Chen, L.*; Mao, C.*; Chung, J.-H.*; Stone, M. B.*; Kolesnikov, A. I.*; Wang, X.*; Murai, Naoki; Gao, B.*; Delaire, O.*; Dai, P.*
Nature Communications (Internet), 13, p.4037_1 - 4037_7, 2022/07
Motokawa, Ryuhei; Kaneko, Koji; Oba, Yojiro; Nagai, Takayuki; Okamoto, Yoshihiro; Kobayashi, Taishi*; Kumada, Takayuki; Heller, W. T.*
Journal of Non-Crystalline Solids, 578, p.121352_1 - 121352_7, 2022/02
Kim, B. K.*; Tan, L.*; Sakasegawa, Hideo; Parish, C. M.*; Zhong, W.*; Tanigawa, Hiroyasu*; Kato, Yutai*
Journal of Nuclear Materials, 545, p.152634_1 - 152634_12, 2021/03
Yamauchi, Hiroki; Sari, D. P.*; Watanabe, Isao*; Yasui, Yukio*; Chang, L.-J.*; Kondo, Keietsu; Ito, Takashi; Ishikado, Motoyuki*; Hagihara, Masato*; Frontzek, M. D.*; et al.
Communications Materials (Internet), 1, p.43_1 - 43_6, 2020/07
High-temperature short-range order is discovered up to 720 K in MnRhSi by complementary use of neutron scattering and muon spin relaxation measurements.
Iida, Kazuki*; Nagai, Yuki; Ishida, Shigeyuki*; Ishikado, Motoyuki*; Murai, Naoki; Christianson, A. D.*; Yoshida, Hiroyuki*; Inamura, Yasuhiro; Nakamura, Hiroki; Nakao, Akiko*; et al.
Physical Review B, 100(1), p.014506_1 - 014506_8, 2019/07
Magnetic excitations and magnetic structure of EuRbFeAs were investigated by neutron scattering measurements.
Chadwick, M. B.*; Capote, R.*; Trkov, A.*; Herman, M. W.*; Brown, D. A.*; Hale, G. M.*; Kahler, A. C.*; Talou, P.*; Plompen, A. J.*; Schillebeeckx, P.*; et al.
Nuclear Data Sheets, 148, p.189 - 213, 2018/02
The CIELO collaboration has studied neutron cross sections on nuclides that significantly impact criticality in nuclear facilities - U, U, Pu, Fe, O and H - with the aim of improving the accuracy of the data and resolving previous discrepancies in our understanding. This multi-laboratory pilot project, coordinated via the OECD/NEA Working Party on Evaluation Cooperation (WPEC) Subgroup 40 with support also from the IAEA, has motivated experimental and theoretical work and led to suites of new evaluated libraries that accurately reflect measured data and also perform well in integral simulations of criticality. This report summarizes our results and outlines plans for the next phase of this collaboration.
Iida, Kazuki*; Ishikado, Motoyuki*; Nagai, Yuki; Yoshida, Hiroyuki*; Christianson, A. D.*; Murai, Naoki; Kawashima, Kenji*; Yoshida, Yoshiyuki*; Eisaki, Hiroshi*; Iyo, Akira*
Journal of the Physical Society of Japan, 86(9), p.093703_1 - 093703_4, 2017/09
Yamauchi, Hiroki; Metoki, Naoto; Watanuki, Ryuta*; Suzuki, Kazuya*; Fukazawa, Hiroshi; Chi, S.*; Fernandez-Baca, J. A.*
Journal of the Physical Society of Japan, 86(4), p.044705_1 - 044705_9, 2017/04
Neutron diffraction experiments have been carried out to characterize the magnetic structures and order parameters in an intermediate phase of NdB showing the successive phase transitions at K, K, and K. The observed patterns in phase II () are successfully explained by postulating a planar structure with static magnetic moments in the tetragonal -plane. We have found that the magnetic structure in phase II can be uniquely determined to be a linear combination of noncolinear "all-in/all-out"-type and "vortex"-type antiferromagnetic structures. We propose that the quadrupolar interaction holds the key to stabilizing the noncollinear magnetic structure and quadrupolar order. Here, the frustration in the Shastry - Sutherland lattice would play an essential role in suppressing the dominance of the magnetic interaction.
