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Journal Articles

Development of under sodium viewer for next generation sodium-cooled Fast reactor; Imaging test in sodium

Aizawa, Kosuke; Chikazawa, Yoshitaka; Ara, Kuniaki; Yui, Masahiro*; Jinno, Kentaro*; Hiramatsu, Takashi*

Proceedings of 2019 International Congress on Advances in Nuclear Power Plants (ICAPP 2019) (Internet), 7 Pages, 2019/05

Inspection technique in opaque liquid metal coolant is one of important issues for sodium-cooled fast reactors. Various under sodium viewers (USVs), including horizontal USVs for obstacle detection and imaging USVs, have been developed in several research institutes and countries. We aim practical realization of imaging USV which adopts an optical receiving system, which measures the vibration displacement of diaphragm by using a laser as a receiving sensor. This study mainly focuses on the sensitivity improvement of a receiving sensor. An issue for the sensitivity improvement of the receiving sensor is the sound pressure propagation inside the receiving sensor. Prototype tests in the water and sodium were conducted in order to resolve the issue. In addition, imaging experiments in the water and sodium were conducted using the improved receiving sensor. From the results of imaging experiments, the relation between obtained wave profile and the regeneration imaging was confirmed.

Journal Articles

Development of under sodium viewer for next generation sodium-cooled fast reactors

Aizawa, Kosuke; Chikazawa, Yoshitaka; Ara, Kuniaki; Yui, Masahiro*; Uemoto, Yohei*; Kurokawa, Masaaki*; Hiramatsu, Takashi*

Proceedings of International Conference on Fast Reactors and Related Fuel Cycles; Next Generation Nuclear Systems for Sustainable Development (FR-17) (USB Flash Drive), 9 Pages, 2017/06

Inspection in opaque liquid metal coolant is one of important issues for sodium-cooled fast reactors. To facilitate operations and maintenance activities, various under sodium viewers (USVs), including horizontal USVs for obstacle detection for a long distance and imaging USVs for a short and middle distance imaging, have been developed in several research institutes and countries. In this study, an imaging USV for a middle distance, approximately 1 m, has been developed. The USV in this study adopts an optical receiving system which measures the vibration displacement of diaphragm by using a laser as a receiving sensor. This study mainly focuses on the sensitivity improvement for a transmission sensor and the receiving sensor. In addition, an imaging experiment in the water was conducted using the new transmission sensor and receiving sensor. The experimental results showed that the newly developed USV sensors can make higher resolution images of a target than the previous sensors.

Journal Articles

Studies on maintainability and repairability for Japan Sodium-cooled Fast Reactor (JSFR)

Isono, Kenichi; Kubo, Shigenobu; Chikazawa, Yoshitaka; Dozaki, Koji*; Oya, Takeaki*; Yui, Masahiro*

Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 7 Pages, 2014/07

Aiming at enabling maintenance and repair of almost all components in JSFR demonstration reactor to a level equivalent to that attained for the light water reactors, we identified a number of parts which have difficulty in maintenance and repair in main components of the reactor structure and the primary/secondary main coolant system. And we defined the criteria for design improvement and then provided candidates of improvement measures for the identified parts. Furthermore, we made a modification of the plant design in a consistent manner integrating the improvements investigated for each major component. A series of evaluations were conducted to check the feasibility as a power plant. As the result, we found that the concept could be adopted not only to the demonstration reactor (750 MWe) but to the commercial one (1500 MWe).

JAEA Reports

Horonobe Underground Research Laboratory Project; Synthesis of phase I investigation 2001 - 2005, Volume "Geological disposal research"

Fujita, Tomo; Taniguchi, Naoki; Matsui, Hiroya; Tanai, Kenji; Maekawa, Keisuke; Sawada, Atsushi; Makino, Hitoshi; Sasamoto, Hiroshi; Yoshikawa, Hideki; Shibata, Masahiro; et al.

JAEA-Research 2011-001, 193 Pages, 2011/03

JAEA-Research-2011-001.pdf:5.23MB

This report summarizes the progress of research and development on geological disposal during the surface-based investigation phase (2001-2005) in the Horonobe Underground Research Laboratory project, of which aims are to apply the design methods of geological disposal and mass transport analysis to actual geological conditions obtained from the surface-based investigations in the Horonobe Underground Research Laboratory project as an example of actual geological environment.

