The Transport of Fission-Product Cesium from Sodium

The vaporization of fission-product cesium from liquid sodium into flowing inert gases was investigated at 730°K. The cesium release rate was found to depend on both the liquid depth of sodium and the molecular weight of the inert carrier gases. A general release equation is developed by considering diffusion in both the liquid and gas phases. This equation is shown to represent the experimental results very well. The limiting case of maximum extent of release, expressed in terms of fractional fission-product vaporization as a function of the fraction of sodium vaporized, can often be calculated from thermodynamic considerations.