Like their British counterparts, French scientists had been at the forefront of nuclear research before the war: Marie and Pierre Curie had experimented with radioactive radium as far back as 1898, their daughter, Irene, and her husband, Frederic Joliot, continued and advanced the Curies’ efforts during the 1930s and did pioneering work on fission. (Frederic would help to remove 185 kilograms of heavy water from Paris to Britain just in advance of the conquering Germans in 1940.) Joliot and other French nuclear scientists developed far-sighted laboratory practices in France before the war. Joliot’s chief collaborators on fission research in the 1930s were Hans von Halban, an Austrian, and Lew Kowarski, who was Russian. Both were attracted to Paris by Joliot’s reputation and his ready store of radium, first at the Radium Institute, then at Joliot’s new labs at the College de France. (Also to Joliot’s side came Bruno Pontecorvo, an engaging young Italian physicist.) The physical chemist Bertrand Goldschmidt started, in 1933, as the lab assistant of Joliot’s mother-in-law at the Radium Institute. Also in Paris at the same time were young physicists Francis Perrin, son of a Nobel Prize winner, and Pierre Auger, who would become Perrin’s brother-in-law. Goldschmidt, Halban, and Kowarski were Jews; the latter two were naturalized Frenchmen in 1939. That March, Joliot, Halban, and Kowarski split the uranium nucleus with a neutron, publishing their results, despite a plea for silence from Leo Szilard, in the British journal Nature the following month.
The German occupation scattered the nuclear community of Paris and France. While Joliot and Irene Curie stuck it out and did their best to confuse the Nazis about their work, most of the others fled. Halban and Kowarski accompanied the French heavy-water shipment aboard the British coal ship Broompark out of Bordeaux to England in June 1940. Both scientists were dispatched to the Cavendish Laboratory at Cambridge, where they drew together a handful of others and resumed their research, hoping to produce more fissions, more neutrons, and ultimately to construct reactors. The following summer, the MAUD Committee reached its conclusion that atomic bombs might be possible to build. But it seemed clear by late that summer that the apparatus necessary to build a bomb was unaffordable in the circumstance of world war and thus impractical on British soil. With collaboration with the Americans a diminishing possibility, the British decided, in the summer of 1942, to send a group to Montreal, Canada, to build a reactor. The scientists and engineers would be safe there, closer to sources of uranium, and closer to the Manhattan Project scientists, from whom they would continue to seek help. And Montreal would be a joint project, including scientists from Canada and France. Halban, the naturalized Frenchman, was eager to go, and was put in charge of the team. Kowarski, increasingly unhappy with what he saw as Halban’s highhanded treatment of him, stayed in Cambridge.
Halban had some British and Canadian researchers at his disposal. He also sought to reconstitute the group of French and European scientists with whom he had worked in Paris, or whose work in France he had known there. Frances Perrin was in New York, but Halban passed him over, fearing that he might insist on having patent rights to equipment or procedures Halban’s group would have to use without obstacle. He did recruit Perrin’s brother-in-law Pierre Auger to head his division of experimental physics. Jules Gueron, a North African Jew who had taught in Strasbourg, joined the Free French, escaped to London, then moved in with Halban and Kowarski’s group at the Cavendish. Halban brought him to Montreal to take charge of physical chemistry. Also on the scene was Bruno Pontecorvo, whom Bertrand Goldschmidt would remember as his ‘charming Italian colleague from the Curie laboratory’ in Paris. Cleared by British security services, Pontecorvo arrived in Montreal in early 1943 prepared to do physics. (Designated by the codename ‘Mlad’, Pontecorvo passed information about the project to the Russians. He would later join the British nuclear project at Harwell, then, in the summer of 1950, defect with his family to the Soviet Union.)