JAEA Reports

Information basis for developing comprehensive waste management system; US-Japan Joint Nuclear Energy Action Plan Waste Management Working Group Phase I report (Joint research)

Yui, Mikazu; Ishikawa, Hirohisa; Watanabe, Atsuo*; Yoshino, Kyoji*; Umeki, Hiroyuki; Hioki, Kazumasa; Naito, Morimasa; Seo, Toshihiro; Makino, Hitoshi; Oda, Chie; et al.

JAEA-Research 2010-015, 106 Pages, 2010/05

JAEA-Research-2010-015.pdf:13.58MB

This report summarizes the activity of Phase I of Waste Management Working Group of the United States - Japan Joint Nuclear Energy Action Plan started in 2007. The working group focused on consolidation of the existing technical basis between the U.S. and Japan and the joint development of a plan for future collaborative activities. Firstly, the political/regulatory frameworks related to nuclear fuel cycles in both countries were reviewed. The various advanced fuel cycle scenarios in both countries were surveyed and summarized. Secondly, the waste management/disposal system optimization was discussed. Repository system concepts for the various classifications of nuclear waste were reviewed and summarized, then disposal system optimization processes and techniques were reviewed, and factors to consider in future repository design optimization activities were also discussed. Finally the potential collaboration areas and activities related to the optimization problem were extracted.

JAEA Reports

Investigations on systematics of thermodynamic data and comparison of estimation of solubility values among different activity coefficient models for development of thermodynamic database

Kitamura, Akira; Shibata, Masahiro; Yamaguchi, Tetsuji; Iida, Yoshihisa; Yui, Mikazu

JAEA-Technology 2009-074, 48 Pages, 2010/03

JAEA-Technology-2009-074.pdf:7.33MB

Investigations on systematics of thermodynamic data were performed for performance assessment of geological disposal of high-level and TRU waste. Correlation between standard free energy of formation and standard enthalpy of formation was investigated, and it was shown that estimation of the standard enthalpy of formation from the standard free energy of formation was possible using the correlation. Three models on systematics of formation constant of actinides were compared and the best model was proposed. It was shown that estimation of formation constant for unpublished species was possible using the model. Furthermore, two models for estimation of activity coefficient which was required to estimate solubility of elements of interest and the estimated activity coefficient were compared. It was expected that the obtained results were useful for the performance assessment of geological disposal.

JAEA Reports

Evaluating and categorizing the reliability of distribution coefficient values in the sorption database

Ochs, M.*; Saito, Yoshihiko; Kitamura, Akira; Shibata, Masahiro; Sasamoto, Hiroshi; Yui, Mikazu

JAEA-Technology 2007-011, 342 Pages, 2007/03

JAEA-Technology-2007-011.pdf:24.24MB

Japan Atomic Energy Agency (JAEA) has developed the sorption database (SDB) for bentonite and rocks in order to assess the retardation property of important radioactive elements in natural and engineered barriers in the H12 report. The database includes distribution coefficient (K$$_{d}$$) of important radionuclides. The K$$_{d}$$ values in the SDB are about 20,000 data. The SDB includes a great variety of K$$_{d}$$ and additional key information from many different literatures. Accordingly, the following classification guideline and classification system were developed in order to evaluate the reliability of each K$$_{d}$$ value (Th, Pa, U, Np, Pu, Am, Cm, Cs, Ra, Se, Tc on bentonite). The reliability of 3740 K$$_{d}$$ values are evaluated and categorized.

JAEA Reports

Horonobe Underground Research Laboratory project synthesis of phase I investigation 2001-2005 volume "Geological Disposal Research"

Fujita, Tomo; Taniguchi, Naoki; Matsui, Hiroya; Tanai, Kenji; Nishimura, Mayuka; Kobayashi, Yasushi; Hiramoto, Masayuki; Maekawa, Keisuke; Sawada, Atsushi; Makino, Hitoshi; et al.

JAEA-Research 2007-045, 140 Pages, 2007/03

JAEA-Research-2007-045-1.pdf:38.33MB
JAEA-Research-2007-045-2.pdf:44.62MB

This report summarizes the progress of research and development on geological disposal during the surface-based investigation phase (2001-2005) in the Horonobe Underground Research Laboratory project (HOR), of which aims are to apply the design methods of geological disposal and mass transport analysis to actual geological environments and derive future subjects based on the results. The design methods of geological disposal were reviewed based on the recent knowledge and the advertences were identified. Then the parameters for virtual design of engineered barrier system, backfill deposition hole and tunnel were set up based on actual geological conditions obtained from the surface-based investigations in HOR as an example of actual geological environment. The conceptual structure from site investigation and evaluation to mass transport analysis was represented as a work flow at first. Then following this work flow a series of procedures for mass transport analysis were carried out based on actual geological conditions obtained from the surface-based investigations in HOR to illustrate the functioning of the work flow and the applicability of this methodology. Consequently, knowledge that will help follow-up or future execution and planning activities was obtained.

