Vitrification of borate waste from nuclear power plant using coal fly ash. (I) Glass formulation development

Borate waste, which is the main liquid waste from daily operation of PWR nuclear power plants, contains a large amount of Na and B. The coal fly ash is a by-product of the coal combustion power plants. The high content of SiO2 and Al2O3 of coal fly ash makes it a desirable glass network former additive; therefore, using the coal fly ash to vitrify the borate waste without other additives is of great interest from the view point of economic and environment. In this paper, we evaluate the suitability for vitrifying borate waste using coal fly ash. Upon to 40 wt% of borate waste oxides could be successfully vitrified. Glass with 30 wt% of borate waste and 70 wt% of fly ash contain no crystals and show good chemical durability and suitable viscosity. The coal fly ash is a promising material for use in the immobilization of borate waste.