BRIDGMAN, Mich. - Both of American Electric Power’s (NYSE: AEP) Cook Nuclear Plant units are projected to be back on-line by the end of September. Unit 1 will return first, with Unit 2 following about one week later.

AEP has determined that silt intrusion that resulted in the shutdown of Unit 2 on Aug. 30 will require cleaning and flushing of several plant components along with repair of a discharge strainer on the plant’s service water pumps. The pump discharge strainer degradation resulted in a build-up of zebra mussel shells, which in turn, contributed to the silting issue.

Unit 1 was taken off-line Aug. 27 to replace a circulating water pump discharge valve, but both units are affected by the silting issue. The valve has since been replaced.

“Our team has done a great job through the holiday weekend identifying the causes of the silt intrusion and required repairs,” said Bob Powers, senior vice president - nuclear generation. “There’s known scope for maintenance and some enhanced instrumentation to install, but we have an identified path for the safe return-to-service of both units.”

American Electric Power is a multinational energy company based in Columbus, Ohio. AEP owns and operates more than 38,000 megawatts of generating capacity, making it America’s largest generator of electricity. The company is also a leading wholesale energy marketer and trader, ranking second in the U.S. in electricity volume with a growing presence in natural gas. AEP provides retail electricity to more than 7 million customers worldwide and has holdings in the U.S. and select international markets. Wholly owned subsidiaries are involved in power engineering and construction services, energy management and telecommunications.