[en] Seventies were marked by important changes for the energy supply of France. The sharp increase of oil prices due to the first oil shock and the competitiveness and maturity of water-cooled reactors from imported American technologies, have favoured the emergence of an industrial policy that brought enduring changes on the French energy policy. In November 1973, Pierre Messmer, then prime minister, announced the construction of an uranium enrichment plant EURODIF in the southeast of France. A year later, on 6 March 1974, he announced during a TV interview, an acceleration of the nuclear program with the construction of 13 nuclear reactors totalling 13000 MW of additional capacity for EDF. During the few decades after the world war 2, a multitude of types of reactors were studied worldwide but soon, light water cooled reactor technology took over and France abandoned UNGG (natural uranium, gas cooled and graphite moderated) type reactors to adopt pressurized water reactors. The choice for the UNGG type of reactors had been imposed by prevailing circumstances: the availability of graphite and natural uranium in large supply for France without having to import them. One of the reasons of the abandon of the UNGG type of reactors was that the maximum size of such reactors was reasonably around 700 MWe which excluded any future economical gain through size effect. (A.C.)