ML23325A161
| ML23325A161 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 10/26/2023 |
| From: | Framatome |
| To: | Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML23325A159 | List: |
| References | |
| 102-08704-CDH/MSC 32-9370429-000 | |
| Download: ML23325A161 (1) | |
Text
Enclosure 1 Non-Proprietary Supplemental Information Relief Request 70 Proposed Alternatives in Accordance with 10 CFR 50.55a(z)(1) for Pressurizer Lower Shell Temperature Nozzle
- Document No. 32-9370730-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification
- Document No. 32-9370731-000, Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis
- Document No. 32-9370732-000, PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification
- Document No. 51-9370657-000, Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification
- Document No. 51-9370728-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Document No. 32-9370730-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification
Page 1 of 24 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY CALCULATION
SUMMARY
SHEET (CSS)
Document No.
32 9370730 000 Safety Related: Yes No Title Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification PURPOSE AND
SUMMARY
OF RESULTS:
PURPOSE:
The purpose of this calculation is to demonstrate compliance of requirements of Reference [2] and qualification of applicable ASME Code criteria, Reference [3], of the designed pressurizer temperature nozzle repair for one cycle operation. Note that a subsequent analysis will demonstrate acceptability of the replaced nozzle for operation beyond one cycle.
RESULTS:
The temperature nozzle replacement at Palo Verde Unit 1 satisfies the applicable ASME code requirements for one operating cycle for the design loading conditions identified in the Design Specification, Reference [2]. Please see summary of the results in Section 7.0.
FRAMATOME INC. PROPRIETARY This document and any information contained herein is the property of Framatome Inc. (Framatome) and is to be considered proprietary and may not be reproduced or copied in whole or in part. This document shall not be furnished to others without the express written consent of Framatome and is not to be used in any way which is or may be detrimental to Framatome. This document and any copies that may have been made must be returned to Framatome upon request.
If the computer software used herein is not the latest version per the EASI list, AP 0402-01 requires that justification be provided.
THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE VERIFIED PRIOR TO USE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:
CODE/VERSION/REV CODE/VERSION/REV Yes No Controlled Document
Document No. 32-9370730-000 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 2 Review Method: Design Review (Detailed Check)
Alternate Calculation Does this document establish design or technical requirements? YES NO Does this document contain Customer Required Format? YES NO Signature Block Name and Title (printed or typed)
Signature P/R/A/M and LP/LR Date Pages/Sections Prepared/Reviewed/Approved Brady Cameron Engineer II LP Tomas Straka Advisory Engineer M
Don Kim Advisory Engineer LR David Skulina Engineering Supervisor A
Notes:
P/R/A designates Preparer (P), Reviewer (R), Approver (A);
LP/LR designates Lead Preparer (LP), Lead Reviewer (LR);
M designates Mentor (M)
In preparing, reviewing and approving revisions, the lead preparer/reviewer/approver shall use All or All except
___ in the pages/sections reviewed/approved. All or All except ___ means that the changes and the effect of the changes on the entire document have been prepared/reviewed/approved. It does not mean that the lead preparer/reviewer/approver has prepared/reviewed/approved all the pages of the document.
With Approver permission, calculations may be revised without using the latest CSS form. This deviation is permitted when expediency and/or cost are a factor. Approver shall add a comment in the right-most column that acknowledges and justifies this deviation.
Project Manager Approval of Customer References and/or Customer Formatting (N/A if not applicable)
Name (printed or typed)
Title (printed or typed)
Signature Date Comments N/A N/A N/A N/A N/A CAMERO N Brady Digitally signed by CAMERON Brady Date: 2023.10.26 22:44:29 -04'00' STRAKA Tomas Digitally signed by STRAKA Tomas Date: 2023.10.26 22:48:46 -04'00' KIM Dong Digitally signed by KIM Dong Date: 2023.10.26 22:51:55 -04'00' SKULIN A David Digitally signed by SKULINA David Date: 2023.10.26 22:56:12 -04'00' Controlled Document
Document No. 32-9370730-000 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 3 Professional Engineer Certification Controlled Document
Document No. 32-9370730-000 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 4 Record of Revision Revision No.
Pages/Sections/Paragraphs Changed Brief Description / Change Authorization 000 All Initial Release. The Proprietary version of this document is 32-9370429-000.
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 5 Table of Contents Page SIGNATURE BLOCK............................................................................................................................. 2 PROFESSIONAL ENGINEER CERTIFICATION................................................................................... 3 RECORD OF REVISION....................................................................................................................... 4 LIST OF TABLES.................................................................................................................................. 6 LIST OF FIGURES................................................................................................................................ 6
1.0 INTRODUCTION
........................................................................................................................ 7 2.0 PURPOSE AND SCOPE............................................................................................................ 7 3.0 ANALYTICAL METHODOLOGY................................................................................................. 7 4.0 ASSUMPTIONS......................................................................................................................... 7 4.1 Unverified Assumptions.....................................................................................................................7 4.2 Justified Assumption.........................................................................................................................8 5.0 CALCULATIONS........................................................................................................................ 8 5.1 Primary Stress Evaluation.................................................................................................................8 5.1.1 Loading...............................................................................................................................8 5.1.2 Primary Stress Calc............................................................................................................8 5.2 Interference Check..........................................................................................................................15 5.3 Fatigue Assessment........................................................................................................................16 5.4 Corrosion Evaluation.......................................................................................................................17 6.0 COMPUTER USAGE............................................................................................................... 17
7.0 CONCLUSION
......................................................................................................................... 17
8.0 REFERENCES
......................................................................................................................... 19 APPENDIX A : CONTINGENCY OVERBORE.................................................................................... 20 Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 6 List of Tables Page Table 7-1: Summary Table.................................................................................................................. 18 List of Figures Page Figure 5-1: Fillet Weld Dimensions....................................................................................................... 9 Figure 5-2: Weld Shear Stress Line.................................................................................................... 11 Figure 5-3: Counterbore Dimensions.................................................................................................. 13 Figure 5-4: Pressurizer Drawing Excerpt [12]...................................................................................... 15 Figure A-1: Fillet Weld Dimensions..................................................................................................... 21 Figure A-2: Weld Shear Stress Line.................................................................................................... 22 Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 7
1.0 INTRODUCTION
Recent inspection of the pressurizer at Palo Verde Unit 1 nuclear power station revealed leakage from one of its instrumentation nozzles. The nozzle identified is the lower temperature nozzle located on the pressurizer shell. A nozzle replacement is being performed to repair the affected area. The proposed design is nearly identical to that performed in 1992 except that the sleeve is being shortened such that it does not get welded by the outside weld pad and that the filler metal used is Alloy 52M. The 1992 repair is documented in 32-1212318-002, Reference [1].
2.0 PURPOSE AND SCOPE The purpose of this calculation is to demonstrate compliance of requirements of the Design Specification, Reference [2], and the qualification of applicable ASME Code criteria, Reference [3], of the designed pressurizer temperature nozzle repair for one cycle operation. Note that a subsequent analysis will demonstrate acceptability of the replaced nozzle for operation beyond one cycle. For information, code reconciliation is performed in 51-9370647.
The scope of this calculation is quantitative qualification of primary stresses requirements and qualitative qualification of primary plus secondary stresses and fatigue requirements. Per Reference [2], this analysis includes the modifications (new weld pad, new J-groove weld, replacement nozzle) up to the end of the nozzle but excluding the thermowell weld. The thermowell to nozzle weld was evaluated in Reference [4] and was found to be acceptable.
3.0 ANALYTICAL METHODOLOGY The following process is applied for demonstration of compliance with applicable ASME code requirements, Reference [3]. Primary stresses requirements are qualified for the life of the repair. Primary plus secondary stresses and fatigue is qualified for one cycle of operation.
Compliance with primary stress requirements:
- 1) Calculation of tentative nozzle thickness and comparison with designed thickness. This approach is applicable as there are no appreciable external or inertia nozzle loads.
- 2) Calculation of shear stress in the repair weld connecting the nozzle to the weld pad due to pressure load considering corrosion effect on low alloy steel. Calculated stress is compared to allowable limits of design condition and applicable limits of operating conditions.
- 3) Comparison of weld design sizes with minimum code size requirements as well as comparison of deigned nozzle clearances with code clearances requirements.
- 4) Assessment of repair and corrosion impact on reinforcements of opening code requirements using guidance of paragraph NB-3332.
- 5) Primary plus secondary stresses and fatigue are qualified for one cycle operation using qualitative approach of comparison of the original repair with the designed repair.
4.0 ASSUMPTIONS 4.1 Unverified Assumptions Reference [9] contains the following unverified assumption:
- 1) It is assumed the proportions of time that Palo Verde Unit 1 will be in the operating, shutdown, and startup conditions during the operating cycle for which this document applies (i.e., operating cycle 25) will be the same as those indicated by historical operation data (Palo Verde Generating Station Document 13-MS-B041, in Reference [8]).
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 8
- 2) Palo Verde Unit 1 will maintain RCS primary water chemistry in accordance with the EPRI PWR Primary Water Chemistry Guidelines during the operating cycle for which this document applies (i.e.,
operating cycle 25).
4.2 Justified Assumption Corrosion is assumed to occur [
]
[
] Furthermore, that the original repair lasted 31 years. The new nozzle and its weld connection is stronger and therefore suitable for one cycle operation.
[
]
5.0 CALCULATIONS 5.1 Primary Stress Evaluation The purpose of this section is to verify the primary stress requirements for the design shown in Reference [5]. The replacement nozzle is shown in Reference [6]. The verification is based on the requirements of Reference [3] and as specified in Reference [2]. More specifically the following are included in the one cycle justification:
- 1) Partial penetration J-groove weld (Alloy 52M)
- 2) New nozzle (Alloy 690)
- 3) New weld pad (Alloy 52M)
- 4) Stresses in the vicinity of the opening (low alloy steel) satisfied by reinforcement requirements.
5.1.1 Loading Pressure loads are the only substantial loads, for evaluation of primary stresses, explicitly performed in this calculation on the nozzle. Note, that a subsequent analysis will examine thermal loads for operation beyond one cycle.
5.1.2 Primary Stress Calc There are no substantial external piping loads on the nozzle. Shear stress due to internal pressure is considered on the nozzle weld. Primary stresses are also considered for the nozzle and are satisfied with the tentative pressure nozzle thickness calculation.
5.1.2.1 New J-Groove Weld Weld Size (NB-3352.4, Reference [3])
This weld needs to satisfy the minimum dimension requirements of Figure NB-4244(d)-1(e) and Section NB-3352.4(d)(2).
The nozzle external dimensions will not be known until field drilling of the weld pad counterbore. However, the wall thickness can be determined based on the nominal counterbore ID and the nominal nozzle clearance (Reference [7]). Therefore, the expected nominal nozzle wall thickness is:
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 9
=
((_ - )_)
=
Reference [5], [7]
The J-groove weld depth and fillet leg shall be no less than
= [
] The actual values are [
] This requirement is satisfied.
The weld length along the nozzle OD shall be no less than 1.5 = [
] The actual value is [
] This requirement is satisfied.
The minimum required weld throat thickness (tc) is the lowest values between 0.7tn and 0.25. =
[
] The minimum actual value of tc is calculated to be:
= sin tan
=
The minimum fillet weld dimensions, taken from Reference [5], are shown in Figure 5-1. This requirement is satisfied.
Figure 5-1: Fillet Weld Dimensions The gap between the outer sleeve remnant and the step in the nozzle OD, as depicted on Figure NB-4244(d)-
1(e), Reference [3], shall be in the range of 1/16 and tn [
] The gap is assured by the calculation of Dim. Y (Reference [6]) in Sequence C10-00 in the traveler (Reference [7]). Based on worst case as-built dimensions, the minimum gap was calculated to be [
] This requirement is satisfied.
The code minimum size of the r2 radius requirement is 1/16. Reference [5] indicates [
] min radius. The requirement is thus satisfied.
Nozzle Diametric Clearance (NB-3337.3(a), Reference [3])
For a nozzle OD between 1 and 4, the maximum diametric clearance of 0.020 per NB-3337.3(a) is satisfied, according to Appendix C in Reference [7].
leg2= [
]
tc leg1 = [
]
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 10 5.1.2.2 Weld Shear Stress Weld Shear Stress (NB-3227.2, Reference [3])
The weld shear stress line is conservatively taken as the minimum J-groove weld depth, shown in Figure 5-2 in red. The shear stress is calculated below:
The calculated shear force is:
= [D + tol + 2(grind) + 2(corr)(years )]
4
=
Where:
P is the design pressure of 2500 psi, Reference [8].
tol is the weld pad counterbore tolerance of 0.017 in, Reference [5].
[
]
D is design diameter of the weld pad counterbore of [
] Reference [5].
corrrate is the corrosion rate of [
] Reference [9].
years is the longest possible duration of corrosion [
]
The shear stress is:
=
=
Where:
P is the design pressure of 2500 psi, Reference [8].
lv is the shear line, shown in red in Figure 5-2, which is conservatively chosen to be the J-groove weld depth of [
] Reference [5].
dnozzle is the nozzle diameter taken as the nominal weld pad ID_cb - clearance = [
] Reference [5].
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 11 Figure 5-2: Weld Shear Stress Line The weld material is listed as Alloy 52M in Reference [2]. Sm is the design stress intensity of 23300 psi (Reference [10]) at design temp 700°F (Reference [8]) for Alloy 690, which is equivalent to Alloy 52M. The allowable shear per NB-3227.2 is 0.6 = 0.6(23300) = 13980, which is greater than [
]
5.1.2.3 Nozzle Pressure Wall Thickness Tentative Nozzle Pressure Thickness (NB-3324.1, Reference [3])
The tentative nozzle thickness is:
=
0.5= 2500 23300 0.5(2500) =
Where:
P is the design pressure of 2500 psi, Reference [8].
r is the nozzle inside radius of [
] Reference [6].
Sm is the design stress intensity of 23300 psi at design temp 700°F for Alloy 690, Reference [10].
Nozzle thickness at the pressure boundary:
_= () (+ )
2
=
Where:
IDcb is the nominal weld pad counterbore of [
] in, Reference [5].
tol1 is the weld pad counterbore tolerance of [
] in, Reference [5].
tol2 is the nozzle tolerance of [
] in, Reference [6].
clearance is the assumed final machining clearance of the nozzle OD of [
] in, Reference
[7].
d is the nozzle inside diameter of [
] in, Reference [6].
Nozzle Weld Pad
[
]
[
]
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 12 The minimum nozzle thickness is significantly larger than the calculated tentative nozzle thickness. Since pressure load is the only considerable load imposed on the nozzle, the primary stress criteria for the replacement nozzle are satisfied.
5.1.2.4 Evaluation of Nozzle Counterbore Nonconformity Per Reference [11], the nozzle counterbore, Figure 5-3, after final machining is out of tolerance. Stress intensity due to pressure is calculated and compared to primary general membrane stress criteria of 1.0*Sm = 23300 psi, paragraph NB-3221.1, Reference [3]. The design stress intensity is taken from Reference [10] at design temperature of 700°F. The counterbore diameter per Reference [11] is [
] inches. The outside diameter of the nozzle at the place of the counterbore is [
] inches per Reference [6].
a)
Calculation of hoop stress:
=
= 2500
=
b) Calculation of axial stress:
=
=
4
4 (
)
4= 2500
=
c)
Determination of radial stress:
The radial stress is conservatively considered as compressive design pressure of the coolant.
= = 2500 d) Determination of Stress Intensity:
The calculated Stress Intensity is below the general primary membrane stress intensity limit of 23300 psi.
Where:
hoop is the calculated hoop stress due to internal pressure, psi.
axial is calculated axial stress due to internal pressure, psi.
rad is calculated radial stress due to internal pressure, psi.
A is calculated area exposed to internal pressure, in2.
F is calculated load due to internal pressure, lb.
SI is calculated Stress Intensity in the counterbore region, psi.
P is internal design pressure, 2500 psi, Reference [8].
di is measured counterbore diameter of [
] Reference [11].
Do is nozzle outside diameter of [
] considering tolerance, Reference [6].
t is thickness of the nozzle at the counterbore, t = (Do-di)/2 = [
]
Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 13 Figure 5-3: Counterbore Dimensions 5.1.2.5 Reinforcement Requirements for OpeningsSection III, Subsection NB, Article NB-3000, Paragraph NB-3332.1 (Reference [3]) sets requirements for openings not requiring reinforcement.
There are three regions of the penetration that may be exposed to the coolant fluid for different time periods.
- 1) Region of the original J-weld at the inside surface of the vessel. Since the weld is constructed using PWSCC susceptible material, it is conservatively assumed that corrosion started at the very beginning of the service in 1986. Corrosion of the low alloy steel behind the alloy 600 of the weld caused corrosion of the weld preparation geometry for [
] and, as such, its enlarged size is calculated.
