Development of Methods to Measure Vibrational Stress of Small- Bore Piping with Multiple Contactless Displacement Sensors

摘要

In a nuclear power plant, where many small-bore pipings are connected to vibration sources such as pumps, it is essential to estimate vibrational stress efficiently in order to maintain safe plant operation. In this study, the method to measure vibrational stress and the extrapolation method to estimate vibrational stress at the root section by multiple contactless displacement sensors were proposed, and its applicability was examined using vibration tests. Then the examination results were confirmed by an analytical approach. The results obtained were summarized as follows: (1) the stress measured by the proposed method agreed closely with those measured by strain gauges; and (2) the proposed extrapolation method could be applied to estimate the stress at the root section of small-bore piping.