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Ouchi, Kazuki
Hosha Kagaku, (49), p.3 - 7, 2024/03
I introduce the elucidation of the deposition following the oxidation state of uranium and the electrochemical behavior of uranium(IV) chloride in an ionic liquid-organic mixture, as a basic study of in-solution reactions. In addition, I introduce the development of separation methods for actinides using a microchemical chip and polyacrylamide gel electrophoresis, as an applied study for quantitative analytical methods for small amounts of samples.
Saito, Yuki*; Ishiwata, Tobimaru*; Horiuchi, Misato*; Nishiki, Yuto*; Kikuchi, Ryosuke*; Otake, Tsubasa*; Kawakita, Ryohei; Takayama, Yusuke; Mitsui, Seiichiro; Sato, Tsutomu*
Shigen, Sozai Koenshu (Internet), 11(1), 7 Pages, 2024/03
no abstracts in English
Takamizawa, Hisashi; Hata, Kuniki; Nishiyama, Yutaka; Toyama, Takeshi*; Nagai, Yasuyoshi*
Journal of Nuclear Materials, 556, p.153203_1 - 153203_10, 2021/12
Times Cited Count：3 Percentile：44.61(Materials Science, Multidisciplinary)Solute clusters (SCs) formed in pressurized water reactor surveillance test specimens neutron-irradiated to a fluence of 1 
10
n/cm
were analyzed via atom probe tomography to understand the effect of silicon on solute clustering and irradiation embrittlement of reactor pressure vessel steels. In high-Cu bearing materials, Cu atoms were aggregated at the center of cluster surrounded by the Ni, Mn, and Si atoms like a core-shell structure. In low-Cu bearing materials, Ni, Mn, and Si atoms formed cluster and these solutes were not comprised core-shell structure in SCs. While the number of Cu atoms in clusters was decreased with decreasing nominal Cu content, the number of Si atoms had clearly increased. The cluster radius (
) and number density (
) decreased and increased, respectively, with increasing nominal Si content. The shift in the reference temperature for nil-ductility transition (
RT
) showed a good correlation with the square root of volume fraction (
) multiplied by r (
). This suggested that the dislocation cutting through the particles mechanism dominates the precipitation hardening responsible for irradiation embrittlement. The negative relation between the nominal Si content and RT indicated that increasing of nominal Si content reduces the degree of embrittlement.
Koyanagi, Yoshihiko*; Ueta, Shigeki*; Kawasaki, Takuro; Harjo, S.; Cho, K.*; Yasuda, Hiroyuki*
Materials Science & Engineering A, 773, p.138822_1 - 138822_11, 2020/01
Times Cited Count：3 Percentile：18.61(Nanoscience & Nanotechnology)Suzudo, Tomoaki; Yamaguchi, Masatake; Hasegawa, Akira*
Journal of Nuclear Materials, 467(Part 1), p.418 - 423, 2015/12
Times Cited Count：45 Percentile：96.88(Materials Science, Multidisciplinary)Tungsten is expected to be a promising plasma-facing material for future fusion devices, but radiation-induced precipitation (RIP), which leads the material to hardening, is a concern at their practical use. One of the keys to accurate prediction of the emergence of RIP is migration of solute atoms, rhenium and osmium, that are produced by nuclear transmutation through irradiation. We conduct a series of numerical simulations using an atomic kinetic Monte Carlo method and investigate the migration of these solute atoms in the form of tungsten-rhenium and tungsten-osmium mixed dumbbells, considered to be the most efficient "carriers" of the solute atoms. We find that the low rotation energy barrier of these mixed dumbbells leading to three-dimensional migration greatly influences their diffusivities. The result also suggests that, although these dumbbells have three-dimensional motion, one cannot simply reduce their migration behavior to that of vacancy-like spherical objects.
Tanigawa, Hiroyasu; Sakasegawa, Hideo*; Hashimoto, Naoyuki*; Zinkle, S. J.*; Klueh, R. L.*; Koyama, Akira*
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.33 - 36, 2004/04
Extraction replica samples were prepared from F82H-IEA, F82H HT2, JLF-1 and ORNL9Cr to analyze the precipitate distribution. The samples were examined to obtain precipitate size distribution with TEM and to analyze chemical composition distribution with SEM. Back-scattered electron imaging was found to be the effective way to separate Ta-rich precipitate from other precipitates. Results showed that most of the precipitates were M23C6, and the shape is a round ellipsoid in F82H-IEA and HT2, but was a long ellipsoid in JFL-1 and ORNL9Cr. It was also found that MX precipitates were few and large and contain Ti in F82H-IEA and HT2, but a lot of fine MX precipitates without Ti were observed in JLF-1 and ORNL9Cr.
