Update on SCC CGR testing of Alloy 690(non cold-worked conditions)

Work sponsored by the US Nuclear Regulatory Commission

Bogdan Alexandreanu, Yiren Chen, Ken Natesan and Bill Shack

Argonne National Laboratory

NRC Project Manager: Greg Oberson

Alloy 690 Expert Panel Meeting

Tampa, FL

December 2-5, 2014

Work sponsored by the US Nuclear Regulatory Commission 2

Presentation Outline

Background and experimental approach

Results:- Alloy 690 MA in plate form - Alloy 690 TT CRDM (Valinox, Sumitomo)

Summary

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Cyclic response – Alloy 690 in the CW and the as-received conditions

Alloy 690 26% cold work: environmental enhancement as high as D-B nozzle #3 Alloy 690 26% cold work: environmental enhancement much higher than as-received condition

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10-11 10-10 10-9 10-8 10-7

1/2-T CT DB N3CC-31/4-T CT DB N3CL-1A690WC-SL-1A690WC-ST-1

CG

Ren

v (m

/s)

CGRair (m/s)

Alloy 690 and Davis-Besse N#3 Alloy 600Simulated PWR Water

Best-Fit Curve for Davis-Besse N#3 A600CGRair + 6.6 x 10–7(CGRair)

0.33

10-12

10-11

10-10

10-9

10-8

10-7

10-12 10-11 10-10 10-9 10-8 10-7

26% CR, A690WC-SL-126% CR, A690WC-ST-1C690-CR-1C690-LR-2

CG

Ren

v (m/s

)CGRair (m/s)

Alloy 690Simulated PWR Water at 320°C

Best-Fit Curve for Alloy 600CGRair + 4.4 x 10–7(CGRair)

0.33

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SCC response of non cold-worked Alloy 690 and 690HAZ

Alloy 690 very low SCC CGRs Alloy 690HAZ SCC CGRs are perhaps slightly higher

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10 15 20 25 30 35 40 45 50

C690-LR-2C690-CR-1HAZ, CF690-CR-1HAZ, CF690-CR-3

Expe

rimen

tal C

GR

(m/s

)

Stress Intensity K (MPa·m1/2)

Alloy 690 and 690 HAZSimulated PWR environment320°C

MRP-55Alloy 600

75 Percentile

Solid symbols: CL

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Fracture surface of non cold-worked Alloy 690

Facets (TG) and, occasionally, striations (environmental fatigue)

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SCC response of non cold-worked Alloy 690

Unlike the alloy in the as-received condition, the HAZ shows some IG

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Bill Mills et al (Env Deg 2009)

Bill Mills reports “substantial” IG engagement: 9% for tR= 30s, and 20% for tR= 600s under continuous cyclic at ∆K = 12 MPa m1/2 in DPW at 288ºC

No IG engagement for ∆K > 16 MPa m1/2

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Corrosion fatigue work by Bill Mills et al (Env Deg 2009)

Bettis data show higher enhancement than ANL DPW (<5 ppb) ANL DPW (<5 ppb data) were all obtained with short rise times, tR = 12 seconds

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Excellent agreement between current ANL data (solid blue) and Bettis data (red) on time domain plots (left plot)

Corrosion fatigue work by Bill Mills et al (Env Deg 2009)

10-9

10-8

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10-6

10-5

10-9 10-8 10-7 10-6 10-5

C690-CR-1

C690-LR-2

Alloy 690Simulated PWR Water at 320°C

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Experimental Approach

1.0

2.0

3.0

4.0

5.0

6.0

7.0

5 10 15 20 25

C690-LR-2C690-CR-1

Alloy 690Simulated PWR Water at 320°C

CG

Ren

v/CG

Rai

r

K (MPa·m 1/2)

BM

Opt

imum

IG

BM

No

IG

Bill Mills “optimum”: ∆K = 12 MPa m1/2 , tR= 600s (da/dN = 5E-8 m/s), GGRenv/CGRair ~ 6 No IG engagement for ∆K > 16 MPa m1/2

R=0.5, 600/12 (∆K = 14-15 MPa m1/2) was used extensively at ANL for transitioning; for welds at 320ºC, da/dN = 3.8E-8 m/s

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Alloy 690 Plate (Heat NX3297HK12)

