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Metal surface cleaning is highly required in different fields of modern industry. Nuclear industry seeks for new methods for oxidized surface decontamination, and thermonuclear installations require the cleaning of plasma facing components from tritium-containing deposited layer. The laser ablation is proposed as an effective and safe method for metal surface cleaning and decontamination. The important factor influencing the laser heating and ablation is the in-depth distribution of laser radiation. The model of light propagation in a scattering layer on a metal substrate is developed and applied to analyse the features of light distribution. To simulate the contaminated surfaces, the stainless steel AISI 304L was oxidized by laser and in a furnace. Radioactive contamination of the oxide layer was simulated by introducing europium and/or sodium. The decontamination factor of more than 300 was demonstrated with found optimal cleaning regime. The decreasing of the corrosion resistance was found after laser cleaning. The ablation thresholds of ITER-like surfaces were measured. The cleaning productivity of 0.07 m2/hour∙W was found. For mirror surfaces, the damage thresholds were determined to avoid damage during laser cleaning. The possibility to restore reflectivity after thin carbon layer deposition was demonstrated. The perspectives of further development of laser cleaning are discussed.

Le nettoyage des surfaces métalliques est nécessaire dans différents domaines de l'industrie moderne. L'industrie nucléaire cherche de nouvelles méthodes de décontamination des surfaces oxydées, et les installations thermonucléaires nécessitent le nettoyage des composants face au plasma pour enlever la couche déposée contenant tritium. L'ablation laser est proposée comme une méthode efficace et sûre pour le nettoyage des surfaces métalliques et leur décontamination. Le facteur important influençant le chauffage et l'ablation laser est la distribution en profondeur de l’intensité laser. Le modèle de propagation de la lumière dans une couche diffusant sur un substrat métallique est développé et appliqué pour analyser les caractéristiques de distribution de lumière. Pour simuler les surfaces contaminées, l'inox AISI 304L a été oxydé par laser et chauffé dans un four. La contamination radioactive de la couche d'oxyde a été simulée par l'introduction d’europium et / ou de sodium. Un facteur de décontamination de plus de 300 a été démontré avec le régime de nettoyage optimal trouvé. Une diminution de la résistance à la corrosion a aussi été montrée après un nettoyage laser. Les seuils d'ablation des surfaces ITER-like (représentatives d’ITER) ont été mesurés. Une vitesse de nettoyage de 0,07 m2/W∙h a été trouvée. Pour les surfaces miroir, les seuils de dommages étaient déterminés pour éviter les dommages lors du nettoyage au laser. La possibilité de restaurer la réflectivité après le dépôt d’une couche mince de carbone a été démontrée. Les perspectives de développement ultérieur de nettoyage laser sont discutées. / Metal surface cleaning is highly required in different fields of modern industry. Nuclear industry seeks for new methods for oxidized surface decontamination, and thermonuclear installations require the cleaning of plasma facing components from tritium-containing deposited layer. The laser ablation is proposed as an effective and safe method for metal surface cleaning and decontamination. The important factor influencing the laser heating and ablation is the in-depth distribution of laser radiation. The model of light propagation in a scattering layer on a metal substrate is developed and applied to analyse the features of light distribution. To simulate the contaminated surfaces, the stainless steel AISI 304L was oxidized by laser and in a furnace. Radioactive contamination of the oxide layer was simulated by introducing europium and/or sodium. The decontamination factor of more than 300 was demonstrated with found optimal cleaning regime. The decreasing of the corrosion resistance was found after laser cleaning. The ablation thresholds of ITER-like surfaces were measured. The cleaning productivity of 0.07 m2/hour∙W was found. For mirror surfaces, the damage thresholds were determined to avoid damage during laser cleaning. The possibility to restore reflectivity after thin carbon layer deposition was demonstrated. The perspectives of further development of laser cleaning are discussed.