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Journal Articles

Toward realizing near surface disposal of LLW generated from research facilities, etc.; Status of development for safety of the disposal by JAEA

Sakai, Akihiro; Kamei, Gento; Sakamoto, Yoshiaki

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 65(1), p.25 - 29, 2023/01

Currently, radioactive waste generated from research institutes, etc. is keeping in storage facilities without being disposed of. In order to solve this problem, the Japan Atomic Energy Agency (JAEA) is proceeding with the project for concrete-pit disposal and trench disposal of these waste. This paper introduces the characteristics of the waste and disposal facilities planned by the JAEA, as well as the status of development of the siting criteria for the disposal facility.

Journal Articles

Understanding of underground in the context of geological disposal

Kamei, Gento

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 24(1), P. 1, 2017/06

As a preface of the Journal of Nuclear Fuel Cycle and Environment, published by the Atomic Energy Society of Japan, importance of understanding of underground in the context of geological disposal is related.

Journal Articles

Report on the planed session by the NUCE in 2016 AESJ Fall Meeting, "How is the ability of the waste form glass?; Current status of the performance assessment of the waste form glass in the geological disposal system"

Kamei, Gento

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(2), p.201 - 202, 2016/12

This paper reports an overview of a planed session, "How is the ability of the waste form glass?; Current status of the performance assessment of the waste form glass in the geological disposal system", held by the NUCE in 2016 AESJ Fall Meeting. Five panelists respectively introduced case studies and/or aspects from the view point of performance assessment, current status in the world including Japan, basic sciences and computation sciences.

Journal Articles

An Outline of technologies of radioactive waste processing and disposal

Kamei, Gento

Genshiryoku Bakkuendo Kenkyu (CD-ROM), 23(1), p.75 - 77, 2016/06

After the Fukushima accident, concerns to nuclear power have been growing in Japanese society. Deriving from the issue, radioactive waste processing and disposal, including geological isolation, has been regarding as a social important problem. In consideration to such social trends, the author present fundamental information about radioactive waste generation, processing technology, disposal system (especially for high-level radioactive waste) based on the waste properties, and its safety assessment.

Journal Articles

Introduction to radioactive waste; Management of radioactive waste from operation and decommissioning of nuclear and other facilities, 7; Safety assessment of geological disposal system

Shibata, Masahiro; Kamei, Gento

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 57(4), p.271 - 275, 2015/04

no abstracts in English

JAEA Reports

Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage, 3; Progress report on NUMO-JAEA collaborative research in FY2013 (Joint research)

Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Kitamura, Akira; Yoshikawa, Hideki; Oda, Chie; Ishidera, Takamitsu; et al.

JAEA-Research 2014-030, 457 Pages, 2015/03

JAEA-Research-2014-030.pdf:199.23MB

JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and post-closure performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, based on some examples of developing method of hydro-geological structure model, acquired knowledge are arranged using the tree diagram, and model uncertainty and its influence on the evaluation items were discussed. With regard to (2) study on scenario development, the developed approach for "defining conditions" has been reevaluated and improved from practical viewpoints. In addition, the uncertainty evaluation for the effect of use of cementitious material, as well as glass dissolution model, was conducted with analytical evaluation. With regard to (3) study on setting radionuclide migration parameters, based on survey of precedent procedures, multiple-approach for distribution coefficient of rocks was established, and the adequacy of the approach was confirmed though its application to sedimentary rock and granitic rock. Besides, an approach for solubility setting was developed including the procedure of selection of solubility limiting solid phase. The adequacy of the approach was confirmed though its application to key radionuclides.

JAEA Reports

Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage, 2; Progress report on NUMO-JAEA collaborative research in FY2012 (Joint research)

Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Hayano, Akira; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.

JAEA-Research 2013-037, 455 Pages, 2013/12

JAEA-Research-2013-037.pdf:42.0MB

Following FY2011, JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, the tree diagram of methodology of groundwater travel time has been extended for crystalline rock, in addition, tree diagram for sedimentary rock newly has been organized. With regard to (2) study on scenario development, the existing approach has been improved in terms of a practical task, and applied and tested for near field focusing on the buffer. In addition, the uncertainty of some important processes and its impact on safety functions are discussed though analysis. With regard to (3) study on setting radionuclide migration parameters, the approaches for parameter setting have been developed for sorption for rocks and solubility, and applied and tested through parameter setting exercises for key radionuclides.

