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Sakai, Akihiro
Dai-33-Kai Genshiryoku Shisetsu Dekomisshoningu Gijutsu Koza Tekisuto, p.31 - 63, 2023/02
The Japan Atomic Energy Agency (JAEA) is promoting the project for concrete-vault disposal and landfill-type disposal of radioactive waste generated from research facilities, etc. This report introduces current status of technical development for JAEA's disposal project as following items; (1) kinds of research facilities and characteristics of radioactivity inventory of the waste, (2) the structures of the disposal facilities which JAEA conceptually designed, (3) development of waste acceptance criteria for major radioactive waste for the JAEA disposal facilities, (4) the concept of the criteria for disposal of uranium bearing waste, that has been established in 2021.
Yasuda, Hiroshi*; Fumoto, Hiromichi*; Saito, Tatsuo
Nihon Genshiryoku Gakkai-Shi ATOMO
, 63(8), p.610 - 614, 2021/08
Regarding the handling of uranium bearing waste, which is contaminated with uranium, which is a naturally occurring radionuclide, and its descendant nuclides, in recent years, the Japan Nuclear Regulatory Commission, etc. have been carefully and actively deliberated based on the knowledge of natural science and safety engineering. It was carried out, and as of March 2021, a certain policy has been shown. On the other hand, when disposing of uranium waste, which may cause dose exposure to future generations, the authors consider not only the science and engineering perspectives that have been conducted so far, but also the humanities and social science perspectives. We have been discussing with experts in related fields, thinking that it is necessary. In this report, we will introduce the background that brought about such an idea and the direction of future discussions.
Task Force on Writing Textbook of Nuclear Fuel Materials
JAEA-Review 2020-007, 165 Pages, 2020/07
JAEA-Review-2020-007.pdf:6.63MB
The present textbook was written by Task Force on Writing Textbook of Nuclear Fuel Materials at the Nuclear Science Research Institute in order to improve technological abilities of engineers and researchers who handle nuclear fuel materials. The taskforce consists of young and middle class engineers each having certification for chief engineer of nuclear fuel. The present textbook mainly deals with uranium and plutonium, and shows their nuclear properties, physical and chemical properties, and radiation effects on materials and human body. It also presents basic matters for safety handling of nuclear fuel materials, such as handling of nuclear fuel materials with hood and glovebox, important points in storage and transportation of nuclear fuel materials, radioactive waste management, radiation safety management, and emergency management. Furthermore, incident cases at domestic and foreign nuclear fuel materials facilities are compiled to learn from the past.
Yokoyama, Kaoru; Ohashi, Yusuke
Annals of Nuclear Energy, 141, p.107299_1 - 107299_5, 2020/06
Times Cited Count：6 Percentile：60.71(Nuclear Science & Technology)A large amount of general steel waste is generated during decommissioning and dismantling of nuclear facilities. Very low-contaminated radioactive waste, whose radioactivity is below clearance level, generated from the demolition process may be reused for general use. We examined the feasibility of the clearance verification system for uranium waste. The relative error of uranium determination was within 30% for 1 g of uranium when measuring steel materials (angle bar, channel steel, pipe steel, square steel tube, fragments of metal tube).
Saito, Tatsuo; Kobayashi, Shinichi*; Zaitsu, Tomohisa*; Shimo, Michikuni*; Fumoto, Hiromichi*
Hoken Butsuri (Internet), 55(2), p.86 - 91, 2020/06
Safety cases for disposal of uranium bearing waste and NORM with uranium has not yet been fully developed in Japan, because of safety assessment of extraordinary long timespan and uncertainty in unexpected incidents with uncompleted radon impact evaluation measures arising from uranium waste disposal facility in far future. Our task group of radiation protection for wastes with natural radioactive nuclides studied some safety cases with disposal of uranium bearing waste and NORM in terms of nuclides, U-235, U-238 and their progenies, and comprehensively discussed the current state of their disposal in comparison to the ideas of international organizations such as ICRP and IAEA. We developed our ideas for long term uncertainty and radon with the knowledge of experts in each related area of direction, repeating discussions, focusing out the orientation of each directions, and outlined the recommendations with our suggestions of solving important issues in the future to be addressed.
