Dominion Pinpoints Unit 2 Reactor Leak

Dominion Pinpoints Unit 2 Reactor Leak

Jul 15 - McClatchy-Tribune Regional News - Patricia Daddona The Day, New London, Conn.

The Millstone Unit 2 reactor will remain shut down as operators fix a tiny leak located in part of the system that cools the reactor.

Originally, the reactor at the Millstone Power Station had been shut down since July 3 following an electrical storm that caused power fluctuations from the region's electrical grid and an automatic trip, or shutdown.

Then, on Monday, as operators were restarting the plant, they discovered a "very small" leak in a reactor coolant pump, Neil Sheehan, a spokesman for the Nuclear Regulatory Commission, said in an e-mail. Late in the afternoon Tuesday, the leak was still dripping and is slightly radioactive, but drains into a water collection area at the base of the building where it is captured, Sheehan wrote.

The reactor coolant system transfers heat produced in the reactor core to the steam generators. There, heat is produced for the turbine-generator, which in turn produces electricity.

By early evening, Dominion had pinpointed the problem.

"We have identified the location of the leak," said Dominion spokesman Rich Zuercher in an e-mail. "It is on piping that provides cooling to a reactor coolant pump seal. We are preparing to make the repair. We also performed an 'extent-of-condition' examination on other reactor coolant pump seal cooling piping and are taking appropriate actions to prevent the potential for a similar issue to develop."

While the reactor is idled, plant operators will fix the pipe. For competitive reasons, the company does not disclose how long the shutdown will last or when the reactor will come back online.

A pressurizer safety valve also failed to close properly and may have to be fixed, said Sheehan and Zuercher.

There was no danger from the leak to employees or the public, Sheehan and Zuercher said.

The Unit 3 reactor continues to function properly, they said.

Under normal conditions, Millstone generates 2,103 megawatts from its two working reactors -- enough electricity to power 500,000 homes, according to the company's Web site. Unit 2 began commercial operation in late 1975. The Unit 1 reactor was closed in 1998.