The company has identified the problem in the sprinkler during testing and reported it to the NRC, reports AFP.
A problem has been identified in the piping that supplies water from the Mississippi River to the sprinkler system in case of a fire in the building.
Xcel Energy is continuously monitoring the system and is cleaning the sprinkler system piping and expects to restore the system to service by the end of this week.
NRC and the company reported that there are no immediate safety concerns at the plant.
