Hitachi, Ltd.

Hitachi Engineering Services Co., Ltd.

Hitachi Nuclear Engineering Co., Ltd.

Hitachi Engineering Co., Ltd.

Hiroyuki Tsuchiya

Makoto Kikuchi

Hideo Yusa

Kunio Kamiya

Yoshimasa Kiuchi

Kiyomi Funabashi

Yamato Asakura

Tatsuo Izumida

Ryozo Kikkawa

Teiji Suzuki

Takahiro Sanada

Yasuo Hattori

Shoichi Ouchi

The present invention relates to a method for treating radioactive laundry waste water generated from a nuclear power plant, nuclear fuel reprocessing plant, or radioactive nuclides handling facilities, and provides a method for treating the waste water safely and for reducing the volume of generated radioactive waste to a minimum. Radioactive laundry waste water containing a detergent of which major contents are a nonionic surface active agent and inorganic builders is concentrated by an evaporating concentrator, the concentrated waste water is dried and pulverized to dry powder by a rotary centrifugal thin film dryer, and the dry powder is incinerated. By using the above detergent, foaming at the concentration can be reduced, and the concentrated waste water can be easily dried and pulverized. Further, the dried powder can be incinerated stably and safely without influencing undesirable effect on the body of the incinerator. In accordance with the present invention, laundry waste water can be treated simply and safely, and the final volume of radioactive waste can be reduced to minimum.

Method for treating radioactive laundry waste water

A vessel for solidifying radioactive waste pellets includes a vessel body, an inner lid mounted within the vessel body and fixedly secured to an upper portion of the vessel body, and a device for preventing the pellets from floating fixedly secured one end thereof to the inner lid. The inner lid has an opening formed at a generally central portion thereof, and the pellet float prevention device is extended into the opening of the inner lid to define gaps therebetween allowing the passage of a solidifying material in the state of a liquid or a slurry therethrough but preventing the passage of the radioctive waste pellets therethrough. The pellet prevention device, when receiving a downward urging force, is bent downward to enlarge the gaps therebetween for allowing the radioactive waste pellets to pass therethrough. The pellet float prevention device is returned by a resilient restoring force to its initial position when the downward urging force is released. The pellet float prevention device comprises a plurality of coil springs fixedly secured to the inner lid in a radial manner, and some of the plurality of coil springs extend to an area close to the center of the opening in the inner lid. The coil springs are extended in such a manner that the axis of each of the coil springs is displaced a predetermined angle from the center of the opening in the inner lid.

Vessel for solidification treatment of radioactive waste pellets

Hydrogen isotope is separated and recovered with remarkable reduction in energy consumption in a compact apparatus using a cold reactor and a hot reactor based on dual temperature process by a combination of a first step of at least one isotope exchange reaction stage comprising contacting mists of a feed liquid cocurrently together with a reacting gas with an isotope exchange reaction catalyst at a low temperature, and a second step of a plurality of stages each comprising a gas-liquid contact of the liquid from the first step with vapor of the liquid and the reacting gas and an isotope exchange reaction between the vapor of the liquid and the reacting gas at a high temperature.

Process for separating and recovering hydrogen isotope

An iodine adsorbent comprises a carrier, a film of iodine-adsorbing material or compound deposited on the surface of the carrier, and a layer of organic material coated on the surface of the film, and has a high iodine removal efficiency at a high humidity.

Iodine adsorbent

A metallic catalyst of three-layer structure of a carrier metal, an interlayer metal having a heat-insulating property by itself, or an interlayer metal capable of forming an oxide having a heat-insulating property or a catalyst surface area-increasing property, deposited on the entire surface of the carrier metal, and a catalyst metal deposited on the interlayer metal is prepared in a shorter production time at a lower cost through simplified process steps by depositing the interlayer metal and the catalyst metal by plating, if necessary, followed by oxidation, or both oxidation and reduction. The metallic catalyst has an improved catalytic activity, especially at a low temperature, in addition to the high mechanical strength.

Metallic catalyst and process for preparing the same

Hydrocarbons are removed from a waste gas including oxygen, hydrocarbons and radioactive Krypton-85 (hereinafter referred to as 'Kr-85'), which is generated in a nuclear reactor and a fuel recycling plant without adopting the reduction method of oxygen by adding hydrogen; the resultant gas is caused to pass through an activated charcoal layer and Kr-85 is adsorbed to the activated charcoal layer; the rest of gas is discharged to the atmosphere; further oxygen remaining in the activated charcoal layer is returned to a process of removing hydrocarbons; and thereafter Kr-85 adsorbed to the activated charcoal layer is desorbed, condensed and recovered.

Growing community of inventors

Hitachi, Japan

Hiroyuki Tsuchiya