Unit 2 of the Cook Nuclear Plant is back in service. Indiana Michigan Power brought it back online just before 1 a.m. today after a brief forced outage which began around 8:30 Sunday morning. The reactor was taken offline after operators noted a gradual decline in performance of both of the unit’s two non-essential service water pumps. That water is used to maintain cooling for the main turbine’s lube oil system and other non-nuclear and non-safety-related systems. A system inspection determined the problem was the pump strainers had become clogged by debris from Lake Michigan. Those parts were cleaned, inspected again, and put back into service. Officials say the decision to take the unit offline was “conservative” in order to ensure a safe and controlled shutdown. Unit 1 stayed at full power.
