ML25294A150

Enclosure 2: Non-Proprietary Documents

ML25294A150
Person / Time
Site:	Callaway
Issue date:	10/21/2025
From:	Framatome
To:	Office of Nuclear Reactor Regulation
Shared Package
ML25294A147	List: ML25294A148 ML25294A150 ULNRC-06976, Enclosure 3: Affidavits for Proprietary Documents
References
ULNRC-06976 32-9393028-003, 51-9392748-003, 32-9392644-003
Download: ML25294A150 (1)

Text

Enclosure 2 to ULNRC-06976 Non-Proprietary Documents 32-9393028-003, "Callaway BMI Nozzle One-Cycle Justification Section III Analysis" (57 pages) 51-9392748-003, "Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs" (31 pages) 32-9392644-003, "Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35, and 57" (24 pages)

Controlled Document 0402-01-F01 (Rev. 023, 06/20/2024) framatome CALCULATION

SUMMARY

SHEET (CSS)

Document No.

32-9393028-003 Safety Related:

& Yes

© No Title Callaway BMI Nozzle One-Cycle Justification Section III Analysis PURPOSE AND

SUMMARY

OF RESULTS:

REV 000 PURPOSE:

The purpose of this calculation is to qualify the Callaway #48 Reactor Vessel Bottom Mounted Instrument Nozzle half-nozzle repair for one cycle of operation according to the ASME B&PV Code Section III requirements (Ref. [1]).

REV 001 PURPOSE:

The purpose of Revision 001 is to add qualification of penetrations #30 and #35 in accordance with ASME B&PV Code Section II! requirements (Ref. [1]), in addition to the previously qualified penetration #48.

- REV 002 PURPOSE:

The purpose of Revision 002 is to add qualification of penetration #57 in accordance with ASME B&PV Code Section Ill requirements (Ref. [1]), in addition to the previously qualified penetrations #48, #30, and #35.

REV 003 PURPOSE:

The purpose of Revision 003 is to re-analyze qualifications of penetrations #48, #30, #35 and #57 due to re-design of the J-weld preparation on the downhill side per (Ref. [15]) in accordance with ASME B&PV Code Section III requirements (Ref. [1]).

REV 004 PURPOSE:

The purpose of Revision 004 is to revise proprietary markings and correct typographical errors.

REV 005 PURPOSE:

The purpose of Revision 005 is to remove proprietary brackets associated with the 18-month cycle of operation.

_ REV 005

SUMMARY

OF RESULTS:

The calculation herein demonstrates the half-nozzle repairs for Callaway #48, #30, #35 and #57 Reactor Vessel Bottom Mounted Instrumentation Nozzle satisfy the applicable requirements of the ASME B&PV Code (Ref. [1]) for one cycle of operation.

Proprietary information in the document is identified by bold brackets ([]). The content of this document is identical to 32-9392552-005, except that proprietary information is redacted. Any Rev. 001, Rev. 002, Rev. 003, Rev. 004, or Rev. 005 herein refers to that in 32-9392552. Although this non-proprietary version is Rev. 003, the proprietary version is Rev. 005.

Export Classification USEC:

ON gPart810 GEAR ECCN:

NA If the computer software used herein is not the latest version per the EAS list, AP 0402-01 requires thatjustification be provided.

THE DOCUMENT CONTAINS THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:

ASSUMPTIONS THAT SHALL BE VERIFIED PRIOR TO USE CODE/VERSION/REV CODE/VERSION/REV SCIPYENV 2024.07.3 Yes XX! No Page 1 of 57

Controlled Document 0402-01-F01 (Rev. 023, framatome Rev. 023, Document No. 32-9393028-003 Callaway BMI Nozzle One-CycleJustification Section III Analysis Review Method: [X] Design Review (Detailed Check)

[l Alternate Calculation Does this document establish design or technical requirements?

[ ] YES NO Does this document contain Customer Required Format?

[l YES NO Signature Block Name and Title Signature and Date Role Scope/Comments CR MANDEL Cayla Mandel, 9/24/2025 All changes made in Revision 5 Engineer He Jasmine Cao,

_ MJ CAO Advisory Engineer 9/24/2025 Rhimou Sulldi, RSULLDI Engineering 9/25/2025 All All changes made in Revision 5 Supervisor Role Definitions:

P/R/A designates Preparer (P), Reviewer (R), Approver (A);

LP/LR designates Lead Preparer (LP), Lead Reviewer (LR):

M designates Mentor (M)

PM designates Project Manager (PM)

Controlled Document 0402-01-F01 (Rev. 023, framatome 1 Rev,

023, Document No. 32-9393028-003 Callaway BMI Nozzle One-Cycle Justification Section III Analysis Professional Engineer Certification l, the undersigned, being a Certifying Engineer competent in the applicable field of design and using the Design Specification and the drawings identified in the references as a basis for design, do hereby certify that to the best of my knowledge and belief the statements made and the conclusions drawn are correct and applicable to the affected in-scope items.

Printed Name:

ITT Harrison Il Date:

Sept 23, 2025

Title:

Consulting Engineer Signature:

Seal:

'S HT HARRISON

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section II] Analysis Record of Revision Revision Pages/Sections/Paragraphsl Brief Description

/ Change Authorization Number Changed Initial Release. The content of this document is identical to 32-9392552-000, except that proprietary information is

_ tedacted.

The content of this revision is identical to 32-9392552-002, except that proprietary information is redacted and the Record of Revision is eliminated. See Record of Revision in

_ 32-9392552-002 for changes.

a The content of this revision is identical to 32-9392552-004, except that proprietary information is redacted and the Record of Revision is eliminated. See Record of Revision in

_ 32-9392552-004 forchanges.

Removed proprietary brackets associated with the 18-month

_ cycle of operation.

Section 2 and Section 7

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI NozzleOne-Cycle Justification Section Ill Analysis Table of Contents Professional Engineer Certification Record of Revision List of Acronyms 1

Introduction 1.1 Purpose and Scop

1.2 Background

1.3.

Results Analytical Methodology Assumptions 3.1 Unverified Assumptions 3.2 Verified Assumptions Design Inputs 4.1 Computer Usage 5.1 Calculations 6.1 Primary Stress Evaluation 6.1.1 ASME Code Allowable Stresses.

6.1.2 Loading 6.1.3 Primary Stress Intensity and Pure Shear Stress...

6.1.4 Triaxial Stress Qualification Weld Size Requirements 6.2.1.

J-Groove Weld Preparation Modification Tentative Thickness Calculation Reinforcement Requirements 6.4.1 Removed Area 6.4.2 Limits of Reinforcement 7.1.

BMI Nozzles #30, #35, and #57 References A1

[

Controlled Document Document No. 32-9393028-003 framatome

.Callaway.BMI Nozzle One-Cycle Justification Section III Analysis A2 [

A.3 Loading Comparison A.4 Pressure Design A5 [

] Weld Sizing A.6 Conclusion A.7 Long Fitting with One-Side Coupling Fitting Guide Tube Replacement Contingency for BMI Nozzles

1. 30, #35, #48 and #57 BMI Nozzle #57 Reinforcement B.1 Removed Area B.2 Limits of Reinforcement B.3 Available Reinforcement Area

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle JustificationSection II] Analysis List of Figure Figure 4-1: Half-Nozzile Repair Drawing Figure 6-1: Location Analyzed Figure 6-2: Location of External Loads Figure 6-3: [

Figure 6-4:

Figure 6-5: [

Figure 6-6: [

Figure 6-7: Reinforcement Area Dimensions Figure 6-7: Original J-groove Weld Uphill Area Figure 6-8: Original J-groove Weld Downhill Area Figure 6-9: Added Area of Reinforcement Uphill Figure 6-10: Added Area of Reinforcement Downhill Figure A-1: Fillet and Socket Weld Dimension Requirements Figure A-2: Socket Weld Repair Drawing Figure A-3: Contingency Thimble Guide Tube Fitting Figure B-1: Original J-groove Weld Uphill Area for BM! Nozzle #57 Figure B-2: Original J-groove Weld Downhill Area for BMI Nozzle #57 Figure B-3: Added Area of Reinforcement Uphill BMI Nozzle #57 Figure B-4: Added Area of Reinforcement Downhill BMI Nozzle #57

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section II! Analysis List of Tables Table 4-1: BMI Nozzle Repair Dimensions Table 4-2: Material Designations Table 4-3: Material Stress Limits Table 6-1: Alloy 690 Primary Stress Limits Table 6-2: External Load Summary Table 6-3: Internal Pressure Summary Table 6-4: Local Piping Loads Under Service Levels Table 6-5: Primary Stress Qualification Table 6-6: Pure Shear Stress Qualification Table 6-7: Triaxial Stress Qualification Table 6-8: Weld Size Requirement Results Table A-1:

[

Table A-2:

[

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis List of Acronyms Acronym Definition BMI Nozzle Bottom Mounted Instrument Nozzle Css Calculation Cover Sheet from Framatome Procedure 0402-01-F01 LOCA Loss of Coolant Accident OBE Operating Basis Earthquake OCJ One-Cycle Justification SRSS Square Root of the Sum of the Squares SSE Safe Shutdown Earthquake

Controlled Document Document No. 32-9393028-003 framatome

_ _Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis 1

Introduction 1.1.

Purpose and Scope The purpose of this calculation is to qualify the Callaway No. 48 Reactor Vessel Bottom Mounted Instrument (BMI)

Nozzle half-nozzle repair for one cycle of operation according to the ASME B&PV Code Section IIl requirements (Ref. [1]).

Unacceptable indications were also found on the Callaway BMI Nozzles #30, #35, and #57 and are to be repaired using nearly the same method and the same materials as BMI Nozzle #48. A subsequent analysis will demonstrate the acceptability of the repaired penetrations for operation beyond one cycle. The socket welds connecting the thimble guide tubes to the replacement nozzles and the couplings are addressed in Appendix A.

1.2 Background

During the Spring 2025 outage, a leak in the Callaway No. 48 BMI Nozzle was discovered. A half-nozzle repair is being performed per (Ref. [2]). In addition, unacceptable indications on BMI Nozzles #30, #35, and #57 were also discovered.

The repair process for BMI Nozzle #48 is as follows. After cutting and removing a section of the BMI Nozzle guide tube, the half-nozzie repair process requires deposition of an Inconel Alloy 52M weld pad using a machine gas tungsten arc welding (GTAW) process and ambient Temperbead technique. After acceptable NDE of the weld deposit, the lower nozzle section will be bored and removed to a point within the reactor vessel (RV) lower head. The weld pad will be counter bored to a slightly larger diameter than the base outside diameter (OD) of the replacement nozzle. This will enable a half nozzle replacement which moves the new structural weld boundary to the vessel OD yet leaves the existing structural weld intact without over constraining the existing Alloy 600 nozzle. The new half nozzle will be inserted into the bore and welded to the Inconel Alloy 52M weld deposit and then reattached to a replacement BMI Nozzle guide tube using a coupling that is socket welded to the thimble guide tube.

The only repair method difference between BMI Nozzle #48 and BMI Nozzles #30, #35, and #57 is that the repair method for BMI Nozzles #30, #35, and #57 do not include steps for roll expansion and boring the nozzle (Ref. [15)).

This difference does not impact this analysis.

Ref. [15] is updated to revise the J-weld preparation on the downhill side for nozzles #30, #35, and #57 and the weld pad for nozzle #57. A review of the subsequent qualification concluded that the pure shear calculation and the area of reinforcement are affected due to potential removal of unacceptable indications through grinding, up to a depth of [

]

and extending circumferentially up to [

]

Conservatively, note 13 is considered in the analysis of Nozzle #48. Note that, per [

] an unacceptable indication was identified in the bore of BMI Nozzle #48 and was cleared by localized grinding to a depth of [

] This is in accordance with Note 14 of the repair drawing Ref. [4] and does not constitute a deviation from the design.

1.3.

Results The calculation herein demonstrates the half-nozzle repair for BMI Nozzle #48 satisfies the applicable requirements of the ASME B&PV Code (Ref. [1]) for one cycie of operation. Section 7.1 and Appendix B demonstrate that the half-nozzle repairs for BMI Nozzles #30, #35, and #57 satisfy the applicable requirements of the ASME B&PV Code (Ref. [1]) for one cycle of operation.

Controlled Document Document No. 32-9393028-003 framatome

_ Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis 2

Analytical Methodology

¢ Compliant with the ASME B&PV Code (Ref. [1]) the following steps will be performed to demonstrate the acceptability of the half-nozzle repair:

• Primary stress criteria will be evaluated at the new J-groove weld and existing BM! Nozzle.

• Reinforcement requirements will be evaluated.

Acceptability of the new J-groove weid configuration with respect to the ASME Code dimensional requirements will be determined.

A qualitative assessment of the primary + secondary stress (P+Q) as well as fatigue will be made regarding a single cycle of operation (18 months).

3 Assumptions 3.1 Unverified Assumptions There are no unverified assumptions used in this calculation.

3.2 Verified Assumptions

. The stress limits and materials properties for Inconel Alloy 52M are taken to be the same as

[

] as the chemical compositions of these metals align closely.

. The arc length distance to the nearest nozzle in the area of reinforcement calculation is approximated as the chord distance between where the penetration centerlines intersect the sphere made by the mean radius of the reactor vessel. This approximation is acceptable because the included arc angle is less than 7°, making the arc length effectively equal to the straight-line chord distance.

. Note 13 of Ref. [15] does not indicate the height of the grinding along the bore. It is conservatively assumed that the height is. [

] (Action #4 of [19]).

. Other minor justified assumptions are stated throughout the calculation as used.

4 Design Inputs 4.1 Geometry Important nominal dimensions for the repair are listed in Table 41. The repair is shown in Figure 41.

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification SectionIllAnalysis Table 4-1: BMI Nozzle Repair Dimensions Page 12

Document No. 32-9393028-003 Figure 4-1: Half-Nozzle Repair Drawing Q

Pr oO ec

=

2 a

ol oO 9p) 2 pd:

oO oO

=

ond

=)

2 oO 9

oO c

QO a)

N N

[oy z

=l

=

co

=~

4]

=

AS) o oO framatome

Controlled Document Document No. 32-9393028-003 framatome

_Callaway BMI Nozzle One-Cycle Justification Section II Analysis 4.2 Materials The material designations for the sub components are listed in Table 42. [

properties for the J-groove weld are taken to be the same as SB-166 (alloy 690) as the chemical compositions of J

Table 4-2: Material Designations Table 4-3 lists the material properties for the materials used in the analysis at the [

]

(Ref.[6]).

