A liquid Li jet flowing at 15 m/s under a high vacuum of 10−3 Pa is intended to serve as a beam target (Li target) in the planned International Fusion Materials Irradiation Facility (IFMIF). The engineering validation and engineering design activities (EVEDA) for the IFMIF are being implemented under the broader approach (BA) agreement. As a major activity of the Li target facility, the EVEDA Li test loop (ELTL) was constructed by the Japan Atomic Energy Agency. A stable Li target under the IFMIF conditions (Li temperature: 523.15 K, velocity: 15 m/s, and vacuum pressure: 10−3 Pa) was demonstrated using ELTL. This study focuses on a cavitationlike acoustic noise detected in a downstream conduit where the Li target flowed under vacuum conditions. This noise was investigated using acoustic-emission (AE) sensors installed at eight locations via acoustic wave guides. The sound intensity of the acoustic noise was examined against the cavitation number of the Li target. In addition, two types of frequency analysis, namely, fast Fourier transform (FFT) and continuous wavelet transform (CWT), were performed to characterize the acoustic noise. Owing to the acoustic noise's intermittency, high frequency, and the dependence on cavitation number, we conclude that this acoustic noise is generated when cavitation bubbles collapse and/or the structural material of the pipe is cracked because of the collapse of cavitation bubbles (cavitation pitting). The location of the cavitation was fundamental for presuming the mechanism. In this study, the propagation of acoustic waves among AE sensors placed at three locations was used to localize the cavitation and a method to determine the location of cavitation was formulated. As a result, we found that cavitation occurred only in a narrow area where the Li target impinged on the downstream conduit; therefore, we concluded that this cavitation was induced by the impingement. The design of the downstream conduit of the IFMIF Li target facility should be tackled in future based on information obtained in this study.

References

References
1.
Knaster
,
J.
,
Arbeiter
,
F.
,
Cara
,
P.
,
Favuzza
,
P.
,
Furukawa
,
T.
,
Groeschel
,
F.
,
Heidinger
,
R.
,
Ibarra
,
A.
,
Matsumoto
,
H.
,
Mosnier
,
A.
,
Serizawa
,
H.
,
Sugimoto
,
M.
,
Suzuki
,
H.
, and
Wakai
,
E.
,
2013
, “
IFMIF: Overview of the Validation Activities
,”
Nucl. Fusion
,
53
(
11
), p.
116001
.
2.
Kondo
,
H.
,
Furukawa
,
T.
,
Hirakawa
,
Y.
,
Iuchi
,
H.
,
Kanemura
,
T.
,
Ida
,
M.
,
Watanabe
,
K.
,
Horiike
,
H.
,
Yamaoka
,
N.
,
Matsushita
,
I.
,
Wakai
,
E.
, and
Nakamura
,
K.
,
2012
, “
Completion of IFMIF/EVEDA Lithium Test Loop Construction
,”
Fusion Eng. Des.
,
87
(5–6), pp.
418
422
.
3.
Kondo
,
H.
,
Kanemura
,
T.
,
Furukawa
,
T.
,
Hirakawa
,
Y.
,
Groeschel
,
F.
, and
Wakai
,
E.
,
2014
, “
The Start-Up and Observation of the Li Target in the EVEDA Li Test Loop
,”
Fusion Eng. Des.
,
89
(7–8), pp.
1688
1693
.
4.
Kondo
,
H.
,
Kanemura
,
T.
,
Furukawa
,
T.
,
Hirakawa
,
Y.
,
Wakai
,
E.
,
Groeschel
,
F.
,
Nitti
,
F.
, and
Knaster
,
J.
,
2015
, “
Validation of IFMIF Liquid Li Target for IFMIF/EVEDA Project
,”
Fusion Eng. Des.
, 96–97, pp. 117–122.
5.
Kanemura
,
T.
,
Kondo
,
H.
,
Hoashi
,
E.
,
Yoshihashi-Suzuki
,
S.
,
Yamaoka
,
N.
,
Horiike
,
H.
,
Furukawa
,
T.
,
Hirakawa
,
Y.
, and
Wakai
,
E.
,
2014
, “
Evaluation of Applicability of Laser-Based Distance Meter to Measure Li-Jet Thickness for IFMIF/EVEDA Project
,”
Fusion Eng. Des.
,
89
(7–8), pp.
1642
1647
.
6.
Kanemura
,
T.
,
Kondo
,
H.
,
Furukawa
,
T.
,
Hirakawa
,
Y.
,
Hoashi
,
E.
, and
Yoshihashi
,
S.
,
2015
, “
Measurement of Li Target Thickness in the EVEDA Li Test Loop
,”
Fusion Eng. Des.
,
98–99
, pp. 1991–1997.
