Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Matsuba, Kenichi; Kamiyama, Kenji; Toyooka, Junichi; Tobita, Yoshiharu; Zuyev, V. A.*; Kolodeshnikov, A. A.*; Vassiliev, Y. S.*
Mechanical Engineering Journal (Internet), 3(3), p.15-00595_1 - 15-00595_8, 2016/06
To develop a method for evaluating the distance for fragmentation of molten core material discharged into sodium, the particle size distribution of alumina debris obtained in the FR tests was analyzed. The mass median diameters of solidified alumina particles were around 0.3 mm, which are comparable to particle sizes predicted by hydrodynamic instability theories such as Kelvin-Helmholtz instability. However, even though hydrodynamic instability theories predict that particle size decreases with an increase of Weber number, such the dependence of particle size on We was not observed in the FR tests. It can be interpreted that this tendency of measured mass median suggests that before hydrodynamic instabilities sufficiently grow to induce fragmentation, thermal phenomena such as local coolant vaporization and resultant vapor expansion accelerate fragmentation.
Matsuba, Kenichi; Kamiyama, Kenji; Toyooka, Junichi; Tobita, Yoshiharu; Zuev, V. A.*; Kolodeshnikov, A. A.*; Vasilyev, Y. S.*
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 6 Pages, 2015/05
To develop a method for evaluating the distance for fragmentation of molten core material discharged into sodium, the particle size distribution of alumina debris obtained in the FR tests was analyzed. The mass median diameters of solidified alumina particles were around 0.4 mm, which are comparable to particle sizes predicted by hydrodynamic instability theories such as Kelvin-Helmholtz instability. However, even though hydrodynamic instability theories predict that particle size decreases with an increase of Weber number, such the dependence of particle size on We was not observed in the FR tests. It can be interpreted that the tendency of measured mass median diameters (i.e., non-dependence on Weber number) suggests that before hydrodynamic instabilities sufficiently grow to induce fragmentation, thermal phenomena such as local coolant vaporization and resultant vapor expansion accelerate fragmentation.
Kamiyama, Kenji; Konishi, Kensuke; Sato, Ikken; Toyooka, Junichi; Matsuba, Kenichi; Suzuki, Toru; Tobita, Yoshiharu; Pakhnits, A. V.*; Vityuk, V. A.*; Vurim, A. D.*; et al.
Proceedings of 10th International Topical Meeting on Nuclear Thermal Hydraulics, Operation and Safety (NUTHOS-10) (USB Flash Drive), 8 Pages, 2014/12
Sato, Ikken; Tobita, Yoshiharu; Konishi, Kensuke; Kamiyama, Kenji; Toyooka, Junichi; Nakai, Ryodai; Kubo, Shigenobu*; Kotake, Shoji*; Koyama, Kazuya*; Vassiliev, Y. S.*; et al.
Journal of Nuclear Science and Technology, 48(4), p.556 - 566, 2011/03
In the JSFR design, elimination of severe recriticality events in the Core Disruptive Accident (CDA) is intended as an effective measure to assure retention of the core materials within the reactor vessel. The design strategy is to control the potential of excessive void reactivity insertion in the Initiating Phase selecting appropriate design parameters such as maximum void reactivity on one hand, and to exclude core-wide molten-fuel-pool formation, which has been the main issue of CDA, with introduction of Inner Duct on the other hand. The effectiveness of these measures are reviewed based on existing experimental data and evaluations performed with validated analysis tools. It is judged that the present JSFR design can exlude severe power burst events.
Tobita, Kenji; Nishio, Satoshi*; Enoeda, Mikio; Nakamura, Hirofumi; Hayashi, Takumi; Asakura, Nobuyuki; Uto, Hiroyasu; Tanigawa, Hiroyasu; Nishitani, Takeo; Isono, Takaaki; et al.
