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Ishibashi, Ryo*; Hirosaka, Kazuma*; Yamana, Takashi*; Shibata, Masatoshi*; Sasaki, Masana*; Nemoto, Yoshiyuki; Hinoki, Tatsuya*
Proceedings of TopFuel 2024 (Internet), 9 Pages, 2024/09
Takeda, Tetsuaki*; Inagaki, Yoshiyuki; Aihara, Jun; Aoki, Takeshi; Fujiwara, Yusuke; Fukaya, Yuji; Goto, Minoru; Ho, H. Q.; Iigaki, Kazuhiko; Imai, Yoshiyuki; et al.
High Temperature Gas-Cooled Reactors; JSME Series in Thermal and Nuclear Power Generation, Vol.5, 464 Pages, 2021/02
As a general overview of the research and development of a High Temperature Gas-cooled Reactor (HTGR) in JAEA, this book describes the achievements by the High Temperature Engineering Test Reactor (HTTR) on the designs, key component technologies such as fuel, reactor internals, high temperature components, etc., and operational experience such as rise-to-power tests, high temperature operation at 950
C, safety demonstration tests, etc. In addition, based on the knowledge of the HTTR, the development of designs and component technologies such as high performance fuel, helium gas turbine and hydrogen production by IS process for commercial HTGRs are described. These results are very useful for the future development of HTGRs. This book is published as one of a series of technical books on fossil fuel and nuclear energy systems by the Power Energy Systems Division of the Japan Society of Mechanical Engineers.
Aoki, So; Kondo, Keietsu; Kaji, Yoshiyuki; Yamamoto, Masahiro
Proceedings of the 18th International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, Vol.2, p.663 - 672, 2018/00
Times Cited Count：2 Percentile：53.04(Materials Science, Multidisciplinary)The objective of this study was to clarify effect of long-term thermal aging on SCC initiation susceptibility in low carbon austenitic stainless steels. Specimens used were Type 304L and 316L steels. Both steels were cold rolled to 20% thickness reduction (CW) and then followed by long-term thermal aging at 288C for 14,000 h (LTA). Crevice Bent Beam (CBB) test was carried out to estimate the SCC initiation susceptibility under BWR simulated water condition at high temperature. The present results of the CBB tests showed that 304L CW + LTA exhibited no SCC susceptibility. In contrast, the SCC initiation susceptibility of 316L increased by the combination of cold rolling and long-term thermal aging. To understand these results, evaluation on the changes in microchemistry, microstructure and mechanical properties induced by the CW and LTA treatment has been developed, and their correlation with the SCC initiation susceptibility is discussed.
Seki, Masayuki; Kihara, Yoshiyuki; Kaito, Takeji; Tsukada, Tatsuya*; Motoki, Kazuhiko*; Hirako, Kazuhito*
Proceedings of International Conference on Toward and Over the Fukushima Daiichi Accident (GLOBAL 2011) (CD-ROM), 5 Pages, 2011/12
Oxide Dispersion Strengthened (ODS) steel has been developed as an advanced fuel cladding tube for sodium cooled fast reactors in Japan Atomic Energy Agency (JAEA) to attain the target burn up of 150 GWd/t in the bundle average because of its excellent swelling resistance and high mechanical strength in high temperature. If conventional TIG welding is applied to the ODS welding, it is difficult to obtain necessary mechanical strength at the weld zone because of the formation of porosity. It is formed by the argon bubbles which initially dissolve in the matrix and grow up under the high temperature during welding. Therefore JAEA has been conducted the development of pressurized resistance welding (PRW) technology for ODS cladding tube, which is one of the solid state welding methods. This paper describes in the development of PRW technology, an ultrasonic test method for detecting weld defects, the result of machine strength measurement examination in weld part and the result of fuel pin irradiation examination using nuclear reactor.
collisions at 
= 200 and 62.4 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Armendariz, R.*; et al.
Physical Review C, 83(6), p.064903_1 - 064903_29, 2011/06
Times Cited Count：193 Percentile：99.41(Physics, Nuclear)Transverse momentum distributions and yields for 
, and 
in collisions at = 200 and 62.4 GeV at midrapidity are measured by the PHENIX experiment at the RHIC. We present the inverse slope parameter, mean transverse momentum, and yield per unit rapidity at each energy, and compare them to other measurements at different collisions. We also present the scaling properties such as 
and 
scaling and discuss the mechanism of the particle production in collisions. The measured spectra are compared to next-to-leading order perturbative QCD calculations.
