Atomic Spy

by Nancy Thorndike Greenspan

  Thomson created a technical panel and put Peierls and Frisch on it. With their naturalization a year later, they became full members, Peierls as the leading mathematical physicist.

  Born and Fuchs had not needed Peierls to identify the nature of the project Fuchs would be working on. Both knew that Peierls was involved in atomic research. Appealing to Fuchs’s ideological leanings, Born had tried to dissuade him from taking the job. He described the discussion to his son, Gustav, a couple of years later:

  When Fuchs went to Birmingham to join the uranium people, I had a serious talk with him. I told him that if they succeeded it would mean a new concentration of power in the hands of a few, and very likely the wrong ones, capitalists and nationalists; I warned him who confessed to be a communist that the result of this work would mean a strengthening of capitalism. He answered that it had to be done as they knew that the Germans [were doing] it.

  For Fuchs, the top consideration was to destroy the Nazis by any means necessary. He later wrote down his own thoughts on the question of building a bomb:

  And so all illusion of a neutral or value-free science died overnight with the serious question that also required me to make a personal decision in 1941, as I received the invitation to collaborate on the English atom bomb project: “Would the power be used for good or evil? How great is the danger of Hitler’s fascism? How great are the dangers of this frightening weapon in a world torn apart?”

  On May 31, 1941, he arrived in Birmingham to begin his position with Peierls.

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  —

  Rudi and Genia Peierls lived in the well-to-do suburb of Edgbaston on the southwest side of Birmingham, a pleasant, relatively quiet area compared with the rest of the city, one of the country’s main manufacturing hubs. In wartime, this meant that the city’s industrial might was focused on weapons, supplies, and the famed Spitfire fighter plane, which made Birmingham a prime target for German bombers. By the end of May, when Fuchs arrived, the deadliest raids were over, but not all. He wrote to Born to describe a bomb that blew out windows at the university.

  The Peierlses’ white house, neo-classically themed, had plenty of space, and Klaus became their lodger. They found him pleasant, courteous, and even-tempered. “Rather silent” unless asked a question, said Peierls, and then he gave a “full and articulate answer.” Genia found him less garrulous and called him “Penny in the Slot” Fuchs. “You put your penny in and get a word back.”

  Russian-born, Genia had a degree in physics and an outsized personality often labeled effusive and loud, but she was equally warm and caring. The Peierlses, along with other physicists, had shipped their two children to the safety of Canada. Klaus helped to fill up the house. He became almost a surrogate child as Genia sewed on buttons for him and cared for him when he was sick.

  Peierls was enthusiastic about Fuchs from the start. On the day the young man arrived, Peierls wrote to Otto Frisch, “I must not tell him anything yet about the purpose of the work, but even so, this is a great help.” In fact, Fuchs far exceeded expectations.

  Within the first week, Fuchs had recalculated how the neutrons ejected by the atoms would scatter, creating more hits than previously assumed, and theorized a reduction of the required critical mass—the amount of U-235 needed for a sustained chain reaction—by a factor of four. Two months later, the two men were fleshing out the theoretical properties of different methods to separate the fissile material U-235 from the more abundant uranium isotope U-238. Even though Fuchs was ill in June and later too—at least one of his problems was an eye infection—they made rapid progress. For Peierls, he was the perfect fit, “quick on the uptake, flexible, and willing to look at new problems.” Peierls didn’t think he could have made a better choice.

  By August, Klaus was well enough to travel to London again to meet up with Simon Kremer, the Russian official whom he had met in the spring with Kuczynski and Kahle. Klaus called Kremer “Alexander,” and they met in the evening, mostly on weekends, and only a few times. The exchange of papers, wrapped in packing paper or in an envelope, happened quickly at a crowded bus stop or on a dark, quiet residential street where Kremer arrived on foot. Klaus handed over only what he himself produced. Until he had signed the Official Secrets Act, a document that restricts communication of confidential government information, he was restricted from classified research, and although Peierls was loose with that restriction, some material was kept from him.

  Fuchs was fully committed to supporting British efforts toward inventing an atomic bomb before Hitler did. He was equally committed to supporting Russia and communism.

  By this time, the German-Soviet pact had disintegrated as almost four million German soldiers attacked Russia on June 22, 1941, in Operation Barbarossa. Russia became a strong ally of England and France and, much to the German military’s surprise, did not crumble under the onslaught as had every other nation. But successful Russian resistance wasn’t a certainty. Stalin pleaded for England to divide German forces by opening up a second front. The Allies didn’t listen. Those such as Fuchs saw this rebuff as a desire for the two armies to destroy each other.

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  —

  In October, Fuchs received his work permit from the Alien War Service Department, and he was able to become an official government employee. He didn’t have access to secret research, but it didn’t matter. He didn’t really need that for the most part. His research with Peierls created many of the secrets.

  The MAUD Report, initiated the year before by Peierls and Frisch’s memo, was issued in September 1941 after a few months of wrangling. It confirmed that an atomic bomb was feasible, and it ignited the government’s major push to build one. The code name for the project was the purposefully nondescript Tube Alloys.

