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Onoe, Hironori; Kosaka, Hiroshi*; Matsuoka, Toshiyuki; Komatsu, Tetsuya; Takeuchi, Ryuji; Iwatsuki, Teruki; Yasue, Kenichi
Genshiryoku Bakkuendo Kenkyu (CD-ROM), 26(1), p.3 - 14, 2019/06
In this study, it is focused on topographic changes due to uplift and denudation, also climate perturbations, a method which is able to assess the long-term variability of groundwater flow conditions using the coefficient variation based on some steady-state groundwater flow simulation results was developed. Spatial distribution of long residence time area which is not much influenced due to long-term topographic change and recharge rate change during the past one million years was able to estimate through the case study of the Tono area, Central Japan. By applying this evaluation method, it is possible to identify the local area that has low variability of groundwater flow conditions due to topographic changes and climate perturbations from the regional area quantitatively and spatially.
Onoe, Hironori; Kosaka, Hiroshi*; Takeuchi, Ryuji; Saegusa, Hiromitsu
JAEA-Research 2015-008, 146 Pages, 2015/08
Mizunami Underground Research Laboratory (MIU) Project is being carried out by Japan Atomic Energy Agency (JAEA) in the Cretaceous Toki granite in the Tono area, central Japan. The MIU Project has three overlapping phases: Surface-based Investigation (Phase I), Construction (Phase II) and Operation (Phase III). In this study, calibration of hydrogeological model and groundwater flow simulation using the data obtained by the Phase I and Phase II were carried out in order to develop the methodology for construction and update of hydrogeological model on Site Scale. As a result, hydrogeological model on Site Scale, which is able to simulate comprehensively the obtained data regarding groundwater pressure distribution before excavation of the MIU facilities, hydraulic responses and inflow volume during excavation of the MIU facilities, was constructed.
Takeuchi, Ryuji; Kosaka, Hiroshi; Sato, Atsuya*; Tomiyama, Shingo*; Kageyama, Soichiro*; Ikeda, Makoto*
JAEA-Research 2011-008, 77 Pages, 2011/06
Subsurface water balance observation is a kind of methods in order to estimate a recharge rate. Results of the observation are affected by the various factors such as the scale, the topography, a geological feature, the climate. Therefore, the observation in the regional scale is necessary at many basins. The purpose of this study is to confirm the applicability of the method for the evaluation of runoff volume, which is one of parameters to evaluate the recharge rate by surface water balance observation, by geomorphometry and statistical analyses using digital elevation model (DEM). The runoff index which is the original indicator to evaluate the degree of flow rate on a catchment was calculated by the comparison between the result of geomorphometry and statistics analyses, and the observed data of river flow rate in the monitoring stations. Using this index, the flow rate of the Hiyoshi River was evaluated. The evaluated flow rate was about 60% against the observed flow rate.
Kosaka, Hiroshi; Saegusa, Hiromitsu; Onoe, Hironori; Takeuchi, Ryuji
JAEA-Research 2010-037, 42 Pages, 2011/01
Mizunami Underground Research Laboratory (MIU) Project is being carried out by Japan Atomic Energy Agency (JAEA) in the Cretaceous Toki granite in the Tono area, central Japan. The MIU project is a broad scientific study of the deep geological environment as a component of the research and development supporting geological disposal of high-level radioactive wastes. One of the main goals of the project is to establish techniques for comprehensive investigation, analysis and assessment of the deep geological environment in fractured crystalline rock. In this study, hydrogeological modeling and groundwater flow simulation taking into consideration the long-term pumping test has been carried out in order to reflect making test specifications of long-term pumping test. The pumping test will be carried out using the borehole, which will be drilled from underground research gallery in fiscal 2010. In this groundwater flow simulation, the sensitive analysis focused on location of pumping interval along the borehole, pumping time and pumping flow rate was conducted to predict the influence of these test specifications on the pressure response in pressure monitoring boreholes. As a result, the different variations of pressure response were indicated by the differences of the location of pumping interval bounded by the fault. In addition, small effect of difference of pumping time (2 weeks or 4 weeks) on pressure response was predicted. The recommendation of test specifications of long-term pumping test was made based on this study.
Takeuchi, Ryuji; Saegusa, Hiromitsu; Oyama, Takuya; Keya, Hiromichi; Sato, Atsuya; Kosaka, Hiroshi; Takeda, Masaki; Daimaru, Shuji; Takeuchi, Shinji
JAEA-Research 2010-018, 133 Pages, 2010/08
The Mizunami Underground Laboratory Project is a comprehensive research project investigating the deep underground environment within crystalline rock. The project goals of the project from surface-based investigation phase (Phase I) through to operation phase (Phase III) are: to establish techniques for investigation, analysis and assessment of the deep geological environment, and to develop a range of engineering for deep underground application. Currently, the project is under the construction phase (Phase II). One of the Phase II goals, which is for the project goal, was set to develop and revise models of the geological environment using the investigation results obtained during excavation, and determine and assess changes in the geological environment in response to excavation. This document presents the overview of results of the research and development on "hydrogeology" performed in fiscal year 2008, with regard to the Phase II goal.
