A federal appeals court today asked for additional briefing after hearing arguments over whether the Nuclear Regulatory Commission should have required the operator of the controversial Vermont Yankee nuclear plant to obtain Clean Water Act certification before the agency approved a 20-year license extension.

The state's Department of Public Service and the New England Coalition, an anti-nuclear group, say NRC was required to obtain a new water quality certification from the state as mandated under Section 401 of the Clean Water Act.

By failing to do so, the commission's decision in March last year to extend Entergy Vermont Yankee LLC's license -- an unpopular move in the state -- was invalid, the challengers say. Without the extension, the plant would have closed on March 21 this year.

But after today's argument before the U.S. Court of Appeals for the District of Columbia Circuit, the three-judge panel asked for the parties to file briefs on a related question: whether Vermont's ongoing consideration of whether the plant can renew its separate Clean Water Act permit -- as required under Section 402 of the statute -- has any bearing on the 401 certification.

The question has relevance to one of NRC's arguments: that no separate certification was required because the Section 402 permit can be interpreted as taking care of the Section 401 obligations, too.

The judges appeared troubled when the state's attorney, Elizabeth Miller, who is the commissioner of the Department of Public Service, pointed out toward the end of the argument that the 402 permit is currently in the process of being renewed by the state's Agency of Natural Resources.

That prompted the judges to ask a flurry of additional questions about what would happen, for example, if Vermont declined to renew the permit.

As the question had not been briefed, NRC attorney Sean Croston did not have a definitive response.

"I'm not fully sure about the answer to that question," he said. Croston speculated that NRC would then have to revisit the license renewal.

The judges conferred, and Judge Karen Henderson then asked for the parties to file briefs within 10 days.

"We want to get it as clear as possible," she said.

Patrick Parenteau, a professor at Vermont Law School, said the Section 402 permit renewal process -- which the school's environmental clinic is involved in on behalf of an environmental group -- is of key import.

That is in part because the state could, in theory, conclude that Entergy used a closed-cycle cooling system to address concerns about the temperature of the plant's water discharge.

"They seem to be seriously examining that," Parenteau said.

It would be an expensive proposition for Entergy, which could even be tempted to walk away altogether, he added.

The rest of the argument did not go so well for the challengers.

A major issue appears to be whether the court will dismiss the case on the grounds that it is before the court prematurely. That's because, both NRC and Entergy claim, the challengers did not exhaust their administrative remedies before the agency.

Judge Merrick Garland seemed particularly concerned that the petitioners didn't seek clarity from NRC before going to court.

"I don't understand why you didn't have to ask the NRC first," he said.

Today's case is separate from the dispute in federal court over whether Vermont has authority to shut down the plant altogether.

In that case, a federal judge ruled against the state in January (Greenwire, Jan. 20). The decision is now on appeal.