Regular Articles

Full Text / References

Application of High-Frequency Ultrasonic Test to the Non-Destructive Inspection of W-Cu Bonded Interface

Noritaka YUSA, Ryouji SUZUKI¹⁾, Takashi FURUKAWA¹⁾, Masayuki TOKITANI²⁾ and Suguru MASUZAKI²⁾

Department of Quantum Science and Energy Engineering, Graduate School of Engineering, Tohoku University, 6-6-01-2 Aramaki Aza Aoba, Aoba-ku, Sendai, Miyagi 980-8579, Japan

1)

Nondestructive Evaluation Center, Japan Power Engineering and Inspection Corporation, 14-1 Benten-cho, Tsurumi-ku, Yokohama, Kanawaga 230-0044, Japan

2)

National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan

(Received 10 January 2022 / Accepted 14 February 2022 / Published 30 March 2022)

Abstract

This study evaluated the applicability of high-frequency ultrasonic tests to the non-destructive inspection of the bonded interface between a cooling pipe and a divertor monoblock. Samples prepared in this study were an ITER-grade tungsten block bonded with a 2.5 mm-thick oxygen-free copper using diffusion bonding. The high-frequency ultrasonic test was performed using an acoustic microscope. A probe, operated in pulse-echo mode, scanned the copper surface of the sample two-dimensionally. Five probes with operating frequencies ranging from 15 to 50 MHz were used. The measured ultrasonic signals were converted into ultrasonic images on the assumption that the samples had a uniform and isotropic speed of sound to evaluate reflections from the interface. Whereas an interface without any artificial flaw partly reflected ultrasonics, setting the decision threshold properly, based on the distribution of the surface echo amplitudes, enabled the smallest flaw to be detected clearly. Ultrasonic signals measured around 30 MHz showed the best signal-to-noise ratio in detecting an artificial flaw introduced at the bonding layer. The results of the ultrasonic tests were consistent with those of subsequent lock-in thermography and destructive test. However the thermography test could not detect small flaws that the high-frequency ultrasonic test confirmed.

Copyright (c) 2022 The Japan Society of Plasma Science and Nuclear Fusion Research

Keywords

non-destructive testing, divertor, cooling channel, diffusion bonding, solid state bonding, imaging, thermography

DOI: 10.1585/pfr.17.2405013

Full Text

PDF format (1.1Mbytes)

References

• [1] A. Sagara et al., Fusion Eng. Des. 29, 51 (1995).
• [2] A. Loarte, Plasma Phys. Control. Fusion 43, R183 (2001).
• [3] S. Matsuda and K. Tobita, J. Nucl. Sci. Technol. 50, 321 (2013).
• [4] V.P. Budaev, Phys. At. Nucl. 79, 1137 (2016).
• [5] Z. Sun et al., Fusion Eng. Des. 121, 60 (2017).
• [6] J. Linke et al., Matter Radiat. Extremes 4, 056201 (2019).
• [7] R.A. Pitts et al., Nucl. Mater. Energy 20, 100696 (2019).
• [8] V. Barabash et al., J. Nucl. Mater. 283-287, 1248 (2000).
• [9] I.S. Batra et al., Mater. Sci. Eng. A369, 119 (2004).
• [10] H. Kishimoto et al., Fusion Eng. Des. 136A, 116 (2018).
• [11] W. Liu et al., Fusion Eng. Des. 135A, 59 (2018).
• [12] E. Bang et al., Fusion Eng. Des. 146, 603 (2019).
• [13] D. Mianjun et al., Fusion Eng. Des. 160, 111813 (2020).
• [14] M. Tokitani et al., Nucl. Fusion 61, 046016 (2021).
• [15] N. Vignal et al., Fusion Eng. Des. 88, 1818 (2013).
• [16] X. You et al., J. Fusion Energy 34, 671 (2015).
• [17] Y. Seki et al., Fusion Eng. Des. 85, 1451 (2010).
• [18] Y. Liu et al., IEEE Trans. Plasma Sci. 46, 1366 (2018).
• [19] Ll.M. Evans et al., Fusion Eng. Des. 134, 97 (2018).
• [20] C. Pei et al., Theor. Appl. Mech. Lett. 9, 180 (2019).
• [21] P. Qi et al., Fusion Sci. Technol. 61, 314 (2012).
• [22] G. Dose et al., Fusion Eng. Des. 146, 870 (2019).
• [23] S. Roccela et al., Fusion Eng. Des. 84, 1639 (2009).
• [24] E. Visca et al., Fusion Eng. Des. 136, 1593 (2018).
• [25] M. Fursdon et al., Physica Scripta T170, 014042 (2017).
• [26] W. Wang et al., Fusion Sci. Technol. 66, 125 (2014).
• [27] N. Mou et al., Fusion Eng. Des. 169, 112670 (2021).
• [28] Japanese Patent No. 6539139.