Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Aihara, Jun; Kuroda, Masatoshi*; Tachibana, Yukio
Mechanical Engineering Journal (Internet), 9(4), p.21-00424_1 - 21-00424_13, 2022/08
It is important to improve oxidation resistance of fuel for huge oxygen ingress into core to improve safety of high temperature gas-cooled reactors (HTGRs), because almost volume of cores of HTGRs consist of graphite. In this study, simulated oxidation resistant fuel elements, of which matrix is mixture of SiC and graphite, has been fabricated by hot press method. In order to maintain structural integrity of fuel element under accident conditions, high-strength fuel elements should be developed. In order to identify optimal hot press conditions for preparing high-strength fuel elements, effect of hot press conditions on mechanical strength properties of fuel elements should be evaluated quantitatively. In the present study, response surface model, which represents relationship between hot press conditions and mechanical strength properties, has been constructed by introducing statistical design of experiments (DOE) approaches, and optimal hot press conditions were estimated by model.
Aihara, Jun; Kuroda, Masatoshi*; Tachibana, Yukio
Proceedings of 28th International Conference on Nuclear Engineering (ICONE 28) (Internet), 9 Pages, 2021/08
To maintain the structural integrity of fuel elements for a high-temperature gas-cooled reactor (HTGR) under disaster conditions, strong and oxidation-resistant fuel elements should be further developed. The HTGR fuel elements employ a hot-pressed silicon carbide (SiC)/carbon (C) mixed matrix to improve the oxidative resistance. Hot-press conditions such as pressure, temperature, and duration would be one of the factors that affect the strength of the HTGR fuel elements. To identify the optimal hot-press conditions for preparing the high-strength fuel elements, modelling their effects on the mechanical-strength properties of the HTGR fuel elements should be evaluated quantitatively. In this study, the response surface model, which represents the relationship between the hot-press conditions and the mechanical-strength properties, has been constructed by introducing statistical design-of-experiment approaches.
Aihara, Jun; Yasuda, Atsushi*; Ueta, Shohei; Ogawa, Hiroaki; Honda, Masaki*; Ohira, Koichi*; Tachibana, Yukio
Nihon Genshiryoku Gakkai Wabun Rombunshi, 18(4), p.237 - 245, 2019/12
Development of fabrication and inspection technologies of oxidation resistant fuel element for improvement of safety of high temperature gas-cooled reactors (HTGRs) in severe oxidation accident was carried out. Simulated coated fuel particles (CFPs), alumina particles, were over-coated with mixed powder of Si, C and small amount of resin to form over-coated particles, and over-coated particles were molded and hot-pressed to sinter simulated oxidation resistant fuel elements with SiC/C mixed matrix. Simulated oxidation resistant fuel elements with matrix whose Si/C mole ratio is 1.00 were fabricated. Failure fraction of CFPs in fuel elements is one of very important inspection subjects of HTGR fuel. It is essential that CFPs are extracted from fuel elements without additional failure. Development of method for extraction of CFPs was carried out. Desolation of SiC by KOH method or pressurized acidolysis method should be applied to extraction of CFPs.
Shibata, Taiju; Mizuta, Naoki; Sumita, Junya; Sakaba, Nariaki; Osaki, Takashi*; Kato, Hideki*; Izawa, Shoichi*; Muto, Takenori*; Gizatulin, S.*; Shaimerdenov, A.*; et al.
Proceedings of 9th International Topical Meeting on High Temperature Reactor Technology (HTR 2018) (USB Flash Drive), 7 Pages, 2018/10
Graphite materials are used for the in-core components of High Temperature Gas-cooled Reactor (HTGR). Oxidation damage on the graphite components in air ingress accident is a crucial issue for the safety point of view. SiC coating on graphite surface is a possible technique to enhance oxidation resistance. However, it is important to confirm the integrity of this material against high temperature and neutron irradiation for the application of the in-core components. JAEA and Japanese graphite companies carried out the R&D to develop the oxidation-resistant graphite. JAEA and INP investigated the irradiation effects on the oxidation-resistant graphite by using a framework of ISTC partner project. This paper describes the results of post irradiation experiment about the neutron irradiated SiC-coated oxidation-resistant graphite. A brand of oxidation-resistant graphite shows excellent performance against oxidation test after the irradiation.
