ML15259A050

Areva Calculation 32-9244389-000, Revision 0, Byron/Braidwood RVCH Nozzle Idtb Repair Weld Anomaly.

ML15259A050
Person / Time
Site:	Byron, Braidwood
Issue date:	07/29/2015
From:	Noronha S J AREVA
To:	Exelon Generation Co, Office of Nuclear Reactor Regulation
Shared Package
ML15259A048	List: ML15259A049 ML15259A050 RS-15-236, Areva Calculation 32-9244389-000, Revision 0, Byron/Braidwood RVCH Nozzle Idtb Repair Weld Anomaly. RS-15-236, Areva Calculation 32-9244434-000, Revision 0, Byron and Braidwood RVCH Nozzle As-Left J-Groove Analysis. RS-15-236, Braidwood Station, Units 1 and 2 & Byron Station, Units 1 and 2 - Head Penetrations with Nozzles Having Pressure-Retaining Partial-Penetration J-Groove Welds
References
RS-15-236 32-9244389-000, Rev. 0
Download: ML15259A050 (53)

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{{#Wiki_filter:ATTACHMENT 3 Areva Calculation, "Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly 32-9244389-000", Revision 0 NON- PROPRIETARY Controlled Document 0402-01-F01 (Rev. 019, 6/25/2015) Title Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary PURPOSE AND

SUMMARY

OF RESULTS: Purpose: The purpose of this analysis is to perform fracture mechanics evaluation of a postulated anomaly in the Exelon Byron Units 1 and 2 and Braidwood Units I and 2 (Byron/Braidwood) Reactor Vessel Closure Head (RVCH)Control Rod Drive Mechanisms (CRDM) / Reactor Vessel Level Indication Systems (RVLIS) / Core Exit Thermocouple (CETC) Nozzles contingency modification. According to the design specification document, Reference [8.2], this anomaly is postulated to be a 0.1 inch flaw extending 360 degrees around the circumference at the "triple point" locations where there is a confluence of three materials; the RVCH low alloy steel base material, the SB-167 Alloy 600 existing nozzle or SB-I166 Alloy 690 replacement nozzle, and the [ ]weld material. Several potential flaw propagation paths are considered in the flaw evaluations. Flaw acceptance is based on the ASME B&PV Code, 2001 with 2002 & 2003 Addenda, Section Xl criteria for applied stress intensity factor (IWB-3612) and limit load (IWB-3642), Reference [8.1].Results: The results of the analyses demonstrate that the 0.10 inch weld anomaly is acceptable for a 40 year design life of the Byron/Braidwood CRDM/RVLIS/CETC Nozzle Repair. The minimum fracture toughness margins for flaw propagation Paths 3a/b/c and 4a/b/c have been shown to be acceptable as compared to the required margins of-/10 for normal/upset conditions and for emergency/faulted/test conditions per Section Xl, IWB-3612 of Reference [8.1].A limit load analysis was performed considering the ductile weld repair material along flaw propagation Paths la/b/c & 2aib/c. The analysis showed that for the postulated circumferential flaw the minimum margin on allowable stress is [ ] For the axial flaw the minimum margin on allowable flaw depth is [ ]Fracture toughness margins have also been demonstrated for the postulated cylindrical flaws. Also for the cylindrical flaws it is shown that the applied shear stress at the remaining ligament is less than the allowable shear stress per NB-3227.2, Reference [8.10].This document contains a total of 52 pages including pages 1-50 and Appendix A (2 pages).If the computer software used herein is not the latest version per the EASI list, THE DOCUMENT CONTAINS AP 0402-01 requires that justification be provided. ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE cODENERSION/REV CODENERSION/REV ii Yes AREVACGC 5.0 []NO Page 1 of 52 Controlled Document A AR EVA 0402-01-F01 (Rev. 019, 6125/2015) Document No. 32-9244389-000 Byron/Bradwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Review Method: Design Review (Detailed Check)E -]Alternate Calculation Signature Block Name and Title and PagesiSections (printed or typed) .signat~ure, L.P/LR Da~te Prepared/Reviewe~d/App~roved S~ilvester I. NoJ'onha Principal Engineer "7IZ' l(1 'Al___g ____r __V R Z'JWL2O!. All Tim Wiger, .Manager -,Kr.6.' A__ _.AII Notes: .P/R/A designates Preparer (I'), Reviewer (R), Approver (A);LP/LR designates Lead Preparer (LP.), Lead Reviewer (LR).In reviewing and appro0ving the irnitia.I release (Rev. 000), the .lead reviewer/approver shall designate CAll' in pages/sec~tions reviewed/app/roved. ....In reviewing ad iapproving revisions, the lead preparer and lead reviewer shiall use 'All' in the pages/sections reviewed/approved, 'All' means that the changes and the effect of the changes on the entire d~oument have been reviawed/approved. It does not mean that the lead reviewer/!app-rover has teviewed/approVed a.1l the pages of the document.Project Manager Approval of Customer References (N/A if not applicable)

• Name Title (printed or typed) (printed or typed) Signature Date_ _ _ _ _ _ ... ......_'_ .... ....... ..I .. ...... .. .. .. ....".. ...... ....._._f.*1 Page 2 Controlled Document A AR EVA 0402-01 -F01 (Rev. 019, 612512015)

Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Record of Revision Nei~o, Changed Brief Description / Change Authorization 000 jAll Initial Release___ .1 _______ I ____________ + +/- .4-+/- +/-Page 3 Controlled Document A ARE EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table of Contents Page SIGNATURE BLOCK .............................................................................................. 2 RECORD OF REVISION .......................................................................................... 3 LIST OF TABLES................................................................................................... 6 LIST OF FIGURES................................................................................................. 7 1.0 PURPOSE ANDSCOPE.................................................................................. 8 2.0 METHODOLOGY.......................................................................................... 9 2.1 Postulated Flaws........................................................................................... 9 2.2 Stress Intensity Factor (SIF) Solutions.................................................................. 10 2.3 Fatigue Crack Growth Laws ............................................................................. 12 2.4 Fatigue Crack Growth Calculations ..................................................................... 14 2.5 Acceptance Criteria ...................................................................................... 14 3.0 ASSUMPTIONS .......................................................................................... 16 3.1 Unverified Assumptions .................................................................................. 16 3.2 Justified Assumptions .................................................................................... 16 3.3 Modelling Simplifications................................................................................. 16 4.0 DESIGN INPUTS......................................................................................... 17 4.1 Geometry.................................. ................................................................ 17 4.2 Material Strength ......................................................................................... 17 4.3 Fracture Toughness...................................................................................... 18 4.4 Applied Stresses Intensity Factor Calculation.......................................................... 18 5.0 CALCULATIONS........................................................................................... 22 5.1 Circumferential Flaw for Paths la/b/c & 2a/b/c ........................................................ 22 5.2 Axial Flaw for Paths la/b/c & 2a/b/c.................................................................... 25 5.3 Cylindrical Flaw for Paths 3a/b/c & 4a/b/c .............................................................. 30 6.0 RESULTS ................................................................................................. 45 6.1 Fatigue Crack Growth of Continuous External Circumferential Flaw................................. 45 6.2 Fatigue Crack Growth of Semi-Circular External Axial Flaw .......................................... 45 6.3 Fatigue Crack Growth of Continuous Cylindrical Flaw along Paths 3a & 4a ........................ 45 6.4 Fatigue Crack Growth of Continuous Cylindrical Flaw along Paths 3b & 4b ........................ 46 6.5 Fatigue Crack Growth of Continuous Cylindrical Flaw along Paths 3c & 4c ........................ 47 7.0 COMPUTER USAGE .................................................................................... 48 7.1 Validation............................................................................ '...................... 48 Page 4 Controlied Document A AR N VA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table of Contents (continued) Page 7.2 Computer Files ........................................................................................... 48

