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Hemmi, Tsutomu; Harjo, S.; Kajitani, Hideki; Nabara, Yoshihiro; Takahashi, Yoshikazu; Nunoya, Yoshihiko; Koizumi, Norikiyo; Abe, Jun; Gong, W.; Aizawa, Kazuya; et al.
KEK Progress Report 2013-4, p.45 - 47, 2013/11
The gradual degradation was observed in the results for ITER CS conductor samples. To investigate its origin, the internal strain in the sample after the testing was successfully measured using a neutron diffraction technique non-destructively. Up to now, the transverse electromagnetic loading has been considered as an origin of the degradation due to the local bending at the high loading side (HLS). However, as a result of the neutron diffraction measurement, the large bending at the LLS of the HFZ was found. The large bending was considered as an origin of the strand buckling due to the large void generated by the transverse electromagnetic loading and the thermally induced residual compressive strain. For the improvement of the conductor performance on the strand buckling, the shorter twisting pitch (STP) can be considered. The result of the SULTAN testing of the conductor sample with STP found very effective, and the performance degradation was negligible.
Sn cable-in-conduit conductorsHemmi, Tsutomu; Harjo, S.; Ito, Takayoshi; Matsui, Kunihiro; Nunoya, Yoshihiko; Koizumi, Norikiyo; Takahashi, Yoshikazu; Nakajima, Hideo; Aizawa, Kazuya; Suzuki, Hiroshi; et al.
IEEE Transactions on Applied Superconductivity, 21(3), p.2028 - 2031, 2011/06
Times Cited Count：10 Percentile：49.97(Engineering, Electrical & Electronic)Residual strain in conductors is caused by the difference in the coefficient of expansion between NbSn strands and the jacket over a temperature range of 5 - 923 K. The superconducting properties of strands vary significantly, depending on the strain. It is important to clarify the residual strain as part of the evaluation of superconducting performance. However, the residual strain of strands in the conductor has not been measured so far because of their complicated configuration and their location in a jacket. The engineering materials diffractometer "Takumi" in J-PARC can measure residual strain with a relative accuracy of around 0.02%, using neutron diffraction. In this study, the Takumi was applied to the measurement of residual strain in strands for the ITER TF conductor. Results indicate that the residual strain of strands in the conductor can be determined, thereby clarifying the mechanism of residual strain and its relationship to superconducting performance.
Ito, Takayoshi; Harjo, S.; Osamura, Kozo*; Hemmi, Tsutomu; Awaji, Satoshi*; Machiya, Shutaro*; Oguro, Hidetoshi*; Nishijima, Gen*; Takahashi, Koki*; Matsui, Kunihiro; et al.
Materials Science Forum, 681, p.209 - 214, 2011/05
Times Cited Count：1 Percentile：52.78(Materials Science, Multidisciplinary)
standardization method; Development of irradiation silicon technology in productivity using research reactor (Joint research)Motohashi, Jun; Takahashi, Hiroyuki; Magome, Hirokatsu; Sasajima, Fumio; Tokunaga, Okihiro*; Kawasaki, Kozo*; Onizawa, Koji*; Isshiki, Masahiko*
JAEA-Technology 2009-036, 50 Pages, 2009/07
JAEA-Technology-2009-036.pdf:32.66MB
JRR-3 and JRR-4 have been providing neutron-transmutation-doped silicon (NTD-Si) by using the silicon NTD process. We have been considering to introduce the neutron filter, which is made of high-purity-titanium, into uniform doping. Silicon carbide (SiC) semiconductors doped with NTD technology are considered suitable for high power devices with superior performances to conventional Si-based devices. The impurity contents in the high-purity-titanium and SiC were analyzed by neutron activation analyses (NAA) using k standardization method. Analyses showed that the number of impurity elements detected from the high-purity-titanium and SiC were 6 and 9, respectively. Among these impurity elements, Sc detected from the high-purity-titanium and Fe detected from SiC were comparatively long half life nuclides. From the viewpoint of exposure in handling them, we need to examine the impurity control of materials.
