Seismic PSA of Kernkraftwerk Neckarwestheim Unit 2

摘要

In accordance with German nuclear regulations, a seismic PSA (SPSA) was performed on Kernkraftwerk Neckarwestheim Unit 2 (GKN II), a PWR located in Germany near Stuttgart. The study was conducted using techniques that comply with both German PSA guidelines and the ANS (now ASME/ANS) standard requirements for SPSA. The study found that the seismic design of the plant is quite high given the seismic hazard at the site. As a result, seismic core damage frequency contributes approximately 1% to total core damage risk of the plant. The risk is dominated by seismically-induced plant shutdown (no loss of offsite power) followed by random failures and human errors, and the dominant seismic events are at the low end of the hazard curve. The results are essentially insensitive to most seismic-related inputs, but are sensitive to the human error probabilities used. The walkdown did indentify few housekeeping items that could compromise the seismic performance of a few components, which the plant is addressing.