Annual report for research on geosphere stability for long-term isolation of radioactive waste in fiscal year 2022

Niwa, Masakazu; Shimada, Koji; Sueoka, Shigeru; Ishihara, Takanori; Ogawa, Hiroki; Hakoiwa, Hiroaki; Watanabe, Tsuyoshi; Nishiyama, Nariaki; Yokoyama, Tatsunori; Ogata, Manabu; et al.

JAEA-Research 2023-005, 78 Pages, 2023/10

JAEA-Research-2023-005.pdf:6.51MB

This annual report documents the progress of research and development (R&D) in the 1st fiscal year of the Japan Atomic Energy Agency 4th Medium- and Long-term Plan (fiscal years 2022-2028) to provide the scientific base for assessing geosphere stability for long-term isolation of high-level radioactive waste. The plan framework is structured into the following categories: (1) Development and systematization of investigation techniques, (2) Development of models for long-term estimation and effective assessment, (3) Development of dating techniques. The current status of R&D activities with previous scientific and technological progress is summarized.

Weyl-Kondo semimetal behavior in the chiral structure phase of CeRhSn

Iwasa, Kazuaki*; Suyama, Kazuya*; Kawamura, Seiko; Nakajima, Kenji; Raymond, S.*; Steffens, P.*; Yamada, Akira*; Matsuda, Tatsuma*; Aoki, Yuji*; Kawasaki, Ikuto; et al.

Physical Review Materials (Internet), 7(1), p.014201_1 - 014201_11, 2023/01

https://doi.org/10.1103/PhysRevMaterials.7.014201

Measurement of neutron scattering cross section of nano-diamond with particle diameter of approximately 5 nm in energy range of 0.2 meV to 100 meV

Teshigawara, Makoto; Tsuchikawa, Yusuke*; Ichikawa, Go*; Takata, Shinichi; Mishima, Kenji*; Harada, Masahide; Oi, Motoki; Kawamura, Yukihiko*; Kai, Tetsuya; Kawamura, Seiko; et al.

Nuclear Instruments and Methods in Physics Research A, 929, p.113 - 120, 2019/06

https://doi.org/10.1016/j.nima.2019.03.038

A nano-diamond is an attractive neutron reflection material below cold neutron energy. The total neutron cross section of a nano-diamond was derived from a neutron transmission measurement over the neutron energy range of 0.2 meV to 100 meV because total neutron cross section data were not available. The total cross section of a nano-diamond with particle size of approximately 5 nm increased with a decrease in neutron energy to 0.2 meV. It was approximately two orders of magnitude larger than that of graphite at 0.2 meV. The contribution of inelastic scattering to the total cross section was to be shown negligible small at neutron energies of 1.2, 1.5, 1.9, 2.6, and 5.9 meV in the inelastic neutron scattering measurement. Moreover, small-angle neutron scattering measurements of the nano-diamond showed a large scattering cross section in the forward direction for low neutron energies.

Tracing temperature in a nanometer size region in a picosecond time period

Nakajima, Kaoru*; Kitayama, Takumi*; Hayashi, Hiroaki*; Matsuda, Makoto; Sataka, Masao*; Tsujimoto, Masahiko*; Toulemonde, M.*; Bouffard, S.*; Kimura, Kenji*

Scientific Reports (Internet), 5, p.13363_1 - 13363_8, 2015/08

https://doi.org/10.1038/srep13363

"Relative rates method" for evaluating the effect of potential geological environmental change due to uplift/erosion to radionuclide migration of high-level radioactive waste

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

https://doi.org/10.1557/opl.2014.626

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.

Quantitative analysis of cisplatin sensitivity of human esophageal squamous cancer cell lines using in-air micro-PIXE

Tanaka, Naritake*; Kimura, Hitoshi*; Faried, A.*; Sakai, Makoto*; Sano, Takaaki*; Inose, Takanori*; Soda, Makoto*; Okada, Koji*; Nakajima, Masanobu*; Miyazaki, Tatsuya*; et al.

