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Kofuji, Hirohide; Fukushima, Mineo; Kitawaki, Shinichi; Myochin, Munetaka; Kormilitsyn, M. V.*; Terai, Takayuki*
IOP Conference Series; Materials Science and Engineering, 9, p.012010_1 - 012010_8, 2010/05
Times Cited Count：0 Percentile：1.02(Chemistry, Inorganic & Nuclear)Nakahara, Masaumi; Nomura, Kazunori; Koizumi, Tsutomu
IOP Conference Series; Materials Science and Engineering, 9, p.012065_1 - 012065_6, 2010/05
Times Cited Count：1 Percentile：54.48(Chemistry, Inorganic & Nuclear)On U crystallization, there is concern that Cs
Pu(NO
)
are deposited on the UNH crystal. Physicochemical properties of CsPu(NO) was studied for its condition of formation and decontamination to U in the crystal. The solubility of CsPu(NO) in HNO solution increased with decreasing the HNO concentration at 25 
C. The thermal analysis showed that CsPu(NO) was stable below 245 C. Since the UNH crystal melts at 60.2 C, CsPu(NO) was attempt to be separated from the UNH crystal due to their different melting points. Although the decontamination factors of Pu and Cs for U melt was about 1 by using a filter of 5.0 
m, it improved to be about 2 with a filter of 0.45 m.
Pu
)O
(1.92
x2.00) based fuels containing actinides and/or lanthanidesKomeno, Akira; Kato, Masato; Uno, Hiroki*; Takeuchi, Kentaro; Morimoto, Kyoichi; Kashimura, Motoaki
IOP Conference Series; Materials Science and Engineering, 9, p.012016_1 - 012016_7, 2010/05
Times Cited Count：8 Percentile：93.82(Chemistry, Inorganic & Nuclear)It is expected that the important data for design of fast reactor fuel can be provided by evaluating the relationship between fuel composition and phase separation with reported and new measurement data. According to evaluation with reported data and new measured data, a relationship between fuel composition and phase separation temperature of MOX fuel was indicated. Higher minor actinides-containing MOX had a lower phase separation temperature at O/M ratio region from 1.92 to 1.96.
AlHaga, Yoshinori; Homma, Yoshiya*; Aoki, Dai*; Ikeda, Shugo*; Matsuda, Tatsuma; Tateiwa, Naoyuki; Yamamoto, Etsuji; Nakamura, Akio; Nakajima, Kenji; Arai, Yasuo; et al.
IOP Conference Series; Materials Science and Engineering, 9, p.012046_1 - 012046_7, 2010/05
Times Cited Count：0 Percentile：1.02(Chemistry, Inorganic & Nuclear)Sato, Isamu; Tanaka, Kosuke; Arima, Tatsumi*
IOP Conference Series; Materials Science and Engineering, 9, p.012005_1 - 012005_8, 2010/05
Times Cited Count：2 Percentile：70.97(Chemistry, Inorganic & Nuclear)UO discs and Am containing MOX discs were prepared to be diffusion couples. They were annealed for 4.5 h at 1600C in a furnace under the constant oxygen partial pressures, and then concentrations of Pu and Am across the interfaces of them were measured with EPMA. The average diffusion coefficients of Pu and Am were obtained from the concentration profiles and were between 10
and 10
m/s
, in which the difference between Pu and Am was undetermined. This indicates that the difference between redistributions of Pu and Am found in a PIE may not be caused by the diffusion but by the other transport phenomenon. Moreover, the diffusion behavior was affected by existence of grain boundaries and the oxygen partial pressure in the furnace during annealing. From the affection of the grain boundary to the diffusion, the "practical" diffusion estimation may need grain boundary modeling.
Miwa, Shuhei; Osaka, Masahiko
IOP Conference Series; Materials Science and Engineering, 9, p.012013_1 - 012013_7, 2010/05
Times Cited Count：1 Percentile：54.48(Chemistry, Inorganic & Nuclear)For the evaluation of chemical behaviors of irradiated fuel and decontaminated fuel, the oxygen potential of (Pu
Am
Nd
)O was experimentally investigated by thermogravimetric analysis with HO/H and CO/H gas equilibrium.
