Fiber Bragg grating sensors for real-time monitoring of boiler U-bend tubes thinning

In this paper, various types of non-destructive inspection techniques have been discussed. We also experimentally investigate the usage of optical sensors as a non-destructive approach towards tube boiler inspection. The experiment has been carried out onto a carbon steel U-tube with sensors being installed at critical positions of the tubes. It was observed that different thicknesses along the curved section of the U-tube could be distinguished at room temperature after processing the sensed signal which gives an idea of monitoring the thinning of the u-tubes. This technology is supposed to have an upper edge over existing NDT/NDI technologies regarding its form-factor, detection speed and accuracy, cost-effectiveness, and tube diameter requirement.