Abstract: A nozzle seal structure hermetically seals an instrumentation nozzle provided in a manner penetrating a reactor vessel from inside to outside and has a support post inserted therethrough. The instrumentation nozzle includes a flange portion projecting outward in a radial direction orthogonal to a nozzle axis direction at an end portion on an outer side of the reactor vessel.

Abstract: A wind turbine blade pitch angle adjusting apparatus for adjusting the pitch angle of a blade of a wind turbine is provided. The apparatus includes an electric pitch motor able to output a maximum motor torque Tm and a pitch brake assembly able to generate a maximum brake assembly torque Tb. The pitch brake assembly includes a plurality of individual pitch brakes each able to generate a maximum individual brake torque Tsb, the maximum brake assembly torque Tb is the sum of all maximum individual brake torques Tsb, and the maximum motor torque Tm is higher than the maximum individual brake torque Tsb of any one of the pitch brakes.

Abstract: An apparatus for safely controlling a control rod of a nuclear reactor of a nuclear power plant. The apparatus includes a first controller to output a signal to insert or withdraw the control rod. A mechanical portion performs insertion or withdrawal of the control rod in response to the outputted signal. The mechanical portion includes a latch engagement portion, a stop latch to restrain the control rod, a moving latch to move the control rod, and a lift coil to insert or withdraw the control rod. A detector can detect a position or a speed of the control rod. A brake is configured to stop the control rod by force. A second controller operates the brake in response to a brake signal from the detector. The second controller controls the brake independent of the first controller.

Abstract: A control rod drive mechanism (CRDM) configured to latch onto the lifting rod of a control rod assembly and including separate latch engagement and latch holding mechanisms. A CRDM configured to latch onto the lifting rod of a control rod assembly and including a four-bar linkage closing the latch, wherein the four-bar linkage biases the latch closed under force of gravity.

Abstract: A control rod drive mechanism (CRDM) comprises a lead screw, a motor threadedly coupled with the lead screw to linearly drive the lead screw in an insertion direction or an opposite withdrawal direction, a latch assembly secured with the lead screw and configured to (i) latch to a connecting rod and to (ii) unlatch from the connecting rod, the connecting rod being free to move in the insertion direction when unlatched, and a release mechanism configured to selectively unlatch the latch assembly from the connecting rod.

Abstract: A control rod drive mechanism according to the present invention includes a cylindrical guide tube having a latch hole, a hollow piston coupled to the control rod and freely moving up and down within the guide tube, a latch provided in the hollow piston so as to freely swing and freely engaging with and disengaging from the latch hole of the guide tube, and a spring locking the latch to the latch hole of the guide tube. Further, an elevating member having a latch guide which can come into contact with the latch is provided so as to freely move up and down within the guide tube. Further, the latch includes a guide surface coming into contact with the latch guide of the elevating member, and the latch guide includes a guide roller coming into contact with the guide surface of the latch.

Abstract: A securing device for a control rod in a nuclear facility contains a control rod drive and a drive housing enclosing the control rod drive and configured to pass through a reactor pressure wall. The securing device further has a reactor pressure wall connection piece arranged inwardly of the reactor pressure wall and connected to the reactor pressure wall. A device of this type is to be producible as cost-effectively as possible, is to perform its intended tasks reliably and is to be maintenance-free during operation. Accordingly, a number of connection elements are provided for this purpose between the reactor pressure wall connection piece and the drive housing. A respective connection element forms a form-locking connection to the drive housing and a form-locking connection to the reactor pressure wall connection piece.

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 locking piston drive system and valve assembly is provided for shutdown of a nuclear reactor. "Chatter" in a check valve assembly which occurs during charging and/or re-charging of control fluid within a control line is eliminated by providing a valve head and a resisting portion defined on the valve head to resist movement of the valve head when it is urged from sealing engagement on its seat during the charging or re-charging procedure.

Abstract: A nuclear reactor includes a pressure vessel enclosing a plenum, a core in the pressure vessel, a pressure-tight encapsulation in the pressure vessel communicating with the plenum, and control members passing through the encapsulation and having first and second control member segments. The second control member segment has an absorber part to be at least partly inserted into and retracted out of the core for controlling reactivity. The first control member segment has an outer drive part. A control drive is associated with the outer drive part for adjusting the control member along the longitudinal direction thereof. An antieject device for restraining ejection of the control member out of the pressure vessel due to a leak at the encapsulation includes a rod coupling having a disengageable coupling catch interconnecting the first and second control member segments and remaining in engagement during normal control motion of the control member and means for unlocking the coupling catch.

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 radial 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 housing, a rotor disc fixedly connected to the shaft for rotation therewith, and a brake member disposed adjacent to the perimeter of the rotor disc. The rotor disc includes at least one rotor tooth and the brake member includes at least one braking tooth. The brake member is selectively positioned in a deployed position for allowing the braking tooth to contact the rotor tooth for preventing rotation of the shaft in a first direction, and in a retracted position for allowing the rotor disc and shaft to rotate without restraint from the brake member.

