Nuclear reactor with improved cooling in an accident situation

Abstract

Nuclear reactor comprising: a reactor vessel (4) designed to hold a reactor core; a primary system for cooling the reactor; a reactor pit (6) in which the vessel (4) is placed; an annular channel (16) surrounding a lower portion of the reactor vessel (4) in the reactor pit (6), said channel (16) being intended to act as a thermal shield in normal operation and intended for the ascending flow of a liquid in the event of an accident; a reserve of liquid capable of filling the reactor pit; a reactor containment (22, not drawn); a manifold (26) for collecting the steam generated at an upper end of the reactor pit (6), said manifold being separate from the containment (22); a circulating pump (40) capable of generating a forced convection of the liquid in the annular channel (16); and a lobe pump or steam piston machine or turbine (32) for actuating the circulating pump (40) and capable of generating forced convection by means of said collected steam.

Description

technical field [0001] The present invention relates to a nuclear reactor with improved cooling in accident situations, more particularly to improved external cooling of the reactor vessel defined as the reactor core during severe accidents. Background technique [0002] In general, a nuclear reactor includes a reactor core that contains nuclear fuel (for example in the form of fuel rods or plates) confined in a vessel, and water that is capable of entering and circulating in the vessel to carry out the products of the nuclear reactions taking place in the reactor core. heat and discharge the primary circuit of the container. The reactor also contains a secondary loop in which water is also circulated. Although the primary and secondary circuits are independent of each other, heat exchange occurs between the water of the primary circuit and the water of the secondary circuit flowing from the vessel. Water in the secondary circuit is evaporated and sent to a turbine to gene...

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Problems solved by technology

[0018] Moreover, for reactors over 600 MW, especially where a metal layer is formed above the slag bath oxide, thermal energy is concentrated in the vessel region due to its horizontal convection and high heat transfer coefficient with the vessel wall, a phenomenon known as "focusing effect", which causes perforation of the vessel wall at the point where the energy of the slag bath is concentrated

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