NEWBURYPORT, MASS. -- "It's like you're winning the game with one minute to go and the referee says, 'Hold it, we're going to change the rules and go into overtime,' " said Tom Moughan, coordinator of Citizens Within the Ten Mile Radius, which opposes the nearby Seabrook nuclear plant in New Hampshire.

Moughan's frustration was typical of official and public reaction here to Thursday's decision by the Nuclear Regulatory Commission to consider licensing nuclear plants even if state and local officials do not approve evacuation plans.

Under a 1980 NRC regulation requiring state and local participation in utilities' evacuation planning within 10 miles of a plant, New Hampshire officials approved plans for 17 communities near Seabrook. But Massachusetts Gov. Michael S. Dukakis (D), in the wake of last year's nuclear disaster at Chernobyl in the Soviet Union, followed the lead of six Massachusetts coastal communities and refused to submit an evacuation plan.

Dukakis' action has delayed the licensing of the $5 billion Seabrook plant, which was completed in 1986 and, until Thursday, local officials hoped it might prevent licensing altogether. Massachusetts state Sen. Nicholas J. Costello (D), who represents five of the six communities, said the NRC's about-face "is like saying we can't win the game so we're going to change the rules."

The 1980 regulation was a response to the 1979 nuclear accident at Three Mile Island (TMI) in Pennsylvania. Since then, the five-member NRC has been reconstituted by the Reagan administration, with panel members considered more favorable to the nuclear power industry.

But officials at New Hampshire Yankee, the company that manages the Seabrook plant, said the rule was never intended to grant states the power to prevent a nuclear plant from opening.

"The NRC has a strong case in terms of interpreting the intent of Congress" when it directed the NRC to prevent recurrence of the confusion that followed TMI, said David Scanzoni, manager of corporate communications for New Hampshire Yankee.

Massachusetts Attorney General James Shannon Thursday vowed to sue the NRC. "This is going to end up in court," he said. "There's no doubt about that."

Meanwhile, New Hampshire Yankee has submitted to the NRC its own evacuation plan for the six Massachusetts communities.

Dukakis and local officials believe the plan will never work. Popular beaches in the area, a large amusement park and narrow roads all make any evacuation plan impractical, they said. "We have determined that no evacuation plan will protect the public," Dukakis has said.

The view from Long Island, N.Y., where the Shoreham nuclear power plant has been operating at 5 percent power, is much the same. Local officials last year refused to participate in an evacuation drill, underscoring their contention that safe evacuation would be impossible in a nuclear accident.

"The county of Suffolk is not antinuclear," assistant county executive Frank Petrone said. "This is not a referendum on the industry. It's about poorly sited plants and public safety. With this rule change, it is obvious to us that the NRC's interest is not in public safety."

Petrone resigned last year as regional head of the Federal Emergency Management Agency after refusing to alter a draft report questioning the agency's ability to certify Long Island's safe evacuation in case of a Shoreham accident.

He said that the NRC's rule change "may open the door for local governments to back out of their partnerships with utilities . . . . People in these communities {with nuclear power plants} may also wonder whether the NRC will in the future bend the rules or change them to suit their utility company."

Jane Alcorn, of Citizens Lobby Opposing Shoreham Evacuation (CLOSE), said Long Island's geography makes Shoreham inherently unsafe.

Special correspondent Marianne Yen contributed to this report.