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

Investigation of the role of irradiation on the corrosion resistance of structural alloys is of vital importance for selection of supercritical water-cooled 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 KIPT-sited Canada–Ukraine Electron Irradiation Test Facility (CU-EITF) 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 ~500-h-long exposure in the CU-EITF in the near-critical (23.5 MPa/360–385°C) regime. Results of scanning electron microscopy (SEM) studies of the sample microstructure are presented along with those of the electron-irradiated loop piping, SS X18H10T. The results of corrosion tests under electron-irradiation are correlated to the calculated three-dimensional (3D) fields of absorbed dose and temperature and to the reference data obtained in-pile for topical materials. The paper also discusses the prospects for the use of the CU-EITF facility within a cooperative SCWR program and presents an outlook of the facility development.