DYNAMIC ION-EXCHANGE CHROMATOGRAPHY FOR THE DETERMINATION OF NUMBER OF FISSIONS IN URANIUM-DIOXIDE FUELS

The liquid chromatographic determination of the fission monitor **1**3**9La has been examined for the determination of the number of fissions and burnup in UO//2 fuels. Lanthanum was separated from the fuel and other fission products on a reversed phase dynamically modified with 1-octanesulfonate, and eluted metal ions were detected after an 'on-line' postcolumn reaction with Arsenazo III. The relative standard deviation for lanthanum determinations done over a 2-week period was 0. 6%. The agreement between the chromatographic procedure and standard mass spectrometric procedures using **1**4**5** plus **1**4**6Nd as a fission monitor was within approximately 2%; the majority of this 2% difference was attributed to uncertainties in the accepted values for fission yields.