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Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Shibata, Daisuke*; Kojima, Kazuo*; Hasegawa, Takehiko*; Sato, Seiichi*; Fukaya, Akane*; Hatakeyama, Kiyoshi*
JAEA-Research 2023-004, 45 Pages, 2023/09
The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. To understand the chemical stability of simulated waste glasses, XANES spectra of B K-edge, Fe L, L-edge, and Cs M, M-edge were measured on the glass surface exposed to the leachate. As a result, it was found that the glass surface exposed to the leachate was changed and it was difficult to obtain a clear XANES spectrum. From the B K-edge XANES spectra on glass surfaces exposed to the leachate, an increase in three-coordination of B-O (BO) and a decrease in four-coordination of B-O (BO) were observed compared to the glass surfaces before immersion. The XANES spectra of Fe L, L-edge, and Cs M, M-edge show that as the exposure time in the leachate increases, the Cs present on the glass surface dissolves into the leachate. The XANES spectra of Si K-edge were measured on simulated waste glass surfaces before immersion, and it was confirmed that the change in XANES spectra given by NaO concentration had a larger effect than the waste component concentration.
Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*
JAEA-Research 2022-008, 37 Pages, 2022/10
The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the chemical state regarding boron (B), silicon (Si) and waste elements of iron (Fe), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of simulated waste glass surfaces after immersion test to investigate the long chemical stability. (1) As the leaching time of glass samples in immersion test passed, the Cs M, M-edge XANES spectra disappeared and the Fe L, L-edge spectra changed. (2) A new compound was formed on the sample surface after the immersion test, and these changes in the surface state were confirmed by Raman spectroscopy. However, it became difficult to obtain a clear B K-edge XANES spectrum by forming a compound on glass surfaces. The Si K-edge XANES spectra of borosilicate glass frits with different NaO content were measured, and following was confirmed. (1) As the NaO concentration increases in borosilicate glass frit, the K-edge peak of Si shifts to the low energy side. (2) The intensity of the Si K-edge peak is maximum when the NaO content in glass frits was about 7wt%.
Ogawa, Fumio*; Nakayama, Yuta*; Hiyoshi, Noritake*; Hashidate, Ryuta; Wakai, Takashi; Ito, Takamoto*
Transactions of the Indian National Academy of Engineering (Internet), 7(2), p.549 - 564, 2022/06
The strain energy-based life evaluation method of Mod. 9Cr-1Mo steel under non-proportional multiaxial creep-fatigue loading is proposed. Inelastic strain energy densities were calculated as the areas inside the hysteresis loops. The effect of mean-stress has been experimentally considered and the relationship between inelastic strain energy densities and creep-fatigue lives was investigated. It was found from the investigation of hysteresis loops, the decrease in maximum stress leads to prolonged failure life, while stress relaxation during strain holding causes strength reduction. The correction method of inelastic strain energy density was proposed considering the effect of maximum stress in hysteresis loop and minimum stress during strain holding, and strain energy densities for uniaxial and non-proportional multiaxial loading were obtained. Based on these results, the mechanisms governing creep-fatigue lives under non-proportional multiaxial loading have been discussed.
Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Ota, Toshiaki*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*
JAEA-Research 2021-010, 62 Pages, 2022/01
The local structure of glass-forming elements and waste elements in borosilicate glasses varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the local structure and chemical state regarding boron(B), oxygen(O), silicon(Si) and waste elements of iron(Fe), cesium(Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of prepared glass frit and simulated waste glass samples: (1) The effect of NaO concentration on B-O coordination structure is greater than that of the waste elements concentration. (2) The height of pre-edge by O K-edge spectrum depends on the concentration of first transition elements such as Fe in glass samples. Following results were obtained by XAFS measurements of simulated waste glass samples after immersion test to investigate the long chemical stability. (1) A new compound was formed on the sample surface after the immersion test, and changes in the surface state were confirmed by Raman spectroscopy. (2) Cs on the sample surface after immersion test dissolves into the leaching solution. The Si K-edge XANES spectra of borosilicate glass frits and simulated waste glass samples included lanthanides oxide were measured, and following was confirmed. (1) As the NaO concentration increases in borosilicate glass frit, the K-edge peak of Si shifts to the low energy side. (2) The peak height of the K-edge of Si differs depending on the kind of lanthanide.
