KINCARDINE, ON - Bruce Power returned to restarting two mothballed nuclear reactors after workers repaired a pump system early Tuesday morning.

Company spokesman John Peevers said "a valve or part of a valve" failed, leading to the leak. It was detected early Saturday morning. Crews isolated the problem and repaired it.

The Canadian Nuclear Safety Commission posted a statement on its website that says "there was no release to the environment and no plant worker received any dose (of radiation)...The other units in the Bruce A station were not affected."

On Monday, Peevers the setback "was not entirely unexpected. We are going to be heating up systems and starting up equipment that hasn't been operational for 17 years. We knew we were going to hit some bumps along the road. That's why we're taking a slow, steady, safety-first approach."

On Friday, Bruce Power received permission from the CNSC to remove the reactor shutdown guarantees on the Unit 2 reactor, which allowed the company to start it up for final checks before bringing it online.
When it's fully operational and online, the Unit 2 reactor will be capable of producing enough electricity to power 500,000 homes.

There is no timeline for Unit 2 to be fully operational, Peevers said.

When the Unit 1 and 2 restart project was originally announced in 2005, the cost of the program was estimated at $2.75 billion, with electricity production to begin by late 2009 or early 2010.

The cost has risen to $4.8 billion.

The power plant is located about 240 km northwest of Toronto on the eastern shore of Lake Huron.