Tanigawa, Hiroyasu; Sakasegawa, Hideo*; Zinkle, S. J.*; Klueh, R. L.*; Koyama, Akira*
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.30 - 32, 2004/04
Extraction residue was made from several HFIR 11J-irradiated RAFs, and the mass change was measured to investigate the irradiation-enhanced change in precipitation. Two different types of filter with coarse and fine pores were used in order to separate the difference of irradiation effects between larger and smaller precipitates. Unirradiated specimens were examined as well. Results suggest that during irradiation the mass of larger precipitates increased in F82H-IEA, Ni-doped F82H, JLF-1 and ORNL9Cr, fine precipitates disappeared in JLF-1, and fine precipitates increased in Ni-doped F82H.
Tanigawa, Hiroyasu; Sakasegawa, Hideo*; Payzant, E. A.*; Zinkle, S. J.*; Klueh, R. L.*; Koyama, Akira*
Fusion Materials Semiannual Progress Report for the Period Ending (DOE/ER-0313/35), p.37 - 40, 2004/04
XRD analyses were performed on the extraction residue of HFIR 11J-irradiated RAFs to investigate the overall precipitate character. Un-irradiated and aged specimens were examined as well. Results suggested that the distinctive peaks of M23C6 (M; Cr, Fe, W) were observed on all specimens. Peaks possibly related to MX (M;Ta,Ti,V : X ; C, N) were observed on the specimens extracted from un-irradiated JLF-1 and ORNL9Cr, but those peaks were not observed on irradiated specimens.
Hasegawa, Masayuki*; Nagai, Yasuyoshi*; Tang, Z.*; Yubuta, Kunio*; Suzuki, Masahide
JAERI-Tech 2003-015, 137 Pages, 2003/03
JAERI-Tech-2003-015.pdf:9.03MB
no abstracts in English
Owada, Hitoshi*; Mihara, Morihiro; *; *
JNC TN8400 2000-027, 19 Pages, 2000/08
Bactch leaching experiments of granite with the artifitial cement leachate and the leachate of low-alkalinity-cement (LW) were carried out to evaluate the effect of the hiperalkaline plume on the environment of the high-level and TRU radioactive waste repository. Dissolution of Si and Al from feldspar included in the granite and precipitation of C-S-H were confirmed from the results of the leaching experiments with artifitial cement leachate. From this result it was found that the composition of sorrounding rock changed. It also suggested that the retardation factor of migration of radionuclides would change. On the contrary, only decrease of concentrations in Si, Al and Ca in the leachate was observed in the experiment with LW. This result might indicate that C-S-H and/or C-A-S-H precipitated as secondary minerals in the LW case. From these results, it was considered that the hiperalkaline plume from the cementitious leachate might caused the change of disposal conditions such as the change in distribution coefficients of rock by precipitation of the secondary mineral and the increase in hydraulic conductivity by the dissolution of rock. On the other hand, the influences of the LW would be comparatively small, because LW and granite might equilibrate in short time.
Kato, Hiroshige*; Sato, Mitsuyoshi*; Owada, Hitoshi*; Mihara, Morihiro;
JNC TN8430 2000-008, 53 Pages, 2000/05
Cementitious materials will be used in TRU waste disposal repository. In such cases, it is considered that the migration of alkaline leachates from cementitious materials, so called high pH plume, will cause dissolution of rock and precipitation of secondary minerals. In addition, the high pH plume will move along the flow of groundwater, so it is predicted that rock formation and components of high pH groundwater vary with time and space. However, time and spatial dependence of the variations of secondary minerals and groundwater components has not been clarified. In order to acquire the data of variations of secondary minerals and groundwater components, we carried out the rock alteration experiments with column method. The crushed granodiorite was filled into 4 meters length column (
3.7 cm) and artificial cement leachate (pH=13.3; Na=0,1 mol/l, K=0.1 mol/l, Ca=0.002 mol/l) was streamed at flow rates of 0.1 ml/min for 7 months at 80
C. As the result, secondary minerals confirmed on the rock were calcite and C-S-H at upstream of column and C-S-H at mid-downstream. The pH value of the fluid dominated by Na and K did not be decreased by reaction with the rock. In this study, the data relating to the effect of high pH plume on rock over the long term was acquired.
