Physico–statistical models based on the residual defectiveness of structural materials - Probabilistic Safety Assessment for Optimum Nuclear Power Plant Life Management (PLiM) - page 122

5.3 Dependence of the number of defects on their size before
flaw inspection (1) and after testing and repair (2).
5.4 Defects detected in inspection.
￿ ￿ ￿ ￿ ￿
5.5 Initial defectiveness (1), defects detected at 100% detectability
of inspection (2) and residual defectiveness (3).
Unfortunately, in most cases, and possibly in all cases, the inspection
using NDT methods does not achiev 100% reliability of quality control.