Patent Number: 041522044
Section: claims

1. In a core reactor comprising a graphite vessel having walls, and a top cover that serve as a reflector and having a filling of a mass of ball-shaped fuel and breeder elements defining a top surface and having a chamber portion therewith: the improvement in combination therewith comprising a device for controlling the power output of said core reactor and for turning off the same, said device including a first absorbing material containing component in the form of absorber rods movable into said filling of fuel and breeder elements when received in said reflector of graphite for turning off said reactor, said device also including a second neution absorbing material containing component for controlling the output of the core reactor, said second component being separate and distinct distinct from said first component and including a plurality of separate and independent plates vertically displaceable only above the filling within that chamber portion of said reflector which is defined by the top surface of said filling of fuel and breeder elements when received is said reflector of graphite, and is further defined by the top cover which is above the level of said filling of fuel and breeder elements, the depth to which said second component is movable only from said top cover into said chamber portion being limited from below by the top surface of said filling of fuel and breeder elements, and drive means in essence sufficient to overcome gravity for lifting the second absorbing material component for controlling the output of the core reactor, the second abosrbing material component being distributed over a length which corresponds approximately to height of the hollow chamber including thickness of said reflector. 2. In a core reactor in combination according to claim 1, in which said second component for controlling reactor output from above comprises a plurality of members having an area exposed above said filler component and containing neutron absorber material movable into said chamber portion above the fuel and breeder elements in order to decrease neutron flow in said chamber portion and thereby also to decrease neutron flow in said filling of fuel and breeder elements.