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Goto, Takahiro*; Mitsui, Seiichiro; Takase, Hiroyasu*; Kurosawa, Susumu*; Inagaki, Manabu*; Shibata, Masahiro; Ishiguro, Katsuhiko*
MRS Advances (Internet), 1(63-64), p.4239 - 4245, 2016/00
NUMO and JAEA have conducted a joint research since FY2011, which is designed to enhance the methodology of repository design and performance assessment in preliminary investigation stage for deep geological disposal of radioactive waste. As a part of this joint research, we have been developing glass dissolution models which consider various processes in EBS, such as precipitation of Fe-silicates associated with iron overpack corrosion, and Si transport through corrosion products in the cracked overpack. The objectives of the modeling work are to evaluate relative importance of relevant processes and to identify further R&D issues towards development of a convincing safety case. Sensitivity analyses suggested that predicted glass dissolution time ranges from 1
10
to 110
years or more due to uncertainties in the current understanding of the key processes, namely precipitation of Fe-silicates and transport characteristics of the altered glass layer.
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-Research-2014-030.pdf:199.23MB
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
JAEA-Research-2013-037.pdf:42.0MB
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-Research-2012-032.pdf:33.68MB
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.
Ebisawa, Hiroyuki; Hanakawa, Hiroki; Asano, Norikazu; Kusunoki, Hidehiko; Yanai, Tomohiro; Sato, Shinichi; Miyauchi, Masaru; Oto, Tsutomu; Kimura, Tadashi; Kawamata, Takanori; et al.
JAEA-Technology 2009-030, 165 Pages, 2009/07
JAEA-Technology-2009-030.pdf:69.18MB
The condition of facilities and machinery used continuously were investigated before the renewal work of JMTR on FY 2007. The subjects of investigation were reactor building, primary cooling system tanks, secondary cooling system piping and tower, emergency generator and so on. As the result, it was confirmed that some facilities and machinery were necessary to repair and others were used continuously for long term by maintaining on the long-term maintenance plan. JMTR is planed to renew by the result of this investigation.
Kawamura, Makoto; Oi, Takao; Niizato, Tadafumi; Yasue, Kenichi; Tokiwa, Tetsuya; Niwa, Masakazu; Shimada, Koji; Kurosawa, Hideki; Asamori, Koichi; Kawachi, Susumu; et al.
JAEA-Research 2008-018, 47 Pages, 2008/03
JAEA-Research-2008-018.pdf:24.18MB
In this report, we sophisticated the framework as a part of the total system performance assessment for two purposes: the first one is quantification of relationship of characteristic of natural phenomena between geological environmental conditions (THMCG), and the other one is quantification of relationship of THMCG condition between parameters of performance assessment. On the other hand, we applied the sophisticated framework to all natural phenomena. As a result, to apply the sophisticated framework, we could show that information integration could carry out efficiently. Moreover, we have checked that the framework was applicable to all phenomena. Furthermore, we could show that suitable scenarios might be chosen by information integration.
Kurosawa, Susumu; Nagasaki, Shinya*; Tanaka, Satoru*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 6(2), p.205 - 213, 2007/06
no abstracts in English
Kurosawa, Susumu; Mizukami, Masashi*; Sato, Hisao*; Nozawa, Jun*; Tsujimoto, Keiichi*; Kurihara, Kazue*
Nihon Genshiryoku Gakkai Wabun Rombunshi, 5(3), p.251 - 256, 2006/09
no abstracts in English
Kurosawa, Susumi; Tanaka, Satoru*; James, S. C.*; Yui, Mikazu
Journal of Nuclear Science and Technology, 43(5), p.605 - 609, 2006/05
Times Cited Count：8 Percentile：49.58(Nuclear Science & Technology)In this work, the effective clay density as a function of interstitial pore size was estimated by applying the homogenization analysis (HA) of bentonite. In the estimation by the HA method, the interstitial pore size was set up to be 
1 nm which is the smallest size equivalent to colloid. The results indicate that the interstitial pore is estimated to be 1 nm or less if the effective clay density in the buffer is higher than 1.5 Mg/m
and it is also suggested that the penetration of colloidal fine particles in the buffer did not occur.
