Myagmarjav, O.; Iwatsuki, Jin; Tanaka, Nobuyuki; Noguchi, Hiroki; Kamiji, Yu; Ioka, Ikuo; Kubo, Shinji; Nomura, Mikihiro*; Yamaki, Tetsuya*; Sawada, Shinichi*; et al.
International Journal of Hydrogen Energy, 44(35), p.19141 - 19152, 2019/07
Osawa, Takahito; Ninomiya, Kazuhiko*; Yoshida, Go*; Inagaki, Makoto*; Kubo, Kenya*; Kawamura, Naritoshi*; Miyake, Yasuhiro*
JPS Conference Proceedings (Internet), 8, p.025003_1 - 025003_6, 2015/09
We report a new elemental analysis system that uses an intense negative-muon beam at J-PARC Materials and Life Science Experimental Facility, Muon Science Establishment. This paper presents the preliminary results of measurements for meteorites and standard material. The main system components are a water-cooled electromagnet, an Al flight tube, an Al sample chamber, a lead shielding body, and a Ge detector. Optimum currents for the electromagnet were determined by recording beam profiles with a CCD camera; the muon beam was shaped by collimators. The background and signal-to-noise ratio was significantly better than that obtained in a previous study, and all significant elements in the meteorite and standard samples were detected. Thus, this system can be used for muonic X-ray analysis of extraterrestrial materials.
Tampo, Motonobu*; Hamada, Koji*; Kawamura, Naritoshi*; Inagaki, Makoto*; Ito, Takashi; Kojima, Kenji*; Kubo, Kenya*; Ninomiya, Kazuhiko*; Strasser, P.*; Yoshida, Go*; et al.
JPS Conference Proceedings (Internet), 8, p.036016_1 - 036016_6, 2015/09
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.
Tsusaka, Kimikazu; Inagaki, Daisuke; Nago, Makito*; Kamemura, Katsumi*; Matsubara, Makoto*; Shigehiro, Michiko*
Proceedings of ITA-AITES World Tunnel Congress 2013 (WTC 2013)/39th General Assembly, p.2014 - 2021, 2013/05
Japan Atomic Energy Agency (JAEA) has been constructing three shafts to a depth of 500 m in the Horonobe Underground Research Laboratory Project. In this study, in consideration of support patterns installed, a relationship between the rock mass properties and mechanical response to excavation was investigated in detail during the construction of the East Access Shaft below a depth of 250 m. Since the shaft has intersected several faults with the size greater than the shaft diameter, some amounts of rock spalling have occurred and cracks have severely developed in a concrete lining in highly fractured zones. The results of pre-excavation grouting were compared with the results of fracture mapping in the shaft wall obtained during the shaft sinking. Applicability of several support patterns installed to control massive spalling during the shaft sinking was also analysed using the results of geometry profiling of shaft wall using a three-dimensional laser scanner and convergence measurements. As a result, based the empirical relationships among the characteristics of rocks, dimension of spalling, damage of a concrete lining and support patterns, a flow chart for selection of span of a concrete lining was proposed to control its severe damage prior to shaft excavation.
Tsusaka, Kimikazu; Inagaki, Daisuke; Nago, Makito*; Koike, Masashi*; Matsubara, Makoto*; Sugawara, Kentaro*
Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.911 - 916, 2013/01
A repository for high-level radioactive waste in deep underground consists of several underground structures such as access and disposal drifts and shafts. In deep geological disposal project, a shaft is the first underground structure to be constructed and the last one to be backfilled. Therefore, the stability of shaft is one of key factors to steadily manage the project in the construction and operation phases. In this paper, the authors discuss influence of rock spalling on concrete lining in shaft sinking. Japan Atomic Energy Agency has been constructing three shafts (one is for ventilation and the others are for access use) up to a depth of 500 m in the Horonobe Underground Research Laboratory. During the construction of the Ventilation Shaft (4.5 m in diameter) below a depth of 250 m, rock spalling occurred at several depths and an open crack has developed in a concrete lining installed just above rock spalling. The authors have measured geometry of shaft wall by using three-dimensional laser scanner. They also conducted numerical analysis in order to calculate change in stress distribution and deformation induced by rock spalling in a concrete lining and the surrounding rock. As a result, it was clarified that rock spalling induced tensile stress in the vertical direction in a concrete lining. Especially, the tensile stress in a concrete lining was likely to exceed tensile strength of a concrete lining in the case that it developed more than 100 cm in depth.
