CONTROL ROD DRIVE SYSTEM INCLUDING NUCLEAR REACTOR SEALED CONTROL ROD DRIVE MECHANISM

摘要

PROBLEM TO BE SOLVED: To provide a nuclear reactor sealed control rod drive system that achieves improvement in follow-up capability of an external driving system for an internal driving system.SOLUTION: A control rod drive system comprises an internal driving system and an external driving system. The internal driving system includes: a first ball screw 2 that is driven in rotation in a canned pipe 16; a first ball nut 3 that has a differential transformer core 19a surrounding the outer periphery thereof; and a control rod drive shaft 9 that drives a control rod vertically by using the first ball nut 3. The external driving system includes: a second ball screw 20 that has an end fixed on an electromagnet 17 and the other end fixed on a differential transformer 19; a drive converter 21 that has a ball nut rotational position detector 23 that detects a rotational position of a second ball nut; an external driving system motor 1b; a rotational position detector 15 that detects a position of a rotor of the external driving system motor 1b; and a rotation transmitter 22 that transmits rotational drive from the external driving system motor 1b to the drive converter 21 by using a universal joint. The external driving system motor 1b is controlled on the basis of difference between an output of the rotational position detector 15 and an output of the ball nut rotational position detector 23.