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Tamura, Hajimu*; Shibata, Kenji*; Takahashi, Naoya; Niwa, Masakazu
JAEA-Testing 2017-001, 52 Pages, 2017/03
JAEA-Testing-2017-001.pdf:2.36MB
It is essential to understand the activity of faults in and around a target area to assess the long-term geosphere stability for geological isolation. Potassium-Argon (K-Ar) dating of fault gouge has been conducted in Tono Geoscience Center as one of the dating technique for faulting. This report includes methods for sample preparation, analyses, and age calculation on the K-Ar dating. This can contribute to an evaluation of calculated K-Ar ages.
Takahashi, Masakazu*; Masuo, Hiroshige*; Takano, Katsutoshi; Koizumi, Norikiyo
Proceedings of 11th International Conference on Hot Isostatic Pressing (HIP 2014), 4 Pages, 2014/06
As part of the research and development of Tokamak-type nuclear fusion reactors, super electromagnetic coils are required to control the plasma reaction. The structure that supports the plasmas chamber is maintained at cryogenic temperatures in liquid helium and thus must be able to withstand the extremes of this type of environment. The most promising material for this support is, SUS316LNH and at present, the only fabrication method being employed is traditional machining from solid materials. This creates a large amount of waste material with extremely long fabrication time, due to the large size of the support at 13 m in height and 8 m in width. Therefore, it is thought that by combining machining with the HIP diffusion bonding process, both waste and fabrication time can be reduced. Although this method is still under development, it is believed that a reduction of about 50% in wasted material and an about 40% in machining time can be achieved.
*; *; *; Daigo, Yoshimichi; *
PNC TN941 79-141, 198 Pages, 1979/09
When a large leak sodium-water reaction accident occurs in a steam generator of LMFBR, pressure relief piping might be received thermal shock or blocked by frozen sodium, if it is not preheated. Then, the thermal transient tests were performed using the large leak sodium water reaction test rig SWAT-1. The results are summarized as follows; (1)Four tests were executed. The water injection rate of two tests was equivalent to that of several DEG (double-ended guilotine) failure of heat transfer tubes considering the difference of evapourator inner diameters between "Monju" and SWAT-1, and in other two tests the injection ratio was equivalant to less than that of 1 DEG. (2)Flow pattern in the pressure relief piping of two large injection rate tests was as follows, void fraction was as low as that of sodium single-phase flow in its early stage of 0.2
0.3 sec., and rapidly increased to about 0.9. In case of the small injection rate tests, the stratified flow had continued for 23 sec., it was followed by hydrogen gas single-phase flow. (3)In the large injection rate tests the maximum value of heat flux was about 1
10
[kcal/(m
h)], and that of heat transfer coefficient was 310
[kcal/(mh
C)] except in its very initial stage. In case of the small tests, they were lower. (4)In the large injection rate tests, stain of outer piping surface was about 8001,50010
, which agrees with the calculation using above value as heat transfer coefficient. (5)Possibility of blockage by frozen sodium is seemed to be very little in SWAT-1 test rig.
Niwa, Masakazu; Ishimaru, Tsuneari; Kurosawa, Hideki; Shimada, Koji; Moriya, Toshifumi*; Takahashi, Kazuharu*
no journal, ,
It is suggested that fracture zones formed by fault activities have an effect on hydrologic feature of surrounding rocks. Spatial distribution and features of fracture zones in surveyed areas are informative for site selection and design of geological repositories. Here we show a case study in the Atotsugawa Fault, northern Gifu Prefecture. Field mapping in the study area indicates that the number of fracture zone is sharply reduced, and width of each fracture zones falls within 2 m, with distance of more than 500 m from the surface trace of the Atotsugawa Fault.
Kakurai, Kazuhisa; Wakimoto, Shuichi; Matsuda, Masaaki*; Ishiwata, Shintaro*; Okuyama, Daisuke*; Taguchi, Yasujiro*; Tokura, Yoshiki*; Nishi, Masakazu*; Nakajima, Taro*; Mitsuda, Setsuo*; et al.
no journal, ,
-ray emitters including 
Cs, 1; Collaborative experiment by the committee on preparation of reference materials for radioactivity analysis of JSACYonezawa, Chushiro*; Kakita, Kazutoshi*; Takahashi, Takanori*; Aono, Tatsuo*; Maeda, Satoshi; Abe, Takaaki*; Arakawa, Fumihiro*; Kiho, Nobuharu*; Akiyama, Masakazu*; Muramatsu, Isamu*; et al.
no journal, ,
no abstracts in English
Komatsu, Tetsuya; Izumida, Atsuto*; Takahashi, Takayuki*; Funatsu, Taro*; Muraki, Masahiro*; Hozo, Renya*; Nomura, Katsuhiro; Niwa, Masakazu; Sugai, Toshihiko*
no journal, ,
no abstracts in English
Unami, Kensuke*; Fukushi, Keisuke*; Takahashi, Yoshio*; Itaya, Tetsumaru*; Niwa, Masakazu
no journal, ,
K-Ar dating is generally not applicable to smectite, which is potassium-free clay mineral. However, based on multidisciplinary analyses such as XRD, TEM, exchangeable cation analysis, and XAFS, fixed potassium can exists in clay minerals in which only smectite is identified by XRD analysis.
Unami, Kensuke*; Fukushi, Keisuke*; Takahashi, Yoshio*; Niwa, Masakazu
no journal, ,
Based on our analysis of XAFS, TEM, etc., we found that our analyzed clay minerals include potassium-fixed structure like illite, even if only smectite is identified in them according to XRD analysis.