The Nuclear Regulatory Commission is investigating a hydrogen gas leak that has shut down the Millstone Unit 3 nuclear reactor.
The NRC says the leak occurred on Sunday morning in a turbine building at the Connecticut plant, and workers responded by manually shutting down the reactor.
Neil Sheehan, a spokesman for the Nuclear Regulatory Commission, told The Day of New London that the leak occurred after a sealant plug for hydrogen in the main generator came lose and workers successfully vented out the hydrogen.
The reactor recently returned to operation after a scheduled outage for refueling.
The NRC said it is trying to determine whether the leak may have been related to work done during that refueling.