Journal Articles

Thorium and americium solubilities in cement pore water containing superplasticiser compared with thermodynamic calculations

Kitamura, Akira; Fujiwara, Kenso; Mihara, Morihiro; Cowper, M.*; Kamei, Gento

Journal of Radioanalytical and Nuclear Chemistry, 298(1), p.485 - 493, 2013/10

 Times Cited Count:11 Percentile:64.36(Chemistry, Analytical)

Solubility of thorium and americium in pore water squeezed from a cement paste was investigated by a batch method from oversaturation. The ordinary Portland cement was mixed with deionised water to prepare a cement paste from which the pore water was squeezed following solidification. Another batch of pore water was collected by the same method except that a superplasticiser was added to the deionised water used to prepare the cement paste. The aim was to investigate an effect of superplasticiser on solubility of thorium and americium in the squeezed cement porewaters. The obtained solubility values in the two squeezed pore waters (with and without superplasticiser present) were similar. Thermodynamic calculations were performed with the JAEA-TDB thermodynamic database and compared with the experimental data to verify their applicability. This result showed that superplasticisers after mixing with the cement paste did not have a significant effect on solubility of thorium and americium, and the thermodynamic calculations were applicable in the present system. Size distribution of colloidal species of thorium and americium was also investigated.

JAEA Reports

Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage; Progress report on NUMO-JAEA collaborative research in FY2011 (Joint research)

Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Hayano, Akira; Mitsui, Seiichiro; Taniguchi, Naoki; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.

JAEA-Research 2012-032, 298 Pages, 2012/09

JAEA-Research-2012-032.pdf:33.68MB

JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation phase. The topics and the conducted research are follows; (1) Study on selection of host rock: in terms of hydraulic properties, items for assessing rock property, and assessment methodology of groundwater travel time has been organized with interaction from site investigation. (2) Study on development of scenario: the existing approach has been embodied, in addition, the phenomenological understanding regarding dissolution of and nuclide release from vitrified waste, corrosion of the overpack, long-term performance of the buffer are summarized. (3) Study on setting nuclide migration parameters: the approach for parameter setting has been improved for sorption and diffusion coefficient of buffer/rock, and applied and tested for parameter setting of key radionuclides. (4) Study on ensuring quality of knowledge: framework for ensuring quality of knowledge has been studied and examined aimed at the likely disposal facility condition.

JAEA Reports

Research and development for treatment and disposal technologies of TRU waste; JFY 2010 annual report

Kamei, Gento; Honda, Akira; Oda, Chie; Hirano, Fumio; Ichige, Satoru; Kurimoto, Yoshitaka; Hoshino, Seiichi; Akagi, Yosuke; Sato, Nobuyuki; Takahashi, Kuniaki; et al.

JAEA-Research 2012-010, 80 Pages, 2012/06

JAEA-Research-2012-010.pdf:7.45MB

Based on Japanese governmental policy and general scheme, research and development of geological disposal technology for TRU waste has been proceeding to improve reliability of the safety assessment of the co-locational disposal of TRU waste and of HLW, to expand the basement of generic safety assessment, and to develop the alternative technology to cope with the broad geologic environment of Japan. Japan Atomic Energy Agency is dealing with the assignments in the governmental generic scheme. We report here the progress of the studies at the end of H22 (2010) Japanese fiscal year and their products during the last 5 years. These include (1) evaluation of long-term mechanical stability in the near-field including development of a creep mode of rock and analyses of mechanical behavior of TRU waste repository, (2) performance assessment of the disposal system including cementitious material alteration, bentonite and hostrock alteration with alkaline solution and nitrate effect, and (3) alternative technology development including decomposition of nitrate.

JAEA Reports

Research and development for treatment and disposal technologies of TRU waste; JFY 2009 annual report

Kamei, Gento; Honda, Akira; Mihara, Morihiro; Oda, Chie; Ichige, Satoru; Kurimoto, Yoshitaka; Hoshino, Seiichi; Akagi, Yosuke; Sato, Nobuyuki; Murakami, Hiroshi*; et al.

