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Sakaguchi, Yoshifumi*; Takata, Shinichi; Kawakita, Yukinobu; Fujimura, Yuki; Kondo, Keietsu
Journal of Physics; Condensed Matter, 35(41), p.415403_1 - 415403_11, 2023/10
Times Cited Count：0 Percentile：0(Physics, Condensed Matter)
observation of deformation behavior in high entropy alloys using neutron diffractionHarjo, S.
Nihon Kessho Gakkai-Shi, 65(3), p.178 - 182, 2023/08
, Zr, and stainless-steelKirishima, Akira*; Akiyama, Daisuke*; Kumagai, Yuta; Kusaka, Ryoji; Nakada, Masami; Watanabe, Masayuki; Sasaki, Takayuki*; Sato, Nobuaki*
Journal of Nuclear Materials, 567, p.153842_1 - 153842_15, 2022/08
Times Cited Count：5 Percentile：76.47(Materials Science, Multidisciplinary)To understand the chemical structure and stability of nuclear fuel debris consisting of UO, Zr, and Stainless Steel (SUS) generated by the Fukushima Daiichi Nuclear Power Plant accident in Japan in 2011, simulated debris of the UO-SUS-Zr system and other fundamental component systems were synthesized and characterized. The simulated debris were synthesized by heat treatment for 1 to 12 h at 1600
C, in inert (Ar) or oxidative (Ar + 2% O) atmospheres. 
Np and 
Am tracers were doped for the leaching tests of these elements and U from the simulated debris. The characterization of the simulated debris was conducted by XRD, SEM-EDX, Raman spectroscopy, and M
ssbauer spectroscopy, which provided the major uranium phase of the UO -SUS-Zr debris was the solid solution of U
O (s.s.) with Zr(IV) and Fe(II) regardless of the treatment atmosphere. The long-term immersion test of the simulated debris in pure water and that in seawater revealed the macro scale crystal structure of the simulated debris was chemically very stable in the wet condition for a year or more. Furthermore, the leaching test results showed that the actinide leaching ratios of U, Np, Am from the UO-SUS-Zr debris were very limited and less than 0.08 % for all the experiments in this study.
Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2022-009, 73 Pages, 2022/06
JAEA-Review-2022-009.pdf:2.08MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2020. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Basic research on the stability of fuel debris including alloy phase" conducted from FY2018 to FY2021 (this contract was extended to FY2021). Since the final year of this proposal was FY2021, the results for four fiscal years were summarized. The present study focus on fuel debris consisting of oxide phase and alloy phase generated by the high temperature chemical reaction between structure materials (SUS pipes, pressure vessels, etc.) and fuels (melted fuels, claddings components, etc.). We synthesize the simulated debris of UO-SUS system and UO-Zr(ZrO)-SUS system by high-temperature heat treatment, and measure their chemical property and dissolution behavior in water.
Kakiuchi, Kazuo; Amaya, Masaki; Udagawa, Yutaka
Annals of Nuclear Energy, 171, p.109004_1 - 109004_9, 2022/06
Times Cited Count：4 Percentile：76.47(Nuclear Science & Technology)Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2020-032, 97 Pages, 2021/01
JAEA-Review-2020-032.pdf:4.16MB
The Collaborative Laboratories for Advanced Decommissioning Science (CLADS), Japan Atomic Energy Agency (JAEA), had been conducting the Nuclear Energy Science & Technology and Human Resource Development Project (hereafter referred to "the Project") in FY2019. The Project aims to contribute to solving problems in the nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. (TEPCO). For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Basic Research on the Stability of Fuel Debris Including Alloy Phase" conducted in FY2019. In the present study, we focus on fuel debris consisting of oxide phase and alloy phase generated by the high-temperature chemical reaction between structure materials (SUS pipes, pressure vessels, etc.) and fuels (melted fuels, claddings components, etc.). We synthesize the simulated debris of UO-SUS system and UO-Zr(ZrO)-SUS system by high-temperature heat treatment, and measure their chemical property and dissolution behavior in water. Also, we will conduct research and development to spectroscopically analyze secular changes of oxide phase and alloy phase in the simulated debris.
