FURTHER DEVELOPMENT OF PROBE FORFLOW-ACCELERATED CORROSION MONITORING IN POWER-PLANT FEEDWATER SYSTEMS

摘要

Development of an electrical resistance probe for monitoring Flow-Accelerated Corrosion (FAC) has been ongoing for decades. The accuracy ofwall-thickness determinations has been demonstrated, problems ofthe voltage measuring technique giving data fluctuation have been found. Thislowersthe sensitivity of corrosion measurement. A voltage measuring technique, three-point delta, was investigated and compared with a traditional resistance averaging method on two probes manufactured from two different carbon steels; typeA106B (0.019%Cr) andSTPT480 (0.001%Cr). Experiments were performedat varioustemperature from 80°Cto 220°C. Results show the three-point delta provided better R~2on the linear relation betweenresistanceand temperature. The scattering of data, for example of A106Bat ～140°C, was significantly reduced from -2.35 μΩ (via the normal average method) to ～0.7μΩ