AEP’s Cook Unit 1completes shortest refueling outage in its history

AEP’s Cook Unit 1completes shortest refueling outage in its history

Indiana Michigan Power’s Cook Nuclear Plant Unit 1 returned to service at 7:59 a.m. Oct. 24 completing the shortest refueling outage in the 40-year history of the plant. The 30-day, eight-hour refueling shutdown bested the previous record of 31 days 17 hours set in 2005. There were no OSHA Recordable Injuries recorded by the more than 4,000 people working at various times during the outage.

In addition to refueling the reactor and performing regular maintenance and testing work, the current outage also included several Life Cycle Management (LCM) projects. In 2005, Cook received license renewals from the Nuclear Regulatory Commission that will allow the two units to run to 2034 and 2037 respectively. That is an additional 20 years beyond their original licenses. The new license takes effect for Unit 1 on October 26.

Cook Unit 1 is now also fully compliant with all upgrades and modifications required by the Nuclear Regulatory Commission as a result of the Fukushima nuclear accident in Japan. It is one of the first nuclear units in the country to complete all that work.

The NRC required that U.S. facilities install additional instruments to monitor used fuel storage pools and develop strategies to prevent damage from the loss of all onsite and offsite power. The new equipment ranges from diesel-driven pumps and electric generators to ventilation fans, hoses, fittings, cables and communications gear.

Cook has a new earthquake- and tornado-proof building on site to house the back-up equipment. There is another layer of back-up equipment at national response centers in Memphis and Phoenix that can be deployed within 24 hours.

Cook Unit 2 remained at 100 percent power during the refueling. That unit has also completed the last two fuel cycles at full capacity.

One of the LCM projects this outage was the replacement of two 58-ton feedwater heaters that pre-heat water before it enters the Steam Generators. Steam passes around 2,915 five-eighth inch U-tubes that run the length of the 41 foot shell. There is also a new digital control system. The plant was not originally designed to replace these large components so some significant structural adjustments were made to accommodate the replacement.

Over the course of the outage, about 2,500 contracted workers supplemented the regular 1,198-person plant staff. More than 10,000 maintenance, inspection and equipment modification job activities totaling more than 268,000 work-hours were scheduled for two daily 12-hour work shifts throughout the outage.

At full capacity, the 1,030-net MW Unit 1 and 1,077-net MW Unit 2 combined produce enough electricity for more than one and one half million average homes.

Indiana Michigan Power is a wholly owned subsidiary of American Electric Power (NYSE:AEP).