- 2) Second region is the bore performed as part of the [
] repair that is considered to be drilled to
[
] (Reference [13]) diameter is conservatively assumed to corrode from the very beginning of the repair service as the sleeve autogenous weld is made of PWSCC susceptible material. Corrosion duration at this region behind the original sleeve is [
] Bore enlargement is calculated using
[
]
- 3) Finally, there is the new counterbore performed during this repair. This area will be subject to corrosion for the rest of the plant life of [
]
di Do Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 14 Paragraph NB-D UHTXLUHVWKDWDVLQJOHRSHQLQJKDVDGLDPHWHUQRWH[FHHGLQJ¥5WZKHUH5LVWKHPHDQ
radius of the vessel and t is the nominal vessel thickness. Per Reference [12], the mean radius of the vessel base metal is [
] 7KHUHIRUHWKHSHQHWUDWLRQERUHGLDPHWHUVKDOOQRWH[FHHG¥5W
[
] The bore diameter is [
] per Reference [13]. With a corrosion rate of
[
] the bore diameter would corrode over [
] Note, that this is greater than the counterbore of [
] which would corrode [
] by the end of the vessel life [
] and the original bore of [
]
(Reference [8]), which would corrode [
] by the end of the vessel life [
] The original J-groove weld preparation geometry drawing with detailed dimensions is not available currently. A digitizing technique was utilized to measure the maximum diameter of the preparation.
Number of drawings were digitized. [
] It is concluded that the maximum penetration dimension not requiring reinforcement is bounding the expected configuration after [
] of corrosion due to exposure to the reactor coolant.
Paragraph NB-D DOVRVHWVUHTXLUHPHQWVIRUWZRRUPRUHSHQHWUDWLRQVZLWKLQDQ\\FLUFOHRIGLDPHWHU¥5W
[
] Note that digitization of this drawing was utilized as more detailed drawing is not available currently.
Paragraph NB-3332.1 b) sets additional requirements for closely spaced penetration. As stated above, there are no additional closely spaced penetrations.
Paragraph NB-F UHTXLUHVWKDWQRXQUHLQIRUFHGRSHQLQJVKDOOKDYHLWVFHQWHUFORVHUWKDQ¥5WWRWKHHGJH
of a locally stressed area in the shell. Locally stressed area is defined within paragraph NB-3332.1 as any area in the shell where the primary local membrane stress exceeds 1.1 Sm. Exceedance of this primary stress limit would be a result of a local thinning of a shell thickness below its tentative pressure thickness. The cylindrical portion of the vessel thickness is [
] This thinnest spherical portion of the vessel is [
] as depicted in Figure 5-4. The tentative thickness of the cylinder is [
] and [
] of the spherical closure per
[
] The spherical part of the vessel is evidently significantly thicker that the minimum required thickness. [
] Furthermore, based on pages 9 and 10 of the original stress report (N001_6.04-73-1) which is contained in Reference [8], the maximum reported PL+Pb anywhere in this area is [
] for Design conditions and
[
] for Faulted (vs. 1.1Sm = 29.37 ksi) demonstrating that this is not a locally stressed area.
It is therefore concluded that the temperature nozzle penetration does not require reinforcement.
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 15 Figure 5-4: Pressurizer Drawing Excerpt [12]
5.2 Interference Check Axial Interference Between Nozzle and Remaining Sleeve Replacement nozzle material: Alloy 690 Existing sleeve material: Alloy 690 7KHWKHUPDOH[SDQVLRQFRHIILFLHQW 8.3x10-6 in/in/°F (Alloy 690 at 700°F from Reference [10])
A conservative sleeve length, with dimensions from Reference [5], is calculated as follows:
+ -
Where:
tpzr is the nominal thickness of the pressurizer at nozzle of [
] Reference [5].
tweld pad is the maximum thickness of the new weld [
] Reference
[5].
CBdepth is the minimum counterbore depth [
] Reference [5].
5.2.1.1 A conservative nozzle length (Lnozzle) is calculated as the length of the J-groove fillet weld to the end of the counterbore with dimensions taken from Reference [5].
_+
Where:
CBdepth_max is the maximum counterbore depth of [
] Reference [5].
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 16 Lfillet is the minimum length of the fillet weld along the nozzle of [
] Reference [5].
The temperature difference is 7 = [
]
The maximum length change due to thermal expansion is:
= + = (+ )
=
Where:
700°F is design condition temperature taken from Reference [8].
[
] is assumed temperature during installation, Section 4.2.
is coefficient of thermal expansion, 8.3E-6 taken from Reference [10].
The remaining gap between nozzle and remaining sleeve must be no less than 1/16 in.
5.3 Fatigue Assessment The ASME Code places a limit on secondary stresses to prevent failure by excessive distortion (thermal ratchet) caused by the repeated application of loads. The Code also limits peak stresses, through the cumulative fatigue usage factor, to prevent failure by fatigue.
The assessed repair is [
] Reference [14]
documents ASME Section III qualification of the original repair and concluded that the predicted [
]
It is reasonable to conclude that the new repair is acceptable for one operating cycle, [
]
However, the new repair weld and weld pad has similar physical material properties with the original repair weld.
The [
]
Review of the results documented in [
] Therefore, the primary plus secondary stress limits are satisfied for the new repair.
Very small usage factor is expected to be accumulated during one operating cycle [
]
It should also be noted, that while the defined insurge transients are quite severe, their effect on the new j-groove weld would not be expected to be significant as it is largely protected from thermal shocks from the bulk fluid temperature of the pressurizer. Where these transients would have their largest impact (near the ID) is not being changed by this repair. Furthermore, the design is quite similar to the [
] repair, which lasted more than
[ ] years in actual conditions.
Therefore, it is concluded that the pressurizer temperature nozzle is acceptable for one fuel cycle operation satisfying applicable ASME Section III criteria.
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 17 5.4 Corrosion Evaluation Corrosion effects have been generated in Reference [9] as surface degradation rate and are considered in the reinforcement requirements and shear force calculation. Corrosion is conservatively assumed on the base metal surfaces that are exposed to coolant fluid due to PWSCC susceptible weld material. It is conservatively assumed that ingress of coolant fluid occurred at the beginning of the service of PWSCC susceptible weld material.
Corrosion has negligible impact on the replacement nozzle and new weld pad.
6.0 COMPUTER USAGE No specific engineering software is used in this calculation.
7.0 CONCLUSION
This calculation demonstrates compliance of requirements of Reference [2] and qualification of applicable ASME Code criteria, Reference [3], of the designed pressurizer temperature nozzle repair. Primary stresses qualification is valid for the life of the repair. Qualification of primary plus secondary stresses and fatigue of the temperature nozzle repair is acceptable for one fuel cycle of operation. See the result summary table below in Table 7-1. Note that a subsequent analysis will demonstrate acceptability of the replaced nozzle for operation beyond one cycle.
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 18 Table 7-1: Summary Table Primary Stress Qualification Component/Item Appurtenance Qualification Method Result Allowable Limit Ratio PZR Vessel Cylindrical Shell, Nozzle Penetration Section 5.1.2.5 Code Guidance [
]
3.18 in
[
]
Nozzle Main body Section 5.1.2.3 Tentative thickness
[
]
0.0486 in
[
]
Counterbore Section 5.1.2.4 Stress Intensity Comparison
[
]
23300 psi [
]
Diametrical Clearance Section 5.1.2.1 Installation Procedure
[
]
0.000 in to 0.020 in
[
]
$[LDOJDS
Section 5.1.2.1 Installation Procedure
[
]
1/16 in to 0.2875 in
[
]
R2 Radius Section 5.1.2.1 Dimensional Comparison
[
]
1/16 in min
[
]
Nozzle Connecting Weld Throat size Section 5.1.2.1 Dimensional Comparison
[
]
0.2013 in
[
]
Weld depth Section 5.1.2.1 Dimensional Comparison
[
]
0.216 in
[
]
Weld leg Section 5.1.2.1 Dimensional Comparison
[
]
0.216 in
[
]
Weld Length Section 5.1.2.1 Dimensional Comparison
[
]
0.431 in
[
]
Shear Stress Section 5.1.2.2 Stress Comparison
[
]
13980 psi [
]
Primary plus Secondary Stresses and Fatigue Component/Item Appurtenance Qualification Method Result Allowable Limit Ratio Vesel, Nozzle, Connecting Weld Primary plus Secondary Stress Range, Section 5.3 Qualitative Comparative Assessment
[
]
69.9 ksi
[
]
Fatigue, Section 5.3 Qualitative Comparative Assessment
[
]
1.0
[
]
- Note that the ratio is satisfied for a value of 1 or greater.
The pressure boundary at the thermowell to nozzle weld was evaluated in Reference [4] and was found to be acceptable. A summary of results table for the thermowell weld can be found within the conclusion of Reference
[4].
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Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 19
8.0 REFERENCES
1.
Framatome Document 32-1212318-02, APS Pressurizer Instrument Nozzle Sizing Calcs.
2.
Framatome Document 08-9370351-001, Palo Verde Unit 1 Pressurizer Temperature Nozzle Modification.
3.
ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Facility Components, Division 1 - Subsection NB, Class 1 Components, 2013 Edition.
4.
Framatome Document 32-9370512-000, Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis.
5.
Framatome Drawing 02-8152574-E-001, Palo Verde Unit 1 Pressurizer Lower Shell Temperature Nozzle Repair.
6.
Framatome Drawing 02-8152712-C-002, Palo Verde Unit 1 Pressurizer Temperature Nozzle.
7.
Framatome Document 50-9370348-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement.
8.
Framatome Document 38-9370474-000, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023.
9.
Framatome Document 51-9370417-000, Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification.
10.
ASME Boiler and Pressure Vessel Code,Section II, Materials, Part D, Properties (Customary), 2013 Edition.
11.
Framatome Document CR2023-2489, Counterbore ID Measurement OOT +.002.
12.
Framatome Drawing 02-1214151-E-02, Palo Verde Nuclear Generating Station Pressurizer Nozzle Replacement.
13.
Framatome Drawing 02-1214131-E-01, Temperature Nozzle Installation.
14.
Framatome Document 32-1212270-01, APS Pressurizer Lower Temperature Nozzle Evaluation.
15.
Framatome Drawing 02-8152799-C-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Overbore Contingency.
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 20 APPENDIX A:
CONTINGENCY OVERBORE A.1 Primary Stress Evaluation The purpose of this section remains the same as that found in the main body of the document in Section 5.1 but for the contingency overbore, Reference [5], [15].
A.1.1 Loading Pressure is the only substantial load on the nozzle.
A.1.2 Primary Stress Calc There are no substantial external piping loads on the nozzle. Shear stress due to internal pressure is considered on the nozzle weld. Primary stresses are also considered for the nozzle and are satisfied with the tentative pressure nozzle thickness calculation.
A.1.2.1 New J-Groove Weld Weld Size (NB-3352.4, Reference [3])
This weld needs to satisfy the minimum dimension requirements of Figure NB-4244(d)-1(e) and Section NB-3352.4(d)(2).
The wall thickness can be determined based on the nominal counterbore ID and the nominal nozzle clearance (Reference [7]). Therefore, the expected nominal nozzle wall thickness is:
=
((_ - )_)
=
Reference [5], [7]
The J-groove weld depth and fillet leg shall be no less than
=
The actual values are [
]. This requirement is satisfied.
The weld length along the nozzle OD shall be no less than 1.5 =
The actual value is [
] This requirement is satisfied.
The minimum required weld throat thickness (tc) is the lowest values between 0.7tn DQG=
[
] The minimum actual value of tc is calculated to be:
= sintan
=
The minimum fillet weld dimensions, taken from Reference [5], are shown in Figure A-1. This requirement is satisfied.
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 21 Figure A-1: Fillet Weld Dimensions The code minimum size of the r2 radius requirement is 1/16. Reference [5] indicates [
] min radius. The requirement is thus satisfied.
Nozzle Diametric Clearance (NB-3337.3(a), Reference [3])
For a nozzle OD between 1 and 4, the maximum diametric clearance of 0.020 per NB-3337.3(a) is satisfied, according to Appendix C in Reference [7].
A.1.2.2 Weld Shear Stress Weld Shear Stress (NB-3227.2, Reference [3])
The weld shear stress line is conservatively taken as the minimum j-groove weld depth, shown in Figure A-2 in red. The shear stress is calculated below:
The calculated shear force is:
= [D + tol + 2(grind) + 2(corr)(years )]
4
=
Where:
P is the design pressure of 2500 psi, Reference [8].
tol is the is the weld pad counterbore tolerance of 0.017 in, Reference [5].
[
]
D is design diameter of the weld pad counterbore of [
] Reference [5].
corrrate is the corrosion rate of [
] Reference [9].
years is the longest possible duration of corrosion [
]
leg2= [
]
tc leg1 = [
]
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 22 The shear stress is:
=
=
Where:
P is the design pressure of 2500 psi, Reference [8].
lv is the shear line, shown in red in Figure A-2, which is conservatively chosen to be the j-groove weld depth of [
] Reference [5].
dnozzle is the nozzle diameter taken as the nominal weld pad ID_cb - clearance = [
] Reference [5].
Figure A-2: Weld Shear Stress Line The weld material is listed as Alloy 52M in Reference [2]. Sm is the design stress intensity of 23300 psi (Reference [10]) at design temp 700°F (Reference [8]) for Alloy 690, which is equivalent to Alloy 52M. The allowable shear per NB-3227.2 is 0.6 = 0.6(23300) = 13980, which is greater than [
]
A.1.2.3 Nozzle Pressure Wall Thickness Tentative Nozzle Pressure Thickness (NB-3324.1, Reference [3])
The tentative nozzle thickness is:
=
0.5= 2500 23300 0.5(2500) =
Where:
P is the design pressure of 2500 psi, Reference [8].
r is the nozzle inside radius of [
] Reference [15].
Sm is the design stress intensity of 23300 psi at design temp 700°F for Alloy 690, Reference [10].
Nozzle Weld Pad
[
]
[
]
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 23 Nozzle thickness at the pressure boundary:
_= () (+ )
2
=
Where:
IDcb is the nominal weld pad counterbore of [
] in, Reference [5].
tol1 is the weld pad counterbore tolerance of [
] in, Reference [5].
tol2 is the nozzle tolerance of [
] in, Reference [6].
clearance is the assumed final machining clearance of the nozzle OD of [
] in, Reference
[7].
d is the nozzle inside diameter of [
] in, Reference [6].
The minimum nozzle thickness is significantly larger than the calculated tentative nozzle thickness. Since pressure load is the only considerable load imposed on the nozzle, the primary stress criteria for the replacement nozzle are satisfied.
A.1.2.4 Reinforcement Requirements for Openings The contingency overbore max diameter is [
] per Reference [5]. With a corrosion rate of [
] the bore diameter would corrode over [
] to size of [
] Therefore, the reinforcement requirements found in the main body of this document (Section 5.1.2.5) remain applicable to the overbore contingency.
A.2 Interference Check Axial Interference Between Nozzle and Remaining Sleeve Replacement nozzle material: Alloy 690 Existing sleeve material: Alloy 690 7KHWKHUPDOH[SDQVLRQFRHIILFLHQW [-6 in/in/°F (Alloy 690 at 700°F from Reference [10])
A conservative sleeve length, with dimensions from Reference [5], is calculated as follows:
+ -
Where:
tpzr is the nominal thickness of the pressurizer at nozzle of [
] Reference [5].
tweld pad is the maximum thickness of the new weld [
] Reference
[5].
CBdepth is the minimum counterbore depth [
] Reference [5].
Controlled Document
Document No. 32-9370730-000 PROPRIETARY Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification Page 24 A conservative nozzle length (Lnozzle) is calculated as the length of the J-groove fillet weld to the end of the counterbore with dimensions taken from Reference [5].
_+
Where:
CBdepth_max is the maximum counterbore depth of [
] Reference [5].
Lfillet is the minimum length of the fillet weld along the nozzle of [
] Reference [5].
7KHWHPSHUDWXUHGLIIHUHQFHLV7 [
]
The maximum length change due to thermal expansion is:
= + = (+ )
=
Where:
700°F is design condition temperature taken from Reference [8].
[
] is assumed temperature at during installation, Section 4.2.
LVFRHIILFLHQWRIWKHUPDOH[SDQVLRQ(-6 taken from Reference [10].
The remaining gap between nozzle and remaining sleeve must be no less than 1/16 in.
A.3 Fatigue Assessment The assessed contingency repair is still very similar to the geometry of the standard repair found in main body of this document. Therefore, the fatigue assessment found in Section 5.3 remains applicable to the overbore contingency.
A.4 Corrosion Evaluation Corrosion effects have been evaluated in Reference [9] and are considered in the reinforcement requirements and shear force calculation. Corrosion has negligible impact on the replacement nozzle and new weld pad.
