Iraq has blocked inspection of its nuclear installations in a move that raises uncertainties about international safeguards over weapons-grade nuclear fuels in a war zone as well as about the fate of two French-built reactors near Baghdad.

A spokesman for the International Atomic Energy Agency, which inspects nuclear installations to guarantee against illegal diversion of materials for military purposes, said it was informed by Iraq that its inspectors cannot come to Baghdad to check the two reactors during current war conditions.

Iraq is a signatory of the Nuclear Nonproliferation Treaty and had also concluded a special safeguards treaty with the Vienna-based agency that normally would make such inspections mandatory. Neither agreement covers war situations, however.

There were reports that the Iraqi reactors may have been damaged by Iranian air strikes during the first week of their current war.

A spokesman for the International Atomic Energy Agency said Iraq told the agency that it "would be informed as soon as safeguards inspections can be resumed."

After getting authorization to discuss the matter, the spokesman said, "We will be insisting again and again" on the resumption of inspections.

French officials are indicating extreme embarrassment at the uncertainty surrounding the reactors, known as Osirac and Isis, in a war situation.They say that it places the whole problem of nuclear proliferation in a new light and that the problem should be carefully examined by the international community.

"We are in a completely new situation that was not foresseen in any international treaties," said a knowledgeable French source. "The problem is raised for international reflection just as sharply as it was in 1974 when India made its explosion."

Thought must now be given, he said, to finding safeguards against diversion of materials from nuclear facilities in war zones.

The IAEA said that in response to its request, Iraq has given its assurance of, in the spokesman's words, "the integrity of all materials subject to safeguards."

A French press report based on interviews with French nuclear technicians repatriated from the Iraqi nuclear center near Baghdad said that the 26 pounds of highly enriched, weapons-grade uranium fuel that were powering the research reactor Isis, the smaller of the two reactors, have been removed and that the irradiated material is being stored in water in an underground canal. It is normally used to transfer uranium bars between the two reactors.

The larger power reactor was not yet in operation, and it is thought that there was not yet any fuel delivered for it, although the fuel in Isis could be transferred to the power reactor. The first French uranium delivery for Isis is said to have taken place in June.

Vienna agency inspectors normally are on hand when nuclear fuel is loaded into a reactor. They install closed circuit television cameras with seals that are considered to be tamper-proof around the reactor core, and they visit the reactor on a regular schedule to check the seals and the film tapes.

The French noted that once uranium fuel is irradiated for use in a reactor, it cannot be used for weapons production without going through highly complicated reprocessing that the Iraqis are not equipped to perform. While the uranium fuel belongs to Iraq, the French have made it known privately on a number of occasions that if the Iraqis ever tried to keep spent uranium fuel instead of returning it to France for reprocessing, further supply would be immediately cut off.

After the rocket-bombing of the center on Sept. 30, most of the French technicians were hurriedly repatriated to France. About a dozen French volunteers stayed behind.

While the French Atomic Energy Commission will not make any official comments about conditions at the Iraqi atomic center, informed French sources say that the technicians who stayed behind are no longer necessarily on duty there at all times since the site has become a target in the war.

"The French are not watching over the center," said one source. He added, however, that they do have access to the sheltered uranium fuel and checked on it as recently at three days ago.

If it were still usuable the uranium would only be enough for one bomb. But the Iraqis have bought from Italy a device, known as a "hot cell," which permits technicians to learn how to extract the plutonium needed to make a bomb even from irradiated uranium. The United States protested to Italy the sale of that piece of equipment. It is not large enough to extract enough plutonium to matter in a reasonable period, but experts say a well-grounded scientist could learn how to do it on larger scale by practicing with the device.

Sophisticated Israelis admit that the French reactor program in Iraq does not represent a real and immediate proliferation danger. The real danger, they say, is the wide distribution of nuclear know-how that is a major feature of the multibillion-dollar French program in Iraq.

The French have created a "nuclear university" at the center that can train 600 scientists at once. The Iraqis have indicated that they would allow scientists from other Arab and Islamic countries to be trained there.

It was speculated that the Sept. 30 raid on the center involved disguised Israeli planes rather than Iranians because the idea of an "Islamic bomb" has taken on near-sacred overtones in the Moslem world. Iranian President Abol Hassan Bani-Sadr subsequently admitted that the attackers were Iranian, but he said the bombardment was meant for anothher target nearby.

In April 1979, major components for the reactors were blown up in southern France in an obvious effort to slow down the Iraqi program. With more apparent reason than in the case of the bombing, that explosion also was attributed to the Israelis.

The raid on the Iraqi center scored no direct hits on the reactor buildings, but French technicians evacuated from Iraq estimated that the damage to related installations would take a year to repair.