Text

Enclosure 2: Relief Request ANO2-RR-23-001
	ML23020A943
Person / Time
Site:	Arkansas Nuclear
Issue date:	01/20/2023
From:	; Entergy Nuclear Operations
To:	; Office of Nuclear Reactor Regulation
Shared Package
ML23020A940	List: 2CAN012302, Relief Request ANO2-RR-23-001, Half-Nozzle Repair of Reactor Vessel Closure Head Penetration 46; ML23020A943; ML23020A944;
References
	2CAN012302
	Download: ML23020A943 (1)
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ENCLOSURE 2 2CAN012302 REQUEST FOR RELIEF ANO2-RR-23-001 (NON-PROPRIETARY)

2CAN012302 Page 1 of 29 RELIEF REQUEST ANO2-RR-23-001

1. ASME CODE COMPONENT AFFECTED Component: Reactor Vessel Closure Head (RVCH) Penetration #46 Code Class: 1 Exam. Cat.: American Society of Mechanical Engineers (ASME)

Code Case N-729-6 (Reference 3)

Item No. B4.20 Unit: Arkansas Nuclear One, Unit 2 (ANO-2)

Interval: Fifth (5th) (March 26, 2020 to March 25, 2030)

2. APPLICABLE CODE EDITION AND ADDENDA ASME Section XI, 2007 Edition through 2008 Addenda ASME Section XI Code Case N-729-6, as amended in 10 CFR 50.55a(g)(6)(ii)(D)

ASME Section III, 1968 Edition through Summer 1970 Addenda (Original Construction Code)

ASME Section III, Subsection NB, 1992 Edition

3. APPLICABLE CODE REQUIREMENTS The applicable requirements of the following ASME Boiler & Pressure Vessel (B&PV) Code and Code Cases from which relief is requested are as follows:

ASME Code,Section XI, 2007 Edition through 2008 Addenda IWB-3420 states:

Each detected flaw or group of flaws shall be characterized by the rules of IWA-3300 to establish the dimensions of the flaws. These dimensions shall be used in conjunction with the acceptance standards of IWB-3500.

2CAN012302 Page 2 of 29 IWB-3132.3 states:

A component whose volumetric or surface examination detects flaws that exceed the acceptance standards of Table IWB-3410-1 is acceptable for continued service without a repair/replacement activity if an analytical evaluation, as described in IWB-3600, meets the acceptance criteria of IWB-3600. The area containing the flaw shall be subsequently reexamined in accordance with IWB-2420(b) and (c).

ASME Code,Section III, 1992 Edition NB-5245, Partial Penetration Welded Joints, specifies progressive surface examination of partial penetration welds.

NB-5330(b) states:

Indications characterized as cracks, lack of fusion, or incomplete penetration are unacceptable regardless of length.

Code Case N-638-7, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique This Code Case provided requirements for automatic or machine gas tungsten arc welding (GTAW) of Class 1 components without the use of preheat or post-weld heat treatment. The condition imposed on this Code Case by Regulatory Guide (RG) 1.147, Revision 19 (effective at the time of implementation) is addressed below in paragraph 7.1.

Paragraph 1(g) states:

Peening may be used, except on the initial and final layers.

Paragraph 2(b) permits use of existing welding procedures qualified in accordance with previous revisions of the Code Case. When the existing welding procedure was qualified in accordance with N-638-4, the test coupon base material was post-weld heat treated to comply with paragraph 2.1(a) of the Code Case (N-638-4) which states:

The materials shall be post-weld heat treated to at least the time and temperature that was applied to the materials being welded.

4. REASON FOR REQUEST Entergy Operations, Inc. (Entergy) ANO-2 performed ultrasonic (UT) examinations of RVCH penetration nozzles in Refueling Outage 2R28 (Fall 2021), in accordance with ASME Code

2CAN012302 Page 3 of 29 Case N-729-6 (Item No. B4.20)2, and detected an axial, planar indication in Control Element Drive Mechanism (CEDM) Nozzle #46. The indication was located along the outside diameter, downhill side of the nozzle in the J-groove weld fillet region (see Figure 11). Eddy current (ECT) examination along the outside diameter of the nozzle and J-groove weld confirmed that the indication was surface connected. A supplemental liquid penetrant (PT) examination of the flaw was also performed to confirm the indication's location. The UT leak path assessment on CEDM Nozzle #46 did not provide any evidence of base material degradation along the RVCH nozzle bore. Additionally, the bare metal visual examination (Item B4.10) of the RVCH did not identify any evidence of reactor coolant leakage such as boric acid deposits or base material wastage.

The UT examination indicated that the flaw in CEDM Nozzle #46 was 0.204-inch deep and 0.400-inch long. The total length of the flaw was estimated to be 1.03-inches based on the UT and supplemental PT examinations. The PT examination also indicated that the flaw extended into the thread relief region of the nozzle while the lower tip of the flaw was approximately 0.7-inch above the bottom of the nozzle. Figure 10 shows the relative location of the nozzles in the RVCH and Figure 11 shows the general location of the axial indication.

The repair technique sometimes referred to as the half-nozzle repair, was performed to correct the identified condition on CEDM Nozzle #46. The half-nozzle repair involved machining away the lower section of the nozzle containing the flaws, then welding the remaining portion of the nozzle to the RVCH to form the new pressure boundary. The new weld also attached a replacement lower nozzle that provided a means for re-attaching the guide cone. This technique required relief from certain aspects of the ASME B&PV Code as described below.

Because of the risk of damage to the RVCH material properties or dimensions, it was not feasible to apply the post weld heat treatment (PWHT) requirements of the original Construction Code. As an alternative to the requirements of the RVCH Code of Construction, Entergy performed a modification of CEDM Nozzle #46 utilizing the Inside Diameter Temper Bead (IDTB) welding method to restore the pressure boundary of the degraded nozzle penetration. The IDTB welding method was performed with a remotely operated weld tool utilizing the machine GTAW process and the ambient temperature temper bead method with 50° F minimum preheat temperature and no PWHT. The modification described below was performed in accordance with the 2007 Edition through 2008 Addenda of ASME Section XI, Code Case N-638-7, Code Case N-729-6, and the alternatives discussed in Section 5.

2 Code Case N-729-6 as amended in 10 CFR 50.55a(g)(6)(ii)(D) and supplemented by Relief Request ANO2-ISI-022 (Reference 4)

2CAN012302 Page 4 of 29 Basic steps for the IDTB repair are:

1. Roll expansion of the nozzle above the area to be modified to stabilize the nozzle and prevent any movement when the nozzle is separated from the nozzle-to-RVCH J-groove weld.

2. Machining to remove the lower nozzle to above the J-groove weld eliminating the portions of the nozzle containing the unacceptable indication. This machining operation also establishes the weld preparation area (Refer to Figure 1).

3. PT examination of the machined area (Refer to Figure 1).

4. Welding the remaining portion of the nozzle and the new replacement Alloy 690 nozzle using Alloy 52M weld material (Refer to Figure 2).

5. Machining the weld and adjacent nozzle material to provide a surface suitable for nondestructive examination (NDE).

6. PT and UT examination of the weld and adjacent region (Refer to Figure 3).

Note the figures in this request are provided to assist in clarifying the above description.

They are not intended to provide design information such as the location of the CEDM nozzle weld relative to the inner and outer spherical radii of the RVCH.

Stresses introduced during the controlled roll expansion process implemented per design and fabrication controls did not create regions that would be more susceptible to Primary Water Stress Corrosion Cracking (PWSCC) than other regions that had been previously evaluated and found acceptable. Two fabrication parameters were controlled to ensure that the nozzle roll expansion is effective in performing its design function of mechanical support for the nozzle prior to the application of the IDTB weld. The parameters of interest are tool insertion depth and the torque setting on the assembly tool.

Tool insertion depth, based on tooling setup height, was controlled so that the rolled region was contained within the RVCH penetration bore. The torque applied to the roll expander was controlled so that the desired amount of plastic deformation occurred. The torque limiter assembly was set and independently verified with a calibrated torque wrench prior to use.

As noted above, the roll expansion process was completed for CEDM Nozzle #46 and the two parameters of interest (tool insertion depth and applied torque) that could impact the susceptibility to PWSCC were validated to be within process specifications. Additionally, rotary peening was applied to remediate the tensile surface stresses in the roll expanded region. As a result, adequate measures were applied during the modification of Nozzle #46 with respect to PWSCC for the life of the repair.

2CAN012302 Page 5 of 29 Entergy submitted a relief request for one cycle of operation beginning after 2R28 (Reference 11). The NRC Safety Evaluation approving the one cycle relief request was issued on April 7, 2022 (ML22073A095). This relief request contains the analyses and justification through the remainder of the current renewed license (July 17, 2038). Entergy has determined that modification of CEDM Nozzle #46 utilizing the alternatives specified in this request will provide an acceptable level of quality and safety for the remainder of the current renewed license. Relief is requested in accordance with 10 CFR 50.55a(z)(1).

5. PROPOSED ALTERNATIVE AND BASIS FOR USE 5.1 Welding Requirements The half nozzle repair on CEDM Nozzle #46 was performed using the ambient temperature temper bead process of Code Case N-638-7. Paragraph 2(b) of the Code Case permitted use of welding procedures qualified in accordance with previous Code Case revisions.

Accordingly, the welding procedure used on Nozzle #46 was qualified in accordance with N-638-4 (an earlier revision). Code Case N-638-4, paragraph 2.1(a) states:

The materials shall be post-weld heat treated to at least the time and temperature that was applied to the materials being welded.

Post-weld heat treatment (PWHT) can slightly degrade the fracture (notch) toughness of low alloy steels. Therefore, it is both reasonable and conservative to perform a simulated PWHT of test samples that will be used to evaluate base materials that have received PWHT during fabrication and placed into reactor service. However, it is not conservative to perform a simulated PWHT of welding qualification test plate material that will be compared to the temper bead heat affected zone (HAZ) for acceptance.

The temper bead weld procedure qualification is required to demonstrate that the Charpy V-notch test results from the weld HAZ are no less than the Charpy V-notch test results for the unaffected base material. Electric Power Research Institute (EPRI) Report 1025169, Section 3.0 (Reference 5) documents that simulated PWHT on procedure qualification test plates degrades the notch toughness of the test plate increasing the contrast between the impact properties of the base material test plate and the temper bead weld HAZ. In other words, the simulated PWHT makes passing the impact testing requirements of the temper bead procedure qualification less difficult. Therefore, simulated PWHT on the temper bead test coupon does not provide conservative results when the simulated PWHT time exceeds the actual PWHT time applied to the component during construction.

The RVCH material at ANO-2 had at least 50 hours5.787037e-4 days 0.0139 hours 8.267196e-5 weeks 1.9025e-5 months of PWHT but the weld procedure qualification test plate had 30 hours3.472222e-4 days 0.00833 hours 4.960317e-5 weeks 1.1415e-5 months of simulated PWHT. This condition did not comply with Code Case N-638-4, paragraph 2.1(a) which required simulated PWHT on the temper bead qualification test plate to be equivalent to or exceed the total aggregate time applied to the component to be welded. There is no maximum limit on the simulated PWHT time.

2CAN012302 Page 6 of 29 The simulated PWHT requirement of Code Case N-638 was recognized by the ASME Code Committee as non-conservative and was changed in Revision 7. Code Case N-638-7, paragraph 2.1(a) states that simulated PWHT of the test assembly is neither required nor prohibited. However, if used, the simulated PWHT shall not exceed the time or temperature already applied to the base material to be welded. The welding procedure used to implement the half nozzle repair on CEDM Nozzle #46 complies with this requirement.

Code Case N-638-7 was conditionally approved by the NRC in RG 1.147, Revision 19 at the time of implementation. The NRC condition, was unrelated to simulated PWHT, and stated:

Demonstration of ultrasonic examination of the repaired volume is required using representative samples that contain construction-type flaws. Therefore, the enhanced and more conservative simulated PWHT requirements in Code Case N-638-7 have also been approved by the NRC. The NRC condition that was applied to Code Case N-638-7 was incorporated into subsequent versions of the Case; therefore, the most recent issuance of RG 1.147 (Revision 20, issued in December 2021) lists Code Case N-638-10 as an unconditionally acceptable Section XI Code Case in Table 1.

In summary, ambient temperature temper bead welding was performed on CEDM Nozzle #46 in accordance with Code Case N-638-7 while the welding procedure was qualified in accordance with Code Case N-638-4. The qualified welding procedure did not comply with the simulated PWHT requirements of Revision 4 of the Code Case but did comply with the enhanced and more conservative simulated PWHT requirements in Revision 7 (i.e., N-638-7).

Therefore, Entergy requests approval to apply the simulated PWHT requirements of Code Case N-638-7, paragraph 2.1(a) when using the temper bead welding procedure on CEDM Nozzle #46.

Code Case N-638-7, paragraph 1(g) states:

Peening may be used, except on the initial and final layers.

Rotary peening was performed on the final layer to provide further assurance of the modified configuration being resistant to PWSCC. However, peening on the final layer of a temper bead weld is prohibited by ASME Code Case N-638-7, paragraph 1(g). This prohibition refers to the high cold-work peening that is traditionally used for configuration distortion control during welding, as was interpreted by ASME Xl-1-13-19 for Code Case N-606-1.

This is not considered applicable to the rotary peening process, which is highly controlled, uniform, and only influences a shallow surface layer (approximately 10 mils at the HAZ and 20 mils at the base metal). The uniform compressive stress layer created by the rotary peening process does not inhibit subsequent NDE. Furthermore, this residual compressive stress layer has been shown to greatly reduce PWSCC initiation. Recognizing these benefits, the ASME Code Committee revised Code Case N-638 (i.e., N-638-8) to allow use of peening processes designed to reduce residual surface tensile stresses on the final layer or surface of the weld.

2CAN012302 Page 7 of 29 Upon completion of peening, visual and surface examinations were performed on the peened surface. However, while the peening operation provides increased resistance to PWSCC initiation, the inspection frequency of ISI examinations on CEDM Nozzle #46 will comply with that specified in Item B4.20 of Code Case N-729-6 as approved by the NRC in 10 CFR 50.55a(g)(6)(ii)(D).

ASME Code Section III, Nonmandatory Appendix W, W-2140, clearly describes the beneficial nature of compressive stresses for the mitigation of stress corrosion cracking (SCC) susceptibility. It states that shot peening, as a form of stress improvement, can be used to place the inside diameter of piping in a compressive residual stress state to resist SCC. Extensive laboratory testing performed as part of MRP-61, "An Assessment of the Control Rod Drive Mechanism (CRDM) Alloy 600 Reactor Vessel Head Penetration PWSCC Remedial Techniques," indicates that shot peening successfully inhibits PWSCC initiation.

With rotary peening, the shot is captured in a flap and regularly spaced such that it uniformly imparts compressive stresses on metal surfaces.

Therefore, Entergy requests relief from Code Case N-638-7, paragraph 1(g).

5.2 IDTB Modification Acceptance Examinations ASME Section Ill, 1992 Edition, NB-5245, specifies progressive surface examination of partial penetration welds. The Construction Code requirement for progressive surface examination, in lieu of volumetric examination, was used because volumetric examination is not practical for the conventional partial penetration weld configurations. Therefore, the following combination of UT and PT examinations were performed.

The modified Vessel Head Penetration (VHP) weld is suitable for UT examination and the weld is accessible from both the top and bottom sides (Refer to Figure 4 through Figure 8).

UT volumetric examination of the modified configuration was performed as specified in ASME Code Case N-638-7, 4(a)(2) and 4(a)(4). RG 1.147, Revision 19, conditionally approved Code Case N-638-7 with the condition that UT volumetric examinations be demonstrated using representative samples which contain construction type flaws. See Section 7.1 for details. The acceptance criteria of NB-5330 of the 1992 Edition of the ASME Section Ill Code apply to all flaws identified within the examined volume.

The UT examination system is capable of scanning from cylindrical surfaces with inside diameters of approximately 2.82-inch. The scanning was performed using a 0° L-wave transducer, 45° L-wave transducers in two opposed axial directions, and 70° L-wave transducers in two opposed axial directions as well as 45° L-wave transducers in two opposed circumferential directions. The weld received 100% examination coverage.

Additionally, the low alloy steel extending to 0.25-inch beneath the weld into the low alloy steel base material (see Figure 3) was examined using the 0° L-wave transducer searching for evidence of under bead cracking and lack of fusion in the HAZ. These

2CAN012302 Page 8 of 29 examinations satisfy ASME Section III, NB-5330 requirements. The repair volume was extended to include 1-inch of Alloy 600 nozzle material above the weld and 1-inch of Alloy 690 material below the weld. UT examination coverage is as shown in Figure 4 through Figure 8 of this submittal.

In addition to the UT examinations, a surface PT examination was performed on the entire weld as shown in Figure 3. The final examination of the new weld and immediate surrounding region was sufficient to verify that defects have not been induced in the ferritic low alloy steel RVCH base material, due to welding, to the extent practical. The acceptance criteria of NB-5350 in ASME Section III, 1992 Edition were applicable.

The combination of performing PT and UT examinations depicted in Figure 3 during the IDTB repair provided assurance of structural integrity. Thus, Entergy requests relief from the progressive surface examination requirements specified in NB-5245.

5.3 Triple Point Anomaly ASME Section Ill, NB-5330(b) states:

Indications characterized as cracks, lack of fusion, or incomplete penetration are unacceptable regardless of length.

An artifact of ambient temperature temper bead welding is an anomaly in the weld at the triple point. There are two triple points in the modification. The upper triple point is the point in the repair weld where the low alloy steel RVCH base material, the Alloy 600 nozzle, and the Alloy 52M weld intersect. The lower triple point is the point in the repair weld where the low alloy steel RVCH base material, the Alloy 690 replacement nozzle, and the Alloy 52M weld intersect. The locations of the upper and lower triple points for the VHP modification are shown in Figure 2.

The anomaly consists of an irregularly shaped very small void. Mock-up testing has verified that the anomalies are common and do not exceed 0.10-inches in through-wall extent and are assumed to exist, for purposes of analysis, around the entire bore circumference at the triple point location.

Linear elastic fracture mechanics (LEFM) and limit load Life of Repair analyses (Reference 6) were performed for this repair considering flaws at the weld anomaly triple point locations. The analyses resulted in acceptable crack growth for the life of the repair, from the time of repair to the end of 60 year plant operating life, for a total of 17 years. The process for the Life of Repair analyses was as follows:

1. The initial flaw size for the postulated flaws in the triple point anomaly analysis was 0.100-inches. Crack growth analysis determined the future flaw size and concluded that it is acceptable for the stated life.

2CAN012302 Page 9 of 29

2. A fracture mechanics analysis was performed for the design configuration to provide justification, in accordance with ASME Section XI, for operating with the postulated triple point anomaly. The anomaly was modeled as a 0.100-inch deep crack-like defect, initiating at the triple point locations, considering the most susceptible material for propagation. Postulated flaws could be oriented within the anomaly such that there are three possible flaw propagation paths, as discussed in Items 3 and 4 below.

3. Circumferential and Axial Flaws: Flaw propagation was across the nozzle wall thickness from the outside diameter to the inside diameter of the nozzle housing for the upper and lower triple points.

a. The shortest paths were through the nozzle thickness at the upper and lower triple points (see Figure 2). By using a fatigue crack growth rate of twice that of the rate of Alloy 600 material to bound the Alloy 600/690 nozzle and Alloy 52M weld materials either in-air (for upper triple point flaws) or exposed to the reactor water environment (lower triple point flaws), it was ensured that all potential paths through the HAZ between the new repair weld and the Alloy 600 nozzle material was bounded.

b. For completeness, two types of flaws were postulated at the outside surface of the nozzle IDTB repair weld. A 360-degree continuous circumferential flaw, lying in a horizontal plane, was considered to be a conservative representation of crack-like defects that would exist in the weld triple point anomaly. This flaw was subjected to axial stresses in the nozzle. An axially oriented semi-circular outside surface flaw was also considered since it would lie in a plane normal to the higher circumferential stresses. Both of these flaws would propagate toward the inside surface of the nozzle.

4. Cylindrical Flaw: Flaw propagation extended down from the upper triple point or up from the lower triple point along the outside surface of the repair weld between the upper and lower triple points.

a. A cylindrically oriented flaw was postulated to lie along this interface, subjected to radial stresses with respect to the nozzle. This flaw could propagate through either the new Alloy 52M weld material or the low alloy steel RVCH base material.

5. The results of the LEFM and limit load analysis have demonstrated that a 0.100-inch weld anomaly is acceptable for life of repair, which is 17-years of operation following the VHP nozzle inside diameter temper bead weld repair. Acceptable design margins were demonstrated for all flaw propagation paths considered in the analysis. For the low alloy steel RVCH base material, the minimum fracture toughness margin has been shown to be greater than the required margin of 10 (3.16) for normal/upset/test conditions where pressure exceeds 20% of the design pressure, and 2 (1.41) for emergency/faulted conditions and normal/upset/test conditions where pressurization does not exceed 20%

of the design pressure and during which the minimum temperature is not less than

2CAN012302 Page 10 of 29 Reference Temperature for Nil Ductility Transition (RTNDT) per ASME Section XI, IWB-3613. A limit load analysis was also performed considering the ductile Alloy 600/Alloy 690 materials along flaw propagation path lines. This analysis showed a limit load margin greater than the required margin per ASME Section XI, IWB-3642.

For qualification of the IWB-3613 criteria, the analysis credits the following analytical limitations after IDTB repair of CEDM Nozzle #46 (in recognition of the LTOP lift setting)*:

a. The minimum fluid temperature for performing [

]

b. The maximum [ ] transient pressure when the fluid temperature is less or equal to [ ] is [ ]

c. The maximum [ ] transient pressure when the fluid temperature is less or equal to [ ] is [ ]

(*) Note that, per Section 5.2.2.4 of Reference [ ], the low temperature overpressure protection (LTOP) lift setting is limited to 430 psig for reactor coolant fluid temperature less or equal to 220°F and therefore, [

] operations are protected from exceeding this pressure at the [ ]

temperatures identified in the analysis limitations above.

6. Since the postulated outside diameter flaw in the weld anomaly at the upper triple point is not exposed to the primary coolant and the air environment is benign for the materials at the triple point, the time-dependent crack growth rates from PWSCC are not applicable. [

]

7. [

] satisfying the ASME Section XI criteria.

Entergy requests relief from the acceptance criteria specified in NB-5330(b) of ASME Section III to permit anomalies, as described herein, at the triple point area to remain in service.

5.4 Flaw Characterization and Successive Exams - RVCH Original J-Groove Weld The assumptions of IWB-3600 of ASME Section XI are that cracks are fully characterized in accordance with IWB-3420 in order to compare the calculated parameters to the acceptable parameters addressed in IWB-3500. There are no qualified UT examination techniques for examining the original nozzle-to-RVCH J-groove welds. Therefore, since it is impractical to characterize the flaw geometry that may exist therein, it was conservatively assumed that

2CAN012302 Page 11 of 29 the "as-left" condition of the remaining J-groove weld includes flaws extending through the entire Alloy 82/Alloy 182 J-groove weld and buttering. It was further postulated that the dominant hoop stresses in the J-groove weld would create a situation where the preferential direction for cracking would be radial. A radial crack in the Alloy 82/Alloy 182 weld would propagate by PWSCC through the weld and buttering to the interface with the low alloy steel RVCH material. Any growth of the postulated "as-left" flaw into the low alloy steel would be by fatigue crack growth under cyclic loading conditions.

Based on a combination of linear elastic and elastic-plastic fracture mechanics the "Life of Repair" analyses (Reference 7) resulted in a fatigue crack growth life for the "as-left" J-groove flaw of at least 17 years after the IDTB repair recognizing the following analytical limitations ensured by the LTOP lift setting*:

1. The minimum fluid temperature for performing [

]

2. The maximum [ ] transient pressure when the fluid temperature is less or equal to [ ] is [ ]

3. The maximum [ ] transient pressure when the fluid temperature is less or equal to [ ] is [ ]

(*) Note that, per Section 5.2.2.4 of Reference [12], the low temperature overpressure protection (LTOP) lift setting is limited to 430 psig for reactor coolant fluid temperature less or equal to 220°F and therefore, [Heatup and Cooldown] operations are protected from exceeding this pressure at the [low] temperatures identified in the analysis limitations above.

The process for the Life of Repair analyses was as follows:

2CAN012302 Page 12 of 29 Relief is requested from flaw characterization specified in IWB-3420.

In addition, the potential for debris from a cracked J-groove weld remnant was considered.

Radial cracks (relative to the nozzle) were postulated to occur in the J-groove weld due to the dominance of higher hoop stresses relative to axial stresses. The possibility of transverse cracks occurring that could subsequently intersect the radial cracks is considered remote as there are minimal driving forces for cracks in the transverse direction. The radial cracks would relieve the driving forces for any potential transverse cracks. There are no known service conditions that could drive radial cracks and transverse cracks to intersect to produce a loose part. There is extensive operating experience with remnant J-groove welds for which there are no known cases of debris generation (loose parts) due to PWSCC of the remnant J-groove weld. Therefore, cracking of the J-groove weld resulting in debris (loose parts) is not expected.

5.5 lnservice Inspection (ISI) of VHPs Code Case N-729-6 as approved by the NRC in 10 CFR 50.55a specifies requirements for performing ISI examinations of RVCHs with nozzles having partial penetration welds. Code Case N-729-6 Table 1, Item B4.20, permits either volumetric or surface examination.

Item B4.20 examination requirements are specified in Figure 2 of Code Case N-729-6.

ISI examination of CEDM Nozzle #46 will be performed using a volumetric examination method. In lieu of the volumetric examination region that extends 1.5-inch above and 1.5-inch below the J-groove weld shown in Figure 2 of Case N-729-6, an alternative examination region will be interrogated for the repair weld. The examination volume will extend up to the outer surface of the head (greater than 1.5-inch above the repair weld),

including the rotary peened surfaces (including the roll transition region), and 1-inch below the repair weld as shown in Figure 9. Examination coverage below the weld will be less than the 1.5-inch requirement due to geometric limitations; however, the coverage will extend a minimum of 1-inch below the weld and will obtain the maximum volume practical.

Examination coverage of 1-inch below the repair weld is considered sufficient due to the following:

2CAN012302 Page 13 of 29 The replacement nozzle material (Alloy 690) is resistant to PWSCC The replacement nozzle is non-pressure boundary material The new pressure boundary weld (Alloy 52M) is resistant to PWSCC The repair performed during 2R28 modified the examination volume depicted in Figure 2 of Code Case N-729-6. Figure 9 of this submittal establishes the examination volume for ISI examinations. The examination volume also includes the rotary peened surfaces.

Successive examinations required by Code Case N-729-6 will be performed on CEDM Nozzle #46 during each refueling outage.

All other ANO-2 RVCH CEDM and ICI nozzles will continue to be examined in accordance with Code Case N-729-6 as modified by 10 CFR 50.55a(g)(6)(ii)(D) and other NRC approved alternatives.

Therefore, future ISI examinations will comply with Code Case N-729-6 as modified by 10 CFR 50.55a(g)(6)(ii)(D) and as depicted in Figure 9.

5.6 General Corrosion Impact on Exposed Low Alloy Steel The IDTB nozzle modification left a small portion of low alloy steel in the RVCH exposed to primary coolant. An evaluation was performed for the potential corrosion concerns at the RVCH low alloy steel wetted surface. Galvanic corrosion, hydrogen embrittlement, SCC, and crevice corrosion are not expected to be a concern for the exposed low alloy steel base metal. General corrosion of the exposed low alloy steel base metal will occur in the area between the IDTB weld and the original J-groove weld. Due to the depletion of oxygen, tight geometry, and lack of Primary Coolant System (PCS) flow at the exposed low alloy steel, general corrosion will significantly decrease after a period of time. As the surface of the low alloy steel passivates, the long-term corrosion rate is expected to be negligible. However, a conservative, sustained, corrosion rate was applied and the resultant increase in bore diameter was considered in the reinforcement calculation (per NB-3330) as part of the ASME Section III analysis. The corrosion evaluation (Reference 8) and the ASME Section III analysis (Reference 10) are attached to this submittal.

Galvanic Corrosion The results of the NRCs boric acid corrosion program have shown that the galvanic difference between SA-533 Grade B, Alloy 600, and Type 308 stainless steel (nominal chemistry of RVCH cladding) is not significant enough to consider galvanic corrosion as a strong contributor to the overall boric acid corrosion process (NUREG-1823). Therefore, it was judged that galvanic corrosion between the exposed RVCH low alloy steel, Alloy 600, Alloy 690, or their weld metals is not a concern for this repair configuration. This is supported by studies documented in EPRI Report 1000975 in which low alloy steel specimens were coupled and uncoupled to stainless steel exposed to a borated water environment at various temperatures. The corrosion rates for the coupled and uncoupled

2CAN012302 Page 14 of 29 conditions were determined to be similar. Additionally, galvanic corrosion of carbon steel coupled to stainless steel in boric acid solution in the absence of oxygen should be quite low. The results of this study are also applicable to nickel-based alloys as austenitic stainless steels have approximately the same corrosion potential as nickel-based alloys such as Alloy 600 and Alloy 690.

Hydrogen Embrittlement Hydrogen embrittlement occurs when a material property is degraded due to the presence of hydrogen. This type of damage usually occurs in combination with an acting stress. The hydrogen concentration in the RVCH will be greatest at the exposed surface and decreases across the thickness of the RVCH to the trace concentration of hydrogen in the low alloy steel. Hydrogen concentrations in the reactor coolant system are deemed insufficient to induce hydrogen cracking in the low alloy steel of the RVCH. Therefore, it was determined that hydrogen embrittlement is not a concern for the exposed RVCH low alloy steel in the repaired configuration. This conclusion is supported by many cases of low alloy steels being exposed to primary coolant without any observed cracking due to hydrogen embrittlement.

Stress Corrosion Cracking There is extensive Pressurized Water Reactor (PWR) and Boiling Water Reactor (BWR) operating experience related to low alloy steels being exposed to the reactor coolant environment. This operating experience has not identified any known occurrence of stress corrosion cracking of the low alloy steel of RVCHs. Likewise, there are no existing ASME Section XI Code rules or NRC regulations addressing this issue in RVCH low alloy steels in PWR reactor coolant environment. Therefore, it has been determined that stress corrosion cracking of the low alloy steel of the RVCH is not a concern for this repair configuration.

