ETUDE DE L’INFLUENCE DE L’HYDROGENE SUR LA STRUCTURE ET LES PROPRIETES MECANIQUES DES ALLIAGES DE ZIRCONIUM

Abstract

Zirconium alloys are considered as the main materials for gainage nuclear combustible and the conception (construction) of pressure tubes in the power reactors cooled down by a caloporator liquid. This use is due particularly to an excellent resistance to the corrosion and to the large transparency to thermical neutrons which are provided by the different reactions of combustible fission , never the less (however), their use at high temperature has some oxidation problems by the primary circuit water. This oxidation releases the hydrogen that diffuses in the material and precipitates in the form of fragile hydrides of Zirconium leading to modifications of the material mechanical properties. The aim of this work is to study the Zirconium alloys behavior by loading of hydrogen under normal conditions and try to explain the different modifications that cause the rupture (breaking) of gainage material. Microscopic study must be, therefore, performed in order to apprehend this phenomenon of the damage by the hydrogen. The material used in this study is a Zirconium alloy obtained by recycling waste and conform to ASTM norm. The elaboration was performed using an arch oven in a vacuum at COMENA Algiers