But officials with the Oyster Creek plant say it won't have any impact on the electrical service it provides.
The plant automatically shut down without incident at 3:42 a.m. Sunday when the fault was detected. The turbine control system is located on the plant's non-nuclear side, and technicians were working to repair and test it before the system was returned to service.
Oyster Creek is located about 60 miles east of Philadelphia. It generates enough electricity to power 600,000 homes, or roughly all the homes in Monmouth and Ocean counties combined.
The plant's operators have said it will close in 2019. The final refueling outage is planned for 2018.