RA-22-0106, Response to Request for Additional Information Regarding Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections

Response to Request for Additional Information Regarding Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections

ML22118A336
Person / Time
Site:	Robinson
Issue date:	04/28/2022
From:	Flippin N Duke Energy Progress
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML22118A335	List: RA-22-0106, Response to Request for Additional Information Regarding Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections
References
RA-22-0106 CPL-NRCD-RF-LR-000001 NP, Rev 0
Download: ML22118A336 (77)

Text

Nicole L. Flippin H. B. Robinson Steam Electric Plant Unit 2 Site Vice President Duke Energy 3581 West Entrance Road Hartsville, SC 29550 O: 843 951 1201 F: 843 857 1319 Nicole.Flippin@Duke-Energy.com PROPRIETARY INFORMATION - WITHHOLD UNDER 10 CFR 2.390 UPON REMOVAL OF ENCLOSURE 2 THIS LETTER IS UNCONTROLLED PROPRIETARY INFORMATION - WITHHOLD UNDER 10 CFR 2.390 UPON REMOVAL OF ENCLOSURE 2 THIS LETTER IS UNCONTROLLED Serial: RA-22-0106 10 CFR 50.90 April 28, 2022 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 H.B. Robinson Steam Electric Plant, Unit No. 2 Docket No. 50-261 Renewed License No. DPR-23

Subject:

Response to Request for Additional Information Regarding Application to Revise Technical Specifications to Adopt TSTF-577, Revised Frequencies for Steam Generator Tube Inspections By letter dated December 9, 2021 (Agencywide Document Access and Management System (ADAMS) Accession No. ML21343A047), as supplemented by letter dated January 6, 2022 (ADAMS Accession No. ML22006A240), Duke Energy Progress, LLC (Duke Energy) requested an amendment to the H.B. Robinson Steam Electric Plant, Unit No. 2 (HBRSEP2) Technical Specifications (TS). The proposed amendment would adopt Technical Specifications Task Force (TSTF) Traveler TSTF-577, Revision 1, Revised Frequencies for Steam Generator Tube Inspections. Additionally, Duke Energy proposed a steam generator tube inspection period of 72 effective full power months (EFPM) for the HBRSEP2 inspection period that began December 8, 2020.

The U.S. Nuclear Regulatory Commission (NRC) staff reviewed the proposed amendment and determined additional information is needed to complete their review. Duke Energy received the request for additional information (RAI) from the NRC through electronic mail on March 18, 2022 (ADAMS Accession No. ML22080A004).

provides Duke Energys responses to RAI-1c, 2a, 6, 7 and 8. Enclosure 2 provides responses to RAI-1a, 1b, 1d, 2b, 3, 4 and 5 which contain information proprietary to Westinghouse Electric Company LLC (Westinghouse), and the information is supported by an Affidavit (Attachment 4) signed by Westinghouse, the owner of the information. The Affidavit sets forth the basis on which the information may be withheld from public disclosure by the NRC and addresses with specificity the considerations listed in Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Section 2.390, Public inspections, exemptions, requests for

PROPRIETARY INFORMATION - WITHHOLD UNDER 10 CFR 2.390 UPON REMOVAL OF ENCLOSURE 2 THIS LETTER IS UNCONTROLLED U.S. Nuclear Regulatory Commission RA-22-0106 Page 2 withholding." Accordingly, it is respectfully requested that the information which is proprietary to Westinghouse be withheld from public disclosure in accordance with 10 CFR Section 2.390.

A non-proprietary version of Enclosure 2 is included in Enclosure 3. The information contained within Enclosures 1 and 2 does not change the No Significant Hazards Consideration provided in the original license amendment request (LAR) submittal. provides a revised markup of the TS pages. This markup supersedes the TS markup provided in the original LAR, entirely. Attachment 2 provides revised (clean) TS pages that reflect the proposed change. Attachment 3 provides a copy of the Refueling Outage 32 Condition and Monitoring Assessment reference requested by the NRC staff in RAl-2a.

There are no regulatory commitments made in this submittal.

In accordance with 10 CFR 50.91, Duke Energy is notifying the State of South Carolina of the supplement to this LAR by transmitting a copy of this letter and enclosure to the designated State Official.

If there are any questions or if additional information is needed, please contact Mr. Lee Grzeck, Manager-Nuclear Fleet Licensing (Acting) at 980-373-1530.

