ML18072A013

WCAP-18295-NP, Revision 0, Technical Justification for Eliminating Accumulator Line Rupture as the Structural Design Basis, Using Leak-Before-Break Methodology.

ML18072A013
Person / Time
Site:	Cook
Issue date:	01/31/2018
From:	Kirby C Westinghouse
To:	Office of Nuclear Reactor Regulation
References
AEP-NRC-2018-02 WCAP-18295-NP, Rev 0
Download: ML18072A013 (63)

Text

ENCLOSURE 7 TO AEP-NRC-2018-02 WCAP-18295-NP, Revision O "Technical Justification for Eliminating Accumulator Line Rupture as the Structural Design Basis for D.C. Cook Units 1 and 2, Using Leak-Before-Break Methodology" (Non-Proprietary)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 WCAP-18295-NP January 2018 Revision 0 Technical Justification for Eliminating Accumulator Line Rupture as the Structural Design Basis for D.C. Cook Units 1 and 2, Using Leak-Before-Break Methodology I

I I .

Westin .. ,*. , ghouse '

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 WCAP-18295-NP Revision.O Technical Justification for Eliminating Accumulator Line Rupture as the Structural Design Basis for D.C. Cook Units 1 and 2, Using Leak-Before-Break Methodology January 2018 Author: Christopher R. Kirby*

Structural Design and Analysis - I Reviewer: Eric D. Johnson*

Structural Design and Analysis - II Approved: Benjamin A. Leber, Manager*

Structural_ Design a11:d Analysis - II

• Electronically approved records are authenticated in the electronic document management system.

Westinghouse Electric Company LLC 1000 Westinghouse Drive Cranberry Township, PA 16066, USA

© 2018. Westingho:use Electric Company LLC All Rights Reserved

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 iii TABLE OF CONTENTS 1.0 Introduction ......................................................................................................................................... 1-1 1.1 Purpose ................................................................................................................................. 1-1 1.2 ScopeandObjectives ............................................................................................................ 1-1 1.3 References ............................................................................................................................. 1-2 2.0 Operation and Stability of the Reactor Coolant System .................................................................... 2-1 2.1 Stress Corrosion Cracking .................................................................................................... 2-1 2.2 Water Ham1ner ...................................................................................................................... 2-2 2.3 Low Cycle and High Cycle Fatigue ...................................................................................... 2-2 2.4 Other Possible Degradation During Service of the Accumulator Lines ............................... 2-3 2.5 References ................................................................. ,........................................................... 2-3 3.0 Pipe Geo1netry and Loading .......................... :................................................................................... 3-1 3.1

• Calculations of Loads and Stresses ..... :........................ :................ :....... :......................... :..... 3~1 3.2 Loads for Leak Rate Evaluation ................................................... ;....................................... 3-1 3.3 Load Combination for Crack Stability Analyses .................................................................. 3-2 3.4 References ............................................................................................................................. 3-3 4.0 Material Characterization................................................................................................................... 4-1 4.1 Accumulator Line Pipe Material and Weld Process ............................................................ .4-1 4.2 Tensile Properties .................................................................................................................. 4-1 4.3 Reference .............................................................................................................................. 4-1 5.0 Critical Locat.ions ........... ,................. , ....... ,........ , ....... ,........, ....... ,................. ,........,. ....... ,.........,. ....... ,...... 5-1 5.1 Critical Locations .................................................................................................................. 5-1 6.0 Leak Rate Predictions ........................................................................................................................ 6-1 6.1 Introduction ........................................................................................................................... 6-1 6.2 General Considerations ................................................... :..................................................... 6-1 6.3 Calculation Method ............................................................................................................... 6-1 6.4 Leak Rate Calculations ......................................................................................................... 6-2 6.5 References ............................................................................................................................. 6-3 7.0 Fracture Mechanics Evaluation .......................................................................................................... 7-1 7 .1 Global Failure Mechanism .................................................................................................... 7-1 7.2 Local Failure Mechanism ..................................................................................................... 7-2 7.3 Results of Crack Stability Evaluation ................................................................................... 7-2 7.4 References ............................................................................................................................. 7-2 8.0 Assessment of Fatigue Crack Growth ................................................................................................ 8-1

8. I References ............................................................................................................................. 8-1 9.0 Assessment of Margins ...................................................................................................................... 9-1 10.0 Conclusions ...................................................................................................................................... 10-1 Appendix A: Limit Moment. ......................................................................................................................... A-1 WCAP-18295-NP January 2018 Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 iv LIST OF TABLES Table 3-1 Summary ofD.C. Cook Unit 1 Piping Geometry and Normal Operating Condition for 10-inch Accumulator Lines ....................................................................... 3-4 Table 3-2 Summary ofD.C. Cook Unit 2 Piping Geometry and Normal Operating Condition for 10-inch Accumulator Lines ....................................................................... 3-5 Table 3-3 Summary ofD.C. Cook Unit 1 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop l ................................................................................. 3-6 Table 3-4 Summary ofD.C. Cook Unit 1 Normal Loads and Stresses for IO-inch Accumulator Injection Line Loop 2 ................................................................................. 3-7 Table 3-5 Summary ofD.C. Cook Unit 1 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 3 ..... ;....... .-........ ;................ ;....... .-........ ;....... .-........ ;....... 3-8 Table 3-6 Summary ofD.C. Cook Unit 1 Normal Loads and Stresses for IO-inch Accumulator Injection Line Loop 4 ................................................................................. 3-9 Table 3-7 Summary ofD.C. Cook Unit 2 Normal Loads and Stresses for IO-inch Accumulator Injection Line Loop l ............................................................................... 3-10 Table 3-8 Summary ofD.C. Cook Unit 2 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 2 ............................................................................... 3-11 Table 3-9 Summary ofD.C Cook Unit 2 N_ormal Loads and Stresses for 1~-inch . . .

Accumulator Injection Line Loop 3 ............................................................................... 3-12 Table 3-10 Summary ofD.C. Cook Unit 2 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 4 ............................................................................... 3-13 Table 3-11 Summary ofD.C. Cook Unit 1 Faulted Loads and Stresses for IO-inch Accumulator Injection Line Loop l ............................................................................... 3-14 Table 3-12 Summary ofD.C. Cook Unit 1 Faulted Loads and Stresses for IO-inch Accumulator Injection Line Loop 2 ............................................................................... 3-15 Table 3-13 Summary of D.C. Cook Unit 1 Faulted Loads and Stresses for IO-inch Accumulator Injection Line Loop 3 ............................................................................... 3-16 Table 3-14 Summary ofD.C. Cook Unit 1 Faulted Loads and Stresses for IO-inch Accumulator Injection Line Loop 4 ............................................................................... 3-17 Table 3-15 Summary ofD.C. Cook Unit 2 Faulted Loads and Stresses for IO-inch Accumulator Injection Line Loop 1 ............................................................................... 3-18 Table 3-16 Summary ofD.C. Cook Unit 2 Faulted Loads and Stresses for 10-inch Accumulator Injection Line Loop 2 ............................................................................... 3-19 Table 3-17 Summary ofD.C. Cook Unit 2 Faulted Loads and Stresses for IO-inch Accumulator Injection Line Loop 3 ............................................................................... 3-20 WCAP-18295-NP January 2018 Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 V Table 3-18 Summary ofD.C. Cook Unit 2 Faulted Loads and Stresses for IO-inch Accumulator Injection Line Loop 4 ............................................................................... 3-21 Table 4-1 Mechanical Properties for IO-inch Accumulator Lines Material at Operating Temperatures for D.C. Cook Units 1 and 2 ..................................................................... .4-1 Table 5-1 Summary ofD.C. Cook Unit 1 Piping Geometry and Normal Operating Condition for IO-inch Accumulator Lines and Critical Locations ................................... 5-1 Table 6-1 Flaw Sizes Yielding a Leak Rate of 8 gpm for the D.C. Cook Unit 1 and 2 10-inch Accumulator Lines ................................................................................................... 6-3 Table 7-1 Stability Results for the D.C. Cook Unit 1 and 2 IO-inch Accumulator Lines Based on Limit Load ........................................................................................................ 7-3 Table 9-1 Leakage Flaw Sizes, Cri_tical Flaw Sizes and Margins for D.C_. Cook Units 1 and 2 10-inch Accumulator Lines ........................................................................................... 9-1 WCAP-18295-NP January 2018 Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 vi LIST OF FIGURES Figure 3-1 10-inch Accumulator Line Layout Showing Segments for D.C. Cook Units 1 and 2 ............................................................................................................................... 3-22 Figure 3-2 D.C. Cook Unit 1 Accumulator Line Loop 1 Layout Showing Weld Locations with Node Points ............................................................................................................ 3-23 Figure 3-3 D.C. Cook Unit 1 Accumulator Line Loop 2 Layout Showing Weld Locations with Node Points ............................................................................................................ 3-24 Figure 3-4 D.C. Cook Unit 1 Accumulator Line Loop 3 Layout Showing Weld Locations with Node Points ............................................................................................................ 3-25 Figure 3-5 D.C. Cook Unit 1 Accumulator Line Loop 4 Layout Showing Weld Locations

• with Node Points .... ;....... ;....... .-........ ;....... .-........ ;....... .-........ ;....... .-........ ;....... .-........ ;....... ;.. 3-26 Figure 3-6 D.C. Cook Unit 2 Accumulator Line Loop 1 Layout Showing Weld Locations*

with Node Points ............................................................................................................ 3-27 Figure 3-7 D.C. Cook Unit 2 Accumulator Line Loop 2 Layout Showing Weld Locations with Node Points ............................................................................................................ 3-28 Figure 3-8 D.C. Cook Unit 2 Accumulator Line Loop 3 Layout Showing Weld Locations with Node Points ............................................................................................................ 3-29 Figure 3-_9 D.<;. Cook Unit 2 Accumulat~r Line Loop 4 Layout Showing_Weld Locations_ . .