Amaya, Masaki; Nakamura, Jinichi; Fuketa, Toyoshi; Kosaka, Yuji*
Journal of Nuclear Materials, 396(1), p.32 - 42, 2010/01
Times Cited Count:4 Percentile:29.61(Materials Science, Multidisciplinary)Two kinds of disk-shaped UO samples were irradiated in a test reactor up to about 60 and 130 GWd/t, respectively. The microstructures of the samples were investigated by means of optical microscopy, SEM/EPMA and micro-X-ray diffractometry. Thermal diffusivities of the irradiated samples were also measured and their thermal conductivities were evaluated. The thermal conductivity measurement results suggest that the amount of accumulated irradiation-induced defects depends on the irradiation condition of each sample. From the comparison of the changes in the lattice parameter and strain energy density before and after the thermal diffusivity measurements, it is likely that the thermal conductivity recovery in the temperature region from 1200 to 1500 K is related to the migration of dislocation.
Mizuno, Mineo*; Kosaka, Yuji*; Ogawa, Shinta*
JNC TJ8430 2005-002, 136 Pages, 2005/02
The measurement method of the thermal conductivity has been studied on the sintered UOparticles bed to investigate the necking effects on the thermal conductivity of the Vibro-packed fuel. In the years from 2002 to 2004, the experimental study was carried out in order to survey the sintering condition of UO
particles fuel bed, and it was certified that the effective thermal conductivity of the sintered UO2 particles bed could be measured by the apparatus which was constructed based on the Guarded-Comparative Longitudinal Heat Flow Technique. In this work, improvement of the apparatus in order to decrease heat loss from the sample in radial direction in the measurement of the thermal conductivity in high temperature region is carried out. Furthermore, the relation between necking ratio and the thermal conductivity of the sintered ZrO
spherical particles bed are surveyed to apply this apparatus to the thermal conductivity measurements of UO
spherical particle bed with high sphericity in next stage of study. The results indicate that necking ratio of particles can be controlled easily by the usage of spherical particles, and the relation between necking ratio and sintering strain can be applicable to low necking ratio region. The characteristics of the measurement apparatus are surveyed using quarts glass disc as a standard sample, and the error of the thermal conductivity measurements is estimated 3%(95% confidence limit) in 600~900deg. C , which is smaller than 8% estimated in the measurement of the thermal conductivity carried out in 2002. The thermal conductivity of the sintered ZrO
spherical particle bed depends on necking ratio of particles. This result is due to the homogeneity of necking in the particle bed by the usage of spherical particles and the improvement of accuracy of measured thermal conductivity using the advanced apparatus.
Mizuno, Mineo*; Kosaka, Yuji*; Mori, Yukihide*; Shimada, Takashi*
JNC TJ8410 2004-006, 85 Pages, 2004/03
/The process (the UPRISE method) of dissolving uranium and plutonium selectively and separating from oxide fuel using the amide system extraction solvent have been investigated. By the cold test which used Nd oxide so far, the dissolving of Nd with about 0.2 mol to the solvent of 250mL is confirmed. In this work, the investigations of the dissolving tendency of uranium to the amide system extraction solvent and decontamination factor (DF) of the typical fission product (FP) such as Nd were carried out, and following results are obtained. (1)In the test of the same dissolving conditions, the uranium dissolving rate to extraction solvent DOBA was approximately equivalent to the case of the DOiBA. (2)Three kinds of extraction solvent were examined in the same dissolving condition, the difference of the uranium dissolving rate was observed. The results of the dissolving rates indicated the order of NN'-hexyl-2, ethyl-hexan-amid-1.6 mol/L nitric acid complex NN'-dibutyl-butyl-amid-1.7 mol/L nitric acid complex
NN'-di-isobutyl-isobutyl-amid-1.5 mol/L nitric acid complex. (3)In the case of DOBA extraction solvent, the dissolving rate increased by about 2 order with the increase of the nitric acid concentration from 1mol/L up to 3.5mol/L and strong influence of the nitric acid concentration was confirmed to the dissolving rate. (4)In the tests with the NN'-dibutyl-butyl-amid-1.7 mol/L nitrie acid complex and NN'-di-isobutyl-isobutyl-amid-1.5 mol/L nitric acid complex, the DF values of Zr, Ru and Ce increased with the elapse of the test duration and exceeded 100 after 150 hours of test duration. On the other hand, the DF value indicated around 1 for Sr, Mo and Pd, and around 0.1 for Nd. (5)In the test with the NN'-hexyl-2-ehyl-hexan-amid-1.6 mol/L nitric acid complex, significant difference wasn't observed in the tendency of the elapsed change among the DF values of the FP elements. The DF values of all FP elements except Nd and Pd exceeded 100 after 100 ...