A.5 Conclusion The contingency overbore instrumentation nozzle repair satisfies the applicable ASME code requirements and is acceptable for at least one fuel cycle of operation.
Controlled Document Document No. 32-9370731-000, Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis
Page 1 of 18 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY CALCULATION
SUMMARY
SHEET (CSS)
Document No.
32 9370731 000 Safety Related: Yes No Title Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis PURPOSE AND
SUMMARY
OF RESULTS:
Purpose:
The purpose of this document is to provide the ASME Class 1 design analysis of the Palo Verde Unit 1 Pressurizer (PRZR) Thermowell to Instrument Nozzle Weld. The weld forms part of the PRZR pressure boundary and is designed in accordance with the design specification, Framatome Document 08-9370351 [1]. As required by the specification (Section 4.3.1), the design calculations consider criteria from paragraph NB-3600 of the ASME Code,Section III, 2013 Edition [2].
Results:
Section 6.0 SURYLGHVDWDEXODWLRQRIDOOUHVXOWV,WLVVKRZQWKDWWKHZHOGVL]HRILVDFFHSWDEOHWKHVWUHVVHV
are acceptable, and the cumulative usage factor is acceptable.
FRAMATOME INC. PROPRIETARY This document and any information contained herein is the property of Framatome Inc. (Framatome) and is to be considered proprietary and may not be reproduced or copied in whole or in part. This document shall not be furnished to others without the express written consent of Framatome and is not to be used in any way which is or may be detrimental to Framatome. This document and any copies that may have been made must be returned to Framatome upon request.
If the computer software used herein is not the latest version per the EASI list, AP 0402-01 requires that justification be provided.
THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE VERIFIED PRIOR TO USE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:
CODE/VERSION/REV CODE/VERSION/REV Yes No N/A Controlled Document
Document No. 32-9370731-000 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 2 Review Method: Design Review (Detailed Check)
Alternate Calculation Does this document establish design or technical requirements? YES NO Does this document contain Customer Required Format? YES NO Signature Block Name and Title (printed or typed)
Signature P/R/A/M and LP/LR Date Pages/Sections Prepared/Reviewed/Approved CJ McGaughy Advisory Engineer P
All Eric Nelson Advisory Engineer R
All Carrie Riddle Engineering Supervisor A
All Notes:
P/R/A designates Preparer (P), Reviewer (R), Approver (A);
LP/LR designates Lead Preparer (LP), Lead Reviewer (LR);
M designates Mentor (M)
In preparing, reviewing, and approving revisions, the lead preparer/reviewer/approver shall use All or All except in the pages/sections reviewed/approved. All or All except means that the changes and the effect of the changes on the entire document have been prepared/reviewed/approved. It does not mean that the lead preparer/reviewer/approver has prepared/reviewed/approved all pages of the document.
With Approver permission, calculations may be revised without using the latest CSS form. This deviation is permitted when expediency and/or cost are a factor. Approver shall add a comment in the right-most column that acknowledges and justifies this deviation.
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Document
Controlled Document
Document No. 32-9370731-000 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 4 Record of Revision Revision No.
Pages/Sections/Paragraphs Changed Brief Description / Change Authorization 000 N/A Original Issue. The Content of this document is identical to 32-9370512-000, except that proprietary information is redacted.
Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 5 Table of Contents Page SIGNATURE BLOCK............................................................................................................................. 2 PROFESSIONAL ENGINEER CERTIFICATION................................................................................... 3 RECORD OF REVISION....................................................................................................................... 4 LIST OF TABLES.................................................................................................................................. 6 LIST OF FIGURES................................................................................................................................ 6
1.0 INTRODUCTION
........................................................................................................................ 7 1.1 Purpose.............................................................................................................................................7 1.2 Results...............................................................................................................................................7 2.0 METHODOLOGY....................................................................................................................... 7 3.0 ASSUMPTIONS......................................................................................................................... 8 3.1 Assumptions Requiring Verification..................................................................................................8 3.2 Justified Assumptions........................................................................................................................8 4.0 DESIGN INPUT.......................................................................................................................... 9 4.1 Design Conditions.............................................................................................................................9 4.2 Drawings............................................................................................................................................9 4.3 Material Properties............................................................................................................................9 4.4 Applicable Loads...............................................................................................................................9 4.5 Plant Transients..............................................................................................................................12 5.0 CALCULATIONS...................................................................................................................... 12 5.1 Pressure Sizing Calculation............................................................................................................12 5.2 Stress Evaluation............................................................................................................................13 5.2.1 NB-3652............................................................................................................................13 5.2.2 NB-3653.1.........................................................................................................................14 5.2.3 NB-3653.2.........................................................................................................................15 5.2.4 NB-3653.3.........................................................................................................................15 5.2.5 NB-3653.4.........................................................................................................................16 5.2.6 NB-3656............................................................................................................................16
6.0 CONCLUSION
......................................................................................................................... 16
7.0 REFERENCES
......................................................................................................................... 18 Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 6 List of Tables Page Table 4-1: Material Properties............................................................................................................... 9 Table 4-2: Deadweight Loads............................................................................................................. 10 Table 4-3: Seismic Loads................................................................................................................... 10 Table 4-4: Plant Transient Cycles....................................................................................................... 12 Table 6-1: Summary of Results........................................................................................................... 17 List of Figures Page Figure 4-1: Thermowell and Temperature Detector Information.......................................................... 11 Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 7
1.0 INTRODUCTION
1.1 Purpose The purpose of this document is to provide the ASME Class 1 design analysis of the Palo Verde Unit 1 Pressurizer (PRZR) Thermowell to Instrument Nozzle Weld. The weld forms part of the PRZR pressure boundary and is designed in accordance with the design specification, Framatome Document 08-9370351 [1]. As required by the specification (Section 4.3.1), the design calculations consider criteria from Subarticle NB-3600 of the ASME Code,Section III, 2013 Edition [2].
1.2 Results Section 6.0 provides a tabulation of all results. It is shown that the weld size of 3/8 is acceptable, the stresses are acceptable, and the cumulative usage factor is acceptable.
2.0 METHODOLOGY As required by reference [1], Paragraph NB-3600 of the ASME Code, 2013 Edition [2] is used to evaluate the weld between the thermowell and the instrumentation nozzle shown in references [3] and [4].
Weld Sizing:
Fillet weld sizing for socket weld fittings is done by ensuring that the weld size meets the requirements of NB-4427. NB-4427 requires the weld for a socket weld fitting to have a minimum leg size of 1.09 times the nominal thickness of the pipe. [
]
Design Conditions / Faulted Conditions:
Design conditions are evaluated in accordance with NB-3652 using Eq. 9. Design pressure, deadweight, and OBE seismic loads are considered in the evaluation. Faulted conditions are evaluated in accordance with NB-3656 using Eq. 9. Design pressure, deadweight, and SSE seismic loads are considered in the evaluation.
Note that the thermowell and temperature detector deadweight and seismic self-weight loads are evaluated in Section 4.4 to demonstrate that they are bounded by the loads considered.
Level A Service Limits:
As stated in reference [6], there are no specified external loads for the temperature nozzle. This is due to the fact that there is no piping connected to this nozzle. Therefore, the thermal expansion loads listed in reference [6] do not apply. The same deadweight and seismic loads considered for design conditions are used for level A service limits as well. Level A condition stresses are calculated in accordance with NB-3653 using Eqs. 10 and 11. The full range of temperature from 70°F to 700°F (design temperature) is considered in calculating the discontinuity stresses caused by the difference in thermal expansion coefficient between Alloy 690 and stainless steel.
[
]
- 1. [
]
- 2. [
]
Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 8
- 3. [
]
Fatigue:
Cumulative usage factor is calculated assuming that the range of loading is from deadweight and OBE seismic loads. In reality, deadweight loads do not change and therefore are not required to be considered in the range of loading. The OBE loads are only required to be considered for OBE cycles. However, for conservatism and simplicity, deadweight and OBE loads are applied for each of the loading cycles considered.
Vibration:
[
]
[
]
3.0 ASSUMPTIONS 3.1 Assumptions Requiring Verification There are no assumptions requiring verification.
3.2 Justified Assumptions
- 1. [
]
- 2. [
]
[
]
Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 9 4.0 DESIGN INPUT 4.1 Design Conditions Design Temperature
= 700 F
[6] (Section 4.1, p. C-11)
Design Pressure
= 2500 psia
[6] (Section 4.1, p. C-11) 4.2 Drawings Temperature Nozzle
[3]
Repair Implementation
[4]
4.3 Material Properties The weld filler metal is Alloy 52M [1] (Section 5.2), which is equivalent to Alloy 690. The replacement temperature nozzle is fabricated from SB-166, Alloy 690 material [1] (Section 5.2) and the thermowell is fabricated from SA-479 Type 316 or SA-182 F316 austenitic stainless steel [5] (p. C1).
Table 4-1: Material Properties Values taken from [2]
Material Sm @ 70 F Sm / Sy @ 700 F E @ 70 F
#)
Alloy 690 23.3 ksi 23.3 ksi / 27.5 ksi 30.3E6 psi 7.7E-6 in/in/F 316 SS 20.0 ksi 16.3 ksi / 18.2 ksi 28.3E6 psi 8.5E-6 in/in/F 4.4 Applicable Loads Loads for the thermowell nozzles are taken from Appendix B (p. 144) of reference [6]. Enveloping loads for the various instrumentation nozzles are considered in this analysis. The use of these loads is very conservative as the note at the bottom of p. 144 of reference [6] indicates that there are no specified external loads for the temperature nozzle. SSE loads are calculated as 2(OBE) based on discussion in reference [6] (Sections 4.7.1, 4.7.2, p. C-17) which indicates that SSE horizontal acceleration is 2.0 g and OBE horizontal acceleration is 1.0 g. Evaluation below demonstrates that actual loads are bounded.
Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 10 Table 4-2: Deadweight Loads Line No.
Loadcase Fa (lb)
(axial)
Fb (lb)
Fc (lb)
Ma (ft-lb)
(torsion)
Mb (ft-lb)
Mc (ft-lb)
RC-019/RC-020 Deadweight 258 2
0 0
0 0
RC-021/RC-023 Deadweight
-10 0
0 0
2
-2 RC-022 Deadweight 156
-1 0
28.8 0
0 RC-029 Deadweight 314 86 0
0 0
8 Maximum Deadweight 314 86 0
28.8 2
8 Table 4-3: Seismic Loads Line No.
Loadcase Fa (lb)
(axial)
Fb (lb)
Fc (lb)
Ma (ft-lb)
(torsion)
Mb (ft-lb)
Mc (ft-lb)
RC-019/RC-020 Seismic OBE 61 0
317 0
29 0
RC-021/RC-023 Seismic OBE 2
9 15 44 11 6
RC-022 Seismic OBE 77 0
206 29 19 0
RC-029 Seismic OBE 187 43 51 13 5
4 Maximum Seismic OBE 187 43 317 44 29 6
Deadweight + OBE Seismic Moments:
Ma
= 28.8 ft-lb + 44 ft-lb
= 72.8 ft-lb Mb
= 2 ft-lb + 29 ft-lb
= 31 ft-lb Mc
= 8 ft-lb + 6 ft-lb
= 14 ft-lb Total
= 80.4 ft-lb Deadweight + SSE Seismic Moments:
Ma
= 28.8 ft-lb + 2(44 ft-lb)
= 116.8 ft-lb Mb
= 2 ft-lb + 2(29 ft-lb)
= 60 ft-lb Mc
= 8 ft-lb + 2(6 ft-lb)
= 20 ft-lb Total
= 132.8 ft-lb Note: Ma, Mb, Mc combined by SRSS in accordance with Section 4.7 of reference [6] (pp. C-17 and C-18).
Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 11 Determine Nozzle Seismic Load from Thermowell and Temperature Detector:
Figure 4-1: Thermowell and Temperature Detector Information Dimensions from [5] (p. B1 and p. 15)
Thermowell Approximate Weight:
- W LQ 2 - (0.5 in)2)(1.75 in) + ((0.75 in)2 - (0.25 in)2)(16.5 in))(0.283 lb/in3) = 2.4 lb Thermowell and Detector Combined Weight:
Total Weight = 2.4 lb + 59.4 oz/16 oz/lb = 6.1 lb DW + SSE Seismic Load:
M = (3 g)(6.1 lb)(2.25 in)/12in/ft = 3.4 ft-lb < 80.4 ft-lb (DW + OBE Moment Load) OK Where:
DW + SSE Acceleration = 1 g (DW) + 2 g (SSE) = 3 g (from above)
Distance to CG = 2.25 in (Fig 4-1)
Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 12 4.5 Plant Transients Plant transients are defined in reference [6]. Table 1 from that document provides the following information. As shown in the table, the significant normal and upset condition transients applicable to the instrumentation nozzle weld are the heatup, cooldown, reactor trip/loss of reactor coolant flow/loss of load, OBE, and plant leak test.
This gives a total number of 1880 cycles, which will be used in the fatigue analysis. Note that the 10 cycles of hydrotest are not required to be considered in accordance with NB-3657 and NB-3226 of reference [2].
[
]
Table 4-4: Plant Transient Cycles Transient Lifetime Occurrences Condition Ref. [6]
Figure / Paragraph Heatup 500 Normal Figure 2 Cooldown / Flooding 500 Normal Figure 2 Plant Loading 1E6 Normal
+/- 100 psi
+/- 20 F Plant Unloading 10% Step Load Increase 10% Step Load Decrease Normal Plant Variation Reactor Trip 480 Upset Figure 3 Loss Reactor Coolant Flow Loss of Load Operational Basis Earthquake 200 Upset N/A Safe Shutdown Earthquake 1
Faulted N/A Safe Shutdown Earthquake and Pipe Rupture 1
Faulted N/A Loss of Secondary Pressure 1
Faulted Figure 4 Hydrostatic Test 10 Test N/A Plant Leak Test 200 Test Isothermal Conditions 5.0 CALCULATIONS 5.1 Pressure Sizing Calculation As discussed in Section 2.0, the required weld size is determined by calculating the required thickness of an equivalent pipe and then specifying the weld in accordance with ASME NB-4427, which requires the leg length to be greater than or equal to 1.09 times the nominal wall thickness of the pipe.
Pipe Minimum Thickness [2] (NB-3641.1):
=
2(+ ) + =
(2500 )
2(
+ (2500 )(0.4)) + 0 = 0.097 Where:
P
= Design Pressure = 2500 psia (Section 4.1)
Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 13 Do
= Outside Diameter
[
]
[3]
Sm
= Design Stress Intensity = 16.3 ksi (Section 4.3) y
= 0.4
[2](NB-3641.1)
A
= Additional Compensatory Thickness = 0
[2](NB-3641.1)
Required Weld Size
[
] (P = 2500 psi, T = 700 F) [
]
= 1.09= 1.09 Ratio
=
=
0.375
=
Where:
Actual = Design Weld Size = 0.375 in
[4]
[
]
5.2 Stress Evaluation As shown in reference [6], and discussed in Section 4.4 of this document, the temperature instrument nozzle does not have external loads. However, this analysis conservatively applies the deadweight plus seismic loads shown in Section 4.4 for analysis purposes. As discussed in Section 2.0, the evaluation is performed in accordance with NB-3600 of reference [2].
