Thermochronology of hydrothermal alteration zones in the Kii Peninsula, southwest Japan; An Attempt for detecting the thermal anomalies and implications to the regional exhumation history

Sueoka, Shigeru; Iwano, Hideki*; Danhara, Toru*; Niwa, Masakazu; Kanno, Mizuho; Kohn, B. P.*; Kawamura, Makoto; Yokoyama, Tatsunori; Kagami, Saya; Ogita, Yasuhiro; et al.

Earth, Planets and Space (Internet), 75(1), p.177_1 - 177_24, 2023/12

https://doi.org/10.1186/s40623-023-01921-5

Fluid-inclusion and thermochronometric analyses have been applied to hydrothermal alteration zones and their host rocks outcropping in the Hongu area of the Kii Peninsula, southwestern Japan in an attempt to detect thermal anomalies related to hydrothermal events and quantify the thermal effects on the host rocks. Hydrothermal events at ca 150 deg. C and ca 200 deg. C were identified by fluid-inclusion microthermometry of quartz veins in the alteration zones. For the host rocks and alteration zones, in the youngest population zircon yielded U-Pb dates ranging between ca 74.7-59.2 Ma, fission-track dates of ca 27.2-16.6 Ma, and (U-Th)/He single-grain dates of ca 23.6-8.7 Ma. Apatite yielded pooled fission-track ages of ca 14.9-9.0 Ma. The zircon U-Pb dates constrain the maximum depositional ages of the sedimentary samples. However, the fission-track and (U-Th)/He dates show no clear trend as a function of distance from the alteration zones. Hence, no thermal anomaly was detected in the surrounding host rocks based on the thermochronometric data patterns. The fission-track and (U-Th)/He dates are rather thought to record regional thermal and exhumation histories rather than a direct thermal imprint of fluid flow, probably because the duration of such activity was too short or because fluid flow occurred before regional cooling events and were later thermally overprinted. Apatite fission-track ages of ca 10 Ma may reflect regional mountain uplift and exhumation related to the obduction of the SW Japan lithospheric sliver onto the Shikoku Basin, or the rapid subduction of the Philippine Sea slab associated with the clockwise rotation of the Southwest Japan Arc.

Status of neutron spectrometers at J-PARC

Kajimoto, Ryoichi; Yokoo, Tetsuya*; Nakamura, Mitsutaka; Kawakita, Yukinobu; Matsuura, Masato*; Endo, Hitoshi*; Seto, Hideki*; Ito, Shinichi*; Nakajima, Kenji; Kawamura, Seiko

Physica B; Condensed Matter, 562, p.148 - 154, 2019/06

BB2018-0526.pdf:2.45MB

https://doi.org/10.1016/j.physb.2018.11.061

Inelastic and quasi-elastic neutron scattering spectrometers in J-PARC

Seto, Hideki; Ito, Shinichi; Yokoo, Tetsuya*; Endo, Hitoshi*; Nakajima, Kenji; Shibata, Kaoru; Kajimoto, Ryoichi; Kawamura, Seiko; Nakamura, Mitsutaka; Kawakita, Yukinobu; et al.

Biochimica et Biophysica Acta; General Subjects, 1861(1), p.3651 - 3660, 2017/01

https://doi.org/10.1016/j.bbagen.2016.04.025

J-PARC, Japan Proton Accelerator Research Complex provides short pulse proton beam at a repetition rate 25 Hz and the maximum power is expected to be 1 MW. Materials and Life Science Experimental Facility (MLF) has 23 neutron beam ports and 21 instruments have already been operated or under construction / commissioning. There are 6 inelastic / quasi-elastic neutron scattering spectrometers and the complementary use of these spectrometers will open new insight for life science.

Nanoscale diffusion tracing by radioactive Li tracer

Ishiyama, Hironobu*; Jeong, S.-C.*; Watanabe, Yutaka*; Hirayama, Yoshikazu*; Imai, Nobuaki*; Miyatake, Hiroari*; Oyaizu, Mitsuhiro*; Katayama, Ichiro*; Osa, Akihiko; Otokawa, Yoshinori; et al.

Japanese Journal of Applied Physics, 53(11), p.110303_1 - 110303_4, 2014/11

https://doi.org/10.7567/JJAP.53.110303

Study on numerical simulation of bubble and dissolved gas behavior in liquid metal flow

Ito, Kei; Ohno, Shuji; Kamide, Hideki; Kogawa, Hiroyuki; Futakawa, Masatoshi; Kawamura, Takumi*; Imai, Yasutomo*

JAEA-Research 2013-008, 117 Pages, 2013/10

JAEA-Research-2013-008.pdf:6.55MB

The Japan Atomic Energy Agency has been developed a plant dynamics code VIBUL to simulate the concentration distributions of the dissolved gas and the bubbles in a fast reactor. In this study, the VIBUL code is improved to achieve accurate simulations, e.g. rigorous mole conservation of inert gas. Moreover, new modles are introduced to simulate the small bubble behaviors in the J-PARC mercury target system. To validate the improved models and the newly developed models, the inert gas behaviors in the large-scale sodium-cooled reactor and the small bubble behaviors are simulated. As a result, it is confirmed that the complicated bubble dynamics in each component, e.g. core, IHX or surge tank, can be simulated appropriately by the VIBUL code.

