Patent Number: 
Section: claims

1. A positioning apparatus for a control rod drive (CRD) handling assembly for a nuclear reactor, said positioning apparatus comprising: at least one linear slide rail;  a drive screw coupled to said at least one slide rail;  an elevator movably coupled to said drive screw, said elevator comprising a bore extending therethrough sized to receive and support a control rod drive; and  at least one linear bearing attached to said elevator and slidably engaged with said at least one slide rail. 2. A positioning apparatus in accordance with  claim 1  comprising a first and a second linear slide rail, said drive screw coupled to both linear slide rails, said elevator comprising a first and a second linear bearing, said first linear bearing slidably engaged with said first linear slide rail and said second linear bearing slidably engaged with said second linear slide rail. claim 1 3. A positioning apparatus in accordance with  claim 2  wherein said drive screw is coupled to a first end of said linear slide rails by a first tie plate and to a second end of said linear slide rails by a second tie plate. claim 2 4. A positioning apparatus in accordance with  claim 3  wherein said first tie plate comprises a first drive screw bearing and a drive screw thrust bearing to rotatably support said drive screw. claim 3 5. A positioning apparatus in accordance with  claim 3  wherein said second tie plate comprises a drive screw bearing to rotatably support said drive screw. claim 3 6. A positioning apparatus in accordance with  claim 3  wherein said first tie plate comprises a plurality of CRD support rollers. claim 3 7. A positioning apparatus in accordance with  claim 1  wherein said elevator comprises a elevator nut received in an elevator nut recess, said elevator nut configured to engage said drive screw. claim 1 8. A positioning apparatus in accordance with  claim 7  wherein said elevator nut is retained in said elevator nut recess by said drive screw. claim 7 9. A handling assembly for a CRD for a nuclear reactor, said handling assembly comprising: a trunnion cart;  a tower coupled to said trunnion cart;  a drive screw coupled to said tower;  an elevator movably coupled to said drive screw, said elevator comprising a bore extending therethrough sized to receive and support a control rod drive; and  at least one slide rail coupled to said tower, said at least one slide rail aligning said elevator, said elevator further comprising at least one linear bearing slidably engaged with said at least one slide rail. 10. A handling assembly in accordance with  claim 9  wherein said trunnion cart comprises a plurality of wheels, a plurality of trunnion axles, said trunnion axles pivotally coupling said tower to said trunnion cart. claim 9 11. A handling assembly in accordance with  claim 10  wherein said tower comprises a plurality of pillow blocks secured to said tower, said pillow blocks pivotally coupling said tower to said trunnion cart axles. claim 10 12. A handling assembly in accordance with  claim 9  wherein said tower comprises a wheel assembly spaced from said trunnion cart. claim 9 13. A handling assembly in accordance with  claim 12  wherein said wheel assembly includes at least one wheel, each said wheel pivotable from a retracted position to an extended position. claim 12 14. A handling assembly in accordance with  claim 9  wherein said tower comprises a first tie plate and a second tie plate. claim 9 15. A handling assembly in accordance with  claim 14  wherein said first tie plate comprises a first drive screw bearing and a drive screw thrust bearing to rotatably support said drive screw. claim 14 16. A handling assembly in accordance with  claim 14  wherein said second tie plate comprises a second drive screw bearing to rotatably support said drive screw. claim 14 17. A handling assembly in accordance with  claim 9  wherein said tower comprises a plurality of CRD support rollers. claim 9 18. A handling assembly in accordance with  claim 9  wherein said elevator comprises a elevator nut received in an elevator nut recess, said elevator nut configured to engage said drive screw. claim 9 19. A handling assembly in accordance with  claim 18  wherein said elevator nut is retained in said elevator nut recess by said drive screw. claim 18 20. A handling assembly for a CRD for a nuclear reactor, said handling assembly comprising: a trunnion cart comprising a plurality of trunnion axles;  a tower pivotally coupled to said trunnion cart, said tower sized to receive a CRD, said tower comprising a wheel assembly, a first tie plate, a second tie plate, a lower drive screw bearing, an upper drive screw bearing, and a drive screw thrust bearing;  a threaded drive screw rotatably coupled to said tower by said lower drive screw bearing, said upper drive screw bearing, and said drive screw thrust bearing, said drive screw including a drive screw operator;  an elevator comprising a plurality of linear bearings, a CRD support plate, a nut recess, and a elevator nut received in said nut recess, said elevator nut threadedly engaged with said drive screw; said drive screw retaining said elevator nut in said nut recess, said CRD support plate comprising a bore extending therethrough sized to receive and support a control rod drive; and  a plurality of linear slide rails coupled to said tower, each said slide rail slidably engaged to one of said elevator linear bearings, said linear slide rails aligning said elevator.