Morikawa, Hiroshi*; Kurata, Hiroki; Fujita, Miya*
Journal of Electron Microscopy, 49(1), p.67 - 72, 2000/04
Times Cited Count：11 Percentile：51.36(Microscopy)no abstracts in English
*; *; *; *; Hasegawa, Makoto; Hirano, Koichiro
JNC TY9400 2000-007, 50 Pages, 2000/03
JNC-TY9400-2000-007.pdf:1.29MB
no abstracts in English
Uwaba, Tomoyuki; Mizuta, Shunji;
JNC TN9400 2000-028, 41 Pages, 2000/03
JNC-TN9400-2000-028.pdf:2.52MB
14Cr-25Ni optimized advanced austenic steels have been developed to improve the swelling resistance of 15Cr-20Ni austenic stainless steels used for FBR fuel cladding. ln this improvement, Ti,Nb,V and P were dissolved into 14Cr-25Ni marix by means of the high-temperature solution treatment to make finely distributed and stabilized precipitates in the operation. Furthermore, at the final stage of cold-working, cold-working level increased and residual stress was reduced. ln this study, as fablicated microstructure observation, solubility of alloying elements and grain size test in the manufacturing process were evaluated. Following results were obtained. (1)Spherical precipitates were observed in the grain. Most of them were identified as conjugated carbo-nitride [Ti,Nb(C,N)] by EDX analysis. (2)The dissolved percentages of Ti and Ni in the matrix were about 70% and 30% respectively. Undissoved Ti and Nb may react with undissolved carbon and precipitate as MC carbides. (3)High-temperature solution treatment is effective for the sufficient solubility of alloying elements, but it is likely to induce very large grains, which is the cause of defective signal in the ultrasonic alloy testing. The results of the grain size test showed that the large grain size is reduced in low Nb (0.1wt%) alloy compared with the standard alloy (0.2wt%Nb), and the effectiveness for the grain size control by reducing the Nb content was confirmed. Also, it was suggested that the intermediate heat treatment and cold work conditions would possibly avoid the occurrence of the large grain at the final heat treatment.
*; *; *; *
JNC TJ8400 2000-061, 92 Pages, 2000/03
JNC-TJ8400-2000-061.pdf:8.79MB
Crystallization procedure is considered to have an advantage in recovering rather pure uranium from contaminated uranium solution and to be applicable for a new reprocessing process. It was confirmed until last year that the reprocessing process with crystallization procedure has a sufficient advantage. But the data for Pu crystallization is very rare. although it is necessary for design of the process with crystallization procedure. In this study, a beaker scale plutonium test was performed in AEA Technology Harwell Laboratory to confirm a behavior of Pu (IV) nitrate under crystallization condition. The results were examined by Mitsubishi Materials Corporation. Test item was a measurement of temperature in case of Pu (IV) nitrate crystallization or freezing of the solution in the following six parameters. (Pu(g/L):200, 100, 50, HNO
(m):6, Pu valence:4). (Pu(g/L):200, 100, 50, HNO(m):4, Pu valence:4). Test results were as follows. (1)Pu(IV) nitrate crystallization was not observed even in the case 200g Pu/L and HNO 6M and 4M which were considered to the best condition but crystal of H
O and HNO 
3HO were observed. (2)Similar results were obtained for the other parameter with lower Pu concentration. (3)We can estimate that Pu(IV) nitrate crystallization will not occurred in the reprocessing process with crystallization procedure. (4)The solubility data of Pu(NO)
- HNO-HO system was obtained.
Kawanishi, Hiroshi*; Suzuki, Masahide
Effects of Radiation on Materials (ASTM STP 1366), p.492 - 515, 2000/03
Times Cited Count：1 Percentile：65.22(Materials Science, Multidisciplinary)no abstracts in English
Wakai, Eiichi; Hishinuma, Akimichi; Miwa, Yukio; Ouchi, Asao*; Isozaki, Seiichi*; Takaki, Seiichi*; Abiko, Kenji*
Materials Transactions, JIM, 41(1), p.136 - 140, 2000/01
no abstracts in English
Niimi, Motoji; Matsui, Yoshinori; Jitsukawa, Shiro; Hoshiya, Taiji; Tsukada, Takashi; Omi, Masao; Mimura, Hideaki; Ooka, Norikazu; *
Journal of Nuclear Materials, 271-272, p.92 - 96, 1999/00
Times Cited Count：5 Percentile：40.62(Materials Science, Multidisciplinary)no abstracts in English
Shirai, Osamu; Iwai, Takashi; Suzuki, Yasufumi; Sakamura, Y.*; *
Journal of Alloys and Compounds, 271-273, p.685 - 688, 1998/00
Times Cited Count：85 Percentile：94.83(Chemistry, Physical)no abstracts in English
Nakajima, Kunihisa; Arai, Yasuo;
Journal of Nuclear Materials, 247, p.33 - 36, 1997/00
Times Cited Count：12 Percentile：67.87(Materials Science, Multidisciplinary)no abstracts in English