I declare under penalty of pe~ury that the foregoing is true and correct. Executed on April 28, 2022.

Sincerely, Nicole L. Flippin Site Vice President

Enclosures:

1. Response to Request for Additional Information RAl-1 c, 2a, 6, 7, 8

2. Response to Request for Additional Information RAl-1a, 1b, 1d, 2b, 3, 4, 5 (Westinghouse Proprietary)

3. Response to Request for Additional Information RAl-1a, 1 b, 1 d, 2b, 3, 4, 5 (Redacted)

Attachments:

1. Revised Technical Specifications Markup

2. Revised (Clean) Technical Specifications Pages

3. Reference 6 from the RO32 Condition Monitoring and Operational Assessment:

"Disposition of Foreign Object(s) Remaining in HB Robinson RSGs (Post-Secondary Side Inspection 2RFO 32)"

4. Affidavit of Westinghouse PROPRIETARY INFORMATION - WITHHOLD UNDER 10 CFR 2.390 UPON REMOVAL OF ENCLOSURE 2 THIS LETTER IS UNCONTROLLED

PROPRIETARY INFORMATION - WITHHOLD UNDER 10 CFR 2.390 UPON REMOVAL OF ENCLOSURE 2 THIS LETTER IS UNCONTROLLED U.S. Nuclear Regulatory Commission RA-22-0106 Page 3 PROPRIETARY INFORMATION - WITHHOLD UNDER 10 CFR 2.390 UPON REMOVAL OF ENCLOSURE 2 THIS LETTER IS UNCONTROLLED cc (with Enclosures/Attachments):

L. Dudes, USNRC Region II - Regional Administrator M. Fannon, USNRC Senior Resident Inspector - RNP T. Hood, NRR Project Manager - RNP A. Nair, Director, Division of Environmental Response (SC)

A. Wilson, Attorney General (SC)

L. Garner, Manager, Radioactive and Infectious Waste Management (SC)

RA-22-0106 Response to Request for Additional Information RAI-1c, 2a, 6, 7, 8

[5 pages follow this cover page]

RA-22-0106 Page 1 Request for Additional Information (RAI)

By letter dated December 9, 2021, as supplemented by letter dated January 6, 2022 (Agencywide Documents Access and Management System Accession No. ML21343A047 and ML22006A240, respectively), Duke Energy Progress, LLC (the licensee) submitted a license amendment request for H.B. Robinson Steam Electric Plant, Unit No. 2 (Robinson). The proposed amendment would adopt Technical Specifications Task Force (TSTF) Traveler TSTF 577, Revision 1, Revised Frequencies for Steam Generator Tube Inspections (ADAMS Accession No. ML21060B434).

Title 10 of the Code of Federal Regulations (10 CFR) Part 50, Domestic Licensing of Production and Utilization Facilities, Section 50.36, Technical specifications, establishes the regulatory requirements related to the content of Technical Specifications (TSs). Section 50.36(c)(5), Administrative Controls, states in part, that [a]dministrative controls are the provisions relating to organization and management, procedures, recordkeeping, review and audit, and reporting necessary to assure operation of the facility in a safe manner. All pressurized water reactors have TSs according to 10 CFR 50.36 that include a steam generator (SG) Program with specific criteria for the structural and leakage integrity, repair, and inspection of SG tubes. At Robinson, programs established, including the SG Program, are listed in the administrative controls section of the TS to operate the facility in a safe manner.

The U.S. Nuclear Regulatory Commission staff has reviewed the information submitted by Duke Energy and determined that additional information is required to complete its review. The specific request for additional information is addressed below.

RAI-1

Discuss in greater detail how potential cracking at tube support plates (TSPs) was analyzed, including:

a. Did the analysis consider cracking only in the high stress tubes or a greater subpopulation of tubes? If tubes that were inspected with the bobbin probe only were included in the subpopulation of potentially susceptible tubes, please discuss how these tubes were analyzed and combined with those tubes inspected with a combination bobbin probe/array probe to develop the overall probability of burst and probability of leakage.

b. Provide more details about how the undetected total flaw length distribution was derived from industry experience for potential axial outside diameter stress corrosion at the expansion transition (ODSCC) at the TSP.

c. Compare the tube support plate deposits at Robinson relative to the Duke unit that experienced cracking in a few non-high stress tubes in 2019 near the top of a TSP. Discuss the likelihood of similar tube cracking at Robinson based on deposit amounts or composition.

d. Provide the 95th percentile probability of detection value for the bobbin probe and the combined bobbin-array probe.

