Continuous online monitoring of high temperature pipes and welds for creep damage and end of life warning.
A new contacting EM method that responds to changes in the electrical resistance (ACPD) or impedance (DCPD) in full-size metallic components. Conductivity changes due to advancing creep cavitation damage, even before crack growth, will result in a change in the EPD. This allows monitoring of critical components like weld repairs, to warn about imminent cracking and failure.
- Continuous online monitoring.
- Can detect subtle changes in microstructure e.g. grain size variation, creep cavitation, and even material loss through corrosion.
- Refined and tested version of the PD monitoring techniques widely used in crack growth monitoring. Shares principles with PD monitoring techniques widely used in mechanical property testing of metallic specimens.
Experimental studies on full-sized P91 pressure vessels showed that EPD :
- Provides 2-3 weeks warning of impending failure.
- Allows plant operation to be halted and components to be inspected/repaired/replaced before catastrophic failure.