PWR depressurization analyses

Conference · Tue Dec 31 23:00:00 EST 1991

OSTI ID:6682591

Brownson, D A; Dobbe, C A; Knudson, D L

Early containment failure resulting from direct containment heating (DCH) has been identified as a potential contributor to the risk of operating a pressurized water reactor (PWR). One important factor needed to evaluate the contribution of DCH to risk is the conditional probability that, given a core melt, the primary system will be at high pressure when the reactor vessel lower head fails. Two mechanisms that could reduce the pressure during a station blackout core melt accident are discussed. First, natural circulation in the reactor coolant system (RCS) could cause a temperature-induced failure of the RCS pressure boundary, which could result in unintentional (without operator action) depressurization. Second, plant operators could open relief valves in an attempt to intentionally depressurize the RCS prior to. lower head failure. Results from analytical studies of these two depressurization mechanisms for select PWRs are presented.

• Research Organization: EG and G Idaho, Inc., Idaho Falls, ID (United States)
• Sponsoring Organization: NRC; Nuclear Regulatory Commission, Washington, DC (United States)
• DOE Contract Number: AC07-76ID01570
• OSTI ID: 6682591
• Report Number(s): EGG-M-92501; CONF-9210204--5; ON: DE93005203
• Country of Publication: United States
• Language: English

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