Argentina's recent black-out drills in preparation for war with Chile over the Beagle Channel dispute were viewed by much of the world with more amusement than alarm.

Nobody would have been laughing, however, if Argentina had nuclear weapons.

The possibility of developing countries, which have fought dozens of regional wars since World War II, acquiring and using atomic bombs is the single greatest worry of many arms control experts today.

Would the Pakistani military government have allowed India to wrest half of Pakistan from its control if it had possessed nuclear weapons in 1971?

Would the Greek junta have watched helplessly while the Turkish army invaded Cyprus if it had a nuclear capability in 1974?

Would Libya or Iraq bring a nuclear holocaust to the Middle East if they succeed in current efforts to obtain atomic weapons?

How would China, which already has hydrogen weapons, respond if Taiwan appeared to be developing an independent nuclear capability?

'I think there are significant risks of nuclear weapons being used in regional wars in the future," said Deputy Under Secretary of State Joseph S. Nye. "But I think if you manage the process correctly, we can keep that probability a low one rather than a high one."

The question is how?

Some experts stress the importance of continuing to press holdouts to become parties to the Nuclear Nonproliferation Treaty, which has now been signed by 116 countries.

Nations that sign the NPT agree not to "acquire" or seek aid in developing nuclear weapons in return for assistance with their peaceful atomic power programs.

"The NPT is the best guarantee against nuclear proliferation," declared Sigvard Eklund, director-general of the International Atomic Energy Agency. "I attach great significance to the political decisions of these countries not to go ahead with nuclear weapons."

But despite the best efforts of the Carter adminstration, half a dozen countries with sophisticated nuclear research programs adamantly refuse -- for a variety of reasons -- to sign the treaty.

In addition to India, which has already demonstrated its atomicweapons potential, non-NPT states include Israel, South Africa, Pakistan, Brazil and Argentina.

Beyond that, what does one make of countries like Iraq and Libya, which have signed the NPT but say they want to acquire nuclear weapons anyway?

Jeremy J. Stone, director of the Federation of American Scientists, suggests that the Libyan case raises the question whether some countries are "false adherents" to the treaty -- signing the NPT with fingers crossed in order to gain access to nuclear materials and technology.

In theory, any NPT signatory that secretly has a weapons program in mind should ultimately be caught, since countries that sign the treaty agree to put their nuclear facilities under IAEA "safeguards."

The IAEA attempts under these safeguard arrangements to keep track of all nuclear material provided to a country for use in its research reactors or power stations, and to ensure that none of it is diverted for possible fabrication of weapons.

While the IAEA has recently improved its safeguard efforts, agency officials concede that "more men and more money" are needed if the world is to be confident that any violation would be quickly detected.

Interestingly, some of the countries that are mentioned as potential proliferation concerns, such as South Korea, favor strengthening the safeguard system.

"I think if they strengthened the IAEA's safeguards program," said Korean Atomic Energy Commissioner Byoung Whie Lee, "you could manage the problem of proliferation without any difficulty."

One reason countries like South Korea take this position is they would prefer it to the Carter administration's current policy of denying them "sensitive" nuclear technologies like plutonium reprocessing.

South Korea, Brazil and Argentina remain convinced -- despite intensive American efforts to persuade them otherwise -- that reprocessing will be important for their atomic power programs by the 1990s.

The wisdom of the U.S. effort to block the spread of reprocessing plants, however, was confirmed by deposed Pakistani President Zulfiqar Ali Bhutto's recent confession that his motivation in trying to purchase a plutonium plant from France was to provide Pakistan with a nuclear weapons capability (see box).

France and West Germany now have both largely come around to the Carter administration's view that selling reprocessing plants to developing countries is a mistake. Both have announced a moratorium on future sales, although West Germany intends to honor an agreement to provide Brazil with a laboratory-scale reprocessing facility.

It is hard to argue, though, that a nation like South Korea -- which has signed the NPF and intends to have 43 atomic power stations in operation by the year 2000 -- can reasonably be expected to rely entirely on the United States, or any other country, for its nuclear fuel supply.

"Our aim," a French official said, "should be to set up some kind of international system or institution under which services of reprocessing or uranium enrichment could be guaranteed to certain countries, with out any great risk of proliferation."

Many experts feel an excellent place to launch this kind of initiative would be in Asia, where a regional reprocessing and waste disposal center might serve the atomic power stations of Korea, Taiwan and the Philippines.

"One would hope the question of reprocessing for Korea and Taiwan would be solved this way," Eklund said.

On the bright side, one of the more hopeful auguries for nonproliferation is the present unanimity of supplier nations on the need to prevent additional countries from acquiring atomic weapons. This concensus includes the Soviet Union, which thus far has an unblemished nonproliferation record.

"There is among the major weapons states a degree of consensus on nuclear nonproliferation that is 100 percent," a French official said.

There is less agreement on the outlook for keeping the number of nuclear weapon states frozen. The big worry of many arms control experts moreover, is that the next country that explodes an atomic bomb may trigger a rush to join the club.

"You'll either have no further proliferation -- or a lot," a French Foreign Ministry official suggested.

"I fear that if some country beyond those that have the bomb now felt it required it, that it would force an overall reassessment of the uneasy present situation in the world," a senior West German official added.

Nye, the Carter administration's top nonproliferation adviser the past two years, says he is hopeful this kind of destabilizing situation will not come to pass.

"I think the question is whether you can gain control of this, or whether you are like a man on a bicycle riding full speed down the hill discovering he has no brakes," Nye said.

"What we've seen is there is a breaking system, we can oil it, improve it, and that gives me a sense of optimism about our ability to control things rather than having events in the saddle," he added.

So is Nye more optimistic today than he was two years ago about the prospects of preventing the spread of atomic weapons?

"I guess," he replied, "that I'm more optimistic -- marginally."