7.
Kondo
,
H.
,
Kanemura
,
T.
,
Furukawa
,
T.
,
Hirakawa
,
Y.
, and
Wakai
,
E.
,
2015
, “
Measurement of Cavitation in a Downstream Conduit of the Liquid Lithium Target for International Fusion Materials Irradiation Facility
,”
23rd International Conference on Nuclear Engineering
, Chiba, Japan, May 17–21, Paper No. ICONE23-1110.
8.
Kondo
,
H.
,
Furukawa
,
T.
,
Hirakawa
,
Y.
,
Nakamura
,
K.
,
Ida
,
M.
,
Watanabe
,
K.
,
Kanemura
,
T.
,
Wakai
,
E.
,
Horiike
,
H.
,
Yamaoka
,
N.
,
Sugiura
,
H.
,
Terai
,
T.
,
Suzuki
,
A.
,
Yagi
,
J.
,
Fukada
,
S.
,
Nakamura
,
H.
,
Matsushita
,
I.
,
Groeschel
,
F.
,
Fujishiro
,
K.
,
Garin
,
P.
, and
Kimura
,
H.
,
2011
, “
IFMIF/EVEDA Lithium Test Loop: Design and Fabrication Technology of Target Assembly as a Key Component
,”
Nucl. Fusion
,
51
(
12
), p.
123008
.
9.
Kondo
,
H.
,
Furukawa
,
T.
,
Hirakawa
,
Y.
,
Iuchi
,
H.
,
Ida
,
M.
,
Yagi
,
J.
,
Suzuki
,
A.
,
Fukada
,
S.
,
Matsushita
,
I.
, and
Nakamura
,
K.
,
2011
, “
Design of Purification Loop and Traps for the IFMIF/EVEDA Li Test Loop: Design of Cold Trap
,”
Fusion Eng. Des.
,
86
(9–11), pp.
2437
2441
.
10.
Furukawa
,
T.
,
Hirakawa
,
Y.
,
Kato
,
S.
,
Iijima
,
M.
,
Ohtaka
,
M.
,
Kondo
,
H.
,
Kanemura
,
T.
, and
Wakai
,
E.
,
2014
, “
Current Status of the Technology Development on Lithium Safety Handling Under IFMIF/EVEDA
,”
Fusion Eng. Des.
,
89
(
12
), pp.
2902
2909
.
11.
Kondo
,
H.
,
Furukawa
,
T.
,
Hirakawa
,
Y.
,
Iuchi
,
H.
,
Ida
,
M.
,
Watanabe
,
K.
,
Kanemura
,
T.
,
Horiike
,
H.
,
Yamaoka
,
N.
,
Mastushita
,
I.
,
Wakai
,
E.
, and
Nakamura
,
K.
,
2011
, “
Engineering Design of IFMIF/EVEDA Lithium Test Loop: Electro-Magnetic Pump and Pressure Drop
,”
19th International Conference on Nuclear
, Chiba, Japan, May 16–19, Paper No. ICONE19-43111.
12.
Wolfram Mathematica Documentation Center
,
2017
, “ContinuousWaveletTransform,” Champaign, IL, accessed Dec. 25,
2014
, http://reference.wolfram.com/language/ref/ContinuousWaveletTransform.html
13.
JIS
,
1991
, “
General Tolerances—Part 1: Tolerances for Linear and Angular Dimensions Without Individual Tolerance Indications
,” Japanese Industrial Standards, Tokyo, Japan, Standard No. JISB0405-1991.
14.
Gol'Tsova
,
E. I.
,
1966
, “
Densities of Lithium, Sodium, and Potassium at Temperatures up to 1500–1600 °C
,”
High Temp.
,
4
, p.
348
.
15.
Shpil'rain
,
E. E.
,
Soldatenko
,
Y. A.
,
Yakimovich
,
K. A.
,
Fomin
, V
. A.
,
Savhenko
,
V. A.
,
Belova
,
A. M.
,
Kagan
,
D. N.
, and
Dvaniova
, I
. F.
,
1965
, “
Experimental Investigation of Thermal and Electrical Properties of Liquid Alkali Metals at High Temperatures
,”
High Temp.
,
3
, p.
870
.
16.
Bohdansly
,
J.
, and
Schins
,
H. E. J.
,
1967
, “
Vapor Pressure of Different Metals in the Pressure Range of 50 to 4000 Torr
,”
J. Phys. Chem.
,
71
(
2
), pp.
215
217
.
17.
Bohdansly
,
J.
, and
Schins
,
H. E. J.
,
1967
, “
The Surface Tension of the Alkali Metals
,”
J. Inorg. Nucl. Chem.
,
29
(
9
), pp. 2173–2179.
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