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Otsuka, Satoshi; Tanno, Takashi; Oka, Hiroshi; Yano, Yasuhide; Tachi, Yoshiaki; Kaito, Takeji; Hashidate, Ryuta; Kato, Shoichi; Furukawa, Tomohiro; Ito, Chikara; et al.
2018 GIF Symposium Proceedings (Internet), p.305 - 314, 2020/05
Oxide Dispersion Strengthened (ODS) steel has been developed worldwide as a high-strength and radiation-tolerant steel used for advanced nuclear system. Japan Atomic Energy Agency (JAEA) has been developing ODS steel as the primary candidate material of Sodium cooled Fast Reactor (SFR) high burn-up fuel cladding tube. Application of high burn-up fuel to SFR core can contribute to improvement of economical performance of SFR in conjunction with volume and hazardousness reduction of radioactive waste. This paper described the current status and future prospects of ODS tempered martensitic steel development in JAEA for SFR fuel application.
Yano, Yasuhide; Sekio, Yoshihiro; Tanno, Takashi; Kato, Shoichi; Inoue, Toshihiko; Oka, Hiroshi; Otsuka, Satoshi; Furukawa, Tomohiro; Uwaba, Tomoyuki; Kaito, Takeji; et al.
Journal of Nuclear Materials, 516, p.347 - 353, 2019/04
Times Cited Count：15 Percentile：86.05(Materials Science, Multidisciplinary)9Cr-ODS steel claddings consisting of tempered martensitic matrix, showed prominent creep rupture strength at 1000 
C, which surpassed that of heat-resistant austenitic steels although creep rupture strength of tempered martensitic steels is generally lower than that of austenitic steels at high temperatures. The measured creep rupture strength of 9Cr-ODS steel claddings at 1000 C was higher than that from extrapolated creep rupture trend curves formulated using data at temperatures from 650 to 850 C. This superior strength seemed to be owing to transformation of the matrix from the 
-phase to the 
-phase. The transient burst strengths for 9Cr-ODS steel were much higher than those for 11Cr-ferritic/martensitic steel (PNC-FMS). Cumulative damage fraction analyses suggested that the life fraction rule can be used for the rupture life prediction of 9Cr-ODS steel and PNC-FMS claddings in the transient and accidental events with a certain accuracy.
Otsuka, Satoshi; Tanno, Takashi; Oka, Hiroshi; Yano, Yasuhide; Kato, Shoichi; Furukawa, Tomohiro; Kaito, Takeji
Journal of Nuclear Materials, 505, p.44 - 53, 2018/07
Times Cited Count：2 Percentile：20.93(Materials Science, Multidisciplinary)A calculation model was constructed to systematically study the effects of environmental conditions (i.e. Cr concentration in sodium, test temperature, axial temperature gradient of fuel pin, and sodium flow velocity) on Cr dissolution behavior. Chromium dissolution was largely influenced by small changes in Cr concentration (i.e. chemical potential of Cr) in liquid sodium in the model calculation. Chromium concentration in sodium coolant, therefore, should be recognized as a critical parameter for the prediction and management of Cr dissolution behavior in the sodium-cooled fast reactor (SFR) core. Because the fuel column length showed no impact on dissolution behavior in the model calculation, no significant downstream effects possibly take place in the SFR fuel cladding tube due to the much shorter length compared with sodium loops in the SFR plant and the large axial temperature gradient. The calculated profile of Cr concentration along the wall-thickness direction was consistent with that measured in BOR-60 irradiation test where Cr concentration in sodium bulk flow was set at 0.07 wt ppm in the calculation.
