The Cook Nuclear Power Plant shut down one of its reactors early Sunday morning after an equipment issue triggered an automatic safety response, plant officials said.

According to Cook Nuclear Plant Communications Manager Bill Downey, a processor connected to instrumentation that monitors one of the plant’s four steam generators in Unit 2 stopped functioning. That malfunction caused the reactor to automatically trip and shut down.

Downey said Unit 2 is currently offline but remains in a safe condition while operators and engineers investigate the cause of the failure and work toward restoring the unit.

“We basically put the unit in park,” Downey said, explaining that Unit 2 was taken off the electrical grid while crews address the issue. Once repairs are completed and the system is confirmed to be stable, the plant will begin the process of bringing the reactor back online.

Downey emphasized that the shutdown has not affected electrical service to the community. Unit 1 at the plant continues to operate normally, and there have been no power interruptions as a result of the incident.

He also said weather conditions were ruled out as a factor, despite extremely cold temperatures in the region. The investigation is focusing on electrical and instrumentation-related components connected to the processor that failed.

Downey said the plant will return Unit 2 to service once the problem is identified and corrected.