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Tanaka, Kazuya; Yamaji, Keiko*; Masuya, Hayato*; Tomita, Jumpei; Ozawa, Mayumi*; Yamasaki, Shinya*; Tokunaga, Kohei; Fukuyama, Kenjin*; Ohara, Yoshiyuki*; Maamoun, I.*; et al.
Chemosphere, 355, p.141837_1 - 141837_11, 2024/05
In this study, biogenic Mn(IV) oxide was applied to remove Ra from mine water collected from a U mill tailings pond in the Ningyo-toge center. Just 7.6 mg of biogenic Mn(IV) oxide removed more than 98% of the 
Ra from 3 L of mine water, corresponding to a distribution coefficient of 10
mL/g for Ra at pH 7. The obtained value was convincingly high for practical application of biogenic Mn(IV) oxide in water treatment.
-type layered manganese dioxideOkamoto, Norihiko*; Yoshisako, Hiroki*; Ichitsubo, Tetsu
Energy Storage Materials, 61, p.102912_1 - 102912_9, 2023/08
Times Cited Count：1 Percentile：52.07(Chemistry, Physical)
-edge X-ray absorption fine structure study of 
-type 
CuO
( = Rare Earth); Toward unified understanding of electronic state of -type cuprateChen, Y.*; Asano, Shun*; Wang, T.*; Xie, P.*; Kitayama, Shinnosuke*; Ishii, Kenji*; Matsumura, Daiju; Tsuji, Takuya; Taniguchi, Takanori*; Fujita, Masaki*
JPS Conference Proceedings (Internet), 38, p.011050_1 - 011050_6, 2023/05
frameworksShimokawa, Kohei*; Hatakeyama, Takuya*; Li, H.*; Ichitsubo, Tetsu
Current Opinion in Electrochemistry, 38, p.101209_1 - 101209_8, 2023/04
Times Cited Count：1 Percentile：35.25(Chemistry, Physical)Kumagai, Yuta
Hoshasen Kagaku (Internet), (115), p.43 - 49, 2023/04
Oxidation and dissolution of uranium oxide materials has been a subject of numerous studies as a basis of the geological disposal technology for spent nuclear fuel. The understandings obtained by these studies provide useful suggestions for research and development regarding the retrieval and storage of nuclear fuel debris generated by a nuclear severe accident. Here, these research backgrounds of oxidative dissolution of uranium oxides are briefly reviewed and some studies relating to radiation-induced reactions will be introduced.
Otsuka, Satoshi; Shizukawa, Yuta; Tanno, Takashi; Imagawa, Yuya; Hashidate, Ryuta; Yano, Yasuhide; Onizawa, Takashi; Kaito, Takeji; Onuma, Masato*; Mitsuhara, Masatoshi*; et al.
Journal of Nuclear Science and Technology, 60(3), p.288 - 298, 2023/03
Times Cited Count：4 Percentile：78.52(Nuclear Science & Technology)JAEA has been developing 9Cr-oxide dispersion strengthened (ODS) tempered martensitic steel(TMS) as a candidate material for the fuel cladding tubes of sodium-cooled fast reactors(SFRs). The reliable prediction of in-reactor creep-rupture strength is critical for implementing the 9Cr-ODS TMS cladding tube in the SFR. This study investigated the quantitative correlation between the creep properties of 9Cr-ODS TMS at 700 
C and the dispersions of nanosized oxides by analyzing the creep data and the material's nanostructure. The possibility of deriving a formula for estimating the in-reactor creep properties of 9Cr-ODS TMSs based on an analysis of the nanostructure of neutron-irradiated 9Cr-ODS TMSs was also discussed. The creep properties of 9Cr-ODS TMS at 700 C closely correlated with the dispersion of nanosized oxide particles. The correlation between creep-rupture lives and nanosized oxide particle dispersion was determined using existing creep models. The elucidation of correlation between the stress exponent of secondary creep rate and the nanostructure is essential to enhance future modeling reliability and formulation.
