Miyahara, Kaname; Kawase, Keiichi
Genshiryoku No Ima To Ashita, p.159 - 167, 2019/03
This manuscript overviews lessons learned from decontamination pilot projects towards implementation of regional remediation after the environmental contamination due to the Fukushima Daiichi Nuclear Power Plant Accidents.
Transactions of the American Nuclear Society, 117(1), p.51 - 52, 2017/10
This presentation highlights JAEA's challenges for contributing to recovering the previous life of residents and the development of resilient communities in Fukushima Prefecture based on considering needs of local people on the environmental restoration categorized by the state of evacuation orders and the lifting of such orders.
Miyahara, Kaname; Ohara, Toshimasa*
Nippon Genshiryoku Gakkai-Shi, 59(5), p.282 - 286, 2017/05
This review highlights JAEA and NIES's challenges for enhancing Fukushima environmental resilience based on carrying out multifaceted research working with many public and private sector organizations and academia.
Ohara, Toshimasa*; Miyahara, Kaname
Global Environmental Research (Internet), 20(1&2), p.3 - 13, 2017/03
Toward the environmental regeneration in Fukushima Prefecture and other areas after the Fukushima Daiichi Nuclear Power Station accidents, JAEA and NIES working with many public and private sector organizations and academia have carried out multifaceted research that will help to restore the environment of affected areas. These challenging efforts need to be further strengthened.
Miyahara, Kaname; Iijima, Kazuki; Saito, Kimiaki
Jiban Kogakkai-Shi, 63(11/12), p.62 - 69, 2015/11
This review provides a concise overview of knowledge and experience gained from the activities for environmental remediation after the Fukushima Dai-ichi accident as input for developing a technical knowledge base including remediation technologies which is translated into actions that enable the rapid return of evacuees. It is reflecting JAEA's key role in the research associated with both remediation of contaminated areas and the natural processes influencing contamination migration in non-remediated areas, working together with a number of Japanese and international organisations and research institutes. This review also provides a perspective on the future actions required to remediate areas outside the Fukushima Dai-ichi site.
Miyahara, Kaname; McKinley, I. G.*; Saito, Kimiaki; Iijima, Kazuki; Hardie, S. M. L.*
Nuclear Engineering International, 60(736), p.12 - 14, 2015/11
Remediation work in Fukushima is based on a comprehensive technical knowledge base, which is translated into actions that enable the rapid return of evacuees but also provides a globally valuable resource for disaster planning and contaminated site remediation.
Miyahara, Kaname; McKinley, I. G.*; Saito, Kimiaki; Hardie, S. M. L.*; Iijima, Kazuki
JAEA-Review 2015-001, 90 Pages, 2015/03
This report provides a concise overview of knowledge and experience gained from the activities for environmental remediation after the Fukushima Dai-ichi accident. It is specifically tailored for international use to establish or refine the technical basis for strategic, off-site response to nuclear incidents. It is produced by JAEA, reflecting JAEA's key role in the research associated with both remediation of contaminated areas and the natural processes influencing contamination migration in non-remediated areas, working together with a number of Japanese and international organisations and research institutes. The report also provides a perspective on the future actions required to remediate all areas outside the 1F site.
Doboku Gakkai-Shi, 100(3), p.16 - 17, 2015/03
Towards Fukushima environmental restoration, knowledge and experience gained from decontamination pilot projects are highlighted and challenges for management of removed soil and wastes for interim storage facility are encouraged based on application of technologies and methods developed mainly in civil engineering to face unprecedented large scale of decontamination areas and to treat large volumes of removed soil and wastes.
Kihara, Shinji; Amazawa, Hiroya; Sakai, Akihiro; Nakata, Hisakazu; Kugo, Teruhiko; Matsuda, Norihiro; Oizumi, Akito; Sasamoto, Hiroshi; Mitsui, Seiichiro; Miyahara, Kaname
JAEA-Research 2013-033, 320 Pages, 2014/07
JAEA performed decontamination experiments at two test sites that combined a range of buildings and different types of land use, located in Date and Minami Soma municipalities as field pilot projects in order to accumulate knowledge and data for full-scale decontamination activities performed by local governments. In the pilot projects, we established its plan using practical decontamination methods that can be easily implemented, according to decontamination targets (e.g., forests, agricultural land, residential house and roads) at each site. As a result of the decontamination, the average air dose rates were reduced to approximately one half of the values before decontamination.
