Management of carbon dioxide released from spent nuclear fuel through voloxidation

The management of radioactive carbon (C-14) from spent nuclear fuel (SNF) in a voloxidation process is vital to prevent radioactive contamination of the environment. Thus, a double alkali method was applied to absorb the gaseous phase of C-14 (CO 2 ) and to immobilize radioactive carbon into a stable structure. Based on the two-film theory, mass transfer and enhancement factor were evaluated for CO 2 absorption in NaOH solution with regards to the effects of operating conditions such as the solution concentration, CO 2 partial pressure, and gas flow rate on the absorbing performance. The absorption tests were carried out targeting the successful capture of CO 2 released from SNF with a high decontamination factors (DF) more than 10 3 . Causticization with Ca(OH) 2 leads to the immobilization of absorbed carbon into a scalenohedral calcite (CaCO 3 ) crystal, and its stable and nonporous characteristics suggested that calcite is a suitable structure for preparing waste forms stored in a geological repository.