Canadian-designed nuclear reactor design flaw discovered

January 10, 1997

Canadian-designed Nuclear Reactor Design Flaw Discovered as Prime Minister Peddles Nuclear Technology in Southeast Asia

Prematurely thinning pipes could force nuclear plant into costly repairs or early shutdown

Engineers at a nuclear plant in eastern Canada have discovered a serious flaw in the Canadian-designed reactor that could cost millions of dollars to repair or force government-owned New Brunswick Power, to cut short the life of the plant.

According to a report produced by New Brunswick Power for the Atomic Energy Control Board, the federal nuclear safety regulator, routine measurements identified the problem. Coolant-carrying pipes, which take superheated heavy water from the reactor core to the steam generators are corroding much faster than expected.

According to local press reports, officials now doubt whether the pipes will last the full 30-year lifespan of the plant.

The 630 MW Point Lepreau plant, which was once considered a flagship for the Canadian nuclear industry, located in the province of New Brunswick, is only 13 years old. Planners justified its Cdn$1.4 billion construction cost assuming that the plant would produce power at 80 per cent capacity for 30 years. For the last two years, the plant has produced at less than 50 per cent capacity.

When the plant is running, Point Lepreau supplies the province with one-third of its total electricity supply. If shut down now for repairs, New Brunswick Power faces replacement power costs of $350,000 per day.

Over the past two years, the plant has been plagued with technical problems and was shut down for eight months in 1995 for repairs. According to an official with the Atomic Energy Control Board, no one is sure how many feeder pipes are affected — there are 760 pipes but only about 12 pipes have been checked. Due to the location of the pipes right next to the reactor core, the problem can only be monitored when the plant is shut down. Until the discovery of wall thinning was made, the next planned shut down was not scheduled to begin for several months.

Scientists and engineers are now scrambling to determine the cause of the rapid corrosion in the hope of finding a way to stop it. Iain Lee of the Atomic Energy Control Board said there is evidence of similar problems at other aging Candu reactors across the country but he was not aware if the problem was noticed at Candu reactors sold to other countries.

Prime Minister Jean Chrétien left this week for southeast Asia as part of a 400-member trade delegation that includes representatives of Canada’s nuclear industry vying for Candu export deals in South Korea, Thailand, and the Phillippines. Canada has sold Candu reactors to India, Pakistan, Argentina, Romania, and South Korea. In November last year, Canada sold two reactors of the Point Lepreau design to China.


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