Crevice Corrosion The geometry of the gap between the RVCH and replacement nozzle could create conditions for crevice corrosion. However, operating experience for PWRs shows that crevice corrosion of low alloy steels associated with these half nozzle repairs is not a problem in PWR systems due to expected low oxygen contents. Furthermore, the surface of the low alloy steel material will passivate with time, decreasing the rate of corrosion within the crevice. Therefore, it was determined that crevice corrosion of the low alloy is not a concern.

General Corrosion Corrosion of the exposed low alloy steel is not expected to be a concern based on existing operating experience. The surface of the low alloy steel material will passivate with time, decreasing the rate of general corrosion. As corrosion products fill this gap, they will isolate the low alloy steel surface from the reactor coolant system, thereby, impeding the transport of oxygen which is necessary to sustain continued general corrosion. Due to the depleted

2CAN012302 Page 15 of 29 oxygen, passivated surface, tight geometry, and lack of appreciable reactor coolant flow at the exposed low alloy steel, general corrosion will decrease significantly after a period of time.

5.7 Conclusions The IDTB repair to RVCH CEDM Nozzle #46 produced an effective repair that restored and maintained the pressure boundary integrity of the VHP. Other IDTB modifications have been performed successfully (see Section 8) and were in service for several years without any known degradation [e.g., Shearon Harris (2012, 2013, 2015, 2016 and 2018) and Palisades (2004, 2018, and 2020)]. This alternative provides improved structural integrity and reduced likelihood of leakage for the primary system. Detailed finite element based Life of Repair analyses (Reference 6) resulted in a crack growth life for the triple point anomaly flaw of at least 17 years after the repair (in 2038 after 60 years of plant operation).

Likewise, "Life of Repair" analyses performed on the "as-left" J-groove flaw (Reference 7) resulted in a fatigue crack growth life of at least 17 years after the repair (in 2038 after 60 years of plant operation). Corrosion of the exposed low alloy steel base material is not a concern due to lack of oxygen, tight geometry, and lack of reactor coolant system flow in the exposed region. The analyses and evaluations discussed herein justify continued use of the nozzle repair for the current operating life of the plant. Accordingly, the use of the alternative provides an acceptable level of quality and safety in accordance with 10 CFR 50.55a(z)(1).

6. DURATION OF PROPOSED ALTERNATIVE The overall acceptable life of the repair is based on the most limiting life predicted by three evaluations: the weld anomaly analysis (see Section 5.3), the as-left J-groove weld analysis (see Section 5.4), and the PWSCC evaluation of the original Alloy 600 nozzle. A PWSCC evaluation of the IDTB repair is included in the (Life) Assessment Summary (Reference 9).

For the weld anomaly and as-left J-groove weld analyses, the demonstrated 17-year life starts at the time of the repair. The compressive stress imparted by the rotary peening process is expected to mitigate the residual tensile surface stresses in the Alloy 600 CEDM nozzle material at the roll expanded transition area and adjacent to the Alloy 52M IDTB weld. Therefore, the PWSCC evaluation concluded that due to the compressive stresses achieved by rotary peening, PWSCC initiation is not expected during the 17-year life of the repair.

The duration of the proposed alternative is until the end of the current renewed license (July 17, 2038).

2CAN012302 Page 16 of 29

7. ADDITIONAL INFORMATION 7.1 VHP Weld Qualification Mockup UT Acceptance Volumetric examination was required by Code Case N-638-7. NRC RG 1.147, Revision 19 imposed a condition for this code case that required UT demonstration on representative samples which contained construction type flaws. Framatome, in support of many similar modifications, performed demonstrations using IDTB weld repair mockups since VHP modifications at Oconee Nuclear Station in 2001. The most recent procedure demonstration took place during the 2010 Davis Besse control rod drive mechanism (CRDM) repair campaign which included review of recorded automated data showing UT responses obtained from an IDTB weld mockup for the half-nozzle repair. This is the same mockup used for the procedure demonstration for Shearon Harris VHP nozzle modifications listed in Section 8.

To satisfy this requirement, an IDTB weld half-nozzle repair mockup containing reflectors to simulate construction type flaws applicable to this weld process was used. It contained a series of electrical-discharge machining (EDM) notches at the triple point to simulate the triple point anomaly at various depths into the nozzle wall and cracking at the IDTB weld to low alloy steel interface. It also contained flat bottom holes drilled from the mockup outside diameter so that the hole face was normal to the nozzle surface to simulate under-bead cracking, and lack of bond, or lack of fusion throughout the weld volume. The examination procedure demonstrated the ability to detect a linear weld fabrication triple point anomaly extending 0.05-inch and greater into the weld.

A Nickle-Chromium-Iron (NiCrFe) alloy calibration block was used and contained a series of EDM notches at nominal depths of 10%, 25%, 50%, and 75% deep from both inside diameter and outside diameter surfaces in both the axial and circumferential orientation.

The block also contained 1/4T, 1/2T, and 3/4T deep end-drilled holes and side-drilled holes that were used for calibration.

During the repair at ANO-2, the site crew performed training on mockups for each of their respective specialties, i.e., machinists train on machining mockups, welders train on welding mockups, and NDE personnel train on NDE mockups. Prior to examination of the repair weld at ANO-2, UT personnel practiced using the data files from the demonstration described above.

8. PRECEDENTS

1. Nuclear Management Company (NMC) letter to the NRC, "Request for Relief from ASME Section XI Code Requirements for Repair of Reactor Pressure Vessel Head Penetrations," dated October 11, 2005, ML052870321.

2CAN012302 Page 17 of 29

2. FirstEnergy Nuclear Operating Company (FENOC) letter to the NRC, "10 CFR 50.55a Request for Alternate Repair Methods for Reactor Pressure Vessel Head Penetration Nozzles," dated April 1, 2010, ML100960276.

3. Constellation Energy letter to the NRC, "Relief Request for Modifications to Pressurizer Heater Sleeves and Lower Level Nozzle Penetrations (RR-PZR-01),"

dated January 31, 2011, ML110340059.

4. Progress Energy letter to the NRC, "Relief Request I3R-09 Reactor Vessel Closure Head Nozzles Inservice Inspection Program - Third Interval," dated May 3, 2012, ML12131A663.

5. Duke Energy letter to the NRC, "Relief Request I3R-11 Reactor Vessel Closure Head Nozzles Inservice Inspection Program - Third Interval," dated May 22, 2013, ML13143A167.

6. Duke Energy letter to the NRC, "Relief Request I3R-13 Reactor Vessel Closure Head Nozzle 37, Inservice Inspection Program - Third Ten-Year Interval," dated November 22, 2013, ML13329A354.

7. Duke Energy letter to the NRC, "Relief Request I3R-15, Reactor Vessel Closure Head Nozzle Repair Technique, Inservice Inspection Program - Third Ten-Year Interval,"

dated April 2, 2015, ML15092A236.

8. Duke Energy letter to the NRC, "Relief Request I3R-16, Reactor Vessel Closure Head Nozzle Repair Technique, Inservice Inspection Program, Third Ten-Year Interval,"

dated October 19, 2016, ML16294A218.

9. Duke Energy letter to the NRC, "Relief Request I3R-18, Reactor Vessel Closure Head Nozzle Repair Technique, Inservice Inspection Program, Fourth Ten-Year Interval,"

dated April 18, 2018, ML18108A094.

10. Entergy letter to the NRC, "Relief Request Number RR 5-7 Proposed Alternative to ASME Section XI Code Requirements for Repair of Reactor Pressure Vessel Head Penetrations," dated November 26, 2018, ML18330A142.

11. Entergy letter to the NRC, "Relief Request Number RR 5-8 Proposed Alternative to ASME Section XI Code Requirements for Repair of Reactor Pressure Vessel Head Penetrations," dated September 23, 2020, ML20267A387.

12. Florida Power & Light Company letter to the NRC, "Unit 1 Relief Request 21 and Unit 2 Relief Request 31 Request for Additional Information Response," dated April 14, 2003, ML031060268.

2CAN012302 Page 18 of 29

9. REFERENCES 1 ASME Code Case N-638-7, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique,Section XI, Division 1.

2 NRC Regulatory Guide 1.147, Revision 19, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, ML19128A244.

3 ASME Code Case N-729-6, Alternative Examination Requirements for PWR Reactor Vessel Upper Heads With Nozzles Having Pressure-Retaining Partial-Penetration Welds,Section XI, Division 1.

4 Entergy letter to the NRC, Request for Alternative to 10 CFR 50.55a(g)(6)(ii)(D)

Examination Requirements - Relief Request ANO2-ISI-022, dated November 24, 2020, ML20329A202, (2CAN112001).

5 EPRI Report 1025169, Welding and Repair Technology Center: Welding and Repair Technical Issues in ASME Section XI.

6 [ ] Document Number 32-9352239-001.

7 [

] Document Number 32-9352384-001.

8 [

] Document Number 51-9338948-001.

9 [ ] Document Number 51-9352242-000.

10 [

] Document Number 32-9348826-002.

11 Relief Request ANO2-RR-21-002, Half Nozzle Repair of Reactor Vessel Closure Head Penetration #46, November 5, 2021, ML21309A007, (2CAN112103).

12 Arkansas Nuclear One, Unit 2, Safety Analysis Report Amendment 30 (Redacted),

April 2022, ML22124A153, (2CAN042201).

13 Response to Request for Additional Information Concerning Relief Request N-638-7-002 Support the Repair of the Reactor Vessel Closure Head Penetration

46, November 7, 2021, ML21312A017, (2CAN112105).

2CAN012302 Page 19 of 29 Figure 12 Nozzle Machining

2CAN012302 Page 20 of 29 Figure 13 Nozzle Weld

2CAN012302 Page 21 of 29 Figure 14 Nozzle Examination Pre - Weld PT k-l-o-p Post - Weld PT m-n-o-p-q Post - Weld UT a-b-c-d-e-f-g-h-j-a NOTE: For Post - Weld PT, extent of examination above and below the weld was 1-inch for Nozzle #46. In addition, the examination included a minimum of 0.81-inch above the rolled transition area.

2CAN012302 Page 22 of 29 Figure 15 Nozzle 0° and 45°L UT Beam Coverage Looking Clockwise and Counter-Clockwise

2CAN012302 Page 23 of 29 Figure 16 Nozzle 45°L UT Beam Coverage Looking Down

2CAN012302 Page 24 of 29 Figure 17 Nozzle 45°L UT Beam Coverage Looking Up

2CAN012302 Page 25 of 29 Figure 18: Nozzle 70°L UT Beam Coverage Looking Down

2CAN012302 Page 26 of 29 Figure 19: Nozzle 70°L UT Beam Coverage Looking Up

2CAN012302 Page 27 of 29 Figure 20: Nozzle ISI UT Examination UT a-b-c-d-a UT e-c (leak path)

Note: Extent of examination above the weld extends up to the outer surface of the head and below the weld is 1-inch for Nozzle #46.

2CAN012302 Page 28 of 29 Figure 21: Reactor Vessel Head Penetration Locations Notes:

3. Figure 10 shows the locations of the RVCH penetrations. There are 81 CEDM penetrations, eight In-core Instrument penetrations, and one Vent line.

4. CEDM Penetration #46 is highlighted.

2CAN012302 Page 29 of 29 Figure 22: Indication Location

ENCLOSURE 2, ATTACHMENT 1 2CAN012302

[ ]

Document Number 32-9357272-000 (NON-PROPRIETARY)

0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY CALCULATION

SUMMARY

SHEET (CSS)

Document No. 32 - 9357272 - 000 Safety Related: Yes No Title IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary PURPOSE AND

SUMMARY

OF RESULTS:

Purpose:

The purpose of this analysis is to perform a fracture mechanics evaluation of a postulated weld anomaly for the ANO-2 control element drive mechanism (CEDM) inner diameter temper bead (IDTB) repair weld at penetration No. 46. The analysis evaluates a postulated 0.100 inch weld anomaly characterized as a linear defect extending into the weld in any direction from the triple point locations. Flaw growth is calculated for several potential propagation paths from the time of IDTB weld installation in 2021 through 60 years of operation in 2038, for a total of 17 years. Flaw acceptance is based on the ASME B&PV Code, 2007 Edition with 2008 Addenda,Section XI, IWB-3613 for acceptance criteria based on applied stress intensity factor and IWB-3642 for limit load.

Summary of Results:

The results of the analysis demonstrate that a postulated 0.100 inch weld anomaly in the CEDM IDTB weld is acceptable from the time of IDTB weld installation in 2021 through 60 years of operation in 2038, for a total of 17 years. As summarized in Section 7.0, the minimum fracture toughness margins for flaw propagation are acceptable. The limit load analysis performed considering the ductile weld repair material along the horizontal flaw propagation paths shows that for the postulated circumferential and axial flaws, the minimum margin on allowable stress is acceptable. Fracture toughness margins have also been demonstrated for the postulated cylindrical flaws. Also, for the cylindrical flaws it is shown that the applied shear stress for the remaining ligament is less than the allowable shear stress per NB-3227.2.

Analysis Limitations for IDTB repair:

x The minimum fluid temperature for performing [ ]

x The maximum [ ] transient pressure when the fluid temperature is less or equal to [

]

x The maximum [ ] transient pressure when the fluid temperature is less or equal to [

]

Note that per Reference [14], the low temperature overpressure protection (LTOP) lift setting is limited to 430 psig and therefore, [ ] operations are protected from exceeding this pressure at the [ ] temperatures identified in the limitations above.

Proprietary information in the document is identified by bold brackets ([ ]). The proprietary version of this document is 32-9352239-001.

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, THE DOCUMENT CONTAINS AP 0402-01 requires that justification be provided.

ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE CODE/VERSION/REV CODE/VERSION/REV Yes AREVA CGC 6.0 No Page 1 of 37

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 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 P/R/A/M Name and Title and Pages/Sections (printed or typed) Signature LP/LR Date Prepared/Reviewed/Approved Jennifer Nelson LP See All Principal Engineer Signature Samer Mahmoud LR See All Advisory Engineer Signature Ryan Hosler A See All Supervisory Engineer Signature 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 Title (printed or typed) (printed or typed) Signature Date Comments N/A N/A N/A N/A N/A Page 2

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Record of Revision Revision Pages/Sections/Paragraphs No. Changed Brief Description / Change Authorization 000 All Original Document. The proprietary version of this document is 32-9352239-001.

Page 3

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Table of Contents Page SIGNATURE BLOCK ................................................................................................................................ 2 RECORD OF REVISION .......................................................................................................................... 3 LIST OF TABLES ..................................................................................................................................... 6 LIST OF FIGURES ................................................................................................................................... 7 1.0 PURPOSE ..................................................................................................................................... 8 2.0 METHODOLOGY .......................................................................................................................... 8 2.1 Crack Growth Calculations ................................................................................................................ 8 2.1.1 Postulated Flaws................................................................................................................. 8 2.1.2 Stress Intensity Factor (SIF) Solution ............................................................................... 10 2.1.3 Fatigue Crack Growth Laws ............................................................................................. 11 2.1.4 PWSCC Crack Growth in Alloy 52M ................................................................................. 14 2.1.5 General Corrosion in Low Alloy Steel ............................................................................... 14 2.2 Flaw Acceptance Criteria ................................................................................................................ 14 2.2.1 Axial and Circumferential Flaw Acceptance Criteria......................................................... 14 2.2.2 Cylindrical Flaw Criteria ....................................................................................................14 3.0 ASSUMPTIONS .......................................................................................................................... 16 3.1 Unverified Assumptions................................................................................................................... 16 3.2 Justified Assumptions...................................................................................................................... 16 3.3 Modeling Simplifications .................................................................................................................. 16 4.0 DESIGN INPUTS ........................................................................................................................ 17 4.1 Geometry ......................................................................................................................................... 17 4.2 Material ............................................................................................................................................ 18 4.2.1 Material Strength............................................................................................................... 18 4.2.2 Fracture Toughness .......................................................................................................... 18 4.3 Loads and Stresses......................................................................................................................... 19 4.3.1 Transient Stresses ............................................................................................................19 4.3.2 Weld Residual Stresses .................................................................................................... 20 4.3.3 External Loads .................................................................................................................. 20 4.3.4 Crack Face Pressure Loads ............................................................................................. 20 4.4 General Corrosion ........................................................................................................................... 20 5.0 COMPUTER USAGE .................................................................................................................. 21 5.1 Software .......................................................................................................................................... 21 5.2 Computer Files ................................................................................................................................ 21 Page 4

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 6.0 CALCULATIONS ......................................................................................................................... 22 6.1 OD Circumferential Flaw in Alloy 52 IDTB Weld ............................................................................. 22 6.1.1 Circumferential Flaw Growth ............................................................................................ 22 6.1.2 Circumferential Flaw Evaluation ....................................................................................... 23 6.2 OD Axial Flaw in Alloy 52 IDTB Weld ............................................................................................. 24 6.2.1 Axial Flaw Growth .............................................................................................................24 6.2.2 Axial Flaw Evaluation ........................................................................................................26 6.3 Cylindrical Flaw in Alloy 52 IDTB Weld and LAS RVCH ................................................................. 27 6.3.1 Cylindrical Flaw Growth .................................................................................................... 27 6.3.2 Cylindrical Flaw Evaluation .............................................................................................. 31 7.0

SUMMARY

OF RESULTS .......................................................................................................... 34

8.0 REFERENCES

............................................................................................................................ 35 APPENDIX A : VERIFICATION OF EXCEL MACRO KIEFF_EDGE .................................................... 36 Page 5

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary List of Tables Page Table 4-1: Path Geometry...................................................................................................................... 17 Table 4-2: Material Strength .................................................................................................................. 18 Table 4-3: Operating Transients and Cycles ......................................................................................... 19 Table 5-1: Computer Files ..................................................................................................................... 21 Table 6-1: Circumferential Flaw Growth Summary in Alloy 52 IDTB Weld ............................................ 22 Table 6-2: Circumferential Flaw C-5320 Limit Load Evaluation in Alloy 52 IDTB Weld ......................... 23 Table 6-3: Axial Flaw Growth Summary in Alloy 52 IDTB Weld ............................................................ 25 Table 6-4: Axial Flaw C-5410 Limit Load Evaluation in Alloy 52 IDTB Weld ......................................... 26 Table 6-5: Cylindrical Flaw Growth Summary for Final Year in Alloy 52 IDTB Weld, TOP .................... 27 Table 6-6: Cylindrical Flaw Growth Summary for Final Year in Alloy 52 IDTB Weld, BOT .................... 28 Table 6-7: Cylindrical Flaw Growth Summary for Final Year in LAS RVCH, TOP ................................. 29 Table 6-8: Cylindrical Flaw Growth Summary for Final Year in LAS RVCH, BOT ................................. 30 Table 6-9: LEFM Evaluation for Cylindrical Flaw in LAS RVCH ............................................................ 32 Table 6-10: Shear Stress Evaluation for Cylindrical Flaw in Alloy 52 IDTB Weld .................................. 33 Table 7-1: Summary of Results ............................................................................................................. 34 Page 6

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary List of Figures Page Figure 2-1: Crack Propagation Paths....................................................................................................... 9 Figure 2-2: OD, Partial Through-Wall, 360° Circumferential Flaw ......................................................... 10 Figure 2-3: OD, Partial Through-Wall, Semi-Elliptical Axial Flaw .......................................................... 10 Page 7

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 1.0 PURPOSE The purpose of this analysis is to perform a fracture mechanics evaluation of a postulated weld anomaly for the ANO-2 control element drive mechanism (CEDM) inner diameter temper bead (IDTB) repair weld at penetration No. 46. Per Reference [1], the analysis evaluates a postulated 0.100 inch weld anomaly characterized as a linear defect extending into the IDTB weld in any direction from the triple point locations. Flaw growth is calculated for several potential propagation paths from the time of IDTB weld installation in 2021 through 60 years of operation in 2038, for a total of 17 years. Flaw acceptance is based on the ASME B&PV Code, 2007 Edition with 2008 Addenda,Section XI, Reference [2], IWB-3613 for acceptance criteria based on applied stress intensity factor and IWB-3642 for limit load.

2.0 METHODOLOGY The methodology used for the linear elastic fracture mechanics (LEFM) and limit load analysis to evaluate a postulated 0.100 inch weld anomaly is summarized as follows. For the postulated flaw types described in Section 2.1.1, crack growth is calculated using the stress intensity factor solutions described in Section 2.1.2, fatigue crack growth laws described in Section 2.1.3, primary water stress corrosion cracking (PWSCC) crack growth described in Section 2.1.4 and general corrosion described in Section 2.1.5 to determine the final flaw size for the remainder of 60 year plant life. After the final flaw size is determined, the flaw is assessed to determine the safety margins and compliance with the flaw acceptance criteria outlined in Section 2.2.

2.1 Crack Growth Calculations 2.1.1 Postulated Flaws The analysis shall justify a postulated 0.100 inch weld anomaly characterized as a linear defect extending into the weld in any direction from the triple point locations. Therefore, anomalies are postulated at both the upper and lower triple point regions, which are called triple points since three materials intersect at these locations. The upper triple point is defined as the intersection of the reactor vessel closure head (RVCH) low alloy steel base material, the existing CEDM nozzle, and the Alloy 52M IDTB weld. The lower triple point is defined as the intersection of the RVCH low alloy steel base material, the Alloy 690 replacement CEDM nozzle, and the IDTB Alloy 52M weld.

Multiple flaw types are postulated to simulate various orientations (axial, circumferential and cylindrical) and propagation directions (horizontal and vertical) for which fatigue crack growth (FCG) is calculated. The horizontal and vertical flaw propagation directions are illustrated in Figure 2-1.

Horizontal Direction (Paths 1, 2 and 3 and Paths 7, 8 and 9):

Both circumferential and axial flaws are postulated at the outside surface of the new IDTB weld, which both propagate in the horizontal direction toward the inside surface of the new IDTB weld. These are the shortest paths through the component wall passing through the new Alloy 52M weld material at the upper and lower triple points.

A 360° continuous circumferential flaw in the horizontal plane is considered to be a conservative representation of crack-like defects that may exist in the weld anomaly. This flaw is subject to axial stresses in the weld. In addition, an axially oriented semi-circular outside surface flaw is also considered since it lies in a plane that is normal to the higher circumferential stresses. A flaw length to depth aspect ratio of [ ] is considered for the postulated axial flaw, which is considered sufficient given the initial flaw depth of 0.1 inches in comparison to the size of the IDTB weld (Section 3.2, Item 4).

Page 8

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Vertical Direction (Paths 4, 5 and 6 and Paths 10, 11 and 12):

Cylindrically oriented flaws are postulated along the interface between the weld and RVCH, which propagate vertically downward or upward between the two components from the top or bottom of the flaw tip. A continuous surface flaw is postulated to lie along the cylindrical interface between the two materials. This flaw, driven by radial stresses, may propagate along either the new Alloy 52M weld material or the SA-533, Gr. B RVCH material from either corner.

Figure 2-1: Crack Propagation Paths Page 9

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 2.1.2 Stress Intensity Factor (SIF) Solution Three flaw types are postulated for the weld anomaly analysis originating from the upper or lower triple points.

Circumferential and Axial Flaws For Paths 1, 2 and 3 and Paths 7, 8 and 9, both 360° circumferential and axial surface flaws at the OD of the IDTB weld are postulated. The solutions for both circumferential and axial flaws are available in the AREVACGC 6.0 code, which implements the Stress Intensity Factor (SIF) evaluation for these types of flaws using the weight function method, which is suitable for highly nonlinear stress distributions. AREVACGC 6.0 performs the fatigue crack growth calculations in the flaws located in upper triple point and the fatigue plus PWSCC crack growth calculations in the flaws located in lower triple point. Note that PWSCC is assessed for the lower triple point flaw since this location may be exposed to the reactor water environment. Weld residual stresses from Reference [3]

and transient stress distributions from Reference [4] are directly used to calculate the SIF using weight function method, with no polynomial fitting of the stress distribution required. The schematics for both the 360° circumferential and axial flaws postulated at the OD of the IDTB weld are illustrated in Figure 2-2 and Figure 2-3, respectively.

Figure 2-2: OD, Partial Through-Wall, 360° Circumferential Flaw Figure 2-3: OD, Partial Through-Wall, Semi-Elliptical Axial Flaw Page 10

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Cylindrical Flaw For the vertical paths (Paths 4, 5 and 6 and Paths 10, 11 and 12), a cylindrical flaw is postulated along the interface between the new IDTB repair weld and the RV head material. The potential for flaw propagation along this interface is likely if radial stresses are significant between the weld and head. This assessment utilizes a SIF solution for a continuous surface crack in a flat plate from Appendix A,Section XI of the ASME B&PV Code, 2007 Edition with 2008 Addenda (Reference [2]). Flat plate solutions are routinely used to evaluate flaws in cylindrical components such as the repair weld. The flat plate solution is inherently conservative for this application since the added constraint provided by the cylindrical structure reduces the crack opening displacements. Crack growth analysis is performed considering propagation through the Alloy 52 weld metal or the low alloy steel RVCH material. To facilitate the calculation of the SIF for the cylindrical flaw, a visual basic code, KIeff_edge is used, which is based on the theory in Appendix A,Section XI of the ASME B&PV Code (Reference [2]).

A third order polynomial fit is used to represent the weld residual and transient stress distributions over the flaw depth for evaluating the cylindrical flaws. Although the stress distributions can be highly nonlinear in general, the third order polynomial fit only needs to accurately represent the stress distribution for the distance between the crack mouth and crack depth (see Section XI, A-3200(b), Reference [2]). This short segment is only a small percentage of the overall weld depth; thus, the stress can be adequately represented with a third order polynomial fit as used in this analysis.

2.1.3 Fatigue Crack Growth Laws Flaw growth due to fatigue is characterized by the following equation:

= ( )

Where Co and n are constants that depend on the material and environmental conditions, 'KI is the range of applied VWUHVVLQWHQVLW\IDFWRULQWHUPVRINVL¥LQDQGGDG1LVWKHLQFUHPHQWDOIODZJURZWKLQ terms of inches/cycle. For the embedded weld anomaly considered in the present analysis at the upper triple point, it is appropriate to use crack growth rates for an air environment. For the embedded weld anomaly considered at the lower triple point, the crack growth rates for material exposed to light-water reactor environments are utilized if bounding.

Fatigue crack growth is also dependent on the ratio of the minimum to the maximum stress intensity factor, expressed as:

= /

SA-533 Grade B Low Alloy Steel Material (RVCH) in Air Environment From Article A-4300 of Section XI, 2007 Edition with 2008 Addenda (Reference [2]), the fatigue crack growth constants for flaws in an air environment are:

n = 3.07 Co = 1.99 x10-10 S S is a scaling parameter to account for the R ratio and is given by:

6 í5 íZKHUH5DQG'KI = Kmax í.min.

For R < 0, 'KI depends on the crack depth, a, and the flow stress, Vf. The flow stress is defined as:

Vf = 1/2(Vys + Vult), where Vys is the yield strength and Vult is the ultimate tensile strength.

Page 11

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary

)RUí5DQG.max í.min

Vf¥D6 DQG'KI = Kmax.

)RU5íDQG.max í.min

Vf¥D6 DQG'KI í5 .max/3.

For R < 0 and Kmax í.min >1.12 Vf¥D6 DQG'KI = Kmax í.min.

SA-533 Grade B Low Alloy Steel Material (RVCH) in Light Water Reactor Environments From Article A-4300, for material exposed to light-water reactor environments, the fatigue crack growth constants are:

'KI = Kmax í.min.

5

'KI < 17.74 n = 5.95 S = 1.0 C0 = 1.02 x 10íS

'KI

n = 1.95 S = 1.0 C0 = 1.01 x 10íS 0.25 < R < 0.65:

'KI > 5 >> 5í @0.25 n = 5.95 6 6í

C0 = 1.02 x 10íS

.I > 5 >> 5í @0.25 n = 1.95 S = 3.75R + 0.06 C0 = 1.01 x 10íS

5

.I < 12.04 n = 5.95 S = 11.76 C0 = 1.02 x 10íS

.I

n = 1.95 S = 2.5 C0 = 1.01 x 10íS Additionally, per A-4300(b)(2), if the fatigue crack growth rate from light-water reactor environments is lower than air environments, the rate in air should be used.

Alloy 52M Weld Metal in Air Flaw growth in the IDTB Weld (Alloy 52M) and/or Alloy Nozzle in contact with air due to cyclic loading is calculated using the fatigue crack growth model presented in NUREG/CR-6907 (Reference [5]), which specifies a Page 12

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary multiplier of 2 to be applied to the Alloy 600 crack growth rate. Section 1.0 of NUREG/CR-6907 (Reference [5])

details the Alloy 600 crack growth rate equations Crack growth analysis is then conducted on a cycle-by-cycle basis to the end of service life.

The crack growth rate equation for Alloy 52M in air to be used is then given by:

= 2 ()

Where '.LVWKHVWUHVVLQWHQVLW\IDFWRUUDQJHLQWHUPVRI03D¥PDQGGDG1LVWKHFUDFNJURZWKUDWHLQWHUPVRI

m/cycle, and C = 4.835x10-14 + 1.622x10-16T - 1.490x10-18T2 + 4.355x10-21T3 SR = [1 - 0.82R]-2.2 T = degrees C n = 4.1 R = Kmin / Kmax Alloy 52M Weld Metal in Light Water Reactor Environments The fatigue growth rate of Alloy 52M in contact with light-water reactor environment due to cyclic loading is calculated using the fatigue crack growth model presented in NUREG/CR-6907 (Reference [5]), which specifies a multiplier of 2 to be applied to the Alloy 600 crack growth rate. Crack growth analysis is then conducted on a cycle by-cycle basis to the end of service life. Section 1.0 of NUREG/CR-6907 (Reference [5]) details the Alloy 600 crack growth rate equations.