8.0 REFERENCES

............................................................................................ 50 APPENDIX A:* VERIFICATION OF SIF FOR CYLINDRICAL FLAW ..................................... A-I Page 5 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary List of Tables Page Table 4-1 -Material Strength.................................................................................. 18 Table 4-2 -Operating Transients and Cycles ............................................................... 19 Table 4-3 -Replacement Nozzle Internal Mechanical Loads............................................... 20 Table 4-4 -Axial Stresses due to Seismic Loads............................................................ 21 Table 5-1 -Crack Growth for 3600 Circumferential Flaw (Paths la/b/c and 2a/b/c)...................... 22 Table 5-2 -Individual Transient Contribution to Crack Growth for 3600 Circumferential Flaw (Paths la/b and 2a/b) ............................................................................ 23 Table 5-3 -Individual Transient Contribution to Crack Growth for 3600 Circumferential Flaw (Paths Ic and 2c) ................................................................................. 24 Table 5-4 -End of Life Evaluation for Continuous External Circumferential Flaw (Limit Load).......... 25 Table 5-5 -Radial Crack Growth for Axial Flaw ............................................................. 25 Table 5-6 -Axial Crack Growth for Axial Flaw............................................................... 25 Table 5-7 -Individual Transient Contribution to Radial Crack Growth for Axial Flaw (Paths la/b and 2a/b) ............................ .............................................................. 26 Table 5-8 -Individual Transient Contribution to Axial Crack Growth for Axial Flaw (Paths la/b and 2a/b) .......................................................................................... 27 Table 5-9 -Individual Transient Contribution to Radial Crack Growth for Axial Flaw (Paths lc and 2c)............................................................................................. 28 Table 5-10 -Individual Transient Contribution to Axial Crack Growth for Axial Flaw (Paths lc and 2c)............................................................................................. 29 Table 5-11 -End of Life Evaluation for External Axial Flaw (Limit Load).................................. 30 Table 5-12 -First Year Crack Growth for Cylindrical Flaw along Path 3a (Bottom Corner).............. 31 Table 5-13 -First Year Crack Growth for Cylindrical Flaw along Path 3b (Bottom Corner).............. 32 Table 5-14 -First Year Crack Growth for Cylindrical Flaw along Path 3c (Bottom Corner).............. 33 Table 5-15 -First Year Crack Growth for Cylindrical Flaw along Path 4a (Bottom Corner).............. 34 Table 5-16 -First Year Crack Growth for Cylindrical Flaw along Path 4b (Bottom Corner).............. 35 Table 5-17 -First Year Crack Growth for Cylindrical Flaw along Path 4c (Bottom Corner).............. 36 Table 5-18 -First Year Crack Growth for Cylindrical Flaw along Path 3a (Top Corner) ................. 37 Table 5-19 -First Year Crack Growth for Cylindrical Flaw along Path 3b (Top Corner) ................. 38 Table 5-20 -First Year Crack Growth for Cylindrical Flaw along Path 3c (Top Corner) ................. 39 Table 5-21 -First Year Crack Growth for Cylindrical Flaw along Path 4a (Top Corner) ................. 40 Table 5-22 -First Year Crack Growth for Cylindrical Flaw along Path 4b (Top Corner) ................. 41 Table 5-23 -First Year Crack Growth for Cylindrical Flaw along Path 4c (Top Corner) ................. 42 Table 5-24 -Final Crack Depth for Cylindrical Flaw (Bottom Corner) ..................................... 42 Table 5-25 -Final Crack Depth for Cylindrical Flaw (Top Corner) ......................................... 42 Table 5-26 -LEFM Margin for Cylindrical Flaw.............................................................. 44 Table 7-1 -Computer Files for Crack Growth Evaluation .................................................. 49 Page 6 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary List of Figures Page Figure 2-1 -Illustration of Crack Propagation Paths.......................................................... 10 Figure 2-2 -OD, Partial Through-Wall, 3600 Circumferential Flaw.......................................... 11 Figure 2-3 -OD, Partial Through-Wall, Semi-Elliptical Axial Flaw .......................................... 11 Page 7 Controlled Document A ARE EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

1.0 PURPOSE

AND SCOPE As required by the Design Specification document, Reference [8.2], the purpose of this analysis is to perform fracture mechanics evaluation of a postulated anomaly in the Exelon Byron Units 1 and 2 and Braidwood Units 1& 2 (Byron/Braidwood) Reactor Vessel Closure Head (RVCH) Control Rod Drive Mechanisms (CRDM) /Reactor Vessel Level Indication Systems (RVLIS) / Core Exit Thermocouple (CETC) Nozzle contingency modification. Per Reference [8.2], this anomaly is postulated to be a 0.1 inch flaw extending 360 degrees around the circumference at the "triple point" locations where there is a confluence of three materials; the RVCH low alloy steel base material, the SB-167 Alloy 600 existing nozzle or SB-166 Alloy 690 replacement nozzle, and the[ ] weld material. Several potential flaw propagation paths are considered in the flaw evaluations. Flaw acceptance is based on the ASME B&PV Code, 2001 with 2002 & 2003 Addenda, Section XI criteria for applied stress intensity factor (IWB-36 12) and limit load (IWB-3 642), Reference [8.1].The repair scope includes potential nozzle modifications at any of the Control Rod Drive Mechanisms (CRDM), the Reactor Vessel Level Indication Systems (RVLIS) and/or the Core Exit Thermocouple (CETC). Therefore, the Section XI analysis must bound all CRDM, RVLJS, and CETC locations on the RVCH. Per Reference [8.3], the CETC Nozzle is considered to be the controlling component, and therefore, this analysis will consider the CETC Nozzle only.The present fracture mechanics analysis provides justification, in accordance with Section XI of the ASME B&PV Code, Reference [8.1], for operating with the postulated weld anomaly at the upper and lower triple point locations defined for the CETC nozzle. Predictions of fatigue crack growth are based on the original design life of 40 years, Reference [8.4].Page 8 Controlled Document A A R EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

2.0 METHODOLOGY

This section presents several aspects of linear elastic fr'acture mechanics (LEFM) and limit load analysis (used to address the ductile weld materials) that form the basis of the present flaw evaluation.

2.1 Postulated

Flaws The triple point weld anomaly is postulated to be semi-circular in shape with an initial depth of 0.1", as indicated in Reference [8.2]. It is further assumed that the anomaly extends 3600 around the new repair weld.The anomaly could be located in the upper and lower triple point regions, the regions are called "triple point" since three materials intersect at these locations. The materials are:* The existing nozzle material, SB- 167 -Alloy 600 (Upper Triple Point) or the replacement nozzle material, SB-166 -Alloy 690 (Lower Triple Point), Reference [8.2].* The new weld filler material, [ ] Reference [8.2].* The RV closure head material, SA-533 Grade B Class 1, Reference [8.2].Three flaw types are postulated to simulate various orientations and propagation directions for the weld anomaly.A circumferential flaw and an axial flaw at the outside surface of the new weld would both propagate in the horizontal direction toward the inside surface of the new weld. The cylindrically oriented flaws along the interface between the weld and RV closure head would propagate downward between the two components from the top flaw tip and upward between the two components from the bottom flaw tip. The horizontal and vertical flaw propagation directions are represented in Figure 2-1, Reference [8.3], by separate paths for the downhill and uphill sides of the Nozzle, as discussed below. For both these directions, fatigue crack growth will be calculated. Horizontal Direction (Paths la/b/c and 2a/b/c): Flaw propagation is across the Nozzle IDTB Weld wall thickness from the OD to the U) of the JDTB Weld. These are the shortest paths through the component wall passing through the new [ ] weld material at the upper (Paths la, lb and ic) and lower triple points (Paths 2a, 2b, and 2c), Reference [8.2].For completeness, two types of flaws are postulated at the outside surface of the tube. A 3600 continuous circumferential flaw, lying in a horizontal plane, is considered to be a conservative representation of crack-like defects that may exist in the weld anomaly. This flaw would be subjected to axial stresses in the tube. An axially oriented semi-circular outside surface flaw is also considered since it would lie in a plane that is normal to the higher circumferential stresses. Both of these flaws would propagate toward the inside surface of the tube.Vertical Direction (Paths 3 a/b/c and 4a/b/c): Flaw propagation is at the outside surface of the repair weld between the weld and the RVCH. A continuous surface flaw is postulated to lie along this cylindrical interface between the two materials. This flaw, driven by radial stresses, may propagate along either the new [ ] weld material or the SA-533, Gr. B RVCH material from either corner (top or bottom). Flaws along Paths 3a, 3b, and 3c are postulated in the weld and flaws along Paths 4a, 4b, and 4c are postulated in the RVCH.Page 9 A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Figure 2-1 -Illustration of Crack Propagation Paths 2.2 Stress Intensity Factor (SIF) Solutions Three flaw types are postulated for the current evaluation of the weld anomaly defect at the triple points. For paths l a/b/c and 2afb/c both 3600 circumferential and axial surface flaws at the OD of the IDTB weld are postulated. The solutions for both types of flaws are available in the AREVACGC code, Reference [8.5], which implements the Stress Intensity Factor (SIF) evaluation for these types of flaws using the weight function method.AREVACGC performs the fatigue crack growth calculations. The schematics for both the 3600 circumferential and axial flaws postulated at the OD of the IDTB weld are illustrated in Figure 2-2 and Figure 2-3, respectively. For the vertical paths (3afb/c and 4afb/c), a cylindrical flaw is postulated along the interface between the new repair weld and the RV head material. The potential for flaw propagation along this interface is likely if radial stresses are significant between the weld and head. This assessment utilizes an SIF solution for a continuous surface crack in a flat plate from Appendix A Section XI of the ASME B&PV Code, Reference [8.11. Flat plate solutions are routinely used to evaluate flaws in cylindrical components such as the repair weld. The flat plate solution is inherently conservative for this application since the added constraint provided by the cylindrical structure reduces the crack opening displacements. Crack growth analysis is performed considering propagation through the [ I weld metal or the low alloy steel RVCH material. To facilitate the calculation of the SIF for the cylindrical flaw, a visual basic code, KIeff edge, was developed based on the theory in Appendix A Section XI of the ASME B&PV Code, Reference [8.1 ]. Appendix A of this document provides verification of the Kleff_edge visual basic function against hand calculations. Page 10 A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Postulated 3600 Circumferential Flaw at the OD Figure 2-2 -OD, Partial Through-Wall, 3600 Circumferential Flaw!, Flaw Propagation Path-t Where, a =initial flaw depth S= 2a =flaw length t = thickness Figure 2-3 -OD, Partial Through-Wall, Semi-Elliptical Axial Flaw Page 11 Controlled Document A ARE EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

