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Hironaka, Kota; Ito, Fumiaki*; Lee, J.; Koizumi, Mitsuo; Takahashi, Tone; Suzuki, Satoshi*; Yogo, Akifumi*; Arikawa, Yasunobu*; Abe, Yuki*
Dai-42-Kai Nihon Kaku Busshitsu Kanri Gakkai Nenji Taikai Kaigi Rombunshu (Internet), 4 Pages, 2021/11
Neutron resonance transmission analysis (NRTA) is a method for non-destructive measurement of nuclear material by using a time-of-flight (TOF) technique with a pulsed neutron source. For NRTA system to carry out the short-distance TOF measurements with high resolutions, a short-pulsed neutron source is required. Laser-driven neutron sources (LDNSs) is very suitable as such a neutron source because of its short pulse width. Moreover, the compactness of the laser system is also expected due to the remarkable development of laser technology in recent years. In the present study, we have developed a technology for applying LDNS to the NRTA system and conducted the demonstration experiment using the LFEX laser at Osaka University to investigate the feasibility of the system. In this experiment, we successfully observed the neutron resonance peaks of indium and silver samples.
Ogawa, Yusuke*; Suzuki, Satoru*; Taniguchi, Naoki; Kawasaki, Manabu*; Suzuki, Hiroyuki*; Takahashi, Rieko*
Materials and Corrosion, 72(1-2), p.52 - 66, 2021/01
Times Cited Count:2 Percentile:12.73(Materials Science, Multidisciplinary)Cast steel is one of the promising alternative to forged steel that is the current reference material for carbon steel overpack. In this study, the full-scale cast steel overpack was produced experimentally and the distribution of casting defects were investigated. The corrosion test regarding corrosion rate and stress corrosion cracking (SCC) susceptibility were also conducted using samples taken from the full-scale cast steel overpack and the corrosion resistance of cast steel was compared with that of forged steel. From above two corrosion tests, it can be said that the corrosion resistance of cast steel is mostly the same as that of forged steel.
Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Kitamura, Akira; Yoshikawa, Hideki; Oda, Chie; Ishidera, Takamitsu; et al.
JAEA-Research 2014-030, 457 Pages, 2015/03
JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and post-closure performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, based on some examples of developing method of hydro-geological structure model, acquired knowledge are arranged using the tree diagram, and model uncertainty and its influence on the evaluation items were discussed. With regard to (2) study on scenario development, the developed approach for "defining conditions" has been reevaluated and improved from practical viewpoints. In addition, the uncertainty evaluation for the effect of use of cementitious material, as well as glass dissolution model, was conducted with analytical evaluation. With regard to (3) study on setting radionuclide migration parameters, based on survey of precedent procedures, multiple-approach for distribution coefficient of rocks was established, and the adequacy of the approach was confirmed though its application to sedimentary rock and granitic rock. Besides, an approach for solubility setting was developed including the procedure of selection of solubility limiting solid phase. The adequacy of the approach was confirmed though its application to key radionuclides.
Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Hayano, Akira; Makino, Hitoshi; Wakasugi, Keiichiro; Mitsui, Seiichiro; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.
JAEA-Research 2013-037, 455 Pages, 2013/12
Following FY2011, JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation stage. With regard to (1) study on rock suitability in terms of hydrology, the tree diagram of methodology of groundwater travel time has been extended for crystalline rock, in addition, tree diagram for sedimentary rock newly has been organized. With regard to (2) study on scenario development, the existing approach has been improved in terms of a practical task, and applied and tested for near field focusing on the buffer. In addition, the uncertainty of some important processes and its impact on safety functions are discussed though analysis. With regard to (3) study on setting radionuclide migration parameters, the approaches for parameter setting have been developed for sorption for rocks and solubility, and applied and tested through parameter setting exercises for key radionuclides.
Shibata, Masahiro; Sawada, Atsushi; Tachi, Yukio; Makino, Hitoshi; Hayano, Akira; Mitsui, Seiichiro; Taniguchi, Naoki; Oda, Chie; Kitamura, Akira; Osawa, Hideaki; et al.
