Abstract: This disclosure enables a creation of a detachable connection between a linear motor tubular armature and a vertical cylindrical rod of an actuator of a control and protection system of a nuclear reactor. Such configuration reduces a dose load on a member of personnel, as well as provides an increase in reliability of a coupling of the linear motor tubular armature and the vertical cylindrical rod in conditions of high temperature and radiation.

Abstract: A control rod drive contains a drive housing, in which a control rod carrying element is moveable between a basic position and an end position. The control rod carrying element is guided over a portion in a throttle bush. Formed across the throttle bush is a free flow cross section for a pressure fluid which varies in dependence on a position of the control rod carrying element. During an emergency shutdown, in which the control rod carrying element is moved hydraulically via a pressure fluid, the flow resistance for the pressure fluid is reduced, when the control rod carrying element reaches the end position. Therefore, a braking of the control rod carrying element takes place before it reaches the end position, thus reducing mechanical loads during braking. A flow resistance change takes place via a variable outside diameter of the control rod carrying element and/or by a bypass orifice.

Abstract: A control rod drive mechanism includes a first tubular member having a first threaded portion and a first generally cylindrical outer surface, the first tubular member including a first plurality of slots spaced circumferentially on the first outer surface and extending in a direction parallel to the axis of the first tubular member, and a second tubular member having a second threaded portion and a second generally cylindrical outer surface, the second tubular member including a second plurality of slots spaced circumferentially on the second outer surface and extending in a direction parallel to the axis of the second tubular member. The first and second tubular members are axial aligned with the first and second threaded portions being engaged with each other to form a threaded joint therebetween. A locking sleeve overlaps at least a portion of the first outer surface of the first tubular member and at least a portion of the second outer surface of the second tubular member.

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 control rod drive having a magnetic coupling device which eliminates the need for packing-type seal assemblies for preventing leakage from the reactor pressure vessel adjacent the spindle. The magnetic coupling device includes a driving rotor and a driven rotor separated by a pressure barrier which forms part of the reactor pressure boundary. The driven rotor and the driving rotor are coupled magnetically so that the driven rotor rotates in response to rotation of said driving rotor, whereby the control rod displaces in response to operation of the drive motor. The driven and driving rotors are each constructed by stacking a plurality of circular magnetic rings concentric with a centerline axis. Each circular ring has multiple poles circumferentially distributed thereon. An anti-rotation device is incorporated to prevent free rotation of the spindle when the drive motor is removed during maintenance operations. The anti-rotation device includes a push rod actuator which penetrates the pressure barrier.

Abstract: A boiling water reactor includes a pressure vessel containing a reactor core, chimney, steam separator assembly, and steam dryer assembly therein, with the vessel being filled with reactor water to a normal water level through the steam separator assembly. A plurality of control rod drives extend downwardly from the bottom of the pressure vessel and are operatively joined to control rods extending downwardly into the reactor core. The chimney includes a plurality of channels disposed above the core and laterally spaced apart to define guide slots for receiving the control rods as they are selectively translated upwardly out of the core by the control rod drives. The chimney has a vertical height for increasing the normal water level above the reactor core and for providing a space for the control rods withdrawn from the reactor core by the bottom-mounted control rod drives.

Abstract: A boiling water reactor includes a pressure vessel containing a reactor core, chimney, steam separator assembly, and steam dryer assembly therein, with the vessel being filled with reactor water to a normal water level through the steam separator assembly. A plurality of control rod drives extend downwardly from the bottom of the pressure vessel and are operatively joined to control rods extending downwardly into the reactor core. The chimney includes a plurality of channels disposed above the core and laterally spaced apart to define guide slots for receiving the control rods as they are selectively translated upwardly out of the core by the control rod drives. The chimney has a vertical height for increasing the normal water level above the reactor core and for providing a space for the control rods withdrawn from the reactor core by the bottom-mounted control rod drives.

Abstract: A segmented electromagnetic coil assembly for use in a magnetic jack type of drive mechanism used to move control rods within a nuclear reactor. The coil assembly has a plurality of individual magnetic coils spaced around and against the non-magnetic housing which contains the control rod drive shaft.

Abstract: A brake assembly is disclosed for selectively preventing rotation of a shaft, such as a shaft used in a control rod drive for a nuclear reactor. The brake assembly includes a stationary base, a rotor disc fixedly connected to the shaft for rotation therewith, and a brake member disposed adjacent to the rotor disc. The rotor disc includes at least one rotor tooth and the brake member includes at least one braking tooth. The member is selectively positionable in a deployed position for allowing the braking tooth to contact the rotor tooth for preventing rotation of the shaft in a first direction while permitting roation in the opposite direction, and in a retracted position for allowing the rotor disc and shaft to rotate in either direction without restraint from the brake member.

Abstract: A drive for moving a control rod in a pressure vessel containing a pressurized fluid includes a spindle disposed solely within the pressure vessel, which spindle is effective for moving the control rod upon rotation thereof. A driven rotor is fixedly joined to the spindle within the pressure vessel for rotating the spindle, and the driven rotor is selectively rotated in first and second opposite directions without the need for packing-type seal assemblies for preventing leakage of the pressurized fluid from the pressure vessel adjacent to the spindle.

Abstract: A latch assembly is disclosed for selectively preventing rotation of a shaft, such as a shaft used in a control rod drive for a nuclear reactor. The latch assembly includes a stationary housing for receiving the shaft, and a gear fixedly joined to the shaft. A latch arm is pivotally joined to the housing and includes at least one latch tooth facing gear teeth extending from the gear. The latch arm is selectively positionable in an engaged position to abut the latch tooth against a first one of the gear teeth for preventing rotation of the shaft in a first direction, and in a disengaged position to space the latch tooth away from the gear teeth for allowing the shaft to rotate without obstruction between the gear teeth and the latch tooth.