Ebashi, Takeshi; Kawamura, Makoto*; Inagaki, Manabu*; Koo, Shigeru*; Shibata, Masahiro; Itazu, Toru; Nakajima, Kunihiko*; Miyahara, Kaname; Apted, M. J.*
Materials Research Society Symposium Proceedings, Vol.1665, p.39 - 45, 2014/07
In Japan, the likelihood of uplift/erosion on repository performance and waste isolation can be typically greatly reduced or excluded by careful siting, however, the inability to completely exclude the uplift/erosion scenario may require an analysis of the consequences of such a scenario. For this purpose, an assessment approach has been developed to more realistically treat the effect of uplift/erosion for a hypothetical repository located in sedimentary host rock. A key advantage to this approach is the extrapolation of the geohistory of modern analogue sites to develop credible initial inputs for future volunteer sites that may be poorly characterized at the initial stages of site investigation. In addition, the approach provides a systematic basis for bounding the range of possible evolution in thermal-hydrological-mechanical-chemical conditions of a repository experiencing different uplift/ erosion rates.
Miyahara, Kaname; Niizato, Tadafumi; Iijima, Kazuki
Ringyo Fukushima, (597), P. 5, 2014/05
Present condition of the Fukushima forest; F-TRACE Project: Accumulation of the scientific evidences to secure the safety and reassurances of the people
Miyahara, Kaname; Tokizawa, Takayuki; Nakayama, Shinichi
Materials Research Society Symposium Proceedings, Vol.1518, p.245 - 256, 2013/10
After the Fukushima Dai-ichi accident, Japan Atomic Energy Agency (JAEA) was chosen by the Government to conduct decontamination model projects at selected sites. Despite tight boundary conditions in terms of timescale and resources, the decontamination model projects provide a good basis for developing recommendations on how to assure clean-up efficiency and reduce time, cost, subsequent waste management and environmental impact. This can be summarised in terms of site characterisation and data interpretation, clean-up and waste minimisation and storage.
Tagawa, Akihiro; Nakayama, Shinichi; Miyahara, Kaname
Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.944 - 951, 2013/03
A wide area of Fukushima Prefecture was contaminated with radioactivity released by the Fukushima Daiichi nuclear accident. Japan Atomic Energy Agency (JAEA) has been involved in mitigating the effects of the accident in a diversifying ways from the emergency dispatch of radiation experts immediately after the accident and radiation monitoring in the affected areas to demonstrate of decontamination for a variety of targets, public affairs with evacuated populations, and research and development activities for environmental remediation. The decontamination related activity is one of the major contributions of JAEA to environmental remediation, providing technical supports to the unprecedented regional decontamination in Fukushima that have been carried out by the central and local governments of Japan. JAEA's experiences and expertise obtained are overviewed in this paper focusing on the decontamination pilot project.
Miyahara, Kaname; Tokizawa, Takayuki; Nakayama, Shinichi
IAEA-CN-211 (Internet), 2 Pages, 2013/01
After the Fukushima Dai-ichi nuclear accident, Japan Atomic Energy Agency (JAEA) was chosen by the Government to conduct decontamination pilot projects at selected sites in Fukushima prefecture. Despite tight boundary conditions in terms of timescale and resources, the demonstration projects have served their primary purpose of development of a knowledge base to support more effective planning and implementation of stepwise regional remediation of the evacuated zone. A range of established, modified and newly developed techniques have been tested under realistic field conditions and their performance characteristics determined. The results of the project can be summarised in terms of site characterisation, clean-up and waste management.
Miyahara, Kaname; Tachi, Yukio; Kitamura, Akira; Mitsui, Seiichiro; Sawada, Atsushi; Shibata, Masahiro; Neall, F.*; McKinley, I. G.*
Proceedings of 2011 International High-Level Radioactive Waste Management Conference (IHLRWMC 2011) (CD-ROM), p.292 - 298, 2011/04
As the Japanese deep geological disposal programme prepares for milestones at which volunteer sites need to be compared, it is critical that any supporting post-closure safety assessment is done as realistically as possible. Because of the subtle system understanding needed to integrate diverse theoretical, laboratory, field and analogue models, data and observations into the high-level parameters that are incorporated into performance assessment models, normal QA procedures tend to fail completely. This problem is discussed further in this paper and solutions outlined, which build on recent developments of supporting knowledge engineering tools.
Fujita, Tomoo; Taniguchi, Naoki; Matsui, Hiroya; Tanai, Kenji; Maekawa, Keisuke; Sawada, Atsushi; Makino, Hitoshi; Sasamoto, Hiroshi; Yoshikawa, Hideki; Shibata, Masahiro; et al.
JAEA-Research 2011-001, 193 Pages, 2011/03
This report summarizes the progress of research and development on geological disposal during the surface-based investigation phase (2001-2005) in the Horonobe Underground Research Laboratory project, of which aims are to apply the design methods of geological disposal and mass transport analysis to actual geological conditions obtained from the surface-based investigations in the Horonobe Underground Research Laboratory project as an example of actual geological environment.
