Control rod for nuclear reactor

Claim 1

IN A NUCLEAR REACTOR INCLUDING A VERTICALLY EXTENDING PRESSURE VESSEL, A CONTROL ROD ASSEMBLY COMPRISING A TUBULAR GUIDE SL.EEVE MOUNTED IN THE LOWER PORTION OF SAID REACTOR VESSEL IN AN UPWARDLY EXTENDING POSITION AND IN A MANNER AFFORDING LIMITED ANGULAR MOVEMENT OF SAID SLEEVE ABOUT ITS LOWER END, A CONTROL ROD DISPOSED IN SAID GUIDE SLEEVE AND COMPRISING A PLURALITY OF ELONGATED NETURON ABSORBING SECTIONS INTERCONNECTED IN A MANNER AFFORDING ANGULAR MOVEMENT THEREBETWEEN, A PUSH ROD RELEASABLY CONNECTED TO THE LOWER END OF SAID CONTROL ROD AND EXTENDING DOWNWARDLY FROM SAID VESSEL IN GENERALLY AXIALLY EXTENDING RELATION TO SAID GUIDE SLEEVE, CONTROL ROD DRIVE MEANS CONNECTED TO THE LOWER END OF SAID PUSH ROD, SAID DRIVE MEANS COMPRISING A ROTATABLE DRIVE SHAFT, A REVERSIBLE HYDRAULIC MOTOR CONNECTED WITH ONE END OF SAID DRIVE SHAFT, A SCREW DRIVE MEANS INTERCONNECTING THE OTHER END OF SAID DRIVE SHAFT WITH SAID PUSH ROD IN A MANNER AFFORDING AXIAL MOVEMENT OF THE LATTER IN RESPONSE TO ROTARY MOVEMENT OF THE FORMER, A SOURCE OF PRESSURE FLUID, PASSAGE MEANS CONNECTING SAID SOURCE WITH SAID MOTOR, A FIRST CONTROL VALVE DISPOSED IN CONTROLLING RELATION TO SAID PASSAGE MEANS AND OPERABLE TO DIRECT THE PRESSURE FLUID SO AS TO AFFORD SELECTIVE ROTATION OF SAID MOTOR IN EITHER DIRECTION AT A PREDETERMINED FIRST SPEED, A PRESSURE FLUID ACCUMULATING CHAMBER IN FLUID COMMUNICATION WITH SAID PASSAGE MEANS, AND A SECOND CONTROL VALVE DISPOXED IN CONTROLLING RELATION TO THE DISCHARGE SIDE OF SAID ACCUMULATING CHAMBER AND OPERABLE TO REALEASE PRESSURE FLUID FROM SAID CAHMBER INTO SAID PASSAGE MEANS, TO THEREBY OPERATE SAID MOTOR AND EFFECT UPWARD MOVEMENT OF SAID CONTROL ROD AT A SPEED CONSIDERABLY GREATER THAN SAID FIRST SPEED.