Modification of zirconium alloy surface using high intensity pulsed plasma beams

摘要

Purpose: The aim of the research was to identify possibility of extending the life time of zirconium claddings. Materials used in nuclear reactors work in extremely hard conditions: irradiation, corrosion, stress. Zirconium alloys, due to their good water corrosion and radiation resistance at normal working conditions of nuclear reactors are used as cladding material for fuel elements. In the case of loss-of-coolant accident (LOCA), the extremely fast oxidation of zirconium at steam or air/steam mixture at temperatures above 800°C results in intense hydrogen generation and possible hydrogen-oxide mixture explosion. The development of the solution to minimize the risk of the accidents mentioned above is urgently needed. The concept of Accident Tolerant Materials (ATM) has been developed recently.Design/methodology/approach: Zirconium surface were treated with 30 high intensity pulsed plasma beams (HIPPB) Cr+Ar, Y+Ar or Al+Ar, with energy density of 4.0 J/cm~2. Oxidation tests: autoclave (water, 360°C, 19.50 MPa) for 7 and 40 days and oven (700°C and 800°C/1000 s/air) followed by cooling in water were performed. Samples were characterised with: SEMs, EDS and GXRD.Findings: Zirconium samples with modified surface layer showed the higher resistance for oxidation in simulated conditions of normal work of PWR reactor and in elevated temperatures. Originality/value: Carried out work was connected with new concept of development accident tolerant materials - ATM.