NUCLEAR REACTOR CONTROL ELEMENT DRIVE Russian patent published in 2003 - IPC

FIELD: devices for displacing nuclear reactor control elements. SUBSTANCE: control element drive has casing 1 accommodating drive components that functions as part of pressurized-water loop. Electromagnet unit 3 is mounted outside casing 1 and functions to transfer force through casing wall to displacement unit 2. Electromagnetic control field builds up tractive force that sets in motion movable components of displacement unit 2. These components are made in the form of latches 4, 5. Toothed rod 6 is rigidly fixed to control element. Housing of position sensor 7 is mounted on plug 9 of casing 1. Bottom part of housing 8 of position sensor 7 is disposed in rod 6 and has coils engageable with shunt which is set in motion together with rod. Length of position sensor housing should be greater than that of displacement unit 2 by minimum five diameters of position sensor housing 8. Such mechanical design of drive makes it possible to ensure coaxial arrangement of rod and displacement unit and to prevent spontaneous damage to drive rods joined to control element during installation of reactor top block. EFFECT: enhanced operating reliability of drive. 1 cl, 5 dwg