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Journal Articles

Current trends in nuclear energy, 4; European countries and international organizations

Hioki, Kazumasa; Sakurai, Satoshi

Nihon Genshiryoku Gakkai-Shi ATOMO$$Sigma$$, 56(2), p.34 - 38, 2014/02

no abstracts in English

JAEA Reports

Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage, 2; Progress report on NUMO-JAEA collaborative research in FY2012 (Joint research)

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.

JAEA Reports

Enhancement of the methodology of repository design and post-closure performance assessment for preliminary investigation stage; Progress report on NUMO-JAEA collaborative research in FY2011 (Joint research)

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.

Journal Articles

A Challenge on development of an advanced Knowledge Management System (KMS) for radioactive waste disposal; Moving from theory to practice

Makino, Hitoshi; Hioki, Kazumasa; Osawa, Hideaki; Semba, Takeshi; Umeki, Hiroyuki

New Research on Knowledge Management Technology, p.165 - 184, 2012/02

The paper will review progress to date of a challenge on development of an advanced Knowledge Management System (KMS) for radioactive waste disposal by JAEA, with emphasis on tailoring of existing knowledge engineering tools and methods to radioactive waste management requirements, and outline future developments and challenges.

JAEA Reports

CoolRep H22; Synthesis report on R&D results on geological disposal up to 2009

Umeki, Hiroyuki; Hioki, Kazumasa; Osawa, Hideaki; Fujita, Tomoo; Shibata, Masahiro; Makino, Hitoshi; Iwatsuki, Teruki; Takeuchi, Shinji; Ishimaru, Tsuneari

JAEA-Review 2010-073, 255 Pages, 2011/02

JAEA-Review-2010-073.pdf:4.19MB

The Japan Atomic Energy Agency (JAEA) has been performing research and development on geological disposal technology of high level radioactive waste. At the end of fiscal year 2009, the Geological Isolation Research and Development Directorate of JAEA made publicly available the "CoolRep H22", which is a web-based report that summarizes the R&D results, on its website. This document reports the contents of CoolRep H22.

Journal Articles

Common platform for communication among stakeholders using argumentation model for safety

Osawa, Hideaki; Hioki, Kazumasa; Makino, Hitoshi; Semba, Takeshi; Umeki, Hiroyuki; Takase, Hiroyasu*

Kenkyu, Gijutsu Keikaku Gakkai Dai-25-Kai Nenji Gakujutsu Taikai Oyobi Sokai Koen Yoshishu (CD-ROM), p.55 - 60, 2010/10

This paper describes new concept of common platform for communication among stakeholders using argumentation model for safety on geological disposal.

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.

Journal Articles

Use of the safety case to focus KMS application

Osawa, Hideaki; Hioki, Kazumasa; Umeki, Hiroyuki; Takase, Hiroyasu*; McKinley, I. G.*

Proceedings of 12th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '09/DECOM '09) (CD-ROM), 5 Pages, 2009/10

The paper will review progress to date in this work with illustrative examples of argumentation networks. An outline of future developments and challenges will also be provided, for example considering how confidence in arguments can be assessed, the weakest links in argumentation chains can be identified, arguments can be developed interactively at a level appropriate to all users, etc. Two companion papers demonstrate how these can be applied to critical areas of a repository programme, performance assessment and "geosynthesis". The link to the safety case forms a basis for decision making in the inevitable cases where conflicts between programme requirements arise. The long-term evolution of the safety case also forms a pathway for focusing the future challenges described in the final paper in this set.

Journal Articles

Practical application of the KMS, 1; Total system performance assessment

Makino, Hitoshi; Hioki, Kazumasa; Umeki, Hiroyuki; Yang, H.*; Takase, Hiroyasu*; McKinley, I. G.*

Proceedings of 12th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '09/DECOM '09) (CD-ROM), 8 Pages, 2009/10

This paper will outline the reformulation of PA as a Knowledge Management (KM) task, discuss application of knowledge management technologies to PA tasks, and illustrate how these can be handled electronically in a "Performance assessment All-In-one Report System (PAIRS)" utilising hyperlinks and embedded tools to minimise duplication of material, ease Quality Assurance (QA) and facilitate the regular updating required in the Japanese programme.

