Archive for Monday, July 17, 1995


July 17, 1995


A Missouri nuclear power plant has cracks that engineers predict will also be found in the Wolf Creek nuclear plant in Burlington.

The Wolf Creek nuclear power plant's sister facility in Missouri has developed the same kinds of cracks that have forced expensive repairs at other nuclear power plants in the United States and the permanent shutdown of at least one of them.

Nuclear power critics say undetected cracks in any of 71 similar plants, including Wolf Creek, could cause a catastrophic disaster comparable to the deadly 1986 Chernobyl accident.

"It's a cause for concern throughout the industry," said Mike Cleary, a spokesperson for Union Electric Co. of St. Louis, which owns the Calloway nuclear power plant near Fulton, Mo., about 100 miles west of St. Louis.

Cracks in steam generator tubes at Calloway were discovered this spring when the plant was shut down for routine refueling and testing.

Cleary said the tests found 31 indications of cracks in 29 tubes. All but three of the indications were determined to be stress corrosion cracks, and the tubes were plugged, preventing pressurized radioactive water from entering them but also slightly reducing the plant's efficiency. An additional nine tubes were plugged for other reasons.

In all, 178 of the plant's 22,000 steam generator tubes have been plugged, most due to wear caused by anti-vibration bars. This spring marked the first time that cracks due to corrosion were detected since the plant started generating power in 1984.

Calloway's refueling outage began March 25. The plant restarted May 11.

Meanwhile, federal regulators are just starting a review of data ordered from utility companies this spring to asses the likelihood of corrosion-related accidents.

Officials at Wolf Creek, near Burlington, about 55 miles south of Topeka, say the cracks at Calloway do not mean bad news should be expected at the Kansas plant -- even though Wolf Creek and Calloway are similar in many respects.

Both were built in the mid 1980s using a common design called the Standardized Nuclear Unit Power Plant System, or SNUPPS.

But there are some differences, and Calloway and Wolf Creek officials say the heat-treated alloy used in Wolf Creek's steam generator tubes should withstand greater stresses than tubes at Calloway. Thus far, cracks have not been found at Wolf Creek.

But Wolf Creek officials have acknowledged that they expect to find cracks eventually.

"Next spring we will look for the same type of cracking that Calloway has seen," said Mona Grimsley, a Wolf Creek spokesperson.

The $3 billion plant, jointly owned by Kansas Gas & Electric Co., Kansas City Power & Light Co. and Kansas Electric Power Cooperative, started generating power in 1985.

Power plant operators across the nation are worried about the enormous cost of replacing key components decades sooner than expected because of aging and corroding parts.

Nuclear power critics, including Bob Pollard, a former Nuclear Regulatory Commission engineer, have argued that all pressurized water reactors should be shut down and tested immediately because older testing methods have been proved worthless.

The NRC has rejected such requests, saying the risk of an accident is minor.

"We have had corrosion in basically every single steam generator," Pollard said. "Whether it's better or worse in one plant is besides the point.

"We have a problem with steam generators that is unsolvable. Wolf Creek may be right. The best thing we can hope for is they have fewer problems than other plants. That doesn't mean the problems they will have will be insignificant. It won't matter what they do, they're not going to stop the corrosion."

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