Effect of irradiation on the stability of the corrosion layer produced in EUROFER by contact with lithium ceramics

Abstract This paper is concerned with the identification of the corrosive phase formed on the surface of low-activation steel Eurofer by contact with a ceramic bleeder and the effect of irradiation on the stability of the phase. Tests were carried out at 550°C for 164 hours in a mixture of He/H2O (99.8/0.2 %vol) for simulating the purge gas. The results show an important interaction of the steel with the lithium ceramic breeder. The corrosion layer was characterized by scanning electron microscopy, x-ray diffraction, secondary ion mass spectroscopy and Mossbauer spectroscopy to verify the oxides formed during the corrosion test and the modification of the containing species after being subjected to different doses of ionizing radiation and / or deuterium absorption. The relationship of the different iron states and high energy traps for hydrogen isotopes (deuterium) that could be generated in a corrosion layer during reactor operation was also established. The results indicates that ionizing radiation up to the studied doses (200 MGy) does not produce additional defects to those generated by the transformation of hematite into non-stoichiometric wustite, which is the fundamental compound of the corrosion layer by environmental deuterium.