04aD11P
IFMIF/EVEDAリチウム試験ループにおける実証試験の進捗
2) リチウムターゲットの厚み変動計測
Progress of Activities in the IFMIF/EVEDA Lithium Test Loop2) Thickness measurement of Li target
金村卓治1, 近藤浩夫1, 古川智弘1, 平川康1, 帆足英二2, 吉橋幸子2, 堀池寛2, 若井栄一1KANEMURA Takuji1, KONDO Hiroo1, FURUKAWA Tomohiro1, HIRAKAWA Yasushi1, et al.
1

1

原子力機構, 2大阪大学
Japan Atomic Energy Agency, 2Osaka University

1. Introduction
In the framework of the Engineering Validation andEngineering Design Activities (EVEDA) of theInternational Fusion Materials Irradiation Facility(IFMIF), the EVEDA lithium (Li) test loop (ELTL),
which is the prototype of the IFMIF Li loop, wasconstructed and has been operated to validate thestability of the Li target flow and a Li purification system.
In the current IFMIF design, the Li target flows along a
concave back plate with a thickness of 25 mm and awidth of 260 mm at a velocity of 15 m/s under a vacuum
condition of 10-3 Pa. The current design requires the Litarget thickness should be maintained within 25 ± 1 mm.
This presentation focuses on the measurement results ofLi target thickness and fluctuation with a laser-based
distance meter under a pressurized condition.
2. Experiment
The measurement was performed in ELTL. The main
Li loop of ELTL produces the Li target in the Target
Assembly (TA). TA of ELTL can produce a Li jet of 25mm in thickness and 100 mm in width at a velocity of up
to 20 m/s along a concave flow channel with
gradually-changing curvature radius [1].
The measurement device used is a laser distancemeter named Optical Comb Absolute Distance Meter, aproduct of Optical Comb, Inc. Measurement precision
was experimentally estimated to be 0.02 mm formeasuring the Li target thickness.
The experiments were performed at a Li temperatureof 300 oC and at Li speeds of 10, 15, and 20 m/s, which
cover the operational range foreseen in IFMIF. The Ar
pressure was set to be 0.12 MPa (abs). The data
recording time and sampling frequency were 60 s and500 kHz, respectively. Measurement was done in theregion of -50 <= y <= 50 and -50 <= x <= 50, where theorigin (x, y) = (0, 0) is defined as the beam center and thex and y directions denote streamwise and spanwise
direction, respectively. The region corresponding to thebeam footprint of IFMIF is -20 <= y <= 20 and -25 <= x<= 25 in the present case.
3. ResultFig.1 shows the three-dimensional plot of the average
Li target thickness at 15 m/s. The z direction denotes thedepth direction (z=0 means the location of the flowchannel). As shown in the figure, the target was verysmooth on average. Average thickness was 25.80, 26.06
and 26.09 mm for 10, 15 and 20 m/s respectively at theorigin. The target slightly increased along the streamwise
direction toward the beam center, and after passing thecenter, decreased toward the downstream region. It canbe considered that this phenomenon can be attributed to
the gradually-changing channel curvature, in other words,
static pressure change along the x direction. In thevicinity of the side wall, the thickness rose toward theside wall. This means Li well wetted to the side wall.
The average and maximum wave amplitude wasapprox. 0.3 and 1.5 mm at all the velocities, whichalmost satisfies the design requirement value of 1 mm.

4. Summary
It was found that the Li target was very smooth on
average at the velocity of 10, 15, and 20 m/s. The
average thickness at the beam center was approx. 26 mm.
Average and maximum wave amplitudes were approx.
0.3 and 1.5 mm, respectively. Therefore, we confirmedthat the Li target of the current design almost satisfies thedesign requirement of the target thickness variation of 25±1 mm under Ar pressure of 0.12 MPa. The next step isto measure the Li target under a vacuum condition of
10-3 Pa.

Fig.1 Three-dimensional plot of the average thickness of
the Li target at the velocity of 15 m/s(Black symbols denote measurement data)

References[1] H. Kondo, et al, Nucl. Fusion 51 (2011) 123008.