JAEA-Research 2012-032, 298 Pages, 2012/09
JAEA and NUMO have conducted a collaborative research work which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation phase. The topics and the conducted research are follows; (1) Study on selection of host rock: in terms of hydraulic properties, items for assessing rock property, and assessment methodology of groundwater travel time has been organized with interaction from site investigation. (2) Study on development of scenario: the existing approach has been embodied, in addition, the phenomenological understanding regarding dissolution of and nuclide release from vitrified waste, corrosion of the overpack, long-term performance of the buffer are summarized. (3) Study on setting nuclide migration parameters: the approach for parameter setting has been improved for sorption and diffusion coefficient of buffer/rock, and applied and tested for parameter setting of key radionuclides. (4) Study on ensuring quality of knowledge: framework for ensuring quality of knowledge has been studied and examined aimed at the likely disposal facility condition.
Bolton, P.; Hori, Toshihiko; Kiriyama, Hiromitsu; Mori, Michiaki; Sakaki, Hironao; Sutherland, K.*; Suzuki, Masayuki; Wu, J.*; Yogo, Akifumi
Nuclear Instruments and Methods in Physics Research A, 620(1), p.71 - 75, 2010/08
Times Cited Count:12 Percentile:62.3(Instruments & Instrumentation)Yogo, Akifumi; Sato, Katsutoshi; Nishikino, Masaharu; Mori, Michiaki; Teshima, Teruki*; Numasaki, Hodaka*; Murakami, Masao*; Demizu, Yusuke*; Akagi, Takashi*; Nagayama, Shinichi*; et al.
Applied Physics Letters, 94(18), p.181502_1 - 181502_3, 2009/05
Times Cited Count:110 Percentile:94.75(Physics, Applied)Suzuki, Satoru; Kawamura, Katsuyuki*
Journal of Physical Chemistry B, 108, p.13468 - 13474, 2004/00
Times Cited Count:27 Percentile:57.53(Chemistry, Physical)None
Suzuki, Satoru; Tachi, Yukio; Sato, Haruo
Journal of Nuclear Science and Technology, 40(9), p.698 - 701, 2003/09
Times Cited Count:5 Percentile:36.81(Nuclear Science & Technology)None
Suzuki, Satoru
JNC TN8400 2002-006, 310 Pages, 2002/05
Bentonite is a promising candidate of buffer material for geological disposal of high-level radioactive waste (HLW). Mass transport in bentonite is mainly controlled by diffusion process because of extremely low-permeability. Geological environments, e.g. salinity of ground water and temperature can strongly influence on migration behavior in bentonite, and therefore diffusivity and diffusion mechanism have been investigated experimentally and theoretically. In chapter 1, the author summarizes how the diffusivity in the buffer material has been treated in the safety assessment. In chapter 2, results of diffusion experiments as a function of salinity and temperature have been shown. In chapter 3, relationship between diffusivity and pore structure of bentonite has been investigated theoretically. In chapter 4, sorption structure of strontium on smectite has been studied by using molecular dynamics simulation. In chapter 5, vibrational property of pore water has been investigated Diffusivity in bentonite has been discussed based on rock capacity factor, microstructure and interaction between diffusant and bentonite.
Suzuki, Satoru; Sato, Haruo
JNC TN8400 2002-002, 46 Pages, 2002/05
For a better understanding of the relationship between groundwater salinity and diffusivity of radionuclides in compacted bentonite, salinity dependences of effective diffusion coefficients De for I, Sr and HDO were investigated using a through-diffusion method. A sodium-bentonite was purified from Kunipia F (Na-montmorillonite content 99 wt.%), in order to eliminate unknown influences of impurities (e.g. quartz and organic substances), MX80 bentonite also used included 25% of impurities. The powdered sample was compacted to a dry bulk density () of 0.9 Mg/m or 1.6 Mg/m for the purified bentonite and 1.8 Mg/m for MX80 bentonite. These samples were then soaked in NaCl solutions of 0.01 to 0.5 M. Effective diffusion coefficients for I and Sr and increased with increasing salinity as represented by the power law, while De for HDO was almost constant. A salinity dependence of De in compacted sodium-bentonite was well expressed by the power n that was practically independent of impurities or dry densities. The Power n was evaluated to be 0.5 to 0.7 for anions (I and Cl), about 1.5 for Sr and 0.0 to 0.1 for HDO. Deuterated water may migrate through both interstitial pore water and interlamellar water, whereas iodine (I) may prefer interstitial pore water as major diffusion pathways as interpreted by the anion exclusion effect. On the other hand, a positive salinity dependence of De for Sr conflicts with the previously reported tendency explained by the surface diffusion theory. Discrepancies can be considered to be due to the diffusion cell design on the basis of rock capacity factor and boundary conditions for Sr.
