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Otagaki, Takao*; *
JNC TJ8420 2000-016, 427 Pages, 2000/03
JNC-TJ8420-2000-016.pdf:18.18MB
no abstracts in English
Sato, Toshinori; Taniguchi, Wataru; Fujita, Tomoo; Hasegawa, Hiroshi
JNC TN7400 99-011, 36 Pages, 1999/12
In order to understand the general thermal and mechanical properties of rock masses and initial stress of rock at depth, data were compiled from the published literature in Japan and collected from investigations carried out at Kamaishi mine and Tono mine. Statistical examinations derived the ranges, means and medians of the mechanical properties for the different rock types. It was confirmed that the correlations between the mechanical properties were in agreement with correlations determined previously in other similar surveys. The unconfined compressive strength of Neogene sedimentary rocks showed a tendency to increase with increasing depth (
500 m). An examination of the measured initial stress data collected through literature surveys showed that the vertical stress can be approximated by the extent of gravitational loading at a particular point. There is an approximately linear relationship between the average stress in a horizontal plane and the depth. The lateral pressure coefficient tends to have a high value and large range at shallow depths, but tends towards 
1 with increasing depth.
Sato, Haruo
JNC TN8400 99-064, 22 Pages, 1999/10
Four kinds of diffusion experiments; (1)through-diffusion(T-D) experiments for compaction direction dependency, (2)in-diffusion(I-D) experiments for composition dependency of silica sand in bentonite, (3)I-D experiments for initial bentonite gain size dependency, and (4)I-D experiments for the restoration property of an artificial single fracture in compacted bentonite, were carried out using tritiated water which is a non-sorbing nuclide to evaluate the effect of pore structural factors for eompacted bentonite on diffudion. For(1), effective diffusivities (De) in Na-bentonites, Kunigel-V1 and Kunipia-F were measured for 1.0 and 1.5 Mg
m
. For(2), apparent diffusivities (Da) in Kunigel-V1 were measured for 0.8, 1.4 and 1.8 Mgm with silica sand of 30 and 50 wt%. For(3), Da values for 0.8, 1.4 and 1.8 Mgm were measured for a granulated Na-bentonite, OT-9607 which grain-size distribution is in a rang between 0.1 and 5 mm. For (4), Da values in Kunigel-V1 which a single fracture was artificially reproduced and was immersed in distilled water for 7 or 28 days for the restoration of the fracture, were measured for 1.8 Mgm. Although De values in Kunigel-V1 were approximately the same for both compacted directions over the density, De values for perpendicular direction to compacted direction were higher than those for the same direction as compacted direction in Kunipia-F. For composition dependency of silica sand in bentonite, no significant effect of the mixure of silica sand in bentonite on Da was found. For initial bentonite grain size dependency, Da values obtained for OT-960 were approximately the same as those for Kunigel-V1 and no effect of initial grain size of bentonite on diffusion was found. For the restoration property of a single fracture in compacted bentonite, no restoration period dependency on Da was found. Based on this, it may be said that diffusion of nuclides in compacted bentonite, ...
Oda, Chie; Arthur, R. C,*; Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu; Neyama, Atsushi*
JNC TN8400 99-079, 287 Pages, 1999/09
Two thermodynamic databases for geochemical calculations supporting research and development on geological disposal concepts for high level radioactive waste are described in this report. One, SPRONS.JNC, is compatible with thermodynamic relations comprising the SUPCRT model and software, which permits calculation of the standard molal and partial molal thermodynamic properties of minerals, gases, aqueous species and reactions from 1 to 5000 bars and 0 to 1000
C. This database includes standard molal Gibbs free energies and enthalpies of formation, standard molal entropies and volumes, and Maier-Kelly heat capacity coefficients at the reference pressure (1 bar) and temperature (25C) for 195 minerals and 16 gases. It also includes standard partial molal Gibbs free energies and enthalpies of formation, standard partial molal entropies, and Helgeson, Kirkham and Flowers (HKF) equation-of-state coefficients at the reference pressure and temperature for 1147 inorganic and organic aqueous ions and complexes. SPRONS.JNC extends similar databases described elsewhere by incorporating new and revised data published in the peer-reviewed literature since 1991. The other database, PHREEQE.JNC, is compatible with the PHREEQE series of geochemical modeling codes. It includes equilibrium constants at 25C and 1 bar for mineral-dissolution, gas-solubility, aqueous-association and oxidation-reduction reactions. Reaction enthalpies, or coefficients in an empirical log K(T) function, are also included in this database, which permits calculation of equilibrium constants between 0 and 100C at 1 bar. All equilibrium constants, reaction enthalpies, and logK(T) coefficients in PHREEQE.JNC are calculated usig SUPCRT and SPRONS.JNC, which ensures that these two databases are mutually consistent. They are also internally consistent insofar as all the data are compatible with basic thermodynamic definitions and functional relations in the SUPCRT ...