Okubo, Tsutomu; Oki, Shigeo; Ogura, Masashi*; Okubo, Yoshiyuki*; Kotake, Shoji*
Proceedings of 2011 International Congress on Advances in Nuclear Power Plants (ICAPP '11) (CD-ROM), p.479 - 486, 2011/05
A conceptual design study and related R&D on a commercial-base large-scale Japan Sodium-cooled Fast Reactor (JSFR) have been carried out in the framework of the Fast Reactor Cycle Technology development (FaCT) project. As a next generation plant, JSFR adopts a number of innovative technologies in order to achieve economic competitiveness, enhanced reliability and safety. This paper describes the current results of the ongoing conceptual design study on the JSFR core. The most important point in the core design is to achieve a high core average burn-up around 150 GWd/t, assuming the ODS steel utilization as the cladding material. Another design target for the breeding ratio is intended to have some flexibility and is set at from around 1.0 to 1.2 under the design philosophy of the compatible fuel assembly among them. Also, the fuel composition is considered to have some variation range based on the wide variety of the spent fuel composition expected to be treated during the LWR to FBR transition period. The core design study performed in the FaCT project has clarified the feasibility of the JSFR core concept, which is based on the high internal conversion ratio type core using a large fuel rod diameter around 10 mm and satisfies a number of design targets and requirements including ones mentioned above.
and Au+Au collisions at 
= 200 GeVAdare, A.*; Afanasiev, S.*; Aidala, C.*; Ajitanand, N. N.*; Akiba, Yasuyuki*; Al-Bataineh, H.*; Alexander, J.*; Aoki, Kazuya*; Aphecetche, L.*; Aramaki, Y.*; et al.
Physical Review C, 83(4), p.044912_1 - 044912_16, 2011/04
Times Cited Count：10 Percentile：54.53(Physics, Nuclear)Measurements of electrons from the decay of open-heavy-flavor mesons have shown that the yields are suppressed in Au+Au collisions compared to expectations from binary-scaled collisions. Here we extend these studies to two particle correlations where one particle is an electron from the decay of a heavy flavor meson and the other is a charged hadron from either the decay of the heavy meson or from jet fragmentation. These measurements provide more detailed information about the interaction between heavy quarks and the quark-gluon matter. We find the away-side-jet shape and yield to be modified in Au+Au collisions compared to collisions.
trappingIshimori, Kenichiro; Kameo, Yutaka; Matsue, Hideaki; Oki, Yoshiyuki*; Nakashima, Mikio; Takahashi, Kuniaki
Applied Radiation and Isotopes, 69(2), p.506 - 510, 2011/02
Times Cited Count：6 Percentile：42.22(Chemistry, Inorganic & Nuclear)In order to establish a simple and rapid analytical method for 
C in solidified products made from non-metallic low-level radioactive solid wastes by melting treatment, a radiochemical analysis in combination with alkaline fusion as a sample decomposition method was examined. A simulated solidified product containing C, which was prepared by using nuclear reaction N(n, p)C with thermal neutron irradiation, was analyzed by the present method to compare with a conventional radiochemical analysis using oxidizing combustion. The reproducible and quantitative recovery of C from the simulated solidified product indicates that the present method is superior and more efficient for C analysis in solidified products than the conventional method using oxidizing combustion.
Inagaki, Yaohiro*; Sakatani, Keiichi*; Yamamura, Yuki*; Mitsui, Seiichiro; Noshita, Kenji*; Miura, Yoshiyuki*; Kanehira, Norio*; Ochi, Eiji*; Mukunoki, Atsushi*; Chiba, Tamotsu*
Dai-7-Kai Saishori, Risaikuru Bukai Semina Tekisuto, p.136 - 137, 2011/01
Conventional static test methods are not appropriate to evaluate glass dissolution behavior at an arbitrarily-fixed condition due to compositional change of the solution with glass dissolution. In this study, we applied a newly-devised micro-channel flow-through test method to measurement of the initial dissolution rates of Japanese simulated waste glasses, JAEA-P0798 and JNFL-KMOC, at arbitrarily-fixed conditions and we evaluated temperature and pH dependence of glass dissolution. The results showed that the initial dissolution rate increased with temperature and had "V-shaped" pH dependence at each temperature.
-ray emitting nuclides (Joint research)Ishimori, Kenichiro; Oki, Keiichi; Takaizumi, Hirohide; Kameo, Yutaka; Oki, Yoshiyuki*; Nakashima, Mikio
JAEA-Technology 2007-065, 20 Pages, 2008/01
JAEA-Technology-2007-065.pdf:1.4MB
In order to prepare a reference material which is used for radiochemical analysis of solidified products made from non-metallic miscellaneous low level radioactive solid wastes by melting in Nuclear Science Research Institute, Japan Atomic Energy Agency, the preparation method of the reference material was investigated. Under the optimum melting conditions obtained in this report, the reference material containing 
Np, 
Am and 
Cm as -ray emitting nuclides was successfully prepared. From radiochemical analysis of the reference material, the radioactive concentration of respective nuclides was determined to be 0.188
0.001 Bq/g for Np, 0.3680.004 Bq/g for Am, 0.4020.010 Bq/g for Cm.
Kawamura, Kenji*; Parrenin, F.*; Lisiecki, L.*; Uemura, Ryu*; Vimeux, F.*; Severinghaus, J. P.*; Hutterli, M. A.*; Nakazawa, Takakiyo*; Aoki, Shuji*; Jouzel, J.*; et al.
