FIRE IGNITION FREQUENCY ESTIMATION USING RECENT FIRE EVENTS DATA

摘要

The generic fire ignition frequencies used in fire PRAs were originally developed and provided in NUREG/CR-6850. An interim revision of those fire frequencies to emphasize the more recent but still 10 year old data was developed by the Electric Power Research Institute (EPRI) and incorporated in a supplement to NUREG/CR-6850. This paper describes the initial analysis of new fire event data to estimate updated fire ignition frequencies as a potential improvement for fire PRA applications. The new fire event data extends the EPRI fire events database an additional 10 years, through 2009. That data along with the existing historical data has been analyzed for consistency and applicability for estimating updated fire ignition frequencies. The fire event data were collected, coded and classified over time using somewhat different data sources with varying information quality and completeness. Therefore, data quality and quantitative factors have also been assessed to ensure proper use of data. In particular it was noted that the fire event data exhibits a discontinuity in the occurrence rate for the period around 1990-1999. Therefore, the methodology for estimating the updated fire ignition frequencies for fire PRAs that was previously developed was adjusted to account for the data anomalies. Then the fire event data was applied to assess fire ignition frequencies using the revised methods. The updated frequencies have been compared with fire frequencies currently being used in fire PRAs with initial insights as to differences indicated.