Miyahara, Kaname; Kawamura, Makoto*; McKinley, I. G.*; Inagaki, Manabu*; Ebina, Takanori*
Journal of Nuclear Science and Technology, 48(7), p.1069 - 1076, 2011/00
In Japan, uplift/erosion scenarios must be analysed even if they occur far in the future, as no assessment cut-off times have yet been defined. For this purpose, the geological record of river terrace formation and their long term evolution has been studied further, with the aim of constructing a more realistic fluvial erosion model compared with the original, rather simple cyclic fluvial erosion model developed in a previous study. The model allows the consequences of erosion of the repository to be assessed, as before using comparisons with natural radionuclide fluxes. This paper describes a conceptual model based on a generalization of field observations in relevant settings and discusses resultant analyses, which again illustrate the effectiveness and robustness of the reference HLW disposal system.
Itazu, Toru; Inagaki, Manabu; Kato, Tomoko; Suzuki, Yuji*; Oyamada, Kiyoshi*; Ebashi, Takeshi; Kawamura, Makoto; Ebina, Takanori*; Miyahara, Kaname
JAEA-Review 2009-015, 59 Pages, 2009/07
The project of high-level radioactive waste disposal is in the stage of site selection in Japan, and the site-specific performance assessment using the methodology of site-generic study has been developed after the publication of the second progress report (H12). In the same way, biosphere assessment using the behavior of radionuclides, which depends on the site-specific condition, has been started. In this paper, the following issues have been addressed. (1) Survey of the foreign literature relating to the surface and near- surface hydrology for biosphere assessments. (2) Survey of the domestic literature of flow and transport in subsurface systems valuable for biosphere assessments. (3) Trial of transport analysis in surface and near-surface environment of the model site. (4) The setting and boundary conditions of model used for the surface and near-surface hydrological analysis. About the fist issue, from literature of Sweden, we studied the calculation of the dose with account to radionuclides migration in the Quaternary. Concerning the second item, collecting and compiling the useful information for the surface and near-surface hydrological analysis from literature related to groundwater flow and pollution survey in Japan, we learned about the environmental tracer method and so on. Concerning the third point, transport analysis in surface and near-surface environment using site-specific data for sensitivity analysis after this has been carried out to check out the influence of some parameters on transport phenomena, and the relative high sensitivity of the difference of the source positions were shown. Concerning the fourth item, we examined the setting and the boundary conditions of model whose outputs include groundwater flow and transport rate into river, lake, sea. These outputs are used as inputs of biosphere assessment model.
Miyahara, Kaname; Inagaki, Manabu; Kawamura, Makoto; Ebina, Takanori*; McKinley, I. G.*
Materials Research Society Symposium Proceedings, Vol.1193, p.177 - 184, 2009/05
Uplift and erosion cannot be generally precluded in Japan, therefore needs to be treated. In particular, uplift and erosion will cause major disruption of the engineered and natural barriers when the repository is exposed at the ground surface, although erosion of the repository should be excluded for very long times by careful siting and design. In Japan, uplift/erosion scenarios must be analysed, even if they occur far in the future as no assessment cut-off times have yet been defined. For this purpose, an argumentation method is being developed to allow sensible scenarios to be constructed. This paper discusses procedures to derive relevant conceptual models and resultant analyses in a credible manner which illustrates the effectiveness and robustness of the HLW disposal system, using relevant yardsticks based on natural radionuclide fluxes.
Ebashi, Takeshi; Kawamura, Makoto; Inagaki, Manabu; Koo, Shigeru*; Shibata, Masahiro; Itazu, Toru; Nakajima, Kunihiko*; Miyahara, Kaname
JAEA-Research 2008-117, 36 Pages, 2009/03
It is considered that it is possible to avoid the effect of the uplift and denudation process on geological disposal system by siting and a repository design. However, since the uplift/denudation continues far into the future, it is important to enhance the confidence of the methodology to evaluate such an effect, based on the understanding of geohistorical information and potential impact on the disposal system. This paper presents an evolution pattern of the geological environment and the influence analysis in terms of system performance affected by the uplift and denudation process based on the relevant conceptual models for groundwater scenarios of the disposal system for a hypothetical sedimentary rock. As a result, it is indicated that the conceptual model is capable to identify a specific combination of patterns of system evolution of the geological environment in terms of features on the uplift and denudation process, and also provides technical basis for setting up parameters of nuclide migration model and the subsequent influence analysis. Consequently, it is also indicated that the evaluation methodology applied in this study is valuable to evaluate the uplift/denudation phenomena with specific geological environment, and the results obtained by the analysis could be valuable information for site investigation and/or the prediction of a future change trend for the uplift/denudation.