The crack growth rate equation for Alloy 52M in light water environment to be used is then given by:

= 2 ()

Where 'K is the streVVLQWHQVLW\IDFWRUUDQJHLQWHUPVRI03D¥PDQGGDG1LVWKHFUDFNJURZWKUDWHLQWHUPVRI

m/cycle, with:

C = 4.835x10-14 + 1.622x10-16T - 1.490x10-18T2 + 4.355x10-21T3 SR = [1 - 0.82R]-2.2 SENV = 1 + A(C SR 'Kn)m-1 TR1-m A = 4.4 x 10-7 m = 0.33 T = degrees C n = 4.1 R = Kmin / Kmax TR = rise time, set at 30 seconds Page 13

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 2.1.4 PWSCC Crack Growth in Alloy 52M PWSCC crack growth in Alloy 52M is considered for the lower triple point only, as it is subject to primary water environment. PWSCC crack growth in Alloy 52M is assessed using the [ ] factor of improvement [

] over the disposition equation 4.5 of MRP-115 (Reference [7]) that is applicable for Alloy 182. [

] The PWSCC crack growth rate equation for Alloy 52M is given by:

1 1

= 1.5 10 1.6 Where the crack growth rate is in units of m/sec and the stress intensity factor K is in units of MPam. The other constants are given by:

[ ]

Q = thermal activation energy for crack growth = 31,000 cal/mol R = universal gas constant = 1.987 cal/mole-k Tref = absolute reference temperature used to normalize data = 598.15 K (325oC)

T = metal temperature (at crack location) in units of kelvin forient = factor for crack growth orientation = 1.0 falloy = factor for weld alloy type = 1.0 for Alloy 182 2.1.5 General Corrosion in Low Alloy Steel For the postulated flaws in the low alloy steel RVCH material at the lower triple point location exposed to primary water, general corrosion is considered, which is added on a yearly basis to the flaw growth due to fatigue and PWSCC.

2.2 Flaw Acceptance Criteria 2.2.1 Axial and Circumferential Flaw Acceptance Criteria For postulated axial and circumferential flaws in the Alloy 52M repair weld, the acceptance criteria in IWB-3642 (Reference [2]) are used. IWB-3642 states that piping containing flaws exceeding the acceptance standards of IWB-3514.1 may be evaluated using analytical procedures described in Appendix C and is acceptable for continued service during the evaluated time period when the critical flaw parameters satisfy the criteria in Appendix C.

According to C-4230, for flaws in Ni-Cr-Fe weld metal, flaw evaluation procedures of C-4210 shall be used. Based on Figure C-4210-1, for a flaw in austenitic/Ni-Cr-Fe weld material that uses non-flux welds, Section C-5000, is to be used for flaw evaluation.

2.2.2 Cylindrical Flaw Criteria SA-533 Grade B Low Alloy Steel Material (RVCH)

For the postulated cylindrical flaw in the low alloy steel RVCH material, IWB-3613 acceptance criteria of Section XI (Reference [2]) are used. According to IWB-3613, a flaw is acceptable if the applied stress intensity factor for the end of life flaw dimensions af and lf satisfy the following criteria.

IWB-3613(a): For conditions where pressurization does not exceed 20% of the design pressure during which the minimum temperature is not less than RTNDT:

Page 14

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary KI < KIc ¥

IWB-3613(b): For Normal conditions (including Upset and Test conditions) excluding those described in IWB-3613(a):

KI < KIc ¥ (criteria of IWB-3612(a))

IWB-3613(c): For Emergency and Faulted conditions:

KI < KIc ¥ (criteria of IWB-3612(b))

Where:

KI = applied stress intensity factor at the appropriate conditions for flaw dimension af.

KIc = fracture toughness based on crack initiation for the corresponding crack-tip temperature af = end-of-evaluation-period flaw depth Per Section A-4200:

KIc = H[S> 7í57NDT)]

Where, KIc is in units of ksiin and T and RTNDT and in units of oF. Fracture toughness curves for SA-533 Grade B Class 1 material is illustrated in Figure A-4200-1.

Alloy 52M Weld Metal For the postulated cylindrical flaw in the Alloy 52M weld repair material, IWB-3642 acceptance criteria is not evaluated since a limit load solution is not available for such a flaw in the ASME B&PV Code. The shear stress at the remaining ligament for the maximum crack growth for this flaw type at the end of the plant life is evaluated per NB-3227.2.

Page 15

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 3.0 ASSUMPTIONS 3.1 Unverified Assumptions There are no unverified assumptions used herein.

3.2 Justified Assumptions The following justified assumptions are used herein.

3.3 Modeling Simplifications The following modeling simplifications are used herein.

1. Dimensions used for the analyses are based on nominal values. This is considered to be standard practice in stress analysis and fracture mechanics analysis.

Page 16

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 4.0 DESIGN INPUTS 4.1 Geometry Flaw growth calculations are performed along the paths illustrated in Figure 2-1, which originate from either the upper or lower triple point locations. Dimensions used for the flaw evaluations are listed in Table 4-1 for the as-left configuration using the contingency shallow cut repair per Section 2.13 of Reference [1]. Per Section 3.3, Item 1, nominal dimensions are used.

Table 4-1: Path Geometry Page 17

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 4.2 Material The regions of interest for the present flaw evaluations are the upper and lower triple point locations, where three different materials intersect. These materials are the existing or the replacement nozzle material, the new IDTB repair weld material and the RVCH material. As specified in Section 5.0 of Reference [1], the existing nozzle material is SB-166 Alloy 600, the replacement nozzle material is SB-166/167 Alloy 690, the new IDTB weld material is Alloy 52M, and the RVCH is fabricated of SA-533 Grade B Class 1.

4.2.1 Material Strength The material strength pertinent for the flaw evaluation assessment of the weld anomaly in this document. Table 4-2 OLVWVWKHYDOXHVRI\LHOGVWUHQJWK y DQGXOWLPDWHVWUHQJWK ult) obtained from Reference [4].

Table 4-2: Material Strength Ultimate Design Stress Temperature Yield Strength Material Component Strength Intensity

(°F) Sy (ksi)

Sult (ksi) Sm (ksi) 70 50.0 80.0 26.7 400 44.5 80.0 26.7 SA-533 Gr. B Cl. 1 RVCH 500 43.2 80.0 26.7 600 42.0 80.0 26.7 700 41.4 80.0 26.7 70 35.0 85.0 23.3 500 27.8 80.8 23.3 Alloy 52M(1) IDTB Weld 600 27.6 80.2 23.3 700 27.6 79.8 23.3 Note(s):

(1) Equivalent SB-166 Alloy 690 properties 4.2.2 Fracture Toughness For the low alloy steel RVCH material, the maximum nil ductility temperature (RTNDT) is 10 °F (Table 3-2 of Reference [10]). Fracture toughness curves for SA-533 Grade B Class 1 material is illustrated in Figure A-4200-1 of Reference [2]. At the 100% operating temperature [ ] , the KIc fracture toughness for this material (using RTNDT of 10 °F) is DERYHNVL¥LQ$QXSSHUERXQGYDOXHRINVL¥LQis conservatively used for the present flaw evaluations.

Page 18

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 4.3 Loads and Stresses 4.3.1 Transient Stresses The cyclic operating stresses that are used to calculate crack growth are obtained from the Section III stress and fatigue analysis calculation (Reference [4]). These cyclic stresses are developed for transients at a number of time points to capture the maximum and minimum stresses due to fluctuations in pressure and temperature. The number of RCS design transients is established for 60 years of design life (Section 4.2 of Reference [1]). The transient cycle counts used in this calculation are obtained from Reference [11]. The operating transients are listed in Table 4-3.

Consistent with Figure 2-1, all radial paths go from OD to ID of the IDTB weld; all the vertical paths go from top to bottom. Stresses are provided for [ ] equidistant intervals along the path lines.

Table 4-3: Operating Transients and Cycles Page 19

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 4.3.2 Weld Residual Stresses The weld residual stress (WRS) analysis of the RVCH CEDM penetration No. 46 as-left J-groove weld and IDTB repair weld is documented in Reference [3]. This analysis includes weld simulation of the existing J-groove butter, the J-groove weld attaching the CEDM nozzle to the RVCH, and the new IDTB repair weld. The state of stress after welding and sufficient cycles between shutdown and normal operating pressure/temperature to achieve shakedown of stresses, as predicted by the finite element analysis is determined. The linearized stress profiles along selected path lines at the IDTB and RVCH necessary for the fracture mechanics assessment of the triple point anomaly are summarized in Appendix A of Reference [3]. Consistent with Figure 2-1, all radial paths go from OD to ID of the IDTB weld, and all the vertical paths go from top to bottom. Weld residual stresses are provided for [ ] equidistant intervals along the path lines. Since transient stresses from Reference [4] as described in Section 4.3.1 are provided for [ ] equidistant intervals along the path lines, residual stresses are mapped to [ ] equidistant intervals to match stress distribution from Reference [4].

4.3.3 External Loads 4.3.4 Crack Face Pressure Loads For flaw growth in the lower triple point locations, it is conservatively assumed that primary water gets into the flaw and the crack faces are subjected to an additional fluid pressure load. The maximum operating pressure load of [ ] is conservatively used.

4.4 General Corrosion Per Section 2.1.5, for the postulated flaws in the low alloy steel RVCH material at the lower triple point location exposed to primary water, general corrosion is considered, which is added on a yearly basis to the flaw growth due to fatigue and PWSCC. Section 4.1.1.4 of Reference [12] conservatively estimates the general corrosion rate as

[ ] inches per year (radially).

Page 20

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 5.0 COMPUTER USAGE 5.1 Software To validate the installation of AREVACGC 6.0 (Reference [13]), Test Case 1 and 9 provided in Reference [13]

(TestCase1.xls and TestCase9.xls) is executed. The installation of the software on a PC workstation is documented below and verification tests of similar applications are listed as follows.

x Computer programs tested: AREVACGC 6.0 x Name of person running the tests: Jennifer Nelson x Date of tests: Oct 03, 2022 and Oct 13, 2022 x Acceptability: Results agree with those documented for the corresponding test case in Reference [13].

In addition, to Appendix A contains verification of the excel macro KIeff_edge, which is used to calculate the SIF intensity factor for the cylindrical flaw 5.2 Computer Files The computer files used for this evaluation are listed in Table 5-1.

Table 5-1: Computer Files

[/][cold]/[General-Access]/ [ ] /[official]/

Name Size Date/Time Modified CRC Perm Owner AXIAL_FLAW_PATHS_01_02_03.xlsm 1192745 Oct 11 2022 10:11:31 01952 -rw-dc jnelson AXIAL_FLAW_PATHS_07_08_09.xlsm 1209423 Oct 05 2022 09:57:35 02502 -rw-dc jnelson CIRC_FLAW_PATHS_01_02_03.xlsm 1924934 Oct 11 2022 11:23:39 56706 -rw-dc jnelson CIRC_FLAW_PATHS_07_08_09.xlsm 1941468 Oct 05 2022 10:06:15 14841 -rw-dc jnelson CYL_FLAW_PATH_10_BOT.xls 1569792 Oct 12 2022 17:44:11 40011 -rw-dc jnelson CYL_FLAW_PATH_10_TOP.xls 2889216 Oct 13 2022 14:29:35 31405 -rw-dc jnelson CYL_FLAW_PATH_11_BOT.xls 1569792 Oct 12 2022 17:47:02 60691 -rw-dc jnelson CYL_FLAW_PATH_11_TOP.xls 2889728 Oct 13 2022 14:36:46 34548 -rw-dc jnelson CYL_FLAW_PATH_12_BOT.xls 1569792 Oct 12 2022 17:52:49 04552 -rw-dc jnelson CYL_FLAW_PATH_12_TOP.xls 2889728 Oct 13 2022 14:38:44 30506 -rw-dc jnelson CYL_FLAW_PATH_4_BOT.xls 1666560 Oct 05 2022 15:24:28 05720 -rw-dc jnelson CYL_FLAW_PATH_4_TOP.xls 4078592 Oct 05 2022 15:30:06 50804 -rw-dc jnelson CYL_FLAW_PATH_5_BOT.xls 1668096 Oct 05 2022 15:26:11 13656 -rw-dc jnelson CYL_FLAW_PATH_5_TOP.xls 4073984 Oct 12 2022 09:39:17 16747 -rw-dc jnelson CYL_FLAW_PATH_6_BOT.xls 1668096 Oct 05 2022 15:29:45 50293 -rw-dc jnelson CYL_FLAW_PATH_6_TOP.xls 4078080 Oct 05 2022 14:13:07 57039 -rw-dc jnelson K1_Edge_Verification.xls 422400 Oct 03 2022 15:49:16 35231 -rw-dc jnelson TestCase1.xlsm 182233 Oct 03 2022 15:54:11 51861 -rw-dc jnelson TestCase1_After.xlsm 214153 Oct 13 2022 15:08:09 00739 -rw-dc jnelson TestCase9.xlsm 259205 Oct 03 2022 16:35:34 26637 -rw-dc jnelson TestCase9_After.xlsm 259392 Oct 13 2022 15:09:14 32121 -rw-dc jnelson Page 21

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 6.0 CALCULATIONS 6.1 OD Circumferential Flaw in Alloy 52 IDTB Weld 6.1.1 Circumferential Flaw Growth As described in Section 2.1, AREVACGC 6.0 is used to calculate flaw growth for a 360° continuous circumferential flaw postulated at the outside surface of the new Alloy 52 IDTB weld, which propagates in the horizontal direction toward the inside surface of the new IDTB weld along Paths 1, 2, 3 and 7, 8, 9 (see Figure 2-1). Per Section 1.0, flaw growth is assessed from the time of IDTB weld installation in 2021 through 60 years of operation in 2038, for a total of 17 years. Note that in AREVACGC, for a 360 degree circumferential flaw, the origin of the coordinate for path line stresses is at the pipe ID for all flaw locations (ID or OD flaws). Therefore, the WRS, transient stresses and temperatures provided in References [3] and [4] are reversed since the path results (Paths 1, 2, 3 and 7, 8, 9) originate from the OD. As noted in Section 2.1.4, PWSCC crack growth in Alloy 52M is considered for the lower triple point only (Paths 7, 8, 9), as it is subject to primary water environment.

Table 6-1 summarizes the 360° circumferential flaw growth results, which are obtained from AREVACGC files CIRC_FLAW_PATHS_01_02_03.xlsm and CIRC_FLAW_PATHS_07_08_09.xlsm (Table 5-1).

Table 6-1: Circumferential Flaw Growth Summary in Alloy 52 IDTB Weld Page 22

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 6.1.2 Circumferential Flaw Evaluation Per Section 2.2.1, Article C-5000 of Reference [2] contains the appropriate end of life flaw evaluation procedure for the OD circumferential flaw. Table 6-2 details the C-5320 limit load evaluation performed to assess the end of life flaw size, af determined in Section 6.1.1 for the postulated continuous circumferential flaw. It is demonstrated that end of life flaw growth for the postulated 360° circumferential flaw is acceptable since the allowable membrane stress (St) is higher than the applied primary membrane stress (m) by the Margin (factor of Stm) listed in Table 6-2.

Table 6-2: Circumferential Flaw C-5320 Limit Load Evaluation in Alloy 52 IDTB Weld Page 23

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 6.2 OD Axial Flaw in Alloy 52 IDTB Weld 6.2.1 Axial Flaw Growth As described in Section 2.1, AREVACGC 6.0 is used to calculate flaw growth for an axially oriented semi-circular flaw postulated at the outside surface of the new Alloy 52 IDTB weld, which propagates in the horizontal direction toward the inside surface of the new IDTB weld along Paths 1, 2, 3 and 7, 8, 9 (see Figure 2-1). A flaw length to depth aspect ratio of [ ] is considered (Section 3.2, Item 4). For each path, crack growth is calculated using both depth location (radial) and surface location (axial) SIF solutions. Flaw growth is assessed from the time of IDTB weld installation in 2021 through 60 years of operation in 2038, for a total of 17 years (Section 1.0). Note that in AREVACGC, for an axial thumbnail flaw, the origin of the coordinates for the path line stresses is at the crack mouth, i.e., origin at the OD for an OD flaw. As noted in Section 2.1.4, PWSCC crack growth in Alloy 52M is considered for the lower triple point only (Paths 7, 8, 9), as it is subject to primary water environment.

Table 6-3 summarizes the axial flaw growth results for both the radial (depth location) and axial (surface location)

SIF solutions, which are obtained from AREVACGC files AXIAL_FLAW_PATHS_01_02_03.xlsm and AXIAL_FLAW_PATHS_07_08_09.xlsm (Table 5-1).

Page 24

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Table 6-3: Axial Flaw Growth Summary in Alloy 52 IDTB Weld Page 25

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 6.2.2 Axial Flaw Evaluation Per Section 2.2.1, Article C-5000 of Reference [2] contains the appropriate end of life flaw evaluation procedure for the OD axial flaw. Table 6-4 details the C-5410 limit load evaluation performed to assess the end of life flaw size, af determined in Section 6.2.1 for the postulated semi-circular axial flaw. It is demonstrated that end of life flaw growth for the postulated axial flaw is acceptable since the allowable flaw depth (aallow) and length (lallow) is greater than the final flaw depth (af) and length (lf) by the Margin listed in Table 6-4.

Table 6-4: Axial Flaw C-5410 Limit Load Evaluation in Alloy 52 IDTB Weld Page 26

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 6.3 Cylindrical Flaw in Alloy 52 IDTB Weld and LAS RVCH 6.3.1 Cylindrical Flaw Growth Per Section 2.1, for cylindrical flaws, crack growth is calculated using visual basic code, KIeff_edge, which uses a SIF solution for a continuous surface crack in a flat plate from Appendix A of Reference [2]. A continuous surface flaw is postulated to lie along the cylindrical interface between the two materials, which propagates vertically downward or upward from the top or bottom of the flaw tip. This flaw, driven by radial stresses, may propagate along either the new Alloy 52M weld material or the SA-533, Gr. B RVCH material. Flaw growth is assessed from the time of IDTB weld installation in 2021 through 60 years of operation in 2038, for a total of 17 years (Section 1.0). [

]

Crack growth for the final year and final crack depth is summarized in Table 6-5 for the Alloy 52 IDTB Weld upper triple point (TOP), Table 6-6 for the Alloy 52 IDTB Weld lower triple point (BOT), Table 6-7 for the low alloy steel (LAS) RVCH upper triple point (TOP) and Table 6-8 for the LAS RVCH lower triple point (BOT).

Results are obtained from files CYL_FLAW_PATH_*_TOP.xls and CYL_FLAW_PATH_*_BOT.xls, where

is the path number (Table 5-1).

Table 6-5: Cylindrical Flaw Growth Summary for Final Year in Alloy 52 IDTB Weld, TOP Page 27

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Table 6-6: Cylindrical Flaw Growth Summary for Final Year in Alloy 52 IDTB Weld, BOT Page 28

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Table 6-7: Cylindrical Flaw Growth Summary for Final Year in LAS RVCH, TOP Page 29

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Table 6-8: Cylindrical Flaw Growth Summary for Final Year in LAS RVCH, BOT Page 30

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 6.3.2 Cylindrical Flaw Evaluation 6.3.2.1 LAS RVCH Cylindrical Flaw Evaluation Per Section 2.2.2, for the postulated cylindrical flaw in the low alloy steel RVCH material, IWB-3613 acceptance criteria of Section XI (Reference [2]) are used. According to IWB-3613, a flaw is acceptable if the applied stress intensity factor for the flaw dimensions af and lf satisfy the criteria that KI < KIc ¥IRUQormal/upset/test conditions where pressure exceeds 20% of the design pressure and KI < KIc ¥ IRU HPHUJHQF\IDXOWHG FRQGLWLRQV and normal/upset/test conditions where pressurization does not exceed 20% of the design pressure during which the minimum temperature is not less than RTNDT. With the exception of [ ] all Level A/B/Test conditions are HYDOXDWHGDJDLQVWWKHPRUHUHVWULFWLYH.,.,F¥FULWHULDindependent of pressure conditions.

Table 6-9 summarizes the results obtained from files CYL_FLAW_PATH_*_TOP.xls and CYL_FLAW_PATH_*_BOT.xls, where

is the path number (Table 5-1), which demonstrates that the IWB-3613 acceptance criteria of Section XI (Reference [2]) are met.

For qualification of the IWB-3613 criteria, the following analysis limitations apply for the IDTB repair:

x The minimum fluid temperature for performing [ ]

x The maximum [ ] transient pressure when the fluid temperature is less or equal to [

]

x The maximum [ ] transient pressure when the fluid temperature is less or equal to [

]

Page 31

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Table 6-9: LEFM Evaluation for Cylindrical Flaw in LAS RVCH Page 32

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 6.3.2.2 Alloy 52 IDTB Weld Cylindrical Flaw Evaluation Per Section 2.2.2, for the postulated cylindrical flaw in the Alloy 52M weld repair material, IWB-3613 acceptance criteria is not evaluated since a limit load solution is not available for such a flaw in the ASME B&PV Code.

Therefore, the shear stress at the remaining ligament for the maximum crack growth for this flaw type at the end of the plant life is evaluated per NB-3227.2 (Reference [2]). Table 6-10 calculated the maximum shear stress in the remaining ligament , which is less than the allowable shear stress, a for the Alloy 52 IDTB weld material.

Therefore, NB-3227.2 is met.

Table 6-10: Shear Stress Evaluation for Cylindrical Flaw in Alloy 52 IDTB Weld Page 33

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary 7.0

SUMMARY

OF RESULTS The results summarized in Table 7-1 demonstrate that a postulated 0.100 inch weld anomaly in the CEDM IDTB weld is acceptable from the time of IDTB weld installation in 2021 through 60 years of operation in 2038, for a total of 17 years. The minimum fracture toughness margins for flaw propagation are acceptable. The limit load analysis performed considering the ductile weld repair material along the horizontal flaw propagation paths shows that for the postulated circumferential and axial flaws, the minimum margin on allowable stress is acceptable.

Fracture toughness margins have also been demonstrated for the postulated cylindrical flaws. Also, for the cylindrical flaws it is shown that the applied shear stress for the remaining ligament is less than the allowable shear stress per NB-3227.2.

For qualification of the IWB-3613 criteria, the following analysis limitations apply for the IDTB repair:

x The minimum fluid temperature for performing [ ]

x The maximum [ ] transient pressure when the fluid temperature is less or equal to [

]

x The maximum [ ] transient pressure when the fluid temperature is less or equal to [

]

Note that per Reference [14], the low temperature overpressure protection (LTOP) lift setting is limited to 430 psig and therefore, [ ] operations are protected from exceeding this pressure at the

[ ] temperatures identified in the limitations above.

Table 7-1: Summary of Results Flaw Type Evaluation Item Result Reference OD Initial Flaw Size Table 6-1 Circumferential Flaw Growth Final Flaw Size Table 6-1 Flaw in Alloy 52 IDTB Weld End of Life Limit Load Margin, Stm Table 6-2 OD Axial Flaw Initial Flaw Size Table 6-3 Flaw Growth in Alloy 52 IDTB Final Flaw Size Table 6-3 Weld End of Life Limit Load Margin, aallow/af Table 6-4 LAS RVCH Flaw Initial Flaw Size Table 6-5 Growth Final Flaw Size Table 6-6 Cylindrical Flaw Alloy 52 IDTB Weld Initial Flaw Size Table 6-7 in LAS RVCH Flaw Growth Final Flaw Size Table 6-8 and Alloy 52 Fracture Toughness Margin Table 6-9 LAS RVCH Fracture IDTB Weld Toughness Fracture Toughness Margin Table 6-9 Alloy 52 Shear Stress Shear Stress Table 6-10 Page 34

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary

8.0 REFERENCES

1. [ ]

2.

3. [

]

4. [

]

5. NUREG/CR-6907, Crack Growth Rates of Nickel Alloy Welds in a PWR Environment, U.S. Nuclear Regulatory Commission (Argonne National Laboratory), May 2006.

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

7. Materials Reliability Program: Crack Growth Rates for Evaluating Primary Water Stress Corrosion Cracking (PWSCC) of Alloy 82, 182, and 132 Welds (MRP-115), November 2004.

8. Materials Reliability Program: Technical Basis for Reexamination Interval Extension for Alloy 690 PWR Reactor Vessel Top Head Penetration Nozzles (MRP-375), February 2014.

9. [ ]

10. Westinghouse Report WCAP-18169-NP, Rev.1, Arkansas Nuclear One Unit 2 Heatup and Cooldown Limit Curves for Normal Operation, June 2018.

11. [

]

12. [

]

13. [

]

14. Arkansas Nuclear One, Unit 2, Safety Analysis Report Amendment 30 (Redacted), April 2022 (ADAMS Accession No. ML22124A153).

Page 35

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary APPENDIX A: VERIFICATION OF EXCEL MACRO KIEFF_EDGE This Appendix provides verification of the Excel macro KIeff_edge used to calculate the SIF intensity factor for the cylindrical flaw which considers plasticity correction. The test case considered in this Appendix used ao = 0.05 inch, t = 0.5 inch, a/l = 0, and Vy = 41.45 ksi.

Basis: Analysis of Flaws, ASME Code,Section XI, Appendix A, Reference [2].

KI = [ A0 G0 + A1 G1 + A2 G2 + A3 G3 @¥ D4 where 4 DO 1.65 - qy and qy = [ (A0 G0 + A1 G1 + A2 G2 + A3 G3 y ]2 / 6 Page 36

Document No. 32-9357272-000 PROPRIETARY IDTB Weld Anomaly Assessment at CEDM Nozzle No. 46 at ANO Non-Proprietary Page 37

ENCLOSURE 2, ATTACHMENT 2 2CAN012302

[ ]

Document Number 32-9357372-000 (NON-PROPRIETARY)

0402-01-F01 (Rev. 021, 03/12/2018)

CALCULATION

SUMMARY

SHEET (CSS)

Document No. 32 - 9357372 - 000 Safety Related: Yes No ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis -

Title Non-Proprietary PURPOSE AND

SUMMARY

OF RESULTS:

Purpose:

The purpose of the present analysis is to determine, from a fracture mechanics viewpoint, the suitability of leaving a degraded J-Groove weld in the Arkansas Nuclear One (ANO) Unit 2 Reactor Vessel Closure Head (RVCH) following the repair of Control Element Drive Mechanism (CEDM) nozzle penetration #46 for the remaining licensed life of ANO Unit 2. It is postulated that a radial-axial corner flaw exists through the entire J-Groove weld and buttering. This document complements previous flaw evaluation work that supported a one cycle justification of plant operation.

The purpose of Revision 001 is to add proprietary bracketing. The results and conclusions of the analysis are not affected. The proprietary version of this document is 32-9352384-001.

Summary of Results:

A fatigue crack growth and fracture mechanics evaluation for the end-of-evaluation period flaw sizes of the postulated flaws in the as-left J-Groove weld and buttering at ANO-2 CEDM Nozzle penetration #46 has been performed. Additionally, a fracture mechanics evaluation for the limiting intermediate flaw sizes of the postulated flaws is performed in Appendix C. Based on a combination of linear elastic and elastic-plastic fracture mechanics analyses, the postulated flaws are shown to be acceptable for the remaining life of the plant scheduled to end in 2038 for a total of 17 years after an IDTB repair utilizing the safety factors listed in Table 3-1, and the applicable J-R Curve from [ ] as limited by the conditions outlined below.

Analysis Limitations for IDTB Repair*:

The minimum fluid temperature for performing [ ] is

[ ]

The maximum [ ] transient pressure when the fluid temperature is less or equal to [ ] is

[ ]

The maximum [ ] transient pressure when the fluid temperature is less or equal to [ ] is

[ ]

(*) Note that, per Section 5.2.2.4 of Reference [27], the low temperature overpressure protection (LTOP) lift setting is limited to 430 psig for RC fluid temperature less or equal to 220°F and therefore, [ ] operations are protected from exceeding this pressure at the [ ] temperatures identified in the analysis limitations above.

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, THE DOCUMENT CONTAINS AP 0402-01 requires that justification be provided.

ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE CODE/VERSION/REV CODE/VERSION/REV Yes ANSYS 19.2 (See Section 6.1)

No Page 1 of 94

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 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 P/R/A/M Name and Title and Pages/Sections (printed or typed) Signature LP/LR Date Prepared/Reviewed/Approved Luziana Matte, LR MATTE Advisory Engineer LP All 12/7/2022 Martin Kolar, Principal Engineer M KOLAR LR All 12/7/2022 Ryan Hosler, RS HOSLER Supervisory Engineer 12/7/2022 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 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 Title (printed or typed) (printed or typed) Signature Date Comments N/A N/A N/A N/A N/A Page 2

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Record of Revision Revision Pages/Sections/Paragraphs No. Changed Brief Description / Change Authorization Original Release. The proprietary version of this 000 All document is 32-9352384-001.