2.3 Fatigue

Crack Growth Laws Flaw growth due to fatigue is characterized by da Where C 0 and n are constants that depend on the material and environmental conditions, AK 1 is the range of applied stress intensity factor in terms of ksi~in, and da/dN is the incremental flaw growth in terms of inches/cycle. For the embedded weld anomaly considered in the present analysis at the upper triple point, it is appropriate to use crack growth rates for an air environment. For the embedded weld anomaly considered at the lower triple point, the crack growth rates for material exposed to light-water reactor environments is utilized.Fatigue crack growth is also dependent on the ratio of the minimum to the maximum stress intensity factor; i.e., R =Kmtn/Kmax SA-533 Grade B Low Alloy Steel Material (RVCH)From Article A-4300 of the 2001 Edition with 2002 thr'ough 2003 Addenda of Section XI, Reference [8.1], the fatigue crack growth constants for flaws in an air environment are: n =3.07 Co = 1.99 xl0 1° S S is a scaling parameter to account for the R ratio and is given by S = 25.72 (2.88 -R)-3°7 , where 0 < R _< 1 and AK 1 = Kmax -Kmm. For R < 0, AK 1 depends on the crack depth, a, and the flow stress, (3 f. The flow stress is defined by arf = where is the yield strength and is the ultimate tensile strength. For -2 < R 0 and Kmax -Kmin < 1.12 (yf'jlta, S~l and AK 1 = Kmax- For R< -2 and Kmax -Kmin < 1.12 O3f'Vl/ta, S = 1 and ALK 1= (1-R) Kmax3. ForkR < 0 and Kmax -Kmim > 1.12 afr/bra, S = 1 and AKI = Kmax -Kmin.From Article A-43 00, Reference [8.1], for material exposed to light-water reactor environments, the fatigue crack growth constants are: AK 1 = Kmax -Km.0O<RS<O.25, AK < 17.74 n = 5.95 S= 1.0 Co = 1.02 x 1-2 AK 1?> 17.74 n =1.95 S=1.0 Co 0= 1.01 x 10-7S 0.25 < R < 0.65, AkK 1 < 17.74 [(3.75R + 0.06)'(26.9R -5.725)]0.25 n =5.95 S = 26.9S -5.725 Co = 1.02 x 10-]2 S AK 1> 17.74[(3.75R + 0.06)/(26.9R -5.725)]0.2 Page 12 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary n = 1.95 S =3.75R + 0.06 Co = 1.01 x107 0.65 <R_<l100, AK < 12.04 n =5.95 S =11.76 C = 1.02 x 10-1 2 S AK 1 > 12.04 n = 1.95 S =2.5 Co = 1.01 x 10-7 S Additionally, per A-4300(b)(2) of Reference [8.1], if the fatigue crack growth rate from light-water reactor environments is lower than air environments, the rate in air should be used.[ ] Weld Metal Flaw growth in the IDTB Weld ([ ]) and/or Alloy Nozzle in contact with air due to cyclic loading is calculated using the fatigue crack growth model presented in NUREG/CR-6907, Reference [8.6]. As per reference[8.6] a multiplier of 2 is applied to the Alloy 600 crack growth rate. Crack growth analysis is then conducted on a cycle-by-cycle basis to the end of service life. The crack growth rate equation for [ ] in air to be used is then given by: da-= 2 cSR(AXK)" Where AK is the stress intensity factor range in terms of MPa'.Im and da/dN is the crack growth rate in terms of mn/cycle, and C = 4.835x10-' 4 + 1.622x10'6 T -1.490x10'8 T 2 + 4.355x10-2 1 T 3 SR= [1i -0.82R]" 2 2 T = degrees C n=4.1 R = Km/ Km~The fatigue growth rate of [ ] in contact with light-water reactor environment due to cyclic loading is calculated using the fatigue crack growth model presented in NUJREG/CR-6907, Reference [8.6]. As per reference [8.6] a multiplier of 2 is applied to the Alloy 600 crack growth rate. Crack growth analysis is then conducted on a cycle-by-cycle basis to the end of service life. The crack growth rate equation for [ ]in light water environment to be used is then given by: da d--N = 2 C SRSg.J.v(AK)n Where AK is the stress intensity factor range in terms of MPa'Im and da/dN is the crack growth rate in terms of rn/cycle, and C = 4.835x10"' 4+ 1.622x10-T -1.490x10-' 8 T 2+ 4.355x10 2 1 T 3 Page 13 Controlled Document A A R EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary SR = [1 -- 0.82R]" 2" 2= 1 + A(C SR A~n)m'l TRl~rn A =4.4 x10-7 m --0.33 T = degrees C n=4.1 R =Kmin / Kmax TR. = rise time, set at 30 seconds 2.4 Fatigue Crack Growth Calculations For the flaw types postulated along paths 1la/b/c and 2a/b/c, the AREVACGC EXCEL based program, Reference[8.5], will be used to perform the fatigue crack growth calculation and estimate the final flaw size.For the cylindrical flaws postulated along paths 3 a/b/c and 4a/b/c, crack growths were estimated using EXCEL spread sheets. Crack growths for paths 3a/b/c and 4a/b/c are calculated by incrementally adding crack growth for one year at the time. Crack growth for one year is the summation of crack growth due to all transients for one year. Crack growth is incrementally linked such that the crack growth contribution from one transient is used to update the crack depth for the subsequent transient.

2.5 Acceptance

Criteria For postulated axial and circumferential flaws in the [ J repair weld the acceptance criteria in IWB-3 642, Reference [8.1] is used. IWB-3 642 states that "piping containing flaws exceeding the acceptance standards of LWB-35 14.1 may be evaluated using analytical procedures described in Appendix C and is acceptable for continued service during the evaluated time period when the critical flaw parameters satisfy the criteria in Appendix C." According to C-4230, Reference [8.1], for flaws in Ni-Cr-Fe weld metal, flaw evaluation procedures of C-42 10 shall be used. Based on Figure C-4210-1 of Reference [8.1 ], for a flaw in austenitic/Ni-Cr-Fe weld material that uses non-flux welds, Section C-5000, Reference [8.1 ], is to be used for flaw evaluation. For the postulated cylindrical flaw in the low alloy steel RVCH material, IWB-3612 acceptance criteria of Section XI, Reference [8.1] is used. According to IWB-3612 a flaw is acceptable if the applied stress intensity factor for the flaw dimension af- satisfy the following criteria.(a) For normal and upset conditions: KI <Kia/\'10 Where: K 1 = applied stress intensity factor for normal, upset, and test conditions for flaw dimension at.Kia = fracture toughness based on crack arrest for the corresponding crack-tip temperature af = end-of-evaluation-period flaw depth (b) For emergency, faulted, and test conditions: K 1<KKI /12 Page 14 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Where: K 1 = applied stress intensity factor for emergency, faulted, and test conditions for flaw dimension af.K 1 c = fracture toughness based on crack initiation for the corresponding crack-tip temperature af = end-of-evaluation-period flaw depth For the postulated cylindrical flaw in the [ ] weld repair material, IWB-3612 acceptance criteria is not evaluated since a limit load solution is not available for such a flaw in the ASME B&PV Code, Reference[8.1]. The shear stress at the remaining ligament for the maximum crack growth for this flaw type at the end of the plant life is evaluated per NB-3227.2, Reference [8.10].Page 15 Controlled Document A A R EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

