Study on Pb-Bi Corrosion of Structural and Fuel Cladding Materials for Nuclear Applications (2) -Part I. Stability of Oxide Layer Formed on High-Chromium Steels in LBE under Oxygen Content and Temperature Fluctuation-

Mller, G.*; Schumacher, G.*; Heinzel, A.*; Weisenburger, A.*; Zimmermann, F.*; Furukawa, Tomohiro  ; Aoto, Kazumi 

The behaviour of protective oxide layers on P122 and its welds and of ODS steel is examined under conditions of fluctuating temperatures and oxygen concentrations to simulate hot spot and loss of oxygen control. P122 steel (12Cr) and its welded joints are exposed to LBE at 550C for 4000h with oxygen concentrations changing between 10 and 10wt% every 800h. It is found that like in case of constant oxygen concentration of 10wt% a protective spinel layer was maintained on P122 and also on its welded joint. Experiments with fluctuating temperatures from 550C to 650C and back every 800h yield satisfying corrosion protection up to 4800h only for the GESA treated ODS steel in LBE with 10wt%. Original ODS steel in LBE with 10 and 10wt% oxygen showed local strong dissolution attack after 4800h in agreement with the behaviour of ODS in LBE with a constant temperature of 650C. GESA treated ODS steel does not form stable protective alumina layers under condition of fluctuating temperatures in LBE with 10wt% oxygen.