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Journal Articles

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

 Times Cited Count:0 Percentile:0.01(Geochemistry & Geophysics)

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.

Journal Articles

Permeability measurement for macro-fractured Horonobe mudstone

Kamata, Kento*; Nara, Yoshitaka*; Matsui, Hiroya; Ozaki, Yusuke

Dai-15-Kai Iwa No Rikigaku Kokunai Shimpojiumu Koen Rombunshu (Internet), p.205 - 209, 2021/01

When considering the projects such as radioactive waste disposal, it is important to evaluate the confinement performance of underground substances in rock mass. However, the change in permeability of macro-fractured mudstone has not been sufficiently studied. Therefore, in this study, we investigated its effect on permeability by introducing a macro-fracture into a cylindrical specimen of mudstone distributed in the Horonobe area, Hokkaido. First, the hydraulic conductivity was measured by subjecting a specimen with a macro-fracture introduced by a brazilian test to a falling head permeability test. After that, it was compared with the hydraulic conductivity of the intact specimen measured by the transient pulse method. As a result, it was confirmed that the hydraulic conductivity was increased by about one order due to the introduction of macro-fracture. The increase rate of hydraulic conductivity obtained from the results of this research was smaller than that of previous researches using granite and basalt.

Journal Articles

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.

Journal Articles

The Effect of dissolved gas on rock desaturation in artificial openings in geological formations

Miyakawa, Kazuya; Aoyagi, Kazuhei; Sasamoto, Hiroshi; Akaki, Toshifumi*; Yamamoto, Hajime*

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

The construction and operation of geological repositories require excavation and ventilation of galleries, with significant groundwater drainage. Desaturation of rock around galleries is unavoidable and may affect hydraulic properties and redox conditions. This study used numerical modeling to assess the influence of dissolved gas on the degree of saturation of rock surrounding excavated galleries, focusing on siliceous mudstone rock in the 140 m, 250 m, and 350-m-deep galleries of the Horonobe Underground Research Laboratory, Japan. Based on previous ${it in situ}$ electrical survey, the degree of saturation in the 250 m gallery was higher than that in the 140 m and 350 m galleries. In the Horonobe area, deep groundwater contains high concentrations of dissolved methane, and exsolution of this methane from pore water can affect desaturation. Simple numerical modeling, including simulation of multiphase flows, was undertaken for each gallery to confirm the effect of dissolved gas and rock permeability on desaturation. A sensitivity analysis was performed by varying dissolved gas contents and permeability. Results indicate that the dissolved gas content affects both the degree of saturation and its spatial extent, whereas rock permeability affects only the latter. Higher dissolved gas concentrations result in lower degrees of saturation with a greater spatial extent of desaturation, and higher permeability leads to greater extents of desaturation. It is therefore likely that gas content, rather than rock permeability, caused the observed variations in the saturation degree.

Journal Articles

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

 Times Cited Count:3 Percentile:31.47(Geochemistry & Geophysics)

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.

Journal Articles

Application of transient pulse method to permeability measurement for clay

Kato, Masaji*; Nara, Yoshitaka*; Okazaki, Yuki*; Kono, Masanori*; Sato, Toshinori; Sato, Tsutomu*; Takahashi, Manabu*

Zairyo, 67(3), p.318 - 323, 2018/03

To ensure the safe geological disposal of radioactive wastes, it is important to determine the permeability of clays. The transient pulse test is suitable to apply to the low permeability materials, because it takes relatively short term to determine the permeability. Usually we increase the upstream pore pressure in the measurement with the transient pulse test. However, it is impossible to determine the permeability of clay in this procedure because of the increase of pore pressure. Therefore, the transient pulse test has never been applied to the determination of permeability of clays. In this study, we tried to apply the transient pulse test to a clay obtained in Mizunami Underground Research Laboratory to determine the permeability with decreasing the downstream pore pressure. It was clarified that the transient pulse test with decreasing downstream pore pressure is appropriate from the measurements of granite and sandstone. It was shown that the permeability of a clay was determined by the transient pulse test with decreasing the downstream pore pressure, which agreed with the permeability determined from the falling head test. The measurement time of the transient pulse test is much shorter than that of the falling head test. It is concluded that the transient pulse test is appropriate for the determination of the permeability of clays.

Journal Articles

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

 Times Cited Count:7 Percentile:50.42(Geochemistry & Geophysics)

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).

Journal Articles

Permeability estimation based on crack tensor on site scale

Yamasaki, Masanao*; Tsusaka, Kimikazu*; Otani, Tatsuhiko*; Shinji, Masato*

Doboku Gakkai Rombunshu, F2 (Chika Kukan Kenkyu) (Internet), 71(1), p.1 - 10, 2015/04

Japan Atomic Energy Agency has been constructed the Underground Research Laboratory in Hokkaido. In the shaft excavation, length, direction and aperture of geological observation are measured and analyzed in order to estimate rock permeability around lining. In this report, correlation between frequency of cracks and rock permeability based on crack tensor and stereology was discussed. Prediction equation of rock permeability from the frequency of cracks on the shaft wall was also proposed.

