Hitachi-ge Nuclear Energy, Ltd.

Hitachi, Ltd.

Satoru Aoike

Masakazu Hisatsune

Kenji Araki

Koichi Kurosawa

Masatoshi Takada

Masafumi Noujima

Kenji Utaka

Chikara Takeuchi

Satoshi Kanno

Shinya Ohmori

Shinobu Okido

Masaaki Tanaka

Junya Kaneda

Norio Kawashima

Hirofumi Oizumi

Masaki Tsuruki

Yuka Fukuda

Naohiko Oritani

Katsumasa Miyazaki

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.

Underwater remote inspection device and method for underwater remote inspection

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.

Method for improving residual stress in pipe and method for construction management

A control rod for a boiling water reactor is provided with a structure element having mutually-perpendicular four blades. The four blades have a neutron absorber-filling region that neutron absorber is held, respectively. In the structure element, a plurality of regions formed in an axial direction of the control rod include a first region having a first cross-section that forms a first united cruciform cross-section of the four blades connected one another, a second region having a second cross-section that has each separated cross-section of the four blades, and a third region having a third cross-section that has a second united cross-section of continuous two blades of the four blades, disposed in a diametrically opposite direction and facing each other and each separated cross-section of remaining two blades of the four blades, disposed perpendicularly to the continuous two blades.

Control rod for boiling water reactor

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.

Electrolytically etching method and apparatus of surface of nuclear reactor core internals

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. As a result, the gas bubbles or the liquid bubbles do not remain in the surface of the replica agent contacting with the surface of the core internal structure.

Underwater remote surface inspection method and apparatus for reactor constituting member

An method for converting tensile residual stress on an inner surface of a welded part of a pipe to compressive residual stress with use of ice plugs formed by cooling the pipe from the outer surface, comprises the steps of: placing refrigerant containers for forming the ice plugs in the upstream and downstream of a butt-welded part; cooling the outer surface of the pipe to form the ice plugs; and then cooling the outer surface of the pipe with use of at least one refrigerant container for expanding the pipe arranged between the refrigerant containers for forming the ice plugs. When the method is applied to a pipe with a large inside diameter, the method comprises forming the ice plugs at a curved pipe, an elbow or a branch pipe in the upstream and downstream of the butt-welded part.

Method for improving residual stress in pipe and apparatus

A wall-thickness thinning rate at a not-measured position is estimated using information having a small number of measured points. Simulation of behavior of fluid flowing inside a pipe line is performed based on wall-thickness data of pips and three-dimensional layout data of the pipe line including the pips using a computer, and simulated wall-thickness thinned data of the pipes composing the pipe line is calculated from change of the simulated behavior of fluid.

Method of offering wall-thickness thinning prediction information, and computer-readable recording medium storing wall-thickness thinning prediction program, and method of planning piping work plan

A wall-thickness thinning rate at a not-measured position is estimated using information having a small number of measured points. Simulation of behavior of fluid flowing inside a pipe line is performed based on wall-thickness data of pipes and three-dimensional layout data of the pipe line including the pipes using a computer, and simulated wall-thickness thinned data of the pipes composing the pipe line is calculated from change of the simulated behavior of fluid.

In a thickness reducing management for pipes in pipe lines, limited proper parameters which cause erosion and corrosion of the pipes are selected and with these parameters a pipe thickness reducing speed evaluation model formulas are constructed, and by making use of the model formulas thickness reducing amount of the pipes is evaluated. Thereby, conventional difficulty of formulating a proper pipe thickness reducing estimation model formula in view of actual pipe material and pipe inner fluid state because of too many possibly influential parameters causing pipe thickness reducing due to erosion and corrosion, and conventional difficulty of performing highly reliable pipe thickness reducing management are overcome.

Growing community of inventors

Tokai, Japan

Satoru Aoike