Page 3

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table of Contents Page SIGNATURE BLOCK ................................................................................................................................ 2 RECORD OF REVISION .......................................................................................................................... 3 LIST OF TABLES ..................................................................................................................................... 6 LIST OF FIGURES ................................................................................................................................... 8

1.0 INTRODUCTION

........................................................................................................................... 9 2.0 PURPOSE ..................................................................................................................................... 9 3.0 ANALYTICAL METHODOLOGY ................................................................................................. 10 3.1 Stress Intensity Factor Solution ...................................................................................................... 11 3.1.1 Plastic Zone Correction .................................................................................................... 11 3.2 Fatigue Crack Growth ..................................................................................................................... 16 3.3 Stress Corrosion Crack Growth ...................................................................................................... 17 3.4 Acceptance Criteria ......................................................................................................................... 17 3.4.1 Linear Elastic Fracture Mechanics.................................................................................... 17 3.4.2 Elastic-Plastic Fracture Mechanics ................................................................................... 18 3.4.3 Primary Stress Analysis .................................................................................................... 20 3.4.4 Summary of Safety Factors for Flaw Acceptance ............................................................ 20 4.0 ASSUMPTIONS .......................................................................................................................... 22 4.1 Unverified Assumptions................................................................................................................... 22 4.2 Justified Assumptions...................................................................................................................... 22 4.3 Modeling Simplifications .................................................................................................................. 23 5.0 DESIGN INPUTS ........................................................................................................................ 24 5.1 Geometry ......................................................................................................................................... 24 5.2 Materials .......................................................................................................................................... 24 5.2.1 Material Specifications ...................................................................................................... 24 5.2.2 Mechanical Material Properties ........................................................................................ 25 5.2.3 Fracture Material Properties ............................................................................................. 26 5.3 Transients ........................................................................................................................................ 29 5.4 Finite Element Model....................................................................................................................... 30 5.4.1 Boundary Conditions ........................................................................................................ 30 5.4.2 Applied Stresses ............................................................................................................... 30 6.0 COMPUTER USAGE .................................................................................................................. 32 6.1 Software and Hardware................................................................................................................... 32 6.2 Computer Files ................................................................................................................................ 32 Page 4

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table of Contents (continued)

Page 7.0 CALCULATIONS ......................................................................................................................... 37 7.1 Stress Intensity Factors ................................................................................................................... 37 7.2 Crack Tip Metal Temperatures ........................................................................................................ 37 7.3 Crack Growth .................................................................................................................................. 37 7.4 LEFM Evaluation ............................................................................................................................. 39 7.5 EPFM Evaluations ........................................................................................................................... 43 7.6 Primary Stress Evaluation ............................................................................................................... 46 7.6.1 Limit Load Finite Element Analysis ................................................................................... 46 7.6.2 Calculation of Flaw Area Removed .................................................................................. 51

8.0 CONCLUSION

S .......................................................................................................................... 54 8.1 Analysis Limitations for IDTB Repair............................................................................................... 54

9.0 REFERENCES

............................................................................................................................ 55 APPENDIX A : UPHILL SIDE FLAW EVALUATIONS........................................................................... 57 APPENDIX B : DOWNHILL SIDE FLAW EVALUATIONS .................................................................... 77 APPENDIX C : LEFM AND EPFM FLAW EVALUATION AT LIMITING INTERMEDIATE FLAW SIZES ........................................................................................................................... 88 Page 5

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary List of Tables Page Table 3-1: Safety Factors for Flaw Acceptance ..................................................................................... 21 Table 5-1: Key Dimensions .................................................................................................................... 24 Table 5-2: Component Materials............................................................................................................ 25 Table 5-3: RVCH Material Properties .................................................................................................... 25 Table 5-4: J-Groove Weld, and Butter Material Properties .................................................................... 26 Table 5-5: Cladding Material Properties ................................................................................................ 26 Table 5-6: CVN Test Data...................................................................................................................... 27 Table 5-7: Operating Transients and Cycles ......................................................................................... 29 Table 5-8: Stress Result Files ................................................................................................................ 30 Table 6-1: Computer Files ..................................................................................................................... 32 Table 7-1: Flaw Growth Summary and Maximum SIF ........................................................................... 38 Table 7-2: LEFM Results - Uphill [ ] ..................................................................................... 41 Table 7-3: LEFM Results - Downhill [ ]............................................................................... 42 Table 7-4: EPFM Results - Uphill [ ] ..................................................................................... 44 Table 7-5: EPFM Results - Downhill [ ] .............................................................................. 45 Table 7-6: Model Areas Removed by the Cutouts to Represent Postulated Flaws ............................... 52 Table 7-7: Flaw Area Comparison ......................................................................................................... 53 Table A-1: Fatigue Crack Growth for Transient [ ] (Uphill) ................. 58 Table A-2: Fatigue Crack Growth for Transient [ ] (Uphill) .................. 59 Table A-3: Fatigue Crack Growth for Transient [ ] (Uphill) ................... 60 Table A-4: Fatigue Crack Growth for Transient [ ] (Uphill) .................... 61 Table A-5: Fatigue Crack Growth for Transient [ ] (Uphill) .............. 62 Table A-6: Fatigue Crack Growth for Transient [ ] (Uphill) ....................... 63 Table A-7: Fatigue Crack Growth for Transient [ ] (Uphill) ...................... 64 Table A-8: Stress Corrosion Crack Growth - [ ] (Uphill) .................................. 65 Table A-9: Fatigue Crack Growth for Transient [ ] (Uphill) ............... 66 Table A-10: Fatigue Crack Growth for Transient [ ] (Uphill) .............. 67 Table A-11: Fatigue Crack Growth for Transient [ ] (Uphill) ............... 68 Table A-12: Fatigue Crack Growth for Transient [ ] (Uphill) ................ 69 Table A-13: Fatigue Crack Growth for Transient [ ] (Uphill) .......... 70 Table A-14: Fatigue Crack Growth for Transient [ ] (Uphill) ................... 71 Page 6

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary List of Tables (continued)

Page Table A-15: Fatigue Crack Growth for Transient [ ] (Uphill) .................. 72 Table A-16: Stress Corrosion Crack Growth - [ ] (Uphill) .............................. 73 Table A-17: EPFM Evaluation [ ] (Uphill) ......................................... 74 Table B-1: Fatigue Crack Growth for Transient [ ] (Downhill) .......... 78 Table B-2: Fatigue Crack Growth for Transient [ ] (Downhill) ........... 79 Table B-3: Fatigue Crack Growth for Transient [ ] (Downhill) ............ 80 Table B-4: Fatigue Crack Growth for Transient [ ] (Downhill).............. 81 Table B-5: Fatigue Crack Growth for Transient [ ] (Downhill) ....... 82 Table B-6: Fatigue Crack Growth for Transient [ ] (Downhill) ................ 83 Table B-7: Fatigue Crack Growth for Transient [ ] (Downhill) ............... 84 Table B-8: Stress Corrosion Crack Growth - [ ] (Downhill) ............................ 85 Table B-9: EPFM Evaluation [ ] (Downhill)................................... 86 Table C-1: LEFM Results - Uphill [ ] ................................................................. 90 Table C-2: LEFM Results - Downhill [ ]........................................................... 91 Table C-3: EPFM Results - Uphill [ ] ................................................................. 93 Table C-4: EPFM Results - Downhill [ ] .......................................................... 93 Table C-5: EPFM Evaluation [ ] (Uphill) [ ] ................... 94 Table C-6: EPFM Evaluation [ ] (Downhill) [ ] .......... 94 Page 7

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary List of Figures Page Figure 3-1: Finite Element Model Isometric View .................................................................................. 12 Figure 3-2: Uphill Crack Fronts .............................................................................................................. 13 Figure 3-3: Downhill Crack Fronts ......................................................................................................... 14 Figure 3-4: Initial Flaw Sizes .................................................................................................................. 15 Figure 5-1: J-R Curves as a Function of Temperature .......................................................................... 28 Figure 5-2: [ ] .............................. 31 Figure 7-1: Limit Load Model Penetration Layout .................................................................................. 47 Figure 7-2: Limit Load Model Geometry ................................................................................................ 48 Figure 7-3: Limit Load Model Finite Element Mesh ............................................................................... 49 Figure 7-4: Equivalent Stresses at the Final Load Step (psi)................................................................. 50 Figure 7-5: Area Calculation Diagram.................................................................................................... 51 Figure 7-6: Penetration No. 46 Initial Crack Face Areas ....................................................................... 53 Figure A-1: J-T Diagram [ ] (Uphill) .................................................. 75 Figure A-2: J-a Diagram [ ] (Uphill) ................................................ 76 Figure B-1: J-T Diagram [ ] (Downhill) ......................................... 87 Page 8

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary

1.0 INTRODUCTION

During the Fall 2021 outage (2R28), as a part of the ultrasonic examination (UT) for the in-service inspection at Arkansas Nuclear One Unit 2 (ANO-2), an axial indication was discovered on the downhill side of the Control Element Drive Mechanism (CEDM) Penetration #46 on the reactor vessel closure head (RVCH). Subsequently, a RVCH CEDM nozzle penetration modification was performed at this penetration.

The modification consists of the removal and replacement of the lower portion of the existing CEDM nozzle (including nozzle guide) at CEDM Penetration #46. The upper portion of the nozzle shall remain in place. The modification removes a portion of the pressure boundary partial penetration J-groove weld existing on the inside of the RVCH. The new pressure boundary weld is in the RVCH penetration bore above the original weld. The new nozzle to RVCH pressure boundary weld was then deposited using the machine Gas Tungsten Arc Welding (GTAW) process.

The purpose of Revision 001 is to add proprietary bracketing. The results and conclusions of the analysis are not affected.

2.0 PURPOSE The purpose of this calculation is to determine from a fracture mechanics viewpoint the suitability of leaving a degraded J-groove weld in the ANO-2 RVCH following the repair of CEDM nozzle penetration

46. Since a potential flaw in the J-groove weld and buttering cannot be sized by currently available non-destructive examination techniques, it is conservatively assumed that the as-left condition of the remaining J-groove weld includes degraded or cracked weld material extending through the entire J-groove weld and butter materials.

It is conservatively postulated that a radial-axial flaw exists through the entire J-groove weld and buttering and would propagate into the low alloy steel RVCH material by fatigue crack growth under cyclic loading conditions. [

]

Per Reference [1], the applicable code is ASME Section XI, 2007 Edition with Addenda through 2008 (Reference [2]). If the service life of the component is shown to be limited, an alternate approach of using ASME Section XI Code Case N-749 (Reference [3]) as modified by the Regulatory Guide 1.147, Revision 19 (Reference [4]) will be considered in the evaluation. Acceptance of each postulated flaw is determined based on available fracture toughness or ductile tearing resistance using the safety factors outlined in Table 3-1.

Predictions of fatigue crack growth are applicable through the remaining service life of the plant scheduled to end in 2038 for a total of 17 years after the installation of the modification in 2021.

Page 9

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 3.0 ANALYTICAL METHODOLOGY The basic analytical methodology is outlined below. Details are provided in the following subsections.

1. Postulate radial-axial flaws in the J-Groove weld and butter of the RVCH penetration #46 location.

[ ]

2. [

]

3. [

]

4. [

]

5. Calculate fatigue crack growth [ ] for cyclic loading conditions using operational stresses from pressure and thermal loads and crack growth rates from Article A-4300 of Section XI, Reference [2], for ferritic material in a primary water environment. [

]

6. Utilize the screening criteria of ASME Code Case N-749 (Reference [3]) as modified by Regulatory Guide 1.147, Revision 19 (Reference [4]) to determine the appropriate method of analysis (LEFM or EPFM). For LEFM flaw evaluations, compare the stress intensity factors to the available fracture toughness, with appropriate safety factors. When the material is more ductile and EPFM is the appropriate analysis method, evaluate in accordance with ASME Code Case N-749 (Reference [3]).

7. A limit load analysis is performed to demonstrate that Items 3.1(c) or 3.2(a)(3) of Reference [3]

are satisfied. Items 3.1(c) or 3.2(a)(3) requires that the primary stress limit of NB-3000 are satisfied, considering a local reduction of the pressure boundary area equal to the area of the flawed material.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 3.1 Stress Intensity Factor Solution The SIF solutions for the postulated flaws evaluated by fracture mechanics analysis are calculated using

[

]

Radial-axial flaws are postulated and analyzed separately on the uphill and downhill sides of the nozzle penetration as shown in Figure 3-2 and Figure 3-3. [

]

3.1.1 Plastic Zone Correction The Irwin plastic zone correction is used to account for a moderate amount of yielding. [

]

Page 11

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure 3-1: Finite Element Model Isometric View Page 12

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure 3-2: Uphill Crack Fronts Page 13

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure 3-3: Downhill Crack Fronts Page 14

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure 3-4: Initial Flaw Sizes Page 15

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 3.2 Fatigue Crack Growth Fatigue crack growth is calculated using the fatigue crack growth rate model from Article A-4300 of Reference [2] as follows:

= 0 ( )

Where is the stress intensity factor range in ksiin, and da/dN is the crack growth rate in inches/cycle.

The crack growth rates for a surface flaw will be utilized since the postulated flaw(s) would result in the low alloy steel head being exposed to the primary water environment.

The detailed equations for calculating the fatigue crack growth rate are presented below.

=

= /

0 0.25, < 17.74

= 5.95

= 1.0 0 = 1.02 x 1012 17.74

= 1.95

= 1.0 0 = 1.01 x 107 0.25 < < 0.65, < 17.74[(3.75 + 0.06)(26.9 5.725)]0.25

= 5.95

= 26.9 5.725 0 = 1.02 x 1012 17.74[(3.75 + 0.06)(26.9 5.725)]0.25

= 1.95

= 3.75 + 0.06 0 = 1.01 x 107 0.65 1.00, < 12.04

= 5.95

= 11.76 0 = 1.02 x 1012 12.04

= 1.95

= 2.5 0 = 1.01 x 107 Page 16

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Additionally, per A-4300(b)(2) of Reference [2], if the fatigue crack growth rate from light-water reactor environments is lower than air environments, the rate in air should be used. The fatigue crack growth constants for flaws in an air environment are:

= 3.07 0 = 1.99 x 1010 is a scaling parameter to account for the ratio and is given by = 25.72 (2.88 - ) 3.07 where 0 1 and = .

For < 0, depends on the crack depth, , and the flow stress, . The flow stress is defined as

= 1/2( + ), where is the yield strength and is the ultimate tensile strength.

For 2 0 and 1.12 a,

=1 and = .

For < 2 and 1.12 a,

=1 and = (1 R) /3.

For < 0 and >1.12 a,

=1 and = .

3.3 Stress Corrosion Crack Growth Reference [7] conducted a stress corrosion cracking (SCC) susceptibility assessment that is specifically applicable to the ANO-2 RVCH CEDM nozzle 46. Per Reference [7], [

]

3.4 Acceptance Criteria 3.4.1 Linear Elastic Fracture Mechanics After fatigue crack growth is calculated, the postulated flaws are evaluated using Linear Elastic Fracture Mechanics (LEFM). Article IWB-3613 of Section XI (Reference [2]) requires that the applied stress intensity factor be less than the available fracture toughness at the crack tip temperature, with appropriate safety factor, as outlined below.

IWB-3613(a): For conditions where pressurization does not exceed 20% of the design pressure during which the minimum temperature is not less than :

< /2 IWB-3613(b): For Normal, Upset and Test conditions excluding those described in IWB-3613(a):

< /10 (criteria of IWB-3612(a))

IWB-3613(c): For Emergency and Faulted conditions:

< /2 (criteria of IWB-3612(b))

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary In the above, is the fracture toughness based on crack initiation for the corresponding crack-tip temperature. In the evaluation of the above limits, a plastic zone correction is incorporated using the methodology described in Section 3.1.1.

3.4.2 Elastic-Plastic Fracture Mechanics Elastic-plastic fracture mechanics (EPFM) will be used as an alternative acceptance criteria when the flaw related failure mechanism is unstable ductile tearing. LEFM would be used to assess the potential for non-ductile failure, while limit analysis would be used to check for plastic collapse.

3.4.2.1 Screening Criteria ASME Code Case N-749, Reference [3] states that EPFM acceptance criteria are applicable to ferritic steel components on the upper shelf of the Charpy energy curve when the metal temperature exceeds the upper shelf transition temperature, . Per Regulatory Guide 1.147 Revision 19 (Reference [4]),

is defined as follows:

= 154.8 + 0.82 x (U.S. Customary Units)

Where is the adjusted reference nilductility temperature as described in Section 5.2.3. When the metal temperature exceeds , EPFM analysis is applicable. Additionally, NRC defines in RG 1.147 Revision 19 (Reference [4]), a temperature 1 below which the LEFM method must be applied:

1 = 95.36 + 0.703 x (U.S. Customary Units)

Per Reference [4], between 1 and , while the fracture mode is in transition from LEFM to EPFM, users should consider whether or not it is appropriate to apply the EPFM method.

3.4.2.2 Flaw Stability and Crack Driving Force Elastic-plastic fracture mechanics analysis will be performed based on ASME Code Case N-749 (Reference [3]) to evaluate crack driving force and flaw stability (if applicable). Two possible sets of acceptance criteria for EPFM are defined in Code Case N-749:

Section 3.1 Acceptance Criteria Based Solely on Limited Ductile Crack Extension, or

Section 3.2 Acceptance Criteria Based on Limited Ductile Crack Extension and Stability.

Section 3.1 of Reference [3] states that the flaw is acceptable if the crack driving force, as measured by the applied -integral ( ) with appropriate safety factors applied to the loads, is less than the -integral of the material ( ) at a ductile crack extension of 0.1 inch (0.1 ). If the criteria of Section 3.1 of Reference [3] are not met, the flaw may still be acceptable if the criteria of Section 3.2 of Reference [3]

are met. Section 3.2 allows lower safety factors for the crack driving force check, and additionally requires that flaw stability be evaluated with appropriate safety factors.

The flaw stability analysis will be performed using a -integral/tearing modulus (-) diagram to evaluate flaw stability under ductile tearing, where is either the applied ( ) or the material ( ) -integral, and is the tearing modulus, defined as (/ 2) (/). Flaw stability and crack driving force assessments will utilize the safety factors from Code Case N-749 as outlined in Table 3-1.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary The general methodology for performing an EPFM analyses is outlined below.

The applied -integral is checked against 0.1 , demonstrating that the crack driving force falls below the

- curve at a crack extension of 0.1 inch, per Section 3.1 of Reference [3].

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Flaw stability is demonstrated at an applied -integral when the applied tearing modulus is less than the material tearing modulus. Alternately, the applied -integral is less than the -integral at the point of instability.

[

] Additionally the flaw stability is also demonstrated by plotting the applied -integral at the initial (0 ) and final ( ) crack depths against the crack depth extensions () together with the material ( ) -integral curve and showing that the requirement 4.3(b) of Reference [3], ( / ) < ( / ) is achieved.

3.4.3 Primary Stress Analysis Items 3.1(c) and 3.2(a)(3) of Reference [3] state that the flawed component must meet the primary stress limits of NB-3000, Reference [8], 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 [8] 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 these calculations is 1.5 . Per NB-3112.1(a) the Design Pressure shall be used in showing compliance with this limit.

3.4.4 Summary of Safety Factors for Flaw Acceptance Acceptance of each postulated flaw is determined based on available fracture toughness or ductile tearing resistance using the safety factors outlined in Table 3-1.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table 3-1: Safety Factors for Flaw Acceptance LEFM(1)

Operating Condition Evaluation Method Fracture Toughness /

Normal/Upset fracture toughness 10 = 3.16 or 2 = 1.41(1a, 1b)

Emergency/Faulted fracture toughness 2 = 1.41(1c)

EPFM Based on Limited Ductile Flaw Extension(2)

Operating Condition Evaluation Method Primary Secondary Normal/Upset 0.1 limited flaw extension 2.0 1.0 Emergency/Faulted 0.1 limited flaw extension 1.5 1.0 EPFM Based on Limited Ductile Flaw Extension and Stability (3)

Operating Condition Evaluation Method Primary Secondary Normal/Upset / based flaw stability 2.14 1.0 Normal/Upset 0.1 limited flaw extension 1.5 1.0 Emergency/Faulted / based flaw stability 1.2 1.0 Emergency/Faulted 0.1 limited flaw extension 1.25 1.0 Primary Stress Limits(4)

Operating Condition Evaluation Method Primary Secondary Design Limit Load 1.5 N/A Notes(s):

(1) LEFM safety factors are from IWB-3613 of ASME Section XI (Reference [2]).

a. Per IWB-3613(a), for conditions where pressurization does not exceed 20% of the design pressure during which the minimum temperature is not less than RTNDT:

< /2

b. Per IWB-3613(b), for Normal, Upset, and Test conditions excluding those described in IWB-3613(a):

< /10 (criteria of IWB-3612(a))

c. Per IWB-3613(c), for Emergency and Faulted conditions:

< /2 (criteria of IWB-3612(b))

(2) EPFM safety factors based on Section 3.1 of Code Case N-749 (Reference [3]).

(3) EPFM safety factors based on Section 3.2 of Code Case N-749 (Reference [3]).

(4) Primary stress limits based on NB-3228.1 of ASME Section III (Reference [8]).

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 4.0 ASSUMPTIONS 4.1 Unverified Assumptions No unverified assumptions are used in this calculation.

4.2 Justified Assumptions The following justified assumptions are used in this calculation:

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 4.3 Modeling Simplifications The following modeling simplifications are used in this calculation:

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 5.0 DESIGN INPUTS 5.1 Geometry The existing geometry of the RVCH and J-Groove weld of the RVCH CEDM Penetration No. 46 is shown in Reference [10]. The proposed repair configuration is provided in Reference [11]. Key dimensions are listed in Table 5-1. J-groove weld geometry simplifications are listed in Section 4.3, Items 1 and 2.

Table 5-1: Key Dimensions Description Value RVCH Inside Radius (to base metal) [ ]

RVCH Base Metal Thickness [ ]

Cladding Thickness [ ]

Original CEDM Penetration Bore(1) [ ]

Radial Distance from Nozzle Center to RVCH Center [ ]

Note (1): [ ]

5.2 Materials 5.2.1 Material Specifications The material designations of each component are listed in Table 5-2 per Reference [1].

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table 5-2: Component Materials Component Material RVCH [ ]

Cladding [ ]

J-Groove Weld/Buttering [ ]

Note(s):

[

]

5.2.2 Mechanical Material Properties The mechanical properties for the RVCH, cladding, existing weld and buttering materials are taken from Reference [12]. [

] The material properties for each component are provided in Table 5-3, Table 5-4, and Table 5-5.

Table 5-3: RVCH Material Properties Page 25

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table 5-4: J-Groove Weld, and Butter Material Properties Table 5-5: Cladding Material Properties 5.2.3 Fracture Material Properties Per Reference [14], the applicable RVCH RTNDT is [ ] Per Reference [21], CEDM nozzle No. 46 is located [ ]

Reference [15] provides a sulfur content of [

] and the Charpy V-notch (CVN) test data from the applicable CMTR as listed in Table 5-6.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table 5-6: CVN Test Data Per Reference [16], the Charpy V-notch upper-shelf energy (USE) is defined by ASTM E185 (Reference [17]), which provides the following definition of the USE:

Charpy upper-shelf energy level: the average energy value for all Charpy specimen tests (preferably three or more) whose test temperature is at or above the Charpy upper-shelf onset; specimens tested at temperatures greater than 150°F above the Charpy upper-shelf onset shall not be included, unless no data are available between the onset temperature and onset +150°F.

Charpy upper-shelf onset: the test temperature above which the fracture appearance of all Charpy specimens tested is at or above 95% shear.

From Table 5-6 the lower bound USE of [ ] is selected based on the test data at [

]

From Article A-4200 of Reference [2], the fracture toughness for crack initiation, , is calculated as

= 33.2 + 20.734 x [0.02( )]

Where is the crack tip temperature, is in units of ksiin, and and are in units of °F. In the present calculations, is limited to a maximum value of [ ] (upper-shelf fracture toughness).

The crack initiation upper shelf toughness of [ ] is achieved at [ ]

The -integral resistance (-) curve, needed for the EPFM method of analysis, is obtained from [

]

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure 5-1: J-R Curves as a Function of Temperature The material tearing modulus is calculated using the following equation Page 28

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 5.3 Transients Fatigue crack growth will be calculated for the transients listed in Table 5-7. The cyclic operating hoop stresses are obtained from a thermo-elastic finite element analysis (Reference [18]). Cyclic operating stresses and metal temperatures were generated in Reference [18] for the transients listed in Reference [19].

Per Reference [19], the number of cycles of the RCS design transients is established for the design lifetime of 60 years. Per Reference [1], predictions of fatigue crack growth are applicable through the remaining service life of ANO-2 scheduled to end in 2038 for a total of 17 years after the installation of the modification in 2021.

Table 5-7: Operating Transients and Cycles File Name Number of Condition ID# Transient Convention Cycles Normal Upset Emergency Test Note(s):

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 5.4 Finite Element Model The finite element model utilized is [

]

5.4.1 Boundary Conditions

[

]

5.4.2 Applied Stresses Applied stresses are due to residual stresses and operating stresses. Residual stresses are obtained from the 3-D weld residual stress calculation documented in Reference [9]. [

]

[

] Operating stresses are taken from the corresponding ASME Section III calculation (Reference [18]) [

] The operating pressure is also applied to the crack face to account for the additional loading.

The files used for stress results from References [9] and [18] are listed in Table 5-8. Files generated in Reference [18] also contain operating transients metal temperatures.

Table 5-8: Stress Result Files Load Stress File Reference Note (1): Transient input files from Reference [18] also contain operating transients metal temperatures.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 6.0 COMPUTER USAGE 6.1 Software and Hardware Computer runs for the analysis documented herein are performed using ANSYS Mechanical Enterprise, Release 19.2, Linux (Reference [5]) to solve the following physical problems in this calculation: [

]

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 [28]. Reference [28] demonstrates that ANSYS meet the requirements to be used on the HPC as a controlled access code.

Access node name / hardware: AUSLYNCHPCI04; Intel Xeon CPU E5-2660 v3 @ 2.60GHz

Operating System: Red Hat Enterprise Server v6.4 (Linux); Kernel: 2.6.32-696.28.1.el6.x86_64 This computer is a multi-node HPC, the computing node used to run this analysis was determined by queuing software.

6.2 Computer Files The computer files for runs performed in revision 000 are listed in Table 6-1. Files are stored in ColdStor at the following directory:

\cold\General-Access\32\32-9000000\32-9352384-000\official Table 6-1: Computer Files File Name Size (Bytes) Date/Time Modified CRC Checksum Page 32

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 7.0 CALCULATIONS 7.1 Stress Intensity Factors SIFs are calculated [

] The SIF calculation results are written to the *.KI output files (see Table 6-1), which contain the SIFs for each load step of a transient as well as a summary of the minimum and maximum SIF for the transient.

7.2 Crack Tip Metal Temperatures 7.3 Crack Growth Utilizing the SIF solutions described in Section 7.1, fatigue crack growth is calculated. The fatigue crack growth rule in Section 3.2 is integrated numerically using, 0 ( ) , 0 ( )

Based on review of the results, a summary of the fatigue and SCC crack growths and final flaw sizes for each crack front position and the maximum SIFs calculated at the final flaw sizes are summarized in Table 7-1 for the postulated flaws in the uphill and downhill sides.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table 7-1: Flaw Growth Summary and Maximum SIF Uphill Downhill Page 38

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Per Table 7-1, on the uphill side, position [ ] yields the maximum stress intensity factor at the final flaw size of [ ] Additionally, position [ ] yields the maximum crack growth of [

] after 17 years of plant operation. Position [ ] is the bounding location for the postulated flaw in the uphill side and chosen for detailed evaluation. Fatigue and SCC crack growth calculations for positions [ ] and [ ] on the uphill side are performed in [

] , and the detailed results are shown in Appendix A, Sections A.1 and A.2.

Per Table 7-1, on the downhill side, position [ ] yields the maximum stress intensity factor at the maximum final flaw size of [ ] This location is the bounding location for the postulated flaw on the downhill side and chosen for detailed evaluation. Fatigue and SCC crack growth calculations for position [ ] on the downhill side are performed in [

] and the detailed results are shown in Appendix B, Section B.1.

7.4 LEFM Evaluation LEFM evaluations are performed for the final flaw sizes from the crack growth evaluations. The applied SIF is evaluated accounting for the plastic zone correction described in Section 3.1.1, and its acceptability is evaluated based on the rules outlined in Section 3.4.1. The results for the limiting uphill position [ ]

are shown in Table 7-2. The results for the limiting downhill position [ ] are shown in Table 7-3.

The upper shelf transition temperature, defined in Section 3.4.2.1, above which the EPFM must be applied is calculated as follows:

= 154.8 + 0.82 x = [ ]

The additional temperature limit defined in RG 1.147 rev. 19 (Reference [4]), 1 below which the LEFM method must be applied is calculated as follows 1 = 95.36 + 0.703 x = [ ]

Per Reference [4], between temperatures 1 and , while the fracture mode is in transition from LEFM to EPFM, users should consider whether or not it is appropriate to apply the EPFM method.

[

]

Review of the results of Table 7-2 and Table 7-3 indicates that, with few exceptions, the LEFM acceptance criteria are not met; however, in all cases shown, with the exception of the [

] the temperature exceeds of [ ] and may therefore be analyzed based on EPFM.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary For the [ ] cases, the LEFM results are not acceptable, and the temperature of [ ] does not meet the criteria for analysis by EPFM. Since the [

] cases are [ ] a temperature of

[ ] will be considered and EPFM analysis will be performed. The [ ]

cases will be considered acceptable to meet the EPFM requirements provided that [

] are performed with a fluid temperature of [ ] or greater.

For the [ ] cases evaluated on the uphill and downhill sides [

] , the LEFM results are not acceptable for load step [

] Per Reference [18], these load steps correspond to [

] These [ ]

load steps will be considered acceptable to meeting the LEFM requirements provided that the maximum transient pressure when the fluid temperature is equal to or less than [ ] during [ ] and equal to or less than [ ] during [ ] , is [ ]

Lastly, review of the results also indicates that the LEFM acceptance criteria are met for all cases where the transient fluid temperature or the crack tip metal temperature fall in between the temperatures of 1 and in which the fracture mode is in transition from LEFM to EPFM.

Additional LEFM flaw evaluations for the limiting intermediate flaw sizes are documented in Appendix C.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table 7-3: LEFM Results - Downhill [ ]

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 7.5 EPFM Evaluations For the postulated cracks on the uphill and downhill sides, the EPFM evaluations will be performed at the limiting crack front positions at their final flaw sizes in accordance with the methodology described in Section 3.4.2 [

]

As discussed in the Section 7.4, the limiting load steps of all transients in which the fluid temperature

[ ] may be evaluated using EPFM. Table 7-4 provides the results of the EPFM evaluations for the final flaw size of crack front position [ ] on the uphill side. Table 7-5 provides the results of the EPFM evaluations for the final flaw size of crack front position [ ] on the downhill side. [

]

For the postulated cracks on both the uphill and the downhill sides, as shown in Table 7-4 and Table 7-5, all cases meet the EPFM acceptance criteria. [

] Details of the calculations for the limiting [ ] transient are provided for crack front position [ ] on the uphill side in Appendix A, Section A.3. Details of the calculations for the limiting [ ] transient are provided for crack front position [ ] on the downhill side in Appendix B, Section B.2.

[

]

Additionally, for the postulated crack on the uphill side [

] the flaw stability is also demonstrated by plotting the applied -integral at the initial (0 ) and final ( ) crack depths against the crack depth extensions () together with the material

( ) -integral curve and showing that the requirement 4.3(b) of Reference [3], ( /) < ( / )

is achieved. Plot for the uphill limiting [ ] transient is provided in Figure A-2.

Additional EPFM flaw evaluations for the limiting intermediate flaw sizes are documented in Appendix C.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table 7-4: EPFM Results - Uphill [ ]

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 7.6 Primary Stress Evaluation 7.6.1 Limit Load Finite Element Analysis The acceptance criterion of items 3.1(c) and 3.2(a)(3) of Reference [3] require that the primary stress limits of NB-3000 (Reference [8]) are met assuming a local area reduction of the pressure retaining membrane that is equal to the area of the flaw. As described in Section 3.4.3, the primary stress limits for design conditions (NB-3221.1, NB-3221.2, and NB-3221.3) need not be satisfied if it can be shown by performing a limit analysis (NB-3228.1) that the applied loadings do not exceed two-thirds of the lower bound collapse load. This condition is equivalent to showing that the structure does not collapse at a pressure equal to 150% of the Design Pressure ( [ ] ). In terms of finite element results, plastic collapse of the structure is equivalent to numerical instability.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure 7-2: Limit Load Model Geometry The overall model geometry and mesh are defined in [

] The finite element mesh utilized is shown in Figure 7-3.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure 7-3: Limit Load Model Finite Element Mesh The material properties for the analysis are defined in [

]

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure 7-4: Equivalent Stresses at the Final Load Step (psi)

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary 7.6.2 Calculation of Flaw Area Removed The cross-sectional areas of the material removed to represent the postulated J-Groove flaws plus crack growth (see Figure 3-2 and Figure 3-3) on the uphill side and downhill side are calculated using the following equation (see for Figure 7-5 diagram):

Figure 7-5: Area Calculation Diagram

[

] The resulting areas removed from the ANSYS model are shown in Table 7-6.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure 7-6: Penetration No. 46 Initial Crack Face Areas Table 7-7: Flaw Area Comparison Page 53

Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary As shown above in Table 7-7 [

] therefore, sufficient area has been removed in the Limit Load model to account for the area of the flaw and crack growth.

