Analysis of Mobile Diesel Generator Operation to cope with Extended Loss of all AC Power in Nuclear Power Plant

Based on the lessons learned from the accident at Fukushima NPP, many countries prepared and carried out the mitigation strategies to cope with ELAP accidents. This paper analyzed one of the coping strategy for ELAP, which is the operation of mobile DG and its pump loads. In case of mobile DG operation, the voltage and frequency of Class 1E 4.16kV safety bus could be oscillated by motor starting current, when the motor pumps connect to Class-1E 4.16kV safety bus in sequence. Thus, this paper reviewed the voltage and frequency dynamic responses of Class 1E 4.16kV safety bus and verify the adequacy of the mobile DG operation and motor pumps starting, according to the assumed ELAP coping scenarios. This paper found that the large capacity motor load starts later, it could cause the vulnerable conditions, such as motor staring failure, motor loads trip, motor mechanical stress, etc.