Nuclear Science and Engineering Center; Fuel Cycle Design Office; Plutonium Fuel Development Center; Nuclear Plant Innovation Promotion Office; Fast Reactor Cycle System Research and Development Center; J-PARC Center
JAEA-Review 2022-052, 342 Pages, 2023/02
JAEA-Review-2022-052.pdf:18.05MB
This report summarizes the current status and future plans of research and development (R&D) on partitioning and transmutation technology in Japan Atomic Energy Agency, focusing on the results during the 3rd Medium- to Long-term Plan period (FY 2015-2021). Regarding the partitioning technology, R&D of the solvent extraction method and the extraction chromatography method are described, and regarding the minor actinide containing fuel technology, R&D of the oxide fuel production using the simplified pellet method, the nitride fuel production using the external gelation method, and pyrochemical reprocessing of the nitride fuel were summarized. Regarding transmutation technology, R&D of technology using fast reactors and accelerator drive systems were summarized. Finally, the new facilities necessary for the future R&D were mentioned.
Oka, Hiroshi*; Tanno, Takashi; Yano, Yasuhide; Otsuka, Satoshi; Kaito, Takeji; Hashimoto, Naoyuki*
Journal of Nuclear Materials, 572, p.154032_1 - 154032_8, 2022/12
Times Cited Count：3 Percentile：68.71(Materials Science, Multidisciplinary)9Cr oxide dispersion strengthened steels with slightly different nitrogen concentrations (0.0034 - 0.029 wt%) were prepared and their creep property at 973 K was investigated with microstructural characterization before and after the creep test. The creep strength decreased significantly as the nitrogen concentration increased. Microstructural observation revealed that, in the higher nitrogen concentration specimen, coarse Y-rich inclusions were found along the boundary between transformed ferrite region and residual ferrite region. The solubility difference of nitrogen in 
and 
phase would induce the localized increment of nitrogen concentration in the boundary region during the austenitizing process, resulting in the thermodynamic destabilization and subsequent coarsening of the dispersed oxide particles. The rows of creep voids were found near the rupture part of the crept specimen, suggesting that the coarse inclusions were the starting point of creep void formation and the subsequent premature fracture.
Kobayashi, Taishi*; Fushimi, Tomokazu*; Mizukoshi, Hirofumi*; Motokawa, Ryuhei; Sasaki, Takayuki*
Langmuir, 38(48), p.14656 - 14665, 2022/12
Times Cited Count：2 Percentile：29.84(Chemistry, Multidisciplinary)no abstracts in English
(001) surface with supersonic seeded oxygen molecular beamKatsube, Daiki*; Ono, Shinya*; Inami, Eiichi*; Yoshigoe, Akitaka; Abe, Masayuki*
Vacuum and Surface Science, 65(11), p.526 - 530, 2022/11
The oxidation of oxygen vacancies at the surface of anatase TiO (001) was investigated by synchrotron radiation photoelectron spectroscopy and supersonic O beam (SSMB). The oxygen vacancies at the top surface and subsurface could be eliminated by the supply of hyperthermal oxygen molecules. Oxygen vacancies are present on the surface of anatase TiO(001) when it is untreated before transfer to a vacuum chamber. These vacancies, which are stable in the ambient condition, could also be effectively eliminated by using oxygen SSMB. This result is promising as a surface processing for various functional oxides.
O solutionKumagai, Yuta; Kusaka, Ryoji; Nakada, Masami; Watanabe, Masayuki; Akiyama, Daisuke*; Kirishima, Akira*; Sato, Nobuaki*; Sasaki, Takayuki*
Journal of Nuclear Science and Technology, 59(8), p.961 - 971, 2022/08
Times Cited Count：2 Percentile：53.91(Nuclear Science & Technology)We investigated potential degradation of fuel debris caused by HO, which is the oxidant of major impact from water radiolysis. We performed leaching experiments on different kinds of simulated debris comprising U, Fe, Cr, Ni, and Zr in an aqueous HO solution. Chemical analysis of the leaching solution showed that U dissolution was induced by HO. Raman analysis after the leaching revealed that uranyl peroxides were formed on the surface of the simulated debris. These results demonstrate that uranyl peroxides are possible alteration products of fuel debris from HO reaction. However, the sample in which the main uranium-containing phase was a U-Zr oxide solid solution showed much less uranium dissolution and no Raman signal of uranyl peroxides. Comparison of these results indicates that formation of an oxide solid solution of Zr with UO improves the stability of fuel debris against HO reaction.