Since sufficient area has been removed and the limiting pressure exceeded 150% of the Design Pressure, the primary stress criteria in items 3.1(c) and 3.2(a)(3) of Code Case N-749 (Reference [3])

are satisfied.

8.0 CONCLUSION

S A fatigue and stress corrosion crack growth and fracture mechanics evaluation for the end-of-evaluation period flaw sizes of the postulated flaws in the as-left J-Groove weld and buttering CEDM penetration location No. 46 has been performed in the main body of the document. Additionally, a fracture mechanics evaluation for the limiting intermediate flaw sizes of the postulated flaws is performed in Appendix C.

Based on a combination of linear elastic and elastic-plastic fracture mechanics the postulated flaws are shown to be acceptable through the remaining service life of the plant scheduled to end in 2038 for a total of 17 years after the installation of the ANO Unit 2 CEDM nozzle repair utilizing the safety factors in Table 3-1, and the [ ] J-R Curve from [ ] as limited by the conditions outlined in Section 8.1 below.

8.1 Analysis Limitations for IDTB Repair

The minimum fluid temperature for performing [ ]

transients (described in Section 5.3) is [ ]

The maximum [ ] transient pressure when the fluid temperature is less or equal to

[ ] is [ ]

The maximum Cooldown transient pressure when the fluid temperature is less or equal to

[ ] is [ ]

Note that, per Section 5.2.2.4 of Reference [27], the low temperature overpressure protection (LTOP) lift setting is limited to 430 psig for RC fluid temperature less or equal to 220°F and therefore, [

] operations are protected from exceeding this pressure at the [ ] temperatures identified in the analysis limitations above.

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9.0 REFERENCES

1. [

]

2. ASME Boiler and Pressure Vessel Code,Section XI, Rules for Inservice Inspection of Nuclear Power Plant Components, 2007 Edition including Addenda through 2008.

3. Cases of the ASME Boiler and Pressure Vessel Code, Case N-749, Alternative Acceptance Criteria for Flaws in Ferritic Steel Components Operating in the Upper Shelf Temperature Range,Section XI, Division 1, 2012.

This Code Case is Conditionally Acceptable per Regulatory Guide 1.147, Revision 19 [4].

4. Regulatory Guide 1.147, Revision 19, Inservice Inspection Code Case Acceptability, ASME Section XI, Division 1, October 2019 (ADAMS No. ML19128A244).

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

6. T.L. Anderson, Fracture Mechanics - Fundamentals and Applications, CRC Press, 1991.

7. [

]

8. ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Facility Components, Division 1, 1992 Edition with no Addenda.

9. [

]

10. [ ]

11. [ ]

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

13. ASME Boiler and Pressure Vessel Code,Section III, Nuclear Power Plant Components, Division 1, 1968 Edition including Addenda through Summer 1970

14. Westinghouse Report, WCAP-18169-NP, Rev. 1, Arkansas Nuclear One Unit 2 Heatup and Cooldown Limit Curves for Normal Operation, June 2018.

15. [ ]

16. Regulatory Guide 1.161, Evaluation of Reactor Pressure Vessels with Charpy Upper-Shelf Energy Less than 50 ft-lb, June 1995.

17. ASTM E 185-21, Standard Practice for Design of Surveillance Programs for Light-Water Moderated Nuclear Power Reactor Vessels.

18. [

]

19. [

]

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20. Avalone, E.A., Baumeister, T., Sadegh, A.M., (Eds.) Marks Standard Handbook for Mechanical Engineers, Eleventh Edition, McGraw Hill.

21. [

]

22. [

]

23. A. L. Hiser and J. B. Terrell, Size Effects on J-R Curves for A-302B Plate, US NRC NUREG/CR-5265, January 1989.

24. ASM Handbook, Volume 1, Properties and Selection: Irons, Steels, and High-Performance Alloys, ASM International, 1990.

25. R. J., Stofanak, et al, Irradiation Damage Behavior of Low Alloy Steel Wrought and Weld Materials, Bettis Atomic Power Laboratory.

26. D. E. McCabe, E. T. Manneschmidt, and R. L., Swain, Ductile Fracture Toughness of Modified A 302 Grade B Plate Materials, US NRC NUREG/CR-6426, Volumes 1 and 2, January and February 1997.

27. Arkansas Nuclear One, Unit 2, Safety Analysis Report Amendment 30 (Redacted), April 2022 (ADAMS Accession No. ML22124A153).

28. [ ]

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary APPENDIX A: UPHILL SIDE FLAW EVALUATIONS This appendix presents the fatigue crack growth, SCC crack growth, and flaw evaluations for the postulated uphill side flaw.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary A.1 Flaw Growth Analysis of Position [ ] on the Uphill Side Table A-1: Fatigue Crack Growth for Transient [ ] (Uphill)

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary A.2 Flaw Growth Analysis of Position [ ] on the Uphill Side Table A-9: Fatigue Crack Growth for Transient [ ] (Uphill)

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary A.3 EPFM Evaluation of Position [ ] on the Uphill Side Table A-17: EPFM Evaluation [ ] (Uphill)

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Figure A-1: J-T Diagram [ ] (Uphill)

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary APPENDIX B: DOWNHILL SIDE FLAW EVALUATIONS This appendix presents the fatigue crack growth and flaw evaluations for the downhill side flaw.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table B-6: Fatigue Crack Growth for Transient [ ] (Downhill)

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table B-7: Fatigue Crack Growth for Transient [ ] (Downhill)

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary B.2 EPFM Evaluation of Position [ ] on the Downhill Side Table B-9: EPFM Evaluation [ ] (Downhill)

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary APPENDIX C: LEFM AND EPFM FLAW EVALUATION AT LIMITING INTERMEDIATE FLAW SIZES In addition to the LEFM and EPFM evaluations performed for the end-of-evaluation period flaw sizes in Sections 7.4 and 7.5 as required by ASME Section XI, Reference [2], and ASME Code Case N-749, Reference [3], this Appendix presents additional LEFM and EPFM flaw evaluations at limiting intermediate flaw sizes for the postulated flaws in the uphill and downhill sides.

Review of the maximum applied SIFs documented in Section A.1 and B.1 for the limiting crack front positions [ ] and [ ] on the uphill and downhill side, respectively, indicates that maximum applied SIF for all transients evaluated occurs after [ ] years of plant operation following the IDTB repair on the uphill side [ ] and after [ ] years of plant operation following the IDTB repair on the downhill side [ ] Furthermore, the minimum LEFM margins outlined in Section 3.4.1, for cases when the metal temperature is less than the upper shelf transition temperature of [ ]

defined in Section 3.4.2.1, also occurs on years [ ] and [ ] for the postulated flaws on the uphill and downhill side, respectively.

Sections C.1and C.2 in this Appendix contain the LEFM and EPFM evaluations at the limiting intermediate flaw sizes for the postulated flaws in the uphill and downhill sides following the same methodology outlined in the main body of the document.

C.1 LEFM Evaluation The results for the limiting uphill position [ ] and for the limiting downhill position [ ] are shown in Table C-1 and Table C-2, respectively. Review of the results of Table C-1 and Table C-2 indicates that, with few exceptions, the LEFM acceptance criteria are not met; however, in all cases shown, with the exception of the [ ] the temperature exceeds of [ ] and may therefore be analyzed based on EPFM.

For the [ ] cases, the LEFM results are not acceptable, and the temperature of [ ] does not meet the criteria for analysis by EPFM. Since the [

] cases are [ ] a temperature of 164°F will be considered and EPFM analysis will be performed. The [ ]

cases will be considered acceptable to meet the EPFM requirements provided that [

] are performed with a fluid temperature of [ ] or greater.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary For the [ ] cases evaluated on the uphill and downhill sides with the

[ ] the LEFM results are not acceptable for load steps [

] Per Table 5-7 of Reference [18],

these load steps correspond to [

]

The LEFM requirements at these [ ] load steps are considered met provided that the maximum transient pressure, when the fluid temperature is equal to or less than [ ] during [ ]

and equal to or less than [ ] during [ ] is [

]

Lastly, review of the results also indicates that the LEFM acceptance criteria are met for all cases where the transient fluid temperature or the crack tip metal temperature fall in between the temperatures of 1 and in which the fracture mode is in transition from LEFM to EPFM.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary C.2 EPFM Evaluation For the postulated cracks on the uphill and downhill sides, the EPFM evaluations will be performed at the limiting crack front positions at their limiting intermediate flaw sizes in accordance with the methodology described in Section 3.4.2 [

]

As discussed in the Section C.1, the limiting load steps of all transients in which the fluid temperature

[ ] may be evaluated using EPFM. Table C-3 provides the results of the EPFM evaluations for the limiting intermediate flaw size of crack front position [ ] on the uphill side. Table C-4 provides the results of the EPFM evaluations for the limiting intermediate flaw size of crack front position [ ]

on the downhill side. [

]

For the postulated cracks on both the uphill and the downhill sides, as shown in Table C-3 and Table C-4, all cases meet the EPFM acceptance criteria. [

] Details of the calculations for the limiting [ ] transient are provided for crack front position [ ] on the uphill side in Table C-5. Details of the calculations for the limiting

[ ] transient are provided for crack front position [ ] on the downhill side in Table C-6.

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table C-3: EPFM Results - Uphill [ ]

Table C-4: EPFM Results - Downhill [ ]

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Document No. 32-9357372-000 ANO-2 RVCH CEDM Penetration No. 46 IDTB Repair As-Left J-Groove Weld Analysis - Non-Proprietary Table C-5: EPFM Evaluation [ ] (Uphill) [ ]

Table C-6: EPFM Evaluation [ ] (Downhill) [ ]

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ENCLOSURE 2, ATTACHMENT 3 2CAN012302

[

] Document Number 51-9339414-001 (NON-PROPRIETARY)

Controlled Document 20004-026 (08/12/2020)

Framatome Inc.

Engineering Information Record Document No.: 51 - 9339414 - 001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Page 1 of 18

Controlled Document 20004-026 (08/12/2020)

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary 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 Pages/Sections Name and P/LP, R/LR, M, Prepared/Reviewed/

Title/Discipline Signature A-CRF, A Date Approved or Comments Roluf Andersen P All Materials Engineering Engineer I Ryan Hosler R All Materials Engineering Engineering Supervisor

Darren Wood A All Manager Engineering

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 Title (printed or typed) (printed or typed) Signature Date Mark Michaels Project Manager

Page 2

Controlled Document 20004-026 (08/12/2020)

Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Record of Revision Revision Pages/Sections/

No. Paragraphs Changed Brief Description / Change Authorization 000 All Original Issue. Proprietary information is marked by bold brackets. The corresponding proprietary document is 51-9338948-000.

001 As noted Appendix A added; Reference 2 updated.

Proprietary information is marked by bold brackets. The corresponding proprietary document is 51-9338948-001.

Page 3

Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Table of Contents Page SIGNATURE BLOCK ................................................................................................................................ 2 RECORD OF REVISION .......................................................................................................................... 3 LIST OF FIGURES ................................................................................................................................... 5 1.0 PURPOSE..................................................................................................................................... 6

2.0 BACKGROUND

............................................................................................................................ 6 2.1 Known Occurrences of Exposed Carbon/Low Alloy Steel Base Metal .............................. 9 3.0 ASSUMPTIONS .......................................................................................................................... 10 3.1 Justified Assumptions...................................................................................................... 10 3.2 Assumptions Requiring Verification................................................................................. 10 4.0 EVALUATION ............................................................................................................................. 11 4.1 Corrosion of Exposed Low Alloy Steel in the Modified Configuration ............................. 11 4.1.1 General Corrosion of Exposed Base Metal ...................................................... 11 4.1.2 Crevice Corrosion of Exposed Base Metal ....................................................... 12 4.1.3 Galvanic Corrosion of Exposed Base Metal ..................................................... 13 4.1.4 Stress Corrosion Cracking of Exposed Base Metal .......................................... 13 4.1.5 Hydrogen Embrittlement of Exposed Base Metal ............................................. 14 4.2 Corrosion of Alloy 690 and Alloy 52M ............................................................................. 14 4.3 [ ] ............................................................. 15

5.0 CONCLUSION

............................................................................................................................ 15

6.0 REFERENCES

............................................................................................................................ 16 APPENDIX A : IMPACT OF REPAIR CONTINGENCIES IN REFERENCE 2 ................................. A-1 Page 4

Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary List of Figures Page Figure 2-1: Current Configuration of CEDM Nozzle at ANO-2 (Reference 2).......................................... 7 Figure 2-2: IDTB CEDM Nozzle Repair Configuration (Reference 2) ...................................................... 8 Page 5

Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary 1.0 PURPOSE This document evaluates potential corrosion concerns arising from the final geometrical configuration of the inside diameter temper bead (IDTB) weld modification of the control element drive mechanism (CEDM) Nozzle 46 at Arkansas Nuclear One Unit 2 (ANO-2) (Reference 1). The evaluations performed herein are applicable for the life of the repair. The materials with potential corrosion concerns evaluated within this document include the exposed low alloy steel (LAS) of the reactor vessel closure head (RVCH) as well as the new materials, which include the Alloy 52M IDTB weld, the Alloy 690 replacement CEDM nozzle, the [ ] replacement CEDM nozzle guide, and the Alloy 52M fillet weld joining the replacement nozzle to the replacement guide. In evaluating the potential corrosion concerns, this document will provide an estimate of the total corrosion rate of the exposed LAS at the locations of interest affected by the modification. The only corrosion type that will not be evaluated in this document is PWSCC of the remaining Alloy 600 nozzle, which will be evaluated separately.

Revision 001 The purpose of Revision 001 is to discuss the impact of the repair contingencies in Reference 2. This is discussed in Appendix A.

2.0 BACKGROUND

Starting in 2000, several RVCH nozzles at U.S. pressurized water reactors (PWRs) have reported indications which have been attributed to primary water stress corrosion cracking (PWSCC). During the Fall 2021 outage (2R28), ultrasonic examination (UT) and surface dye penetrant testing (PT) revealed the presence of a surface breaking indication on the downhill side of the CEDM Penetration No. 46 on the RVCH of ANO-2. Due to the aforementioned conditions, Entergy Nuclear Corporation (Owner) contracted Framatome to repair RVCH penetration nozzle #46. The current configuration is shown in Figure 2-1 (Reference 2). Framatome will perform an IDTB weld modification of this nozzle, as shown in Figure 2-2 (Reference 2). The repair involves removal of the existing CEDM nozzle guide, roll expansion and machining of the Alloy 600 nozzle, application of the IDTB weld, rotary peening of the modified surface, and welding of the replacement nozzle guide. The repair configuration will leave portions of the LAS inside the RV head penetrations exposed to the primary reactor coolant. Note that Figure 2-1 and Figure 2-2 are for information only and the design specification and design drawings (References 1 and 2, respectively) are the official records of the design.

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Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Figure 2-1: Current Configuration of CEDM Nozzle at ANO-2 (Reference 2)

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Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Figure 2-2: IDTB CEDM Nozzle Repair Configuration (Reference 2)

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Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary 2.1 Known Occurrences of Exposed Carbon/Low Alloy Steel Base Metal The primary reactor coolant system (RCS), the pressurizer, reactor vessel, and the steam generator are clad with either a stainless steel or nickel-base alloy to prevent corrosion of the carbon or LAS base metal. Throughout the operating history of U.S. PWRs, there have been many cases where a localized area of the carbon or LAS base metal has been exposed to the primary coolant. Several such instances 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 Three Mile Island Unit 1 steam generator - Several tubes have separated within the tube-sheet area exposing the tube-sheet material to primary coolant. (LER 289-1990-005) 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 mis-drilled tube-sheet hole in the upper tube-sheet of one of the steam generators, during plugging operation in 1991, led to exposure of a small area of unclad tube-sheet to primary coolant. (Note: This area of the tube-sheet has since been patched and is no longer exposed to coolant.)

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

1993 SONGS-Unit 2 hot leg nozzle - A repair to a hot leg nozzle was completed during the 1993 outage at the SONGS Unit 2. This repair consisted of replacing a section of the existing Alloy 600 nozzle with a new nozzle section fabrication from Alloy 690. A gap approximately [ ] wide exists between the two nozzle sections where the carbon steel base metal is exposed to the primary coolant. Verbal communication with SONGS personnel indicated that the hot leg nozzle containing this repair was removed and the exposed carbon steel examined.

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

[ ] 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) 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 AREVA IDTB half-nozzle repairs to the Harris CRDM nozzle penetrations. (LER 400-2013-001)

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Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary In each of these instances, carbon or LAS base metal was exposed to primary coolant in a localized area. Each plant returned to normal operation with the base metal exposed; in the case of Yankee-Rowe, the vessel operated for roughly 30 years with the base metal exposed. There are no known cases of exposed LAS resulting in reduced functionality of the pressure boundary. The operating experience listed above is expected to be applicable to ANO-2 since all are U.S. PWRs, which generally have similar environments (i.e., water temperature and chemistry).

3.0 ASSUMPTIONS 3.1 Justified Assumptions

1. The methodology used to calculate the combined corrosion rate in Section 4.1.1.2 is conservative relative to any typical variations in the environmental conditions of the primary coolant that may occur at ANO-2.

This is based on several factors. First, the laboratory test conditions reported in Reference 18 are intended to be representative of typical PWR operation. In addition, three major layers of conservatism are built into the methodology:

While plant startup and shutdown are briefly expected to have differing conditions, this is not expected to be a concern. Per Reference 17, the corrosion rate for these conditions is 0.017 ipy, [

] However, the intermediate conditions (350°F) resulting in the faster rate will only occur for a brief duration. Given all of the conservatisms discussed above, the differing conditions during plant startup and shutdown will remain bound by the conservative combined corrosion rate in Section 4.1.1.2.

3.2 Assumptions Requiring Verification No assumptions requiring verification have been used in this evaluation.

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Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary 4.0 EVALUATION 4.1 Corrosion of Exposed Low Alloy Steel in the Modified Configuration Several types of corrosion can occur when carbon and LAS base metal are exposed to primary coolant. During operating conditions, the primary coolant is deaerated at high temperatures (343°C [650°F] design temperature (Reference 1) depending on the location within the RCS. During shutdown conditions, the primary coolant temperature approaches 21°C (70°F) and may become aerated and/or stagnant depending on the location within the RCS. The following sections discuss the possible corrosion mechanisms for the exposed LAS base metal at the modified location depicted in Figure 2-2.

4.1.1 General Corrosion of Exposed Base Metal General corrosion is defined as a type of corrosion attack (deterioration) which proceeds more or less uniformly over an exposed surface without appreciable localization (Reference 4). Stainless steels and nickel-based alloys (e.g., wrought Type 304, Type 316, Alloy 600, and Alloy 690 and their equivalent weld metals) are essentially resistant to general corrosion in a PWR environment due to their passive protective surface layer. Carbon and LAS, however, may be susceptible to general corrosion depending on the service environment. The major factors affecting the general corrosion susceptibility of LAS are temperature, fluid velocity, water chemistry, and time.

The general corrosion rates of carbon and LAS in aerated and deaerated conditions are discussed in the subsections below.

4.1.1.1 Oxygen Concentration in the Modified Area

[

] Note that there may be some variations in the water chemistry at the exposed LAS due to crevice conditions that could affect the corrosion rate, but this is addressed in Section 4.1.2 4.1.1.2 General Corrosion Rate Many investigators have reported corrosion rates of carbon and LAS in various environments (References 7, 8, 9, 10, 11, 12, 13, 14, 15, and 16). In several instances, the corrosion rates for carbon and LAS have been observed to be similar in PWR environments; this data is applicable to carbon and LAS materials such as A-302, SA-533, and SA-516 plates (References 7, 9, 10, 14). The ANO-2 RVCH LAS is SA-533 Gr. B, Cl. 1.

The Electric Power Research Institute (EPRI) has published a handbook on boric acid corrosion (Reference 17).

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. In one evaluation, ASTM A302 Grade B plate was exposed to primary coolant in aerated and deaerated conditions (Reference 18). It was shown that under deaerated conditions (i.e., during operation), the corrosion rate depended on temperature, fluid velocity, boric acid concentration, and time (Reference 18). The corrosion rate was determined to be 0.0762 Page 11

Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary millimeters/year (mmy) (0.003 inch/year [ipy]) at the maximum velocity tested (11 m/sec [36 ft/sec]), which is expected to be faster than the maximum flow velocity in the vicinity of the modification. This was the maximum corrosion rate reported. Under static conditions (i.e., stagnant) at 343°C [650°F], a maximum corrosion rate of 0.0229 mmy (0.0009 ipy) was reported. In this same study at shutdown conditions (aerated, at low temperature),

the maximum corrosion rate was determined to be 0.0381 millimeter (0.0015 inch) for a two-month shutdown, or 0.229 mmy (0.009 ipy) (Reference 18).

4.1.1.3 General Corrosion Rate in the HAZ 4.1.1.4 Long Term General Corrosion The initial corrosion rate for the exposed LAS is conservatively estimated to be [ ] assuming the conditions described in Section 4.1.1.2. [ ] the rate will decrease significantly as corrosion occurs causing the formation of an oxide film. To a lesser degree, the corrosion rate will also decrease over time as corrosion products fill the gap between the nozzle and the bore. The gap between the LAS RVCH and the replacement nozzle, depicted on Figure 2-2, is expected to eventually become packed with iron oxide corrosion products such as Fe3O4 and Fe2O3. The long-term release of Fe corrosion products in the RCS is expected to be negligible.

4.1.2 Crevice Corrosion of Exposed Base Metal The environmental conditions in a crevice can become aggressive with time and can cause accelerated local corrosion. The geometry of the gap between the RVCH and replacement nozzle could create the conditions for crevice corrosion. Experiments were conducted to determine the crevice corrosion rate of LAS. The results indicate that the crevice corrosion rate for both aerated and deaerated conditions is less than the respective general corrosion rate (References 12, 18). Operating experience from PWRs shows that crevice corrosion is not normally a problem in PWR systems with expected low oxygen contents (Reference 14).

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Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Several corrosion studies have examined crevice corrosion in the gaps between [

]

Based on previous experiments, crevice corrosion is not expected to be a concern for this modification [

]

4.1.3 Galvanic Corrosion of Exposed Base Metal Galvanic corrosion may occur when two dissimilar metals in contact are exposed to a conductive solution or coupled together. The three essential components to galvanic corrosion are 1) materials possessing different surface potential, 2) a common electrolyte, and 3) a common electrical path. The larger the potential difference between the metals, the greater the likelihood of galvanic corrosion. Low alloy and carbon steel are more anodic than stainless steels and nickel-base alloys (Reference 22) 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. In one test, carbon steel specimens were coupled and uncoupled to stainless steel and exposed to simulated reactor shutdown conditions. The corrosion rates while coupled and uncoupled were determined to be similar (Reference 17).

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 (Reference 18).

Austenitic stainless steels, such as Type 304, have approximately the same corrosion potential as nickel-base alloys such as Alloy 690. Therefore, galvanic corrosion studies of LAS and stainless steel give insight into the galvanic corrosion of LAS and nickel-base alloys. Specimens made from 5% chromium 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 (Reference 16).

Additionally, results of the NRCs boric acid corrosion test program have shown that the galvanic difference between ASTM A533 Grade B (LAS), 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 (Reference 23).

Galvanic corrosion between the exposed LAS and Alloy 600, Alloy 690, or their weld metals is not expected to be a concern for the proposed modification.

4.1.4 Stress Corrosion Cracking of Exposed Base Metal Stress corrosion cracking (SCC) can only occur when the following three conditions are present:

x A susceptible material x A tensile stress x An aggressive environment Page 13

Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Under normal PWR conditions (deaerated), primary water is not a particularly aggressive environment for LAS unless a departure from normal operating conditions occurs (Reference 24). This service environment (i.e.,

deaerated; and low sulfate and chlorides) does not generally support localized corrosion of LAS; therefore the likelihood of a pit or notch forming which would contribute a stress concentrator or SCC initiation site is negligible. Extensive experience with exposed LAS in PWRs (see Section 2.1 of this document) has not resulted in any reported SCC. Overall, SCC in exposed LAS is not expected to be a concern for the IDTB weld modification.

4.1.5 Hydrogen Embrittlement of Exposed Base Metal Hydrogen embrittlement occurs when a materials properties are degraded due to the presence of hydrogen. This type of damage usually occurs in combination with a stress; residual, applied, or otherwise. Hydrogen embrittlement is typically observed in high pressure hydrogen environments and in deformed metals. Hydrogen embrittlement is characterized by ductility losses and lowering of the fracture toughness (Reference 4). High pressure hydrogen environments are not typical of PWR systems and are defined as an environment with approximately 34 MPa to 69 MPa (5,000-10,000 psi) (Reference 25). Although hydrogen is added to PWR water to scavenge oxygen (see Section 4.1.1.1 of this report), the primary contributor of hydrogen diffusion into the LAS is the corrosion process. Corrosion tests on LAS in deaerated boric acid solutions indicated that the maximum concentration of the hydrogen in the LAS from the corrosion process was less than 2 ppm and did not increase with time (Reference 18). The quantity of hydrogen that may accumulate at locations within the coolant system is not expected to induce hydrogen embrittlement in materials at these locations. Therefore, hydrogen embrittlement is not expected to be a concern for the LAS exposed to primary water.

4.2 Corrosion of Alloy 690 and Alloy 52M Alloy 52M (Alloy 52 modified) is the specified IDTB weld material and fillet weld material for the modification of the nozzle (Reference 1, 2). Information regarding the corrosion of Alloy 690 (the associated base metal to Alloy 52M) and Alloy 52 (the base Alloy 52 not containing some of the alloying elements of Alloy 52M) will also be presented. This will provide a better understanding of the potential corrosion concerns of Alloy 52M. The corrosion resistance of Alloy 52M is expected to be similar to that of Alloy 52 and Alloy 690. The difference between Alloy 52 and 52M is minor alloying elements for enhanced weldability. The chromium content, which provides the corrosion resistance of the material, is similar. The corrosion resistance of Alloy 690 has been extensively studied as a result of numerous PWSCC failures in mill annealed Alloy 600 in primary water environments. As a result of Alloy 600 failures, Alloy 690 has been chosen by the nuclear industry as the replacement material for Alloy 600 components. A comprehensive review 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 deoxygenated water) and secondary coolant environments. The first Alloy 690 steam generator went online in May 1989 with no reported failures due to environmental degradation as of the date of that publication (August 1997) (Reference 26). No environmental degradation of Alloy 690 or its related weld metals has been reported since August 1997. More specifically, industry experience has shown that crevice and general corrosion of austenitic nickel-base materials are not expected to be of great concerns in typical PWR conditions (Reference 27).

Alloy 52M was tested (not as a part of this work scope) in accelerated corrosion conditions by testing 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 (10 psi) with a total steam pressure of 20 MPa (2.9 ksi); this environment has been previously used to accelerate the simulated PWSCC of nickel-base alloys. After a cumulative exposure of 2051 hours0.0237 days 0.57 hours 0.00339 weeks 7.804055e-4 months (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. Stress corrosion cracks initiated in the also-tested Alloy 182 welds in exposure times less than one-fifth the total exposure time of the Page 14

Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Alloy 52M specimens (Reference 28). This study, along with many others (examples in References 29, 30, and 31) indicate that the Alloy 52M weld metal in the proposed modification has a high resistance to PWSCC.

SCC test data comparing results between Alloy 690 and Alloy 600 is available in both aerated and deaerated high temperature water. [

] Based on the above studies and the excellent operating experience, Alloy 690 [

]

4.3 [ ]

5.0 CONCLUSION

This document evaluates the potential corrosion mechanisms that may affect the final geometrical configuration of the exposed LAS in the proposed ANO-2 RVCH penetration modification configuration, shown in Figure 2-2.

Based on this evaluation, the modification is found acceptable with respect to its effect on corrosion of the affected material (as detailed below).

Galvanic corrosion, hydrogen embrittlement, SCC, and crevice corrosion are not expected to be a concern for the exposed LAS base metal resulting from the IDTB modification process. General corrosion of the exposed LAS base metal will occur. Based on industry data, the general corrosion rate of the LAS due to the nozzle modification is conservatively estimated to be [ ]

Page 15

Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary Extensive operating experience and laboratory testing of Alloy 52 and its associated base metal (Alloy 690) indicate that the Alloy 52M weld metal and Alloy 690 in the modification has a high resistance to PWSCC and is not susceptible to any other forms of degradation in the PWR environment.

[ ]

6.0 REFERENCES

References identified with an (*) are maintained within Entergys 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. [

]

2. [

]

3. U.S. Nuclear Regulatory Commission, NUREG/CR-6923, Expert Panel Report on Proactive Materials Degradation Assessment.

4. ASM Metals Handbook, Eleventh Edition, Volume 13A Corrosion, 2003.

5. B. Pastina, 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) 309-318.

6. P. Scott, A Review of Irradiation Assisted Stress Corrosion Cracking, Journal of Nuclear Materials, 211 (1994) 101-122.

7. Whitman, G. D. et. al., A Review of Current Practice in Design, Analysis, Materials, Fabrication, Inspection, and Test, ORNL-NSIC-21, ORNL, December 1967.

8. Vreeland, D. C. et. al., Corrosion of Carbon and Low-Alloy Steels in Out-of-Pile Boiling Water Reactor Environment, Corrosion, v17, June 1961, p. 269.

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

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

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

12. 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.

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

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

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

Page 16

Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary

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

17. *Boric Acid Corrosion Guidebook, Revision 2: Managing Boric Acid Corrosion Issues at PWR Power Stations, EPRI, Palo Alto, CA: 2012. 1025145.

18. 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.

19. Ferguson, M., Examination of 24-inch Tube Sheet Assembly from the 37-Tube OTSG, LR:68:2218-05:1, Babcock & Wilcox, AREVA NP, Inc. Proprietary, Alliance, Ohio, January 18, 1968.

