TIVERTON, Ont. - Damage to some non-nuclear equipment at the Bruce Power complex in southwestern Ontario will delay putting one of its refurbished units back into service.

Bruce Power said Friday that inspections this week determined repairs were needed at an electrical generator on the non-nuclear side of the plant, which is located on the eastern shore of Lake Huron near Tiverton, Ont.

The nuclear power company said the issue was identified last week just before the Unit 2 reactor at the Bruce A generation station was to be reconnected to the provincial power grid.

Other work at Bruce A is going ahead as planned. Unit 3 is expected to return to operations within days after being shut down in November for $300 million of improvements that are expected to add a decade to its life.

Unit 4 of Bruce A is already operating and Unit 1 is on track to return to service this summer.

A part-owner of the facility, TransCanada Corp. (TSX:TRP), said it doesn't expect the delay at Unit 2 -- which has been out of service since the mid-1990s -- will affect the overall cost of the overhaul.

"In the lead-up to synchronizing Unit 2 to the electrical grid, an incident occurred in the generator system that caused some damage," TransCanada said.

"An analysis of the situation is underway and will be followed by a plan that details a repair schedule and updated timelines for an in-service date. This will likely mean Unit 2 will not be synchronized to the Ontario electrical grid as previously stated in Q2 2012."

"Refurbishment of the Unit 1 reactor at Bruce Power is progressing as planned and it is expected to begin commercial operations in mid-third quarter 2012 as previously disclosed."

Bruce Power is jointly owned by Calgary-based TransCanada, Saskatoon-based uranium producer Cameco Corp. (TSX:CCO), the OMERS pension fund and two unions representing some employees at the plant.

The power plant has two generating stations, Bruce A and Bruce B, each with four nuclear reactors. Six of the reactors are currently operating and producing 4,700 megawatts of electricity.