Patent Number: 052992420
Section: claims

1. In a nuclear reactor having a core operating in the fast neutron energy spectrum where criticality control is achieved by neutron leakage, a reactor control system comprising: a) dual annular, rotatable reflector rings, the rings including an inner reflector ring and an outer reflector ring, the reflectors concentrically assembled, surrounding the reactor core, and each reflector ring including a plurality of openings, the openings in each ring capable of alignment with each other;  b) means for independent driving of each of the annular reflector rings such that reactor criticality can be initiated and controlled by rotation of either reflector ring such that the extent of alignment of the openings in each ring controls the reflection of neutrons from the core. 2. The reactor control system of claim 1 wherein the openings in each reflector ring are of a size to ensure that when the openings in each reflector are not aligned, the reactor is operational due to the reflection of neutrons back to the reactor core where the neutrons initiate and sustain the fission process, and when the openings in each reflector are aligned, the reactor is shutdown due to insufficient reflection of neutrons to the reactor core to allow the reactor to attain criticality. 3. The reflector ring of claim 2 wherein the means for independent driving of each reflector ring includes inner reflector drive means and outer reflector drive means. 4. The reflector ring of claim 3 wherein the inner reflector drive means and the outer reflector drive means each include a reflector drive shaft operably connected to a pinion and ring gear structurally connected to the inner or outer reflector, such that rotation of either drive shaft causes the pinion to turn its respective ring gear to thereby rotate the associated reflector to control neutron leakage from the reactor core.