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Lock-in thermography for characterization of nuclear materials

A simplified procedure of lock-in thermography was developed and applied for characterization of nuclear materials. The possibility of thickness and thermal diffusivity measurements with the accuracy better than 90% was demonstrated with different metals and Zircaloy-4 claddings. | Lock-in thermography for characterization of nuclear materials EPJ Nuclear Sci. Technol. 2 20 2016 Nuclear Sciences A. Semerok et al. published by EDP Sciences 2016 amp Technologies DOI 10.1051 epjn 2016015 Available online at http www.epj-n.org REGULAR ARTICLE Lock-in thermography for characterization of nuclear materials Alexandre Semerok Sang Pham Tu Quoc Guy Cheymol Catherine Gallou Hicham Maskrot and Gilles Moutiers Den-Service d Études Analytiques et de Réactivité des Surfaces SEARS CEA Université Paris-Saclay 91191 Gif-sur-Yvette France Received 23 September 2015 Received in final form 2 February 2016 Accepted 22 February 2016 Published online 15 April 2016 Abstract. A simplified procedure of lock-in thermography was developed and applied for characterization of nuclear materials. The possibility of thickness and thermal diffusivity measurements with the accuracy better than 90 was demonstrated with different metals and Zircaloy-4 claddings. 1 Introduction ΔT Lock-in thermography is a non-destructive method which may be applied to test and to ensure remote control over materials in severe environment e.g. nuclear installations in a wide temperature range. The method is based on the laser heating of a sample with a modulated laser power at a given frequency f Hz followed by measurements of a thermal radiation emitted by the sample. The phase shifts D between the laser power and the thermal radiation measured at different modulated frequencies are then Fig. 1. Phase shift of heating temperature. compared with those obtained with an analytical 3D t model developed at the LISL DEN DANS DPC SEARS In the heating models 1 2 for a surface with a deposited in case of the heating of a sample covered by a deposited layer we supposed that the layer surface thermal resis- layer 1 2 . Thus it is possible to provide a tool to tance gt 1 . By diffusivity deposited layer surface thermal contact resis- applying the Fourier series analysis to the intensity of the tance .