Umezawa, Katsuhiro; Morimoto, Yasuyuki; Nakayama, Takuya; Nakagiri, Toshio
Proceedings of 27th International Conference on Nuclear Engineering (ICONE-27) (Internet), 6 Pages, 2019/05
In December 2016, the Ningyo-toge Environmental Engineering Center of Japan Atomic Energy Agency (JAEA Ningyo-toge) announced new concept of "Uranium and Environmental Research Platform". As part of the concept, uranium waste engineering research are now undergoing. The objective of the research is to establish the processing technology for safely and reasonable disposal of uranium waste. In particular, estimation of the amount of uranium and harmful substances and development of technologies to reduce their concentration in the waste to the permissive level for the disposal in shallow ground disposal are needed. We are now developing the technologies to reduce the concentration of uranium and harmful substances shown below. (1) Survey on uranium inventory. Uranium waste is now stored in 10-odd thousands of 200 L drums. We are surveying amount and chemical form of uranium in the drums. (2) Development of decontamination technology of metal and concrete waste. We are investigating decontamination methods for metals and concrete contaminated with uranium. (3) Development of technologies to remove, detoxify and fix the harmful substances. We are surveying the types and amounts of harmful substances in waste. In addition, we are investigating the method to remove, detoxify, and fix harmful substances. (4) Measurement technology of uranium radioactivity. We are investigating and examining ways to improve the quantitative accuracy of measurement and shorten the measurement time. (5) Development of uranium removal technology from sludge. We are investigating new processing method to remove uranium from sludge which is applicable for several kind of sludge. The results of these technological developments and environmental research will be reflected to "small-scale field test" and "disposal demonstration test" which are planned for demonstration of the uranium waste disposal technology.
-UO
-CO
system and integration with JAEA's thermodynamic database for geochemical calculationsKitamura, Akira
JAEA-Data/Code 2018-018, 103 Pages, 2019/03
JAEA-Data-Code-2018-018.pdf:5.66MB
JAEA-Data-Code-2018-018-appendix1(DVD-ROM).zip:0.14MBJAEA-Data-Code-2018-018-appendix2(DVD-ROM).zip:0.15MBJAEA-Data-Code-2018-018-appendix3(DVD-ROM).zip:0.19MB
The latest available thermodynamic data were critically reviewed and the selected values were included into the JAEA-TDB for performance assessment of geological disposal of high-level radioactive and TRU wastes. This critical review specifically addressed thermodynamic data for (1) a zirconium-hydroxide system through comparison of thermodynamic data selected by the Nuclear Energy Agency within the Organisation for Economic Co-operation and Development (OECD/NEA), (2) complexation of metal ions with isosaccharinic acid based on the latest review papers. Furthermore, the author performed (3) tentative selection of thermodynamic data on ternary complexes among alkaline-earth metal, uranyl and carbonate ions, and (4) integration with the latest version of JAEA's thermodynamic database for geochemical calculations. The internal consistency of the selected data was checked by the author. Text files of the updated and integrated thermodynamic database have been prepared for geochemical calculation programs of PHREEQC and Geochemist's Workbench.
Nagano, Tetsushi; Naganawa, Hirochika; Suzuki, Hideya; Toshimitsu, Masaaki*; Mitamura, Hisayoshi*; Yanase, Nobuyuki*; Grambow, B.
Analytical Sciences, 34(9), p.1099 - 1102, 2018/09
Times Cited Count：12 Percentile：45.99(Chemistry, Analytical)A previously reported emulsion flow (EF) extraction system does not include a device for refining used solvent. Therefore, the processing of large quantities of wastewater by using the EF extractor alone could lead to the accumulation of wastewater components into the solvent and diminished extraction performance. In the present study, we have developed a solvent-washing-type EF system, which is equipped with a unit for washing used solvent to prevent accumulation, and successfully applied it for treating uranium-containing wastewater.
