MONTPELIER, Vt. (AP) – A fire in a transformer at the Vermont Yankee nuclear power plant caused the plant to declare an unusual event Friday, the lowest level of emergency, officials said.

The fire was detected just before 7 a.m. and the nuclear reactor was automatically shut down, said plant spokesman Rob Williams.

There was no release of radiation and no injuries, he said.

Williams said shortly after 9 a.m. that the fire had been extinguished, but that the unusual event status continued.

“There is a deluge system that activated and the local fire departments were called in,” Williams said. “Since the fire lasted longer than several minutes, by procedure we declared an unusual event.”

As part of the plant’s emergency procedure, officials in Vermont, New Hampshire and Massachusetts were notified, Williams said.

The plant is located in Vernon, in Vermont’s southeast corner. Its emergency evacuation zone extends into the other two states.

The transformer that caught fire is on the plant’s non-nuclear side, Williams said. It is used to step-up the voltage of the electricity generated at the plant so it can be transmitted efficiently.

It was unknown how badly the transformer was damaged, and Williams said he could not estimate when the plant might be back on line again.

Friday’s incident was the latest in a string of bad news for Vermont’s lone nuclear plant, which began operations in 1972 and is seeking permission from regulators to boost its power output by 20 percent above its current 540-megawatt capacity.

In April, about 20 cracks were discovered in the plant’s steam dryer. That’s a component that has been prone to cracking at other plants that have increased their power output. The steam dryer cracks at Vermont Yankee were discovered while that plant’s power boost request was still pending.

Later the same month, two highly radioactive fuel rod segments were discovered missing from the plant’s spent fuel storage pool, where they had been thought to have been in storage since 1980.

The missing fuel has not been found, but officials with the federal Nuclear Regulatory Commission have said it is very unlikely that it could be at large among the public. A more likely scenario is that the fuel rod segments were mistakenly included in a load of low-level radioactive waste sent to a special disposal facility.

AP-ES-06-18-04 0950EDT