The Paternity of the H-Bombs: Soviet-American Perspectives


The US-Soviet Chronology and FAQ:

  • How much did the American road to the H-bomb differ from the Soviet one?
  • Could Klaus Fuchs be named a grandfather of all H-bombs? 
  • Is it true that Sakharov, the most prominent Soviet expert in H-bomb affairs, never saw the most valuable Soviet intelligence on  H-bomb - Fuchs’s espionage report of 1948? What are the reasons to believe it, and how could it be?  
  • Are there alternative views on the history of the 3rd-Idea H-bomb?

The US-Soviet Chronology of H-bomb

¨     1943, spring. The Soviet Union launched its Atomic Project under the direction of Igor Kurchatov.

¨     1945, August 20. Special Committee is formed, headed by Beria. The start of full-scale work on the A-bomb project in the USSR.

¨     1945, Fall. The first bits of intelligence on the US H-bomb research came to the U.S.S.R. as part of the A-bomb espionage.

¨     1946 Zeldovich’s group at the Institute of Chemical Physics launched research on the thermonuclear bomb based on the intelligence from the US about Classical Super design of H-bomb. The Soviet design was dubbed Truba (Tube).

¨     1946, April. Los Alamos conference on H-bomb

¨     1946, May 28. Klaus Fuchs and John von Neumann applied for a patent that included the idea to use radiation for compression, i.e. radiation implosion (within the frame­work of the Classical Super).
June. Fuchs left Los Alamos for Britain.

¨     1948, March. Fuchs passes information on the US H-bomb (Classical Super) to the Soviets.
April. Zeldovich examines this intelligence report but fails to appreciate the idea of radiation implosion (as well as American colleagues of Fuchs until 1951).

¨     1948, June. An additional theoretical group under Igor Tamm in FIAN was established to assist Zeldovich’s group in research on Truba design. Tamm’s group included his students Andrei Sakharov and Vitaly Ginzburg.

¨     1948, Fall. Sakharov invented a brand-new design for a thermonuclear bomb that employed a special way of compressing a spherically layered configuration, dubbed Sloyka (aka Layercake, aka 1st Idea in Sakharov’s Memoirs). Ginzburg then added the 2nd idea to use a specific thermonuclear explosive, LiD, dubbed LiDdochka. Since then Tamm’s group developed Layercake, while Zeldovich’s continued to research the Truba design.

¨     1949, January. Sakharov, in his first report on Sloyka, sug­gested “to use of an additional plutonium charge for a preliminary compression of Sloyka.” Later this general idea was named “atomic compression”.

¨     1949, August 29. The first Soviet test of the A-bomb.

¨     1950, January 31. Truman’s directive to create the H-bomb.

¨     1950, February 3. Klaus Fuchs is arrested.

¨     1950, February 26. Soviet directive to boost work on the H-bomb in two designs: Sloyka and Truba.

¨     1950, March. Tamm and Sakharov moves to the Installation.

¨     1950, Spring-Summer. Stanislaw Ulam suspected the infeasibility of the Classical Super design, confirmed by calculations together with Cor­nelius J. Everett and Enrico Fermi.

¨     1951, March. Teller and Ulam published the joint two-part report “Hydrodynamic Lenses and Radiation Mirrors”. Ulam’s part was based on an idea of hydrodynamic compression by A-bomb , Teller’s part was based on an idea of radiation-implosion design. It happened during preparations for the test George (May 1951) that employed the idea of Fuchs-von Neumann.

¨     1952, November 1. American thermonuclear test "Mike" based on radiation implosion, with the yield 10 megaton that stayed unknown to the Soviets for two years. 

¨     1952, November 16.  Gordon Dean, chairman of the Atomic Energy Commission announced short statement of AEC including the only reference to H-bomb: 
“In furtherance of the President's announcement of Jan. 31, 1950, the test program included experiments contributing to thermonuclear weapons research.” And he added: "Information issued by the Atomic Energy Commission on Eniwetok test series 1952 is limited to today's statement because any amplification might give aid to potential enemies. <> Making public further information as to the nature and results of these tests might injure the interests of the United States. We will make no further announcements." [Experiments for hydrogen bomb held successfully at Eniwetok // New York Times ; Nov 17, 1952, p.1]

¨     1952, December 2. Beria mentioned this test in his letter directing that creation of Sloyka "is of the first priority. Judging from certain information that has reached us, there have been tests related to this type of device."

