Reactor is shut down at Comanche Peak nuclear plant

Nov. 03, 2012

Fort Worth Star-Telegram

One of the two reactors at the Comanche Peak nuclear power plant near Glen Rose was shut down early Friday after a cooling pump overheated, the operator reported.

According to an event report filed with the Nuclear Regulatory Commission, Unit 1 was shut down manually at 1:42 a.m. because of "high temperature indications" in a motor bearing on one of four huge pumps that circulate cooling water around the reactor.

An alarm that warns of an improper level of oil for the pump also sounded, the report stated.

Dallas-based Luminant Generating, the plant’s operator, is "currently looking into a cause" of the pump problem, spokeswoman Ashley Barrie said.

The reactor had to be shut down to remove the pump for servicing, she said.

Luminant is "developing a maintenance plan to resolve the issue. We anticipate returning the unit to service as soon as this work is completed," Barrie said.

Arjun Makhijani, president of the Institute for Energy and Environmental Research and a critic of using nuclear power to generate electricity, said that "anytime you manually shut a reactor down, it’s a big deal."

Although the sequence of events described in the NRC report sounded like the correct action, he said, "a manual trip is a nonroutine safety event."

Barrie said, "There was never any safety issue at the plant."

The Unit 1 reactor also experienced an unusual event Wednesday morning when a backup generator started unexpectedly. According to an NRC event report, a faulty power supply "was identified and further investigation/calibration will determine if other conditions contributed to the fault."

Barrie said, "The equipment malfunction that occurred on Wednesday is in no way tied to the manual trip" on Friday. The equipment that started the generator was replaced "and verified satisfactory through testing," she said.

Together, Comanche Peak’s two reactors can produce 2,300 megawatts of electricity. They are among the nation’s newest nuclear power plants, with Unit 1 going into operation in 1990 and Unit 2 in 1993, according to Luminant.

Unit 2 had been down several weeks for refueling and had just returned on line Friday morning, Barrie said. Nuclear reactors are typically refueled every 18 months, generally in spring and fall when temperatures are moderate and electricity demand is light.

Robbie Searcy, spokeswoman for the Electric Reliability Council of Texas, which operates the state’s largest power grid, said Unit 1’s sudden loss triggered automatic responses by big industrial users that agree to have their power interrupted to accommodate such events. ERCOT then calls on standby generators to replace the power the Comanche Peak unit had been providing to the grid.

It was fortunate Unit 1 went down in the early morning, when demand is especially low, Searcy said.

Jim Fuquay, 817-390-7552

Twitter: @jimfuquay

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