ML14301A254

Calculation No. 1200250.301, Revision 1, Flaw Tolerance Evaluation of Spent Fuel Cask MSB 4 for Palisades Power Plant

ML14301A254
Person / Time
Site:	Palisades, 07201007
Issue date:	10/24/2014
From:	EnergySolutions
To:	Office of Nuclear Material Safety and Safeguards
References
ES/NRC 14-018, TAC L24694 1200250.301, Rev. 1
Download: ML14301A254 (13)

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ES/NRC 14-018 October 24, 2014 Calculation No. 1200250.301, Revision 1, Flaw Tolerance Evaluation of Spent Fuel Cask MSB#4 for Palisades Power Plant (1 paper copy)

V Structural Integrity Associates, Inc!

File No.: 1200250.301 Project No.: 1200250 CALCULATION PACKAGE Quality Program: Z Nuclear E] 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 - 12 Original Issue G. Angah Miessi GAM 07/23/12 Haiyang Qian HQ 07/23/12 G. Angah Miessi GAM 07/23/12 1

All Updated Tables 3, 4, and 6, Sections 3.0, 6.0, and 7.0 to correct error in scaling parameters to address Structural G. A. Miessi G. A. Miessi Integrity Associates CAR GAM 09/08/2014 GAM 09/08/2014 14-011.

Added editorial changes.

G. S. Mukhim GSM 09/08/2014 Page 1 of 12 F0306-OIRI

CStructural Integrity Associates, IncO 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..........................................................................

8 5.1 Acceptance Criteria......................................................................................

8 5.2 Material Fracture Toughness........................................................................

8 5.3 L oads..........................................................................................................

.. 9 5.4 C alculations..................................................................................................

9

6.0 CONCLUSION

S....................................................................................................

12

7.0 REFERENCES

12 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.................................

7 Table 4. Fatigue Crack Growth Results..................................................................................

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

9 T able 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 an evaluation period of 50 years [I]. For license renewal purposes, Energy Solutions proposes 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 [I], 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 to the MSB material fracture toughness, with appropriate safety factors applied. In this calculation package, the same methodology as that contained in the S&L analysis [ 1 ] 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 3/4" 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 (Ri and t are the MSB shell inside radius and thickness, respectively).

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

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1. The initial flaw size is assumed to be the same size as that in the S&L analysis [1]. A maximum of 0.18" of corrosion is predicted on the 1" thick 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, based on a flaw depth of 0.5" and a corroded thickness of 0.82". Although the a/t ratio of 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 0.23 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 Load Cases Frequency Membrane, ksi Bending, ksi Onin Gmax AUml Omin Umax Agbl Pressure Test 1/ MSB life time 0

1.2 1.200 0

7.2 7.200 Vacuum Drying 1/ MSB life time

-0.976 1.2 2.176

-10.737 7.2 17.937 Daily Ambient Temp.

365 / year

-0.012 0.052 0.064

-0.135 0.314 0.449 Fluctuation Off-Normal Ambient 10 / year

-0.1 0.12 0.220

-0.154 1.72 1.874 Temp. Fluctuation Seismic/Handling 1 / year

-0.9 0.9 1.800

-1.5 1.5 3.000 File No.: 12 Revision: 1 00250.301 Page 4 of 12 F0306-OIRI

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Table 2. Stress Range and Number of Cycles for the New Fatigue Crack Growth Calculation Load Cases Frequency Membrane, ksi Bending, ksi Umin Umax A~m2 Ummin Umax ACb2 Pressure Test 2/ MSB life 0

0.85 0.85 0

2.33 2.33 time Vacuum Drying I/MSB life

-1.71 0.85 2.56

-4.64 2.33 6.97 time Daily Ambient Temp.