Mizuno, Mineo*; Kosaka, Yuji*; Ogawa, Shinta*
JNC TJ8430 2004-001, 93 Pages, 2004/02
Measurement of thermal conductivity of sintered UO2 particle bed was performed to investigate the necking effect on thermal conductivity. Test samples were prepared with high temperature creep test equipment. Plate comparison method was applied to the measurement. Thermal conductivity measurements were done for two neck ratio samples (0% and 37%) under the temperature from 600 to 800 Celsius degrees.
Mizuno, Mineo*; Kosaka, Yuji*; Ogawa, Shinta*
JNC TJ8430 2003-001, 73 Pages, 2003/02
no abstracts in English
Mori, Yukihide*; Shimada, Takashi*; Kosaka, Yuji*; Mizuno, Mineo*
JNC TJ8400 2003-013, 69 Pages, 2002/12
As a head end process for the pulverization of the spent fuel, the mechanical method (the shredder method) and the pyro-chemical method (oxidization heat-treatment) have been examined. UO is a main ingredient of Uranium oxide powder by the mechaical method, and U
O
is that by the pyro-chemical method. Moreover, the particle size of the pulverized powder depend on the conditions of the pulverizing process. As it was considered that the difference of dissolution rates of samples was caused by the difference of sample chemical forms and dissolution temperature, parametric surveys on chemical form and particle size of powder and dissolution temperature were carried out, and the following results were obtained. (1)The remarkable difference of dissolution rate between U
3O
powder(average particle size 3.7
m) and UO
powder (average particle size 2.4
m) which have comparatively similar particle size was not observed. (2)It was confirmed that the dissolution rate became lower according to the particle size increase (average particle size 2.4
m
1mm) And it was considered that dissolution rate had strong dependency on particle size, according to the results that the powder with 1mm particle size did not dissolute completely after 5 hours test. (3)The temperature dependency of the dissolution rate was confirmed by dissolution test with UO
powder (average particle size 2.4
m
1mm). The higher dissolution rate was obtained in the higher dissolution temperature, and 11 kcal/mol was obtained as activation energy of dissolution. (4)In the dissolution test of UO
powder, the nitric acid concentration started to change earlier than that of U
O
powder and concentration change range became larger compared with that in the dissolution test of U
O
powder. It was considered that those differences were caused by difference in mole ratio of Uranium and nitric acid which are consumed in the ...
Nakamura, Masahiro; Mizuno, Mineo*; Kosaka, Yuji*; Ogawa, Shinta*
JNC TJ8440 2002-003, 55 Pages, 2002/02
no abstracts in English
Okubo, Tadatsune*; Tsukuda, Yoshiaki*; Kamimura, Katsuichiro*; Murai, Kenji*; Goto, Ken*; Doi, Soichi*; Senda, Yasuhide*; Kosaka, Yuji*; Kido, Toshiya*; Murata, Tamotsu*; et al.
Nihon Genshiryoku Gakkai-Shi, 43(9), p.906 - 915, 2001/09
Times Cited Count:0 Percentile:0.00(Nuclear Science & Technology)no abstracts in English
Arai, Yasuo; Akabori, Mitsuo; Serizawa, Hiroyuki; Kosaka, Yuji*; Muta, Hiroaki*
no journal, ,
Outline of the results in FY2009 and summary for the three-years program of "Development of common and fundamental technologies on the evaluation of fuel behavior for realizing MA recycling", entrusted to JAEA by MEXT, are introduced.
Notaki, Tomohiro*; Kosaka, Yuji*; Takano, Masahide; Akabori, Mitsuo; Arai, Yasuo
no journal, ,
no abstracts in English
Onoe, Hironori; Takeuchi, Ryuji; Saegusa, Hiromitsu; Takeda, Masaki; Kosaka, Hiroshi; Daimaru, Shuji; Karino, Tomoyuki
no journal, ,
In this paper, a part of the result of long-term monitoring, hydrogeological modeling and groundwater flow simulation in Phase 2 of MIU project were introduced. And, methodology of model calibration based on the data of hydraulic impacts in Phase 2 was summarized.
Arai, Yasuo; Kosaka, Yuji*; Muta, Hiroaki*
no journal, ,
no abstracts in English
Sato, Fuminori; Nakanishi, Ryuji; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko
no journal, ,
no abstracts in English
Nakanishi, Ryuji; Sato, Fuminori; Kosaka, Ichiro; Nakano, Takafumi; Nagasato, Yoshihiko
no journal, ,
no abstracts in English
Kageyama, Soichiro*; Ikeda, Makoto*; Tomiyama, Shingo*; Takeuchi, Ryuji; Kosaka, Hiroshi
no journal, ,
no abstracts in English