Hitachi, Ltd.

Babcock-hitachi Kabushiki Kaisha

Hitachi Engineering Co., Ltd.

Shigeru Kajiyama

Kazuo Takaku

Akisuke Naruse

Masanori Suzuki

Yoshiaki Ichikawa

Ren Morinaka

Yuji Hosoda

Kenji Tsuchita

Chikara Sato

Izumi Kobayashi

Hiroyuki Takeda

Tatsukuma Hosono

Kazuo Yamada

Yousuke Ojiri

Akira Akasu

Shinji Naito

A system for inspection and mending in a reactor vessel of a nuclear reactor comprises a track mechanism, support mechanisms for supporting the track mechanism, an inspection apparatus traveling on the track mechanism, at least one mending apparatus traveling on the track mechanism, a setting mechanism for lowering all the above-described mechanisms and apparatus in the reactor vessel, each of which is composed so as to pass through a hole of an upper grid of a reactor, and an installing mechanism for positioning the support mechanisms fixed with two of the upper grid, a core support plate and internal structures below the core support plate and the track mechanism at the inside of the reactor vessel by remote control and for attaching the inspection apparatus and the mending apparatus to the same track mechanism by remote control. The position data of places to be mended are obtained by the inspection apparatus and transmitted as the target position data to a mending control apparatus for controlling the mending apparatus.

System for inspection and mending in a reactor vessel of a nuclear

A wall-crawling machine comprises a body, a plurality of guide wheels rotatably mounted on the body, at least one crawler track extending around the guide wheels, a plurality of permanent magnets disposed on an outer surface of each of the crawler tracks, and a guide device provided on the respective crawler tracks for selectively restraining or releasing the crawler track from moving relative to the body in a direction perpendicular to a plane on which the permanent magnets travel.

Wall-crawling machine

A guide apparatus comprises an annular rail and jaws for attaching the annular rail onto a cylindrical member to be inspected by an inspecting probe on the rail. The attaching jaws are provided on the rail and include at least two radially stationary jaws and at least one radially movable jaw. Each of the radially stationary jaws has a jaw surface to be abutted on an outer periphery of the cylindrical member. A radial distance between the abutting surface of the radially stationary jaw and the inner peripheral surface of the rail is discontinuously variable.

Guide apparatus

An ultrasonic flaw detector for detecting any flaw existing in the inner peripheral corner section of the joint portion between the barrel of a nuclear reactor pressure vessel and each of a plurality of cylindrical nozzles projecting from the barrel, by means of an ultrasonic wave applied from the outer peripheral corner section of the joint portion. The flaw detector has a probe pivotable around an axis which is made to follow up the locus of the center of curvature in the rounded surface of the outer peripheral corner section during the movement of the probe around the nozzle. According to this arrangement, it is possible to achieve a full automatic and remote control of the flaw detector except the attaching and detaching of the same, and to facilitate the processing of the signals representing the result of the flaw detection.

Ultrasonic flaw detector

An ultrasonic flaw detector device including axial and circumferential fixed tracks located in a space defined between a pressure vessel of a nuclear reactor and a heat insulating wall surrounding the vessel and arranged axially and circumferentially respectively of the pressure vessel of the nuclear reactor. A rotary track is located at a junction of the axial fixed track and the circumferential fixed track and moved in rotary movement by a chain and has its angle of rotation restricted by a pair of stoppers. A carrier member supporting an ultrasonic probe is moved on the tracks to effect ultrasonic flaw detection to detect any flow that might be present in the pressure vessel. To transfer the carrier member from the axial fixed track to the circumferential fixed track, the carrier member is first transferred from the axial fixed track to the rotatable track, and after the rotary track is rotated, the carrier member is transferred from the rotatable track to the circumferential fixed track.

Ultrasonic flaw detector device

An ultrasonic flaw detector is guided around a cylindrical pipe to be inspected by a cylindrical guide rail which is in the form of a split circular ring with a latch and a hinge. On the inner surface of the ring, geared bridge jacks are provided to secure the rings around the outer peripheral surface of the pipe. The ring is mounted to the peripheral surface of the pipe by turning a flexible wire rod connecting respective screws of the jacks. On the outer surface of the rings, a circular guide track and rack are arranged for engagement with the flaw detector.

Cylindrical guide rail for detector

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Hitachi, Japan

Shigeru Kajiyama