Obituary: Francis Perrin

Francis Henri Jean Siegfried Perrin, theoretical physicist, born Paris 17 August 1901, Visiting Professor Columbia University New York 1941-44, Representative to Consultative Assembly Algiers and Paris 1944-45, Titular Professor of Atomic Physics College de France 1946-72, High Commissioner for Atomic Energy 1951-70, Member Institut de France 1953-92, married 1926 Colette Auger (two sons, one daughter), died Paris 4 July 1992.

FRANCIS PERRIN was a theoretical nuclear physicist, a scientific administrator and the father of the French nuclear bomb. His was a loyal and idealistic service both to France and to science but a career which was not without its paradoxes.

Francis Perrin came from a scientifically distinguished and politically engaged left-wing family. He was the son of Professor Jean Perrin, a Nobel prize-winner for physics, who was an activist in the intellectual anti-Fascist movement of the 1930s as well as Minister for Scientific Research in the Popular Front government of 1936.

Perrin fils attended the Ecole Alsacienne and the Lycee Henri IV in Paris. His scientific prowess was such that he was admitted to the Ecole Normale Superieure at 17, took a doctorate in mathematical physics in 1928, passed the physics agregation, the highest competitive examination for teachers, the following year, and held the Chair of Theoretical Physics at the Sorbonne at the age of 34.

Perrin brought his mathematical insight to the French team working on atomic energy and in May 1939 he established the theoretical possibility of the chain reaction after a 'critical mass' had been passed. (He also thought about the possibility of thermo-nuclear reactions as a source of the sun's energy.)

The talented team was dispersed by the war but not before Perrin had become an enthusiast for the possible peaceful uses of atomic energy. Some of his schemes had a science-fiction side to them. For example, the idea of a series of nuclear explosions to create a fertile presence in the middle of the Sahara.

After the fall of France, Perrin was a visiting professor at Columbia University, New York, from 1941 to 1944. In 1943 he was made a French delegate in the United States and he then became a member of de Gaulle's Provisional Assembly in Algiers. When he returned to France at the Liberation, he became Professor of Atomic Physics at the College de France and a member of the Commissariat for Atomic Energy. He was one of the group who made 'Zoe', the first French reactor, from virtually nothing.

In 1950, the Director of the Atomic Energy Commissariat, Frederic Joliot-Curie, an unconditional Stalinist who headed a vast Communist and fellow-travelling organisation, was sacked. Joliot-Curie recommended him as a successor and he remained at this post until 1970 through the change of republics.

Despite his objections to the military use of atomic energy he was greatly affected by the failure of the United Nations to impose a general test ban and he accepted the arguments of the Prime Minister, Pierre Mendes-France, that France itself had to develop the bomb. Ironically, in the Fifth Republic his Commissariat became the agent of nuclear proliferation as France exported its nuclear knowhow.

In the 1950s Perrin was a supporter of Mendes-France and a member of the Bureau of Mendes' Union of Democratic Forces. He was an opponent of de Gaulle's return to power (he joined the Left's anti-Gaullist demonstration in May 1958) but he continued as head of the Commissariat and went on to defend French nuclear tests in the Pacific against the protests of the representatives of the islands. He continued as a public advocate of the peaceful use of the atom and remained a scourge of the opponents of nuclear power-stations. He also remained on the top secret H-bomb committee and de Gaulle apparently respected his abilities and his directness. He was on the administrative council of the Pasteur Institute from 1966 to 1969. After retirement, he remained politically active, defending Andrei Sakharov, and was President of the French Atheists' Union.

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