The Soviet Union might have developed the first nuclear chain reaction and possibly the first atomic bomb if its Academy of Science had approved a proposal presented to it in August 1940, according to a paper presented this week at the Smithsonian Instittution's Wilson Center.

Historian David Holloway, in his study of "The Soviet Decision to Build the Atomic Bomb," said the leading Russian nuclear physicist, Igor Kurchatov, argued in mid-1940 for additional funds to develop nuclear fission, stressing its "military significance" and the prospect that "a uranium bomb could be built."

It was not until December 1941 that the U.S. government began its first serious coordinated work on Developing a nuclear bomb.

When the Soviets finally did mobiize their major atom bomb-building effort in 1945 - after the U.S. attack on Hiroshima - the most experienced Russian industrial managers were given the task and best scientists and workers were ordered into the effort, according to Holloway.

Their successful first atomic bomb test four years later, showed the speed with which a full-scale Soviet technical effort can achieve its goal - a result most recently reaffirmed in the Russian development of new intercontinental ballistic missiles.

"Had the Russians not held up [in 1940] I am absolutely convinced they would have gotten a chain reaction the same time as we did, if not before," was the comment yesterday of Arnold Kramish, a nuclear historian who worked on the U.S. Manhattan Project that built the first bomb.

But the Soviet Academy in 1940, according to Holloway, turned the Kurchatov 1940 proposal down because its prospects for success seemed so far in the future. The June, 1941 German invasion of Russia then halted all Soviet nuclear fission research and Kurchatov turned his attention to work on navy ships.

One of his younger assistants, G.N. Flyorov, however, kept pressing for 1942, he wrote to Premier Josef Stalin "explaining the nature of the uranium problem in both its military and its peaceful aspects," Holloway says.

The 28-year-old Flyorov had found that American and British scientists, who regularly had been writing on nuclear developments before mid-1940, had stopped publishing. This, he pointed out in his letter to Stalin, meant "that nuclear research in the United States had now been made secret," according to Holloway.

In fact, the scientists outside Germany all had informally agreed to stop writing for fear their papers could help Hitler develop an atomic bomb.

Stalin had the Flyorov letter reviewed. It was linked with other intelligence information about German and American atomic activities, some fo which apparently came from the British spy, scientist Klaus Fuchs, according to Holloway. In the summer of 1942, Fuchs was working on the British program; he did not come to the United States until December, 1943.

The fact that other countries were moving ahead gave impetus, Holloway believes, to the Soviet State Defense Committee decree in December, 1942 that a nuclear research laboratory be started with Kurchatov as its head.

This was not a full-scale commitment since the country at the time was fighting for its survival with the Germans at the gates of Stalingrad and with Leningrad under siege. In fact, it was not until the end of 1944 when the tide of the war had turned that Kurchatov had 100 researchers at work in his facility.

At that point, the Soviets decided to try to get some outside help for their project.

"As the Red Army moved into Germany, strenuous efforts were made to recruit German scientists to work for the Soviet Union," Holloway reports. There was even a list of scientists most desired.

One, Baron Manfred Von Ardenne, agreed to go to Russia "for two weeks of talks," Holloway writes and the "two weeks became 10 years." The day he left Berlin, according to Holloway, "Red Army soldiers began to dismantle his laboratory for shipment to the Soviet Union." Even his staff went with him.

The victory over Hitler allowed the Soviet nuclear effort to proceed unhindered.

The first U.S. nuclear test shot at Alamagordo, N.M., occurred July 16, 1945. At that time, then-President Harry Truman was meeting at Potsdam with British Prime Minister Winston Churchill and Soviet leader Stalin.

Holloway, after studying both American and Soviet documents, still cannot determine whether Stalin knew Truman was talking about the atomic bomb when he told the Soviet leader after one meeting that "we had a new weapon of unusual destructive power."

The Soviet defense minister at the meeting, Marshal Georgi K. Zhukov, wrote in his memoirs that Stalin remarked after the meeting that "we'll have to have a talk with Kurchatov today about speeding up our work."

Another Soviet memoir from a Potsdam participant, however, records the Turman statement but adds that "Stalin . . . . did not get from the conversation with Truman the impression that what was mentioned was a weapon that was new in principle."

In any event, the Soviet program was not speeded up until August, 1945 after the two U.S. atomic bombs were dropped on Japan.

Thereafter, according to Holloway, Stalin decided "to launch an all-out effort to develop the atomic bomb."

He quotes from an unpublished biography of the then-head of Soviet munitions who had been called to the Kremlin in mid-August, 1945 to meet Stalin:

Kurchatov joined the session and Stalin reportedly said, "A single demand of you, comrades: provide us with atomic weapons in the shortest possible time. You know that Hiroshima has shaken the whole world. The equilibrium has been destroyed. Provide the bomb - it will remove a great danger from us."

Four years later, the Soviet exploded their first atomic device.

"That came at the right time technically speaking," historian Kramish said yesterday in correlating the Russians' progress to the time it took U.S. scientists from their development of a chain reactor.

Kramish added that if U.S. officials and scientists had known, at the time of the Manhattan Project, of the Soviet 1940 nuclear accomplishments, "we would have been very frigtened."

The fact is, Kramish said, "we knew essentially nothing" about the Soviet program. He said only a minority of the Americans thought it would take the Russians only four years to catch up once existence of the American U.S. atomic bomb became public.

Gen. Leslie Groves, head of the American effort to build the bomb, thought it would take them 15 to 17 years, Kramish said.

Both he and Holloway agreed that Soviet spies had helped push the Soviet program ahead but by reporting what U.S. scientists were doing rather than by providing secret plans.

For example, Kramish and Holloway recalled that in 1947 and 1948, the Soviets received word that the United States was considering the "super" or hydrogen bomb.

Within a short time, the Soviets in 1948 had established their special team of scientists to work on the H-bomb program. Holloway said he believes that such information "may have come from Fuchs."

A fellow at the Wilson Center for the past year, Holloway is a lecturer in politics at the University of Edinburgh. For the past four years, he has specialized in analyzing the Soviet weapons-building system and is writing a book on the Russian atomic program. Only one English-language book, produced by Kramish 20 years ago, has attempted to describe the soviet nuclear weapons program. CAPTION: Picture 1, This tent, located outside Moscow, is where the Russians built their first nuclear reactor in the mid-1940s, leading to atomic bomb development. Atomizdat - Moscow; Picture 2, IGOR KURCHATOV . . . pressed to built Soviet A-bomb; Picture 3, KLAUS FUCHS . . . apparent information pipeline