3.0 ASSUMPTIONS

3.1 Unverified

Assumptions There are no unverified assumptions used herein. Justified assumptions and modelling simplifications are detailed in the following sections.3.2 Justified Assumptions 3.2.1 The anomaly is postulated to include a "crack-like" defect, located at the upper and lower "triple-point" locations. For analytical purposes, a continuous circumferential flaw is located in the horizontal plane. Another continuous flaw is located in the cylindrical plane between the weld and RVCH.3.2.2 In the radial plane, the anomaly is assumed to include a quarter-circular "crack-like" defect. For analytical purposes, a semi-circular flaw is used to represent the radial cross-section of the anomaly.3.2.3 In the interface of IDTB weld and RVCH bore, the anomaly is assumed to include a cylindrical-flaw like defect. For analytical purposes, a flaw in a semi-infinite plate is used to represent the radial cross-section of the anomaly.3.2.4 The CRDM housing nozzles function as mechanical mounts for the CRDM. The CRDM are relatively tall, slender structures that may be subjected to seismic or other motions resulting in bending loads on the 'CRDM nozzle-to-head connection' weld. However, mechanical loads from the CRDM are transmitted to the head through the interference fit region. The design feature effectively shields the 'CRDM nozzle-to-head connection' weld from being subject to external loads. Therefore, external loads are not applicable to the CRDM nozzle weld repair. The same justified assumption applies to the RVLIS and CETC Nozzles. No external loads are considered on the existing nozzle which extends above the RVCH top surface.3.3 Modelling Simplifications

3.3.1 Dimensions

used for the analyses are based on nominal values. This is considered to be standard practice in stress analysis and fracture mechanics analysis.Page 16 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

4.0 DESIGN

INPUTS The regions of interest for the present flaw evaluations are the upper and lower triple point locations, where three different materials intersect. These materials are the existing or the replacement Nozzle material, thle new llDTB repair weld material and the RVCH material. The Byron/Braidwood existing Nozzle is made of SB- 167 Alloy 600 material, the replacement nozzle is made of SB-166 Alloy 690, the new weld is made of [ ], and the RVCH is fabricated of SA-533 Grade B Class 1, Reference [8.2].4.1 Geometry Pertinent geometry parameters used for flaw evaluations are provided below: Paths la/b/c & 2a/b/c: The following dimensions are used for evaluating the 3600 circumferential flaw and axial flaw postulated along paths la/b/c & 2a/b/c. Dimensions obtained from Reference [8.7] bounds the dimensions from CRDM and RVLIS IDTB weld, Reference [8.12].Existing Nozzle/Bore OD =[Existing Nozzle ID =[ ] in Path l a/b/c Thickness, t 1 = [Replacement Nozzle OD =[Repair Nozzle ID at IIDTB Weld =Path 2a/b/c Thickness, t 2 = [Initial flaw depth, ai = 0.1 in]in] in]in] in Reference [8.7]Reference [8.7]Reference [8.7] -See Note 20 and Diameter "Dl"] in Reference [8.8]Reference [8.2]Paths 3a/b/c & 4a/b/c: The cylindrical flaws postulated along paths 3 a/b/c and 4a/b/c propagate along the interface between the IDTB repair weld and the RV Closure Head. The controlling length of this interface is 1.28 inches at paths 3 a/b/c and 4a/b/c, References [8.7] and [8.12]. The initial flaw depth is postulated to be 0.1 inches, Reference [8.2].4.2 Material Strength Reference [8.3] provides the material strength pertinent for the flaw evaluation assessment of the weld anomaly in this document. Table 4-1 lists the values of yield strength (cry) and ultimate strength (ault).Page 17 Controlled Document A A R E VA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle iDTB Repair Weld Anomaly -Non Proprietary Table 4-1 -Material Strength Matril omonnt Temp. Yield Strength, asy Ultimate Strength, {$ult Material______Component_____ (OF) (ksi) (ksi)RVCH m m SA-533 Gr. B Cl. 1 Weld Filler [ ]Equivalent SB- 166 IDTB Weld Alloy 690 properties Note (1): Interpolated values.4.3 Fracture Toughness 4.3.1 Low Alloy Steel RV Head Material The maximum nil ductility temperature (RTNDT) for the low alloy steel RVCH is [ ] for Byron Unit 1, Reference [8.11]. Fracture toughness curves for SA-533 Grade B Class 1 material is illustrated in Figure A-4200-1 of Reference [8.1]. At an operating temperature of about [ ] Reference [8.3], the Kia fracture toughness values for this material is (using RTNDT of [ ])are above 200 ksi~lin. An upper bound value of 200 will be conservatively used for the present flaw evaluations. 4.3.2 [ ] Material Brittle fracture is not a credible failure mechanism for ductile materials such as [ ] the failure mechanism for the [ ] materials is limit load or ductile crack extension (EPFM). IWB-3612 acceptance criteria for the cylindrical flaw postulated in the repair weld are not evaluated since a limit load solution is not available for such a flaw in the ASME B&PV Code, Reference [8.1]. The shear stress at the remaining ligament for the maximum crack growth in the [ ] weld repair material at the end of the plant life is evaluated per NB-3227.2, Reference [8.10].4.4 Applied Stresses Intensity Factor Calculation As mentioned in Section 2.2, the weight function method implemented in AREVACGC, Reference [8.5] was used to calculate the SIF for the OD continuous circumferential and axial surface flaws. For the cylindrical flaw, the SIF solution given in Appendix A of the 2001 Edition of Section XI, Reference [8.11 was used to calculate the SIW solution.4.4.1 Transient Stresses The cyclic operating stresses that are needed to calculate fatigue crack growth are obtained from a thermo-elastic finite element analysis, Reference [8.3]. These cyclic stresses are developed for all the transients at a number of time points to capture the maximum and minimum stresses due to fluctuations in pressure and temperature. Per References [8.3], the number of RCS design transients is established for 40 years of design life. Cyclic operating stresses were generated in Reference [8.3] for the transients listed in Reference [8.4]. The transients that have trivial contribution to fatigue are not considered per Reference [8.3]. The transient cycle counts used in this calculation are obtained from Reference [8.4]. The operating transients are listed in Table 4-2.All radial paths go from ID to OD of the IIDTB weld; all the vertical paths go from bottom to top. Stresses are provided for 12 equidistant intervals along the path lines.Page 18 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzie IDTB Repair Weld Anomaly -Non Proprietary Table 4-2 -Operating Transients and Cycles Condition Transient File Name Convention Number of Cycles Normal Upset Emergency Faulted Test Upset Page 19 Controlled Document A A R EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

