Abstract: A steam generator in which the heat-carrying fluid is a liquid metal and the detection of leakages is carried out by sampling the liquid metal. The end of the steam generator through which the liquid metal enters comprises a tube plate (2), a thermal protection plate (10) and a hollow flow sill (22) constituting the end part of the bundle case (4). Tubes (20) for protecting the tubes (3) of the bundle are placed around each of the tubes (3) between the protection plate (10) and the tube plate (2), the space (17) between these two plates being closed on its periphery by a sleeve (15). The hollow sill (22) communicates with the space (17) through tubes (27) and with the inner volume or the bundle case (4). A liquid metal take-off device (31, 32) is placed in the hollow sill (22). The invention applies in particular to steam generators of fast neutron nuclear reactors cooled with liquid sodium.

Abstract: A reactor vessel filled with coolant fluid is divided by a wall into an upper region and a lower region which contains the reactor core, part of the coolant fluid in the upper region being injected into the lower region. The injection flow rate is regulated as a function of the variations in pressure in the lower region by means of a baffle-plate container which communicates with a leak-tight chamber and with a storage reservoir, a flow of fluid from the chamber to the reservoir being established only at the time of a reduction in the rate of injection into the container. The reactor can be employed for the production of hot water which is passed through a heat exchanger and supplied to a heating installation.