ML14099A169

Calculation No. 1200250.301, Revision 0, Flaw Tolerance Evaluation of Spent Fuel Cask MSB 4 for Palisades Power Plant

ML14099A169
Person / Time
Site:	Palisades, 07201007
Issue date:	04/04/2014
From:	Miessi G, Qian H Structural Integrity Associates
To:	Office of Nuclear Material Safety and Safeguards
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ML14099A192	List: ML14099A161 ML14099A169
References
ES/NRC 14-006 1200250.301, Rev. 0
Download: ML14099A169 (11)

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ES/NRC 14-006 April 4, 2014 Calculation No. 1200250.301, Revision 0, Flaw Tolerance Evaluation of Spent Fuel Cask MSB#4 for Palisades Power Plant (I paper copy)

V Structural Integrity Associates, Inc.

File No.: 1200250.301 Project No.: 1200250 CALCULATION PACKAGE Quality Program: E Nuclear 13 Commercial PROJECT NAME:

Flaw Tolerance Evaluation of Spent Fuel Cask MSB CONTRACT NO.:

626014 Rev. 0 CLIENT:

PLANT:

Energy Solutions Palisades Power Plant CALCULATION TITLE:

Flaw Tolerance Evaluation of Spent Fuel Cask MSB#4 for Palisades Power Plant Document Affected Project Manager Preparer(s) &

Revision Pages Revision Description Approval Checker(s)

Signature & Date Signatures & Date 0

1 - 10 Original Issue G. Angah Miessi GAM 07/23/12 Haiyang Qian HQ 07/23/12 G. Angah Miessi GAM 07/23/12 Page 1 of 10 F0306-OIRI

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Table of Contents

1.0 INTRODUCTION

/STATEMENT OF PROBLEM/ OBJECTIVE..........................

3 2.0 TECHNICAL APPROACH.....................................................................................

3 3.0 ASSUMPTIONS AND DESIGN INPUTS.............................................................

3 3.1 A ssum ptions................................................................................................

3 3.2 D esign Inputs.................................................................................................

4 4.0 FATIGUE CRACK GROWTH ANALYSIS...........................................................

5 5.0 CRACK STABILITY ANALYSIS...........................................................................

7 6.0 C O N C LU SIO N S.....................................................................................................

9 7.0 RE FEREN C ES........................................................................................................

10 List of Tables Table 1. Stress Range and Number of Cycles in the S&L Calculation..................................

4 Table 2. Stress Range and Number of Cycles for the New Fatigue Crack Growth C alculation..........................................................................................................

.... 5 Table 3. Change in Stress, Number of Cycles and Crack Growth Rate.................................

6 Table 4. Fatigue Crack Growth Results................................................................................

7 Table 5. Loads Applied for Flaw Stability Analysis.............................................................

7 Table 6. Flaw Stability A nalysis............................................................................................

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1.0 INTRODUCTION

/STATEMENT OF PROBLEM] OBJECTIVE In December 2007, Sargent & Lundy (S&L) performed a flaw analysis for a postulated axial surface flaw in the longitudinal weld of the Multi-Assembly Storage Basket (MSB-04) shell [1]. The analysis was performed for 50 years [I]. For license renewal purposes, Energy Solutions would like to extend the evaluation period from 50 years to 60 years. Therefore, a re-evaluation of the fatigue crack growth analysis is necessary to address the change in end-of-evaluation period.

2.0 TECHNICAL APPROACH In the existing S&L flaw analysis, the evaluation is based on linear elastic fracture mechanics (LEFM) since the MSB shell is fabricated from carbon steel material. The crack stability is evaluated by comparing the stress intensity factors based on the calculated final flaw size and MSB material toughness. In this calculation package, the same methodology will be applied. The crack growth will be re-calculated using the new stresses and number of cycles for the extended plant life provided by Energy Solutions [2].

3.0 ASSUMPTIONS AND DESIGN INPUTS 3.1 Assumptions The existing S&L flaw evaluation is based on the following assumptions [1]:

1. The largest flaw, among the three indications found in the longitudinal weld of MSB 004, is a subsurface flaw measuring %A" in length, along the MSB center line, and 3/16" in depth along the MSB radial direction. It is assumed in the existing S&L flaw evaluation, that the initial flaw is 1" in length and 0.5" in depth. Also, the flaw is conservatively assumed to be an internal surface flaw.

2. The effect of the longitudinal weld residual stress on the fatigue crack growth rate is considered by using the ASME Section XI [3] da/dN crack growth curve for R=I.

3. The stress intensity factors are calculated using formulae limited to Ri/t < 10, conservatively, for the much larger Ri/t ratio of the MSB shell.

