HYDRAULIC CONTROL ROD DRIVE UNIT AND DRIVE SYSTEM

摘要

PROBLEM TO BE SOLVED: To provide a hydraulic control rod drive unit and drive system capable of inserting a control rod to a reactor core at a high speed in the emergency stop of the reactor without being substantially accompanied by a rise of equipment cost. SOLUTION: This hydraulic control rod drive system for high-speed insertion of control rod is provided with a cylinder 28 equipped with drive water inlet 22 and outlet 34 for driving a control rod assembly 21; a control rod drive shaft 23 connected to the control rod; diameter-extended attraction parts 24 and 25 fixed to the drive shaft; a floating piston 26 larger in diameter than the diameter extended attraction parts but smaller than the inside diameter of the cylinder; and an electromagnet 29 arranged in the upper part of the cylinder, which attracts the diameter extended attraction parts when the control rod is in an upper limit position to hold the control rod in the upper limit position. When drive water is stopped after attraction by the diameter extended attraction parts, the floating piston 26 is preliminarily lowered to its lower limit position, and when the electromagnet is demagnetized in the stop of the reactor, the control rod is lowered to the lower limit position at a high speed.