¨     1953, January 7. On that day a prominent participant in the H-bomb project John Wheeler, on his way to Washington by train, lost a top-secret document on the H-bomb. For a long time it seemed obvious that the document had gone into the Soviet hands. Now it is quite clear that it was not the case. Most likely this incident happened to trigger the Oppenheimer affair of 1953-54.

¨     1953, August 12. The first Soviet test of the thermonuclear bomb Sloyka (Joe-4), with the yield 0.4 megaton.

¨     1954, January 14. Sakharov-Zeldovich's joint memo (16 pp., handwritten ) on “atomic compression of the super-device” as a turn in the research, but the key idea of radiation implosion was not still in sight. Apparently by then Sakharov and Zeldovich realized that the Sloyka  design had no potential for significant improvement, and that Truba (i.e. Classical Super) was a dead end. Since the latter was acknowledged in the US in 1950, it is a straightforward proof that there was no Soviet H-bomb espionage in 1950-1953.

¨     1954, March 1. American thermonuclear test "Bravo", 15 megatons.

¨     1954, Spring. Birth of the “3rd  idea” (“principle of surrounding”,  the Soviet version of radiation implosion). According to Sakharov's closest associate, “the 3rd idea emerged in the spring of 1954. It began when Sakharov brought the theorists together and set forth his idea about the high coefficient of reflection of impulse radiation from the walls made of heavy material.”

¨      1955, November 22. The first atmospheric test of the thermonuclear bomb (based on the 3rd idea).


How much did the American road to the H-bomb differ from the Soviet one?

A lot. It took one great leap to cross the chasm from nuke to thermonuke when Teller made his invention in 1951. Sakharov managed to do it in two smaller leaps: first, by inventing the "1st Idea" (= Sloyka) in 1948, then - in 1954 - by conceiving the 3rd Idea. It means that in Russia it was not exactly a chasm. Or, in other words, in 1951 Teller had to make a double invention.
Since 1948 Sakharov dealt with compression, was thinking about “atomic compression” and was just to discover a proper tool – radiation – for proper compression.
In both cases the development of the brilliant ideas required a great deal of  creative effort in science and engineering by many people. It was “The Work of Many People,” as Teller titled his article of  1955, there were 31 names of scientists in the final Soviet report on the H-bomb in 1955.
That is why the term “father of H-bomb” is not good enough. “Grandfather” is better, - it does not sound so dead serious, even if it is inapplicable to Teller and Sakharov.
Could Klaus Fuchs be named a grandfather of all H-bombs?
It is reasonable to think so at least for the first three H-bombs - American, Soviet, and British, since Fuchs contributed into all the three:

1) his invention of 1946 helped Teller to become the father of the American H-bomb in 1951;

2) his espionage report of Spring 1948 urged the Soviet leaders to boost H-bomb research, in particular, by establishing a new research team that included Sakharov; it is also probable that some ideas from the Fuchs's 1948 report contributed (via Zeldovich) into development of the 3rd idea in 1954;

3) in Britain he was the first Head of the Theoretical Division at the Harwell Atomic Energy Research Establishment.

Is it true that Sakharov, the most prominent Soviet expert in H-bomb affairs, never saw the most valuable Soviet intelligence on  H-bomb - Fuchs’s espionage report of 1948? What are the reasons to believe it, and how could it be?

To see these reasons it's worthwhile to compare two most prominent theorists of the Soviet thermonuclear weaponry, Zeldovich and Sakharov.
There is unambiguous documentary evidence that Zeldovich examined Fuchs’s report in the Spring of 1948 as well as earlier reports, while there is no evidence that he ever talked about intelligence’s involvement into the Soviet H-bomb.
On the other hand  there is no documentary evidence that Sakharov had ever access to Fuchs’s reports (there is only documentary evidence of Sakharov’s access to the pure data on DT-reaction extracted from the report and  presented as “preliminary experimental data, and these data had been published in Physical Review two weeks before!). What is even more important, Sakharov did discuss intelligence’s involvement into the Soviet H-bomb. His clear statement of his commitment to maintain secrecy together with his surmise about "imported" 0th idea (= Truba), and his reference to D. Holloway's article imply that Sakharov never saw (Fuchs’s) espionage report of 1948. Otherwise he would had known for sure that  Zeldovich's Truba design was based on intelligence and therefore by surmising on the subject he  would had breached secrecy.
Regardless all the Soviet irrationalities there were quite rational reasons not to show Fuchs’s 1948 report to Sakharov. First, this report had been examined, assessed, and therefore assimilated by Zeldovich before Sakharov was drafted into the H-bomb business. Second, Sakharov made his name in this business by inventing Sloyka design that had nothing to do with Truba design which was detailed in Fuchs’s  report. So this report was just irrelevant to development of Sloyka, and there were no good reason to disclose top sensitive information to a new person.

