Sensitivity Analyses of Thermal Hydraulic Parameters in ATWS by Rods Failure-Loss of Offsite Power of the Third Generation Nuclear Power Plant

The beyond basic design accidents of second and second plus generation nuclear plants are assessed in a method of best estimate assumption. The Nuclear Power Design Safety Regulations (HAF102–2004) are updated in 2016, the beyond basic design accidents are revised as Design Extend Conditions, which includes Design Extend Conditions without core melt (DEC-A) and Design Extend Conditions with core melt (DEC-B). It is pointed that conservative design should be considered appropriately in order to avoid the steep side effect. To meet the requirements of the new regulations, the ATWS by Rods Failure-loss of offsite power of the third-generation nuclear power plant is analyzed in this paper. Sensitivity analyses of thermal hydraulic parameters are calculated to study their influence on the accident consequences. It is proved that the steep side effect does not appear even the conservative is taken into account. However, the acceptance before is too strict to satisfy, the more proper acceptance should be used.