[

]

material specifications come from Ref. [7]. All other Sm values come from the original construction code for the reactor vessel and bottom instrumentation tubing, Ref. [8], and Sy and Su values come from Ref. [9].

Table 4-3: Material Stress Limits 5

Computer Usage 5.1 Software The software is being used within its specified range of applicability as defined by validation and verification requirements defined in Ref. [10]. All software errors notices applicable to this software have been reviewed and found to have no effect on this document.

Page 14

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis 5.2 Computer Files The computer files used in the analysis can be found in the

[

]

The listing of archived computer files is as follows:

L 6

Calculations Note that all dimensions in the following sections will use the worst-case dimension, accounting for tolerances stated on the design drawings, unless otherwise stated. If no tolerance is listed the nominal value is used.

In addition, similar analyses of half-nozzle repairs performed for other plants have successfully met all ASME Section lil criteria in the required follow-on analysis for the life of repair.

Page 15

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section Il Analysis 6.1 Primary Stress Evaluation Per Ref. [2], a primary stress intensity evaluation is required using the criteria defined in Ref. [1]. The evaluation checks stresses on the J-groove weid and the BMI Nozzle due to internal pressure and external loads. Stresses at each service level are evaluated. Figure 6-1 describes the locations analyzed.

A Outside Mean Inside J

YYyyly VAJ G WYK Figure 6-1: Location Analyzed

Controlled Document Document No. 32-9393028-003 framatome

_Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis 6.1.1 ASME Code Allowable Stresses Allowable stresses are calculated at the [

] (Ref. [6]) using the limits in Ref. [1].

allowable stresses for each service level are listed in Table 6-1.

Table 6-1: Alloy 690 Primary Stress Limits Normal operating condition stresses are not considered as there are no specific limits defined per NB-3222.1, Ref. [1]. The allowable stresses for Upset (Level B) Conditions are per NB-3223, Ref. [1], respectively. The allowable stresses for emergency (Level C) Conditions are per NB-3224, Ref. [1]. The allowable stresses for Faulted (Level D)

Conditions are per NB-3225 Ref. [1]. Testing limits are per NB-3226 Ref. [1]. The allowable stresses for pure shear are per NB 3227.2, Ref. [1].

6.1.2 Loading

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis Figure 6-2: Location of External Loads Page 18

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis Table 6-2: External Load Summary l

~ Page 19

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis.

The maximum internal pressure for each service level are taken from the transients defined in Ref. [3] and are listed in Table 6-3.

Table 6-3: Internal Pressure Summary The load combinations are specified in Ref. [3]. For primary stress evaluation, the load combinations are listed as follows: _

Table 64 calculates the services loads based on the loading combinations. Seismic loads act in the positive and negative directions, but the magnitude is taken to generate the highest stress intensity. Conservatively, deadweight is considered to act in the same direction as pressure and seismic loads.

Table 6-4: Local Piping Loads Under Service Levels 6.1.3 Primary Stress Intensity and Pure Shear Stress

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section II Analysis Below are the general equations used to calculate the stresses:

The equations used to calculate the stress components are as follows:

The section properties of the nozzle are calculated as:

Unknowns:

• Anoz, in, area of the nozzle

• kx, in, area moment of inertia of the nozzle

<< Mb, in-kip, bending moment on the nozzie

• Fs, kip, shear force on the nozzie Gaxiai,m, ksi, axial membrane stress

Controlled Document Document No. 32-9393028-003 framatome

____ Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis.

Oaxiai,B, KSi, axial bending stress Oaxial,mB, Ksi, axial membrane + bending stress Ghoop, ksi, hoop stress Oradial, ksi, radial stress Ixy, ksi, shear stress r

Sy a t S,

Syz xy Sty

§,

Sxz Q

S, Knowns:

• Ro, in, 1/2 of Replacement BMI Nozzle OD (Table 41)

• Ri, in, 1/2 of Replacement BMI Nozzle ID (Table 4-1)

• R, in, inner, mean, or outer radius of BMN (mean is calculated)

• Larm, 8.9 in, Nozzle Moment Arm (Table 41)

• Fy, Fy, Fz, kip, External Forces on BMI Nozzle (Table 6-4)

• Mx, My, Mz, in-kip, External Moments on BMI Nozzle (Table 6-4)

• P, ksi, pressure at service level (Table 6-3)

Principal stress is calculated as the eigenvalue of each eigenvector xi, {i]i < 3, i N} of the stress tensor, as follows.

where each stress term is defined below:

• Sic

• Oaxial,M OF Ogxial, MB bd Sy

= Ohoop

• Sz = Orad

• Sxy = ty

• Syz

= 0

• Skz = 0 The stress intensity is then the maximum difference between principal stress terms, as follows:

Sint

= max (lS

- Sf, (S -S], 1S -S])

The primary stress qualifications are summarized in Table 6-5.

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section IIl Analysis Table 6-5: Primary Stress Qualification

_l Unknowns:

¢ throat, iN, Minimum thickness of the j-groove weld throat Avweu, in, shear area of the weld

¢ Feap, kip, force due to cap pressure on weld Tweia, KSi, Shear stress Knowns:

Cy1, in, fillet leg length (Table 4-1)

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis C,2, in, depth of j-groove weld (Table 4-1)

Ro, in, 1/2 of Replacement BMI Nozzie OD (Table 41)

Fy, kip, External Axial Force on BMI Nozzle (Table 64)

P,ksi, pressure at service level (Table 6-3)

The pure shear stress qualifications are summarized in Table 6-6.

Table 6-6: Pure Shear Stress Qualification 6.1.4 Triaxial Stress Qualification NB-3227.4 of Ref. [1] requires the algebraic sum of the three primary principal stresses (0; + 02 + 03) for Level A or Level B service limits shall not exceed:

For Level C service requirements, the algebraic sum of the three primary principal stresses (co; + o2 + 03) shall not exceed:

Note: The triaxial stresses are calculated using the membrane + bending principal stresses as these values bound the membrane stresses. Design, Faulted, and Test service levels are also conservatively considered. Limitas is used for the Design service level, while Limitc is used for the Faulted and Test service levels. The triaxial stress qualifications are summarized in Table 6-7.

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis Table 6-7: Triaxial Stress Qualification 6.2 Weld Size Requirements The j-groove weld needs to satisfy the minimum dimension requirements of Figure NB-4244 [

] per Ref. [1].

Fig. NB-4244 [

]

is shown in Figure 6-3. The nominal thickness of the BMI Nozzle is calculated as:

d,

_ L.6880inch 0.61507nch

a 2

= 0.5365inch Hweta = Cr + Lgroove

= 9.4400 + 0.4400

= 0.8800 Where:

tn, in, nominal thickness of the nozzle (Table 41)

• do, in, Replacement Nozzie OD (nom) (Table 41)

• di, in, Replacement Nozzle ID (Table 41)

Hweia, in, Minimum weld height (Table 41)

Cx, in, Replacement Fillet Weld Leg Length (min) (Table 4-1)

• Lgroove, in, Replacement J-groove Depth (min) (Table 4-1)

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis Figure 6-3: [

Page 26

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle Qne-Cycle Justification Section III Analysis Figure 6-4: Weld Repair Drawing Dimensions Page 27

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI NozzleOne-Cycle Justification Section Ill Analysis Figure 6-5:

[

Table 6-8: Weld Size Requirement Results Page 28

Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification SectionIllAnalysis 6.2.1 J-Groove Weld Preparation Modification The J-Groove weld preparation modification is designed for nozzles #30, #35 and #57 to mitigate possible weldability issues. The only difference between nozzle #48 and the above-mentioned nozzles is a shallower cut on the downhill side as depicted on Figure 6-4 per Ref. [15]. Figure 6-6 depicts the difference of the J-weld configuration between nozzle #48 and nozzles #30, #35 and #57. The weld size for nozzles #30, #35 and #57 is maintained the same as that of for nozzle #48. Therefore, as it can be observed, the weld filler on the downhill side, which fills the shallower cut of the weld preparation, occupies a larger volume, and the fillet portion extends higher than that of nozzle #48.

It is concluded that performing the modification of the J-weld preparation only on the downhill side has no impact on the minimum weld size code qualification, area of reinforcements and primary stresses. Primary plus secondary stresses are negligibly impacted for the consideration of one operating cycle.

HYPSs aA l Y\Y YAY YY AY YY y'Y ZY YY 1

A:

AY YiY A\Y leg x

Ss, UMMM 4

L Lididegitid/

li hike

_I 1

DWas VELELELED VLE L LN Vi bbdddieided Figure 6-6: [

Controlled Document Document No. 32-9393028-003 framatome

.. Callaway BMINozzle One-Cycle Justification Section II Analysis 6.3 Tentative Thickness Calculation The tentative thickness calculation of the RV and nozzie are determined by the methodology specified in NB-3324 of the ASME boiler and Pressure Vessel Code (Ref. [1]). As stated in the article, except in local areas, the wall thickness of a vessel shall never be less than that obtained from the formula in NB-3324.1 for cylindrical shells and NB-3324.2 for spherical shelis.

Where:

• thozzie, in, Tentative thickness of BMI Nozzle

• tev, in, Tentative thickness of Reactor Vessel

• P, psi Design pressure

• Rinozzie, in, BMI Nozzle Inner Radius SmMnozzie, in, Alloy 690 design stress intensity value

• Rirv, in, RV Inner Radius

• Smryv, psi, SA-533 Gr. B Ci. 1 design stress intensity value The nozzle wall thickness considering the nominal dimensions is:

thoz = ROnoz Rinoz

[

The reactor vessel wall thickness considering the nominal dimensions is:

tev

= [

]

The nominal wall thickness is greater than the tentative thickness for both the BMI Nozzle and the RV, therefore the requirements are met.

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section II] Analysis 6.4 Reinforcement Requirements Due to the area removal in the RV to accommodate the BMI! Nozzle, an evaluation is required to determine the reinforcement requirements are met. The calculation for the minimum required area of reinforcement is based on the methodology listed in NB-3330 Ref. [1]. Figure 6-6 describes the dimensions and areas being analyzed.

Figure 6-7: Reinforcement Area Dimensions

Controlled Document Document No. 32-9393028-003 framatome

_ Callaway BMI Nozzle One-Cycle Justification Section III Analysis 6.4.1.

Removed Area

Controlled Document framatome Document No. 32-9393028-003

__ Callaway BMI Nozzle One-Cycle Justification Section III Analysis 6.4.2 Limits of Reinforcement Ref.

[1] establishes the limits of the reinforcement area along and normal to the vessel surface.

The limits of reinforcement, measured along the mid surface of the nominal wail thickness, shall meet the following:

1. One hundred percent of the required reinforcement shall be within a distance on each side of the axis of the opening equal to the greater of the following: NB-3334.1(a)(1), [

]

a=[

l NB-3334.1(a)(2), Sum of radius of finished opening, thickness of nozzle tnoz (conservatively equal to zero) and vessel wall tw which equals:

2.

In addition, two thirds of the required reinforcement shall be within a distance on each side of the axis of the opening equal to the greater of the following: NB-3334.1(b)(1):

Where:

<< Ris the mean radius of head

• tis the nominal vessel wall thickness

• ris the radius of the finished opening in the corroded condition:

NB-3334. 1(b)(2):

Where:

• ris the radius of the finished opening in the corroded condition tn is the nozzle thickness ( [

})

• tis the nominal vessel wall thickness

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis Accordingly, the limit of reinforcement L, is:

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis 6.4.3 Available Reinforcement Area The available area of reinforcement is shown in Figure 6-6 and is calculated as follows: The outside radius of the RV (Ro) is:

R=Rit+t=[

]

The vertical distance from center of head to outside radius of the RV (H.) is:

The thickness of the RV (¢,) that was not removed is:

wl The area of the original flawed J-groove weld needs to be account for as area removed. Figure 67 and Figure 6-8 show the nominal areas of the original j-groove weld and buttering.

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section Ili Analysis_

Figure 6-8: Original J-groove Weld Uphill Area

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis Figure 6-9: Original J-groove Weld Downhill Area

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis Figure 6-10: Added Area of Reinforcement Uphill Page38

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section IIIAnalysis Figure 6-11: Added Area of Reinforcement Downhill Page 39

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis The total area of reinforcement is:

The required area of reinforcement specified in NB-3332.2 is (Correction factor F=1.0 for spherical vessels):

The remaining reinforcement area is:

The total reinforced area meets the required area of reinforcement Areg, and is greater than the total area removed, therefore the reinforcement requirements are met.

However, NB-3331(c) states that the provisions of NB-3331(a) and (b) above are not intended to restrict the design to any specified section thicknesses or other design details, provided the basic stress limits are satisfied. If it is shown by analysis that all the stress requirements have been met, the rules of NB-3330 are waived (Ref. [1]).

The diametrical clearance referenced here is between the replacement nozzle and the bore of the penetration on the RV lower head. While the external loads are applied at the end of the nozzle, these loads are resisted by the new J-Groove weld and are not transmitted through the weld into the nozzle inside the penetration to interact with bore. As a result, this clearance does not significantly affect the stresses produced by the external loads.

6.5 Primary Plus Secondary Stress and Fatigue Usage Criteria The ASME Code placesa limit on the primary plus secondary stress intensity in order to prevent failure by excessive distortion and ratcheting caused by the repeated application of loads. The Code also limits total stress, through the cumulative fatigue usage factor, in order to prevent failure by fatigue. Primary plus secondary stress intensity and fatigue for one cycle are qualitatively assessed in the following paragraph. The 35m primary plus secondary stress check will be performed as part of the required subsequent full Section III analysis for the remaining service life.

Page 40

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis Based on this precedent and the current analysis, the new half-nozzle repair is considered acceptable for one operating cycle.

7 Results The calculation herein demonstrates the half-nozzle repair for BMI Nozzle No. 48 satisfies the applicable requirements of theASME B&PV Code (Ref. [1]) for one cycle of operation. The primary stress criteria are met for the new J-groove weld and existing BMI Nozzle. The tentative thickness, reinforcement requirements, and weld repair size were all demonstrated to be compliant with the Code. A qualitative assessment of the primary + secondary stress (P+Q) as well as fatigue was made justifying a single cycle of operation (18 months).

