WASHINGTON--Gov. Michael Dukakis' chief aide on atomic power issues was dragged out of a Nuclear Regulatory Commission meeting yesterday after he tried to speak out while commission officials discuseed the possible reopening of a controversial Massachusetts reactor.

Peter Agnes, assistant Massachusetts public safety commissioner, stood up while NRC officials were telling commissioners that the Pilgrim plant in Plymouth, Mass., was ready to open after a two-and-one-half-year shutdown even though it did not have an approved emergency evacuation plan.

Agnes, who has been working with local and federal officials to create acceptable evacuation plans for the suburban towns surrounding the plant, was immediately approached by several NRC security guards.

When he continued to stand and address the commission, the guards grabbed him by both arms. As he yelled that he was tired of hearing "half-truths," Agnes was pulled from the row over several other spectators and dragged out of the hearing room.

He was not arrested, but was barred from the Rockville, Md., building.

"If that's the way they treat people, public safety officials, then that's a commentary on the fairness on this process," Agnes said in an interview after the hearing.

"I simply could not sit there any longer, after having worked on this project for two years with state and local officials, and hear the false-hoods, half-truths and misrepresentations that the NRC staff was making about emergency planning. It was absolutely disgraceful. My concern was that we were reaching a decision point and that the commissioners ought to know that at least one public safety official from the common-wealth took exception with what they said," Agnes said.

Dukakis and other state officials have urged the NRC to keep the 670-megawatt reactor shut down until an acceptable emergency evacuation plan is installed and tested. Last year, the Federal Emergency Management Agency said the previous plan was unacceptable.

But NRC officials, in their briefing to the commissioners, said the original management and equipment problems that triggered the shutdown on April 12, 1986, have been resolved. They added that evacuation planning, while not completed, is greatly improved and should not halt the reopening of the plant.

The commission declined to make an immediate ruling. NRC Chairman Lando W. Zech Jr. said the commission needed time to review testimony presented earlier in the day by Sen. Edward M. Kennedy and other state officials as well as the NRC staff's recommendations.

After the hearing, Zech told reporters that he did not know that the man removed from the hearing was a Dukakis adminstration official.

About an hour later, an NRC spokesman said the chairman had already drafted a letter expressing his regrets about the "unfortunate incident," explaining that he did not recognize Agnes.

"I hope you understand the need for us to exercise some control at our commission hearings so scheduled presentations can be made in an orderly manner," Zech wrote.

The commission usually does not hear public comment at such meetings. They made an exception for Kennedy, Lt. Gov. Evelyn Murphy and Rep. Gerry E. Studds, D-Mass., but refused to allow other state officials and local residents to speak.

Agnes acknowledged that he did not expect the commission to allow his testimony, but never expected to be physically removed.

"To impose a regime like they have here today, where people aren't even permited to stand and request permission to speak, I think is a very frightening spectacle," he added..

Earlier, Stephen Comley, an anti-nuclear activist, was removed by security guards when he held up a "Chernobyl" poster.