Hitachi, Ltd.

Hitachi Engineering Co., Ltd.

Takashi Honda

Katsumi Mabuchi

Michihiko Aizawa

Katsumi Ohsumi

Heihatiro Midorikawa

Tomoko Kikuchi

Masahiko Ito

Akira Minato

Yasumasa Furutani

Kenya Ohashi

Masakiyo Izumiya

Eizi Kashimura

Yuko Sasaki

Motohiro Aizawa

Shiro Kobayashi

Akira Uenishi

Hisao Itow

Toshio Kawakami

Kazuo Tanno

Hisao Itou

Saburo Shoji

Eiji Kashimura

An absorption refrigerator includes a high temperature regenerator for heating a water solution including a halogen compound to generate steam. An oxide film having thickness of 0.02&#x2013;5.0 &#x3bc;m, one of the colors blue, purple and gray, or a hydroxyl group is formed on a surface of at least one of the high temperature regenerators and the heat exchanger.

Absorption refrigerator and production method thereof

An absorption refrigerator includes a high temperature regenerator for heating a water solution including a halogen compound to generate steam. An oxide film having thickness of 0.02-5.0 &mgr;m, one of the colors blue, purple and gray, or a hydroxyl group is formed on a surface of at least one of the high temperature regenerators and the heat exchanger.

An absorption refrigerator uses water as a refrigerant and a halogen compound as an absorption solution, and is characterized in that an oxide film of thickness of 0.02-5.0 .mu.m is formed on a surface of at least one of a heat exchanger and a high temperature regenerator. And a production method of the absorption refrigerator is characterized by oxidizing a surface of at least one of a heat exchanger and a high temperature regenerator at a temperature of 200-800.degree. C., and adjusting a heating temperature and a heating retaining time so that a value of parameter (P), obtained according to P=T (5+log t) is 3.5-6.0.times.10.sup.3, wherein T represents heating temperature (.degree.K), and t heating retaining time (minute).

An absorption refrigerator uses water as a refrigerant and a halogen compound as an absorption solution, and is characterized in that an oxide film of thickness of 0.02-5.0 .mu.m is formed on a surface of at least one of a heat exchanger and a high temperature regenerator. And a production method of the absorption refrigerator is characterized by oxidizing a surface of at least one of a heat exchanger and a high temperature regenerator at a temperature of 200.degree.-800.degree. C., and adjusting a heating temperature and a heating retaining time so that a value of parameter(P), obtained according to P=T (5+log t) is 3.5-6.0.times.10.sup.3, wherein T represents heating temperature (.degree.K), and t heating retaining time (minute).

Nuclear fuel reprocessing plant

In a boiling water-type, nuclear power plant, deposition of radioactive substances on the surfaces of out-of-core components in the primary cooling water system in the nuclear power plant is suppressed by injecting an alkaline element into reactor water in the presence of more than an amount of the oxygen formed by nuclear fission of the reactor water and dissolved in the reactor water, particularly without hydrogen gas injection, during the nuclear heatup operation period of a boiling water type, nuclear power plant and circulating the injected alkaline element through the primary cooling water system of a nuclear reactor, thereby forming an oxide film on the surfaces of out-of-core components in the primary cooling water system of the nuclear reactor. Exposure of plant personnel to radioactivity can be reduced thereby. The present boiling water-type, nuclear power plant is provided with a means for forming such oxide film.

Suppression of deposition of radioactive substances in boiling water

A nuclear power plant wherein surfaces of components contacting with nuclear reactor cooling water containing radioactive substances are coated with an oxide film, preferably being charged positively and/or containing chromium in an amount of 12% by weight or more, is prevented effectively from the deposition of radioactive substances thereon.

Inhibition of deposition of radioactive substances on nuclear power

The present invention is concerned with a method of reducing radioactivity in a nuclear plant by preliminarily forming oxide films on the surfaces of metallic structural members to be in contact with high-temperature and high-pressure reactor water containing radioactive substances before said metallic members are exposed to said reactor water. The method is characterized by the steps of subjecting said structural members to a first-step oxidation treatment of heating said structural members in an environment of a high temperature, and further subjecting the thus treated structural members to a second step oxidation treatment of heating said treated structural members in an environment having a higher oxidizing capacity than that of said environment in said first-step oxidation treatment to form a denser oxide film than an oxide film obtained in said first step oxidation treatment. According to the present invention, radioactivity in the nuclear plant can be reduced remarkably.

Method of reducing radioactivity in nuclear plant

A nuclear power plant using a structural material consisting of metal which comes into contact with a liquid in which radioactive substances are dissolved has a function to suppress the deposition of the radioactive substances. In this function, metal elements constituting the surface layer of the structural material which comes into contact with the liquid are oxidized by injecting oxidizing agents from outside, thereby preliminarily producing an oxide film. The oxidizing agents comprise at least one kind selected from the group consisting of oxygen, hydrogen peroxide, chromate, nitrite, molybdate, tungstate and ferrate. Particularly, by suppressing the deposition of radioactive substances on a stainless steel, the dose rate of exposure of workers is effectively reduced.

Nuclear power plant providing a function of suppressing the deposition

A method of inhibiting corrosion of carbon steel piping of condensate and feed water systems in a power generating plant, characterized by continuing the water in said piping to flow after also said plant has been shut down until it is restarted up and by keeping the specific electric conductivity of flowing water at 0.5 .mu.S/cm or less.

Method of inhibiting corrosion of carbon steel piping of condensate and

A hydrogen generating apparatus comprising a cell having a plurality of chambers defined in the cell by cation exchange membranes and anion exchange membranes arranged alternately, a high concentration electrolyte and a low concentration electrolyte being filled alternately in said plurality of chambers, and a pair of electrodes guided into the chambers disposed on both the ends of said cell, respectively, and the open circuit voltage between said electrodes being higher than the decomposition voltage of water.

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Ibaraki, Japan

Takashi Honda