Suzuki, Satoru; Sato, Haruo; Ishidera, Takamitsu; Fujii, Naoki*; Kawamura, Katsuyuki*
JNC TN8400 2001-031, 44 Pages, 2002/05
In order to quantify effect of temperature on diffusivity of deuterated water (HDO) in compacted sodium-bentonite, through-diffusion experiments were conducted at elevated tempemture from 298 to 333 K. Kunipia F (Na-montmorillonite content 98 wt. %; Kunimine Industly Co.) was compacted to a dry density of 0.9 and l.35 Mg/m. Since smectite flakes were perpendicularly oriented to a direction of compaction, anisotropy of diffusivity was investigated parallel and normal to the preferred orientation of smectite. Effective diffusion coeficient D of HDO was larger for a diffusional direction parallel to the preferred orientation than normal to that for both dry densities. These results well agreed to the previously reported ones for tritiated water. Activation energies of D in compacted bentonite increased with increasing dry density in the range of 19 - 25 kJ/mol which was slightly larger than that in bulk water (18 kJ/mol). This relationship can be considered to be due to both the pore structure development and high activation energy of water (18-23 kJ/mol) in the vicinity of smectite surface (within 2 nm) on the basis of molecular dynamics simulations.
Kawamura, Katsuyuki*; Ichikawa, Yasuaki*; Suzuki, Satoru; Shibata, Masahiro; Sato, Haruo; Ueno, Kenichi
JNC TY8400 2002-015, 90 Pages, 2002/03
None
Suzuki, Satoru; Sato, Haruo
JNC TN8410 2001-028, 36 Pages, 2002/03
For a safety assessment of the high-level radioactive waste disposal, effective diffusion coefficients (D) of radionuclides in bentonite have been accumulated by the through-diffusion method. It has been found recently that experimental results on Ds for several cations (cesium and strontium) by the fairly standard experimental method in JNC differ from those previously reported in several papers. Discrepancy can be considered to be due to different design of diffusion cell and system. In order to confirm influences of the experimental design on cation diffusivities in bentonite, a flow-through diffusion system was developed and several diffusion experiments were conducted.As a result, magnitude of D and its salinity dependence were relatively different between the standard and flow-through diffusion system. Since the latter system can control boundary conditions of the experiment more strictly than the standard method, we can conclude that the flow-through diffusion system provide correct results. In addition, we apply this flow-through diffusion system to a modification of controlling boundary condition during the experiment and to the diffusion experiment under controlled temperature.
Suzuki, Satoru
2001 MRS Fall Meeting, 0 Pages, 2002/00
None
Sato, Haruo; Suzuki, Satoru
Special Workshop of Clay Microstructure and its Importance Soil Behaviour, p.87 - 96, 2002/00
None
Suzuki, Satoru; Fujishima, Atsushi; Ueno, Kenichi; Ichikawa, Yasuaki*; Kawamura, Katsuyuki*; Fujii, Naoki*; Shibata, Masahiro; Sato, Haruo; Kitayama, Kazumi*
Nendo Kagaku, 41(2), p.43 - 57, 2001/12
None
Suzuki, Satoru
Saikuru Kiko Giho, (13), p.65 - 75, 2001/12
None
Suzuki, Satoru; Fujishima, Atsushi; Ueno, Kenichi; Ichikawa, Yasuaki*; Kawamura, Katsuyuki*; Fujii, Naoki*; Shibata, Masahiro; Sato, Haruo
JNC TY8400 2001-003, 66 Pages, 2001/05
no abstracts in English