Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Hitachi-ge Nuclear Energy, Ltd.

Masanori Takahashi

Mitsushi Abe

Takeshi Nakayama

Hiroyuki Watanabe

Masanori Sakai

Makoto Hayashi

Makoto Nagase

Katsumi Ohsumi

Yamato Asakura

Noriyuki Ohnaka

Manabu Aoki

Hidefumi Ibe

Yasuko Aoki

Takashi Saito

Tetsuo Fukasawa

Kiyotomo Nakata

Jun Kawamura

Akira Sasahira

Mamoru Kamoshida

Kazuhiko Akamine

Youji Shibata

Main coils, counteracting coils and correction coils, each forming superconducting coil, are enclosed in two cooling medium chamber facing to each other and an imaging region is formed between the two cooling medium chamber positioned in each vacuum chamber, the main coils being divided into two pieces to reduce the current density and the maximum experience magnetic filed and compression stress.

Superconducting magnet apparatus

The electromagnet apparatuses generate a homogeneous magnetic field in a homogeneous magnetic field region by a pair of superconductive main coils for facing to each other; a pair of superconductive shielding coils for facing to each other and passing a current in a direction reverse to that of the main coils; and a pair of first ferromagnetic members for facing to each other, and the apparatuses further include a pair of second ferromagnetic members for facing to each other and be disposed in contact with or adjacent to an opposite side of the region side of the first ferromagnetic members, wherein the region is interposed between the main coils, between the shielding coils, between the first members whose outer periphery is a circle, and between the second members whose outer periphery is a circle whose diameter is larger than that of the circle of the first members.

Electromagnet apparatus generating a homogeneous magnetic field with ferromagnetic members arranged inside cryogenic vessels

A super-conducting magnet apparatus in an MRI system which may reduce unevenness among magnetization characteristics of ferromagnetic elements arranged between super-conductive shield coils and superconducting main coils. There are provided a pair of super-conducting main coils, a pair of superconductive shield coils arranged on the axes of the pair of super-conducting main coils, being spaced from the pair of super-conducting main coils, and also arranged on opposite sides of a zone to be observed, and ferromagnetic elements arranged in parts of spaces extending from air core parts of the super-conducting main coils to air core parts of the super-conductive shield coils. The super-conductive shield coils have an outer diameter which is larger than that of the super-conducting main coils. The ferromagnetic elements are composed of a plurality of axially symmetric ferromagnetic members which are coaxially arranged, and which have a space in at least a radial part thereof, but not in a center axis part. With this configuration, the magnetic saturation of the ferromagnetic members may be facilitated. Thereby it is possible to reduce the effect of unevenness among magnetization characteristics of the ferromagnetic elements.

Superconductive magnetic apparatus for magnetic resonance imaging unit

Most part of an amount of uranium contained in the spent nuclear fuel is removed by making fluorine or a fluorochemical act on the spent nuclear fuel to convert the uranium into UF, and the uranium is purified through a simple method of distilling the UFtogether with a absorbent. After removing the most part of the amount of uranium, the remaining nuclear fuel material is dissolved and then transferred to an extraction process to recover plutonium. By doing so, a small sized dry process can be employed as a uranium purification process. Since the nuclear fuel material is dissolved and extracted after removing most part of an amount of uranium, a volume of processing solution can be reduced and the machine installation scale can be made small. Accordingly, the reprocessing facility can be extremely downsized.

Method of reprocessing spent nuclear fuel

An MRI apparatus includes magnet members for compensating the magnetic field which are disposed to a thermal shield system of the superconducting apparatus. The magnet members for compensating the magnetic field are disposed at positions where temperature change in the vacuum chamber is not transferred to the interior of the vacuum chamber.

Superconducting magnet apparatus and magnetic resonance imaging apparatus using the same

A water chemistry factor which is specific to a specific portion of a primary cooling system and universal is decided to be a standard target. The concentration of an agent for mitigating corrosion damage of structural material of the primary cooling system is controlled so that the target will be in a desirable range. All sensor groups provided in the primary cooling system are separated into sensor groups in different lines, of which a specific sensor group are connected to an arithmetic unit and a data base and are for always monitoring a plant process. For example, concentration distribution agreed with measured value oxidation component in the reactor water at the measurement points is selected from the data base, and it is used to estimate the standard target.

Nuclear power plant having a water chemistry control system for a

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Mito, Japan

Masanori Takahashi