Thermochemical Decontamination of Paper Wiper Wastes through Combined Carbonization and Chlorination

Abstract

Chlorination has been used for the thermochemical decontamination of radioactive waste to address the significant amount of waste in nuclear facilities. Control of chlorination conditions is essential to optimize decontamination efficiency, as these conditions significantly influence chemical and physical evolution of target waste. In this study, the feasibility of thermochemical decontamination for reducing the radioactivity of paper wiper waste was investigated. A two-step thermochemical process, comprising low-temperature carbonization and high-temperature chlorination, was suggested to improve the decontamination efficiency. Simulated paper wiper waste contaminated with Cs and Co was treated in a closed system filled with air at 250°C for carbonization as a pretreatment. Subsequently, the partial carbonization product was chlorinated at 700–900°C to remove Cs and Co. Decontamination efficiencies of more than 99% were obtained after the two-step thermochemical process.