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Journal Articles

Development of glass melting process for LLW at the research project commissioned by the Ministry of Economy, Trade and Industry

Fukui, Toshiki*; Maki, Takashi*; Miura, Nobuyuki; Tsukada, Takeshi*

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(2), p.169 - 173, 2016/12

The basic research programs for the next generation vitrification technology, which are commissioned project from Ministry of Economy, Trade and Industry of Japan, have been implemented from 2014 until 2018 for developing the advanced vitrification technology of low level wastes and high level liquid wastes.

Journal Articles

High-temperature X-ray imaging study of simulated high-level waste glass melt

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

Denki Kagaku Oyobi Kogyo Butsuri Kagaku, 81(7), p.543 - 546, 2013/07

 Times Cited Count:5 Percentile:14.87(Electrochemistry)

The molten state of simulated high-level waste glass and the behavior of ruthenium element in the melt were investigated by using synchrotron radiation based X-ray imaging technique. Melting, generating and moving of bubbles, condensation and sedimentation of ruthenium element were observed dynamically in continuous 12-bit gray-scale images from the CCD camera. X-ray intensity was obtained easily by digitizing gray-scale values in the image. The existence of ruthenium element is emphasized as a black color in the CCD image at X-ray energy higher than the Ru K-absorption edge. Position sensitive imaging X-ray absorption fine structure (XAFS) measurement was also performed to clarify the chemical state of ruthenium element in the melt.

Journal Articles

High-temperature X-ray imaging study of simulated high-level waste glass melt

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

Proceedings of 4th Asian Conference on Molten Salt Chemistry and Technology & 44th Symposium on Molten Salt Chemistry, Japan, p.47 - 52, 2012/09

The molten state of the simulated high-level waste glass and the behavior of ruthenium element in the melt were investigated by using synchrotron radiation based X-ray imaging technique. Melting, generating and moving of bubbles, condensation and sedimentation of ruthenium element were observed dynamically in continuous 12-bit gray-scale images from the CCD camera. The existence of ruthenium in the X-ray CCD image was emphasized over the energy of Ru K-absorption edge. X-ray intensity was obtained easily by digitalizing gray-scale values in the image. Position sensitive imaging X-ray absorption fine structure (XAFS) measurement was performed to clarify the chemical state of ruthenium element in the melt.

Journal Articles

Synchrotron radiation-based X-ray imaging study of ruthenium in simulated high-level waste glass

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Shiwaku, Hideaki; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; Nomura, Masaharu*

Nihon Genshiryoku Gakkai Wabun Rombunshi, 11(2), p.127 - 132, 2012/06

Distribution and the chemical state of Ru element in the simulated high-level waste glass were examined by using the synchrotron radiation based X-ray imaging technique. In this technique, a direct X-ray CCD camera is used in place of an ion chamber. Position sensitive X-ray absorption spectra were obtained by analyzing gray scale in images of the X-ray CCD camera. At first, we measured a test sample containing RuO$$_2$$ and Ru metal powder. We successfully obtained information on the Ru distribution in the sample. In addition, the chemical state (oxide or metal ?) of each small Ru-rich spot was evaluated by the corresponding position sensitive XAFS spectrum. The imaging XAFS technique was applied to some simulated high-level waste glass samples. The Ru distribution of the glass sample and their chemical state were confirmed by image analyses. It can be seen that Ru element scattered in the glass sample exists as oxide RuO$$_2$$.

JAEA Reports

Application of pervaporation to IS process (Joint research)

Kanagawa, Akihiro*; Iwatsuki, Jin; Tanaka, Nobuyuki; Onuki, Kaoru; Fukui, Hiroshi*; Nishibayashi, Toshiki*

JAEA-Technology 2007-061, 32 Pages, 2007/12

JAEA-Technology-2007-061.pdf:21.03MB

Separation of hydrogen iodide from HIx solution (HI-I$$_{2}$$-H$$_{2}$$O mixture) is one of the technical issues in the development of thermochemical IS process. Application of pervaporation (PV) to the concentration of HIx solution in the IS process pilot test plant was discussed from the viewpoints of process heat mass balance, conceptual design of the apparatus, and the corrosion resistance of the membrane module. Compared with the electro-electrodialysis system, the PV system enables the downsizing of apparatus by using hollow fiber membranes, although it does not improve the thermal efficiency of IS process. Immersion tests of commercially available Nafion hollow fiber membrane module in the HIx solution at 100$$^{circ}$$C indicated the necessity of improving the corrosion resistance of bundle materials.

