NextEra keeps NH Seabrook reactor reduced for work

NEW YORK Nov 30 (Reuters) - NextEra Energy Resources LLC has kept the 1,245-megawatt Seabrook nuclear power station in New Hampshire at about 65 percent power since mid November due to a vibration in a low pressure turbine, a spokesman at the U.S. Nuclear Regulatory Commission said Monday.

The NRC spokesman could not say when the unit would return to full power but noted NextEra, a unit of FPL Group Inc FPL.N, was working with General Electric Co (GE.N) to fix the problem.

The unit exited a refueling outage in mid November. As the unit ramped up, the operator noticed torsional vibrations on one of the unit's three low pressure turbines. Torsion is the twisting of an object due to an applied torque.

Since the turbines turn at very high speed, the vibrations could damage the rotor, which the NRC spokesman said was about the size of a school bus.

Officials at Seabrook were not immediately available for comment.

The unit shut for the refuel on Oct. 1.

It last shut for refueling from about April 1-May 8, 2008 and is on an 18-month refueling cycle.

Seabrook is located in Seabrook in Rockingham County about 40 miles (64 km) north of Boston. (Reporting by Scott DiSavino; Editing by Marguerita Choy) ((scott.disavino@thomsonreuters.com; +1 646 223 6072; Reuters Messaging: scott.disavino.reuters.com@reuters.net)) ((For help: Click "Contact Us" in your desk top, click here [HELP] or call 1-800-738-8377 for Reuters Products and +1-888-463-3383 for Thomson products; For client training: training.americas@thomsonreuters.com; +1 646-223-5546))