JAEA-Research 2011-002, 82 Pages, 2011/03

JAEA-Research-2011-002.pdf:5.64MB

Based on Japanese governmental policy and general scheme, research and development of geological disposal technology for TRU waste has been proceeding to improve reliability of the safety assessment of the co-locational disposal of TRU waste and of HLW, to expand the basement of generic safety assessment, and to develop the alternative technology to cope with the broad geologic environment of Japan. Japan Atomic Energy Agency is dealing with the assignments in the governmental generic scheme. We report here the progress of the studies at the end of H20 (2008) Japanese fiscal year, which are (1) evaluation of long-term mechanical stability in the near-field including development of a creep mode of rock and analyses of mechanical behavior of TRU waste repository, (2) performance assessment of the disposal system including data acquisition and preparation on radionuclides migration, cementitious material alteration, bentonite and hostrock alteration with alkaline solution and nitrate effect, and (3) alternative technology development including decomposition of nitrate.

JAEA Reports

A Study for the safety evaluation of geological disposal of TRU waste and influence on disposal site design by change of amount of TRU waste (Joint research)

Hasegawa, Makoto; Kondo, Hitoshi; Kamei, Gento; Hirano, Fumio; Mihara, Morihiro; Takahashi, Kuniaki; Funabashi, Hideyuki; Kawatsuma, Shinji; Ueda, Hiroyoshi*; Oi, Takao*; et al.

JAEA-Research 2011-003, 47 Pages, 2011/02

JAEA-Research-2011-003.pdf:3.99MB

In 2009, NUMO and JAEA set up a technical commission to investigate the reasonable TRU waste disposal following a cooperation agreement between these two organizations. In this report, the calculation result of radionuclide transport for a TRU waste geological disposal system was described, by using the TIGER code and the GoldSim code at identical terms. Comparing the calculation result, a big difference was not seen. Therefore, the reliability of both codes was able to be confirmed. Moreover, the influence on the disposal site design (Disposal capacity: 19,000 m$$^{3}$$) was examined when 10% of the amount of TRU waste increased. As a result, it was confirmed that the influence of the site design was very little based on the concept of the Second Progress Report on Research and Development for TRU Waste Disposal in Japan.

Journal Articles

Natural analogues of cement; Overview of the unique systems in Jordan

Kamei, Gento; Alexander, W. R.*; Clark, I. D.*; Degnan, P.*; Elie, M.*; Khoury, H.*; Milodowski, A. E.*; Pitty, A. F.*; Salameh, E.*; Smellie, J. A. T.*

Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.141 - 147, 2010/10

JAEA Reports

Research and development for treatment and disposal technologies of TRU waste; JFY 2008 annual report

Kamei, Gento; Honda, Akira; Mihara, Morihiro; Oda, Chie; Murakami, Hiroshi; Masuda, Kenta; Yamaguchi, Kohei; Matsuda, Setsuro; Ichige, Satoru; Takahashi, Kuniaki; et al.

JAEA-Research 2009-046, 80 Pages, 2010/01

JAEA-Research-2009-046.pdf:9.1MB

Based on Japanese governmental policy and general scheme, research and development of geological disposal technology for TRU waste has been proceeding to improve reliability of the safety assessment of the co-locational disposal of TRU waste and of HLW, to expand the basement of generic safety assessment, and to develop the alternative technology to cope with the broad geologic environment of Japan. Japan Atomic Energy Agency is dealing with the assignments in the governmental generic scheme. We report here the progress of the studies at the end of H20 (2008) Japanese fiscal year.

Journal Articles

Concept of deep geological disposal for radioactive waste

Kamei, Gento

Nendo Handobukku Dai-3-Han, p.735 - 736, 2009/04

In the book that widely shows nature and use of clay, concept of geological disposal of radioactive waste is described. Clay will be used for the geological disposal system as the buffer material. Strategy to ensure the safety, components of the system and expected role of each component is summarized. The components of geological disposal system are engineered barriers (waste glass, overpack, and buffermaterial) and natural barrier (the host rock). Clay as the buffer material is expected to be chmical (eg. to controll overpack corrosion and radionuclides migration) and physical (eg. to preserve waste package) buffering functions.

JAEA Reports

Research and development for treatment and disposal technologies of TRU waste; JFY 2007 annual report

Kamei, Gento; Honda, Akira; Mihara, Morihiro; Oda, Chie; Murakami, Hiroshi; Masuda, Kenta; Yamaguchi, Kohei; Matsuda, Setsuro; Ichige, Satoru; Takahashi, Kuniaki; et al.

