Nuclear reactor apparatus

#This invention relates generally to nuclear reactors and more particularly to a lifting, rotating, and sealing apparatus for nuclear reactors utilizing rotating members above the nuclear reactor core.

#The nuclear reactor produces heat by fissioning of nuclear material fabricated into fuel elements and assembled within a nuclear core situated in a pressure vessel. In commercial nuclear reactors, heat produced thereby is used to generate electricity. Such nuclear reactors typically comprise one or more primary flow and heat transfer systems, and a corresponding member of secondary flow and heat transfer systems. These secondary heat transfer systems are coupled to conventional steam turbines and electrical generators. A typical energy conversion process for a commercial nuclear reactor, therefore, involves transfer of heat from a nuclear core to a primary coolant flow system, to a secondary coolant flow system, and finally into steam from which electricity is generated.

#At the top of the pressure vessel, it is customary to provide a head to seal the nuclear reactor vessel and primary system. A plurality of penetrations pass through the head into the reactor vessel below. These penetrations, typical of which are control rod assemblies and transfer machines, perform functions within the nuclear pressure vessel and the reactor core.

#For a better understanding of the invention, reference may be had to the preferred embodiment, taken in connection with the accompanying drawings, in which;

#FIG. 1 is a longitudinal section of a nuclear reactor taken along the lines I--I of FIG. 2;

#FIG. 2 is a plan view of the top of the reactor head shown in FIG. 1; and

#Throughout the description which follows, like reference characters indicate like elements of various figures of the drawings.

#FIG. 1 of the drawings illustrates a typical nuclear reactor which can employ the principles of this invention. A nuclear reactor pressure vessel 10 contains a quantity of reactor coolant such as liquid sodium graphically illustrated and designated as numeral 12. The top of the pressure vessel 10 is sealed by a nuclear reactor closure head 14. In the space formed by the pressure vessel 10 and the closure head 14 and above the level of liquid coolant 12 there is maintained a quantity of an inert gas known generally as cover gas 16. The head 14 has a stationary outer member, ring 18, which is bolted to a flange 20 on the pressure vessel 10.

#The head 14 has a plurality of cylindrical rotating members such as plugs 22, 24, 26. The plug 22, of the largest diameter, is coaxial with the vessel 10. The stationary outer ring 18, horizontally surrounds and supports the large plug 22. The plug 24, of intermediate diameter, and the plug 26, of smallest diameter, are eccentric to the axis of the vessel 10. The intermediate plug 24 is horizontally surrounded and supported by the large plug 22, and the small plug 26 is horizontally surrounded and supported by the intermediate plug 24. These rotating plugs 22, 24, 26 position the fuel and control handling equipment over all vessel 10 locations.