JOPSS - Search Results

Journal Articles

Synthesis of a Si-Al gel as a starting material of aluminosilicate solids

Sato, Junya; Shiota, Kenji*; Takaoka, Masaki*

Zairyo, 70(5), p.406 - 411, 2021/05

https://doi.org/10.2472/jsms.70.406

An aluminosilicate solid is an inorganic material that has the property of immobilizing heavy metals or radionuclides in the matrix. In this study, aluminosilicates with a Si/Al molar ratio of 0.5 was synthesized from a chemical reagent in order to produce aluminosilicate solids with a low Si/Al molar ratio, which were expected to improve the immobilization of heavy metals and radionuclides contained in the matrix. The synthesized Si-Al gel with a Si/Al molar ratio of 0.5 had little impurity content and was in an amorphous phase. In addition, the compressive strength of the aluminosilicate solid produced by the synthesized Si-Al gel showed a 5 MPa or more, confirming that it can be used as a raw material for aluminosilicate solids. The aluminosilicate solid with a Si/Al molar ratio of 1.25 had a dense surface structure from the result of BSE images and had the highest compressive strength among all samples.

Journal Articles

Applicability study of nuclear graphite material IG-430 to VHTR

Osaki, Hirotaka; Shimazaki, Yosuke; Sumita, Junya; Shibata, Taiju; Konishi, Takashi; Ishihara, Masahiro

Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 8 Pages, 2015/05

For the design on the VHTR graphite components, it is desirable to employ graphite material with higher strength. IG-430 graphite has been developed as an advanced candidate for VHTR. However, the new developed IG-430 does not have enough databases for the design of HTGR. In this paper, the compressive strength (Cs) of IG-430, one of important strengths for design data, is statistically evaluated. The component reliability is evaluated based on the safety factors defined by the graphite design code, and the applicability as the VHTR graphite material is discussed. It was found that IG-430 has higher strength (about 11%) and lower standard deviation (about 27%) than IG-110 which is one of traditional graphites used for HTGR, because the crack in IG-430 would not easy to propagate rather than IG-110. Since fracture probability for IG-430 is low, the higher reliability of core-component will be achieved using IG-430. It is expected that IG-430 is applicable for VHTR graphite material.

Journal Articles

Effective thermal conductivity of a compressed LiTiO pebble bed

Tanigawa, Hisashi; Hatano, Toshihisa; Enoeda, Mikio; Akiba, Masato

Fusion Engineering and Design, 75-79, p.801 - 805, 2005/11

https://doi.org/10.1016/j.fusengdes.2005.06.104

Times Cited Count：38 Percentile：91.02(Nuclear Science & Technology)

In order to elucidate thermo-mechanical behaviour of the blanket with the water-cooled ceramic breeders, the effective thermal conductivity of a compressed LiTiO pebble bed was measured by the hot wire method. The measurement chamber for the thermal conductivity was inserted into a tensile test-apparatus. Under controlled temperature, atmosphere and mechanical loads, the stress-strain property and the effective thermal conductivity of the pebble beds were measured simultaneously. At the temperatures ranging from 673 to 973K, increases of the effective thermal conductivity due to the compressive deformation were confirmed. In addition, it was found that history of the mechanical and thermal loads on the bed affected the thermo-mechanical properties of the pebble bed.

Journal Articles

Basic concept on structural design criteria for zirconia ceramics applying to nuclear components

Shibata, Taiju; Sumita, Junya; Baba, Shinichi; Yamaji, Masatoshi*; Ishihara, Masahiro; Iyoku, Tatsuo; Tsuji, Nobumasa*

Key Engineering Materials, 297-300, p.728 - 733, 2005/11

no abstracts in English

Journal Articles

Probabilistic strength evaluation on superplastic 3Y-TZP ceramics

Baba, Shinichi; Shibata, Taiju; Yamaji, Masatoshi*; Sumita, Junya; Ishihara, Masahiro; Motohashi, Yoshinobu*; Sawa, Kazuhiro

Nihon Kikai Gakkai Kanto Shibu Ibaraki Koenkai (2004) Koen Rombunshu (No.040-3), p.61 - 62, 2004/09

no abstracts in English

Journal Articles

Bending failure assessment of C/C composite by competing risk theory

Ishihara, Masahiro; Kojima, Takao; Hoshiya, Taiji

Proceedings of International Conference on Carbon in 2002 (Carbon2002) (CD-ROM), 6 Pages, 2002/00

Bending failure of two-dimensional C/C composite was studied by both experimental and analytical approaches. In the experiment, a bending test and observation of failure surfaces were performed. From the surface observation, three kinds of fundamental fracture modes were observed; these were tensile, compressive and shear fracture modes. In the analysis, the risk-based statistical fracture theory, so-called the competing risk theory was applied to clarify the bending failure taking account of the competition of these fracture modes. Parameters used in the theory on these fundamental fracture modes were determined by additional experiments, and the theory was applied to the bending failure prediction. As a result of this study, it is concluded that the bending failure was well predicted by the theory, and that the theory would be possible to predict the strength under stress gradient condition. Furthermore, a new strength prediction method combined with FEM code, which is applicable to arbitrary shaped structures with stress gradient, was proposed in this paper.

JAEA Reports

Melting behavior of low-level radioactive miscellaneous solid waste and characteristics of solidified products (Contract research)

Nakashio, Nobuyuki; Isobe, Motoyasu; Wakui, Takuji*; Iwata, Keiji*; Kibayashi, Tatsuyuki*; Kanazawa, Katsuo; Fukui, Toshiki; Otake, Atsushi*; Nakashima, Mikio; Hirabayashi, Takakuni*

JAERI-Research 2001-001, 19 Pages, 2001/02

JAERI-Research-2001-001.pdf:1.29MB