Cook Unit 2 reactor back in operation

By Tony Wittkowski | Business Reporter | The Herald-Palladium

BRIDGMAN — The Unit 2 reactor at the Cook nuclear power plant was up and running again Monday night after being down since late September for a planned refueling and maintenance outage.

Indiana Michigan Power’s Cook plant completed its refueling at 7:20 p.m. Monday allowing its Unit 2 reactor to reconnect to the transmission grid.

In addition to refueling the reactor and performing regular maintenance and testing work, the outage was extended due to the replacement of the main turbine and the inspection and replacement of baffle bolts, which support internal components of the reactor vessel.

The outage lasted 89 days.

Replacement of the high-pressure turbine and all three low-pressure turbines is the largest of Cook’s Life Cycle Management projects.

The $250 million turbine replacement has been in the planning stages for more than five years.

Originally, plans called for the reactor to be gaining in power and connected to the electric grid by late December.

However, an unexpected snag occurred as problems with defective fuel pump injectors for emergency diesel generators used as backup power supply for both Units 1 and 2 were discovered, plant spokesman Bill Schalk said.

“That caused about a week delay from the schedule as we were hoping to be up around Christmas Eve,” Schalk said Tuesday, “but it was a longer outage because of the baffle bolts and the turbine.”

The baffle bolt inspections were previously planned for 2019, but were moved forward based on industry initiatives following the discovery of degraded baffle bolts at two plants last spring.

Ultrasonic inspection was performed on all 832 bolts, and 201 bolts were replaced. Based on the inspections, AEP determined there was no impact on the safety of Unit 2 during the previous cycle of operation.

Cook’s Life Cycle Management includes 114 upgrade and replacement projects as part of the 20-year operating license extension granted by the Nuclear Regulatory Commission in 2005.

“Thanks to all our employees and local and regional craft workers for their safe and hard work during this longer than usual outage,” Joel Gebbie, senior vice president and chief nuclear officer, said in a news release. “We also appreciate the support of our families and the community as we work to secure the long-term viability and reliability of our plant.”

Additional baffle bolt inspections and replacements, and a potential design change to minimize stress on baffle bolts, may also take place in subsequent outages for both Cook units.

About 2,000 contracted workers assisted the plant’s 1,200 full-time employees during the outage.

At full capacity, both unit reactors at Cook combined are capable of producing enough electricity to power more than 1.5 million homes.

Contact Tony Wittkowski at or (269) 932-0358. Follow him on Twitter: @tonywittkowski.

(Author’s Note: This article was originally published on Jan. 4, 2017)


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