Mizuta, Naoki; Sumita, Junya; Shibata, Taiju; Osaki, Takashi*; Kato, Hideki*; Izawa, Shoichi*; Muto, Takenori*; Gizatulin, S.*; Sakaba, Nariaki
Tanso Zairyo Kagaku No Shinten; Nihon Gakutsu Shinkokai Dai-117-Iinkai 70-Shunen Kinen-Shi, p.161 - 166, 2018/10
To enhance oxidation resistance of graphite material for in-core components of HTGR, JAEA and four Japanese graphite companies; Toyo Tanso, IBIDEN, Tokai Carbon and Nippon Techno-Carbon, are carrying out for development of oxidation-resistant graphite by CVD-SiC coating. This paper describes the outline of neutron irradiation test about the oxidation-resistant graphite by WWR-K reactor of INP, Kazakhstan through an ISTC partner project. Prior to the irradiation test, the oxidation-resistant graphite by CVD-SiC coating of all specimens showed enough oxidation resistance under un-irradiation condition. The neutron irradiation test was already completed and out-of-pile oxidation test will be carried out at the hot-laboratory of WWR-K.
Shibata, Taiju; Sumita, Junya; Sakaba, Nariaki; Osaki, Takashi*; Kato, Hideki*; Izawa, Shoichi*; Muto, Takenori*; Gizatulin, S.*; Shaimerdenov, A.*; Dyussambayev, D.*; et al.
Proceedings of 8th International Topical Meeting on High Temperature Reactor Technology (HTR 2016) (CD-ROM), p.567 - 571, 2016/11
Graphite are used for the in-core components of HTGR, and it is desirable to enhance oxidation resistance to keep much safety margin. SiC coating is the candidate method for this purpose. JAEA and four Japanese graphite companies are studying to develop oxidation-resistant graphite. Neutron irradiation test was carried out by WWR-K reactor of INP of Kazakhstan through ISTC partner project. The total irradiation cycles of WWR-K operation was 10 cycles by 200 days. Irradiation temperature about 1473 K would be attained. The maximum fast neutron fluence (E 
0.18 MeV) for the capsule irradiated at a central irradiation hole was preliminary calculated as 1.2
10
/m
, and for the capsule at a peripheral irradiation hole as 4.210
/m. Dimension and weight of the irradiated specimens were measured, and outer surface of the specimens were observed by optical microscope. For the irradiated oxidation resistant graphite, out-of-pile oxidation test will be carried out at an experimental laboratory.
Sato, Yoshiyuki*; Uchida, Munenori*; Kawamura, Hiroshi
JAERI-Conf 2004-006, p.203 - 209, 2004/03
no abstracts in English
-FeSi
) thin filmsSaito, Takeru; Yamamoto, Hiroyuki; Sasase, Masato*; Nakanoya, Takamitsu; Yamaguchi, Kenji; Haraguchi, Masaharu*; Hojo, Kiichi
Thin Solid Films, 415(1-2), p.138 - 142, 2002/08
Times Cited Count：20 Percentile：67.02(Materials Science, Multidisciplinary)no abstracts in English
Uwaba, Tomoyuki
JNC TN9420 2000-005, 28 Pages, 2000/03
JNC-TN9420-2000-005.pdf:0.94MB
In the first phase of the feasibility study, their basic objectives are presentating the feasible image and scenario of development of the FBR cycle system, which is composed of the fast reactor, spent fuel reprocessing and fuel manufacturing facility. In the development of the FBR system in this phase, various ideas of plants are to be studied, which include coolant types such as sodium, heavy metals, gases(CO, He), wator, and middle or small size of the reactor, and fuel types (MOX, metal and nitride). In this report, as a part of this study, materials used for the core of the helium gas cooled reactor and their integrity (corrosion, mechanical and irradiation property) under high temperature helium atmosphere were investigated from open literatures.
