China Nonferrous Metallurgy

The safe treatment of low and intermediate level radioactive waste remains an unresolved challenge in nuclear energy development, particularly in the case of radioactive strontium, which is readily absorbed by living organisms and accumulates in bone tissue, posing a serious threat to human health. In this study, experiments were conducted using a plasma high-temperature melting engineering prototype for low-level waste, developed by the Southwestern Institute of Physics, to investigate the application of plasma vitrification technology in treating radioactive waste from nuclear power plants, with a specific focus on the stabilization of radioactive strontium (Sr). Experimental results indicate that the prototype system has a processing capacity of approximately 50 kg/h and operates stably under continuous conditions. The temperatures of the primary and secondary combustion chambers were maintained at approximately 727.7℃ and 919.3℃, respectively. Fluctuations in temperature following the introduction of simulated waste were minor and had negligible impact on process stability. In the solidified products, over 60% of Sr was incorporated within the glass matrix, demonstrating effective stabilization. Trace amounts of Sr were detected in the emergency cooling tower wastewater and in the ash collected from the baghouse filter, while particulate matter in the flue gas contained only minimal levels of Sr. Additionally, XPS analysis revealed that Sr within the vitrified product primarily exists in the form of strontium oxide and undecomposed strontium carbonate. These findings provide direct guidance for the practical engineering application of plasma high-temperature melting technology for the treatment of radioactive waste and hold significant scientific and innovative value. With further optimization of process parameters and equipment design, this technology is expected to become one of the effective solutions for treating low- and medium-level radioactive waste.