The apparently successful Israeli raid on Iraq's nuclear installations just a week ago came as a sharp reminder that about 15 new countries could quickly break into the five-nation nuclear club.

"Any industrialized country with a nuclear power program can make the bomb relatively rapidly if it chooses to do so," a French atomic official said.

Over the years, France and the United States have accused each other of being the most guilty fo nuclear proliferation, but they have been coopeating closely for more than five years in the desperate, and probably doomed, attempt to keep the door of the nuclear club shut.

The other three members of the inner circle -- Britain, the Soviet Union and China -- have much cleaner records in avoiding the spread of nuclear weapons, particularly the two Communist powers.

Although India has exploded a nuclear device, experts believe it has not done much to develop a military nuclear capability.

The Soviets may be changing their thinking about non-proliferation. Until recently, the only country to which the Soviets had agreed to provide nuclear technology outside their own highly controlled bloc was neighboring Finland. But the Soviet agreement to build a research reactor for Libya, whose unpredictable ruler Muammar Qaddafi openly proclaims his advocacy of an "Islamic bomb," may mark a new departure.

The French were instrumental in the two nuclear weapons programs that the experts say are the most advanced -- in Israel and South Africa. Thanks to their French-provided reactors, both countries already have the bomb but have never actually exploded it, according to the weight of expert opinion here and elsewhere.

However, soon after India exploded a nuclear device in late 1974, with atomic materials gathered from a poorly policed Canadian heavy-water reactor, France took fright along with the other members of the nuclear club about where the unsafeguarded sale of nuclear technology was leading.

Then-U.S. president Gerald Ford and French president Valery Giscard d'Estaing agreed that the main sellers of technology should agree to sell with extreme prudence any equipment that could be used to short-circuit the elaborate, but not foolproof, international inspection procedures of the 12-year-old, Vienna-based International Atomic Energy Agency.

Virtually everyone with nuclear material to sell or with known nuclear ambitions joined the meetings of the London group that was born of the Ford-Giscard concern that nonproliferation should not fall victim to the intense commercial competition for lucrative nuclear contracts. The London group identified three sensitive areas where caution should be exercised -- uranium enrichment, chemical reprocessing and heavy water.

The French stressed that nothing in any of those three fields was involved in their agreement in late 1975 to ensure French oil supplies from Iraq by providing it with a "nuclear university" centered on two reactors of the type France already had outside Paris at Saclay.

Questions were raised in France about what real need oil-rich Iraq had for an advanced nuclear program. But the oil Iraq had for sale and the money it earned from the oil were effective silencers. Besides, French officials argued, Iraq had signed the Nuclear Nonproliferation Treaty and agreed to all the safeguards and inspections of the 110-nation Vienna agency.

Who were the Americans to complain, the French asked, about the spread of nuclear know-how at the training center for Arab world scientists outside Baghdad? It was then-president Dwight Eisenhower's well-intentioned Atoms for Peace program that had started the process of "intellectual proliferation" in the 1950s, and most of the world's 77 research reactors in countries outside the nuclear club were sold or given by the United States.

The leading Chinese nuclear physicists were all trained in the United States.

With the fervor of the newly converted, French experts began pressing the alarm bell about Pakistan. With a technique that had not been singled out by the London group as a danger, the centrifuge system, Pakistan was determined to make atomic arms to protect itself against the presumed Indian nuclear threat, the French asserted.

U.S. intelligence is understood to be satisfied about the accuracy of the French report that Pakistan was secretly putting together a nuclear centrifuge. The parts allegedly were ordered from 14 countries following plans stolen by a Pakistani physicist, Abel Kader Khan, who had been employed in the Netherlands by the Anglo-Dutch-West German consortium building the first centrifuge. Journalists who tried to interview him in Pakistan were beaten, as were the French ambassador and a colleague when they tried to approach the Pakistani nuclear installations.

