Analysis of core damage frequency: Sequoyah, Unit 1, internal events

Technical Report · Sun Apr 01 04:00:00 EDT 1990

OSTI ID:6913280

Bertucio, R C; Brown, S R ^[1]

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1. E.I. Services, Kent, WA (USA)

This document contains the accident sequence analyses of internally initiated events for the Sequoyah, Unit 1 nuclear power plant. This is one of the five plant analyses conducted as part of the NUREG-1150 effort by the Nuclear Regulatory Commission (NRC). NUREG-1150 documents the risk of a selected group of nuclear power plants. The work performed and described here is an extensive reanalysis of that published in February 1987 as NUREG/CR-4550, Volume 5. It addresses comments from numerous reviewers and significant changes to the plant systems and procedures made since the first report. The uncertainty analysis and presentation of results are also much improved. The mean core damage frequency at Sequoyah was calculated to be 5.7E-5 per year, with a 95 percent upper bound of 1.8E-4 and 5 percent lower bound of 1.2E-5 per year. Loss of coolant type accidents were the largest contributors to core damage frequency, accounting for approximately 62 percent of the total. The next most dominant type of accidents were station blackout (loss of all ac power). These sequences account for 26 percent of core damage frequency. No other type of sequence accounts for more than 10 percent of core damage frequency. The numerical results are dominated by failure to initiate high pressure recirculation due to operator error following loss of coolant accidents. Considerable effort was expended on the modeling of very small LOCAs and station blackout sequences, including the development of a reactor coolant pump seal LOCA model through elicitation of expert opinion. This report evaluates core damage frequency from internally initiated events. The consequences of these accidents are evaluated and reported under separate cover.

• Research Organization: Nuclear Regulatory Commission, Washington, DC (USA). Div. of Systems Research; Sandia National Labs., Albuquerque, NM (USA)
• Sponsoring Organization: NRC
• DOE Contract Number: AC04-76DP00789
• OSTI ID: 6913280
• Report Number(s): NUREG/CR-4550-Vol.5-Rev.1-Pt.1; SAND--86-2084-Vol.5-Rev.1-Pt.1; ON: TI90010760
• Country of Publication: United States
• Language: English

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