Hayashi, Kimio; Nakagawa, Tetsuya; Onose, Shoji; Ishida, Takuya; Kodaka, Hideo; Katsuyama, Kozo; Kitajima, Toshio; Takahashi, Kozo; Tsuchiya, Kunihiko; Nakamichi, Masaru; et al.
JAEA-Technology 2008-010, 68 Pages, 2008/03
JAEA-Technology-2008-010.pdf:11.31MB
In-pile functional tests of breeding blankets for fusion reactors have been planned by Japan Atomic Energy Agency (JAEA), using a test blanket module (TBM) which will be loaded in ITER. The present report describes a conceptual investigation and a basic design of the dismantling process for irradiation capsules which were used in irradiation experiments by the Japan Materials Testing Reactor (JMTR) of JAEA. In the present design, the irradiation capsule is cut by a band saw; the released tritium is recovered safely by a purge-gas system, and is consolidated into a radioactive waste form. Furthermore, adoption of the inner-box enclosing the dismantling apparatus has brought a prospect to be able to utilize an existing hot cell (beta-
cell) equipped with usual wall material permeable to tritium, without extensive refurbishing of the cell. Thus, the present study has indicated the feasibility of the present dismantling process for the irradiated JMTR capsules containing tritium.
Maeda, Atsushi; Kowata, Koichi; Yamazaki, Yasuo; Takahashi, Kozo; Okubo, Toshiyuki; Miyazaki, Hitoshi
Dekomisshoningu Giho, (33), p.58 - 66, 2006/03
By the Japan Atomic Energy Agency (JAEA), designed decommissioning of nuclear facility and the treatment and disposal of radioactive waste will be carried out systematically and efficiently as responsibility as the installer of the nuclear power facility and generator of radioactive waste. This paper shows the present status of radioactive waste management in O-arai Research and Development Center, one of the research and development bases of JAEA. The management of low-level radioactive waste, including those accepted from outside operator of O-arai district, is carried out by the major premise of ensuring safety at O-arai Waste Management Facility. Treatment related to volume reduction and stabilization by means such as incineration and compression of solid waste, and solidification of liquid, as well as waste storage management is steadfastly promoted, so that these substances may be adequately stored and managed until they are disposed of.
Hemmi, Tsutomu; Matsui, Kunihiro; Hase, Takashi*; Koizumi, Norikiyo; Takahashi, Yoshikazu; Okuno, Kiyoshi; Suzuki, Hiroshi; Harjo, S.; Aizawa, Kazuya; Tsuchiya, Yoshinori*; et al.
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JAEA is responsible for the procurement of the CS conductor of the ITER magnet system. In order to start the procurement of the CS conductor, the performance of the CS conductor have to be demonstrated. The qualification sample has been fabricated for the test using SULTAN apparatus at the Plasma Physics Research Centre (CRPP) of the Swiss Federal Institute of Technology of Lausanne (EPFL). In this presentation, the design and the fabrication of the qualification sample is reported. The residual strain should be controlled for the measurement of the correct performance. The neutron diffraction will be applied to the direct measurement of the strain of the superconducting cable. This plan is also presented.
Harjo, S.; Aizawa, Kazuya; Ito, Takayoshi*; Abe, Jun; Osamura, Kozo*; Hemmi, Tsutomu; Jin, X.*; Nakamoto, Tatsushi*; Awaji, Satoshi*; Takahashi, Koki*
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Takahashi, Akina; Sakashita, Satoshi; Yoshida, Tadayoshi; Shiba, Kozo
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Sakashita, Satoshi; Takahashi, Akina; Yoshida, Tadayoshi; Shiba, Kozo
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Takahashi, Akina; Sakashita, Satoshi; Shiba, Kozo; Yoshida, Tadayoshi
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Sakashita, Satoshi; Takahashi, Akina; Yoshida, Tadayoshi; Shiba, Kozo
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