JAEA Reports

Study on diffusion depth of matrix in granitic rock

Tochigi, Yoshikatsu; Kogawa, Noritaka*; Mukai, Satoru*; Jintoku, Takashi*; Sasamoto, Hiroshi; Shibata, Masahiro; Yui, Mikazu

JAEA-Research 2007-024, 27 Pages, 2007/03

JAEA-Research-2007-024.pdf:1.83MB

In the safety assessment of high-level radioactive waste (HLW) geological disposal, it is important to understand diffusion behavior of radionuclides for evaluation of retardation capacity in the host rock. In this study, non steady state diffusion experiments with non-sorbing ion ware carried out using several granitic rock samples of different length and the matrix diffusion depth was evaluated. As the results of experiment, it is confirmed that the non-sorbing ion can diffuse into the unaltered zone of granitic rock at least about 200 mm in depth and almost same diffusion coefficient is estimated for all rock samples independent of length. Based on these results, it is expected that matrix diffusion of nuclides is acting on a scale of several dozens of centimeters in the granitic rock.

JAEA Reports

The Study plan on applicability to actual geological environment conditions of the engineering technology for geological disposal of high level nuclear-waste through the second phases in Horonobe Underground Research Project

Aoyanagi, Shigeo; Yui, Mikazu; Tanai, Kenji; Kawakami, Susumu; Fujita, Tomo; Taniguchi, Naoki; Shibata, Masahiro; Konishi, Kazuhiro; Nishimura, Mayuka; Kikuchi, Hirohito*; et al.

JAEA-Review 2006-014, 61 Pages, 2006/03

JAEA-Review-2006-014.pdf:5.03MB

no abstracts in English

JAEA Reports

Diffusivity Database (DDB) system for major rocks; Version of 2006/Specification and CD-ROM

Tochigi, Yoshikatsu; Sasamoto, Hiroshi; Shibata, Masahiro; Sato, Haruo; Yui, Mikazu

JAEA-Data/Code 2006-008, 16 Pages, 2006/03

JAEA-Data-Code-2006-008.pdf:1.15MB

The development of the database system has been started to manage with the generally used. The database system has been constructed based on datasheets of the effective diffusion coefficient of the nuclides in the rock matrix in order to be applied on the "H12: Project to Establish the Scientific and Technical Basis for HLW Disposal in Japan". In this document, the examination and expansion of the datasheet structure and the process of construction of the database system and conversion of all data existing on datasheets are described. As the first step of the development of the database, this database system and its data will continue to be updated and the interface will be revised to improve the availability. The developed database system is attached on the CD-ROM as the file format of Microsoft Access.

Journal Articles

Current status of system development to provide the databases of nuclides migration

Sasamoto, Hiroshi; Yoshida, Yasushi*; Isogai, Takeshi*; Suyama, Tadahiro*; Jintoku, Takashi*; Shibata, Masahiro; Yui, Mikazu

Saikuru Kiko Giho, (28), p.27 - 33, 2005/09

JNC has developed the databases of nuclides migration for safety assessment of high-level radioactive waste (HLW), and the databases have been used in the second progress report to present the technical reliability of HLW geological disposal in Japan. The technical level and applicability of databases developed by JNC have been evaluated highly not only in Japan but also in overseas. Thus we have performed the followings in order to provide the databases broadly in the word and to promote the use of databases; 1) development of tools to convert the database format from geochemical code PHREEQE to PHREEQC, GWB and EQ3/6, 2) open the web site including the databases to the public. As a result, a down-load system of databases from web site has been applied and the database users have significantly increased. Additionally it has been performed that we consider the useful comments from database user for modification and/or update of databases.

