Soviet request for help with nuclear disaster out of character. Crisis came on heels of new Gorbachev offer on arms reduction

In a curious way the recent Soviet nuclear disaster at Chernobyl was a plus for the Soviet Union. It showed the Soviets to be fallible, and human about it. They admitted the disaster (although very tardily) and asked for help from two neighbors, Sweden and West Germany. Although the Soviet response fell far short of what the West would regard as openness, the Soviet Union behaved in a way that would have been unthinkable for them in the past.

The occasion to admit fallibility and ask for outside help fits, to some extent, the posture of modern reasonableness which has been the trademark of Soviet diplomacy ever since Mikhail Gorbachev became the head man in Moscow.

Only a day before news of the nuclear disaster broke, Soviet diplomacy proposed, or appeared to propose, ``bold'' reductions in conventional weapons in Europe. There are few things the Soviet Union might do which could be more welcome to Western Europeans than a reduction in the number of soldiers and warplanes kept in the heart of Europe by the Kremlin.

The prime purpose of Western diplomacy for a generation after the Napoleonic wars was to get Russian troops out of Central Europe. It took a long time.

The Russian revolution in 1917 spared the West Europeans a similar problem after World War I. But Soviet victory in 1945 revived for the West Europeans of today the old and familiar problem.

Soviet troops are still deep in Central Europe. The imperial barracks at Potsdam once housed the regiments of the Prussian guards. Today those barracks house Soviet soldiers. Potsdam, now a part of East Germany, is a Soviet military camp. Russian is the language most heard in the shops of Potsdam. Soviet soldiers and their dependents are to be seen and heard all over East Germany, and in Czechoslovakia and Hungary.

Today Soviet military power again dominates Central Europe as it did after the downfall of Napoleon. For Moscow to even hint at the possibility of reducing the numbers of those Soviet soldiers, tanks, and warplanes in and around Potsdam is to send a welcome ray of hope over Western Europe.

In the battle of propaganda, the move was neatly timed and executed to take advantage of the wave of disapproval which swept over Western Europe in the wake of the American air strike at Libya. Once again, Ronald Reagan projected the image of a reckless gunslinger out of some Hollywood horse opera while the Soviets talked of arms reduction.

President Reagan was meanwhile on his way to the Tokyo summit of the industrial democracies -- Britain, France, Italy, West Germany, Canada, the United States, and Japan. He was taking with him to that meeting one thing of primary value to the other attendees -- his decision to keep arms control alive for yet another round.

The fabric of arms control would have been torn earlier this month when the issue at the White House was whether to break through the old limits set in the second Strategic Arms Limitation Treaty (SALT II) on numbers of missile launchers. The new USS Nevada carries 24 launchers. If she were to be commissioned without scrapping older nuclear submarines, the US would be over the old treaty limits -- which have been continued by mutual consent beyond the expiration date of the unratified SALT II treaty.

As it is, two of the old Poseidon submarines are to be sent to the ship breakers for scrap metal. The old set of limits survives. Therefore, the way is still open to the possibility of some new agreement emerging out of further Reagan-Gorbachev summits.

Probably the most likely area of a new agreement would be in intermediate-range weapons of the kind which both sides have recently been deploying in Europe -- the Soviets' SS-20 model, and the US's cruise and Pershing II missiles. Much of the preliminary work has been done in this area.

If the two principals -- Reagan and Gorbachev -- truly wanted to reach an agreement reducing the number of such weapons in Europe they could undoubtedly do so. It could be the crowning event of another Reagan-Gorbachev summit.

Will there be another summit?

Probably yes, now that Reagan has signaled his interest in continued arms control by the decision to continue to observe the old limits. Without that decision, to be confirmed at Tokyo, the second Reagan-Gorbachev meeting would probably never have taken place.

Now, barring some new horror in East-West relations, it seems likely that the second meeting of the ``big two'' will occur after American election day, with the third meeting to follow in 1987.

There is an outside possibility that the third in the series could even bring a SALT III agreement under some other name. Dominant thinking inside the Reagan White House is one of deepest suspicion of any new arms control agreements with the Soviets. The most that can be said for the possibility is that Mr. Reagan is still leaving the door open. He has resisted the urgings of his hawkish right wing to slam the door.

Thus, it is still worthwhile for the friendly allies during the meeting in Tokyo, and later, to continue to urge Reagan toward the idea of doing more arms control business with Moscow. They just might be able to tip the scales at the White House in favor of this goal.

Therefore, it is conceivable that Reagan-Gorbachev meeting No. 2 could produce an agreement to reduce intermediate-range missiles in Europe and Reagan-Gorbachev meeting No. 3 could produce a new agreement on strategic weapons.

But here we are talking about outside possibilities rather than likelihoods.