Motokawa, Ryuhei; Kobayashi, Toru; Endo, Hitoshi*; Ikeda, Takashi; Yaita, Tsuyoshi; Suzuki, Shinichi; Narita, Hirokazu*; Akutsu, Kazuhiro*; Heller, W. T.*
Journal of Nuclear Science and Technology, 53(8), p.1205 - 1211, 2016/08
Motokawa, Ryuhei; Endo, Hitoshi*; Nagao, Michihiro*; Heller, W. T.*
Solvent Extraction and Ion Exchange, 34(5), p.399 - 406, 2016/07
Hirose, Takanori; Nozawa, Takashi; Stoller, R. E.*; Hamaguchi, Dai; Sakasegawa, Hideo; Tanigawa, Hisashi; Tanigawa, Hiroyasu; Enoeda, Mikio; Kato, Yutai*; Snead, L. L.*
Fusion Engineering and Design, 89(7-8), p.1595 - 1599, 2014/10
The material properties, focusing on the properties used for design analysis were re-assessed and newly investigated for various heats including F82H-IEA. Moreover, irradiation effects on those properties were studied in this work. As for thermal properties, thermal conductivity that has significant impacts on the thermo-hydraulic properties of the blanket was investigated on several heats of F82H including F82H-IEA. According to the measurements, the thermal conductivity falls in the range 28.31.1 W/m/K at 293 K. Although this is comparable with that of the other ferritic/martensitic steels, it is 20% lower than the published value for F82H-IEA. The re-assessment on the published value revealed that the thermal diffusivity was over-estimated. As for irradiation effects on the physical properties, electric resistivity was measured after irradiation up to 6 dpa at 573 K and 673 K. The reduction of resistivity in F82H and its welds were 3% and 6%, respectively.
Sekine, Yurina; Fukazawa, Tomoko*; Aizawa, Mamoru*; Kobayashi, Riki*; Chi, S.*; Fernandez-Baca, J. A.*; Yamauchi, Hiroki; Fukazawa, Hiroshi
Journal of Physical Chemistry B, 118(47), p.13453 - 13457, 2014/08
Neutron diffraction patterns for deuterated poly-,,-dimethylacrylamide (PDMAA) hydrogels were measured from 10 to 300 K to investigate the structure and properties of water in the gels. Diffraction peaks observed below 250 K indicate the existence of ice in the hydrogels. Some diffraction peaks from the ice are at lower diffraction angles than those in ordinary hexagonal ice (Ih). These shifts in peaks indicate that the lattice constants of the and axes in the ice are about 0.29% and 0.3% higher than those in ice Ih, respectively. The results show that bulk low-density ice can exist in PDMAA hydrogels. The distortions in the lattice structure of ice imply significant interactions between water molecules and the surrounding polymer chains, which play an important role in the chemical and mechanical properties of the hydrogel.
Hirose, Takanori; Sokolov, M. A.*; Ando, Masami; Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Stoller, R. E.*; Odette, G. R.*
Journal of Nuclear Materials, 442(1-3), p.S557 - S561, 2013/11
Hirose, Takanori; Okubo, Nariaki; Tanigawa, Hiroyasu; Ando, Masami; Sokolov, M. A.*; Stoller, R. E.*; Odette, G. R.*
Journal of Nuclear Materials, 417(1-3), p.108 - 111, 2011/10
This paper summarizes recent results of the irradiation experiments focused on F82H and its modified steels irradiated at 573 K. The materials used in this research were F82H-IEA and its modified steels. Post irradiation mechanical tests revealed that irradiation hardening of F82H is saturated by 9 dpa and the as-irradiated proof stress is less than 1 GPa. The deterioration of total elongation was also saturated by 9 dpa. Irradiation response of F82H-mod3, which is stable to temperature instability during material production and HIP treatment, was very similar to that of F82H-IEA, and negative impacts of extra tantalum was not observed. Therefore it can be an attractive option for the structural materials for blanket components manufactured by HIP.
Okubo, Nariaki; Sokolov, M. A.*; Tanigawa, Hiroyasu; Hirose, Takanori; Jitsukawa, Shiro; Sawai, Tomotsugu; Odette, G. R.*; Stoller, R. E.*
Journal of Nuclear Materials, 417(1-3), p.112 - 114, 2011/10
Irradiation hardening and fracture toughness of reduced-activation ferritic/martensitic steel F82H after irradiation were investigated with a focus on changing the fracture toughness transition temperature as a result of several heat treatments. The specimens were standard F82H-IEA (IEA), F82H-IEA with several heat treatments (Mod1 series) and a higher tantalum containing (0.1%) heat of F82H (Mod3). The specimens were irradiated up to 18 dpa at 300 C in High Flux Isotope Reactor under a collaborative research program between JAEA/US-DOE. The results of hardness tests showed that irradiation hardening of IEA was comparable with that of Mod3. However, the fracture toughness transition temperature of Mod3 was lower than that of IEA. The transition temperature of Mod1 was also lower than that of the IEA heat. These results suggest that tightening of specifications on the heat treatment condition and modification of the minor alloying elements seem to be effective to reduce the fracture toughness transition temperature after irradiation.
