MINERAL, Va. (AP) - Dominion Energy has shut down one of its two nuclear reactors at the North Anna Power Station after the company says a "very small water leak" was discovered in the cooling system.

Dominion spokesman Rick Zuercher told The Richmond-Times Dispatch (http://bit.ly/2C5epTG ) that Unit 2 at the Louisa County station was taken out of service Sunday afternoon.

Dominion told its employees in an e-mail Monday that personnel identified the leak location involving an instrument that provides operators with information on the water level in the reactor.

The email says personnel are working to fix the problem, and that the unit will return to service soon.

Roger Hannah, a spokesman for the U.S. Nuclear Regulatory Commission, says the agency is allowing resident NRC inspectors at the facility to handle the issue.