Journal Articles

Vitrification of high-level radioactive waste by phosphate-type glass

Amamoto, Ippei; Myochin, Munetaka; Fukui, Toshiki*

New Glass, 22(2), p.21 - 26, 2007/06

As the electrolyte [LiCl-KCl] used in the pyrochemical reprocessing process by the electrorefining method will likely be contaminated by the accumulation of various fission products [FPs] after prolonged electrolytic operation, some measures, e.g., its replacement by a virgin electrolyte, etc. are necessary. The constant replacement of electrolyte, however, could lead to the generation of enormous amount of high level radioactive waste [HLW] because the spent electrolyte is a waste salt and is classified as HLW. From the viewpoints of environmental load reduction and economical improvement, it is desirable to have the spent electrolyte purified for recycling by removing its FPs. The FPs precipitation method by converting FPs to insoluble compounds such as phosphates could be one of the potential techniques to remove FPs. Subsequently, it is necessary to immobilise FPs precipitates by vitrification or some other methods. The possibility and potential advantages of the vitrification of FPs phosphates using the iron phosphate glass is introduced in this paper. At the same time, comparisons are made with the borosilicate immobilisation method.

Journal Articles

Effects of basicity and FeO concentration on the retention of $$^{137}$$Cs and $$^{60}$$Co in slag made from non-metallic radioactive wastes

Nakashima, Mikio; Nakashio, Nobuyuki; Kameo, Yutaka; Fukui, Toshiki*; Isobe, Motoyasu*; Otake, Atsushi*; Wakui, Takuji*; Hirabayashi, Takakuni*

Radiochimica Acta, 91(1), p.45 - 51, 2003/01

 Times Cited Count:2 Percentile:19.75(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

Characterization of solidified products yielded by plasma melting treatment of simulated non-metallic radioactive wastes

Nakashima, Mikio; Fukui, Toshiki*; Nakashio, Nobuyuki; Isobe, Motoyasu*; Otake, Atsushi*; Wakui, Takuji*; Hirabayashi, Takakuni*

Journal of Nuclear Science and Technology, 39(6), p.687 - 694, 2002/06

 Times Cited Count:13 Percentile:65.26(Nuclear Science & Technology)

no abstracts in English

JAEA Reports

None

; Obayashi, Hiroshi; ; *; Fukui, Toshiki*; Arai, Kazuhiro*

JNC TJ6410 2002-013, 38 Pages, 2002/02

JNC-TJ6410-2002-013.pdf:1.18MB

no abstracts in English

JAEA Reports

Study on melting coditions of radioactive miscellaneous solid waste (Contract research)

Fukui, Toshiki; Nakashio, Nobuyuki; Isobe, Motoyasu; Otake, Atsushi*; Wakui, Takuji*; Hirabayashi, Takakuni*; Nakashima, Mikio

JAERI-Review 2000-033, 82 Pages, 2001/02

JAERI-Review-2000-033.pdf:2.61MB

no abstracts in English

JAEA Reports

Melting behavior of low-level radioactive miscellaneous solid waste and characteristics of solidified products (Contract research)

Nakashio, Nobuyuki; Isobe, Motoyasu; Wakui, Takuji*; Iwata, Keiji*; Kibayashi, Tatsuyuki*; Kanazawa, Katsuo; Fukui, Toshiki; Otake, Atsushi*; Nakashima, Mikio; Hirabayashi, Takakuni*

JAERI-Research 2001-001, 19 Pages, 2001/02

JAERI-Research-2001-001.pdf:1.29MB

no abstracts in English

Journal Articles

Study on plasma melting of miscellaneous low-level radioactive waste

Nakashio, Nobuyuki; Wakui, Takuji*; Otake, Atsushi*; Nakashima, Mikio; Fukui, Toshiki*; Isobe, Motoyasu*

Proceedings of 8th International Conference on Radioactive Waste Management and Environmental Remediation (ICEM '01) (CD-ROM), 4 Pages, 2001/00

no abstracts in English

Journal Articles

Study on treatment of miscellaneous solid waste by plasmas melting; Melting characteristics of plasma heating method

Fukui, Toshiki; Nakashio, Nobuyuki; Isobe, Motoyasu; Otake, Atsushi*; Wakui, Takuji*; Nakashima, Mikio; Hirabayashi, Takakuni*

Dai-7-Kai Doryoku Enerugi Gijutsu Shimpojiumu Koen Rombunshu (00-11), p.356 - 359, 2000/00

no abstracts in English

Oral presentation

Development of a long-life vitrification melter

Kato, Junya; Miyauchi, Atsushi; Aoshima, Atsushi; Shiotsuki, Masao; Yamashita, Teruo; Nakajima, Masayoshi; Morikawa, Yo; Miura, Akihiko; Fukui, Toshiki*; Yamasaki, Akito*; et al.