Fluctuation 365 / year 0.69 0.81 0.12 2.28 2.66 0.38 Off-Normal Ambient 10 / year 0.78 1.43 0.65 3.71 5.80 2.09 Temp. Fluctuation Seismic/Handling 1 / year

-1.24 1.24 2.48

-4.05 4.05 8.10 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 (KI) [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) 07]

n =3.07 AKI = Klmax - K.I min File No.: 1200250.301 Revision: 1 Page 5 of 12 F0306-01R I

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R = KImin 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 307. The ratio of crack growth rate between the rates based on the new stresses and the ones in the S&L calculation is calculated as:

da/dN ratio = Aa ratio3.0 7

where, Au ratio = Aa2/ Acml for membrane stress range and AGbE/Arbl for bending stress range The da/dN ratios are 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 ratio between the membrane and bending stress ratios) and the total number of cycles presented in Table 3 as follows:

da N2 dN N1

where, Aa is the crack growth N is the number of cycles da/dN is the ratio of crack growth rates, i.e., da/dN ratio Subscripts 1 and 2 refer to old and new values, respectively For example, for the Daily Ambient Temperature Fluctuation condition, the crack growth in the depth direction is: Aa2 = 7.27E-08 x 6.888 x 21900/18250 = 6.009E-07 inch.

The crack growth results from all the load cases are then summed to obtain the final depth and length of the postulated flaw after 60 years of crack growth. The resulting final flaw sizes are:

Flaw depth = 0.5 + 0.0000203 = 0.5000203 inch Flaw length = 1.0 + 0.0000193 = 1.0000193 inches File No.: 1200250.301 Page 6 of 12 Revision: 1 F0306-OIRI

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Table 3. Change in Stress, Number of Cycles and Crack Growth Rate Total cycles Ratios on Membrane Ratios on Bending Maximum Load cases 50 60 ratio da/dN AU da/dN da/dN years years ratio ratio ratio Ratio Pressure Test 1

2 0.708 0.347 0.324 0.031 0.347 Vacuum Drying 1

1 1.176 1.647 0.389 0.055 1.647 Daily Ambient 18250 21900 1.875 6.888 0.846 0.599 6.888 Temp. Fluctuation Off-Normal Ambient Temp.

500 600 2.955 27.823 1.115 1.398 27.823 Fluctuation Seismic/Handling 50 60 1.378 2.675 2.700 21.100 21.100 Note: Aa ratio = Aam2/Aami for membrane stress range and Aab2/Aabl for bending stress range Table 4. Fatigue Crack Growth Results S&L Flaw Growth Modified Flaw Growth Load Cases Depth Length Depth Length (in)

(in)

(in)

(in)

Pressure Test 2.34E-08 9.20E-09 1.62E-08 6.38E-09 Vacuum Drying 2.835E-07 8.26E-08 4.67E-07 1.36E-07 Daily Ambient Temp.

2.48E-08 2.05E-07 Fluctuation 7.27E-08 6.01E-07 Off-Normal Ambient Temp. Fluctuation 1.342E-07 4.48E-06 Seismic/Handling 5.807E-07 6.99E-07 1.47E-05 1.77E-05 Total Crack Growth 1.0945E-06 8.54E-07 2.03E-05 1.93E-05 File No.: 1200250.301 Revision: 1 Page 7 of 12 F0306-OIRI

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5.0 CRACK STABILITY ANALYSIS The flaw stability analyses in the existing S&L calculation were performed using the rules of IWB-3610 and IWB-3620 of Section XI of the ASME Boiler &Pressure Vessel Code [3]. The postulated flaw is stable, and thus acceptable, if the applied stress intensity factor for the fimal flaw size meets the prescribed acceptance criteria.

