A U.S. appeals court has rejected an argument by the state and an anti-nuclear group that the Entergy Corp.'s Vermont Yankee nuclear power plant should not have been given a new operating license because its federal water quality permit was out of date.

In a ruling issued Tuesday, the U.S. Court of Appeals for the District of Columbia said the state had multiple opportunities to argue the Vernon plant lacked a valid permit under the Clean Water Act during the proceedings that led up to the plant's relicensing last year. It said the state and its ally, the New England Coalition, failed to do so forcefully enough.

They raised the water quality issues before a Nuclear Regulatory Commission review panel known as the Atomic Safety and Licensing Board but did not do so after the board issued a preliminary decision in favor of Entergy in 2008, the court said.