JAEA Reports

Development of Guideline for Evaluating and Categorizing the Reliability of Distribution Coefficient Values in the JNC-Sorption Database

Yoshihiko, Saito,; Ochs, M.*; Jintoku, Takashi*; Suyama, Tadahiro*; Shibata, Masahiro; Sasamoto, Hiroshi; Yui, Mikazu

JNC TN8410 2005-011, 59 Pages, 2005/08

JNC-TN8410-2005-011.pdf:2.04MB

Japan Nuclear Cycle Development Institute (JNC) has developed the JNC-Sorption Database (JNC-SDB) for bentonite and rocks in order to assess the retardation property of important radioactive elements in natural and engineered barriers in the H12 report. The database includes distribution coefficient (Kd) of important radionuclides. The Kd values in the JNC-SDB are about 20,000 data. And the JNC-SDB includes a great variety of Kd and additional key information from many different experimental conditions. Accordingly, the following classification guideline and classification system were developed in order to evaluate the reliability of each Kd value. (1) Criterion I: Completeness of documentation and type of Kd information (2) Criterion II: Quality of reported data from a technical and scientific point of view (3) Criterion III: Consistency of data with the majority of related reliable studies (4) An overall classification system / The checkpoints in Criterion II evaluate the reliability of each Kd entry in the JNC-SDB ; solid phase, adjustment and control of pH, redox conditions, final solution composition, temperature, solid/water ratio and grain size, sorption value, initial radionuclide concentration, phase separation, reaction time, agitation method, radionuclide loading, reaction vessels, uncertainty estimates, parameter variation

JAEA Reports

Development of Thermodynamic Databases for Hyperalkaline, Argillaceous Systems

Arthur, R. C,*; Sasamoto, Hiroshi; Oda, Chie; Honda, Akira; Shibata, Masahiro; Yoshida, Yasushi*; Yui, Mikazu

JNC TN8400 2005-010, 234 Pages, 2005/07

JNC-TN8400-2005-010.pdf:11.24MB

This report describes three thermodynamic databases for minerals, gases, aqueous species and reactions of relevance to bentonite and cement barriers in geologic repositories for transuranic (TRU) and other nuclear wastes. The databases support calculations using the SUPCRT, PHREEQC and GWB geochemical codes, and are referred to as SPRONS.TRU (SUPCRT), JNC-TDB.TRU (PHREEQC) and THERMO_ JNCTRU (GWB). The reliability of these databases should be considered in the context of basic limitations in current conceptual models of clay-bearing, high-pH systems. Minerals that are important in such systems tend to be complex, possibly metastable solid solutions having highly variable compositions that have not been well characterized experimentally or thermodynamically. There is also considerable uncertainty regarding important aqueous species in such systems due to the paucity of relevant experimental data presently available. With these limitations in mind, the databases developed in this study are considered to be reliable insofar as they include data for minerals that are known to be important or representative of hyperalkaline, argillaceous systems, and because the data are in general demonstrably accurate in cases where comparisons can be made between calculated values and their experimental counterparts. The databases may not meet the ideal standard of an internally consistent database because more weight has been given in this study to the accuracy and completeness of the data than to their internal consistency. An approach recommended for future improvements and revisions of the databases described in this report includes the development of a consistent set of empirical methods permitting routine estimation of thermodynamic properties in cases where reliable experimental data are lacking, combined with uncertainty analyses to assess the importance of conceptual and parameter uncertainties on models of the long-term behavior of bentonite and cementitious barriers.

JAEA Reports

Status of Assessment Techniques for Long-Term Stability of Buffer Material

Shibata, Masahiro; Sasamoto, Hiroshi; Jintoku, Takashi; Yui, Mikazu

JNC TN8400 2004-010, 46 Pages, 2004/03

JNC-TN8400-2004-010.pdf:14.26MB

This report presents the assessment for long-term stability of buffer material considering the possible alteration scenarios under repository conditions based on the recent research results (i.e., H12) about bentonite alteration. In the assessment, the following three effects have a priority in view points of performance assessment: 1) temperature effect, 2) interaction effect with overpack as a engineered barrier material, 3) interaction effect with cement as support materials of the dritf in soft rock. Four cases were selected in combination with geological environment in the assessment considering the temperature effect and effects with near-field components.

