Kinetics of gas phase oxygen control system (OCS) for stagnant and flowingPb-Bi Systems

Pb and Pb-Bi are known to be very corrosive to structural materials at elev ated temperatures. In recent studies, the necessity of measurement and cont rol of the oxygen concentration in the liquid metal in order to safely oper ate a liquid Pb or Pb-Bi loop has been shown. The dynamic behaviour of the gas phase oxygen control system (OCS), which was developed at Forschungszen trum Karlsruhe (FZK), is investigated with respect to diffusion as the limi ting process of oxygen exchange between the gas phase and the liquid metal. In this paper the development of a physical model for this diffusion proce ss is described and compared to experimental results of a stagnant liquid P b-Bi system. The experimental findings are in very good agreement with the theoretical equations describing the thermodynamic and kinetic behaviour of such a system. Recent investigations in a Pb-Bi loop at the Karlsruhe Lead Laboratory (KALLA) indicate that this gas phase OCS is a promising candida te system for an accelerator-driven subcritical system (ADS). (C) 2001 Else vier Science B.V. All rights reserved.