Unexpected algae build-up shuts-down nuclear plant in Ontario, Canada

[Ian David]

An unexpected build up of algae on a lake-water intake system used for cooling has forced Ontario Power Generation to temporarily shut down one of its Pickering nuclear reactors until the fast-growing green muck is cleaned up. Experts say bad-smelling blooms of Cladophora algae are linked to warmer water temperatures and are likely to get worse as a result of global warming and high phosphorous levels caused by lawn fertilizers, agricultural runoff and detergents entering the lake. Zebra mussels, which didn't exist in Lake Ontario when the Pickering plant was built, also contribute to the problem by filtering the lake water so much that it's easier for the sun to shine through. More sunlight results in more algae growth.

"Recent hot weather has resulted in an increased growth of algae in Lake Ontario," OPG said yesterday. "Wind and wave conditions ...have increased the flow of algae, causing a larger than normal amount of algae to enter the station's water intake systems." Algae builds up on screens and filters, reducing the flow of water that's necessary for cooling purposes. OPG spokesperson Bill McKinlay said Pickering B Unit 5 was shut down so that water flow can be diverted to units 6, 7, and 8 while the algae are removed. "It could take a few days, a couple of days maybe," said McKinlay, emphasizing that the shutdown of unit 5 has nothing to do with the reactor's maintenance outages last month and earlier this summer. "It's totally unrelated." This isn't the first time algae has disrupted the operation of OPG's nuclear fleet. Unit 1 at Darlington generating station had to be shut down briefly on Sept. 29, 2005 as a result of algae buildup, while units 5, 6, and 8 at Pickering B were taken offline on Aug. 19, 2005, because of a similar event. OPG estimates that Cladophora fouling of cooling water intakes has cost the company more than $30 million in lost power generation over the past 12 years.

As a result, the company installed a mesh barrier in the lake in May hoping to block the flow of algae by as much as 30 per cent. The effectiveness of the barrier will be studied over the year in collaboration with the University of Waterloo and the Durham region. OPG, in the environmental assessment report it recently filed to the Canadian Nuclear Safety Commission in relation to the possible refurbishment of Pickering B, said climate change and rising lake temperature could lead to increased algae and zebra mussel growth. "Temporary reactor power reductions could be required," the company said. "None of the potential effects associated with climate change are expected to pose any risk to workers, members of the public or the environment.")

More:
http://hisz.rsoe.hu/alertmap/woalert_read.php?lang=eng&cid=12840

[Dogmudgeon]

1. That wouldn't happen with a COAL plant, no sir!

--p!