Journal Articles

Challenges for the JAEA KMS; Fostering inventive design and problem solving

Makino, Hitoshi; Hioki, Kazumasa; Umeki, Hiroyuki; Tachibana, Shoko*; Takase, Hiroyasu*; McKinley, I. G.*

Proceedings of 12th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '09/DECOM '09) (CD-ROM), 9 Pages, 2009/10

The JAEA Knowledge Management System (KMS) is being developed to be flexible and able to respond to potential changes of boundary conditions. On a shorter timescale, the KMS must encourage flexibility in the methodology used for carrying out and presenting performance assessments. This is closely linked to development of advanced repository concepts; considering the requirements for a safe and practical repository tailored to specific site conditions, which reflects evolving technology. These coupled development tasks were, in the past, carried out by expert teams in a rather informal manner. As the technical challenges increase - and the need for transparency is accepted - a more formal method of developing innovative design solutions is needed. A knowledge engineering approach (TRIZ) that is used in other financial and industrial applications has thus been tested for its usefulness for such tasks.

Journal Articles

Practical application of the KMS, 2; Site characterisation

Semba, Takeshi; Osawa, Hideaki; Hioki, Kazumasa; Tachibana, Shoko*; Takase, Hiroyasu*; McKinley, I. G.*

Proceedings of 12th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '09/DECOM '09) (CD-ROM), 8 Pages, 2009/10

To provide support for the Japanese implementer and also the regulator, a JAEA team is attempting to capture both Japanese and international geosynthesis experience within a KMS framework, which is termed ISIS. This is a hybrid system that combines "smart" software with human experts, although an aim is to capture tacit knowledge within expert systems to the maximum extent practicable. Initial tests, based mainly on field work carried out by JAEA at the sites of the Mizunami and Horonobe underground research laboratories.

Journal Articles

Overview of the JAEA knowledge management system supporting implementation and regulation of geological disposal in Japan

Umeki, Hiroyuki; Hioki, Kazumasa; Takase, Hiroyasu*; McKinley, I. G.*

Proceedings of 12th International Conference on Environmental Remediation and Radioactive Waste Management (ICEM '09/DECOM '09) (CD-ROM), 6 Pages, 2009/10

no abstracts in English

Journal Articles

The Challenge of development of a holistic waste management approach to support the Nuclear Renaissance

Makino, Hitoshi; Umeki, Hiroyuki; Hioki, Kazumasa; McKinley, I. G.*

Proceedings of International Waste Management Symposium 2009 (WM '09) (CD-ROM), 15 Pages, 2009/03

no abstracts in English

Journal Articles

IAEA radioactive waste safety standards; History, current status and future

Hioki, Kazumasa

Genankyo Dayori, (226), p.3 - 10, 2008/10

History, current status and the future of the IAEA Safety Standards on radioactive waste management is explained.

Journal Articles

JAEA Reports

Development of dynamic analysis method for Post-Accident event sequence

Hioki, Kazumasa

PNC TN9410 95-159, 54 Pages, 1995/05

PNC-TN9410-95-159.pdf:1.54MB

The process variables, the status of the components and the Human Error Probabilities (HEPs) affect each other. Therefore, it is necessary to dynamically calculate the process variables such as the temperature, the flow rate and the liquid level considering the HEPs and the components' status in order to evaluate the efficiency of the Accident Management (AM) including the Emergency Operating Procedures (EOPs). As the traditional methods with the event trees and the fault trees cannot deal with the event sequences dynamically, several dynamic methods have been proposed. These methods, however, cannot evaluate the efficiency of EOPs of real plants because of the large memory size and long calculation time which they need. A new dynamic analysis method for post accident event sequences is developed that utilizes the initiating events and the minimal cutsets which have already been obtained through the Level-1 PSA. By concentrating the objective to the evaluation of the efficiency of EOPs, this new method can deal with large systems including the support systems and real size plant within the limited computer memory in tolerable time.

