PARTITION OF IODINE BETWEEN LIQUID SODIUM AND GAS PHASE AT 500 DEGREES C

Iodine, labelled with 131I, has been added to high purity sodium and the relative volatility has been measured at 500°C in distillation experiments. The effect of oxygen concentration in the sodium has been measured over the range 1 ppm to 104 ppm oxygen. The data at low oxygen concentration can be used to calculate the loss of fission product iodine from the sodium blanket in the case of fuel can failure, core melt down without breaching of the sodium containment, or uncanned fuel operation. The data at high oxygen concentration apply to the case of partial oxidation of the sodium, e.g. due to a sodium fire. The effect of iodine concentration on the relative volatility of the iodine and the sodium has been measured in the concentration range 10-3 ppm to 10-2 ppm of iodine. The effect of increasing the iodine concentration is to decrease the volatility of iodine relative to that of sodium. At the highest iodine concentration studied the iodine is approximately 30 per cent less volatile than at the lowest iodine concentration levels. © 1969.