Abstract: An eddy current flaw detection system includes an eddy current flaw detection probe having a substrate facing an inspection surface, and at least one exciting coil and at least two detecting coils provided on the substrate, a scanning device which scans the probe on the inspection surface, a scan control device which drives and controls the scanning device, an eddy current flaw detection device which acquires results of detection of a plurality of detection points corresponding to combinations of the exciting and detecting coils for each scan position of the probe, and a data processing/display device which processes data from the scan control device and the eddy current flaw detection device and thereby displays a result of flaw detection. The data processing/display device acquires three-dimensional coordinates of the detection points for each scan position of the probe and thereby creates three-dimensional flaw detection data.

Abstract: An ultrasonic reactor water level measuring device and an evaluation method are provided and prevent a reduction in the measurement accuracy of a water level that is in a wide measurement range. The ultrasonic reactor water level measuring device includes an upper tube extending from a gas phase portion in a reactor, a lower tube extending from a liquid phase portion in the reactor, measurement tubes connected to each other and arranged at multiple stages between the upper tube and the lower tube, and units for generating and receiving ultrasonic waves, the units being arranged at bottom portions of the measurement tubes. The ultrasonic reactor water level measuring device measures levels of water within the measurement tubes and calculates a water level within the reactor from the sum of the measured water levels, the sum excluding an overlapped part of the measurement tubes.

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: A top head of a reactor pressure vessel includes control rod drive mechanism (CRDM) penetration pipes arranged in a square grid-like pattern. The CRDM penetration pipes are joined with one another by a tube support member. The top head is placed on a tank and water is filled in an inner region of the tank and the top head. A travel apparatus moves a nozzle lifting and lowering apparatus to a predetermined location. A lifting and lowering mechanism of the nozzle lifting and lowering apparatus lifts a jet nozzle above the tube support member among the neighboring four CRDM penetration pipes. An ejection outlet of the jet nozzle is directed to a weld between one of the CRDM penetration pipes and the top head, and a water jet is ejected. A nozzle turning mechanism turns the jet nozzle, and WJP is executed sequentially to the four CRDM penetration pipes.

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: An ultrasonic inspection method and an ultrasonic inspection device allow three-dimensional inspection data and three-dimensional shape data to be appropriately positioned on a display screen and allow a defect echo and a shape echo to be quickly identified even when information on the relative positions of a probe and an object to be inspected is not provided. The ultrasonic inspection data that is generated from the waveforms of ultrasonic waves received by an ultrasonic probe is compared with a plurality of ultrasonic propagation data pieces calculated by a ray tracing method on the basis of the three-dimensional shape data on an object to be inspected. The position of the three-dimensional inspection data or the three-dimensional shape data is moved relative to the other data position on the basis of the comparison results, thereby displaying the three-dimensional inspection data and the three-dimensional shape data while overlapping each other.

Abstract: An adsorbing substance made of a material having an acid center in its molecular frame is installed in a passage for steam generated in a reactor pressure vessel 1. The adsorbing substance adsorbs and holds N-16 compound for decay. Therefore, the amount of N-16 entering into a turbine system is decreased and dose in the turbine system can be reduced.

Abstract: A core of a light water reactor has a plurality of fuel assemblies. The fuel assemblies include a plurality of fuel rods in which a lower end is supported by a lower tie-plate and an upper end is supported by an upper tie-plate. The fuel rods form plenums above a nuclear fuel material zone and have a neutron absorbing material filling zone under the nuclear fuel material zone. Neutron absorbing members attached to the upper tie-plate are disposed between mutual plenums of the neighboring fuel rods above the nuclear fuel material zone. The neutron absorbing members have a length of 500 mm and are positioned at a distance of 300 mm from the nuclear fuel material zone. Even if the overall core is assumed to become a state of 100% void, no positive reactivity is inserted to the core.

Abstract: A method for improving a residual stress in a pipe includes improving the residual stress in the inner surface to the compressive direction by rapid cooling of the inner surface after heating of the pipe. The heating is to heat a vicinity of a welded part of the pipe from the outer surface to raise the temperature to a construction temperature. The rapid cooling is to rapidly cool the inner surface in the vicinity of the welded part by supplying cooling water into the pipe. The heating and the rapid cooling are repeated twice or more. A method for construction management includes determining whether construction has been executed properly based on a maximum value of a lowering rate of an outer surface temperature of the pipe when the cooling water is supplied for the rapid cooling of the inner surface and a thickness of the pipe in a measuring position of the outer surface temperature.

Abstract: Vibration of a jet pump installed in a reactor pressure vessel of a boiling water reactor is monitored. Ultrasonic waves are transmitted from an ultrasonic sensor installed on an outer surface of the reactor pressure vessel toward a throat and a diffuser of the jet pump. When the ultrasonic waves reach respective outer surfaces of the throat and diffuser, reflected waves are generated at the respective outer surfaces. The ultrasonic sensor receives those reflected waves. The ultrasonic signal process section obtains a distance in the horizontal direction between the throat and the diffuser based on a time difference of the reflected waves reflected from respective reflection surfaces of the throat and diffuser and a sound speed in reactor water in the neighborhood of the throat and diffuser. A relative vibration is obtained based on the change with time of the distance.

Abstract: A chamber having a water jet generation apparatus and a mesh installed inside is pushed against a surface of a peening object. A rotary vane of the water jet generation apparatus, disposed in a region in the chamber between the mesh and the chamber, is rotated to generate a water jet flowing toward the peening object in one region in the chamber, the one region is a region closer to the peening object than the mesh. A plurality of shots 4 put in the region 30A moves toward the peening object along with the water jet and collides with the surface of the peening object. After the collision, the shots move toward the mesh along with the water jet. Compression residual stress is given to the surface of the peening object with which the shots have collided. Thus, spreading of contaminants peeled off from a peening object can be prevented.

