Hitachi, Ltd.

Other

Hitachi Engineering Services Co., Ltd.

Masami Matsuda

Takashi Nishi

Makoto Kikuchi

Koichi Chino

Shin Tamata

Tsutomu Baba

Toshiaki Matsuo

Kiyomi Funabashi

Yoshiyuki Aoyama

Fumio Kawamura

Shunsuke Uchida

Hideo Yusa

Takayuki Matsumoto

Atsushi Yukita

Tatsuo Izumida

Takashi Ikeda

Yoshimasa Kiuchi

Itaru Komori

Katsumi Ohsumi

Susumu Horiuchi

Yamato Asakura

Mamoru Mizumoto

Takeyuki Kondo

Tomohiro Sato

Kazumichi Suzuki

Kenji Noshita

Hideo Hashida

Tsuneyasu Yamanaka

Osamu Kuriyama

Hidetoshi Kanai

Kazuhiko Kudo

Kazuhide Mori

Tetsuro Adachi

Masao Endo

Kiyotaka Ueda

Makoto Kikushi

Akira Sasahiro

Shin Tamada

Takao Ganda

Radioactive laundry liquid wastes are supplied in a liquid waste heating vessel. Hydrogen peroxide and an alkali solution are supplied to the liquid waste heating vessel. The pH of the radioactive laundry liquid wastes is adjusted to 7 or higher by the alkali solution. The radioactive laundry liquid wastes are heated to 50&deg; C. or higher by a heating device and introduced to first and second aeration vessels. The temperature is controlled by a device in accordance with the value measured by a thermometer. Ozone is supplied from an ozone generator by way of an ozone gas discharge port to the first aeration vessel. Ozone discharged from the first aeration vessel is introduced from the ozone gas discharge port to the second aeration vessel. Therefore, the amount of ozone dissolved into the radioactive laundry liquid wastes is increased so that the amount of hydroxy radicals formed for decomposing organic substances increases, since the laundry liquid wastes are heated to 50&deg; C. or higher under the presence of hydrogen peroxide.

Method of and apparatus for treating radioactive liquid wastes containing surface active agents

An incineration and melting furnace has a furnace main body that is filled with a conductive heat generation body (for example, graphite). Radioactive combustible materials in contact with the conductive heat generation body are burnt and the radiaoactive incombustible materials are melted. The resultant exhaust gases and the molten products flow downwardly in the conductive heat generation body filled region and flow out of a molten product discharging port. Noxious gases such as dioxins contained in the exhaust gases are thermally decomposed into a non-toxic state in a high temperature portion of the conductive heat generation region.

Solid material melting apparatus

Radioactive laundry liquid wastes are supplied in a liquid waste heating vessel. Hydrogen peroxide and an alkali solution are supplied to the liquid waste heating vessel. pH of radioactive laundry liquid wastes is adjusted to 7 or higher by the alkali solution. The radioactive laundry liquid wastes are heated to 50&deg; C. or higher by a heating device. The heated radioactive laundry liquid wastes are introduced to first and second aeration vessels. Ozone is supplied from an ozone generator by way of an ozone gas discharge port to the first aeration vessel. Ozone discharged from the first aeration vessel is introduced from the ozone gas discharge port to the second aeration vessel. Therefore, the amount of ozone dissolved into the radioactive laundry liquid wastes is increased so that the amount of hydroxy radicals formed for decomposing organic substances increases, since the laundry liquid wastes are heated to 50&deg; C. or higher under the presence of hydrogen peroxide.

Method of treating radioactive liquid wastes containing surface active agents

Horizontal partition wall 10 is disposed between ceiling slab 9 and floor slab 8. A plurality of storage tubes 6 each accomodating canister 2 are hanging from ceiling slab 9, and penetrate horizontal wall 10 to extend towards floor slab 8. Cooling passages are formed between horizontal partition wall 10 and ceiling slab 9 and between horizontal partition wall 10 and floor slab 8. Cooling air flowing through each of the cooling passages cools down storage tubes 6.