For all their complaints about other people's laxity toward Pakistan, the French had tolerated a major contribution to the Pakistani program by allowing Niger, a French client state with major uranium deposits, to sell 150 tons of uranium ore to Pakistan and 300 tons to Libya, a heavy financial backer of the Pakistani nuclear program that had no immediate use program that had no immediate use of its own for the unprocessed uranium. The ore was mined for Niger by a company under the control of the French Atomic Energy Commission.

Niger's sales were legal and were placed uner Vienna agency inspection, but the bookkeeping for Niger's share of production, as reconstructed in Paris for reporters by the French AEC's top brass, clearly showed that illegal diversion of significant unaccounted amounts was possible.

For those most concerned about proliferation, France and the United States are not currently considered the main culprits. Several near-nuclear countries that are considered to have weapons capacity but no ambitions of their own are regarded as being sloppy about how closely they police their profitable equipment sales.

Canada was for many years considered to be the principal offender in that category with sales of Candu heavy-water reactors that are the fastest ticket to rapid production of enough plutonium to make bombs. Canada is currently negotiating Candu sales to Mexico and Romania. But the Canadians have since tightened up their procedures and have been replaced by the West Germans, Italians and Swiss as the problem suppliers, experts say.

Italy supplied to Iraq the small "hot cell" that could have been used to study how to extract plutonium for bombs from uranium.

West Germany sold a heavy water reactor to Argentina, which has not signed the nonproliferation treaty. The West Germans have also sold a huge nuclear project to Brazil, which also has not signed the treaty.

The Brazilians turned around and made a deal with Iraq to swap nuclear technology for the Iraqi oil they desperately needed. It amounted to a three-cornered trade in which Iraq was to get forms of nuclear aid from West Germany that the French had carefully denied Baghdad.

Canada, Italy, Japan, West Germany, Sweden, Switzerland, Belgium, the Netherlands and Spain are considered to be the main countries that have the capacity but not the ambition to become nuclear weapons powers.

India is a question mark to the experts. Even though it has exploded a nuclear device, some experts express doubts that it did much with the knowledge it acquired. Its rival Pakistan is clearly going for the bomb.

Argentina, Brazil and, to a lesser extent, Chile are considered countries to watch. South Korea, with U.S., Canadian and French equipment on hand or on order, is considered another potential problem.

Much further down the road are countries in regions marked by dangerous national rivalries. France has nuclear "framework" agreements with all three countries of former French North Africa -- Algeria, Morocco and Tunisia -- that could spell trouble, depending on what winds up filling in the frames. France and West Germany have also signed nuclear power plant agreements with Egypt.

Despite all of Israel's suspicions, Iraq had always argued officially that it was only interested in peaceful technology. Doubt was cast on that by Iraq's refusal to accept the French offer to replace deliveries of weaponsgrade 93 percent enriched uranium to power its reactors with "caramel" fuel, 6 to 8 percent enriched with a chemical bonding process that makes it impossible to extract plutonium from the spent fuel with any known technology.

It is widely assumed in Paris that if Iraq should ask for French help in rebuilding the destroyed reactor, the French government would argue that the old contract no longer applies and insist on use of nonsensitive fuel.

But that is not the only concern. There are those, including a number of French scientists, who believe that a "blanket" of nonenriched uranium can be placed around the core of the reactor to serve as a breeding ground for enough plutonium to make one atomic bomb a year. While they cast doubt on the possibility of doing that without being detected, officials at the Vienna agency conceded that this is technically feasible.

Another difficulty is that the Nonproliferation Treaty may be renounced by any signatory on 90 days' notice. That would presumably give others time to anticipate a violation, but that loophold serves to underline the voluntary nature of controls.

After the war broke out between Iran and Iraq, the Iraqi government told the Vienna inspectors that they could not received, and no inspections were made from September until the last one took place in January.

Another one had been scheduled to take place for the day following the Israeli raid. The Iraqi government has asked the agency to postpone it until the end of June, but the authorities in Vienna has asked to go sooner.

"We are not a police agency," said IAEA spokesman Georges Delcoigne. "We are an accounting system. We work with the authorities."