Comprehensive model of eddy current based pressure tube to calandria tube gap measurement

该项目将专注于生成压力管（PT）与漏管（CT）间隙测量过程中涡流（EC）响应的综合理论模型，该模型用于预测CANDU燃料通道中PT和CT之间的接触时间。虽然目前燃料通道检测服务提供商对间隙测量能力进行了认证，但目前还没有综合电磁过程的物理模型，该模型包含了最重要的基本参数对间隙测量的影响。已经开发了二维（2D）分析模型，模拟平面上的EC间隙线圈，但是这些模型不能准确地再现影响间隙测量精度的许多因素。例如，弯曲的PT和CT几何形状是精确测量6-10 mm范围内间隙的关键参数，但不容易在2D中建模。为了充分解决这些弯曲的几何特征，需要建立PT与CT间隙变化的涡流响应的三维（3D）模型。经过验证的PT - CT间隙变化响应的3D涡流模型可以作为检验资格程序的一部分，通过廉价地补充实验室和现场测量，并协助量化基本参数（如压力管电阻率和壁厚变化）对间隙测量精度的影响。

This project will focus on generating a comprehensive theoretical model of the eddy current (EC) response that arises during pressure tube (PT) to calandria tube (CT) gap measurement, which is used in prediction of time-to-contact between PT and CT in CANDU fuel channels. While a gap measurement capability is presently being qualified by fuel channel inspection service providers, no comprehensive physical model of the electromagnetic processes, which incorporates the effects of the most significant essential parameters on gap measurement, exists. Two dimensional (2D) analytical models, simulating EC gap coils above a flat plane, have been developed, but these models do not accurately reproduce many of the factors that affect gap measurement accuracy. For example, the curved PT and CT geometry, a key parameter for the accurate measurement of gap in the range of 6-10 mm, is not easily modeled in 2D. A three dimensional (3D) model of the eddy current response to PT to CT gap variation is required to adequately address these curved geometry features. A validated 3D eddy current model of response to variation in PT to CT gap can be used as part of an inspection qualification program, by inexpensively supplementing laboratory and field measurements and assisting in the quantification of the effect of essential parameters such as pressure tube resistivity and wall thickness variations on gap measurement accuracy.