Bertrand Goldschmidt escaped from France in early 1941. He managed to find passage on a crowded ship to Martinique. There, he ensconced himself at an upcountry hotel run by a black woman with a Jewish father, and inhabited also by a pair of German-Jewish filmmakers and the anthropologist Claude Levi-Strauss. Weeks later, Goldschmidt found a seat on a tiny seaplane to Puerto Rico (when he arrived there he found Levi-Strauss in American custody; agents suspected his transcriptions of Amazonian language were an Axis code), then got to New York by mail boat in late May. After months of idleness, Goldschmidt took a volunteer job administering oral radioisotopes to hospitalized cancer patients. He also went to Canada to conduct experiments at a radium processing plant. Halban wrote in March 1942 and asked Goldschmidt to join him. Goldschmidt was interested, but the British were slow to give permission. When at last his hiring to Montreal was authorized, in the summer of 1942, Goldschmidt was astonished to learn that he was to be attached, with American consent, to Chicago’s Metallurgical Laboratory, to work in the chemistry lab under Glenn Seaborg. There, as the first and only Frenchman to participate in the Manhattan Project, Goldschmidt worked on uranium and plutonium extraction. He met Fermi, Oppenheimer, Groves (‘pleasant, slightly on the plump side, with an engaging manner’), was sworn many times to secrecy, and later called the experience ‘the most fascinating of my career’. Halban had finally got to Montreal himself and summoned Goldschmidt, in late October 1942, to induce plutonium while working in the project’s chemistry division.
The growing presence of Frenchmen in the Montreal lab was one of the reasons the Americans remained cool to the British scientists who had hired them. The Americans were worried mainly about security, since they viewed the French as unreliable. Groves, supported by Vannevar Bush and James Conant, refused to allow the shipment of heavy water or graphite to Canada, and insisted that nothing specific or technical about nuclear research, only basic science, be discussed with the Montreal team. Halban and the others pushed ahead anyway. In early 1943, Goldschmidt and Auger, who had previously taught at the University of Chicago, and both still in possession of university identification cards, returned to Chicago and were happily received by their former colleagues. Auger returned to Montreal with good information about Fermi’s squash court pile, which had gone critical two months earlier, while Goldschmidt pocketed a test tube, courtesy of Seaborg, containing a tiny amount of plutonium that Goldschmidt had helped to distill the previous summer. There were several further openings over the next nine months. The signing, by Roosevelt and Churchill, of the Quebec Agreement on 19 August 1943, briefly raised hopes of renewed collaboration, and it was followed by the arrival of the British team at Los Alamos. In March 1944 Chadwick managed to persuade Groves to let the Montreal group build a heavy-water reactor as a pilot plant. Perhaps to placate Groves, the British sacked Halban as project director and replaced him with John Cockcroft, who had welcomed Halban and Kowarski to Cambridge nearly four years before but who was otherwise untainted, in Groves’s mind, by association with France.
Under Cockcroft’s measured leadership, and with renewed cooperation from the Met Lab, the Montreal project went forward. In July 1944 Goldschmidt and Gueron received a shipment of metal slugs, which had been irradiated in a reactor at Oak Ridge. Experimenting with a new process to extract uranium from the slugs (the French called them ‘hot dogs’) by use of a chemical solvent, Goldschmidt went to work. Meanwhile, Charles de Gaulle, leader of the Free French and destined to play the leading role in French politics after the war, stopped briefly in Ottawa during a tour of North America. Auger, Goldschmidt, and Gueron decided that de Gaulle must learn about the bomb. De Gaulle’s representatives gave them three minutes; it was Gueron who got the honor of telling the general, and of urging de Gaulle to retain the colony of Madagascar, which held uranium. Afterwards, in a reception line, de Gaulle said to Goldschmidt: ‘I thank you. I understood you very well.’ With Halban sidelined, the pile expert Kowarski appeared in Montreal. Reactor work speeded up then, and plans progressed for a large nuclear complex, run jointly by Britain, Canada, and France, and located 200 kilometers west of Ottawa at a lonely but beautiful place Champlain had called ‘the hollow river’ during his seventeenth-century explorations. (It was now called the Chalk River.) The bombings of Hiroshima and Nagasaki startled the Montreal team but did not stop it. On 5 September 1945 the Montreal reactor went critical. Kowarski called it Zeep, for Zero Energy Experimental Pile. Chalk River opened that fall. It was a rough and ready place, appropriately christened, in November, by Canada’s Minister of Munitions and Supply Clarence Howe, who ceremonially urinated on an outside wall. Early the next year, the Americans insisted that Goldschmidt, by then the last French scientist remaining with the Canadian project, be removed to France, as he was (they claimed) jeopardizing any possibility of future Anglo-American nuclear collaboration. Goldschmidt duly left, carrying in his head a good deal of valuable information to France.
