Cook Nuclear Plant operators had to double clutch the return to service for Unit 2 at Bridgman thanks to a malfunctioning valve earlier this week, but now that the issue has been resolved, the 67-day refueling outage is officially complete and the unit is back online.
According to Cook Plant officials, the Indiana Michigan Power facility originally completed its refueling outage at 12:28 am back on Monday, May 7. However, the unit had only been connected to the transmission grid for about three hours when a valve in the turbine steam system malfunctioned, and plant operators had to take the unit back offline for repairs.
The malfunctioning valve was repaired and the unit was again returned to service this morning, Friday, May 11th, at 3:40 am. The refueling outage lasted 67 days.
In addition to refueling the reactor and performing regular maintenance and testing work, the outage was extended due to the planned inspection and replacement of baffle bolts, which support internal components of the reactor vessel.
Joel Gebbie is Senior Vice President & Chief Nuclear Officer for the Cook Plant. He says, “The completion of several major projects this outage means the bulk of the Life Cycle Management work for Unit 2 is complete and the unit is well-positioned for long-term viability.” Gebbie adds, “The baffle bolt replacement was completed with record-low radiation dose and is now resolved for Unit 2. Now we look forward to another fuel cycle of the extremely high reliability we’ve seen for both Cook units over the past several years.”
All of the original large components on the secondary (non-nuclear) side for Unit 2 have now been replaced. A new 230-ton main generator rotor was installed this outage in addition to the four turbine rotors that were installed during the last refueling outage. Two high-pressure feedwater heaters were installed, and now all six original heat exchangers have been replaced. The three heater drain pumps were replaced this outage, and new digital reactor control instrumentation replaces the original analog system.
Prior to the refueling outage, the unit operated for 423 consecutive days at a capacity factor of 97.9-percent. That was the first time both of Cook’s two units completed breaker-to-breaker outages back-to-back. Running continuously between refueling outages is known in the industry as a breaker-to-breaker run as the unit’s output circuit breakers remained connected to the transmission grid for the entire 18-month fuel cycle.
About 1,500 contracted workers supplemented the regular 1,200-person plant staff during the outage. Those contract workers are now off to other projects until the next refueling stage.
At full capacity, the 1,084-net MW Unit 1 and 1,194-net MW Unit 2 combine to 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.