JAEA-Research 2010-019, 194 Pages, 2010/08
JAEA-Research-2010-019-01.pdf:48.47MBJAEA-Research-2010-019-02.pdf:19.4MB
This report describes the results of the conceptual design study of the SlimCS fusion DEMO reactor aiming at demonstrating fusion power production in a plant scale and allowing to assess the economic prospects of a fusion power plant. The design study has focused on a compact and low aspect ratio tokamak reactor concept with a reduced-sized central solenoid, which is novel compared with previous tokamak reactor concept such as SSTR (Steady State Tokamak Reactor). The reactor has the main parameters of a major radius of 5.5 m, aspect ratio of 2.6, elongation of 2.0, normalized beta of 4.3, fusion out put of 2.95 GW and average neutron wall load of 3 MW/m
. This report covers various aspects of design study including systemic design, physics design, torus configuration, blanket, superconducting magnet, maintenance and building, which were carried out increase the engineering feasibility of the concept.
Nakamura, Yukiharu; Tsutsui, Hiroaki*; Takei, Nahoko*; Shirai, Hiroshi; Sugihara, Masayoshi; Gribov, Y.*; Ozeki, Takahisa; Tobita, Kenji; Iio, Shunji*; Jardin, S. C.*
Journal of Plasma and Fusion Research SERIES, Vol.6, p.196 - 198, 2004/00
no abstracts in English
n eigenmodes driven by Alfnic beam ions in JT-60UShinohara, Koji; Kusama, Yoshinori; Takechi, Manabu; Morioka, Atsuhiko; Ishikawa, Masao*; Oyama, Naoyuki; Tobita, Kenji; Ozeki, Takahisa; Takeji, Satoru; Moriyama, Shinichi; et al.
Nuclear Fusion, 41(5), p.603 - 612, 2001/05
Times Cited Count：83 Percentile：90.44(Physics, Fluids & Plasmas)no abstracts in English
Kramer, G. J.; Iwase, Makoto; Kusama, Yoshinori; Morioka, Atsuhiko; Nemoto, Masahiro; Nishitani, Takeo; Shinohara, Koji; Takeji, Satoru; Tobita, Kenji; Ozeki, Takahisa; et al.
Nuclear Fusion, 40(7), p.1383 - 1396, 2000/07
Times Cited Count：46 Percentile：77.78(Physics, Fluids & Plasmas)no abstracts in English
Saito, Yasushi*; Hibiki, Takashi*; Mishima, Kaichiro*; Tobita, Y.*; Suzuki, Toru*; Matsubayashi, Masahito
Proceedings of 9th International Symposium on Flow Visualization, p.391_1 - 391_10, 2000/00
no abstracts in English
n eigenmodes, burst modes and chirping modes in the Alfvn frequency range driven by negative ion based neutral beam injection in JT-60UKusama, Yoshinori; Kramer, G. J.; Kimura, Haruyuki; Saigusa, Mikio*; Ozeki, Takahisa; Tobita, Kenji; Oikawa, Toshihiro; Shinohara, Koji; Kondoh, Takashi; Moriyama, Shinichi; et al.
Nuclear Fusion, 39(11Y), p.1837 - 1843, 1999/11
Times Cited Count：68 Percentile：87.07(Physics, Fluids & Plasmas)no abstracts in English
n eigenmodes and their coupling to global Alfvn eigenmodesKramer, G. J.; Cheng, C. Z.*; Fu, G. Y.*; Kusama, Yoshinori; Nazikian, R. M.*; Ozeki, Takahisa; Tobita, Kenji
Physical Review Letters, 83(15), p.2961 - 2964, 1999/10
Times Cited Count：24 Percentile：75.07(Physics, Multidisciplinary)no abstracts in English
Mishima, Kaichiro*; Hibiki, Takashi*; Saito, Y.*; Nishihara, Hideaki*; Tobita, Y.*; *; Matsubayashi, Masahito
Nuclear Instruments and Methods in Physics Research A, 424(1), p.229 - 234, 1999/00
Times Cited Count：31 Percentile：88.42(Instruments & Instrumentation)no abstracts in English
Kusama, Yoshinori; Fu, G. Y.*; Kramer, G. J.*; Saigusa, Mikio*; Oikawa, Toshihiro; Ozeki, Takahisa; Moriyama, Shinichi; Tchernychev, F. V.*; Nemoto, Masahiro; Kondoh, Takashi; et al.