5.2.1 NB-3652 Design Conditions (Eq. 9) 1 2+ 2 2=
(2500 )
2
+
2 (80.4 )12
=
< 1.5= 24.4 Allowable = 1.5Sm = 1.5(16.3 ksi) = 24.4 ksi Ratio = [
] / 24.4 ksi = [
]
Where:
B1
= 0.75(tn/Cx) [
]
[2] (Table NB-3681(a)-1)
B2
= 1.5(tn/Cx) [
]
[2] (Table NB-3681(a)-1)
Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 14 Cx
= Weld Leg = 0.375 in
[4]
Mi
= DW + OBE Resultant Moment = 80.4 ft-lb (Section 4.4)
P
= Design Pressure = 2500 psi (Section 4.1)
Do
= [
]
t
= [
]
Di
= [
]
I
0RPHQWRI,QHUWLD Do4 - Di4) = [
]
Sm
= Design Stress Intensity at Design Conditions = 16.3 ksi (Section 4.3) 5.2.2 NB-3653.1 Level A Service Limits (Primary + Secondary Stress Intensity Range) (Eq. 10) 1 2+ 2 2+ 3ll
=
(2500 )
2
+
2 (80.4 )12
+
=
Allowable = 3Sm = 3(16.3 ksi) = 48.9 ksi Ratio = [
] / 48.9 ksi = [
]
Where:
C1
= 1.8(tn/Cx) [
]
[2] (Table NB-3681(a)-1)
C2
= 2.1(tn/Cx) [
]
[2] (Table NB-3681(a)-1)
C3
= 2.0
[2] (Table NB-3681(a)-1)
Cx
= Weld Leg = 0.375 in
[4]
Mi
= Range of Moment (Use DW + OBE Resultant Moment) = 80.4 ft-lb (Section 4.4)
Po
= Range of Service Pressure (Use Design Pressure) = 2500 psi (Section 4.1)
Do
= [
]
t
= [
]
Di
= [
]
I
= Moment of Inertia [
]
Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 15 Eab
= Average Youngs Modulus at cold temperature on sides a/b of material discontinuity [
]
(Section 4.3) a
= Thermal Expansion Coefficient on Side a of material discontinuity
[
]
(Section 4.3) b
= Thermal Expansion Coefficient on Side b of material discontinuity
[
]
(Section 4.3)
Ta
= Range of Average Temperature on Side a of material discontinuity
[
]
(Section 2.0)
Tb
= Range of Average Temperature on Side b of material discontinuity
[
]
(Section 2.0)
Sm
= Design Stress Intensity at Design Conditions = 16.3 ksi (Section 4.3) 5.2.3 NB-3653.2 Level A Service Limits (Peak Stress Intensity Range) (Eq. 11)
[
]
= 11 2+ 22 2+
1 2(1 ) 3l1l + 33ll +
1 1 l2l
= 3.0 (2500 )
2
+ 2.0 2
(80.4 )12
+3.0(2.0)
=
Where:
K1
= 3.0
[2] (Table NB-3681(a)-1)
K2
= 2.0
[2] (Table NB-3681(a)-1)
K3
= 3.0
[2] (Table NB-3681(a)-1)
[
]
5.2.4 NB-3653.3 Alternating Stress Intensity
[
]
=
2 =
2 Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 16 5.2.5 NB-3653.4 Cumulative Usage Factor
[
]
[
]
5.2.6 NB-3656 Level D Service Limits (Eq 9) 1 2+ 2 2=
(2500 )
2
+
2 (132.8 )12 =
Allowable = Min(3Sm, 2Sy) = Min(3(16.3 ksi), 2(18.2 ksi)) = 36.4 ksi Ratio = [
] / 36.4 ksi = [
]
Where:
B1
= 0.75(tn/Cx) [
]
[2] (Table NB-3681(a)-1)
B2
= 1.5(tn/Cx) [
]
[2] (Table NB-3681(a)-1)
Cx
= Weld Leg = 0.375 in
[4]
P
= Design Pressure = 2500 psia (Section 4.1)
Mi
= DW + SSE Resultant Moment = 132.8 ft-lb (Section 4.4)
Do
= [
]
t
= [
]
Di
= [
]
I
= Moment of Inertia = [
]
Sm
= Design Stress Intensity at Design Conditions = 16.3 ksi (Section 4.3)
Sy
= Yield Strength at Design Conditions = 18.2 ksi (Section 4.3)
6.0 CONCLUSION
Table 6-1 provides a listing of the calculated stresses and applicable ratios to allowable.
Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 17 Table 6-1: Summary of Results Section/Calculation Result Allowable Ratio Section 5.1 / Weld Sizing 0.375 in Section 5.2.1 / Primary Stress - Design Conditions 24.4 ksi Section 5.2.2 / Primary + Secondary Stress Intensity Range 48.9 ksi Section 5.2.3 / Peak Stress Intensity Range N/A Section 5.2.4 / Alternating Stress Intensity N/A Section 5.2.5 / Cumulative Usage Factor 1.0 Section 5.2.6 / Primary Stress - Level D Service Limits 36.4 ksi Controlled Document
Document No. 32-9370731-000 PROPRIETARY Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis Page 18
7.0 REFERENCES
1.
Framatome Specification 08-9370351-001, Palo Verde Unit 1 Pressurizer Temperature Nozzle Modification.
2.
ASME Boiler and Pressure Vessel Code,Section II, Part D,Section III, Division 1, Subsection NB and Appendices, 2013 Edition.
3.
Framatome Drawing 02-8152712-C-002, Palo Verde Unit 1 Pressurizer Temperature Nozzle.
4.
Framatome Drawing 02-8152574-E-001, Palo Verde Unit 1 Pressurizer Lower Shell Temperature Nozzle Repair.
5.
APS Specification N001-0604-00107, Thermowell Specification (Contained in Framatome Document 38-9370474-001).
6.
Palo Verde Specification MN725-A00945, Rev. 8, Design Specification Palo Verde Generating Station Units 1, 2 and 3 Pressurizer Assembly for Arizona Public Service (Contained in Framatome Document 38-9370474-001).
Controlled Document Document No. 32-9370732-000, PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification
Page 1 of 16 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY CALCULATION
SUMMARY
SHEET (CSS)
Document No.
32 9370732 000 Safety Related: Yes No Title PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification PURPOSE AND
SUMMARY
OF RESULTS:
PURPOSE:
During the Fall 2023 outage at the Palo Verde Nuclear Generating Station Unit 1 (PVNGS-1), a leak was found in the weld area of the pressurizer (PZR) lower shell temperature nozzle. A nozzle repair will be performed to replace the existing outer diameter J-groove weld and weld pad with a nickel-based alloy material with low susceptibility to Primary Water Stress Corrosion Cracking (PWSCC). A new Alloy 690 replacement nozzle will also be installed. The purpose of this evaluation is to perform a one cycle justification (OCJ) to assess the suitability of leaving the original, as-left J-Groove weld (ALJGW) in the PZR. The existing flaw evaluation for the same nozzle repair in 1992 is reviewed and used as the basis to justify one additional cycle following the repair in 2023, equivalent to [
] years total of flaw growth. In addition, a limit load analysis is done, which demonstrates the primary stress limits of NB-3000, assuming a local area reduction of the pressure retaining membrane that is equal to the area of the projected flaw are met, since this analysis is not contained in the existing ALJGW evaluation.
RESULTS:
It is demonstrated by comparison to the previous ALJGW fatigue crack growth evaluation, the 2013 ASME Code,Section XI, IWB-3612 requirements for fracture toughness and Code Case N-749 criteria are met for at least one fuel cycle (18 months) following the repair in 2023 based on the transient input provided in Reference [1]. In addition, the primary stress limits requirements of NB-3000 of ASME Section III are met by a limit load analysis, which considers a local area reduction of the pressure retaining membrane of the nozzle opening that includes the area of the JGW and a conservatively bounding flaw sized for [
] years total of flaw growth. Based on the flaw evaluation, the projected ALJGW flaw size, considering the fatigue crack growth and corrosion of the PZR shell base metal, satisfies the LEFM and EPFM criteria for all applicable design conditions including emergency/faulted conditions for at least one fuel cycle (18 months).
FRAMATOME INC. PROPRIETARY This document and any information contained herein is the property of Framatome Inc. (Framatome) and is to be considered proprietary and may not be reproduced or copied in whole or in part. This document shall not be furnished to others without the express written consent of Framatome and is not to be used in any way which is or may be detrimental to Framatome. This document and any copies that may have been made must be returned to Framatome upon request.
If the computer software used herein is not the latest version per the EASI list, AP 0402-01 requires that justification be provided.
THE DOCUMENT CONTAINS ASSUMPTIONS THAT SHALL BE VERIFIED PRIOR TO USE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT:
CODE/VERSION/REV CODE/VERSION/REV Yes No ANSYS v19.2 (See Section 5.1)
Controlled Document
Document No. 32-9370732-000 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 2 Review Method: Design Review (Detailed Check)
Alternate Calculation Does this document establish design or technical requirements? YES NO Does this document contain Customer Required Format? YES NO Signature Block Name and Title (printed or typed)
Signature P/R/A/M and LP/LR Date Pages/Sections Prepared/Reviewed/Approved Kaihong Wang Advisory Engineer LP See Signature All except Sections 5.0 and 6.2.
Jennifer Nelson Principal Engineer LR See Signature All except Sections 5.0 and 6.2.
Luziana Matte Advisory Engineer P
See Signature Sections 5.0 and 6.2.
Martin Kolar Principal Engineer R
See Signature Sections 5.0 and 6.2.
Tim Schmitt Manager A
See Signature All.
Notes:
P/R/A designates Preparer (P), Reviewer (R), Approver (A);
LP/LR designates Lead Preparer (LP), Lead Reviewer (LR);
M designates Mentor (M)
In preparing, reviewing, and approving revisions, the lead preparer/reviewer/approver shall use All or All except
___ in the pages/sections reviewed/approved. All or All except ___ means that the changes and the effect of the changes on the entire document have been prepared/reviewed/approved. It does not mean that the lead preparer/reviewer/approver has prepared/reviewed/approved all the pages of the document.
With Approver permission, calculations may be revised without using the latest CSS form. This deviation is permitted when expediency and/or cost are a factor. Approver shall add a comment in the right-most column that acknowledges and justifies this deviation.
Project Manager Approval of Customer References and/or Customer Formatting (N/A if not applicable)
Name (printed or typed)
Title (printed or typed)
Signature Date Comments N/A N/A N/A N/A N/A
Controlled Document
Document No. 32-9370732-000 0402-01-F01 (Rev. 021, 03/12/2018)
PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 3 Record of Revision Revision No.
Pages/Sections/Paragraphs Changed Brief Description / Change Authorization 000 All Initial release. The Content of this document is identical to 32-9370513-000, except that proprietary information is redacted.
Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 4 Table of Contents Page SIGNATURE BLOCK............................................................................................................................. 2 RECORD OF REVISION....................................................................................................................... 3 LIST OF TABLES.................................................................................................................................. 5 LIST OF FIGURES................................................................................................................................ 5
1.0 INTRODUCTION
........................................................................................................................ 6 2.0 PURPOSE AND SCOPE............................................................................................................ 7 3.0 ANALYTICAL METHODOLOGY................................................................................................. 7 3.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612).....................................................8 3.2 Primary Stress Limits (NB-3000).......................................................................................................8 4.0 ASSUMPTIONS......................................................................................................................... 8 4.1 Unverified Assumptions.....................................................................................................................8 4.2 Justified Assumptions........................................................................................................................8 5.0 COMPUTER USAGE................................................................................................................. 9 5.1 Hardware and Software.....................................................................................................................9 5.2 Computer files...................................................................................................................................9 6.0 EVALUATION............................................................................................................................. 9 6.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612).....................................................9 6.1.1 Review of LEFM Analysis and Results...............................................................................9 6.1.2 Review of EPFM Analysis and Results............................................................................10 6.2 Primary Stress Limit Evaluation (NB-3000).....................................................................................11 7.0
SUMMARY
OF RESULTS........................................................................................................ 15
8.0 REFERENCES
......................................................................................................................... 16 Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 5 List of Tables Page Table 5-1: Computer Files.................................................................................................................... 9 Table 6-1: PZR and Temperature Nozzle Dimensions........................................................................ 14 Table 6-2: Material Properties............................................................................................................. 14 List of Figures Page Figure 1-1: PZR Temperature Nozzle Repair - Existing (a) and Repaired (b)....................................... 6 Figure 6-1: Limit Load, Finite Element Model Mesh............................................................................ 13 Figure 6-2: Equivalent Stresses at the Final Load Step (psi)............................................................... 15 Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 6
1.0 INTRODUCTION
During the Fall 2023 outage at the Palo Verde Nuclear Generating Station Unit 1 (PVNGS-1) operated by Arizona Public Service Company (APS), a leak was found in the weld area of the pressurizer (PZR) lower shell temperature nozzle. The original Alloy 600 temperature nozzle was pre-emptively replaced in 1992 with an Alloy 690 nozzle, an Alloy 690 outer sleeve, an Alloy 82 weld pad, and an Alloy 82 nozzle to weld pad J-groove weld (Reference [1]). The leakage indication discovered in October 2023 is in the Alloy 82 J-groove weld (JGW) on the repair weld pad.
As described in Reference [2], a nozzle repair will be performed to replace the existing nozzle J-groove weld and weld pad with a nickel-base material with low susceptibility to Primary Water Stress Corrosion Cracking (PWSCC). A new Alloy 690 replacement nozzle will also be installed. The existing and repaired configurations are shown in Figure 1-1. As shown in Reference [3], the repair plan includes a contingency configuration where the bore size at the weld pad is enlarged, which is included in this analysis.
Figure 1-1: PZR Temperature Nozzle Repair - Existing (a) and Repaired (b)
(a) Existing Configuration (b) Repaired Configuration ALJGW JGW on repair weld pad Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 7 2.0 PURPOSE AND SCOPE The purpose of this evaluation is to perform a one cycle justification (OCJ) to assess the suitability of leaving the original, as-left J-groove weld (ALJGW) in the PZR following the temperature nozzle repair in accordance with Section 4.9 of Reference [2]. The ALJGW flaw evaluation performed in 2010 (N001-0604-00923 Rev. 0 and N001-0604-00924 Rev. 0 in Reference [1]) is used as the basis to demonstrate that the flaw is acceptable from the time of repair in 1992 for one additional cycle following the repair in 2023, equivalent to [
] The LEFM (linear elastic fracture mechanics, N001-0604-00923 Rev. 0) and EPFM (elastic-plastic fracture mechanics, N001-0604-00924 Rev. 0) analyses are reviewed in order to demonstrate that the previous flaw analysis results are bounding for the PVNGS-1 weld repair and the ALJGW flaw analysis of PVNGS Unit 1 is acceptable for at least one additional operating cycle (18 months). In addition, a OLPLWORDGDQDO\\VLVLVGRQHZKLFKGHPRQVWUDWHVWKHSULPDU\\VWUHVVOLPLWVRI1%DVVXPLQJDORFDODUHD
reduction of the pressure retaining membrane that is equal to the area of the projected flaw are met, since this analysis is not contained in the existing ALJGW evaluation.
The current repair modification will be accessed in several analyses documented in separate reports, and only the impact to the ALJGW flaw evaluation is addressed in this analysis such as the short sleeve and roll expansion (see Section 6.1.1, Item 4).
3.0 ANALYTICAL METHODOLOGY Since a potential flaw in the J-groove weld cannot be sized by current nondestructive examination techniques, it is conservatively assumed that the as-left condition of the remaining J-groove weld includes flaws extending through the entire Alloy 82 J-groove weld and buttering.
Since hoop stresses in the J-groove weld are generally higher than axial stresses at the nozzle penetration, the preferential direction for cracking is axial relative to the PZR shell. Therefore, a radial-axial flaw (radial with respect to the nozzle axis) in the Alloy 82 J-groove weld and buttering is postulated and would propagate by PWSCC through the weld and buttering to the interface with the low alloy steel PZR material. Any growth of the postulated as-left flaw into the PWSCC resistant low alloy steel would be by fatigue crack growth under cyclic loading conditions.
Given the emergent nature of the PVNGS-1 penetration nozzle repair, there is not sufficient time to perform a detailed plant specific life of repair finite element analysis for the ALJGW flaw during this refueling outage.
Therefore, instead, the life of repair as-left J-groove weld flaw analyses performed in 2010 for PVNGS Units 1, 2, and 3 Pressurizer temperature nozzles (Reference [1]) are used as the basis to demonstrate that the flaw is acceptable from the time of initial repair in 1992 up to one additional cycle following the repair in 2023, which is equivalent to [
] years [
] The J-groove weld flaw analyses for the repaired temperature nozzle are based on LEFM and EPFM analyses for a total of 60 years of plant operation.
The flaw evaluation is performed for one cycle of operation in accordance with IWB-3610 (LEFM method), as well as per Case N-749 (EPFM method, Reference [4]). Code Case N-749 is considered with all applicable conditions stated in Table 2 of Regulatory Guide 1.147, Revision 20 (Reference [5]).
Per IWB-3610(d) of ASME Code Section XI (Reference [6]), a component containing a flaw is acceptable for continued service during the evaluated period if the following criteria are satisfied:
- 2) the primary stress limits of NB-3000 (Reference [7]), 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.
Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 8 3.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612)
Article IWB-UHTXLUHVDVDIHW\\IDFWRURI¥IRUQRUPDOFRQGLWLRQVWREHXVHGZKHQFRPSDULQJWKHDSSOLHG
VWUHVVLQWHQVLW\\IDFWRUWRWKHPDWHULDOIUDFWXUHWRXJKQHVVDQGDVDIHW\\IDFWRURI¥IRUHPHUJHQF\\IDXOWHG
conditions and conditions where pressure is less than 20% of the Design Pressure.
A review of the LEFM and EPFM analyses documented in Reference [1] is used for the evaluation.
3.2 Primary Stress Limits (NB-3000)
Per IWB-3610(d)(2), primary stress limits of NB-3000 (Reference [7]), 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 analyses developed for the PVGNS-1. This analysis is not performed in the analyses documented in Reference [1]. Therefore, to evaluate the requirement, article NB-3228.1 of Section III 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 1.5Sm. Per NB-3112.1(a), the Design Pressure shall be used in showing compliance with this limit.