Cancer Science, 101(6), p.1487 - 1492, 2010/06

https://doi.org/10.1111/j.1349-7006.2010.01542.x

We examined the intracellular localization of cisplatin, a key chemotherapeutic agent, in esophageal cancer cell lines and determined their sensitivity to cisplatin using in-air micro-PIXE. Two human esophageal squamous cell carcinoma (ESCC) cell lines, TE-2 and TE-13, were examined for their response to cisplatin using MTT assay, flow cytometry and DNA fragmentation assays. Real-time reverse transcription-polymerase chain reaction was also used to evaluate the mRNA expression of multidrug resistance protein 2 (MRP2) in both cell lines. Platinum localizations of intracellular and intranuclear were measured using in-air micro-PIXE. TE-2 cells were more sensitive to cisplatin than TE-13 cells. The results of this study suggest that in-air micro-PIXE could be a useful quantitative method for evaluating the cisplatin sensitivity of individual cells. Finally, we speculate that MRP2 in the cell membrane may play an important role in regulating cisplatin sensitivity of ESCC cells.

Study on reciprocal relation of pore water pressure with genetic algorithm and neural network model(Contract research)

Seno, Shoji*; Kunimaru, Takanori; Nakajima, Makoto*; Toida, Masaru*; Watanabe, Kunio*; Sohail, A. R.*

JAEA-Research 2008-126, 120 Pages, 2009/12

JAEA-Research-2008-126.pdf:29.29MB

At first, to exclude the influences of working of nature such as tide and atmospheric pressure from the source data, an analysis with Bayesian model was progressed. As the result of the estimation of these influences calculated by BAYTAP-G (Bayesian Tidal Analysis Program Grouping Model), it was found that the influence of the atmospheric pressure was comparatively large and that of tide was comparatively small.

Illustration of an approach to evaluate the effect of the uplift and denudation for a groundwater scenario of a geological disposal concept in a hypothetical sedimentary rock

Ebashi, Takeshi; Kawamura, Makoto; Inagaki, Manabu; Koo, Shigeru*; Shibata, Masahiro; Itazu, Toru; Nakajima, Kunihiko*; Miyahara, Kaname

JAEA-Research 2008-117, 36 Pages, 2009/03

JAEA-Research-2008-117.pdf:3.18MB

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.

Development of three-dimensional virtual plant vibration simulator on grid computing environment ITBL-IS/AEGIS

Suzuki, Yoshio; Nakajima, Norihiro; Araya, Fumimasa; Hazama, Osamu; Nishida, Akemi; Kushida, Noriyuki; Akutsu, Taku; Teshima, Naoya; Nakajima, Kohei; Kondo, Makoto; et al.

Proceedings of 16th International Conference on Nuclear Engineering (ICONE-16) (CD-ROM), 9 Pages, 2008/05

Assessment of uncertainties associated with the characterization of the geological environment in the Tono Area -Japanese fiscal year, 2005- (Contract research)

Toida, Masaru*; Suyama, Yasuhiro*; Mori, Takayuki*; Inaba, Takeshi*; Atsumi, Hiroyuki*; Tanaka, Toshiyuki*; Kobayashi, Ichizo*; Nakajima, Makoto*; Ogata, Nobuhisa

JAEA-Research 2007-071, 159 Pages, 2007/09

JAEA-Research-2007-071.pdf:48.05MB

"Geoscientific research" at the Tono Area is developing site investigation, characterization and assessment techniques for understanding of geological environment. Their important goal is to establish a methodology for analyzing uncertainties in a heterogeneous geological environment and to develop investigation techniques for efficiently reducing the uncertainties. In Fiscal Year 17, in addition to information from the MIZ-1 borehole investigation, present knowledge has been compiled. The proposed technique has been improved through conceptual geological modeling and groundwater analyses at the Tono Area. Design options for handling geological uncertainties based on the characterization of the geological environment have also been tested. The results of this study can be summarized as follows: (1) It was shown that the fracture group with NW strike has high correlation with maximum measured transmissivity. This was maybe caused by the effect of regional in situ stress. (2) Through conceptual geological modelling and groundwater analysis, a procedure for modelling of the geological environment with heterogeneous characteristics was proposed. (3) From the viewpoint of improving the design of an underground facility, the existence of uncertainties of the geological environment with heterogeneous characteristics requests multiple options. A design option should be adapted to the geological environment with heterogeneous characteristics.