Analysis of Loss-of-Offsite-Power Events 1987-2018

Technical Report · Mon Jul 01 00:00:00 EDT 2019

DOI:https://doi.org/10.2172/1755379· OSTI ID:1755379

Johnson, Nancy ^[1]; Ma, Zhegang ^[1]

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1. Idaho National Lab. (INL), Idaho Falls, ID (United States)

Loss of offsite power (LOOP) can have a major negative impact on a power plant’s ability to achieve and maintain safe shutdown conditions. LOOP event frequencies and times required for subsequent restoration of offsite power are important inputs to plant probabilistic risk assessments. This report presents a statistical and engineering analysis of LOOP frequencies and durations at U.S. commercial nuclear power plants. The data used in this study are based on the operating experience during calendar years 1987 through 2018. LOOP events during critical operation that do not result in a reactor trip are not included. Frequencies and durations were determined for four event categories: plant-centered, switchyard-centered, grid-related, and weather-related. No significant trends in critical operation LOOP frequencies over the most recent 10-year period are identified. Adverse trends in LOOP durations are identified for switchyard-centered and grid-related LOOPs, as well as overall LOOPs during critical operation and overall LOOPs during shutdown operation. Both grid-related and weather-related LOOP events are found to show statistically significant seasonality. The engineering analysis of LOOP data shows that human errors have been much less frequent since 1997 than in the 1987–1996 time period.

• Research Organization: Idaho National Laboratory (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: Nuclear Regulatory Commission; USDOE Office of Nuclear Energy (NE)
• DOE Contract Number: AC07-05ID14517
• OSTI ID: 1755379
• Report Number(s): INL/EXT--19-54699-Rev000
• Country of Publication: United States
• Language: English

Related Subjects

22 GENERAL STUDIES OF NUCLEAR REACTORS
Duration
frequency
loss of offsite power
operating experience