CORRELATION WITH COBALT-60 FOR RADIOACTIVE NUCLIDES IN SOLID WASTE GENERATED AT FUKUSHIMA DAIICHI NPS

Abstract

The radioactive nuclides dispersed without control to on- and off-site of Fukushima Daiichi nuclear power station (F1NPS) at its accident in 2011. A large amount of radioactive solid waste has been generated during its decommissioning. Radioactivity inventory of the solid waste should be estimated for R&Ds on waste management. Cobalt-60 is often selected as a key-nuclide for determining activity in solid waste generated at nuclear power plant, and is also detected in various F1NPS waste. In this study, radiochemical analysis data opened to public was investigated for correlation between Co-60 and nuclides of activation and fission products as well as actinides (H-3, C-14, Ni-63, Sr-90, Tc-99, I-129, Cs-137, Eu-154, Am-241, Pu-239+240). Cobalt-60 well correlated with Ni-63, Eu-154, Am-241 and Pu-239+240 in spite of differences in physical/chemical properties and process of contamination. This finding suggests a possibility to apply Co-60 as a key-nuclide of scaling factor method.