UPDATE : Spy Charges Aimed at A-Bomb Pioneers Draw Counterattack : Eminent scientists rise to the defense of J. Robert Oppenheimer, other physicists charged in book with leaking secrets to the Soviets in the ‘40s.

Did J. Robert Oppenheimer, Niels Bohr and other renowned Western physicists who helped develop atomic weapons in the 1940s knowingly leak some of their secrets to the former Soviet Union?

An explosive revelation if it were true. A dynamite book. And a bombshell of a story.

Now, just such an allegation has burst on the scene, and it has produced enough literary fallout to worry its authors and publisher alike.

A string of eminent scientists who were involved in America’s first nuclear weapons program has attacked the charges as erroneous, pointing out errors of fact in the story that they contend cast serious doubt on the credibility of the basic allegations.

Editorial writers have denounced the allegations as inaccurate. And--worse yet from the publisher’s point of view--sales of the book in which they appear have been hurt.

The charges are contained in “Special Tasks,” the memoirs of Pavel Sudoplatov, a former Soviet spymaster who oversaw many of Moscow’s secret intelligence operations--including those seeking information about the atomic bomb.

In Chapter 7, titled “Atomic Spies,” Sudoplatov alleges that Oppenheimer helped leak atomic secrets to the Soviets and arranged for Klaus Fuchs, a British scientist later convicted of spying, to work at Los Alamos National Laboratory in New Mexico, where the bomb was built.

He also asserts that Bohr, the respected Danish physicist who did pioneering work on nuclear weapons for the West, met with a Soviet scientist in Holland and helped him correct a problem in Moscow’s design for a nuclear reactor that helped Russia develop a bomb more quickly.

And he contends that besides Oppenheimer, other famous scientists who came here to work on the project, including Enrico Fermi of Italy, Leo Szilard of Hungary and George Gamow of Russia, allowed Soviet moles to copy documents and “were knowingly part of the scheme.”

On the face of it, Sudoplatov seemingly ought to know. A general in the Soviet KGB--and its director of atomic intelligence during the World War II years--he was in charge of the Soviet Union’s efforts to get hold of the plans.

The authors also lend the book apparent credibility. It is co-authored by former Time magazine Moscow correspondent Jerrold L. Schecter--who was instrumental in the publication of the memoirs of the late Soviet premier Nikita S. Khrushchev--and his wife, Leona P. Schecter.

But the volume has set off a chain reaction of criticism that would be enough to give pause to any reader:

Physicist Hans A. Bethe, who was head of the theoretical division at Los Alamos in the 1940s; Richard Rhodes, author of “The Making of the Atomic Bomb”; and Roald Sagdeev, former director of the Soviet Institute of Space Research, all have contradicted key details.

And the American Physical Society, a 43,000-member organization of physicists based in College Park, Md., has held a press conference in which five nuclear experts denounced the charges as inaccurate and probably fictitious.

Moreover, critics who have pored over the volume say Sudoplatov, now 87, provides little real evidence to support his assertions. Indeed, except for a stray phrase or two, he does not suggest that they committed treason. He portrays them more as naive or undisciplined.

In seeking to debunk Sudoplatov’s specific allegations, critics say:

* Oppenheimer could not have hired Fuchs. The British scientist went to Los Alamos as part of a scientific investigative team appointed by the British government, and Oppenheimer could not have had any influence over who was picked. All team members had full access to the plans.

* Bohr did meet with a Soviet scientist, but faithfully reported the session to Western authorities, and did not reveal any secrets. Moreover, the first Soviet reactor was not built until a year after that session--well beyond what should have been the case if Bohr had leaked.

* Oppenheimer, Bohr and Szilard all shared a conviction that the United States should tell the Soviets about the bomb project before using the weapon and should begin discussing international control of the device. But they were not for giving Moscow any technology.

Other major details are just plain wrong. Examples: Szilard never worked at Los Alamos, despite Sudoplatov’s claims. Denmark was liberated by the British, not the Russians. And Sudoplatov never actually calls the scientists spies--he just implies that they were.

Oppenheimer, Fermi, Bohr, Szilard and Gamow all are dead, although Oppenheimer was exonerated of any disloyalty charges. And Sudoplatov himself, in the hospital until recently, has remained quiet through the fray.

At the same time, the Schecters--and Little, Brown & Co., the publishers of “Special Tasks”--are standing their ground. The co-authors argue that it was intended mainly as an oral history, and that it should not necessarily be taken as fact.

But the controversy about the book goes on, with hints that the flap may soon spark an official investigation. As the American Physical Society said, the accusations “are made by a man who has characterized himself as a master of deception and deceit.”