JAEA Reports

Level-1 PSA on large fast breeder reactor (II); Evaluation of PLOHS frequency with the water steam system with decay heat removal capability

Hioki, Kazumasa

PNC TN9410 94-188, 160 Pages, 1994/05

PNC-TN9410-94-188.pdf:8.75MB

The Systems Analysis Section has been performing a probabilistic Safety Assessment (PSA) on a large fast breeder reactor (FBR) since JFY 1992. The objective of the study is to apply the PSA method to a plant in a conceptual design stage, develop system models, perform quantitative analyses and systematic evaluation, supply valuable insights to enhance reliability and safety, and reflect them to the basic design. The plant analyzed is a 600MWe class large FBR designed by the Plant Engineering Section in the "Large FBR design study" that has been performed since JFY 1990. The failure probability of the Decay Heat Removal System (DHRS) can be reduced approximately two orders if the Water Steam System (WSS) can remove the decay heat for the first 24 hours. The frequency of PLOHS, however, is not reduced to less than one third because the WSS cannot be used for some initiating events and the PLOHS frequency is dominated by the failure probability of DHRS without the WSS. The failure probability of DHRS is dominated by the common cause failures (CCFs) of vanes, dampers and valves around the air-coolers in the Auxiliary Cooling System (ACS). Therefore it is most important to eliminate the CCFs. Assuming that the CCFs have been eliminated by diversifying the components, the frequencies of PLOHS were evaluated. An analysis has shown that if the WSS can remove the decay heat alone, the PLOHS frequency is reduced approximately two orders. In this case the PLOHS frequency is dominated by the failure probability of the DHRS right after the reactor shutdown. The most effective way to reduce the PLOHS frequency is to increasc the redundancy of the DHRS for the first few hours after reactor shutdown. It is known through the experience of preceding plants that the success criteria can be relaxed to one loop natural circulation instead of forced circulation in the best estimate evaluation. It was shown that under such condition, the PLOHS frequency can be as low as 10$$^{-7}$$ ...

JAEA Reports

Level-1 PSA on large fast breeder reactor

Hioki, Kazumasa; ;

PNC TN9410 93-134, 223 Pages, 1993/05

PNC-TN9410-93-134.pdf:9.51MB

The Systems Analysis Section has performed a probabilistic Safety Assessment (PSA) on a large fast breeder reactor (FBR). The objective of the study is to apply the PSA method to a plant in a conceptual design stage, develop system models, perform quantitative analyses and systematic evaluation, supply valuable insights to enhance reliability and safety, and reflect them to the basic design. The plant analyzed is a 600MWe class large FBR designed by the Plant Engineering Section in the "Large FBR design study" that has been performed since JFY 1990. The report presents the results of level-1 PSA on internal events. The system models were constructed using fault trees and event trees and accident sequences which lead to core damage were identified and quantified. The systems and the components that are important to safety and the dominant accident sequences were identified based on the results of importance analyses and sensitivity studies. Insights were obtained through the systematic analyses that are effective for the enhancement of reliability and safety of the plant. As a result of the assessment based on the conceptual design the frequencies of LORL and ATWS are very low and the core damage frequency is dominated by PLOHS. The frequency of PLOHS is more than two orders of magnitude smaller based on the expected basic design and best estimate success criteria. The sensitivity study shows that the frequency decreases one more order if the Maintenance Cooling System has the same heat removal capability as one of the Auxiliary Cooling System loops.

JAEA Reports

Study on time-dependent unavailability evaluation

Hioki, Kazumasa

PNC TN9410 93-129, 88 Pages, 1993/05

PNC-TN9410-93-129.pdf:2.52MB

A method to evaluate time dependent unavailability of components and systems was developed and applied to a real-sized systems. With the component failure rate and the information on test and maintenance, the method first calculates the unavailability of each component included in minimal cutsets that is obtained through a fault tree analysis, and then calculates both the time-dependent and time-averaged unavailability of the system. It was shown that the method can be utilized to set a test schedule which gives higher reliability with the same manpower. Also shown is that the method can help develop the operational procedures such as the allowable outage time or the test intervals using the peak value instead of the time-averaged value of system unavailability.

Journal Articles

Development of Level-1 PSA Tools at PNC

Hioki, Kazumasa

Dai-2-Kai Nikkan, 0 Pages, 1993/00

None

49 (Records 1-20 displayed on this page)