7.1.

BMI Nozzles #30, #35, and #57 Primary Stress Assessment:

All BMI Nozzies have the same original drawing and same original thimble drawing (Ref. [14]); thus, all BMI Nozzles have the same original materials. All BMI Nozzles have external loads applied at the bottom of their respective penetration tubes based on the original drawing (Ref. [3]), and internal pressure is consistent across all penetrations. As indicated by the original drawing (Ref. [14]), the nominal bending arms for all penetrations are at their respective centerlines.

This OCJ analysis of BMI Nozzle #48 conservatively uses the long tube external loads and the transients defined pertain to all BMI Nozzles. Therefore, the resulting primary stresses will be conservatively the same for all BMI Nozzles.

Weld Size Assessment:

The weld size requirements for nozzle #48 were analyzed in Section 6.2 and found to meet the applicable criteria. The key dimensions relevant to the weld size assessment are identical for BMI nozzles #48, #30, #35 and #57 (Ref. [4], [5], [15],

and [16],). As stated in Section 1.2, the only repair method difference between BMI Nozzle #48 and BMI Nozzles #30,

1. 35, and #57 is that the repair method for BMI Nozzles #30, #35, and #57 do not include steps for roll expansion and boring the nozzle (Ref. [15]). This difference does not impact this analysis.

Therefore, it is concluded that nozzles #30, #35, and #57 are bound by the weld size requirements of BMI Nozzle #48 and meet the applicable criteria.

Reinforcement Assessment:

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis 7

Therefore, the OCJ analysis of BMI Nozzle #48 for reinforcement requirements, as presented in Section 6.4, bounds BMI Nozzles #30 and #35. The reinforcement requirements for BMI Nozzle #57 are analyzed in Appendix B.

Primary Plus Secondary Stress, and Fatigue Assessment:

BMI Nozzle #48 is located further from the centerline of the RV lower head than that of BMI Nozzles #30 and #35 and will experience higher primary and secondary stresses for the same pressure conditions and external/thermal loading. BMI Nozzle #30 and #35 are thus bound by BMI Nozzle #48.

As discussed in Section 6.5, BMI nozzle #48 has been qualitatively justified for primary plus secondary stress and fatigue usage criteria for one operating cycle. The same qualitative justification can be made for BMI nozzles #30, #35, and #57, and a quantitative analysis of the 3Sm primary plus secondary stress check will be performed as part of the required subsequent full Section III analysis.

Repairing Multiple BMI Nozzles:

The previous analyses performed by Framatome referred to in Section 6.5 consisted of a symmetric 3D finite element model of the repair weld and replacement nozzle on the reactor head, along with adjacent nozzle bores. By applying a symmetric boundary condition, these analyses conservatively evaluate multiple nozzle repairs on the same reactor head.

Therefore, it is considered acceptable for BMI Nozzles #30, #35, and #57 to be repaired along with BMI Nozzle #48 for one operating cycle and will be quantitatively assessed in the full Section IIi analysis.

Thimble Guide Tube to Replacement Nozzle and Coupling Analysis:

As discussed in Appendix A, the original stress analysis on the weld bounds the repair design welds for BMI Nozzie #48.

All BMI Nozzies have the same original nozzle and TGT drawings, and BMI Nozzles #30 and #35 will be repaired using the same design and materials as BMI Nozzle #48.

Therefore, the original stress analysis on the weld bounds the repair design welds for BMI Nozzles #30, #35, and #57.

Conclusion for BMI Nozzle #30, #35, and #57:

Based on the analysis presented in this section and Appendix B, it is considered acceptable for BMI Nozzles #30, #35, and #57 to be repaired along with BMI Nozzle #48 for one operating cycle and will be quantitatively assessed in the full Section III analysis.

framatome Controlled Document Document No. 32-9393028-003

_Callaway BMI Nozzle One-Cycle Justification Section lil Analysis.

8 References

[1]

ASME Boiler and Pressure Vessel Code. Section Ill, "Rules for Construction of Nuclear Facility Components, Division 1", 2015 Edition.

Framatome Document [

Framatome Document

[

Framatome Drawina [

Framatome Drawing [

Framatome Document [

l ASME Boiler and Pressure Vessel Code, Section Il, Part D, "Materials", 2015 Edition.

ASME Boiler and Pressure Vessel Code, Section Ill, "Rules for Construction of Nuclear Power Plant Components", 1971 Edition with addenda through Winter 1972.

ASME Boiler and Pressure Vessel Code, Section Il, "Material Specifications". 1971 Edition with addenda through Winter 1972.

Framatome Software Release Authorization [

]

Framatome Document [

Framatome Drawing [

Framatome Drawing [

Framatome Document [

]

Framatome Drawing [

Framatome Drawing [

]

NRC Relief Request ML14149A403. Relief Request 52 Proposed Alternative in Accordance with 10 CFR 50.55(a)(3)(i). Attachment 4. ASME Section Ill End of Life Analysis of PVNGS3 RV BMI Nozzle Repair.

Framatome Drawing [

[

Controlled Document framatome Document No. 32-9393028-003 Callaway BMI Nozzle One-Cycle Justification Section III Analysis.

Where:

e

=$Cxtoia, in, Short weld leg on original [

= Cx2oia, in, Long weld leg on original [

e dz, in, Outer diameter of original BMI nozzle [

]

e di, in, Inner diameter of original BMI nozzle [

]

The outer diameter of the original [

]

is taken as the inner diameter of the original nozzle.

Dimensions for the

[

]

are taken from Ref. [12]. All other dimensions are taken from Ref. [4]. The dimensions of the l

]

welds are [

]

inches. The new weld exceeds the size of the old weld, resulting in lower primary stresses than the original calculation. The [

]

was not included in the original design, however the section properties of the [

J and the original [

J are compared in Table A-1.

Table A-1: [

]

Controlled Document Document No. 32-9393028-003 framatome

_ Callaway BMI Nozzle Qne-Cycle Justification Section III Analysis Where:

• By, Stress index for pressure loading

• Spress, pSi, Pressure stress intensity calculation Reg, design stress intensity requirement Ratio, Ratio of pressure stress intensity to the design stress intensity requirement teoupting, in, Nominal thickness of the [

]

Cx new, in, Short weld leg on the [

P, psia, Design pressure docoupting, in, Outer diameter of the [

Sm, psi, Allowable stress intensity of [

Page 45

Controlled Document Document No. 32-9393028-003 framatome Callaway BM! Nozzle One-Cycle Justification Section Ill Analysis Table A-2: [

A.3_

Loading Comparison A.4 Pressure Design To meet the requirements of NB-3641.1, the [

] must have a minimum thickness of:

Where:

tm, in, Minimum thickness of [

• P, psi, Design Pressure

• d,in, [

] op

• Sm, psi, Allowable stress of [

+ A, in, Additional Thickness The thickness of the thimble guide tube is larger than the minimum thickness, therefore the requirement is met.

A5

[

] Weld Sizing The new welds must meet the requirements of Fig. NB-4427-1, shown in Figure A-1.

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section Iii Analysis Figure A-1: Fillet and Socket Weld Dimension Requirements

Controlled Document Document No. 32-9393028-003 framatome

__. Callaway BMI NozzleOne-Cycle Justification Section I! Analysis Figure A-2: Socket Weld Repair Drawing A.6 Conclusion A.7 Long Fitting with One-Side Coupling Fitting Guide Tube Replacement Contingency for BMI Nozzles #30, #35, #48 and #57 l

l Page 48

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis Figure A-3: Contingency Thimble Guide Tube Fitting Page 49

7 Controlled Document framatome Document No. 32-9393028-003 Callaway BMI Nozzle One-Cycle Justification Section III Analysis_

B BMI Nozzle #57 Reinforcement B.1 Removed Area The vertical distance from center of head-to-head inside radius (Hi) for BMI Nozzle #57 is:

The vertical distance from center of head to the outside radius of the required head thickness (H;) for BMI Nozzle #57 is:

Removed area due to opening (Arem) for BMI Nozzle #57 is:

B.2 Limits of Reinforcement Recall from Section 6.4.2 that the limits of reinforcement, measured along the mid surface of the nominal wail thickness, shall meet the following:

1. One hundred percent of the required reinforcement shall be within a distance on each side of the axis of the opening equal to the greater of the following: NB-3334.

1(a)(1), [

]

Controlled Document framatome Document No. 32-9393028-003 Callaway BMI Nozzle One-Cycle Justification Section III Analysis NB-3334.1(a)(2), Sum of radius of finished opening, thickness of nozzle tnoz (conservatively equal to zero) and vessel wall tw which equals:

2.

In addition, two thirds of the required reinforcement shall be within a distance on each side of the axis of the opening equal to the greater of the following: NB-3334.1(b)(1):

[

Where:

<< Ris the mean radius of head

• tis the nominal vessel wall thickness

• ris the radius of the finished opening in the corroded condition:

NB-3334. 1(b)(2):

Where:

• ris the radius of the finished opening in the corroded condition

• t, is the nozzle thickness (conservatively equal to zero)

• tis the nominal vessel wall thickness

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle Qne-Cycle Justification Section Ill Analysis

= _

B.3 Available Reinforcement Area The thickness of the RV (t,) that was not removed is:

The area of the original flawed J-groove weld needs to be account for as area removed. Figure B-1 and Figure B-2 show the nominal areas of the original j-groove weld and buitering.

Page 52

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section II Analysis.

Figure B-1: Original J-groove Weld Uphill Area for BMI Nozzle #57

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification SectionllAnalysis...

Figure B-2: Original J-groove Weld Downhill Area for BMI Nozzle #57 The nominal areas of the added material from the weld pad and j-groove weld on the uphill and downhill sides are shown in Figure B-3 and Figure B-4.

Page 54

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section III Analysis.

Figure B-3: Added Area of Reinforcement Uphill BMI Nozzle #57 Page 55

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification Section Ill Analysis Figure B-4: Added Area of Reinforcement Downhill BMI Nozzle #57 Page 56

Controlled Document Document No. 32-9393028-003 framatome Callaway BMI Nozzle One-Cycle Justification SectionIllAnalysis The total reinforced area meets the required area of reinforcement Areg, and is greater than the total area removed, therefore the reinforcement requirements are met.

Page 57

Controlled Document framatome 20004-028 (03/26/2024)

Framatome Inc.

Engineering Information Record Document No.:

51 9392748 003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs Page 1 of 31

Controlled Document 20004-028 (03/26/2024) framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs Safety Related?

YES [l NO Does this document establish design or technical requirements?

[ ] YES NO Does this document contain assumptions requiring verification?

[l YES NO Does this document contain Customer Required Format?

[ l YES NO Signature Block Name and Title Signature and Date Role Scope/Comments Stacy Yoder jSL YODER Engineer IV 9/25/2025

~~"

"CA WICKER John Neil for CJ NEIL Engineer IV 9/25/2025

- Craig Wicker ICA WICKER Supervisory Engineer 925/2025 Ed Moreno EM MORENO

)

Approval of customer references

. Project Manager 9/26/2025 I.

Role Definitions:

P/R/A designates Preparer (P), Reviewer (R), Approver (A);

LP/LR designates Lead Preparer (LP), Lead Reviewer (LR);

M designates Mentor (M);

PM designates Project Manager (PM)

Controlled Document 20004-028 (03/26/2024) framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs Record of Revision l Revision [

Pages/Sections/

]

No.

Paragraphs Changed Brieff Description / Change Authorization 000 All Original release. The proprietary version of this documentiis51-9392522-001.

l 001

' The content of this revision is identical to 51-9392522-002, except that proprietary information is redacted and the Record of Revision is eliminated. See Record ofRevisionin 51-9392522-002 for changes.

The content ofthis revision is identical to 51-9392522-003, except that proprietary informationis redacted and the Record of Revisionis eliminated. See

_ Record of Revisionin 51-9392522-003 for changes._

The content of this revision is identical to 51-9392522-004, except that proprietary informationis redacted and the Record of Revisionis eliminated. See Record of Revision in 51-9392522-004 for changes.

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs Table of Contents SIGNATURE BLOCK RECORD OF REVISION LIST OF TABLES LIST OF FIGURES 1.0 2.0 ASSUMPTIONS 2.1 Justified Assumptions....

2.2 Assumptions Requiring Verification INDUSTRY OCCURRENCES OF EXPOSED CARBON/LOW ALLOY STEEL BASE CORROSION OF LOW ALLOY STEEL EXPOSED TO RCS 41 Methodology 4.2 General Corrosion 4.2.1 General Corrosion Data 4.2.2 Pressure Boundary Leakage (Wastage) 4.2.3 Long Term General Corrosion 4.3 Crevice Corrosion 4.4 4.5 Stress Corrosion Cracking 46 Hydrogen Embrittlement 4.7

[

CORROSION OF ALLOY 690 AND ALLOY 52M 5.1 General Corrosion 5.2 5.3 5.4 Low Temperature Crack Propagation 5.5 Stress Corrosion Cracking SCC SUSCEPTIBILITY OF STAINLESS STEEL THIMBLE GUIDE TUBE ADJACENT TO THE ALLOY 52M SOCKET WELD SCC SUSCEPTIBILITY OF STAINLESS STEEL COMPONENTS NEAR THE COUPLING CONCLUSIONS REFERENCES

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs List of Tables Table 4-1:

[

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vesse! Bottom Mounted Instrument Nozzle Repairs List of Figures Figure 1-1:

Original Callaway BMI Nozzle Penetration Configuration [Adapted from 2, 3, 4]

Figure 1-2:

Repaired Callaway BMI Nozzle Penetration #48 Primary Configuration [1, 5]

Figure 1-3:

[

Figure 1-4:

Repaired Callaway BMI Nozzle Penetrations #30, #35, and # 57 Configuration [1, Adapted from 2, 3, 4]

Figure 1-5:

[

Controlled Document framatome l

Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs

1.0 BACKGROUND

/PURPOSE During the 2025 (R27) Mode3 startup leak check visual inspection at Callaway, potential reactor coolant leakage was identified. The leakage was observed at Bottom Mounted Instrumentation (BMI) nozzle, Penetration #48, on the outside surface of the reactor vessel bottom head (RVBH) at the interface between the RVBH penetration and the BMI nozzle [1]. As part of the subsequent extent-of-condition investigation, ultrasonic testing and visual examinations were performed on all 58 BMI nozzles. Fabrication flaws were discovered in the BMI nozzle 48 J-groove weld, and unacceptable indications consistent with stress corrosion cracking (SCC) were found on the J-groove welds of BMI nozzles #30, #35, and #57.