no journal, , 

no abstracts in English

Oral presentation

Feasibility study on a long-life vitrification melter

Yamashita, Teruo; Miura, Akihiko; Kato, Junya; Shiotsuki, Masao; Ono, Isamu*; Fukui, Toshiki*; Yamasaki, Akito*; Matsumoto, Shiro*

no journal, , 

The objective of this development is to extend vitrification melter life-time to reduce burden of the high level radioactive waste management by applying advanced technologies. The candidate concepts of the long-life melter were studied with evaluation of adopted important advanced technologies such as skull layer conditions and the commutative electrode structure. It was concluded that such technology has a potential to extend melter life as 20 years even in the preliminary studies. Based on the obtained results, after the following fiscal year, evaluation of each component, small scale melter examination, and development and evaluation of simulation tool are carried out.

Oral presentation

Closed cycle and continuous operation by a thermo-chemical water-splitting IS process

Kubo, Shinji; Ohashi, Hirofumi; Kanagawa, Akihiro; Kasahara, Seiji; Imai, Yoshiyuki; Fukui, Hiroshi*; Nishibayashi, Toshiki*; Shimazaki, Masanori*; Miyashita, Reiko*; Tago, Yasuhiro*; et al.

no journal, , 

For a stable hydrogen production, essential problems with the closed-cycle operation are declared, and the cycle can ensure these are retained in a steady state in case the H$$_{2}$$ production rate, O$$_{2}$$ production rate and H$$_{2}$$O supply rate have equivalent values. Process control methods used to maintain the mass balance of the process were devised, involving the installation of accumulators for the total system, techniques to maintain the Bunsen reaction composition and so on. For the plant operation, both controlled and manipulated variables were determined, while computer simulation and the bench scale H$$_{2}$$ production test were used to confirm control methods. For closed cycle operation for water splitting driven by helium gas heat, the method is discussed to allocate heat for the O$$_{2}$$ and H$$_{2}$$ production sections in strict proportion. Finally, the use of computer simulation for the O$$_{2}$$ production system allowed the key to maintaining heat balance within a cascade heat absorption system to be confirmed.

Oral presentation

Chemical state analysis of metals in imitative glasses by using Imaging XAFS technique

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Minato, Kazuo; Shiwaku, Hideaki; Komamine, Satoshi*; Fukui, Toshiki*; Nitani, Hiroaki*; Nomura, Masaharu*

no journal, , 

Chemical state analysis of Ru element scattered in an imitative glass matrix was performed by using the Imaging XAFS technique. Information on distribution of Ru element in the matrix was obtained from contrast values of CCD images before and after the Ru K-absorption edge. It is confirmed that the feature of the distributed element can be examined by getting XAFS spectra from the contrast information. We can get two kinds of XAFS spectra corresponding to Ru metal and oxide separately in the Imaging XAFS analysis.

Oral presentation

Synchrotron radiation based X-ray imaging study of simulated high-level waste glass

Okamoto, Yoshihiro; Nakada, Masami; Akabori, Mitsuo; Minato, Kazuo; Shiwaku, Hideaki; Yaita, Tsuyoshi; Komamine, Satoshi*; Fukui, Toshiki*; Ochi, Eiji*; Nitani, Hiroaki*; et al.

no journal, , 

Distribution and the chemical state of Ru element in the simulated high-level waste glass were examined by using the synchrotron radiation based X-ray imaging technique. In this technique, a direct X-ray CCD camera is used in place of an ion chamber. Position sensitive X-ray absorption spectra were obtained by analyzing gray scale in images of the X-ray CCD camera. It can be seen that Ru element scattered in the glass sample exists as oxide RuO$$_2$$.

Oral presentation

Analyses on the insoluble residue generated at Rokkasho Reprocessing Plant, 2; Thermal and microstructural analyses

Takano, Masahide; Yamagishi, Isao; Akabori, Mitsuo; Minato, Kazuo; Fukui, Toshiki*; Yoshioka, Masahiro*

no journal, , 

no abstracts in English

Oral presentation

Properties of insoluble residue generated at Rokkasho Reprocessing Plant, 5; Oxidation behavior of insoluble residue

Takano, Masahide; Yamagishi, Isao; Akabori, Mitsuo; Minato, Kazuo; Yoshioka, Masahiro*; Ochi, Eiji*; Fukui, Toshiki*; Komamine, Satoshi*

no journal, , 

no abstracts in English

36 (Records 1-20 displayed on this page)