4.0 ASSUMPTIONS 4.1 Unverified Assumptions There are no unverified assumptions used in this analysis. However, it shall be noted that Reference [8] contains assumptions requiring verification that may potentially affect the analysis herein.
4.2 Justified Assumptions Assumptions listed in the LEFM analysis presented in Reference [1] remain valid in this analysis; some critical assumptions are re-stated as follows.
- 1) [
]
- 2) [
]
- 3) [
]
Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 9 5.0 COMPUTER USAGE 5.1 Hardware and Software ANSYS Version 19.2 (Reference [9]) was used in Section 6.2. [
]
The computer runs are performed under controlled access of ANSYS on the approved platform Lynchburg HPCv2. Installation testing and verification of the ANSYS code on this controlled-access system are documented in Reference [10]. Reference [10] demonstrates that ANSYS meet the requirements to be used on the HPC as a controlled access code.
[
]
[
]
5.2 Computer files The computer files for runs performed in revision 000 are listed in Table 5-1. [
]
Table 5-1: Computer Files 6.0 EVALUATION 6.1 Applied Stress Intensity Factor Acceptance Criteria (IWB-3612) 6.1.1 Review of LEFM Analysis and Results The LEFM analysis documented in Reference [1] (document ID N001-0604-00923 Rev. 0 in Reference [1])
remains valid and bounds the current nozzle repair OCJ as justified below.
- 1) Code Reconciliation: The ASME Section XI Code edition used in Reference [1] is the 2001 edition with 2003 Addenda. The 2013 edition of the same code is used in the current repair OCJ. [
] Therefore, no reconciliation of code year is needed.
Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 10
- 2) Loads: The LEFM analysis in Reference [1] considers the following loads for the fatigue crack growth calculation: [
] A projected 60-year number of cycles is used. It therefore bounds the crack growth for OCJ in terms of transient number of cycles for [
] years. Note that corrosion of the PZR base metal is not considered in Reference [1].
Considering a corrosion rate of [
] (Reference [1]) for [
] years since the last repair, corrosion may add up to [
] inch of crack growth. Based on the plot of crack growth over 60 years in Figure 34 of the LEFM analysis, the crack size at [
] years may be estimated at 20,000 cycles: for about 32,000 cycles in 60 years, [
] years will reach
[
] The crack size is about
[
] by Figure 34. The final crack size considering the corrosion may be estimated to be [
] Therefore, the results of the projected 60-year fatigue crack growth of [
] without corrosion considered remains bounding for the OCJ.
- 3) RTNDT Value: Since the LEFM analysis documented in Reference [1] is applicable to all three units at Palo Verde, [
] is used (Reference [11]), which is conservative for PVNGS-1 PZR flaw evaluation.
- 4) Repair Configuration: [
] Therefore, the results from the previous repair configuration bound the current repair configuration (including the contingency repair).
- 5) Design Transients: Applicable design transients (Normal/Upset, Emergency/Faulted) to the temperature nozzle are considered in the LEFM analysis documented in Reference [1]. The LEFM analysis concludes that the projected flaw size for 60 years of operation satisfy the IWB-3612(b) criteria for Emergency/Faulted conditions, and the IWB-3612(a) criteria for some of the Normal/Upset conditions.
Those Normal/Upset conditions not qualified to the LEFM criteria are further evaluated in the EPFM analysis.
LEFM analysis (Reference [1]) results indicate that the final crack size of [
] considering 60 years of crack growth (without corrosion) for the temperature nozzle ALJGW exceeds the criteria for [
] Therefore, an EPFM analysis is then performed for these transients as documented in Reference [1]. [
] meet the LEFM requirements and therefore do not require EPFM evaluation.
6.1.2 Review of EPFM Analysis and Results The EPFM analysis documented in Reference [1] (document ID N001-0604-00924 Rev. 0 in Reference [1]) also remains valid and bounds the current nozzle repair OCJ as demonstrated below.
ASME Section XI, Appendix K (2001 edition with 2003 Addenda) is used in the EPFM analysis performed in 2010. For the current repair, Code Case N-749 (Reference [4]) modified by NRC Regulatory Guide 1.147 (Reference [5]) will be used in the flaw evaluation. The impact of the different methodology used in the EPFM analysis is addressed in this section.
Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 11
- 1) [
]
- 2) NRC Regulatory Guide 1.147 (Reference [5]) adds the following requirements to its acceptance of Code Case N-749:
In lieu of the upper shelf transition temperature, Tc, as defined in the Code Case, the following shall be used:
Tc = 154.8°F + 0.82 x RTNDT Tc is the temperature above which the elastic plastic fracture mechanics (EPFM) method must be applied. Additionally, the NRC defines temperature Tc1 below which the linear elastic fracture mechanics (LEFM) method must be applied:
Tc1 = 95.36°F + 0.703 x RTNDT Between Tc1 and Tc, although the fracture mode is in transition from LEFM to EPFM, users should consider whether it is appropriate to apply the EPFM method.
[
]
- 3) Code Case N-749 requires the evaluation of primary stress limits per NB-3000, which is not considered in the EPFM analysis. This requirement is addressed in Section 6.2.
As discussed in Section 6.1.1, corrosion of the PZR low alloy base metal is not considered in Reference [1].
However, the results of the projected 60-year fatigue crack growth of [
] without corrosion considered remains bounding for the OCJ, where [
] years of fatigue crack growth plus corrosion is applicable.
6.2 Primary Stress Limit Evaluation (NB-3000)
The acceptance criteria of Section 3.1(c) of Code Case N-749 and IWB-3610(d)(2) require that the primary stress limits of NB-3000 (Reference [7]) 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 III of the ASME Code (Reference [7]) 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 to be used in Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 12 these calculations is 1.5Sm. Per 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 150% of the design pressure ([
] Reference [1]). In terms of finite element (FE) method results, plastic collapse of the structure is equivalent to [
]
To demonstrate this by the FE method, cladding, [
] J-groove weld, buttering material, and portions of the PZR 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 [
] of operation as calculated in Section 6.1.1.
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 and EPFM analyses as discussed in Section 6.1 using the criteria from IWB-3612 (Reference [6]) and Code Case N-749 (Reference [4]). For the purpose of the primary stress criteria, the volume removed in the FE model is bounding and conservative.
[
] The finite element mesh utilized is shown in Figure 6-1.
Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 13 Figure 6-1: Limit Load, Finite Element Model Mesh The detailed dimensions of the temperature nozzle modeled are obtained from References [1], [3], [12], and [13].
Key dimensions are listed in Table 6-1.
Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 14 Table 6-1: PZR and Temperature Nozzle Dimensions Description Value Reference(s)
Shell radius to cladding ID
[
]
[1]
Cladding thickness (minimum)
[
]
[1]
Shell thickness (minimum) 5.0 in
[1]
Original weld pad thickness
[
]
[1]
Original nozzle bore ID 1.379 in
[3] (note 1)
Repair weld pad thickness
[
]
[3]
Replacement nozzle ID
[
]
[12] and [13]
Replacement nozzle OD (at new JGW location)
[
]
[12] and [13] (note 1)
Replacement nozzle bore ID
[
]
[12] and [13] (note 1)
Note(s):
[
] The properties at the design temperature of 700°F (Reference [1]) are listed in Table 6-2. The materials are considered elastic-perfectly plastic.
The value of yield strength used is based on Sm and is calculated as Sy = 1.5Sm.
Table 6-2: Material Properties Pressurizer Shell and Original Weld Pad: SA-533 Grade B Class 1 (C-Mn-Mo 0.4-0.7Ni)(1)
Temperature (°F)
)
E (psi)
-)
Sm (ksi)
Sy (ksi)(3) 700 7.44E-06 2.66E+07 0.3 26.7 40.05 Replacement Nozzle, New Weld Pad, and New J-groove W eld: Alloy 690(2)
Temperature (°F)
)
E (psi)
-)
Sm (ksi)
Sy (ksi) (3) 700 8.3E-06 2.75E+07 0.3 23.3 34.95 Note(s):
1.
Material properties from PZR shell and original weld pad per Reference [14].
2.
Material properties from replacement nozzle, new weld pad and new J-groove weld per Reference
[15].
3.
Sy = 1.5Sm.
Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 15
[
]
[
] The analysis was run up to a pressure of [
] psia, which is equal to [
]
times the design pressure, exceeding the requirement of 150% of the design pressure. The equivalent stress at the last load step is shown in Figure 6-2.
Figure 6-2: Equivalent Stresses at the Final Load Step (psi) 7.0
SUMMARY
OF RESULTS It is demonstrated by reviewing the previous evaluation of fatigue crack growth of the as-left J-groove weld flaw into the PZR low alloy steel, the ASME Code,Section XI, IWB-3612 requirements for fracture toughness and Code Case N-749 criteria are met for at least one fuel cycle (18 months) for the key transient inputs provided in Reference [1] and evaluated in Reference [1]. Based on the flaw evaluation, the projected ALJGW flaw size, considering the fatigue crack growth and corrosion of the PZR shell base metal, satisfies the LEFM and EPFM criteria for all applicable design conditions including emergency/faulted conditions for at least one fuel cycle (18 months).
In addition, the primary stress limits requirements of NB-3000 of ASME Section III are met by a limit load analysis, which considers a local area reduction of the pressure retaining membrane of the nozzle opening that includes the area of the JGW and a conservatively bounding flaw sized for [
] years total of flaw growth.
Controlled Document
Document No. 32-9370732-000 PROPRIETARY PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification Page 16
8.0 REFERENCES
1.
Framatome Document 38-9370474-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023.
2.
Framatome Document 08-9370351-001, Specification for Palo Verde Unit 1 Pressurizer Temperature Nozzle Modification.
3.
Framatome Drawing 02-8152574E-001, Palo Verde Unit 1 Pressurizer Lower Shell Temperature Nozzle Repair.
4.
ASME Code Case N-749, Alternative Acceptance Criteria for Flaws in Ferritic Steel Components Operating in the Upper Shelf Temperature Range,Section XI, Division 1.
5.
U.S. NRC Regulatory Guide 1.147, Revision 20, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1.
6.
ASME Boiler and Pressure Vessel Code Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, 2013 Edition.
7.
ASME Boiler and Pressure Vessel Code Section III, Rules for Construction of Nuclear Facility Components, Division 1, Subsection NB, 2013 Edition.
8.
Framatome Document 51-9370417-000, Corrosion Evaluation for Palo Verde Pressurizer Temperature Nozzle Weld Repair.
9.
ANSYS Finite Element Computer Code, Version 19.2, ANSYS Inc., Canonsburg, PA.
- 10. Framatome Document 32-9298958-000, Controlled Access of ANSYS on the HPC.
- 12. Framatome Drawing 02-8152712-C-002, Palo Verde Unit 1 Pressurizer Temperature Nozzle.
- 13. Framatome Drawing 02-8152799-C-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Overbore Contingency.
- 14. ASME Boiler and Pressure Vessel Code,Section III, Nuclear Power Plant Components, Division 1, 1971 Edition including Addenda through Winter 1973.
- 15. ASME Boiler and Pressure Vessel Code,Section II, Part D Properties (Customary) Materials, 2013 Edition, no Addenda.
Controlled Document Document No. 51-9370657-000, Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification
20004-026 (08/12/2020)
Page 1 of 19 Framatome Inc.
Engineering Information Record Document No.:
51 9370657 -
000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Controlled Document
20004-026 (08/12/2020)
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 2 Safety Related? YES NO Does this document establish design or technical requirements? YES NO Does this document contain assumptions requiring verification? YES NO Does this document contain Customer Required Format? YES NO Signature Block Name and Title/Discipline Signature P/LP, R/LR, M, A-CRF, A Date Pages/Sections Prepared/Reviewed/
Approved or Comments Trevor Eggleston Engineer I P
All Steve Fyfitch Engineering Consultant M
All Sarah Davidsaver Advisory Engineer R
All Tim Schmitt MSAU Manager A
All Note:
P/LP designates Preparer (P), Lead Preparer (LP)
M designates Mentor (M)
R/LR designates Reviewer (R), Lead Reviewer (LR)
A-CRF designates Project Manager Approver of Customer Required Format (A-CRF)
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Name (printed or typed)
Title (printed or typed)
Signature Date Jordan Boston Project Manager
Controlled Document
20004-026 (08/12/2020)
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 3 Record of Revision Revision No.
Pages/Sections/
Paragraphs Changed Brief Description / Change Authorization 000 All Origin of document. Redacted proprietary information is marked by bold brackets. The corresponding proprietary document is 51-9370417-000.
Controlled Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 4 Table of Contents Page SIGNATURE BLOCK............................................................................................................................. 2 RECORD OF REVISION....................................................................................................................... 3 LIST OF TABLES.................................................................................................................................. 5 LIST OF FIGURES................................................................................................................................ 5 1.0 PURPOSE................................................................................................................................. 6 2.0 ASSUMPTIONS......................................................................................................................... 6
3.0 BACKGROUND
......................................................................................................................... 6 4.0 INDUSTRY OCCURENCES OF EXPOSED CARBON/LOW ALLOY STEEL BASE METAL....................................................................................................................................... 8 5.0 CORROSION OF LOW ALLOY STEEL EXPOSED TO RCS..................................................... 9 5.1 General Corrosion.......................................................................................................... 9 5.1.1 General Corrosion Experimental Data.............................................................. 9 5.1.2 Oxygen Concentration in the Modified Area................................................... 10 5.1.3 Pressure Boundary Leakage (Wastage)......................................................... 10 5.1.4 General Corrosion Rates................................................................................ 10 5.1.5 One Cycle General Corrosion Projection........................................................ 11 5.2 Crevice Corrosion......................................................................................................... 11 5.3 Galvanic Corrosion....................................................................................................... 12 5.4 Stress Corrosion Cracking............................................................................................ 12 5.5 Hydrogen Embrittlement............................................................................................... 13 6.0 CORROSION OF ALLOY 690 AND FILLER METAL ALLOY 52M............................................ 13 6.1 General Corrosion........................................................................................................ 13 6.2 Crevice Corrosion......................................................................................................... 14 6.3 Galvanic Corrosion....................................................................................................... 14 6.4 Low Temperature Crack Propagation........................................................................... 14 6.5 Stress Corrosion Cracking............................................................................................ 14 7.0 SCC SUSCEPTIBILITY OF TYPE 316 THERMOWELL ADJACENT TO ALLOY 52M SOCKET WELD....................................................................................................................... 15
8.0 CONCLUSION
S....................................................................................................................... 16
9.0 REFERENCES
......................................................................................................................... 17 Controlled Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 5 List of Tables Page Table 5-1: [
]............... 11 List of Figures Page Figure 3-1: Schematic of Existing Temperature Nozzle Configuration [2].............................................. 7 Figure 3-2: Schematic of Repaired Temperature Nozzle Configuration Without Overbore [2]............... 7 Figure 3-3: Detailed Schematic of Figure 3-2, Detail A without Nozzle Installation or Overbore
[2]....................................................................................................................................... 8 Controlled Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 6 1.0 PURPOSE The purpose of this document is to evaluate potential corrosion mechanisms arising from replacement of TE-101, the lower shell temperature nozzle in the Palo Verde Generating Station (PVGS) Unit 1 pressurizer, for a one cycle justification (OCJ) of the repair. The materials with potential corrosion concerns evaluated herein are the exposed low alloy steel base metal (SA-533 GR B, Class 1) of the lower shell, the Alloy 690 outer sleeve and nozzle, the Alloy 52M weld metals, and the Type 316 thermowell, as required by Section 4.6 of Reference 1.
2.0 ASSUMPTIONS Assumptions Requiring Verification 1.
It is assumed the proportions of time that Palo Verde Unit 1 will be in the operating, shutdown, and startup conditions, during the operating cycle for which this document applies (i.e., operating cycle 25),
will be the same as those indicated by historical operation data [19].
2.
Palo Verde Unit 1 will maintain RCS primary water chemistry in accordance with the EPRI PWR Primary Water Chemistry Guidelines [40] during the operating cycle for which this document applies (i.e., operating cycle 25).
3.0 BACKGROUND
A leak in the Alloy 82 partial joint penetration outer weld of the pressurizer lower shell temperature nozzle has been identified at PVGS Unit 1, requiring replacement of nozzle components in a nozzle repair during the October 2023 refueling outage (1R24).
The pressurizer temperature nozzle at PVGS Unit 1 was previously modified from the original construction as part of a mitigation campaign in response to a leak identified at one of the other instrument nozzles on the pressurizer. [
] as depicted in Figure 3-1.
The repair of the temperature nozzle involves removal of the existing nozzle and exterior weld pad, as well as the associated exterior J-groove welds, followed by trimming and roll expanding the existing Alloy 690 outer sleeve.
