Remote Thermoelastic Characterization of Candidate Structural and Protective Coatings for Lead-Bismuth Eutectic Cooled Nuclear Reactors

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  • KUL - Katholieke Universiteit Leuven

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laser ultrasonics approach to remotely characterize the elastic and thermal properties of a coating-substrate structure, used to protect fuel claddings in lead-bismuth eutectic cooled nuclear reactors, is presented and validated with experimental results. A transient grating geometry is used for multiple wavelength excitation of thermoelastic displacements, and laser beam deflection for detection. The value of Young’s modulus of the coating layer as calculated from the coating’s Rayleigh velocity of 190 50 GPa is in accordance with a nano-indentation measurement. Using a priori knowledge concerning the density and elastic parameters of the coating and substrate, scanning the sample allows the obtaining of a coating thickness map in a fully remote, all-optical way, with an accuracy of about 4 microns for a coating of around 20-micron average thickness. Analyzing the transient thermal grating decay yields a thermal diffusivity value of (5.0 1.6) 10蚠6 m2/s, in the range of low-carbon steels. The consistency of the results infers that the all-optical laser ultrasonics approach should be feasible for remote inspection of the quality of optically rough coated claddings in the harsh environment of a nuclear reactor


Original languageEnglish
Article number915
Pages (from-to)1-21
Number of pages21
JournalApplied Sciences
Issue number5
Publication statusPublished - 4 Mar 2019


  • non-destructive testing, remote characterization, lead-bismuth cooling, elastic characterization, thermal characterization, laser ultrasonics, coating characterization, fuel cladding

ID: 5038137