1. VVER Reactor Pressure Vessel Start of life toughness
Open issues

2. SOL toughness - OPEN ISSUES
Existing database
Acceptance of the data: some of the tests were performed more than 30 years ago and validity limits included into the testing standard evolve during these years (notch geometry, pre-cracking procedure, etc.)
Crack arrest toughness
Applicability of Crack Arrest Master Curve is not validated
More data on KIa tests with standard geometry is needed
Material non-homogeneities (forging, welds, etc.)
Modifications of the Master Curve and/or Unified Curve can be applied but more data is needed
Fractographic analysis is recommended to identify fracture type (intergranular, cleavage, ductile tearing)