Nondestructive testing of moisture separator reheater tubing system using Hall sensor array

This paper presents a nondestructive testing system for inspecting the moisture separator reheater (MSR) tubing system in a nuclear power plant. The technique is based on partial saturation eddy current testing in which a Hall sensor array is used to measure the radial component of the electromagnetic field distributed in the tubes. A finned MRS tube of ferritic stainless steel (SS439) with artificial, flat–bottom hole-type defects was used in the experiments. The results show that the proposed system has potential applications in the MSR system or ferromagnetic material tubes in general, which could detect the artificial defects of about 20% of the wall thickness (0.24 mm). Furthermore, the defect volume could be quantitatively evaluated.