Physico–statistical models based on the residual defectiveness of structural materials - Probabilistic Safety Assessment for Optimum Nuclear Power Plant Life Management (PLiM) - page 120

DN550 DN750 DN1100

DN25 DN100 DN250

Welding method

DN25 DN100

DN250

DN750

DN550

DN1100

Welding method

5.1 Diagrams of specific defects in welds in steam generator
casings (I-III) and nozzle welds (IV) under different types of welding
ised: I, II - respectively, electroslag, automatic submerged arc; III,
IV - manual electric welding.

￿ ￿ ￿ ￿ ￿

In conducting successful hydraulic tests, if an a cr < s , the dependence
N (a) corresponds to that shown Fig. 5.2c.
The dependence N ( a ) also affects repair according to the results of flaw
inspection (Fig. 5.3). The value a 0 in Fig. 5.3 corresponds to the rejection
size of the defect.
The curves N ( a ) (see Fig. 5.2) can be called curves that characterise real
defects in a construction. Curve 2 in Fig. 5.3 corresponds to the residual
defectiveness remaining in the structure after inspection and repair of real
defects. For brevity, the term 'residual real defectiveness after inspection
and repair' will be replaced by the term 'residual defectiveness'.
The actual initial (prior to inspection) defectiveness and residual
defectiveness should distinguish between themselves and also should be