Advanced Sensor Development for Life Assessment of Power Plants

1. Spent Life: 18 % : 33% 63% 76% Advanced Sensor Development forLife Assessment of Power Plants J. Ernesto Indacochea & Ming L. Wang, Civil & Materials Engineering National Science Foundation • The societal needs for greater energy, demand larger power outputs. Higher yields are possible by exposing plant components to higher temperatures; this will hasten materials degradation or creep and their end life. • Accurate damage appraisal is needed for effective plant maintenance and repair, as well as for remaining life assessment of components for safe operation. • The electromagnetic response of the material is affected by the microstructural changes due to damage and this is assessed by means of advanced sensors. • Systematic creep microstructural changes are induced and assessed in conjunction with their magnetic properties. The magnetic responses are measured with hysteresis curves. • The material creep damage is measured by changes in grain size, dislocations density, micro particle precipitation and coarsening, void formation, and coalescence • The microstructure changes affect the pinning factor of the magnetic domain walls (k) during magnetization; this is reflected in variations of the magnetic hysteresis curves, which is then use to estimate the creep degradation level. • Accurate identification of the stages allows for better component maintenance and remaining life prediction. • An extension of the Jiles-Atherton model of magnetic hysteresis to evaluate creep changes was attained to closely check the progress of the pinning domain factor. • In the final creep stage, void coalescence cuses the most significant changes in the magnetic hysteresis of steel. • Extend the validity of the sensor to similar failure mechanisms such as like radiation damage in nuclear power plants.