Abstract: A control rod drive system for a nuclear reactor that employs hydraulic cylinders to operate a conventional plunger/gripper drive system to incrementally move control rods into and out of the core of a reactor. The pressure differential for driving hydraulic pistons within the cylinders is obtained from the difference in pressure between the outside and inside of the core barrel of the reactor and control of the pistons is obtained from external solenoids attached to the reactor control system. The external solenoids regulate a charging pump feed to Poppet valves that control the hydraulic feed to the cylinders. A hydraulic piston/cylinder drive is also provided for the shutdown rods which operate in either an all in or out of the core condition.

Abstract: An automatically scramming nuclear reactor system. One embodiment comprises a core having a coolant inlet end and a coolant outlet end. A cooling system operatively associated with the core provides coolant to the coolant inlet end and removes heated coolant from the coolant outlet end, thus maintaining a pressure differential therebetween during a normal operating condition of the nuclear reactor system. A guide tube is positioned within the core with a first end of the guide tube in fluid communication with the coolant inlet end of the core, and a second end of the guide tube in fluid communication with the coolant outlet end of the core. A control element is positioned within the guide tube and is movable therein between upper and lower positions, and automatically falls under the action of gravity to the lower position when the pressure differential drops below a safe pressure differential.

Abstract: In a boiling water reactor controlling each control rod hydraulically by driving a solenoid valve, the control system comprises an operation control means 41 having a duplicated data processing unit for generating sequence patterns based on the timing of the driving sequence based on the control information provided manually, a transmission control means 42 for creating a command word corresponding to each control rod being controlled based on said sequence pattern, and mutually communicating each command word between duplicated data processing units and computing the AND logic of said data within a predetermined time difference, and when the computed result coincide, transmitting the selected command word serially; a transmission unit 32 for receiving said command word and performing protocol conversion thereto, and transmitting the same to a plurality of transmission branch units positioned downstream as the control command; and a solenoid valve drive circuit 31 for driving the control rod drive unit corres

Abstract: A control rod driving apparatus adapted to drive a control rod assembly for a nuclear reactor is disposed in a housing mounted to a reactor pressure vessel of the nuclear reactor and includes a guide tube disposed in the housing, a connection pipe disposed inside the guide tube coaxially therewith and having one end to which a control rod assembly is connected, a ball spindle disposed inside the connection pipe and supported thereby so as to be rotatable by a ball nut assembly engaged with the ball spindle so as to be axially movable along the ball spindle, the ball nut assembly supporting another end of the connection pipe, a hydraulic drive operatively connected to the ball spindle to rotate the ball spindle, and a transmission mechanism operatively connected to the drive for transmitting a power of the drive to the ball spindle.

Abstract: A fast-acting nuclear reactor control device for moving and positioning a fety control rod to desired positions within the core of the reactor between a run position in which the safety control rod is outside the reactor core, and a shutdown position in which the rod is fully inserted in the reactor core. The device employs a hydraulic pump/motor, an electric gear motor, and solenoid valve to drive the safety control rod into the reactor core through the entire stroke of the safety control rod. An overrunning clutch allows the safety control rod to freely travel toward a safe position in the event of a partial drive system failure.

Abstract: A drive for positioning a control rod in a nuclear reactor core is disclosed. The drive includes a turbine rotor joined to a hollow spindle in a housing. The spindle has a piston disposed therein and a piston rod extending therefrom and through a bottom end of the spindle for being joined to the control rod. A pressurized fluid is provided into the spindle for exerting a pressure force against the piston for moving the piston for selectively gripping the control rod. Interruption of the pressurized fluid to the spindle causes ungripping of the control rod.

Abstract: A high speed air cylinder in which the longitudinal movement of the piston within the air cylinder tube is controlled by pressurizing the air cylinder tube on the accelerating side of the piston and releasing pressure at a controlled rate on the decelerating side of the piston. The invention also includes a method for determining the pressure required on both the accelerating and decelerating sides of the piston to move the piston with a given load through a predetermined distance at the desired velocity, bringing the piston to rest safely without piston bounce at the end of its complete stroke.

Abstract: A hydraulic lock for latching a displacer rod drive mechanism in an up position. A piston having a truncated cone-shaped valve element is formed at an end of the drive rod. A complementary truncated cone-shaped valve seat is formed in the cap of the reactor housing. When the drive rod is activated to the up position, the valve element seats against the valve seat creating a seal and a pressure boundary. The piston is provided with piston rings. The pressure differential acting across the piston is transferred to the area of contact between the valve element and valve seat thus maintaining the drive rod in the up position and preventing leakage flow from around the piston rings. A hydraulic control system for operating the hydraulic latch is also disclosed.