Hitachi, Ltd.

Koichi Chino

Makoto Kikuchi

Tsutomu Baba

Kiyomi Funabashi

Masami Matsuda

Hideo Yusa

Susumu Horiuchi

Takashi Nishi

Akira Oda

Fumio Kawamura

Shin Tamata

Yoshiyuki Takamura

Osamu Kuriyama

Shunsuke Uchida

Kunio Kamiya

Takashi Ikeda

Hideichi Miura

Kazuhiko Kudo

Osamu Yokomizo

Tetsuo Ito

Mamoru Mizumoto

Mikio Hirano

Toshio Sawa

Tatsuo Hayashi

Kenji Motojima

Masato Ohura

Mitsuo Kinoshita

Yoshiyuki Aoyama

Hiroji Mikawa

Itaru Komori

Eiichi Ga

Makoto Kikushi

Hideichi Mura

Kiroyuki Tsuchiya

Akira Sasahiro

Harumi Wakana

Shin Tamada

An energy storage gas-turbine electric power generating system includes a liquid air storage tank for storing liquid air, a vaporizing facility for vaporizing the liquid air stored in the liquid air storage tank, a combustor for generating a combusted gas by combusting the air vaporized by the vaporizing facility and a fuel, a gas turbine driven by the combusted gas generated in the combustor, and a gas-turbine generator connected to the gas turbine for generating electric power. The system further includes a pressurizing unit for pressurizing the liquid air stored in the liquid air storage tank up to a pressure higher than a pressure of air supplied to the combustor to supply the liquid air to the vaporizing facility, an expansion turbine driven by expanding the air vaporized by the vaporizing facility and an expansion-turbine generator connected to the expansion turbine for generating electric power.

Cold heat reused air liquefaction/vaporization and storage gas turbine electric power system

A processing system for radioactive waste is composed of an adjusting tank having a sampling port, a solidification processing system, and a package inspection apparatus, and a package, of which inventory per a package has been exactly grasped, is prepared by solidification of the waste with the processing system after determining radioactivity of the waste by measurement before the solidifying process. In accordance with the present invention, data on radioactivity before and after preparation of package of waste become clear, and management of each package at transportation and intermediate storage of the packages is facilitated.

Radioactive waste processing system

The present invention relates to a method of solidifying radioactive waste with cement, comprising forming a mixture comprising water, a hydrophilic material and cement substantially non-shrinkable or expansible with respect to volume change upon hardening, mixing said mixture with the radioactive waste, followed by hardening to form a solid body. The present invention enables the formation of a compact solid body having voids, such as capillary voids, of reduced volume, which makes it possible to reduce the leaching rate of hazardous materials. Further, since no shrinkage accompanies hardening, no tensile stress occurs in the cement surrounding minute waste particles within the hardened material, thereby enabling a decrease in the strength of the solid body to be minimized. This in turn enables an increase in the amount of packing of waste. Prior addition of a hydrophilic material enables the cement fluidity before hardening to be maintained even after complete absorption of water by a water absorptive waste. This is extremely advantageous in carrying out hardening.

Method for solidifying radioactive waste

According to the present invention, a fibrous material having a property to adsorb radioactive nuclides in the form of ion or molecule onto its surface is added to a cement type hydraulic solidifying material used for a solidifying material, a waste container, a structure in disposal site and a back-filling material used for production of a waste form of radioactive wastes, whereby improvement of long-term endurance of the waste form, the structure and the like and diminishment of leaching of radioactivity from the waste form and the like can be simultaneously attained.

Solidifying materials for radioactive waste disposal, structures made of

The present invention adds carbonates or chlorides of alkaline earth metals to the radioactive wastes containing sodium sulfate and subjects sulfate group in the radioactive wastes to reduction treatment, thereby converts the sulfate group into sulfides of alkaline earth metals which are chemically stable substances while suppressing SOx generation, and solidifies the radioactive wastes stably for an extended period of time by applying to the converted radioactive wastes solidifying treatment.

Disposal method of radioactive wastes

A method of solidifying a radioactive waste of an atomic power plant, for example, begins with concentrating the liquid waste to powder or pellet form to reduce its volume. Prior to reducing its volume, an estimation is made of what the concentration will be once the liquid waste is converted into powdered or pelletized form. The powdered or pelletized waste is charged into a container, and a solidifying agent is poured over the contents to form a solidified body. The solidifying agent is prepared to have a desired coefficient of distribution that is determined in accordance with the estimated concentration of the reduced volume solidified waste so that the amount of leaching of the solidified body that is produced will be less than or equal to a predetermined value, such as the known value of leaching for a conventional cement-solidified waste that is not processed to reduce its volume before being solidified.

