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Ishikawa, Koki; Takamatsu, Misao; Kawahara, Hirotaka; Mihara, Takatsugu; Kurisaka, Kenichi; Terano, Toshihiro; Murakami, Takanori; Noritsugi, Akihiro; Iseki, Atsushi; Saito, Takakazu; et al.
JAEA-Technology 2009-004, 140 Pages, 2009/05
JAEA-Technology-2009-004.pdf:2.0MB
Probabilistic safety assessment (PSA) has been applied to nuclear plants as a method to achieve effective safety regulation and safety management. In order to establish the PSA standard for fast breeder reactor (FBR), the FBR-PSA for internal events in rated power operation is studied by Japan Atomic Energy Agency (JAEA). The level1 PSA on the experimental fast reactor Joyo was conducted to investigate core damage probability for internal events with taking human factors effect and dependent failures into account. The result of this study shows that the core damage probability of Joyo is 5.0
10
per reactor year (/ry) and that the core damage probability is smaller than the safety goal for existed plants (10 ry) and future plants (10
/ry) in the IAEA INSAG-12 (International Nuclear Safety Advisory Group) basic safety principle.
Matsuba, Kenichi; Ito, Chikara; Kawahara, Hirotaka; Aoyama, Takafumi
Journal of Power and Energy Systems (Internet), 2(2), p.545 - 556, 2008/00
Significant thermal stresses are loaded onto the structures of sodium-cooled fast reactor (SFR) due to high temperature and large temperature gradients associated with employing sodium coolant with its high thermal conductivity and low heat capacity. Therefore, it is important to monitor the temperature variation, related stress and displacement, and vibration in the cooling system piping and components in order to assure structural integrity while the reactor plant is in-service. SFR structural integrity monitoring can be enhanced by an optical fiber sensor, which is capable of continuous or dispersed distribution measurements of various properties such as radiation dose, temperature, strain, displacement and acceleration. In the experimental fast reactor Joyo, displacement and vibration measurements of the primary cooling system have been carried out using Fiber Bragg Grating (FBG) sensors to evaluate the durability and measurement accuracy of FBG sensors in a high 
-ray environment. The data were successfully obtained with no significant signal loss up to an accumulated -ray dose of approximately 410
Gy corresponding to 120 EFPDs operation. Measured displacement of the piping support was nearly equal to the calculated thermal displacement. Measured vibration power spectra of the piping support were similar to those measured with a reference acceleration sensor. The measured results indicate that the FBG sensor is suitable for monitoring the displacement and vibration aspects of fast reactor cooling system integrity in a high -ray environment.
Matsuba, Kenichi; Ito, Chikara; Kawahara, Hirotaka; Aoyama, Takafumi
Dai-12-Kai Doryoku, Enerugi Gijutsu Shimpojiumu Koen Rombunshu, p.13 - 14, 2007/06
no abstracts in English
Matsuba, Kenichi; Ito, Chikara; Kawahara, Hirotaka; Aoyama, Takafumi
Proceedings of 15th International Conference on Nuclear Engineering (ICONE-15) (CD-ROM), 8 Pages, 2007/04
Significant thermal stresses are loaded on the structures of sodium-cooled fast reactor (SFR) due to high temperature and large temperature gradients associated with employing sodium coolant. Therefore, it is important to monitor the temperature variation and related stress on the cooling system piping in order to assure structural integrity. Structural integrity monitoring can be enhanced by an optical fiber sensor, which is capable of continuous or dispersed distribution measurements of various physical properties such as radiation dose, temperature, strain, displacement and acceleration. In the experimental fast reactor Joyo, displacement and vibration measurements of the primary cooling system have been carried out using Fiber Bragg Grating (FBG) sensors to evaluate the durability and measurement accuracy of FBG sensors in a high ray environment. The data were successfully obtained with no significant signal loss up to an accumulated ray dose of approximately 410Gy corresponding to 120EFPDs operation. Measured displacement of the piping support was nearly equal to the calculated thermal displacement. Measured vibration power spectra of the piping support were similar to those measured with a reference acceleration sensor. The measured results indicate that the FBG sensor is applicable for monitoring the displacement and vibration of fast reactor cooling system integrity in a high ray environment.