20. 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, Alliance, Ohio, October 26, 1981.

21. MRP-163, Materials Reliability Program: Reactor Vessel head Boric Acid Corrosion Testing (MRP-163) - Task 1: Stagnant and Flow Primary Water Tests, December 2005.

22. ASM Metals Handbook, Ninth Edition, Volume 13 Corrosion, 1987.

23. 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.

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

25. Gray, H.R., Testing for Hydrogen Environment Embrittlement: Experimental Variables, STP543, 1974, ASTM.

26. 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 10-14, 1997, ANS.

27. Fyfitch, S. (2012) Corrosion and Stress Corrosion Cracking of Ni-Base Alloys. In: Konings R.J.M., (ed.)

Comprehensive Nuclear Materials, volume 5, pp. 69-92, Amsterdam: Elsevier.

28. 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 10-14, 2003, ANS.

29. Sedriks, A.J., et. al., Inconel Alloy 690 - A New Corrosion Resistant Materials, Boshoku Gijutsu, Japan Society of Corrosion Engineering, v28, No. 2, pp. 82-95, 1979.

30. Brown, C.M., and Mills, W.J., Effect of Water on Mechanical Properties and Stress Corrosion Behavior of Alloy 600, Alloy 690, EN82H Welds, and EN52 Welds, Corrosion, v55(2), February 1999.

31. Mills, W.J., and Brown, C.M., Fracture Behavior of Nickel-Based Alloys in Water, Ninth International Conference on Environmental Degradation of Materials in Nuclear Power Systems - Water Reactors, August 1-5, 1999, TMS.

32. MRP 2008-018, MRP White Paper on Stress Corrosion Cracking of Stainless Steel Components in Pressurized Water Reactors Primary Water Environments, December 2007.

33. [

]

Page 17

Controlled Document Document No.: 51-9339414-001 Corrosion Evaluation of ANO-2 RVCH CEDM IDTB Weld Nozzle Penetration Repair - Non Proprietary APPENDIX A: IMPACT OF REPAIR CONTINGENCIES IN REFERENCE 2 Several repair contingences have been developed by Framatome in Reference 2. These contingencies will be discussed in the following sections.

A.1 Shallow Cut Contingency

[

] Therefore, this contingency will not have an effect on the conclusions of Revision 000 of this document (see Section 5.0).

A.2 Overbore Contingency

[

] this contingency will not have an effect on the conclusions of Revision 000 of this document (see Section 5.0).

Page A-1

ENCLOSURE 2, ATTACHMENT 4 2CAN012302

[ ] Document Number 51-9358148-000 (NON-PROPRIETARY)

20004-026 (08/12/2020)

Framatome Inc.

Engineering Information Record Document No.: 51 - 9358148 - 000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary Page 1 of 12

20004-026 (08/12/2020)

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary 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 Pages/Sections Name and P/LP, R/LR, M, Prepared/Reviewed/

Title/Discipline Signature A-CRF, A Date Approved or Comments Stacy Yoder LP All Engineer IV Sarah Davidsaver LR All Advisory Engineer

Ryan Hosler A All Supervisory Engineer

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 Title (printed or typed) (printed or typed) Signature Date N/A N/A Page 2

20004-026 (08/12/2020)

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary Record of Revision Revision Pages/Sections/

No. Paragraphs Changed Brief Description / Change Authorization 000 All Original Issue. Proprietary information is marked by square brackets.

The corresponding proprietary document is 51-9352242-000.

Page 3

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary Table of Contents Page SIGNATURE BLOCK ................................................................................................................................ 2 RECORD OF REVISION .......................................................................................................................... 3 LIST OF FIGURES ................................................................................................................................... 5 1.0 PURPOSE..................................................................................................................................... 6

2.0 BACKGROUND

............................................................................................................................ 6 3.0 ASSUMPTIONS ............................................................................................................................ 9 4.0 CALCULATIONS AND EVALUATIONS RESULTS ...................................................................... 9 4.1 ASME Section III Evaluation ............................................................................................. 9 4.2 As-Left J-Groove Flaw Evaluation ..................................................................................... 9 4.3 Weld Anomaly Flaw Evaluation ....................................................................................... 10 4.4 Primary Water Stress Corrosion Cracking Evaluation ..................................................... 10

5.0 CONCLUSION

............................................................................................................................ 11

6.0 REFERENCES

............................................................................................................................ 12 Page 4

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary List of Figures Page Figure 2-1: Original Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 (References [2, 8]) .................................................................................................................. 7 Figure 2-2: Modified Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 (References [2, 8]) .................................................................................................................. 8 Page 5

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary 1.0 PURPOSE The purpose of this document is to provide a summary of the calculations and evaluations performed to establish the life expectancy of the inner diameter temper bead (IDTB) weld repair on Control Element Drive Mechanism (CEDM) Nozzle Penetration No. 46 in the reactor vessel closure head (RVCH) of Arkansas Nuclear One Unit 2 (ANO-2).

The proprietary version of this document is 51-9352242-000.

2.0 BACKGROUND

During the Fall 2021 outage (2R28) ultrasonic examination (UT) and surface dye penetrant testing (PT) revealed the presence of a surface breaking indication on the downhill side of the CEDM Nozzle Penetration No. 46 in the RVCH of ANO-2. Due to the aforementioned conditions, Entergy Nuclear Corporation (Owner) contracted Framatome to repair CEDM Nozzle Penetration No. 46 [1].

The original configuration of CEDM Nozzle Penetration No. 46 is shown in Figure 2-1 [2, 8]. Framatome performed an IDTB weld repair of this nozzle, as shown in Figure 2-2 [2, 8]. The repair involved removal of the existing CEDM nozzle guide, roll expansion and machining of the Alloy 600 nozzle, application of the IDTB weld, rotary peening of the modified surface, and welding of the replacement nozzle guide. The repair configuration left portions of the low alloy steel (LAS) inside the RV head penetrations exposed to the primary reactor coolant. Note that Figure 2-1 and Figure 2-2 are for information only and the design specification and design drawings (References [1] and [2], respectively) are the official records of the design.

Analyses and evaluations have been performed to determine the minimum life expectancy of the CEDM Nozzle Penetration No. 46 repair. They include an ASME Section III code evaluation (which considered general corrosion), a J-Groove flaw evaluation, a weld anomaly flaw evaluation, and a primary water stress corrosion cracking (PWSCC) life evaluation. The general description of each analysis/evaluation and their respective conclusions are summarized below.

Page 6

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary Figure 2-1: Original Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 (References [2, 8])

Page 7

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary Figure 2-2: Modified Configuration of CEDM Nozzle Penetration No. 46 at ANO-2 (References [2, 8])

Page 8

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary 3.0 ASSUMPTIONS No justified assumptions or assumptions requiring verification are made in this document.

4.0 CALCULATIONS AND EVALUATIONS RESULTS The following sections outline and summarize the results of the various calculations and evaluations performed to quantify the expected life of the IDTB weld repair on CEDM Nozzle Penetration No. 46 at ANO-2.

4.1 ASME Section III Evaluation An analysis of primary plus secondary stresses and fatigue was performed to qualify the ANO-2 CEDM Nozzle Penetration No. 46 repair to the applicable requirements of the Design Specification [1] in accordance with NB-3000 of the ASME Code Section III Subsection NB, 1992 Edition with no Addenda and Code Case N-638-7 [3].

Primary stresses for the ANO-2 CEDM Nozzle Penetration No. 46 repair were previously justified in Reference

[4].

The corrosion evaluation referenced within the Section III analysis determined that the general corrosion rate of the exposed LAS of the RVCH after the ANO-2 CEDM Nozzle Penetration No. 46 repair is determined to be

[ ] [5]. This small amount of corrosion volume lost has negligible impact on the response of the ANO-2 CEDM Nozzle Penetration No. 46 repair and is therefore acceptable for the life of repair.

This analysis demonstrated that the ANO-2 CEDM Nozzle Penetration No. 46 repair satisfies the ASME code primary stress and primary plus secondary stress requirements, as well as the criteria to protect against fatigue failure. The analysis concluded that the fatigue life of the IDTB weld repair is calculated as more than 17 years after the repair has been implemented.

4.2 As-Left J-Groove Flaw Evaluation A fracture mechanics analysis was performed on the ANO-2 CEDM Nozzle Penetration No. 46 repair to justify a postulated flaw remaining in the original nozzle-to-RVCH weld (as-left J-Groove weld) [6]. It is postulated that a radial-axial corner flaw exits through the entire J-Groove weld and buttering. This document complements previous flaw evaluation work that supported a one cycle justification of plant operation.

A fatigue crack growth and fracture mechanics evaluation of the postulated flaw in the as-left J-Groove weld and buttering at ANO-2 CEDM Nozzle Penetration No. 46 was performed. Based on a combination of linear elastic and elastic-plastic fracture mechanics analyses, the postulated flaws are shown to be acceptable for the remaining life of the plant scheduled to end in 2038 for a total of 17 years after the IDTB repair utilizing the safety factors listed in Table 3-1 of Reference [6], and the applicable J-R Curve from [ ] as limited by the conditions outlined below.

Analysis Limitations for IDTB repair:

x The minimum fluid temperature for performing the [ ] is

[ ]

x The maximum [ ] transient pressure when the fluid temperature is less than or equal to

[ ] is [ ]

x The maximum [ ] transient pressure when the fluid temperature is less than or equal to

[ ] is [ ]

Page 9

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary Note that the low temperature overpressure protection (LTOP) lift setting is limited to 430 psig for reactor coolant fluid temperature less or equal to 220°F and therefore, [ ] operations are protected from exceeding this pressure at the [ ] temperatures identified in the analysis limitations above.

4.3 Weld Anomaly Flaw Evaluation A fracture mechanics evaluation of a postulated weld anomaly for the ANO-2 CEDM ITDB repair weld at penetration No. 46 was performed [7]. The analysis evaluates a postulated 0.100 inch weld anomaly characterized as a linear defect extending into the IDTB weld in any direction from the triple point locations, where there is a confluence of three materials:

x Upper triple point location is defined as the intersection of the RVCH LAS base material, the existing CEDM nozzle, and the Alloy 52M IDTB weld.

x Lower triple point location is defined as the intersection of the RVCH LAS base material, the Alloy 690 replacement CEDM nozzle, and the Alloy 52M IDTB weld.

Flaw growth is calculated for several potential propagation paths from the time of IDTB weld installation in 2021 through 60 years of operation in 2038, for a total of 17 years. Flaw acceptance is based on the ASME B&PV Code, 2007 Edition with 2008 Addenda,Section XI, IWB-3613 for acceptance criteria based on applied stress intensity factor and IWB-3642 for limit load.

The results of the analyses demonstrate that a postulated 0.100 inch weld anomaly in the CEDM IDTB weld is acceptable from the time of IDTB weld installation in 2021 through 60 years of operation in 2038, for a total of 17 years. The minimum fracture toughness margins for flaw propagation are acceptable. The limit load analysis performed considering the ductile weld repair material along the horizontal flaw propagation paths shows that for the postulated circumferential and axial flaws, the minimum margin on allowable stress is acceptable. Fracture toughness margins have also been demonstrated for the postulated cylindrical flaws. Also, for the cylindrical flaws it is shown that the applied shear stress for the remaining ligament is less than the allowable shear stress per NB-3227.2.

Analysis Limitations for IDTB repair:

x The minimum fluid temperature for performing [ ]

x The maximum [ ] transient pressure when the fluid temperature is less or equal to [

]

x The maximum [ ] transient pressure when the fluid temperature is less or equal to [

]

Note that the LTOP lift setting is limited to 430 psig and therefore, [ ] operations are protected from exceeding this pressure at the [ ] temperatures identified in the limitations above.

4.4 Primary Water Stress Corrosion Cracking Evaluation A PWSCC evaluation was performed on the remaining American Society of Mechanical Engineers (ASME) SB-166 (Alloy 600) nozzle material affected by the repair, after performance of the CEDM Nozzle Penetration No. 46 IDTB weld repair (with rotary peening surface remediation) at ANO-2 [8]. This evaluation considered the CEDM Nozzle Penetration No. 46 in the as-modified condition with rotary peening remediation for typical, shallow cut, and overbore configurations.

Page 10

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary The areas of interest for this evaluation were 1) [

] For the three configurations, it is expected that any initiation of PWSCC within the CEDM nozzle will be eliminated due to the addition of the compressive stress layer; however, further analysis will need to be conducted if an inspection interval relief is to be justified according to MRP-335.

With the added compressive stress layer from rotary peening surface remediation, crack initiation from PWSCC is not expected due to the removal of sustained tensile stress, which is one of the three synergistic components of stress corrosion cracking.

5.0 CONCLUSION

Based on the calculations and evaluations documented above, the life assessment summary for the CEDM Nozzle Penetration No. 46 repair at ANO-2 is as follows:

x The ANO-2 CEDM Nozzle Penetration No. 46 repair meets the requirements of ASME Section III, and the calculated fatigue life of the IDTB weld repair is more than 17 years after the repair has been implemented.

x The as-left J-Groove flaw evaluation is acceptable through the remaining life of the plant scheduled to end in 2038 for a total of 17 years after the IDTB repair utilizing the safety factors, and the applicable J-R Curve from [ ] as limited by the conditions outlined below.

Analysis Limitations for IDTB repair:

o The minimum fluid temperature for performing the [ ] is

[ ]

o The maximum [ ] transient pressure when the fluid temperature is less than or equal to

[ ] is [ ]

o The maximum [ ] transient pressure when the fluid temperature is less than or equal to [ ] is [ ]

Note that the low temperature overpressure protection (LTOP) lift setting is limited to 430 psig for reactor coolant fluid temperature less or equal to 220°F and therefore, [ ] operations are protected from exceeding this pressure at the [ ] temperatures identified in the analysis limitations above.

x A triple point weld anomaly postulated to be 0.100 inch is acceptable for 17 years after the repair based on the ASME B&PV Code, 2007 Edition with 2008 Addenda,Section XI, IWB-3613 for acceptance criteria based on applied stress intensity factor and IWB-3642 for limit load.

Analysis Limitations for IDTB repair:

o The minimum fluid temperature for performing [

]

o The maximum [ ] transient pressure when the fluid temperature is less or equal to

[ ]

Page 11

Document No.: 51-9358148-000 ANO-2 CEDM Penetration 46 Modification Assessment Summary - Non-Proprietary o The maximum [ ] transient pressure when the fluid temperature is less or equal to

[ ]

Note that the LTOP lift setting is limited to 430 psig and therefore, [ ]

operations are protected from exceeding this pressure at the [ ] temperatures identified in the limitations above.

x The ANO-2 CEDM Nozzle Penetration No. 46 repair estimates with the added compressive stress layer from rotary peening surface remediation Nozzle Penetration No. 46 is not expected to experience crack initiation from PWSCC. For the three configurations, it is expected that any initiation of PWSCC within the CEDM nozzle will be eliminated due to the addition of the compressive stress layer; however, further analysis will need to be conducted if an inspection interval relief is to be justified according to MRP-335.

Therefore, the overall life of the ANO-2 CEDM Nozzle Penetration No. 46 repair with a compressive stress layer from rotary peening surface remediation is 17 years after the repair has been implemented.

6.0 REFERENCES

1. Framatome Inc. Document 08-9338577-003, [ ]

2. Framatome Inc. Drawing 02-9338578-E-002, [

]

3. Framatome Inc. Calculation 32-9348826-002, [

]

4. Framatome Inc. Calculation 32-9338944-001, [

]

5. Framatome Inc. Document 51-9338948-001, [

]

6. Framatome Inc. Calculation 32-9352384-001, [

]

7. Framatome Inc. Calculation 32-9352239-001, [

]

8. Framatome Inc. Document 51-9338718-001, [

]

Page 12

ENCLOSURE 2, ATTACHMENT 5 2CAN012302

[ ]

Document Number 32-9354538-002 (NON-PROPRIETARY)

0402-01-F01 (Rev. 021, 03/12/2018)

PROPRIETARY CALCULATION

SUMMARY

SHEET (CSS)

Document No. 32 - 9354538 - 002 Safety Related: Yes No Title ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP PURPOSE AND

SUMMARY

OF RESULTS:

PURPOSE:

The objective of this task is to perform an ASME Section III Code qualification (Reference [1]) of the Arkansas Nuclear One Unit 2 (ANO-2) Control Element Drive Mechanism (CEDM) half nozzle repair for penetration #46 using requirements given in the Design Specification (Reference [3]) and geometry based on Reference [4] and Reference [6]. The half nozzle repair uses the Framatome IDTB weld process (Inner Diameter Temper Bead).

Additional background information can be found in Section 1.0.

Primary stresses for the half-nozzle modification have already been justified by Reference [7] and it is added in Appendix C; therefore, this calculation only addresses primary plus secondary stresses in accordance with NB-3222.2 and fatigue in accordance with NB-3222.4(e)(5) per Reference [1]. The scope of this analysis includes the new modification (IDTB weld and replacement nozzle) and includes the local Reactor Vessel Closure Head (RVCH) at the repaired penetration. The new CEDM nozzle guide and the existing J-groove weld are not within the scope as these items are not pressure boundary.

SUMMARY

OF RESULTS:

The calculations herein, along with the primary stress evaluation in Reference [7], demonstrate that the CEDM IDTB weld repair meets the stress requirements of Section III of the ASME Code (Reference [1]). The fatigue life of the IDTB weld repair is calculated as [ ] The detailed summary of results is listed in Section 7.0.

The Proprietary version of this document is 32-9348826-002.

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, THE DOCUMENT CONTAINS AP 0402-01 requires that justification be provided.

ASSUMPTIONS THAT SHALL BE THE FOLLOWING COMPUTER CODES HAVE BEEN USED IN THIS DOCUMENT: VERIFIED PRIOR TO USE CODE/VERSION/REV CODE/VERSION/REV Yes ANSYS 19.2 No Page 1 of 99

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 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 P/R/A/M (printed or and Pages/Sections typed) Signature LP/LR Date Prepared/Reviewed/Approved Brady Cameron

P All Engineer II

Don Kim

R All Advisory Engineer Tomas Straka

M All Advisory Engineer

Dave Skulina

Supervisory A All

Engineer 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 Title (printed or typed) (printed or typed) Signature Date Comments N/A Page 2

0402-01-F01 (Rev. 021, 03/12/2018)

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Record of Revision Revision Pages/Sections/Paragraphs No. Changed Brief Description / Change Authorization 000 All Initial Release. The Content of this document is identical to 32-9348826-000, except that proprietary information is redacted.

001 Pages 1-3 Updated for Rev. 001.

Section 4.2 Additional information redacted.

Table B-1 Two fracture files (Temp.sav and TempScalar.sav) removed from table.

002 Pages 1-3 Updated for Rev. 002.

Pages 7, 52, 62, 63 Additional information redacted.

Pages 6, 13, 15, 16, 17, 51, 53, Previous redacted information unredacted.

59, 60 Table 5-20 Editorial change to load column in table.

Table 5-9 Grammatical change to note.

Page 3

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table of Contents Page SIGNATURE BLOCK ................................................................................................................................ 2 RECORD OF REVISION .......................................................................................................................... 3 LIST OF TABLES ..................................................................................................................................... 6 LIST OF FIGURES ................................................................................................................................... 8

1.0 BACKGROUND

........................................................................................................................... 10 2.0 ANALYTICAL METHODOLOGY .................................................................................................10 3.0 ASSUMPTIONS .......................................................................................................................... 10 3.1 Unverified Assumptions................................................................................................................... 10 3.2 Justified Assumptions...................................................................................................................... 11 3.3 Modeling Simplifications .................................................................................................................. 11 4.0 DESIGN INPUTS ........................................................................................................................ 11 4.1 Code Classification.......................................................................................................................... 11 4.2 Geometry ......................................................................................................................................... 11 4.3 Materials .......................................................................................................................................... 13 4.3.1 Material Properties ............................................................................................................ 13 4.3.2 ASME Code Allowable Stresses....................................................................................... 17 4.4 Loads ............................................................................................................................................... 17 4.4.1 Design Loads .................................................................................................................... 17 4.4.2 Operating Transient Loads ............................................................................................... 17 4.4.3 External Loads .................................................................................................................. 24 5.0 CALCULATIONS ......................................................................................................................... 25 5.1 External Loads ................................................................................................................................ 25 5.2 Finite Element Model....................................................................................................................... 26 5.2.1 Boundary Conditions ........................................................................................................ 28 5.3 Design Condition ............................................................................................................................. 32 5.4 Thermal Analysis ............................................................................................................................. 34 5.5 Structural Analysis........................................................................................................................... 37 5.6 ASME Code Evaluation ................................................................................................................... 47 5.6.1 Primary Stress Criteria ......................................................................................................51 5.6.2 Primary Plus Secondary Stress and Fatigue Usage Criteria ............................................ 51 5.6.3 Corrosion Evaluation ........................................................................................................ 56 5.7 Justification of Dissimilar Materials of the Replacement Guide and Replacement Nozzle ............. 57 6.0 COMPUTER USAGE .................................................................................................................. 58 Page 4

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table of Contents (continued)

Page 6.1 Software .......................................................................................................................................... 58 6.2 Computer Files ................................................................................................................................ 58 7.0 RESULTS & CONCLUSIONS ..................................................................................................... 62

8.0 REFERENCES

............................................................................................................................ 63 APPENDIX A : TRANSIENT TEMPERATURE AND THERMAL GRADIENT PLOTS .......................... 64 APPENDIX B : STRESSES FOR FRACTURE MECHANICS ANALYSIS ............................................ 79 APPENDIX C : PRIMARY STRESS EVALUATION .............................................................................. 84 APPENDIX D : POINTS OF INTEREST CONTOUR PLOTS ................................................................ 96 Page 5

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP List of Tables Page Table 4-1: Geometry Key Dimensions ................................................................................................... 11 Table 4-2: Material Designations ........................................................................................................... 13 Table 4-3: Material Property Symbols and Units ................................................................................... 14 Table 4-4: Material Properties for SA-533 Gr B Cl 1 (RVCH) ................................................................ 15 Table 4-5: Material Properties for Stainless Steel 308 (Cladding) ......................................................... 15 Table 4-6: Material Properties for SB-166 Alloy 600 (Existing CEDM Nozzle and J Groove Weld) ..................................................................................................................................... 16 Table 4-7: Material Properties for SB-166 Alloy 690 (IDTB Weld and New CEDM Nozzle) .................. 16 Table 4-8: ASME Code Allowable Stresses for Level A and Level B Conditions .................................. 17 Table 4-9: Maximum Pressure and Temperature .................................................................................. 17 Table 4-10: Transients for Fatigue Evaluation ....................................................................................... 18 Table 4-11: HUCD Pmax Transient Definition ....................................................................................... 19 Table 4-12: HUCD Pmin Transient Definition ........................................................................................ 20 Table 4-13: LSP Transient Definition ..................................................................................................... 21 Table 4-14: LT Tmax Transient Definition.............................................................................................. 22 Table 4-15: LT Tmin Transient Definition............................................................................................... 22 Table 4-16: PLUL Transient Definition ................................................................................................... 23 Table 4-17: Remaining Transient Definition........................................................................................... 23 Table 4-18: External Loads .................................................................................................................... 24 Table 5-1: Existing CEDM Nozzle Geometric Properties ....................................................................... 26 Table 5-2: Existing CEDM Nozzle Resulting Stress and Stress Intensity .............................................. 26 Table 5-3: IDTB Weld Geometric Properties ......................................................................................... 26 Table 5-4: IDTB Weld Resulting Stress and Stress Intensity ................................................................. 26 Table 5-5: Nodes for Temperature and Thermal Gradient Evaluation ................................................... 35 Table 5-6: Thermal Gradients ................................................................................................................. 35 Table 5-7: Time Points for HUCD Pmax Structural Evaluation .............................................................. 38 Table 5-8: Time Points for HUCD Pmin Structural Evaluation ............................................................... 40 Table 5-9: Time Points for LSP Structural Evaluation............................................................................ 42 Table 5-10: Time Points for LT Tmax Structural Evaluation .................................................................. 44 Table 5-11: Time Points for LT Tmin Structural Evaluation ................................................................... 45 Table 5-12: Time Points for PLUL Structural Evaluation ....................................................................... 46 Table 5-13: Time Points for REM Structural Evaluation ........................................................................ 47 Page 6

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP List of Tables (continued)

Page Table 5-14: Path Line and Node Identification for ASME Code Evaluation ........................................... 48 Table 5-15: Maximum Primary plus Secondary Stress Intensity ........................................................... 52 Table 5-16: Summary of Cumulative Fatigue Usage Factors ................................................................ 54 Table 5-17: Summary of Maximum Cumulative Fatigue Usage Factors ............................................... 54 Table 5-18: CFUF for Path WPath3b Inside Node(1) .............................................................................. 55 Table 5-19: CFUF for Path HPath2c Inside Node(1) ............................................................................... 55 Table 5-20: Adjusted CFUF for HPath2c Inside Node for [ ] ........................56 Table 6-1: Computer Files for CEDM IDTB Model and Verification....................................................... 59 Table 7-1: Summary of Results .............................................................................................................. 62 Table 7-2: Adjusted Number of Cycles for [ ]........................................................62 Table B-1: Nodal Hoop Stress and Location Computer Files ................................................................ 79 Table B-2: Path Line Location and Description for Fracture Mechanics Analysis .................................81 Table B-3: IDTB Weld Path Line Stress and Temperature Extraction Computer Files.......................... 82 Table B-4: Column Labels and Units for IDTB Weld Path Line Stress and Temperatures .................... 83 Table C-1 : ASME Code Allowable Stresses for Design Conditions (Level A and B)............................ 85 Table C-2: ASME Code Allowable Stresses for Emergency Conditions (Level C) ................................ 85 Table C-3: ASME Code Allowable Stresses for Faulted Conditions (Level D) ...................................... 85 Table C-4: CEDM Loads (Reference [4])............................................................................................... 87 Table C-5: Local Piping Loads Under Service Levels............................................................................ 87 Table C-6: Primary Stress Intensities at IDTB Weld .............................................................................. 88 Table C-7: Pure Shear Stresses at IDTB Weld...................................................................................... 89 Table C-8: Primary Stress Intensities at CEDM Nozzle......................................................................... 89 Table C-9: IDTB Weld Size Results....................................................................................................... 91 Page 7

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP List of Figures Page Figure 4-1: CEDM IDTB Weld Repair .................................................................................................... 12 Figure 5-1: CEDM IDTB Finite Element Model ...................................................................................... 27 Figure 5-2: CEDM IDTB Finite Element Model (Close-Up).................................................................... 28 Figure 5-3: Thermal Load Application and Boundary Conditions .......................................................... 30 Figure 5-4: Surfaces of Displacement Constraints ................................................................................ 31 Figure 5-5: Surfaces of Pressure Application ........................................................................................ 32 Figure 5-6: Design Condition Stress Intensity Contours and Deformed Shape Plot .............................. 34 Figure 5-7: Location Numbers for Evaluation of Thermal Gradients...................................................... 36 Figure 5-8: Location Numbers for Evaluation of Thermal Gradients (Close-Up on Weld) ..................... 37 Figure 5-9: Path Lines............................................................................................................................ 49 Figure 5-10: Additional Path Lines ......................................................................................................... 50 Figure A-1: HUCD Pmax Temperature Plot ........................................................................................... 65 Figure A-2: HUCD Pmax Thermal Gradient Plot ................................................................................... 66 Figure A-3: HUCD Pmin Temperature Plot ............................................................................................ 67 Figure A-4: HUCD Pmin Thermal Gradient Plot .................................................................................... 68 Figure A-5: LSP Temperature Plot......................................................................................................... 69 Figure A-6: LSP Thermal Gradient Plot ................................................................................................. 70 Figure A-7: LT Tmax Temperature Plot ................................................................................................. 71 Figure A-8: LT Tmax Thermal Gradient Plot .......................................................................................... 72 Figure A-9: LT Tmin Temperature Plot .................................................................................................. 73 Figure A-10: LT Tmin Thermal Gradient Plot ......................................................................................... 74 Figure A-11: PLUL Temperature Plot .................................................................................................... 75 Figure A-12: PLUL Thermal Gradient Plot ............................................................................................. 76 Figure A-13: REM Temperature Plot ..................................................................................................... 77 Figure A-14: REM Thermal Gradient Plot .............................................................................................. 78 Figure B-1: Path Line Locations for Fracture Mechanics Analysis ........................................................ 80 Figure C-1: Analysis Locations .............................................................................................................. 84 Figure C-2: Location of External Loads ................................................................................................. 86 Figure C-3: NB-4244(d)-1(c) .................................................................................................................. 90 Figure C-4: Weld Size Location ............................................................................................................. 91 Figure C-5: Reinforcement Area Calculation ......................................................................................... 93 Figure D-1: WPath1a and WPath3b, Event 1 Load 5 ............................................................................ 96 Page 8

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP List of Figures (continued)

Page Figure D-2: WPath1a and WPath3b, Event 3 Load 29 .......................................................................... 97 Figure D-3: HPath2c, Event 2 Load 39 .................................................................................................. 98 Figure D-4: HPath2c, Event 4 Load 9 .................................................................................................... 99 Page 9

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP

1.0 BACKGROUND

During the fall 2021 outage (2R28), as part of the ultrasonic examination (UT) for the in-service inspection at ANO-2, an axial indication was discovered on the downhill side of CEDM penetration number 46 on the reactor vessel closure head. Subsequently, an outside diameter (OD) surface eddy current test (ET) was performed to confirm the presence of a surface indication. An outside diameter surface dye penetrant test (PT) in the area of the UT indication confirmed a surface breaking indication. The Framatome IDTB weld repair solution was implemented per Reference [3] and calculation 32-9338944 (Reference [7]) was created to show the repair weld met the applicable ASME Code requirements for one cycle of operation. The analysis here, in conjunction with Reference [7], performs the full Section III design analysis for the life of repair.

CEDM #46 is located in the reactor vessel closure head at coordinates ( [ ] ) (Reference

[4]). The original nozzle is connected to the RV head with a partial penetration J-groove weld made on the inside of the RV head. The modification consists of the removal and replacement of the lower portion of the existing CEDM nozzle (including nozzle guide) at CEDM penetration #46. The upper portion of the nozzle will remain in place. The modification removes an existing portion of the pressure boundary partial penetration J-groove weld on the inside of the RVCH. The new pressure boundary weld is established in the RVCH penetration bore above the original weld.

