State of advanced model N4 - French design PWR related to the nuclear power plants in France

The French nuclear program has considerably increased over a period of twelve years. From 1974 to 1986, installed nuclear power climbed from 2 600 MWe to 45 000 MWe to reach 15 % of the electric power, from nuclear plants, in the world. The first unit of the N4 model was part of the agreed annual program of 1984 (2 units were ''launched'' in this year: 1 PWR P'4 unit and 1 PWR N4 unit), and construction started on the site of CHOOZ in the North-East of France, 24 years after that of the first PWR unit built on the same site: CHOOZ A 305 MWe Sena. This new design shows certain aspects which are the result of the experience feedback of our own installations, and comprises besides several modifications due to new safety demands, and also improvement of a technical sort, with the aim of obtaining economic benefits and a more flexible operation. The main objective which has guided the design research was the reduction in investment costs, obtained by an increase in the electrical power: this results in a power increase of the core, in certain improvements in the principal equipment of the primary circuit, and in the choice of a new design of turbine which is more compact and has a better output: The ''Arabelle'' turbine