Patent Number: 040509869
Section: claims

1. 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:  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. vi. means for affixing the lower portion of each said column to said upper and lower plates; 2. The liquid metal cooled nuclear reactor of claim 1 wherein said means for affixing each said column to said upper and lower plates comprise a plurality of ribs welded to said column and at least one of said upper plates and lower plates and further comprises a plurality of tubes concentrically aligned with and welded to said column and welded to said upper and lower plates. 3. The liquid metal cooled nuclear reactor of claim 1 wherein said chimney includes a circumferential groove about its periphery and an outwardly extending chimney ledge below said groove and wherein said means for mechanically affixing said chimney to said weldment are positioned above the uppermost of said upper plates and comprises a cylindrical first extension concentrically surrounding said chimney, said first extension being welded to said weldment and having a ledge for supporting a split ring key, said key tightly engaging said circumferential groove and being circumferentially surrounded by a locking band, said extension further having an inwardly extending shoulder below said groove, said shoulder overlapping said chimney ledge, whereby upwardly acting loads on said chimney are transmmitted to said weldment through said shoulder, and downwardly acting loads on said chimney are transmitted to said weldment through said key. 4. The liquid metal cooled nuclear reactor of claim 3 wherein said outlet modules are comprised of Inconel 718, said cylindrical extension is comprised of Inconel 600 and is welded to said weldment by a second extension comprised of stainless steel concentrically aligned with said first extension. 5. The liquid metal cooled nuclear reactor of claim 4 further comprising a thermal linear comprised of Inconel 718 disposed betweeen said top ledge of said first extension and said locking band and concentrically surrounding said chimney.