Method and apparatus for solidifying radioactive waste

Method of cementing radioactive waste and cemented body

Method for solidifying radioactive wastes

Waste water concentrator and waste water disposal plant

The present invention provides drying and pulverization of a radioactive liquid waste containing sodium borate as a main component by heating, where the liquid waste is heated, dried and pulverized to substantially crystalline, homogeneous powder of sodium borate while suppressing occurrence of a foaming phenomenon of the powder. The susbtantially crystalline powder is obtained by heating, drying and pulverizing the liquid waste at a temperature outside the temperature range where the salt powder takes an amorphous state in the course of releasing water of crystallization from the salt powder. In the drying and pulverization of a liquid waste containing sodium borate by a thin film evaporator, occurrence of the foaming phenomenon can be suppressed by maintaining the temperature on the heat transfer surface of the evaporator at a temperature lower than 150.degree. C.

Process for treating radioactive liquid waste containing sodium borate

Disclosed is a control system for a centrifugal thin film dryer wherein a slurry including solid matter is fed to a tubular heating surface and the a slurry is heated while blades are rotating inside the heating tube so that the a slurry turns into dry powder, the system comprising a plurality of thermal sensors located on the heating surface, a dry-up point calculator which measures the temperature distribution along the heating surface in accordance with the signals provided by the thermal sensors and calculates the point at which the temperature rise begins to saturate, a flow rate setting device which calculates the quantity of a slurry to be supplied in accordance with the output of the dry-up point calculator, and a flow rate regulator which controls a pump in accordance with the signal provided by the flow rate setting device.

Method and apparatus for controlling centrifugal thin film dryer

A method for processing spent radioactive ion exchange resin formed in a nuclear power plant by a two-step pyrolysis method. First, the spent resin is heated at 350.degree. C. to decompose functional groups selectively. Then the base polymer, formed as residue, is decomposed at a temperature above 350.degree. C., e.g. 600.degree. C. After the thermal decomposition, exhaust gases which require a special exhaust gas disposal means, such as NO.sub.x and SO.sub.x can be reduce to below 1/20.

Method of disposing radioactive ion exchange resin

In a treatment system of radioactive waste solution including sodium sulfate generated from a boiling water type nuclear reactor, waste solution is fed into a thin film evaporator where the waste solution is evaporated and made into powder while precipitating in a peripheral surface of the evaporator vessel. The surface of the precipitated solid is wiped by rotating wiper blades and removed off as radioactive solid powder. The rotational speed of a rotor to which the wiper blades are secured is controlled at a minimum and necessary rotational speed which contributes to make the waste solution into the powder so that the rate of worn out of the wiper blade is decreased.

Process and system for treatment of radioactive waste

A detergent-containing radioactive liquid waste originating from atomic power plants is concentrated to have about 10 wt. % detergent concentration, then dried in a thin film evaporator, and converted into powder. Powdered activated carbon is added to the radioactive waste in advance to prevent the liquid waste from foaming in the evaporator by the action of surface active agents contained in the detergent. The activated carbon is added in accordance with the COD concentration of the radioactive liquid waste to be treated, and usually at a concentration 2-4 times as large as the COD concentration of the liquid waste to be treated. A powdery product having a moisture content of not more than 15 wt. % is obtained from the evaporator, and pelletized and then packed into drums to be stored for a predetermined period.

Process for treatment of detergent-containing radioactive liquid wastes

A granulating apparatus comprising a device which adds a binder of an epoxy resin or the like into a powder to-be-treated, a screw feeder which conveys the powder to-be-treated containing the binder, and rolls which compression-molds it. By rotating the screw feeder and the rolls, the powder to-be-treated is caused to induce internal friction and to generate heat, thereby to temporarily dissolve the binder, whereupon the powder to-be-treated is pelletized. In order to temporarily dissolve the binder, the granulating apparatus is equipped with a device for measuring the temperature of the powder to-be-treated, and a controller for controlling the stirring speed of the screw feeder and the molding speed of the rolls on the basis of the measured value so as to establish a desired temperature.

Granulating apparatus

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Hitachi, Japan

Koichi Chino