Matsuba, Kenichi; Kawahara, Hirotaka; Aoyama, Takafumi
JAEA-Conf 2006-003, p.24 - 37, 2006/05
The experimental fast reactor JOYO at O-arai Engineering Center of Japan Nuclear Cycle Development Institute is the first liquid metal cooled fast reactor in Japan. This paper describes the plant outline, experiences on the fast reactor technology and test results accumulated through twenty eight years successful operation of JOYO.
Matsuba, Kenichi; Kawahara, Hirotaka; Ito, Chikara; Yoshida, Akihiro; Nakai, Satoru
UTNL-R-0453, p.12_1 - 12_10, 2006/03
no abstracts in English
Kataoka, Shinichi*; Kawahara, Kenichi*; Matsunaga, Kenichi*; Ishihara, Yoshinao*; Neyama, Atsushi*; Nakagawa, Koichi*; Iwata, Hiroshi*; Mori, Koji*
JNC TJ8400 2001-037, 33 Pages, 2001/03
JNC-TJ8400-2001-037.pdf:2.02MB
no abstracts in English
Kataoka, Shinichi*; Kawahara, Kenichi*; Matsunaga, Kenichi*; Ishihara, Yoshinao*; Neyama, Atsushi*; Nakagawa, Koichi*; Iwata, Hiroshi*; Mori, Koji*
JNC TJ8400 2001-036, 202 Pages, 2001/03
JNC-TJ8400-2001-036.pdf:7.58MB
The newest literature information in the foreign countries was researched, and this research showed the basic concept of the coupling analysis code to realize coupling analysis in near field of the geological disposal system. The outline of this research is shown in the following. (1)The combination of M (Mechanical) and (Chemistry) is placed on the weak relations, Because coupling analysis of the United States Yucca Mountain limits a site and the specifications of engineered barrier. (2)One of the purposes of this research is information collecting about coupling analysis code NUFT-C adopted in the United States Yucca Mountain. Therefore, we carried out an information exchange with the United States Lawrence Livermore National Laboratory. We could collect the development purpose of analysis code, key function, and information such as a test case analysis. (3)The investigation of the analysis code concerned with the newest information of coupling analysis which contains the geochemistry process and 2 phase system was done based on the public information for the purpose of building some concept of the coupling analysis code, the extraction of the development issues. It could be understood about the future development strategy and the precaution in addition to a phenomenon to deal with, the current status of the coupling analysis technique as a result of the investigation. (4)It was cleared about the mission of the coupling analysis code and the requirement items (function, quality) by this research. Then, some development options were presented. (5)It was studied about the procedure of developing it to satisfy the above requirement toward the conditions that a site isn't selected, the short development. The tool (Diffpack) which could cope with the speed-up of the calculation time and visualization flexibly was effective, and it was summarized about the test case by using this tool, the key function of this tool as that result.
Ishihara, Yoshinao*; Matsuoka, Fushiki*; Sagawa, Hiroshi*; Kawahara, Kenichi*; Kataoka, Shinichi*; Shinohara, Yoshinori*; Muroi, Masayuki*; Tsuchiya, Makoto*; Tsujimoto, Keiichi*; Ohashi, Toyo*
JNC TJ8400 2001-011, 259 Pages, 2001/03
JNC-TJ8400-2001-011.pdf:0.99MB
In this study, the basic design study on integrated computer system has been carried out in order to develop the integrated methodologies for future research and development activities of geological disposal system. The key conclusions are summarized as follows: (1) As the result of the investigation of work items and associated flow of information (data) between items in the second progress report by JNC, the interaction matrix and work flow chart have been identified in order to specify the basic configuration of the integrated computer system. In addition, the model chain and the structure of data relation between the repository design study and safety assessment study have been summarized. (2)We organized and examined the system factor and the information process flow in the design, safety analysis, and geological environment study based on the 2000 Report by JNC. Then we analyzed the workflow of geological disposal business when a specific site for a repository is fixed to obtain the system factor and the information process flow. We consider the fracture/porous media, site location (land/under the sea), and long-term stability of the crust (upheaval/sink) as the key factors in examining the workflow of geological disposal business. Then we organized the information change between the design and other study in geological disposal based on the 2000 Report by JNC. We examined the ideal workflow in which the design, safety analysis, and geologic environment study of geological disposal are closely coupled. We examined the scientific and technical base of the knowledge base (the system factor and the information process flow) which is derived from the above to construct the hierarchical structure of the knowledge base for geological disposal. (3)As the result of the interaction matrix and work flow chart for the R&D activities, the conceptual design and the function diagram on the integrated computer system has been proposed. (4)We examined the plan to ...
