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*; *;
JNC TN8430 2001-003, 64 Pages, 2001/03
JNC-TN8430-2001-003.pdf:10.04MB
Handling methods and test conditions of hydraulic tests for NETBLOCK system had been examined by using acrylic and/or artificial rock specimen. A natural rock specimen (granite : excavated from Kamaishi mine) with fracture intersection was formed into practicable size for NETBLOCK system. Recently, we conducted a series of hydraulic test, in order to study the influence of fracture intersection by using the natural rock specimen. Hydraulic tests were conducted under several centimeters of head, which could be controlled by improved system because hydraulic permeability of target fractures were high. As a result, 10
10
(m
/s) orders of hydraulic transmissivity of target fractures could be measured. A low permeability in the NW direction at the lower fracture was estimated from the heterogeneous head distribution. However, it is also expected that turbulence flow might be occurred under this study condition because fracture permeability is high and flow rate through the fracture is relatively high. In case of turbulence-flow, an estimated hydraulic transmissivity is low. High-viscosity fluid hydraulic test to achieve laminar flow will be needed for correcting an evaluated transmissivity.
Chijimatsu, Masakazu*; Fujita, Tomoo; Sugita, Yutaka; Taniguchi, Wataru
JNC TN8400 2000-008, 339 Pages, 2000/01
JNC-TN8400-2000-008.pdf:30.96MB
Geological disposal of high-level radioactive waste (HLW) in Japan is based on a multibarrier system composed of engineered and natural barriers. The engineered barriers are composed of vitrified waste confined within a canister, overpack and buffer material. Highly compacted bentonite clay is considered one of the most promising candidate buffer material mainly because of its low hydraulic conductivity and high adsorption capacity of radionuclides. In a repository for HLW, complex thermal, hydraulic and mechanical (T-H-M) phenomena will take place, involving the interactive processes between radioactive decay heat from the vitrified waste, infiltration of ground water and stress generation due to the earth pressure, the thermal loading and the swelling pressure of the buffer material. In order to evaluate the performance of the buffer material, the coupled T-H-M behaviors within the compacted bentonite have to be modelled. Before establishing a fully coupled T-H-M model, the mechanism of each single Phenomenon or partially coupled phenomena should be identified. Furthermore, in order to evaluate the coupled T-H-M phenomena, the analysis model was developed physically and numerically and the adequacy and the applicability was tested though the engineered scale laboratory test and in-situ test. In this report, the investigative results for the development of coupled T-H-M model were described. This report consists of eight chapters. In Chapter l, the necessity of coupled T-H-M model in the geological disposal project of the high-level radioactive waste was described. In Chapter 2, the laboratory test results of the rock sample and the buffer material for the coupled T-H-M analysis were shown. The rock samples were obtained from the in-situ experimental site at Kamaishi mine. As the buffer material, bentonite clay (Kunigel V1 and Kunigel OT-9607) and bentonite-sand mixture were used. In Chapter 3, in-situ tests to obtain the rock property were shown. As ...
; ; Kameyama, Iwao; ; ; *; *
JAERI-Tech 99-075, p.87 - 0, 1999/10
no abstracts in English
; ; Koide, Kaoru; Yanagizawa, Koichi
PNC TN7410 95-012, 65 Pages, 1995/05
An extensive study program has been carried out by PNC to estimate hydrogeological characteristics of deep underground in Japan. As a part of this program, groundwater flow analyses in Hokkaido were conducted. For the analyses of Hokkaido area (500 km 
400 km 10 km deep), a hydrogeological model representing topography, distribution of hydraulic conductivity was developed on the strength of information available from open literature. By the use of this model, steady state three-dimensional groundwater flow under a saturated-unsaturated condition was calculated by means of finite element method. The results are as follows : (1)Distribution of piezometric head corresponds with topography in the study area. (2)Piezometric head distribution is hydrostatic below E.L.-1000 m in the study area. (3)Hydraulic gradient in the study area is less than 0.04 below E.L. -500 m. (4)Difference of boundary conditions at the shore side this model does not affect the result of the analyses.
Sakaki, Toshihiro
PNC TN7410 95-002, 45 Pages, 1995/04
It is considered that boreholes drilled from a drift cause disturbance to the surrounding hydraulic environment. In the study on the excavation disturbance, it is necessary to understand the influence of boreholes for proper evaluation of aquired data. Using the two-dimensional F.E.M. analysis, an influence of a borehole on the surrounding hydraulic environment and an effect of sealing packers are investigated preliminarily. The results are as follows. (1)Allowing groundwater to leak out from a borehole, pressure head in the vicinity decreased. (2)Placing sealing packers, the decrease in pressure head was reduced. (3)The more packers, the more effective. This report describes the detailed results and discussions of the investigation.
Yanagizawa, Koichi; Imai, Hisashi; ; Wakamatsu, Hisanori; Umeda, Koji
PNC TN7410 92-019, 68 Pages, 1992/07
Groundwater flow was analysed in the two areas of different scale situated in central Japan, in order to estimate hydrological condition existing at the deep underground in Japan. For the analysis in the Central Japan area (300 500km 10km deep), a hydrogeological model (a model expressing distribution of hydraulic conductivity) was built up with data from literature published so far. The model in the Tono area (8 7km 3km deep) which is a part of the Central Japan area, a hydrogeological model was built up with field data from the area studied. Based on these models, steady state three-dimensional groundwater flow under a saturated-unsaturated condition was calculated by means of FEM. The results are as follows: (1)In the Central Japan area, distribution of piezometric head harmonizes with topography in the area. (2)In the Tono area, distribution of piezometric head in the sub-surface part is governed by local topography, while that in the deeper part is governed by underlying regional topography. (3)In both areas, vertical variation of piezometric head is rather small without the shallow part, which indicates hydrostatic distribution. (4)Hydraulic gradient is less than 0.04 in the most part below GL-500m in both areas. (5)The results of the analysis in the Central Japan area show that types of distribution of hydraulic conductivity below EL-3,000m, of relationship between saturation ratio and pressure head, and of lateral boundary condition, do not remarkably affect the flow situation.
Sudo, Yukio
Journal of Nuclear Science and Technology, 17(1), p.1 - 15, 1980/00
Times Cited Count：15 Percentile：80.15(Nuclear Science & Technology)no abstracts in English
