METHOD OF TREATING NITRIC ACID RECOVERED FROM SPENT NUCLEAR FUEL REPROCESSING PROCESS.

摘要

The nitric acid recovered from the steps of reprocessing spent nuclear fuel is electrolysed to form NOx on condition that the concentration of HNO3 in the solution of the electrolyte is not less than 5M. The NOx which results therefrom is recycled to the various nuclear fuel reprocessing steps in order to be reused, or to be reduced catalytically by reaction with NH3 to be made harmless and released. The dilute nitric acid from the electrolytic tank is concentrated by distillation, and the nitric acid concentrate is recycled to the tank for another electrolysis. It is preferable to perform the abovementioned electrolysis with circulation of the solution of the electrolyte in the electrolytic tank at a linear speed of 1 m/h and/or by using a cation exchange membrane as separator. The efficiency in terms of current of a cathode for generating NOx is improved. In the case where a separator is used, a high efficiency in terms of current is obtained whatever the speed of circulation.