CORROSION IN POLYTHERMAL LOOP SYSTEMS. I. MASS TRANSFER LIMITED BY SURFACE AND INTERFACE RESISTANCES AS COMPARED WITH SODIUM-INCONEL BEHAVIOR

摘要

Corrosion studies of Inconel and similar nickel-base alloys in flowing sodium have shown that considerable quantities of nickel are removed from regions hotter than 1300°F and deposited in cooler regions We have compared the observed nickel mass transfer rates with predictions based on the assumption that diffusion of nickel across the liquid boundary layer at the alloy surface controls the processnFor pumped loops operating in the turbulent flow regime, it was demonstrated analytically that the time transient required to achieve steady-state mass-transfer conditions is relatively short compared with normal loop operating times Based on a calculated film coefficient, the predicted transport of nickel from the hot zone was five times greater than that obtained from measurements of crystal deposits in cold zones. This and other considerations suggest that contributions of film resistances are only partially responsible for corrosion in polythermal loops containing liquid metals.