Abstract: The laser welding apparatus includes a welding head and a welding head scanning apparatus. A collimate lens installed on a head body of the welding head is arranged opposite to an end face of optical fibers. The welding head includes only the collimate lens as a lens and the length is shortened. A laser generated by a laser oscillator is introduced into the optical fiber, enters the collimate lens, and then is converted to a parallel beam by the collimate lens. The laser of a parallel beam is irradiated on a surface a welding portion of the welding object through a laser path and the surface of the welding portion is melted. Metallic powder is jetted from powder feed paths formed in a head body to the melted portion and build-up welding is performed on the surface of the welding portion.

Abstract: A shroud support of a BWR includes a shroud support cylinder, shroud support legs welded to a bottom of a reactor pressure vessel (RPV) and a shroud support cylinder, and an annular shroud support plate disposed between the RPV and the shroud support cylinder and welded to the RPV and the shroud support cylinder. A support apparatus is set a CRD housings installed to the bottom of the RPV. A rail guide member horizontally set to the support apparatus reaches directly below the shroud support plate through an opening between the shroud support legs. A bent rail is set on the rail guide member. The bent rail setting a repair device is pushed out along the rail guide member toward the RPV through the opening portion by the rail push-out apparatus set on the support apparatus. The bent rail is spread at directly below the shroud support plate.

Abstract: An underwater remote inspection device is provided with an etching device and a magnifying observation device mounted to a supporting member. A chamber of the etching device is provided with a negative electrode, a positive electrode and a sealing device, and is connected to an etchant supply pipe and an etchant exhaust pipe. A single pair of annular sealing members of the sealing device is provided to a distal end portion of the chamber. A suction passage formed in the side wall of the chamber communicates to a sealing region formed between the sealing members. The magnifying observation device is provided with a magnifying camera in a waterproof container and a plurality of LED lights are installed to the waterproof container. The underwater remote inspection apparatus can prevent leakage of an etchant and reduce execution time of etching.

Abstract: The laser welding apparatus includes a welding head and a welding head scanning apparatus. A collimate lens installed on a head body of the welding head is arranged opposite to an end face of optical fibers. The welding head includes only the collimate lens as a lens and the length is shortened. A laser generated by a laser oscillator is introduced into the optical fiber, enters the collimate lens, and then is converted to a parallel beam by the collimate lens. The laser of a parallel beam is irradiated on a surface a welding portion of the welding object through a laser path and the surface of the welding portion is melted. Metallic powder is jetted from powder feed paths formed in a head body to the melted portion and build-up welding is performed on the surface of the welding portion.

Abstract: In a water jet peening apparatus, a high-pressure under-water pump is installed on an upper end of a casing and an injection nozzle drive mechanism equipped with an injection nozzle is attached to the casing. A high-pressure hose whose one end is connected to the high-pressure under-water pump is disposed in the casing and the other end of the high-pressure hose is connected to the injection nozzle. The casing is seated at an upper end of a control rod drive mechanism housing and the high-pressure under-water pump is driven. The high-pressure water pressurized by the high-pressure under-water pump is supplied to the injection nozzle through the high-pressure hose in the casing and is jetted toward the weld portion between the control rod drive mechanism housing and a stub tube. The time required for a water jet peening operation can be shortened.

Abstract: A access apparatus is set on instrumentation nozzles penetrating a bottom portion of a reactor pressure vessel, in the reactor pressure vessel filling water. The access apparatus has an arm turned, and a mounting fixture that can move along the arm and having a holding member. A cover apparatus having a guide pipe covers the access apparatus, and is installed on the bottom portion in underwater environment in the reactor pressure vessel. The water below the cover apparatus is drained from the reactor pressure vessel to form an air space below the cover apparatus. A variety of device heads is suspended and lowered in the air space through the guide pipe, and mounted to the holding member of the mounting fixture. Repair or preventive maintenance operation against the instrumentation nozzles is performed by the variety of device heads.

Abstract: Even a site having a complicated curved surface shape, such as a welded spot on a bottom of a nuclear reactor core, is simply and electrolytically etched without discharging an etching liquid in a large amount, whereby grain boundary on the surface of the nuclear reactor core internals can be confirmed visually. When the surface of nuclear reactor core internals is electrolytically etched, a sponge provided with holes having a communicating structure is integrated with an etching liquid, and the etching liquid is gelled, while the integrated combination is disposed in front of an electrode, followed by the application of voltage to turn on electricity at a state in which said electrode is electrically connected to the cathode of a direct-current power supply, and brought into contact with or approximated to the surface of the core internals electrically connected to the anode of the direct-current power supply.

