Circulating Water System ModesCooling towersreduce how muchwater is drawn fromlakes, rivers, andoceans by re-usingwater.Water is drawn toreplace water vaporemitted from thecooling towers.
There’s MoreNuclear plants also take water from the nearbylake, river, or ocean and use it to coolcomponents and buildings.This cooling system, commonly called theService Water system, supplies cooling water toair conditioning units, lube oil coolers,emergency diesel generator engine coolers,spent fuel pool heat exchangers, and so on.
Service Water Risk Table 4.8-1 Total Plant Type Internal SW CDF SW % CDF (mean) Contribution ContributionCalvert Cliffs PWR 1.3x10-4 1.4x10-5 11 1 Risk associated with Service Water (SW)Point Beach 1 problems can1.4x10-4 because of system PWR be high 2.6x10-5 19Turkeythe common mode factor – loss of cooling Point 3 PWR 7.1x10-5 3.4x10-6 5 provided by service water can disable St. Lucie 1 PWR 1.4x10-5 1.8x10-6 13 emergency systems and their backups. ANO-1 PWR 8.8x10-5 1.1x10-5 12Quad Cities 1 BWR 9.9x10-5 3.0x10-5 30 Cooper BWR 2.9x10-4 1.9x10-4 65 Surry 1 PWR 4.0x10-5 1.5x10-8 <1Sequoyah 1 PWR 5.7x10-5 2.4x10-7 <1Peach Bottom BWR 4.5x10-6 1.4x10-6 22 2 Grand Gulf BWR 4.1x10-6 5.6x10-7 14
Which have caused problems? 03/2006 FitzPatrick 02/2000 Ginna 01/1996 Wolf Creek 01/1982 Salem 2 01/1977 Salem 2 04/2007 Salem 1 06/2004 San Onofre 307/2007 Brunswick 1 04/1994 Salem 101/1982 D C Cook 1&206/1972 Quad Cities 1 06/1989 Salem 2 08/1970 Oyster Creek 04/2003 D C Cook 1&2 10/2008 Diablo Canyon 1 06/2001 Point Beach 2 07/2006 Calvert Cliffs 1 06/2001 Point Beach 2 09/1993 St. Lucie 1 04/1976 Nine Mile Point 1 08/1984 St. Lucie 2
Location of leakwas just aboveconcrete floorwhere servicewater pipe risesfrom undergroundrun and enterssafety-relatedcooling tower(part of UltimateHeat Sink).
X XNon-safety related coolingtowers may beunavailable, so safety-related cooling towersensure adequate cooling forService Water.
Service Water system degradationadversely affected safety-relatedequipment at Indian Point Unit 2(October 1980) and forced a shut downwith regulatory sanctions.
Two headers provided Service Water to cool the FCUs Common header routed Service Water from FCUsContainment cooling was provided There were leaks.by five Fan Cooler Units (FCUs). Lots of leaks. Lots of time.
While the reactor operated, over 100,000gallons of leaked water flooded thecontainment and submerged the lower 9 feet ofthe reactor vessel.The NRC fined the company $210,000 in 1980.