Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Washiya, Tadahiro; Yano, Kimihiko; Kaji, Naoya; Yamada, Seiya*; Kamiya, Masayoshi
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 7 Pages, 2015/05
On March 11, 2011, a severe nuclear accident occurred at Tokyo Electric Power Company (TEPCO)'s Fukushima Daiichi Nuclear Power Plant (hereinafter called as F1). After the accident, the Council for the Decommissioning was established, mainly by the government and TEPCO, and a road map for the F1 decommissioning was drawn up. In the road map, the fuel debris removal from the reactors is scheduled to launch around 2020. In this study, the characteristics and technological issues of each potential treatment scenario were extracted, and the scenarios were prioritized in advance of formal evaluations in the future. The preliminary evaluation results show that long term storage and direct disposal have more positive aspects in terms of economic efficiency and radioactive waste generation. On the other hand, stabilizing processing, aqueous processing, and pyrochemical processing have been estimated to have more disadvantages in such aspects.
-based simulated fuel debris in nitric acidIkeuchi, Hirotomo; Ishihara, Miho; Yano, Kimihiko; Kaji, Naoya; Nakajima, Yasuo; Washiya, Tadahiro
Journal of Nuclear Science and Technology, 51(7-8), p.996 - 1005, 2014/07
Times Cited Count：7 Percentile：49.88(Nuclear Science & Technology)Ikeuchi, Hirotomo; Kondo, Yoshikazu*; Noguchi, Yoshihiro*; Yano, Kimihiko; Kaji, Naoya; Washiya, Tadahiro
Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.1349 - 1356, 2013/09
Yano, Kimihiko; Kitagaki, Toru; Ikeuchi, Hirotomo; Wakui, Ryohei; Higuchi, Hidetoshi; Kaji, Naoya; Koizumi, Kenji; Washiya, Tadahiro
Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.1554 - 1559, 2013/09
Nakahara, Masaumi; Kaji, Naoya; Yano, Kimihiko; Shibata, Atsuhiro; Takeuchi, Masayuki; Okano, Masanori; Kuno, Takehiko
Journal of Chemical Engineering of Japan, 46(1), p.56 - 62, 2013/01
Times Cited Count：1 Percentile：6.49(Engineering, Chemical)The influence of HNO
concentration in the solution on the formation of CsPu(NO)
was evaluated in the U crystallization process. The solubility of CsPu(NO) in a uranyl nitrate solution was found to decrease with increasing HNO concentration in the solution. In the U crystallization experiments with the dissolver solution of irradiated fast reactor fuel, CsPu(NO) formed with 6.5 mol/dm
HNO concentration in the mother liquor, and the decontamination factor of Cs for the uranyl nitrate hexahydrate crystals was low. Meanwhile, CsPu(NO) did not precipitate with uranyl nitrate hexahydrate crystals under the condition of 4.0 mol/dm HNO concentration in the mother liquor, and Cs could be separated from the uranyl nitrate hexahydrate crystals.
Nakahara, Masaumi; Kaji, Naoya; Nomura, Kazunori
JAEA-Research 2012-009, 15 Pages, 2012/06
JAEA-Research-2012-009.pdf:6.37MB
In terms of preventing the formation of Pu and Cs compound, Cs in the feed solution should decrease in the U crystallization process. In order to separate Cs contained within irradiated nuclear fuel, the immersion experiments were carried out with the pure water and diluted HNO solution. The elusion ratio of Cs within the powdered fuel in the pure water and 0.1 mol/dm HNO solution after 67 h was 33.8 and 38.3%, respectively. The experimental results suggest a possible beneficial effect of Cs elusion by immersion of the powdered fuel in the pure water and diluted HNO solution before the fuel dissolution process.
Sano, Yuichi; Kaji, Naoya; Shibata, Atsuhiro; Takeuchi, Masayuki; Washiya, Tadahiro
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 7 Pages, 2011/12
Inoue, Naoko; Kaji, Naoya; Suda, Kazunori; Kawakubo, Yoko; Suzuki, Mitsutoshi; Koyama, Tomozo; Kuno, Yusuke; Senzaki, Masao
Proceedings of INMM 51st Annual Meeting (CD-ROM), 10 Pages, 2010/07
Shibata, Atsuhiro; Kaji, Naoya; Nakahara, Masaumi; Yano, Kimihiko; Tayama, Toshimitsu; Nakamura, Kazuhito; Washiya, Tadahiro; Myochin, Munetaka; Chikazawa, Takahiro*; Kikuchi, Toshiaki*
Proceedings of International Conference on Advanced Nuclear Fuel Cycle; Sustainable Options & Industrial Perspectives (Global 2009) (CD-ROM), p.151 - 157, 2009/09
As a part of FaCT project, Japan Atomic Energy Agency has been developing a U crystallization process for advanced aqueous reprocessing technology in collaboration with Mitsubishi Materials Corporation. We have carried out experimental studies and obtained fundamental data. Continuous operation tests were also carried out by an engineering-scale crystallizer to confirm productivity of the equipment and to investigate non-steady state conditions. The requirements for the U crystallization process in the FaCT project could be achieved except DF of Cs. More detail investigation is under way to settle the process condition without Pu-Cs double salt formation.