Nature, 448(7156), p.912 - 916, 2007/08
Times Cited Count：360 Percentile：96.61(Multidisciplinary Sciences)We present a new chronology of Antarctic climate change over the past 360,000 years that is based on the ratio of oxygen to nitrogen molecules in air trapped in the Dome Fuji and Vostok ice cores. This ratio is a proxy for local summer insolation, and thus allows the chronology to be constructed by orbital tuning without the need to assume a lag between a climate record and an orbital parameter. The accuracy of the chronology allows us to examine the phase relationships between climate records from the ice cores and changes in insolation. Our results indicate that orbital-scale Antarctic climate change lags Northern Hemisphere insolation by a few millennia, and that the increases in Antarctic temperature and atmospheric carbon dioxide concentration during the last four terminations occurred within the rising phase of Northern Hemisphere summer insolation. These results support the Milankovitch theory that Northern Hemisphere summer insolation triggered the last four deglaciations.
Sato, Satoshi; Yamauchi, Michinori; Nishitani, Takeo; Ioki, Kimihiro; Iida, Hiromasa; Kataoka, Yoshiyuki
JAEA-Technology 2006-032, 91 Pages, 2006/03
JAEA-Technology-2006-032.pdf:12.8MB
no abstracts in English
Shimomura, Yasuo; Tsunematsu, Toshihide; Yamamoto, Shin; Maruyama, So; Mizoguchi, Tadanori*; Takahashi, Yoshikazu; Yoshida, Kiyoshi; Kitamura, Kazunori*; Ioki, Kimihiro*; Inoue, Takashi; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 78(Suppl.), 224 Pages, 2002/01
no abstracts in English
Inagaki, Yoshiyuki; Fujimoto, Nozomu; Motoki, Yasuo; Iyoku, Tatsuo; Maruyama, So; Shiozawa, Shusaku
JAERI-M 90-223, 30 Pages, 1990/12
no abstracts in English
Yokoo, Hiroki*; Kawamoto, Keisuke*; Oki, Takumi*; Uehara, Motoki*; Onuki, Toshihiko*; Ohara, Yoshiyuki; Fukuyama, Kenjin; Hochella, M. F. Jr.*
no journal, ,
no abstracts in English
Ishibashi, Ryo*; Hirosaka, Kazuma*; Yamana, Teppei*; Shibata, Masatoshi*; Sasaki, Masana*; Yasuda, Kenichi*; Nemoto, Yoshiyuki; Hinoki, Tatsuya*
no journal, ,
no abstracts in English
Ishibashi, Ryo*; Sasaki, Masana*; Shibata, Masatoshi*; Yasuda, Kenichi*; Nemoto, Yoshiyuki; Hinoki, Tatsuya*
no journal, ,
CIshimori, Kenichiro; Oki, Keiichi; Kameo, Yutaka; Takaizumi, Hirohide; Nakashima, Mikio; Oki, Yoshiyuki*; Isogai, Keisuke*
no journal, ,
no abstracts in English
Kaji, Yoshiyuki; Kondo, Keietsu; Aoki, So; Hirade, Tetsuya; Yamamoto, Masahiro
no journal, ,
To clarify the causal relationship between the LTA treatment and the SCC initiation susceptibility, microstructural analyses on 316L CW specimens before and after the LTA treatment have been conducted. One of viewpoints in our research is the deformation microstructure. Results of the surface examination by SEM on CBB tested specimens suggested the difference in the deformation microstructure of 316L CW and CW+LTA. Coarse and planar slip steps were frequently observed on the surface of 316L CW+LTA specimens, indicating the localization of dislocation motion to limited slip planes. On the other hand, surface morphology observed in 316L CW was mainly fine and wavy slip step, indicating the occurrence of the homogeneous plastic deformation. The detail mechanism of the change in the deformation microstructure by the LTA treatment is unknown yet. Researches on its effect on the deformation microstructure and, furthermore, the SCC susceptibility is now in progress.
Aoki, So; Kondo, Keietsu; Kaji, Yoshiyuki; Yamamoto, Masahiro
no journal, ,
The objective of this study was to clarify stress corrosion cracking (SCC) initiation susceptibility and corrosion behavior of grain boundaries of long-term thermal aged low carbon austenitic stainless steels in simulated BWR condition. Crevice Bent Beam (CBB) test was carried out to estimate the SCC initiation susceptibility under BWR simulated water condition. Surface and grain boundaries analysis of specimens was also carried out after the CBB test. The present results of the CBB tests showed that the SCC initiation susceptibility of Type 316L increased clearly by the combination of the cold work and the long-term thermal aging. Grain boundaries of Type 316L specimen which exhibited the SCC initiation susceptibility corroded with formation of Cr oxide, and the oxide formed along depth direction of grain boundaries. Based on these results, the correlation among SCC initiation susceptibility, SCC crack initiation and corroded grain boundaries will be discussed.