The original BMI nozzle #48 configuration, as shown in Figure 1-1 [2, 3, 4] consists of an Alloy 600 nozzle welded to the RVBH inside surface with Alloy 182 weld material [1]. Figure 1-1 is representative of the general original configuration for BMI nozzles #30, #35, and #57.

It is noted that Figure 1-1 has been edited herein from Reference [2] to exclude the temporary mechanical plug and dimensions from the figure.

Framatome will utilize the half-nozzle approach to repair the BMI nozzle configuration at the penetrations #30,

1. 35, #48, and #57 locations. Figure 1-2 [5, 6] and Figure 1-4 [2, 3, 4] provide the primary repaired configurations for nozzles #48 and #30, #35, and #57, respectively. For each nozzle, there is a contingency option modifying the method for attachment ofthe existing thimble guide tube to the new half-nozzle. Figure 1-3 [5, 6] and Figure 1-5

[2, 3, 4] provide the contingency repaired configurations for nozzles #48 and #30, #35, and #57, respectively.

Hereafter mention of the repaired nozzle configurations will explicitly state primary or contingency. Without these indicators, mention of a repaired nozzle includes either configuration.

Note that Figure 1-2 and Figure 1-3 include a portion of the temporary coffer dam used in the repairs.

It is noted that Figure 1-4 and Figure 1-5 have been edited herein from Reference [2, 3, 4] to exclude the temporary mechanical plug and dimensions from the figure. The modifications for nozzles #30, #35, and #57 differ from the modifications performed for nozzle #48 in that the former will not include a roll expansion or boring step on the existing nozzle remnant.

The process will include the following steps per References [1, 2, 3, 4, 5, 6, 7, 8, 9]:

1.

cutting the existing thimble guide tube in two places below the BMI nozzle weld, 2.

removing a portion of the existing BMI nozzle below the RVBH, 3.

machining and roll expansion of the existing BMI nozzle remnant, o

Note that this step is not applicable to the modifications performed for BMI nozzles #30, #35, and

1. 57, machine application of an Alloy 52M temper bead weld pad on the outer surface of the RVBH around the penetration, machining the bore to receive a replacement Alloy 690 BMI half-nozzle, attaching the new half-nozzle to the weld pad with a J-groove partial penetration weld, attaching the existing TP304L thimble guide tube with a socket weld using Alloy 52M weld material to the Alloy 690 replacement half-nozzle, and attaching the two TP304L thimble guide tube segments with socket welds to a stainless steel coupling. A contingency coupling that is longer than the as-planned coupling may be used, but this has no effect on the results of this analysis.

As a contingency, instead of steps 7 and 8, a Type 304/304L contingency thimble guide tube fitting will be attached to the half-nozzle and the existing thimble guide tube segment via socket welds using Alloy 52M and ER308/308L weld materials, respectively.

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted instrument Nozzle Repairs The repaired configurations will expose low alloy steel (LAS) base metal of the RVBH to borated coolant at Locations A and B, see Figure 1-2 through Figure 1-5. Location A is the [

] Location B is [

] Note, a larger [

] Location A and Location B.

The purpose of this document is to evaluate potential material degradation via corrosion for the repaired configuration of nozzle #48. The evaluation will focus on 1) the LAS RVBH exposed due to the repairs, 2) the new pressure boundary nickel-based (Ni-based) alloy materials, 3) the affected stainless steel materials (i.e., guide tube near the repairs), and 4) components near the stainless steel thimble guide tube coupling or the contingency thimble guide tube fitting. For the exposed LAS, types of potential material degradation that will be considered include general corrosion, crevice corrosion, galvanic corrosion, stress corrosion cracking (SCC), hydrogen embrittlement, [

] The evaluation of the new Ni-based alloy components will focus primarily on primary water stress corrosion cracking (PWSCC) susceptibility. The focus of the evaluation of the affected stainless steel, specifically the thimble guide tube adjacent to the Alloy 52M socket welds and the stainless steel coupling or stainless steel contingency thimble guide tube fitting socket welds, will be SCC susceptibility.

The purpose of revision 001 is to include the repaired configurations of nozzles #30 and #35 in the evaluation performed herein.

The purpose of revision 002 is to include the repaired configuration of nozzle #57 and include the contingency thimble guide tube fitting repair configurations in the evaluation performed herein.

The purpose of revision 003 is to update the proprietary markings throughout the document.

The purpose of revision 004 is to extend the nozzle evaluations herein to span the remainder of the 60-year licensed operational life of the plant plus a 20-year operational life cycle extension and to update the proprietary markings concerning the Callaway chemistry program.

This evaluation does not address the remaining portion of the existing Alloy 600 nozzles or the existing Alloy 182 ID J-groove welds and buttering as they do not forma part of the pressure boundary following the repairs.

The corrosion evaluation will consider mechanisms applicable to the Callaway BMI nozzles #30, #35, #48, and

1. 57 in the repaired configurations for the life of the repairs, defined as the remainder of the 60-year licensed operational life of the plant plus a 20-year operational life cycle extension. The calculated general corrosion rate of the exposed LAS is applicable as long as [

J-GROOVE WELD AND BUTTERING Document No.: 51-9392748-003 ALLOY 182 SB-166, UNS NO6600 NOZZLE Y

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Figure 1-2:

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs Figure 1-3:

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Figure 1-5:

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Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzie Repairs ASSUMPTIONS Justified Assumptions The calculated combined corrosion rate in Section 4.2.1 is based on [

]

corrosion rates assigned for [

] Fora cycle length of [

]

are spent in each of these modes, respectively. [

]

] the impact on the calculated corrosion rates is considered [

]

NOTE: The combined corrosion rate remains applicable for a [

]

It is assumed that Callaway will maintain RCS primary water chemistry in accordance with EPRI PWR Primary Water Chemistry Guidelines during the life of the repairs. Continued validation of this assumption is performed through water chemistry program monitoring per the License Renewal Application [10, 11]. The utility has confirmed adherence to Revision 7 of the guidelines [12]. Off-chemistry excursions could impact the LAS general corrosion rate calculated herein and/or conclusions for other degradation mechanisms.

This assumption supports the application of the experimental corrosion rates established in Section 4.2.1 to the repaired configurations for the Callaway BMI nozzles #30, #35, #48, and #57. The modified lithium program, as noted in Reference [15], is not expected to invalidate this correlation.

3.

The calculated LAS corrosion rate in Section 4.2.1 is assumed to be conservative, based on the following:

rc 3.0 Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs The above positions justify the assumption of conservatism; the actual LAS general corrosion rate is expected to be bounded by that calculated in Section 4.2.1.

Assumptions Requiring Verification There are no assumptions requiring verification.

INDUSTRY OCCURRENCES OF EXPOSED CARBON/LOW ALLOY STEEL BASE METAL The carbon or LAS components in the pressurizer, reactor vessel (RV), and the steam generator (SG) exposed to PWR RCS primary coolant are clad with either stainless steel or Ni-based alloy in order to prevent corrosion of the carbon or LAS base metal. Throughout the operating history of domestic PWRs, there have been many cases where a localized area of the carbon or LAS base metal has been exposed to the PWR RCS primary coolant due to damage to the cladding or a repair configuration. Several such instances are listed below:

1960s 1990 Yankee-Rowe RV Surveillance capsules fell from holder assemblies to the bottom of the vessel, releasing test specimens and other debris, leading to perforations in the cladding.

Three Mile [sland Unit 1 (TMI-1) SG Several tubes were separated within the tubesheet due to SCC and repaired via explosive expansion. The repair exposed a small area in the tubesheet penetrations to primary coolant. (LER 289-1990-005)

Arkansas Nuclear One Unit 1 pressurizer A leak was detected at the pressurizer upper level tap nozzle within the steam space in December 1990. The repair consisted of removing the outer section of the nozzle followed by welding a new section of nozzle to the OD of the pressurizer. An axial crevice exists between the old and new nozzle sections, which exposes the pressurizer shell base metal to primary coolant. UT examinations from the pressurizer OD have revealed no indications of significant corrosion.

(LER 313-1990-021)

Oconee Unit 1 SG A mis-drilled tube-sheet hole in the upper tube-sheet of one of the SGs, during plugging operation in 1991, led to exposure of a small area of unclad tube-sheet to primary coolant.

[Note: This area of the tube-sheet has since been patched and is no longer exposed to coolant.]

McGuire Unit 2 RV A defect in the vessel cladding was discovered during an inspection in July 1993; the defect is believed to have occurred as a result of a pipe dropped in the vessel during construction (1975).

San Onofre Nuclear Generating Station Unit 2 hot leg nozzle A repair to a hot leg nozzle was completed during the 1993 outage at the SONGS Unit 2. This repair consisted of replacing a section of the existing Alloy 600 nozzle with a new nozzle section fabrication from Alloy 690. A gap approximately [

] wide exists between the two nozzle sections where the carbon steel base metal is exposed to the primary coolant. Verbal communication with SONGS personnel indicated that the hot leg nozzle containing this repair was removed and the exposed carbon steel examined.

Calvert Cliffs Unit 1 pressurizer Two leaking heater nozzles in the lower head of the pressurizer were partially removed and the penetrations were plugged in 1994.

(LER 317-1994-003)

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs Oconee Unit 1 Once Through Steam Generator (OTSG) manway During the end-of-cycle (EOC) 17 refueling outage, a degraded area was observed in the bore of the 1B OTSG. Subsequent inspection revealed a [

] circumferential damaged area to the cladding surface of the manway opening. The exposure of the base metal was confirmed by etching.

Control Rod Drive Mechanism (CRDM) repairs at Oconee Unit 2, Oconee Unit 3, Crystal River Unit 3, Three Mile Island Unit 1, and Surry Unit 1. (LER 270-2001-002, 287-2001-003, 302-200 1-004, 289-2001-002, 280-2001-003)

CRDM repairs at Oconee Unit 1 and Oconee Unit 2. (LER 269-2002-003, 270-2002-002)

CRDM/Control Element Drive Mechanism (CEDM) repairs at St. Lucie Unit 2 and Millstone Unit 2, half nozzle repairs of South Texas Project Unit 1 bottom mounted instrument nozzles, half nozzle repairs of pressurizer instrument nozzles at Crystal River Unit 3. (LER 389-2003-002, 498-2003-003, 302-2003-003) 2005 Half-nozzle modification for the TMI-1 pressurizer vent nozzle.

2013 Half-nozzle repair on RV bottom mounted instrument nozzle to the Palo Verde Unit 3.

(LER 2013-001-00) 2013 Framatome Inside Diameter Temper Bead (IDTB) half-nozzle repairs to the Harris CRDM nozzle penetrations. (LER 400-2013-001) 2017 Half-nozzle repair on RV head instrument nozzle after a leak was identified at Limerick Generating Station, Unit 2. (LER 2017-004-01) 2017 Catawba Unit 2, SG D hot leg channel head visual inspection identified an area of missing and/or thin cladding [14].

2020 Half-nozzle repair on RV instrument nozzle after a leak was identified at Peach Bottom Atomic Power Station Unit 2. (LER 2020-002-00) 2023 Nozzle repair on PZR thermowell after a boric acid leak was identified at PVNGS Unit 1.

(LER 50- 528/2023-002-00)

In most of these instances, carbon or LAS base metal was exposed to primary coolant in a localized area. Each plant returned to normal operation with the base metal exposed. Although some components were eventually replaced, the Yankee-Rowe vessel operated for approximately 30 years with the base metal exposed.

4.0 CORROSION OF LOW ALLOY STEEL EXPOSED TO RCS Several types of corrosion can occur when carbon steel and LAS base metal are exposed to primary coolant.

[

] The following sections discuss the possible corrosion mechanisms for the exposed LAS base metal at the repair Locations A and B, as depicted in Figure 1-2 through Figure 1-5.

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs 4.1 Methodology The Framatome methodology used to evaluate the potential for corrosion of the exposed LAS due to these repairs is as follows:

e Wastage of General Corrosion o

[

Crevice Corrosion o

[

Galvanic Corrosion o

[

]

Stress Corrosion Cracking o

[

Hydrogen Embrittlement o

4.2 General Corrosion General corrosion is defined as uniform deterioration of a surface by chemical or electrochemical reactions with the environment, Austenitic stainless steels and Ni-based alloys (e.g. wrought Type 304, Type 316, Alloy 600, and Alloy 690 materials and their equivalent weld metals) are virtually immune to general corrosion from exposure to PWR primary coolant. Carbon steel and LASs, however, may be subject to general corrosion upon exposure to primary coolant. The general corrosion rates of carbon steel and LASs during aerated and deaerated reactor coolant conditions are discussed below.

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs 4.2.1 General Corrosion Data Many studies [16, 17, 18, 19, 20, 21, 22, 23, 24, 25] have reported corrosion rates of carbon steel and LASs in high temperature water.

In many studies, the corrosion rates for carbon steel and LASs have been observed to be similar; the corrosion data [17, 18, 21, 24, 25} includes carbon steel and LASs such as ASME SA-212 and SA-302 Grade B. The material of the Callaway RVBH (SA-533 Grade B Class 1 [1]) is essentially equivalent to SA-302 Grade B, except that SA-533 Grade B Class 1 also includes some nickel. Nickel has no deleterious effect on the general corrosion of LAS, so the referenced corrosion data is considered applicable to the Callaway RVBH. The Electric Power Research Institute (EPRD has also compiled a handbook [26] on boric acid corrosion (BAC). This handbook summarizes the industry field experience with BAC incidents, contains a discussion of BAC mechanisms, and contains a compilation of prior BAC testing and results.

One evaluation was completed in response to the Yankee-Rowe incident (noted in Section 3.0); in the evaluation, A-212 carbon steel was exposed to primary coolant in aerated and deaerated conditions [27].