Minato, Kazuo; Konashi, Kenji*; Fujii, Toshiyuki*; Uehara, Akihiro*; Nagasaki, Shinya*; Otori, Norikazu*; Tokunaga, Yo; Kambe, Shinsaku
IOP Conference Series; Materials Science and Engineering, 9, p.012018_1 - 012018_7, 2010/05
Times Cited Count：0 Percentile：1.02(Chemistry, Inorganic & Nuclear)Basic research in actinide chemistry and physics is indispensable to maintain sustainable development of innovative nuclear technology. Actinides, especially minor actinides of americium and curium, need to be handled in special facilities with containment and radiation shields. To promote and facilitate the actinide research, close cooperation with the facilities and sharing of technical and scientific information must be very important and effective. A three-year-program "Basic actinide chemistry and physics research in close cooperation with hot laboratories", ACTILAB, was started to form the bases of sustainable development of innovative nuclear technology. In this program, researches on actinide solid-state physics, solution chemistry and solid-liquid interface chemistry are made using four main facilities in Japan in close cooperation with each other, where basic experiments with transuranium elements can be made. The 
O-NMR measurements were performed on (Pu
Am
)O to study the electronic state and the chemical behaviour of Am and Cm ions in electrolyte solutions was studied by distribution experiments.
Morita, Yasuji; Sasaki, Yuji; Asakura, Toshihide; Kitatsuji, Yoshihiro; Sugo, Yumi; Kimura, Takaumi
IOP Conference Series; Materials Science and Engineering, 9, p.012057_1 - 012057_11, 2010/05
Times Cited Count：7 Percentile：92.11(Chemistry, Inorganic & Nuclear)The authors have developed a new type of extractant for Am and Cm, 
-tetraoctyl-diglycolamide (TODGA), which gives very high distribution ratio at relatively high nitric acid concentration. To apply such a new extractant to the separation process for Am and Cm from HLLW, many criteria should be investigated and satisfied; e.g., separability against fission products (FP), chemical and radiolytic stability, extraction capacity, compatibility with hydrocarbon diluents, and so on. From a viewpoint of extraction capacity, TODGA is modified to -tetradodecyl-diglycolamide (TDdDGA). Since TDdDGA extract Zr and Pd, effective masking agents for them were examined and selected. With those achievements, a counter-current extraction test with 0.1 M TDdDGA in n-dodecane was carried out using a small-scale mixer-settler and simulated solution of HLLW. As results of the test, a very high recovery of Am, more than 99.96%, was obtained and good separation from FP was observed.
Nishi, Tsuyoshi; Takano, Masahide; Ito, Akinori; Miyata, Seiichi; Akabori, Mitsuo; Arai, Yasuo; Minato, Kazuo
IOP Conference Series; Materials Science and Engineering, 9, p.012017_1 - 012017_8, 2010/05
Times Cited Count：2 Percentile：70.97(Chemistry, Inorganic & Nuclear)The thermal diffusivities and heat capacities of transuranium nitride solid solutions, (Np,Am)N and (Pu,Am)N, were measured by using a laser flash method and a drop calorimetry, respectively. The thermal conductivities of these samples were determined from the measured thermal diffusivities, heat capacities and bulk densities. The thermal conductivities of (Np,Am)N and (Pu,Am)N increased with temperature over the temperature range investigated. The increases in the thermal conductivities were probably due to the increase of electrical components. In addition, the thermal conductivities of (Np,Am)N and (Pu,Am)N decreased with increasing Am contents. It could be considered that the decreases in the thermal conductivities correspond to the lowering of electronic contribution.