4.4.2 External

Loads The CRDM housing nozzles function as mechanical mounts for the CRDM. The CRDM are relatively tall, slender structures that may be subjected to seismic or other motions resulting in bending loads on the 'CRDM nozzle-to-head connection' weld. However, mechanical loads from the CRDM are transmitted to the head through the interference fit region. The design feature effectively shields the 'CRDM nozzle-to-head connection' weld from being subject to external loads. Therefore, external loads are not applicable to the CRDM nozzle weld repair.The same justified assumption applies to the RVLIS and CETC Nozzles. No external loads are considered on the existing nozzle which extends above the RVCH top surface.4.4.3 Replacement Nozzle Loads Loads at the existing J-groove weld due to loads on the nozzle inside the vessel are supplied in PWROG-14067, Reference [8.4] and shown in Table 4-3. These will be referred to as 'Internal' loads to avoid confusion with loads occurring outside the vessel. The new repair nozzle is secured by the IDTB weld. Therefore, these same loads will be used to determine the stress distribution acting on the path lines due to loading from inside the vessel. [ ]cycles of OBE seismic loading, per TODI-BYR-15-0 12, Reference [8.4], will be considered. Table 4-3 -Replacement Nozzle Internal Mechanical Loads Load Description Axial (ibs) Shear (ibs) Moment (in-lbs)Deadweight Flow-Induced Vibration +Pump-Induced Vibration OBE ______________ The effect of deadweight and flow/pump induced vibration loads is addressed by adding these loads as additional stresses to the transient and residual stresses for fatigue crack growth evaluation in AREVACGC, Reference [8.5].Seismic effects are addressed as described in Section 4.4.4.4.4.4 Seismic Event The effect of the seismic OBE loads on fatigue crack growth is addressed by modeling the seismic event as a transient event. The OBE loads as obtained from Reference [8.4] acting on the path lines are shown in Table 4-3.These OBE loads are converted to axial stresses according to AxialStres ia Mbending Axia Stess A S 0 Where So is the OD section modulus conservatively used in the calculation. The results are given in Table 4-4.Page 20 Controlled Document A A R EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 4-4 -Axial Stresses due to Seismic Loads Path Line ORE(+-) la/lb/lc 2a/2b/2c Axial Stress, psi [ [ ]The baseline through-wall axial stress distribution for each path line is obtained from the stress state at the steady state conditions. This corresponds to the last time point of transient HUR. Per TODI-BYR-15-0 12, Reference [8.4], the total lifetime number of OBE cycles is [ ]4.4.5 Residual Stresses A three-dimensional elastic-plastic finite element analysis, Reference [8.9] was performed to simulate the sequence of steps involved in arriving at the configuration of the weld repair of CRDM/RVLIS/CETC Nozzle in the RVCH of Byron/Braidwood Units 1 and 2. The residual stress analysis, Reference [8.9], simulated welding of the existing J-groove weld and butter; machining of the nozzle and IDTB weld prep; attaching Alloy 690 replacement nozzle; welding of the IDTB weld repair with [ ] Operation at steady state temperature and pressure conditions and retumn to zero load conditions was also simulated after the completion of the weld simulation. The residual stresses are provided by Reference [8.9] for the path lines identified in Figure 2-1. All radial paths go from GD to ID of the IDTB weld; all the vertical paths go from top to bottom. Stresses are provided for 20 equidistant intervals along the path lines. Since transient stresses provided in Reference [8.3] are provided for 12 equidistant intervals along the path lines, residual stresses are mapped to 12 equidistant intervals and to go from ID) to GD of the IDTB weld (radial paths) and from bottom to top (vertical paths) to match stress distribution from Reference [8.3]. Weld residual stresses are linearly added to the transient stresses.Page 21 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

5.0 CALCULATIONS

Assessment of a flaw like triple point anomaly in the Byron/Braidwood Nozzle repair was completed using three flaw types that were postulated to form in the vicinity of the triple point. For every postulated flaw type a crack growth analysis was conducted to determine the final flaw size after 40 years of operation. After the final flaw size is determined, the flaw is assessed to determine the safety margins and compliance with the flaw acceptance criteria outlined in Section 2.5.5.1 Circumferential Flaw for Paths lalb/c & 2alb/c 5.1.1 Circumferential Flaw Growth Analysis (Paths la/b/c and 2a/b/c)AREVACGC, Reference [8.5] was used to determine the final flaw depth due to fatigue crack growth. A summary of the final flaw depths is given in Table 5-1 for paths la, lb, lc, 2a, 2b and 2c. Contribution of the individual transients to crack growth is given in Table 5-2 for paths la, lb, 2a, and 2b and in Table 5-3 for paths lc and 2c.Table 5-1 -Crack Growth for 3600 Circumferential Flaw (Paths la/b/c and 2a/b/c)Path Path la Path lb Path lc Path 2a Path 2b Path 2c Initial Flaw Depth (in) = 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 Initial a/t ratio=Final Flaw Depth (in) =Final a/t ratio=Total amount of Fatigue Crack Growth (in) =Page 22 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-2 -Individual Transient Contribution to Crack Growth for 3600 Circumferential Flaw (Paths lalb and 2a/b)Path Path la Path lb Path 2a Path 2b Transient Growh. Peret Grwh. Percent Growth,. ecn Growth,. ecn Page 23 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-3 -Individual Transient Contribution to Crack Growth for 3600 Circumferential Flaw (Paths Ic and 2c)Path Pathilc Path 2e..... Growth IPercent Growth ......5.1.2 Flaw Evaluation for OD Circumferential Flaw (Paths lalblc & 2alblc)As mentioned in Section 2.5, Article C-5000 of Reference [8.11 contains the appropriate flaw evaluation procedure for the end of life OD circumferential flaw. As shown in Table 5-1, since the final flaw depth along path 2a is the greatest between the other paths, the final flaw depth for path 2a is used for the end of life flaw evaluation and conservatively using the dimensions of paths la/b/c which have the smallest thicknesses. Table 5-4 shows details of the end of life flaw evaluation analysis performed to assess the postulated continuous circumferential flaw. It is seen from Table 5-4 that the allowable stress is higher than the applied membrane stress by 3.38 times safety factor.Page 24 Controlled Document A A RE VA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-4 -End of Life Evaluation for Continuous External Circumferential Flaw (Limit Load)Yield Strength, Cy [ Jksi Ultimate Strength, 0[ [ J ksi Pressure, p = [ J psi Outside Radius, R 0 = [ ] in Inside Radius, R 1 = [ ] in Mean Radius, Rm = [ ] ifl Thickness, t = [ ] in Final Flaw Depth, af = [ ] in Cm=pDo/4t= [ ] ksi Flow strength, ocf = [ ] ksi Safety Factor, SFm~ = 2.7 0= 3.1416 rad Crc= Gf/ [1-(a/t)(0/it)-2(p/t] = [ ] ksi (p = arcsin[O.5(a/t)sin0] = 0 rad Margin, St/(Gm = [ ]5.2 Axial Flaw for Paths lalb/c & 2alb/c 5.2.1 Axial Flaw Growth Analysis (Paths lalblc & 2a/blc)AREVACGC, Reference [8.5] was used to determine the final flaw depth due to fatigue crack growth. For each path (la/b/c & 2a/b/c) crack growth was performed using depth location (radial) and surface location (axial) SIF.A summary of the final radial and axial flaw depths is given in Table 5-5 and Table 5-6, respectively, for paths 1la, ib, 1lc, 2a, 2b, and 2c. Contribution of the individual transients to radial and axial crack growth is given in Table 5-7 and Table 5-8, respectively for paths la, lb, 2a, and 2b and in Table 5-9 and Table 5-10 for paths ic and 2c.Table 5-5 -Radial Crack Growth for Axial Flaw Path Path la Path lb Path lc Path 2a Path 2b Path 2e Initial Flaw Depth (in) = 0.1000 0.1000 0.1000 0.1000 0.1000 0.1000 Initial a/t ratio =Final Flaw Depth (in)=_Final a/t ratio =Total amount of Fatigue Crack Growth (in) = IIII Table 5-6 -Axial Crack Growth for Axial Flaw niilatrtoPath IPath la Path lb Path le Path 2a Path 2b Path 2c InitiaIlFlaw Depth (in) = 0.1000 0.1000 0.1000 ,0.1000 0.1000 0.1000 Final Flaw Depth (in) =_Total amount of Fatigue Crack Growth (in) Fnlatrio=L Page 25 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzie JDTB Repair Weld Anomaly -Non Proprietary Table 5-7 -Individual Transient Contribution to Radial Crack Growth for Axial Flaw (Paths lalb and 2a/b)Path Path la Path lb Path 2a Path 2b Transient Growth Pret Growth Pret Growth IPret Growth Pecn Page 26 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-8 -Individual Transient Contribution to Axial Crack Growth for Axial Flaw (Paths lalb and 2alb)Path Path la Path lb Path 2a Path 2b Transient Gr..t Percent Gr.wt Percent Gr..h Percent Gr.wt Percent Page 27 Controlled Document A ARE VA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-9 -Individual Transient Contribution to Radial Crack Growth for Axial Flaw (Paths Ic and 2c)Path Path lc Path 2c Transient Gr.wt Percent Groth. Percent Page 28 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-10 -Individual Transient Contribution to Axial Crack Growth for Axial Flaw (Paths 1c and 2c)Path I Path lc I Path 2c 5.2.2 Flaw Evaluation for OD Axial Flaw (Paths lalblc & 2alblc)As mentioned in Section 2.5, Article C-5000 of Reference [8.1] contains the appropriate flaw evaluation procedure for the end of life OD axial flaw. As shown in Table 5-5 and Table 5-6 the maximum flaw depth is[ ] for a flaw along path 2a considering an axial crack growth of [ ] This flaw depth was used for the end of life flaw evaluation of the postulated OD axial flaw. Table 5-11 shows details of the end of life flaw evaluation of the postulated OD axial flaw. It is shown in Table 5-11, that both the final flaw depth and length, after 40 years of crack growth, are less than the allowable flaw depth and length.Page 29 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-11 -End of Life Evaluation for External Axial Flaw (Limit Load)Yield Strength, Ultimate Strength, 0 ult =Flow strength, of Pressure, p =Outside Radius, Ro Inside Radius, Ri Mean Radius, Rm Thickness, t =Final Flaw Depth, af =Final Flaw Length, If = 2 x af =( =pRm/t=lallow = 1.5 8(Rmt)°'5 [(a3f/aYh) 2-l]0.5 =Ma= [1 + (1.61 / 4Rmt)lf 2)]°'5 Safety Factor, SFm=Stress Ratio = SFm OhiO(Y =Nondimensional Flaw Length, lf/hIRmt =Allowable a/t Allowable Flaw Depth, a~1 ow =Margin, a~o / af =[ )[ ][ )[ )[ )[ I[ I[ )2.7[ ][ ][ I[ )ii'ksi ksi ksi psi in in in in in in ksi in2 Table C-5410-1, Reference [8.1 ]5.3 Cylindrical Flaw for Paths 3alb/c & 4alblc 5.3.1 Cylindrical Flaw Growth Analysis (Paths 3ab/bc & 4a/blc)For the cylindrical flaws, crack growth was calculated in accordance with Section 2.4. Crack growth for first year is shown in Table 5-12 through Table 5-23 for paths 3a, 3b, 3c, 4a, 4b, and 4c, respectively. Final crack depths for the cylindrical flaws for all paths are shown in Table 5-24 and Table 5-25.Page 30 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-12 -First Year Crack Growth for Cylindrical Flaw along Path 3a (Bottom Corner)Kmax Kmin AK AN Aa = AN Co(AK)a Taset (ksi~Jin) (ksi'Iin) (ksi~Iin) (cycle/year) (in)Page 31 Controlled Document A ARE EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-13 -First Year Crack Growth for Cylindrical Flaw along Path 3b (Bottom Corner)[ Kmiax Kmin AK I AN IAa =AN Co(AK)"I Page 32 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-14 -First Year Crack Growth for Cylindrical Flaw along Path 3c (Bottom Corner)Kmex Kmin AK AN Aa = AN Co(AK)n Taset (ksi'lin) (ksi~in) (ksi~1in) (cycle/year) (in)K Page 33 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-15 -First Year Crack Growth for Cylindrical Flaw along Path 4a (Bottom Corner)F.. ..1 Kmax IKmin AK " AN Aa =AN Co(AK)"]Page 34 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-16 -First Year Crack Growth for Cylindrical Flaw along Path 4b (Bottom Corner)Kmax Kmin AK AN Aa = AN Co(AK)" Transient (ksi~Iin) (ksi'lin) (cycle/year) (in)Page 35 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-17 -First Year Crack Growth for Cylindrical Flaw along Path 4c (Bottom Corner)Kmax Kmin AK AN Aa = AN Co(AK)" Taset (ksi'lin) (ksi'lin) (cycle/year) (in)Page 36 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-18 -First Year Crack Growth for Cylindrical Flaw along Path 3a (Top Corner)Kmax Kmin AK AN Aa = AN Co(AK)n Transient (ksiIin) (ksi~in) (ksi'~in) (cycle/year) (in)Page 37 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-19 -First Year Crack Growth for Cylindrical Flaw along Path 3b (Top Corner)Kmax Kmin AK AN Aa = AN Co(AK)n Taset (ksi~Iin) (ksilin) (cycle/year) (in)Page 38 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-20 -First Year Crack Growth for Cylindrical Flaw along Path 3c (Top Corner)Kmax Km 1 1 1 AK AN Aa = AN Co(AK)" Taset (ksi~Iin) (ksi~in) (ksi~Iin) (cycle/year) (in)Page 39 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-21 -First Year Crack Growth for Cylindrical Flaw along Path 4a (Top Corner)Kmax Kmi. AK AN Aa = AN Co(AK)" Transient (ksi'lin) (ksi~in) (cycle/year) (in)I I Page 40 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-22 -First Year Crack Growth for Cylindrical Flaw along Path 4b (Top Corner)Kmax Kmin AK AN Aa = AN Co(AK)" Transient (ksi~Iin) (ksi'Iin) (cycle/year) (in)Page 41 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-23 -First Year Crack Growth for Cylindrical Flaw along Path 4c (Top Corner)Kmax Kmin AK AN Aa -ALN Co(AK)n Transient (ksi~in) (ksi~in) (ksidin) (cycle/year) (in)Table 5-24 -Final Crack Depth for Cylindrical Flaw (Bottom Corner)Path Crack Depth (in)Path 3a Path 3b Path 4a []Path 4b ]Path 4c Table 5-25 -Final Crack Depth for Cylindrical Flw(Top Corner)Path Crcack Depth (in)Path 3a Pat [3 Path 3c .ff ]Path 4a []Path 4b fi [ i]Path 4c []Page 42 Controlled Document A ARE EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