Tsusaka, Kimikazu; Inagaki, Daisuke; Tokiwa, Tetsuya; Yokota, Hideharu; Nago, Makito*; Matsubara, Makoto*; Shigehiro, Michiko*
Proceedings of ITA-AITES World Tunnel Congress 2012 (WTC 2012)/38th General Assembly (CD-ROM), 8 Pages, 2012/05
In the Horonobe URL Project, three shafts are planned to be excavated up to the depth of 500 m in the Neogene sedimentary rocks. The host rock of the URL site is comprised of diatomaceous and siliceous mudstones, which are the Koetoi and Wakkanai Formations, respectively. Approximately 100 m thick fracture zone with high hydraulic conductivity develops above about 400 m in depth in the Wakkanai Formation. The shaft sinking through the fracture zone is the most challenging issue from the aspect of tunnel engineering in the project. In the fracture zone, there is high possibility of severe breakout and spalling in shaft wall because the shafts might be intersecting faults with the size greater than shaft diameter in addition to low intact rock strength at great depth. In practice, prior to the construction of the Ventilation Shaft through the fracture zone below a depth of 250 m, the three dimensional fault distribution were predicted by integrating borehole investigation results and geological response to pre-excavation grouting operation. The countermeasure was also designed against massive spalling. During the shaft sinking, fracture mapping of shaft wall was carried out in order to evaluate the prediction of fault distribution. Roughness of shaft wall was also measured by three dimensional laser scanner in order to investigate the shape and volume of spalling resulting from the excavation work. Consequently, the Ventilation Shaft has successfully been constructed through the fracture zone. This is because the prediction of fault distribution was accurate, and the countermeasure against concrete lining damage due to spalling was promptly applied.
Tsusaka, Kimikazu; Inagaki, Daisuke; Nago, Makito*; Matsubara, Makoto*
Chika Kukan Shimpojiumu, Rombunshu, 17, p.155 - 162, 2012/01
Japan Atomic Energy Agency has been constructing an underground research laboratory in order to enhance the reliability of relevant disposal technologies of high-level radioactive waste in Horonobe, Hokkaido. A ventilation shaft (4.5 m in diameter) and two access shafts (6.5 m in diameter) are being excavated through the Neogene sedimentary rocks until the depth of 500 m. Based on the results of borehole investigation and pre-grounting operation in bedrock with high permeability from 250 m to 375 m in depth, the three dimensional fracture distribution map were built and the locations with high possibility of spalling in shaft wall in response to excavation were predicted prior to the shaft sinking from a depth of 250 m. Some amounts of spalling has occurred in several depths during shaft sinking from 250 m to 280 m in depth. The shape of each spalling was measured by means of three dimensional laser scaning system. As a result, spalling in shaft wall occurred along the faults predicted based on the three dimensional fracture distribution. In addition, spalling by brittle failure in shaft wall was also observed with a few extensile fractures which were expected to be induced by excavation. Based on the shape of spalling, it was confirmed that the applied shaft sinking procedure properly prevented a massive spalling.
Sasaki, Takuo*; Suzuki, Hidetoshi*; Inagaki, Makoto*; Ikeda, Kazuma*; Shimomura, Kenichi*; Takahashi, Masamitsu; Kozu, Miwa*; Hu, W.; Kamiya, Itaru*; Oshita, Yoshio*; et al.
IEEE Journal of Photovoltaics, 2(1), p.35 - 40, 2012/01
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.
Kawamura, Makoto; Ebashi, Takeshi; Makino, Hitoshi; Niizato, Tadafumi; Yasue, Kenichi; Inagaki, Manabu; Oi, Takao
Oyo Chishitsu, 51(5), p.229 - 240, 2010/12
Uplift, subsidence, denudation, and sedimentation are phenomena over long-term in a regional scale. It is difficult to ignore the impacts of those phenomena on a disposal system completely in long-term. Therefore, type and extent of the impacts on geological and disposal environmental conditions, and disposal systems need to be evaluated quantitatively in order to develop perturbation scenarios. We have been developing a systematic methodology to develop perturbation scenarios based on the appropriate understanding of those phenomena. The variety of the change of geological environment and evolution pattern of the environment, which are caused by the variation of the uplift, subsidence, denudation, sedimentation phenomena and those rates, are understood by arranging the information in the framework of the thermal-hydrological-mechanical-chemical-geometrical (T-H-M-C-G) system, and the impacts of those environmental change to the performance of the repository system are also examined by using the T-H-M-C-G system. In this study, firstly, the potential changes of the geological environment were identified by examination of possible combinations of the uplift/denudation and subsidence/ sedimentation. The effects of the initial environmental condition are also considered. Geohistorical information and View of Modern analogue theory should be used in this stage. This procedure is essential to set up the scenarios regarding uplift/denudation and subsidence/sedimentation, to clarify the trend and/or range of the change of the geological environmental conditions. Then, the phenomena which give the large impacts to a disposal system were extracted based on the T-H-M-C-G system. By applying the developed framework which deals with the impacts on the HLW disposal system realistic view and builds evaluation scenarios and models based on step wise manner, we acquired the prospect that realistic uplift and denudation scenario could be built to this examination procedure.