5.1 Acceptance Criteria Per IWB-3612, the flaw is acceptable if For normal (including upset and test) conditions K! < KId/l10

where, KI is the maximum applied stress intensity factor for the final flaw size Kid is the material fracture toughness based on crack arrest at the crack tip temperature For emergency and faulted conditions Ki < Ki/2

where, K1 is the maximum applied stress intensity factor for the final flaw size Kic is the material fracture toughness based on crack initiation at the crack tip temperature 5.2 Material Fracture Toughness The fracture toughness of the weld material is taken from the existing S&L calculation [ 1 ]. The values of both the fracture toughness based on crack arrest (Kid) and the fracture toughness based on crack initiation (Kic) were therein obtained from certified material test reports of the weld metal used for the seam weld of MSB#4 shell at 0°F (less than the minimum MSB shell service temperature of 5°F, conservatively) and material Charpy V-notch impact energy (CVN) correlations:

Kid = 89.247 ksi*in and Kl. = 153.011 ksi~in File No.: 1200250.301 Revision: 1 Page 8 of 12 F0306-OIRI

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5.3 Loads 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 [11 Modified Stresses [21 Load Conditions Pm, ksi Pb, ksi Pm, ksi Pb, ksi Normal Condition' 2.09 61.45 1.2 61.2 Off-Normal Condition' 3.49 65.11 Faulted/Accident2 26 101 47.0 54.3 Notes: 1. Bending Stresses are calculated as (PL+Pb+Q-Pm) plus 54 ksi residual stress [1].

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

5.4 Calculations The flaw stability analyses were performed in the existing S&L calculation using the rules of 1WB-3610 and IWB-3620 and Appendix A of the EPRI Ductile Fracture Handbook [4], as summarized in the following equations. The applied stress intensity factor is calculated as:

Ka(a, b,am,tb) =Kima(a, b, Gm) +Klba(a, b, rb)

where, For membrane stress The stress intensity factor at the deepest point is calculated as Klma,(a,b, rm)=am" (;'t).5" Go (a.m((a,b))

1.7767a - 2.5975a 2 + 2.752a 3 - 1.3237a 4 + 0.2363a 5

with, G 0 (a)=

(0.102 Ri - 0.02)0.05 t

a.(ab) =

alt (a lb)o58 File No.: 1200250.301 Revision: 1 Page 9 of 12 F0306-OIRI

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where, Gm = membrane stress (ksi) a = flaw depth (in) b = half flaw length (in) t = MSB shell thickness (in)

Ri= MSB shell inner radius (in)

The stress intensity factor at the surface point is calculated as Gs 0(a,b) = [1.06 + 0.28(t )2 ](ba)0.41 G0 (am (a,b))

t b

Kimb(a,b, a.m) =a.- (7rt)°'S'Gso (a,b)

For bending stress The stress intensity factor at the deepest point is calculated as KImb((a,b, Gb=ab) (7d) 5 Gi (ab(a,b))

G(a) = 0. 1045ab (a, b) + 0.4189ab (a, b)2 (0.102 Ri _ 0.02)0.05 t

b(a,b) -

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

KIbb(a,b, ab=ab* (rt)° 5 "Gsi (a,b)

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

Flaw depth, a = 0.50002 in Half-flaw length, b = 0.50001 in The stress intensity factors at the final flaw size for each service level are calculated and presented in Table 6 along with the corresponding safety factors, SF, calculated based on the acceptance criteria presented in Section 5.1 (SF = KId/Ka or Kic/Ka, as appropriate).

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Table 6. Flaw Stability Analysis Service Level KI, ksi*in Kid or Kl,, ksi'Jin Safety Factor Normal Condition 23.588 89.247' 3.78 Off-Normal Condition 26.177 89.247' 3.41 Accident/Faulted 62.764 153.0112 2.44 Notes: 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 (Kic) is used [1].

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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 2.03E-05 inch in the depth direction and 1.93E-05 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 are 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.

7.0 REFERENCES

1. Sargent & Lundy Calculation No. 2007-20168, Revision 00, "Palisades Weld Flaw Analysis for Loaded Spent Fuel Cask MSB No. 4," Structural Integrity Associates, Inc. File No. 1200250.201.

2. Energy Solutions Calculation No. VSC-04.3205, Revision 0, "Palisades MSB #4 Crack Growth Analysis Inputs," Structural Integrity Associates, Inc. File No. 1200250.201.

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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