A study on solidification of CaCO₃ powder containing C-14 by using a low melting glass material

CaCO₃ powder containing C-14, which has a long half-life, is generated from the treatment process of spent activated carbons from the air cleaning system in a nuclear facility, can be decomposed into CaO and CO₂ gas at a temperature above 600 °C. This CaCO₃ must be fabricated into a stable waste form for final disposal at a temperature below 600 °C. In this study, tests on the solidification of CaCO₃ into a waste form were conducted using a bismuth oxide glass with a low melting point. The CaCO₃ was solidified into a homogeneous glass-ceramic waste form with a waste loading of 40 wt% at 460 °C without CaCO₃ decomposition. This waste form had high values of density (3.15 g/cm³) and compressive strength (42.09 MPa), and it was confirmed through leaching tests (ANS 16.1, PCT) that the waste form also had a high chemical durability. (author)