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Analysis of Magnetic Nondestructive Measurement Methods for Determination of the Degradation of Reactor Pressure Vessel Steel

: Vértesy, Gábor; Gasparics, Antal; Szenthe, Ildikó; Rabung, Madalina; Kopp, Melanie; Griffin, James. M.

Fulltext ()

Materials 14 (2021), No.18, Art. 5256, 15 pp.
ISSN: 1996-1944
European Commission EC
H2020; 755330; NOMAD
Nondestructive Evaluation System for the Inspection of Operation-Induced Material Degradation in Nuclear Power Plants
Journal Article, Electronic Publication
Fraunhofer IZFP ()
magnetic nondestructive evaluation; reactor pressure vessel; neutron irradiation embrittlement; magnetic adaptive testing; micromagnetic multiparameter microstructure and stress analysis 3MA; Barkhausen noise measurement; steel degradation; ductile to brittle transition temperature

Nondestructive magnetic measurement methods can be successfully applied to determine the embrittlement of nuclear pressure vessel steel caused by neutron irradiation. It was found in previous works that reasonable correlation could be obtained between the nondestructively measured magnetic parameters and destructively determined ductile-to-brittle transition temperature. However, a large scatter of the measurement points was detected even in the cases of the nonirradiated reference samples. The reason for their scattering was attributed to the local inhomogeneity of material. This conclusion is verified in the present work by applying three different magnetic methods on two sets of Charpy samples made of two different reactor steel materials. It was found that by an optimal magnetic pre-selection of samples, a good, linear correlation can be found between magnetic parameters as well as the ductile-to-brittle transition temperature with low scattering of points. This result shows that neutron irradiation embrittlement depends very much on the local material properties.