Tested and cracked at ANL in 2005-2006 in 26% cold-rolled condition Subsequently tested worldwide Also known as “ANL plate” or “rogue heat” (J. Hickling)

A690WC-AR-SL-5(5 mm from surface)

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Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

Heat NX3297HK12 very resistant to fatigue (as resistant as Alloy 600) Environmental enhancement is minimal

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CGR air 600 (NUREG-6721)CGR env 600 (NUREG-4667)Alloy 690 AR (A690WC-AR-SL-5)

CG

Ren

v (m

/s)

CGRair (m/s)

Alloy 690 Heat NX3297HK12Simulated PWR Water at 320°C Best-Fit Curve for Alloy 600CGRair + 4.4 x 10–7(CGRair)

0.33

R=0.1

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1.0

2.0

3.0

4.0

5.0

6.0

7.0

5 10 15 20 25

A690WC-AR-CL-5C690-LR-2C690-CR-1

Alloy 690Simulated PWR Water at 320°C

CG

Ren

v/C

GR

air

K (MPa·m1/2)

BM O

ptim

um IG

BM N

o IG

12

3

4

5

CGRair = ct. (3E-11 m/s) da/dN < 2E-8 m/cycle (BM = 5E-8 m/cycle) Environmental enhancement is minimal (less than the Valinox CRDM in

LR orientation) and flat (does not seem to show the ∆K dependence)

Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

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28.400

28.450

28.500

28.550

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55

60

65

70

75

80

4800 4900 5000 5100 5200 5300 5400 5500 5600Time (h)

Specimen A690WC-AR-SL-5PWR environment

Cra

ck L

engt

h (m

m)

Km

ax (M

Pa

m0.

5 )

Kmax

Crack Length

Period 301.1 x 10–11 m/s51.2 MPa m0.5

R=0.7., 1200/12 + 2h

P30: Response from cycle + hold is at the air line (1.04E-11), SCC CGR component is “zero”.

Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

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P31: “No growth” condition confirmed at constant load The “rogue heat” did not live up to its reputations or SCC in a cold-worked

condition is not a good predictor for the SCC behavior of the as-received alloy

28.460

28.480

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28.520

28.540

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55

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80

5400 5600 5800 6000 6200 6400 6600 6800Time (h)

Specimen A690WC-AR-SL-5PWR environment

Cra

ck L

engt

h (m

m)

Km

ax (M

Pa

m0.

5 )

Kmax

Crack Length

Period 31no growth

51.5 MPa m0.5

Constant load

Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

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Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

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Last region on the test, TG cracking

Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

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TG cracking, cracked inclusions

Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

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Some smooth facets, perhaps some IG (not unambiguous)

Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

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Some smooth facets, perhaps some IG (not unambiguous)

Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

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Striations (environmental fatigue), perhaps some IG (not unambiguous)

Alloy 690 Plate (Heat NX3297HK12): Specimen A690WC-AR-SL-5

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Alloy 690 CRDM (Sumitomo): Specimen S690-CR-1

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Alloy 690 AR CRDM (C690-CR-1)

Alloy 690 AR CRDM (S690-CR-1)

CG

Ren

v (m

/s)

CGRair (m/s)

Alloy 690 CRDMSimulated PWR Water at 320°C

Best-Fit Curve for Alloy 600CGRair + 4.4 x 10–7(CGRair)

0.33

Identical fatigue and corrosion fatigue response to that of the ValinoxCRDM

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1.0

2.0

3.0

4.0

5.0

6.0

7.0

5 10 15 20 25

A690WC-AR-CL-5C690-LR-2C690-CR-1S690-CR-1

Alloy 690Simulated PWR Water at 320°C

CG

Ren

v/C

GR

air

K (MPa·m1/2)

BM O

ptim

um IG

BM N

o IG

45

6

7

16

Alloy 690 CRDM (Sumitomo): Specimen S690-CR-1

CGRair = ct. (3E-12 m/s) da/dN < 2E-8 m/cycle (BM = 5E-8 m/cycle) Environmental enhancement shows max at ∆K = 12 MPa m1/2

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Alloy 690 CRDM (Sumitomo): Specimen S690-CR-1

P19: Environmental enhancement was not maintained when the 4h hold was introduced

P19: Response from cycle + hold is at the air line (1.04E-11), SCC CGR component is “zero”

P20: Confirmed at constant load

14.510

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14.560

14.570

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40

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100

5000 5500 6000 6500Time (h)

Specimen S690-CR-1PWR environment

Cra

ck L

engt

h (m

m)

K max

(MPa

m0.