Nakayama, Yuta*; Ogawa, Fumio*; Hiyoshi, Noritake*; Hashidate, Ryuta; Wakai, Takashi; Ito, Takamoto*
ISIJ International, 61(8), p.2299 - 2304, 2021/08
Times Cited Count:3 Percentile:35.36(Metallurgy & Metallurgical Engineering)This study discusses the creep-fatigue strength for Mod.9Cr-1Mo steel at a high temperature under multiaxial loading. A low-cycle fatigue tests in various strain waveforms were performed with a hollow cylindrical specimen. The low cycle fatigue test was conducted under a proportional loading with a fixed axial strain and a non-proportional loading with a 90-degree phase difference between axial and shear strains. The low cycle fatigue tests at different strain rates and the creep-fatigue tests at different holding times were also conducted to discuss the effects of stress relaxation and strain holding on the failure life. In this study, two types of multiaxial creep-fatigue life evaluation methods were proposed: the first method is to calculate the strain range using Manson's universal slope method with considering a non-proportional loading factor and creep damage; the second method is to calculate the fatigue damage by considering the non-proportional loading factor using the linear damage law and to calculate the creep damage from the improved ductility exhaustion law. The accuracy of the evaluation methods is much better than that of the methods used in the evaluation of actual machines such as time fraction rule.
Nagai, Takayuki; Okamoto, Yoshihiro; Yamagishi, Hirona*; Ota, Toshiaki*; Kojima, Kazuo*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*
JAEA-Research 2020-009, 48 Pages, 2020/09
The local structure of glass-forming elements and waste elements in waste glass varies with its chemical composition. In this study, borosilicate glass frit and simulated waste glass samples were prepared and the local structure and chemical state regarding boron (B), oxygen (O), and waste elements of cerium (Ce), cesium (Cs) were estimated by using XAFS measurement in soft X-ray region. Following results were obtained by XAFS measurements of prepared glass frit and simulated waste glass samples: (1) The existence ratio of four coordinate sp structure (BO) tends to increase with increasing NaO content in glass samples. (2) The height of a pre-edge which appears by K-edge XANES spectrum of O is so high that the Fe content in glass samples. Following results were obtained by XAFS measurements of simulated waste glass samples after immersion test to investigate long chemical stability. (1) The existence ratio of four coordinate sp structure (BO) increases by immersion test. (2) Ce which exists in the surface layer is oxidized by immersion test, and much of Cs in surface layer is lost after leach testing. Even if the glass frit form (fiber cartridge or beads) and manufacturing method were changed and a glass sample of the similar chemical composition was prepared, these observed Raman spectra of samples were different.
Iida, Kazuki*; Kofu, Maiko; Suzuki, Katsuhiro*; Murai, Naoki; Kawamura, Seiko; Kajimoto, Ryoichi; Inamura, Yasuhiro; Ishikado, Motoyuki*; Hasegawa, Shunsuke*; Masuda, Takatsugu*; et al.
Journal of the Physical Society of Japan, 89(5), p.053702_1 - 053702_5, 2020/05
Times Cited Count:17 Percentile:81.64(Physics, Multidisciplinary)Nagai, Takayuki; Sasage, Kenichi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Yamagishi, Hirona*; Ota, Toshiaki*; Inose, Takehiko*; Sato, Seiichi*; Hatakeyama, Kiyoshi*; Takahashi, Tomoe*; et al.
JAEA-Research 2019-003, 94 Pages, 2019/09
The local structures of glass-forming elements and waste elements would change by the chemical composition of waste glass including those elements. In this study, simulated waste glass samples were prepared from borosilicate glass frit including phosphorus (P) or vanadium (V), and we investigated local structures of boron, sodium, and waste elements in these P glass and V glass samples by using synchrotron XAFS measurements in soft and hard X ray region.
Kanayama, Hideyuki*; Hiyoshi, Noritake*; Ogawa, Fumio*; Kawabata, Mie*; Ito, Takamoto*; Wakai, Takashi
Zairyo, 68(5), p.421 - 428, 2019/05
This study presents creep damage assessment method for Mod. 9Cr-1Mo steel by sampling creep testing with thin plate specimen. Tensile creep rupture tests were performed using three different sizes of specimen under two different test environments to verify the creep testing with the thin plate specimen. Time to rupture of Mod. 9Cr-1Mo steel using three different sizes were almost same. In addition, there was no effect of environment on time to rupture. Pre-damaged thin plate specimens were machined from a bulk specimen's gage section that pre-damage test was performed with. Pre-damage based on life fraction rule were 8%, 16% and 25%. No effect of the process of machining pre-damaged specimen on time to rupture was confirmed by verification tests in same test condition as pre-damage test. Stress acceleration creep rupture tests were performed to estimate creep damage assessment. Creep damage assessment by stress acceleration creep rupture tests was sufficiently accurate estimate. Creep damage assessments by Vickers hardness and lath width were compared with the assessment by stress acceleration creep rupture tests to study applicability of these methods.