Collaborative Laboratories for Advanced Decommissioning Science; Tohoku University*
JAEA-Review 2019-035, 61 Pages, 2020/03
JAEA-Review-2019-035.pdf:2.9MB
JAEA/CLADS, had been conducting the Center of World Intelligence Project for Nuclear Science/Technology and Human Resource Development (hereafter referred to "the Project") in FY2018. The Project aims to contribute to solving problems in nuclear energy field represented by the decommissioning of the Fukushima Daiichi Nuclear Power Station, Tokyo Electric Power Company Holdings, Inc. For this purpose, intelligence was collected from all over the world, and basic research and human resource development were promoted by closely integrating/collaborating knowledge and experiences in various fields beyond the barrier of conventional organizations and research fields. The sponsor of the Project was moved from the Ministry of Education, Culture, Sports, Science and Technology to JAEA since the newly adopted proposals in FY2018. On this occasion, JAEA constructed a new research system where JAEA-academia collaboration is reinforced and medium-to-long term research/development and human resource development contributing to the decommissioning are stably and consecutively implemented. Among the adopted proposals in FY2018, this report summarizes the research results of the "Basic Research on the Stability of Fuel Debris Including Alloy Phase". In the present study, we focus on fuel debris consisting of oxide phase and alloy phase generated by the high-temperature chemical reaction between structure materials (SUS pipes, pressure vessels, etc.) and fuels (melted fuels, claddings components, etc.). We synthesize the simulated debris of UO-SUS system and UO-Zr(ZrO)-SUS system by high-temperature heat treatment, and measure their chemical property and dissolution behavior in water. Also, we will conduct research and development to spectroscopically analyze secular changes of oxide phase and alloy phase in the simulated debris.
Naeem, M.*; He, H.*; Zhang, F.*; Huang, H.*; Harjo, S.; Kawasaki, Takuro; Wang, B.*; Lan, S.*; Wu, Z.*; Wang, F.*; et al.
Science Advances (Internet), 6(13), p.eaax4002_1 - eaax4002_8, 2020/03
Times Cited Count：147 Percentile：99.05(Multidisciplinary Sciences)Watanabe, Masashi*; Yonezawa, Toshio*; Shobu, Takahisa; Shiro, Ayumi; Shoji, Tetsuo*
Corrosion, 72(9), p.1155 - 1169, 2016/09
Times Cited Count：1 Percentile：6.22(Materials Science, Multidisciplinary)Yamakawa, Koji*; Chimi, Yasuhiro; Ishikawa, Norito; Iwase, Akihiro*
Journal of Alloys and Compounds, 370(1-2), p.211 - 216, 2004/05
Times Cited Count：1 Percentile：12.41(Chemistry, Physical)The migration of hydrogen in Pd-1at.% Fe-H and Pd-1at.% Ag-H alloys is investigated by electrical resistivity measurement around 50 K. The disordered hydrogen atoms are introduced by electron irradiation with 0.5 MeV electrons below 15 K. The disordered atoms order by migration of hydrogen atoms during the heating-up of the specimens. The recovery curves of electrical resistivity have two sub-stages for electron irradiated specimens and one stage for fast cooled specimens. The migration energy of hydrogen is obtained from the kinetic analysis of the resistivity change due to the ordering, using the cross-cut method for the electron irradiated specimen and fast cooled specimen. The obtained value of the migration energy for the low temperature stage is smaller than that for the high temperature stage. The value for the high temperature stage is similar to the energy for the case of fast cooling. The difference between the hydrogen atoms disordered by irradiation and that by fast cooling is discussed for Pd based alloys.
Nemoto, Yoshiyuki; Hasegawa, Akira*; Sato, Manabu*; Abe, Katsunori*; Hiraoka, Yutaka*
Journal of Nuclear Materials, 324(1), p.62 - 70, 2004/01
Times Cited Count：38 Percentile：90.02(Materials Science, Multidisciplinary)In this study, stress-relieved specimens and recrystallized specimens of pure Mo and Mo-Re alloys (Re content=2,4,5,10,13 and 41wt%) were neutron irradiated up to 20dpa at various temperatures (681-1072K). On microstructure observation, sigma phase and chi phase precipitates were observed in all irradiated Mo-Re alloys. Voids were observed in all irradiated specimen, and dislocation loops and dislocations were observed in the specimens that were irradiated at lower temperatures. On Vickers hardness testing, all of the irradiated specimens showed hardening. Especially Mo-41Re were drastically embrittled after irradiation at 874K or less. From these results, authors discuss about relation between microstructure development and radiation hardening, embrittlement, and propose the most efficient Re content and thermal treatment for Mo-Re alloys to be used under irradiation condition.
