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Nagase, Fumihisa; Ishikawa, Jun; Kurata, Masaki; Yoshida, Hiroyuki; Kaji, Yoshiyuki; Shibamoto, Yasuteru; Amaya, Masaki; Okumura, Keisuke; Katsuyama, Jinya
Proceedings of International Nuclear Fuel Cycle Conference; Nuclear Energy at a Crossroads (GLOBAL 2013) (CD-ROM), p.711 - 720, 2013/09
Estimation of the accident progress and status inside the reactor is required to properly and reliably conduct decommissioning of the Fukushima-Daiichi NPPs. For that, it is necessary to obtain additional experimental data and revised models for the estimation using computer codes with increased accuracies. JAEA has selected phenomena to be reviewed and developed in terms of thermo hydraulic behavior in the reactor, progression of fuel bundle degradation, failure of the lower head of the reactor pressure vessel, and analysis of the accident, considering previously obtained information, conditions specific to the Fukushima-Daiichi NPP accident, and recent progress of experimental and analytical technologies. This paper introduces the selected phenomena to be reviewed and developed and recent results from the JAEA's corresponding research programs.
113 of the 113th elementMorita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Haba, Hiromitsu*; Ozeki, Kazutaka*; Kudo, Yuki*; Sumita, Takayuki*; Wakabayashi, Yasuo*; Yoneda, Akira*; Tanaka, Kengo*; et al.
Journal of the Physical Society of Japan, 81(10), p.103201_1 - 103201_4, 2012/10
Times Cited Count：167 Percentile：97.31(Physics, Multidisciplinary)An isotope of the 113th element, 113, was produced in a nuclear reaction with a 
Zn beam on a 
Bi target. We observed six consecutive 
decays following the implantation of a heavy particle in nearly the same position in the semiconductor detector, in extremely low background condition. The fifth and sixth decays are fully consistent with the sequential decays of 
Db and 
Lr both in decay energies and decay times. This indicates that the present decay chain consisted of 113, 
Rg (Z = 111), 
Mt (Z = 109), 
Bh (Z = 107), Db (Z = 105), and Lr (Z = 103) with firm connections. This result, together with previously reported results from 2004 and 2007, conclusively leads the unambiguous production and identification of the isotope 113, of the 113th element.
Kanaya, Toshiji*; Takahashi, Nobuaki; Takeshita, Hiroki*; Okura, Masatoshi*; Nishida, Koji*; Kaji, Keisuke*
Polymer Journal, 44(1), p.83 - 94, 2012/01
Times Cited Count：28 Percentile：68(Polymer Science)Takahashi, Nobuaki; Kanaya, Toshiji; Nishida, Koji*; Kaji, Keisuke*
Macromolecules, 40(24), p.8750 - 8755, 2007/11
Times Cited Count：17 Percentile：47.77(Polymer Science)Time-resolved light scattering measurements have been performed on poly(vinyl alcohol) (PVA) in mixed solvents of dimethyl sulfoxide (DMSO) and water with various mixing ratios after quenching from 100
C to 25C to examine physical gelation process. A broad scattering peak characteristic to phase separation appeared in the light scattering profiles after a certain incubation time (
) and the peak position 
moved to higher with annealing time. The results contradict the theoretical predictions and experimental observations for usual phase separation systems, suggesting effects of gelation (or network formation) on the phase separation. The growth kinetics significantly depend on the mixing ratio of DMSO and water, showing that the solvent quality is also a factor to affect the phase separation kinetics during the physical gelation process. The unusual phase separation kinetics is discussed in terms of gelation-induced phase separation.
112 by 
Pb + Zn reactionMorita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kudo, Hisaaki*; et al.