Sakai, Akihiro; Hasegawa, Makoto; Sakamoto, Yoshiaki; Nakatani, Takayoshi
Proceedings of International Conference on the Safety of Radioactive Waste Management (Internet), p.98_1 - 98_4, 2016/11
The radioactivity of uranium-bearing waste contaminated by refined uranium increases with the production of its progeny on a long-term timescale. Therefore, the long-term safety concept of the near surface disposal of uranium-bearing waste is very important. The Japan Atomic Energy Agency (JAEA) examines disposal safety by controlling the average uranium radioactivity concentration in each section of disposal facility and performing safety assessment for very conservative assumptions.
Komeda, Masao; Ozu, Akira; Haruyama, Mitsuo; Takase, Misao*; Kureta, Masatoshi; Nakatsuka, Yoshiaki; Zaima, Naoki; Nakashima, Shinichi; Otsuka, Yoshimasa
Proceedings of INMM 55th Annual Meeting (Internet), 9 Pages, 2014/07
We have researched and developed the FNDI method for a long time through experiments in NUCEF in JAEA Tokai. Referred from the pilot machine, we designed a demonstrator, called as JAWAS-N, for applying to non-destructive assay tools for uranium waste drums in JAEA Ningyo. In this paper, we present the modeling and the simulations concerning JAWAS-N's characteristics, and discuss for practical use compared analytical results with obtained some experimental data.
Uchiyama, Gunzo; Asakura, Toshihide; Hotoku, Shinobu; Fujine, Sachio
Solvent Extr. Ion Exch., 16(5), p.1191 - 1213, 1998/00
Times Cited Count：14 Percentile：57.75(Chemistry, Multidisciplinary)no abstracts in English
Ogawa, Toru
Shometsu Shori Kenkyu No Genjo; Atarashii Genshiryoku Gijutsu No Kanosei O Motomete, 0, p.117 - 124, 1994/08
no abstracts in English
Yanagisawa, Hiroshi; Takeshita, Isao; Nomura, Masayuki; ; Tsujino, Takeshi
Proc. of the CSNI Specialist Meeting on Safety and Risk Assessment in Fuel Cycle Facilities, p.461 - 470, 1991/00
no abstracts in English
; *; *;
Radioact.Waste Manage.Nucl.Fuel Cycle, 3(1), p.17 - 27, 1982/00
no abstracts in English
Kobayashi, Taishi*; Sasaki, Takayuki*; Kitamura, Akira
no journal, ,
The solubility of U(OH)
(am) was investigated in the presence of isosaccharinic acid (ISA) as a function of hydrogen ion concentration (pHc) and ISA concentration. The solubility in neutral pH region was independent of pHc, while those in alkaline pH region slightly increased with increasing pHc. The solubility was investigated as a function of ISA concentration and found to increase with a slope of approximately 2 with increasing ISA concentration. It was therefore suggested that U(OH)(ISA) and U(OH)
(ISA)
were the dominant U(IV)-ISA complexes, which were similar to those observed in Zr(IV)-ISA system. Complex formation constants were determined by the least square fitting analysis of the solubility data and the calculated solubility curve well reproduced the experimental data.
Saito, Tatsuo
no journal, ,
Task Group discussed the issues regarding the radiation protection of waste containing natural radionuclides from the perspective of radiation protection. The exposure of the disposal of uranium generated from uranium treating facilities is in planned exposure situation, but may become a source of existing exposure when the institutional control of the repository is over. Uranium disposal is insignificant as the source of exposure to future generations when a disposal plan of no more than 1 Bq/g or 1 mSv/year is established before the institutional control is finished. If only uranium that can be disposed of within the framework of planned exposure can be disposed of, there may be legacy uranium. For future generations that inherit the existing exposure of uranium, it is necessary to consider what the present generation should do and how far it should fulfill its exposure assessment or reduction.