2.0 ANALYTICAL METHODOLOGY

1. Build a three-dimensional finite element model (FEM) of the CEDM nozzle IDTB repair. The FEM geometry incorporates the reactor vessel closure head (RVCH) and cladding with the penetration of interest, J-groove weld, buttering, and IDTB weld. Appropriate material properties are applied.

2. Apply design condition pressure and temperature to the structural finite element model to obtain deformation and stresses in the model. The results of this are used to verify the correct structural behavior of the model and correct modeling of structural boundary and loading conditions.

3. Using thermal FEM, apply thermal loads for plant operating transients in the form of transient temperatures versus time with corresponding heat transfer coefficients. The results are used to determine the time points at which maximum temperature gradients develop at key locations in the model, which are evaluated in the structural analysis.

4. Convert to structural FEM, apply corresponding pressure and thermal loads (temperature gradients) at the time points identified in Step 3 and some additional time points for steady state, maximum pressure, etc.

5. Calculate the stress intensity due to external mechanical loads to be considered in evaluating the stress and fatigue criteria in Step 7.

6. Review overall stress field to determine locations to extract linearized stresses.

7. Based on the FEM results, perform ASME Code evaluation to demonstrate the CEDM nozzle IDTB repair meets the applicable stresses and fatigue requirements of the ASME Code,Section III.

3.0 ASSUMPTIONS 3.1 Unverified Assumptions There are no unverified assumptions in this analysis.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 3.2 Justified Assumptions

[

] an ambient temperature of 70°F.

Additionally, minor justified assumptions may be stated throughout the calculation as needed.

3.3 Modeling Simplifications Step 4A.3 of Reference [6], the CEDM nozzle is machined from an inside diameter of [ ] inches to

[ ] inches at the weld. The dimension in the FEM model is [ ] inches, which produces results with negligible differences.

4.0 DESIGN INPUTS 4.1 Code Classification Based on Section 3.0 of the Design Specification (Reference [3]) the RVCH is a Section III, Class 1 vessel (1968 Edition with Addenda through Summer 1970, Reference [11]) and the penetration modifications shall be in accordance with Class 1 vessels of Section III (1992 Edition with no Addenda, Reference [1]) and Code Case N-638-7 (Reference [12]).

4.2 Geometry The geometry of the CEDM nozzle #46 IDTB weld repair is per Reference [6] and the repair is illustrated in Figure 4-1. This figure is repeated from the Design Specification (Reference [3]) as it is noted that Step 4A.3 on sheet 2 of Reference [6] shows a slightly modified configuration due to additional repairs that were required at the time of installation. The process traveler 50-9338579 (Reference [8]) also provides additional final as-built data that may be used alongside the design drawing.

Table 4-1: Geometry Key Dimensions Page 11

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure 4-1: CEDM IDTB Weld Repair Page 12

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 4.3 Materials The materials are listed in Table 4-2.

Table 4-2: Material Designations Part Material Reference RVCH SA-533 Grade B Class 1 [3] (Section 5.1)

Cladding 308 Stainless Steel [3] (Section 5.1)

Existing CEDM Nozzle SB-166(1) [3] (Section 5.1)

CEDM Nozzle Guide A-296-68 Type CY-40 [3] (Section 5.1)

(4)

J Groove Weld ENiCRFe-3 (Inconel 182) [3] (Section 5.1)

IDTB Weld ERNiCrFe-7A

[3] (Section 5.2)

(CEDM to RVCH) Alloy 52M (UNS N06054)(2)

Replacement SB-166 or SB-167 CEDM Nozzle [3] (Section 5.2)

Alloy 690 (UNS N06690)(3)

CEDM Nozzle Guide SA-479 Type 304L(5) [3] (Section 5.2)

Note(s):

(1) Alloy 600 (N06600) based on the material test reports provided on sheets 6-19 of Reference [5], which show 72Ni-15Cr-8Fe content consistent with the requirements in the ASME Code Section II (Reference 9).

(2) Section 5.2.3 of Reference [3] specifies that the weld material be in accordance with 1992 NB-2000 (Reference [1]) and 2007 Section II, Part C (Reference [9]); this is for filler metal. Based on the nominal composition of this specification (28-31.5 Cr, 7-11 Fe, and balance Ni), SB-166 Alloy 690 is justified as representative of the ERNiCrFe-7A material.

(3) Section 5.2.1 of Reference 3 specifies that the replacement nozzle be in accordance with 1992 NB-2000 (Reference [1]) and Code Case N-698 (Reference [10]).

(4) Reference [9] gives the required filler metal composition as, minimum 59.0 Ni, 13-17 Cr, and 10 Fe.

Paragraph A7.4.3 of Reference [9] says the nominal composition is 65 Ni, 15 Cr, 8Fe and the typical specs are ASTM B 163, B 166, B 167, and B168, all of which have UNS Number N06600. Similar information is given in Table 3 of 1992 Edition of Section II Part C (Reference [2]), which correlates the AWS electrode classification of ENiCrFe-3 with ASTM specification B-166 / B-168 and with UNS N06600 (Alloy 600). Therefore, representative properties from SB-166 Alloy 600 are justified and used in this analysis for the original J groove weld.

(5) Nozzle Guide is not modeled, therefore material properties are not listed.

4.3.1 Material Properties Material property symbols and units are listed in Table 4-3. Material properties for the material designated in Table 4-2 are listed in Table 4-4 through Table 4-7. Metal density and specific heat values are only given in the ASME Code as a single nominal value at room temperature (temperature dependent data is not provided).

Therefore, density and specific heat are calculated with the equations shown below.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP The 1968 Section III Code edition (Reference [11]) does not provide data for Poissons Ratio, density, Thermal Conductivity, or temperature dependent tensile strength; therefore, in some cases these physical material properties for the existing materials are instead taken from the later 1992 and 2007 Code editions (Reference [2]

and [9]). The ASME Code allowable stresses are listed in Table 4-8 with the remaining values listed in Appendix C.

Density Calculation (for all temperatures greater than 70°F):

(T) = (70°F)/(1 + (T)*(T - 70°F))3

Where, (T) = Density at temperature T (70°F) = Density at room temperature (T) = Coefficient of thermal expansion at temperature T T - 70°F = change in temperature from the reference to room temperature Specific Heat Calculation:

thermal conductivity and thermal diffusivity from Table TCD (Reference [2]) along with the constant density reported in this table. This simplification using a constant density is acceptable and has a negligible effect on the results.

C = k/(TD*)

Note: density is converted to units of lbm/ft3 and thermal conductivity is converted to units of BTU/hr-ft-F for use in this equation. Thermal diffusivity (TD) has units of ft2/hr and is taken from the same source indicated in the tables below for thermal conductivity (k).

Table 4-3: Material Property Symbols and Units Symbol Parameter Unit T Temperature °F E Youngs Modulus 103 ksi Poissons Ratio Unitless Density lbm/in3 Mean Coefficient of Thermal Expansion *10-6 in/in/°F k Thermal Conductivity BTU/hr-in-°F C Specific Heat BTU/lb-°F Sm Design Stress Intensity ksi Sy Yield Stress ksi Su Ultimate Stress ksi Page 14

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 4-4: Material Properties for SA-533 Gr B Cl 1 (RVCH)

T E k C Sm Sy Su 70 29.9 0.30 0.280 6.07 1.858 0.107 26.7 50.00 80.0 200 29.5 0.30 0.279 6.38 1.950 0.115 26.7 47.15 80.0 300 29.0 0.30 0.279 6.60 1.983 0.121 26.7 45.25 80.0 400 28.6 0.30 0.278 6.82 1.983 0.127 26.7 44.50 80.0 500 28.0 0.30 0.277 7.02 1.958 0.134 26.7 43.20 80.0 600 27.4 0.30 0.277 7.23 1.917 0.141 26.7 42.00 80.0 700 26.6 0.30 0.276 7.44 1.858 0.147 26.7 41.40 80.0

[11] [9](3) [11] [11] [11]

[9](3) [2]

Table [2]

Reference Table Table Table Table Calculated Table Table PRD / Table U(2)

N-427 PRD N-426 TCD(1) N-421 N-424 Calculated Note(s):

(1) Material (Mn-1/2Mo-1/2Ni).

(2) 80 ksi is consistent with the Spec Min Tensile given in Table N-421 of Reference [11] for this material.

(3) Table PRD is in the 2008 Addenda.

Table 4-5: Material Properties for Stainless Steel 308 (Cladding)

T E k C Sm Sy Su 70 27.4 0.31 0.290 9.11 0.717 0.114 200 27.1 0.31 0.289 9.34 0.775 0.119 300 26.8 0.31 0.288 9.47 0.817 0.123 400 26.4 0.31 0.287 9.59 0.867 0.127 500 26.0 0.31 0.286 9.70 0.908 0.130 Not used in analysis 600 25.4 0.31 0.286 9.82 0.942 0.132 700 24.9 0.31 0.285 9.93 0.983 0.134

[11] [9](2) [11]

[9](2) [2]

Reference Table Table Table Calculated Table Table PRD /

N-427 PRD N-426 TCD(1)

Calculated Note(s):

(1) Material (18Cr-8Ni).

(2) Table PRD is in the 2008 Addenda.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 4-6: Material Properties for SB-166 Alloy 600 (Existing CEDM Nozzle and J Groove Weld)

T E k C Sm Sy Su 70 31.7 0.31 0.300 7.13 0.717 0.108 23.3 35.0 80.0 200 30.9 0.31 0.299 7.40 0.758 0.113 23.3 32.7 80.0 300 30.5 0.31 0.298 7.56 0.800 0.116 23.3 31.0 80.0 400 30.0 0.31 0.298 7.70 0.842 0.119 23.3 29.8 80.0 500 29.6 0.31 0.297 7.80 0.883 0.121 23.3 28.8 80.0 600 29.2 0.31 0.296 7.90 0.925 0.125 23.3 27.9 80.0 700 28.6 0.31 0.296 8.00 0.967 0.127 23.3 27.0 80.0

[11] [9](2) [9](2) [11] [2] [11] [11] [2]

Reference Table Table Table PRD / Table Table Calculated Table Table Table N-427 PRD Calculated N-426 TCD N-423 N-425 U(1)

Note(s):

(1) 80 ksi is consistent with the Spec Min Tensile given in Table N-423 of Reference [11] for SB-166.

(2) Table PRD is in the 2008 Addenda.

Table 4-7: Material Properties for SB-166 Alloy 690 (IDTB Weld and New CEDM Nozzle)

T E k C Sm Sy Su (2) 70 30.3 0.31 0.293 7.65 0.567 0.107 23.3 35.0 85.0 200 29.5 0.31 0.292 7.85 0.633 0.112 23.3 31.6 85.0 300 29.1 0.31 0.291 7.93 0.683 0.116 23.3 29.8 84.0 400 28.8 0.31 0.291 8.02 0.733 0.119 23.3 28.7 82.0 500 28.3 0.31 0.290 8.09 0.783 0.123 23.3 27.8 80.8 600 28.1 0.31 0.289 8.16 0.833 0.124 23.3 27.6 80.2 700 27.6 0.31 0.288 8.25 0.883 0.127 23.3 27.6 79.8

[2] [9](3) [9](3) [2] [2]

[10] [10] [9]

Reference Table Table Table PRD / Table Table Calculated Table 1(1) Table 1(1) Table U(1)

TM-4 PRD Calculated TE-4 TCD Note(s):

(1) SB-166 Alloy 690 (N06690) is not listed in Table 2B, Table Y-1, or Table U of 1992 Part D (Reference

[2]).

(2) Reference [2] gives a value of 0 at 70 degrees, [

]

(3) Table PRD is in the 2008 Addenda.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 4.3.2 ASME Code Allowable Stresses The allowable stresses can be found in Appendix C.

The allowable stresses for Normal (Level A) and Upset (Level B) conditions are per NB-3222 and NB-3223, respectively (Reference [1]). Allowable stresses are calculated at the Design temperature of [ ] In the case of Level B, NB-3223(a)(1) allows for an increase of 110% of Level A stress intensity limits if the Level B pressure exceeds the design pressure. Conservatively this increased allowable stress intensity is not used.

Table 4-8: ASME Code Allowable Stresses for Level A and Level B Conditions PL + Pb + Q (ksi)

Material 3Sm SA-533 Grade B Class 1 80.1 SB-166 Alloy 600 69.9 SB-166 Alloy 690 69.9 4.4 Loads 4.4.1 Design Loads The design pressure and temperature are [ ] from Section 4.0 of Reference [3].

4.4.2 Operating Transient Loads The maximum pressure and temperature values for all loading conditions are listed in Table 4-9; Table 4-10 summarizes the transients included for evaluation with the corresponding number of cycles as given in Reference [14]. The time points, temperatures, and pressures that define the transients are presented in Table 4-11 through Table 4-17; conservatively the pressures given in psia are applied as psig. For transient with a hot and cold leg temperature profile, T_hot is the applicable temperature curve Reference [15].

Table 4-9: Maximum Pressure and Temperature Page 17

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 4-10: Transients for Fatigue Evaluation Page 18

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 4-11: HUCD Pmax Transient Definition Page 19

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 4-12: HUCD Pmin Transient Definition Page 20

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 4-13: LSP Transient Definition Page 21

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 4-14: LT Tmax Transient Definition Table 4-15: LT Tmin Transient Definition Page 22

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 4-16: PLUL Transient Definition Table 4-17: Remaining Transient Definition Page 23

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 4.4.3 External Loads The external loads required for this analysis are from Reference [4] and presented in the following table.

Table 4-18: External Loads Page 24

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 5.0 CALCULATIONS 5.1 External Loads The stress contribution due to the external loads from Section 4.4.3 is manually calculated for inclusion in the primary plus secondary stresses. Section 6.1.2 of Reference [7] calculates a moment arm of [ ]

between the location of the external loads and the IDTB weld. Conservatively, this same moment arm is used here for the CEDM nozzle section just above the IDTB weld. All detailed calculations are included in Excel spreadsheet Ext_Loads_Mod.xlsx, this file is listed in Section 6.0.

Stresses are calculated at both the inside radius and outside radius of the cross-section under consideration. There is no stress contribution from the external loads acting on the replacement CEDM nozzle below the IDTB weld due to the fixed connection between the IDTB weld and the reactor vessel head. [

]

The CEDM housing nozzles function as mechanical mounts for the CEDM. The CEDM are relatively tall, slender structures that may be subjected to seismic or other motions resulting in bending loads on the CEDM nozzle-to-head connection weld. [

]

( )

Axial Stress: = +

Shear Stress: =

Axial Shear Stress = =

Stress Intensity: = +4 Stress intensity is based on the difference between maximum and minimum principal stresses (1 and 2), and simplifies to the equation shown here.

where,

= ,

,

= , = 2 Page 25

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP

,

4 Table 5-1: Existing CEDM Nozzle Geometric Properties Table 5-2: Existing CEDM Nozzle Resulting Stress and Stress Intensity Table 5-3: IDTB Weld Geometric Properties Table 5-4: IDTB Weld Resulting Stress and Stress Intensity 5.2 Finite Element Model The finite element model (FEM) is developed using ANSYS 19.2 (Reference [13]) and the model is shown in Figure 5-1 and Figure 5-2. The solid model and mesh are developed in ANSYS Workbench and exported to classic ANSYS for definition of material properties, boundary condition and load application, solution and post-processing. Also, per Step 4 of Reference [6], the CEDM nozzle is machined from an inside diameter of

[ ] inches to [ ] inches at the weld. The dimension in the FEM model is [ ] inches, which produces results with negligible differences.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP The FEM is shown in Figure 5-1 and Figure 5-2. The thermal element types are SOLID90 (3-D 20-node brick thermal solid) and SOLID87 (3-D 10-node tetrahedral thermal solid). The structural element types are SOLID186 (3-D 20-node structural solid) and SOLID187 (3-D 10-node Tetrahedral Structural Solid) for the structural analysis.

Figure 5-1: CEDM IDTB Finite Element Model Page 27

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure 5-2: CEDM IDTB Finite Element Model (Close-Up) 5.2.1 Boundary Conditions One-half (180o) of the nozzle is modeled due to symmetry over the vertical-radial plane. The vertical plane containing the vertical central axis of the RVCH and vertical central axis of the CEDM nozzle forms the plane of symmetry for the modeled portion of the nozzle. The thermal and structural boundary conditions are reflective on this plane.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 5.2.1.1 Thermal Analysis Page 29

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure 5-3: Thermal Load Application and Boundary Conditions 5.2.1.2 Structural Analysis The symmetric boundary conditions are applied to the planes of symmetry (n_symm_front in Figure 5-4). The RVCH edge surfaces are allowed to displace in the direction that is radial to the RVCH center of curvature (n_symm_back, n_symm_right and n_symm_left in Figure 5-4). All surfaces that are in contact with pressurized reactor coolant fluid are subjected to pressure loads (n_surf_wetted in Figure 5-5). The upper end of the nozzle has a pressure (PBO) applied to represent the hydrostatic end load from the piping closure (n_noz_orig_end_cap in Figure 5-5) calculate as:

PBO = -p(NozID/2)2/((NozOD/2)2 -(NozID/2)2)

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Where:

p = Transient pressure NozID = [ ] in (Reference [6])

NozOD = [ ] in (Reference [6])

Figure 5-4: Surfaces of Displacement Constraints Page 31

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure 5-5: Surfaces of Pressure Application 5.3 Design Condition The ANSYS output file ANO_Design_Cond.out listed in Table 6-1 contains results of the Design Condition analysis using the loads designated in Section 4.4.1 and boundary conditions discussed in Section 5.2.1.2.

Figure 5-6 shows the stress intensity contours along with the deformed shape of the model (note that the deformation is not to scale). The results shown in Figure 5-6 verify the correct behavior of the FEM and stress attenuation at regions distant from the nozzle location. The calculated stress intensity shown below falls within the stress range of the RVCH and existing nozzle far from the weld. The stress formulas are from Reference [18]

for a thick-walled vessel, where the max principal stresses are in order.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP For RVCH:

, = =

For existing nozzle:

Where, q = Pressure = [ ]

b = Inside radius = [ ]

a = Outside radius = [ ]

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure 5-6: Design Condition Stress Intensity Contours and Deformed Shape Plot 5.4 Thermal Analysis The thermal analysis files are listed in Table 6-1and are designated as ANO_**_TH.out, with ** equal to transient abbreviation given in Table 4-10 (Reference [14]). The thermal analyses use the temperature data given in Table 4-11 through Table 4-17 (files designated as ANO_**_TR.inp are read into the files ANO_**_TH.out) and boundary conditions listed in Section 5.2.1.1.

Temperature gradients between key locations are used to determine time points for structural evaluation. The nodes selected are listed in Table 5-5 and the thermal gradient locations are listed in Table 5-6. The locations are illustrated in Figure 5-7 and Figure 5-8. The thermal gradients files are listed Table 6-1 and are designated as ANO_**_DT.out, with ** equal to transient abbreviation given in Table 4-10. The thermal gradient results are obtained from the output files, however Appendix A contains the temperature and thermal gradient plots for all transients analyzed.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-5: Nodes for Temperature and Thermal Gradient Evaluation Table 5-6: Thermal Gradients Page 35

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure 5-7: Location Numbers for Evaluation of Thermal Gradients Page 36

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure 5-8: Location Numbers for Evaluation of Thermal Gradients (Close-Up on Weld) 5.5 Structural Analysis From the thermal analysis results, time points are selected for structural evaluation based on peak thermal gradients. Time points are also selected for maximum pressure and temperatures. The time points selected for the analyzed transients are listed in Table 5-7 through Table 5-13.

The structural analysis files are listed Table 6-1 and are designated as ANO_**_ST.out, with ** equal to transient abbreviation given in Table 4-10 (Reference [14]). The structural analyses use the pressure data given in Table 4-11 through Table 4-17 files designated as ANO_**_TR.inp are read into the files ANO_**_ST.out).

Nodal temperature data for the time points are read into the structural file directly from the thermal analysis result files (ANO_**_TH.rth). Boundary conditions applied are listed in Section 5.2.1.2.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-7: Time Points for HUCD Pmax Structural Evaluation Page 38

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Page 39

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-8: Time Points for HUCD Pmin Structural Evaluation Page 40

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Page 41

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-9: Time Points for LSP Structural Evaluation Page 42

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Page 43

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-10: Time Points for LT Tmax Structural Evaluation Page 44

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-11: Time Points for LT Tmin Structural Evaluation Page 45

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-12: Time Points for PLUL Structural Evaluation Page 46

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-13: Time Points for REM Structural Evaluation 5.6 ASME Code Evaluation The ASME Code stress analysis involves two basic sets of criteria:

1. Assure that failure does not occur due to application of the design loads.

2. Assure that failure does not occur due to repetitive loading.

In general, the Primary Stress Intensity criteria of the ASME Code (Reference [1]) assure that the design is adequate for application of design loads. The ASME Code criteria for cumulative fatigue usage factor assure that the design is adequate for repetitive loading.

The ANSYS post-processor is used to tabulate the stresses along the predetermined paths through the IDTB weld, nozzle and RVCH thickness and classify them in accordance with ASME Code Criteria. These path lines are shown in Figure 5-9 and Figure 5-10 and described in Table 5-14.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-14: Path Line and Node Identification for ASME Code Evaluation Page 48

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure 5-9: Path Lines Page 49

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure 5-10: Additional Path Lines Page 50

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 5.6.1 Primary Stress Criteria Primary stress evaluation was done in Document No. 32-9338944-001 (Reference [7]). A duplication of the calculations from Section 6.0 and Appendix A from Reference [7] can be found in Appendix C.

5.6.2 Primary Plus Secondary Stress and Fatigue Usage Criteria 5.6.2.1 Primary plus Secondary Stress Intensity Range (NB-3222.2)

The ANSYS fatigue module is used to calculate the maximum stress intensity range at each node of the selected path lines for all transients. The module complies with ASME Code Section III in calculating a stress intensity range. The Zero Stress State (ZSS) is also included in these runs. The ANSYS output files (listed in Table 6-1) containing the results of the stress range calculation for membrane plus bending stresses are:

ANO_Fatigue_Carbon_M+B_Pmin.out (for HPath1a, HPath1c, HPath1b, HPath2a, HPath2c, HPath2b)

ANO_Fatigue_Alloy690_M+B_Pmin.out (for WPath1a-4a, WPath1c-4c, WPath1b-4b)

The maximum primary plus secondary stress intensity (SI) ranges occurs for combination of the transients HUCD_Pmin and LT (Tmax is used in LT). All paths with this combination are tabulated in Table 5-15. The allowable primary plus secondary stress is 80.1 ksi for SA-533 Grade B, Class 1 and 69.9 ksi for Alloy 600 and Alloy 690 (Table 4-8). Table 5-15 includes the alternating stress intensities generated from the OBE and IMP (Deadweight is also conservatively included) shear stress loads, which is an additional load of [ ]

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-15: Maximum Primary plus Secondary Stress Intensity Allowable Path Name Inside Node Outside Node ksi WPath1a 19999 37662 WPath1c 26852 35326 WPath1b 21092 35364 WPath2a 19999 4260 WPath2c 26852 23053 69.9 WPath2b 21092 4241 WPath3a 4260 31606 WPath3c 23053 30743 WPath3b 4241 30703 HPath1a 23053 4260 HPath1c 24057 23053 HPath1b 20700 4241 80.1 HPath2a 19999 8024 HPath2c 26852 26818 HPath2b 21092 18567 WPath4a 39991 37462 WPath4c 39352 35116 69.9 WPath4b 39390 35154 Since the maximum primary plus secondary stress intensity range is less than the allowable value, the requirement is met.

5.6.2.2 Fatigue Usage Criteria (NB-3222.4)

The analysis of stresses for transient conditions is required to satisfy the requirements for repetitive loading. The following discussion describes the fatigue analysis process employed herein for the design.

As described in Section 5.5, the runs for each transient instant time are contained in the ANSYS solution outputs with file names ending with st. See Section 6.0 for a complete list of output files for runs with pressure and temperature. Overall stress levels are reviewed and assessed to determine which model locations require detailed stress/fatigue analysis. The areas of interest include stress concentrations, dissimilar metal junctions (triple point),

repair weld, existing nozzle, and RVCH. The objective is to assure that the most severely stressed locations are evaluated, and the specified region is quantitatively qualified. Once the specific locations for detailed stress evaluation are established, the ANSYS paths are defined. Post-processing runs for these paths are made to convert the component stresses along these paths into Stress Intensity (SI) categories that correlate to the criteria of the ASME Code (i.e., membrane, membrane+bending, total).

For consideration of fatigue usage, the peak stress intensity ranges are calculated. These values must include the total localized stresses. The geometry of the CEDM nozzle, IDTB weld and RVCH results in a crevice-like configuration between the nozzle OD and the penetration bore diameter. Therefore, there are stress Page 52

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP concentrations at these locations that must be incorporated into the finite element stresses. To account for these stress concentration locations, a fatigue strength reduction factor (FSRF) is applied to the membrane plus bending (M+B) stress intensity ranges for locations experiencing discontinuity.

In other words, areas of singularities (i.e., crevice/notch locations) may include fictious stresses. To remove these stresses, the ASME code implements a linearized stress profile. An example of the stress profile can be found in Fig. NB-3653.2(b)-1 and denoted in paragraphs NB-3653.2(b)(1) through NB-3653.2(b)(3), Reference [1]. Since the linearized stress profile excludes peak stresses, an FSRF must be included to compensate for the reduction in stress.

In the following cumulative fatigue usage factor (CFUF) calculations, the linearized membrane plus bending stress intensity range at crevice/notch locations are multiplied by a FSRF of four (4) (Reference [1],

NB-3352.4 (d)(5)) to represent the peak stress intensity range. An FSRF of [ ]

applied to all other nodes along the inside surface of the nozzle and weld (Reference [1], NB-3352.2). Nodes along the ID and OD of the RVCH of path lines HPath2a, HPath2b and HPath2c are far from any discontinuities have a FSRF of 1. The maximum membrane plus bending stress intensity ranges are obtained from the post-processing listed below as mentioned in Section 5.6.2.1. The stress intensity ranges and the CFUF are documented in the following ANSYS output files (Table 6-1):

ANO_Fatigue_Carbon_M+B_Pmin.out (for HPath1a, HPath1c, HPath1b, HPath2a, HPath2c, HPath2b)

ANO_Fatigue_Alloy690_M+B_Pmin.out (for WPath1a-4a, WPath1c-4c, WPath1b-4b)

The highest CFUF occurs with the combination of transients HUCD_Pmin and LT (Tmax is used in LT).

Table 5-16 contains the summary of the CFUFs for all path nodes with this combination. Table 5-17 list the maximum CFUF and with the addition of OBE and IMP (Deadweight is conservatively included) stress intensity shear stress loads [ ] see Section 4.4.3 and Section 5.1. Table 5-18 and Table 5-19 show detailed calculations of the CFUF for paths WPath3b (inside node) and HPath2c (inside node). For the location (HPath2c, inside node) with the largest CFUF, the design cycles are reduced to obtain a CFUF of 1.000 to determine the allowable number of operating cycles/years of operation. The adjusted CFUF for HPath2c, inside node is calculated in Table 5-20 for [ ] of operation (Reference [3]).

Its important to add that the fatigue computer runs are used to determine the stress intensity ranges and number of cycles used for each stress range. This raw data is further processed in accordance with the ASME Code as documented in Table 5-17 through Table 5-20. The calculations can also be found in ANO-2_IDTB_Fat_Calc_3_Reduced_NOC.xls.

Table 5-16 contains the raw data from the computer output files for CFUF and does not include the additional stress intensities from external loads. Also note that events 1, 2 and 3 in Table 5-18 through Table 5-20 correspond to events 1b, 2b and 3a in Table 5-7 through Table 5-13.

Appendix D contains contour plots with time steps corresponding to paths WPath1a, WPath3b and HPath2c.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-16: Summary of Cumulative Fatigue Usage Factors Table 5-17: Summary of Maximum Cumulative Fatigue Usage Factors Page 54

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 5-18: CFUF for Path WPath3b Inside Node(1)

Table 5-19: CFUF for Path HPath2c Inside Node(1)

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP

where, Event #, Load, SI Range and Used Cycles are ANSYS outputs.

SI_Alt = 1/2

SI Range

FSRF Allowed Cycles are determined from the fatigue curve after SI_Alt has been corrected with the elastic modulus ratio.

Partial Usage = Used Cycles / Allowed Cycles Table 5-20: Adjusted CFUF for HPath2c Inside Node for [ ]

5.6.3 Corrosion Evaluation The design configuration of the nozzle repair results in a small area of the RVCH base material being exposed to continuous contact with reactor coolant water. The chemistry of the reactor coolant combined with properties of the RVCH wall material result in corrosion of the wetted surface.

The corrosion rate is determined to be [ ] per year (Reference [7]). At this rate, the total surface corrosion volume loss does not have a significant impact on the analysis unless noted in the calculation.

Conservatively, the loss of material is assumed to be evenly through the head bore base material, which increases the bore diameter. The increase in diameter has a negligible effect on the stress levels and stress distributions in the wall. Thus, the larger bore diameter does not impact the stress and fatigue usage for the assembly and is acceptable.

In conclusion, the corrosion of the exposed base material has negligible impact on the response of the RVCH nozzle repair and is therefore acceptable for the life of repair.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 5.7 Justification of Dissimilar Materials of the Replacement Guide and Replacement Nozzle Page 57

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 6.0 COMPUTER USAGE 6.1 Software The following EASI List computer program ANSYS Release 19.2 is used in this calculation (Reference [13]).

Verification tests of similar applications are listed as follows:

x Computer program tested: ANSYS Release 19.2 verification tests VM161 for SOLID90, VM96 for SOLID87, VM144 for SOLID186 and VM244 for SOLID187. Error notices for ANSYS Release 19.2 are reviewed and none apply for this analysis.

x Computer hardware used: ThinkPad (Service Tag #: Tstraka6, PF1LTM57) with Intel Core i7-8850H CPU @ 2.50GHz, 16.0 GB of RAM and Operating System is Microsoft Windows 10 Enterprise Version 21H2 x Name of person running tests: Tomas Straka x Date of tests: September 08, 2022 and October 24, 2022 x Acceptability: Results shown in files VM161.out, VM96.out, VM144.out and VM244.out show that the test runs are acceptable.

