PSI - Issue 14

Ramesh Kumar et al. / Procedia Structural Integrity 14 (2019) 577–583 R. Kumar / Structural Integrity Procedia 00 (2018) 000–000

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22 24 26 28 30 32 34 36 38 40 42 Threshold Bulk Heq (ppm)

r = 0.015 r = 0.05 r =0.13 r = 0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

Fret Depth (mm)

Fig. 3. Threshold bulk Heq for DHC initiation for BPF under normal operation for pressure tube inlet (away from rolled joint)

Fig.3 shows that bounding flaw depth is higher for larger flaw root radius. The minimum bounding flaw depth of 0.54mm with bulk H eq equal to 27ppm is bounding for DHC initiation for root radius equal to 0.015mm near PT inlet.

0.5 0.6 0.7 0.8 0.9 1.0 1.1 40 45 50 55 60 65 70 75 80 85 Threshold Bulk Heq (ppm) Fret Depth (mm) r = 0.015 r = 0.05 r = 0.13 r = 0.3

Fig. 4. Threshold bulk Heq for DHC initiation for BPF under normal operation for pressure tube outlet (away from rolled joint)

Fig.4 shows that bounding flaw depth is higher for larger flaw root radius. The minimum bounding flaw depth of 0.57mm with bulk H eq equal to 50ppm is bounding for DHC initiation for root radius equal to 0.015mm near PT outlet.