Corrosive behavior of structural F82H RAFM steel by LTZO ceramic breeder pebbles

Abstract

ORCID　 0000-0001-8067-8732In this study, corrosion behavior of F82H reduced activation ferritic/martensitic steel (RAFM) by LTZO (Li2+xTiO3+y solid solution with 20 wt% Li2ZrO3) ceramic breeder pebbles was investigated at 773–998 K in an inert sweep gas condition (Ar + 0.1 % H2). Due to vapor gas release from the breeder pebbles and those penetrations, corrosion layer formed on the surface of the F82H steel. Glow discharge optical emission spectroscopy (GD-OES) and X-ray diffraction (XRD) identified the corrosion products as cubic, spinel, and rhombohedral Li–TM–O (TM: transition element in F82H such as Fe, Cr, and Mn). The growth of the corrosion layer thickness followed a parabolic curve at 833 K, yielding apparent diffusion coefficient of D = 6.95 × 10–13 cm2/s. Rapid growth was observed at 993 K after a parabolic growth which could be triggered by failure of the protective layer. A comparative analysis indicates a predominant effect of humidity and oxygen in the sweep gas on the growth rate, while the composition and shape of breeding materials have minor impacts.journal articl