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Owada, Mitsuhiro; Nakanishi, Yoshiki; Murokawa, Toshihiro; Togashi, Kota; Saito, Katsunori; Nonaka, Kazuharu; Sasaki, Yu; Omori, Koji; Chinone, Makoto; Yasu, Hideto; et al.
JAEA-Technology 2024-013, 221 Pages, 2025/02
JAEA-Technology-2024-013.pdf:14.98MB
The uranium enrichment facilities at the Nuclear Fuel Cycle Engineering Laboratories of Japan Atomic Energy Agency (JAEA) were constructed sequentially to develop uranium enrichment technology with centrifugal separation method. The developed technologies were transferred to Japan Nuclear Fuel Limited until 2001. And the original purpose has been achieved. Wastewater Treatment Facility, one of the uranium enrichment facilities, was constructed in 1976 to treat radioactive liquid waste generated at the facilities, and it finished the role in 2008. In accordance with the Medium/Long-Term Management Plan of JAEA Facilities, interior equipment installed in this facility had been dismantled and removed since November 2021 to August 2023. This report summarizes the findings obtained through the work related to dismantling and removal of interior equipment for decommissioning of Wastewater Treatment Facility.
Nakanishi, Yoshiki; Aoyama, Yoshio; Nonaka, Kazuharu; Sone, Tomoyuki; Nakazawa, Osamu; Tashiro, Kiyoshi
JAEA-Testing 2011-008, 31 Pages, 2012/03
JAEA-Testing-2011-008.pdf:2.8MB
Steam reforming technology has been developed to reduce the volume of liquid uranium waste such as a Tri-n-butyl phosphate adding n-dodecane solvent (TBP/nDD), which is difficult to incinerate. The localized corrosion like pitting corrosion occurred on the inner surface of the gasification chamber of the demonstration scale steam reforming system during the treatment of TBP/nDD. Therefore we conducted the corrosion tests to identify the form of corrosion. It is found that the form of corrosion is crevice corrosion which caused by the residues generated by treatment of TBP/nDD. The cathodic protection system using a galvanic anode was selected as the corrosion protection method of the gasification chamber. The continuous treatment test of TBP/nDD was conducted using the steam reforming system with the cathodic protection system. As a result, the crevice corrosion did not occur during 600 hours continuous treatment of TBP/nDD, and the effectiveness of the protection method was verified.
Sone, Tomoyuki; Nakagawa, Akinori; Koyama, Hayato; Gunji, Kiyoshi; Nonaka, Kazuharu; Sasaki, Toshiki; Tashiro, Kiyoshi; Yamashita, Toshiyuki
JAEA-Technology 2009-023, 33 Pages, 2009/06
JAEA-Technology-2009-023.pdf:8.11MB
Steam reforming (SR) method consists of the gasification process in which organics are vaporized and decomposed with superheated steam and the oxidation process in which vaporized organics are decomposed by oxidizing reaction with heated air. 2,500L of waste TBP/n-dodecane contaminated with uranium was treated using the demonstration scale steam reforming system to examine the performance of the system. Results obtained in this study show that the temperature in the SR system was controlled under the self-regulation temperature, the concentration of CO and NOx in the off-gas were controlled less than 100ppm and 250ppm respectively, the distribution ratio of uranium to off-gas treatment system was under 0.12% and the gasification ratio of waste TBP was more than 99%. This long-term waste treatment test has demonstrated that the SR system can safely and effectively reduce the volume of the waste.
Sone, Tomoyuki; Nonaka, Kazuharu; Sasaki, Toshiki; Yamaguchi, Hiromi
JAEA-Technology 2008-006, 23 Pages, 2008/03
JAEA-Technology-2008-006.pdf:3.54MB
Steam reforming method consists of the gasification process (GP) in which organics are vaporized and decomposed with superheated steam and the oxidation process in which vaporized organics are decomposed with heated air. Experimental study in which waste TBP/n-dodecane (WTBP) containing uranium was used was conducted with the steam reforming system (SRS) to examine the distribution ratio of uranium in the system, the feasibility of treatment of WTBP and the effect of treatment with SRS on the volume reduction of WTBP. The results of these studies are as follows: (1) Most of uranium compounds in WTBP are separated from organics in GP. (2) Only the solid waste remained in GP is the radioactive secondary waste from the treatment of WTBP with SRS. (3) The maintenance operation of the equipments installed downstream of GP become easy to perform. (4) The volume of secondary solid wastes is very small because more than 99% of the WTBP were evaporated in GP. (5) It was estimated that the effect of treatment with SRS on the volume reduction of WTBP is 30 times more than that of pyrolysis method. These results show that SRS can achieve high volume reduction of WTBP.
Sone, Tomoyuki; Nonaka, Kazuharu; Sasaki, Toshiki; Yamaguchi, Hiromi
JAEA-Technology 2007-063, 42 Pages, 2008/01
JAEA-Technology-2007-063.pdf:2.17MB
Steam reforming method has been developed for the treatment of organic wastes which are not suitable materials (tributyl phosphate, halogenated oil) for the incineration due to large quantities of secondary wastes generation. Process demonstration tests were conducted with the demonstration scale steam reforming system to examine the feasibility of treatment of simulated waste solvent (TBP and n-dodecane mixture) and simulated waste oils (halogenated oils and mineral oil mixture). These tests were also conducted to optimize the process conditions. The results of these studies are as follows: (1)More than 98wt% of the simulated wastes were evaporated in the gasification process. Solid residues removed from the gasification process as secondary wastes were inorganic compounds. (2)While the simulated waste oils were treated, the stacking of the filter is reduced by increasing the feed rate of steam from 1.5 kg/h to 3.0 kg/h. (3)Most of phosphoric acids produced by thermal decomposition of TBP were vaporized in the gasification process at 600
650
C. This result shows that volume of radioactive secondary waste can be effectively reduced.
Sasaki, Toshiki; Sone, Tomoyuki; Nonaka, Kazuharu; Yamaguchi, Hiromi
no journal, ,
no abstracts in English
Sone, Tomoyuki; Nonaka, Kazuharu; Sasaki, Toshiki; Yamaguchi, Hiromi
no journal, ,
no abstracts in English
Osugi, Takeshi; Nakashio, Nobuyuki; Mimura, Ryuji; Nonaka, Kazuharu; Nakanishi, Yoshiki; Okoshi, Minoru; Tokizawa, Takayuki; Nakayama, Shinichi; Kimura, Takeshi*
no journal, ,
To reduce volume of wastes that consisted of plants and soil generated from decontamination works on farmland, we have produced a pilot-scale pyrolysis furnace by rotary kiln type and had some heat-treatment tests. In this reports, we shows some results of the tests on two kinds of paddy soils in Iitate-village.