Nuclear Technology / Volume 160 / Number 3 / December 2007 / Pages 294-307
Technical Paper / Reactor Safety
The severe accident management guideline (SAMG) was developed and implemented at the Kuosheng nuclear power plant (NPP) in Taiwan at the end of 2003. The Kuosheng NPP is a Mark-III boiling water reactor (BWR)-6 located in the north of Taiwan. The SAMG of the Kuosheng NPP is developed based on the BWR Owners Group Emergency Procedure and Severe Accident Guidelines. In this paper, MELCOR 1.8.5 is used to investigate the effectiveness of the Kuosheng SAMG and to analyze the reactor coolant system (RCS) bleed-and-feed strategy in a postulated station blackout (SBO) accident since this accident is a dominant sequence that can induce core damage. These simulation results can be applied for the typical BWR-6 NPPs. Based on the simulation results, the major events of an SBO accident without any operator actions, including core uncovery, cladding oxidation, hydrogen generation, fuel relocation, vessel failure, and containment failure, are well presented. The RCS bleed-and-feed strategy can cool down the hot core and bring the vessel into the stable condition in the SBO accident with high-pressure core spray injection according to the Kuosheng SAMG. The reactor pressure vessel depressurization before the reactor liquid level reaches one-fourth of the core liquid level can prevent damage to the core fuel. However, the water temperature of the suppression pool will reach saturation temperature, and the containment pressure may challenge the containment integrity. These phenomena were not considered while developing the SAMG.