RETARDATIONSANORDNING FOR FORDROJNING AV EN STYRSTAVSUTDRIVNING VID EN STYRMANOVERANORDNING HOS EN KERNREAKTOR

摘要

A control rod ejection retardation assembly is mounted to a control rod assembly of a nuclear reactor to retard the ejection of the control rod only during an undesired ejection of the control rod while allowing normal control rod movement and "scramming" operation to be drag free and unretarded. The ejection retardation assembly includes a piston assembly mounted to the control rod and having an opening thereto controlled by a ball valve. The piston assembly seals are made loose fitting to allow sufficient fluid flow through the seals to provide unhindered normal control rod movement even with the ball valve sealing the piston assembly opening. During undesired speedy ejection of the control rod, the ball valve seals the opening to prevent fluid flow to the piston assembly retarding piston movement and thereby controlling control rod movement. During a "scram" condition the ball valve unseals the piston opening allowing fluid to easily flow into the piston assembly to prevent any retardation of piston and control rod movement.