Paleoclimatic controls on natural tracer profiles in biogenic sedimentary formations of the Horonobe area, Japan

Arthur, R.*; Sasamoto, Hiroshi; Alt-Epping, P.*; Tachi, Yukio

Applied Geochemistry, 155, p.105707_1 - 105707_8, 2023/08

https://doi.org/10.1016/j.apgeochem.2023.105707

The experience gained in modeling the evolution, from past to present, of natural tracer profiles in geologic media can help support safety assessment of disposal concepts for radioactive wastes in deep geologic repository. Solute-transport models were developed in the present study using a forward modeling approach constrained by boundary conditions inferred from the paleo-hydrogeological evolution of the Horonobe area in Hokkaido, Japan. Apparent differences in transport behavior at the two boreholes location considered in this study, which were situated only about 1 km apart, appear to have resulted from relatively small differences in accessible porosity and hydraulic conductivity, which in turn may have been controlled by local differences in fracture density and fracture connectivity.

The Preliminary tests of the plasma melting treatment for homogenization of low-level radioactive wastes

Nakashio, Nobuyuki*; Osugi, Takeshi; Kurosawa, Shigenobu; Ishikawa, Joji; Hemmi, Ko; Iketani, Shotaro; Yokobori, Tomohiko

JAEA-Technology 2022-016, 47 Pages, 2022/08

JAEA-Technology-2022-016.pdf:2.23MB

The Nuclear Science Research Institute (NSRI) of the Japan Atomic Energy Agency (JAEA) started operation of the Advanced Volume Reduction Facilities (AVWF) for production of waste packages for disposal of low-level radioactive solid wastes (LLW). To clarify the operating conditions for homogenization of non-metallic LLW, preliminary tests were carried out using the plasma melting furnace of the non-metal melting unit. The fluidity of molten waste influences homogenization conditions of solidified products. It was clarified that the viscosity, which is determined by the chemical composition and the melting temperature, influence the fluidity of molten waste greatly through previous literature review and the small-scale melting tests. In the preliminary tests, the simulated waste with a cold tracer loaded in 200 L drums were melted. Using the waste chemical components (basicity, iron oxide concentration) as an experimental parameter, the homogeneity of the chemical components of the solidified product was investigated and the homogenization conditions of melting tests were examined. The retention ratio of the tracer in the molten bath was also confirmed. The viscosity of the molten wastes was measured and the correlation with homogeneity was examined. In addition, the technical requirements that should be concerned in advance for future actual operation were discussed.

Data of tracer migration test and borehole investigations for fracture zone in the Wakkanai formation at Horonobe Underground Research Laboratory

Tsushima, Masahito*; Takeda, Masaki; Ono, Hirokazu

JAEA-Data/Code 2018-008, 78 Pages, 2018/10

JAEA-Data-Code-2018-008.pdf:6.73MB
JAEA-Data-Code-2018-008(errata).pdf:0.11MB
JAEA-Data-Code-2018-008-appendix(DVD-ROM).zip:263.67MB

Japan Atomic Energy Agency (JAEA) has been conducting "geoscientific study" and "research and development on geological disposal" in the Horonobe Underground Research Laboratory (URL). In-situ tracer migration test for fracture and matrix in the argillaceous rock, called for Wakkanai formation, has been conducted in the Horonobe URL project. This report summarizes data of borehole investigations and tracer migration test for fracture zone.

Dipole tracer migration and diffusion tests in fractured sedimentary rock at Horonobe URL

Tanaka, Shingo*; Yokota, Hideharu; Ono, Hirokazu; Nakayama, Masashi; Fujita, Tomoo; Takiya, Hiroaki*; Watanabe, Naoko*; Kozaki, Tamotsu*

