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Journal Articles

Development of evaluation method for variability of groundwater flow conditions associated with long-term topographic change and climate perturbations

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.

JAEA Reports

Study of hydrogeology in the Mizunami Underground Research Laboratory Project; Hydrogeological modeling at site scale in Phase II

Onoe, Hironori; Kosaka, Hiroshi*; Takeuchi, Ryuji; Saegusa, Hiromitsu

JAEA-Research 2015-008, 146 Pages, 2015/08

JAEA-Research-2015-008.pdf:76.46MB

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.

JAEA Reports

Estimation of runoff volume by geomorphometry and statistics analysis using digital elevation model in Tono area

Takeuchi, Ryuji; Kosaka, Hiroshi; Sato, Atsuya*; Tomiyama, Shingo*; Kageyama, Soichiro*; Ikeda, Makoto*

JAEA-Research 2011-008, 77 Pages, 2011/06

JAEA-Research-2011-008.pdf:4.76MB

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.

JAEA Reports

Study on hydrogeology on the Mizunami Underground Research Laboratory Project; Hydrogeological modeling and groundwater flow simulation for planning of long-term pumping test

Kosaka, Hiroshi; Saegusa, Hiromitsu; Onoe, Hironori; Takeuchi, Ryuji

JAEA-Research 2010-037, 42 Pages, 2011/01

JAEA-Research-2010-037.pdf:16.27MB

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.

JAEA Reports

Study on hydrogeology on the Mizunami Underground Research Laboratory Project annual report for fiscal year 2008

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

JAEA-Research-2010-018.pdf:28.5MB

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.

Journal Articles

Relationship between changes in the crystal lattice strain and thermal conductivity of high burnup UO$$_2$$ pellets

Amaya, Masaki; Nakamura, Jinichi; Fuketa, Toyoshi; Kosaka, Yuji*

Journal of Nuclear Materials, 396(1), p.32 - 42, 2010/01

 Times Cited Count:4 Percentile:30.68(Materials Science, Multidisciplinary)

Two kinds of disk-shaped UO$$_2$$ 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.

JAEA Reports

Thermal Conductivity Measurement of Sintered Vibro-Packed Fuel (4)

Mizuno, Mineo*; Kosaka, Yuji*; Ogawa, Shinta*

JNC TJ8430 2005-002, 136 Pages, 2005/02

JNC-TJ8430-2005-002.pdf:30.86MB

The measurement method of the thermal conductivity has been studied on the sintered UO$$_{2}$$particles 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$$_{2}$$ 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$$_{2}$$ spherical particles bed are surveyed to apply this apparatus to the thermal conductivity measurements of UO$$_{2}$$ 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$$_{2}$$ 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.

JAEA Reports

The Dissolving Test of the Uranium Oxide using Amide System Extraction Solvent

Mizuno, Mineo*; Kosaka, Yuji*; Mori, Yukihide*; Shimada, Takashi*

JNC TJ8410 2004-006, 85 Pages, 2004/03

JNC-TJ8410-2004-006.pdf:3.05MB

/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 ...

JAEA Reports

Thermal Conductivity Measurement of Sintered Vibro-Packed Fuel (3) -Thermal Conductivity Measurement-

Mizuno, Mineo*; Kosaka, Yuji*; Ogawa, Shinta*

JNC TJ8430 2004-001, 93 Pages, 2004/02

JNC-TJ8430-2004-001.pdf:7.42MB

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.

JAEA Reports

Thermal conductivity measurement of sintered Vibro-packed fuel, 2; Study on thermal conductivity measurement method