Ota, Kunio; Nakano, Katsushi; Metcalfe, R.; Ikeda, Koki; ; Amano, Kenji; Takeuchi, Shinji; Hama, Katsuhiro; Matsui, Hiroya
JNC TN7410 99-007, 44 Pages, 1999/08
Sasamoto, Hiroshi; Yui, Mikazu; Arthur, R. C,*
JNC TN8400 99-033, 153 Pages, 1999/07
The results of hydrochemical investigations of groundwaters in the Kurihashi granodiorite at JNC's Kamaishi in-situ tests site indicate that these solutions are: (1)meteoric in origin, (2)chemically reducing (at depths greater than a few hundreds meters), (3)relatively young [residence times in the Kurihashi granodiorite generally less than about 40 years, but groundwaters older than several thousand years BP (before present) are also indicated by preliminary carbon-14 dating of samples obtained from the KH-1 borehole], (4)Ca-HCO
type solutions near the surface, changing to Na-HCO type groundwaters with increasing depth. The evolution of groundwater compositions in the Kurihashi granodiorite is modeled assuming local equilibrium for selected mineral-fluid reactions, taking into account the rainwater origin of these solutions. Results suggest it is possible to interpret approximately the "real" groundwater chemistry (i.e., pH, Eh, total dissolved concentrations of Si, Na, Ca, K, AI, carbonate and sulfate) in the Kurihashi granodiorite if the following assumptions are adopted: (1)CO
concentration in the gas phase contacting pore solutions in the overlying soil zone = 10
bar, (2)minerals in the rock zone that control the solubility of respective elements in the groundwater include; chalcedony (Si), albite (Na), kaolinite (Al), calcite (Ca and carbonate), microcline (K) and pyrite (Eh and sulfate). Discussions with international experts suggest a systematic approach utilizing reaction-path models of irreversible water-rock interactions in open systems may be needed to more realistically model groundwater evolution at the Kamaishi test site. Detailed information characterizing certain site properties (e.g., fracture mineralogy) may be required to adequately constrain such models, however.
Yui, Mikazu; Sasamoto, Hiroshi; Randolph C Arthu*
JNC TN8400 99-030, 201 Pages, 1999/07
According to the Japanese program for research and development of high level radioactive waste (HLW) disposal defined by Atomic Energy Commission (AEC), the second progress report (i.e., H-12 report) for performance assessment (PA) of HLW disposal is to be published by the Japan Nuclear Cycle Development Institute (JNC) and submitted to the Japanese government before the year 2,000 (AEC, 1997). This report presents the establishment of generic groundwater chemical compositions for the PA supporting the H-12 report. The following five hypothetical groundwaters are categorized for PA based on the results of the first progress report (i.e., H-3 report) and binaly statistical analyses of the screened groundwater dataset: (1)FRHP(Fresh-Reducing-High-pH) groundwater (2)FRLP(Fresh-Reducing-Low-pH) groundwater (3)SRHP(Saline-Reducing-High-pH) groundwater (4)SRLP(Saline-Reducing-Low-pH) groundwater (5)MRNP(Mixing-Reducing-Neutral-pH) groundwater. In order to define representative groundwater compositions for the PA for the H-12 report, JNC has established the representativeness of the above five hypothetical groundwaters by considering the results of multivariate statistical analyses, data reliability, evidence for geochemical controls on groundwater chemistry and exclusion criteria for potential repository sites in Japan. As a result, the following hypothetical reference groundwaters are selected for the performance assessment analysis in H-12 report, respectively: (1)Reference Case groundwater: FRHP groundwater, and (2)Alternative Geological Environment Case groundwater: SRHP groundwater. In addition, JNC has consulted with overseas experts on the concepts used in groundwater evolution modeling. This modeling effort has focussed on simulating equilibrium water-rock interactions to predict groundwater compositions resulting from reactions between initial water compositions and rock mineral assemblages. These discussions have centered on recommendations for developing ...