Sasamoto, Hiroshi; Kurosawa, Susumu; Isogai, Takeshi*; Yoshikawa, Hideki
Hoshasei Haikibutsu Anzen Kenkyu Nenji Keikaku (Heisei-13-Nendo
Heisei-17-Nendo) Kenkyu Seika Hokokushu, p.146 - 152, 2006/03
no abstracts in English
Yoshikawa, Hideki; Shibata, Masahiro; Sasamoto, Hiroshi; Iijima, Kazuki; Sato, Haruo; Kitamura, Akira; Ishidera, Takamitsu; Fujiwara, Kenso; Kurosawa, Susumu; Xia, X.; et al.
Hoshasei Haikibutsu Anzen Kenkyu Nenji Keikaku (Heisei-13-NendoHeisei-17-Nendo) Kenkyu Seika Hokokushu, p.153 - 170, 2006/03
no abstracts in English
Kurosawa, Susumi
JNC TN8400 2005-007, 36 Pages, 2005/03
JNC-TN8400-2005-007.pdf:1.73MB
This paper presents the examinations that were performed after publication of the H12 report to evaluate the effects of colloids in the engineered barrier, the natural barrier and these boundaries on the performance assessment of radioactive waste geological disposal system. This paper presents the interesting topics that is summarized as a dissertation based on results (contributed papers) obtained in Japan Nuclear Cycle Development Institute by studying under with Prof. Satoru Tanaka, Department of Quantum Engineering and Systems Science, The School of Engineering, The University of Tokyo.
Kurosawa, Susumi; Yui, Mikazu; Yoshikawa, Hideki
International Symposium NUCEF2005, 0 Pages, 2005/02
It is reported that the nuclide migration in groundwater is enhanced according to transport behavior of colloids compared with the migration behavior as the ion when the nuclide generates colloids. For example, in the colloids and radionuclide retardation experiment (CRR experiment) in the Grimusel test site in Switzerland had been performed as collaboration of JNC and NAGRA (Switzerland), the possibility that the nuclide migration was enhanced by the influence of the colloids in the groundwater was indicated. We will present on the simulations of the analysis by numerical code COLFRAC which describes colloid-facilitated solute transport in fractured media. Moreover, in order to evaluate the impact of microorganism on the performance assessment for geological disposal of HLW, we simulated effects of microorganism on radionuclide migration by using the COLFRAC code.
Kurosawa, Susumi; Yui, Mikazu; Yoshikawa, Hideki
International Symposium NUCEF2005, 0 Pages, 2005/02
On the geological disposal of high-level radioactive waste (HLW), it is known that the actinide ion which is released from the HLW generates true-colloids with hydrolysis reaction, and forms pseudo- colloids by sorption reaction onto the colloids in the groundwater. Recently, it is reported that the radionuclide migration in groundwater is enhanced by transport behavior of colloids compared with the migration behavior of the solute. For example, the in-situ experiment on the colloids and radionuclide retardation (CRR experiment) in the Grimsel test site in Switzerland had been performed by the collaboration among NAGRA (Switzerland), ENRESA (Spain), ANDRA (France), FZK-INE (Germany), USDoE/SNL (U.S.A) and JNC (Japan), the possibility of the radionuclide migration enhancement by the influence of the colloids was indicated. We will present the modeling results by numerical code COLFRAC which describes colloid-facilitated solute transport in fractured media. Moreover, in order to evaluate the impact of microorganisms on the performance assessment for geological disposal of HLW, we simulated effects of microorganism as a colloid on radionuclide migration by using the COLFRAC code.
Yui, Mikazu; Kurosawa, Susumi; Iijima, Kazuki
Genshiryoku Bakkuendo Kenkyu, 11(1), p.45 - 51, 2005/00
The information of experimental and theoretical studies which were performed with Japan Nuclear Cycle Development Institute (JNC) as leader to evaluate the influence of colloid, organic material and microorganism in artificial barrier, natural barrier and its boundary area on performance assessment of radioactive waste geological disposal system were presented. Furthermore, the experimental and analytical results of laboratory and in-situ programs which were performed on and after compilation of the results of R&D studies relevant to radioactive waste management by JNC to develop and advance the transport model of radionuclide with colloid, organic material and microorganism were indicated.
Kurosawa, Susumi; Ibaraki, Motomu*; Scott, J.*; Yui, Mikazu; Russell, A.*
JNC TN8400 2004-016, 35 Pages, 2004/09
JNC-TN8400-2004-016.pdf:1.18MB
To evaluate the influence of colloids on radionuclide transport through the fractured rock, the colloid and radionuclide retardation experiment project were carried out in a shear zone in the Grimsel Test Site on one of JNC-NAGRA internatinal collaboration programs. In this study, the results of the transport experiments were analyzed by numerical simulation code of radionuclide transport, COLFRAC, which describe colloid-facilitated solute transport in fractured media.
