Development of a portable device for thermoelectric power measurement: Application to the testing of duplex stainless steel components

The mechanical characteristics of cast duplex stainless steel components of the primary loop of pressurized water reactors may decrease as a consequence of thermal aging which causes spinodal decomposition of the ferrite Fe-Cr-Ni solid solution. Previous studies led at EDF in collaboration with INSA have shown that thermoelectric power (TEP) is a very goad indicator of the aging state of the component. A new TEP measurement apparatus was developed in order to perform measurement in industrial conditions on large steel components. TEP measurements were made using this instrument and compared to those obtained using a conventional laboratory device. Finally, the portable device was tested with success on a real elbow of a nuclear power plant.