JAEA Reports

ENTRY 2003 - The International Workshop on Reliable Performance Assessment through Laboratory Experiments and Ground Surface Investigations - 10th Anniversary of ENTRY

Ishikawa, Hirohisa; Yui, Mikazu; Uchida, Masahiro; Kamei, Gento

JNC TN8200 2003-004, 151 Pages, 2004/03

JNC-TN8200-2003-004.pdf:1.89MB

To commemorate the 10th anniversary of the ENTRY, a laboratory in JNC Tokai for R&D in the field of geological disposal of radioactive waste, an international workshop was held in JNC Tokai, during the term of Sept 22 to 24, 2003. A technical tour for the Horonobe Underground Research Laboratory site was also done before the workshop, on October 20 to 21, to deepen understanding the background of discussion in the workshop.The workshop contained two sessions. The topic of each session was 1. long-term transition of the near-field and 2. cooperation among the performance assessment, in-situ experiment, and laboratory experiment, respectively. In the session 1, we mainly discussed the thermal-hydrological-mechanical-chemical (THMC) coupled processes for the near-field performance assessment, especially focusing on chemical degradation effects by cement materials and the status of mechanistic understanding radionuclide migration. Silicate dissolution kinetic model, including smectite dissolution in a hyper alkaline solution, was also discussed. Then, we discussed a relevant linkage among laboratory experiments, model (simulation experiment) and database development, in-situ experiment and natural analogue.In the session 2, we discussed (1) methodology for understanding the site based on the surface and boreholes investigations, (2) identification of remained uncertainty after the surface and boreholes investigations, (3) the critical measurement at the surface and boreholes investigations, (4) feedback items from performance assessment to site characterization and (5) required data besides the site investigation. This report contains the minutes of discussion in the workshop. Presented materials were also appended with permission from the speakers.

Journal Articles

None

Kamei, Gento; Ishikawa, Hirohisa; Yui, Mikazu; Uchida, Masahiro; Aoki, Kazuhiro

Saikuru Kiko Giho, (21), p.95 - 98, 2003/12

None

JAEA Reports

Thermodynamic Database for NH$$_{2}$$-Species of Radioactive Elements

Ochs, M.*; Lothenbach, B.*; Christl, I.*; Yui, Mikazu; Shibata, Masahiro; Jintoku, Takashi

JNC TN8400 2003-012, 28 Pages, 2003/06

JNC-TN8400-2003-012.pdf:1.81MB

In the original list of ligands to be considered in the JNC-TDB, NH$$_{3}$$ had not been included, but NH$$_{3}$$, complexes were evaluated for Pd due to their importance for such soft acid metals. Presently, NH$$_{3}$$- complexes are considered to be important for the Japanese TRU disposal program, because nitrate contained in this type of waste could possibly be reduced to NH$$_{3}$$ under repository conditions. This report presents thermodynamic data that are particularly critical for evaluating the safety functions of the repository near field, but are also of general importance for performance analysis. An extensive data search and initial evaluation for the interaction of NH$$_{3}$$ with Pb, Sn, Bi, Nb, and Sb were carried out, but yielded no useful results. Therefore, no thermodynamic data can be recommended for NH$$_{3}$$-species of these elements. However, the compiled information allowed a rough comparative evaluation of stability constants in the system NH$$_{3}$$ - H$$_{2}$$O - Metal, which indicates that NH$$_{3}$$ is not likely to be a critical ligand for Sn(IV), Bi, Nb, and Sb(V) in dilute solutions. For Pb, complexation with NH$$_{3}$$ may become relevant at elevated NH$$_{3}$$ concentrations. Our evaluation further indicated that NH$$_{3}$$ could be a relevant ligand for Ni and Co. Their interaction with NH$$_{3}$$ had been studied to some degree. Subsequently, a first, traceable compilation of original experimental data was carried out for Ni and Co. However, in most case, the possible complex formation of Ni with the anions of the electrolyte and OH$$^{-}$$ has not been considered in the calculations of the different constants. It remains to be studied in detail whether these interactions can be neglected or corrected for in all cases. A brief attempt was made to carry out some calculations for Ni in order to roughly estimate possible effect of the presence of NH$$_{3}$$ on a repository performance. The calculations carried out clearly show that very high NH$$_{3}$$ ...

Journal Articles

Applicability of Thermodynamic Database of Radioactive Elements Developed for the Japanese Performance Assessment of HLW Repository

Yui, Mikazu; Rai, D.*; Ochs, M.*; Shibata, Masahiro

Journal of Nuclear Science and Technology, 40(5), p.356 - 362, 2003/00

 Times Cited Count:4 Percentile:32.68(Nuclear Science & Technology)

None

JAEA Reports

None

Tochiyama, Osamu*; Niibori, Yuichi*; *; *; Yui, Mikazu; Shibata, Masahiro; *

JNC TY8400 2002-014, 129 Pages, 2002/05

JNC-TY8400-2002-014.pdf:2.35MB

None

44 (Records 1-20 displayed on this page)