Journal of the Physical Society of Japan, 76(4), p.043201_1 - 043201_5, 2007/04
Times Cited Count：151 Percentile：95.96(Physics, Multidisciplinary)The production and decay of 112 has been investigated using a gas-filled recoil ion separator in irradiations of Pb targets with Zn beam at 349.5 MeV. We have observed two -decay chains that can be assigned to subsequent decays from 112 produced in the 208 Pb(Zn,n) reaction. After emitting four consecutive -particles, the both chains ended by spontaneous fission decays of 
Rf and decay energies and decay times of the both chains obtained in the present work agree well with those reported by a group at Gesellschaft f
r Schwerionenforschung (GSI), Germany. The present result gives the first clear confirmation of the discovery of 112 and its -decay products 
Ds reported previously.
113Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Katori, Kenji*; Koura, Hiroyuki; Kikunaga, Hidetoshi*; et al.
Journal of the Physical Society of Japan, 76(4), p.045001_1 - 045001_2, 2007/04
Times Cited Count：199 Percentile：97.42(Physics, Multidisciplinary)The production and decay of 113 has been investigated using a gas-filled recoil ion separator in irradiations of Bi targets with Zn beam at 353 MeV. We have observed one -decay chain that can be assigned to subsequent decays from 113 produced in the Bi(Zn,n) reaction. After emitting four consecutive -particles, the both chains ended by spontaneous fission decays of Db and decay energies and decay times of the both chains obtained in the present work agree well with those reported by our group in 2004. The present result gives the first clear confirmation of the discovery of 113 and its -decay products Rg reported previously.
Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Kanungo, R.*; Katori, Kenji*; Kikunaga, Hidetoshi*; et al.
AIP Conference Proceedings 891, p.3 - 9, 2007/03
A series of experiments studying the productions and their decays of the heaviest elements have been performed by using a gas-filled recoil separator GARIS at RIKEN. Results on the isotope of the 112th element, 112, and on that of the 113th element, 113, are reviewed. Two decay chains which are assigned to be ones originating from the isotope 112 were observed in the Pb(Zn, n) reaction. The results provide a confirmation of the production and decay of the isotope 112 reported by a research group at GSI, Germany, produced via the same reaction by using a velocity filter. Two decay chains, both consisted of four consecutive alpha decays followed by a spontaneous fission, were observed also in the reaction Bi(Zn, n). Those are assigned to be the convincing candidate events of the isotope of the 113th element, 113, and its daughter nuclei. Rg, Mt, Bh, and Db.
Bi(Zn,n)113Morita, Kosuke*; Morimoto, Koji*; Kaji, Daiya*; Akiyama, Takahiro*; Goto, Shinichi*; Haba, Hiromitsu*; Ideguchi, Eiji*; Kanungo, R.*; Katori, Kenji*; Koura, Hiroyuki; et al.
Journal of the Physical Society of Japan, 73(10), p.2593 - 2596, 2004/10
Times Cited Count：487 Percentile：99.22(Physics, Multidisciplinary)The isotope of the 113th element, 113, and its daughter nuclei, 111 and Mt, were obserbed, for the first time, in the Bi + Zn reaction at a beam energy of 349.1 MeV with a total dose of 1.6
10
. The production cross section of 113 is deduced to be 
fb (
cm
).
Goto, Shinichi*; Kaji, D.*; Nishinaka, Ichiro; Nagame, Yuichiro; Ichikawa, Shinichi; Tsukada, Kazuaki; Asai, Masato; Haba, Hiromitsu; Mitsuoka, Shinichi; Nishio, Katsuhisa; et al.
Journal of Radioanalytical and Nuclear Chemistry, 255(1), p.73 - 76, 2003/01
Times Cited Count：0 Percentile：0.01(Chemistry, Analytical)no abstracts in English
Nagame, Yuichiro; Zhao, Y.*; Nishinaka, Ichiro; Goto, Shinichi*; Kaji, D.*; Tanikawa, Masashi*; Tsukada, Kazuaki; Asai, Masato; Haba, Hiromitsu; Sakama, Minoru*; et al.
Radiochimica Acta, 89(11-12), p.681 - 688, 2002/02
Times Cited Count：3 Percentile：27.07(Chemistry, Inorganic & Nuclear)no abstracts in English