)O
( = Th, Np) prepared by supercritical hydrothermal synthesisShirasaki, Kenji*; Tabata, Chihiro*; Sunaga, Ayaki*; Sakai, Hironori; Li, D.*; Konaka, Mariko*; Yamamura, Tomoo*
Journal of Nuclear Materials, 563, p.153608_1 - 153608_11, 2022/05
Times Cited Count：2 Percentile：53.91(Materials Science, Multidisciplinary)We focused on the direct synthesis of (U, )O solid solution (=Th, Np) by extending our recent progress in hydrothermal synthesis with additives. The homogeneity of the (U, )O ( = Th, Np) systems prepared by supercritical hydrothermal reactions was investigated through crystallographic analysis based on Vegard's law, and the 
Na nuclear magnetic resonance (NMR) measurement of (U, Np, Na)O solid solutions. Our experimental and analytical results revealed that (i) an optimal additive is ammonium carbonate and starting uranium valence is IV in the case of (U, Th)O
, and (ii) an optimal additive is ethanol and starting uranium valence is VI in the case of (U, Np)O, for producing the homogeneous solid solutions by hydrothermal synthesis.
; Stoichiometry, crystal shape and size, and homogeneity observed using Na-NMR spectroscopy of (U, Na)OTabata, Chihiro*; Shirasaki, Kenji*; Sunaga, Ayaki*; Sakai, Hironori; Li, D.*; Konaka, Mariko*; Yamamura, Tomoo*
CrystEngComm (Internet), 23(48), p.8660 - 8672, 2021/12
Times Cited Count：5 Percentile：64.74(Chemistry, Multidisciplinary)The hydrothermal synthesis of pure uranium dioxide under supercritical water (SCW) conditions was investigated. The nonstoichiometry, crystallite size and morphology of the UO particles were investigated. The SCW hydrothermal synthesis may be a promising method for producing homogeneous UO and its solid solutions with well-defined nonstoichiometries (
), shapes, and sizes.
Ln
O
(Ln = Gd, Er) solid solutionPham, V. M.*; Arima, Tatsumi*; Inagaki, Yaohiro*; Idemitsu, Kazuya*; Akiyama, Daisuke*; Nagai, Takayuki; Okamoto, Yoshihiro
Journal of Nuclear Materials, 556, p.153189_1 - 153189_9, 2021/12
Times Cited Count：1 Percentile：16.35(Materials Science, Multidisciplinary)The crystal structure change was evaluated for (1-x)UO-xLnO
(Ln=Gd or Er; x = 0 to 0.4) samples sintered at 1973 K for 8 h under Ar and Ar-10%H atmospheres. The effect of LnO doping on the crystal structure of UO was investigated by X-ray diffraction (XRD) and X-ray absorption fine structure (XAFS). LnO doping into UO reduced the lattice parameter of UO-LnO solid solutions up to 40mol% LnO. The lattice parameters of these samples were comparable to those of stoichiometric (U,Ln)O
solid solutions, that is, the O/M ratios were close to 2.00. The U L
-edge XANES analysis showed that higher U oxidation states of +5 or +6 formed, in addition to + 4. The EXAFS analysis indicated that the interatomic distances of U-O and Gd-O decreased with increasing x, whereas those of Er-O may not decrease monotonically.
-type La
Eu
CuO
and NdCuOAsano, Shun*; Ishii, Kenji*; Matsumura, Daiju; Tsuji, Takuya; Kudo, Kota*; Taniguchi, Takanori*; Saito, Shin*; Sunohara, Toshiki*; Kawamata, Takayuki*; Koike, Yoji*; et al.