Radioactive waste storage facility

An object of the present invention is to improve retainability (distribution coefficient) for C-14 of a radioactive waste solidified body. The waste is solidified with a solidification agent containing a soluble substance which yields an insoluble substance by a reaction with carbonic ions, insoluble carbonates, or a mixture of the above substances. And, as for a pre-treatment, the soluble substance which yields an insoluble substance by a reaction with carbonic ions is previously reacted with liquid waste, and subsequently the solidification is performed. The retainability (distribution coefficient) for C-14 of the solidified body of the waste increases about one order.

Solidification agents for radioactive waste and a method for processing

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

Objective of the present invention is to provide a preferable solidified body ensuring performance of artificial barrier in a solidifying process for incombustible miscellaneous solid waste and other wastes such as calcined ashes by preventing generation of hydrogen gas by a reaction of amphoteric metal included in the waste with solidifying materials. In order to suppress the reaction of the amphoteric metal with the solidifying materials, any one or arbitrary plurality of the following three means are provided in the solidifying materials; (1) A means for forming protection film on surface of the amphoteric metal, (2) A means for enhancing hydration reaction of cement, (3) A means for reducing basicity of the solidifying materials. In accordance with the present invention, a preferable solidified body can be obtained by a simple and easy method which does not necessitate separation and pre-treatment of the waste.

Method for solidification of waste, and apparatus, waste form, and

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

Method for solidifying radioactive wastes

A process and an apparatus for cleaning nuclear reactor cooling water with cation exchange resin whose ion-exchanging groups have a bonding energy of not more than 300 KJ/mole are disclosed, whereby the radiation exposure of operators in an atomic power plant can be considerably reduced, and the waste ion exchange resin can be readily disposed.

Process and apparatus for cleaning nuclear reactor cooling water

A method and apparatus for analyzing the electrode impedance, in which an a.c. voltage with its frequency varied at intervals is applied between a pair of measuring electrodes dipped in the sample liquid, the complex a.c. impedance between the electrodes is measured at each frequency, the maximum value among absolute values of imaginary part of the measured impedance values is detected as the electrode polarization resistance, and the solution resistance of the liquid is calculated by subtracting the detected maximum value from the real part of the impedance corresponding to the maximum imaginary part.

Method and apparatus for analyzing the electrode inpedance

A method of processing radioactive waste resin by pyrolyzing radioactive waste ion exchange resin generated in a nuclear plant such as a nuclear power station. First, the ion exchange resin is pyrolyzed at a low temperature, and the resulting decomposition gas is separated. Second, the ion exchange resin at a high temperature, and the resulting decomposition gas is separated. Finally, the residue of the ion exchange resin is hot-pressed into a molded article.

Method for processing radioactive waste resin

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 method of processing radioactive spent ion exchange resin, the spent ion exchange resin is pyrolyzed in an inert atmosphere and harmful decomposition gas such as sulfur and nitrogen compounds generated during pyrolysis is separated. Next, the spent ion exchange resin is pyrolyzed in oxidizing atmosphere and harmless gases such as carbon dioxide and water vapor gases are separated. It is preferred that a transition metal as a catalyst be adsorbed through ion exchange into spent cation exchange resin, and an anionic atom group containing a transition metal as a catalyst be adsorbed through ion exchange into spent anion exchange, before both of the pyrolysis steps. The pyrolysis is carried out at two atmosphere stages, and the harmful and harmless gases are decomposed separately. The pyrolysis in both of pyrolysis steps is effected at a temperature in the range of from 240.degree. to 420.degree. C. The proportions of the sulfur and nitrogen compounds in spent ion exchange resin after pyrolysis, and also the processing volume of the spent ion exchange resin can be reduced. And scattering of radioactive substances can be prevented. By adding a catalyst to the spent ion exchange resin, pyrolysis is carried out at a low temperature.

Method and apparatus for processing spent ion exchange resin

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Hitachi, Japan

Masami Matsuda