Leaching properties of Cs-134 from spent ion exchange resins solidified in cement-biochar matrix

The leaching properties of Cs-134 from spent ion exchange resins solidified in cement-biochar matrix were investigated. The leaching test was conducted according to ANSI/ANS 16.1 method. The leachants used in this experiment were rainwater, groundwater and seawater. After each leach period, the activity of Cs-134 was measured using gamma spectrometry. Based on all the experimental data, the cumulative leach fraction and leachability index were calculated. The compressive strength test of the cement-biochar-spent resins matrices after 90 days of leaching test were also measured. The result showed that the release of Cs-134 from the cement-biochar-spent resins matrices in rainwater, groundwater and seawater were found lower than their control specimen (without biochar). The leachability indices of Cs-134 were found acceptable (i.e. 6) for solidified radioactive waste. It was also observed that the compressive strengths were increased after the leaching test. Thus, this study has shown that the presence of biochar in cement matrix may play a role in retained the Cs-134 in the waste form.