In this calculation, the following assumptions are made, respectively:

1. The initial flaw size is assumed to be the same size. A maximum of 0.18" of corrosion is predicted on the MSB shell over a 60-year service period in a marine environment [2]. As such, using the same initial flaw size assumption leads to an a/t ratio of 0.61. Although the a/t ratio of File No.: 1200250.301 Page 3 of 10 Revision: 0 F0306-0IRI

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0.5 used in the existing evaluation is smaller than this new a/t ratio, it is still larger than the a/t ratio of 0.22 based on the actual flaw depth (3/16") and the corroded MSB shell thickness (0.82"). Therefore, in this evaluation, the original a/t ratio, 0.5, is still conservatively applied in calculating the stress intensity factors for the crack growth analysis. For the stability analysis, the actual a/t ratio is used.

2. The residual stress is still assumed to be the yield stress of the material [2]. Thus, the R ratio R=I is assumed in this calculation.

3. Since the actual Ri/t ratio is still much higher than 10. The formulae limited to Ri/t< 10 are still applied to calculate the stress intensity factors in this analysis, conservatively.

3.2 Design Inputs Table 1 summarizes the stress range and number of cycles used in the existing S&L fatigue crack growth analysis [1] and Table 2 presents the revised data for the extended service period of 60 years.

Table 1. Stress Range and Number of Cycles in the S&L Calculation Membrane, ksi Bending, ksi Load Cases Frequency Umin 0 max Umin Umax Pressure Test I / MSB life time 0

1.2 0

7.2 Vacuum Drying 1/ MSB life time

-0.976 1.2

-10.737 7.2 Daily Ambient Temp.

365 / year

-0.012 0.052

-0.135 0.314 Fluctuation Off-Normal Ambient 10 / year

-0.1 0.12

-0.154 1.72 Temp. Fluctuation Seismic/Handling 1 / year

-0.9 0.9

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Table 2. Stress Range and Number of Cycles for the New Fatigue Crack Growth Calculation Membrane, ksi Bending, ksi Load Cases Frequency (min Umax Umin Umax Pressure Test 2/ MSB life time 0

0.85 0

2.33 Vacuum Drying I/MSB life time

-1.71 0.85

-4.64 2.33 Daily Ambient Temp.

365 / year 0.69 0.81 2.28 2.66 Fluctuation Off-Normal Ambient 10 / year 0.78 1.43 3.71 5.80 Temp. Fluctuation Seismic/Handling 1/ year

-1.24 1.24

-4.05 4.05 4.0 FATIGUE CRACK GROWTH ANALYSIS The ratios between the stress ranges provided in Reference [2] and the corresponding ones used in the S&L calculation are calculated and listed in Table 3 for the all the load cases. The S&L calculation uses Zahoor's formulation for semi-elliptical axial flaw subjected to membrane and bending stress to calculate the stress intensity factors (Kl) [4]. The stress intensity factors are linearly proportional to the applied stress.

The crack growth rate da/dN is calculated using the following equations as documented in the S&L calculation:

da n

dN

where, C = 1.99-10-'°. [25.75- (2.88 - R)-3. 7]

n = 3.07 AKI*= KImar -- K,/min Kim ai As discussed in Section 3, the R ratio is conservatively considered to be R=1 due to residual stresses.

Thus, the crack growth rate da/dN is linearly proportional to AK 3 07. The ratio of crack growth rate File No.: 1200250.301 Revision: 0 Page 5 of 10 F0306-01RI

CStructural Integrity Associates, IncO between the rates based on the new stresses and the ones in the S&L calculation is calculated and listed in Table 3 for each load case. The total number of cycles for 50-year service life in the S&L analysis and for 60-year service life used in this calculation is also presented in Table 3 for each load case.

The crack growth rate of each load case evaluated in S&L calculation is presented in Table 4. The new crack growth values are calculated using the S&L crack growth rates, the da/dN ratios of each load case (conservatively taking the maximum of the membrane and bending stresses) and the total number of cycles as presented in Table 3.

For example, for the Daily Ambient Temperature Fluctuation condition, the crack growth in the depth direction is: Aa = 7.27E-08/18250 x 1.669 x 21900 = 1.45604E-07 inch.

The resulting final flaw sizes are:

Flaw depth = 0.5 + 0.000007178 = 0.500007178 in Flaw length = 2 * (0.5 + 0.0000012438) = 1.000002488 in Table 3. Change in Stress, Number of Cycles and Crack Growth Rate Total cycles Ratio on Membrane Ratio on Bending Load cases 50 60 Ao (AKI) da/dN ratio Acr (AK1) da/dN ratio years years Pressure Test 1

2 1.412 2.883 3.090 31.932 Vacuum Drying 1

1 0.850 0.607 2.573 18.209 Daily Ambient 18250 21,900 0.533 0.145 1.182 1.669 Temp. Fluctuation Off-Normal Ambient Temp.

50 60 0.338 0.036 0.897 0.715 Fluctuation Seismic/Handling 50 60 0.726 0.374 0.370 0.047 File No.: 1200250.301 Revision: 0 Page 6 of 10 F0306-0IRI

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Table 4. Fatigue Crack Growth Results S&L Flaw Growth Modified Flaw Growth Load Cases Depth Length Depth Length Pressure Test 2.34E-08 4.6E-09 1.49442E-06 2.93774E-07 Vacuum Drying 2.835E-07 4.13E-08 5.16225E-06 7.52032E-07 Daily Ambient Temp.