Nagai, Takayuki; Kobayashi, Hidekazu; Shimamura, Keisuke; Oyama, Koichi; Sasage, Kenichi; Okamoto, Yoshihiro; Shiwaku, Hideaki; Yamanaka, Keisuke*; Ota, Toshiaki*
JAEA-Research 2018-005, 72 Pages, 2018/09
Addition of radioactive waste to a borosilicate glass frit affects the local structures of glass-forming elements and waste elements in a waste glass produced in a vitrification process. In this study, simulated waste glass samples were prepared from borosilicate glass frit including phosphorus pentaoxide, and we investigated local structures of sodium (Na), boron (B), and waste elements in these glass samples by using synchrotron XAFS measurements in soft and hard X ray region.
Murai, Naoki; Suzuki, Katsuhiro*; Ideta, Shinichiro*; Nakajima, Masamichi*; Tanaka, Kiyohisa*; Ikeda, Hiroaki*; Kajimoto, Ryoichi
Physical Review B, 97(24), p.241112_1 - 241112_6, 2018/06
Times Cited Count:5 Percentile:26.15(Materials Science, Multidisciplinary)We use inelastic neutron scattering (INS) to investigate the effect of electron correlations on spin dynamics in iron-based superconductor BaKFeAs. Our INS data show a spin-wave-like dispersive feature, with a zone boundary energy of 200 meV. A first principles analysis of dynamical spin susceptibility, incorporating the mass renormalization factor of 3, as determined by angle-resolved photoemission spectroscopy, provides a reasonable description of the observed spin excitations. This analysis shows that electron correlations in the Fe-3d bands yield enhanced effective electron masses, and consequently, induce substantial narrowing of the spin excitation bandwidth. Our results highlight the importance of electron correlations in an itinerant description of the spin excitations in iron-based superconductors.
Inoue, Rintaro*; Kanaya, Toshiji*; Yamada, Takeshi*; Shibata, Kaoru; Fukao, Koji*
Physical Review E, 97(1), p.012501_1 - 012501_6, 2018/01
Times Cited Count:9 Percentile:63.13(Physics, Fluids & Plasmas)In this study, we investigate the process of a polystyrene thin film using inelastic neutron scattering (INS), dielectric relaxation spectroscopy (DRS), and thermal expansion spectroscopy (TES). The DRS and TES measurements exhibited a decrease in glass transition temperature () with film thickness. On the other hand, an increase in was observed in INS studies. In order to interpret this contradiction, we investigated the temperature dependence of the peak frequency () of the process probed by DRS and TES. The experiments revealed an increase in the peak frequency () with decreasing film thickness in the frequency region. This observation is consistent with the observed decrease in with thickness. The discrepancy between INS and DRS or TES descriptions of the process is likely to be attributed to a decrease in the apparent activation energy with film thickness and reduced mobility, due to the impenetrable wall effect.
Nagai, Takayuki; Kobayashi, Hidekazu; Sasage, Kenichi; Ayame, Yasuo; Okamoto, Yoshihiro; Shiwaku, Hideaki; Yamanaka, Keisuke*; Ota, Toshiaki*
JAEA-Research 2017-005, 54 Pages, 2017/06
Addition of radioactive waste to a borosilicate frit affects the local structures of boron (B) and waste elements in a waste glass. Synchrotron XAFS measurement was applied to investigate the local structural changes by using simulated waste borosilicate glass samples. Following results were obtained by the B K-edge XAFS analysis. It was confirmed that B K-edge XAFS analysis enables us to discriminate sp type boron (BO) from sp type boron (BO). Addition of waste elements to a glass frit increases the percentage of BO and decreases that of BO. By decreasing the SiO/AlO ratio or increasing the (SiO+BO)/AlO ratio in the glass composition, the BO percentage increases and the BO percentage decreases. Addition of PO decreases the BO percentage and increases the BO percentage. Following results were obtained from XAFS measurement of the waste elements. Cerium (Ce) valence is more reduced with the increase of the BO content. Addition of PO has a tendency to reduce the Ce valence and to enhance deposition of Zr oxide. Deposition of ruthenium compounds separated from glass phase can not be improved by changing the BO content. This study was performed as a part of the project, "Improvement of vitrification process of high-level radioactive liquid wastes" on the foundation business of the Agency for Natural Resources and Energy.
