Non-destructive evaluation of material state by acoustic, electromagnetic and thermal techniques

MATSUMOTO Eiji, and ABE Masataka

Department of Energy Conversion Science, Kyoto University, Kyoto 606-8501 Japan (matumoto@energy.kyoto-u.ac.jp)

Abstract: This paper considers non-destructive evaluation techniques for integrity of structural materials of nuclear power plants. To increase the safety and reliability of long term operating plants, the exact remaining life of each component should be predicted by estimating material states such as the degree of degradation and mechanical states affecting the remaining life. Mechanical fatigue (for instance, degradation and residual stress) and plastic deformation (e.g. mechanical states) have been considered. Conventional flaw detection techniques cannot be applied to estimate such material states without the apparent geometrical changes. On the other hand, mechanical, electromagnetic or thermal properties of the material may change by several mechanisms. Several NDE techniques are proposed for the purpose and they are acoustic impedance method using phased array transducer, magnetoacoustoelasticity, magnetic flux leakage testing (MFLT), and thermograph combined with magnetic heating. Feasibility of the proposed techniques is discussed by applying them to typical carbon steel specimens.
Keyword: fatigue; plastic deformation; NDE; acoustic impedance; magnetic properties