Cheong Yong-Moo, Lee Dong-Hoon, Jung Hyun-Kyu
Korea Atomic Energy Research Institute, 150 Dukjin-dong Yusong-ku, Daejon 305-353, South Korea.
Ultrasonics. 2004 Apr;42(1-9):883-8. doi: 10.1016/j.ultras.2004.01.073.
The dispersion curves for the feeder pipes in PHWR nuclear power plants were determined. The wave modes used for the detection of notches in the feeder pipe were confirmed as F(m,2) and/or L(0,1) by an analysis of short time Fourier transformation (STFT). The axial notches in the straight pipe were not detectable, but an axial notch in a bent pipe was detected with the mode at the frequency of 500 kHz. Initial F(m,2) and/or L(0,1) modes contains a circumferential displacement and might be converted to certain complicated modes in the bent region, which is sensitive to the axial notch. The circumferential guided wave technique was also applied for quantitative evaluation of the axial notches. The waves generated by a rocking motion of the transducer along the circumferential direction were estimated as the circumferential guided waves after a review of the acquired data and the dispersion curves.
确定了压水堆核电站中馈水管的频散曲线。通过短时傅里叶变换（STFT）分析，确认用于检测馈水管中缺口的波模为F(m,2)和/或L(0,1)。直管中的轴向缺口无法检测到，但在弯曲管中，以500kHz频率的模式检测到了轴向缺口。初始的F(m,2)和/或L(0,1)模式包含周向位移，在弯曲区域可能会转换为某些对轴向缺口敏感的复杂模式。周向导波技术也被用于轴向缺口的定量评估。在查看采集的数据和频散曲线后，将换能器沿周向摆动产生的波估计为周向导波。