Kanayama, Hideyuki; Hiyoshi, Noritake*; Ito, Takamoto*; Ogawa, Fumio*; Wakai, Takashi
Zairyo, 66(2), p.86 - 92, 2017/02
This study presents creep characteristics of Mod. 9Cr-1Mo steel with various sized specimens and environment. Creep tests were performed using three different sizes of specimen and three different type of testing environment. Specimens are a bulk specimen which has 6mm diameter and 30mm gage length, a miniature specimen which has 2mm diameter and 10mm gage length and a thin plate specimen which has 0.76mm thickness, 1.5mm width and 7.62mm gage length. Three different type of testing environment are air, 99.99% Ar gas and vacuum. In the same environmental condition, there was no effect of specimen size on time to rupture. Time to rupture of Mod. 9Cr-1Mo steel in Ar gas was shorter than that in air and vacuum. Oxide thickness is not dominant factor in time to rupture. Fracture mode at specimen surface in Ar gas might be dominant factor in shorter time to rupture. Effect of specimen size and environment on creep strength of Mod. 9Cr-1Mo steel was evaluated on the basis of thinning.
Koizumi, Mitsuo; Goto, Jun*; Matsuki, Seishi*; Nakamura, Shoji
Nuclear Instruments and Methods in Physics Research B, 317(Part B), p.689 - 692, 2013/12
Times Cited Count:1 Percentile:11.56(Instruments & Instrumentation)Dynamic nuclear self-polarization (DYNASP) is a phenomenon that is observed in the III-V semiconductors. When electrons in the valence band of a semiconductor are optically excited to the conduction band, quite large nuclear polarization suddenly occurs below a critical temperature. This phenomenon was theoretically predicted by Dyakonov and Perel. Our recent work predicted that the electrons excited by circularly polarized laser enhance nuclear polarization near the critical temperature. The mechanism of such a large nuclear polarization would be useful for measurements of nuclear magnetic moments of unstable nuclides. However, the experiment on DYNASP can be found only in a conference report. In order to confirm the phenomenon, we have started the study of DYNASP. Preparation of experiments on DYNASP is in progress. In this paper, we describe the present status of the study of nuclear polarization by using DYNASP from the theoretical and experimental aspects.
Imai, Suguru*; Taguchi, Kenji*; Kashiwa, Tatsuya*; Kitazawa, Toshihide*; Kato, Yoshiyuki; Segawa, Tomoomi; Suzuki, Masahiro
Denki Gakkai Rombunshi, A, 133(5), p.271 - 272, 2013/05
As a part of the nuclear fuel cycle in Japan, the mixed oxide (MOX) fuels are produced through the microwave heating of the Pu/U mixed nitrate solution obtained from spent fuels. In this work, we investigate the effect of a spacer between the bottom of cavity and solution dish in microwave oven cavity to heat unifomly Pu/U mixed nitrate solution for making MOX fuels. As a result, we show the effectiveness of inserting the spacer for a uniform heating of the solution by evaluating the top-to-bottom ratio.
Imai, Suguru*; Nakajima, Yuki*; Taguchi, Kenji*; Kashiwa, Tatsuya*; Kitazawa, Toshihide*; Suzuki, Masahiro; Segawa, Tomoomi; Fujii, Kanichi
Proceedings of 2011 International Symposium on Antennas and Propagation (ISAP 2011) (USB Flash Drive), 4 Pages, 2011/10
As a part of the nuclear fuel cycle in Japan, the mixed oxide (MOX) fuels are produced through the microwave heating of the Pu/U mixed nitrate solution obtained from spent fuels. This paper investigated the electric power absorption of the solid Pu/U mixed nitrate medium in a cylindrical oven cavity and the effect of the input polarized waves. The numerical simulations have revealed that the incidence of the circularly polarized wave improves the uniformity of the absorbed power of the medium placed in the cylindrical cavity.
Koizumi, Mitsuo; Goto, Jun*; Matsuki, Seishi*
Journal of Applied Physics, 110(1), p.013911_1 - 013911_8, 2011/07
Times Cited Count:2 Percentile:9.76(Physics, Applied)Lattice nuclei of III-V type semiconductors can be self-polarized through the contact hyperfine interaction with optically excited electrons on the conduction band at low temperatures. The effect of electrons excited with circularly polarized light is introduced to the theoretical prediction of self-polarization. We found that the degree of nuclear polarization is enhanced in comparison with the use of un-polarized light. The direction of the nuclear polarization is controlled by the orientation of the electron polarization. A hysteresis phenomenon appears in the nuclear polarization when varying the degree of electron polarization.
Koizumi, Mitsuo; Matsuki, Seishi*; Goto, Jun*; Nakamura, Shoji
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no abstracts in English
Koizumi, Mitsuo; Goto, Jun*; Matsuki, Seishi*
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no abstracts in English