Evaluation of cooling capacity with more fuel stored in the spent fuel pool of the Kuosheng plant

The storage capacity of the spent fuel pool (SFP) of the Kuosheng plant will be insufficient in recent years. Fuel racks are suggested to be installed in the cask loading pool to increase the capacity by more 440 assemblies. Thus, the design-basis analysis for the SFP cooling should be performed. The pool temperature under normal and abnormal conditions is analyzed by solving the simplified energy equation. Furthermore, a lumped model and a detailed model have been developed using GOTHIC in this study. The bulk pool temperature calculated from the lumped model is in good agreement with that from the energy balance, and is below the required limit set by regulatory authority. The detailed model can be used to determine the local temperature during the transient events, which is beyond the capability of the lumped model. The analyzed result meets the requirement that no boiling shall occur in the normal condition. The time available for corrective actions after loss of forced cooling is also evaluated. With makeup water, the time when the SFP level drops to 3 m above the fuel top is considerably extended. The cooling capability of the Kuosheng SFPs still meets the safety requirements with storing more assemblies.