The leak occurred in a pipe that connects the steam generator to the turbine of the Unit 2 reactor at Point Beach, said Maureen Brown, a spokeswoman for Hudson-based Nuclear Management Co.

The leak was detected Friday afternoon, Nuclear Management Co. told the Nuclear Regulatory Commission. The reactor was shut down at 8:18 p.m. Friday so that repairs could be made.

The two-unit Point Beach plant generates 1,036 megawatts of electricity and is owned by Milwaukee-based Wisconsin Energy Corp. Hudson-based Nuclear Management Co., a company that runs reactors for utilities, operates the plant.

The leak was detected in the secondary, or non-nuclear, part of the plant. Nuclear-plant operating standards required that the reactor be shut down before the repairs could begin.

"This is an issue where we identified something that needed to be corrected and we took the unit offline to make those repairs," she said.

It was unclear how long the reactor will remain out of service. Nuclear Management doesn't comment on when reactors will restart, Brown said.

The Point Beach repair comes while Wisconsin's other nuclear plant, Kewaunee, is shut down for refueling and inspections. During the Kewaunee shutdown, which began Oct. 9, contractors are replacing the vessel head cover at a cost of $20 million.

The Point Beach Unit 1, which was shut down last spring for refueling, inspections and repairs, remains operating at full power, the Nuclear Regulatory Commission said.