RA-22-0106 Page 2 Duke Energy Response to RAI-1a The response to RAI-1a is provided in Enclosure 2 (Westinghouse proprietary). A redacted version of the response is provided in Enclosure 3.

Duke Energy Response to RAI-1b The response to RAI-1b is provided in Enclosure 2 (Westinghouse proprietary). A redacted version of the response is provided in Enclosure 3.

Duke Energy Response to RAI-1c A deposit minimization treatment (DMT) was performed for Robinson at EOC-28 in 2013 removing approximately 4,500 pounds of deposit. The total estimated deposit currently in the Robinson steam generators is approximately 4,400 pounds.

In contrast, the other referenced Duke Energy unit (i.e., Catawba Unit 2) had an estimated greater than 10,000 pounds of deposit at EOC-23 when the observation was made. The Catawba unit had never been chemically cleaned. The Catawba unit was subsequently cleaned (DMT) at EOC-24. The Robinson steam generators are a feedring design, whereas the Catawba Unit 2 steam generators are a preheater design. The deposits will not accumulate the same between the two designs. Based on differences in design and deposit loading between the two plants, conditions are not expected to be the same.

Duke Energy Response to RAI-1d The response to RAI-1d is provided in Enclosure 2 (Westinghouse proprietary). A redacted version of the response is provided in Enclosure 3.

RAI-2

During Refueling Outage 32 (RO32), 20 new foreign object wear indications were detected. A significant number of these indications occurred at support plates with the largest measured at 30-31 percent through wall (TW). No possible loose part signals were detected in any of the tubes with foreign object wear. In addition, four previous indications of foreign object wear without associated possible loose part signals exhibited 1-3 percent TW/effective full power years (EFPY) growth since the previous inspection.

a. Provide a copy of Reference 6 from the RO32 Condition Monitoring and Operational Assessment: Disposition of Foreign Object(s) Remaining in Robinson RSGs.

b. Discuss for each of the four indications mentioned above that exhibited growth, whether the measured growth is judged to result from eddy current measurement uncertainty or additional wear from a loose part that did not produce a possible loose part indication. Discuss why loose part wear is not expected to challenge tube integrity during a 72 EFPY months inspection cycle.

RA-22-0106 Page 3 Duke Energy Response to RAI-2a A copy of Reference 6 is provided as Attachment 3 to this submittal.

Duke Energy Response to RAI-2b The response to RAI-2b is provided in Enclosure 2 (Westinghouse proprietary). A redacted version of the response is provided in Enclosure 3.

RAI-3

Please provide insights as to why the array probe 95th percentile probability of detection for circumferential ODSCC cracking in the tubesheet expansion zone is more favorable than for axial ODSCC cracking. Is the probability of detection for axial cracks at the tubesheet expansion zone more favorable than circumferential cracks when the cracks are smaller?

Duke Energy Response to RAI-3 The response to RAI-3 is provided in Enclosure 2 (Westinghouse proprietary). A redacted version of the response is provided in Enclosure 3.

RAI-4

Page 2 of Attachment 3 in the license amendment request (LAR) states: Recent (April 2021) operating experience within the Duke Energy fleet at Catawba Nuclear Station, Unit 2 demonstrated that an inspection using enhanced probes did not identify additional crack like indications. The NRC staff interprets this statement to mean that the use of the array probe, in addition to the bobbin probe, does not necessarily mean that additional cracks will be detected.

Please confirm if the NRC staffs understanding is corret and discuss the relative crack detection capability of the array probe as compared to the bobbin only probe.

Duke Energy Response to RAI-4 The response to RAI-4 is provided in Enclosure 2 (Westinghouse proprietary). A redacted version of the response is provided in Enclosure 3.

RAI-5

The NRC staff noted in the supplemental letter dated January 6, 2022 potential typographical errors. Please assess and correct any typographical errors in the following items:

a. Table 2-3, the indication location (01C +51.21) shown for Tube R6 C76 in SGC.

b. Section 4.1, Anti-Vibration Bars Wear maximum growth occurred at multiple indications, which exhibited growth of 2.0 percent TW, or 0.91 percent TW/EFPY.

c. Section 4.5 inspection interval of 4.0 EFPY covering three cycles of operation to RO34

RA-22-0106 Page 4

d. Section 4.5.1, the performance criteria was also met for a total duration of 4.0 EFPY until RO24.

e. Section 4.5.2, therefore, circumferential ODSCC, at the hot expansion transition meets the OA performance criteria for structural and leakage integrity for two and three full cycles of operation.

f.