Nakano, Junichi; Fujii, Kimio; Shindo, Masami
JAERI-M 93-159, 20 Pages, 1993/08
no abstracts in English
Shindo, Masami
Keisha Kino Zairyo, 0(19), p.14 - 17, 1992/12
no abstracts in English
Imai, Hisashi; Fujii, Kimio; Nomura, Shinzo
High Temperature Corrosion of Advanced Materials and Protective Coatings, p.351 - 354, 1992/00
no abstracts in English
Imai, Hisashi; Fujii, Kimio; Nomura, Shinzo
Proc. of the 1st Int. Symp. on Functionally Gradient Materials, p.273 - 275, 1990/00
no abstracts in English
Shindo, Masami; Kondo, Tatsuo
JAERI-M 8835, 14 Pages, 1980/04
no abstracts in English
Goto, Minoru; Inaba, Yoshitomo; Aihara, Jun; Ueta, Shohei; Tachibana, Yukio
no journal, ,
JAEA has performed the research and development of the SiC matrix fuel, which is an oxidation resistant fuel against an air ingress accident, to establish the fundamental technologies. In this study, a nuclear thermal design was performed for the HTGR with the SiC matrix fuel.
Aihara, Jun; Ueta, Shohei; Honda, Masaki*; Ogawa, Hiroaki; Shibata, Taiju; Mizuta, Naoki; Inaba, Yoshitomo; Tachibana, Yukio
no journal, ,
Development of fabrication technology of fuel element of high temperature gas-cooled reactor with SiC/C mixed matrix was carried out to modify oxidation resistance. Dummy fuel elements with matrix, which Si/C ratio (about 0.551) was three times as large as those fabricated in precursor research, were fabricated. No Si peak was detected in XRD of matrix.
Kuroda, Masatoshi*; Tojo, Takuya*; Yamamoto, Takenori*; Aihara, Jun; Tachibana, Yukio
no journal, ,
High temperature gas-cooled reactor (HTGR) is a fourth generation nuclear reactor with inherent safety. In recent years, fuel elements with oxidation resistance has been developed for use in HTGR. In order to maintain the structural integrity of the oxidation resistant fuel element under accident conditions, a technique to fabricate a high-strength fuel should be required. In the present study, hot pressing conditions have been considered as the parameters which affect the strength of the oxidation resistant fuel compact, and a model has been created to predict the strength of the fuel compact from the hot pressing conditions by applying statistical approaches. The hot pressing conditions which can fabricate the high-strength oxidation resistant fuel element were also predicted by the model.
Tojo, Takuya*; Yamamoto, Takenori*; Kuroda, Masatoshi*; Aihara, Jun; Tachibana, Yukio
no journal, ,
Fuel compact of high-temperature gas-cooled reactor (HTGR) with inherent safety employs fuel component which was molded from graphite. Development of oxidation-resistant fuel component has been advancing at present, which is fuel component having oxidation resistance formed by SiC. In this study, mechanical properties were obtained on oxidation-resistant fuel components prepared under various molding parameters. Young's modulus was measured by ultrasonic pulse velocity test, and compressive strength was measured by compression test. High correlation was not observed between Young's modulus and hot pressing conditions of temperature and time. There was no correlation between compressive strength and hot pressing time in range of hot pressing temperature of 1573-1873 K and time of 40-120 min, but high negative correlation was observed within range of hot pressing temperatures. Therefore, it was predicted that compressive strength was increased by decreasing hot pressing temperature.
Tachibana, Yukio; Ohira, Koichi*; Kuroda, Masatoshi*
no journal, ,
For the purpose of upgrading safety of High Temperature Gas-cooled Reactor (HTGR), research on advanced fuel element was conducted with cooperation of Nuclear Fuel Industries and Kumamoto University. The advanced fuel element contains SiC as the matrix material and oxidation resistance is highly improved so that shape and integrity of the fuel element should be maintained even when large unexpected amount of air enters into the core in the air ingress (pipe rupture) accident which is a typical event for the HTGR. This presentation shows outlines of the contracted research from FY2014 to 2016.
Honda, Masaki*; Yasuda, Atsushi*; Ohira, Koichi*; Tachibana, Yukio
no journal, ,
For the purpose of upgrading safety of High Temperature Gas-cooled Reactor (HTGR), research on inspection technology for advanced fuel element was conducted with cooperation of JAEA from FY2014 to 2016. The advanced fuel element contains SiC as the matrix material and oxidation resistance is highly improved so that shape and integrity of the fuel element should be maintained even when large unexpected amount of air enters into the core in the air ingress (pipe rupture) accident which is a typical event for the HTGR. For the inspection technology, evaluation and inspection methods on homogeneity of SiC/C matrix and distribution of coated fuel particles as well as dissolution methods of coated fuel particles and SiC/C matrix for evaluation of failure fraction were developed and established.