Maekawa, Keisuke; Makino, Hitoshi; Kurikami, Hiroshi; Niizato, Tadafumi; Inagaki, Manabu; Kawamura, Makoto*
Proceedings of 13th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM 2010) (CD-ROM), p.71 - 80, 2010/10
It is important for establishing safety assessment techniques of HLW geological disposal to understand groundwater flow and solute transport. We have carried out groundwater flow and solute transport analysis using geological and hydrological information from surface-based investigations in the Horonobe area. From this study, a methodology to integrate activities from site investigations and evaluation to solute transport analysis was tested. We have been also carrying out a simulation of groundwater flow and salinity concentration distribution using information on geological evolution considering the impacts of natural events and processes. From the result, we could outline the impacts of natural events and processes on geological environments. We plan to apply a methodology of groundwater flow and solute transport analysis to the shallow part, the Horonobe coastal area. It must be important techniques in support of generic safety assessment for future geologic disposal in Japan.
Kawamura, Makoto; Makino, Hitoshi; Sasao, Eiji; Niizato, Tadafumi; Yasue, Kenichi; Asamori, Koichi; Umeda, Koji; Ishimaru, Tsuneari; Osawa, Hideaki; Ebashi, Takeshi; et al.
JAEA-Research 2010-027, 85 Pages, 2010/09
Japan Atomic Energy Agency (JAEA) have developed a formal evaluation method to assess the potential impacts of natural phenomena (earthquakes and faulting; volcanism; uplift, subsidence, denudation and sedimentation; climatic and sea-level changes) on a high level radioactive waste (HLW) disposal system for the purpose of maintenance of evaluation method for potential impacts of natural phenomena within more realistic view. In this report, we developed a framework as a part of the total system performance assessment for two purposes: the first one is quantification of relationship of characteristic of natural phenomena between geological environmental conditions (T-H-M-C-G), and the other one is quantification of relationship of T-H-M-C-G condition between parameters of performance assessment. We tried to apply the framework to all natural phenomena to confirm the effectiveness of the framework. On the other hand, we applied an argument-diagram that was developed one of the methods of the knowledge management to elicit future tasks. As a result, to apply the framework, we could show that information integration could carry out efficiently, and information integration was attained by the common framework by combining information on geohistory and existing information of natural phenomena and geological environmental conditions as modern-analogue. We could show that suitable scenarios might be chosen by information integration. Furthermore, we were able to elicit future tasks to this study by applying the argument-diagram.
Shimizu, Yuta*; Inagaki, Makoto*; Kumada, Takayuki; Kumagai, Jun*
Journal of Chemical Physics, 132(24), p.244503_1 - 244503_8, 2010/06
We performed electron spin resonance studies of trapped electrons and H radical cations produced by radiolysis of solid para-H, para-H-ortho-D, and para-H-HD mixtures. Yields of both trapped electrons, and H radical cations, and its isotopic analogues increased with increasing the concentration of ortho-D and HD concentrations in solid para-H. We have concluded that electrons were found trapped nearby an ortho-D or an HD in solid para-H due to a the long-range charge-induced dipole and charge-induced quadrupole interactions between an electrons and an isotopic hydrogen molecules.
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.
Oi, Takao; Inagaki, Manabu; Kawamura, Makoto; Ebashi, Takeshi
JAEA-Research 2008-111, 32 Pages, 2009/03
A demonstration of the usefulness of the systematic approach to evaluate the importance of concerns affecting the geological disposal of radioactive wastes.
Oi, Takao; Inagaki, Manabu; Kawamura, Makoto; Ebashi, Takeshi
Materials Research Society Symposium Proceedings, Vol.1124, p.407 - 412, 2009/00
In the safety assessment of geological disposal system of radioactive waste, diverse apprehensions have been extracted from the viewpoint of the impact on the safety and the researches relating to those have been carried out strenuously. However, systematical investigation for presenting the relative importance of those has so far scarcely been conducted. The demonstration of the importance is critical issue to contribute the improvement of reliability of safety assessment. In this study, the following investigations were carried out with the goal of developing the systematic approach which can present the relative importance of the apprehensions: (1) Establishment of Total Assessment Work Frame [TAWF], (2) Establishment of the organaization procedure for evaluating the relative importance.
Miyahara, Kaname; Inagaki, Manabu; Kawamura, Makoto; Ebina, Takanori*
Proceedings of 2008 International High-Level Radioactive Waste Management Conference (IHLRWM 2008) (CD-ROM), p.593 - 599, 2008/09
This paper illustrated how to conduct "what if?" calculations in a transparent manner based on a developed formal procedure in order to treat perturbations of disruptive fault movement on a HLW disposal system. Calculation cases are defined due to stepwise combination of loss of key safety functions as what if? assumptions. The calculation results show effectiveness and robustness of the multibarrier system, even considering the most extreme combination of what if assumptions.