JAEA-Research 2008-082, 84 Pages, 2008/11

JAEA-Research-2008-082.pdf:2.52MB
JAEA-Research-2008-082(errata).pdf:0.15MB

Based on Japanese governmental policy and general scheme, research and development of geological disposal technology for TRU waste has been proceeding to improve reliability of the safety assessment of the co-locational disposal of TRU waste and of HLW, to expand the basement of generic safety assessment, and to develop the alternative technology to cope with the broad geologic environment of Japan. Japan Atomic Energy Agency is dealing with the assignments in the governmental generic scheme. We report here the progress of the studies at the end of H19 (2007) fiscal year, which are (1) treatment and packaging of TRU waste including applicability of calcination for unpacking and sorting of wastes, characterization and inspection methodology of TRU waste, (2) mechanical assessment for the near-field structure including model development and preparation, introduction of hostrock creep model and coupling analysis of deformation of hostrock and engineered barrier. (3) performance assessment of the disposal system including data acquisition and preparation on radionuclides migration, cementitious material alteration, bentonite and hostrock alteration with alkaline solution and nitrate effect, and (4) alternative technology development including decomposition of nitrate.

JAEA Reports

Development and management of the knowledge base for the geological disposal technology; Annual report 2006

Umeda, Koji; Oi, Takao; Osawa, Hideaki; Oyama, Takuya; Oda, Chie; Kamei, Gento; Kuji, Masayoshi*; Kurosawa, Hideki; Kobayashi, Yasushi; Sasaki, Yasuo; et al.

JAEA-Review 2007-050, 82 Pages, 2007/12

JAEA-Review-2007-050.pdf:28.56MB

This report shows the annual report which shows the summarized results and topic outline of each project on geological disposal technology in the fiscal year of 2006.

JAEA Reports

Research and development for treatment and disposal technologies of TRU waste; JFY 2006 annual report

Kamei, Gento; Honda, Akira; Mihara, Morihiro; Oda, Chie; Murakami, Hiroshi; Masuda, Kenta; Yamaguchi, Kohei; Nakanishi, Hiroshi*; Sasaki, Ryoichi*; Ichige, Satoru*; et al.

JAEA-Research 2007-067, 130 Pages, 2007/09

JAEA-Research-2007-067.pdf:28.78MB

After the publication of the 2nd progress report of geological disposal of TRU waste in Japan, policy and general scheme of future study for the waste disposal in Japan was published by ANRE and JAEA. This annual report summarized aim and progress of individual problem, which was assigned into JAEA in the published policy and general scheme. The problems are as follows; characteristics of TRU waste and its geologic disposal, treatment and waste production, quality control and inspection methodology for waste, mechanical analysis of near-field, data acquisition and preparation on radionuclides migration, cementitious material transition, bentonite and rock alteration in alkaline solution, nitrate effect, performance assessment of the disposal system and decomposition of nitrate as an alternative technology.

Journal Articles

Demonstrating feasible disposable concepts for long half-life, low heat generating radioactive wastes in Japan; An overview of project TRU-2

Martin, A. J.*; Kamei, Gento; Shiotsuki, Masao; Kuroda, Shigeki*

Proceedings of International Waste Management Symposium 2007 (WM '07) (CD-ROM), 12 Pages, 2007/03

In Japan, the Federation of Electric Power Companies and The Japan Atomic Energy Agency have been collaborating with relevant organizations to promote generic R&D for the safe geological disposal of TRU waste based on the technical achievements in Japan's HLW disposal program. A result of this collaborative effort was production of a recent progress report on the R&D for TRU waste disposal in Japan (project TRU-2). This paper is an overview of TRU-2 describing the key results and some unique methodologies developed.

Journal Articles

Present and future studies for geological disposal of long half life radionuclides bearing low feverish radioactive waste

Kuroda, Shigeki*; Kamei, Gento

Genshiryoku Bakkuendo Kenkyu, 13(1), p.31 - 35, 2006/10

Long half-life low heat generating radioactive waste (TRU waste) containing higher amount of radionuclide is considered to be disposed into a geologic formation. As an optimized geologic disposal of the waste, a technical possibility of co-disposal with high-level radioactive waste is being studied. An assessment result shows that a co-disposal is possible in a Japanese representative geologic environment by setting these repositories at a certain distance apart because reciprocal influences can be avoided. Atomic Energy Commission of Japan deliberated on the result and judged that the co-disposal concept described in the 2nd progress TRU report has a technical possibility. On the other side, future studies are required from the view points of (1) more reliable assessment of co-disposal, (2) expansion of generic assessment basis, and (3) flexible correspondence for wide geologic environmental conditions. This article shows a current status of the investigations of TRU waste disposal including an overview of the disposal concept and concrete items for the future studies.

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