Recent safety hazards at aging nuclear plants
In the past three years, old or worn-out equipment has caused dozens
of incidents requiring plants to shut down.
December 9, 2001
BY CHRIS KNAP
The Orange County Register Since January 1999, worn-out equipment at
U.S. nuclear power plants has caused more than 50 fires, radiation or
steam leaks, or other serious safety hazards requiring shutdown of the
nuclear reactor. Here are details of some of the most serious
January 1999: Inadequate maintenance led to a six-hour hydrogen fire
on the roof of the control building at J.A. Fitzpatrick in Syracuse,
N.Y., forcing a plant shutdown.
August 1999: A cooling- water drain line in Callaway, Mo., broke
because of severe corrosion, forcing a reactor shutdown. A subsequent
inspection revealed at least 10 areas where pipes had decayed and were
in danger of breaking.
1999-2000: Millstone in Waterford, Conn., had to repeatedly shut down
due to failures of the reactor control-rod drive system, including
control rods that came loose and dropped into the reactor. The plant
operator blamed failed insulation and damaged electrical leads.
February 2000: A steam generator tube ruptured at Indian Point 2 in
New York, contaminating 19,000 gallons of cooling water and releasing
radioactive steam into the atmosphere.
May 2000: A failed electrical conductor at Diablo Canyon 1 in San Luis
Obispo County triggered a fire that cut power to the coolant and
circulating water pumps that keep the nuclear core from overheating.
August 2000: Peach Bottom Unit 3, in Pennsylvania, was forced into
emergency shutdown when an instrument valve failed and caused a leak
of contaminated reactor cool ant outside of primary containment. A
similar valve failure and leak of radiation had occurred May 28, 2000,
but the valves were not replaced.
October 2000: At V.C. Summer, in South Carolina, a 29- inch diameter
coolant pipe, with walls more than 2 inches thick, suffered a crack
due to water stress corrosion, creating a leak of radioactive cooling
water. Crack indications were later found at four more reactor inlets.
November 2000 to April 2001: After receiving a 20-year license
extension, operators of Oconee 1, in Seneca, S.C., found 19 cracks in
the reactor where control rods pass through to the nuclear core.
Radioactive cooling water had been leaking into the containment sump.
In February nine leaks were found in Oconee 3, which had been taken
down for refueling. Oconee 2 was later found to have four leaking
January 2001: Failure of an 18-year-old valve at North Anna, Va.,
created a leak of radioactive coolant of more than 10 gallons per
minute, forcing a shutdown of the reactor.
February 2001: A 20-year-old circuit breaker at San Onofre 3, near
Camp Pendleton, failed to close, creating a 4000-volt arc and fire
that cut power to coolant control systems, drowned emergency switching
valves and shut down emergency oil pumps, destroying the Unit 3
generator shaft. Currently, 150 identical breakers remain in service
at the plant.
February 2001: After Arkansas 1 was re-licensed for 20 years,
extensive cracking was found on the control-rod drives and
thermocouple nozzles entering the nuclear reactor.
August 2001: Failure of a valve at Palo Verde 3, in Arizona, caused a
leak of radioactive cooling water from the irradiated fuel-cooling
pool into the reactor containment building, forcing a reactor
Source: Nuclear Regulatory Commission inspection reports, incident
reports and technical bulletins.