Fluidized bed steam generator

This invention concerns a fluidised bed steam generator used with the liquid metals of breeder reactors. Its purpose is to develop a simple heat exchanger for the safe exchange of heat between the slightly radioactive liquid metal and the water and/or steam without permitting any reaction between the liquid metal and the water and/or steam. This heat exchanger includes a vessel, a first bundle of tubes placed in the vessel and receiving the primary fluid and a second tube bundle placed in the vessel at a certain distance from the first bundle of tubes and designed to receive the secondary fluid. The products, in particle form, are placed in the vessel, in the interval existing between the first and second tubes, and a gaseous means fluidises the particles to form a fluidised bed in the vessel and ensures good heat transfer between the first and second set of tubes by means of the fluidised bed