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: A rotary lock is disclosed for preventing rotation of a shaft, such as a shaft used in a control rod drive for a nuclear reactor. The lock includes a stationary housing for receiving the shaft, and an arm extending outwardly from the shaft. At least one pin is joined to the housing for circumferential restraint and is positionable in a withdrawn position away from the arm for allowing the arm to rotate with the shaft without obstruction from the pin. The pin is also positionable in a deployed position contacting the arm for preventing rotation of the arm and shaft. Means are provided for selectivity positioning the pin in the withdrawn and deployed positions.

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.

Abstract: A self-latching reactivity-reducing device contains neutron absorbing material and is installable in a guide thimble of a spent fuel assembly for reducing the reactivity of the assembly to allow its storage in an on-site fuel storage facility. The device includes an elongated rod which contains the neutron absorbing material and has a central passage extending between oppposite ends of the rod. A self-latching mechanism is disposed on a leading end of the rod and engageable with a lower end portion of the guide thimble upon full insertion of the rod in the guide thimble so as to render the self-latching mechanism unlatchable from the guide thimble without the use of an independent tool inserted solely through the rod passage from a trailing end thereof. A closure plug is removably fastened to the trailing end of the rod for closing the passage therethrough.

Abstract: In a hydraulic system of a control rod drive for insertion of control rods, a test apparatus and test process is disclosed for determining the integrity of the hydraulic system check valve for preventing inadvertent control rod ejection responsive to the reactor pressure. The check valve is located between a hydraulic valve for causing rod insertion and the hydraulic cylinder. In this interval downstream of the check valve, alteration is made to the hydraulic path by the installation of a conduit with a quick disconnect connected through an isolation valve. Test apparatus for temporary connection at the disconnect is disclosed consisting of a small positive displacement piston and cylinder. The small positive displacement piston and cylinder connects to the quick disconnect through a complementary quick disconnect fitting and a rapidly opening toggle valve. Provision is made for timing the excursion of piston in the piston and cylinder preferably by end of stroke microswitches.

Abstract: The reactor comprises a vessel closed by a lid and containing a core formed of fuel assemblies. The reactor comprises control clusters of two different types and an internal structure fixed inside the vessel, placed above the core and comprising means for guiding the clusters. The mechanisms associated with clusters of a first type each comprise a vertical cylinder belonging to the internal structure of the reactor, defining, with a piston from which is suspended a group of rods belonging to a cluster or forming a cluster, a work chamber. That chamber is connected by a duct, passing through the lid, to a valve for optional connection with a space at a pressure lower than that which prevails in the vessel.

Abstract: The device comprises a vertical shaft (36) movable along its axis under the action of a fluid pressure difference and having means for supporting at least one head (28) of the cluster and a first resilient finger (42) for securing and retaining the head on the support means. It comprises a high position securing mechanism carried by a fixed tube (20) for guiding the cluster and having at least one resilient finger for securing the head and retaining the head against the action of gravity and a vertically movable bolt urged resiliently to a position in which it prevents disengagement of a second resilient finger and cooperating with a mechanism controlling a second cluster so as to be brought into a position in which it releases the second resilient finger when the second cluster passes beyond the highest position assumed during normal operation.

Abstract: Device and method for retaining a linearly movable element in a nuclear reactor. The device comprises, for each shaft, a base fixed to the top part of the reactor internals and coaxial with a shaft guide tube; several grippers or catches spaced apart about the axis of the base and mounted for pivotal movement about a horizontal axis towards a position into and out of engagement with a portion, having circumferential grooves, of the shaft contained in the tube; a slide movable axially on the base towards a top position where it causes engagement of the catches in a groove of the rod, and out of such position; and springs bearing on the base and tending to engage the catches on the shaft. The slide is dimensioned so as to be held by the corresponding sleeve projecting through the reactor vessel cover in a position sufficiently distant from the low position for the catches to be released, whatever the temperature in the reactor.

Abstract: A control device for a PWR includes a plurality of clusters arranged for insertion into and removal from the core and each having a plurality of rods connected to a common carrier vertically slidable in a stationary guide structure and connectable to a drive shaft. First clusters contain neutron absorbing material and are each individually associated with electromagnetic actuation means for adjusting the amount of insertion of the associated one of the first clusters. Second clusters contain a different material and are each individually associated with hydraulic actuation means controllable to cause upward and downward movement. A set of one first cluster and one second cluster is associated with some of said fuel assemblies, with the drive shafts of the two clusters in each set being arranged symmetrically with respect to the axis of a single stationary structure located above the associated fuel assembly and arranged for authorizing mutually independent movement of the first and second clusters.

