METHOD AND APPARATUS FOR POSITIONING AND REPAIRING CONTROL ROD DRIVE MECHANISM

摘要

PURPOSE: To accurately position the upper end of the housing of a control rod drive mechanism in one opening of a reactor core holding plate by combinedly using a precisely measured inclined angle and the already known length of an aligning device. CONSTITUTION: An aligning device is positioned in one opening 32 of a reactor core supporting plate 16 after the device is lowered through an upper guide plate 12. The aligning device is equipped with projecting vanes 50 which make the device to be inserted into the opening 32 of the plate 16 above the housing 14 of a control rod drive mechanism. A shaft 52 is extended to the upper end of the housing 14 from the vanes 50 and one vane 50 is engaged with a positioning pin 34 protruded from the plate 16. In addition, a housing inserting jig 56 provided on the lower end of the shaft 52 is accurately inserted into the upper end of the housing 14. The aligning device is also provided with electronic levels 58 so that the device can be used underwater. The levels 58 remotely transmit the accurate inclined angle between the upper end of the housing 14 and the corresponding opening of the plate 16 through attached cables.