It was shown that under deaerated conditions (i.e., during operation), the corrosion rate depended on temperature, fluid velocity, boric acid concentration, and time. At the maximum velocity tested (36 ft/sec.), the corrosion rate was determined to be 0.003 ipy the maximum corrosion rate reported [27]. Under low flow or stagnant conditions at 650°F, a maximum corrosion rate of 0.0009 ipy was reported.

In the same study under shutdown conditions (aerated, low temperature [~70°F]), the maximum corrosion rate was determined to be 0.0015 inch for a two-month shutdown, or 0.009 ipy [27]. The slow corrosion rates from this test data are consistent with the operating experience of LAS exposed to PWR primary coolant (partial list provided in Section 3.0) in that no issues have been reported regarding these locations.

[

Table 4-1:

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessei Bottom Mounted Instrument Nozzle Repairs 4.2.2 Pressure Boundary Leakage (Wastage)

For the primary coolant inside the repaired BMI nozzle penetrations, there is no mechanism for boric acid to concentrate due to the new pressure boundary material removing the leak path. [

] As indicated in Section 4.2.1, test data of LAS exposed to borated water similar to primary coolant shows very slow corrosion rates relative to wastage, which can be greater than one inch/year [26]. [

]

It is noted a pressure boundary leak was discovered at BMI nozzle #48 during the 2025 (R27) Mode 3 startup leak check visual inspection at Callaway, but absence of this leak previously supports the argument that wastage has not already occurred. Since this evaluation is only concerned with LAS corrosion exposed to the primary coolant,

[

]

4.2.3 Long Term General Corrosion 4.3 Crevice Corrosion The environmental conditions in a crevice can become aggressive with time and can cause accelerated local corrosion. Experiments were conducted to study crevice corrosion of LAS in primary coolant. The results showed no evidence of increased corrosion in the crevices for both aerated and deaerated conditions (i.e., crevice corrosion could not be distinguished from general corrosion) [21, 27]. [

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzie Repairs

]

4.4 Galvanic Corrosion Galvanic corrosion may occur when two dissimilar metals in contact are exposed to a conductive solution. The larger the electrochemical potential difference between the two metals, the greater the likelihood of galvanic corrosion. Low alloy steel is more anodic than Ni-based weld metals (Alloy 52M) and could therefore be subject to galvanic attack when coupled and exposed to reactor coolant, as in the repaired configurations.

Several corrosion tests were performed to determine the influence of coupling between low alloy and austenitic stainless steel, which has approximately the same corrosion potential as Ni-based alloys. In one test, LASs were coupled (i.e., welded) to stainless steels exposed to high purity water for 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> at 546°F in steam, steam/water, saturated water, and sub-cooled water in aerated and deaerated conditions [16]. The coupled specimen did not exhibit any accelerated rates of corrosion. Specimens made from 5% chromium steel coupled to Type 304 stainless steel were exposed to aerated water at 500°F for 85 days (~2000 hours) and 98 days (~2300 hours) with no evidence of galvanic corrosion [25].

In each of the tests described above, corrosion rates were not affected by coupling.

The results of the NRCs boric acid corrosion test program at Argonne National Laboratory have shown that the galvanic difference between ASTM A533 Grade B LAS, Alloy 600, and Type 308 stainless steel (used in reactor vessel cladding) is not significant enough to consider galvanic corrosion as a strong contributor to the overall BAC process [29].

This is supported by many cases of LAS coupled to stainless steel or Ni-based alloys being exposed to primary coolant (see Section 3.0 for a partial list) without reported accelerated corrosion relative to what is expected for general corrosion. Given the lack of evidence for galvanic corrosion for LAS when coupled to Ni-based alloys or austenitic stainless steel in PWR environments, galvanic corrosion is not expected to be a concern for the repaired configurations.

4.5 Stress Corrosion Cracking Stress corrosion cracking (SCC) can occur only when the following three conditions are present: 1) a susceptible material, 2) a tensile stress, and 3) an aggressive environment.

Numerous laboratory studies have been performed on carbon steel and LASs to assess their susceptibility to SCC in various aqueous environments. Most of these studies, which have been performed on reactor materials in light water reactor (LWR) environments, have been coordinated under the auspices of the International Cyclic Crack Growth Rate (ICCGR) Group. While this group has focused its attention on corrosion fatigue, much of the work over the past two decades has also been on SCC. A review of the work conducted through 1990 appears in a paper by Scott and Tice [30]. A more recent review of the relevant laboratory work and field experience appears in a report prepared for the CE Owners Group [31]. The conclusions of both evaluations are the same, i.e.,

Page 20

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs considering the environmental conditions present in a PWR, low alloy and carbon steel will not be subject to SCC unless they experience some prolonged departure from expected normal operation conditions, which is not permitted by the water chemistry guidelines. The results of these evaluations have been supported by several subsequent laboratory studies [32, 33, 34, 35].

Extensive PWR (see Section 3.0) and boiling water reactor (BWR) [35] operating experience related to LAS being exposed to reactor coolant has not resulted in OE for SCC of LAS reactor pressure vessel material to any significant depth. Noteworthy are SCC cracks revealed in the stainless steel cladding in charging pumps [36, 37].

The interdendritic cracks, present in the cladding, were determined to have blunted at the clad/LAS interface.

Stress corrosion cracking of the exposed LAS is not expected for the repaired configurations.

4.6 Hydrogen Embrittlement Hydrogen embrittlement in LASs results from excessive amounts of hydrogen in a metal's crystal lattice. This type of damage is a mechanical/environmental failure process, which usually occurs in combination with residual or applied stresses. Hydrogen embrittlement is observed most often in plastically deformed metals or alloys in high pressure hydrogen environments and is characterized by ductility losses and lowering of the fracture toughness. High pressure hydrogen environments are not typical of PWR systems and are defined as an environment with approximately 5,000-10,000 psi [38]. Hydrogen exists within the reactor coolant system (used as an oxygen scavenger) and is expected to accumulate at locations such as the top of the pressurizer. Hydrogen-induced mechanical property changes are more pronounced in high-strength low-toughness steels. Low-strength high-toughness steels such as SA-212, SA-302, or SA-533 are little affected by hydrogen in this manner [16].

In the case of a PWR RV under normal operation, the corrosion rate and diffusion rate of hydrogen through the vessel wall are such that the maximum hydrogen concentration in the steel of the lower head is approximately 0.3 parts per million (ppm) [16].

In either case, the quantity of hydrogen that may accumulate at locations within the coolant system is not expected to induce hydrogen embrittlement in materials at those locations.

Therefore, hydrogen embrittlement is not expected to be a concern for the exposed LAS.

47

[

]

Page 21

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs 5.0 CORROSION OF ALLOY 690 AND ALLOY 52M The following subsections discuss the potential corrosion mechanisms for the Alloy 690 half-nozzle and Alloy 52M weld metal (weld pad, J-groove weld, and socket weld) shown in Figure 1-2 through Figure 1-5.

5.1 General Corrosion General corrosion is defined as uniform deterioration of a surface by chemical or electrochemical reactions with the environment. Ni-based alloys (e.g., Alloy 600, Alloy 690, and their equivalent weld metals) are utilized in PWR and BWR systems because they are essentially immune to general corrosion due to the formation of a passivating film of various iron, nickel, and chromium oxides [40]. The potentially aerated environment in the RCS during shutdown will be more akin to a BWR environment. To date, there have been no reported instances of issues arising from general corrosion of Alloy 690 in BWR environments, so general corrosion is not expected to be a concern for this alloy for the life of the BMI nozzles #30, #35, #48, and #57 modifications. [

] Although general corrosion may be present, these corrosion rates for Ni-based alloys are small and are not expected to be of concern for the repairs.

5.2 Crevice Corrosion The proposed repairs to the BMI nozzles will create crevice conditions (high aspect ratio) associated with the Alloy 690 nozzle (Location B). However, these Ni-based alloys in general have excellent resistance to general and crevice corrosion under typical PWR conditions [42, 43]. For the life of the repairs, crevice corrosion is not considered a concern for Alloy 690.

5.3 Galvanic Corrosion Galvanic corrosion may occur when two different metals in contact are exposed to a conductive solution. As discussed in Section 4.4, galvanic corrosion between LAS and Alloy 690 or Alloy 52M in the PWR environment is not expected to be a concern for the life of the repairs.

5.4 Low Temperature Crack Propagation Low temperature crack propagation (LTCP) occurs in Ni-based alloys and is considered a form of hydrogen embrittlement. This type of damage is characterized by a reduction in fracture toughness when exposed to water (particularly hydrogenated) at low temperatures (below 150°C (302°F)). This phenomenon starts from pre-existing sharp cracks, with hydrogen at grain boundaries, and at stress intensity levels greater than a critical value.

While RCS temperatures in the shutdown and startup conditions are low enough to induce LTCP in very high pressure hydrogen environments, such environments are not typical of PWR systems [44]. Therefore, LTCP is not expected to be a concern for Alloy 690 or Alloy 52M for the life of the repairs.

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs 5.5 Stress Corrosion Cracking Alloy 52M is a modified version of Alloy 52 for improved weldability, but this variation is similar to Alloy 52 in terms of the PWSCC resistance properties discussed below [45]. The corrosion resistance of Alloy 690 and weld metal Alloys 52 and 152 has been extensively studied as a result of numerous PWSCC failures in mill annealed Alloy 600 and weld metals Alloys 82 and 182 in primary water environments. As a result of Alloy 600 and Alloys 82 and 182 failures, Alloy 690 and Alloys 52/152 have been chosen by the nuclear power industry as the replacement material of choice for Alloy 600 and Alloy 82/182 components and welds in PWRs.

A comprehensive review of testing for the use of Alloy 690 and Alloy 52 in PWRs cites numerous investigations and test results under a wide array of conditions, including both primary (high temperature de-oxygenated water) and secondary coolant environments [46]. The first Alloy 690 SG went on-line in May 1989 with no reported failures of tubes due to environmental degradation as of an August 1997 literature review [47]. At the time of this evaluation, there are no known reports of Alloy 690 in-service PWSCC failures. The typical test conditions cited in the Alloy 690 literature review included temperatures up to 365°C (689°F), dissolved oxygen levels < 20 parts per billion (ppb), in doped and undoped 400°C (752°F) steam, lithium concentrations up to 20 ppm, chlorides up to 300 ppb, and various heat treatments of Alloy 690. Reverse U-bend SCC tests within the above matrix of environmental conditions produced no PWSCC in Alloy 690. No cracking was observed in high purity water containing 16 ppm oxygen at 288°C (550°F), even in a crevice situation. Only slight intergranular cracking of Alloy 690MA (mill annealed) was observed in slow strain rate testing (SSRT) in 360°C (680°F) high purity deaerated hydrogenated water. However, the same cracking was also observed in tests under argon, so the cracking observed in high purity deaerated hydrogenated water could not be confirmed to be PWSCC [47].

The SCC resistance of weld metals Alloy 52 and 152 was identified as unaffected by a variety of test conditions, including primary water. No cracking occurred in weld metals containing > 22% chromium [47]. Constant extension rate test (CERT) data is available for specimens fabricated from weld mockups made from Alloys 690, Alloy 52, Alloy 152, and Alloy 82 and tested under normal and faulted (addition of 150 ppb chloride) primary water conditions. The water chemistry was typical primary water: 2.2 ppm Li, 1000 ppm B, 6.5 pH, > 20 cc/kg hydrogen. Neither the weld mockups nor the CERT specimens were stress relieved after the Alloy 152 weld prior to testing. The test temperature was 343°C (650°F), with tests performed at a constant strain rate of either 1x10° or 5x10° sec. No evidence of SCC failures was observed on any specimens tested at the faster strain rates, only dimpled rupture fracture surfaces indicating ductile failure were reported. The results of the slower strain rate

(~10° sec") tests did show evidence of SCC failure in the Alloy 82 weld metal, but not in Alloy 690 or Alloy 152.

These tests demonstrate the high SCC resistance of Alloy 690 and Alloy 152 weld metal under the conditions of high stress, which include residual stresses from welding, machining, and high plastic straining of the test specimens [48].

Stress corrosion cracking test data comparing results between Alloy 690 and Alloy 600 is available in both aerated and deaerated high temperature water. Test specimens were made from a creviced double U-bend geometry and were tested for 48 weeks at 316°C (601°F). Various Alloy 690 material conditions were tested, including MA, MA+ thermal treatment (TT), MA followed by solution annealing (SA), cold working (cold rolled 40%), and gas tungsten arc welding (GTA W) welded specimens with matching filler metal.

In tests with an environment of a minimum of 6 ppm dissolved oxygen and pH of 10, the control alloys, including Alloy 600 and Alloy 800 readily cracked, whereas Alloy 690 showed no cracking. Additional tests were carried out under deaerated conditions (~ 20 ppb O2) where Alloy 690 showed no cracking, while Alloy 600 in the MA + cold roll heat treated condition cracked. Consistent with other investigators previously cited, Alloy 690TT showed a resistance to cracking. Additional tests were carried out at 360°C (680°F) in deaerated water with a pH of 10 as part of the same study. Alloy 690 material test conditions included SA (1010°C [1850°F] and 1120°C [2048°F])

and SA+TT (1120°C [2048°F]) + TT (675°C [1247°F]). Again, no cracking of Alloy 690 was reported [49].

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs Some studies have indicated that Alloy 690 SCC crack growth rates (CGRs) can increase dramatically if extensive cold work (especially non-uniform cold work, such as unidirectional rolling) is present [50, 51].

Extensive cold work is not thought to generally be representative of plant components [51], and [

]

Based on these studies examining the PWSCC of Alloy 690 and Alloy 52M weld metal, it can be concluded that these alloys have a low susceptibility to PWSCC.

It is expected that the Alloy 690 nozzle and Alloy 52M J-groove weld and weld pad in this modification will have superior PWSCC performance to the existing Alloy 600 nozzle and Alloy 182 weld material. Therefore, PWSCC of Alloy 690 and Alloy 52M is not considered to be a concern for the life of the repairs.

