APPLICATION OF THE MEANDERING WINDING MAGNETOMETER TO AN IN-SITU DETERMINATION OF AGE RELATED DEGRADATION

MANY OF THE STRUCTURES AND COMPONENTS IMPORTANT TO SAFE OPERATION OF POWER PLANTS ARE SUSCEPTIBLE TO AGE RELATED DEGRADATION. STEAM LINES SUFFER CREEP DAMAGE, INCONE STEAM GENERATOR TUBES SUFFER STRESS CORROSION CRACKING, REACTOR VESSELS BECOME EMBRITTLED, AND CYCLICALLY LOADED COMPONENTS MAY EXPERIENCE FATIGUE DAMAGE. NONDESTRUCTIVE CHARACTERIZATION OF THESE AGE RELATED DEGRADATION MECHANISMS WOULD PROVIDE THE INFORMATION REQUIRED FOR INFORMED DECISIONS REGARDING PLANT MAINTENANCE AND LIFE EXTENSION. NO TECHNIQUES EXIST THAT PROVIDE ADEQUATE INFORMATION. A NOVEL SENSOR, THE MEANDERING WINDING MAGNETOMETER (MWM), OFFERS CONSIDERABLE PROMISE AS A NEW MEANS OF NONDESTRUCTIVE, ON-LINE IN SITU MATERIAL CHARACTERIZATION. IT HAS ALREADY BEEN SHOWN TO BE CAPABLE OF PRECISE MEASUREMENTS OF CONDUCTIVITY IN NONFERROMAGNETIC MATERIALS. CONDUCTIVITY IS KNOWN TO BE SENSITIVE TO AGE RELATED DEGRADATION, AND PERMEABILITY MAY BE AS WELL. THE MWM ALSO OFFERS THE POSSIBILITY OF MEASURING DEPTH RELATED VARIATIONS IN ELECTROMAGNETIC PROPERTIES. THIS FEATURE MAY BE ESPECIALLY USEFUL AS SEVERAL FORMS OF AGE RELATED DEGRATION ARE KNOWN TO VARY WITH DEPTH. PHASE I WILL INVESTIGATE EXTENDING THE CAPABILITY OF THE MWM TO PROVIDE CONDUCTIVITY AND PERMEABILITY DATA FOR FERROMAGNETIC MATERIALS. IT WILL ALSO INVESTIGATE THE RELATIONSHIP OF MATERIAL PROPERTIES AND SENSOR RESPONSE TO FATIGUE DAMAGE, ONE FORM OF AGE RELATED DEGRADATION. PHASE II WILL EXTEND MWM INSPECTION CAPABILITIES TO ADDRESS CREEP DAMAGE. IT WILL ALSO INCLUDE INTEGRATING THE MWM SENSOR INTO A FIELD PORTABLE PROTOTYPE INSTRUMENT.