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Kondo, Hiroo*; Kanemura, Takuji*; Park, C. H.*; Oyaizu, Makoto*; Hirakawa, Yasushi; Furukawa, Tomohiro
Fusion Engineering and Design, 146(Part A), p.285 - 288, 2019/09
Times Cited Count:1 Percentile:9.69(Nuclear Science & Technology)Herein, the wall shear stress in a double contraction nozzle has been evaluated experimentally to produce a liquid lithium (Li) target as a beam target for intense fusion neutron sources such as the International Fusion Materials Irradiation Facility (IFMIF), the Advanced Fusion Neutron Source (A-FNS), and the DEMO Oriented Neutron Source (DONES). The boundary layer thickness and wall shear stress are essential physical parameters to understand erosion-corrosion by the high-speed liquid Li flow in the nozzle, which is the key component in producing a stable Li target. Therefore, these parameters were experimentally evaluated using an acrylic mock-up of the target assembly. The velocity distribution in the nozzle was measured by a laser-doppler velocimeter and the momentum thickness along the nozzle wall was calculated using an empirical prediction method. The resulting momentum thickness was used to estimate the variation of the wall shear stress along the nozzle wall. Consequently, the wall shear stress was at the maximum in the second convergent section in front of the nozzle exit.
Kondo, Hiroo*; Kanemura, Takuji*; Hirakawa, Yasushi; Furukawa, Tomohiro
Fusion Engineering and Design, 136(Part A), p.24 - 28, 2018/11
Times Cited Count:2 Percentile:19.49(Nuclear Science & Technology)In the IFMIF-EVEDA project, we designed and constructed the IFMIF-EVEDA Li Test Loop (ELTL), and we performed experiments to validate the stability of the Li target. This project required a diagnostic tool to be developed in order to examine the Li target; as such, we developed a unique laser-based method that we call the laser-probe method; this method combines a high-precision laser distance meter with a statistical data analysis method. Following the successful development of the laser-probe method, we proposes a long-distance-measurement of the laser probe method (long-distance LP method) as a diagnostics tool in off-beam conditions for IFMIF or the relevant neutron sources. In this study, the measurement uncertainty resulting from coherency of the laser in a long-distance-measurement has been verified by using stationary objects and a water jet simulating the liquid Li target.
Kondo, Hiroo; Kanemura, Takuji*; Furukawa, Tomohiro; Hirakawa, Yasushi; Wakai, Eiichi; Knaster, J.*
Journal of Nuclear Engineering and Radiation Science, 3(4), p.041005_1 - 041005_11, 2017/10
A liquid-Li free-surface stream flowing at 15 m/s under a high vacuum of 10 Pa is to serve as a beam target (Li target) for the planned International Fusion Materials Irradiation Facility (IFMIF) or other intense fusion neutron sources. This study focuses on cavitation-like acoustic noise which was detected in a conduit downstream from the Li target. This noise was measured by using acoustic-emission (AE) sensors that were installed at several locations of the conduit via acoustic wave guides. As a result, we found that cavitation occurred only in a narrow area where the Li target impinged on the downstream conduit.
Kondo, Hiroo; Kanemura, Takuji*; Furukawa, Tomohiro; Hirakawa, Yasushi; Wakai, Eiichi; Knaster, J.*
Nuclear Fusion, 57(6), p.066008_1 - 066008_10, 2017/07
Times Cited Count:18 Percentile:69.80(Physics, Fluids & Plasmas)A liquid-Li free-surface stream flowing at 15 m/s under a high vacuum of 10 Pa is to serve as a beam target (Li target) for the planned International Fusion Materials Irradiation Facility (IFMIF) or other intense fusion neutron sources. We determined that the stability of the Li target remained unchanged despite using it for an extended period of 1,561 h. This finding is regarded as a significant step toward the realization of the IFMIF and the potential use of relevant neutron sources such as A-FNS and DONES.
Furukawa, Tomohiro; Hirakawa, Yasushi; Kondo, Hiroo; Kanemura, Takuji
Nuclear Materials and Energy (Internet), 9, p.286 - 291, 2016/12
Times Cited Count:5 Percentile:41.31(Nuclear Science & Technology)In order to exchange the components which received irradiation damage during the operation at the International Fusion Materials Irradiation Facility, the adhered lithium, which is partially converted to lithium compounds such as lithium oxide and lithium hydroxide, should be removed from the components. In this study, the dissolution experiments of lithium compounds (lithium nitride, lithium hydroxide, and lithium oxide) were performed in a candidate solvent, allowing the clarification of time and temperature dependence. Based on the results, a cleaning procedure for adhered lithium on the inner surface of the components was proposed.