5.3.2 Fracture

Toughness Margin for Cylindrical Flaw (Paths 3a/blc & 4alblc)As mentioned in Section 2.5, for the postulated cylindrical flaw in the low alloy steel RV closure head material, IWB-3612 acceptance criteria of Section XI, Reference [8.1] is used. According to IWB-3612, a flaw is acceptable if the applied stress intensity factor for the flaw dimension af satisfy the criteria that K 1 < KIa /410 for normal/upset conditions and K 1 <KK~ /42 for emergency/faulted/test conditions. To determine the fracture toughness margin, the maximum applied stress intensity factor for all time points is determined for each flaw path. The effective Stress intensity factor is then determined based on the theory in Reference [8.1]. The temperature (T) is the minimum (limiting) temperature of each transient. The minimum temperatures of most limiting transients are shown along with corresponding Kia'S are shown in Table 5-26. In Table 5-26, it is shown that the calculated minimum LEFM margins are [ ] for service level A and B and[ ] for Emergency/Faulted/Test Conditions, and are thus higher than the required margin of 4i10 (Level A &B) and 4/2 (Level C & D), respectively. For the postulated cylindrical flaws in the [ ] weld repair material, IWB-3612 acceptance criteria is not evaluated since a limit load solution is not available for such a flaw in the ASME B&PV Code, Reference[8.1 ]. The shear stress at the remaining ligament for the maximum crack growth for this flaw type at the end of the plant life is evaluated below per NB-3227.2, Reference [8.10].Page 43 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 5-26 -LEFM Margin for Cylindrical Flaw Pt&Loain Limiting ar Kleff Temp. Kia Margin Pt&Loain Transients (in) (ksi'/in) (°F) (ksi'in) Kia / Kieff Path 4a (Head Bottom) __Path 4b (Head Bottom) __Levels Path 4c (Head Bottom) __>31 A/ B Path 4a (Head Top) __Path 4b_(Head Top) __Path 4c_(HeadTop) _____________________________ ___K 1 c Margin (ksi'Iin) Kia / Kieff Path 4a (Head Bottom)Path 4b (Head Bottom)Levels Path 4c (Head Bottom)>14 C/ D/ ->14 Test Path 4a (Head Top)Path 4h (Head Top)Path 4c_(Head Top) _____________________________ ___Notes (1): Kciof < 0 and therefore there is no crack growth for service level.The shear stress at the remaining ligament is also calculated as follows: t: (Paxial _H + Paxial_intcnal)/(As) Where: PaxiiH = (it/4) x P x D 0 2 = (it/4)ea~alInternal = [ ]As=2 x it x [Lrm~a x D/2 ][Reference [8.3]Table 4-3 Where Lrma is the remaining ligament of the IDTB weld/head interface after crack growth at paths 3a, 3b, 3c, 4a, 4b, and 4c. The maximum crack growth among cracks along paths 3a, 3b, 3c, 4a, 4b, and 4c is for path 4b at the bottom corner and the final flaw size is [ ] (Table 5-24). Thus the area of the remaining ligament is found as As= [Thus the shear stress, T = (PayjiaH + Paxial~ntenma)/(As) = [1 Per NB-3227.2, Reference [8.10], the maximum allowable average primary shear stress in IDTB weld is 0.6Sin, which equals 13.98 ksi (with Sm equal to 23.3 ksi, Reference [8.3]). Therefore the remaining ligament of the IDTB weld has a lower shear stress than allowable shear stress.Page 44 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

