NEWPORT, Mich. - DTE Energy's Fermi 2 nuclear plant near here remained shut down yesterday for the second day in a row with the utility being unable to identify the source of a hydrogen leak.
Len Singer, utility spokesman, said the plant had been operating for an unknown length of time with hydrogen leaking from the plant's main turbine generator into the stator cooling water system.
The leak was minor enough that it posed no safety hazard, he said.
According to a company notification of the event that was posted on the Nuclear Regulatory Commission's Web site, the reactor was shut down at 11:09 a.m. Wednesday.
Mr. Singer said that was done to protect the main turbine generator from being damaged.
He said it is unknown when the nuclear plant will resume operation because the problem was still being assessed.
It was unknown how much, if any, damage might have occurred, he said.
"The reactor is in a safe and stable condition," Mr. Singer said.
"The condition does not present a safety risk to workers or the public."
Viktoria Mitlyng, NRC spokesman, confirmed the company's explanation and said the agency also had known about the hydrogen leak for an unknown amount of time before the shutdown.
She agreed there was no threat to the public and said there is no real average time for such repairs.
Hydrogen leaks don't happen frequently, but they are not incredibly rare, she said.
"With these things, it's really hard to say because they need to identify the source of the leak. The amount of time will vary depending on what they find," Ms. Mitlyng said.
She said the leak was within the NRC's regulatory threshold.
Fermi 2 is a boiling-water reactor that is operated by Detroit Edison, a DTE subsidiary.
The nuclear plant is along the western Lake Erie shoreline, about 30 miles north of Toledo.
About a third of the nation's 104 nuclear reactors have a boiling-water design.
Two-thirds have pressurized-water reactors that operate at higher temperatures and pressures, including FirstEnergy Corp.'s Davis-Besse nuclear plant in Ottawa County.
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