G M N BASTON*; J A BERRY*; M BROWNSWORD*; D J LLETT*; C M LINKLATER*; S W SWANTON*; Tweed, C. J.*
JNC TJ8400 99-078, 72 Pages, 1999/03
A desk study has been carried out to establish the feasibility of measuring the oxidation state of plutonium under near-neutral strongly-reducing conditions. X-ray absorbance spectroscopy appears to be capable of establishing the oxidation state of plutonium sorbed on a suitable substrate. An experimental and modelling investigation has been performed to study the sorption of plutonium onto basalt, mudstone and sandstone under strongly-reducing conditions at three concentrations of carbonate. Appropriate synthetic rock-equilibrated de-ionised water and seawater were used. A model has been developed to describe the sorption of plutonium onto basalt, mudstone and sandstone in de-ionised water and seawater. Predicted R
values are generally in good agreement with the observed experimental measurements. The model is based on sorption of plutonium(III) species and assumes iron oxide is the dominant sorbing phase.
*; *; *; *
JNC TJ1420 2000-003, 1020 Pages, 1999/03
JNC-TJ1420-2000-003.pdf:110.99MB
no abstracts in English
Okubo, Hiroo*
PNC TJ1222 94-002, 60 Pages, 1994/03
no abstracts in English
Yusa, Yasuhisa; ; Arai, Takashi
PNC TN8410 91-007, 18 Pages, 1990/12
This paper contains an overview of analogue studies for the assessment of long-term durability of engineered barrier materials at PNC Tokai. Materials of young age and with simple history are the most suitable for study as: (1)properties of the materials tend to deteriorate over longer historical time intervals; and (2) detailed quantitative data on time intervals and environmental conditions are more likely to be available. The following materials and their alteration phenomena were selected: (1)weathering alteration of basaltic glass (as vitrified waste form), (2)corrosion of iron in soil (as overpack), (3)illitization of smectite associated with contact metamorphism (as buffer material), (4)alteration of cement (as buffer or backfill material). (1)Weathering alteration of basaltic glass: Basaltic g1asses, from the Fuji and the Izu-Ohshima pyroclastic fall deposits were studied. The observations were made: (a)Climatological conditions have not varied significantly during the last three thousand years. Therefore, values for temperature, amount, and chemistry of ground water are quantified. (b)The cases studied could be regarded as leaching experiments in groundwater, using mass balances in water-g1ass interaction. (c)Although the groundwater is of Ca(Mg)-HCO type in the Fuji area and of Na-Cl type in the Izu-Ohshima, similar alteration ratios (2
3
m/1000yr) were obtained. (2)Corrosion of iron in soil: Industrial materials, such as gas/water service pipes of carbon steel or cast iron embedded in soil for 20 110 years, were selected for an analogue study of corrosion of iron in bentonite. The maximum corrosion rates obtained so far fall in the range of 0.040.09 mm/yr. (3)Illitization of smectite associated with contact metamorphism: In the Murakami bentonite deposit in central Japan, lateral variation of smectite to smectite/illite mixed-layer minerals are found in the aureole of the rhyolite intrusion body. Conversion of smectite to the