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by means of synchrotron radiation X-ray photoelectron spectroscopyIwase, Akihiro*; Ono, Hirotaka*; Ishikawa, Norito; Baba, Yuji; Hirao, Norie; Sonoda, Takeshi*; Kinoshita, Motoyasu*
Nuclear Instruments and Methods in Physics Research B, 267(6), p.969 - 972, 2009/03
Times Cited Count：39 Percentile：90.80(Instruments & Instrumentation)To study the effects of swift heavy ion irradiation on cerium dioxide (CeO), CeO sintered pellets were irradiated with 200 MeV Xe ions at room temperature. For irradiated and unirradiated samples, the spectra of X-ray photoelectron spectroscopy (XPS) were measured. XPS spectra for the irradiated samples show that the valence state of Ce atoms partly changes from +4 to +3. The amount of Ce
state was quantitatively obtained as a function of ion-fluence. The relative amount of oxygen atom displacements, which are accompanied by the decrease in Ce valence state, is 3-5%. This value is too large to be explained in terms of elastic interactions between CeO and 200 MeV ions. The experimental result suggests the contribution of 200 MeV Xe induced electronic excitation to the displacements of oxygen atoms.
Ichinomiya, Takashi*; Uberuaga, B. P.*; Sickafus, K. E.*; Nishiura, Yasumasa*; Itakura, Mitsuhiro; Chen, Y.*; Kaneta, Yasunori*; Kinoshita, Motoyasu
Journal of Nuclear Materials, 384(3), p.315 - 321, 2009/02
Times Cited Count：33 Percentile：88.02(Materials Science, Multidisciplinary)We studied the migration dynamics of oxygen point defects in UO which is the primary ceramic fuel for light-water reactors. Temperature accelerated dynamics simulations are performed for several initial conditions. Though the migration of the single interstitial is much slower than that of the vacancy, clustered interstitial shows faster migration than those. This observation gives us important insight on the formation mechanism of high-burnup restructuring, including planar defects and grain sub-division (the rim structure), found in UO.
Ono, Hirotaka*; Iwase, Akihiro*; Matsumura, Daiju; Nishihata, Yasuo; Mizuki, Junichiro; Ishikawa, Norito; Baba, Yuji; Hirao, Norie; Sonoda, Takeshi*; Kinoshita, Motoyasu
Nuclear Instruments and Methods in Physics Research B, 266(12-13), p.3013 - 3017, 2008/06
Times Cited Count：62 Percentile：95.76(Instruments & Instrumentation)Radiation damage of CeO irradiated with 200MeV Xe is characterized by EXAFS and XPS measurement. It is found that oxygen deficiencies are created after the irradiation, and charge state of Ce is changed from +4 to +3.
Sonoda, Takeshi*; Kinoshita, Motoyasu*; Ishikawa, Norito; Sataka, Masao; Chimi, Yasuhiro; Okubo, Nariaki; Iwase, Akihiro*; Yasunaga, Kazufumi*
Nuclear Instruments and Methods in Physics Research B, 266(12-13), p.2882 - 2886, 2008/06
Times Cited Count：33 Percentile：87.03(Instruments & Instrumentation)High-energy particle irradiation effects of CeO is investigated using electron microscopy. It is found that ion track is formed only when the electronic energy transfer exceeds 16 keV/nm.
by using synchrotron radiation X-ray absorption spectroscopy; As a simulation study for radiation damage in high-burnup light water reactor fuelsOno, Hirotaka*; Matsumura, Daiju; Nishihata, Yasuo; Mizuki, Junichiro; Ishikawa, Norito; Sonoda, Takeshi*; Kinoshita, Motoyasu*; Iwase, Akihiro*
Materials Research Society Symposium Proceedings, Vol.1043, p.179 - 183, 2008/00
CeO thin films were irradiated with 200 MeV Xe ions. Effects of the irradiation were studied by using Extended X-ray Absorption Fine Structure (EXAFS) measurement at SPring-8 synchrotron radiation facility. EXAFS spectra for the irradiated thin films near the Ce K-edge show that the coordination number for oxygen atoms around Ce atom decreases and that the Ce-O Debye-Waller factor increases by the irradiation. The atomic distance between oxygen atom and Ce atom does not vary within the accuracy of EXAFS measurement. The effect of high density electronic excitation on the structure of CeO is discussed.
Kinoshita, Motoyasu*; Geng, H. Y.*; Chen, Y.*; Kaneta, Yasunori*; Iwasawa, Misako*; Onuma, Toshiharu*; Sonoda, Takeshi*; Yasunaga, Kazufumi*; Matsumura, Sho*; Yasuda, Kazuhiro*; et al.
Proceedings of 2006 International Meeting on LWR Fuel Performance (TopFuel 2006) (CD-ROM), p.248 - 254, 2006/10
The New Crossover Project (NXO) is studying effect of fission irradiation on fuel material that research activity is crossing over universities, national and private laboratories. Simulation studies are being performed to find principal and triggering processes of the rim-structure formation in high burnup LWR fuel pellet, using accelerator irradiation and computational calculations. Accelerator irradiation, high energy electron irradiation, fission energy particle beam and ion implantation (ragegas atoms) and combined overlapping irradiations are being performed. For the target of irradiation, CeO isused as simulation of nuclear fuel. The initial results were such as planar structure made by Oxygen defects created by high energy electrons, and surface modification similar to grain-sub-division created by high fluence high energy particle irradiations.
