Mussels blamed for reactor shutdowns

16 November 2007

[Newshouse News Service, 12 November] Non-native mussels in Lake Ontario have cost Entergy between $1.5 million and $2 million per day in lost revenue by eating the wrong seaweed. Entergy's James A FitzPatrick nuclear power plant in New York state has been shut down three times in the past two months due to seaweed in cooling water taken from Lake Ontario clogging filters. Non-native zebra and quagga mussels that colonized Lake Ontario have been blamed for a surge in the amount of  Cladophora, a "filamentous algae" that grows in fine hairlike strands, in the lake. These mussels do not eat cladophora, but they do eat other types of floating algae, making the water clearer. This in turn has lead to the cladophora thriving as sunlight has been able to penetrate to greater depths. The mussels also excrete phosphorus and nitrogen, which fertilize the cladophora. The seaweed becomes a problem in late summer and early autumn when it dies back and winds can make the water choppy, raising the weed from the bottom of the lake. The FitzPatrick plant is making changes to its water intake and filtering system to prevent future problems with the weed. Universities also plan to study the problem next year. Other nuclear power plants on the shores of Lake Ontario, such as Nine Mile Point and Pickering, have not been affected by the problem as their water intake systems have been upgraded.

Further information

Entergy Nuclear