US 4,050,986 A · Nuclear reactor I

Abstract

A nuclear reactor, particularly a liquid-metal breeder reactor whose upper internals include provision for channeling the liquid metal flowing from the core-component assemblies to the outlet plenum in vertical paths in direction generally along the direction of the respective assemblies. The metal is channeled by chimneys, each secured to, and extending from, a grid through whose openings the metal emitted by a plurality of core-component assemblies encompassed by the grid flows. To reduce the stresses resulting from structural interaction, or the transmissive of thermal strains due to large temperature differences in the liquid metal emitted from neighboring core-component assemblies, throughout the chimneys and the other components of the upper internals, the grids and the chimneys are supported from the heat plate and the core barrel by support columns (double portal support) which are secured to the head plate at the top and to a member, which supports the grids and is keyed to the core barrel, at the bottom. In addition to being restrained from lateral flow by the chimneys, the liquid metal is also restrained from flowing laterally by a peripheral seal around the top of the core. This seal limits the flow rate of liquid metal, which may be sharply cooled during a scram, to the outlet nozzles. The chimneys and the grids are formed of a highly-refractory, high corrosion-resistant nickel-chromium-iron alloy which can withstand the stresses produced by temperature differences in the liquid metal. The chimneys are supported by pairs of plates, each pair held together by hollow stubs coaxial with, and encircling, the chimneys. The plates and stubs are a welded structure but, in the interest of economy, are composed of stainless steel which is not weld compatible with the refractory metal. The chimneys and stubs are secured together by shells of another nickel-chromium-iron alloy which is weld compatible with, and is welded to, the stubs and has about the same coefficient of expansion as the highly-refractory, high corrosion-resistant alloy.

Claims5

Dependent claims

A liquid metal cooled nuclear reactor including a vessel, a head plate for said vessel, said vessel supporting a nuclear core therein including a plurality of vertically disposed core assemblies emitting coolant at different temperatures, said vessel also having inlet means below said core and outlet means above said core, and a low thermal inertia upper internals structure suspended above said core for channeling substantially all of said coolant from the top of said core to said outlet means, said suspended structure allowing said assemblies to rise vertically a preselected distance before interfering with said vertical rising, said upper internals structure comprising:

a. a stainless steel weldment including:
i. a plurality of vertically disposed elongated load bearing columns each affixed at its upper end to said head plate;
ii. an upper pair of horizontally disposed parallel plates;
iii. a plurality of upper stub tubes circumferentially welded to said upper plates;
iv. a lower pair of horizontally disposed parallel plates;
v. a plurality of lower stub tubes circumferentially welded to said lower plates, and
vi. means for affixing the lower portion of each said column to said upper and lower plates;
b. a plurality of outlet modules of a refractory corrosion resistant alloy, each said module having a flow collector disposed between said core and said weldment for collecting coolant emitted from a plurality of said assemblies, a cylindrical chimney, said chimney extending upwardly through a concentrically aligned lower stub tube and upper stub tube,
c. means for mechanically affixing said chimney to said weldment, and
d. a peripheral seal affixed to said weldment and extending about the outer periphery of said core for directing the bulk of said coolant from said assemblies into said collectors, said seal formed of a plurality of horizontally abutting blocks having a horizontal section and a plurality of vertical protrusions extending downwardly therefrom, said protrusions circumferentially surrounding the top of some of said assemblies so as to act as a core bundling device.

7 more elements

Dependencies are inferred from the claim text.

Nuclear reactor I

Life of this patent

Nuclear reactor I

Life of this patent

Abstract

Claims5