Bruce Nuclear generator back in service

- One mothballed nuclear generating unit has returned to service, but a second that returned to service in September has hit a short-term problem.

Unit 4 of the Bruce A nuclear station has been running at close to 90 per cent capacity in early November, according to information from the Independent Electricity Market Operator, known in the industry as IMO.

The unit, which was removed from service in 1997, has been delivering up to 690 megawatts of power to the province's electricity system.

While the Bruce unit is operating, a unit at the Pickering A nuclear station that returned to service in September from a six-year layoff has had to be shut down.

The difficulty is an "unscheduled equipment outage of short-term duration," according to John Earl, a spokesperson for Ontario Power Generation, or OPG, which owns Pickering A. The unit should be back in service soon, he said.

Bruce Power, which operates the Bruce station under lease from OPG, has said it hopes to restart a second unit at the Bruce A plant within weeks of returning Unit 4 to service. An outlook prepared by the IMO shows the second unit returning within a month of Unit 4.

An assessment released recently by the North American Electric Reliability Council says that, with the nuclear reactors returning to service, the power supply should be adequate to meet Ontario's needs for the coming winter.

If the generators don't restart, however, Ontario might have to rely heavily on imports, the council warns, especially if weather is severe. In addition, some generators might have to delay scheduled maintenance shutdowns.

Unit 4 has suffered some unexpected delays. Bruce Power had hoped to get the unit running by the end of April to sell into the peak summer electricity market.

But a series of setbacks delayed the restart until early October. At that point, restarting the reactor was subject to rules set by the Canadian Nuclear Safety Commission, which required safety checks as the unit was slowly brought up to power.

That was followed by a standard test of the shutdown system, which stopped the reactor once more and began the restart process all over again.

Pickering A has suffered its own share of misery.

The first of four reactors was supposed to be back in service nearly three years ago, and the refit is $1 billion over budget.