The MAAP and PCTRAN were used to perform the study for Kuosheng BWR/6 nuclear power plant (NPP) ultimate response guideline (URG). The main actions of URG are the depressurization and low pressure water injection of the reactor and the venting of the containment. This study focuses to confirm the URG efficiency. The analysis results depict that following the URG, the fuel can be covered by the coolant, no exposure. It can also prevent the radiation release and the large evacuation. It indicated that Kuosheng NPP was at the safe situation. It shows that the two-step depressurizations can extend the time of the preparation of alternate water source. The minimum injection rate to prevent the fuel to expose is 192 gpm in MAAP.

Analyzing Simplified BWR Inherent Safety System using IAEA Generic Boiling Water Reactor Simulator

“…If the reactor's water level doesn't fall beyond the top of active fuel-TAF, the reactor will not be damaged. In Kuosheng's BWR/6 reactor (reactor with thermal power of 2896 MWth) simulation, the water level will not fall to TAF during feedwater trip if there is water injection with a minimum of 12.11 kg/s [27]. In this simulator, the reactor received additional water from core spray at 180 kg/s, much more than the minimum limit in Wang's study.…”