6.0 RESULTS

The flaw evaluation results for 40 years of fatigue crack growth are as follows.6.1 Fatigue Crack Growth of Continuous External Circumferential Flaw a) Fatigue crack growth analysis: Initial flaw size, a 1 = 0.1000 in.Final flaw size, ar = [b) End of Life (Limit load) analysis:]Margin,[]6.2 Fatigue Crack Growth of Semi-Circular External Axial Flaw a) Fatigue crack growth analysis: Initial flaw size, ai 0.1000 in.Final flaw size, af = [b) End of Life (Limit load) analysis: Margin,[]6.3 Fatigue Crack Growth of Continuous Cylindrical Flaw along Paths 3a & 4a RVCH (Path 4a Bottom Tip')Initial flaw size, ai = 0.1000 in.Final flaw size, ar [Level A and B Stress intensity factor at final flaw size, KIeff [Level A and B Fracture toughness, KIa =[Level A and B Fracture toughness margin, Kia 'Kieff = []] > 410 1>4 Level C, D, and Test Stress intensity factor at final flaw size, Level C, D, and Test Fracture toughness, Level C, D, and Test Fracture toughness margin, RVCH (Path 4a Top Tip)Initial flaw size, Final flaw size, Level A and B Stress intensity factor at final flaw size, Level A and B Fracture toughness, Level A and B Fracture toughness margin, Level C, D, and Test Stress intensity factor at final flaw size, Level C, D, and Test Fracture toughness, Level C, D, and Test Fracture toughness margin, Kleff-= [Ki 0= [Kic / Kieff=a 1 = 0.1000 in.af= [Kleff = [Kla Kieff= [Kqc= [Kic / Klerr= []] > 41o] >42 Page 45 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Nozzle/IDTB Weld (Path 3a Bottom Tip)Initial flaw size, Final flaw size, Max. Shear Stress, Nozzle/IDTB Weld (Path 3 a Top Tip)Initial flaw size, Final flaw size, Max. Shear Stress, ai = 0.1000 in.a f= [T= [1 < 0.6Sin= 13.98 ksi ai= 0.1000 in.af-=]] <O0.6Sm =13.98 ksi 6.4 Fatigue Crack Growth of Continuous Cylindrical Flaw along Paths 3b & 4b RVCH (Path 4b Bottom Tip)Initial flaw size, a 1 = 0.1000 in.Final flaw size, af = [Level A and B Stress intensity factor at final flaw size, Kleff [Level A and B Fracture toughness, Kia =Level A and B Fracture toughness margin, KIa ,"Kleft = []]]]i > `/1 Level C, D, and Test Stress intensity factor at final flaw size, Level C, D, and Test Fracture toughness, Level C, D, and Test Fracture toughness margin, RVCH (Path 4b Top Tip)Initial flaw size, Final flaw size, Level A and B Stress intensity factor at final flaw size, Level A and B Fracture toughness, Level A and B Fracture toughness margin, Level C, D, and Test Stress intensity factor at final flaw size, Level C, D, and Test Fracture toughness, Level C, D, and Test Fracture toughness margin, KIeff i Kic / KIeff= [ai= 0.1000 in.af= [KIeff=[Kia--[Kia/'K~ef = [K~c= [KIc / Kfr= [1 Nozzle/IDTB Weld (Path 3b Bottom Tip)Initial flaw size, Final flaw size, Max. Shear Stress, NozzlefIDTB Weld (Path 3b Top Tip)Initial flaw size, Final flaw size, Max. Shear Stress, ai= 0.1000 in.af= []t [ ] ksi <0.6Sin 13.98 ksi ai=0.1000 in.af= []1< 0.5m P13.9 ksi Page 46 A AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

6.5 Fatigue

Crack Growth of Continuous Cylindrical Flaw along Paths 3c & 4c RVCH (Path 4c Bottom Tip)Initial flaw size, ai 0.1000 in.Final flaw size, af = [Level A and B Stress intensity factor at final flaw size, =Level A and B Fracture toughness, Kia = [Level A and B Fracture toughness margin, KIa 'KIeff = [Level C, D, and Test Stress intensity factor at final flaw size, Level C, D, and Test Fracture toughness, Level C, D, and Test Fracture toughness margin, RVCH (Path 4c Top Tip)Initial flaw size, Final flaw size, Level A and B Stress intensity factor at final flaw size, Level A and B Fracture toughness, Level A and B Fracture toughness margin, Level C, D, and Test Stress intensity factor at final flaw size, Level C, D, and Test Fracture toughness, Level C, D, and Test Fracture toughness margin, KIeff ' [K~c = [Kic / Kieff = [a 1 = 0.1000 in.at`=[KIaKeff = [i~i KIeff = [Kici= C K~c I KIeff= []] >-'10]i >4/2 I] >4/10]>2 Nozzle/IDTB Weld (Path 3c Bottom Tip)Initial flaw size, Final flaw size, Max. Shear Stress, Nozzle/IDTB Weld (Path 3c Top Tip)Initial flaw size, Final flaw size, Max. Shear Stress, ai = 0.1000 in.at`-- [r= [ J ksi <0.6Sin 13.98 ksi a 1 = 0.1000 in.at`= [t= [ ] ksi<]0.6Sin = 13.98 ksi The results of the analysis demonstrate that a 0.10 inch weld anomaly is acceptable for a 40 year design life of the Byron/Braidwood RVCH CRDM/RVLIS/CETC Nozzle IDTB weld repair. The minimum fracture toughness margins for flaw propagation Paths 3a, 3b, 3c, 4a, 4b, and 4c have been shown to be acceptable as compared to the required margins of /10 for normal/upset conditions and -42 for emergency/faulted/test conditions per Section XI, rWB-36 12 (Reference [8.1]). A limit load analysis was performed considering the ductile weld repair material along flaw propagation Paths la/b/c and 2 a/b/c. The analysis showed that for the postulated circumferential flaw the minimum margin on allowable stress is [ I For the axial flaw the minimum margin on allowable flaw depth is [ ] Fracture toughness margins have been demonstrated for the postulated cylindrical flaws at the RVCH. Also for cylindrical flaws at the RVCH and the IDTB weld it is shown that the applied shear stress at the remaining ligament is less than the allowable shear stress per NB-3 227.2, Reference [8.10].Page 47 Controlled Document A A R EVA Document No. 32-9244389-000 Byron/Braidwood RVCGH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

7.0 COMPUTER

USAGE 7.1 Validation To validate the installation of AREVACGC 5.0, Reference [8.5], Test Case 1 provided in Reference [8.5](contained in TestCasel1.xls) was executed. The installation of the software on a PC workstation is documented below and verification tests of similar applications are listed as follows.* Computer programs tested: AREVACGC 5.0* Computer hardware used: The hardware platform is Intel (R) Core(TM) i7-3520M CPU at 2.90 GHz, 8GB RAM and the Operating System is Microsoft Windows 7, version 2009, Service Pack 1, Serial Number CRPMYW1.* Name of person running the tests: Luziana Reno* Date of tests: 03/24/2015.

