The prospect of very long term storage of used nuclear fuel (UNF) in dry cask storage systems (DCSSs) creates potential susceptibility of welded canisters and other components to long term aging mechanisms (e.g. atmospheric SCC). Thus the identification of NDE methods and technologies for detecting flaws in the canister will be essential to ensuring the confinement integrity of welded canisters over the storage period. Although very different requirements will determine the minimum detectable flaw depth in welded canisters for dry storage of UNF compared to class 1 component in LWRs it’s anticipated that knowledge of flaw depth size will still be a critically important piece of information in determining the urgency of performing mitigating actions. Eddy current techniques offer significant advantages over other NDE techniques for performing inspections that target outside surface initiating flaws. This paper will discuss the applicability of eddy current for detection and sizing of flaws in welded canisters and discuss progress on efforts to develop eddy current based techniques for flaw depth sizing.