The involvement of the French in nuclear research had been assured by Pierre and Marie Curie, who worked with radium. Yet there was no finance available for developing nuclear weapons during World War II and the Fourth Republic proved to be a weak and ineffective government. Members of Marie Curie’s team later worked as part of the British group in the Manhattan Project and so helped the United States to build the atomic bomb.
At the end of the war, all her native knowledge had gone and France had to begin afresh. Even so, the French reputation for scientific progress proved well-earned when the first French nuclear reactor went critical in 1948 and during the following year they were producing small quantities of weapons-grade plutonium. France carried out her first atom bomb test, the Gerboise Bleue (Blue Jerboa) on 13 February 1960 in the Sahara desert. In May 1962 an underground test of a bomb four times as powerful as the Hiroshima bomb went drastically wrong. The sealing of the shaft was blown out by the explosion, and many of the personnel were contaminated by the radiation.
China did not develop atomic weapons in World War II either, and indeed did not carry out much research into particle physics until after the war. The first Chinese atomic bomb was tested on 16 October 1964 and yielded 22 kilotons. Within three years, China had tested their ultimate secret weapon of war — a hydrogen bomb.
The People’s Republic now has an immense arsenal of nuclear weapons — and one of the main production facilities for the warheads is at Harbin, where the infamous Unit 731 was constructed during World War II.
Before the outbreak of war, two expatriate German nuclear physicists, Otto Frisch and Rudolf Peierls, had come to work on nuclear fission at the University of Birmingham under Professor Marcus Oliphant. It was believed at the time that the world’s supply of uranium would be too limited to allow the making of a nuclear bomb within a matter of years, but when they came to reconsider the problem they calculated that just a few pounds (a matter of kilograms) of uranium would be sufficient to produce a bomb of immense power. This finding was classified as top secret, for it had enormous implications for the prospects for nuclear bombs as weapons of war. Oliphant considered this to be a startling revelation, and at once communicated the findings to Sir Henry Tizard, who was chairman of the Committee on the Scientific Survey of Air Defence, and one of the top military experts in Britain. A crucial breakthrough came at the Cavendish Laboratory, Cambridge, with the discovery that plutonium-239 was a by-product of the nuclear reactions of uranium.
The result was the setting up of a committee, code named Maud because that was the name of the governess whom Niels Bohr had employed for his children. By the end of 1940, the team had discovered that the making of a bomb from radioactive uranium was possible — and, as they later concluded, not only possible but inevitable with the eternal pressure for progress. In 1941, Peierls calculated a new ‘critical mass’ for Uranium-235 (U-235) at 18lb (8kg); the amount that would be necessary to sustain an atomic reaction if surrounded by a suitable reflector to retain stray neutrons could be half as much. The British were well aware that the work on nuclear fission had begun in Germany, and they were concerned that the Nazis might already be rushing ahead at the Kaiser Wilhelm Institute. The committee produced two highly influential top-secret reports. The first was entitled On the Use of Uranium for a Bomb and set out in detail how a bomb could be made with 27lb (12kg) of radioactive isotopes that would have the explosive power of 1,800 tons of TNT. They pointed out that radioactive contamination would make the surrounding area unsafe for humans for many years, and calculated that it would cost millions of pounds to produce. The main thrust of the American research at the time was the possibility that atomic power could be used for power generation, or as an energy source for submarines, and the Maud Committee proposed that the United States — who alone had the money for this project — should look instead at making an atomic bomb.
Their second report was On the Use of Uranium as a Source of Power. They worked out how to produce an atomic reactor, and even how to moderate the rate of the reaction with graphite rods. They concluded that this system could produce an endless supply of heat and electricity for the future, but (with the demands of a world war) there were no resources available to develop the idea any further in Britain at present. Research went ahead on a shoe-string budget under the code name Tube Alloys in Britain, while the secret reports were sent to the Americans for their response — yet nothing happened. Eventually an emissary was sent to find out what was being decided, only to find that the reports had been sent to Lyman Briggs as Director of the top-secret United States Uranium Committee. He was described by the British as ‘inarticulate’ and it turned out that he had not understood the scientific reports, so he had just locked them away in the office safe.
When the truth was revealed, it was agreed that the atom bomb would cost $25,000,000 and, although Tube Alloys could see how to make a bomb, the project lacked spare facilities. Even though the British handed over all their knowledge to the United States, the remarkable Calder Hall reactor in Cumbria (near the English Lake District) became the first nuclear power station in the world to deliver commercial quantities of electricity for public consumption in 1956, following the Russian pilot experiment that began in 1954. Meanwhile, a British atomic bomb was eventually manufactured and was detonated on 3 October 1952 at the Montebello Islands off the coast of Western Australia.
Although little is said of it now, the Canadians were also in the forefront of following up the revelations about the atom. Their scientists were concerned because crucial observations were being published by expatriate German nuclear scientists; it was feared that German science was secretly pressing ahead, and the Canadians were convinced for a time that there would be a Nazi atom bomb — and that would end the war with Germany as the victor. The early experiments in Ottawa demanded supplies of heavy water. This strange-sounding substance is an isotope of the water with which we are so familiar. Normal water, H2O, is composed of atoms of oxygen and hydrogen. Normal hydrogen atoms contain a proton as the nucleus and a single electron orbiting round. Heavy hydrogen (deuterium) has an extra neutron in the nucleus — it contains a proton and a neutron. The extra neutron is important in regulating nuclear reactions. Heavy water is very like normal water, and indeed is only very slightly more dense. Almost of all the heavy water in existence at the time was 407lb (185kg) that French scientists had obtained from a Norwegian hydroelectric plant. The nuclear physicists in charge of the research, Hans von Halban and Lew Kowarski, escaped to England, bringing this with them — at the time, almost all the heavy water in the world. They planned to use the heavy water to produce plutonium, and early experiments in Cambridge suggested it could work. It was then agreed that the British teams would work in cooperation with a team in Canada, safe from the threat of German bombing.
The nuclear research in Ottawa set out to test whether the heart of a nuclear reactor, an atomic pile, could be constructed. They set to work with a bin measuring 8ft 9in (2.7m) in diameter containing 1,000lb (450kg) of uranium oxide obtained from Eldorado Gold Mines Limited. The British chemical company Imperial Chemical Industries (ICI) gave them a grant of $5,000 and they were able to make substantial progress during 1942 — but this was overtaken when the Chicago reactor became the first in the world to function. From that time on the Canadians devoted themselves to carrying on research to support the American effort.