Behavior of Radionuclides on Ion‐Exchange Resins

Abstract

This article discusses a study of the behavior of radionuclides on ion exchange resins used for the decontamination of cooling water in a nuclear reactor. The principal objectives of the investigation were identification of the nuclides, measurement of their relative concentration as a function of bed depth, and interpretation of these data in the light of the effective performance of the system. Results showed that, in the cation, anion, and mixed‐bed columns, the concentration of radionuclides on the resin decreased with increasing bed depth. At the same time, the overall half‐life of the retained materials simultaneously increased. As anticipated, considerable variation with depth was observed in relative radionuclide composition, the shorter‐lived materials predominating near the surface, the longer‐lived near the bottom of each column. The data emphasize the care required in using data on gross radioactivity removals for the evaluation of the efficiency of an ion exchange system. This is true because the effluent, although exhibiting a “satisfactory” reduction in gross activity, may actually contain a significantly greater proportion, as well as actual concentration, of longer lived radionuclides.