*; *; Kawahara, Kenichi*; *; *; *; *
JNC TJ8400 99-051, 61 Pages, 1999/02
In this study, a research and development plan for overpacks has been proposed by identifying issues for developing overpacks and organizing approaches for resolving them, as well as investigating a structural design methodology for overpacks and a quality control method in manufacturing them. The results are summarized as follows: (1)Technical Requirements for overpacks. Tentative technical requirements for overpacks are summarized on the survey of overseas literatures and performance assessment models discussed so far. (2)Determination of Reference Design. Handling and manufacturing methods for overpacks are discussed. Reference overpack structures are determined considering the discussion on the structural strength. (3)Approach to assuring structural integrity of overpacks. Load conditions and rupture modes after backfill are reviewed. A structural design methodology for overpacks was discussed based on FEM analyses. In addition, inspection items, which are necessary to assure that technical requirements are satisfied. (4)Destructive test. Destructive test is carried out in order to validate FEM analysis and others for basing a structural design methodology. As a consequence of the test, we could verify the sufficient reliability of FEM analysis and conservatism of the design methodology. (5)Quality control method. R&D items for quality control of overpacks are summarized based on the ideas of the order No. 73 issued by the Prime Minister's Office. Validation of measurement reliability for ultrasonic tests is the major R&D items in the future. (6)Preparation for R&D plan. A R&D plan for developing technical criteria for overpacks is summarized.
*; *; Kawahara, Kenichi*; *; *; *; *
JNC TJ8400 99-050, 310 Pages, 1999/02
In this study; a research and development plan for overpacks has been proposed by identifying issues for developing overpacks and organizing approaches for resolving them, as well as investigating a structural design methodology for overpacks and a quality control method in manufacturing them. The results are summarized as follows: (1)Technical Requirements for overpacks. Tentative technical requirements for overpacks are summarized on the survey of overseas literatures and performance assessment models discussed so far. (2)Determination of Reference Design. Handling and manufacturing methods for overpacks are discussed. Reference overpack structures are determined considering the discussion on the structural strength. (3)Approach to assuring structural integrity of overpacks. Load conditions and rupture modes after backfill are reviewed. A structural design methodology for overpacks was discussed based on FEM analyses. In addition, inspection items, which are necessary to assure that technical requirements are satisfied. (4)Destructive test. Destructive test is carried out in order to validate FEM analysis and others for basing a structural design methodology. As a consequence of the test, we could verify the sufficient reliability of FEM analysis and conservatism of the design methodology. (5)Quality control method. R&D items for quality control of overpacks are summarized based on the ideas of the order No. 78 issued by the Prime Minister's Office. Validation of measurement reliability for ultrasonic tests is the major R&D items in the future. (6)Preparation for R&D plan. A R&D plan for developing technical criteria, for overpacks is summarized.
Ito, Kunihiro*; Kinjo, Hidehito*; Aoi, Sadanori*; Kawahara, Kenichi*; Seino, Shun*
PNC TJ2214 90-001, 118 Pages, 1990/08
no abstracts in English
Matsuba, Kenichi; Kawahara, Hirotaka; Aoyama, Takafumi
no journal, ,
In JOYO, strain and vibration multi-point measurements of the primary cooling system piping have been carried out using a Fiber Bragg Graing (FBG) sensor. Through these measurements, applicability of a FBG sensor in a low-radiation environment was confirmed.
Matsuba, Kenichi; Ito, Chikara; Kawahara, Hirotaka
no journal, ,
no abstracts in English
Matsuba, Kenichi; Ito, Chikara; Kawahara, Hirotaka
no journal, ,
no abstracts in English
Kawahara, Hirotaka; Iseki, Atsushi; Yamazaki, Manabu; Yamamoto, Masaya; Takamatsu, Misao; Ishikawa, Koki; Kurisaka, Kenichi; Aoyama, Takafumi
no journal, ,
no abstracts in English