Nomura, Kazunori; Hinai, Hiroshi; Nakahara, Masaumi; Kaji, Naoya; Kamiya, Masayoshi; Oyama, Koichi; Sano, Yuichi; Washiya, Tadahiro; Komaki, Jun
Proceedings of 3rd International ATALANTE Conference (ATALANTE 2008) (CD-ROM), 5 Pages, 2008/05
Kaji, Naoya; Nakahara, Masaumi; Nakamura, Kazuhito; Shibata, Atsuhiro; Tomita, Yutaka; Washiya, Tadahiro; Kitajima, Takafumi; Koizumi, Tsutomu
no journal, ,
Solubility obtained from the latest crystallization tests using irradiated fuel and the tests implemented before using U or Pu/U are compared with the data showed by Hart. Based on the result, availability of the data to estimate crystallization ratio is considered.
Kaji, Naoya; Nomura, Kazunori; Sano, Yuichi; Koizumi, Tsutomu
no journal, ,
Advanced aqueous reprocessing is the technology that JAEA is developing as a part of Fast Reactor Cycle Technology Development Project (FaCT). Radioactive liquid waste polarization is one of the concepts introduced to the advanced aqueous reprocessing. In this concept, waste solutions are to be concentrated enough to just be divided to two categories of high level and very low level. It will be achieved by decreasing amount of sodium salt waste drastically and decomposing excess nitric acid. One of the main sources of sodium salt waste in the conventional PUREX is the solvent washing process with sodium carbonate. Salt-free technology brings alternative solvent washing method that does not produce the sodium salt waste. The outline and the current status of the development of this technology will be reported.
Kaji, Naoya; Nakamura, Kazuhito; Nomura, Kazunori; Shibata, Atsuhiro; Yano, Kimihiko; Washiya, Tadahiro; Kitajima, Takafumi; Koizumi, Tsutomu
no journal, ,
For the purpose of obtaining DFs of the short-life FPs by 
analysis in the hot experiment, fundamental test of crystallization process was carried out using Fast Experimental Reactor "JOYO" irradiated fuel. In this experiment, DFs of nuclides analyzed by analysis except Cs (Such as Ru-106, Ce-144, Pr-144) and Pu were evaluated to be about 100. It was suggested that there is the condition in which Pu-Cs double salt does not be formed, although DF of Cs had been very low in the past experiments because of forming Pu-Cs double salt.
Yamamoto, Kohei; Kaji, Naoya; Morimoto, Kazuyuki; Obu, Tomoyuki; Sano, Yuichi; Kashimura, Takao
no journal, ,
no abstracts in English
Kaji, Naoya; Kamiya, Masayoshi; Koma, Yoshikazu; Koizumi, Tsutomu; Koyama, Tomozo; Aoki, Kazuo*; Yamada, Seiya*
no journal, ,
no abstracts in English
Kamiya, Masayoshi; Kaji, Naoya; Koyama, Tomozo; Aoki, Kazuo*; Yamada, Seiya*
no journal, ,
It is shown in this presentation that the outline "development of actinides co-extraction system with direct extraction process using supercritical fluid" and future schedule.
Kaji, Naoya; Kamiya, Masayoshi; Takahatake, Yoko; Oyama, Koichi; Miura, Sachiko; Koyama, Tomozo; Aoki, Kazuo*; Yamada, Seiya*
no journal, ,
A battery of tests using MOX fuel were performed for development of actinides co-extraction system with direct extraction process using supercritical fluid. The condition that was set up based on consideration of the results of the tests under ordinary pressure, and then was made fine adjusted based on the tests with supercritical fruid. As a result, U, Pu and Am were extracted simultaneously. Comparative test confirmed that U, Pu and Am could be also extracted simultaneously with dodecane as a diluent. While the extraction test of unirradiated MOX fuel with simulated FP, U, Pu was extracted with U and Am, and the Pu residue, that was found at the extraction test of irradiated fuel, was not found. As the result of scrubbing and stripping test, it was showed that traditional extraction process design method could be applied to design scrubbing and stripping process with supercritical fluid.
Koyama, Tomozo; Kamiya, Masayoshi; Kaji, Naoya; Aoki, Kazuo*; Yamada, Seiya*
no journal, ,
The summary of development of actinides co-extraction system with direct extraction process using supercritical fluid which was started at 2005 is reported here.
Kamiya, Masayoshi; Kaji, Naoya; Koyama, Tomozo; Aoki, Kazuo*; Yamada, Seiya*
no journal, ,
Main process of actinides co-extraction system with direct extraction process using supercritical fluid was designed. The improvement effect of the cost performance was small because multiple lines were needed about main process. But we got the evaluation result that it is possible to reduce substantially about waste liquid treatment. Based on the result, the improvement which uses supercritical fluid for partitioning was gathered.
