Intentional depressurization accident management strategy for pressurized water reactors
- EG and G Idaho, Inc., Idaho Falls, ID (United States)
In a previous investigation of the Surry nuclear power station, it was concluded that intentional depressurization of the reactor coolant system (RCS) could prevent or mitigate the effects of direct containment heating (DCH) during a station blackout transient. Two strategies, early and late depressurization, were investigated as methods to mitigate DCH. The investigation concluded that since there are greater opportunities to recover plant functions before core damage occurs and operator response uncertainties are lessened, the strategy of late depressurization is preferred over early depressurization. The results of the Surry analysis were extended to other US pressurized water reactors (PWRS) in order to evaluate their capability to successfully employ the late depressurization strategy to prevent or mitigate DCH. By applying appropriate scaling factors to the selected key parameters, this evaluation resulted in the categorization of four PWR groups based upon their perceived late depressurization capability. In this report, a PWR representative of each of the four PWR groups was chosen for detailed analysis of its capability to intentionally depressurize employing the late depressurization strategy. The phenomenological behavior, hardware performance, and operational performance of these PWRs during the intentional depressurization strategy were considered. The phenomenological behavior was analyzed using the SCDAP/RELAP5/MOD3 severe accident analysis code. The results of these evaluations were then extended to the remaining PWRs comprising each PWR group.
- Research Organization:
- Nuclear Regulatory Commission, Washington, DC (United States). Div. of Systems Research; EG and G Idaho, Inc., Idaho Falls, ID (United States)
- Sponsoring Organization:
- Nuclear Regulatory Commission, Washington, DC (United States)
- DOE Contract Number:
- AC07-76ID01570
- OSTI ID:
- 10154204
- Report Number(s):
- NUREG/CR--5937; EGG--2688; ON: TI93012825
- Country of Publication:
- United States
- Language:
- English
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Depressurization as an accident management strategy to minimize the consequences of direct containment heating
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Related Subjects
210200
22 GENERAL STUDIES OF NUCLEAR REACTORS
220900
CALVERT CLIFFS-1 REACTOR
CALVERT CLIFFS-2 REACTOR
CONTAINMENT
DEPRESSURIZATION
HEAT TRANSFER
HEATING
HYDRAULICS
MANAGEMENT
OCONEE-1 REACTOR
OCONEE-2 REACTOR
OCONEE-3 REACTOR
PIPES
POWER REACTORS
NONBREEDING
LIGHT-WATER MODERATED
NONBOILING WATER COOLED
PWR TYPE REACTORS
R CODES
REACTOR ACCIDENTS
REACTOR COOLING SYSTEMS
REACTOR SAFETY
REACTOR VESSELS
RELIABILITY
S CODES
SENSITIVITY ANALYSIS
SEQUOYAH-1 REACTOR
SEQUOYAH-2 REACTOR
SURRY-1 REACTOR
SURRY-2 REACTOR
SURRY-3 REACTOR
SURRY-4 REACTOR