Tanigawa, Hiroyasu; Shiba, Kiyoyuki; Mslang, A.*; Stoller, R. E.*; Lindau, R.*; Sokolov, M. A.*; Odette, G. R.*; Kurtz, R. J.*; Jitsukawa, Shiro
Journal of Nuclear Materials, 417(1-3), p.9 - 15, 2011/10
ITER construction was started, and R&D toward DEMO shifted to more practical stage. On this stage, the candidate material for DEMO blanket have to be the one which have sound engineering bases to be ready for engineering designing activity for DEMO reactor in 10 years. Reduced activation ferritic/martensitic (RAFM) steels, such as F82H (Fe-8Cr-2W-0.2V-0.04Ta) or EUROFER97 (Fe-9Cr-1W-0.2V- 0.12Ta), is the only material which currently have enough potential to meet this requirement, and selected as the target material in the R&D on materials engineering for DEMO blanket under the International Fusion Energy Research Centre (IFERC) project in the Broader Approach (BA) activities between EU and Japan. In this paper, current status of RAFM R&D is overviewed especially on fabrication technology, inspection/testing technology, and material database. Overview on irradiation effect study is also provided.
Hirose, Takanori; Okubo, Nariaki; Tanigawa, Hiroyasu; Kato, Yutai*; Clark, A. M.*; McDuffee, J. L.*; Heatherly, D. W.*; Stoller, R. E.*
DOE/ER-0313/49, p.94 - 99, 2010/12
Shamoto, Shinichi; Ishikado, Motoyuki; Christianson, A. D.*; Lumsden, M. D.*; Wakimoto, Shuichi; Kodama, Katsuaki; Iyo, Akira*; Arai, Masatoshi
Physical Review B, 82(17), p.172508_1 - 172508_4, 2010/11
An optimally doped iron-based superconductor LaFeAsOF with T=29 K has been studied by inelastic powder neutron scattering. The magnetic excitation at Q = 1.15 is enhanced below T, leading to a peak at E=13 meV as the resonance mode.
Tanigawa, Hiroyasu; Sokolov, M. A.*; Sawahata, Atsushi*; Hashimoto, Naoyuki*; Ando, Masami; Shiba, Kiyoyuki; Enomoto, Masato*; Klueh, R. L.*
Journal of ASTM International (Internet), 6(5), 10 Pages, 2009/05
The master curve (MC) method works when the transition fracture toughness values follow the MC, and once the value is scaled properly, the MC is usually independent of the type of steel or the type of test specimen. This method is very much depending on the assumption that the fracture initiation points are homogeneously distributed and its initiation mechanism is independent on test temperature. The reduced-activation ferritic/martensitic steels (RAFs), such as F82H (Fe-8Cr-2W-0.2V-0.04Ta), has AlO Ta(V,Ti)O composite inclusions, or simple Ta(V)O inclusions, and shows inhomogeneous distribution, and it was revealed that that RAFs which contain Ta could initiate the facture in the different mechanism at lower temperature as the composite inclusions become fragile, and this should be considered when the toughness measured with small size toughness specimen which is usually tested at lower temperature.
Tanigawa, Hiroyasu; Klueh, R. L.*; Hashimoto, Naoyuki*; Sokolov, M. A.*
Journal of Nuclear Materials, 386-388, p.231 - 235, 2009/04
It has been reported that reduced-activation ferritic/martensitic steels (RAFMs) showed a variety of changes in ductile-brittle transition temperature and yield stress after irradiation at 573 K up to 5 dpa, and those differences could not be interpreted solely by the difference of dislocation microstructure induced by irradiation. To investigate the impact of other microstructural feature, i.e. precipitates, the precipitation behavior of F82H, ORNL 9Cr-2WVTa, and JLF-1 was examined. It was revealed that irradiation-induced precipitation and amorphization of precipitates partly occurred and caused the different precipitation on block, packet and prior austenitic grain boundaries. In addition to these phenomena, irradiation-induced nano-size precipitates were also observed in the matrix. It was also revealed that the chemical compositions of precipitates approached the calculated thermal equilibrium state of MC at an irradiation temperature of 573 K. Over all, these observations suggests that the variety of embrittlement and hardening of RAFMs observed at 573 K irradiation up to 5 dpa might be the consequence of the transition phenomena that occur as the microstructure approaches thermal equilibrium during irradiation at 573 K.