Cross section asymmetry of polarized -ray elastic scattering

Omer, M.; Shizuma, Toshiyuki*; Koizumi, Mitsuo; Hajima, Ryoichi*; Hashimoto, Satoshi*; Miyamoto, Shuji*

LASTI Annual Report, 24, p.20 - 22, 2023/12

https://www.lasti.u-hyogo.ac.jp/annualreport/LASTI_Annual_Report_vol_24_2022.pdf

Long-term density-dependent groundwater flow analysis and its effect on nuclide migration for safety assessment of high-level radioactive waste disposal with consideration of interaction between fractures and matrix of rock formation in coastal crystalline groundwater systems

Park, Y.-J.*; Sawada, Atsushi; Ozutsumi, Takenori*; Tanaka, Tatsuya*; Hashimoto, Shuji*; Morita, Yutaka*

Proceedings of 3rd International Conference on Discrete Fracture Network Engineering (DFNE 2022) (Internet), 8 Pages, 2022/00

Safety analysis for underground disposal facilities for high-level radioactive waste requires thorough understanding of long-term groundwater flow and nuclide migration processes in geologic media. In the coastal subsurface systems, groundwater flow is defined by the complex interactions between freshwater of meteoric origin and denser saline water from the sea. In addition, sea levels are expected to fluctuate significantly due to a transgression and regression of the sea over the millions of years for safety analysis. This study presents long-term evolution of groundwater environment such as salinity concentration and flow velocity with focus of the interaction between fractures and matrix blocks in regional and near-field scale analysis framework for groundwater flow and nuclide migration for underground disposal facilities in hypothetical fractured crystalline coastal systems.

Study for development of the methodology for multi-scale hydrogeological modeling taking into account hydraulic heterogeneity caused by fracture network

Saegusa, Hiromitsu; Onoe, Hironori; Ishibashi, Masayuki; Tanaka, Tatsuya*; Abumi, Kensho*; Hashimoto, Shuji*; Bruines, P.*

JAEA-Research 2015-011, 59 Pages, 2015/10

JAEA-Research-2015-011.pdf:49.44MB

It is important to evaluate groundwater flow characteristics on several spatial scales for assessment of long-term safety on geological disposal of high-level radioactive wastes. An estimation of hydraulic heterogeneity caused by fracture network is significant for evaluation of the groundwater flow characteristics in the region of tens of meters square. Heterogeneity of equivalent hydraulic properties is needed to estimate for evaluation of the groundwater flow characteristics in the region of several km square. In order to develop the methodology for multi-scale hydrogeological modeling taking into account the hydraulic heterogeneity, spatial distribution of fractures and their hydraulic properties have been modeled using discrete fracture network (DFN) model. Then, hydrogeological continuum model taking into account the hydraulic heterogeneity has been estimated based on the DFN model. Through this study, the methodology for multi-scale hydrogeological modeling according to type of investigation data has been proposed.

Development of the supervisory systems for the ITER diagnostic systems in JADA

Yamamoto, Tsuyoshi; Hashimoto, Yasunori*; Serizawa, Yasunori*; Inamoto, Shuji*; Sato, Kazuyoshi; Sugie, Tatsuo; Takeuchi, Masaki; Kawano, Yasunori

Fusion Engineering and Design, 89(5), p.532 - 535, 2014/05

https://doi.org/10.1016/j.fusengdes.2014.01.049

The diagnostic systems are essential for the plasma control and physics understandings. JAEA has proposed the new concept of supervisory system which manages operation sequences, current state and configuration parameters for the measurement based on our experiences in operating plasma diagnostic systems. We designed the supervisory system satisfying the requirements from both CODAC system and diagnostic systems. In our design, the tool which converts operational steps described as flowcharts into EPICS Records templates is introduced. This tool will ensure reduction of the system designers' efforts. We also designed the sequencing simulator that can submit transition commands internally instead of CODAC system for the calibration and commissioning. The mechanism which changes the limit values and consistency check algorithms in accordance with the conditions of the diagnostics system is also proposed.

Study for establishment of the methodology for hydrogeological modeling using hydraulic discrete fracture networks (Study on hydrogeology in crystalline fractured rock)

Ando, Kenichi*; Tanaka, Tatsuya*; Hashimoto, Shuji*; Saegusa, Hiromitsu; Onoe, Hironori

JAEA-Research 2012-022, 60 Pages, 2012/08

JAEA-Research-2012-022.pdf:8.51MB

In this study, water conducting features in Toki granite were defined by the interpretation and integration of geological and hydrogeological data obtained from the borehole investigation in the Phase I of the MIU Project and Regional Hydrogeological Study. Then, the hydrogeological model of Block scale was constructed using hydraulic discrete fracture networks, and equivalent hydraulic conductivities in Block scale were calculated. And, adequacy of equivalent hydraulic conductivities in Block scale was confirmed using result of hydraulic packer tests.