6.0 SCC SUSCEPTIBILITY OF STAINLESS STEEL THIMBLE GUIDE TUBE ADJACENT TO THE ALLOY 52M SOCKET WELD Stress corrosion cracking requires three synergistic elements to occur: 1) sustained tensile stress, 2) an aggressive (corrosive) environment and 3) a susceptible material. In the case of austenitic stainless steel in a reactor environment, aerated water is considered an aggressive environment. Austenitic stainless steels are generally susceptible to SCC in elevated temperature environments where impurities such as halogens (e.g., chlorides and fluorides) and/or dissolved oxygen are present or when significantly cold worked. Cracking can occur as intergranular stress corrosion cracking (IGSCC) or transgranular stress corrosion cracking (TGSCC) under these conditions.

Original Configuration The original BMI nozzle penetration configuration (Figure 1-1) included Alloy 82/182 socket welds between the Alloy 600 BMI nozzles and the SA-213 TP304L thimble guide tubes [1, 5, 6]. There is no known (to Framatome) leaking of the piping adjacent to the existing socket welds, despite weld residual stresses being present adjacent to the weld within the existing piping. Thus, either one of the remaining synergistic elements, and potentially both, required for SCC of the piping material (susceptible material and/or aggressive environment) are concluded to be possibly absent in the existing configuration. Owing to the sensitization resistance afforded by the low-carbon grade (less than 0.030 weight percent carbon), the thimble guide tube material is most likely not sensitized in the region adjacent to the socket welds.

Repaired Configurations As shown in Figure 1-2 and Figure 1-4, the repair to BMI nozzle penetrations will include an Alloy 52M socket weld joining the existing SA-213 TP304L stainless steel thimble guide tubes (or, as shown in Figure 1-3 and Figure 1-5 a contingency replacement SA-479 Type 304/304L thimble guide tube, if the existing ones cannot be used [1]) to the new Alloy 690 nozzles. Although the Alloy 52M weld material was considered by Section 5.5, the impact of the socket weld on the replacement instrumentation piping is considered herein.

For the thimble guide tubes, the susceptibility to SCC will be managed by demonstrating that each of the contributing elements is expected to be similar to the existing configuration:

)

Page 24

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs l

For the thimble guide tube adjacent to the Alloy 52M socket weld at the point of attachment to the new nozzle, the three synergistic elements required for SCC are managed such that SCC susceptibility is expected to be the same as or less than that of the existing configuration for the aforementioned reasons.

Based on industry experience, [

] This mechanism is not considered environmental degradation and, therefore, is outside the scope of this evaluation.

7.0 SCC SUSCEPTIBILITY OF STAINLESS STEEL COMPONENTS NEAR THE COUPLING As shown in Figure 1-2 and Figure 1-4, the original thimble guide tube segment (SA-213 TP304L) is cut into two pieces, which will then be joined together using a coupling (SA-479 304/304L) and two socket welds (Type ER308/308L).

The location of the coupling is expected to be [

] the nozzle to thimble guide tube socket weld, see Figure 1-2 and Figure 1-4 [5, 6], so the potential for elevated dissolved oxygen and contaminants (e.g.,

chlorides) at the thimble guide tube to stainless steel coupling socket welds is [

]

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzie Repairs Thimble Guide Tube and Coupling Material Adjacent to Coupling Socket Welds As noted in Section 6.0, [

]

is applicable for the BMI nozzle repairs [1].

It is reasonable to expect the qualified weld procedures for the repairs, [

]

to effectively manage the risk of sensitization within the thimble guide tube and coupling, specifically adjacent to the socket welds. The couplings and thimble guide tubes are both low carbon (<0.030 weight percent) grades, which is notable due to increased resistance to sensitization. Based on the low carbon content and qualified weld practices, SCC is not expected for the coupling or tubing adjacent to the socket welds for the life of the repairs.

For the contingency repair configurations (see Figure 1-3 and Figure 1-5), the contingency thimble guide tube fitting is a low carbon (<0.030 weight percent) grade. Therefore, the above evaluation is also applicable for the contingency repair configurations.

Coupling Socket Welds Again, [

] is applicable for the BMI nozzle repairs [1]. It is reasonable to expect the qualified weld procedures for the repairs, [

] to effectively manage the risk of sensitization for the weld material in the socket welds attaching the thimble guide tube section with the stainless steel coupling.

Additionally, the ER308/308L weld metal to be used for the coupling socket welds will have a [

] Austenitic stainless steel welds typically contain about 5-10% ferrite to prevent hot cracking during solidification. In hot, aqueous chloride containing environments, these weld metals generally show a marked resistance to SCC, while their base metal counterparts readily crack. The generally accepted explanation for this behavior is that the ferrite phase is resistant to chloride SCC, which impedes crack propagation through the austenite phase. [

]

] Additionally, socket welds ofa similar design were performed as part of a similar BMI nozzle half-nozzle repair [56] and no environmental degradation of this socket weld has been reported after approximately 11 years of service.

Therefore, SCC of the weld metal in the thimble guide tubes to stainless steel coupling welds is not expected for the life of the repairs.

For the contingency repair configurations (see Figure 1-3 and Figure 1-5), the weld metal is the same as noted above (Type ER308/308L) and the base metals in the primary and contingency repair configurations are both low carbon (<0.030 weight percent) grades. Therefore, the above evaluation is also applicable for the repair configurations.

As stated in Section 6.0, based on industry experience, [

] This mechanism is not considered to be environmental degradation and, therefore, is outside the scope of this evaluation.

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs

8.0 CONCLUSION

S The information presented above describes the potential corrosion mechanisms that may affect the Callaway BMI nozzle penetrations #30, #35, #48, and #57 in the repaired configurations (both primary and contingency) for the life of the repairs, defined as the remainder of the 60-year licensed operational life of the plant plus a 20-year operational life cycle extension.

For the LAS exposed to the primary coolant by these repairs, crevice corrosion, galvanic corrosion, SCC, hydrogen embrittlement, [

]

are not expected to be a concern for the life of the repairs. Based on industry data and Framatomes experience, the general corrosion rate of exposed LAS for BMI nozzles #30, #35, #48, and #57 in the repaired configurations (both primary and contingency) [

]

Extensive literature and operating experience indicate that it is very unlikely the Alloy 690 and Alloy 52M material used for the BMI nozzle penetration #30, #35, #48, and #57 repairs (both primary and contingency) will degrade from exposure to the primary coolant during the life of the repairs.

Based on the conditions expected at the areas of interest, operating experience, and laboratory studies, SCC of the stainless steel thimble guide tube sections adjacent to the socket welds, the stainless steel couplings and/or contingency thimble guide tube fittings, and the socket welds is not expected to occur during the life of the repairs.

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs

9.0 REFERENCES

References identified with an (*) are maintained within Callaways Records System and are not retrievable from Framatome Records Management. These are acceptable references per Framatome Administrative Procedure 0402-01, Attachment 7. See page [2] for Project Manager Approval of customer references.

[

]

License Renewal Application, Callaway Plant Unit 1, Facility Operating License No. NPF-30. Accession No. ML113530372.

NUREG-2172, Safety Evaluation Report Related to the License Renewal of Callaway Plant, Unit 1, Docket Number 50-483, March 2015. Accession No. ML15068A342.

• Pressurized Water Reactor Primary Water Chemistry Guidelines: Revision 7, Volumes 1 and 2, EPRI, Palo Alto, CA: 2014. 3002000505.

Hall, J.F., Frisk, R.S.,

ONeill, A.S., Pathania, R.S., and Neff, W.B., Boric Acid Corrosion of Carbon and Low Alloy Steels, Fourth International Symposium on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors, p.9-38, 1989.

Duke Energy Carolinas, LLC, Duke Energy Carolinas, LLC (Duke Energy), Catawba Nuclear Station (CNS), Unit 2, Facility Operating License Number NPF-52, Docket Number 50-414, End of cycle 21 Refueling Outage Inservice Inspection Report and Steam Generator Inservice Inspection Summary Report, Response to NRC Requests for Additional Information (RAIs), May 24, 2017, NRC Accession Number ML17146A907.

• APA-ZZ-01020, Revision 036, Primary Chemistry Program.

Whitman, G. D. et. al.,

A Review of Current Practice in Design, Analysis, Materials, Fabrication, Inspection, and Test, ORNL-NSIC-21, ORNL, December 1967.

Controlled Document framatome l

Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs Vreeland, D. C. et. al., Corrosion of Carbon and Low-Alloy Steels in Out-of-Pile Boiling Water Reactor Environment, Corrosion, v17, June 1961, p. 269.

Vreeland, D. C. et. al., Corrosion of Carbon Steel and Other Steels in Simulated Boiling-Water Reactor Environment: Phase II, Corrosion, v18, October 1962, p. 368.

Uhlig, H. H., Corrosion and Corrosion Control, John Wiley & Sons, New York, 1963.

Copson, H. R., Effects of Velocity on Corrosion by Water, Industrial and Engineering Chemistry, v44, No. 8, p. 1745, August 1952.

Vreeland, D. C., Corrosion of Carbon Steel and Low Alloy Steels in Primary Systems of Water-Cooled Nuclear Reactors, Presented at Netherlands-Norwegian Reactor School, Kjeller, Norway, August 1963.

Pearl, W. L. and Wozadlo, G. P., Corrosion of Carbon Steel in Simulated Boiling Water and Superheated Reactor Environments, Corrosion, v21, August 1965, p. 260.

DePaul, E. J., Corrosion and Wear Handbook for Water-Cooled Reactors, McGraw-Hill Book Company, Inc. 1957.

Tackett, D. E. et. al., Review of Carbon Steel Corrosion Data in High-Temperature Water, High-Purity Water in Dynamic Systems, USAEC Report, WAPD-LSR(C)-134, Westinghouse Electric Corporation, October 14, 1955.

Ruther, W. E. and Hart, R. K., Influence of Oxygen on High Temperature Aqueous Corrosion of Iron, Corrosion, v19, April 1963, p. 127.

• Materials Reliability Program, Boric Acid Corrosion Guidebook, Revision 2: Managing Boric Acid Corrosion Issues at PWR Power Stations (MRP-058 Rev 2), EPRI, Palo Alto, CA: 2012. 1025145.

Evaluation of Yankee Vessel Cladding Penetrations, Yankee Atomic Electric Company to the U. S.

Atomic Energy Commission, WCAP-2855, License No. DPR-3, Docket No. 50-29, October 15, 1965.

[

NUREG-1823, U.S. Plant Experience With Alloy 600 Cracking and Boric Acid Corrosion of Light-Water Reactor Pressure Vessel Materials, March 2005.

P.M. Scott and D.R. Tice, "Stress Corrosion in Low Alloy Steels", Nuclear Engineering and Design, Volume 119, 1990.

J.F. Hail, "Low-Alloy Steel Component Corrosion Analysis Supporting Small-Diameter Alloy 600/690 Nozzle Repair/Replacement Programs", CE NPSD-1198-NP, Revision 00, February 15, 2001, Non-Proprietary version available for viewing on the NRC website (ML010540212).

M. Herbst, et al., Effect of Chloride on Environmentally Assisted Cracking of Low Alloy Steels in Oxygenated High Temperature Water General Corrosion, 15th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors.

T. Kubo, et al., SCC Retardation and Propagation Behavior in Dissimilar Weldment of Alloy 182 and Low Alloy Steel, 14th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors.

A. Roth, et al., The Effect of Transients on the Crack Growth Behavior of Low Alloy Steels for Pressure Boundary Components under Light Water Reactor Operating Conditions, 12th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors.

Page 29

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs H. Abe, et al., Stress Corrosion Cracking Behavior Near the Fusion Boundary of Dissimilar Weld Joint with Alloy 182-A533B Low Alloy Steel, 15th International Conference on Environmental Degradation of Materials in Nuclear Power Systems-Water Reactors.

Information Notice No. 80-38, Cracking in Charging Pump Casing Cladding, Nuclear Regulatory Commission, October 31, 1980.

Information Notice No. 94-63, Boric Acid Corrosion of Charging Pump Casing Cause by Cladding Cracks, Nuclear Regulatory Commission, August 30, 1994.

Gray, H.H., Hydrogen Embrittlement Testing (STP 543), Opening Remarks, 1974. ASTM.

Wang, Y., Song, S., Wang, J., Behnamian, Y., Xu, L., Fan, H., and Xia, D.H., Correlation between Passivity Breakdown and Composition of Passive Film Formed on Alloy 690 Studied by Sputtering XPS and FIB-HRTEM, J. Electrochem. Soc., Vol. 166, 2019.

[

]

Crum, J.R., and Nagashima, T., Review of Alloy 690 Steam Generator Studies, Eighth International Symposium on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors, August 1997, Amelia Island, Florida, ANS.

Saito, N., Crevice Corrosion of Austenitic Alloys in High-Temperature Water, Corrosion, Vol 54(9),

p. 700, September 1998.

Demma, A., Mcllree, A., and Herrera, M., Low Temperature Crack Propagation Evaluation in Pressurized Water Reactor Service, 12th International Conference on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors, 2005.

R. Zhang, et al., New 30% Chromium-containing Ni-Cr-Fe Welding Product Provides Outstanding Resistance to PWSCC, Ductility Dip Cracking (DDC) and Meets All Other Nuclear Welding Requirements, C2012-0001743, NACE International, Corrosion 2012 Conference and Expo, Salt Lake City, UT.

Materials Reliability Program, Resistance to Primary Water Stress Corrosion Cracking of Alloys 690, 52, and 152 in Pressurized Water Reactors (MRP-111), EPRI, Palo Alto, CA: 2004. 1009801.

Crum, J.R., Nagashima, T., Review of Alloy 690 Steam Generator Studies, Eighth International Symposium on Environmental Degradation of Materials in Nuclear Power Systems

~ Water Reactors, Aug. 10-14, 1997. Amelia Island, FL, ANS.

Psaila-Dombrowski, M.J., et al., Evaluation of Weld Metals 82, 152, 52, and Alloy 690 Stress Corrosion Cracking and Corrosion Fatigue Susceptibility, Eighth International Symposium on Environmental Degradation of Materials in Nuclear Power Systems Water Reactors, Aug. 10-14, 1997.

Amelia Island, FL, ANS.

Sedriks, A.J., Schultz, J.W., Cordovi, M.A., Inconel Alloy 690 A New Corrosion Resistant Material, Boshoku Gijutsu, Japan Society of Corrosion Engineering, V28(2), 1979.

