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.

Permeability measurement for macro-fractured granite using water including clay

Nara, Yoshitaka*; Kato, Masaji*; Sato, Tsutomu*; Kono, Masanori*; Sato, Toshinori

Proceedings of 5th ISRM Young Scholars' Symposium on Rock Mechanics and International Symposium on Rock Engineering for Innovative Future (YSRM 2019 and REIF 2019) (USB Flash Drive), 6 Pages, 2019/12

It is important to understand the long-term migration of radionuclides considering carious rock engineering projects such as the geological disposal of radioactive wastes. The network of fractures and pores in a rock mass can play important roles as the pathway of the fluid flow of rock. Usually groundwater contains fine-grained minerals such as clays. It is probable that the accumulation of the fine-grained minerals occurs in a fracture if the groundwater flows in a fracture in a rock. In this study, we have conducted the permeability measurement using water including clays. Specifically, we used a macro-fractured granite as a rock sample, and investigated the change of the permeability under the flow of the water including clays. It was shown that the hydraulic conductivity decreased with elapsed time.

Enhancement of permeability activated by supercritical fluid flow through granite

Nohara, Tsuyoshi; Uno, Masaoki*; Tsuchiya, Noriyoshi*

Geofluids, 2019, p.6053815_1 - 6053815_16, 2019/08

https://doi.org/10.1155/2019/6053815

Amphibole-plagioclase thermometry was applied to estimate the temperature of a glassy vein as approximately 700. The results of observations of the rock core revealed that of supercritical fluid flow was microfracture filling with hornblende and plagioclase. The current high permeability was recognized to be microfracture network. A high-angle fracture of chlorite filling in combination with an open fracture was recognized as characteristics of a high-permeability type.

An Evaluation of the long-term stagnancy of porewater in the neogene sedimentary rocks in northern Japan

Nakata, Kotaro*; Hasegawa, Takuma*; Oyama, Takahiro*; Ishii, Eiichi; Miyakawa, Kazuya; Sasamoto, Hiroshi

Geofluids, 2018, p.7823195_1 - 7823195_21, 2018/01

https://doi.org/10.1155/2018/7823195

A groundwater scenario is one of the scenario for safety assessment of geological disposal of high-level radioactive waste. In the safety assessment for groundwater scenario, the slow groundwater flow for a long-term should be an important factor. In the present study, study on stability of groundwater in the Koetoi and Wakkanai formations of Neogene marine based sedimentary rock at the Horonobe area, Hokkaido was performed by investigating the isotopes of chlorine and helium, and the stable isotopes of water. As the results, the stability of groundwater in deeper part of the Wakkanai formation was suggested due to no direct evidence of meteoric water intrusion during the uplift since ca. 1 Ma. Contrary, the groundwater both in the Koetoi formation and the upper Wakkanai formation would be unstable because the meteoric water intrusion was suggested by paleohydrogeological condition and the results of groundwater dating. Likely the Horonobe area, the accurate dating of groundwater would be difficult due to the complex effects of upward and mixing water derived from diagenesis in the thick sediment formation. However, a comparative procedure using both the results of groundwater dating and paleohydrogeological information would be useful for general evaluation of groundwater flow conditions for the long-term (i.e., check the possibility for long-term stability of groundwater).

Experimental and modeling study on long-term alteration of compacted bentonite with alkaline groundwater

Yamaguchi, Tetsuji; Sakamoto, Yoshifumi; Akai, Masanobu; Takazawa, Mayumi; Iida, Yoshihisa; Tanaka, Tadao; Nakayama, Shinichi

Physics and Chemistry of the Earth, 32(1-7), p.298 - 310, 2007/00

https://doi.org/10.1016/j.pce.2005.10.003

Dissolution rate of montmorillonite, diffusivity of hydroxide ion and permeability coefficient in compacted sand-bentonite mixtures were experimentally determined and formulated. A coupled mass-transport/chemical-reaction code was developed to predict variation in permeability of engineered bentonite barrier with alkaline fluid by using the formulae.

