Radioisotopic characterization of the water purification filters of the primary circuit of the IEA-R1 reactor, and eventually released liquid effluents, using radioanalytical separation techniques for the determination of difficult-to-measure radionuclides and scaling factors

Separation radiochemical techniques have been commonly used for the characterization of radioactive waste. However, the determination of alpha, beta and gamma emitting radionuclides by radiochemical analysis in cartridge filter samples used in the water re-treatment process of a pool-type reactor was not previously discussed in the literature. This work aims to establish a method of solubilization for the filters, to identify and quantify the radionuclides present in these wastes, being the Key Nuclides (KN) (⁶⁰Co, ^108mAg, ^110mAg) and especially the Difficult To Measure radionuclides (DTM) (⁶³Ni , ⁹⁰Sr, ²'3⁴U, '2³⁵U, ²³⁸U, ²'3⁸Pu, ²'3⁹ + ²⁴⁰Pu, ²⁴'1Pu, ²⁴¹Am, ²⁴²Cm and ²⁴³ + ²⁴⁴Cm), for later application of the Scaling Factors (SF) method in routine radioactive waste characterization work. The distribution of the radionuclides in the cartridge filter was investigated by determination of gamma-emitting radionuclides and the results obtained were used to calculate the Z-score. The results indicated that all the filters can be considered homogeneous, according to the criteria of homogeneity recommended by the International Atomic Energy Agency (IAEA), and with this it was possible to define the quantity of representative samples to be analyzed. From the analytical data, the correlation between the DTMs and the selected KNs was determined and the SFs were obtained for all the DTMs, except for the ²⁴¹Pu. (author)