Donald C. Cook Nuclear Power Plant in Michigan Remains in 'Hot Standby' Mode

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Researched by Industrial Info Resources (Sugar Land, Texas)--The Donald C. Cook Nuclear Power Station, which is located in Bridgman, Michigan, remains offline due to an unscheduled mechanical maintenance outage. The station is owned by American Electric Power Company (NYSE:AEP) (Columbus, Ohio).

Plant officials at Cook said that one of the two units was manually tripped offline by an operator on July 28, when the steam generator pressure dropped in the 1,107-megawatt (MW) Unit 2. The pressure level dropped in the steam generator due to low suction pressure in the west main feed pump.

After further investigation, officials learned that the feed water pump discharge valve to the generator did not function correctly, which caused the pressure level to drop. The affected discharge valve opened as expected during pump start, but the valve closed instead of throttling to the intermediate position after hitting a high flow demand.

The unit has remained in "hot standby" mode, during which the water temperature and pressure are brought to (or in this case remain at) normal operating levels. Plant officials have said that they hope to be able make the needed repairs and bring the unit back online no later than Wednesday night, July 31, as long as no other issues arise.

The Donald C. Cook Nuclear Power Station consists of two units that can generate more than 2,100 MW of electricity. The other unit, the 1,084-MW Unit 1, was not affected and remains online. Unit 1 continues to generate at full capacity.

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