Bogus valve parts are the latest counterfeit equipment problem to strike the nuclear power industry, which earlier was hit with faulty bolts and circuit breakers.

The utility that discovered what the Nuclear Regulatory Commission called counterfeit valve parts says they were found and weeded out before being put to use.The parts were meant for valves controlling the steam supply to the turbines at the Palisades Plant of Consumers Power Co. near South Haven, Mich., said Brian Grimes of the commission's Office of Nuclear Reactor Regulation.

Palisades has been shut down to repair steam generator leaks, but Consumers hopes to restart it before the end of the year.

Some of the questionable valve parts were installed after they passed special tests that showed they met specifications, said Paul Knopick, a company spokesman in Jackson, Mich.

A bad parts failure might cause a valve to remain shut or open, not responding to commands, and that might cause an automatic reactor shutdown but would not mean a nuclear accident, said Grimes.

The commission staff last week issued a special notice to utilities asking them to be on the lookout for bogus valve parts of all kinds. This could be difficult, because a large nuclear plant might have 40,000 valves, 10 times as many as a coal plant of the same power.

"Valves are quite frequently refurbished," said Grimes.

The notice said counterfeiting "may extend to other manufacturers" besides the company whose parts were misrepresented, Masoneilan-Dresser Co.

Consumers Power discovered the faulty parts when a repaired valve leaked, Grimes said. "Some of the parts they had procured turned out to be misrepresented and counterfeit," and an investigation by the manufacturer concluded "there appeared to be a counterfeit market," he said.

Knopick would not go as far as Grimes and say the parts had been misrepresented: "It's too early to conclude that. That's still under investigation."

Counterfeit bolts and other fasteners were found in several places two years ago. The commission staff has concluded that there is enough margin for error in plant designs so that no safety problem should arise. More bolts than necessary are used and they are not stressed to the limit, the commission staff says.

Following the discovery of counterfeit circuit breakers in California earlier this year, the commission staff ordered utilities to inspect breakers, replacing those that didn't meet specifications, with reports of findings by March. Utilities would have to justify retaining any that couldn't be inspected.

Some instances of counterfeiting appear to be the relabeling of normal commercial equipment as having been manufactured under the stricter controls that are supposed to apply to items meant for nuclear plants, officials said.

Grimes said Tuesday a different form of counterfeiting was recently found at the Quad Cities plant of Commonwealth Edison Co. in Illinois. A bigger circuit breaker than those involved in California had been put through a "substandard refurbishment" in which parts were used that were "non-genuine and non-conforming dimensionally," Grimes said.

"A number of activities are under way to identify the source of the refurbishment," he said.