Combined Effect of Irradiation, Temperature, and Water Coolant Flow on Corrosion of Zr , Ni–Cr , and Fe–Cr Based Alloys

Abstract

Investigation of the role of irradiation on the corrosion resistance of structural alloys is of vital importance for selection of supercritical watercooled reactor (SCWR) materials. Gamma heating under SCWR conditions, which induces enhancement of radiolysis and corrosion kinetics at interfaces, can be efficiently simulated by electron beam irradiation over a wide range of deposited dose and temperature. The NSC KIPTsited Canada–Ukraine Electron Irradiation Test Facility (CUEITF) still remains the only operating facility capable of in situ irradiation of specimens in a supercritical water (SCW) natural circulation loop. This paper reports the results of postirradiation studies of Zr–1%Nb and Ni–Cr Inconel 690/52MSS alloys after a ~500hlong exposure in the CUEITF in the nearcritical (23.5آ MPa/360–385آ°C) regime. Results of scanning electron microscopy (SEM) studies of the sample microstructure are presented along with those of the electronirradiated loop piping, SS X18H10T. The results of corrosion tests under electronirradiation are correlated to the calculated threedimensional (3D) fields of absorbed dose and temperature and to the reference data obtained inpile for topical materials. The paper also discusses the prospects for the use of the CUEITF facility within a cooperative SCWR program and presents an outlook of the facility development.