A study on the vitrification test of low level radioactive waste using plasma are melter system

For the research of the vitrification of the low-level radioactive wastes produced from nuclear power plants, one pilot plant with plasma are melter system was built. The tests were done with the surrogate wastes, which were spiked with several metals and were made similar to the real low-level radioactive wastes from nuclear power plants. The steps for the vitrification of the surrogate wastes are follows. First, divide the surrogate wastes as combustible, non-combustible and resin. Second, spike each waste with special materials and melt the waste separately. The offgas was also pick up from special locations in whole system and analyzed. The compound surrogate waste was treated without any spiking materials. Real radioactive materials, Cs and Co were spiked in combustible and non-combustible surrogate wastes. The data from the final products (glasses formulation) were follows. Glass density is 2.42 ∼ 2.95 g/cm3, compressive strength is 30 ∼ 175 Mpa, micro-hardness is 5.5 ∼ 5.8Gpa. The fraction leached for Co is 1.27 x 10-4 ∼ 1.08 x 10-3 and for Cs is 2.46 x 10-3 ∼ 3.23 x 10-2. The leach rate for Co is 4.14 x 10-7 ∼ 5.53 x10-6 g/m2 day and for Cs is 4.58 x 10-5 ∼ 3.87 x 10-4 g/m2 day. In the case of offgas, dioxin and furan is average 0.016 nano gram, CO is about 20ppm, NO2 is about 15ppm and SO2 is about 1.5ppm. All of these values are below the regulation limits for environmental gas emission