• Acceptability:

Results agree with those documented for the corresponding test case in Reference [8.5].7.2 Computer Files Microsoft@ Office Excel, along with the Excel macro program AREVACGC version 5.0, is used in the crack growth and SIF calculation. All computer analyses were run on Microsoft Windows 7, version 2009, Service Pack 1. The hardware is Intel (R) Core(TM) i7-3520M CPU at 2.90 GHz, 8GB RAM.Computer files for all analysis contained in this document are listed in Table 7-1. These files have been stored in COLOSTOR server within the directory "\cold\General-Access\32\32-9000000\32-9237284-000\official." Page 48 Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Table 7-1 -Computer Files for Crack Growth Evaluation File Name Data and Time Size (bytes) Checksum Description Axial flaw evaluation with BB12_AxialSY(Hoop).xlsm 6/15/2015 09:07 1000598 57536 AREVACGC for paths la/b and 2a/b BB12_AxialSY(Hoop)_90Deg. 6/15/2015 08:55 650584 17809 Axial flaw evaluation with xlsm AREVACGC for paths ic and 2c Circumferential flaw evaluation BBl12_CircSZ(axial).xlsm 6/15/2015 08:33 805669 16224 with AREVACGC for paths la/b and 2a/b Circumferential flaw evaluation BB12_Circ_SZ(axial)_90Deg.xls 6/15/2015 08:41 510418 42160 with AREVACGC for paths ic and m 2c BB 12_EdgeP3a_bot.xls 6/15/2015 08:17 1970176 11615 Cylindrical Flaw Evaluation Path_______________________3a at Bottom Crack Tip B~l2dge~atp~xs 49/2 15 :57 2,58,80 5764 Cylindrical Flaw Evaluation Path BB12EdgP~~topxls4/920159:5 2,08,80 5764 3a at Top Crack Tip BB12 EdgeP3b bot.xls 6/15/20 15 08:17 1912320 38861 Cylindrical Flaw Evaluation Path-_____-_____- _____3b at Bottom Crack Tip BB lEdgP~bop~ls 49/2 159:5 2,45,32 1424 Cylindrical Flaw Evaluation Path BB 1_EdeP~~to~xls4/9201 9:5 2,45,32 1424 3b at Top Crack Tip BB 1 EdeP~cbotxls /1520 5 0817 53600 2204 Cylindrical Flaw Evaluation Path BB_12_Eg_P~_ botxls_6/15/2015_08:17_1536000_2520 3c at Bottom Crack Tip BB lEdgP~cop~ls 49/2 159:5 1,61,56 2300 Cylindrical Flaw Evaluation Path BB 1_EdeP~~to~xls4/9201 9:5 1,01,56 2300 3c at Top Crack Tip BB12Edg P~abotxls /1520 5 0817 07464 0047 Cylindrical Flaw Evaluation Path__B_12_Eg_P~_ botxls_6/15/2015_08:17_2074624 0004 4a at Bottom Crack Tip BB 12_EdgeP4a~top.xls 4/1/20 15 15:45 2,436,608 05932 ClnrclFa vlainPt_____________________ _____________4a at Top Crack Tip BB 1 Ede Pb bt~xs 615/2 1508:2 27058 0304 Cylindrical Flaw Evaluation Path BB__12_Ede~_ botxls_6/15/2015_08:12_2070528_0330 4b at Bottom Crack Tip B~l2dge~btp~xs 4//2015 5:4 2,43,92 2849 Cy'lindrical Flaw Evaluation Path BB12EdgP~btopxls /1/01515:4 2,93,92 2849 4b at Top Crack Tip BB12Edg P~cbotxls /1520 5 0817 54162 3030 Cylindrical Flaw Evaluation Path BB12_ EgeP_ _ bot__ ls_6/15/2015_8:17_1541632_3303 4c at Bottom Crack Tip B~l2dge~ctp~xs 4//2015 5:4 1,68,12 3263 Cylindrical Flaw Evaluation Path BB12EdgP~ctopxls /1/01515:4 1,08,12 3263 4c at Top Crack Tip 4/2/015 0:03 413,84 5845 Verification of Kleff edge Kl~edgeVerification.xls 4//21c1:3i1,14 514 TestCasel.xls 3/24/2015 10:19 628,736 64581 Test case for verifying that____________________ ________AREVCGC

5.0 executes

properly Test case for verifying that TestCasel1 15-2015.xls 6/15/2015 09:10 628736 40837 AREVCGC 5.0 executes properly_______________________________________________after all runs were completed Page 49 Controlled Document A A R EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary

8.0 REFERENCES

8.1 ASME Boiler and Pressure Vessel Code, Section XI, "Rules for Inservice Inspection of Nuclear Power Plant Components", 2001 Edition with 2003 Addenda.8.2 AREVA Document 08-9232121-000, Specification, "Byron Units 1 and 2, and Braidwood Units 1 and 2, RVCH Nozzle and Penetration Modification" 8.3 AREVA Document 32-9233803-000, "ASME Section III Analysis of Byron/Braidwood RVCH Nozzle and Penetration Modification" 8.4 AREVA Document 38-2201373-000, "Byron Units 1 and 2 and Braidwood Units 1 and 2 Proprietary Information" 8.5 AREVA Document 32-9055891-006, "Fatigue and PWSCC Crack Growth Evaluation Tool AREVACGC" (Proprietary Document)8.6 NUJREG/CR-6907, "Crack Growth Rates of Nickel Alloy Welds in a PWR Environment", U.S.Nuclear Regulatory Commission (Argonne National Laboratory), May 2006 8.7 AREVA Drawing 02-9232824E-000, "Byron Units 1 and 2/Braidwood Units 1 and 2 Thermocouple Column Penetration Modification" 8.8 AREVA Drawing 02-9232827D-000, "Byron Units 1 and 2/Braidwood Units 1 and 2 Replacement Thermocouple Housing Extension"~

8.9 AREVA

Document 32-9233779-000, "Weld Residual Stress Analysis of Byron 1 & 2, and Braidwood 1 & 2 RVCH Nozzle/Penetration Repair" 8.10 ASME Boiler and Pressure Vessel Code, Section III, "Nuclear Facility Components", Division 1, 2001 Edition with 2003 Addenda.8.11 AREVA Document 51-9234885-000, "Exelon Byron and Braidwood RVCH Original Material and Fabrication Review" 8.12 AREVA Drawing 02-9232823E-000, "Byron Units 1 and 2/Braidwood Units 1 and 2 CRDM, Spare,& RVLIS Penetration Modification" Page 50 Ak AR EVA Controlled Document Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary APPENDIX A: VERIFICATION OF SIF FOR CYLINDRICAL FLAW This Appendix provides verification of the Excel macro Kleff_edge used to calculate the SIF intensity factor for the cylindrical flaw which considers plasticity correction. The test case considered in this Appendix used ao = 0.05 inch, t = 0.5 inch, a/l = 0, and ay 41.45 ksi.Basis: Analysis of Flaws, 2001 through 2003 Addenda ASME Code, Section XI, Appendix A, Reference [8.1]K 1=[ A 0 Go + A 1 G 1+ A 2 G 2+ A 3 G 3] J/ita/Q)where and Q = 1 + 4.593 (a/l)1'6 5 -q qy =[ (A 0 Go + A 1 G 1+ A 2 G 2+ A 3 G 3) /~ j 2 / 6 For a/l 0.0 a/t_<0.1 (continuous flaw)Go 0= 1.195 G =O0.773 G 2 =0.600 G 3=0.501 Stresses are described by a third order polynomial fit over the flaw depth, S(x) =A 0 + A 1 (x/a) + A 2 (x/a)2 + A 3 (x/a)3 For the following given residual and transient stresses: Wall Position, x Residual Stress Transient Stress Total Stresses (in) (ksi) (ksi) (ksi)0.000 12.73 0.132 12.859 0.042 14.70 0.131 14.826 0.083 16.66 0.129 16.792 0.125 16.48 0.127 16.603 0.167 16.29 0.123 16.412 0.208 16.13 0.118 16.248 0.250 15.97 0.116 16.082 0.283 17.28 0.104 17.382 0.333 18.59 0.092 18.678 0.375 17.08 0.078 17.157 0.417 15.57 0.043 15.615 0.458 28.48 -0.029 28.453 0.500 41.39 -0.2940 41.100 Page A-I Controlled Document A AR EVA Document No. 32-9244389-000 Byron/Braidwood RVCH Nozzle IDTB Repair Weld Anomaly -Non Proprietary Stress over crack face: x/a Interpolated 0.00 0.000 12.859 A 3 = 0.048207 0.10 0.005 13.093 A 2 = -0.05433 0.20 0.010 13.327 A 1 = 2.356546 0.30 0.015 13.562 Ao = 12.85844 0.40 0.020 13.796 0.50 0.025 14.030 0.60 0.030 14.264 0.70 0.035 14.498 0.80 0.040 14.732 0.90 0.045 14.970 1.00 0.050 15.210 qy =[(AoGo + A 1 G 1 + A 2 G 2 + A 3 G 3)/Gy ]2 / 6 = 0.029 PlatictyQ = 1 + 4.593 (a/i)1'6 5 -qy~ = 0.971 Correction K, = [AoGo + AG, + A 2 G 2 + A 3 G 3] qI(ita/Q) = 6.906 Kleff_edge = 6.906 Difference = 0.0%Page A-2}}