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Recent safety hazards at aging nuclear plants



FYI

Norm



> Source:

> "http://www.ocregister.com/news/nukeax01209cci5.shtml";>http://www.ocregister.com/news/nukeax01209cci5.shtml</A>

> =========================================================

> 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 accidents:

>

> 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 control-rod nozzles.

>

> 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 shutdown.

>

> Source: Nuclear Regulatory Commission inspection reports, incident

> reports

> and technical bulletins.

>

>

>

>

>

>







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