Ikushima, Kazuki*; Shibahara, Masakazu*; Nishikawa, Satoru*; Furukawa, Takashi*; Akita, Koichi; Suzuki, Hiroshi; Morooka, Satoshi
E-Journal of Advanced Maintenance (Internet), 9(3), p.NT87_1 - NT87_5, 2017/11
Akita, Koichi; Shibahara, Masakazu*; Ikushima, Kazuki*; Nishikawa, Satoru*; Furukawa, Takashi*; Suzuki, Hiroshi; Harjo, S.; Kawasaki, Takuro; Vladimir, L.*
Yosetsu Gakkai Rombunshu (Internet), 35(2), p.112s - 116s, 2017/06
Ikushima, Kazuki*; Kitani, Yuji*; Shibahara, Masakazu*; Nishikawa, Satoru*; Furukawa, Takashi*; Akita, Koichi; Suzuki, Hiroshi; Morooka, Satoshi
Yosetsu Gakkai Rombunshu (Internet), 35(2), p.75s - 79s, 2017/06
Ikushima, Kazuki*; Shibahara, Masakazu*; Akita, Koichi; Suzuki, Hiroshi; Morooka, Satoshi; Nishikawa, Satoru*; Furukawa, Takashi*
Welding in the World, 61(3), p.517 - 527, 2017/05
In this study, first, an analysis method to predict the behaviour of residual stress distribution on shot peening process was proposed. In the proposed method, the load distribution on the collision of shots was modelled, and it was integrated with the dynamic analysis method based on the idealized explicit FEM (IEFEM). The accuracy of the proposed analysis system was confirmed by comparing the stress distribution on the collision of a single shot with the results analyzed by ABAQUS. The thermal elastic plastic analysis method using IEFEM was applied to the analysis of residual stress distribution of multi-pass welded pipe joint. The calculated residual stress distribution was compared with the measured residual stress distribution using X-ray diffraction (XRD). As a result, it was shown that the both welding residual distribution agree well with each other. Considering the calculated welding residual stress distribution, the modification of stress distribution due to shot peening was predicted by the proposed analysis system. As a result, the similar stress distribution with measurement by XRD was obtained in case that a large number of collisions are considered.
Yano, Yasuhide; Tanno, Takashi; Oka, Hiroshi; Otsuka, Satoshi; Inoue, Toshihiko; Kato, Shoichi; Furukawa, Tomohiro; Uwaba, Tomoyuki; Kaito, Takeji; Ukai, Shigeharu*; et al.
Journal of Nuclear Materials, 487, p.229 - 237, 2017/04
Times Cited Count：37 Percentile：96.77(Materials Science, Multidisciplinary)Ultra-high temperature ring tensile tests were carried out to investigate the tensile behavior of oxide dispersion strengthened (ODS) steel claddings and wrapper materials under severe accident conditions; temperatures ranged from room temperature to 1400C which is near the melting point of core materials. The experimental results showed that tensile strength of 9Cr-ODS steel claddings was highest in the core materials at the ultra-high temperatures between 900 and 1200C, but that there was significant degradation in tensile strength of 9Cr-ODS steel claddings above 1200C. This degradation was attributed to grain boundary sliding deformation with /
transformation, which was associated with reduced ductility. On the other hand, tensile strength of recrystallized 12Cr-ODS and FeCrAl-ODS steel claddings retained its high value above 1200 C unlike the other tested materials. Present study includes the result of "R&D of ODS ferritic steel fuel cladding for maintaining fuel integrity at the high temperature accident condition" entrusted to Hokkaido University by the Ministry of Education, Culture, Sports, Science and Technology of Japan (MEXT).
Wakai, Eiichi; Watanabe, Kazuyoshi*; Ito, Yuzuru*; Suzuki, Akihiro*; Terai, Takayuki*; Yagi, Juro*; Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; et al.
Plasma and Fusion Research (Internet), 11, p.2405112_1 - 2405112_4, 2016/11
Kanemura, Takuji; Kondo, Hiroo; Furukawa, Tomohiro; Hirakawa, Yasushi; Hoashi, Eiji*; Yoshihashi, Sachiko*; Horiike, Hiroshi*; Wakai, Eiichi
Fusion Engineering and Design, 98-99, p.1991 - 1997, 2015/10
Times Cited Count：14 Percentile：75.5(Nuclear Science & Technology)A high-speed (15 m/s) liquid lithium jet is planned to be utilized as the target of two 40 MeV - 125 mA deuteron beams in the International Fusion Materials Irradiation Facility (IFMIF). The target thickness is required to be maintained within 25 
1 mm under a vacuum condition of 10
Pa. This paper reports the result of measurements of the Li-target thickness under the IFMIF condition (Li speed of 10 to 20 m/s, vacuum pressure of 10 Pa, Li temperature of 250C) in the EVEDA Li Test Loop. The target thickness was found to be 26.08 mm on average at the speed of 15 m/s at the center of the IFMIF beam footprint. As for temporal fluctuation, average and maximum amplitude at the same measurement position were 0.26 and 1.45 mm, respectively, and more than 99.7% of all amplitudes measured were within the design requirement. Therefore, it was found that the Li target fulfilled the required stability for IFMIF.
Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Hirakawa, Yasushi; Furukawa, Tomohiro; Hoashi, Eiji*; Fukada, Satoshi*; Suzuki, Akihiro*; Yagi, Juro*; Tsuji, Yoshiyuki*; et al.