The American desire to strip the North American nuclear programs of French participants helped to reunite them in Paris. Like Josef Stalin, de Gaulle had been struck by the power of the bomb that had destroyed Hiroshima, and, though he professed ‘despair’ at the appearance of atomic weapons in the world, he wasted little time in creating a government agency to oversee nuclear issues: the Commissariat a l’Energie Atomique (CEA). It was headed by Frederic Joliot-Curie—who, with his wife, had hyphenated his surname during the war—and Raoul Dautry, an engineer and former minister of armaments who was an astute administrator and, unlike Joliot-Curie, not a communist. Theirs was a fruitful relationship, and it moved the French nuclear project briskly forward. Gueron, Auger, Perrin, Kowarski, and Goldschmidt were all involved. They set up shop at an old fort at Chatillon, on the edge of Paris. The French had contracted with Norsk Hydro for heavy water in March 1940; the shipment, 5 tons, was now delivered, six years later. Joliot-Curie also requisitioned 8 tons of uranium oxide that had been hidden from the Germans in Morocco since June 1940, and 9 tons of sodium uranate, the basis for the product called yellowcake, turned up in a boxcar in Le Havre. Laboratory glassware he purchased from a pharmacy that was going out of business. In the summer of 1947 construction began on a small reactor, the sort with which Goldschmidt and Kowarski had extensive experience. Kowarski, who liked naming machines, called the pile Zoe. Goldschmidt, using the Moroccan uranium oxide, prepared its fuel.
Zoe went critical on 15 December 1948. Kowarski had the honor of pressing the button that sent heavy water into the machine. ‘Of course,’ Goldschmidt wrote later, ‘no one could see anything, because everything took place behind the shielding provided by a thick concrete cube, several meters on each side, located at the center of a kind of shed.’ Joliot-Curie kept track of the measurements. Zoe would be put to use producing radioisotopes for research. The French program quickly expanded thereafter, with more funding and other reactors. It turned out that there was naturally occurring uranium in France, which supplemented supplies from Africa. Goldschmidt teased out the first milligram of plutonium late in 1949. Joliot-Curie had renounced the creation and use of nuclear weapons, but his open embrace of communism made him an increasing liability in France’s relations with the West, and, in the aftermath of Klaus Fuchs’s arrest in Britain in early 1950, Joliot-Curie was dismissed as head of the CEA.
Building a nuclear weapon was a related but different matter. Leslie Groves had long doubted that the French could build bombs: when he asked an American engineer about French prospects (‘How about the Frogs?’), he was told that ‘you can never get two Frenchmen to agree’, so it would be ‘damn near eternity’ before the French would have the necessary reactors up and running. Perrin, who succeeded Joliot-Curie as head of the CEA, was no more enthusiastic about nuclear weapons than his predecessor. Such high-level doubt left weapons’ work ‘only a drawing board project’ in the early 1950s, according to the CIA. Still, a 1946 poll had revealed that a majority of French citizens wanted their scientists to make nuclear weapons. De Gaulle believed, as Spencer Weart has noted, ‘that a country without nuclear weapons would not be taken seriously’, and in 1954 Prime Minister Pierre Mendes-France, smarting over the imminent loss of Indochina, declared: ‘A country is nothing without nuclear armaments.’ He thereupon authorized a program to build a weapon, a decision accelerated by the French, British, and Israeli rebuke at Suez in 1956 and affirmed by de Gaulle when he became premier in 1958. De Gaulle wanted France to have an independent military force, called force defrappe, that would include nuclear weapons. The CIA now reported that ‘most French political parties have taken the position that atomic armament is a necessary condition of independence’. Bombs conferred status, and the French craved status. By 1960 creation of nuclear weapons came second in the French military budget, trailing only funding for the suppression of the Algerian revolt. ‘Admission to the “nuclear club” is a symbol in French eyes of immediate parity with the other nuclear powers,’ concluded US intelligence. France tested its first bomb, a 70-kiloton plutonium weapon, at the Reganne Oasis in Algeria in February 1960.5