Abstract
The acceptance criteria for the canisters for geological disposal of spent nuclear fuel require non-destructive examination (NDE) to check the presence of technological defects.
This work is devoted to the investigation of the ability of digital radiography compared to conventional film radiography, to detect defects in ductile cast iron (DCI) insert walls in the Swedish canister concept KBS-3. The advantages of digital radiography include at least three times shorter total examination times, significantly wider dynamic range of the optical densities and possibility for automatic detection of the defects larger than 4 mm. Although its resolution is lower than that of film radiography, it is sufficient with large margin for the detection of the defects in DCI inserts. The total time for the insert inspection using digital radiography with some additional measures can be reduced to 24 h. However, faster automated inspection method, e.g. radioscopy, is desirable for large-scale insert inspection.

Key words
spent nuclear fuel, geological disposal, ductile cast iron, film radiography, digital radiography

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