THIS STORY HAS BEEN FORMATTED FOR EASY PRINTING

Shutdown at Pilgrim plant was result of human error

Regulatory commission sends team to investigate

By Travis Andersen and Beth Daley
Globe Staff / May 14, 2011

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The Nuclear Regulatory Commission is sending a special inspection team to Pilgrim Nuclear Station Monday morning to analyze the human error that caused the Plymouth plant to automatically shut down Tuesday.

The plant was restarting this week after a scheduled, routine monthlong stoppage for refueling and maintenance when operators realized the reactor was heating up faster than expected, according to Neil Sheehan, a spokesman for the regulatory commission. To better manage the reactor, operators began manipulating its control rods, but a computer sensed a problem and automatically shut down the plant, he said.

“It appears initially they did not have a good handle on the heat power levels,’’ said Sheehan, adding that inadequate training was probably a factor.

Carol Wightman, a spokeswoman for Louisiana-based Entergy Corp., which runs the plant, confirmed in an e-mail that human error caused the shutdown but declined to say what actions, if any, were taken against those responsible.

Representative Edward J. Markey’s office, however, said it had confirmation from the regulatory commission that four operators were suspended.

Wightman said the plant was operating at 13 percent of its capacity last night but could not predict when it would return to full power. She also said the plant will conduct its own review.

Pilgrim and other US nuclear plants have come under increasing scrutiny following the ongoing Japanese nuclear crisis.

Pilgrim has the same basic design as the most compromised nuclear reactor in Japan, including the way spent fuel rods are stored. Critics, including Attorney General Martha Coakley, have said spent fuel pools at Pilgrim could one day suffer loss of coolant, leading to radioactive release of the kind ongoing in Japan.

Markey, a vocal critic of the nuclear industry, said he was troubled by the shutdown.

“The events of the week — both at Pilgrim . . . and in Japan, which has confirmed a meltdown in a second reactor — serve to highlight the need for the Nuclear Regulatory Commission to suspend all of its licensing decisions until a thorough environmental analysis and safety upgrade can be undertaken.’’

Mary Lampert, director of Pilgrim Watch, an organization opposed to Pilgrim’s pending relicensing application, said by phone that she thought the shutdown was caused by careless workers rushing the refueling process.

“There is a rush to finish so that they can generate electricity and money,’’ Lampert said.

Wightman disputed that, saying Pilgrim did many other things during the monthlong outage, including maintenance work on generators and replacing rod drives and rod blades.

“Whenever you do major maintenance, there is a slow, deliberate and, controlled process of restarting the plant,’’ she said.

Sheehan said the plant experienced an unexpected pressure differential yesterday in systems that help prevent radioactive release. That problem is probably preventing the plant from operating at greater than 15 percent.

Wightman said Pilgrim was investigating the problem.

“There is no danger to the public as a result of this differential in pressure,’’ she wrote.

Beth Daley can be reached at bdaley@globe.com; Andersen at tandersen@globe.com.