Materials Reliability Program: Resistance to Primary Water Stress Corrosion Cracking of Alloy 690 in Pressurized Water Reactors (MRP-258). EPRI, Palo Alto, CA: 2009. 1019086.

Materials Reliability Program: Recommended Factors of Improvement for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) Growth Rates of Thick-Wall Alloy 690 Materials and Alloy 52, 152, and Variants Welds (MRP-386). EPRI, Palo Alto, CA: 2017. 3002010756.

Page 30

Controlled Document framatome Document No.: 51-9392748-003 Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repairs

]

Palo Verde Relief Request 52 Proposed Alternative in Accordance with 10 CFR 50.55a(a)(3)(i),, Corrosion Evaluation for Palo Verde Unit 3 Reactor Vessel BMI Nozzle Modification, April 18, 2014. Accession No. ML14149A342.

Controlled Document 0402-01-F01 (Rev. 023, 06/20/2024) framatome CALCULATION

SUMMARY

SHEET (CSS)

oe La

ant Document No.

32 9392644 003 Safety Related:

Dives C1 No Title Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35and 57 PURPOSE AND

SUMMARY

OF RESULTS:

PURPOSE:

During the Spring 2025 outage (R27) at Callaway Unit 1, the Reactor Vessel Bottom Head (RVBH) Bottom Mounted Instrumentation (BMI) Nozzle No. 48 is being repaired due to reactor coolant leakage at the interface between the RVBH and BMI nozzle. Additionally, indications were found in the J-groove welds at the BMI Nozzles No. 30, 35, and 57 locations. The purpose of this evaluation is to perform a fracture mechanics one cycle justification (OCJ) to assess the suitability of leaving the original, as-left J-groove weld (ALJGW) in the RVBH. This assessment considers a postulated radial corner flaw extending beyond the butter-to-RVBH interface to include the transition from tensile to compressive weld residual stresses. Flaw growth is then considered for one cycle beyond the repair in 2025. An existing flaw assessment for a similar location in another plant with comparable design and loading conditions is used to qualitatively justify that the postulated flaw is acceptable for one cycle beyond the repair. In addition, a limit load analysis is done to satisfy the requirements of Article IWB-3610(d)(2). This analysis demonstrates that the primary stress limits of Article NB-3000 are met, assuming a local area reduction of the pressure-retaining membrane that is equal to the area of the projected flaw. Since this analysis is not included in the existing ALJGW flaw evaluation, it provides the necessary validation for the repair and continued operation of the RVBH.

Rev. 001: Provide justification that the analysis in Rev. 000 is applicable to the modification of Nozzles 48, 30 and 35.

Rev. 002: Provide justification that the analysis in Rev. 000 is applicable to the modification of Nozzles 48, 30, 35 and 57.

Rev. 003: Update markups for proprietary information to line up with the Relief Request submitted to NRC.

Rev. 004: Update markups for proprietary information to incorporate NRC comments.

SUMMARY

OF RESULTS:

Based on the comparative analysis between Callaway and an existing RVBH BMI nozzle repair ALJGW evaluation for a similar plant documented in Reference [3], it is demonstrated that the 2019 ASME B&PV Code,Section XI, IWB-3612 requirements are met for one fuel cycle (18 months) beyond the repair in 2025. To satisfy the requirements of Article IWB-3610(d)(2), the primary stress requirements of the 2015 ASME B&PV Code,Section III, Article NB-3000 are met by limit analysis. This evaluation considers a local area reduction of the pressure retaining membrane of the nozzle opening that includes the area of the ALJGW and flaw growth for one cycle.

Rev. 001: The evaluation in Rev. 000 is applicable to modification of BMI Nozzles 48, 30 and 35.

Rev. 002: The evaluation in Rev. 000 is applicable to modification of BMI Nozzles 48, 30, 35 and 57.

Rev. 003: Results from Rev. 002 remain unchanged.

Rev. 004: Results from Rev. 002 remain unchanged.

Proprietary information in the document is identified by bold brackets ([ ]). The content of this document is identical to 32-9392642-004, except that proprietary information is redacted. Any Rev. 001, Rev. 002, Rev. 003, or Rev. 004 herein refers to that in 32-9302642.

l Export Classification USEC:

ON W& Part810 O EAR

[ECCN: N/A If the computer software used herein is not the latest version per the EASI list,

~

AP 0402-01 requires that justification be provided.

aoaNeCONES NOR TDUSS THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:

CODE/VERSION/REV CODE/VERSION/REV oo

ue r] Yes ANSYS v19.2 (See Section 5.1)

Page 1 of 24

Controlled Document 0402-01-F01 (Rev. 023, 06/20/2024) framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 Review Method:

Design Review (Detailed Check)

[ ] Alternate Calculation Does this document establish design or technical requirements?

[l YES NO Does this document contain Customer Required Format?

[l YES NO Signature Block Name and Title Signature and Date l Role l

Scope / Comments

. Kaihong Wang K WANG P

Advisory Engineer 9/24/2025 l

Martin Kolar M KOLAR Principal Engineer 9/24/2025 l

Bogdan Wasiluk BS WASILUK Supervisor

• 9/24/2025 Role Definitions:

P/R/A designates Preparer (P), Reviewer (R), Approver (A);

LP/LR designates Lead Preparer (LP), Lead Reviewer (LR);

M designates Mentor (M);

PM designates Project Manager (PM)

Controlled Document 0402-01-F01 (Rev. 023, 06/20/2024) framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 Record of Revision Revision l Parayraphe Changed l

Brief Description / Change Authorization Initial release. The content of this document is identical to

_32-9392642-000, except that proprietary information is redacted.

The content of this revision is identical to 32-9392642-002, except All that proprietary information is redacted and the Record of Revision is

_eliminated. See Record of Revision in 32-9392642-002 for changes.

- The content of this revision is identical to 32-9392642-003, except

' that proprietary information is redacted and the Record of Revision is eliminated. See Record of Revision in 32-9392642-003 for changes.

The content of this revision is identical to 32-9392642-004, except that proprietary information is redacted and the Record of Revision is eliminated. See Record of Revision in 32-9392642-004 for changes.

All

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 Table of Contents 1.0 2.0 3.0 ANALYTICAL METHODOLOGY 3.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612) 3.2 Primary Stress Limits (NB-3000)

ASSUMPTIONS l

Unverified Assumptions 4.2 Justified Assumptions 4.3 Modeling Simplifications 5.1 5.2 CALCULATIONS 6.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612) 6.1.1 Key Dimension Comparison 6.1.2 l Material and Property Comparison 6.1.3 Initial Flaw Size and Weld Residual Stress Comparison 6.1.4 Roll Expansion Evaluation 6.1.5 Operational Transient Condition Comparison 6.1.6 l General Corrosion and Fatigue Crack Growth Comparison 6.1.7 ASME Section XI Code Edition Comparison 6.2 Primary Stress Limit Evaluation (ASME B&PV Code Section III NB-3000) 6.3 OCJ Extended to Nozzles 30 and 35 6.4 OCJ Extended to Nozzle 57

SUMMARY

OF RESULTS REFERENCES

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 List of Tables Table 5-1: Computer Files Table 6-1: Key Dimensions Comparison Table 6-2: Material Comparison Table 6-3: Transient Cycle Comparison Table 6-4: Bottom Mounted Nozzle Dimensions Table 6-5: Material Properties Table 6-6: Dimensions Comparison BMI Nozzles 48, 30 and 35 Table 6-7: Dimensions Comparison Callaway Nozzle 57 and Plant A Nozzle 58

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 List of Figures Figure 1-1: BMI Nozzle Repair Figure 6-1: Finite Element Model Mesh for Limit Load Figure 6-2: Equivalent Stresses at the Final Load Step (psi)

framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57

1.0 INTRODUCTION

During the Spring 2025 outage (R27) at Callaway Unit 1, the Reactor Vessel Bottom Head (RVBH) Bottom Mounted Instrumentation (BMI) Nozzle No. 48 is being repaired due to reactor coolant leakage at the interface between the RVBH and BMI nozzle. Additionally, indications were found in the J-groove welds at the BMI Nozzle No. 30, 35, and 57 locations. Per Reference [1], a portion of the existing BMI nozzle is removed, and an Alloy 52M weld pad is then deposited on the outer surface of the RVBH around the penetration using the ambient temperature machine gas tungsten arc welding (GTAW) temper bead process. An Alloy 690 replacement nozzle is then inserted into the penetration and welded to the weld pad and thimble guide tube using Alloy 52M filler metal. The general modified configuration is shown in Figure 1-1.

SSSA SUS DE SW EXISTING BMI NOZZLE ALLOY 600

&ggB gyZ

%yZ Zz gyg Z

ZB Ze Ai ZZ gyy ZZ Z

%Z SEN SS

§ SSM SSeS RVBE SA-633, GRADE 8, CLASS WELD ALLOY S2462MSS J-GROOVE WELD ALLOY 52M REPLACEMENT NOZZLE ALLOY 690 Ross ESS FILLET WELD~

ALLOY 62M 3,

SST THIMBLE GUIDE TUBE SA-213 TYPE 304 33 Figure 1-1: BMI Nozzle Repair

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 2.0 PURPOSE AND SCOPE The purpose of this evaluation is to perform a fracture mechanics one cycle justification (OCJ) to assess the suitability of leaving the original, as-left J-groove weld (ALJGW) at nozzle No. 48 in the RVBH, as required by Section 6.5 of Reference [1] for the half-nozzle repair detailed in Reference [2]. Since the half-nozzle repair is similar to a previously performed BMI nozzle repair at another plant (Plant A),

a comparative OCJ assessment is considered herein. Therefore, the ALJGW flaw evaluation performed for BMI nozzle No. 58 at Plant A in Reference [3] is used as the basis to demonstrate that the ALJGW flaw in the Callaway Unit 1 BMI nozzle No. 48 is acceptable for one fuel cycle beyond the modification in 2025.

The basis for the ALIJGW flaw evaluation is as follows: Since the original J-groove weld is not removed and any flaw in the J-groove weld cannot be sized by readily available non-destructive examination (NDE) techniques, it is considered that the as-left condition of the original J-groove weld includes degraded or cracked weld material extending through the entire J-groove weld and Alloy 182 butter material. It is postulated that a small fatigue-initiated flaw forms in the low alloy steel head and combines with the Primary Water Stress Corrosion Crack (PWSCC) in the weld to form a large radial corner flaw. This flaw would propagate into the low alloy steel head by fatigue crack growth under cyclic loading conditions associated with normal, upset and test conditions. As the crack grows beyond the butter into the RVBH, subsequent crack growth is driven by fatigue crack growth (i.e.

PWSCC crack growth is not applicable in the RVBH). An ASME Section X] evaluation based on linear elastic fracture mechanics (LEFM) analysis is performed to demonstrate the ALJGW flaw is acceptable for flaw growth during the applicable operating period. For the current OCJ, the assessment is done from the time of repair, for one operating cycle beyond the repair, or 18 months (1.5 years).

In addition, a limit load analysis is done to satisfy IWB-3610(d)(2), which demonstrates the primary stress limits of NB-3000 are met, assuming a local area reduction of the pressure-retaining membrane that is equal to the area of the projected flaw. Since this analysis is not included in the existing ALJGW flaw evaluation in Reference [3],

it provides necessary validation for the repair and continued operation of the RVBH.

Rev. 001: Add the modification of Nozzles 30 and 35 to the scope and justify the evaluation of Nozzle 48 documented in Rev. 000 is also applicable to the modification of Nozzles 30 and 35.

Rev. 002: Add the modification of Nozzle 57 to the scope and justify the evaluation of Nozzle 48 documented in Rev. 000 is also applicable to the modification of Nozzle 57 in addition to Nozzles 30 and 35.

Rev. 003: Update markups for proprietary information to line up with the Relief Request submitted to NRC.

Rev. 004: Update markups for proprietary information to incorporate NRC comments.

3.0 ANALYTICAL METHODOLOGY Given the as-found condition of the Callaway BMI nozzle No. 48 modification, there is insufficient time to complete a detailed life of repair finite element analysis for the ALJGW flaw during this refueling outage.

Therefore, the life of repair ALJGW flaw analysis performed in 2003 for Plant A BMI nozzle No. 58, documented in Reference [3], is used as the basis to demonstrate that the flaw is acceptable from the time of modification in 2025 for one cycle beyond the repair. In addition to the analysis methodology below for Callaway BMI nozzle No. 48, additional justification is provided for applicability to nozzles Nos. 30, 35 and 57.

The OCJ flaw evaluation is performed for one cycle of operation in accordance with Article ]WB-3610 (LEFM method).

According to lWB-3610(d) of ASME B&PV Code Section XI (Reference [4]), a component containing a flaw is acceptable for continued service during the evaluation period if the following criteria are satisfied:

1)

The criteria of IWB-3611 or !WB-3612 (Reference [4]),

Page 8

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 The primary stress limits ofNB-3000 (Reference [5]), assuming a local area reduction of the pressure-retaining membrane that is equal to the area of the projected flaw(s) as determined by the flaw characterization rules of IWA-3000.

3.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612)

Per Article lWB-3612, a flaw exceeding the limits of IWB-3500 is acceptable for continued service if the applied stress intensity factor is less than the material fracture toughness considering the following safety factors:

e 10 for normal conditions e

2 for emergency/faulted conditions, and conditions where pressure is less than 20% of the Design Pressure To demonstrate by LEFM analysis that the Callaway BMI nozzle No. 48 repair is acceptable for one cycle of operation following the repair in 2025; geometry, material, transient loading conditions, cycles, initial flaw size, applicable code year, etc. for Plant A documented in Reference [3] are compared to the Callaway Unit l repair to demonstrate that Plant A analysis is equivalent or bounding. Therefore, it can be concluded that the Callaway BMI nozzle No. 48 repair is acceptable by LEFM analysis for one cycle.

3.2 Primary Stress Limits (NB-3000)

Per [WB-3610(d)(2), the primary stress limits of NB-3000 (Reference [5]), assuming a local area reduction of the pressure retaining membrane that is equal to the area of the flaw, shall be satisfied. This criterion is not considered in the existing analysis developed for Plant A in Reference [3]. Therefore, to evaluate the requirement, article NB-3228.1 of Section HI of the ASME Code is utilized. NB-3228.1 states that the limits on General Membrane Stress Intensity (NB-3221.1), Local Membrane Stress Intensity (NB-3221.2), and Primary Membrane plus Primary Bending Stress Intensity (NB-3221.3) need not be satisfied at a specific location if it can be shown by limit analysis that the specified loadings do not exceed two-thirds of the lower bound collapse load. The yield strength of the material to be used in these calculations is 1.5S,,. Per NB-3112.1(a), the Design Pressure shall be used in showing compliance with this criterion.

