[en] Energy policies are made to answer first the national needs, but in the future they will have to follow a common global strategy which combines energy diversity and sustainable development. According to energy prospect scenarios, nuclear energy will be an essential part of the future energy sources with an increase of the present day world nuclear park by a factor 4 to 6. This dossier makes a digest presentation of the future generation ('Generation 4') of nuclear reactors with a reinforced safety and a low production of long-living radioactive wastes. The CEA (French atomic energy commission) concentrates its efforts on very high temperature and gas cooled fast systems (VHTR and GFR) and keeps its expertise on sodium-cooled fast breeder systems (SFR). It presents also the technological improvements and applications of the future systems: direct cycle turbines for a better conversion efficiency, and use of the power and heat for hydrogen production and seawater desalination. One article explains the advantages of fast reactors in terms of conversion of ²³⁵U and transmutation of minor actinides, and the last article describes the improvements made in the future fuels and materials to increase their thermal and mechanical resistance. (J.S.)