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Journal Articles

Experimental evaluation of wall shear stress in a double contraction nozzle using a water mock-up of a liquid Li target for an intense fusion neutron source

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:0 Percentile:100(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.

Journal Articles

Conceptual design and verification of long-distance laser-probe system for Li target diagnostics of intense fusion neutron source

Kondo, Hiroo*; Kanemura, Takuji*; Hirakawa, Yasushi; Furukawa, Tomohiro

Fusion Engineering and Design, 136(Part A), p.24 - 28, 2018/11

 Times Cited Count:0 Percentile:100(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.

Journal Articles

Experimental study on cavitation of a liquid lithium jet for International Fusion Materials Irradiation Facility

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$$^{-3}$$ 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.

Journal Articles

Validation of liquid lithium target stability for an intense neutron source

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:9 Percentile:27.12(Physics, Fluids & Plasmas)

A liquid-Li free-surface stream flowing at 15 m/s under a high vacuum of 10$$^{-3}$$ 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.

Journal Articles

Dissolution behavior of lithium compounds in ethanol

Furukawa, Tomohiro; Hirakawa, Yasushi; Kondo, Hiroo; Kanemura, Takuji

Nuclear Materials and Energy (Internet), 9, p.286 - 291, 2016/12

BB2015-1402.pdf:3.16MB

 Times Cited Count:2 Percentile:69.03(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.

Journal Articles

Nitrogen hot trap design and manufactures for lithium test loop in IFMIF/EVEDA project

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

BB2015-1982.pdf:2.03MB

Journal Articles

Chemical reaction of lithium with room temperature atmosphere of various humidities

Furukawa, Tomohiro; Hirakawa, Yasushi; Kondo, Hiroo; Kanemura, Takuji; Wakai, Eiichi

Fusion Engineering and Design, 98-99, p.2138 - 2141, 2015/10

BB2014-0426.pdf:0.49MB

 Times Cited Count:5 Percentile:45.73(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.

Journal Articles

Measurement of Li target thickness in the EVEDA Li Test Loop

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:13 Percentile:13.7(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 $$pm$$ 1 mm under a vacuum condition of 10$$^{-3}$$ 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$$^{-3}$$ Pa, Li temperature of 250$$^{circ}$$C) 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.

Journal Articles

Measurement of cavitation in a downstream conduit of the liquid lithium target for international fusion materials irradiation facility

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.

Journal Articles

Current status of the technology development on lithium safety handling under IFMIF/EVEDA

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:6 Percentile:44.91(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.

Journal Articles

Status of development of Lithium Target Facility in IFMIF/EVEDA project

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 250$$^{circ}$$C in a vacuum of 10 $$^{-3}$$ 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.

Journal Articles

Metallurgical analysis of lithium test assembly operated for 1200 h

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:0 Percentile:100(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 $$^{circ}$$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.

Journal Articles

The Start-up and observation of the Li target in the EVEDA Li test loop

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:8 Percentile:33.97(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.

Journal Articles

Evaluation of applicability of laser-based distance meter to measure Li-jet thickness for IFMIF/EVEDA project

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:10 Percentile:26.44(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 $$mu$$m. Thus, we concluded that the laser-based distance meter is applicable to the measurement of the Li target thickness.

Journal Articles

Engineering validation and engineering design of lithium target facility in IFMIF/EVEDA project

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:59.06(Nuclear Science & Technology)

Journal Articles

Experimental study on lithium leakage behavior

Furukawa, Tomohiro; Otaka, Masahiko; Hirakawa, Yasushi

Proceedings of 22nd International Conference on Nuclear Engineering (ICONE-22) (DVD-ROM), 5 Pages, 2014/07

This study which consists of two kinds of experiments has been performed as one of the related technologies under the IFMIF-EVEDA. The one is the experiments on advanced lithium leak detection system, and the other is the experiments on fire-extinguishing behavior of lithium. In the experiments on advanced lithium leak detection system, the potential of the small leak detection system using a laser-induced breakdown spectroscopy has been investigated. On the fire-extinguishing behavior of lithium, fire-extinguishing performance of two kinds of carbon based extinguishants (MITEX and GRAPHEX) was investigated in the experiments.

Journal Articles

Corrosion of austenitic steel in leakage lithium

Furukawa, Tomohiro; Hirakawa, Yasushi; Kato, Shoichi

Fusion Engineering and Design, 88(9-10), p.2502 - 2505, 2013/10

 Times Cited Count:5 Percentile:52.9(Nuclear Science & Technology)

Lithium, which is used as the neutron source of the IFMIF, reacts with oxygen, nitrogen and moisture in atmosphere in case of the leakage accident. In this study, fundamental corrosion test was performed in order to obtain the corrosion behavior of austenitic stainless steel in the estimated lithium compounds. In the experiment, the lithium compounds were filled with the steel into the Tammann pipe made from Al$$_{2}$$O$$_{2}$$, and heated up to 850$$^{circ}$$C. After the test, the specimen was cleaned by alcohol, and then the weight loss measurement and metallurgical examination were performed. Intense corrosion was observed at the environmental conditions containing lithium peroxide. No corrosion was observed in Li$$_{2}$$O environment. According to the consideration based on thermodynamics, Li$$_{2}$$O cannot oxidize iron and lithium is reducing agent. Slight corrosion was observed in LiOH and Li$$_{3}$$N environments.

Journal Articles

Fabrication and performance test of contact-type liquid level sensor for measuring thickness variation of liquid lithium jet in the IFMIF/EVEDA lithium test loop

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:59.76(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 10$$^{-3}$$Pa. 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.

Journal Articles

Development of lithium target system in engineering validation and engineering design activity of the International Fusion Materials Irradiation Facility (IFMIF/EVEDA)

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

JAEA Reports

Accumulation of experiences and knowledge for sodium cleaning treatment technology

Yoshida, Eiichi; Hirakawa, Yasushi; Yatabe, Toshio

JAEA-Technology 2012-033, 177 Pages, 2012/11

JAEA-Technology-2012-033.pdf:17.98MB

In JAEA, lots of tests using sodium had been carried out on the development of sodium component systems and sodium technologies for the experimental reactor JOYO and prototype reactor MONJU. When research and development has come to the end of the first stage for these reactors, those sodium test facilities has dismantled and attached sodium has been cleaned. Lots of experiences and knowledge of sodium cleaning treatment technologies has accumulated. In order to use those experiences and knowledge effectively for future sodium technology and research on the next generation fast reactors, experiences and knowledge of sodium technologies for typical systems and components has been evaluated and knowledge related important topics has been rearranged. Based on those evaluation and rearrangement, technical guidelines of sodium cleaning treatment technologies has been proposed for the purpose of effective reference of the past experiences and knowledge.

118 (Records 1-20 displayed on this page)