5 )

Period 20no growth

34.7 MPa m0.5

Constant load

Kmax

Crack Length

Period 191.34 x 10–12 m/s34.7 MPa m0.5

R=0.63, 7000/12 + 4h

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Alloy 690 CRDM (Sumitomo): Specimen S690-CR-1

Initial CF testing, low enhancement No IG cracking, some off-plane growth

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Alloy 690 CRDM (Sumitomo): Specimen S690-CR-1

Final CF testing, high enhancement Striations No (unambiguous) IG cracking

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Alloy 690 CRDM (Sumitomo): Specimen S690-CR-1

Final CF testing, high enhancement Striations No IG cracking

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Alloy 690 MA plate (Allvac): Specimen B25K

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10-12 10-11 10-10 10-9 10-8 10-7

Alloy 690 AR (B25K)Alloy 690 AR (A690WC-AR-SL-5)

CG

Ren

v (m/s

)

CGRair (m/s)

Alloy 690 PlateSimulated PWR Water at 320°C Best-Fit Curve for Alloy 600CGRair + 4.4 x 10–7(CGRair)

0.33

R=0.1

CGRair = ct. (3E-12 m/s) da/dN < 3E-8 m/cycle (BM = 5E-8 m/cycle) Environmental enhancement shows max at ∆K = 12 MPa m1/2

Work sponsored by the US Nuclear Regulatory Commission 29

1.0

2.0

3.0

4.0

5.0

6.0

7.0

5 10 15 20 25

C690-LR-2C690-CR-1A690WC-AR-CL-5S690-CR-1B25K

Alloy 690Simulated PWR Water at 320°C

CG

Ren

v/C

GR

air

K (MPa·m1/2)

BM O

ptim

um IG

BM N

o IG

45

6

7

16

34

56

7

CGRair = ct. (3E-12 m/s) da/dN < 3E-8 m/cycle (BM = 5E-8 m/cycle) Environmental enhancement builds-up eventually reaching that observed

for CRDM materials (∆K = 12 MPa m1/2)

Alloy 690 MA plate (Allvac): Specimen B25K

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Experimental approach

30

Alternating hold between Kmin and Kmax = turns SCC “off” and “on” SCC CGR = difference between the two rates Maintain cycling longer

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Maintain cycling for longer periods of time Environmental enhancement was maintained (unlike the S690 CRDM) SCC CGR = difference between the two rates = 1E-12 m/s

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19.350

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25

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35

40

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50

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60

2000 2500 3000 3500 4000Time (h)

Specimen B25KPWR environment

Cra

ck L

engt

h (m

m)

K max

(MP

a m

0.5 )

Kmax

Crack Length

Period 86.20 x 10–12 m/s35.0 MPa m0.5

R=0.63, 6000/12 + 4h at Kmin

Period 97.3 x 10–12 m/s35.0 MPa m0.5

R=0.63, 6000/12 + 4h

Alloy 690 MA plate (Allvac): Specimen B25K

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Summary

Tried experimental approach based on Bill Mill’s experience(very similar to ANL’s practice)

Environmental enhancement depends on ∆K, and has a maximum at ∆K = 12 MPa m1/2

Despite the optimized conditions, the SCC CGRs for as-received Alloy 690 are extremely low or “zero”

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Alloy 690TT Specimens (as received condition)

Alloy 690TT CRDM tubing, 2541 – Heat WP142- specimen designation: C690 - 1/2T-CT specimens were cut from tubing (in as-received condition) in CR and LR orientations

LR

CR

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Excellent agreement between current ANL data (solid blue) and Bettis data (red) on time domain plots (left plot)

10-9

10-8

10-7

10-6

10-5

10-9 10-8 10-7 10-6 10-5

C690-CR-1

C690-LR-2

Alloy 690Simulated PWR Water at 320°C

Corrosion fatigue work by Bill Mills et al (Env Deg 2009)