Control rod actuator mechanism

Claim 1

AN ACTUATOR MECHANISM FOR A PRESSURIZED FLUID NUCLEAR REACTOR COMPRISING A HOUSING SECURED TO THE TOP EXTERIOR OF THE PRESSURE VESSEL OF A PRESSURIZED FLUID NUCLEAR REACTOR WITH THE INTERIOR OF SAID HOUSING COMMUNICATING WITH THE INTERIOR OF SAID PRESSURE VESSEL, A PISTON MEMBER MOVABLE RECIPROCALLY IN SAID HOUSING IN A VERTICAL DIRECTION AND DIMENSIONED TO PROVIDE LIMITED CLEARANCE BETWEEN ITS PERIPHERY AND SAID HOUSING FOR PASSAGE OF FLUID A VAND MEMBER FIXED IN SAID HOUSING ABOVE SAID PISTON MEMBER AND ROTATABLE ABOUT A VERTICAL AXIS IN A DIRECTION DETERMINED BY THE DIRECTION OF FLUID FLOW THROUGH ITS VANCES, AND ELONGATED VERTICAL MEMBER THREADEDLY ENGAGED BY SAID VANED MEMBER AND SECURED TO SAID PISTON MEMBER, SAID ELONGATED MEMBER BEING REMOVABLE VERTICALLY ON ROTATION OF SAID VANED MEMBER, A CONTROL ROD COUPLED TO SAID PISTON MEMBER FOR MOVEMENT IN SAID PRESSURE VESSEL CORRESPONDING TO THE MOVEMENT OF SAID ELONGATED MEMBER, FIRST AND SECOND CONDUIT MEANS CONNECTED TO SAID HOUSING ABOVE SAID VENED MEMBER AND BELOW SAID VANED MEMBER, RESPECTIVELY, FOR CIRCULATING FLUID THROUGH SAID VANED MEMBER TO EFFECT ROTATION THEREOF.