with Node Points ............................................................................................................ 3-30 Figure 5-1 Layout Showing Critical Location Loop 4 Unit 2 ........................................................... 5-2 Figure 5-2 Layout Showing Critical Locations Loop 3 Unit 2 .......................................................... 5-3 Figure 5-3 Layout Showing Critical Locations Loop 1 Unit 2 .......................................................... 5-4 Figure 6-1 Analytical Predictions of Critical Flow Rates of Steam-Water Mixtures ....................... 6-4 Figure 6-2 ]a,c,e Pressure Ratio as a Function ofL/D .................................................... 6-5 Figure 6-3 Idealized Pressure Drop Profile Through a Postulated Crack ......................................... 6-6 Figure 7-1 ]a,c,e Stress Distribution .................................................................................... 7-4 FigureA-1 Pipe with a Through-Wall Crack in Bending ................................................................ A-2 WCAP-18295-NP January 2018 Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 1-1

1.0 INTRODUCTION

1.1 PURPOSE The current structural design basis for the D.C. Cook Units 1 and 2 10-inch accumulator lines (from the cold legs Loop 1, Loop 2, Loop 3 and Loop 4) require postulating non-mechanistic circumferential and longitudinal pipe breaks. This results in additional plant hardware (e.g., pipe whip restraints and jet shields) which would mitigate the dynamic consequences of the pipe breaks. It is, therefore, highly desirable to be realistic in the postulation of pipe breaks for the accumulator lines. Presented in this report are the descriptions of a mechanistic pipe break evaluation method and the analytical results that can be used for establishing that a circumferential type of break will not occur within the accumulator lines. The evaluations consider that circumferentially oriented flaws cover longitudinal cases.

1.2 SCOPE AND OBJECTIVES -

The purpose of this investigation is to demonstrate Leak Before Break (LBB) for the D.C. Cook Units 1 and 2 accumulator lines from the cold legs Loop 1, Loop 2, Loop 3 and Loop 4 to the isolation valves near the accumulator tanks. Schematic drawings of the piping system are shown in Section 3.0. The recommendations and criteria proposed in SRP 3.6.3 (References 1-1 and 1-2) are used in this evaluation.

The criteria and the resulting steps of the evaluation procedure can be briefly summarized as follows:

1. Calculate the applied loads based on as-built configuration. Identify the location(s) at which the highest.faulted stress oc;curs .

2. Identify the materials and the material properties.

3. Postulate a through-wall flaw at the governing location(s ). The size of the flaw should be large enough so that the leakage is assured of detection with margin using the installed leak detection equipment when the pipe is subjected to normal operating loads. Demonstrate that there is a margin of 10 between the calculated leak rate and the leak detection capability.

4. Using maximum faulted loads in the stability analysis, demonstrate that there is a margin of 2 between the leakage size flaw and the critical size flaw.

5. Review the operating history to ascertain that operating experience has indicated no particular susceptibility to failure from the effects of corrosion, water hammer, or low and high cycle fatigue.

6. For the material types used in the plant, provide representative material properties.

7. Demonstrate margin on applied load by combining the faulted loads by absolute summation method.

This report provides a fracture mechanics demonstration of accumulator line piping integrity for D.C.

Cook Units 1 and 2 consistent with the NRC's position for exemption from consideration of dynamic effects (Reference 1-3).

Introduction January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM_ ( This statement was added by the PRIME system upon its validation)

I

WESTINGHOUSE NON-PROPRIETARY CLASS 3 1-2 It should be noted that the terms "flaw" and "crack" have the same meaning and are used interchangeably.

"Governing location" and "critical location" are also used interchangeably throughout the report.

1.3 REFERENCES

1-1 Standard Review Plan: Public Comments Solicited; 3.6.3 Leak-Before-Break Evaluation Procedures; Federal Register/Vol. 52, No. 167/Friday August 28, 1987/Notices, pp. 32626-32633.

1-2 NUREG-0800 Revision 1, March 2007, Standard Review Plan: 3.6.3 Leak-Before-Break Evaluation Procedures.

1-3 Nuclear Regulatory Commission, 10 CFR 50, Modification of General Design Criteria 4 Requirements for Protection Against Dynamic Effects of Postulated Pipe Ruptures, Final Rule,

- Federal - Register/Vol. - 52, - No. 207 /Tuesday, -October 27, 1987/Rules -and - Regulations, pp. 41288-41295.

Introduction January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 2-1 2.0 OPERATION AND STABILITY OF THE REACTOR COOLANT SYSTEM 2.1 STRESS CORROSION CRACKING The Westinghouse reactor coolant system primary loops and connected Class 1 piping have an operating history that demonstrates the inherent operating stability characteristics of the design. This includes a low susceptibility to cracking failure from the effects of corrosion (e.g., intergranular stress corrosion cracking (IGSCC)). This operating history totals over 1400 reactor-years, including 16 plants each having over 30 years of operation, 10 other plants each with over 25 years of operation, 11 plants each with over 20 years

• of operation and 12 plants each with over 15 years of operation.

In 1978, the United States Nuclear Regulatory Commission (USNRC) formed the second Pipe Crack Study Group. (The first Pipe Crack Study Group (PCSG) established iri 1975 addressed cracking in boiling water reactors only.) One of the objectives of the second PCSG was to include a review of the potential for stress corrosion cracking in Pressurized Water Reactors (PWRs). The results of the study performed by the PCSG were presented in NUREG-0531 (Reference 2-1) entitled "Investigation and Evaluation of Stress Corrosion Cracking in Piping of Light Water Reactor Plants." In that report the PCSG stated:

"The PCSG has determined that the potential for stress-corrosion cracking in PWR primary system piping is extremely low because the ingredients that produce IGSCC are not all present.

. The. use of hydrazine additives and a hydrogen overpressure limit the oxygen in .the coolant to very low levels. Other impurities that might cause stress-corrosion cracking, such as halides or caustic, are also rigidly controlled. Only for brief periods during reactor shutdown when the coolant is exposed to the air and during the subsequent startup are conditions even marginally capable of producing stress-corrosion cracking in the primary systems of PWRs. Operating experience in PWRs supports this determination. To date, no stress corrosion cracking has been reported in the primary piping or safe ends of any PWR."

For stress corrosion cracking (SCC) to occur in piping, the following three conditions must exist simultaneously: high tensile stresses, susceptible material, and a corrosive environment. Since some residual stresses and some degree of material susceptibility exist in any stainless steel piping, the potential for stress corrosion is minimized by properly selecting a material immune to SCC as well as preventing the occurrence of a corrosive environment. The material specifications consider compatibility with the system's operating environment (both internal and external) as well as other material in the system, applicable ASME Code rules, fracture toughness, welding, fabrication, and processing.

The elements of a water environment known to increase the susceptibility of austenitic stainless steel to stress corrosion are: oxygen, fluorides, chlorides, hydroxides, hydrogen peroxide, and reduced forms of sulfur (e.g., sulfides, sulfites, and thionates ). Strict pipe cleaning standards prior to operation and careful control of water chemistry during plant operation are used to prevent the occurrence of a corrosive environment. Prior to being put into service, the piping is cleaned internally and externally. During flushes and preoperational testing, water chemistry is controlled in accordance with written specifications.

Operation and Stability of the Reactor Coolant System January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 2-2 Requirements on chlorides, fluorides, conductivity, and pH are included in the acceptance criteria for the piping.

During plant operation, the reactor coolant water chemistry is monitored and maintained within very specific limits. Contaminant concentrations are kept below the thresholds known to be conducive to stress corrosion cracking with the major water chemistry control standards being included in the plant operating procedures as a condition for plant operation. For example, during normal power operation, oxygen concentration in the RCS is expected to be in the parts per billion (ppb) range by controlling charging flow chemistry and maintaining hydrogen in the reactor coolant at specified concentrations.

Halogen concentrations are also stringently controlled by maintaining concentrations of chlorides and fluorides within the specified limits. Thus during plant operation, the likelihood of stress corrosion cracking is minimized.

During 1979, several instances of cracking in PWR feedwater piping led to the establishment of the third PCSG. The investigations of the PCSG reported in NUREG-0691 (Reference 2-2) further confirmed that no occurrences of IGSCC have been reported for PWR primary coolant systems.

Primary Water Stress Corrosion Cracking (PWSCC) occurred in V. C. Summer reactor vessel hot leg nozzle, Alloy 82/182 weld. It should be noted that this susceptible material is not found in the D.C. Cook Unit 1 and 2 accumulator lines.

2.2 WATER HAMMER Overall, there is a low potential for water hammer in the RCS and connecting accumulator lines since they are designed and operated to preclude the voiding condition in normally filled lines. The RCS and connecting accumulator lines including piping and components are designed for normal, upset, emergency, and faulted condition transients. The design requirements are conservative relative to both the number of transients and their severity. Relief valve actuation and the associated hydraulic transients following valve opening are considered in the system design. Other valve and pump actuations are relatively slow transients with no significant effect on the system dynamic loads. To ensure dynamic system stability, reactor coolant parameters are stringently controlled. Temperature during normal operation is maintained within a narrow range by the control rod positions; pressure is controlled also within a narrow range for steady-state conditions by the pressurizer heaters and pressurizer spray. The flow characteristics of the system remain constant during a fuel cycle because the only governing parameters, namely system resistance and the reactor coolant pump characteristics are controlled in the design process. Additionally, Westinghouse has instrumented typical reactor coolant systems to verify the flow and vibration characteristics of the system and the connecting auxiliary lines. Preoperational testing and operating experience has verified the Westinghouse approach. The operating transients of the RCS primary piping and connected accumulator lines are such that no significant water hammer can occur.

