Development of Ductile Cast Iron for Spent Fuel Cask Applications Using Fracture Mechanics Principles

The structure-property relations of ductile cast irons (DCIs) with varying Cu content and similar to 1 wt% Ni has been investigated with an emphasis on examining their fracture toughness property towards the development of suitable materials for large volume containers for transport of spent fuel. The detailed microstructural characteristics, hardness, tensile and fracture toughness properties of three DCIs were assessed in as-cast and annealed conditions. Fracture toughness values were determined using both ball indentation (K-BI) and J-integral (KJ(Ic)) tests. The obtained results assist to infer that: (1) the amount of pearlite and nodule count increases with increased amount of Cu, (2) the hardness and strength values increase whereas fracture toughness values marginally decrease with increased Cu content, and (3) the magnitudes of K-BI estimated using a proposed analysis are in good agreement with KJ(Ic) values for the as-cast materials.