Kabushiki Kaisha Toshiba

Yumi Yaita

Masami Enda

Hitoshi Sakai

Ichiro Inami

Takeshi Kanasaki

Mitsuyoshi Sato

Yutaka Uruma

Hiromi Aoi

Seiji Yamamoto

Toshihiro Yoshii

Masaaki Kaneko

Koji Mizuguchi

Reiko Fujita

Seiichi Murayama

Takaaki Murata

Nagayoshi Ichikawa

Takashi Yazawa

Hajime Hirasawa

Norihisa Saito

Shohei Kanamura

Yuya Takahashi

Masayuki Kaneda

Yoshinari Takamatsu

Takashi Omori

Shinya Miyamoto

Toshiaki Sugimori

Yu Yamashita

Tetsuo Osato

Teruki Fukumatsu

Satoshi Hiraragi

A treatment method for a used ion exchange resin, includes: bringing a used ion exchange resin into contact with a reaction solution, the used ion exchange resin having an ion exchange group with at least a radionuclide or a heavy metal element adsorbed thereon, and the reaction solution containing an iron compound, hydrogen peroxide, and ozone; separating at least a part of the reaction solution in contact with the used ion exchange resin from the used ion exchange resin; and decomposing an organic component contained in the reaction solution separated from the used ion exchange resin.

Treatment method for used ion exchange resin

A radioactive substance is effectively suppressed by an oxide-film removal step of removing an oxide film on a metallic material surface with which a coolant containing the radioactive substance comes in contact, and a titanium-oxide deposition step of depositing a titanium oxide on the metallic material surface after the oxide film has been removed.

Method of and system for suppressing deposition of radioactive substance

According to one embodiment, a process for producing rare metals includes the steps of: recovering a first-residue solution through a primary target metal extracted by leaching a mineral resource; extracting a perrhenic acid ion contained in the first-residue solution with at least one of an anion exchange resin and a first-organic solvent; back extracting the perrhenic acid ion contained in the anion exchange resin or the first-organic solvent to a first-eluant; and electrolyzing the back extracted first-eluant to collect a rhenium at a cathode.

Process for producing rare metal

A radiation exposure reduction method includes the steps of: injecting iron into a coolant which flows from the reactor cooling system to the reactor core in a nuclear power plant; and ferritizing and fixing radionuclides or parent nuclides thereof, which are contained in the coolant, on the surface of a reactor core structure, wherein an iron citrate which is soluble organic iron, or iron oxalate or iron fumarate which has a particle diameter of 3 &#x3bc;m or less, is used as the iron to be injected into the coolant.

Radiation exposure reduction method

A chemical decontamination apparatus of the present invention chemically dissolves radioactive substance-containing oxide films formed or adhering on the surface of a decontamination object by using ozone water to conduct decontamination. The chemical decontamination apparatus includes an ozone generating unit for generating ozone gas, an ozone supplying device for supplying the generated ozone gas to an ozone supplying unit in water, and a sintered metal elementwhich is disposed in the ozone supplying unit and to which ozone gas is supplied from the ozone supplying device. The ozone gas supplied to a sintered metal element interior from the ozone supplying device is allowed to flow out of the element into water so as to generate ozone water.

Chemical decontamination apparatus and decontamination method therein

A system for chemically decontaminating radioactive material.

System and method for chemical decontamination of radioactive material

Chemical decontamination method of dissolving oxide film adhered to contaminated component including, preparing decontamination solution in which ozone is dissolved and oxidation additive agent, which suppresses corrosion of metal base of the contaminated component, is added, and applying the decontamination solution to the contaminated component, thereby to remove the oxide film by oxidation.

Method for treating a chemical decontamination solution

A method for chemically decontaminating radioactive material. The method includes reducing-dissolving step for setting surface of radioactive material in contact with reducing decontamination liquid including mono-carboxylic acid and di-carboxylic acid as dissolvent; and oxidizing-dissolving step for setting the surface of the radioactive material in contact with oxidizing decontamination liquid including oxidizer. The method may include repeated pairs of steps, each pair including the reducing-dissolving step and the oxidizing-dissolving step. The mono-carboxylic acid may include formic acid, and the di-carboxylic acid includes oxalic acid. The oxidizer may be ozone, permanganic acid or permanganate.

Ozone gas having a high ozone concentration is generated by a solid electrolyte electrolytic process. An ozone solution is prepared by injecting the ozone gas into an acidic solution of pH 6 or below. The ozone solution heated at a temperature in the range of 50&#xb0; to 90&#xb0; C. is supplied to a contaminated object to oxidize and dissolve a chromium oxide film by an oxidizing dissolving process. The ozone solution used in the oxidizing dissolving process is irradiated with ultraviolet rays to decompose ozone contained in the ozone solution, the ozone solution is passed through an ion-exchange resin to remove ions contained in the ozone solution. An oxalic acid solution is supplied to the contaminated object to dissolve an iron oxide film by a reductive dissolving process. Oxalic acid remaining in the oxalic acid solution after the reductive dissolving process is decomposed by injecting ozone into the oxalic acid solution and irradiating the oxalic acid solution with ultraviolet rays, and ions contained in the oxalic acid solution is removed by an ion-exchange resin.

Method of chemically decontaminating components of radioactive material handling facility and system for carrying out the same

Ozone gas having a high ozone concentration is generated by a solid electrolyte electrolytic process. An ozone solution is prepared by injecting the ozone gas into an acidic solution of pH 6 or below. The ozone solution heated at a temperature in the range of 50&deg; to 90&deg; C. is supplied to a contaminated object to oxidize and dissolve a chromium oxide film by an oxidizing dissolving process. The ozone solution used in the oxidizing dissolving process is irradiated with ultraviolet rays to decompose ozone contained in the ozone solution, the ozone solution is passed through an ion-exchange resin to remove ions contained in the ozone solution. An oxalic acid solution is supplied to the contaminated object to dissolve an iron oxide film by a reductive dissolving process. Oxalic acid remaining in the oxalic acid solution after the reduction dissolving process is decomposed by injecting ozone into the oxalic acid solution and irradiating the oxalic acid solution with ultraviolet rays, and ions contained in the oxalic acid solution is removed by an ion-exchange resin.

Growing community of inventors

Tokyo, Japan

Yumi Yaita