Chromatographic decontamination of nitric acid intermediate level waste

The technical feasibility of partitioning concentrated nitric acid intermediate level waste (ILW) solutions arising from the PUREX process into a small high active waste volume and a large low active waste volume by employing chromatographic methods has been demonstrated for 1 L batches. Caesium-134 and -137 were selectively separated with a decontamination factor (DF) greater than 1 x 105 in a newly developed, 'suspended bed' column filled with the microporous inorganic exchanger ammonium molybdatophosphate. Antimony-125 and the actinides/lanthanides with the valence state 3+ were retained with DFs between 40 and 1000, respectively, on oxides of antimony or manganese and on an extraction chromatographic column containing n-octyl(phenyl)-N,N'-di-isobutylcarbamoylmethylphosphine oxide. Ruthenium-106 and cobalt-60 were removed on a column loaded with dimethyl-glyoxime on an organic matrix with DFs greater than 20. For the extrapolation of the quantity of secondary waste arising to the amount that will be created in a 350 t/a reprocessing plant of the Federal Republic of Germany (0.5 m3 ILW/t HM) by the use of chromatographic materials for the decontamination of the ILW, the results obtained in the 1 L batch experiments are taken as a basis, leading to an amount of about 300 kg per year. (author). 14 refs, 1 fig., 4 tabs