Corrosion of an India produced RAFM steel in flowing lead-lithium eutectic

Abstract

Reduced Activation Ferritic Martensitic (RAFM) Steel has been specifically developed to serve as a structural material for fusion reactor applications. To establish the corrosion compatibility of an India produced RAFM steel (RAFMS) with Pb-16at.% Li eutectic (Pb-16Li), an electromagnetic pump driven loop has been installed and the compatibility of this RAFMS material has been tested in liquid Pb-16Li at 773K for 5, 000h of exposure at a flow velocity of 0.6–1.5m/s. A corrosion rate of 47–50μm/y was established for the RAFM steel from weight loss measurements and the rate was found to depend on the variation in local flow velocity over the exposed samples. The corrosion attack by liquid Pb-16Li was found to be non uniform in nature which resulted in the formation of undulations over the exposed RAFMS surface. The corrosion mechanism was governed by dissolution of iron and chromium from the RAFMS matrix into the molten Pb-16Li accompanied by enrichment of tungsten near the exposed surface.