The long-awaited restart of Bruce Power’s Unit 2 at Bruce A on Friday was delayed again for months after an issue was identified within the electrical generator on the non-nuclear side of the Ontario plant just an hour before synchronization with the grid was scheduled to occur.

The unit was producing steam for the first time in 17 years and operating per plan in the lead-up to generating power, but in the lead-up to synchronizing Unit 2 to the electrical grid, “an incident” on the non-nuclear side of Bruce’s operations occurred in the generator system that caused “some damage.”

“The electrical generator protection worked as designed and the approach to connect to the grid was stopped. This generator, common to all power plants, had been upgraded as part of the refurbishment project by Siemens Canada,” said Bruce Power, which is a partnership comprising Cameco, TransCanada, Borealis Infrastructure, The Power Workers’ Union, and The Society of Energy Professionals.

An analysis of the situation is under way 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,” said TransCanada in a statement on Friday.

Bruce Power received authorization from the Canadian Nuclear Safety Commission this March to power up the Unit 2 reactor, effectively ending the construction and commissioning phases of the project. Bruce Power consists of two generating stations (Bruce A & B) with each station housing four nuclear reactors. Six of those reactors are currently operational, accounting for a total capacity of more than 4,700 MW.

Refurbishment of the Unit 1 reactor at Bruce Power is progressing as planned, and it is expected to begin commercial operations in the mid-third quarter of 2012. Unit 3 is also expected to return to operations this week following the completion of an outage that started in November 2011, during which Bruce Power made a C$300 million investment to extend the life of the unit by another decade. Bruce Unit 4 continues its record run, the company said.

“While this is clearly seen as a setback, with this repair isolated to one non-nuclear system on Unit 2, we can continue to advance the Unit 1 work program,” said Mike Burke, vice-president Bruce A operations. “We shouldn’t lose sight of the fact that, in parallel, Unit 4 continues its record run, which is approaching 500 days of continuous operation, and Unit 3 is coming back from a major investment outage that will extend its life by up to 10 years. This strong performance, combined with our Bruce B units, will ensure continued system reliability in the province.”

Once the refurbishment is complete, Bruce Power will be one of the world’s largest nuclear facilities, capable of providing more than 6,200 MW, or about 25% of Ontario’s power.

The Unit 2 delay “will not have an impact on Ontario’s electricity system reliability due in part to the strong performance of Bruce Power’s operating fleet, nor is it expected to materially change the cost of the Restart Project.,” Bruce Power said. “Ontario ratepayers will not be impacted as Bruce Power accepted project risk over C$3.4 billion in July 2009, through its agreement with the Ontario Power Authority (OPA).”

Sources: POWERnews, Bruce Power, TransCanada