反应堆压力容器接管与筒体焊缝超声轮廓二维成像算法研究

Research on Two-Dimensional Ultrasonic Contour Imaging Algorithm for Weld between Nozzle to Shell of Reactor Pressure Vessel

核电厂复杂几何形状焊缝的超声信号位置直观显示对缺陷判断具有重要参考价值。核电厂反应堆压力容器(RPV)接管内表面通常带有一定的倾斜角度,采用传统的矩形B扫描成像算法,接管与筒体焊缝超声B/C扫描成像显示存在显示不直观、缺陷定位不准确的突出问题。本文提出了直线与直线、圆弧与椭圆弧通过圆弧相切连接的算法,利用绘制直线、弧的库函数实现轮廓的绘制并将超声信号显示在轮廓之中,形成了带轮廓的B扫描图像。通过计算在轮廓中穿过闸门线的A扫描信号的阈值,形成马鞍面形状的C扫描图像。核电厂RPV接管与筒体焊缝现场超声扫查数据验证了该算法的有效性和实用性。

The visual display of ultrasonic signal position of complex geometric welds in nuclear power plants has important reference value for defect judgment.The inner surface of the nozzle of reactor pressure vessel(RPV)in nuclear power plant usually has a certain inclination angle.By using the traditional rectangular B-scan imaging algorithm,there are some outstanding problems in ultrasonic B/C scan imaging of welds between nozzle and shell,such as unintuitive display and inaccurate defect location.In this paper,the algorithm of tangent connection between straight line and straight line,arc and elliptical arc through arc is proposed.The library function of drawing straight line and arc is used to draw the contour,and the ultrasonic signal is displayed in the contour to form a B-scan image with contour.A saddle shaped C-scan image is formed by calculating the threshold of the A-scan signal passing through the gate line in the contour.The validity and practicability of the algorithm are verified by the on-site ultrasonic scanning data of the RPV nozzle and shell weld in the nuclear power plant.