Preparation and characterization of chemically stable polymer electrolyte membranes by radiation-induced graft copolymerization of four monomers into ETFE films

Chen, J.; Asano, Masaharu; Yamaki, Tetsuya; Yoshida, Masaru

Journal of Membrane Science, 269(1-2), p.194 - 204, 2006/02

https://doi.org/10.1016/j.memsci.2005.06.035

To develop a highly chemically stable polymer electrolyte membrane for application in a direct methanol fuel cell (DMFC), four styrene derivative monomers, m,p-methylstyrene (MeSt), p-tert-butylstyrene (tBuSt), divinylbenzene (DVB) and bis(p,p-vinyl phenyl) ethane (BVPE) were graft copolymerized into poly(ethylene-co-tetrafluoroethylene) (ETFE) films followed by sulfonation and hydrolysis. The latter two monomers were used as crosslinkers. The graft copolymerization was carried out by the -ray preirradiation method. The influence of the preirradiation dose and the grafting kinetics were investigated in detail. Sulfonation of the grafted ETFE films was performed in a chlorosulfonic acid solution, by which the sulfonation ratio reached about 90%. The newly obtained membrane possesses significantly higher chemical stability than the traditional styrene/DVB-grafted membrane and six times lower methanol permeability compared to the Nafion 112 membrane. Therefore, this study reveals the possibility of the developed inexpensive four monomers-grafted membranes, which could provide an attractive alternative as a substitute for the expensive Nafion membranes for DMFC applications.

Counter-permeation of deuterium and hydrogen through INCONEL 600

Takeda, Tetsuaki; Iwatsuki, Jin*

Nuclear Technology, 146(1), p.83 - 95, 2004/04

https://doi.org/10.13182/NT04-A3490

The objective of this study is to investigate the effect of the existence of hydrogen in a pipe outside on the amount of permeated deuterium through the pipe. It was found that the amount of permeated deuterium decreases with increasing the partial pressure of hydrogen in the pipe outside when the partial pressure of deuterium in the pipe is lower than 100 Pa and that of hydrogen in the pipe outside is higher than 10 kPa. The amount of permeated deuterium on counter permeation was predicted quantitatively by using an effectiveness factor for diffusivity of deuterium in metals and by taking into account the equilibrium state for hydrogen, deuterium and HD molecules on the metal surface. From the results obtained in this study, it is supposed that the amount of tritium transferred from the primary circuit of the HTTR to the hydrogen production system will be reduced by the existence of high-pressure hydrogen in the catalyst pipe of the steam reformer.

Study on hydrogen isotope permeation in the HTTR hydrogen production system, 2; Effectiveness of reducing the amount of permeated deuterium by oxidized film (Contract research)

Takeda, Tetsuaki; Iwatsuki, Jin*; Nishihara, Tetsuo

JAERI-Tech 2002-090, 30 Pages, 2002/11

JAERI-Tech-2002-090.pdf:5.44MB

Permeation of hydrogen isotope through a high-temperature alloy as used a heat transfer pipe of an intermediate heat exchanger and a steam reformer is an important problem in the hydrogen production system connected to be the high-temperature engineering test reactor (HTTR). In order to obtain detailed data for safety review and development of analytical codes, a test of permeation of hydrogen isotope was carried out as one of essential tests. The objective of this study is to obtain a permeability of hydrogen isotope through Hastelloy XR and other high temperature alloys and to evaluate quantitatively an effect of oxidized film on reducing the amount of permeated hydrogen through the pipe. From the results obtained in this experiment, it is supposed that the oxidized film produced on the surface of the heat transfer pipe during an early stage of the reactor operation will reduce the amount of tritium permeated from the primary circuit of the HTTR to the utilization system.

Measurement of HTO permeability parameters of materials for protective appliances

Yokoyama, Sumi; Noguchi, Hiroshi; Kinouchi, Nobuyuki; Yamamoto, Hideaki; Kato, Shohei; *; *

Hoken Butsuri, 34(1), p.57 - 66, 1999/00

https://doi.org/10.5453/jhps.34.57

no abstracts in English

Measurement of HTO permeability of materials for protective appliances

Yamamoto, Hideaki; *; Kato, Shohei; Murata, Mikio; Kinouchi, Nobuyuki;

Proc. of the Int. Radiation Protection Association,Vol. 1, p.467 - 470, 1992/00

no abstracts in English