Mizuno, Mineo*; Kosaka, Yuji*; Ogawa, Shinta*

JNC TJ8430 2003-001, 73 Pages, 2003/02

JNC-TJ8430-2003-001.pdf:5.66MB

no abstracts in English

JAEA Reports

Dissolution of uranium oxide TBP-HNO$$_{3}$$ complex

Mori, Yukihide*; Shimada, Takashi*; Kosaka, Yuji*; Mizuno, Mineo*

JNC TJ8400 2003-013, 69 Pages, 2002/12

JNC-TJ8400-2003-013.pdf:3.53MB

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$$_{2}$$ is a main ingredient of Uranium oxide powder by the mechaical method, and U$$_{3}$$O$$_{8}$$ 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$$_{3}$$3O$$_{8}$$ powder(average particle size 3.7$$mu$$m) and UO$$_{2}$$ powder (average particle size 2.4$$mu$$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$$mu$$m$$sim$$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$$_{2}$$ powder (average particle size 2.4$$mu$$m $$sim$$ 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$$_{2}$$ powder, the nitric acid concentration started to change earlier than that of U$$_{3}$$O$$_{8}$$ powder and concentration change range became larger compared with that in the dissolution test of U$$_{3}$$O$$_{8}$$ powder. It was considered that those differences were caused by difference in mole ratio of Uranium and nitric acid which are consumed in the ...

JAEA Reports

Thermal conductivity measurement of sintered Vibro-packed fuel, 1; Study on sample preparation method

Nakamura, Masahiro; Mizuno, Mineo*; Kosaka, Yuji*; Ogawa, Shinta*

JNC TJ8440 2002-003, 55 Pages, 2002/02

JNC-TJ8440-2002-003.pdf:13.04MB

no abstracts in English

Journal Articles

Irradiation test for verification of PWR 48GWd/t high burnup fuel

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:0.01(Nuclear Science & Technology)

no abstracts in English

Oral presentation

Development of vibro-packed fuel design code, 13; Necking ratio measurement of the spherical particle bed

Nakamura, Masahiro; Kase, Takeshi; Koizumi, Tsutomu; Mizuno, Mineo*; Kosaka, Yuji*; Ogawa, Shinta*; Sekine, Nobuyuki*

no journal, , 

Particles in the sphere-pac fuel will sinter together due to high temperature and high pressure during an irradiation. Interparticle sintering will improve the effective thermal conductivity of the particle bed. Necking ratio is introduced to take the development of it to a fuel design code. Accuracy of the necking ratio measurement with the ceramography in a post irradiation examination was evaluated by the comparison of the results of ceramography measurement and fracture surface measurement.

Oral presentation

Oral presentation

Development of common and fundamental technologies on nuclear fuel behavior for realizing MA recycling, 1; Outline

Arai, Yasuo; Akabori, Mitsuo; Serizawa, Hiroyuki; Kosaka, Yuji*; Uno, Masayoshi*

no journal, , 

no abstracts in English

Oral presentation

Hydrogeological study of the Mizunami Underground Research Laboratory project

Keya, Hiromichi; Takeuchi, Ryuji; Toya, Naruhisa; Sato, Atsuya; Saegusa, Hiromitsu; Oyama, Takuya; Kosaka, Hiroshi

no journal, , 

no abstracts in English

Oral presentation

Maintenance of estimate technique for paleo-topography and paleo-climate for the past several hundred thousand years based on data from research and field investigations

Onoe, Hironori*; Shiomi, Tetsuya*; Tokusu, Mitsuhiro*; Hirakawa, Yoshiaki*; Kusano, Tomohiro; Yasue, Kenichi; Kosaka, Hiroshi; Saegusa, Hiromitsu; Takeuchi, Ryuji; Nohara, Tsuyoshi; et al.

no journal, , 

no abstracts in English

Oral presentation

Development of common and fundamental technologies on the eveluation of fuel behavior for realizing MA recycling, 6; Outline of the results obtained in FY2008

Arai, Yasuo; Akabori, Mitsuo; Serizawa, Hiroyuki; Kosaka, Yuji*; Uno, Masayoshi*; Muta, Hiroaki*

no journal, , 

It is indispensable for realizing recycling minor actinides (MA) to understand and control the peculiar behavior of MA-bearing fuels, which could not be extrapolated from the present LWR fuel cycle technologies. In particular, the behavior of He produced in the irradiation and strage periods of MA-bearing fuels, and the effect of addition of Am and Cm on the fuel properties of oxide fuel have not been satisfactorily clarified so far. From these viewpoints, a three-years R&D program "Development of common and fundamental technologies on the evaluation of fuel behavior for realizing MA recycling" was started in JFY2007 under the "Innovative Nuclear Research and Development Program" entrusted by MEXT. The outline of the results obtained in JFY2008 is introduced in the presentation.

Oral presentation

32 (Records 1-20 displayed on this page)