Ichikawa, Michio;
Kaku Nenryo Kogaku; Genjo To Tembo, p.392 - 398, 1993/11
no abstracts in English
; Ichikawa, Michio; ; ; ; ; ;
JAERI 1298, 90 Pages, 1985/12
no abstracts in English
; Ichikawa, Michio; ; ; ; ; ;
JAERI-M 9251, 64 Pages, 1981/01
no abstracts in English
Kinoshita, Motoyasu; Yasunaga, Kazufumi*; Sonoda, Takeshi*; Iwase, Akihiro*; Ishikawa, Norito; Sataka, Masao; Yasuda, Kazuhiro*; Matsumura, Sho*; Geng, H. Y.*; Ichinomiya, Takashi*; et al.
no journal, ,
We show the outline of achievements of New Cross Over (NXO) project. Concerning the grain subdivision of ceramics fuel at high burnup, we are trying to clarify the mechanisms and to develop the simulation methods. The main high lights are as follow as: (1) We have reproduced the grain subdivision of CeO, by means of ion implanter and TUNDEM accelerator. (2) We performed computational science study concerning the relocation of oxygen. In case of oxygen exess conditions, first principal calculation reproduced the orderring structure. TAD calculation shows that the exess oxygen compose clusters and diffuses rapidly even if low temperature.
by means of syncrotron radiation X-ray photoelectron spectroscopy and Ce K-edge EXAFS spectroscopyIwase, Akihiro*; Ono, Hirotaka*; Matsumura, Daiju; Nishihata, Yasuo; Mizuki, Junichiro; Ishikawa, Norito; Baba, Yuji; Hirao, Norie; Sonoda, Takeshi*; Kinoshita, Motoyasu*
no journal, ,
To study the effects of swift heavy ion irradiation in cerium dioxide, the samples were irradiated with 200MeV Xe. The irradiated samples were analyzed by EXAFS measurement and XPS measurement.
Kinoshita, Motoyasu; Chen, Y.*; Abe, Hiroaki*; Nishiura, Yasumasa*; Matsumura, Sho*; Iwase, Akihiro*; Sonoda, Takeshi*; Sataka, Masao; Kaburaki, Hideo; Nakamura, Jinichi
no journal, ,
no abstracts in English
Suzudo, Tomoaki; Kaburaki, Hideo; Itakura, Mitsuhiro; Kinoshita, Motoyasu
no journal, ,
The advent of large fission-gas bubbles in the high-burnup fuels limits their life-time and is always accompanied by the grain subdivision. Thus it is surmised that grain sub-division is a key to understand this microstructure change. We in this presentation computationally study the grain sub-division mentioned above, and for this purpose we developed a mesoscale model without recourse to dislocation dynamics that always involve many of daunting tasks. It roughly models the grain subdivision through the dislocation cell formation associated with the rotation of crystallographic orientation. Through the comparison with the experimental observations, we discuss the validity of the model.
; Cub-octahedoral clustersGeng, H. Y.*; Chen, Y.*; Iwasawa, Misako*; Onuma, Toshiharu*; Kinoshita, Motoyasu
no journal, ,
Chen, Y.*; Kaneta, Yasunori*; Geng, H. Y.*; Shang, J. C.*; Iwasawa, Misako*; Onuma, Toshiharu*; Sonoda, Takeshi*; Ichinomiya, Takashi*; Suzudo, Tomoaki; Itakura, Mitsuhiro; et al.
no journal, ,
The outcome of the New Crossover Project Study is outlined. The computational results includes the ab-initio study, molecular dynamics, statistical dynamics/thermal dynamics and meso-scopic modeling, and the experimental results given by an accelerator is also mentioned. Finally, we mention the future plans and the problems.
and UOKaneta, Yasunori*; Geng, H. Y.*; Chen, Y.*; Iwasawa, Misako*; Onuma, Toshiharu*; Kinoshita, Motoyasu
no journal, ,
no abstracts in English
and CeO for clarification of grain sub-division mechanism in high burnup fuelsSonoda, Takeshi*; Ishikawa, Norito; Sataka, Masao; Okubo, Nariaki; Yasunaga, Kazufumi*; Yasuda, Kazuhiro*; Shiiyama, Kenichi*; Matsumura, Sho*; Iwase, Akihiro*; Kinoshita, Motoyasu
no journal, ,
Ion irradiation was performed for CeO and UO. Same kind of microstructure change is observed for both of the oxide materials.
irradiated with swift heavy ionsYasunaga, Kazufumi*; Sonoda, Takeshi*; Yasuda, Kazuhiro*; Shiiyama, Kenichi*; Matsumura, Sho*; Sataka, Masao; Ishikawa, Norito; Chimi, Yasuhiro; Kinoshita, Motoyasu
no journal, ,
In order to study the elementary damage process of high burnup structure of light water reactor, ion implantation and ion irradiation were performed for CeO. It is suggested from the observation of electron microscopy that Xe gas suppress movement of dislocation in CeO.
irradiated with swift heavy ionsIwase, Akihiro*; Ono, Hirotaka*; Ishikawa, Norito; Matsumura, Daiju; Nishihata, Yasuo; Mizuki, Junichiro; Baba, Yuji; Hirao, Norie; Sonoda, Takeshi*; Kinoshita, Motoyasu
no journal, ,
In order to elucidate the mechanism of high burnup structure of light water reactor, high energy ion irradiation (200MeV Xe) was performed. The damage behavior was evaluated with synclotron radiation. It is suggested that charge state of Ce atom changes from +4 to +3 after the irradiation.
in the presence of defects of metal latticeIchinomiya, Takashi*; Nishiura, Yasumasa*; Itakura, Mitsuhiro; Kinoshita, Motoyasu
no journal, ,
The effect of lattice defects in UO such Uranium vacancy and Xe atom on the diffusion of oxygen vacancy has been investigated by temperature accelerated MD simulations. U-vacancy was found to have very low mobility and its migration was very rare. O-vacancy is bound to this U-vacancy with 0.76 eV bounding energy. From these results, we found that O-vacancy diffusion is suppressed by U-vacancy.