Iwase, Akihiro; Hasegawa, Tadayuki*; Chimi, Yasuhiro; Tobita, Toru; Ishikawa, Norito; Suzuki, Masahide; Kambara, Tadashi*; Ishino, Shiori*
Nuclear Instruments and Methods in Physics Research B, 195(3-4), p.309 - 314, 2002/10
Times Cited Count：12 Percentile：60.73(Instruments & Instrumentation)no abstracts in English
Morita, Kenji*; Ishino, Shiori*; Tobita, Toru; Chimi, Yasuhiro; Ishikawa, Norito; Iwase, Akihiro
Journal of Nuclear Materials, 304(2-3), p.153 - 160, 2002/08
Times Cited Count：13 Percentile：63.33(Materials Science, Multidisciplinary)To study the mechanism of irradiation embrittlement in pressure vessel alloys, we performed high energy ion irradiation experiments using FeCu model alloys. The dependences of Vickers hardness change by irradiation on ion fluence, irradiation temperature and Cu content were discussed.
Sn (
=Ti, Zr, and Nb)Yamasaki, Atsushi*; Imada, Shin*; Arai, Ryuji*; Utsunomiya, Hiroshi*; Suga, Shigemasa*; Muro, Takayuki*; Saito, Yuji; Kanomata, Takeshi*; Ishida, Shoji*
Physical Review B, 65(10), p.104410_1 - 104410_6, 2002/03
Times Cited Count：60 Percentile：89.21(Materials Science, Multidisciplinary)The magnetic circular dichroism (MCD) of core-level absorption [x-ray absorption spectroscopy (XAS)] spectra in the soft x-ray region has been measured for the ferromagnetic Heusler alloys CoTiSn, CoZrSn, and CoNbSn. The many-peak structures which are clearly observed in the Co 2p-3d XAS-MCD spectra cannot be well explained by atomic multiplet calculations but are better explained by the Co 3d unoccupied states predicted by linear muffin-tin orbital atomic sphere approximation band structure calculations. The MCD spectra show an obvious contribution of the orbital angular momentum component to the magnetic moment in these alloys. The ratio between the orbital angular momentum and spin derived from the MCD spectra varies by more than a factor of 2 within these alloys. The mechanism of this variation is discussed in comparison with the band structure calculations.
Kurata, Yuji; Saito, T.*; Tsuji, Hirokazu; Takatsu, T.*; Shindo, Masami; Nakajima, Hajime
JSME International Journal, Series A, 45(1), p.104 - 109, 2002/01
no abstracts in English
Kurata, Yuji; Saito, T.*; Tsuji, Hirokazu; Takatsu, T.*; Shindo, Masami; Nakajima, Hajime
Proceedings of the 7th International Conference on Creep and Fatigue at Elevated Temperatures (CREEP7), p.93 - 99, 2001/06
no abstracts in English
Nakata, Yoshiyuki*; Hara, Naoyuki*; Hirotsu, Yoshihiko*; Emura, Shuichi*; Makino, Akihiro*; Uruga, Tomoya*; Harada, Makoto*; Nishihata, Yasuo; Yoneda, Yasuhiro; Kubozono, Yoshihiro*
Japanese Journal of Applied Physics, 38(Suppl.38-1), p.404 - 407, 1999/06
The EXAFS spectra on Zr K-edge are investigated for as-formed Fe-7at%Zr-3at%B amorphous alloys and annealed ones at 693 K and 773 K for an hour in order to reveal local structural changes due to annealing. The analysis shows that the atomic distances of Fe-Zr and Zr-Zr pairs increase during annealing and approach those in a Fe3Zr or/and Fe2Zr metallic comound. The change in the atomic distances suggests that medium range ordered clusters should be formed during annealing.
Ogawa, Toru; Okamoto, Yoshihiro; R.J.K.Konings*
Advances in Science and Technology, 24, p.381 - 392, 1999/00
no abstracts in English
Toda, Naohiro*; Katayama, Yoshinori; Tsuji, Kazuhiko*
Review of High Pressure Science and Technology, 7, p.647 - 649, 1998/03
The electrical conductivity 
has been measured at pressures 
to 8 GPa and temperatures 
of 77-300K in evaporated amorphous Ge (a-Ge), a-Ge-Cu alloys and a-Ge-Al alloys. The dependence of is well described by a power lw at low temperatures below 150 K, which is expemcted from a multi-phonon tunneling transition process model with weak electron-lattice coupling, rather than the Mott's variable range hopping conduction model. The exponent 
in the power law changes with increasing pressure. For both a-Ge
Cu
and a-GeAl alloys, d(ln )/d show positive values in the low pressure region and negative values in the high pressure region. Results are discussed from several hopping conduction models.
Ogawa, Toru; *; Ito, Akinori; ; Sekino, Hajime; Nishi, Masahiro; Ishikawa, Akiyoshi; Akabori, Mitsuo
Journal of Alloys and Compounds, 271-273, p.670 - 675, 1998/00
Times Cited Count：7 Percentile：49.87(Chemistry, Physical)no abstracts in English