Kitatsuji, Yoshihiro; Kimura, Takaumi; Kihara, Sorin*
IOP Conference Series; Materials Science and Engineering, 9, p.012078_1 - 012078_7, 2010/05
Times Cited Count：0 Percentile：1.02(Chemistry, Inorganic & Nuclear)The behaviors of reduction of Np(V) by controlled potential electrolysis were studied, and a unique time course of electrolysis current was observed. It was conclude that Np(V) was reduced by two reduction processes that are the chemical reaction with Np(III) and the electrocatalytic reduction by adsorbed hydrogen atom on platinum electrode surface. The time course of current for controlled potential electrolysis of Np(V) under various condition of the solution was investigated, and the effects of the concentration of H
and NO
on electrolysis behaviour were shown.
PuO by EMF methodOtobe, Haruyoshi; Akabori, Mitsuo; Arai, Yasuo
IOP Conference Series; Materials Science and Engineering, 9, p.012015_1 - 012015_7, 2010/05
Times Cited Count：1 Percentile：54.48(Chemistry, Inorganic & Nuclear)The dependence of the oxygen potentials on oxygen nonstoichiometry (
) and temperature of CmPuO was measured by electromotive force (EMF) measurements. The coulomb titration has been made for the sample at the intervals of 40 K between 1173 and 1333 K over the range of 0.018 
0.053. The oxygen potentials decreased gradually from -31.02 to -117.48 kJmol
with increasing from 0.018 to 0.045, and the rapidly decreased from -117.48 to -283.74 kJmol up to 0.053. The temperature dependence of the oxygen potentials was also measured between 1173 and 1333 K for several constant values. The temperature dependence was almost linear over the and temperature ranges concerned.
Metoki, Naoto; Kaneko, Koji; Ikeda, Shugo*; Sakai, Hironori; Yamamoto, Etsuji; Haga, Yoshinori; Homma, Yoshiya*; Shiokawa, Yoshinobu*
IOP Conference Series; Materials Science and Engineering, 9, p.012088_1 - 012088_8, 2010/05
Times Cited Count：1 Percentile：54.48(Chemistry, Inorganic & Nuclear)Inelastic neutron scattering study has been carried out on US. A clear crystalline electric field (CEF) peak has been observed at 7.4 meV, which is consistent with the level scheme obtained from susceptibility data assuming 5f configuration. The CEF becomes very weak and broad, and a quasi-elastic response emerges above the characteristic temperature 
100 K. It indicates the crossover of the 5f character between localized and itinerant. A quasi-elastic response can be concluded as the hybridization effect of the 5f electrons with ligand p-electrons. Our study suggests that the crossover of the 5f character is the origin of the metal-insulator transition in US.
Okude, Genki*; Fujii, Toshiyuki*; Uehara, Akihiro*; Sekimoto, Shun*; Minato, Kazuo; Yamana, Hajimu*
IOP Conference Series; Materials Science and Engineering, 9, p.012067_1 - 012067_7, 2010/05
Times Cited Count：2 Percentile：70.97(Chemistry, Inorganic & Nuclear)
Si-NMR study of magnetic anisotropy and hyperfine interactions in the uranium-based ferromagnet UNiSi
Sakai, Hironori; Baek, S.-H.*; Bauer, E. D.*; Ronning, F.*; Thompson, J. D.*
IOP Conference Series; Materials Science and Engineering, 9, p.012097_1 - 012097_7, 2010/05
Times Cited Count：1 Percentile：54.48(Chemistry, Inorganic & Nuclear)UNiSi orders ferromagnetically below 
= 95 K. This material crystallizes in the orthorhombic CeNiSi-type structure. The uranium atoms form double-layers, which are stacked along the crystallographic 
axis (the longest axis). From magnetization measurements the easy (hard) magnetization axis is the 
axis ( axis). Si-NMR measurements have been performed in the paramagnetic state. In UNiSi, two crystallographic Si sites exist with orthorhombic local symmetry. The Knight shifts on each Si sites have been estimated from these spectra of random and oriented powders. The transferred hyperfine couplings have been also derived. It is found that the transferred hyperfine coupling constants on each Si sites are nearly isotropic, and that their Knight shift anisotropy comes from that of the bulk susceptibility. The nuclear-spin lattice relaxation rate 1/T1 shows temperature-independent behaviour, which indicates the existence of localized 
electrons.