Preliminary study on development of a methodology for evaluating the performance of host rock for geological disposal based on surface-based investigations

Inagaki, Manabu*; Tanaka, Tatsuya*; Hashimoto, Shuji*; Maekawa, Keisuke; Shibata, Masahiro

JAEA-Research 2011-056, 37 Pages, 2012/03

JAEA-Research-2011-056.pdf:8.64MB

In Japan, a step-wise approach is applied in the site selection process for the geologic disposal site. Preliminary surface-based investigations will be followed by detailed investigations. The basic repository concept, including underground design and layout, will be discussed at the end of surface-based investigations. The repository concept will depend on the spatial extent of the candidate rock formation(s) and their barrier performance. However, information obtained from the surface is limited and includes uncertainties. It is thus important to assess host rock performance considering uncertainties. In this study, methodology for evaluation of geological conditions has been developed that focuses on determining the usable volume of host rock with specific performance characteristics. Initially, multiple performance indices have been discussed and defined from the viewpoint of barrier performance. Then the evaluation procedure is illustrated by using the dataset obtained from the Horonobe Underground Research Laboratory Project. Finally the proposed procedure is reviewed and future challenges are extracted.

The Project for grouting development for high level radioactive waste repository, 5; Evaluation of geological structure for fractures network modeling in the crystalline rock site

Abumi, Kensho*; Tanaka, Tatsuya*; Hashimoto, Shuji*; Nakanishi, Tatsuro; Tsuda, Hidenori

Doboku Gakkai Heisei-23-Nendo Zenkoku Taikai Dai-66-Kai Nenji Gakujutsu Koenkai Koen Gaiyoshu (DVD-ROM), p.73 - 74, 2011/09

no abstracts in English

Studies on grouting performance in Mizunami Underground Research Laboratory (Contract research)

Kawamura, Hideki*; Ando, Kenichi*; Noda, Masaru*; Tanaka, Tatsuya*; Matsuda, Takeshi*; Fujii, Haruhiko*; Hashimoto, Shuji*; Ueda, Tadashi*; Matsui, Hiroya; Takeuchi, Shinji; et al.

JAEA-Technology 2009-081, 182 Pages, 2010/03

JAEA-Technology-2009-081.pdf:28.89MB

Grouting has practical importance for the reduction of groundwater inflow into excavations during construction of underground facilities. Considering the performance assessment of a radioactive waste repository, the performance of the engineered barrier system could be adversely affected by a high pH plume generated from grout. Therefore, a quantitative estimation of the effectiveness of grouting and grout material is essential. This study has been performed in the Mizunami URL being excavated in crystalline rock as a part of the Project for Grouting Technology Development for the Radioactive Waste Repository funded by METI, Japan. The aims were to evaluate the applicability of existing grouting technology and to develop methodology to determine the distribution of grout and change in hydraulic properties of the grouted rock volume. The target rock is the volume of rock around a planned refuge niche where the pre-excavation grouting was performed at 200-m depth from ground surface. After excavation of the refuge niche, ten boreholes were drilled and different kinds of investigations were carried out during and after drilling. The results were integrated and groundwater flow analysis of pre and post excavation grouting conditions were carried out to estimate quantitatively the effect of pre-excavation grouting. The results suggest that current pre-excavation grouting technology is effective for reduction of groundwater inflow into excavations and that hydraulic conductivity of the surrounding rock can be reduced by more than one order of magnitude.

Study on grouting performance for underground construction in crystalline rock, 3; Numerical simulation of water-tightness improvement

Tanaka, Tatsuya*; Matsui, Hiroya; Hashimoto, Shuji*; Ando, Kenichi*; Takeuchi, Shinji; Saegusa, Hiromitsu

Dai-38-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.143 - 148, 2009/01

This study aims to establish techniques for grouting, and evaluation of the effects of grouting on the geological environment, to be applied in the field of high level radioactive waste disposal in the deep underground. A block-scale hydrogeological model has been generated using discrete fracture networks based on data obtained from the short-borehole investigation campaign performed at the research tunnel around which grouting has been carried out. The grouting performance in terms of reducing the water inflow rate was evaluated by groundwater flow simulation. Lessons learned applicable to future studies of in-situ testing have been addressed.

Study on the methodology for hydrogeological site descriptive modelling by discrete facture networks

Tanaka, Tatsuya*; Ando, Kenichi*; Hashimoto, Shuji*; Saegusa, Hiromitsu; Takeuchi, Shinji; Amano, Kenji

Dai-36-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.267 - 272, 2007/01

no abstracts in English