Kurosawa, Susumi; Ibaraki, Motomu*; Yui, Mikazu; Ueta, Shinzo*; Yoshikawa, Hideki
Nihon Genshiryoku Gakkai Wabun Rombunshi, 3(3), p.249 - 256, 2004/09
Colloidal effect is one of the major factors to enhance the transport of radionuclide in groundwater. In this study, the impact of kinetic reactions of radionuclide sorption onto both the fracture wall and colloid on the transport behavior of radionuclide were investigated by carrying out the transport experiment of the radionuclide with colloid through fractured rock. In the experiments, the Cs and clay colloid were used as moderately sorbing radionuclide and typical natural colloid by the concentration of 1.010
g/l (7.510
mol/l) and 3.510
g/l, respectively. The granodiorite with artificially the single fracture (dimension: 50500.5 mm) was used. The results of the transport experiments were analyzed by numerical simulation code of radionuclide transport COLFRAC which can model radionuclide transport based on either equilibrium or kinetic reaction of radionuclide sorption onto fracture wall and colloid. Consequently, it was indicated that calculated results strongly dep
Kurosawa, Susumi; Sasaki, Ryoichi; Ueta, Shinzo*; Yoshikawa, Hideki
JNC TN8400 2004-012, 68 Pages, 2004/07
JNC-TN8400-2004-012.pdf:5.37MB
In order to evaluate the impact of microorganism by COLFRAC, which simulates colloid-facilitated contaminant migration, the microorganism - radionuclide sorption data and microbial films data in deep geological environment were surveyed. After the survey, the data conversion to be able to calculate the effect of them on performance assessment in COLFRAC has been undertaken. As the results of calculation by COLFRAC, the transport behavior of radionuclide may be enhanced, when radionuclide will be taken in the microorganism. Furthermore, the results indicated that the transport rate of radionuclide depends on microbial concentration.
Kurosawa, Susumi; Yui, Mikazu; Yoshikawa, Hideki; Ibaraki, Motomu*; Ueta, Shinzo*
Abstracts P.510-511, p.510 - 511, 2004/00
Many studies have shown that colloidal particles which exist in ground water can facilitate radionuclide transport in subsurface environments. We conducted a series of laboratory experiments to investigate the effects of radionuclide sorption onto colloids and the surfaces of rock fractures. We focused on overall effects related to the kinetic behavior of those sorption processes. A mixed solution of cesium and clay colloids was injected into an artificially-created single fracture in a granite column. The fracture aperture and length are 0.5 mm and 50 cm, respectively. Numerical simulations were conducted to analyze the experiment results using a numerical code COLFRAC which can simulate colloid-facilitated solute transport in discretely-fractured porous media. The numerical formulation allows for either equilibrium or kinetic sorption onto the fracture walls, and the mobile and filtered colloidal particles. A series of experimental and numerical analyses shows that migration of cesium is facilitated by mobile colloidal particles which can sorb cesium and migrate in the fracture. The analyses also demonstrate that cesium migration is significantly enhanced if desorption of cesium from the colloids is a slow kinetic process and illustrate the importance of evaluating the parameters which describe such kinetic processes. Furthermore, radionuclide transport is likely to be retarded if mobile colloidal particles which sorb radionuclides are vigorously filtered on the fracture surfaces.
Kurosawa, Susumi; Ibaraki, Motomu*; Yui, Mikazu; Ueta, Shinzo*; Yoshikawa, Hideki
Materials Research Society Symposium Proceedings, Vol.824, 473 Pages, 2004/00
We conducted a series of laboratory experiments to investigate the effects of radionuclide sorption onto colloids and the surfaces of rock fractures. We focused on overall effects related to the kinetic behavior of those sorption processes. A mixed solution of cesium and clay colloids was injected into an artificially-created single fracture in a granite column. Numerical simulations were conducted to analyze the experiment results using a numerical code COLFRAC which can simulate colloid-facilitated solute transport in discretely-fractured porous media. A series of experimental and numerical analyses show that migration of cesium is facilitated by mobile colloidal particles which can sorb cesium and migrate in the fracture. The analyses also demonstrate that cesium migration is significantly enhanced if desorption of cesium from the colloids is a slow kinetic process and illustrate the importance of evaluating the parameters which describe such kinetic processes. Furthermore, radionuclide transport is likely to be retarded if mobile colloidal particles which sorb radionuclides are vigorously filtered on the fracture surfaces.
