Application of Austempered Ductile Iron (ADI) in Cask/Containers for Spent Nuclear Fuel

Now-a-days the horizons are expanding. Everyday new opportunities are knocking at the door. The world is standing on its feet to welcome new inventions and discoveries. However, we are going to experience the inexperienced issues ?due to having limited reserves of fossil fuels. In addition to that, the predicament regarding global warming, insufficient output of renewable energy resources, lead our interest in nuclear energy. The vital and challenging issue for this technology is the safe and cost effective geological disposal of radioactive waste and spent fuel. The spent nuclear fuel shipping casks/containers have been an essential part of the nuclear industry’s transportation of radioactive waste materials for decades, that role has been significantly expanded in recent years, especially concerning the dry storage of spent fuel for plant sites around the world. The copper canisters are being used to encapsulate the spent nuclear fuel, consisting of a Ductile Cast Iron insert shielded by an outer thick copper cylinder for corrosion protection. The ductile iron possesses excellent properties such as UTS, YS & Young’s Modulus etc. The work is mainly focused on a special heat treatment named AUSTEMPERING through which; the properties of ductile iron can be enhanced and a promising material, ADI is being developed. Austempered Ductile Iron (ADI) is a ferrous cast material, heat treated by the austempering process resulting in a new material that is strong and tough with a high strength-to- weight ratio. Concisely, the austempering process is an isothermal process which includes austenitization of ductile iron followed by quenching and holding at temperatures in the bainitic range. In properties of high-cycle fatigue; ADIs are superior to the ferritic, pearlitic, or martensitic grades of ductile iron. Due to all this properties, it is considered a very promising engineering material and an economical substitute for wrought or forged steel & ductile iron in several structural applications in the automotive industry. Thus, the main objective of introducing ADI in canisters for nuclear spent fuel, in place of Ductile Iron is to enhance the safety, sustainability as well as the reliability of cask or container for nuclear waste management.