A replacement temperature nozzle, thermowell, weld pad outboard of the structural weld pad and associated welds, J-groove weld, and thermowell-to-nozzle welds will be installed. The replacement temperature nozzle will be fabricated from Alloy 690, the replaced weld pad welds will be fabricated with Alloy 52M weld metal, and the replacement thermowell will be fabricated from Type 316 stainless steel [1]. A cavity will be created between the temperature nozzle and the lower pressurizer shell by the repair (Location A in Figure 3-2). Low alloy steel may also be exposed behind the nozzle sleeve even after its roll expansion (Location B in Figure 3-2). This exposed low alloy steel base metal creates corrosion concerns that must be evaluated. Figures 3-2 and 3-3 show the repair configuration and subject locations if an overbore is not implemented. An overbore that further enlarges the nozzle bore diameter from the planned repair design may be implemented [
] Dimensions for the overbore configuration can be found in
[2].
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Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 7 Figure 3-1: Schematic of Existing Temperature Nozzle Configuration [2]
Figure 3-2: Schematic of Repaired Temperature Nozzle Configuration Without Overbore [2]
Controlled Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 8 Figure 3-3: Detailed Schematic of Figure 3-2, Detail A without Nozzle Installation or Overbore [2]
4.0 INDUSTRY OCCURENCES OF EXPOSED CARBON/LOW ALLOY STEEL BASE METAL The carbon or low alloy steel components in the pressurizer, reactor vessel, and the steam generator exposed to pressurized water reactor (PWR) reactor coolant system (RCS) primary coolant are clad with either stainless steel or nickel-base alloy to prevent corrosion of the carbon or low alloy steel base metal. Throughout the operating history of domestic PWRs, there have been many cases where a localized area of the carbon or low alloy steel 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 in Reference [39], which include repairs over the last approximately 20 years. Details of some examples are listed below:
1960s Yankee-Rowe reactor vessel - Surveillance capsules fell from holder assemblies to the bottom of the vessel, releasing test specimens and other debris, leading to perforations in the cladding.
1990 ANO 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. (LER 313-1990-021) 1991 Oconee-Unit 1 steam generator - A misdrilled tubesheet hole in the upper tubesheet of one of the steam generators, during plugging operation in 1991, led to exposure of a small area of unclad tubesheet to primary coolant. [Note: This area of the tubesheet has since been patched and is no longer exposed to coolant.
1994 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) 1997 Oconee-Unit 1 OTSG manway - During the end-of-cycle (EOC) 17 refueling outage, a degraded area was observed in the bore of the 1B once through steam generator (OTSG). Subsequent inspection revealed a 1/32 to 1/16 deep, 1 wide, and 4 long circumferential damaged area to the cladding surface of the manway opening. The exposure of the base metal was confirmed by etching.
2001 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, 302-2001-004, 289-2001-002, 280-2001-003) 2002 CRDM repairs at Oconee Unit 1 and Oconee Unit 2. (LER 269-2002-003, 270-2002-002)
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Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 9 2003 CRDM/CEDM repairs at St. Lucie Unit 2 and Millstone Unit 2, half nozzle repairs of STP-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 reactor vessel bottom-mounted instrument nozzles after a leak was identified at Palo Verde Generating Station, Unit 3 (LER 2013-001-01) 2017 Half-nozzle repair on reactor vessel head instrument nozzle after a leak was identified at Limerick Generating Station, Unit 2 (LER 2017-004-01) 2020 Half-nozzle repair on reactor pressure vessel instrument nozzle after a leak was identified at Peach Bottom Atomic Power Station Unit 2 (LER 2020-002-00)
In most of these instances, carbon or low alloy steel base metal was exposed to primary coolant in a localized area. Each plant returned to normal operation with the base metal exposed; in the case of Yankee-Rowe, the vessel operated for roughly 30 years with the base metal exposed.
5.0 CORROSION OF LOW ALLOY STEEL EXPOSED TO RCS Several types of corrosion can occur when carbon and low alloy steel base metal are exposed to primary coolant.
'XULQJRSHUDWLQJFRQGLWLRQVWKHSULPDU\\FRRODQWLVGHDHUDWHGDQGDWKLJKWHPSHUDWXUH a GHSHQGLQJRQWKH
location within the RCS. For small bore temperature nozzles in the pressurizer, the RCS flow rate in the gap between the new nozzle and the pressure vessel shell [
] during operating conditions.
[
] During shutdown conditions, the primary coolant temperature approaches70-100 and may become aerated, stagnant, and/or uncovered depending on the location within the RCS. During startup FRQGLWLRQVWKHSULPDU\\V\\VWHPLVPRVWO\\GHDHUDWHGDQGWHPSHUDWXUHULVHVIURPaWRaWKRXJKR[\\JHQ
can be trapped in the crevices of the temperature nozzle assembly. The following sections discuss the possible corrosion mechanisms for the exposed low alloy steel base metal in the nozzle repair.
5.1 General Corrosion General corrosion is defined as uniform deterioration of a surface by chemical or electrochemical reactions with the environment. Carbon and low alloy steels may be subject to general corrosion upon exposure to primary coolant. The general corrosion rates of carbon and low alloy steels during aerated and deaerated reactor coolant conditions are discussed below.
5.1.1 General Corrosion Experimental Data Many studies [3,4,5,6,7,8,9,10,11,12,13] have reported corrosion rates of carbon and low alloy steels in high temperature water. In many of the studies, the corrosion rates for carbon and low alloy steels have been observed to be similar; the corrosion data [4,5,6,10] are applicable to carbon and low alloy steels such as ASME SA-212, SA-302, SA-533, and SA-516. The Electric Power Research Institute (EPRI) has also compiled a handbook [14] on boric acid corrosion. This handbook summarizes the industry field experience with boric acid corrosion incidents, a discussion of boric acid corrosion mechanisms, and a compilation of prior boric acid corrosion testing and results.
Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 10 One evaluation was completed in response to the Yankee-Rowe incident (noted in Section 3.0); in the evaluation, ASTM A 302 Grade B low alloy steel was exposed to primary coolant in aerated and deaerated conditions
[15,16]. 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 (inch per year) - the maximum corrosion rate reported [15]. Under static conditions (i.e., stagnant) 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 [15]. The primary coolant at the locations of interest [
] resulting in very low general corrosion rates.
2WKHUVWXGLHVKDYHLQYHVWLJDWHGWKHJHQHUDOFRUURVLRQUDWHRIFDUERQVWHHOVLQERUDWHGZDWHU$WDHUDWHG
ppm B the corrosion rate was 0.017 ipy [17]. The corrosion rate at startup for SA-533 GR B has been also previously determined to be a maximum of 0.019 ipy based on a 70 hour8.101852e-4 days <br />0.0194 hours <br />1.157407e-4 weeks <br />2.6635e-5 months <br /> experiment aWLQDQDHUDWHG
solution of 723 ppm boron, 1.8 ppm Li (as LiOH), and 0.4 ppm ammonia [18]. $WLQDHUDWHGERULFDFLG
solution (1730 ppm B) the corrosion rate of the steel was 0.0147 to 0.0157 ipy [13]. At 70WKHFRUURVLRQUDWH
was shown to be significantly lower, approximately 0.002 ipy [14].
5.1.2 Oxygen Concentration in the Modified Area
[
]
5.1.3 Pressure Boundary Leakage (Wastage)
Boric acid corrosion rates under conditions outside the pressure boundary are not applicable to the subject locations inside the temperature nozzle assembly, and the repair of the temperature nozzle assembly is intended to repair the leak observed in the outer Alloy 82 welds. Since this evaluation concerns only with low alloy steel corrosion exposed to the primary coolant, boric acid corrosion outside the pressure boundary due to primary coolant leakage is not within the scope of this evaluation.
5.1.4 General Corrosion Rates
[
]
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Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 11 Table 5-1: [
]
5.1.5 One Cycle General Corrosion Projection The corrosion rate for the exposed low alloy steel is conservatively estimated to be [
] Based on the combined corrosion rate described above, [
]
[
]
[
]
Based on the very small amount of low alloy steel material loss to general [
] the exposure of the SA-533 GR B, Class 1 base metal at Locations A and B to the RCS can be justified for one operating cycle with respect to general corrosion material loss.
5.2 Crevice Corrosion
[
] creates the geometry of a crevice (high aspect ratio). The environmental conditions in a crevice can become aggressive with time and can cause accelerated local corrosion. Experiments were conducted to determine the crevice corrosion rate of low alloy steel. The results indicate that the crevice corrosion rate for both aerated and deaerated conditions is less than the respective general corrosion rate [8,15]. Operating experience from PWRs and Naval reactor programs shows that crevice corrosion is not normally a concern in PWR systems [11].
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Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 12 Several corrosion studies have examined crevice corrosion in the gaps between [
]
There is evidence that crevice corrosion is not a common concern in PWR systems, the rate of crevice corrosion has been experimentally shown to be lower than that of the general corrosion rate of SA-533 GR B, Class 1 in primary coolant, and operating experience shows crevices becoming filled with corrosion product over time.
Therefore, crevice corrosion is not expected to be a concern for one operating cycle for this repair.
5.3 Galvanic Corrosion Galvanic corrosion may occur when two dissimilar metals in contact are exposed to a conductive solution or coupled together. The larger the electrochemical potential (ECP) difference between the two metals, the greater the likelihood of galvanic corrosion occurring. Low alloy steel is more anodic than nickel-base alloys [32] and could therefore be subject to galvanic attack when coupled and exposed to reactor coolant.
Several corrosion tests were performed to determine the influence of coupling between low alloy and austenitic stainless steel. Austenitic stainless steels have approximately the same ECP as the Alloy 690 nickel based alloys used in this repair [32]. Therefore, galvanic corrosion studies of low alloy steel and stainless steel give insight into the galvanic corrosion of low alloy/carbon steel and nickel based alloys. 6SHFLPHQVPDGHIURPFKURPLXP
steel coupled to Type 304 stainless steel were exposed to aerated water at 260°C (500°F) for 85 days (~2000 hours) with no evidence of galvanic corrosion. In the test above, the corrosion rates were not affected by coupling
[12]. Additionally, results of the NRCs boric acid corrosion test program have shown that the ECP difference between ASTM A533 Grade B (low alloy steel), Alloy 600, and 308 stainless steel is not significant enough to consider galvanic corrosion as a strong contributor to the overall boric acid corrosion process [35].
Additionally, galvanic corrosion of carbon steel coupled to stainless steel in boric acid solution in the absence of oxygen is about equal to the general corrosion rate [15].
Other investigations were performed for alloy steels 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 [3]. Again, the coupled specimen did not exhibit any accelerated rates of corrosion.
6SHFLPHQVPDGHIURPFKURPLXPVWHHOFRXSOHGWR7\\SHVWDLQOHVVVWHHOZHUHH[SRVHGWRDHUDWHGZDWHUDW
500°F for 85 days (~2000 hours) with no evidence of galvanic corrosion [12]. In each of the tests described above, corrosion rates were not affected by coupling and will not affect the corrosion rates discussed above.
Given the lack of evidence that the corrosion rates of low alloy steel are increased when coupled to nickel-based alloys or austenitic stainless steel alloys in PWR systems, galvanic corrosion is not expected to be a concern for one operating cycle for this repair.
5.4 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, (3) and an aggressive environment.
Under normal PWR conditions (deaerated), primary water is not a particularly aggressive environment for low alloy steel unless a departure from normal operating conditions occurs [24]. This result is attributed to the Controlled Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 13 characteristics of the PWR environment including its very low oxygen, hydrogen over pressure, and low conductivity. This service environment (i.e., deaerated; and low sulfate and chlorides) does not generally support localized corrosion of low alloy steel; therefore, the likelihood of a pit or notch forming which would contribute a stress concentrator or SCC initiation site is negligible.
A review of the relevant laboratory work and field experience appears in a report prepared for the Combustion Engineering (CE) Owners Group [25]. The conclusion of this report is that considering the environmental conditions present in a PWR, low alloy and carbon steel will not be subject to SCC.
In addition, there are field experiences that also support these observations. Noteworthy is SCC revealed in the stainless steel cladding in charging pumps [26,27]. The interdendritic cracks, present in the cladding, were determined to have blunted at the clad/low alloy steel interface with no evidence of significant general, crevice, or galvanic corrosion.
Based on experimental evidence and operating experience showing that SCC of low alloy steel is not expected based on the typical conditions found in PWR primary systems, SCC of the exposed SA-533 GR B, Class 1 is not expected to be a concern for one operating cycle for this repair.
5.5 Hydrogen Embrittlement Hydrogen embrittlement in low alloy steels results from excessive amounts of hydrogen in a metals crystal lattice. This type of damage is a mechanical/environmental failure process, which usually occurs in combination with a stress; residual, applied, or otherwise. Hydrogen embrittlement is typically observed most often in plastically deformed metals or high pressure hydrogen environments and is characterized by ductility losses and lowering of the fracture toughness [32]. High pressure hydrogen environments are not typical of PWRs. 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. Corrosion tests on low alloy steel in deaerated boric acid solutions indicated that the maximum concentration of hydrogen in the steel from corrosion was less than 2 ppm and did not increase with time [16]. 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. Additionally, lower strength low alloy steels such as SA-533, Class 1 are typically not susceptible to hydrogen embrittlement [32].
Therefore, hydrogen embrittlement is not expected to be a concern for the exposed low alloy steel for one operating cycle for this repair.
6.0 CORROSION OF ALLOY 690 AND FILLER METAL ALLOY 52M Several types of corrosion can potentially occur when austenitic nickel-base alloy base and weld metals are exposed to primary coolant. During operation, the primary coolant is deaerated and at ~650°F in the pressurizer.
The primary coolant in the repaired lower shell temperature nozzle components will [
] During shutdown, the primary coolant temperature is at 70-100°F and may become aerated. During startup conditions, the primary system is PRVWO\\GHDHUDWHGDQGWHPSHUDWXUHULVHVIURPaWR
aWKRXJKDLUFDQEHWUDSSHGLQWKHFUHYLFHVRIWKHWHPSHUDture nozzle assembly. The following subsections discuss the potential corrosion mechanisms for the Alloy 690 base and Alloy 52M weld metal shown in Figure 3-
- 2.
6.1 General Corrosion General corrosion is defined as uniform deterioration of a surface by chemical or electrochemical reactions with the environment. Nickel-base alloys (e.g., Alloy 600, Alloy 690, and their equivalent weld metals) are utilized in PWR and boiling water reactor (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 [38]. The potentially aerated environment in the pressurizer during shutdown will be more akin to a BWR environment. To date, there have Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 14 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 one operating cycle for this repair.
6.2 Crevice Corrosion The proposed modification to the lower shell temperature nozzle will create crevice conditions (high aspect ratio) associated with the Alloy 690 nozzle (Location A). However, these nickel based alloys in general have an excellent resistance to general and crevice corrosion under typical PWR conditions [28,29]. For one operating cycle, crevice corrosion is not considered a concern for Alloy 690.
6.3 Galvanic Corrosion Galvanic corrosion may occur when two different metals in contact are exposed to a conductive solution. As discussed in Section 4.3, galvanic corrosion between low alloy steel and Alloy 690 or Alloy 52M in the PWR environment is not expected to be a concern for one operating cycle for this repair.
6.4 Low Temperature Crack Propagation Low temperature crack propagation (LTCP) occurs in nickel-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 (EHORZ ). This phenomenon starts from pre-existing sharp cracks, with hydrogen at grain boundaries, and at stress intensity levels greater than a critical value.
Most of the Alloy 690 components are not plastically deformed except for the outer nozzle sleeve, which will be roll expanded. 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. Therefore, LTCP is not expected to be a concern for Alloy 690 or Alloy 52M for one operating cycle for this repair [34].
6.5 Stress Corrosion Cracking A comprehensive review of testing for the use of Alloy 690 in PWR systems cites numerous investigations and test results under a wide array of conditions, including both primary (high temperature de-oxygenated water) and secondary coolant environments. The first Alloy 690 SG went on-line in May 1989 with no reported failures of tubes as of the date of that publication (August 1997) [28]. To this date there have not been any reported Alloy 690 in-service primary water stress corrosion cracking (PWSCC) failures. More information on the PWSCC behavior of Alloy 690 can be found in MRP-258 [33].
The various test conditions of different investigations cited in the Alloy 690 literature review included temperatures to 365(690), dissolved oxygen levels < 20 ppb, tests in doped and undoped 400(752) steam, lithium concentrations up to 20 ppm, chlorides up to 300 ppb, and various heat treatments. 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(550), even in a creviced situation. Only slight intergranular cracking of Alloy 690 mill annealed (MA) was observed in slow strain rate testing (SSRT) in 360(680) high purity deaerated hydrogenated water.
