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Sakai, Toru*; Kametaka, Masao*; Aoki, Kazuhiro; Shimada, Koji; Takagi, Hideo*
Chishitsugaku Zasshi (Internet), 130(1), p.89 - 109, 2024/04
Shear planes are formed in various orientations within fault fracture zones. The sense of shear on each shear plane can be determined from the composite planar fabrics developed around it. However, it is not possible to distinguish whether all the shear planes in a fault fracture zone were formed during the same stage of motion by observations alone, because of the scarcity of chronological data. As such, we attempted to determine the kinematic and stress histories of the Shionohira and Kuruma faults by using both observations of composite planar fabrics and stress inversion analysis. As a result, we identified five stages of motion on the Shionohira Fault and two stages of motion on the Kuruma Fault. The chronological data are not sufficient to constrain the timing of the stages, but the reconstructed histories are consistent with the paleostress fields and tectonic activity around these faults, as determined in previous studies. Although the reconstructed stress history depends on the density of fault-slip data from the measurement area, this method is effective for investigating the formation mechanisms of fault fracture zones.
O/HO vapor generator for contrast-variation neutron scatteringArima-Osonoi, Hiroshi*; Takata, Shinichi; Kasai, Satoshi*; Ouchi, Keiichi*; Morikawa, Toshiaki*; Miyata, Noboru*; Miyazaki, Tsukasa*; Aoki, Hiroyuki; Iwase, Hiroki*; Hiroi, Kosuke; et al.
Journal of Applied Crystallography, 56(6), p.1802 - 1812, 2023/12
Times Cited Count：0 Percentile：0.02(Chemistry, Multidisciplinary)Shiota, Yuki; Kudo, Junki; Tsuno, Hiromi; Takeuchi, Ryotaro; Ariyoshi, Hideo; Shiohama, Yasutaka; Hamano, Tomoharu; Takagi, Tsuyohiko; Nagaoki, Yoshihiro
JAEA-Technology 2023-002, 87 Pages, 2023/06
JAEA-Technology-2023-002.pdf:8.53MB
In the first stage of Monju decommissioning project, fuel unload work began to be carried out. There are two tasks in this work. One is Fuel Treatment and Storage work that gets rid of sodium on the fuel assemblies unloaded from Ex-Vessel fuel Storage Tank (EVST) and carries it in the storage pool, and the other is Fuel Unloading that the fuel assemblies in the reactor core is replaced with dummy fuels and stored in EVST. Fuel Treatment and Storage work and Fuel Unloading work are performed alternately, and 370 fuel assemblies in the core and 160 fuel assemblies in EVST are all carried to the storage pool. Monju had a large amount of sodium in the reactor vessel and EVST, and there was a residual risk of fuel failure due to the superposition of a large scale sodium fire. Therefore, in the first stage of the Monju decommissioning project, it was decided to take about 5.5 years to remove the residual risk by storing all the fuel rods in the fuel storage pool. There are few Fuel handling system of Sodium Fast Reactor in the world, so the driving record and experience are not enough. So, events that occur even if taken measure are assumed. The following three events apply to this; first, events that are difficult to prevent, events. Second, that are due to lack of experience, and final, events optimization of system is not enough. Plans were taken to suppress these events. This report summarizes the "Monju decommissioning project" work conducted so far in all four campaigns.
Yokoyama, Sumi*; Tatsuzaki, Hideo*; Tanimura, Yoshihiko; Yoshitomi, Hiroshi; Hirao, Shigekazu*; Aoki, Katsunori; Tachiki, Shuichi*; Ezaki, Iwao*; Hoshi, Katsuya; Tsujimura, Norio
Journal of Radiological Protection, 42(3), p.031504_1 - 031504_17, 2022/09
Times Cited Count：1 Percentile：31.61(Environmental Sciences)In Japan, the radiation-dose limit for the lens of the eye was revised in April 2021. Consequently, for workers, the numerical values of the equivalent dose to the lens of the eye are equal to those of the effective dose. Radiation workers, radiation safety officers and licensees must comply with regulations related to radiation protection and optimize protection. The new guidelines on dose monitoring of the lens of the eye developed by the Japan Health Physics Society recommend for the dose to be estimated near the eye for accurate estimation, when the dose to the lens approaches or exceeds the management criteria. However, there is limited information regarding the non-uniform exposure of nuclear power plant workers. In this study, the dose equivalents of high-dose-rate workplaces and the personal doses of 88 workers were estimated at four Japanese commercial nuclear power plant sites (RWR: 3 units and BWR: 3 units) and the dose to the lens of the eye and the exposure situations of the workers were analyzed.
Yokoyama, Sumi*; Ezaki, Iwao*; Tatsuzaki, Hideo*; Tachiki, Shuichi*; Hirao, Shigekazu*; Aoki, Katsunori; Tanimura, Yoshihiko; Hoshi, Katsuya; Yoshitomi, Hiroshi; Tsujimura, Norio
Radiation Measurements, 138, p.106399_1 - 106399_5, 2020/11
Times Cited Count：2 Percentile：24.28(Nuclear Science & Technology)Kobayashi, Keita*; Okumura, Masahiko; Yamada, Susumu; Machida, Masahiko; Aoki, Hideo*
Physical Review B, 94(21), p.214501_1 - 214501_7, 2016/12
Times Cited Count：56 Percentile：89.32(Materials Science, Multidisciplinary)no abstracts in English
Okumura, Masahiko; Yamada, Susumu; Machida, Masahiko; Aoki, Hideo*
Soryushiron Kenkyu, 119(4C), p.F99 - F101, 2012/02
no abstracts in English
Hamada, Kazuya; Nakajima, Hideo; Okuno, Kiyoshi; Endo, Sakaru*; Kikuchi, Kenichi*; Kubo, Yoshio*; Aoki, Nobuo*; Yamada, Yuichi*; Osaki, Osamu*; Sasaki, Takashi*; et al.
