Glassy Wasteforms for Nuclear Waste Immobilization

Abstract

Glassy wasteforms currently being used for high-level radioactive waste (HLW) as well as for low-and intermediate-level radioactive waste (LILW) immobilization are discussed and their most important parameters are examined, along with a brief description of waste vitrification technology currently used worldwide. Recent developments in advanced nuclear wasteforms are described such as polyphase glass composite materials (GCMs) with higher versatility and waste loading. Aqueous performance of glassy materials is analyzed with a detailed analysis of the role of ion exchange and hydrolysis, and performance of irradiated glasses.

Using Vitrification for Sewage Sludge Combustion Ash Disposal

“…Vitrification technology of high-level waste generated in industrial processing of exploited nuclear fuel from light water reactors (pressurized and boiling) has been implemented in France (La Hague), the UK (Sellafield), Japan (Tokai, Rokkashomura), and Russia (RT-1 and RT-2). It is the delivery of a significant amount of thermal energy required to form the amorphous structure, and then rapidly cooling the material [65].…”

“…Melting methods Description References 1 Melting in a crucible furnace A cyclical process waste mixed with fine glass is melted in a crucible that also serves as a tank for the vitreous phase [56] 2 Melting in an induction furnace A continuous process waste mixed with fine glass is melted by induction in steel containers limited durability of the furnace due to corrosion of the tank [68] 3 Resistance melting by Joule A continuous process waste and fine glass are melted in a ceramic crucible using an electric current of high intensity the liquid phase collects on the walls of the crucible, and then is discharged to a separate tank [62] 4 Induction melting in a crucible A continuous process used a water-cooled induction furnace the liquid phase collects on the walls of the ceramic crucible replacing the steel crucible ceramic refractory materials significantly extends the life of the induction furnace [60] 5 Plasma melting The use of very high temperatures disadvantage is the limited lifetime of the plasma-generating torch used in the United States to vitrify contaminated soils [65] 6 Microwave melting A cyclical process melting and collecting the liquid phase takes place in the same container the method is energy-saving as a microwave furnace is small and can be installed at the waste location [69] 7 Volume melting A cyclical process it is used in a large steel vessel lined with refractory material, in which the melting process occurs along with the collection of the liquid phase [70] 8 Induction electrodeless melting Alternative method single melting system in the basic convertor furnace [71] applications in car body structures. Glass microspheres have major advantages in comparison with conventional fillers such as composites of polypropylene and polyamide, including improved resistance to scratches and abrasion.…”

Thermochemistry of phosphate glasses for immobilization of dangerous waste

“…Intensive studies on methods of effective immobilization and storage of radioactive waste by vitrification procedure have been conducted for many years. The vitrification of this waste is considered to be especially effective method [1][2][3][4]. This is process that is based on enclosing the waste in the structure of the glass.…”

“…Certain metals (molybdenum, chromium, vanadium and wolfram) and their oxides exhibit limited solubility in glasses. This is why it is significant to adapt the chemical composition and properties of vitreous materials to the form of the introduced waste, its amount as well as to the technical process of the waste immobilization [1,3,4].…”

“…According to available data, these requirements are met by Al, Fe phosphate glasses [3,4,6], and these glasses were selected for study. It was also decided that mechanical activation of glasses by means of long-term grinding as the method for increasing their reactivity, was to be used.…”