A NON-EQUILIBRIUM MASS TRANSFER MODEL OF SOLID-PHASE OXYGEN CONTROL IN LEAD-BISMUTH EUTECTIC LOOP

抄録

In the lead-cooled fast reactor, solid-phase oxygen control is recognized as an efficient approach to mitigate the liquid lead-bismuth eutectic (LBE) corrosion on the structural steel materials. The dissolution of solid lead oxide (PbO) particles in the mass exchanger (MX) is the oxygen source to make sure the oxygen concentration in LBE in the reasonable ranges. In this work, a non-equilibrium mass transfer model is developed for the solid-phase oxygen control loop to discuss the oxygen control mechanism. The numerical model was established by the LBE mass, momentum, temperature and oxygen concentration balance equations. The fluid-particle mass transfer coefficient is calculated by the heat-mass analogy theory with the well-known Ranz model of the heat convection in packed bed, which is applied in many related experimental and computational studies. With the simulation results under different conditions, it is found that the oxygen concentration in LBE is enhanced greatly under high operating temperature by higher solubility, higher diffusion coefficient and higher Sherwood number with lower LBE viscosity. Moreover, the effects of inlet velocity and void fraction are much less than the temperature. Present work provides meaningful simulation methods and advices for controlling oxygen concentration in LBE and designing the engineering loop.