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Futakuchi, Katsuhito*; Hiroki, Minenari*; Sakuramoto, Yuji*
JNC TJ8400 2004-010, 33 Pages, 2004/02
The alteration characteristics of volcanic glass in geological medium are investigated as natural analogues of geological disposal of high-level radioactive wastes. This study leads to the following conclusion. The activation energy was calculated for changes from volcanic glasses to clinoptilolite is 176.27KJ/mol.
Wakahama, Hiroshi*; Nakata, Mitsuhiko*; Hiroki, Minenari*; Futakuchi, Katsuhito*; Okada, Akio*
JNC TJ7440 2003-004, 128 Pages, 2003/03
This report describes the results of installation of the long-term groundwater monitoring system into borehole DH-2 as a part of the Regional Hydrogeological Study and Mizunami Underground Research Laboratory Project. DH-2 was driglled with 100mm diameter through Toki-granite to the depth of 501meter below the ground level, in which 5inch-steel-casing pipe was inserted to the depth of 171m. The monitoring system was composed of concentrically arranged seven open PVC(polyvinyl chloride)-stand-pipes("Piezo-pipes"), housed within outer 4inch PVC-casings, followed by 3inch PVC-casings, packers and several stainless steel units. In the system, seven monitoring zones were isolated by expandable rubber type packers inflating with water. From the view point of quality assessment, leak-off tests were conducted for all of 7 packers before the shipment and the installation at the site. In terms of individual casing joints, air-tight inspections were carried out ...
Futakuchi, Katsuhito*; Sakuramoto, Yuji*; Hiroki, Minenari*
JNC TJ8400 2003-006, 50 Pages, 2003/01
The alteration characteristics of volcanic glass and bentonite in geological medium are investigated as natural analogues of geological disposal of high-level radioactive wastes. For the study of alterlation of volcanic glass, literature survey, petrographical observation by using optical microscope, chemical analysis of pore water and groundwater, and microbiostratigraphical study were carried out. The volcanic ashes were collected from a borehole, which had been drilled in the Kanto region by the National Research Institute for Earth Science and Disaster Prevention. The volcanic glass was wholly altered in thin sections. Chemical analysis of pore water indicate the chloride-rich composition. And chemical analysis of groundwater, which are pumped up near the studied borehole, indicate the mixing product of connate marine water and fresh groundwater. Fossil evidence suggests that the studied volcanic glass is 3.654.2Ma. in age, and is correlated with upper Miura Group. This study leads to the following conclusion. The volcanic glass, under the temperature condition 70C, was wholly altered to montomorillonite and clinoptilolite. This case must be occurred in the connate marine water at last 0.5 Ma..
Futakuchi, Katsuhito*; Sakuramoto, Yuji*; Hiroki, Minenari*
JNC TJ8400 2001-046, 61 Pages, 2002/02
The alteration characteristics of volcanic glass and bentonite in geological medium are investigated as natural analogues of geological disposal of high-level radioactive wastes. For the study of volcanic glass, volcanic ashes are collected from boreholes, which were drilled in the Kanto region by the National Research Institute for Earth Science and Disaster Prevention. The volcanic glass, under the temperature condition 70C, was altered to montomorillonite and clinoptilolite, but another volcanic glass, under the temperature condition up to 50C, was not altered. Both cases may be occurred in the connate marine water at last 0.5 Ma For the study of bentonite, slight alkaline hot spring water (pH: up to 9) and rocks in Rausu area, Hokkaido Prefecture, have been studied to examine the zeolitization of montmorillonite. X-ray diffraction analysis show that montmorillonite, kaolinite, mordenite, and alunite were recognized as the alteration minerals. Alkaline (pH:up to 9) and high temperature (about 90C) water (Na - Cl type) were found at several outcrops, chemical and isotopic analysis show that those alkali hot spring waters were meteoric origin, increasing of salinity were as a result of seepage through the marine sedimentary strata, and high temperature was derived from the heat source. Stability relationship for system anorthite - kaolinite - montmorillonite - silica minerals - aqueous solution shows that montmorillonite was stable in those spring water.