Physical Review B, 104(21), p.214504_1 - 214504_7, 2021/12
Times Cited Count：0 Percentile：0(Materials Science, Multidisciplinary)Hata, Kuniki
Zairyo To Kankyo, 70(12), p.468 - 473, 2021/12
In order to estimate corrosive environment in the contaminated water at Fukushima Daiichi Nuclear Power Station, effects of oxidants, such as HO, which were generated from water radiolysis, should be taken into account due to the irradiation field in the reactor building. The process of water radiolysis and the amounts of these oxidants can change depending on the conditions of water and types of radiation. After the accident, a variety of factors, which can affect water radiolysis, such as seawater constituents, surface of oxides, and -radionuclides, had been discussed. In this paper, these effects on radiolysis are reviewed for the better understanding of the corrosive environment in the contaminated water.
through irreversible biogenic manganese oxide sequestrationTani, Yukinori*; Kakinuma, Satomi*; Chang, J.*; Tanaka, Kazuya; Miyata, Naoyuki*
Minerals (Internet), 11(1), p.53_1 - 53_14, 2021/01
Times Cited Count：4 Percentile：45.1(Geochemistry & Geophysics)In this study, we examined the Ba sequestration potential of enzymatically active biogenic Mn oxides (BMOs) with and without exogenous Mn. The BMOs readily oxidized exogenous Mn to produce another BMO phase, and subsequently sequestered Ba at a pH of 7.0, with irreversible Ba sequestration as the dominant pathway. Extended X-ray absorption fine structure spectroscopy and X-ray diffraction analyses demonstrated alteration from turbostratic to tightly stacked birnessite through possible Ba incorporation into the interlayer.
particles triggered strong interaction with LaFeO framework for total and preferential CO oxidationZheng, Y.*; Xiao, H.*; Li, K.*; Wang, Y.*; Li, Y.*; Wei, Y.*; Zhu, X.*; Li, H.-W.*; Matsumura, Daiju; Guo, B.*; et al.
ACS Applied Materials & Interfaces, 12(37), p.42274 - 42284, 2020/09
Times Cited Count：22 Percentile：73.67(Nanoscience & Nanotechnology)Segawa, Tomoomi; Kawaguchi, Koichi; Ishii, Katsunori; Suzuki, Masahiro; Fukasawa, Tomonori*; Fukui, Kunihiro*
Funtai Kogakkai-Shi, 57(9), p.485 - 494, 2020/09
In the spent fuel reprocessing process, a mixed solution of uranyl nitrate and plutonium nitrate is converted into mixed oxide powder by the microwave heating. To evaluate the applicability to the industrial-scale and acquire the characteristics data of the microwave heating denitration of various metal nitrate aqueous solutions based on the knowledge studied in the development of laboratory-scale basic experiments, the microwave heating characteristics and metal oxide powder properties were investigated using cerium nitrate, cobalt nitrate and copper nitrate aqueous solutions. The progress rate of the denitration reaction was depended on the position, and the denitration reaction proceeded faster at the periphery than at the center. The morphologies of the synthesized products were porous and hard dry solid with cerium nitrate aqueous solution, foamed dry solid with cobalt nitrate aqueous solution, and powdery particles with copper nitrate aqueous solution. The denitration ratio and average particle size of the synthesized products increased in the order of the cerium nitrate aqueous solution, the cobalt nitrate aqueous solution, and the copper nitrate aqueous solution. The numerical simulations revealed that the periphery of the bottom surface of the metal nitrate aqueous solution was heated by microwaves. This results consistent with the experimental results in which the denitration reaction started from the periphery of the metal nitrate aqueous solution.
Ukai, Shigeharu*; Ono, Naoko*; Otsuka, Satoshi
Comprehensive Nuclear Materials, 2nd Edition, Vol.3, p.255 - 292, 2020/08
Fe-Cr-based oxide dispersion strengthened (ODS) steels have a strong potential for high burnup (long-life) and high-temperature applications typical for SFR fuel cladding. Current progress in the development of Fe-Cr-based ODS steel claddings is reviewed, including their relevant mechanical properties, e.g. tensile and creep rupture strengths in the hoop directions. In addition, this paper reviewed the current research status on corrosion resistant Fe-Cr-Al-based ODS steel claddings, which are greatly paid attention recently as the accident tolerant fuel claddings for the light water reactor (LWR) and also as the claddings of the lead fast reactors (LFR) utilizing Pb-Bi eutectic (LBE) coolant.