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
Favuzza, P.*; Antonelli, A.*; Furukawa, Tomohiro; Groeschel, F.*; Heidinger, R.*; Higashi, Takuma*; Hirakawa, Yasushi; Iijima, Minoru; Ito, Yuzuru; Kanemura, Takuji; et al.
Fusion Engineering and Design, 107, p.13 - 24, 2016/06
Times Cited Count:10 Percentile:66.02(Nuclear Science & Technology)Three different partners, ENEA, JAEA and University of Tokyo, have been involved during 2014 and 2015 in the Round Robin experimentation for the assessment of the soundness of the analitycal procedure for the determination of the Nitrogen impurities contained inside a solid Lithium sample. Two different kinds of Lithium samples, differing by about an order of magnitude in Nitrogen concentration (about 230 wppm, about 20-30 wppm), have been selected for this cross analysis. The agreement of the achieved results appears very good for what concerns the most concentrated Lithium and indicates each partner's procedure is appropriate and intrinsically able to lead to meaningful values, characterized by a relative uncertainty of just few %. The smaller agreement in the case of the less concentrated Lithium anyway points out that particular attention must be paid to reduce as much as possible any source of external contamination and highlights the importance of the proper blank subtraction.
Furukawa, Tomohiro; Hirakawa, Yasushi; Kondo, Hiroo; Kanemura, Takuji; Wakai, Eiichi
Fusion Engineering and Design, 98-99, p.2138 - 2141, 2015/10
Times Cited Count:13 Percentile:65.51(Nuclear Science & Technology)In the International Fusion Materials Irradiation Facility (IFMIF), a back plate of the target assembly will be exchanged during the in-service period. During the works, the lithium components will react chemically with the surrounding atmosphere. In this research, the chemical reaction of lithium in air, oxygen and nitrogen containing variable humidity at room temperature has been investigated to estimate the chemical reaction during the exchange works.
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:16 Percentile:77.59(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.
Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Wakai, Eiichi
Proceedings of 23rd International Conference on Nuclear Engineering (ICONE-23) (DVD-ROM), 8 Pages, 2015/05
A liquid-Li free-surface stream is to serve as a beam target (Li target) for the IFMIF. As a major activity for the Li target in the IFMIF/EVEDA, the EVEDA Li test loop (ELTL) was constructed. This study focuses on cavitation-like acoustic noise in a conduit downstream of the Li target. This noise was detected by using acoustic-emission sensors. The intensity of the noise was examined versus cavitation number of the Li target. In addition, a time-frequency analysis for the acoustic signal was performed to characterize the noise. The results are as follows: (1) the intensity of the noise was increased as decreasing the cavitation number; (2) the noise was at first intermittent in a larger cavitation number, subsequently the noise became continuous as decreasing the cavitation number; (3) the noise consisted of a number of a high frequency acoustic emission which occurred in a short duration. For these results, we conclude that cavitation occurred in the downstream conduit.
Furukawa, Tomohiro; Hirakawa, Yasushi; Kato, Shoichi; Iijima, Minoru; Otaka, Masahiko; Kondo, Hiroo; Kanemura, Takuji; Wakai, Eiichi
Fusion Engineering and Design, 89(12), p.2902 - 2909, 2014/12
Times Cited Count:10 Percentile:59.32(Nuclear Science & Technology)For the irradiation test of the candidate materials for the fusion DEMO reactor, Engineering Validation and Engineering Design Activities (EVEDA) of the International Fusion Materials Irradiation Facility (IFMIF) are performed under the Broader Approach Activities. As a major Japanese activity on the target facility of the IFMIF, the engineering validation using the EVEDA Lithium Test Loop which is the largest scale liquid lithium test loop has been started in 2012. In parallel with the design and fabrication, the research on the technology establishment for the lithium safety handling was started in 2008, as one of the related technologies under the IFMIF-EVEDA. In the research, experiments of lithium chemical reaction, experiments on lithium fire, establishment of chemical analysis of impurities in lithium and experiments on advanced lithium leak detection system were carried out. This paper describes the results of these experiments.
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.
Kondo, Hiroo; Kanemura, Takuji; Furukawa, Tomohiro; Hirakawa, Yasushi; Groeschel, F.*; Wakai, Eiichi
Fusion Engineering and Design, 89(7-8), p.1688 - 1693, 2014/10
Times Cited Count:10 Percentile:59.32(Nuclear Science & Technology)EVEDA (Engineering Validation and Engineering Design Activity) Li Test Loop, which simulates the hydraulic condition of the Li target and the purification system of the IFMIF Li facility, is under operation in a frame work of the IFMIF/EVEDA. The Li target at a velocity of 20 m/s in a pressurized condition and a vacuum condition were observed by image devices in this study.
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:15 Percentile:73.06(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.
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:2 Percentile:15.74(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.
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:29.67(Nuclear Science & Technology)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:31.43(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:28 Percentile:87.36(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.