Removal of dissolved 85Kr by vacuum degassing method.

In the irradiation apparatus where unsealed 85Kr gas is used as an internal radiation source for liquid-phase chemical reaction, the 85Kr gas dissolved in a liquid reactant must be removed after irradiation. Experiments on removal of dissolved 85Kr by the vacuum degassing method were carried out to examine the influence of degassing temperature, initial 85Kr concentration and stirring of a solution on the removal. The liquid reactant used was a water of 500 ml in which 85Kr gas was dissolved. The removal effect became greater with increasing temperature. The dissolved 85Kr concentration after removal decreased exponentially with the reciprocal of degassing temperature. Further, the removal effect was intensely affected by stirring of the solution and was independent of the initial 85Kr concentration. The removal factor of dissolved 85Kr at 33 degrees C reached 5 X 10(3) after a 30 minute lapse.