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2008
Conference Paper
Titel
Current NDT research & development for NPP inspections
Abstract
The current dynamic process in computing, microelectronics, smart sensors and automation provide NDT system engineers with challenging opportunities for improved NDT solutions. We focus on the quantification of inspection results with respect to flaw type, flaw location and flaw size, at high inspection speeds. We strive to conquer traditional inspection limitations, such as the ultrasonic inspection of non-accessible component areas, and we may be able to assess the variations of material conditions caused by fatigue or by radiation-induced embrittlement, to name a few. For nuclear engineering, risk based NDT has become an important procedure to optimize the contribution of NDT to nuclear safety concepts. We present first results of a 3-Dimensional Ultrasonic Tomography technique with high-resolution discontinuity images comprising all arbitrary scan angles at standard inspection speeds, which will help to evaluate findings in pressurized components and will help to avoid repairs that may even cause further degradation in the component's quality. Quantitative NDT (QNDT) may become part of a general probabilistic approach to assess the failure risk, and will also help gain to understand the value of NDT in quantitative figures. Based on integrated computing tools, we present a manually performed ultrasonic inspection with 3-dimensional tomography images, comparable to conventional manipulator-controlled inspections. The ultrasonic signals are analyzed to determine transducer positions and their changes at the accuracy required to apply synthetic aperture focusing techniques (Acoustic Mouse). To analyze neutron embrittlement, we discuss initial ideas to measure this type of material degradation with scanning techniques. We evaluate the embrittlement through the cladding by analyzing the magnetostrictive properties of the material.