Abstract: A core of a light water reactor has a plurality of fuel assemblies. The fuel assemblies include a plurality of fuel rods in which a lower end is supported by a lower tie-plate and an upper end is supported by an upper tie-plate. The fuel rods form plenums above a nuclear fuel material zone and have a neutron absorbing material filling zone under the nuclear fuel material zone. Neutron absorbing members attached to the upper tie-plate are disposed between mutual plenums of the neighboring fuel rods above the nuclear fuel material zone. The neutron absorbing members have a length of 500 mm and are positioned at a distance of 300 mm from the nuclear fuel material zone. Even if the overall core is assumed to become a state of 100% void, no positive reactivity is inserted to the core.

Abstract: A jet pump beam (hereinafter, referred to as a beam) is fitted into a pair of projecting portions installed to a transition piece, and after the beam is arched, a beam bolt engaged with the beam is tightened. An end of the beam bolt comes in contact with a top surface of an insert member fitted into an elbow disposed between the pair of projecting portions. An ultrasonic sensor head is fixed to the beam bolt, and ultrasonic waves are sent to the beam bolt from the ultrasonic sensor in the ultrasonic sensor head. An ultrasonic measuring apparatus obtains echo intensity of each of reflected waves generated at the end of the beam bolt and a bottom surface of the insert member, and based on the echo intensities, an echo intensity ratio R is calculated. The installed state of the beam is checked using the echo intensity ratio R.

Abstract: A plant with piping mounted on branch pipe, wherein said piping which introduces gas has a nozzle portion as a joint portion to a vessel and a branch portion connected with a branch pipe; and wherein an enlarged passage portion is formed at least at one of said branch portion and said nozzle portion, and a passage sectional area of said enlarged passage portion is larger than that of said piping other than said enlarged passage portion. Since the flow velocity of the gas flowing inside slows down at the enlarged passage portion, the occurrence of acoustic resonance at the branch portion or the nozzle portion can be suppressed. Accordingly, the fluctuation pressure of the gas flowing in the piping can be reduced even more.

Abstract: A fine motion control rod drive mechanism handling apparatus attaches a fine motion control rod drive mechanism having a control rod drive mechanism body, a spool piece, a motor bracket and a motor unit to a reactor pressure vessel, and detaches it from the reactor pressure vessel. The fine motion control rod drive mechanism handling apparatus is provided with a bolt wrench assembly, a motor unit attachment mounted to the bolt wrench assembly, for meshing a first gear of a first gear coupling on a spool piece side with a second gear of a second gear coupling on a motor unit side, and a rotation mechanism mounted to the bolt wrench assembly, for rotating the motor unit attachment.

Abstract: To provide a plate heat exchanger free from degradation of gaskets which form a flow path through which a high-temperature fluid flows. In the plate heat exchanger, a plurality of heat transfer plates 20 each provided with passage holes 21, 22, 23, and 24 in corners are stacked; a flow-path forming gasket 31 is interposed between peripheries of each adjacent ones of the heat transfer plates 20; communicating-path forming gaskets 32 are installed, surrounding the passage holes 21 in each adjacent ones of the heat transfer plates 20 alternately; and thereby a first flow path 1 adapted to pass a high-temperature fluid H, a second flow path adapted to pass a low-temperature fluid C, and communicating paths 3 adapted to cause the high-temperature fluid H and the low-temperature fluid C, respectively, to flow in and out of the first flow path 1 and the second flow path 2 are formed alternately on opposite sides of each of the heat transfer plates 20.

Abstract: A single-element ultrasonic sensor includes a single transducer element and transmits an ultrasonic wave on the basis of a pulse wave. An ultrasonic array sensor includes a plurality of transducer elements and receives an ultrasonic reflected wave. A pulsar supplies the pulse wave to the single element ultrasonic sensor. A receiver receives electric signals from the transducer elements included in the ultrasonic array sensor. An amplification and conversion unit amplifies the electric signals received from the transducer elements included in the ultrasonic array sensor, converts the electric signals into digital signals, and arranges the digital signals in a serial order so as to generate a serial digital signal. An image generator generates an image on the basis of the serial digital signal.

Abstract: A nozzle apparatus of a jet pump includes a nozzle base member, and a plurality of nozzles installed to the nozzle base member and forming a plurality of narrowing portions, in which a fluid passage cross-sectional area of a driving fluid passage formed in the nozzle is reduced.

Abstract: Heat transfer plates are stacked, each being provided with a plurality of passage holes, a flow-path forming gasket is interposed between peripheries of each adjacent ones of the heat transfer plates, thereby alternately forming a first flow path to pass a high-temperature fluid, a second fluid to pass a low-temperature fluid, and communicating paths to cause the fluids to flow in and out of the first flow path and the second flow path on opposite sides of each heat transfer plate, and communicating-path forming gaskets surrounding the passage holes are interposed between adjacent ones of the heat transfer plates, thereby forming a communicating path to cause a fluid to flow in and out of the first flow path and a communicating path to cause a fluid to flow in and out the second flow path.

Abstract: The invention provides a valve which suppresses a continuous corrosion of a chemical compound phase such as an eutectic carbide or the like in a valve seat, and improves a corrosion resistance, an impact resistance and an erosion resistance of the valve seat. The invention disperses a chemical compound phase such as the eutectic carbide or the like crystallizing in a dendrite gap as a granular shape or a blocky shape which is equal to or less than about 100 ?m, by moving a tool rotating in a crimped state by a load application to a vertical direction to a surface of the valve seat so as to carry out a friction stir processing, and forming a weld metallographic structure of a surface layer portion of the valve seat as a cubic.