Abstract: In an underwater remote surface inspection method for a reactor constituting member, in order to improve the precision of an operation of inspecting a surface shape of the reactor constituting member, an underwater remote surface inspection apparatus includes a replica picking head, an ultrasonic vibrator, and a replica agent cartridge. The replica picking head is pressed against a surface of core internal structure as an inspection target. A replica agent is supplied from the replica agent cartridge into the replica agent supply region formed inside the replica picking head and contacting with the surface of the core internal structure. After the operation of supplying the replica agent ends, an ultrasonic wave is transmitted from an ultrasonic vibrator to the replica agent inside the replica agent supply region. Accordingly, gas bubbles or liquid bubbles existing inside the replica agent supply region rise up so as to be discharged to the outside of the replica picking head through an air extracting hole.

Abstract: In view of the above-mentioned problems, an object of the present invention is to provide a processing method that is not dependent on the material or the ion beam irradiation angle. In order to achieve the object above, the present invention provides a processing device that processes a sample by irradiating the sample with an ion beam, the processing device comprising a sample tilting/rotating mechanism that rotates/tilts the sample relative to the ion beam, wherein the sample rotating mechanism comprises a rotating shaft that rotates the sample relative to the ion beam, and a tilting shaft that is orthogonal to the rotating shaft and that tilts the sample relative to the ion beam, the sample rotating mechanism being adapted to simultaneously perform the rotating and tilting of the sample.

Abstract: Even a site having a complicated curved surface shape, such as a welded spot on a bottom of a nuclear reactor core, is simply and electrolytically etched without discharging an etching liquid in a large amount, whereby grain boundary on the surface of the nuclear reactor core internals can be confirmed visually. When the surface of nuclear reactor core internals is electrolytically etched, a sponge provided with holes having a communicating structure is integrated with an etching liquid, and the etching liquid is gelled, while the integrated combination is disposed in front of an electrode, followed by the application of voltage to turn on electricity at a state in which said electrode is electrically connected to the cathode of a direct-current power supply, and brought into contact with or approximated to the surface of the core internals electrically connected to the anode of the direct-current power supply.

Abstract: An underwater remote inspection device is provided with an etching device and a magnifying observation device mounted to a supporting member. A chamber of the etching device is provided with a negative electrode, a positive electrode and a sealing device, and is connected to an etchant supply pipe and an etchant exhaust pipe. A single pair of annular sealing members of the sealing device is provided to a distal end portion of the chamber. A suction passage formed in the side wall of the chamber communicates to a sealing region formed between the sealing members. The magnifying observation device is provided with a magnifying camera in a waterproof container and a plurality of LED lights are installed to the waterproof container. The underwater remote inspection apparatus can prevent leakage of an etchant and reduce execution time of etching.

Abstract: A access apparatus is set on instrumentation nozzles penetrating a bottom portion of a reactor pressure vessel, in the reactor pressure vessel filling water. The access apparatus has an arm turned, and a mounting fixture that can move along the arm and having a holding member. A cover apparatus having a guide pipe covers the access apparatus, and is installed on the bottom portion in underwater environment in the reactor pressure vessel. The water below the cover apparatus is drained from the reactor pressure vessel to form an air space below the cover apparatus. A variety of device heads is suspended and lowered in the air space through the guide pipe, and mounted to the holding member of the mounting fixture. Repair or preventive maintenance operation against the instrumentation nozzles is performed by the variety of device heads.

Abstract: In an underwater remote surface inspection method for a reactor constituting member, in order to improve the precision of an operation of inspecting a surface shape of the reactor constituting member, an underwater remote surface inspection apparatus includes a replica picking head, an ultrasonic vibrator, and a replica agent cartridge. The replica picking head is pressed against a surface of core internal structure as an inspection target. A replica agent is supplied from the replica agent cartridge into the replica agent supply region formed inside the replica picking head and contacting with the surface of the core internal structure. After the operation of supplying the replica agent ends, an ultrasonic wave is transmitted from an ultrasonic vibrator to the replica agent inside the replica agent supply region. Accordingly, gas bubbles or liquid bubbles existing inside the replica agent supply region rise up so as to be discharged to the outside of the replica picking head through an air extracting hole.

