Iranian President Abol Hassan Bani-Sadr moved to consolidate power in his politically fractured nation yesterday, underscoring a growing feeling that the 13-week crisis over American hostages may be headed for a solution.

In Tehran, Bani-Sadr was appointed chairman of the ruling Revolutionary Council, apparently overcoming opposition by some council members to his plans for forming a government before a parliament is elected next month. The appointment must be approved by Iran's spiritual leader, Ayatollah Ruhollah Kohmeini.

Separately, the head of the council that runs Iran's national radio and television resigned in what some observers believe was a power play by Bani-Sadr, who has long complained that the broadcasting complex sought to discredit his election chances.

The resignation of Mohammed Mousavi Khoeni, who is the closest religious leader to the Islamic militants holding an estimated 50 hostages in the U.S. Embassy in Tehran, is also seen as part of Bani-Sadr's strategy to isolate the radical youths and end the crisis.

The landslide election 10 days ago of Bani-Sadr, an outspoken moderate on the hostage issue, is seen as a hopeful sign by U.S. officials who believe the new president's assumption of full powers in politically diffuse Iran is a potential key to settling the crisis.

Because its hopes about Bani-Sadr are based more on deduction and intuition than tangible developments, the Carter administration carefully has maintained a public posture of reiterating almost daily that it sees no sign of an imminent breakthrough.

Privately, however, administration officials are believed to feel that a confluence of a factors -- Bani-Sadr's election, growing Iranian concern about Soviet pressures and a new "package deal" proposal for cracking the impasse -- have created an atmosphere more conductive to a settlement than at any previous point.

In attempts to foster what they consider a favorable climate, officials in Washington have tried to provide Bani-Sadr maneuvering room that will enable him to move toward negotiations without exposing himself to charges of capitulating to American pressures.

Despite denials from the Carter administration, that has meant at least temporarily shelving U.S. plans to spell out regulations formally setting in place the economic sanctions the United States has threatened to impose unless the hostages are released.

As a practical matter, these sanctions have been in effect since shortly after the militants stormed the U.S. Embassy Nov 4. The United States subsequently froze Iranian assets in American banks and stopped trade and financial dealings between the two countries.

But the administration has decided that to codify the sanctions formally at this stage would give a new ammunition to forces within the divided Iranian power structure that would like to frustrate any attempts by Bani-Sadr to settle the dispute.

Even more important, the United States, in an effort to help Bani-Sadr find an escape hatch from demands for extradition of deposed shah Mohammad Reza Pahlavi, has backed off its original demand that any consideration of Iranian grievances must be preceded by release of the hostages.

Although the administration still says publicly that it will not yield on that point, it has given behind-the-scenes approval to a "package deal" worked out in cooperation with the United Nations Security Council and Secretary General Kurt Waldheim.

Under this proposed plan, an international commission would be appointed under U.N. auspices to go to Iran to inquire into the shah's alleged crimes against the Iranian people. At the same time, the hostages, although remaining in Iran, would be removed from control of the militants and be put in the custody of a neutral agency such as the International Red Cross.

Once the commission completes its investigation, it would return to New York to report to the Security Council. But the timing of when its findings are made public would be simultaneous with or immediately subsequent to the release of the hostages and their safe departure from Iran.

The commission would have no power to order or even call for the shah's return to Iran. Similarly, it would not be empowered to rule on whether Iran had violated international law by ignoring the immunity of American diplomats and using them as hostages to its demands.

These are the main elements of the plan that U.S. sources privately admit is the principal initiative being offered to the Iranians. According to the sources, the United States also is willing to consider "reasonable" Iranian proposals for changing various aspects of the plan.

But, the sources are careful to stress, the United States so far has received no clear signal of Iran's willingness to accept this plan as a basis for further talks. Instead, the responses from Bani-Sadr and key institutions in the Iranian power structure such as the Revolutionary Council have been contradictory and confusing.

The council, for example, has said publicily it welcomes the idea of an international commission, but its statement made no mention of surrendering the hostages to a neutral body like the Red Cross. Similarly, Bani-Sadr's public remarks have added up to a cryptic pastiche of vague optimism about a solution, coupled with repetitions of some of the original hardline Iranian demands about the shah and his wealth.

Most important, the sources noted, has been the continued U.S. inability to gauge the attitudes of Iran's most powerful figure, Khomeini, who has the power to overrule even Bani-Sadr's decisions.

Although Khomeini originally played a key role in egging the militants into storming the U.S. Embassy and taking the hostages, U.S. officials believe he now may be ready to withdraw his support from the captors. However, the Moslem religious leader has not said or done anything publicly to buttress that belief.

Addressing that point on Monday, State Departement spokesman Hodding Carter said it would be "pointless" for the United States to accept any agreement that lack Khomeini's approval. In Sum, he said, the administration still has not found "someone with the authority and the willingness" to negotiate meaningfully on Iran's behalf.

In private, though, U.S. officials remain hopeful that such a figure will emerge from the sorting out process now underway within Iran, and in their best-case scenario, they are banking on Bani-Sadr.

In effect, they hope he will prove sufficiently adroit to use the massive majority given him in the presidential election to face down his rivals within the government and the Revolutionary Council, including the die-hards who want to continue the confrontation over the hostages and those fundamentalist religious leaders who still resist any significant role for secular authority within Iran.

It is against that background that yesterday's events in Iran take on significance. First, by gaining approval from the Revolutionary Council to serve as its chairman, Bani-Sadr appears to have neutralized opposition to him on that important governing panel.

Then, Khoeni's resignation as head of the broadcasting complex's steering board is seen as a further dilution of influence for the embassy militants. Khoeni, who holds the religious rank below ayatollah, is their spiritual guide who leads Friday prayers at the embassy.

Although Khoeni said he was stepping down because of the bungled broadcast of Bani-Sadr's inauguration Monday night, his resignation is believed to climax a long power struggle between Bani-Sadr and officials who run the broadcasting system.

As spokesman for the embassy captors, Khoeni was the one who first suggested that the hostages would be subjected to spy trails -- a position consistently opposed by Bani-Sadr, who has urged a quick decision to release or punish the Americans.

Bani-Sadr has long complained that the broadcasting body unfairly discredited him when he was foreign minister for a brief period after the hostages were taken. While running for president, he said his candidacy was unduly ignored by the network.

That battle with media officials also framed Bani-Sandr's bitter feud with Sadegh Ghotbzadeh, who ran the national broadcasting complex until he replaced Bani-Sadr as foreign minister. Bani-Sadr blamed Ghotbzadeh for turning television and radio against him to clear the way for Ghotbzadeh's appointment.