2.3 LOW CYCLE AND HIGH CYCLE FATIGUE The 1967 Edition of the B31.1 Code does not contain an explicit piping low cycle fatigue analysis requirement. The B31.1 piping complies with a stress range reduction factor to be applied to the allowable stress as a way to address fatigue from full temperature cycles for thermal expansion stress evaluation. The stress range reduction factor is 1.0 (i.e., no reduction) for equivalent full temperature Operation and Stability of the Reactor Coolant System January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 2-3 cycles less than 7000. For D.C. Cook Units 1 and 2, the equivalent full temperature cycles for the applicable design transients are less than 7000, so no reduction is required.

Pump vibrations during operation would result in high cycle fatigue loads in the piping system. During operation, an alarm signals the exceedance of the RC pump shaft vibration limits. Field vibration measurements have been made on the reactor coolant loop piping in a number of plants during hot functional testing. Stresses in the elbow below the RC pump have been found analytically to be very small, between 2 and 3 ksi at the highest. Field measurements on typical PWR plant indicate vibration stress amplitudes less than 1 ksi. When translated to the connecting accumulator lines, these stresses would be even lower, well below the fatigue endurance limit for the accumulator line materials and would result in an applied stress intensity factor below the threshold for fatigue crack growth.

2.4 OTHER POSSIBLE DEGRADATION DURING SERVICE OF THE ACCUMULATOR LINES The accumulator lines and the associated fittings for D.C. Cook Nuclear Power Plants are forged product forms, which are not susceptible to toughness degradation due to thermal aging.

The maximum normal operating temperature of the accumulator piping is about 549°F. This is well below the temperature that would cause any creep damage in stainless steel piping. Cleavage type failures are not a concern for the operating temperatures and the material used in the stainless steel piping of the accumulator lines.

Wall thinning by erosion and erosion-corrosion effects should not occur in the accumulator piping due to the low velocity, typically less than 1.0 ft/sec and the stainless steel material, which is highly resistant to these degradation mechanisms. Per NUREG-0691 (Reference 2-2), a study on pipe cracking in PWR piping reported only two incidents of wall thinning in stainless steel pipe and these were not in the accumulator line. The cause of wall thinning is related to the high water velocity and is therefore clearly not a mechanism that would affect the accumulator piping.

Brittle fracture for stainless steel material occurs when the operating temperature is about -200°F.

Accumulator line operating temperature is higher than 120°F and therefore, brittle fracture is not a concern for the accumulator line.

2.5 REFERENCES

2-1 Investigation and Evaluation of Stress-Corrosion Cracking in Piping of Light Water Reactor Plants, NUREG-0531, U.S. Nuclear Regulatory Commission, February 1979.

2-2 Investigation and Evaluation of Cracking Incidents in Piping in Pressurized Water Reactors, NUREG-0691, U.S. Nuclear Regulatory Commission, September 1980.

Operation and Stability of the Reactor Coolant System January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-1 3.0 PIPE GEOMETRY AND LOADING 3.1 CALCULATIONS OF LOADS AND STRESSES The stresses due to axial loads and bending moments are calculated by the following equation:

F M (3-1) cr=-:--+

A Z where, cr stress (psi)

F axial load (lbs)

M moment (in-lb)

A pipe cross-sectional area (in2) z section modulus (in 3)

The moments for the desired loading combinations are calculated by the following equation:

(3-2)

• where, X component of moment, Torsion Y component of bending moment M2 Z component of bending moment The axial load and moments for leak rate predictions and crack stability analyses are computed by the methods to be explained in Sections 3.2 and 3.3.

3.2 LOADS FOR LEAK RATE EVALUATION The normal operating loads for leak rate predictions are calculated by the following equations:

F Fnw + Frn + Fp (3-3)

Mx = (Mx)nw + (Mx)rn (3-4)

Mv (Mv)nw + (Mv)rn (3-5)

Mz (Mz)nw + (Mz)rn (3-6)

Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-2 The subscripts of the above equations represent the following loading cases:

DW dead weight TH = normal thermal expansion p = load due to internal pressure This method of combining loads is often referred to as the algebraic sum method (References 3-1 and 3-2). The LBB evaluations do not include moment effects due to pressure loading since the moment loading is significantly dominated by the thermal loads for normal operation and by the seismic loads for faulted events.

The dimensions and normal operating conditions are given in Tables 3-1 and 3-2. The loads based on this method of combination are provided in Tables 3-3 to 3-10 at all the weld locations; The weld naming convention used in this report is as follows:

Unit# - Isometric# - Spool Sheet# -Analysis Node#

3.3 LOAD COMBINATION FOR CRACK STABILITY ANALYSES In accordance with Standard Review Plan 3.6.3 (References 3-1 and 3-2), the absolute sum of loading components can be applied which results in higher magnitude of combined loads. If crack stability is demo~strat~d us.ing these r"oads," the LBB margin on *roads can be reduced from -V2 to 1.0. The absolute.

summation ofloads is shown in the following equations:

F = I FDW I + I FTH I + I F p I + I F SSEINERTIA I + I F SSEAM I (3-7)

Mx = I CMx)ow I + I (Mx)rn I + I (Mx)ssEINERTIAI + I (Mx)ssEAMI (3-8)

My= I (My)ow I+ I (My)rn I+ I (My)ssEINERTIAI + I (My)ssEAMI (3-9)

Mz = I (Mz)ow I + I (Mz)rn I + I (Mz)ssEINERTIAI + I (Mz)ssEAMI (3-10) where subscript SSEINERTIA refers to safe shutdown earthquake inertia, SSEAM is safe shutdown earthquake anchor motion. It is noted that the D.C. Cook piping analyses consider Design Basis Earthquake (DBE) as the seismic criteria, which is equivalent to Safe Shutdown Earthquake (SSE).

The loads so determined are used in the fracture mechanics evaluations (Section 7 .0) to demonstrate the LBB margins at the locations established to be the governing locations. These loads at all the weld locations are given in Tables 3-11 to 3-18.

Notes: For the accumulator lines, the LBB analysis will not be performed at the locations after the isolation valve near the accumulator tank since any break after the isolation valve will not have any effect on the primary loop piping system since there are two check valves, and the one isolation valve will Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-3 prevent the break propagation to the primary loop piping system. Figure 3-1 shows typical 10-inch accumulator line layout showing segments for D.C. Cook Units 1 and 2.

3.4 REFERENCES

3-1 Standard Review Plan: Public Comments Solicited; 3.6.3 Leak-Before-Break Evaluation Procedures; Federal Register/Vol. 52, No. 167/Friday, August 28, 1987/Notices, pp. 32626-32633.

3-2 NUREG-0800 Revision 1, March 2007, Standard Review Plan: 3.6.3 Leak-Before-Break Evaluation Procedures.

Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-4 Table 3-1 Summary ofD.C. Cook Unit 1 Piping Geometry and Normal Operating Condition for 10-inch Accumulator Lines Minimum Normal Operating Pipe Size & Wall Loop Segment Nodes Material Type Thickness Pressure Temperature Schedule (in)* (psig) (OF)

A376 TP316 or IO-inch I 416 to 412 0.896 2345 549 A403 WP316 Sch. 140 A376 TP316 or IO-inch 406-404 0.896 2235 549 A403 WP316 Sch. 140 1 II A376 TP316 or IO-inch 404 to 450 0.896 2235 120 A403 WP316 Sch. 140 A376 TP316 or IO-inch III 456 to 459 0.896 644 120 A403 WP316 Sch. 140 A376 TP316 or IO-inch I 361 to 358 0.896 2345 549 A403 WP316 Sch. 140 A376 TP316 or IO-inch 352 to 350 0.896 2235 549 A403 WP316 Sch. 140 2 II A376 TP316 or IO-inch 350 to 365 0.896 2235 120 A403 WP316 Sch. 140 A376 TP316 or IO-inch III 368 to 374 0.896 644 120 A403 WP316 Sch. 140 A376 TP316 or IO-inch I 171 to 168 0.896 2345 549 A403 WP316 Sch. 140 A376 TP316 or IO-inch 162 to 160 0.896 2235 549 A403 WP316 Sch. 140 3 II A376 TP316 or IO-inch 160 to 200 0.896 2235 120 A403 WP316 Sch. 140 A376 TP316 or IO-inch III 206 to 214 0.896 644 120 A403 WP316 Sch. 140 A376 TP316 or 10-inch I 307 to 304 0.896 2345 549 A403 WP316 Sch. 140 A376 TP316 or 10-inch 296 to 294 0.896 2235 549 A403 WP316 Sch. 140 4 II A376 TP316 or IO-inch 294 to 334 0.896 2235 120 A403 WP316 Sch. 140 A376 TP316 or IO-inch III 340 to 344 0.896 644 120 A403 WP316 Sch. 140 Notes: Pipe Outer Diameter= 10.75 in. Figure 3-1 shows the Segments. Node numbers are shown in Tables 3-3 to 3-6, Tables 3-11 to 3-14, and Figures 3-2 to 3-5.

The minimum wall thickness is conservatively based at the weld counterbore and not per ASME Code requirement.

Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-5 Table 3-2 Summary ofD.C. Cook Unit 2 Piping Geometry and Normal Operating Condition for 10-inch Accumulator Lines Minimum Normal Operating Pipe Size & Wall L_oop Segment Nodes Material Type Thickness Pressure Temperature Schedule (in) (psig) (OF)

A376 TP316 or 10-inch I 416 to 412 0.896 2345 549 A403 WP316 Sch. 140 A376 TP316 or 10-inch 406-404 0.896 2235 549 A403 WP316 Sch. 140 1 II A376 TP316 or 10-inch 404 to 450 0.896 2235 120 A403 WP316 Sch. 140 A376 TP316 or 10-inch III 456 to 460 0.896 644 120 A403 WP316 Sch. 140 A376 TP316 or 10-inch I 361 to 358 0.896 2345 549 A403 WP316 Sch. 140 A376 TP316 or 10-inch 352 to 350 0.896 2235 549 A403 WP316 Sch. 140 2 II A376 TP316 or 10-inch 350 to 365 0.896 2235 120 A403 WP316 Sch. 140 A376 TP316 or 10-incl).

III 368 to 374 0.896

• 644* 120 A403 WP316 Sch. 140 A376 TP316 or 10-inch I 171 to 168 0.896 2345 549 A403 WP316 Sch. 140 A376 TP316 or 10-inch 162 to 160 0.896 2235 549 A403 WP316 Sch. 140 3 II A376 TP316 or 10-inch 160 to 200 0.896 2235 120 A403 WP316 Sch. 140 A376 TP316 or 10-inch III 206 to 214 0.896 644 120 A403 WP316 Sch. 140 A376 TP316 or 10-inch I 307 to 304 0.896 2345 549 A403 WP316 Sch. 140 A376 TP316 or IO-inch 296 to 294 0.896 2235 549 A403 WP316 Sch. 140 4 II A376 TP316 or 10-inch 294 to 334 0.896 2235 120 A403 WP316 Sch. 140 A376 TP316 or 10-inch III 340 to 344 0.896 644 120 A403 WP316 Sch. 140 Notes: Pipe Outer Diameter= 10.75 in. Figure 3-1 shows the Segments. Node numbers are shown in Tables 3-7 to 3-10, Tables 3-15 to 3-18, and Figures 3-6 to 3-9.

The minimum wall thickness is conservatively based at the weld counterbore and not per ASME Code requirement.

Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-6 Table 3-3 Summary ofD.C. Cook Unit 1 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 1 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 1-SI-29-4-416 150,544 572,540 14,500 1-SI-29-4-412 151,904 480,244 13,087 1-S1-29-3R-406 144,981 372,401 11,129 1-S1-29-3R-404Y 144,974 359,707 10,927 1-SI-29-3R-404Z 144,603 329,751 101439 1-SI-29-3R-420N 145,021 138,676 7,428 1-SI-29-3R-420F 132,866 302,148 9,579 1-SI-29-2-426N 132,866 610,416 14,462 1-SI-29-2-426F 135,542 584,316 14,145 1-SI-29-2-428N 135,361 511,059 12,978 1-SI-29-2-428F 134,368 418,866 11,482

. 1-SI-29-2-430N 133,973 . 187,196 7,798.

1-SI-29-2-430F 134,456 217,782 8,300 1-S1-29-2-434N 133,786 596,012 14,267 1-S1-29-1-434F 132,348 606,825 14,386 l-S1-29-1-442N 140,744 19,109 5,379 1-SI-29-1-446F 144,828 24,490 5,612 1-SI-29-1-450 144,385 36,111 5,780 1-SI-28-1-456 42,094 48,043 2,279 1-SI-28-1-459 40,082 75,149 2,636 Notes:

• See Figure 3-2

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-7 Table 3-4 Summary ofD.C. Cook Unit 1 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 2 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 1-Sl-31-4-361 150,050 553,834 14,186 1-SI-31-4-358 150,454 464,800 12,790 1-S1-31-3R-352 143,522 360,126 10,882 1-S1-3 l-3R-350X 143,515 349,881 10,719 1-S1-31-3R-350Z 137,879 329,396 10,191 1-S1-31-3R-348F 137,317 146,068 7,267 1-S1-31-3R-348N 148,662 305,946 10,209 1-S1-31-3R-344F 148,661 583,194 14,601 1-S1-31-2-344N 145,839 543,364 13,868 1-S1-31-2-342F 146,048 429,755 12,076 1-S1-31-2-342N 146,006 341,910 10,683 1-S1-31-2-340F 146,140 228,057 8,884 1-S1-31-2-340N 146,570 173,557 8,036 1-SI-3 l-1A-338F 147,466 601,975 14,855 1-SI-31-1A-338N 148,841 616,807 15,139 l-S1-31-1A-332F 141,852 49,529 5,901 1-S1-31-IA-332N 140,753 34,468 5,623 1-S1-31-IA-330F 140,754 34,318 5,621 1-SI-3 l-lA-324 141,694 60,896 6,076 l-S1-31-1A-324Y 144,566 42,505 5,888 1-SI-31-IA-365 144,181 38,709 5,814 1-S1-30-1-369N 41,878 33,833 2,046 1-S1-30-1-372F 40,592 43,134 2,147 1-SI-30~ 1-374 40,592 56,445 2,358 Notes:

• See Figure 3-3

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-8 Table 3-5 Summary ofD.C. Cook Unit 1 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 3 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 1-SI-33-4-171 . 149,402 545,932 14,037 1-SI-33-4-168 149,924 457,435 12,654 1-S1-33-3R-162 142,990 350,539 10,711 1-S1-33-3R-160Y 142,990 339,778 10,540 1-S1-33-3R-160Z 144,283 320,142 10,276 1-S1-33-3R-174N 144,756 159,702 7,751 1-S1-33-3R-174F 132,912 329,603 10,015 1-SI-33-3R-178N 132,912 587,067 14,094 1-S1-33-2-178F 135,855 544,167 13,520 1-SI-33-2-l SON 135,647 426,577 11,650 1-SI-33-2-1 SOF 135,829 337,504 10,246 1-S1-33-2-182N 135,715 250,216 8,859 1-SI-33-2-182F 135,186 188,126 7,856 1-S1-33-2-184N 134,254 625,921 14,758 1-S1-33-1A-l84F 132,807 642,494 14,968 1-SI-33-1A-190N 140,752 82,640 6,386 1-SI-33-lA-196 140,684 98,910 6,641 1-S1-33-1A-196Y 143,247 91,767 6,621 1-SI-33-lA-200 142,911 82,455 6,461 1-Sl-32-1-206 40,580 111,590 3,231 1-SI-32-1-214 38,140 133,951 3,498 Notes:

• See Figure 3-4

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-9 Table 3-6 Summary ofD.C. Cook Unit 1 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 4 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 1-SI-35-4-307 149,603 558,147 14,238 1-SI-35-4-304 150,581 465,700 12,809 1-S1-35-3RR-296 143,647 361,774 10,912 1-S1-35-3RR-294Y 143,639 353,398 10,779 1-S1-35~3RR~294Z 144,601 331,148 10,461 1-S1-35-3RR-31 ON 145,069 143,595 7,507 1-S1-35-3RR-310F 132,993 316,630 9,813 1-S1-35-3RR-314N 132,994 595,022 14,223 1-S1-35-2R-314F 135,495 558,636 13,737 1-S1-35-2R-316N 135,287 442,239 11,885 1-S1-35-2R-316F 135,605 354,324 10,504 1-S1-35-2R-318N 135,493 268,494 9,140 l-S1-35-2R-318F 134,824 206,128 8,128 1-S1-35-2R-320N 133,895 596,295 14,275 l-S1-35-1-320F 132,895 605,939 14,392 1-S1-35-1-326N 140,594 37,566 5,666 1-S1-35-l-330F 144,765 29,682 5,692 l-SI-35-1-334 144,242 18,672 5,499 l-SI-34-1-340 42,031 27,037 1,944 1-SI-34-1-343 40,948 38,853 2,092 1-SI-34-1-344 40,949 50,665 2,280 Notes:

• See Figure 3-5

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-10 Table 3-7 Summary ofD.C. Cook Unit 2 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 1 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 2-SI-56-10-416 149,651 543,376 14,005 2-SI-56-10-412 150,029 460,335 12,704 2-SI-56-9-406 143,099 371,247 11,042 2-S1-56-9-404Y 143,099 364,094 10,929 2-S1-56-9-404Z 144,000 333,400 10,475 2-S1-56-9-420N 144,458 137,677 7,392 2-S1-56-8-420F 133,182 294,094 9,463 2-S1-56-8-426N 133,182 585,298 14,076 2-S1-56-8-426F 136,019 544,178 13,526 2-S1-56-7-428N 135,811 430,650 11,721 2-SI-56-7-428F 136,040 344,620 10,366 2-SI-56-7-430N 135,930 267,996 9,148 2-SI-56-7-430F 135,377 200,323 8,056 2-S1-56-6-434N 134,428 585,021 14,116 2-S1-56-6-434F 133,012 601,203 14,321 2-S1-56-5-442N 140,759 19,495 5,386 2-S1-56-4-446F 144,982 24,925 5,624 2-SI-56-4-450 144,461 36,168 5,784 2-SI-56-3-456 41,893 46,418 2,246 2-S1-56-3-458F 40,084 70,391 2,561 2-SI-56-3-460 40,083 84,642 2,787 Notes:

• See Figure 3-6

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-11 Table 3-8 Summary ofD.C. Cook Unit 2 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 2 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 2-SI-57-10-361 150,058 545,366 14,052 2-SI-57-10-358 150,601 455,303 12,645 2-SI-57-9-352 143,667 352,318 10,763 2-S1-57-9-350X 143,667 342,929 10,614 2-S1-57-9-350Z 137,932 330,093 10,204 2-S1-57-9-348F 137,369 146,848 7,281 2-S1-57-8-348N 148,713 307,489 10,235 2-S1-57-8-344F 148,713 583,312 14,604 2-S1-57-8-344N 145,886 543,484 13,871 2-S1-57-7-342F 146,134 429,243 12,071 2-S1-57-7-342N 146,088 340,780 10,668 2-S1-57-7-340F 146,250 226,938 8,870 2-S1-57-7-340N 146,749 172,793 8,030 2-S1-57-6-338F 147,823 608,808 14,976 2-S1-57-6-338N 148,892 618,226 15,164 2-S1-57-5-332F 141,297 88,253 6,495 2-S1-57-4-332N 141,478 86,492 6,473 2-SI-57-4-326F 141,478 99,948 6,686 2-S1-57-4-326N 142,887 111,859 6,926 2-S1-57-4-324Y 136,719 132,788 7,035 2-SI-57-4-365 136,328 103,172 6,552 2-SI-57-3-368 34,048 115,867 3,064 2-SI-57-3-374 40,010 86,160 2,808 Notes:

• See Figure 3-7

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-12 Table 3-9 Summary ofD.C. Cook Unit 2 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 3 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 2-SI-58-10-171 149,588 542,679 13,992 2-SI-58-10-168 150,011 454,313 12,608 2-SI-58-9-162 143,081 351,593 10,731 2-SI-58-9-I60Y 143,081 341,851 10,576 2-SI-58-9-l60Z 144,042 320;594 . 10,274 2-SI-58-9-174N 144,604 160,824 7,764 2-SI-58-8-l 74F 132,871 330,395 10,026 2-SI-58-8-178N 132,871 587,453 14,098 2-SI-58-8-l 78F 135,786 545,092 13,533 2-SI-58-7-180N 135,537 427,002 11,653 2-SI-58-7-180F 135,723 337,416 10,241 2-SI-58-7-182N 135,592 249,711 8,846 2-SI-58-7-I82F 134,989 187,744 7,843 2-SI-58-6-I84N 133,878 630,745 14,821 2-SI-58-6-l 84F 132,765 641,494 14,951 2-SI-58-5-190N 139,574 38,643 5,647 2-SI-58-4-I94F 144,633 39,516 5,843 2-SI-58-4-196Y 143,610 43,662 5,872 2-SI-58-4-200 143,270 58,945 6,102 2-SI-58-3-206 40,939 84,090 2,809 2-SI-58-3-212F 38,842 108,533 3,120 2-SI-58-3-214 38,842 106,898 3,094 Notes:

• See Figure 3-8

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation}

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-13 Table 3-10 Summary ofD.C. Cook Unit 2 Normal Loads and Stresses for 10-inch Accumulator Injection Line Loop 4 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 2-SI-59-10-307 150,095 554,493 14,198 2-SI-59-10-304 150,649 462,270 12,757 2-SI-59-9-296 143,709 357,048 10,840 2-SI-59-9-294Y 143,715 348,610 10,706 2-SI-59-9-294Z 144,752 . 338,702 10,587 2-SI-59-9-31 ON 145,176 138,638 7,433 2-SI-59-8-3 lOF 132,973 312,445 9,746 2-SI-59-8-314N 132,974 596,893 14,252 2-SI-59-8-314F 135,386 561,931 13,785 2-S1-59-7-316N 135,177 445,283 11,930 2-SI-59-7-316F 135,523 357,096 10,545 2-SI-59-7-31 SN 135,407 271,143 9,179 2-S1-59-7-318F 134,713 208,346 8,160 2-S1-59-6-320N 133,784 597,562 14,292 2-SI-59-6-320F 132,870 605,979 14,392 2-S1-59-5-326N 140,587 40,839 5,718 2-SI-59-4-330F 145,954 33,498 5,795 2-SI-59-4-334 145,430 25,819 5,655 2-SI-59-3-340 42,862 14,809 1,781 2-SI-59-3-344 40,932 35,700 2,042 Notes:

• See Figure 3-9

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-14 Table 3-11 Summary ofD.C. Cook Unit 1 Faulted Loads and Stresses for 10-inch Accumulator Injection Line Loop 1 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 1-SI-29-4-416 153,672 942,766 20,477 1-SI-29-4-412 153,946 781,220 17,928 1-S1-29-3R-406 146,721 541,792 13,875 1-S1-29-3R-404Y 146,708 511,106 13,388 1-S1-29-3R-404Z 148,186 469,759 . 12,786 1-S1-29-3R-420N 147,785 211,852 8,687 1-S1-29-3R-420F 150,017 359,241 11,102 1-S1-29-2-426N 149,655 665,307 15,937 1-S1-29-2-426F 147,300 650,728 15,621 1-S1-29-2-428N 147,466 585,585 14,595 1-S1-29-2-428F 148,333 485,703 13,044 1-S1-29-2-430N 148,854 253,259 9,381 1-S1-29-2-430F 148,404 265,934 9,566 l-SI-29-2-434N 149,155 664,249 15,902 l-S1-29-1-434F 150,250 654,108 15,781 1-S1-29-1-442N 143,611 203,227 8,399 1-S1-29-1-446F 149,385 157,310 7,880 1-SI-29-1-450 148,910 210,917 8,712 1-SI-28-1-456 46,553 312,358 6,627 1-SI-28-1-459 43,989 325,555 6,744 Notes:

• See Figure 3-2

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-15 Table 3-12 Summary ofD.C. Cook Unit 1 Faulted Loads and Stresses for 10-inch Accumulator Injection Line Loop 2 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 1-SI-31-4-361 154,404 952,033 20,650 1-SI-31-4-358 152,740 789,100 18,009 1-S1-31-3R-352 145,511 548,357 13,935 1-S1-3l-3R-350X 145,498 508,389 13,301 1-S1-31-3R-350Z 147,631 486,646 13,034 1-S1-31-3R-348F 147,051 240,974 9,121 1-S1-3 l-3R-348N 149,869 372,305 11,303 1-S1-31-3R-344F 149,387 638,071 15,496 1-S1-31-2-344N 147,035 610,125 14,968 1-S1-31-2-342F 147,236 495,600 13,162 1-S1-31-2-342N 146,912 408,000 11,762

• 1-S1-31-2-340F 147,103 288,840 9,882 l-S1-31-2-340N 147,764 231,000 8,989 1-S1-31-1A-338F 148,728 689,316 16,284 1-S1-31-1A-338N 149,712 673,084 16,062 1-S1-31-1A-332F 146,225 140,085 7,493 1-S1-31-1A-332N 147,023 154,999 7,758 l-S1-31-1A-330F 146,976 128,480 7,337 1-SI-3 l-IA-324 141,935 139,947 7,337 l-S1 IA-324Y 145,662 297,275 9,963 l-SI-31-IA-365 145,212 171,169 7,949 1-S1-30-l-369N 42,645 121,272 3,459 1-S1-30-1-372F 45,895 141,382 3,895 1-SI-30-1-374 45,911 133,357 3,768 Notes:

• See Figure 3-3

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-16 Table 3-13 Summary ofD.C. Cook Unit 1 Faulted Loads and Stresses for 10-inch Accumulator Injection Line Loop 3 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 1-SI-33-4-171 154,449 901,426 19,850 1-SI-33-4-168 151,850 761,463 17,539 l-S1-33-3R-162 144,623 536,440 13,714 l-S1-33-3R-l60Y 144,616 498,873 13,119 l-S1-33-3R-l60Z 147,423 442,778 12,332 1-S1-33-3R-174N 146,959 258,020 9,388 1-S1-33-3R-174F 149,946 400,054 11,746 l-S1-33-3R- l 78N 149,575 640,568 15,542 l-S1-33-2-178F 147,267 609,999 14,975 l-S1-33-2-180N 147,477 485,807 13,015

' l-S1-33-2-180F 146,974 397,219 11,594 l-S1-33-2-182N 147,107 301,798 10,087 l-S1-33-2-l 82F 147,947 237,093 9,092 1-S1-33-2-184N 148,927 694,425 16,372 1-S1-33-1A-l 84F 149,821 711,587 16,676 1-S1-33-1A-190N 144,313 276,976 9,593 l-SI-33-lA-196 143,545 304,639 10,003 1-S1-33-1A-196Y 149,256 399,444 11,711 l-SI lA-200 148,879 255,528 9,418 l-SI-32-1-206 46,374 222,432 5,196 l-SI-32-1-214 48,770 239,236 5,549 Notes:

• See Figure 3-4

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-17 Table 3-14 Summary ofD.C. Cook Unit 1 Faulted Loads and Stresses for 10-inch Accumulator Injection Line Loop 4 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 1-SI-35-4-307 154,554 933,994 20,370 1-SI-35-4-304 152,576 766,603 17,647 1-SI-35-3RR-296 145,345 521,590 13,505 1-SI-35-3RR-294Y 145,332 485,618 12,935 1-S1-35-3RR-294Z 147,986 474,798 12,859 1-S1-35-3RR-3 l0N 147,518 218,605 8,784 1-S1-35-3RR-3 l0F 149,705 368,180 11,232 1-S1-35-3RR-314N 149,405 635,330 15,453 1-SI-35-2R-314F 147,354 613,318 15,031 1-SI-35-2R-316N 147,555 500,811 13,256 1-SI-35-2R-316F 146,931 417,057 11,906 1-SI-35-2R-318N 147,080 330,240 10,536 1-SI-35-2R-3 l 8F 148,019 263,726 9,517 1-SI-35-2R-320N 149,016 669,413 15,979 1-SI-35-1-320F 149,633 653,715 15,753 1-SI-35-1-326N 142,784 201,489 8,342 1-SI-35-1-330F 147,894 156,026 7,806 1-SI-35-1-334 147,326 155,105 7,771 1-SI-34-1-340 45,110 231,951 5,301 1-SI-34-1-343 43,528 244,127 5,437 1-SI-34-1-344 43,360 222,408 5,087 Notes:

• See Figure 3-5

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-18 Table 3-15 Summary ofD.C. Cook Unit 2 Faulted Loads and Stresses for 10-inch Accumulator Injection Line Loop 1 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 2-SI-56-10-416 154,850 881,028 19,542 2-SI-56-10-412 152,074 738,135 17,178 2-SI-56-9-406 144,653 540,790 13,784 2-SI-56-9-404Y 144,644 510,587 13,305 2-SI-56-9-A04Z *147,675 474,565 12,844 2-SI-56-9-420N 147,200 221,137 8,813 2-SI-56-8-420F 149,883 360,838 11,122 2-SI-56-8-426N 149,401 635,776 15,460 2-SI-56-8-426F 146,934 605,903 14,898 2-SI-56-7-428N 147,130 496,465 13,171 2-SI-56-7-428F 146,624 409,344 11,773 2-S1-56-7-430N 146,754 330,436 10,528 2-SI-56-7-430F 147,567 261,721 9,469 2-SI-56-6-434N 148,583 654,713 15,731 2-SI-56-6-434F 149,711 649,740 15,693 2-SI-56-5-442N 143,803 225,713 8,763 2-SI-56-4-446F 149,901 169,423 8,091 2-SI-56-4-450 149,341 224,348 8,941 2-SI-56-3-456 46,670 334,073 6,975 2-SI-56-3-458F 44,438 339,098 6,974 2-SI-56-3-460 44,252 297,910 6,315 Notes:

• See Figure 3-6

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-19 Table 3-16 Summary ofD.C. Cook Unit 2 Faulted Loads and Stresses for 10-inch Accumulator Injection Line Loop 2 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 2-SI-57-10-361 154,785 930,327 20,320 2-SI-57-10-358 152,910 780,228 17,875 2-SI-57-9-352 145,580 550,743 13,975 2-SI-57-9-350X 145,569 511,768 13,358 2-SI-57-9-350Z 147,817 481,026 12,952 2-SI-57-9-348F 147,242 247,668 9,234 2-SI-57-8-348N 150,193 383,617 11,494 2-SI-57-8-344F 149,631 639,502 15,527 2-SI-57-8-344N 147,232 612,808 15,018 2-SI-57-7-342F 147,461 500,072 13,241 2-SI-57-7-342N 147,082 408,334 11,774 2-SI-57-7-340F 147,290 289,277 9,895 2-SI-57-7-340N 148,059 237,803 9,108 2-SI-57-6-338F 149,189 689,628 16,306 2-SI-57-6-338N 149,941 674,341 16,091 2-SI-57-5-332F 144,134 265,896 9,411 2-SI-57-4-332N 144,113 261,199 9,336 2-SI-57-4-326F 144,098 251,473 9,181 2-SI-57-4-326N 143,623 256,107 9,237 2-S1-57-4-324Y 147,576 407,080 11,772 2-SI-57-4-365 147,983 281,549 9,798 2-SI-57-3-368 49,754 210,309 5,126 2-SI-57-3-374 43,079 187,522 4,524 Notes:

• See Figure 3-7

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-20 Table 3-17 Summary ofD.C. Cook Unit 2 Faulted Loads and Stresses for 10-inch Accumulator Injection Line Loop 3 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 2-SI-58-10-171 155,131 963,864 20,864 2-SI-58-10-168 152,408 816,935 18,438 2-SI-58-9-162 145,111 586,733 14,529 2-SI-58-9-160Y 145,101 546,305 13,888 2-SI-58-9-160Z 147,868 482,583 12,978 2-S1-58-9-174N 147,313 276,331 9,691 2-S1-58-8-174F 150,295 414,861 11,993 2-S1-58-8-178N 149,785 648,744 15,679 2-S1-58-8-178F 147,541 . 620,256 15,147 2-S1-58-7-180N 147,779 497,191 13,206 2-S1-58-7-180F . 147,170 .409,449 . 11,794 2-S1-58-7-182N 147,331 312,371 10,262 2-S1-58-7-182F 148,328 248,448 9,286 2-S1-58-6-184N 149,512 720,276 16,803 2-S1-58-6-184F 150,085 729,325 16,967 2-S1-58-5-190N 144,043 183,813 8,107 2-S1-58-4-194F 156,146 220,688 9,128 2-S1-58-4-196Y 147,601 338,570 10,687 2-SI-58-4-200 147,198 202,172 8,512 2-SI-58-3-206 44,594 160,676 4,154 2-S1-58-3-212F 47,965 208,334 5,030 2-SI-58-3-214 47,974 196,809 4,848 Notes:

• See Figure 3-8

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-21 Table 3-18 Summary ofD.C. Cook Unit 2 Faulted Loads and Stresses for 10-inch Accumulator Injection Line Loop 4 Weld Location Axial Force Moment Total Stress Node (lbs) (in-lbs) (psi) 2-SI-59-10-307 155,202 970,257 20,968 2-SI-59-10-304 152,894 794,224 18,096 2-SI-59-9-296 145,478 534,370 13,712 2-S1-59-9-294Y 145,476 494,266 13,077 2-S1-59~9-294Z 147,968 483,080 12,990 2-SI-59-9-31 ON 147,567 228,424 8,941 2-SI-59-8-3 lOF 149,838 371,593 11,291 2-S1-59-8-314N 149,475 641,406 15,552 2-S1-59-8-314F 147,647 624,363 15,216 2-SI-59-7-316N 147,848 509,412 13,402 2-S1-59-7-316F 147,148 421,203 11,980 2-S1-59-7-318N 147,299

• 331,829 10,570 2-S1-59-7-318F 148,309 267,901 9,593 2-S1-59-6-320N 149,290 674,205 16,065 2-S1-59-6-320F 149,797 656,912 15,809 2-S1-59-5-326N 143,537 236,480 8,923 2-SI-59-4-330F 149,661 188,469 8,384 2-SI-59-4-334 149,098 190,010 8,388 2-SI-59-3-340 46,391 276,428 6,052 2-SI-59-3-344 44,025 292,096 6,215 Notes:

• See Figure 3-9

• Axial force includes pressure Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-22 I

J I

Accumulator Tank .,.

_ I_..§~gment 111......j

~1.-segmentll ~

Segment I Cold Leg Figure 3-110-inch Accumulator Line Layout Showing Segments for D.C. Cook Units 1 and 2 Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-23 Figure 3-2 D.C. Cook Unit 1 Accumulator Line Loop 1 Layout Showing Weld Locations with Node Points Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-24 Loop2 Cold Leg Figure 3-3 D.C. Cook Unit 1 Accumulator Line Loop 2 Layout Showing Weld Locations with Node Points Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-25 1'4 Figure 3-4 D.C. Cook Unit 1 Accumulator Line Loop 3 Layout Showing Weld Locations with Node Points Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-26

~ ...**

Loop4 Cold leg Figure 3-5 D.C. Cook Unit 1 Accumulator Line Loop 4 Layout Showing Weld Locations with Node Points Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-27 llC COLO L~G LOqP-1 Figure 3-6 D.C. Cook Unit 2 Accumulator Line Loop 1 Layout Showing Weld Locations with Node Points Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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I

WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-28 Figure 3-7 D.C. Cook Unit 2 Accumulator Line Loop 2 Layout Showing Weld Locations with Node

• Points Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-29 Figure 3-8 D.C. Cook Unit 2 Accumulator Line Loop 3 Layout Showing Weld Locations with Node Points Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 3-30

"(

Figure 3-9 D.C. Cook Unit 2 Accumulator Line Loop 4 Layout Showing Weld Locations with Node Points Pipe Geometry and Loading January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 4-1 4.0 MATERIAL CHARACTERIZATION 4.1 ACCUMULATOR LINE PIPE MATERIAL AND WELD PROCESS The material type of the accumulator line for D.C. Cook Units 1 and 2 is A376 TP316 (seamless pipe) and A403 WP316 (wrought fittings) for the pipe and fittings, respectively. The welding processes used are Submerged Arc Weld (SAW) and Shielded Metal Arc Weld (SMAW).

In the following sections the tensile properties of the materials are presented for use in the Leak-Before-Break analyses.

4.2 TENSILE PROPERTIES

• Certified Material Test Reports (CMTRs) with mechanical properties were not readily available for the D.C. Cook Units 1 and 2 accumulator lines. For the D.C. Cook Units 1 and 2 accumulator lines, the ASME Code mechanical properties were used to establish the tensile properties for the Leak-Before-Break analyses. The tensile properties for the pipe material are provided in Table 4-1 for the Units 1 and 2 accumulator lines.

For the A376 TP316 pipe material and the A403 WP316 fitting material, the representative properties at operating temperatures are established from the tensile properties interpolated from Section II of the ASME Boiler and Pressure Vessel Code (Reference 4-1). Code tensile properties at the operating

. temperatures were obtained by interpolaHng between vadous tensile Code properties.

The modulus of elasticity value was also interpolated from ASME Code properties, and Poisson's ratio was taken as 0.3.

4.3 REFERENCE 4-1 ASME Boiler and Pressure Vessel Code,Section II, Part D, "Properties (Customary) Materials,"

2007 Edition up to and including 2008 Addenda.

Table 4-1 Mechanical Properties for 10-inch Accumulator Lines Material at Operating Temperatures for D.C. Cook Units 1 and 2 Temperature Modulus of Yield Strength Ultimate Material (OF) Elasticity (E) (psi) Strength (psi)

(ksi)

A376 TP316 549 25,606 19,461 71,800 A403 WP316 A376 TP316 120 27,992 28,960 75,000 A403 WP316 Material Characterization January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 5-1 5.0 CRITICAL LOCATIONS 5.1 CRITICAL LOCATIONS The Leak-Before-Break (LBB) evaluation margins are to be demonstrated for the critical locations (governing locations). Such locations are established based on the loads (Section 3.3) and the material properties established in Section 4.2. These locations are defined below for the D.C. Cook accumulator lines.