SCC 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 9DULRXV$OOR\\ PDWHULDOFRQGLWLRQVZHUHWHVWHGLQFOXGLQJ0$0$WKHUPDO
WUHDWPHQW 77 0$IROORZHGE\\VROXWLRQDQQHDOLQJ 6$ FROGZRUNLQJ FROGUROOHG DQGgas tungsten arc weld (GTAW) welded specimens with matching filler metal. In tests with an environment of 6 ppm 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 FUDFNLQJ$GGLWLRQDOWHVWVFDUULHGRXWDW LQGHDHUDWHGZDWHUZLWKDS+RIfor 60 weeks as part of the same study. Alloy 690 material test conditions included solution annealed (SA) >@DQG
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>@ DQG6$thermally treated (TT) >@77 >@ $JDLQQRFUDFNLQJRI
Alloy 690 was reported [30].
Alloy 52M is a variant filler metal of Alloy 52 that includes a very small amount of boron and zirconium to improve weldability. The SCC resistance of weld metal Alloy 52 was identified as unaffected by a variety of test conditions, including primary water. No cracking occurred in weld metals containing more than ZW
chromium [28]. One study tested Alloy 52M in accelerated corrosion conditions using a weld mockup that simulated nozzle safe end repairs. The testing consisted of 400°C (752°F) steam plus hydrogen doped with 30 ppm each of fluoride, chloride, and sulfate anions. The hydrogen partial pressure was controlled at approximately 75kPa with a total steam pressure of 20 MPa. This environment has been previously used to accelerate the simulated PWSCC of nickel-base alloys. After a cumulative exposure of 2051 hours0.0237 days <br />0.57 hours <br />0.00339 weeks <br />7.804055e-4 months <br /> (equivalent to 45.6 EFPY),
no environmental degradation was detected on the surface of the Alloy 52M welds. Small micro-fissures on the surface of the Alloy 52M welds, stressed in tension, did not serve as initiation sites for environmental degradation, nor did they propagate during the tests [31]. This study indicates that the Alloy 52M weld metal in the proposed repair has a low susceptibility to PWSCC.
Based on these studies examining the PWSCC of Alloy 690 and Alloy 52M weld metal, it can be concluded that these two alloys have a low susceptibility to PWSCC. Therefore, PWSCC is not considered to be a concern in the case of the temperature nozzle repair for a one operating cycle for this repair.
7.0 SCC SUSCEPTIBILITY OF TYPE 316 THERMOWELL ADJACENT TO 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 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. Cracking can occur as intergranular stress corrosion cracking (IGSCC) or transgranular stress corrosion cracking (TGSCC) under these conditions.
Existing Configuration
[
]
Since the stainless steel material for the thermowell is not designated as a low-carbon grade [1], it is reasonable to assume that the thermowell material [
] was sensitized. Also, weld residual stresses were present in the same location [
] The potential presence of sensitization and weld residual stresses indicate that two of the three synergistic elements required for SCC (susceptible material and sustained tensile stress) have been present since the existing configuration has been present (approximately 31 years). The environment for the location of interest in the existing configuration is [
] This location could potentially accumulate dissolved oxygen and contaminants (e.g., chlorides) over time, thus causing a departure from the controlled water chemistry of the bulk reactor vessel primary coolant.
However, given that the stainless steel thermowell material adjacent to the [
] only required an aggressive environment to drive SCC (since the other two required elements of SCC were already potentially present, per the previous paragraph), and [
] the coolant in the gap is likely (at most) minimally aggressive regarding SCC of stainless steel.
Controlled Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 16 Modified Configuration
[
] However, heat input during welding is expected to be minimized and the carbon content of WKHWKHUPRZHOOPDWHULDOLVZW>@ZKLFKZLOOUHGXFHWKHOLNHOLKRRGDQGseverity of sensitization. Also, the primary coolant in the small gap between the thermowell and the nozzle base metal is expected to be [
] (i.e., minimally aggressive to SCC).
Therefore, the primary differences between the original and modified configuration at the location of interest is that, for the modified configuration, the socket weld material is Alloy 52M, the safe end base metal will be made of Alloy 690 [
] and there is a potential for a change in socket weld parameters [2]. The lower carbon content will reduce the likelihood of sensitization; in addition, the socket weld attaching the thermowell to the replacement temperature nozzle will have a PT examination performed on it [1]. As there is [
] and the modified configuration has less susceptibility to SCC for the reasons stated above, SCC is not expected for this modified configuration. Therefore, SCC of stainless steel thermowell adjacent to the socket weld is not expected to be a concern during the next operating cycle for this repair.
Based on industry experience, socket welds can be subject to fatigue. This mechanism is not considered environmental degradation and, therefore, is outside the scope of this evaluation.
8.0 CONCLUSION
S The information presented above describes the potential corrosion mechanisms that may affect the PVGS Unit 1 temperature nozzle repair, as shown in Figure 3-2.
Galvanic corrosion, hydrogen embrittlement, SCC, and crevice corrosion are not expected to be a concern for the exposed low alloy base metal resulting from the temperature nozzle repair for a one operating cycle for this repair.
Based on industry data and Framatomes experience, the corrosion rate of low alloy steel exposed to the RCS in the gap is [
] which is applicable to both Locations A and B. The long-term corrosion rate and overall release of Fe into the RCS is expected to be negligible.
Wrought Alloy 690 and Alloy 52M filler metal has been shown by extensive testing and in-reactor operating experience to have a low susceptibility to PWSCC and is not susceptible to any other forms of degradation in the PWR environment. Corrosive degradation of these two alloys is not a concern for one operating cycle.
Based on a comparison to the existing configuration, SCC of the Type 316 thermowell is not expected to be a concern during the next operating cycle for this repair.
Controlled Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 17
9.0 REFERENCES
References identified with an (*) are maintained within Palo Verde Nuclear Generating Station 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.
1.
Framatome Document 08-9370351-001, Palo Verde Unit 1 Pressurizer Temperature Nozzle Modification 2.
Framatome Document 02-8152574-E-001, Palo Verde Unit 1 Pressurizer Lower Shell Temperature Nozzle Repair October 2023 3.
Whitman, G.D., et al., A Review of Current Practice in Design, Analysis, Materials, Fabrication, Inspection, and Test, ORNL-NSIC-21, ORNL, December 1967.
4.
Vreeland, D.C., et al., Corrosion of Carbon and Low-Alloy Steels in Out-of-Pile Boiling Water Reactor Environment, Corrosion, Vol 17(6), June 1961, p. 269.
5.
Vreeland, D.C., et al., Corrosion of Carbon and Other Steels in Simulated Boiling Water Reactor Environment: Phase II, Corrosion, Vol 19(10), October 1962, p. 368.
6.
Uhlig, H.H., and Revie, R.W., Corrosion and Corrosion Control, John Wiley & Sons, New York, 1985.
7.
Copson, H.R., Effects of Velocity on Corrosion by Water, Industrial Engineering Chemistry, Vol 44, p.1745, 1952.
8.
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.
9.
Pearl, W.C., and G.P. Wozadlo, Corrosion of Carbon Steel in Simulated Boiler Water and Superheated Reactor Environments, Corrosion, Vol 21(8), August 1965, p. 260.
- 10. Tackett, D.E., et al., Review of Carbon Steel Corrosion Data in High Temperature, High Purity Water in Dynamic Systems, USAEC Report, WAPD-LSR (C)-134, Westinghouse Electric Corporation, October 1955.
- 11. DePaul, E.J., ed., Corrosion and Wear Handbook for Water Cooled Reactors, USAEC Report, TID-7006, 1957.
- 12. Ruther, W.E., and Hart, R.K., Influence of Oxygen on High Temperature Aqueous Corrosion of Iron, Corrosion, Vol 19(4), April 1963, p. 127t.
- 13. Howells, E., and Vaughan, L.H., Corrosion of Reactor Materials in Boric Acid Solutions, RDE-1086, Babcock & Wilcox Company, Alliance, Ohio, August 1960.
- 14. Boric Acid Corrosion Guidebook, Revision 1, TR-1000975, Electric Power Research Institute, Palo Alto, California, 2001.
- 15. 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.
- 16. Absorption of Corrosion Hydrogen by A302B Steel at 70F to 500F, WCAP-7099, Westinghouse Electric Corporation, Pittsburgh, Pennsylvania, December 1967.
- 17. Hall, J.F., et al., 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.
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Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 18
- 18. Palo Verde Generating Station Document N001-0301-00583, Low-Alloy Steel Component Corrosion Analysis Supporting Small-Diameter Alloy 600/690 Nozzle Repair/Replacement Programs, May 2004.
Contained in Framatome Document 38-9370474-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023.
- 19. Palo Verde Generating Station Document 13-MS-B041, Alloy Steel Corrosion Analysis Supporting Alloy 600/690 Nozzle Repair/Replacement, December 2021. Contained in Framatome Document 38-9370474-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023.
- 20. Framatome Document 02-8152712-C-002, Palo Verde Unit 1 Pressurizer Temperature Nozzle, October 2023.
- 22. Ferguson, M., Examination of 24-inch Tube Sheet Assembly from the 37-Tube OTSG, LR:68:2218-05:1, Babcock & Wilcox, Framatome, Inc. Proprietary, Alliance, Ohio, January 1968.
- 23. Emanuelson, R.H., et al., Results of the Operation and Examination of A 19 Tube Model Boiler Damaged to Simulate Crystal River 3-B Steam Generator, LR:81:5267-05:01, Babcock & Wilcox, Framatome, Inc. Proprietary, Alliance, Ohio, January 1968.
- 24. Scott, P.M, and Tice, D.R., Stress Corrosion in Low Alloy Steels, Nuclear Engineering and Design, Vol 119, 1990.
- 25. Hall, J.F., Low-Alloy Steel Component Corrosion Analysis Supporting Small-Diameter Alloy 600/690 Nozzle Repair/Replacement Programs, CE NPSD-1198-NP, Revision 00, February 2001. NRC Accession No. ML010540212.
- 26. Cracking in Charging Pump Casing Cladding, IE Information Notice No. 80-38, Nuclear Regulatory Commission, October 1980.
- 27. Boric Acid Corrosion of Charging Pump Casing Caused by Cladding Cracks, IE Information Notice 94-63, Nuclear Regulatory Commission, August 1994.
- 28. 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, August 1997, Amelia Island, Florida, ANS.
- 29. Saito, N., Crevice Corrosion of Austenitic Alloys in High-Temperature Water, Corrosion, Vol 54(9), p.
700
- 30. Sedriks, A.J., Schultz, J.W., and Cordovi, M.A., Inconel Alloy 690 - A New Corrosion Resistant Material, Boshoku Gijutsu, Japan Society of Corrosion Engineering, Vol 28(2), 1979.
- 31. Jacko, R.J., et. al., Accelerated Corrosion Testing of Alloy 52M and Alloy 182 Weldments, Eleventh International Conference on Environmental Degradation of Materials in Nuclear System, August 2003, ANS.
- 32. Corrosion Handbook, 9th Ed., Vol. 13, ASM International, 1987.
- 33. Materials Reliability Program: Resistance to Primary Water Stress Corrosion Cracking of Alloy 690 in Pressurized Water Reactors, MRP-258, Electric Power Research Institute, August 2009.
- 34. Demma, A., McIlree, 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.
- 35. U.S. NRC publication NUREG-1823, U.S. Plant Experience with Alloy 600 Cracking and Boric Acid Corrosion of Light-Water Reactor Pressure Vessel Materials, NRC Accession No. ML051390139.
Controlled Document
Document No.: 51-9370657-000 Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification Page 19
- 36. Pastina, B., et. al., The Influence of Water Chemistry on the Radiolysis of the Primary Coolant Water in Pressurized Water Reactors, Journal of Nuclear Materials, 264, 1999, pp. 309-318
- 37. Scott, P., A Review of Irradiation Assisted Stress Corrosion Cracking, Journal of Nuclear Materials, 211, 1994, pp. 101-122.
- 38. Wang, Y. et al., 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.
- 39. McCracken, S., and Patel, A., Elimination of the 48-Hour Hold for Ambient Temperature Temper Bead Welding with Austenitic Weld Metal, PVP2023-107489, Proceedings of the ASME 2023 Pressure Vessels & Piping Conference, Atlanta, Georgia, July 2023.
- 40. *Pressurized Water Reactor Primary Water Chemistry Guidelines, Volumes 1 and 2, Revision 7. EPRI, Palo Alto, CA, 2014. 3002000505.
- 41. Framatome Document 02-8152799-C-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Overbore Contingency, October 2023.
- 42. Framatome Document 02-1214078-D-05, Horiz. Lower Temp Nozzle, March 1992.
- 43. Palo Verde Generating Station Document Purchase Order (PO) 33208398, February 1994. Contained in Framatome Document 38-9370474-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023.
Controlled Document Document No. 51-9370728-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation
20004-026 (08/12/2020)
Page 1 of 9 Framatome Inc.
Engineering Information Record Document No.:
51 9370728 -
000 Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Controlled Document
20004-026 (08/12/2020)
Document No.: 51-9370728-000 Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Page 2 Safety Related? YES NO Does this document establish design or technical requirements? YES NO Does this document contain assumptions requiring verification? YES NO Does this document contain Customer Required Format? YES NO Signature Block Name and Title/Discipline Signature P/LP, R/LR, M, A-CRF, A Date Pages/Sections Prepared/Reviewed/
Approved or Comments Dan Ulevich Advisory Engineer P
All Mohsen Hosseinian Engineer II R
All Curtis Anderson Supervisor A
All / preparer-reviewer independence Note:
P/LP designates Preparer (P), Lead Preparer (LP)
M designates Mentor (M)
R/LR designates Reviewer (R), Lead Reviewer (LR)
A-CRF designates Project Manager Approver of Customer Required Format (A-CRF)
A designates Approver/RTM - Verification of Reviewer Independence Project Manager Approval of Customer References (N/A if not applicable)
Name (printed or typed)
Title (printed or typed)
Signature Date N/A
Controlled Document
20004-026 (08/12/2020)
Document No.: 51-9370728-000 Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Page 3 Record of Revision Revision No.
Pages/Sections/
Paragraphs Changed Brief Description / Change Authorization 000 All Original release. The Content of this document is identical to 51-9370533-001, except that proprietary information is redacted.
Controlled Document
Document No.: 51-9370728-000 Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Page 4 Table of Contents Page SIGNATURE BLOCK............................................................................................................................. 2 RECORD OF REVISION....................................................................................................................... 3 LIST OF FIGURES................................................................................................................................ 4
1.0 INTRODUCTION
/ BACKGROUND........................................................................................... 5 2.0 PRESSURIZER TEMPERATURE NOZZLE DESCRIPTION...................................................... 5 3.0 PRESSURIZER SURGE NOZZLE SCREEN DESCRIPTION.................................................... 5 4.0 CHARACTERIZATION OF POSTULATED LOOSE PARTS....................................................... 7 5.0 LOOSE PARTS EVALUATION.................................................................................................. 7
6.0 CONCLUSION
........................................................................................................................... 8
7.0 REFERENCES
........................................................................................................................... 8 List of Figures Page Figure 3-1: Location of Surge Screen and Temperature Nozzle in Lower Pressurizer.......................... 6 Document
Document No.: 51-9370728-000 Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Page 5
1.0 INTRODUCTION
/ BACKGROUND Repair work is being performed on the pressurizer lower temperature nozzle at Palo Verde Unit 1. The existing nozzle (which is itself a repair that was installed in 1992) is being removed and a new nozzle installed in its place.
The anti-corrosion outer sleeve that was part of the original repair will not be removed. It is a thin cylindrical tube which is affixed to the inboard of the pressurizer by a fillet weld to the original Inconel J-Groove weld that was abandoned in place as a result of the 1992 repair. This is shown on Reference [1], Step 4, Detail A. A section of [
] the outer sleeve at the outboard size of the pressurizer will be roll-expanded to constrain it in place (Reference [2], Step 4). Although these parts are presently known to be constrained and intact, this evaluation considers the possibility that the weld, the sleeve, or fragments of them, could break off and become loose parts within the pressurizer in the future.
2.0 PRESSURIZER TEMPERATURE NOZZLE DESCRIPTION The temperature nozzle is located relatively low in the cylindrical shell section of the pressurizer, shown in Reference [3] main view. This shows that, based on the given reference datum, the elevation of the temperature nozzle [
] is lower than the water level required to cover the pressurizer heaters [
] The normal water level is noted as [
] above the reference datum. It can therefore be determined that the temperature nozzle is submerged during normal plant operation.
3.0 PRESSURIZER SURGE NOZZLE SCREEN DESCRIPTION The surge nozzle is covered by a screen assembly, shown generally in Reference [3] main view and more detailed in Reference [4]. The surge screen is configured as a right circular cylinder with holes drilled in an array around the circumference, somewhat below mid-height. These holes direct surge flow laterally to promote mixing of the RCS water with the pressurizer bulk water during insurges. There are a total of [
] holes with a diameter of
[
] The centerline of the bottom row of holes is located about [
] above the bottom of the screen assembly. It is noted that Reference [4] shows the top plate of the screen assembly as having a [
] diameter opening, which is surrounded by [
] tapped holes, arranged in a circle with diameter of
[
] The general schematic of the screen assembly from Reference [3] main view shows a cover plate with a lifting lug bolted to the top of the screen assembly. Therefore the only flowpath through the screen assembly considered here is the array of [
] flow holes.