Abstract: A lock assembly is disclosed for selectively preventing rotation of a shaft, such as a shaft used in a control rod drive for a nuclear reactor. The lock assembly includes a stationary housing for receiving the shaft, and a gear fixedly joined to the shaft. The gear includes a plurality of circumferentially spaced gear teeth. An elongate key is slidably joined to the housing and has at least one locking tooth facing the gear teeth. The key is selectively positionable in an engaged position wherein the locking tooth and gear teeth prevent rotation of the shaft in a first direction, and in a disengaged position for allowing the shaft to rotate without obstruction between the gear teeth and the locking tooth.

Abstract: So as to position a device, such as an eddy current probe support inside a cylindrical cavity with radial perforations opening into said cavity, a device (36) is proposed, said device including a pole (50) orientated parallel to the axis of the cavity. This pole may occupy different pre-established indexing positions in rotation and in translation inside the cavity by means of a mechanism (42, 44, 54, 58, 60). In each of these indexing positions, an active head (98), mounted at the extremity of the pole (50) by means of a pantograph (66) and a cladding arm (100), is able to move in a specific active zone on the lower wall of the cavity. To this effect, the active head is clad by the arm (100) and is equipped with autonomous thrustors controlling its movement.

Abstract: A latch and linkage arrangement in a nuclear reactor control rod drive mechanism includes a latch having an elongated body with opposite ends and opposite side edges and multiple latch teeth defined along one of body side edges between the opposite ends. The arrangement also includes a plurality of links. A first link pivotally connects with the latch body adjacent one end and is pivotally connected to an electromagnetic armature for applying a motive force to the latch body through the first link. Second and third links are pivotally connected to the latch body and to a support tube in parallel relationship to one another so as to define a parallelogram therewith such that when the motive force is applied to the body via the first link the latch body and thereby the latch teeth undergo curvilinear movement toward and away from a latching position.

Abstract: A coupling device is disclosed which is in rotation between a motor member and a receiver member. The device has a ratchet ring, a pawl holder ring and a drive ring. The pawl holder ring has stops and pawls with a shoulder and a stop surface and pivots between an engaged position and a disengaged position. The drive ring has drivers engaged in the stops. A contoured cam on the drive ring bears on the pawl shoulder in order to pivot it towards its engaged position. Elastic biasing means are positioned between the driver and one of the stops. The coupling device is adapted for use in the control of control rods in a nuclear reactor.

Abstract: A safety device to be applied to the vertical displacement of, for example, the control rods of a nuclear reactor, comprises the combination of a stator placed on the outside upper part of an impervious, nonmagnetic cylinder within the inside of which a rotor is mounted about its shaft, free in axial translation, with the shaft rotatable with the rotor but fixed in translation, and with the rotation of the shaft transferred to a hollow threaded rod which will transfer rotation to a nut slidable vertically inside the cylinder, supporting the control rods therebelow; the rotor also controlling the opening and closing of a jaw for holding and releasing the hollow threaded rod.

Abstract: A control rod drive uses gravitational forces to insert one or more control rods upwardly into a reactor core from beneath the reactor core under emergency conditions. The preferred control rod drive includes a vertically movable weight and a mechanism operatively associating the weight with the control rod so that downward movement of the weight is translated into upward movement of the control rod. The preferred control rod drive further includes an electric motor for driving the control rods under normal conditions, an electrically actuated clutch which automatically disengages the motor during a power failure and a decelerator for bringing the control rod to a controlled stop when it is inserted under emergency conditions into a reactor core.

Abstract: A fine-motion control rod drive for a nuclear reactor, which can be disassembled in sections. The drive includes a spindle defining a sealing surface to prevent spillage after the drive motor is removed. A spline connection with a sliding key arrangement permits the shaft of the drive motor to be separated from the spindle during disassembly. The drive motor is effective for uncoupling the control rod drive piston from the control rod prior to disassembly.

Abstract: A linear motion device, more specifically a control rod drive mechanism (CRDM) for inserting and withdrawing control rods into a reactor core, is capable of independently and sequentially positioning two sets of control rods with a single motor stator and rotor. The CRDM disclosed can control more than one control rod lead screw without incurring a substantial increase in the size of the mechanism.

Abstract: Reactivity control assembly for nuclear reactor comprises supports stacked above reactor core for holding control rods. Couplers associated with the supports and a vertically movable drive shaft have lugs at their lower ends for engagement with the supports.

Abstract: A rack and pinion mechanism for vertical up-and-down movement of neutron-absorbing control elements to control the power and to shut down a nuclear reactor in case of emergency. The upper portions of the elements constitute the rack, engaging a rotatably driven pinion perpendicular thereto and having teeth on a lateral face engaging corresponding teeth of a clutch pinion. The rack and pinion remain on continuous enagement, while the clutch pinion selectively engages and disenages the pinion, the translatory axial movement of the clutch pinion being controlled by a vertically moving actuating member controllable from the upper part of the apparatus.

Abstract: A nuclear reactor, control rod holding latch permits rapid insertion of the control rod into a reactor core by a ratchet and pawl mechanism arranged to lock the control rod against withdrawal, this being done through a screw which by rotation permits slow withdrawal of the control rod from the core, while keeping the control rod locked against withdrawal other than through the screw action.