Origin and chemical speciation of anthropogenic Iodine-129

Shima, Shigeki*; Gasa, Shinichi*; Amano, Hikaru; Nagao, Seiya*; Yamamoto, Masayoshi*; Momoshima, Noriyuki*; Furukawa, Masahide*; Kimura, Hideki*; Kawamura, Hisao*

JAEA-Conf 2008-003, p.28 - 31, 2008/04

https://jopss.jaea.go.jp/pdfdata/JAEA-Conf-2008-003.pdf

Concentrations of I in surface seawater around Japan were approximately 210atoms/L in literatures. However, the atomic ratio of iodine to cesium was ten times as high as that of the global fallout. The origin of I in the water columns seems to be difficult to be explained by only the global fallout. Discharge from European plants was one of the possible origins of iodine from the standpoint of air mass trajectory analysis. Concentration of I in rain water was 10 times higher than that in surface seawater. Anthropogenic inorganic iodine in surface seawater predominantly dissolves as an iodide ion (I).

The H-Invitational Database (H-InvDB); A Comprehensive annotation resource for human genes and transcripts

Yamasaki, Chisato*; Murakami, Katsuhiko*; Fujii, Yasuyuki*; Sato, Yoshiharu*; Harada, Erimi*; Takeda, Junichi*; Taniya, Takayuki*; Sakate, Ryuichi*; Kikugawa, Shingo*; Shimada, Makoto*; et al.

Nucleic Acids Research, 36(Database), p.D793 - D799, 2008/01

https://doi.org/10.1093/nar/gkm999

Here we report the new features and improvements in our latest release of the H-Invitational Database, a comprehensive annotation resource for human genes and transcripts. H-InvDB, originally developed as an integrated database of the human transcriptome based on extensive annotation of large sets of fulllength cDNA (FLcDNA) clones, now provides annotation for 120 558 human mRNAs extracted from the International Nucleotide Sequence Databases (INSD), in addition to 54 978 human FLcDNAs, in the latest release H-InvDB. We mapped those human transcripts onto the human genome sequences (NCBI build 36.1) and determined 34 699 human gene clusters, which could define 34 057 protein-coding and 642 non-protein-coding loci; 858 transcribed loci overlapped with predicted pseudogenes.

Alternative repository design concepts for HLW disposal; Challenges and initiatives

Masuda, Sumio*; Kawamura, Hideki*; McKinley, I. G.*; Kitayama, Kazumi*; Umeki, Hiroyuki

Proceedings of Radioactive Waste Management; The Next Step: Confidence, Safety and Implementation, 8 Pages, 2006/06

Many of the "standard" designs for deep geological radwaste repositories were developed decades ago and have altered little since. Changing boundary conditions - both technical and socio-economic - are driving increasing interest in the consideration of alternatives, particularly for disposal of higher activity and longer-lived wastes. This was particularly the case in Japan, following the decision by NUMO to proceed with site selection based on a volunteering process. The work by NUMO to examine alternatives provides a good illustration of the range of possibilities which are available to allow flexible tailoring of design to fit both the characteristics of volunteer sites and the desires of local communities. On an even larger scale, however, the 21st century can be expected to bring challenges that will affect the future nuclear power generation at both national and global levels. As repository project are planned and implemented over timescales of many decades, such uncertainties should be taken into account to ensure that waste disposal projects initiated now remain appropriate to the future generations who will build, operate and close them.

Optimising repository design for the CARE concept

Masuda, Sumio*; Kawamura, Hideki*; McKinley, I. G.*; Neall, F. B.*; Umeki, Hiroyuki

Proceedings of 11th International High-Level Radioactive Waste Management Conference (IHLRWM) (CD-ROM), p.507 - 514, 2006/00

There has been increasing international interest in repository designs, particularly for high-level radioactive waste (HLW) or spent fuel (SF), which maintain the option of ease of retrieval for long periods of time. Such delayed closure may be driven by either a need to slowly gain social acceptance or a desire to maintain the future option of reprocessing of spent fuel in view of the resurgence of interest in nuclear power. In either case, there are advantages in repository concepts which are specifically developed with this requirement in mind, rather than attempting to modify designs developed under different boundary conditions. The CARE concept is an example of such a design. In the present paper, the basic concept is outlined and examined with respect to optimisation of both operational and post-closure safety.

Information Collection and Analysis of Geological Characterization and Evaluation Technology and Application to Geological Characterization Study

Kawamura, Hideki*; Noda, Masaru*; Nishikawa Naohito*; Sato, Shoko*; Tanaka, Tatsuya*

JNC TJ7410 2003-002, 515 Pages, 2003/03

JNC-TJ7410-2003-002.pdf:25.77MB

Tono Geoscience Center (TGC) of Japan Nuclear Cycle Development Institute has been conducting the Regional Groundwater Investigation and Mizunami Underground Laboratory (MIU) Project in order to develop investigation technologies and evaluation methods of geological environment. At present, towards the next progeress reporting on research and development for geological disposal of HLW in Japan, based on the existing research and development results, the Projects which are conducted at Tono Geoscience Center are required for promoting the MIU program smoothly and effeciently with regard to the current Japanese HLW program. According to such situation, for planning of the geological environment investigation and research at TGC and the next progress reporting, this study has investigated and summarizes overseas environmental impact assessments for final disposal, overseas site characterization and site selection, and overseas research plan of underground research laboratories. Based on the results of investigation, some technologies which have possibility to be applied to the MIU Project have been studied. Also overseas quality assurance programs have been investigated, and examples of the application of their concepts to MIU project have been considered.