In-Situ Proton Irradiation-Corrosion Study of ATF Candidate Alloys in Simulated PWR Primary Water

Irradiation enhanced corrosionCorrosion behavior of Accident Tolerant Fuel candidate alloys T91 and Fe15Cr4Al were evaluated using in-situ proton irradiation-corrosion experiments in hydrogenated pure water (at 320 °C, 3 wppm H₂) with a 5.4 MeV protonProton beam. The thin sample acted as a “window” to allow protons to fully penetrate the sample while maintaining system pressure. The area of the samples exposed to the proton beam experienced effects from displacement damage and radiolysis products. The aim of the study was to characterize the effect of radiation on the kinetics and character of oxidation caused by accelerated waterside corrosion under irradiationIrradiation. Samples irradiated with protons for total displacement damage of ~0.1 dpa (dose rate in water, 400 kGy/s) at an exposure time of 24 h were compared. Oxide morphology, phase structure, and composition of the oxide, metal and the metal/oxide interface were investigated using TEM and EDS and are related to the test conditions. The oxidation rate or resulting oxide thickness is dependent on the alloy Cr content; the oxidation rate increased as the Cr content decreased. The resulting oxide consists of an inner layer of Cr-rich spinel oxide and outer magnetite crystals in the unirradiated region; while the irradiated region consists of Cr-rich inner oxide spinel that was partially dissolved and coverage of outer non-faceted hematite precipitates.