Combined thermo-electric power and resistivity measurements of embrittlement recovery in aged JRQ ferritic steel

The detection of microstructural changes by means of non-destructive techniques is a severe challenge. A significant amount of work has been carried out over the last 20 years to validate methods based on thermo-electric power and resistivity measurements. It has been shown that both thermo-electric power (TEP) and resistivity measurements have the potential to provide information and assessment of microstructural changes such as precipitation of copper and matrix damage, whereas grain boundary segregation of particular species like phosphorus remains difficult to assess. This paper investigates the possible advantages of combined TEP and resistivity measurements of embrittlement recovery due to annealing of an embrittled ferritic RPV steel. The ferritic steel chosen for its wide use as reference in several IAEA international programmes is JRQ, particularly sensitive to embrittlement.