Effect of water vapor on re-saturation process in EBS performance of re-saturation process by Thermo-Hydro-Mechanical coupled analysis

Sato, Shin*; Ono, Hirokazu; Tanai, Kenji; Yamamoto, Shuichi*; Fukaya, Masaaki*; Shimura, Tomoyuki*; Niunoya, Sumio*

Jiban Kogaku Janaru (Internet), 15(3), p.529 - 541, 2020/09

https://doi.org/10.3208/jgs.15.529

no abstracts in English

Prediction of ambient dose equivalent rates for the next 30 years after the accident

Kinase, Sakae; Takahashi, Tomoyuki*; Sato, Satoshi*; Yamamoto, Hideaki; Saito, Kimiaki

Proceedings of International Symposium on Radiological Issues for Fukushima's Revitalized Future, p.40 - 43, 2015/00

http://www.rri.kyoto-u.ac.jp/anzen_kiban/outcome/Symposium'15_Proceedings_EN.pdf#page=50

To support recovery and rehabilitation in Fukushima, prediction models have been developed for ambient dose equivalent rate distribution within the 80 km-radius around the Fukushima Daiichi Nuclear Power Plant. The prediction models that are based on bi-exponential functions characterized by ecological half-lives of radioactive caesium for land-use, enable Fukushima residents to obtain distribution maps of ambient dose equivalent rates for the next 30 years after the accident. Model parameters were evaluated using ambient dose equivalent rates through car-borne surveys. The model parameters in deciduous and evergreen forest areas were found to be different from those in other areas. In addition, it was found that distribution maps of ambient dose equivalent rates for the next 30 years after the accident, created by the prediction models would be useful for follow-up of the radiological situation.

Mizunami Underground Research Laboratory Project, Annual report for fiscal year 2011

Kunimaru, Takanori; Mikake, Shinichiro; Nishio, Kazuhisa; Tsuruta, Tadahiko; Matsuoka, Toshiyuki; Ishibashi, Masayuki; Sasao, Eiji; Hikima, Ryoichi; Tanno, Takeo; Sanada, Hiroyuki; et al.

JAEA-Review 2013-018, 169 Pages, 2013/09

JAEA-Review-2013-018.pdf:15.71MB

Japan Atomic Energy Agency (JAEA) at Tono Geoscience Center (TGC) is pursuing a geoscientific research and development project namely the Mizunami Underground Research Laboratory (MIU) Project in crystalline rock environment in order to construct scientific and technological basis for geological disposal of High-level Radioactive Waste (HLW). The MIU Project has three overlapping phases: Surface-based Investigation phase (Phase I), Construction phase (Phase II), and Operation phase (Phase III). The MIU Project has been ongoing the Phase II and the Phase III in 2011 fiscal year. This report shows the results of the investigation, construction and collaboration studies in fiscal year 2011, as a part of the Phase II and Phase III based on the MIU Master Plan updated in 2010.

Planning of in-situ experiment for understanding of gas migration behaviour in sedimentary rock, 2; Affects of dissolved methane to the gas migration in bedrock

Tanai, Kenji; Fujita, Tomoo; Sato, Shin*; Noda, Masaru*; Yamamoto, Shuichi*; Shimura, Tomoyuki*

Dai-13-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.173 - 178, 2013/01

Japan Atomic Energy Agency has been planning gas migration test in Horonobe URL, Hokkaido. It is expected that dissolved methane in Horonobe groundwater might have an effect on gas migration behaviour in bedrock. A series of two-phase multi-component analyses by use of GETFLOWS were conducted to understand the influence of dissolved methane. The increase of total gas pressure has been shown due to the existence of dissolved methane. The results also indicated that the injected nitrogen gas volume was influenced by dissolved methane.

Excavation analysis of vertical shaft in sedimentary rock taken into account strain softening and depth variation of rock properties

Sanada, Hiroyuki; Matsui, Hiroya; Ogawa, Toyokazu*; Kinomura, Koji*; Aoki, Tomoyuki*; Yamamoto, Takuya*

JAEA-Research 2009-050, 57 Pages, 2010/01

JAEA-Research-2009-050.pdf:8.14MB

It is important to understand EDZ in assessing performance of repository and designing of plug. It is known that it remains possible that the large-scale EDZ is generated due to strain localization from boring investigations and tunnel excavation analyses and rock properties changes with increase of depth. Excavation analysis of vertical shaft in sedimentary rock taken into account strain softening, depth variation of rock properties and the actual construction procedure had been done in order to understand EDZ of Horonobe URL. The large-scale EDZ due to strain localization was generated around the border between Koetoi formation and Wakkanai formation. From result obtained from excavation analysis, scale of EDZ obtained from excavation analysis is from 60 cm to 120 cm. And it was estimated that seismic velocity changed by 20 percent, elastic modulus changed by 30 percent and hydraulic conductivity changed by 0.1 m/s order.

