On line and global structural health monitoring of high temperature steam lines

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The project aim is the early detection of creep cracking, fatigue cracking and erosion thinning in superheated steamlines in nuclear plants through the use of a continuous structural health monitoring system permanently installed on line pipe work and providing 100% pipe coverage at all times. This system (ULTRASTEAMLINE) will work through the innovative use of long range guided ultrasound with dry acoustic coupling to piezoelectric transducers with long life operation at 350C. Existing inspection practice at outages leaves many large defects undetected because 100% coverage is only reached over 10 years. The system performance target is to detect and track the growth of all defects > 0.25% of pipe wall cross sectional area and ideally > 0.05% , greatly reducing the need for inspection at outages, repairs and incidence of pipe failure , to save ~ 3.5 days per reactor pa of planned and forced outage time. Estimated potential global savings in outage costs are £1.2bnpa and the UK/EEA ROI ~ 54:1. pa.Major innovations to achieve are dry acoustic coupling and transducers able to perform at high temperstures