Dark Sun: The Making Of The Hydrogen Bomb

assassination of Central Committee member Sergei Mironovich Kirov in December 1934 as Stalin moved to eliminate all those in power whose authority preceded his imposition of one-man rule. “Stalin killed off the founders of the Soviet state,” writes the high-level Soviet defector Victor Kravchenko. “This crime was only a small part of the larger blood-letting in which hundreds of thousands of innocent men and women perished.” According to a Soviet official, the slaughter claimed not hundreds of thousands but millions: “From 1 January 1935 to 22 June 1941,19,840,000 enemies of the people were arrested. Of these 7 million were shot in prison, and a majority of the others died in camp.” Exiled Soviet geneticist Zhores Medvedev notes that “the full list of arrested scientists and technical experts certainly runs into many thousands.” Kharkov, where Kirill Sinelnikov had moved to direct the high-voltage laboratory after studying at Cambridge, lost most of its leaders, though Kurchatov's brother-in-law himself was spared.

The British Royal Society had funded an expensive laboratory in its own dedicated building in the courtyard outside the Cavendish for Peter Kapitza. Perhaps suspecting that he intended to defect, the Soviet government detained him during a visit home in the summer of 1934 and barred him from returning abroad. His detention shocked the British, and for a time he was too depressed to work, but the Soviet government bought his Cambridge laboratory equipment and built a new institute for him in Moscow. (A frustrated Kapitza had to order such unavailable consumer goods as wall clocks, extension telephones and door locks from England.) Eventually he went back to work, as he wrote People's Commissar Vyacheslav Molotov, “for the glory of the USSR and for the use of all the people.” Niels Bohr, the Danish physicist, after visiting him in Moscow in 1937, observed that “by his enthusiastic and powerful personality, Kapitza soon obtained the respect and confidence of Russian official circles, and from the first Stalin showed a warm personal interest for Kapitza's endeavors.”

Kapitza's golden captivity was not yet terror, but he needed all his connections when Lev Landau was arrested in April 1938, convicted of being a “German spy” and sent to prison, where he languished for a year and became ill. Landau had been working at Kapitza's Institute for Physical Problems. Kapitza determined to save him, writes Medvedev:

After a short meeting with Landau in prison, Kapitza took a desperate step. He presented Molotov and Stalin with an ultimatum: if Landau was not released immediately, he, Kapitza, would resign from all his positions and leave the institute… It was clear that Kapitza meant business. After a short time Landau was cleared of all charges and released.

In old age, Edward Teller would cite his friend's arrest and imprisonment as one of three important early influences on his militant anti-Communism (the other two, Teller said, were the Great Terror itself and Arthur Koestler's novel Darkness at Noon): “Lev Landau, with whom I published a paper, was an ardent Communist. Shortly after he returned to Russia, he went to prison. After that he was no longer a Communist.” Communist or not, Landau continued to work at Kapitza's institute in Moscow.

Not even Ioffe escaped the general harrowing. “Although the majority of [Soviet] scientists realized the importance of work in the field of nuclear physics,” writes Alexandrov, “the leadership of the Soviet Academy of Sciences and of the Council of People's Commissars believed that this work had no practical value. Fiztekh and Ioffe himself were heavily criticized at the 1936 general assembly of the Academy of Sciences for ‘loss of touch with practice.’” With the Great Terror destroying lives all around them, Soviet physicists understandably learned caution from such charges. “In those years,” writes Stalin's daughter Svetlana Alliluyeva, “never a month went by in peace. Everything was in constant turmoil. People vanished like shadows in the night.” Her father brooded over it all, reports the historian Robert Conquest: “Stalin personally ordered, inspired and organized the operation. He received weekly reports of… not only steel production and crop figures, but also of the numbers annihilated.” Shot in the back of the head at Lubyanka prison, truckloads of bodies to the crematorium at the Donskoi Monastery, smoking ashes bulked into open pits and the pits paved over. That was the era when Osip Mandelstam suffered three years’ exile and then five years in a gulag camp — five years that killed him — for writing a poem, “The Stalin Epigram,” the most ferocious portrait of the dictator anyone ever devised:

Our lives no longer feel ground under them.
At ten paces you can't hear our words.
But whenever there's a snatch of talk
it turns to the Kremlin mountaineer,
the ten thick worms his fingers,
his words like measures of weight,
the huge laughing cockroaches on his top lip,
the glitter of his boot-rims.
Ringed with a scum of chicken-necked bosses
he toys with the tributes of half-men.
One whistles, another meows, a third snivels.
He pokes out his finger and he alone goes boom.
He forges decrees in a line like horseshoes,
one for the groin, one the forehead, temple, eye.
He rolls the executions on his tongue like berries.
He wishes he could hug them like big friends from home.

Igor Kurchatov organized the initial Soviet study of nuclear fission at Fiztekh in the early months of 1939, following Joliot-Curie's letter to Ioffe and confirmation of the discovery in scientific journals. Landau's remark to Peierls in 1934 about secondary neutrons points to one universal line of inquiry: examining whether the fission reaction, which a single neutron could initiate, would release not only hot fission fragments but additional neutrons as well. If so, then some of those secondary neutrons might go on to fission other uranium atoms, which might fission yet others in their turn. If there were enough secondary neutrons, the chain reaction might grow to be self- sustaining. Joliot-Curie's team in Paris set up an experiment to look for secondary neutrons in late February; in April the French reported 3.5 secondary neutrons per fission and predicted that uranium would probably chain-react. Enrico Fermi, now at Columbia University in flight from anti-Semitic persecution (his wife Laura was Jewish), and emigre Hungarian physicist Leo Szilard, also temporarily working at Columbia, soon independently confirmed fission's production of secondary neutrons. At a Fiztekh seminar in April, two young members of Kurchatov's Fiztekh team, Georgi Flerov and Lev Rusinov, reported similar results — between two and four secondary neutrons per fission. (In 1940, Flerov and Konstantin A. Petrzhak would make a world-class discovery, the spontaneous fission of uranium, a consequence of uranium's natural instability and a phenomenon that would prove crucial to regulating controlled chain reactions in nuclear reactors. Before the young Russians succeeded, the American radiochemist Willard F. Libby, later a Nobel laureate, had tried two different ways unsuccessfully to demonstrate spontaneous fission.)

Down the street at the Institute of Physical Chemistry, Yuli Khariton and an outstanding younger colleague, theoretician Yakov B. Zeldovich, began exploring fission theory. “Yuli Borisovich notes a curious detail,” Zeldovich recalled: “we considered the work on the theory of uranium fission to be apart from the official plan of the Institute and we worked on it in the evenings, sometimes until very late.” Zeldovich was a brilliant original — “not a university graduate,” comments Andrei Sakharov; “… in a sense, self-educated” — who had earned a master's degree and a doctorate “without his ever bothering about a bachelor's degree.” “We immediately made calculations of nuclear chain-reactions,” Khariton remembers, “and we soon understood that on paper, at least, a chain-reaction was possible, a reaction which could release unlimited amounts of energy without burning coal or oil. Then we took it very seriously. We also understood that a bomb was possible.” Khariton and Zeldovich reported their first calculations in a seminar at Fiztekh in the summer of 1939, describing the conditions necessary for a nuclear explosion and estimating its tremendous destructive capacity — one atomic bomb, they told their colleagues, could destroy Moscow.

Theoretical physicist J. Robert Oppenheimer at Berkeley, Fermi, Szilard, Peierls in England, all quickly came to similar conclusions. “These possibilities were immediately obvious to any good physicist,” comments Robert