As shown on Reference [3] the pressurizer ID is [
] From Reference [4] the cylindrical section of the surge nozzle screen assembly has an OD of [
] The radial distance between the temperature nozzle and the surge screen is therefore [
]
A partial view of the lower section of the pressurizer is shown in Figure 3-1. Information pertinent to this loose parts evaluation is highlighted as follows:
the surge screen assembly is indicated in orange, including the location of the flow holes the temperature nozzle is indicated in red the minimum water level to cover the heating elements is indicated in blue the normal operating water level is indicated in green.
Controlled Document
Document No.: 51-9370728-000 Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Page 6 Figure 3-1: Location of Surge Screen and Temperature Nozzle in Lower Pressurizer Document
Document No.: 51-9370728-000 Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Page 7 4.0 CHARACTERIZATION OF POSTULATED LOOSE PARTS The outer sleeve OD is [
] (Reference [2], Step 1). The length of the outer sleeve that will remain in the nozzle bore is derived from Reference [2], Step 1, Step 3, Step 7 and Detail A. Step 1 shows that the distance from the PZR inner cladding to the location of the previous weld pad (which will be removed, indicated in Step 3) is [
] Step 7 and Detail A show that a counterbore will remove at least [
] of the length of the outer sleeve. Therefore the section of outer sleeve remaining will have a length less than [
]
The largest possible loose part would be if the entire remaining outer sleeve section and J-groove weld were to remain intact as a single object; it is also possible that smaller pieces or fragments of the weld and/or sleeve could break off.
5.0 LOOSE PARTS EVALUATION From Section 2.0, the temperature nozzle is submerged in the liquid space of the pressurizer during normal plant operation. Thus the sleeve and J-groove weld, or any fragments of them, will already be under water at the time they are presumed to become loose parts within the pressurizer.
The most likely scenario by far is that any pieces or fragments of the sleeve or J-groove weld that break off will drift down into the pressurizer bottom head. Pieces larger than the [
] holes in the surge nozzle screen will be trapped in the pressurizer due to being unable to pass through the screen. Even for pieces smaller than this threshold size, the most probable outcome is that they will drop down into the pressurizer bottom head and remain there. From Section 3.0, the flow holes in the surge screen begin about [
] above the connection to the pressurizer lower head. Due to the very low fluid velocity below this elevation, any parts that reach the lower pressurizer head will come to rest, and will not be lifted and transported elsewhere.
The only way for the postulated loose parts to exit the pressurizer and reach the remainder of the RCS is by passing out of the surge nozzle. For this to occur, the piece would have to be smaller than [
] (to fit through the holes in the screen); the piece would have to break free during a time when there was significant flow out of the pressurizer surge nozzle (to draw the piece toward the screen, traversing a radial distance of more than
[
]); and the piece would have to turn and pass horizontally through one of the holes in the screen before it dropped below the final row of flow holes and settled in the pressurizer lower head. These precise movements would have to occur before the piece sank below the bottom row of holes in the screen. This is a very unlikely combination of events.
In the highly unlikely event that a plant transient were to cause pressurizer water level to drop low enough so that the pressurizer emptied, any fragments of material which became loose parts in pressurizer at exactly that moment would most likely fall downward and become trapped on the pressurizer lower head. For these potential pieces to be able to exit the pressurizer, they would have to fall or be knocked inwards toward the center of the pressurizer, rather than downward; they would need to be exactly aligned with one of the holes in the surge strainer, and then pass horizontally through it. These precise movements would have to occur before the pieces fell (through the steam atmosphere) into the water below the surge screen flow holes. This combination of movements, changes of direction, and timing is not considered credible.
Controlled Document
Document No.: 51-9370728-000 Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Page 8 A previous evaluation (Reference [5]) considered the effect of broken J-groove weld fragments as loose parts in the lower RV head region, which could impact the fuel and control element assemblies (CEAs). The minimum loose part size considered in the Reference [5] evaluation is a [
] segment of J-groove weld, measuring
[
] This is comparable to the size of the potential loose parts considered here. Moreover the materials are similar, a mixture of Inconels and steel. For a fragment of the sleeve or J-groove weld from the pressurizer lower temperature nozzle to reach the lower RV head at all, a highly unlikely series of events would have to occur. First, a piece of material would have to break off and successfully traverse the path through the surge screen, described above. The piece could eventually work its way through the pressurizer surge line and reach the RC hot leg. At this point it would be drawn into the reactor coolant flow stream and be transported to the steam generator, where it would most likely impact against the tubesheet and divider plate repeatedly until it either deformed or broke into multiple smaller pieces, eventually passing through a tube. While the pieces may scrape along the inside of the tube as they pass through, this is not expected to cause any significant damage to the tubing and should not result in any leakage. The piece or pieces would then pass through the reactor coolant pump, travel down the cold leg and enter the reactor vessel. At this point the material would most likely either become trapped in the lower RV head region, or possibly approach the core entrance. The evaluation in Reference [5] considered loose parts originating in this location, and concluded that there would be a very low risk of negative impacts on incore instrumentation, CEAs or the fuel assemblies themselves. For any of the pieces of material considered here, should they reach the lower RV head region, the conclusions of Reference [5] will remain applicable.
Reference [6] and Reference [7] evaluate similar loose parts in the RV and RCS, and provide justification that there would be a very low likelihood of this type of material causing any damage to RCS components. The conclusions of these evaluations also remain applicable.
6.0 CONCLUSION
The most likely scenario is that the loose parts considered here will drop down into the pressurizer bottom head and remain there. It is unlikely that any of the pieces will be able to exit the pressurizer.
Even in the unlikely event that pieces should exit the pressurizer and reach the remainder of the RCS, there is a very low likelihood of any problems with the steam generator tubes, or with the fuel, core instrumentation, or control components.
The loose parts considered here are not expected to result in any negative consequences to safety or plant operation.
7.0 REFERENCES
- 1.
Framatome document 38-9370474-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023
[containing APS drawing N001-0604-00146-2, Temperature Nozzle Installation]
- 2.
Framatome drawing 02-8152574-E-000, Palo Verde Unit 1 Pressurizer Lower Shell Temperature Nozzle Repair
- 3.
Framatome document 38-2201972-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023
[containing APS drawing N001-0604-00009-8, 96 ID Pressurizer General Arrangement]
- 4.
Framatome document 38-2201972-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023
[containing APS drawing N001-0603-00343-1, Surge Screen Assembly]
Controlled Document
Document No.: 51-9370728-000 Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Page 9 5.
Framatome document 38-2201972-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023
[containing APS document N001-0301-00556, Palo Verde Unit 3 Bottom Mounted Instrument Nozzle Repair Westinghouse Loose Parts Evaluation]
6.
Framatome document 38-2201972-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023
[containing APS document N001-0301-00598, Palo Verde Nuclear Generating Station Unit 3 Review of Bounding Evaluations for Loose Weld Material (Proprietary)]
7.
Framatome document 38-2201972-001, PV1 Design Inputs for PZR Instrument Nozzle Repair 2023
[containing APS document N001-0301-00599, Engineering Evaluation of Loose Material through the APS Palo Verde Nuclear Generation Station Reactor Vessel (Proprietary)]
Controlled Document
Affidavits from Framatome Submitted in Accordance with 10 CFR 2.390 to Consider Enclosure 3 Attachments as Proprietary Documents
- Signed Affidavit for Document No. 32-9370429-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification
- Signed Affidavit for Document No 32-9370512-000, Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis
- Signed Affidavit for Document No 32-9370513-000, PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification
- Signed Affidavit for Document No. 51-9370417-000, Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification
- Signed Affidavit for Document No. 51-9370533-001, Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation Signed Affidavit for Document No. 32-9370429-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification
A F F I D A V I T
- 1.
My name is Philip A. Opsal. I am Manager, Product Licensing for Framatome Inc. (formally known as AREVA Inc.), and as such I am authorized to execute this Affidavit.
- 2.
I am familiar with the criteria applied by Framatome to determine whether certain Framatome information is proprietary. I am familiar with the policies established by Framatome to ensure the proper application of these criteria.
- 3.
I am familiar with the Framatome information contained in Framatome Document No. 32-9370429-000, Palo Verde Unit 1 Pressurizer Temperature Nozzle Replacement Section III One-Cycle Justification referred to herein as this Document.
Information contained in this Document has been classified by Framatome as proprietary in accordance with the policies established by Framatome for the control and protection of proprietary and confidential information.
- 4.
This Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by Framatome and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in this Document as proprietary and confidential.
- 5.
This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is requested qualifies under 10 CFR 2.390(a)(4) Trade secrets and commercial or financial information.
- 6.
The following criteria are customarily applied by Framatome to determine whether information should be classified as proprietary:
(a)
The information reveals details of Framatomes research and development plans and programs or their results.
(b)
Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service.
(c)
The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for Framatome.
(d)
The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for Framatome in product optimization or marketability.
(e)
The information is vital to a competitive advantage held by Framatome, would be helpful to competitors to Framatome, and would likely cause substantial harm to the competitive position of Framatome.
The information in this Document is considered proprietary for the reasons set forth in paragraphs 6(b), 6(c), 6(d), and 6(e) above.
- 7.
In accordance with Framatomes policies governing the protection and control of information, proprietary information contained in this Document has been made available, on a limited basis, to others outside Framatome only as required and under suitable agreement providing for nondisclosure and limited use of the information.
8.
Framatome policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.
9.
The foregoing statements are true and correct to the best of my knowledge, information, and belief.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on October 27, 2023.
Philip A. Opsal Manager, Product Licensing Framatome Inc.
Executed on October 27, 2023.
Phili A O l
Signed Affidavit for Document No 32-9370512-000, Palo Verde Unit 1 PRZR Thermowell to Instrument Nozzle Weld Design Analysis
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BBBBBBBBBBBBBBBBBBBBBBBBBBBB 3KLOLS $ 2SVDO Signed Affidavit for Document No 32-9370513-000, PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification
A F F I D A V I T
- 1.
My name is Philip A. Opsal. I am Manager, Product Licensing for Framatome Inc. (formally known as AREVA Inc.), and as such I am authorized to execute this Affidavit.
- 2.
I am familiar with the criteria applied by Framatome to determine whether certain Framatome information is proprietary. I am familiar with the policies established by Framatome to ensure the proper application of these criteria.
- 3.
I am familiar with the Framatome information contained in Framatome Document No 32-9370513-000, PVNGS-1 Pressurizer Temperature Nozzle As-Left J-Groove Weld One Cycle Justification referred to herein as this Document. Information contained in this Document has been classified by Framatome as proprietary in accordance with the policies established by Framatome for the control and protection of proprietary and confidential information.
- 4.
This Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by Framatome and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in this Document as proprietary and confidential.
- 5.
This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is requested qualifies under 10 CFR 2.390(a)(4) Trade secrets and commercial or financial information.
- 6.
The following criteria are customarily applied by Framatome to determine whether information should be classified as proprietary:
(a)
The information reveals details of Framatomes research and development plans and programs or their results.
(b)
Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service.
(c)
The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for Framatome.
(d)
The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for Framatome in product optimization or marketability.
(e)
The information is vital to a competitive advantage held by Framatome, would be helpful to competitors to Framatome, and would likely cause substantial harm to the competitive position of Framatome.
The information in this Document is considered proprietary for the reasons set forth in paragraphs 6(b), 6(c), 6(d), and 6(e) above.
- 7.
In accordance with Framatomes policies governing the protection and control of information, proprietary information contained in this Document has been made available, on a limited basis, to others outside Framatome only as required and under suitable agreement providing for nondisclosure and limited use of the information.
8.
Framatome policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.
9.
The foregoing statements are true and correct to the best of my knowledge, information, and belief.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on October 26, 2023.
Philip A. Opsal Manager, Product Licensing Framatome Inc.
Executed on October 26, 2023.
Philip A Opsal Signed Affidavit for Document No. 51-9370417-000, Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification
A F F I D A V I T
- 1.
My name is Philip A. Opsal. I am Manager, Product Licensing for Framatome Inc. (formally known as AREVA Inc.), and as such I am authorized to execute this Affidavit.
- 2.
I am familiar with the criteria applied by Framatome to determine whether certain Framatome information is proprietary. I am familiar with the policies established by Framatome to ensure the proper application of these criteria.
- 3.
I am familiar with the Framatome information contained in Framatome Document No. 51-9370417-000, Corrosion Evaluation for Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair - One Cycle Justification referred to herein as this Document.
Information contained in this Document has been classified by Framatome as proprietary in accordance with the policies established by Framatome for the control and protection of proprietary and confidential information.
- 4.
This Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by Framatome and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in this Document as proprietary and confidential.
- 5.
This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is requested qualifies under 10 CFR 2.390(a)(4) Trade secrets and commercial or financial information.
- 6.
The following criteria are customarily applied by Framatome to determine whether information should be classified as proprietary:
(a)
The information reveals details of Framatomes research and development plans and programs or their results.
(b)
Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service.
(c)
The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for Framatome.
(d)
The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for Framatome in product optimization or marketability.
(e)
The information is vital to a competitive advantage held by Framatome, would be helpful to competitors to Framatome, and would likely cause substantial harm to the competitive position of Framatome.
The information in this Document is considered proprietary for the reasons set forth in paragraphs 6(b), 6(c), 6(d), and 6(e) above.
- 7.
In accordance with Framatomes policies governing the protection and control of information, proprietary information contained in this Document has been made available, on a limited basis, to others outside Framatome only as required and under suitable agreement providing for nondisclosure and limited use of the information.
8.
Framatome policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.
9.
The foregoing statements are true and correct to the best of my knowledge, information, and belief.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on October 26, 2023.
Philip A. Opsal Manager, Product Licensing Framatome Inc.
Philip A Opsal Signed Affidavit for Document No. 51-9370533-001, Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation
A F F I D A V I T
- 1.
My name is Philip A. Opsal. I am Manager, Product Licensing for Framatome Inc. (formally known as AREVA Inc.), and as such I am authorized to execute this Affidavit.
- 2.
I am familiar with the criteria applied by Framatome to determine whether certain Framatome information is proprietary. I am familiar with the policies established by Framatome to ensure the proper application of these criteria.
- 3.
I am familiar with the Framatome information contained in Framatome Document No. 51-9370533-001, Palo Verde Unit 1 Pressurizer Temperature Nozzle Repair Loose Parts Evaluation. Information contained in this Document has been classified by Framatome as proprietary in accordance with the policies established by Framatome for the control and protection of proprietary and confidential information.
- 4.
This Document contains information of a proprietary and confidential nature and is of the type customarily held in confidence by Framatome and not made available to the public. Based on my experience, I am aware that other companies regard information of the kind contained in this Document as proprietary and confidential.
- 5.
This Document has been made available to the U.S. Nuclear Regulatory Commission in confidence with the request that the information contained in this Document be withheld from public disclosure. The request for withholding of proprietary information is made in accordance with 10 CFR 2.390. The information for which withholding from disclosure is requested qualifies under 10 CFR 2.390(a)(4) Trade secrets and commercial or financial information.
- 6.
The following criteria are customarily applied by Framatome to determine whether information should be classified as proprietary:
(a)
The information reveals details of Framatomes research and development plans and programs or their results.
(b)
Use of the information by a competitor would permit the competitor to significantly reduce its expenditures, in time or resources, to design, produce, or market a similar product or service.
(c)
The information includes test data or analytical techniques concerning a process, methodology, or component, the application of which results in a competitive advantage for Framatome.
(d)
The information reveals certain distinguishing aspects of a process, methodology, or component, the exclusive use of which provides a competitive advantage for Framatome in product optimization or marketability.
(e)
The information is vital to a competitive advantage held by Framatome, would be helpful to competitors to Framatome, and would likely cause substantial harm to the competitive position of Framatome.
The information in this Document is considered proprietary for the reasons set forth in paragraphs 6(d), and 6(e) above.
- 7.
In accordance with Framatomes policies governing the protection and control of information, proprietary information contained in this Document has been made available, on a limited basis, to others outside Framatome only as required and under suitable agreement providing for nondisclosure and limited use of the information.
8.
Framatome policy requires that proprietary information be kept in a secured file or area and distributed on a need-to-know basis.
9.
The foregoing statements are true and correct to the best of my knowledge, information, and belief.
I declare under penalty of perjury that the foregoing is true and correct.
Executed on October 23, 2023.
Philip A. Opsal Manager, Product Licensing Framatome Inc.
hilip A Opsal