Journal Articles

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

 Times Cited Count:42 Percentile:73.3(Geosciences, Multidisciplinary)

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.

Journal Articles

Investigation of hydrogen isotope permeation through F82H steel with and without a ceramic coating of Cr$$_{2}$$O$$_{3}$$-SiO$$_{2}$$ including CrPO$$_{4}$$, Out-of-pile tests

Kulsartov, T. V.*; Hayashi, Kimio; Nakamichi, Masaru*; Afanasyev, S. E.*; Shestakov, V. P.*; Chikhray, Y. V.*; Kenzhin, E. A.*; Kolbaenkov, A. N.*

Fusion Engineering and Design, 81(1-7), p.701 - 705, 2006/02

 Times Cited Count:40 Percentile:92.29(Nuclear Science & Technology)

no abstracts in English

Journal Articles

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

 Times Cited Count:139 Percentile:96.15(Engineering, Chemical)

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 $$gamma$$-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.

Journal Articles

Critical $$beta$$ analyses with ferromagnetic and plasma rotation effects and wall geometry for a high $$beta$$ steady state tokamak

Kurita, Genichi; Bialek, J.*; Tsuda, Takashi; Azumi, Masafumi*; Ishida, Shinichi; Navratil, G. A.*; Sakurai, Shinji; Tamai, Hiroshi; Matsukawa, Makoto; Ozeki, Takahisa; et al.

Nuclear Fusion, 46(2), p.383 - 390, 2006/02

 Times Cited Count:9 Percentile:31.45(Physics, Fluids & Plasmas)

It is shown that critical beta is decreased by ferromagnetic effect by about 8% for $$mu$$/$$mu$$$$_{0}$$$$sim$$2, $$mu$$ and $$mu$$$$_{0}$$ denoting the permeability of ferromagnetic wall and vacuum, respectively, for tokamak of aspect ratio 3. The existence of the stability window for resistive wall mode opened by both effects of the toroidal plasma rotation and the plasma dissipation, which was not observed for high aspect ratio tokamak, is found for tokamak of aspect ratio 3. The effect of ferromagnetism on them is also investigated. The critical beta analyses of NCT (National Centralized Tokamak) plasma using VALEN code are started with stabilizing plate and vacuum vessel geometry with finite resistivity, and the results for passive effect of stabilizing plate are obtained. The calculations including stabilizing effect of the vacuum-vessel and also active feedback control are also performed for present design of NCT plasma.

Journal Articles

Counter-permeation of deuterium and hydrogen through INCONEL 600

Takeda, Tetsuaki; Iwatsuki, Jin*

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

 Times Cited Count:9 Percentile:52.9(Nuclear Science & Technology)

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.

Journal Articles

Permeability of hydrogen and deuterium of Hastelloy XR

Takeda, Tetsuaki; Iwatsuki, Jin*; Inagaki, Yoshiyuki

Journal of Nuclear Materials, 326(1), p.47 - 58, 2004/03

 Times Cited Count:19 Percentile:75.49(Materials Science, Multidisciplinary)

Permeation of hydrogen isotope through a high-temperature alloy used as heat exchanger and steam reformer pipes is an important problem in the hydrogen production system connected to be a High-Temperature Engineering Test Reactor (HTTR). An experiment of hydrogen (H$$_{2}$$) and deuterium (D$$_{2}$$) permeation was performed to obtain permeability of H$$_{2}$$ and D$$_{2}$$ of Hastelloy XR, which is adopted as heat transfer pipe of an intermediate heat exchanger of the HTTR. Permeability of H$$_{2}$$ and D$$_{2}$$ of Hastelloy XR were obtained as follows. The activation energy E$$_{0}$$ and pre-exponential factor F$$_{0}$$ of the permeability of H$$_{2}$$ was E$$_{0}$$=67.2$$pm$$1.2 kJ/mol and F$$_{0}$$=(1.0$$pm$$0.2)$$times$$10$$^{-8}$$m$$^{3}$$(STP)/m$$^{-1}$$/s$$^{-1}$$/Pa$$^{-0.5}$$, respectively, in the pipe temperature ranging from 843K-1093K.

JAEA Reports

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


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.

Journal Articles

A Steady-state simulation model of gas separation system by hollow-filament type membrane module

Iwai, Yasunori; Yamanishi, Toshihiko; Nishi, Masataka

Journal of Nuclear Science and Technology, 36(1), p.95 - 104, 1999/01

 Times Cited Count:12 Percentile:66.4(Nuclear Science & Technology)

no abstracts in English

Journal Articles

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

no abstracts in English

JAEA Reports


Miyake, Yasuhiro*

PNC TN9440 94-021, 84 Pages, 1994/09



Journal Articles

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

JAEA Reports

Waterproof effect of plastic coating on radioactive waste solids

*; *; *; *; Matsuzuru, Hideo

JAERI-M 89-200, 26 Pages, 1989/12


no abstracts in English

27 (Records 1-20 displayed on this page)