Long-term behaviors of a tuunel in a sedimentary soft rock due to fluid-mechanical interaction

Aoki, Tomoyuki*; Sanada, Hiroyuki; Jo, Mayumi*; Yamamoto, Takuya*; Matsui, Hiroya

Dai-12-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (CD-ROM), p.709 - 716, 2008/09

Long-term behaviors of a tunnel at great depth in sedimentary soft rocks are investigated based on pore fluid-mechanical interaction. Poroelastic parameters of diatomaceous and siliceous mudstones at the Horonobe URL site are determined from the tests proposed in this study using a triaxial test apparatus. The test procedures with their theoretical base are described. Coupled fluid-mechanical behaviors on circular and horse-shoe-shaped tunnels supported with shotcrete are numerically analyzed based on the theory of poroelasticity. Some long-term behaviors of rocks and supports peculiar to the fluid-mechanical interaction differing from creep behavior are found from the analysis results.

Evaluation on stability of shaft during excavation, considerating strain softening behavior surrounding rock mass

Kinomura, Koji*; Ogawa, Toyokazu*; Aoki, Tomoyuki*; Yamamoto, Takuya*; Matsui, Hiroya; Sanada, Hiroyuki

Dai-37-Kai Gamban Rikigaku Ni Kansuru Shimpojiumu Koen Rombunshu (CD-ROM), p.307 - 312, 2008/01

no abstracts in English

Consideration on poroelastic behavior of siliceous rock mass around an opening by stress-seepage coupled analysis

Sanada, Hiroyuki; Matsui, Hiroya; Yamamoto, Takuya*; Aoki, Tomoyuki*; Ogawa, Toyokazu*; Jo, Mayumi*; Fujii, Yoshiaki*

Heisei-19-Nendo Shigen, Sozai Gakkai Hokkaido Shibu Sokai Oyobi Shunki Koenkai Koen Yoshishu, p.9 - 10, 2007/06

Japan Atomic Energy Agency has been conducting the Horonobe Underground Reseach Laboratory Project as a part of geological isolation research and development at Horonobe-town in Hokkaido, Japan. The rocks around URL have high porosity and low permeability. Therefore, the excess pore pressure caused by URL excavation is possible to affect to the stability of surrounding rock. In this point of view, the authors carried out a stress-seepage coupled analysis to understand the process of the pore pressure change due to excavation and the influence to the stability of surrounding rock and support system. As a result, the large excess pore pressure causes a part in surrounding rock on excavation in an anisotropic initial stress condition and it dissipates with time. The pore pressure change causes the complex deformation in the surrounding rock as well. However, the phenomena are not significant influence to the stability of the surrounding rock and support system.

First principles study of core-hole effect on fluorine K-edge X-ray absorption spectra of MgF and ZnF

Yamamoto, Tomoyuki*; Mizoguchi, Teruyasu*; Tatsumi, Kazuyoshi*; Tanaka, Isao*; Adachi, Hirohiko*; Muramatsu, Yasuji; Gullikson, E. M.*; Perera, R. C. C.*

Materials Transactions, 45(7), p.1991 - 1993, 2004/07

https://doi.org/10.2320/matertrans.45.1991

First principles calculations have been carried out to investigate the core-hole effects on the theoretical fine structures of the X-ray absorption spectra of MgF and ZnF ath FK-edge. Experimental profiles of the near-edge X-ray absorption fine structures are well reproduced by the theoretical calculations when the core-hole effect is introduced. The dependence of supercell size on the theoretical fine structures is also examined.

Magnetic properties of URhGa and UFeGa

Ikeda, Shugo; Okubo, Tomoyuki*; Inada, Yoshihiko*; Tokiwa, Yoshifumi; Kaneko, Koji; Matsuda, Tatsuma; Yamamoto, Etsuji; Haga, Yoshinori; Onuki, Yoshichika

Journal of Physics; Condensed Matter, 15(28), p.S2015 - S2018, 2003/07

https://doi.org/10.1088/0953-8984/15/28/317

no abstracts in English