Abstract: A method of performing maintenance on a structural member inside a reactor pressure vessel includes lowering an annular guide rail having a second lug until the guide rail rests on an upper flange of a core shroud provided inside the reactor pressure vessel, detachably mounting the second lug of the guide rail to a first lug mounted on the core shroud, positioning a discharging nozzle at a position at which compressive remaining stress is added to a surface of the core shroud by moving the discharging nozzle in a radial direction and an axial direction of the core shroud by a discharging nozzle moving apparatus mounted on a turnable revolving on the guide rail and discharging water to add compressive remaining stress to a surface of the core shroud from the discharging nozzle.

Abstract: A preventive maintenance apparatus for structural members inside a nuclear reactor pressure vessel includes a ring-shaped guide rail having a plurality of lugs which is placed on an upper flange of a core shroud provided inside a reactor pressure vessel. At least some of lugs separately engage with a plurality of guide rods provided on an inner surface of the reactor pressure vessel. A turntable is rotated on the guide rail. A first discharging nozzle moving apparatus placed on the turntable moves a first discharging nozzle for adding compressive remaining stress to an outer surface of the core shroud in a radial direction of the core shroud and in an axial direction of the core shroud. A second discharging nozzle moving apparatus placed on the turntable moves a second discharging nozzle for adding compressive remaining stress to an inner surface of the core shroud in a radial direction of the core shroud and in an axial direction of the core shroud.

Abstract: An apparatus preventive maintenance having a driving mechanism capable of driving a jet nozzle 24 to cause it to travel upward-and-downward, to rotate and to swing is settled on the top of a housing in the bottom portion of a reactor pressure vessel and on a hole for a fuel support piece, water pumped by a high pressure pump is spouted from a jet nozzle, and cavitation bubbles generated during the spouting are supplied to the positions to be treated for preventive maintenance, such as housings in the bottom portion of the reactor pressure vessel. Therewith, the residual tensile stress in the position to be treated is improved in a releasing direction by the energy generated by the collapsing of the cavitation bubbles.

Abstract: Low temperature water in a low temperature water tank 12 installed outside a reactor pressure vessel 9 is pumped by a high pressure pump 15 and supplied through a conductor 17 under pressure. The supplied water is ejected, as a stream of cold water jet 8, from a nozzle 14 connected to the conductor 17 and introduced into the reactor pressure vessel 9 by a driving mechanism. The stream of cold water jet 8 ejected from the nozzle 14 is directed to impinge against a predetermined position of a core shroud 13 in reactor water 11 filled in the reactor pressure vessel 9 and being at temperature higher than the low temperature water. Then, while continuing to eject the cold water jet 8 from the nozzle 14, the nozzle 14 is moved away from the predetermined position, or the ejection of the cold water jet 8 from the nozzle 14 is stopped, allowing the predetermined position to be heated again with the temperature of the reactor water 11.

Abstract: By applying spot welding along a crack which has occurred in an austenitic stainless steel structure without use of welding material so that spot welds are connected, melting and solidifying of the crack can be achieved, thereby to provide a metal structure which is rich with delta ferrite of the austenitic stainless steel structure or prevent propagation of the crack by enclosing it into the interior of the austenitic stainless steel structure.

Abstract: A method of maintaining the housing of a reactor pressure vessel having: a reactor pressure vessel into which cooling water is introduced; a cylindrical housing which penetrates an end bracket of the reactor pressure vessel; and a circumferential weld for securing the intermediate portion of the housing to the reactor pressure vessel by welding, the method of maintaining a housing of a reactor pressure vessel comprising the steps of: remaining the cooling water in the reactor pressure vessel; preventing leakage of the cooling water in the reactor pressure vessel through the housing by sealing the housing; making the inside portion of the housing lower than the seal to be a hollow space of a gas atmosphere; heating a heat affected zone due to welding by using a heating device inserted into the hollow space from a lower portion so as to compressive-yield the inner surface of the housing in the heat affected portion upper than the circumferential weld and tensile-yield the outer surface; and cooling heated porti

Abstract: A water jet peening method in which a pressurized water jet flow containing cavities is jetted through a nozzle having a velocity increasing orifice portion and a horn-like jetting hole formed continuously with the velocity increasing orifice portion to impinge against a surface of a metallic material immersed in water and to cause the cavities to collapse at the surface of the metallic member, and a tensile plastic deformation is caused in a surface layer of the metallic material by a local high pressure generated by the impingement and the collapse so that a residual tensile stress in the surface of the metallic member is reduced. In this method, the nozzle is vibrated so that vibration-induced cavities are formed in the vicinity of a nozzle wall surface, and the vibration-induced cavities are caused to impinge against the surface of the metallic member by the pressurized water jet flow containing cavities.