Abstract: Apparatus for homogenizing the circumferential temperatures of the vertically axes ferrule of a component passing through the upper slab of a nuclear reactor, wherein it comprises at least one assembly forming a heat pipe describing the entire circumference of said ferrule in order to ensure the homogenization of the temperatures of said ferrule level with the assembly, means for fixing the assembly or assemblies forming the heat pipe on the inner face of the ferrule and means for ensuring a thermal contact between the assembly or assemblies forming the heat pipe and the said ferrule.

Abstract: An apparatus for thermally insulating nuclear reactor primary vessels. The apparatus includes a plurality of cylindrical reflective metal plates located within the primary vessel for thermally insulating the side walls of the vessel from the temperatures generated by the reactor. The reflective plates are radially spaced apart and are positioned in an annular inverted U-shaped chamber that traps inert gas around the reflective plates. The plates and the annular chamber insulate the side walls of the primary vessel from the temperatures generated by the reactor.

Abstract: Fast neutron nuclear reactor cooled by a liquid metal, comprising a main vessel sealed by an upper slab and within said main vessel at least one heat exchanger between the said liquid metal and a second fluid, at least one pump for circulating the liquid metal, a cylindrical inner vessel with a vertical axis and placed on flooring resting on the bottom of the main vessel, the inner vessel containing the reactor core which rests on a support bearing against the bottom of the main vessel by means of the said flooring, the liquid metal circulating from bottom to top through the reactor core, wherein the said inner vessel incorporates an internal baffle which revolves about the vertical axis of the inner vessel, said baffle comprising an upper cylindrical part adjacent to the inner vessel and arranged above the core, and a lower cylindrical part surrounding the core and having a smaller diameter than the upper part, said lower part being connected to the upper part by a frustum-shaped part, whereby the baffle con

Abstract: Apparatus for suspending thermal shielding within a nuclear reactor. The apparatus includes a plurality of horizontally deformable, interconnected links which form a chain and suspend a series of horizontally disposed equally spaced thermally reflective plates from beneath the upper horizontal boundary of a nuclear reactor. The deformable links minimize heat transfer and accommodate both seismic and differential thermal expansion of the reflective plates.

Abstract: A liquid metal cooled fast breeder nuclear reactor comprising a nuclear fuel assembly submerged in a pool of coolant contained in a primary vessel is housed in a concrete vault. A core cover structure suspended from the roof of the vault and immersed in the pool of coolant comprises a plurality of vertical tubes braced apart by perforated grid plates. An intermediate grid plate has a permeable shroud which constrains coolant passing through the perforations in the grid plate to flow transversely over the upper surface to reduce the transient temperature differential.

Abstract: Apparatus for insulating hot sodium in a reactor vessel in a pool-type nuclear reactor. The apparatus includes a flow isolated plenum in the reactor vessel for holding a stagnant quantity of sodium. The flow isolated plenum is located between a second plenum for holding hot sodium and the structural load bearing members of the reactor. The flow isolated plenum forms a thermally insulating field barrier between the hot sodium and the structural members.

Abstract: A liquid metal-cooled nuclear reactor has a reactor vessel with a cover at the top thereof and is partly filled with liquid metal up to a given surface level, the liquid metal surface and the reactor-vessel cover defining therebetween a gas-filled space, at least one quasi-tight convection barrier being disposed in the space and subdividing it in elevation.