7. Circulating Water System Modes
Cooling towers
reduce how much
water is drawn from
lakes, rivers, and
oceans by re-using
water.
Water is drawn to
replace water vapor
emitted from the
cooling towers.
8. There’s More
Nuclear plants also take water from the nearby
lake, river, or ocean and use it to cool
components and buildings.
This cooling system, commonly called the
Service Water system, supplies cooling water to
air conditioning units, lube oil coolers,
emergency diesel generator engine coolers,
spent fuel pool heat exchangers, and so on.
11. Service Water Risk Table 4.8-1
Total
Plant Type Internal SW CDF SW %
CDF (mean) Contribution Contribution
Calvert 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 19
Turkeythe 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 12
Quad 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 <1
Sequoyah 1 PWR 5.7x10-5 2.4x10-7 <1
Peach Bottom BWR 4.5x10-6 1.4x10-6 22
2
Grand Gulf BWR 4.1x10-6 5.6x10-7 14
12. 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 3
07/2007 Brunswick 1
04/1994 Salem 1
01/1982 D C Cook 1&2
06/1972 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
14. Location of leak
was just above
concrete floor
where service
water pipe rises
from underground
run and enters
safety-related
cooling tower
(part of Ultimate
Heat Sink).
15. X
X
Non-safety related cooling
towers may be
unavailable, so safety-
related cooling towers
ensure adequate cooling for
Service Water.
16. Service Water system degradation
adversely affected safety-related
equipment at Indian Point Unit 2
(October 1980) and forced a shut down
with regulatory sanctions.
17. Two headers provided
Service Water to cool
the FCUs
Common header
routed Service Water
from FCUs
Containment cooling was provided
There were leaks.
by five Fan Cooler Units (FCUs).
Lots of leaks.
Lots of time.
18. While the reactor operated, over 100,000
gallons of leaked water flooded the
containment and submerged the lower 9 feet of
the reactor vessel.
The NRC fined the company $210,000 in 1980.
