Nuclear Unit Shuts Down After Fire

A reactor at the Diablo Canyon nuclear power plant near San Luis Obispo shut down automatically Monday after a fire broke out, releasing steam but no measurable radiation into the air, officials said.

Breck Henderson, a spokesman for the U.S. Nuclear Regulatory Commission in Arlington, Texas, said the incident posed no threat to neighbors of the power plant. Henderson said the Diablo Canyon plant is “one of the best safety performers” in the regulatory region that includes all plants west of the Mississippi River.

The incident began at 12:25 a.m., when a fire occurred in an electrical room of the Unit 1 turbine generator building, where the steam from the reactor is converted into power. No one was injured, and plant workers put out the fire with a hand-held extinguisher within 30 minutes, said Bill Roake, a spokesman for Pacific Gas & Electric Co., which owns the plant.

The reactor shut down automatically, and operators declared an “unusual event,” the lowest-level alert under Nuclear Regulatory Commission rules. The last such incident at Diablo Canyon was two years ago, when a mudslide closed a road near the plant.

The cause of the fire was not immediately known. Two resident inspectors from the commission are investigating, Henderson said.

Roake said the reactor will not be restarted until the cause of the blaze is understood. The commission said all reactor systems functioned properly during the incident.

Electrical service to customers was not disrupted, Roake said. Each of the two reactors can supply 1,100 megawatts of power, or enough to meet the needs of 1.1 million customers.

Peg Pinard, chairwoman of the San Luis Obispo County Board of Supervisors, said first reports of the incident were worrisome, but she emphasized that residents were reassured by later accounts showing no detectable release of radiation.