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By the Numbers: D.C. Cook Nuclear Unit 1 Refueling Outage

June 2, 2022

The D.C. Cook Nuclear Plant, located in Bridgman, Mich., recently completed its refueling outage of Unit 1 on May 30 at 05:39 in the morning. The main purpose of a refueling outage is to replace older fuel in the reactor that is depleted and can no longer produce energy from nuclear fission reactions.

Thousands of employees worked 240,000 hours over 58 days during the refueling outage. But, the most important thing – everyone went home in the same or better condition than they arrived to work.

“It took a lot of people a lot of hours to complete this important refueling outage for our company and our community,” said D.C. Cook Nuclear Plant Manager Kelly Ferneau. “Thanks to their diligence and engagement in safety and human performance, Cook Plant will continue to run safely and reliably long into the future.”

Each unit at Cook Nuclear Plant enters a scheduled refueling outage once every 18 months. The planning and scope of work for each refueling outage is established years in advance to support the long-term reliability of this carbon-free baseload generation source. 

The outage begins with the operations staff shutting down the plant to stop the nuclear chain reaction and cool things down. Once the right conditions are established, workers begin the process to disassemble the reactor so the fuel can be removed from the reactor vessel and placed into storage in the spent fuel pool. After the fuel from the core is stored safely in the pool, a team of highly trained mechanics, technicians, and other craft workers begin the process of inspecting and refurbishing equipment that is important for the safe and reliable operation of the plant. When all the work is complete, approximately 80 new fuel assemblies are loaded into the reactor vessel along with fuel that was used over the last two cycles for a total of 193 fuel assemblies. 

Along with refueling the reactor, crews performed other regular maintenance, inspections, and testing work that can only be performed with the unit shut down. Outages are usually scheduled during the spring or fall, when power demand is typically low.

Refueling Outage By the Numbers:

  • Lasted 58 days, 2 hours and 39 minutes
  • 240,000 work hours recorded
  • More than 2,200 contractors and plant employees worked 12-hour shifts
  • Nearly 11,000 maintenance, inspection and equipment modification job activities conducted
  • One of the Unit’s four reactor coolant pump motors was replaced for routine refurbishment
  • Unit 1 operated for more than 12,500 hours during its last cycle at a capacity factor of 104 percent and generated 13,757,462 megawatt-hours of electricity --  enough electricity to power nearly 1.15 million typical homes that use 1,000 kilo-watt hours per months a year
  • At full capacity, the 1,084-net MW Unit 1 and 1,194-net MW Unit 2 combined produce enough electricity for more than one and one half million average homes

D.C. Cook Nuclear Plant Refueling Outage


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