and U
in molten LiCl-RbCl eutecticNagai, Takayuki; Uehara, Akihiro*; Fujii, Toshiyuki*; Sato, Nobuaki*; Yamana, Hajimu*
no journal, ,
The binary alkali chloride mixture with the lowest melting point is the LiCl-RbCl eutectic. If pyro-reprocessing process methods can be operated in this LiCl-RbCl eutectic, it means they could be operated at lower temperature. We have confirmed the possibility of the LiCl-RbCl eutectic by measuring the formal redox potentials of the U/U and U/U couples in molten LiCl-RbCl eutectic. In the present study, electronic absorption spectra of U and U in molten LiCl-RbCl eutectic at various temperatures were measured by the UV/Vis/NIR spectrophotometry and the observed absorption bands were analyzed.
mixed solution using a new on-line chemical apparatusTsukada, Kazuaki; Kasamatsu, Yoshitaka*; Asai, Masato; Toyoshima, Atsushi; Ishii, Yasuo; Li, Z.; Kikuchi, Takahiro; Sato, Tetsuya; Nishinaka, Ichiro; Nagame, Yuichiro; et al.
no journal, ,
Anion-exchange chromatographic behavior of element 105, dubnium (Db), produced in the 
Cm(
F,5n) reaction is investigated together with the homologues Nb and Ta in HF/HNO mixed media using a newly developed on-line experimental system. The result indicates that the adsorption sequence on the anion-exchange resin is Ta 
Nb 
Db, and the fluoride complex formation of Db is expected to be weaker than that of homologues.
Ikeda, Atsushi; Kobayashi, Toru; Shiwaku, Hideaki; Okamoto, Yoshihiro; Suzuki, Shinichi; Yaita, Tsuyoshi; Hennig, C.*
no journal, ,
We have recently develop a new hereto N,O-donor extractant, N-alkyl-N-phenyl-1,10-phenanthlorine-2-carboxamide (PTA), for the lump separation of An from other fission products (FPs) containing lanthanides (Ln). These recent studies have suggested that this hetero-donor ligand possessing both hard O donor- and soft N donor atoms is very effective in the separation of several different An (i.e. U, Np, Pu, Am, and Cm) from Ln. Further development of this extractant, such as improving its separation efficiency, requires the basic understanding of its complexation properties with An and other metals. In the present study, the complexation of An and Ln with N-octyl-N-tolyl-1,10-phenanthroline-2-carboxamide (OcTolPTA) was studied by means of UV-visible and X-ray absorption spectroscopies. The results are discussed from the viewpoint of complexation behavior (i.e. formation constants) and complex structure.
Yaita, Tsuyoshi; Shuh, D.*; Ikeda, Takashi; Kobayashi, Toru; Suzuki, Shinichi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Ikeda, Atsushi; Akutsu, Kazuhiro; Guo, J.*
no journal, ,
no abstracts in English
Suzuki, Shinichi; Yaita, Tsuyoshi; Motokawa, Ryuhei; Koizumi, Satoshi; Okamoto, Yoshihiro; Shiwaku, Hideaki
no journal, ,
no abstracts in English
Fujimori, Shinichi
no journal, ,
Recent remarkable progress in ARPES experiments with high energy soft X-ray synchrotron radiation (SX-ARPES) made it possible to directly observe the bulk electronic structure of strongly correlated materials. We have been performing SX-ARPES experiments using SPring-8 BL23SU to understand their electronic structures. In this talk, I will review our recent SX-ARPES studies on heavy Fermion uranium compounds including uranium based superconductors. The results on the heavy Fermion superconductor UPdAl
and UNiAl will be presented. It was found that quasi-particle bands with strong U5
character form Fermi surface at low temperatures, suggesting that U5 electrons have itinerant nature in these compounds. On the other hand, above the characteristic temperature 
, U5 states are excluded from Fermi surface, and they become more localized states. These results were compared with those calculated by the band structure calculation.