Plasma Physics and Controlled Fusion, 41(9), p.1167 - 1177, 1999/00
Times Cited Count：5 Percentile：20.12(Physics, Fluids & Plasmas)no abstracts in English
n eigenmodes and their impact on plasma characteristics in JT-60UKusama, Yoshinori; Nazikian, R.*; Kramer, G. J.*; Kimura, Haruyuki; Saigusa, Mikio*; Ozeki, Takahisa; Fu, G. Y.*; Tobita, Kenji; Oikawa, Toshihiro; Shinohara, Koji; et al.
Fusion Energy 1998, 2, p.537 - 544, 1998/10
no abstracts in English
Kimura, Haruyuki; Kusama, Yoshinori; Saigusa, Mikio*; Kramer, G. J.*; Tobita, Kenji; Nemoto, Masahiro; Kondoh, Takashi; Nishitani, Takeo; O.DaCosta*; Ozeki, Takahisa; et al.
Nuclear Fusion, 38(9), p.1303 - 1314, 1998/09
Times Cited Count：126 Percentile：95.17(Physics, Fluids & Plasmas)no abstracts in English
Kusama, Yoshinori; Kimura, Haruyuki; Ozeki, Takahisa; Saigusa, Mikio*; Kramer, G. J.*; Oikawa, Toshihiro; Moriyama, Shinichi; Nemoto, Masahiro; Fujita, Takaaki; Tobita, Kenji; et al.
Nuclear Fusion, 38(8), p.1215 - 1223, 1998/08
Times Cited Count：41 Percentile：76.66(Physics, Fluids & Plasmas)no abstracts in English
Kramer, G. J.*; Saigusa, Mikio; Ozeki, Takahisa; Kusama, Yoshinori; Kimura, Haruyuki; Oikawa, Toshihiro; G.Y.Fu*; C.Z.Cheng*; Tobita, Kenji
Physical Review Letters, 80(12), p.2594 - 2597, 1998/03
Times Cited Count：45 Percentile：83.75(Physics, Multidisciplinary)no abstracts in English
Kimura, Haruyuki; Moriyama, Shinichi; Saigusa, Mikio; Kusama, Yoshinori; Ozeki, Takahisa; Kramer, G. J.*; Fujita, Takaaki; Oikawa, Toshihiro; Fujii, Tsuneyuki; Nemoto, Masahiro; et al.
Fusion Energy 1996, Vol.3, p.295 - 305, 1997/00
no abstracts in English
Kamiyama, Kenji; Konishi, Kensuke; Sato, Ikken; Matsuba, Kenichi; Tobita, Yoshiharu; Toyooka, Junichi; Pakhnits, A. V.*; Vityuk, V.*; Kukushkin, I.*; Vurim, A. D.*; et al.
no journal, ,
no abstracts in English
Matsuba, Kenichi; Kamiyama, Kenji; Tobita, Yoshiharu; Toyooka, Junichi; Zuev, V.*; Kolodeshnikov, A.*; Vasilyev, Y.*
no journal, ,
In order to obtain experimental knowledge on fragmentation behavior of molten core material discharged into the lower sodium plenum in the reactor vessel during core disruptive accidents of sodium cooled fast reactors, a series of fragmentation experiments have been carried out with a molten oxide. Based on the experimental results, dominant mechanisms for the fragmentation behavior was discussed.
Kubo, Shigenobu; Tobita, Yoshiharu; Sato, Ikken; Kotake, Shoji*; Endo, Hiroshi*; Koyama, Kazuya*; Konishi, Kensuke; Kamiyama, Kenji; Matsuba, Kenichi; Toyooka, Junichi; et al.
no journal, ,
As the results of good collaboration between Kazakhstan and Japan in EAGLE-1and 2, it was shown that there exists a solution to the recriticality issue of SFR, which has been one of the major safety issues for more than a half century from the beginning of the SFR development. Experimental techniques and facilities have been developed for the SFR severe accident study. Since 2014, JAEA participates the ASTRID program in which severe accident study is one of important issues. The EAGLE-1 and 2 data will be also used as an essential part of the severe accident study for ASTRID. EAGLE-3 was just started from beginning of 2015. Points of experiments moved into the later phase of core damage process, i.e., material relocation and cooling after achieving neutronic shutdown. A number of out-of-pile tests and in-pile tests are planned in coming five years.