  The British shared the report with the Americans, and it gave them the same sense of urgency. Here was a report by respected scientists predicting that with a method called gaseous diffusion, U-235 could be separated out from U-238, increasing its density and enabling a runaway chain reaction. They could build an atomic bomb and affect the outcome of the war. Until this time, the Americans had made the same assumptions as the British and did little research, but on reading the MAUD Report, they sought out President Roosevelt to create a partnership on the bomb with the British. He authorized a letter to Churchill, who greeted the proposal with little enthusiasm. Churchill saw the British superiority in this field as leverage to use over America and was uncertain about how much help and information to give them. From that time on, the Americans went forward on their own.

  * * *

  —

  Gaseous diffusion, already used for other purposes by this time, required filtering uranium gas through a series of porous barriers to separate U-235 from U-238. U-235, the lighter of the two molecules, would pass through the filter more rapidly than U-238 and enrich the gas with U-235. The lighter isotope would be only marginally more abundant in a sample of gas that had passed through one or even several such filters, and successive passes, on the order of thousands of interdependent ones, were needed to enrich the gas sufficiently to create a chain reaction.

  The basic concept was somewhat straightforward; the details were devilish. Multiple problems had to be worked out: the types of pumps used to circulate the gas; pressure ratios between the various spaces so as to maintain a steady state; leakages and impurities in the metals; the design of the semiporous membrane used as a filter so that it didn’t clog or tear; prevention of the corrosive gas creating rust. The person who ran many of the experiments to address these problems was Francis Simon at Oxford, the chemist who had warned Churchill of the need for research on U-235. Well before Fuchs arrived in Birmingham, Simon had conceived of using the diffusion approach.

  In Birmingham, Peierls and Fuchs focused on the theoretical calculations. When Simon asked if it was better to use a continuous or discontinuous pump, they measured the effects of the differ
ent assumptions. Letters, memos, and exhaustive research papers constantly flowed between them and others in their labs and departments, delivering the calculations, offering opinions and insights, and raising objections—all bound by the Official Secrets Act except, as yet, Fuchs. Peierls, and now Fuchs, were part of a network of top physicists. They plowed through the research and calculations with a group at the university and at Peierls’s home. At night Fuchs often toiled away in his room.

  Their work was so extensive that later in November 1943 the Peierls, Fuchs, and Simon collaboration resulted in an application for a patent on their design for gaseous diffusion, “Cascade of Cascades,” the repetitive filtering method to enrich the uranium gas.

  Hanging over their efforts was the question of what the Germans were doing. Fuchs and Peierls examined German science journals looking for clues—studying lists of lectures and articles for changes in locations or research interests; listening for rumors on the top physicist Werner Heisenberg’s activities; asking colleagues to read particular articles perhaps relevant to the development of a bomb. The investigation was ongoing, inconclusive, and, as Peierls later said, ultimately “in vain.” It didn’t answer whether German scientists had shifted their focus to developing an atomic bomb.

  * * *

  —

  In the first part of 1942, Kremer was recalled to Russia, and Klaus had no contact, so Kuczynski made another introduction for him. This time it was a young woman, code name Sonya, who in real life was Ursula Kuczynski, one of Jürgen’s five sisters. Under various pseudonyms, she had been a stellar operative for the Russians since the early 1930s. Jürgen made the contact hastily without notifying Moscow Center, but they went along.

  Sonya and Klaus first met at a café across from the train station in Birmingham. After that they met on a country road near Banbury, seemingly two young lovers walking arm in arm down a rural lane. The transfer took two minutes; they spent half an hour walking so as not to attract attention. The meeting times, mostly on weekend afternoons, depended on the train schedules. Sonya had a regular arrangement to pass the material to another agent for submission to Moscow.

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  Fuchs didn’t limit himself to the environs of the Peierlses’ home in Edgbaston or meetings with Sonya. The city of Birmingham had something to offer—a branch of London’s Free German League of Culture that he frequented. Kuczynski turned up in Birmingham several times as well for various events. Any meetings between them aren’t recorded, but given the involvement of both in the KPD, it’s highly probable. Czech friends from internment brought him to their special club too. The spirit of the internment brotherhood and the British KPD quietly permeated his life in Birmingham.

  On June 18, 1942, Fuchs signed the Official Secrets Act. Peierls immediately sent memos to the staff that Fuchs now had authority to discuss “matters of relevance” with the Birmingham team and others in the Tube Alloys work. A month later, Fuchs became a naturalized British citizen and swore an oath of allegiance to the Crown.

  An in-depth review by MI5 had preceded this new status. Fuchs’s security file, holding evidence from the Gestapo that damned him as a “notorious Communist,” created consternation among the MI5 officers. Any information from the Gestapo, though, raised suspicions of reliability. MI5 officers questioned employing him on sensitive war research, but with pressure from the research community and the obvious need for scientific talent, they decided that they had to take the risk.