Abstract: A device for moving a cluster of nuclear reactor control elements, more especially usable for changing the moderation rate of a nuclear reactor, comprising a vertical shaft having nippers cooperating with grabs integral with sub-clusters. Each grab comprises resilient fingers engageable with the nippers and lockable by snap fitting on the fixed upper structure. Each nipper is formed so as to engage resilient fingers and unlock them from the upper structure when the nipper is raised above the position which causes locking of the grab on the structure. A fixed lower structure is provided for causing forced disengagement of the nipper when this latter is lowered beyond the rest position of the grab on this structure. Raising of the nipper then drives the grab by simple bearing force.

Abstract: A method and apparatus for removably attaching a top nozzle to a nuclear fuel assembly to permit easy access to the fuel rods. The quick disconnect top nozzle structure includes guide thimbles which are clearance fitted into an adapter plate of the top nozzle. Load collars are attached to the guide thimbles to support compressive loads such as those imposed by holddown springs. Tensive forces, such as lift forces, are transferred through the top nozzle into peripheral straps of a top spacer grid. The peripheral straps include extensions which resiliently latch onto the top nozzle for ease of assembly and disassembly.

Abstract: Neutron absorber rods are mounted with their upper ends in bores formed in a mounting device and the absorber rods are movable within guide tubes of a nuclear reactor fuel assembly. A holding device is firmly attached to a fixed location of the storage pit. The holding device has holder tubes for absorber rods. In order to replace the absorber rods, the mounting device with the neutron absorber rods is placed and locked in the holding device, the mounting device is disconnected from at least one neutron absorber rod to be replaced, the mounting device with any neutron absorber rods still attached to it is removed from the holding device, the disconnected neutron absorber rods remaining in holder tubes of the holding device are removed for storage, new neutron absorber rods are placed in the empty holder tubes and the mounting device with any neutron absorber rods still connected to it are placed in the holding device and the mounting device is connected to the new neutron absorber rods.

Abstract: A multi-function magnetic jack control drive mechanism for controlling a nuclear reactor is provided. The mechanism includes an elongate pressure housing in which a plurality of closely spaced drive rods are located. Each drive rod is connected to a rod which is insertable in the reactor core. An electromechanical stationary latch device is provided which is actuatable to hold each drive rod stationary with respect to the pressure housing. An electromechanical movable latch device is also provided for each one of the drive rods. Each movable latch device is provided with a base and is actuatable to hold a respective drive rod stationary with respect to the base. An electromechanical lift device is further provided for each base which is actuatable for moving a respective base longitudinally along the pressure housing. In this manner, one or more drive rods can be moved in the pressure housing by sequentially and repetitively operating the electromechanical devices.

Abstract: Anti-ejection device for nuclear reactor control rod.The reactor comprises a tight enclosure integral with the nuclear reactor vessel, the control rod being integral with the command bar. A system for manipulating the command bar comprises means for locking it. These means lock the command bar with respect to the tight enclosure for as long as the force exerted on this bar remains below a limit value. This limit value is at least equal to the force exerted on the command bar in the case of an accidental external cause urging the control rod to leave the reactor core. The device comprises means for obtaining a translation of the control rod, by exerting a force exceeding said limit value on the command bar.

Abstract: The invention relates to an actuating device for two clusters of control rods movable vertically in one and the same fuel array of the core of a nuclear reactor.The first cluster, used for running the reactor, is connected to a first actuating rod (2), the movements of which are effected by a mechanism (27, 28, 29, 30, 34). This rod (2) carries hooking fingers (41), the operation of which is effected by a device (45) mounted slidingly on the end of the rod (2). The device (45) causes the closing of the fingers by means of a spring (46), or on the contrary their opening by overstroke movement towards the top of the rod (2). The second cluster remaining fully inserted into the assembly during a part of the operating cycle of the reactor is connected to a second actuating rod (3).

Abstract: The latching mechanism comprises a pivotable member that cooperates with a contact member for coupling the contact member to the pivotable member. A drive mechanism moves the contact member into contact with the pivotable member thereby pivoting the pivotable member and allowing the contact member to seat in the pivotable member. A biasing mechanism urges the pivotable member into its initial position. The drive mechanism can be also utilized to release the contact member from the pivotable member.

Abstract: A first assembly for low-speed translational displacement and dropping of a control rod comprises a leak-tight casing tube which communicates with the reactor vessel, a screw and nut system coupled to the control rod by means of the nut and a screw-retaining device which is capable of releasing the screw. In the event of accidental failure of the casing tube, upward displacement of the control rod and of the broken portion of the casing tube is limited by a second assembly comprising means for rotational locking of the screw drive rotor and calibrated elastic means for producing action on the rotor in opposition to the vertical thrust produced by failure of the casing tube.