JAERI-Tech 2002-027, 23 Pages, 2002/03
JAERI-Tech-2002-027.pdf:2.94MB
The Engineering Design Activities (EDA) for the International Thermonuclear Experimental Reactor (ITER) was performed under the collaboration of Japan, EU, Russia and the US. The EDA was successfully completed in July 2001, in which the development of fabrication technology for advanced components, such as superconducting coils, was conducted. The ITER magnet system consists of Toroidal Field coils, a Central Solenoid (CS), Poloidal Field coils and Correction coils. The construction of these coils requires advanced technologies that fairly exceeded those available at the start of the EDA. Therefore, CS Model Coil and TF Model Coil projects were implemented. To fabricate the CS Model Coil, the fabrication technologies for high performance strand, large cable, winding, heat treatment, joint and insulation are indispensable. This report describes the above detailed fabrication technologies successfully developed in the CS Model Coil Project.
Ota, Yukihiro; Machida, Masahiko; Koyama, Tomio*; Aoki, Hideo*
no journal, ,
The discovery of iron-based superconductors has triggered the study for multi-band superconductors. Leggett's modes are expected to be important for characterizing multi-band superconductor. However, when considering the two-band model which is a minimal model for multi-band superconductors, it is characterized by only the magnitude of inter-band coupling. Thus, the relevance to 
s-wave superconductivity, which is a candidate for pairing symmetry in iron-based superconductors, is still unclear. Furthermore, a five-band model is necessary for a realistic theoretical description for iron-based superconductors. Hence, we examine Leggett's modes in a multi-band model. In particular, we focus on a three-band model, for simplicity. We reveal that two distinct classes of Leggett's modes exist under s-wave superconductivity. The difference between them is characterized via inter-band Josephson current addition or cancellation.
Ota, Yukihiro; Machida, Masahiko; Koyama, Tomio*; Aoki, Hideo*
no journal, ,
We extend Leggett's 1966 analysis for a massive out-of-phase collective mode coexisting with the Nambu-Goldstone mode in two-band superconductors to the case where there are three or more bands. Crucial, as we find here, is to classify the interband Josephson coupling energy which is the origin of the Leggett's collective modes. Namely, three-band superconductors are shown to accommodate more than one collective modes, which are classified in terms of the "dynamical class" that distinguishes the parity of the inter-band Josephson current. The mass of the multiple Leggett's modes is then shown to dramatically depend on the class.
Okumura, Masahiko; Yamada, Susumu; Machida, Masahiko; Aoki, Hideo*
no journal, ,
no abstracts in English
Ota, Yukihiro; Machida, Masahiko; Koyama, Tomio*; Aoki, Hideo*
no journal, ,
One important way to characterize multi-band superconductors should be to look at their collective modes, which are expected to reflect the broken gauge symmetry that involves multi-bands. We extend Leggett's analysis for a massive out-of-phase mode coexisting with the Nambu-Goldstone mode in two-band superconductors to the case where there are three or more bands. Crucial is to classify the inter-band Josephson coupling energy which is the origin of the Leggett's modes. Three-band superconductors are shown to accommodate more than one collective modes, which are classified in terms of the "dynamical class" that distinguishes the action of the inter-band Josephson coupling. The mass of the multiple Leggett's modes is then shown to dramatically depend on the class. We expect that the present prediction can be tested in the iron-based superconductor (with a gap function involving three bands).
Ota, Yukihiro; Machida, Masahiko; Koyama, Tomio*; Aoki, Hideo*
no journal, ,
One important way to characterize multi-band superconductors should be to look at their collective excitation modes, which are expected to reflect the broken gauge symmetry that involves multi-bands. Here we extend Leggett's analysis for a massive out-of-phase collective mode coexisting with the Nambu-Goldstone mode in two-band superconductors to the case where there are three or more bands. Crucial is to classify the inter-band Josephson coupling energy which is the origin of the Leggett's collective modes. Three-band superconductors are shown to accommodate more than one collective modes, which are classified in terms of the "dynamicalclass" that distinguishes the parity of the inter-band Josephson current. The mass of the multiple Leggett's modes is then shown to dramatically depend on the class. We expect that the present prediction can be tested in the iron-based superconductor (with a gap function involving three bands).
Nagai, Yuki; Kuroki, Kazuhiko*; Machida, Masahiko; Aoki, Hideo*
no journal, ,
no abstracts in English
Kobayashi, Keita; Okumura, Masahiko; Yamada, Susumu; Machida, Masahiko; Aoki, Hideo*
no journal, ,
no abstracts in English
Yokoyama, Sumi*; Ezaki, Iwao*; Aoki, Katsunori; Tatsuzaki, Hideo*; Hirao, Shigekazu*; Tachiki, Shuichi*; Yoshitomi, Hiroshi; Hoshi, Katsuya; Tanimura, Yoshihiko; Oguchi, Hiroyuki*; et al.
no journal, ,
no abstracts in English
Ezaki, Iwao*; Aoki, Katsunori; Tatsuzaki, Hideo*; Tachiki, Shuichi*; Hirao, Shigekazu*; Yoshitomi, Hiroshi; Hoshi, Katsuya; Tanimura, Yoshihiko; Oguchi, Hiroyuki*; Tsujimura, Norio; et al.
no journal, ,
no abstracts in English
Sakai, Toru*; Kametaka, Masao*; Aoki, Kazuhiro; Shimada, Koji; Takagi, Hideo*
no journal, ,
no abstracts in English
