By Incineration; By Calcination (e.g., Desiccation) [g21f-9/14] Patents (Class 976/DIG384)
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Patent number: 5732362Abstract: 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.Type: GrantFiled: December 19, 1994Date of Patent: March 24, 1998Assignees: Hitachi, Ltd., Hitachi Engineering & Services Co., Ltd., Hitachi Nuclear Engineering Co., Ltd.Inventors: Tatsuo Izumida, Ryozo Kikkawa, Hiroyuki Tsuchiya, Yoshimasa Kiuchi, Yasuo Hattori
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Patent number: 5545798Abstract: A practical method is described for preparation of radioactive ion-exchange resin for its disposal after the ion-exchange resin has become radioactive in the process of decontaminating radioactive water. Substantially nonradioactive material, which has been derived from the radioactive ion-exchange resin can be disposed of conventionally. The concentration allows corollary reduction of the volume of radioactive waste which must be handled in very costly ways. The radioactive ion-exchange resin and materials that react with the radioactive decaying atoms are heated under controlled atmospheres to (i) form nonvolatile chemicals that hold the decaying atoms, and (ii) under controlled conditions, depolymerize, vaporize, pyrolize, and otherwise decompose and remove nonradioactive components of the ion-exchange resin from the radioactive decaying atoms.Type: GrantFiled: October 24, 1994Date of Patent: August 13, 1996Inventor: Guy R. B. Elliott
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Patent number: 5489737Abstract: 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.Type: GrantFiled: August 4, 1992Date of Patent: February 6, 1996Assignee: Hitachi, Ltd.Inventors: Tsutomu Baba, Masami Matsuda, Takashi Nishi, Koichi Chino, Makoto Kikuchi, Shin Tamata
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Patent number: 5481061Abstract: 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.Type: GrantFiled: October 27, 1993Date of Patent: January 2, 1996Assignee: Hitachi, Ltd.Inventors: Kiyomi Funabashi, Koichi Chino, Osamu Kuriyama, Tsutomu Baba, Shunsuke Uchida, Makoto Kikuchi
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Patent number: 5476989Abstract: An adsorbent useful for the adsorption of radioactive nuclides which comprises fibrous active carbon having a specific surface area of 1,000 m.sup.2 /g or more and an equilibrium moisture regain of 10% or more at a relative humidity of 45%; and a process for the volume-reduction treatment of radioactive liquid waste which comprises subjecting radioactive liquid waste containing radioactive nuclides to an adsorption treatment using an adsorbent comprising fibrous active carbon having a specific surface area of 1,000 m.sup.2 /g or more, and subsequently subjecting the spent adsorbent to an incineration treatment at a temperature which is equal to or higher than the ignition point of the fibrous active carbon.Type: GrantFiled: April 7, 1993Date of Patent: December 19, 1995Assignees: Unitika Ltd., Japan Atomic Energy Research InstituteInventors: Takeo Mimori, Kazutoshi Miyajima, Kouichi Nemoto, Takeshi Nakano, Hirotaka Masui, Tadahiro Mori, Hideki Takahashi
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Patent number: 5276251Abstract: A process for treating organic phosphates, comprising(a) mixing a waste organic solvent mainly composed of an organic phosphate with an additive mainly composed of at least one of metal salts of aliphatic carboxylic acids represented by formula:(C.sub.n H.sub.2n+1 COO).sub.m MwhereinM is K, Ca or Al, andm is a positive integer of 1, 2 or 3,(b) heating the resulting mixture, and(c) optionally burning the mixture to form stable solid containing phosphor content. The metal salts of aliphatic carboxylic acid are preferably metal salts of acetic acid such as potassium acetate, calcium acetate and aluminum acetate. Typical organic phosphate solvent is tributyl phosphate or a mixed solution of tributyl phosphate and benzene.Type: GrantFiled: March 2, 1993Date of Patent: January 4, 1994Assignee: Mitsubishi Nuclear Fuel Co.Inventors: Yoshinobu Kamei, Wataru Shirato