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 6 Pages, 2015/05

CFC indicating renewal of the Japan Sea deep water in winter 2000-2001

Tsunogai, Shizuo*; Kawada, Kentaro*; Watanabe, Shuichi*; Aramaki, Takafumi

Journal of Oceanography, 59(5), p.685 - 693, 2003/10

https://doi.org/10.1023/B:JOCE.0000009597.33460.d7

The water column distributions of CFC (chlorofluorocarbon) were determined twice in 2000 and 2001 in the northwestern Japan Sea. In 2000, the CFC-11 concentration decreased almost exponentially with depth from 6 pmol/kg at a few hundred m deep to 0.3 pmol/kg or less at the bottom of about 3400 m depth at 3 stations about 300 km off Vladivostok. In 2001, the CFC-11 concentration increased extremely up to 2 pmol/kg in the bottom water, while it did not increase at a station about 450 km away to the northeast. This is due to the renewal of the bottom water replaced by the surface water flowing down along the continental slope. The increase in the CFC-11 concentration was observed even in the whole water column above 3000 m depth. The increase in inventory is almost four times larger than that in the bottom water below 3000 m depth and equals about 1/6 of the total inventory found in 2000. The increase also means that 3 % of the deep water was replaced by the recent surface water or the turnover time of the deep water to be about 30 years, if the turnover occurs every year.

Vanadium uptake and an effect of vanadium treatment on F-labeled water movement in a cowpea plant by positron emitting tracer imaging system (PETIS)

Furukawa, Jun*; Yokota, Harumi*; Tanoi, Keitaro*; Ueoka, Shiori*; Matsuhashi, Shimpei; Ishioka, Noriko; Watanabe, Satoshi; Uchida, Hiroshi*; Tsuji, Atsunori*; Ito, Takehito*; et al.

Journal of Radioanalytical and Nuclear Chemistry, 249(2), p.495 - 498, 2001/08

https://doi.org/10.1023/A:1013276224300

We present real time Vanadate (V) uptake imaging in a cowpea plant by Positron Emitting Tracer Imaging System (PETIS). Vanadium-48 was produced by bombarding a Sc foil target with 50 MeV -particles at Takasaki Ion accelerators for Advanced Radiation Application (TIARA) AVF cyclotron. Then V was added to the culture solution to investigate the V distribution in a cowpea plant. The real time uptake of the V was monitored by PETIS. We measured the distribution of V in a whole plant after 3, 6 and 20 hours of V treatment by Bio-imaging Analyzer System (BAS). After the 20 hour treatment, vanadate was detected at the up-ground part of the plant. To know the effect of V uptake on plant activity, F-labeled water uptake was analyzed by PETIS. When a cowpea plant was treated with V for 20 hours before F-labeled water uptake experiment, the total amount of F-labeled water absorption was drastically desreased. Results suggest the inhibition of water uptake was mainly caused by the vanadate already moved to the up-ground part of the plant.

Melting behavior of low-level radioactive miscellaneous solid waste and characteristics of solidified products (Contract research)

Nakashio, Nobuyuki; Isobe, Motoyasu; Wakui, Takuji*; Iwata, Keiji*; Kibayashi, Tatsuyuki*; Kanazawa, Katsuo; Fukui, Toshiki; Otake, Atsushi*; Nakashima, Mikio; Hirabayashi, Takakuni*

JAERI-Research 2001-001, 19 Pages, 2001/02

JAERI-Research-2001-001.pdf:1.29MB

no abstracts in English

Fundamental experiments on accumulation behavior of molten fuel in a pressure vessel lower head

Shibamoto, Yasuteru; Nakamura, Hideo; Anoda, Yoshinari; Kukita, Yutaka*

JAERI-Tech 99-042, 41 Pages, 1999/05

JAERI-Tech-99-042.pdf:3.36MB

no abstracts in English

Estimation of longitudinal and transverse dispersivities in the Twin Lake natural gradient tracer tests

Takeda, Seiji; Moltyaner, G. L.*

JAERI-Research 98-031, 28 Pages, 1998/06

JAERI-Research-98-031.pdf:1.29MB

no abstracts in English

Experimental study on atmospheric tubulence and diffusion in a pine forest

Yamazawa, Hiromi; ; Chino, Masamichi; Hayashi, Takashi

Int. Workshop Proc., Improvement of Environmental Transfer Models and Parameters, 0, p.81 - 90, 1996/00

no abstracts in English