Fluctuation 7.27E-08 1.24E-08 1.45604E-07 2.48347E-08 Off-Normal Ambient Temp. Fluctuation 1.342E-07 1.89E-08 1.15144E-07 1.62162E-08 Seismic/Handling 5.807E-07 3.498E-07 2.60618E-07 1.5699E-07 Total 1.0945E-06 4.27E-07 7.17803E-06 1.24385E-06 5.0 CRACK STABILITY ANALYSIS Table 5 presents the normal and accident condition loads for flaw stability analysis in the existing S&L calculation [1] and the corresponding new loads provided in Reference 2.

Table 5. Loads Applied for Flaw Stability Analysis S&L Calculation Modified Stresses [21 Load Conditions Pm, ksi Pb, ksi Pm, ksi Pb, ksi Normal Conditioni 2.09 61.45 1.2 61.2 Off-Normal Condition1 3.49 65.11 Faulted/Accident 2 26 101 47.0 54.3 Notes: 1. Bending Stresses are calculated as (PL+Pb+Q-Pm) plus 54 ksi residual stress.

2. Bending Stresses are (PL+Pb-Pm) plus 54 ksi residual stress.

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The flaw stability analyses were performed in the existing S&L calculation using the rules of IWB-3610 and IWB-3620 and Appendix A of the EPRI Ductile Fracture Handbook [4], as summarized in the following equations:

K.(a,b,qtn, Gb) =Kla(a,b, bm) +Kjba(ab, ab)

where, For membrane stress The stress intensity factor at the deepest point is calculated as Kia (a,b, a=0,, (7rt)°.5Go (a,,(a, b))

with, Go(a) = 1.7767a - 2.5975a 2 + 2.752a 3 - 1.3237a 4 + 0.2363a' (0.102Ri - 0.02)0.05 t

alt a,,,

(a, (a / b)0.58 The stress intensity factor at the surface point is calculated as Gso(a, b) = [1.06 + 0.28(a) 2 Y(a)0'4 1 ao(am(a,b))

KI..b(a,b,q,,)=q,,," (2rt)°0-5."GSo (a, b)

For bending stress The stress intensity factor at the deepest point is calculated as KImb (a, b, ob)=ob (7rt).5 "G (ab(a,b))

GIO(a) = 0.1045ab(a,b) + 0.4189ab(a,b) 2 (0.102 Ri -

0.02)0.05 t

a (a, b) -

alt (a / b)°22 The stress intensity factor at the surface point is calculated as Gs,(a,b) = [0.25 + 0.2(,)2 ](°)0.26 G,(a,b) t b

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KIbb(a,b, 0b)=wb* (7rt)0 5 "Gs1 (aqb)

As shown in Section 4, the final flaw sizes corresponding to a 60-year service life are:

Flaw depth, a = 0.500007178 in Flaw length, b = 0.500001244 in The stress intensity factors and corresponding safety factors for each service level are calculated and presented in Table 6.

Table 6. Flaw Stability Analysis Service Level Ka, ksi*Iin KIc, ksi*in Safety Factor Normal Condition 23.587 89.2468' 3.78 Off-Normal Condition 26.176 89.24681 3.41 Accident/Faulted 62.763 153.01052 2.44 Note: 1. For normal and off-normal conditions, the material plane strain dynamic fracture toughness (Kid) is used [1].

2. For accident/faulted condition, the lower bound critical crack initiation stress intensity (Kc) is used [1].

6.0 CONCLUSION

S The fatigue crack growth evaluation performed using the new stresses for the MSB shell based on the current licensing basis calculations for the VSC-24 storage system has shown that, after 60 years of service, the postulated flaw in the MSB longitudinal weld grows 0.000007178 inch in the depth direction and 0.000002488 inch in the axial direction.

For the normal and off-normal conditions, the safety factors of the predicted final flaw after 60 years of service is larger than the ASME Section XI safety factor of 410=3.162. For the accident/faulted conditions, the corresponding safety factor is larger than the ASME Section XI safety factor of

'42=1.414.

Therefore, this updated evaluation has demonstrated that the predicted flaw growth in the MSB shell weld is negligible and the flaw remains stable under the specified loads for the 60-year service life.

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7.0 REFERENCES

I. Sargent & Lundy Calculation No. 2007-20168, Revision 00, "Palisades Weld Flaw Analysis for Loaded Spent Fuel Cask MSB No. 4."

2. Energy Solutions Calculation No. VSC-04.3205, Revision 0, "Palisades MSB #4 Crack Growth Analysis Inputs."

3. ASME Boiler &Pressure Vessel Code,Section XI, 1992 Edition.

4. Zahoor Akram, "Ductile Fracture Handbook," Vol. 3, Electric Power Research Institute, Research Project 1757-69, Section 8.1.3 and 8.1.4.

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