ULTRASONIC THICKNESS MEASUREMENT OF POWER-STATION BOILER TUBES USING ELECTROMAGNETIC ACOUSTIC TRANSDUCERS

Ageing coal-fired power station boilers require a considerable amount of life management because of environmental conditions, whether due to fuel combustion, heat, water chemistry and so on. This life managemen t includes regular non-destructive testing surveys, particularly monit oring of the wall thickness of boiler tubes by ultrasonics in suscepti ble or targeted locations. In turn, this requires a significant amount of expenditure on surface preparation, often considerably more than t he cost of inspection. With this in mind, National Power plc has for s ome time been interested in exploiting non-contact NDT Techniques for wall thickness monitoring, thus minimising these costs. This paper des cribes such an application using Electromagnetic Acoustic Transducers (EMATs) that has been developed by Warwick University within a DTI-fun ded Teaching Company Scheme.