AMONG THE MOST telling indicators of the magnitude of the Chernobyl reactor disaster have been the Soviets' hesitant inquiries in the West about possible advice and assistance. First there were the requests to West Germany and Sweden for suggestions on controlling the graphite fire. Then there was a question whether the Swedes, with their specialized facilities, could take patients suffering from exposure to radiation. Proud of their technical capacities and secretive to the point of obsession, the Soviets make these kinds of requests only under the pressure of the greatest emergencies. Taken together with the readings of airborne radioactivity in neighboring countries, these signals of distress provide a far more accurate sense of the event than the Soviets' tight-lipped and unhelpful formal statements.

The Soviets' continuing refusal to provide reliable information regarding the accident is contributing to the anxiety and anger rising in, particularly, Western Europe. So far there is no proof that the accident has endangered human health outside the Soviet Union. But with the fire still burning out of control and with no reports on what might actually be happening at the site, it's difficult to know exactly what may happen over the coming days. A good deal depends on which way the wind blows.

Unquestionably there must be vast confusion at Chernobyl, and there must be much that Soviet officials themselves are frantically trying to ascertain. Seven years ago at Three Mile Island, enormous confusion continued for some days in an atmosphere that was as open as that at Chernobyl is otherwise. It's a good guess that uncertainty contributes to the Soviets' reticence. But their claim of such a relatively small death toll in this catastrophe seems highly implausible. The impression here is one of much wider loss of life and much greater suffering.

The precedent of Three Mile Island is worth following. In the aftermath of that accident, our federal government instituted several inquiries that examined the accident in great detail and published their findings for the world to consider. Those reports provided valuable guidance in reactor design and improvement in safety standards, for builders not only in the United States but throughout the world -- including the Soviet Union. The Soviets have a responsibility to do the same thing. The International Atomic Energy Agency, of which they are a member, is well equipped -- if the Soviets were to allow it -- to provide conduits in both directions, of foreign advice for Chernobyl and reporting from there to the rest of the world.

Other countries, including this one, have a moral obligation to provide any help that might be useful. But the Soviets have a reciprocal obligation, whether they choose to acknowledge it or not, to offer accurate information on a great catastrophe the consequences of which will hardly be confined to the Soviet Union.