초록 ▼

Device for the emergency removal of the heat dissipated by a fast breeder nuclear reactor when shut down, comprising a liquid-liquid heat exchanger immersed in the vessel of the reactor and a liquid-air exchanger for the cooling of the secondary liquid of the latter exchanger. The liquid-liquid comp

Device for the emergency removal of the heat dissipated by a fast breeder nuclear reactor when shut down, comprising a liquid-liquid heat exchanger immersed in the vessel of the reactor and a liquid-air exchanger for the cooling of the secondary liquid of the latter exchanger. The liquid-liquid comprises a casing composed of a sleeve (18,19) having openings (21,22) for the natural circulation of the cooling fluid of the reactor in contact with the tubes (25) of a nest (20) disposed in the casing of the exchanger. Each of the tubes (25) includes a straight input section and a long straight return section, separated by a helically wound section forming a loop with a low number of turns, inclined to a small extent with respect to the horizontal plane. The coil diameter of the tubes (25) is constant and identical for all the tubes and very slightly less than the interior diameter of the sleeve (18,19). The invention applies in particular to liquid sodium-cooled fast breeder nuclear reactors.

대표청구항 ▼

A device for the emergency removal of the heat dissipated by a fast breeder nuclear reactor when shut down, said reactor having a core composed of fuel assemblies, immersed in a liquid metal filling the reactor vessel and constituting the primary cooling fluid taking up the heat of the reactor, said

A device for the emergency removal of the heat dissipated by a fast breeder nuclear reactor when shut down, said reactor having a core composed of fuel assemblies, immersed in a liquid metal filling the reactor vessel and constituting the primary cooling fluid taking up the heat of the reactor, said heat removal device comprising at least one liquid-liquid heat exchanger composed of an external casing (15, 18, 19) open at its lower part and having openings in its wall immersed in said primary cooling fluid and enclosing a bundle (20) of tubes (25) fixed on at least one tube plate (12, 14) inside said casing (15, 18, 19) and each comprising a rectilinear part, then a helically wound part and another rectilinear part and inside which a liquid circulates whose cooling is provided outside the casing of said heat exchanger, said external casing comprising an elongate cylindrical sleeve disposed with its axis vertical in said reactor vessel having a thickness such that it remains substantially undeformed under stresses, and said tubes constituting said bundle each comprising a vertical straight liquid input part and a vertical straight liquid return part extending parallel thereto along substantially the whole length of said tube in the vertical direction and held in position by a plurality of transverse cross-pieces fixed on an internal face of said casing and an intermediary helically wound part having only about one loop and a half, said loops of all the tubes of said bundle being disposed in substantially horizontal planes with their axes along the axis of said cylindrical sleeve and having a same diameter which is substantially equal to the internal diameter of said sleeve.