Downed reactors spark power crunch

TORONTO, ONTARIO - A series of breakdowns at Bruce Power's nuclear reactors contributed to a power emergency April 7 that forced officials to reduce voltage across the system and to import emergency power.

Critics said the outages show the power grid is fragile, but Energy Minister Dwight Duncan dismissed the fears.

Unit 6 at Bruce Power's station near Kincardine was forced out of service due to problems with the heat transport system that carried heat from the reactor core to its steam generator. Unit 5 had been forced out of service Wednesday, while Unit 3 had been forced out of service April 2 for valve repairs.

A fourth reactor, Unit 4, was already shut down for planned maintenance, leaving only two of Bruce Power's six operating reactors in service.

Meanwhile, three nuclear reactors operated by Ontario Power Generation are also out of service.

As a result, seven of Ontario's 15 functioning reactors were out of commission, removing more than 5,000 megawatts of generating capacity from service. A coal-fired plant at the Lambton plant near Sarnia also broke down April 7.

OPG has two reactors out of service for planned maintenance — one at Darlington, one at Pickering. A third, the recently restarted Pickering 4 unit, came out of service April 2.

OPG spokesman John Earl said staff had noticed thinning in the metal of feeder pipes in the station's Unit 1, which is being refurbished. They decided that pipes in Unit 4, which is about the same age, should also be inspected.

To spread the available power more thinly across the system, operators were forced to reduce voltage by 5 per cent — the maximum permitted — giving the power grid the equivalent of an extra 400 megawatts of generating capacity.

The Independent Electricity System Operator was also forced to import electricity from the United States.

The breakdowns came at a lucky time. Demand is lowest during the spring and fall, when there's low demand for electricity to heat or cool buildings.

Electricity demand peaked at less than 20,000 megawatts April 7. On a very cold or very hot day, demand can exceed 25,000 megawatts.

But the failures served as a warning to anyone who feels complacent since the blackout of 2003, said Tom Adams, executive director of Energy Probe. "It just shows how fragile the system is, and (it's) getting more fragile all the time," he said.

Duncan downplayed the severity of the problem, saying the situation was "nowhere near blackout."

"I think fragile is too strong of a word," her said. `` I would characterize it as saying our reserves are lower than we like. We like to have about a 20 per cent reserve and it went lower than we like, and the imports made up for that." NDP leader Howard Hampton said the power shortage is further proof Ontario's supply of electricity is in trouble.

"This is a mild day, it's not a cold day in January, it's not a hot day in August. What it shows is the McGuinty government really doesn't have a plan for electricity supply in this province."