Patent Number: 
Section: claims

1. For use in a nuclear fission reactor, a flow control assembly, comprising:a flow regulator subassembly, said flow regulator subassembly including:a first sleeve having a first hole, said first sleeve having a structure arranged to axially translate responsive to rotational engagement thereof;a second sleeve slidably inserted into said first sleeve such that relative rotation of said first sleeve with respect to said second sleeve is restricted, said second sleeve having a second hole, the first hole being progressively axially alignable with the second hole responsive to axial translation of said first sleeve; anda carriage subassembly having a structure arranged to rotatably engage said first sleeve. 2. For use in a nuclear fission reactor, a flow control assembly couplable to a selected one of a plurality of nuclear fission fuel assemblies arranged for disposal in the nuclear fission reactor, comprising:an adjustable flow regulator subassembly for modifying flow of a fluid stream flowing through the selected one of the plurality of nuclear fission fuel assemblies, said adjustable flow regulator subassembly including:an outer sleeve having a plurality of first holes, said outer sleeve having a structure arranged to axially translate responsive to rotational engagement thereof;an inner sleeve slidably inserted into said outer sleeve, said inner sleeve having a plurality of second holes, the first holes being progressively axially alignable with the second holes responsive to axial translation of said first sleeve; andan anti-rotation mechanism that engages said outer sleeve and said inner sleeve, the anti-rotation mechanism restricting relative rotation of said first sleeve with respect to said second sleeve and permitting axial translation of the first sleeve with respect to the second sleeve; anda carriage subassembly rotatably coupled to said outer sleeve. 3. The flow control assembly of claim 2,wherein said outer sleeve is generally cylindrical and rotatable; andwherein said inner sleeve is generally cylindrical. 4. The flow control assembly of claim 2, wherein said carriage subassembly is driven by a lead screw arrangement for rotatably engaging said outer sleeve. 5. The flow control assembly of claim 2 wherein said carriage subassembly is driven by a reversible motor arrangement for rotatably engaging said outer sleeve. 6. The flow control assembly of claim 5, wherein said carriage subassembly is at least partially controlled by a radio transmitter-receiver arrangement operating said reversible motor arrangement for rotatably engaging said outer sleeve. 7. The flow control assembly of claim 5, wherein said carriage subassembly is at least partially controlled by a fiber optic transmitter-receiver arrangement operating said reversible motor arrangement for rotatably engaging said outer sleeve. 8. A flow control assembly comprising:an outer sleeve defining therein a plurality of outer sleeve holes and having an outer sleeve engagement surface;an inner sleeve slidably insertable into the outer sleeve, the inner sleeve defining therein a plurality of inner sleeve holes that are progressively axially alignable with the plurality of outer sleeve holes;a carriage subassembly having a carriage subassembly engagement surface arranged to rotatably engage the outer sleeve engagement surface; andan anti-rotation mechanism that engages the outer sleeve and the inner sleeve, the anti-rotation mechanism restricting relative rotation of the outer sleeve with respect to the inner sleeve and permitting axial translation of the outer sleeve with respect to the inner sleeve. 9. The flow control assembly of claim 8, wherein:the outer sleeve engagement surface is threadedly defined in the outer sleeve; andthe carriage subassembly engagement surface is threadedly defined in the carriage subassembly. 10. The flow control assembly of claim 8, wherein the carriage subassembly includes a reversible motor arrangement. 11. The flow control assembly of claim 8, wherein the anti-rotation mechanism includes:a plurality of grooves defined in the outer sleeve; anda plurality of tabs defined in the inner sleeve, the plurality of grooves and the plurality of tabs being shaped to engage each other. 12. A flow control assembly comprising:an outer sleeve defining therein a plurality of outer sleeve holes and having an outer sleeve engagement surface;an inner sleeve slidably inserted into the outer sleeve, the inner sleeve defining therein a plurality of inner sleeve holes that are progressively axially alignable with the plurality of outer sleeve holes;a carriage subassembly rotatably coupled to the outer sleeve, the carriage subassembly having a carriage subassembly engagement surface arranged to rotatably engage the outer sleeve engagement surface; andan anti-rotation mechanism that engages the outer sleeve and the inner sleeve, the anti-rotation mechanism restricting relative rotation of the outer sleeve with respect to the inner sleeve and permitting axial translation of the outer sleeve with respect to the inner sleeve. 13. The flow control assembly of claim 12, wherein:the outer sleeve engagement surface is threadedly defined in the outer sleeve; andthe carriage subassembly engagement surface is threadedly defined in the carriage subassembly. 14. The flow control assembly of claim 12, wherein the carriage subassembly includes a reversible motor arrangement. 15. The flow control assembly of claim 12, wherein the anti-rotation mechanism includes:a plurality of grooves defined in the outer sleeve; anda plurality of tabs defined in the inner sleeve, the plurality of grooves and the plurality of tabs being shaped to engage each other.