The presidential commission investigating the nuclear accident at Three Mile Island dissolved its citizens advisory group yesterday before meeting with the group to solicit its advice.

To hear the commission tell it, the advisory group was disbanded because it wanted a far more active role in commission activities than the commission had promised it. The advisory group said it was broken up because it asked the commission for information it had been informally promised, then formally denied.

Whatever the reasons, "this is the shortest-tern advisory task force I've ever sat on," said Rich Pollack of Critical Mass, one of nine members of the advisory group. "The situation is ludicrous."

The panel, called the Kemeny Commission after its chairman. Dartmouth College President John G. Kemeny, was appointed by President Carter in mid-April to find out what caused the accident at Three Mile Island and make recommendations to prevent a recurrence.

In response to public interest groups, the commission agree four weeks ago to appoint a group of nine "citizens" to advise it during its six months of investigation. The citizen advisory group said yesterday it had been promised access to commission records, consultants and staff. The commission denied making any such promises.

"The role this group envisioned for itself was vastly different from the role we asked them to play," said Barbara Jorgensen, chief of information for the Kemeny Commission. "They wanted to be inside and we wanted them to play an advisory role and answer nine questions addressed to the broad issues of nuclear power."

When the advisory group showed up at the commission's office yesterday morning, Jorgensen said, it presented a list of what she called "11 demands" of the commission. The demands included copies of all staff memos, draft reports and work plans, access to all federal and industry documents subpoenaed by the commission and depositions taken by the legal staff.

In addition, Jorgensen said, the advisory group asked for the opportunity to critique and review the commission's recommendations before they went to the White House and to review the list of witnesses and recommend additional witnesses.

"We told them that was unacceptable and they asked us to get in touch with Dr. Kemeny and ask him if it was unacceptable," Jorgensen said. "We tracked Dr. Kemeny down late in the afternoon and he immediately said that was not the role he had envisoned. We went back and told them what he said and that was the end of it.

"We didn't dissoolve them. They dissolved themselves because they refrsed to take on the role we had envisoned for them. The commission feels that the active participation by an outside group in the workings of the investigation is inappropriate to the commission's commitment to a completely independent and objective investigation."

The advisory group tells the story somewhat differently. While insisting it needed access to documents "that industry and the federal government already had," members of the group said they asked for little more than health records and the whole-body radiation counts of people living near Three Mile Island.

"We'd agreed to keep everything confidential," said Ellen Weiss of the Union of Concerned Scientists, another of the advisory group's members. "We thought that would be enought but we heard differently yesterday morning. We were told we'd be treated differently yesterday morning. We were told we'd be treated no differently than any other member of the public." CAPTION: Picture, A short-lived citizens advisory group formed to counsel the presidential commission investigating the Three Mile Island accident gathers for the first and last time. From left to right, William Millerd, Rich Pollack, Katherine Chamberlin, Mark Widoff, Jim Harding, June Allen, Rosalie Bertell and Ellen Weiss. By Margaret Thomas - The Washington Post