Hitachi, Ltd.

Kunio Hasegawa

Masahiro Otaka

Makoto Hayashi

Kunio Enomoto

Tasuku Shimizu

Kazuo Takaku

Toshihiko Yoshimura

Yuichi Ishikawa

Motoya Ito

Kiyoshi Yamaguchi

Satoshi Kanno

Koichi Kurosawa

Shinji Sakata

Tetsuo Horiuchi

Takashi Saito

Hideyo Saito

Yoshinori Karatsu

Stephen Evanson

Yuko Koguchi

Hidetomo Nishimura

Hisao Ito

A fluxmeter includes an application unit for applying a magnetic field, a superconducting quantum interference element and a flux transmitting circuit. The flux transmitting circuit includes a pickup coil formed of a superconducting print coil and a core for the pickup coil. The core is formed of a soft magnetic material. The core serves to suppress the leakage of magnetic flux to magnetically couple the pickup coil and the superconducting quantum interference element efficiently to improve the sensitivity and resolution of the fluxmeter. The pickup coil may be manufactured by photolithography, sputtering, laser beam deposition, MBE deposition, MOCVD or spray pyrolysis.

Fluxmeter including squid and pickup coil with flux guiding core and

A non-destructive inspection apparatus includes a magnetic field applying device and a magnetic sensor. The magnetic field applying device is adapted to apply DC and AC magnetic fields to an object to be inspected. Degradation/damage of the object is detected by measuring a magnetic characteristic of the object in a state in which the DC and AC magnetic fields are applied. Also, a non-destructive inspection apparatus includes as a magnetic sensor a plurality of pickup coils and a SQUID(s) connected to the pickup coils and decides the form of a defect of an object to be inspected by producing a difference between outputs of the pickup coils or SQUIDs.

Apparatus for inspecting degradation/damage of a material using an AC

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 portion inside of the housing, which has been yielded, so as to tensile-yield the inner surface of the housing by using a cooling device inserted into the housing from a lower portion, whereby compressive stress is allowed to remain in the tensile-yielded portion.

Method of maintaining housing of reactor pressure vessel and heat

On the basis of a finding that a magnetic hysteresis of a metal material, among magnetization characteristics changing with secular degradation of the metal material, shows a clear correspondence with the degree of degradation of the metal material, a change in such a magnetization characteristic is measured to estimate the degree of secular degradation of the metal material. In a typical embodiment, a superconducting quantum interference device is used to detect the magnetization characteristic of a measuring object. According to the present invention, the degree of embrittlement of a metal material used in an environment of high temperatures can be quickly detected in a non-destructive fashion so that the danger of brittle fracture of the metal material can be reliably prevented.

Apparatus for magnetically detecting degradation of metal material using

On the basis of a finding that a magnetic hysteresis of a metal material, among magnetization characteristics changing with secular degradation of the metal material, shows a clear correspondence with the degree of degradation of the metal material, a change in such a magnetization characteristic is measured to estimate the degree of secular degradation of the metal material, In a typical embodiment, a superconducting quantum interference device is used to detect the magnetization characteristic of a measuring object. According to the present invention, the degree of embrittlement of a metal material used in an environment of high temperatures can be quickly detected in a non-destructive fashion so that the danger of brittle fracture of the metal material can be reliably prevented.

Method and apparatus utilizing a magnetic field for detecting

Piping of a nuclear reactor containment vessel comprises pipes passing through the containment vessel and, extending to the outside of the containment vessel, outer shut-off valves each provided at a portion of the pipe which is located at the outside of the containment vessel for closing the pipe and isolating vessels for covering at least outer surfaces of welded portions of the pipes each being located between an outer wall surface of the containment vessel and a portion including the outer shut-off valve and for isolating the covered portions of the pipes from atmosphere.

Piping of nuclear reactor containment vessel

A rotor for a rotary electrical machine having a superconductive field winding, wherein thermal resistance means is arranged at contact parts between a damper, which is so disposed as to cover the superconductive field winding, and a damper support which supports the damper from the inner side thereof. A plurality of protuberances are formed on either said damper support or said damper for restricting heat flow between said damper and said damper support. It is possible to cause a cooling medium to flow through interstices which are defined at the contact parts between the damper and the damper support.

Rotor for a rotary electrical machine having a superconductive field

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Katsuta, Japan

Kunio Hasegawa