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Semba, Tsuyoshi; Osawa, Hideaki; ; Yabuuchi, Satoshi; Takeuchi, Shinji; Hama, Katsuhiro; Matsuoka, Toshiyuki
JNC TN7410 2002-007, 51 Pages, 2002/10
JNC-TN7410-2002-007.pdf:0.99MB
Tono Geoscience Center, Japan Nuclear Cycle Development Institute has been conducting a wide range of geoscientific research in order to build a firm scientific and technological basis for the research and development of geological disposal. One of the major components of the ongoing geoscientific research programme is the Regional Hydrogeological Study (RHS) project in the Tono region, central Japan. The main goal of the RHS project is to develop and demonstrate surface-based investigation methodologies to characterize geological environments on a regional scale in Japan. The RHS project was initiated in 1992. To date, remote sensing, geological mapping, airborne and ground geophysical investigations, and measurements in eleven deep boreholes have been carried out in the study area (c. 100 km
). Groundwater chemistry and hydraulic head monitoring is under way in these boreholes. Important results that have been obtained from these investigations include various information concerning the heterogeneity of lithological, hydrogeological and geochemical, and evolution of the groundwater geochemistry. During fiscal year 2001, hydraulic testing and groundwater sampling were conducted in borehole DH-13 which was drilled during fiscal year 2000. High density electrical resitivity measurements were conducted on a lineament. Groundwater monitoring was continued in the existing boreholes. As a part of evaluation of data uncertainties for modeling and simulation, study was started with the purpose of setting of modeling and simulation area around MIU constructionsite. Development of investigation instruments were also continued.
Takeuchi, Ryuji; Semba, Tsuyoshi; Nakano, Katsushi
Saikuru Kiko Giho, (8), p.49 - 56, 2000/09
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Semba, Tsuyoshi; Ogata, Nobuhisa;
PNC TN7410 92-044, 25 Pages, 1993/03
Power Reactor and Nuclear Fuel Development Corporation (PNC) has been developping techniques for evaluation of the spatial extent and dimension of fracture zones in rock mass. In a link of this purpose, PNC introduced the borehole radar system (RAMAC) which was developped in Stripa Project by OBCD/Nuclear Energy Agency. This report describes the results of singlehole measurements which were conducted in various rock masses in order to confirm the applicability of RAMAC system in Japan. The results are su㎜arized as follows; (1)For each borehole, we made radar reflection map, and interpreted reflectors from the map. (2)The propagation distance of electromagnetic waves through rock masses is determined by electric resistivity of rock masses. In the rock mass which resistivity is 100
m, propagation distance is less than 5m from a borehole with 20 MHz antenna. In the rock mass which resistivity is 10,000m, propagation distance is at least 100m from a borehole with the same antenna.
Semba, Tsuyoshi;
PNC TN7410 92-041, 23 Pages, 1992/10
Power Reactor and Nuclear Fuel Development Corporation (PNC) has been developping techniques for evaluation of grandwater flow in the granitic rock as crystalline rock. In the link of this purpose, PNC introduced the borehole radar system (RAMAC) because it is essential to investigate the spatial extent and dimensions of fracture zones. This report describes the results of tomographic analysis and reflection analysis which were made using crosshole data which were obtained at the Kamaishi In-situ Experiment Site. Reflection analysis is performed with reflection waves. With reflection analysis, it is possible to interpret the position and direction of a reflector because reflection waves reflect from some points on a reflector around the borehole. The results are su㎜arized as follows; (1)The location of reflectors exactly correspond to the boundary of between high and low velocity zones of electromagnetic waves. Furthermore, the direction of reflectors exactly correspond to the direction of fracture zones which were interpreted with tomographic analysis. (2)The reflectors are interpreted as boundary of moisture content in the rock because velocity of electromagnetic wave through the rock is influenced by moisture content in the rock. Therefore, reflection analysis reveals that the position and direction of boundary of between high and low moisture content zones is able to be interpreted. (3)When the distance between boreholes is narrow, in order to extract reflection waves from crosshole data clearly, it is necessary to shorten moving intervals of transmitter and receiver.
Semba, Tsuyoshi;
PNC TN7410 92-040, 25 Pages, 1992/10
Power Reactor and Nuclear Fuel Development Corporation (PNC) has been developping techniques for evaluation of the spatial extent and dimension of fracture zones in rock mass. In a link of this purpose, PNC introduced the borehole radar system (RAMAC) which was developped in Stripa Project by OBCD/Nuclear Bnergy Agency. This report describes the results of singlehole and crosshole measurements which were conducted in sedimentary rock in order to confirm applicablility of RAMAC in sedimentary rock. The results are summarized as follows; (1)The results of crosshole measurements. Bnough number of wave rays for tomographic analysis were obtained scarcely because resistivity of rock lass in which we had investigated was very low. Nevertheless, the relationship between electric resistivity which is obtained with electrical logging and propagation distance of electromagnetic waves are made clear, and electric resistivity reveals that it is possible to decide that radar method are applicable or not. (2)The results of singlehole measurements. Only three reflectors parallel to boreholes are obtained at deeper rock mass with comparativey high electric resistivity. These reflectors are interpreted as boreholes which were drilled around the measurement borehole.
Okita, Masatoshi*; Muneto, Masaru*; Hasegawa, Ken*; Nagasaki, Yasushi*; Koide, Kaoru*; Yamagishi, Akiko*; Semba, Tsuyoshi
JNC TN7400 2005-018, 241 Pages, 1992/04
JNC-TN7400-2005-018.PDF:10.21MB
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