Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Initialising ...
Kokubo, Hiroki*; Ota, Hiromichi*; Nishi, Tsuyoshi*; Yamano, Hidemasa
no journal, ,
It is necessary to obtain viscosity data of eutectic molten material of boron carbide (B
C) and stainless steel (SS) for severe accident analyses. To measure the viscosity, in this study, a crucible rotational viscometer has been developed using SS316L as a mother alloy.
Kitamura, Akane
no journal, ,
We developed three types of microfabrication for fluoropolymers using ion beam irradiation. The smooth Teflon surface becomes rough by a keV ion beam irradiation. At a high fluence, needle-like protrusions were thickly formed all over the surface. When 3-MeV proton microbeam scanned on the surface along a spiral from the center, a porous conical structure was formed. It was caused by volume expansion along the ion trajectories. Ion track membranes of poly(vinylidene fluoride) (PVDF) were developed by a track etching technique using irradiation with a 330-MeV 
Ar ion beam in an oxygen atmosphere. Ion tracks were etched without any oxidant. Oxidant is essential for conventional methods but it causes serious deterioration in the quality of PVDF membranes. Therefore, our technique is useful as an oxidant-free track-etching process.
Kaneda, Tomohiro*; Yokoyama, Kenichi*; Ishijima, Yasuhiro; Ueno, Fumiyoshi; Abe, Hitoshi
no journal, ,
In spent nuclear fuel reprocessing plant, Zr/Ta dissimilar metal joint is used for connect between different devices. And it is known that Zr and Ta have susceptibility of hydrogen embrittlement. The other hand, Zr and Ta are alloyed in the dissimilar joint and it is not clear that the hydrogen embrittlement behavior of the Zr-Ta alloy. This study aims to elucidate the hydrogen embrittle behavior of the Zr-Ta alloy. Tensile tests and X-ray diffraction (XRD) were carried out after hydrogen charging in 0.9% NaCl solution. The zirconium hydride was detected by XRD analysis but embrittlement was not shown by tensile tests. However, brittle fracture patterns were observed by SEM observation at the fracture surface the specimen after tensile test. It is consider that these results suggest the zirconium hydride that formed by hydrogen charging dominates the hydrogen embrittlement behavior of the Zr-Ta alloy.
Tsuru, Tomohito; Yamaguchi, Masatake; Itakura, Mitsuhiro; Chrzan, D.*
no journal, ,
The properties of the dislocation/solute interaction are rooted in the electronic structure of the alloys. We investigated the interaction energy between a screw dislocation and solutes using first-principles calculations. The influence of several solutes such as Al, V and Fe on mechanical properties are especially discussed as typical solute of Ti alloys.
Itakura, Mitsuhiro; Yamaguchi, Masatake
no journal, ,
no abstracts in English
Suzudo, Tomoaki; Tsuru, Tomohito; Hasegawa, Akira*
no journal, ,
Tungsten is a promising candidate for plasma-facing materials for the first wall and the divertor of future fusion reactors due to its high melting point, high sputtering resistance and low hydrogen retention. However, under irradiation, several problems have been pointed out. First, ruthenium and osmium produced by nuclear transformation form irradiated induced precipitation, and the ductility of the material is decreased. In addition, irradiation defects in tungsten serve as trapping sites for hydrogen isotopes, increasing the retention amount. However, it has also been pointed out experimentally that residual irradiation defects decrease due to the presence of rhenium, and the retention problem may be alleviated. In this presentation, we analyze the interaction of rhenium and osmium with irradiation defects by using computational method and irradiation experiment result, and we discuss the elements to be added for irradiation resistant tungsten materials.