Davis-Besse Small Bore Class 1 Piping Socket Weld Destructive Examination

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2 Davis-Besse Small Bore Class 1 Piping Socket Weld Destructive Examination Authors: Ryan Hosler (AREVA) Beverly Cyrus (AREVA) Steve Fyfitch (AREVA); Presenter Trent Henline (FENOC)

3 Introduction Davis-Besse LRA includes a requirement to volumetrically or destructively examine (DE) welds (that have been exempted due to size by ASME XI) as a result of age-related OE Weld selection was based on SCC susceptibility Highest temperature Dead legs (stagnant) DE was selected because each DE counts as two NDE in the LR AMP 42 of the most susceptible welds were being removed due to SG replacement 15 of those welds were chosen as a representative sample to satisfy the LR AMP requirements for socket welds Steve Fyfitch August p.3

4 Locations Examined: SG Channel Head Drain Lines SG 1-1 Drain Line SG 1-2 Drain Line Steve Fyfitch August p.4

5 Locations Examined: Hot Leg High Point Vent Lines HL HPV Lines at SG 1-1 HL HPV Lines at SG 1-2 Steve Fyfitch August p.5

6 General Sectioning Plan Mount/Polish/Etch 0 Face Mount/Polish/Etch 90 Face Mount/Polish/Etch 270 Face Mount/Polish/Etch 180 Face Steve Fyfitch August p.6

7 Weld Socket Weld Gap Gap Steve Fyfitch August p.7

8 0 Face SG 1-1 Drain Line Weld 7 8x 900x 180 Face 8x 50x Steve Fyfitch August p.8

9 SG 1-1 Drain Line Weld 8 (270 Face of 8-A2) 8x Steve Fyfitch August p.9

10 SG 1-1 Drain Line Weld 8 (270 Face of 8-A2) 25x Steve Fyfitch August p x

11 SG 1-1 Drain Line Weld 8 (270 Face of 8-A1a) 8x Steve Fyfitch August p.11

12 SG 1-1 Drain Line Weld 8 (270 Face of 8-A1a) 50x Steve Fyfitch August p.12

13 SG 1-2 Drain Line Weld 23 8x Steve Fyfitch August p.13

14 SG 1-2 Drain Line Weld 23 Steve Fyfitch August p.14

15 SG 1-2 Drain Line Weld 24 (180 Face) 8x Steve Fyfitch August p.15

16 SG 1-2 Drain Line Weld 24 (180 Face) 200x 8x 500x Steve Fyfitch August p.16

17 SG 1-2 Drain Line Weld 24 (270 Face) 8x 8x Steve Fyfitch August p.17

18 SG 1-2 Drain Line Weld 24 (270 Face) 500x 200x 8x 600x Steve Fyfitch August p.18

19 SG 1-1 HL HPV Line Weld 3C 8x Steve Fyfitch August p.19

20 SG 1-1 HL HPV Line Weld 3C 200x 1500x Steve Fyfitch August p.20

21 1-5% TW gap 40-65% TW gap Summary of Results: SG Channel Head Drain Lines 40-50% TW gap 20-35% TW gap No Flaw gap SG 1-1 Drain Line No Flaw gap SG 1-2 Drain Line 1-5% OD gap Steve Fyfitch August p.21

22 No Flaw gap No Flaw No gap Summary of Results: Hot Leg High Point Vent Lines No Flaw gap 1-5% TW No gap No Flaw gap HL HPV Lines at SG 1-1 No Flaw gap No Flaw gap No Flaw No gap HL HPV Lines at SG 1-2 Steve Fyfitch August p.22

23 Conclusions Cracking originating at or near the weld root was observed in 5 of the 15 socket welds examined Flaws indicative of TGSCC with some IGSCC and IGA Three synergistic requirements of SCC met (consistent with laboratory testing and operating experience) Susceptible Material Austenitic stainless steel (Type 316 and 308/308L) Aggressive Environment Stagnant water can accumulate elevated levels of dissolved O 2 and Cl, which can be exacerbated at the weld root by the crevice created by the socket weld geometry Temperature likely >200 F at locations of indications due to proximity to SG/HL Sustained Tensile Stress Socket weld geometry creates a stress concentration at the weld root Steve Fyfitch August p.23

24 Questions? Steve Fyfitch August p.24

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