Pete used the VIPER program to predict beltline failure frequencies (per vessel year) for typical BWRs. VG3 and 4 are frequency plots and not probability plots.

For VG7 for large Category LOCAs, see big impact with time between 40 and 60 years; attributed to effect of radiation embrittlement; for smaller LOCAs don’t see much effect of time.

EDY stands for Effective Degradation Years; used to normalizes degradation to a reference of a 600oF operating temperature.

For CRDM nozzle ejection probability the assumption in VG11 that immediately have circumferential TWC of 30 degrees is highly conservative according to Bruce in that most are axially oriented.

Of 30 plants, there were 11 nozzles that had circumferential cracks; all of these plants were at about 20 EDY so Pete could take time factor out; total number of nozzles in 30 plants was 881

POD curve for NDE; cracks were EDM notches that were compressed to make them tight; eventually will get some real cracks from the North Anna head that can be used for calibration/validation

VG15 shows the probability of leak in one of 98 nozzles in this plant per vessel year; shows effect of NDE on probability of leakage

VG15 and 16 show effectiveness of NDE and how PFM models can account for inspection in their analyses.

VG17 shows decreasing frequency with time which reflects benefit of inspection.

To get 5,000 gpm (19,000 lpm) leakage, need ejection of 2 nozzles; most likely scenario is for collateral damage as one ejects and causes damage to adjacent nozzles.