Proceedings of Plasma Conference 2014 (PLASMA 2014) (CD-ROM), 2 Pages, 2014/11
In the IFMIF/EVEDA (International Fusion Materials Irradiation Facility/ Engineering Validation and Engineering Design Activity), the validation tests of the EVEDA lithium test loop with the world's highest flow rate of 3000 L/min was succeeded in generating a 100 mm-wide and 25 mm-thick free-surface lithium flow steadily under the IFMIF operation condition of a high-speed of 15 m/s at 250C in a vacuum of 10 Pa. Some excellent results of the recent engineering validations including lithium purification, lithium safety, and remote handling technique were obtained, and the engineering design of lithium facility was also evaluated. These results will advance greatly the development of an accelerator-based neutron source to simulate the fusion reactor materials irradiation environment as an important key technology for the development of fusion reactor materials.
Furukawa, Tomohiro; Kondo, Hiroo; Kanemura, Takuji; Hirakawa, Yasushi; Yamaoka, Nobuo*; Hoashi, Eiji*; Suzuki, Sachiko*; Horiike, Hiroshi*
Fusion Engineering and Design, 89(7-8), p.1674 - 1678, 2014/10
Times Cited Count：1 Percentile：8.88(Nuclear Science & Technology)One key issue in the development of the IFMIF is the corrosion/erosion of the lithium components. At Osaka University, lithium free-surface flow experiments to verify the design of the IFMIF target have been carried out, and the test assembly was operated in high-speed lithium flow for 1200 hours at 300 C. Since the test assembly is important to understand the corrosion/erosion behavior as the demonstration experimental data, the metallurgical analysis was been performed. Slight irregularities which were trace of high-speed lithium flow were observed at the tip of the nozzle. On the other hand, mottled unevenness with many micro-cracks of a few micrometer depths was observed at the inlet of the nozzle, whose velocity ratio was 0.1-0.4 as compared with the nozzle tip. It was estimated that the phenomena was caused by carburizing from liquid lithium, and it was newly proven that carbon control in lithium was also important for corrosion / erosion protection of the IFMIF components.
Kanemura, Takuji; Kondo, Hiroo; Hoashi, Eiji*; Suzuki, Sachiko*; Yamaoka, Nobuo*; Horiike, Hiroshi*; Furukawa, Tomohiro; Hirakawa, Yasushi; Wakai, Eiichi
Fusion Engineering and Design, 89(7-8), p.1642 - 1647, 2014/10
Times Cited Count：14 Percentile：70.2(Nuclear Science & Technology)In the Engineering Validation and Engineering Design Activities (EVEDA) of the International Fusion Materials Irradiation Facility (IFMIF), a device to measure thickness variation of a high-speed (15 m/s) liquid lithium (Li) jet must be developed. The required measurement precision is 0.1 mm. For this purpose, we newly focused on a laser-based distance meter. This paper describes the result of an applicability test of the new sensor conducted in the Osaka University Li Loop. In the experiment, thickness variation of a Li jet (10 mm in thickness) was measured at the sampling frequency of 500 kHz in the velocity range of 10 to 15 m/s at the Li temperature of 573 K under argon atmosphere of 0.12 MPa. To evaluate the applicability of the device, the measurement precision of the Li level was evaluated. As a result, the precision was approximately 9 
m. Thus, we concluded that the laser-based distance meter is applicable to the measurement of the Li target thickness.
Wakai, Eiichi; Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Watanabe, Kazuyoshi; Ida, Mizuho*; Ito, Yuzuru; Niitsuma, Shigeto; Edao, Yuki; et al.
Fusion Science and Technology, 66(1), p.46 - 56, 2014/07
Times Cited Count：4 Percentile：30.92(Nuclear Science & Technology)Knaster, J.*; Arbeiter, F.*; Cara, P.*; Favuzza, P.*; Furukawa, Tomohiro; Groeschel, F.*; Heidinger, R.*; Ibarra, A.*; Matsumoto, Hiroshi*; Mosnier, A.*; et al.
