New technique permits on-line detection of wear

Metal loss or wastage in fossil fuel plants - caused by solid particle erosion, corrosion, and wear - limits the life of boiler tubes, turbine blades and nozzles, bearings, valves and many other components. With on-line monitoring methods that directly measure the wastage rates of key components, utilities can replace worn parts or take corrective action before inservice failure occur. EPRI and its contractor, have developed wastage monitoring techniques based on the principle of surface layer activation (SLA). These techniques use an accelerator ion beam to generate radionuclides in selected surface and subsurface locations of a component without affecting its mechanical properties. The induced radionuclides emit characteristic gamma rays that are strong enough to detect yet safe for personnel. As the component wears, the loss of activated atoms reduces gamma ray intensity.