 Are there alternative views on the history of the 3rd-Idea H-bomb?

Yes, there are. The first who questioned the Soviet originality of the 3rd Idea was Lev Feoktistov, a Soviet H-bomb vet­eran. He based wholly on his recollections and  impressions. He worked under Zel­dovich since 1951 and knew him quite well, but he had never heard Zeldovich confirm his role in the invention of the 3rd Idea, although Zeldovich was not overly humble about tak­ing credit and priority for his ideas. A crucial fact for Feoktistov was too sudden emergence of the 3rd Idea. The idea seemed to have dropped from the sky, and he surmised that someone – presumably some American – had propelled this idea into the Soviet firmament. He concluded his 1996 article, “The Hydrogen Bomb: Who Betrayed Its Secret?” with “the feel­ing that we weren’t entirely independent at that time.” 
The amazement about the sudden emergence of the 3rd Idea could be dealt with by comparing it with the similar moment in the history of the American H-bomb. It’s known that Bethe characterized Teller’s invention of radiation implosion as an unpredictable, acci­dental discovery, a stroke of genius. If amazed Bethe could imagine that there might have been some extraneous source of Teller’s insight – such as espionage – and if Bethe had not known his long-time close friend Teller so well, he could think like Feoktistov.
Sakharov’s description of the coauthoring of the 3rd Idea does challenge historians. How could several people come up with a brainchild like this simultane­ously? And why “one of the main authors” was so unsure in his account of the invention? The comparative history of the H-bomb again shed light on these questions.
One should keep in mind that Sakharov didn’t know that, a few months before he joined the H-bomb project, Zeldovich had examined (Fuchs’s) 1948 espionage report but failed to appreciate the embryo of the 3rd Idea, aka radiation implosion (just like American colleagues of Fuchs until 1951). Although Zeldovich dismissed the idea, he must have remember some details from the Fuchs’s report, and as soon as Sakharov, in the spring of 1954, achieved his insight on the constructive role of radiation (or the 3rd Idea), Zeldovich could add his extraneous knowledge. As an honest man of secret sci­ence, Zeldovich, could not disclose his extraneous source and could not claim coauthorship of the 3rd Idea. However, if Zeldovich did use some ideas from Fuchs’s report in developing the 3rd Idea, that would strengthen his contribution in Sakharov’s eyes, so that Sakharov’s perception of the origin of the idea had to be ambiguous. Sakharov apparently tried to describe honestly, without going into classified technical details, a picture that to him was indeed ambiguous.
The real combination of Sakharov’s actual knowledge, surmises, and lack of knowledge conforms to Zeldovich’s great appreciation of Sakharov’s talent at the time when the 3rd Idea was born. As Zeldovich put it: “I can understand and take the measure of other physicists, but Sakharov – he’s something else, something special.” Zeldovich grasped Sakharov’s uniqueness when they were working together on the 3rd-Idea H-bomb.
Quite recently, two specific scenarios of American involvement in the birth of the 3rd Idea were suggested.  A Soviet H-bomb vet­eran, German Goncharov, believes that in the 1954 Sakharov and Zeldovich revisited the 6-years-old Fuchs’s report and discovered there a seed idea of radiation implosion. An American veteran Tom Reed believes that the Soviets acquired the seed idea via a brand new (late by now) Soviet spy at the Los Alamos who was involved in the American H-bomb work.
Both German Goncharov and Tom Reed were very important sources and interlocutors for my research on history of the H-bomb and biography of Sakharov. However, in my view, these hypothetical scenarios are incompatible  with the whole net of available well documented facts and chronology of the Soviet H-bomb history. This incompatibility is demonstrated in details in the revised 3rd edition of my book on Andrei Sakharov that is due this year in Moscow. 
See you there, if you can read Russian.
If you can’t, you are welcome to e-ask specific questions.
Sincerely yours
Gennady Gorelik