4.0 ASSUMPTIONS 4.1 Unverified Assumptions There are no unverified assumptions used in this analysis.

4.2 Justified Assumptions The following justified assumptions are used in the analysis.

1)

[

2)

[

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 3)

The analysis conservatively postulates that a flaw extends through the entire J-groove weld and butter.

Operating experience demonstrates that under normal reactor operation, there are no cases of RV damage that indicate susceptibility of the low alloy steel base material to PWSCC. However, the fracture mechanics analysis conservatively assumes that the postulated flaw in the original J-groove weld will propagate through the full depth of the ALJGW and butter into the low alloy steel base material. Detailed material degradation mechanisms (and related references) can be found in Reference [6].

al 5)

[

4.3 Modeling Simplifications There are no modeling simplifications used in this analysis.

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 5.0 COMPUTER USAGE

§.1 Software This calculation uses the following software:

¢ Controlled installation of software ANSYS Mechanical Enterprise 19.2 (Reference [7]), installed and currently maintained as a controlled container at /opt/shared/containers/rhel72_ansys192.sif on the approved platform Lynchburg HPCv2, Reference [8].

o ANSYS verification tests documented in Reference [9] demonstrate that ANSYS Version 19.2 meets the requirements to be used on the HPC as a controlled-access code. Note that Version 19.2 is not the most recent approved version of ANSYS listed on EASI (Engineering Applications Software Index). However, the use of this version of ANSYS is acceptable since all error notices up to date have been reviewed and it is concluded that none of the errors may create erroneous results for the intent of this calculation.

o The container image file rhel72_ansys192.sif has been verified using the public key provided in Reference [9].

o Operating System: Red Hat Enterprise Linux release 8.2; Kernel: 4.18.0-193.e18.x86_64 The software is being used within its specified range of applicability as defined by validation and verification requirements defined in References [8] and [9].

5.2 Computer Files The computer files for runs performed in revision 000 are listed in Table 5-1. [

]

Table 5-1: Computer Files

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 6.0 CALCULATIONS 6.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612)

The LEFM analysis documented in Reference [3] for Plant A is equivalent or bounding of the current BMI nozzle No. 48 repair for Callaway Unit l as technically justified in Sections 6.1.1 through 6.1.7.

6.1.1 Key Dimension Comparison Key dimensions between the RVBH BMI nozzles for Callaway Unit 1 and Plant A are compared in Table 6-1.

==

Conclusion:==

In terms of geometry, Plant A penetration No. 58 bounds Callaway Unit 1 penetration No. 48.

Table 6-1: Key Dimensions Comparison

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 6.1.2 Material and Property Comparison The pertinent materials and properties for the RVBH BMI nozzles for Callaway and Plant A are compared in Table 6-2. [

==

Conclusion:==

In terms of material, Plant A bounds Callaway Unit 1.

Table 6-2: Material Comparison 6.1.3 Initial Flaw Size and Weld Residual Stress Comparison

==

Conclusion:==

In terms of initial flaw size and considering comparable conditions for both Plant A and Callaway Unit 1, they are considered equivalent.

6.1.4 Roll Expansion Evaluation For Plant A, possible roll expansion of the original nozzle to eliminate leakage is evaluated in Reference [14]. For the Callaway Unit 1 repair, roll expansion is also specified as an optional step in Reference [2].

==

Conclusion:==

[t is considered appropriate for this OCJ to perform the comparative evaluation using the analysis provided in Reference [3], which does not include roll expansion.

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 6.1.5 Operational Transient Condition Comparison The operational stresses and transient cycles evaluated in Reference [3] for Plant A are compared to the applicable conditions for Callaway Unit 1.

r l

I

==

Conclusion:==

In terms of operational transient conditions, Plant A bounds Callaway Unit l given the significant number of years Plant A is evaluated for, compared to one cycle for Callaway Unit 1.

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycie Justification for Nozzies 48, 30, 35 and 57 Table 6-3: Transient Cycle Comparison Page 15

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 6.1.6 General Corrosion and Fatigue Crack Growth Comparison

==

Conclusion:==

Considering general corrosion and fatigue crack growth, Plant A bounds Callaway Unit 1.

6.1.7 ASME Section XI Code Edition Comparison

==

Conclusion:==

In terms of ASME Section XI code year, Plant A bounds Callaway Unit 1 6.2 Primary Stress Limit Evaluation (ASME B&PV Code Section III NB-3000)

The acceptance criteria of Section 3.1(c) of Code Case N-749 and Article IWB-3610(d)(2) require that the primary stress limits of Article NB-3000 (Reference [5]) are met assuming a local area reduction of the pressure retaining membrane that is equal to the area of the flaw. To evaluate the requirement, Article NB-3228.1 of Section II of the ASME B&PV Code (Reference [5]) is utilized.

Article NB-3228.1 states that the limits on General Membrane Stress Intensity (NB-3221.1), Local Membrane Stress Intensity (NB-3221.2), and Primary Membrane plus Primary Bending Stress Intensity (NB-3221.3) need not be satisfied at a specific location if it can be shown by limit analysis that the specified loadings do not exceed two-thirds of the lower bound collapse load. The yield strength to be used in these calculations is 1.5S,. Per Article NB-3112.1(a), the design pressure shall be used in showing compliance with this limit.

This condition is equivalent to showing that the structure does not collapse at a pressure equal to 1.5 times the design pressure al

]

Reference [17] ). In terms of finite element (FE) method results, plastic collapse of the structure is equivalent to [

]

To demonstrate this by the FE method, cladding, Alloy 182 J-groove weld, buttering material, and portions of the RVBH wall are removed in the FE model to represent the material removed by the postulated J-Groove flaws and the crack growth. The removed material represents a conservative final flaw width and depth of [

]

which bounds the final fatigue plus corrosion flaw size after 1.5 years of crack growth as calculated in Section 6.1.6.

Controlled Documert Document No. 32-9392644-003 framatome Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 The purpose of the limit load analysis is to address the primary stress criteria of NB-3000 with respect to the volume of material removed. Explicit calculation of Stress Intensity Factors (SIF) due to the flaws shape are performed in the LEFM assessment as discussed in Section 6.1 using the criteria from IWB-3612 (Reference [4]).

For the purpose of the primary stress criteria, the volume removed in the FE model is bounding and conservative.

[

]

The FE mesh utilized is shown in Figure 6-1.

Figure 6-1: Finite Element Model Mesh for Limit Load The detailed dimensions of the lower instrument nozzle modeled are obtained from References [2] and [18]. Key dimensions are listed in Table 6-4.

Controlled Document framatome l

l Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 Table 6-4: Bottom Mounted Nozzle Dimensions S

Description i

l Value Reference(s)

RV bottom head base metal inside radius (IR)

Tt

pp

RV bottom head base metal thickness (minimum) l Original nozzle bore ID Repair weld pad thickness

)

Replacement nozzle ID Replacement nozzle bore ID Replacement nozzle OD we ee nee SOY nen meee ee Penetration horizonal distance to RVBH center J

l

[22] (outermost nozzle)

Note:

(1) For nozzle #48, the counterbore diameter extending from the OD of the head approximately [

]

(2) Bore ID; showing dimension used in FE model, replacement nozzle OD is determined in field.

3)[

The material properties are listed in Table 6-5, which are considered at a temperature of 700°F, which bounds the design temperature of 650°F (Reference [17]). The materials are considered as elastic-perfectly plastic. The value ofyield strength used is based on S,, and is defined as S, = 1.5S,,.

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 71RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 Table 6-5: Material Properties RV Bottom Head: SA-533 Grade B Class 1 (C-Mn-Mo 0.4-0.7Ni)

Temperature (°F) a (1/°F)

E (psi) l v(-)

Sm (ksi) l Sy (ksi)

_ 700 7.44E-06 2.66E+07 0.3 26.7 40.05 l

Replacement Nozzle, Weld Pad, and New J-groove Weld: Alloy 690/Alloy 52M)

Temperature (°F) a(leF) l Eq(psi) vé)

l Smeksi) l Sy (ksi) 7000 8.3E-06 l

2.75E+07 0.31:

23.3 34.95 Note(s):

1.

Material properties for RV bottom head per Reference [19].

2.

Material properties for the replacement nozzle, weld pad, and new J-groove weld per Reference

[20].

3.

S,=1.5Sn.

]

The analysis was run up to a pressure of [

] psia which is [

] which is about [

]

times the design pressure, exceeding the requirement of 1.5 times the design pressure. The equivalent stress at the last converged load step is shown in Figure 6-2.

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 Figure 6-2: Equivalent Stresses at the Final Load Step (psi) 6.3 OCJ Extended to Nozzles 30 and 35 In addition to Nozzle 48, the same half-nozzle repair modification is to be performed for BMI Nozzles 30 and 35 per Reference [1]. Rev. 000 of the report addresses only the modification of BMI Nozzle 48. Justification is provided in this section that the analysis in Rev. 000 is also applicable to the modification of BMI Nozzles 30 and

35. A major dimension comparison between these nozzles is listed in Table 6-6; values are taken from the main body of References [11] and [13] as well as from References [21] and [22].

Page 20

Controlled Document

, framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 Table 6-6: Dimensions Comparison BMI Nozzles 48, 30 and 35

==

Conclusion:==

Evaluation of the BMI Nozzle 48 presented in Sections 6.1 and 6.2 is also applicable to the modification of BMI Nozzles 30 and 35.

Controlled Document Document No. 32-9392644-003 framatome Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 6.4 OCJ Extended to Nozzle 57 In addition to Nozzles 48, 30 and 35, the same half-nozzle repair is to be performed for BMI Nozzle 57 per Reference [1] with modification detailed in Reference [21]. Rev. 000 of the report addresses only the modification of BMI Nozzle 48. Justification is provided in this section that the analysis in Rev. 000 is also applicable to the modification of BMI Nozzle 57.

A major dimension comparison between the BMI Nozzle 57 at Callaway and the BMI Nozzle 58 at Plant A is listed in Table 6-7, where values for Nozzle 58 are replicated from Table 6-1 and values for Nozzle 57 are taken from References [11] and [13].

Table 6-7: Dimensions Comparison Callaway Nozzle 57 and Plant A Nozzle 58

==

Conclusion:==

For the acceptance criteria Article [WB-3612 of Section XI, the conclusion in Section 6.1 that BMI Nozzle 48 is equivalent or bounding to BMI Nozzle 58 at Plant A, is also applicable to Callaway BMI Nozzle 57.

In addition, the evaluation presented in Section 6.2 is also applicable for BMI Nozzle 57.

Page 22

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57 7.0

SUMMARY

OF RESULTS The comparative evaluation of fatigue crack growth of the ALJGW flaw into the low alloy steel RVBH demonstrates compliance with the ASME B&PV Code,Section XI, Article IWB-3612 requirements. Therefore, the component containing the flaw is acceptable for continued service for one fuel cycle (18 months) beyond the modification in 2025.

Additionally, to satisfy the requirements of Article IWB-3610(d)(2), the primary stress limits specified in Article NB-3000 of ASME B&PV Code, Section HI are met through limit load analysis. This analysis considers a local area reduction of the pressure-retaining membrane that is equal to the area of the project flaw, considering flaw growth for one cycle.

Rev. 001: Results and conclusion are applicable to the modification of BMI Nozzles 48, 30 and 35.

Rev. 002: Results and conclusion are applicable to the modification of BMI Nozzles 48, 30, 35 and 57.

Rev. 003: Results and conclusion presented in Rev. 002 remain unchanged.

Rev. 004: Results and conclusion presented in Rev. 002 remain unchanged.

Page 23

Controlled Document framatome Document No. 32-9392644-003 Callaway Unit 1 RVBH BMI Nozzle As-Left J-Groove Weld One Cycle Justification for Nozzles 48, 30, 35 and 57

8.0 REFERENCES

Framatome Document [

]

Framatome Drawing [

]

Framatome Document [

]

ASME Boiler and Pressure Vessel Code Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, 2019 Edition.

ASME Boiler and Pressure Vessel Code Section III, Rules for Construction of Nuclear Facility Components, Division 1, Subsection NB, 2015 Edition.

Framatome Document 51-9392522-004, Corrosion Evaluation for Callaway Reactor Vessel Bottom Mounted Instrument Nozzle Repair.

ANSYS Finite Element Computer Code, Version 19.2, ANSYS Inc., Canonsburg, PA.

Framatome Document 2A4.31-2A4-ANSYS_

Mechanical _APDL-19.2_SRA-000, ANSYS Mechanical APDL Software Release Authorization.

Framatome Document 32-9298958-001, Installation Testing for ANSYS Mechanical Enterprise 19.0 and 19.2.

Framatome Document [

Framatome Document 38-939269 1-001, Transmittal of Callaway Design Input for RV BMI Nozzle Modification, Drawing E-11173-171-005, Rev 00, General Arrangement Plan.

Framatome Document 38-939269 1-001, Transmittal of Callaway Design Input for RV BMI Nozzle Modification, CENC 1303 A-498 to 528.

Framatome Document 38-2201993-000, Transmittal of WEC IP to Framatome for BMN Repair, List of Reactor Vessel Data (Supplied by Westinghouse).

Framatome Document [

Framatome Document 38-2201993-000, Transmittal of WEC IP to Framatome for BMN Repair,.

Framatome Document [

Framatome Document 38-939269 1-001, Transmittal of Callaway Design Input for RV BMI Nozzle Modification, Letter NEMU20250008 Rev.

1 May 15, 2025.

Framatome Drawing [

ASME Boiler and Pressure Vessel Code,Section III, Nuclear Power Plant Components, Division 1, 1971 Edition including Addenda through Winter 1973.

ASME Boiler and Pressure Vessel Code,Section II, Part D Properties (Customary) Materials, 2015 Edition, no Addenda.

Framatome Drawing [

Framatome Document 38-2201994-000, Transmittal of WEC IP to Framatome for BMN Repair.