Critical Locations for the 10-inch accumulator lines (see Table 5-1):

The welds in the accumulator line are fabricated using Shielded Metal Arc Weld (SMAW) and Submerged Arc Weld (SAW) for field and shop welds. The pipe material type is A376 TP 316 or A403 WP316 which have identical_ material properties. _The governing locations _were_ established on the basis of the_

pipe geometry, material type, operating temperature, operating pressure, and the highest faulted stresses at the welds.

Table 5-1 shows the highest faulted stresses and the corresponding weld location node for each welding process type in each segment of the IO-inch accumulator lines, enveloping both D.C. Cook Units 1 and 2.

Definition of the piping segments and the corresponding operating pressure and temperature parameters are from Tables 3-1 and 3-2. Figures 5-1 through 5-3 show the location of the critical welds.

ITable 5-1 Summary ofD.C. Cook Unit 1 Piping Geometry and Normal Operating Condition for 10-inch Accumulator Lines* and *critical Locations Welding Operating Operating Maximum Weld Location Segment Pipe Size Pressure Temperature Faulted Stress Process Node (psig) {°F) (psi)

I IO-inch SMAW 2,345 549 20,968 2-SI-59-I0-307 SAW 2,235 549 13,888 2-SI-58-9-160Y II IO-inch SMAW 2,235 549 14,529 2-SI-58-9-162 SAW 2,235 120 16,803 2-SI-58-6-184N SMAW 2,235 120 16,967 2-SI-58-6-l 84F III IO-inch SAW 644 120 6,974 2-SI-56-3-458F SMAW 644 120 6,975 2-SI-56-3-456 Critical Locations January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 5-2 RC COI.D UG \ *

• LlltiP 4

.... 1--------

Critical Location:

Segment I SMAW weld Figure 5-1 Layout Showing Critical Location Loop 4 Unit 2 Critical Locations January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 5-3 Critical Location:

Segment II SMAW weld Critical Location:

Segment II SAW weld Critical Location:

Segment II SMAW/SAW weld Figure 5-2 Layout Showing Critical Locations Loop 3 Unit 2 Critical Locations January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 5-4 Critical Location:

Segment Ill SMAW weld Critical Location:

Segment Ill SAW weld Figure 5-3 Layout Showing Critical Locations Loop 1 Unit 2 Critical Locations January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 6-1 6.0 LEAK RATE PREDICTIONS

6.1 INTRODUCTION

The purpose of this section is to discuss the method which is used to predict the flow through postulated through-wall cracks and present the leak rate calculation results for through-wall circumferential cracks.

6.2 GENERAL CONSIDERATIONS The flow of hot pressurized water through an opening to a lower back pressure causes flashing which can result in choking. For long channels where the ratio of the channel length, L, to hydraulic diameter, D8 ,

(L/DH) is greater than [

]a,c,e 6.3 CALCULATION METHOD The basic method used in the leak rate calculations is the method developed by [

]a,c,e The flow rate through a crack was calculated in the following manner. Figure 6-1 (from Reference 6-2) was used to estimate the critical pressure, Pc, for the accumulator line enthalpy condition and an assumed flow. Once Pc was found for a given mass flow, the [ ]a,c,e was found from Figure 6-2 (taken from Reference 6-2). For all cases considered, [

]",c,e therefore, this method will yield the two-phase pressure drop due to momentum effects as illustrated in Figure 6-3, where P0 is the operating pressure. Now using the assumed flow rate, G, the frictional pressure drop can be calculated using LlPr= [ (6-1) where the friction factor f is determined using the [ ]"'c,e The crack relative roughness, E, was obtained from fatigue crack data on stainless steel samples. The relative roughness value used in these calculations was [ r,c,e The frictional pressure drop using equation 6-1 is then calculated for the assumed flow rate and added to the [ ]a,c,e to obtain the total pressure drop from the primary system to the atmosphere.

Leak Rate Predictions January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRJETARY CLASS 3 6-2 That is, for the accumulator line:

Absolute Pressure - 14.7 = [ ]a,c,e (6-2) for a given assumed flow rate G. If the right-hand side of equation 6-2 does not agree with the pressure difference between the accumulator line and the atmosphere, then the procedure is repeated until equation 6-2 is satisfied to within an acceptable tolerance which in turn leads to a flow rate value for a given crack size.

For the single phase cases with lower temperature, leakage rate is calculated by the following equation (Reference 6-4) with the crack opening area obtained by the method from Reference 6-3.

Q = A (2gllP/kp)°" 5 ft 3/sec; (6-3)

Where, L'lP = pressure difference between stagnation and back pressure (lb/ft2), g = acceleration of gravity (ft/sec2), p = fluid density at atmospheric pressure (lb/ft3), k = friction loss including passage loss, inlet and outlet of the through-wall crack, A= crack opening area (ft2).

6.4 LEAK RATE CALCULATIONS Leak rate calculations were made as a function of crack length at the governing locations previously identified in Section 5.1. The normal operating loads_ of Table 3-3 through Table 3-6 (for Unit 1), and

. Table 3-7 throµgh Table 3-10 (for Unit 2) were applied,in th.ese calculations.. The crack opening areas were estimated using the method of Reference 6-3 and the leak rates were calculated using the formulation described above. The material properties of Section 4.2 (see Table 4-1) were used for these calculations.

The flaw sizes to yield a leak rate of 8 gpm were calculated at the governing locations and are given in Table 6-1 for D.C. Cook Unit 1 and Unit 2. The flaw sizes so determined are called leakage flaw sizes.

The D.C. Cook Unit 1 and 2 RCS pressure boundary leak detection system meets the intent of Regulatory Guide 1.45 and meets a leak detection capability of 0.8 gpm. Thus, to satisfy the margin of 10 on the leak rate, the flaw sizes (leakage flaw sizes) are determined which yield a leak rate of 8 gpm.

Leak Rate Predictions January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 6-3

6.5 REFERENCES

6-1 [

]a,c,e 6-2 M. M, El-Wakil, "Nuclear Heat Transport, International Textbook Company," New York, N.Y, 1971.

6-3 Tada, H., "The Effects of Shell Corrections on Stress Intensity Factors and the Crack Opening Area of Circumferential and a Longitudinal Through-Crack in a Pipe," Section 11-1, NUREG/CR-3464, September 1983.

6-4 Crane, D. P., "Handbook of Hydraulic Resistance Coefficient," Flow of Fluids through Valves,

• Fittings, and Pipe by the Engineering Division of Crane, 1981, Technical Paper No. 410.

Table 6-1 Flaw Sizes Yielding a Leak Rate of 8 gpm for the D.C. Cook Unit 1 and 2 10-inch Accumulator Lines Welding Weld Location Leakage Flaw Size Segment Pipe Size Process Node (in)

I 10-inch SMAW 2-SI-59-10-307 2.79 SAW 2-SI-58-9-160Y 3.68 SMAW 2-SI-58-9-162 3.64 II 10-inch SAW 2-SI-58-6-184N 3.03 SMAW 2-SI-58-6-184F 3.01 SAW 2-SI-56-3-458F 9.17 III 10-inch SMAW 2-SI-56-3-456 9.57 Leak Rate Predictions January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 6-4 a,c,e STAGNATION ENTHALPY C1o2 Btullb>

Figure 6-1 Analytical Predictions of Critical Flow Rates of Steam-Water Mixtures Leak Rate Predictions January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 6-5 a,c.e LENGTH/DIAMETER RATIO (UO>

Figure 6-2 [ i3,c,e Pressure Ratio as a Function of LID Leak Rate Predictions January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 6-6 a,c,e

[

Figure 6-3 Idealized Pressure Drop Profile Through a Postulated Crack Leak Rate Predictions January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 7-1 7.0 FRACTURE MECHANICS EVALUATION 7.1 GLOBAL FAILURE MECHANISM Determination of the conditions which lead to failure in stainless steel should be done with plastic fracture methodology because of the large amount of deformation accompanying fracture. One method for predicting the failure of ductile material is the plastic instability method, based on traditional plastic limit load concepts, but accounting for strain hardening and taking into account the presence of a flaw.

The flawed pipe is predicted to fail when the remaining net section reaches a stress level at which a plastic hinge is formed.

• The stress level at which this occurs is termed as the flow stress. The flow stress is generally taken as the average of the yield and ultimate tensile strength of the material at the temperature of interest. This methodology has been shown to be applicable to ductile piping through a large number of experiments and will be used here to predict the critical flaw size in accumulator line piping. The failure criterion has been obtained by requiring equilibrium of the section containing the

• flaw (Figure 7-1) when loads are applied. The detailed development is provided in Appendix A for a through-wall circumferential flaw in a pipe with internal pressure, axial force, and imposed bending moments. The limit moment for such a pipe is given by:

]a,c,e where:

[.

]a,c,e The analytical model described above accurately accounts for the piping internal pressure as well as imposed axial force as they affect the limit moment. Good agreement was found between the analytical predictions and the experimental results (Reference 7-1). For application of the limit load methodology, the material, including consideration of the configuration, must have a sufficient ductility and ductile tearing resistance to sustain the limit load.

Fracture Mechanics Evaluation January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 7-2 7.2 LOCAL FAILURE MECHANISM The local mechanism of failure is primarily dominated by the crack tip behavior in terms of crack-tip blunting, initiation, extension and finally cracks instability. The local stability will be assumed if the crack does not initiate at all. It has been accepted that the initiation toughness measured in terms of J1c from a J-integral resistance curve is a material parameter defining the crack initiation. If, for a given load, the calculated I-integral value is shown to be less than the J 10 of the material, then the crack will not initiate:

Stability analysis using this approach is perfonned for selected location.

