Abstract: The primary coolant fluid is circulated within at least one primary loop between a steam generator and a pressure vessel. Within the steam generator, the primary fluid flows through a tube bundle and exchanges heat with a secondary fluid which is admitted in the form of water and discharged in the form of steam. After expansion within turbines and recovery in a condenser, the steam is then returned into the generator. The primary fluid circulating pumps are each driven by a turbine which is fed with steam taken directly from the steam generator or from the main outlet duct of the generator. The essential objective of the invention is to dispense with the use of an electric motor for driving each primary fluid circulating pump.

Abstract: A bundle of J-shaped tubes uniformly spaced in radial planes about the axis of a cylindrical shell is provided for the circulation of a primary fluid between on the one hand an inlet header delimited by a central tube plate and by the top dished end of the shell and on the other hand a toric outlet header which is partly delimited by the peripheral tube plate and the shell wall and is located above an annular space between the shell wall and a coaxial inner skirt. At least one nozzle for the supply of secondary fluid in the liquid state opens into the annular space and a lateral chamber is formed within the shell between the primary fluid inlet and outlet headers for collecting the secondary-fluid steam produced in contact with the tubes.

Abstract: A generator for the production of both superheated steam and saturated steam has an outer casing formed by an inner cylindrical shell engaged within an outer cylindrical shell, the shells being closed by dished ends. An annular header for the admission of pressurized primary water is formed between an upper annular tube plate and a partition-wall while an outlet header for the discharge of primary water is formed by a central tube plate mounted within the inner shell. A bundle of parallel tubes for the circulation of primary water extends vertically upward from the central tube plate. The end portion of each tube has the shape of a crook in order to join the tubes to the annular tube plate in uniformly spaced relation. The secondary water is admitted into the casing by means of ducts formed in the inner shell near the central tube plate. The steam generated is discharged through ducts formed in the outer shell.