Evaluation of potential severe accidents during low power and shutdown operations at Grand Gulf, Unit 1. Analysis of core damage frequency from internal events for plant operational state 5 during a refueling outage (Main report, Sections 1--9): Volume 2, Part 1A
- Sandia National Labs., Albuquerque, NM (United States)
- Science and Engineering Associates, Inc., Albuquerque, NM (United States)
- Science Applications International Corp., Albuquerque, NM (United States); and others
The program objectives include assessing the risks of severe accidents initiated during plant operational states (POS) other than full power operation and comparing the estimated core damage frequencies, important accident sequences, and other qualitative and quantitative results with those accidents initiated during full power operation. The objective of the Phase 1 study was to identify potential vulnerable plant configurations, to characterize the potential core damage accident scenario frequencies, and to provide a foundation for a detailed Phase 2 analysis. In Phase 2 POS 5 (approximately Cold Shutdown) during a refueling outage was selected as the plant configuration to be analyzed. System models applicable for POS 5 conditions on the way down to refueling and on the way back up from refueling were developed and supporting thermal hydraulic analyses were performed to determine both the timing of the accidents and success criteria for systems. Initiating events that may occur during POS 5 were identified and accident sequence event trees were developed and quantified. Surviving sequences were examined for recovery potential, appropriate human recovery actions were incorporated into the sequence cut sets, and the sequences were then requantified. Those sequences surviving this preliminary recovery analysis were then reexamined during a time window analysis. The mean core damage frequency of the Grand Gulf plant due to internal events for POS 5 during a refueling outage is 2.0E-06 per year, and the 5th and 95th percentiles are 4.1E-07 and 5.4E-06 per year, respectively. This compares to the total core damage frequency of 4.0E-06 per year estimated in the NUREG-1150 study of full power operations.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (United States). Div. of Safety Issue Resolution; Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC04-94AL85000
- OSTI ID:
- 10170061
- Report Number(s):
- NUREG/CR-6143-Vol.2-Pt.1A; SAND-93-2440-Vol.2-Pt.1A; ON: TI94015869; BR: GB0103012; TRN: 94:014779
- Resource Relation:
- Other Information: PBD: Jun 1994
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
GRAND GULF-1 REACTOR
RISK ASSESSMENT
REACTOR FUELING
REACTOR SHUTDOWN
REACTOR KINETICS
REACTOR CORES
DAMAGE
PROBABILISTIC ESTIMATION
TRANSIENTS
LOSS OF COOLANT
AFTER-HEAT REMOVAL
FAULT TREE ANALYSIS
SYSTEMS ANALYSIS
ENGINEERED SAFETY SYSTEMS
220900
210100
REACTOR SAFETY
POWER REACTORS
NONBREEDING
LIGHT-WATER MODERATED
BOILING WATER COOLED