SCREENING OF EXTERNAL HAZARDS PER PART 6 OF THE PRA STANDARD FOR THE AP1000~® PLANT

摘要

Westinghouse Electric Company has completed screening of external hazards per Part 6 of the ASME/ANS PRA Standard for the AP1000m plants currently under construction in the United States. Specifically this was done for units 3 and 4 at the Vogtle site in Georgia for Southern Nuclear Company and for units 2 and 3 at the V. C. Summer site in South Carolina for South Carolina Electric and Gas. This paper describes how screening was accomplished. Potential external hazards were first identified based on various industry related tabulations and supplemented as needed for each site. Screening was then performed in three stages. First, each of the identified hazards was evaluated per preliminary screening criteria that are based on evaluating the damage potential of the hazard, annual frequency of the hazard, proximity of the hazard to the site, being included in another hazard, and available response time to eliminate the potential threat posed by the hazard. The second stage was to perform a more detailed qualitative assessment of the remaining hazards based on additional site-specific considerations. The final stage was to perform a conservative quantitative assessment to screen the remaining hazard.