Purification of radioactive decontamination liquids from NPP Paks with reactive adsorption and ion exchange processes

Complete text of publication follows. In the Paks Nuclear Power Plant, Hungary, alkaline oxidative (NaOH, KMnO4, H2O), liquids are used for the decontamination of the primary circuit. The decontamination liquid contains 110mAg, 95Nb, 54Mn, 58Co, 60Co, 51Cr, 124Sb radioisotopes, the total radioactivity is between 103 - 104 kBq dm-3 liquid. The decontamination liquid can be cleaned with reactive adsorption (active carbon) and ion-exchange process at elevated temperature (333-368 K) in a multilayered column. The distribution of the radioisotope activity in the liquid and solid phases was investigated during the purification process. After purification, the total radioactivity for 54Mn, 60Co and 110mAg was found in the outlet liquid below 1 kBq dm-3 decontamination factor DF ≅ 103...104. The reactive adsorption system (active carbon, KMnO4, NaOH, H2O) was also studied at elevated temperatures (333-368 K) in batch reactor system and with active carbon column experiments. Mathematical model and a computer program was used for the calculation of breakthrough curves of KMnO4 in active carbon columns at elevated temperatures, at reactive adsorption conditions. (author)