Abstract
The paper presents an exploratory study for non-destructive techniques that can be used to detect and characterize the defects in large ductile cast iron (DCI) containers for geological disposal of spent nuclear fuel. Non-destructive examination of the defects in DCI inserts is necessary to meet its acceptance criteria. The aim of the work was to investigate the ability of film radiography in detection of microstructure defects in DCI inserts in the as-produced state as well as heavily deformed components and subsequent identification of the indications via conventional destructive techniques. Radiography of outer insert walls in the as-produced inserts combined with metallography detected slag inclusions at the inner surfaces of the channels. Numerous cracks were detected in the deformed canister walls. Cracks were initiated at large slag defects in the zone of tensile stresses and ductile tearing was identified as a mechanism of their growth.

Key words
spent nuclear fuel, geological disposal, ductile cast iron, non-destructive testing, radiography

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