7.3 RESULTS OF CRACK STABILITY EVALUATION A stability analysis based on limit load was performed. D.C. Cook Units 1 and 2 shop and field welds utilize SMAW and SAW weld processes. The "Z" factor for SMAW and SAW (References 7-2 and 7-3) are as follows:

. Z = 1.15 [1.0 + 0.013 (OD-4)] for SMAW Z = 1.30 [1.0 + 0.010 (OD-4)] for SAW where OD is the outer diameter of the pipe in inches.

The Z-factors for the SMAW and SAW were calculated for the critical locations, using the pipe outer diameter (OD) of 10.75 inches. The applied faulted loads (Table 3-11 through Table 3-14 for Unit 1 and Table* 3-15 through Table 3-18 for Unit 2) were increased by the Z factor. Material *properties. were* used from Table 4-1. Table 7-1 summarizes the results of the stability analyses based on limit load for Unit 1 and 2. The leakage flaw sizes are also presented in the same table.

Additionally, elastic-plastic fracture mechanics (EPFM) I-integral analysis for through-wall circumferential crack in a cylinder is performed for select locations using the procedure in the EPRI Fracture Mechanics Handbook (Reference 7-4). Table 7-1 shows the results of this analysis.

7.4 REFERENCES

7-1 Kanninen, M. F., et. al., "Mechanical Fracture Predictions for Sensitized Stainless Steel Piping with Circumferential Cracks," EPRI NP-192, September 1976.

7-2 Standard Review Plan; Public Comment Solicited; 3.6.3 Leak-Before-Break Evaluation Procedures; Federal Register/Vol. 52, No. 167/Friday,August 28, 1987/Notices, pp. 32626-32633.

7-3 NUREG-0800 Revision 1, March 2007, Standard Review Plan: 3.6.3 Leak-Before-Break Evaluation Procedures.

7-4 Kumar, V., German, M.D. and Shih, C. P., "An Engineering Approach for Elastic-Plastic Fracture Analysis," EPRI Report NP-1931, Project 1237-1, Electric Power Research Institute, July 1981.

Fracture Mechanics Evaluation January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 7-3 Table 7-1 Stability Results for the D.C. Cook Unit 1 and 2 10-inch Accumulator Lines Based on Limit Load Critical Leakage Flaw Welding Weld Location Segment Pipe Size Flaw Size Size Process Node (in) (in)

I 10-inch SMAW 2-SI-59-10-307 10.04 2.79

• sAW 2-SI-58-9-160Y 11.88 3.68 II 10-inch SMAW 2-SI-58-9-162 12.32 3.64 SAW 2-SI-58-6-184N 11.66 3.03 SMAW 2-SI-58-6-184F 12.30 3.01 1

III 10-inch SAW 2-SI-56-3-458F 18.34 9.17 1

SMAW 2-SI-56-3-456 19.14 . 9.57.

Note:

1. Calculated based on the methodology in Section 7.2 Fracture Mechanics Evaluation January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 7-4 Neutral Axis Figure 7-1 [ ]3,c,e Stress Distribution Fracture Mechanics Evaluation January 2018 WCAP-18295-NP Revision 0

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- ----- _ ___:____J

WESTINGHOUSE NON-PROPRIETARY CLASS 3 8-1 8.0 ASSESSMENT OF FATIGUE CRACK GROWTH The fatigue crack growth (FCG) analysis is not a requirement for the LBB analysis (see References 8-1 and 8-2) since the LBB analysis is based on the postulation of a through-wall flaw, whereas the FCG analysis is performed based on the surface flaw. In addition Reference 8-3 has indicated that, "the Commission deleted the fatigue crack growth analysis in the proposed rule. This requirement was found to be unnecessary because it was bounded by the crack stability analysis."

Also, since the growth of a flaw which leaks 8 gpm would be expected to be minimal between the time that leakage reaches 8 gpm and the time that the plant would be shutdown; therefore, only a limited number of cycles would be expected to occur.

8.1 REFERENCES

8-1 Standard Review Plan; Public Comment Solicited; 3.6.3 Leak-Before-Break Evaluation Procedures; Federal RegisterNol. 52, No. 167/Friday, August 28, 1987/Notices, pp. 32626-32633.

8-2 NUREG-0800 Revision 1, March 2007, Standard Review Plan: 3.6.3 Leak-Before-Break Evaluation Procedures.

8-3 Nuclear Regulatory Commission, 10 CFR 50, Modification of General Design Criteria 4 Requirements for Protection Against Dynamic Effects of Postulated Pipe Ruptures, Final Rule, Feder!:11 RegisterNol. 52, No. 2_07/Tuesday, October 27, 1987/Rules and .ReguJations, pp. 41288-41295.

Assessment of Fatigue Crack Growth January 2018 WCAP-18295-NP Revision 0

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WESTINGHOUSE NON-PROPRIETARY CLASS 3 9-1 9.0 ASSESSMENT OF MARGINS The results of the leak rates of Section 6.4 and the corresponding stability evaluations of Section 7.3 are used in performing the assessment of margins. Margins are shown in Table 9-1 for Unit 1 and 2. All the LBB recommended margins are satisfied.

In summary, margins at the critical locations relative to:

1. Flaw Size - Using faulted loads obtained by the absolute sum method, a margin of 2 or more exists between the critical flaw and the flaw having a leak rate of 8 gpm (the leakage flaw).

2. Leak Rate - A margin of 10 exists between the calculated leak rate from the leakage flaw and the plant leak detection capability of 0.8 gpm.

3. Loads - At the critical locations the leakage flaw was shown to be stable using the faulted loads obtained by the absolute sum method (i.e., a flaw twice the leakage flaw size is shown to be stable; hence the leakage flaw size is stable). A margin of 1 on loads using the absolute summation of faulted load combinations is satisfied.

Table 9-1 Leakage Flaw Sizes, Critical Flaw Sizes and Margins for D.C. Cook Units 1 and 2 10-inch Accumulator Lines Critical Leakage Welding Weld Location Segment Pipe Size Flaw Size Flaw Size Margin Process Node (in) (in)

ACC-1 IO-inch SMAW 2-SI-59-10-307 I0.04 2.79 3.6 SAW 2-SI-58-9-160Y 11.88 3.68 3.2 ACC-11 IO-inch SMAW 2-SI-58-9-162 12.32 3.64 3.4 SAW 2-SI-58-6-184N 11.66 3.03 3.8 SMAW 2-SI-58-6-184F 12.30 3.01 4.1 ACC-III IO-inch SAW 2-SI-56-3-458F 18.34 9.17 >2.0 1 SMAW 2-SI-56-3-456 19.14 9.57 >2.0 1 Notes:

1. Margin of 2.0 demonstrated based on the methodology in Section 7 .2 Assessment of Margins January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 10-1

10.0 CONCLUSION

S This report justifies the elimination of accumulator lines break from the structural design basis for D.C.

Cook Units 1 and 2 as follows:

a. Stress corrosion cracking is precluded by use of fracture resistant materials in the piping system and controls on reactor coolant chemistry, temperature, pressure, and flow during normal operation.

Note: Alloy 82/182 welds do not exist at the D.C. Cook Units 1 and 2 accumulator lines.

b. Water hammer should not occur in the accumulator line piping because of system design, testing, and operational considerations.

c. The effects oflow and high cycle fatigue on the integrity of the accumulator line piping are negligible.

d. Ample margin exists between the leak rate of small stable flaws and the capability of the D.C. Cook Units 1 and 2 reactor coolant system pressure boundary leakage detection systems.

e. Ample margin exists between the small stable flaw sizes of item (d) and larger stable flaws.

f. Ample margin exists in the material properties used to demonstrate end-of-service life (fully aged) stability of the critical flaws.

For the critical locations, flaws are identified that will be stable because of the ample margins described in d, e, and f above.

Based on loading, pipe geometry, welding process, and material properties considerations, enveloping critical (governing) locations were determined at which Leak-Before-Break crack stability evaluations were made. Through-wall flaw sizes were postulated which would cause a leak at a rate often (10) times the leakage detection system capability of the plant. Large margins for such flaw sizes were demonstrated against flaw instability. Finally, fatigue crack growth assessment was shown not to be an issue for the accumulator line piping. Therefore, the Leak-Before-Break conditions and margins are satisfied for D.C.

Cook Units 1 and 2 accumulator line piping. It is demonstrated that the dynamic effects of the pipe rupture resulting from postulated breaks in the accumulator line piping need not be considered in the structural design basis of D.C. Cook Units 1 and 2.

Conclusions January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 A-1 APPENDIX A: LIMIT MOMENT

] ~c,e Appendix A: Limit Moment January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WESTINGHOUSE NON-PROPRIETARY CLASS 3 A-2 4) o,r---~--------------------

(ii Figure A-1 Pipe with a Through-Wall Crack in Bending Appendix A: Limit Moment January 2018 WCAP-18295-NP Revision 0

• • • This record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)

WCAP-18295-NP Revision 0 Proprietary Class 3

• • This page was added to the quality record by the PRIME system upon its validation and shall not be considered in the page numbering of this document.**

Author Approval Kirby Christopher R Jan-16-2018 14:21 :34 Reviewer Approval Johnson Eric D Jan-17-201814:51:15 Manager Approval Leber Benjamin A Jan-18-2018 09:40:03 Files approved on Jan-18-2018

• • • Thls record was final approved on 1/18/2018 9:40:03 AM. ( This statement was added by the PRIME system upon its validation)