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Ozawa, Takayuki; Hirooka, Shun; Kato, Masato; Novascone, S.*; Medvedev, P.*
Journal of Nuclear Materials, 553, p.153038_1 - 153038_16, 2021/09
Times Cited Count：4 Percentile：56.94(Materials Science, Multidisciplinary)To evaluate the O/M dependence of pore migration regarding fuel restructuring at the beginning of irradiation, we are developing BISON for MOX in cooperation with INL and have installed pore migration model considering vapor pressure of vapor species and thermal conductivity for MOX. The O/M dependence of fuel restructuring observed in MA-bearing MOX irradiation experiment in Joyo was evaluated by the 2-dimensional analyses. Four MA-bearing MOX pins with different O/M ratio and pellet/cladding gap size were irradiated in Joyo B14 experiment. Remarkable restructuring of stoichiometric MA-bearing MOX fuels was observed in PIE, and could be evaluated by considering the influence of O/M ratio on vapor pressure. Also, a central void assumes to move toward wide-gap side when the pellet eccentricity taking place, but 2-dimentional analyses on pellet transverse section revealed that the central void formation observed in PIE would be inconsistent with a direction of the pellet eccentricity.
Ikusawa, Yoshihisa; Maeda, Koji; Kato, Masato; Uno, Masayoshi*
Nuclear Technology, 199(1), p.83 - 95, 2017/07
Times Cited Count：4 Percentile：37.06(Nuclear Science & Technology)Based on thermal computation results obtained using an irradiation behavior analysis code, we have evaluated the effect of O/M ratio on fuel restructuring from the results of PIEs for the B14 irradiation test fuel, which was a mixed oxide fuel and was irradiated in the experimental reactor Joyo. The thermal computation results showed that fuel restructuring in the stoichiometric oxide fuel was accelerated, though the fuel temperature in the stoichiometric oxide fuel was evaluated as lower than that of the hypo-stoichiometric one. We explained this behavior as follows: first, the fuel temperature decreased due to the high thermal conductivity at stoichiometry; second, the pore migration velocity increased due to the increase in vapor pressure caused by the high vapor pressure of UO
, which was derived from the high oxygen potential at stoichiometry. In addition, our results indicated that the central void diameter strongly depended on not only fuel temperature, but also vapor pressure.
Ozawa, Takayuki; Ikusawa, Yoshihisa; Kato, Masato
Transactions of the American Nuclear Society, 113(1), p.622 - 624, 2015/10
A recycle system for minor actinides (MAs), in which MAs are recycled by reprocessing and irradiating them in a fast reactor, is studied to reduce the degree of hazard and the amount of high-level radioactive wastes. MAs would be used as mixed oxide (MOX) fuels with plutonium and uranium in fast reactors. Since MA content of MA-bearing MOX (MA-MOX) to be used in fast reactors is assumed to reach 
5 wt%HM, the effects on not only fuel properties but also fuel behaviors have to be estimated to use MA-MOX as fast reactor fuels. As the MOX fuels to be used will be irradiated at a comparably high linear power and the fuel center temperature would be assumed to be over 2,273 K during irradiation in the fast reactors, fuel restructuring would take place due to void migration towards the fuel center under the radial temperature gradient, and a central void would be formed. Since the fuel center temperature would be decreased by the effect of formation of the central void, the fuel restructuring is one of the most important behaviors for fast reactor fuels. In this study, the effect of MA content on fuel restructuring behavior was estimated from the results of irradiation experiments such as B11 and B14 performed in Joyo to study the irradiation behaviors of MA-MOX and the calculation results using a fuel restructuring model which can take into account MA-MOX dependence on vapor pressure.
Harada, Yuhei; Maruyama, Yu; Maeda, Akio; Shibazaki, Hiroaki*; Kudo, Tamotsu; Hidaka, Akihide; Hashimoto, Kazuichiro; Sugimoto, Jun
Journal of Nuclear Science and Technology, 36(10), p.923 - 933, 1999/10
Times Cited Count：3 Percentile：28.69(Nuclear Science & Technology)no abstracts in English
Sawai, Tomotsugu; Shiba, Kiyoyuki; Hishinuma, Akimichi
Journal of Nuclear Materials, 258-263, p.1997 - 2001, 1998/00
Times Cited Count：3 Percentile：31.85(Materials Science, Multidisciplinary)no abstracts in English
Arai, Yasuo; Iwai, Takashi; ; Okamoto, Yoshihiro; Nakajima, Kunihisa; Niimi, Motoji; ; Yamahara, Takeshi;
JAERI-Research 95-008, 92 Pages, 1995/02
JAERI-Research-95-008.pdf:5.04MB
no abstracts in English
; ; ; *
Journal of Nuclear Science and Technology, 24(6), p.480 - 489, 1987/06
Times Cited Count：2 Percentile：29.78(Nuclear Science & Technology)no abstracts in English
; Katano, Y.; Shiraishi, K.
Journal of Nuclear Science and Technology, 21(9), p.671 - 677, 1984/00
Times Cited Count：14 Percentile：79.2(Nuclear Science & Technology)no abstracts in English
Ikusawa, Yoshihisa; Ozawa, Takayuki; Kato, Masato; Uno, Masayoshi*
no journal, ,
We studied the vapor pressure model of Am-MOX fuel and evaluated the effect of a change in the Am content on fuel restructuring in fast reactor oxide fuel. An increase in the Am content decreases the thermal conductivity and increases the oxygen potential in oxide fuel. Since the vapor pressure increases with the increase in the Am content by these effects, it is understood that the void migration is accelerated and the fuel restructuring easily occur in Am-MOX fuel rather than in conventional MOX fuel.
Ozawa, Takayuki; Hirooka, Shun; Kato, Masato; Novascone, S.*; Medvedev, P.*
no journal, ,
To evaluate the O/M dependence of pore migration regarding fuel restructuring at the beginning of irradiation, we are developing BISON for MOX in cooperation with INL and have installed pore migration model considering vapor pressure of vapor species and thermal conductivity for MOX. The O/M dependence of fuel restructuring observed in MA-bearing MOX irradiation experiment in Joyo was evaluated by the 2-dimensional analyses. Four MA-bearing MOX pins with different O/M ratio and pellet/cladding gap size were irradiated in Joyo B14 experiment. Remarkable restructuring of stoichiometric MA-bearing MOX fuels was observed in PIE, and could be evaluated by considering the influence of O/M ratio on vapor pressure. Also, a central void assumes to move toward wide-gap side when the pellet eccentricity taking place, but 2-dimentional analyses on pellet transverse section revealed that the central void formation observed in PIE would be inconsistent with a direction of the pellet eccentricity.
