Leaching behavior of boric acid and cobalt from paraffin waste forms

Ninety-day leaching test was performed to investigate the leaching characteristics of paraffin waste forms that had been recently generated in large quantities at Korean nuclear power plants(KNPPs). In the case where mixing weight ratio of boric acid to paraffin was 78/22, which was adopted in concentrate waste drying system(CWDS) of KNPPs, the cumulative fraction leached(CFL) of boric acid and cobalt was about 51% and 61%, respectively. The compressive strengths of waste form before and after the leaching test exhibited 666psi(4.53MPa) and 232psi(1.58MPa), respectively. The CFLs of paraffin waste form were well expressed by diffusion-controlled dissolution model such as Gintsling-Brounshtein kinetics. The internal cross-sectional view of specimen after the test demonstrated the applicability of this unreacted shrinking core model to the leaching analysis of paraffin waste form.