Nuclear Fusion, 53(11), p.116001_1 - 116001_18, 2013/11
Times Cited Count：63 Percentile：94.24(Physics, Fluids & Plasmas)The IFMIF/EVEDA project under the Broader Approach Agreement between Japan and EU aims at allowing a rapid construction phase of IFMIF in due time. The three main facilities, (1) the Accelerator Facility, (2) the Target Facility and (3) the Test Facility, are the subject of validation activities that include the construction of either full scale prototypes or smartly devised scaled down facilities that will allow a straightforward extrapolation to IFMIF needs. The installation of a Linac of 1.125 MW (125 mA and 9 MeV) of deuterons started in March 2013 in Rokkasho. The world largest liquid Li test loop is running in Oarai with an ambitious experimental programme for the years ahead. A full scale high flux test module that will house 
1000 small specimens developed jointly in Europe and Japan has been constructed in Germany together with its He gas loop. A full scale medium flux test module to carry out on-line creep measurement has been constructed in Switzerland.
Kanemura, Takuji; Kondo, Hiroo; Hoashi, Eiji*; Suzuki, Sachiko*; Yamaoka, Nobuo*; Horiike, Hiroshi*; Furukawa, Tomohiro; Hirakawa, Yasushi; Ida, Mizuho; Matsushita, Izuru*; et al.
Fusion Engineering and Design, 88(9-10), p.2547 - 2551, 2013/10
Times Cited Count：4 Percentile：32.48(Nuclear Science & Technology)In the Engineering Validation and Engineering Design Activities (EVEDA) project of the International Fusion Materials Irradiation Facility (IFMIF), thickness variation of a liquid lithium (Li) jet simulating the IFMIF Li target is to be measured in the EVEDA Li Test Loop. This paper presents fabrication and performance tests results of a contact-type liquid level sensor for measuring the jet thickness variation. The sensor can detect contacts between a probe and Li, and analysis of the contact signals yields average jet thickness and amplitude distribution. One of the key fabrication requirements is to drive the probe by 0.1 mm step with positioning precision of 0.01 mm under the vacuum condition of 10Pa. To achieve such requirements, a high torque motor reducer and a friction-reduced ball screw were selected. As a result of the performance tests, the measurement results of the positioning resolution and precision were 0.1 mm and 0.01 mm, respectively.
Kondo, Hiroo; Furukawa, Tomohiro; Hirakawa, Yasushi; Kanemura, Takuji; Ida, Mizuho; Watanabe, Kazuyoshi; Nakamura, Kazuyuki; Horiike, Hiroshi*; Yamaoka, Nobuo*; Matsushita, Izuru*; et al.
Proceedings of 24th IAEA Fusion Energy Conference (FEC 2012) (CD-ROM), 8 Pages, 2013/03
Construction and initial performance tests of EVEDA (Engineering Validation and Engineering Design Activities) Lithium Test Loop (ELTL) were completed and therefore one of the major milestones in the engineering validation toward IFMIF (International Fusion Materials Irradiation Facility) was accomplished. The ELTL, which holds 2.5-ton Li, is a proto-type of a Li target facility of the IFMIF and is the largest-ever liquid lithium loop in the history of the fusion research.
Wakai, Eiichi; Kondo, Hiroo; Sugimoto, Masayoshi; Fukada, Satoshi*; Yagi, Juro*; Ida, Mizuho; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Watanabe, Kazuyoshi; et al.
Purazuma, Kaku Yugo Gakkai-Shi, 88(12), p.691 - 705, 2012/12
no abstracts in English
Kondo, Hiroo; Furukawa, Tomohiro; Hirakawa, Yasushi; Iuchi, Hiroshi; Kanemura, Takuji; Ida, Mizuho; Watanabe, Kazuyoshi; Horiike, Hiroshi*; Yamaoka, Nobuo*; Matsushita, Izuru*; et al.
Fusion Engineering and Design, 87(5-6), p.418 - 422, 2012/08
Times Cited Count：24 Percentile：84.89(Nuclear Science & Technology)The EVEDA Li test loop (ELTL) successfully completed its construction and installation of a total of 2.5-ton Li in the frame work of the IFMIF/EVEDA as one of the ITER-BA. The construction was started on Nov. 2009 in the Oarai site of the Japan Atomic Energy Agency and completed on the middle of Nov. 2010 after passing an authority inspection by a fire department in Oarai town. Subsequently, the 2.5-ton Li was installed to the ELTL by using a glove box. The nitrogen concentration in the 2.5-ton Li was found to be 127 wppm.
Shigetomi, Hiroshi*; Oka, Kiyoshi; Oi, Hidekazu*; Furukawa, Naoto*; Yoshida, Shozo*; Kawaguchi, Ryuji*; Nagai, Akira*; Haruta, Shoji*; Yanase, Yasuhito*; Akasaka, Julia*; et al.
Nihon Reza Igakkai-Shi, 33(2), p.131 - 135, 2012/08
no abstracts in English