  * * *

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  Throughout the early war years, Churchill had used all his wiles to persuade Roosevelt to enter the war, but in spite of them, he only gained arms through the Lend Lease program in return. When the Russians didn’t collapse from the German onslaught in June 1941, Churchill and Roosevelt realized that the world order might change—and Churchill saw an opportunity to pull the United States into the war. The two leaders met in Newfoundland to sign the Atlantic Charter, a joint declaration mainly on the postwar international system, stating principles on trade, territorial acquisition, self-determination, and freedom of the seas, as well as economic welfare standards. Churchill wanted the agreement to create public support to propel the Americans into the war.

  News of the charter didn’t move the Americans to enter in, but the Japanese attack on Pearl Harbor, on December 7, 1941, did.

  With the Americans’ burgeoning commitment to atomic research, large resources, and no significant worry of being invaded or bombed, some in England recognized that in time they could lose their lead and be left in the Americans’ backwash. Sir John Anderson, who had realized the errors of internment and now, as lord president of the council, was running the country’s domestic agenda, sent a memo to Churchill urging cooperation with the Americans:

  We must . . . face the fact that the pioneer work done in this country is a dwindling asset and that, unless we capitalise it quickly, we shall be outstripped. We now have a real contribution to make to a “merger.” Soon we shall have little or none.

  The British establishment had debated whether it had the resources to undertake the necessary infrastructure for an atomic research program by itself. A gaseous diffusion plant was a huge structure and would be visible and within reach of the Luftwaffe any place in Britain. Only a physical plant, however, would offer the answer to the essential question: Could the design yield sufficient U-235 to create a chain reaction in an atomic bomb? Geographically, America would be much safer, but if the two countries worked together, would it be a loose collaboration or a joint project?

  The British and Americans reached consensus on a mutual effort to build an atomic bomb in August 1943, when the two countries signed the top secret Quebec Agreement, which was not made known even to the U.S. Congress. There were five basic statements, the first of which was not to use it against each other. Two others required mutual consent: for using the bomb on a third party and for giving information to a third party. One recognized “the heavy burden of production falling upon the United States” and, as a result, gave it decision-making power over which industrial or commercial advantages would be shared with Great Britain. The last determined the nature of the collaboration, in particular the “interchange of information,” which specified that it be kept “in the same sections of the field.”

  This agreement was consonant with the order of General Leslie Groves, head of the U.S. project, to compartmentalize information. Information in a specific research area was shared within that area only. John Anderson understood General Groves’s goal:

  He looks on co-operation as a means of speeding up the American full-scale effort. He sees no need nor obligation for reciprocity in the sense of giving us information which might be of help to us.

  As Rudi Peierls summed up, the agreement didn’t specify mutual trust.

  CHAPTER 12

  Manhattan Project, New York 1943

  On December 3, 1943, three members of the forty to fifty in the British scientific mission—the physicists Rudi Peierls and Klaus Fuchs, along with the chemist Frank Kearton—arrived at the port of Norfolk, Virginia. Their trip across the Atlantic on the troopship Andes—an ocean liner built in 1939 and, when war broke out, immediately refitted to carry four thousand troops—was uneventful. The threat of U-boats was not nearly as bad as when Fuchs had crossed on the Ettrick three and a half years before.

  The three men took the train to Washington, D.C., some hours away, met with their new boss, General Leslie Groves, filled in paperwork, and headed to New York City. So began their sojourn in America—working for what the United States officially named the Manhattan Engineer District, a frenzied drive to beat the Germans to an atomic bomb.

  The Army Corps of Engineers, in the person of General Groves, controlled the project. An engineer educated at West Point, he was very intelligent, bullish, determined, decisive, and always right. His physique, thick and powerful, matched his personality. He had complet
e command.

  The East Coast headquarters of the corps was at 270 Broadway in New York City. Its location supplied the “Manhattan” part of the project title. Footsteps away on the same block, the Woolworth Building housed the Kellex Corporation, designers of the U.S. gaseous diffusion plant. A fifteen-minute walk from there was 43 Exchange Place in the financial district and the office of the British Supply Mission shared by Peierls and Fuchs. Kearton, liaison between the diffusion research in the United States and that in England, worked from there too. Tony Skyrme, a newly minted Cambridge graduate, soon joined them to assist with calculations. Proximity created a pressured and close work environment. The geographic outlier was a group of physicists at Columbia University, on the Upper West Side, who mostly consulted with Fuchs.

  Meetings between the British team and Kellex began immediately on December 7. General Groves had been assured by the British representatives in the United States, as an Army Corps of Engineers memo on the eighth stated, that “all these people have been cleared by the British Security.” U.K. officials had run a “special clearance” on those working in the United States. Accordingly, they received “District Identification Cards” that gave their British affiliation and allowed them access to facilities in the District. They needed special permission to access “particular classified information or restricted areas.” In fact, the latter permission was hardly special—just a sheet of onionskin paper containing name, rank, name of facility to visit, and date. Permission was granted automatically; otherwise, British personnel threatened to “take it to the White House.”