6.2 Computer Files Table 6-1 list the computer files used in this analysis. These files are located in the Framatome Inc. ColdStor system in folders\cold\General-Access\32\32-9000000\32-9348826-000\official\Model and \cold\General-Access\32\32-9000000\32-9348826-000\official\VER. Note that Pmin and Tmin are denoted in the computer file names for HUCD and LT transients, while Pmax and Tmax are omitted in the names. Computer files for fracture runs can be found in Appendix B.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table 6-1: Computer Files for CEDM IDTB Model and Verification File name Date/Time Modified CRC ANO2_Model_WB.dat Aug 20 2022 14:13:21 47353 ANO_Fatigue_Alloy690_M+B.inp Sep 12 2022 15:52:04 52447 ANO_Fatigue_Alloy690_M+B_Pmin+Tmin.inp Sep 12 2022 15:55:31 396 ANO_Fatigue_Alloy690_M+B_Pmin.inp Sep 12 2022 15:54:03 19788 ANO_Fatigue_Alloy690_M+B_Tmin.inp Sep 12 2022 15:57:06 16812 ANO_Fatigue_Carbon_M+B.inp Sep 12 2022 16:01:24 46513 ANO_Fatigue_Carbon_M+B_Pmin+Tmin.inp Sep 12 2022 16:18:18 15980 ANO_Fatigue_Carbon_M+B_Pmin.inp Sep 12 2022 16:16:59 40830 ANO_Fatigue_Carbon_M+B_Tmin.inp Sep 12 2022 16:22:05 5067 ANO_HUCD_DT.inp Sep 08 2022 17:00:37 32176 ANO_HUCD_Pmin_DT.inp Sep 08 2022 16:56:29 11106 ANO_HUCD_Pmin_ST.inp Sep 09 2022 19:29:56 22979 ANO_HUCD_Pmin_TH.inp Sep 08 2022 16:58:34 2511 ANO_HUCD_Pmin_TR.inp Aug 08 2022 10:04:36 50376 ANO_HUCD_ST.inp Sep 09 2022 19:25:56 39724 ANO_HUCD_TH.inp Sep 08 2022 17:03:14 49217 ANO_HUCD_TR.inp Sep 08 2022 16:37:18 46525 ANO_LSP_DT.inp Sep 08 2022 19:34:59 7930 ANO_LSP_ST.inp Sep 09 2022 19:21:04 18572 ANO_LSP_TH.inp Sep 08 2022 19:37:03 20813 ANO_LSP_TR.inp Aug 20 2022 19:18:51 49431 ANO_LT_DT.inp Sep 08 2022 19:42:26 27809 ANO_LT_ST.inp Sep 09 2022 19:17:03 6631 ANO_LT_TH.inp Sep 09 2022 10:06:21 14668 ANO_LT_TR.inp Aug 09 2022 15:35:38 17765 ANO_LT_Tmin_DT.inp Sep 08 2022 19:39:06 7070 ANO_LT_Tmin_ST.inp Sep 09 2022 18:56:14 41390 ANO_LT_Tmin_TH.inp Sep 08 2022 19:41:02 8122 ANO_LT_Tmin_TR.inp Aug 09 2022 15:36:56 64604 ANO_PLUL_DT.inp Sep 08 2022 19:45:03 40376 ANO_PLUL_ST.inp Sep 09 2022 19:08:40 34178 ANO_PLUL_TH.inp Sep 08 2022 19:47:27 16371 ANO_PLUL_TR.inp Sep 09 2022 14:33:27 27715 ANO_REM_DT.inp Sep 09 2022 11:18:53 31985 ANO_REM_ST.inp Sep 09 2022 19:13:21 29514 Page 59

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP ANO_REM_TH.inp Sep 09 2022 10:04:55 54854 ANO_REM_TR.inp Sep 08 2022 18:47:46 31347 Ext_Loads_Mod.xlsx Oct 05 2022 14:16:28 46778 Model.inp Sep 08 2022 13:28:41 686 Paths.mac Sep 10 2022 21:07:43 41930 Paths_Fat.mac Sep 11 2022 22:15:24 38229 ano_fatigue_alloy690_m+b.out Sep 12 2022 16:28:11 37202 ano_fatigue_alloy690_m+b_pmin+tmin.out Sep 12 2022 16:38:01 63800 ano_fatigue_alloy690_m+b_pmin.out Sep 12 2022 16:33:45 17322 ano_fatigue_alloy690_m+b_tmin.out Sep 12 2022 16:41:59 41066 ano_fatigue_carbon_m+b.out Sep 12 2022 16:50:12 58218 ano_fatigue_carbon_m+b_pmin+tmin.out Sep 12 2022 17:05:22 62342 ano_fatigue_carbon_m+b_pmin.out Sep 12 2022 16:58:51 10198 ano_fatigue_carbon_m+b_tmin.out Sep 12 2022 17:11:27 29275 ano_hucd_dt.out Sep 08 2022 22:49:36 43604 ano_hucd_pmin_dt.out Sep 08 2022 21:27:47 52832 ano_hucd_pmin_st.out Sep 09 2022 20:00:38 31199 ano_hucd_pmin_th.out Sep 08 2022 21:27:40 28736 ano_hucd_st.out Sep 09 2022 20:22:41 47129 ano_hucd_th.out Sep 08 2022 22:49:29 33769 ano_lsp_dt.out Sep 09 2022 01:40:31 284 ano_lsp_st.out Sep 09 2022 21:13:30 17701 ano_lsp_th.out Sep 09 2022 01:40:24 41912 ano_lt_dt.out Sep 09 2022 10:52:59 2955 ano_lt_st.out Sep 09 2022 20:49:28 27304 ano_lt_th.out Sep 09 2022 10:52:54 2504 ano_lt_tmin_dt.out Sep 09 2022 00:08:45 47895 ano_lt_tmin_st.out Sep 09 2022 20:50:19 48588 ano_lt_tmin_th.out Sep 09 2022 00:08:40 14810 ano_plul_dt.out Sep 09 2022 15:30:16 19110 ano_plul_st.out Sep 09 2022 20:34:58 15728 ano_plul_th.out Sep 09 2022 15:30:11 31589 ano_rem_dt.out Sep 09 2022 11:22:19 56440 ano_rem_st.out Sep 09 2022 20:55:42 12725 ano_rem_th.out Sep 09 2022 11:13:28 18245 model.out Sep 08 2022 20:04:49 61522 timepoint_selection.mac Aug 25 2022 11:00:45 21180 Page 60

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP ANO-2_IDTB_Fat_Calc_3_Reduced_NOC.xls Oct 05 2022 15:05:35 12158 VM144.out Sep 08 2022 20:01:50 19908 VM161.out Sep 08 2022 20:01:54 46023 VM244.out Sep 08 2022 20:01:59 62994 VM96.out Sep 08 2022 20:01:47 55628 VM144.out Oct 24 2022 14:33:14 39449 VM161.out Oct 24 2022 14:33:17 59582 VM244.out Oct 24 2022 14:33:23 28591 VM96.out Oct 24 2022 14:33:10 27046 Page 61

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP 7.0 RESULTS & CONCLUSIONS The primary stresses are qualified in Reference [7]. Table 7-1 contains the summary of results from the model described in the main body of this document. Note that the Closure head base material is bounding for fatigue.

Table 7-1: Summary of Results The number of cycles/operating years is adjusted by ratioing the actual and allowable CFUF and with the used cycles to obtain a CFUF of 1.000 in the RVCH/Weld area. Therefore, to obtain a [

] is considered acceptable for the model.

Table 7-2 shows the number of operating cycles that corresponds [

] after the repair has been implemented. The calculated life of the repair of [

]

Table 7-2: Adjusted Number of Cycles for [ ]

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP

8.0 REFERENCES

1. ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Facility Components, Division 1, 1992 Edition with no Addenda.

2. ASME Boiler and Pressure Vessel Code,Section II, Materials, 1992 Edition with no Addenda. (Part C

- Specifications for Welding Rods, Electrodes, and Filler Metals, and Part D - Properties)

3. Framatome Design Specification 08-9338577-003, [ ]

4. Framatome Document 38-2201963-001, [

]

5. Framatome Document 38-9338710-000, [ ]

6. Framatome Drawing 02-9338578-E-002, [ ]

7. Framatome Calculation 32-9338944-001, [

]

8. Framatome Document 50-9338579-000, [

]

9. ASME Boiler and Pressure Vessel Code,Section II, Materials, 2007 Edition with no Addenda (Part C -

Specifications for Welding Rods, Electrodes, and Filler Metals, and Part D - Properties (Customary)).

10. Code Case N-698, Design Stress Intensities and Yield Strength Values for UNS N06690 with a Minimum Specified Yield Strength of 35 ksi (240MPa), Class 1 ComponentsSection III, Division 1, 2003. This Code Case is acceptable per Regulatory Guide 1.84, Revision 38.

11. ASME Boiler and Pressure Vessel Code,Section III, Rules for Construction of Nuclear Facility Components, Division 1, 1968 Edition with Addenda through Summer 1970.

12. Code Case N-638-7, Similar and Dissimilar Metal Welding Using Ambient Temperature Machine GTAW Temper Bead Technique,Section XI, Division 1, 2013. This Code Case is conditionally acceptable per Regulatory Guide 1.147, Revision 19.

13. ANSYS Mechanical Enterprise, ANSYS Finite Element Computer Code, Version 19.2, ANSYS Inc.,

Canonsburg, PA.

14. Framatome Document 38-2201967-000, [

]

15. Framatome Document 38-9353133-000, [

]

16. Framatome Document 51-9338948-001, [

]

17. ASME Boiler and Pressure Vessel Code,Section II, Material Specifications Part B - Nonferrous, 1968 Edition with Addenda through Summer 1970.

18. Roarks Formulas for Stress and Strain, 7th Edition, Warren C. Young and Richard G. Budynas, McGraw-Hill, 2002.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP APPENDIX A: TRANSIENT TEMPERATURE AND THERMAL GRADIENT PLOTS The temperature and thermal gradient plots for the model documented in the main body of this calculation are listed in Figure A-1 through Figure A-14.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-1: HUCD Pmax Temperature Plot Page 65

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-2: HUCD Pmax Thermal Gradient Plot Page 66

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-3: HUCD Pmin Temperature Plot Page 67

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-4: HUCD Pmin Thermal Gradient Plot Page 68

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-5: LSP Temperature Plot Page 69

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-6: LSP Thermal Gradient Plot Page 70

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-7: LT Tmax Temperature Plot Page 71

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-8: LT Tmax Thermal Gradient Plot Page 72

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-9: LT Tmin Temperature Plot Page 73

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-10: LT Tmin Thermal Gradient Plot Page 74

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-11: PLUL Temperature Plot Page 75

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-12: PLUL Thermal Gradient Plot Page 76

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-13: REM Temperature Plot Page 77

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure A-14: REM Thermal Gradient Plot Page 78

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP APPENDIX B: STRESSES FOR FRACTURE MECHANICS ANALYSIS Post-processing for all transients is done to extract stresses and nodal coordinates for fracture mechanics analysis for the original model described in the main body of this document.

B.1 Nodal Hoop Stresses and Location Extraction Nodal hoop stresses and location coordinates are extracted for all nodes on the global X-Y plane (i.e. Z equals zero). In the global coordinate system, hoop stresses are in the Z direction (Sz). The computer output files are listed in Table B-1 and located in the Framatome Inc. ColdStor system in folder \cold\General-Access\32\32-9000000\32-9348826-000\official\Fracture\Nodal_Hoop. Transient abbreviations are given in Table 4-10.

Table B-1: Nodal Hoop Stress and Location Computer Files Name Date/Time Modified CRC Description Get_Transient_Stress.inp Sep 15 2022 17:29:39 51360 Post-processing of stresses and other Get_Transient_Stress.out Sep 16 2022 07:02:22 14091 parameters for all transients.

ANO_Design_Cond.sav Sep 15 2022 17:33:29 46040 ANO_HUCD.sav Sep 15 2022 20:36:39 4036 ANO_HUCD_Pmin.sav Sep 16 2022 00:04:42 3194 ANO_LSP.sav Sep 16 2022 02:32:45 51594 Nodal hoop stress and nodal temperatures for ANO _LT.sav Sep 16 2022 04:32:11 59343 all selected nodes as a function of time.

ANO _LT_Tmin.sav Sep 16 2022 04:38:28 76 ANO _PLUL.sav Sep 16 2022 06:18:25 48313 ANO _REM.sav Sep 16 2022 07:02:21 51463 UCTrxyz.sav Sep 15 2022 17:30:25 34994 Nodal Coordinates B.2 IDTB Weld Path Lines Stress and Temperature Extraction For stress and temperature evaluation, paths defined through the IDTB weld as illustrated in Figure B-1 and listed in Table B-2. The stresses are listed in a local cylindrical coordinate system with the X axis radial, the Y axis hoop and the Z axis axial. The radial (Sx), hoop (Sy) and axial (Sz) stresses and temperatures (Th) are listed at 12 equidistant intervals (13 locations) along the path for all transient time points. The equidistant intervals (distance along the path from the inside node) for all paths are document in Fr_PathLocs.out.

The computer output files are listed in Table B-3 and located in the Framatome ColdStor system in folder

\cold\General-Access\32\32-9000000\32-9348826-000\official\Fracture\Weld_Stresses. Transient abbreviations are given in Table 4-10. Table B-4 illustrates the data columns and units for the transient thermal and stress files.

Note that for paths 10 through 12 for the RVCH material stresses at all interval locations are not valid if the path location does not contain head material.

Page 79

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure B-1: Path Line Locations for Fracture Mechanics Analysis Page 80

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table B-2: Path Line Location and Description for Fracture Mechanics Analysis Path Number Path Name(1) Inside Node(2) Outside Node(3) Component 1 WPath1a 19999 37662 IDTB Weld 2 WPath1c 26852 35326 IDTB Weld 3 WPath1b 21092 35364 IDTB Weld 4 WPath2a(4) 19999 4260 IDTB Weld (4) 5 WPath2c 26852 23053 IDTB Weld (4) 6 WPath2b 21092 4241 IDTB Weld 7 WPath3a 4260 31606 IDTB Weld 8 WPath3c 23053 30743 IDTB Weld 9 WPath3b 4241 30703 IDTB Weld (4) 10 HPath1a 23053 4260 RVCH 11 HPath1c(4) 24057 23053 RVCH (4) 12 HPath1b 20700 4241 RVCH Note(s):

(1) Group a, b, & c are the uphill, middle, and downhill path line groups, respectively.

(2) Top node if the path line is vertical.

(3) Bottom node if the path line is vertical.

(4) Vertical path lines Page 81

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table B-3: IDTB Weld Path Line Stress and Temperature Extraction Computer Files Date/Time Name CRC Description Modified Fr_Paths.inp Sep 10 2022 21:12:54 41221 Post-processing files to obtain stresses and Fr_Paths.out Sep 10 2022 21:46:25 1389 temperature values for all transients Fr_PathLocs.out Sep 10 2022 21:46:25 37662 Equidistant intervals for all 6 paths HUCD_fr_SY.out Sep 10 2022 21:23:05 23008 HUCD_fr_SZ.out Sep 10 2022 21:23:05 47261 HUCD_fr_Sx.out Sep 10 2022 21:23:05 55068 HUCD_fr_TH.out Sep 10 2022 21:23:05 48440 HUCD_Pmin_fr_SY.out Sep 10 2022 21:30:49 11364 HUCD_Pmin _fr_SZ.out Sep 10 2022 21:30:49 48916 HUCD_Pmin _fr_Sx.out Sep 10 2022 21:30:49 21081 HUCD_Pmin Sep 10 2022 21:30:49 12162

_fr_TH.out LSP_fr_SY.out Sep 10 2022 21:36:20 56246 LSP_fr_SZ.out Sep 10 2022 21:36:20 59709 LSP_fr_Sx.out Sep 10 2022 21:36:20 30169 LSP_fr_TH.out Sep 10 2022 21:36:20 18802 LT_fr_SY.out Sep 10 2022 21:40:47 46653 LT_fr_SZ.out Sep 10 2022 21:40:47 57618 Output files containing stresses and temperature values for all transients LT_fr_Sx.out Sep 10 2022 21:40:47 19442 LT_fr_TH.out Sep 10 2022 21:40:47 32733 LT_Tmin_fr_SY.out Sep 10 2022 21:41:01 32235 LT_Tmin_fr_SZ.out Sep 10 2022 21:41:01 43348 LT_Tmin_fr_Sx.out Sep 10 2022 21:41:01 3490 LT_Tmin_fr_TH.out Sep 10 2022 21:41:01 26069 PLUL_fr_SY.out Sep 10 2022 21:44:46 35333 PLUL_fr_SZ.out Sep 10 2022 21:44:46 48616 PLUL_fr_Sx.out Sep 10 2022 21:44:46 32052 PLUL_fr_TH.out Sep 10 2022 21:44:46 26213 REM_fr_SY.out Sep 10 2022 21:46:25 57562 REM_fr_SZ.out Sep 10 2022 21:46:25 23817 REM_fr_Sx.out Sep 10 2022 21:46:25 25196 REM_fr_TH.out Sep 10 2022 21:46:25 7519 Page 82

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table B-4: Column Labels and Units for IDTB Weld Path Line Stress and Temperatures File Type(1) Column 1 Column 2 Column 3-15

- _fr_Sx.out

- _fr_SY.out Stress (psi)

Path Numbers Time (hour)

- _fr_SZ.out

- _fr_TH.out Temperature (°F)

Note(s)

(1) With ** equal to the transient abbreviation given in Table B-3 Page 83

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP APPENDIX C: PRIMARY STRESS EVALUATION Following section is for the Primary Stress Evaluation which was prepared as a part of the OCJ task. It is from Reference [7].

All calculations were completed in excel file shallow cut_REVISED_OCJ_IDTB Weld_ANO2. This file can be found in Framatome Inc ColdStor system in folder cold/General-Access/32/32-9000000/32-9338944-001.

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

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

C.1 Primary Stress Evaluation Per Reference [3], a primary stress intensity evaluation is required using the criteria of Reference [1]. The evaluation checks stresses on the IDTB weld and the CEDM nozzle due to internal pressure and external loads.

Stresses at each service level are evaluated. Figure C-1 describes the locations analyzed. Conservatively, the nozzle analysis location uses the same moment arm as the weld analysis.

Figure C-1: Analysis Locations Page 84

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Based on the slow corrosion rate [ ] computed in Reference [16], it is concluded that corrosion has an insignificant impact on the CEDM nozzle and the weld. However, the effects of corrosion are considered in the reinforcement requirements only for the RVCH as it is made of low alloy steel. The length of time used in the calculations considering corrosion is [ ]

C.1.1 ASME Code Allowable Stresses Allowable stresses are calculated at the design temperature of [ ] using Reference [11].

Table C-1 : ASME Code Allowable Stresses for Design Conditions (Level A and B)

Membrane Membrane + Bending Pure Shear Location (ksi) (ksi) (ksi)

Sm 1.5Sm 0.6Sm IDTB Weld and CEDM 23.30 34.95 13.98 The allowable stresses for Normal (Level A) and Upset (Level B) Conditions are per NB-3222 and NB-3223 respectively, Reference [1]. Level A and B stress are bounded by the design conditions. Note that Reference [1]

states that Level B allowable stress intensity values shall be increased to 110% of the values given on Figure NB-3221-1. Conservatively, this is not considered. The allowable stresses for pure shear are per NB-3227.2.

Table C-2: ASME Code Allowable Stresses for Emergency Conditions (Level C)

Membrane Membrane + Bending Pure Shear Location (ksi) (ksi) (ksi) 1.2Sm 1.8Sm 1.2(0.6Sm)

IDTB Weld and CEDM 27.96 41.94 16.78 The allowable stresses for emergency (Level C) Conditions are per NB-3224, Reference [1].

Table C-3: ASME Code Allowable Stresses for Faulted Conditions (Level D)

Membrane Membrane + Bending Pure Shear Location (ksi) (ksi) (ksi) 2.4Sm 1.5(2.4Sm) 0.42Su (1)

IDTB Weld and CEDM 55.92 83.88 33.60 Note(s)

(1) Su value is from Table I Reference [17].

The allowable stresses for Faulted (Level D) Conditions are per NB-3225 and Appendix F, Reference [1]. Note that the primary side hydrostatic test condition is not checked since it is not expected to be performed anymore.

Page 85

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP C.1.2 Loading The external mechanical loadings are specified in Reference [4]. The internal pressure used in the analysis is

[ ] specified in Reference [3] as design pressure. Based on Reference [4], the external loads are applied at the RVCH outer surface and CEDM nozzle junction. Conservatively, the uphill side of the CEDM nozzle and RVCH outer surface location is used as the point the external loads act on. Figure C-2 shows the location the external loads act on.

Figure C-2: Location of External Loads Page 86

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP The uphill side location was calculated to be [ ] away from the weld, this is the value used as the moment arm. Applicable loads from Reference [4] are collected in Table C-4 where the direction A is the nozzle axial positive upwards, B is horizontal positive outwards, and C is determined by the right-hand rule.

Table C-4: CEDM Loads (Reference [4])

The load combinations are specified in Reference [4]. For primary stress evaluation, the load combinations are listed as follows:

Table C-5 calculates the services loads based on the loading combinations, where x, y. and z are the directions a, b, and c in Table C-4, respectively. Cap axial force due to pressure is included in service loads. Conservatively, deadweight is considered to act in the same direction as pressure and seismic loads.

Table C-5: Local Piping Loads Under Service Levels C.1.3 Primary Stress Intensity and Pure Shear Stress Calculation The primary stress intensities are calculated in the excel file at the inner radius, mean radius, and outer radius not including corrosion. The pure shear stresses are calculated in the excel file only at the outer radius of the IDTB weld, this calculation includes the effects of corrosion. The corrosion reduces the length of the weld along the head, ultimately reducing the area. All values are listed below including the stress ratio, which is calculated as shown below.

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP

=

Below are the general equations used to calculate the stresses:

( )

Axial stress: = + +

Hoop stress: = ( + 1)

Radial stress: = ( 1)

Shear stresses: = + , = =0 All the calculated stresses conservatively do not consider the support of the RVCH. The original CEDM nozzle is roll expanded, therefore the IDTB weld and nozzle only see a fraction of the stresses listed in Table C-6, Table C-7, and Table C-8.

Note membrane stresses are typically listed as average values. Being that membrane stresses are listed at all three locations they only need to meet criteria at the mean radius location.

Table C-6: Primary Stress Intensities at IDTB Weld Membrane

+ Membrane Service Level Location Stress Ratio Stress Ratio Bending (psi)

(psi)

Inside Level A Outside Mean Inside Level B Outside Mean Inside Level C Outside Mean Inside Level D Outside Mean Page 88

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table C-7: Pure Shear Stresses at IDTB Weld Shear Service Stress Location Stress Level Ratio (psi)

Level A Weld OD Level B Weld OD Level C Weld OD Level D Weld OD Table C-8: Primary Stress Intensities at CEDM Nozzle Membrane

+ Membrane Service Level Location Stress Ratio Stress Ratio Bending (psi)

(psi)

Inside Level A Outside Mean Inside Level B Outside Mean Inside Level C Outside Mean Inside Level D Outside Mean Both the IDTB weld and the CEDM nozzle met the primary stress intensity requirements at all locations and all service levels. In addition, the IDTB weld meets the pure shear requirements at all service levels.

C.1.4 Triaxial Stress Calculation To meet the requirement, Reference [1] states that the algebraic sum of the three primary stresses shall not exceed 4Sm, expect for service level D.

4 = 4(23,300 ) = 93,200 The three primary stresses that bound the IDTB weld and CEDM nozzle are: [

] The algebraic sum of the three primary stresses is [ ] Since [ ]

the triaxial stress requirement is met.

Page 89

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP C.2 Weld Size Requirements Weld Size (NB-3352.4, Reference [1])

This weld needs to satisfy the minimum dimension requirements of FIG. NB-4244(d)-1(c) per Reference [1]. FIG.

NB-4244(d)-1(c) is shown in Figure C-3. Reference [6] states the original CEDM nozzle has an OD of [

] and ID of [ ] which results in a nominal thickness of [ ] With the nominal thickness the weld size requirements can be determined. Table C-9 lists the IDTB weld size requirements and results. Figure C-4 shows how the weld size results are applicable to the requirements of NB-4244(d)-1(c).

Figure C-3: NB-4244(d)-1(c)

Page 90

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Table C-9: IDTB Weld Size Results Design Allowable Criteria IDTB Weld Formula Description Value Value met?

Yes Yes Yes Figure C-4: Weld Size Location Nozzle Diametric Clearance (NB-3337.3(a), Reference [1])

For a nozzle OD greater than 4 the maximum diametric clearance of 0.030 per NB-3337.3(a). Per Reference [6]

the replacement nozzle OD is [ ] and the bore ID is [ ] The equation below solves for the nozzle diametric clearance.

[ ]

Considering,

[ ]

Page 91

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP The nozzle diametric requirement is met. In addition, the original nozzle is roll expanded and therefore meets the requirements as well.

C.3 Tentative Thickness Calculation Tentative Thickness Calculation (NB-3324.1)

The tentative thickness calculation of the RVCH is determined by the methodology specified in NB-3324 of the ASME boiler and Pressure Vessel Code (Reference [1]). As stated in the article, except in local areas, the wall thickness of a vessel shall never be less than that obtained from the formula in NB-3324.1 for cylindrical shells and NB-3324.2 for spherical shells.

NB-3324.1 (Cylindrical Shells): =

NB-3324.2 (Spherical Shells): =

Where:

t = Tentative thickness, in.

P = Design pressure, psi R = Inside radius, in.

Sm = Design stress intensity value, psi C.3.1 RVCH Per Reference [4] the original RVCH inner radius is [ ] (including maximum tolerance) and the RVCH thickness is [ ] Using the spherical shell formula with P [ ] and Sm

[ ] the tentative pressure thickness is:

Comparing the design thickness to the tentative thickness.

[ ]

Therefore, the tentative thickness requirement is met.

C.3.2 CEDM Nozzle Per Reference [6], the original CEDM nozzle OD is [ ] and ID is [ ] Using the cylindrical shell formula with P [ ] R( [ ] ) and Sm ( [ ] ), the tentative pressure thickness is:

The nozzle wall thickness considering the nominal dimensions is:

[ ]

Page 92

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Therefore, the tentative thickness requirement is met.

C.4 Reinforcement Requirements Due to the area removal in the RVCH to accommodate the IDTB weld repair an evaluation is required to determine the reinforcement requirements are met.

The calculation for the minimum required area of reinforcement is based on the methodology listed in NB-3330 Reference [1]. Figure C-5 describes the dimensions and areas being analyzed.

Figure C-5: Reinforcement Area Calculation C.4.1 Removed Area The maximum penetration diameter including the effects of corrosion and dimensioning tolerances is:

do [ ]

This includes the corrosion rate of [ ] from Reference [16] over the life of [ ] (end of the plants license).

Page 93

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP The plane distance to the center of the penetration No. 46 (C) can be calculated by the x and y coordinated in Reference [4] to be:

C [ ]

The inside radius of the head (Ri) is [ ] (Reference [4]).

The mean radius of head:

R = Ri + t/2

[ ]

The minimum required thickness of the RVCH was previously calculated to be:

tt [ ]

The outside radius of the head to the required head thickness (Rt) is:

Rt = Ri + tt

[ ]

The vertical distance from center of head-to-head inside radius (Hi) is:

Hi = (Ri2 - C2)0.5

[ ]

The vertical distance from center of head to the outside radius of the required head thickness (Ht) is:

Ht = (Rt2 - C2)0.5

[ ]

Removed area due to opening (Arem) is:

Arem = (Ht - Hi)*do

[ ]

C.4.2 Limits of Reinforcement Reference [1] establishes the limits of the reinforcement area along and normal to the vessel surface. The limits of reinforcement, measured along the mid surface of the nominal wall thickness, shall meet the following:

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

a. NB-3334.1(a)(1), Diameter of finished opening, do [ ]

b. NB-3334.1(a)(2), Sum of radius of finished opening, thickness of nozzle (conservatively equal to zero) and vessel wall which equals [ ]

B. Two thirds of the required reinforcement shall be within a distance on each side of the axis of the opening equal to the greater of the following:

a. NB-3334.1(b)(1): r+0.5 (Rt)0.5 Where R is the mean radius of head, t is the nominal vessel wall thickness, and r is the radius of the finished opening in the corroded condition:

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Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP r+0.5 (Rt)0.5 [ ]

b. NB-3334.1(b)(2): r+2(t + tn)/3 Where r is the radius of the finished opening in the corroded condition, tn is the nozzle thickness (conservatively equal to zero) and t is the nominal vessel wall thickness:

r+2(t+ tn)/3 [ ]

Furthermore, the ASME code prohibits the same reinforcing material from being applied to more than one opening and requires that one half of the reinforcing material lie on each side of the opening. Therefore, the reinforcement limit is restricted to one-half of the distance between similar adjacent penetrations. Reference [4]

shows shortest distance to another opening from penetration No. 46 is [ ] Accordingly, the limit of reinforcement Lr is [ ]

C.4.3 Available Reinforcement Area The available area of reinforcement is shown in Figure C-5 and is calculated as follows:

The outside radius of the RVCH (Ro) is:

Ro = Ri + t

[ ]

The vertical distance from center of head to outside radius of the head (Ho) is:

Ho = (Ro2 - C2)0.5

[ ]

The thickness of the RVCH (tr) that was not removed is:

tr = Ho - Ht

[ ]

The area of the original flawed J-groove weld needs to be account for as area removed. It is conservatively estimated to be 3 in2. Conservatively, the IDTB weld is not being credited for area of reinforcement.

Ajgw [ ]

Total area removed is:

Aremoved = Arem + Ajgw

[ ]

Considering there are no other repairs in the vicinity of nozzle #46, the total area of reinforcement is:

Arein = 2*tr*(Lr - (do/2))

[ ]

Since the total reinforced area is greater than the total area removed the reinforcement requirements are met.

Page 95

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP APPENDIX D: POINTS OF INTEREST CONTOUR PLOTS The following contour plots are for paths WPath1a (outside node), WPath3b (inside node), and HPath2c (inside node). The stress intensity shown corresponds to the following event and load for each path where the stress intensity range is maximal.

ANSYS calculates the results by subtracting the component stresses of both time points and determines the stress intensity at the selected nodes.

Figure D-1: WPath1a and WPath3b, Event 1 Load 5 Page 96

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure D-2: WPath1a and WPath3b, Event 3 Load 29 Page 97

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure D-3: HPath2c, Event 2 Load 39 Page 98

Document No. 32-9354538-002 PROPRIETARY ASME Section III Stress & Fatigue Analysis for ANO-2 CEDM Half Nozzle Repair (Penetration 46) - NP Figure D-4: HPath2c, Event 4 Load 9 Page 99

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