Section 4.5.3, The performance criteria was also met for a total duration of 4.0 EFPY until RO24.

g. Section 4.5.3, in the paragraph following Table 4-4, the POL of 0.936%

corresponds to three cycles.

Duke Energy Response to RAI-5 The response to RAI-5 (all parts) is provided in Enclosure 2 (Westinghouse proprietary). A redacted version of the response is provided in Enclosure 3.

RAI-6

The LAR description of TS 5.5.9.d introductory paragraph does not appear to align with the current TS description. For example, the LAR version of the last sentence in TS 5.5.9.d introductory paragraph, states, An degradation assessment whereas the current TS states, A degradation assessment (emphasis added). This change was not identified as a variation and appears to be a typographical error that was introduced when preparing LAR Attachments 1 (proposed TS changes) and 2 (revised TS pages). Please assess and correct any typographical errors.

Duke Energy Response to RAI-6 The existing Robinson TS 5.5.9.d correctly states A degradation assessment in the introductory paragraph. The proposed change in the original license amendment request incorrectly stated An degradation assessment in the TS markups (Attachment 1) and re-typed pages (Attachment 2). Attachments 1 and 2 of this submittal reflect A degradation assessment in the introductory paragraph of TS 5.5.9.d.

RAI-7

TS 5.5.9.d would be revised by adding a phrase regarding portions of the tube that are exempt from inspection by alternate repair criteria (see LAR Attachment 1, INSERT 1). However, LAR INSERT 1 appears to contain additional punctuation (unnecessary comma between outlet and except) that is not consistent with TSTF-577. Please assess and correct any typographical errors.

Duke Energy Response to RAI-7 Duke Energy proposes to remove the comma between outlet and except to be consistent with the TSTF-577 Traveler. Attachments 1 and 2 of this submittal reflect removal of the comma.

RA-22-0106 Page 5

RAI 8

TS 5.5.9.d.3 would be revised by adding a phrase regarding portions of the tube that are exempt from inspection by alternate repair criteria that replaces the phrase not excluded above (see LAR Attachment 1, INSERT 3). However, LAR INSERT 3 appears to contain additional punctuation (unnecessary comma between tube and excluding) that is not consistent with TSTF-577. Please assess and correct any typographical errors.

Duke Energy Response to RAI-8 Duke Energy proposes to remove the comma between tube and excluding to be consistent with the TSTF-577 Traveler. Attachments 1 and 2 of this submittal reflect removal of the comma.

RA-22-0106 Response to Request for Additional Information RAI-1a, 1b, 1d, 2b, 3, 4, 5 (Westinghouse Proprietary)

[13 pages follow this cover page]

RA-22-0106 Response to Request for Additional Information RAI-1a, 1b, 1d, 2b, 3, 4, 5 (Redacted)

[13 pages follow this cover page]

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 1 of 13 Rev. 0 Westinghouse Electric Company CPL-NRCD-RF-LR-000001 NP-Attachment Revision 0 H.B. Robinson Steam Electric Plant, Unit 2-Responses to NRC Request for Additional Information from the Application to Adopt Technical Specifications Task Force (TSTF)

Frequencies for Steam Generator Tube April 2022 Author:

Jay R. Smith*

Component Design and Management Programs Verifier:

Levi Y. Marcus*

Component Design and Management Programs Reviewer:

Gary W. Whiteman*

Licensing Engineering Approved:

Robert S. Chappo, Jr.*, Manager Component Design and Management Programs

©2022 Westinghouse Electric Company LLC All Rights Reserved

• Electronically approved records are authenticated in the Electronic Document Management System.

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 2 of 13 Rev. 0 H.B. Robinson Steam Electric Plant, Unit 2-Responses to NRC Request for Additional Information from the Application to Adopt Technical Specifications DAMS Accession No. ML21060B434)

Background

By letter dated December 9, 2021, as supplemented by letter dated January 6, 2022 (Agencywide Documents Access and Management System Accession No. ML21343A047 and ML22006A240, respectively), Duke Energy Progress, LLC submitted a license amendment request for H.B. Robinson Steam Electric Plant, Unit No. 2 (Robinson). The proposed amendment would adopt Technical Title 10 of the Code of Federal Re estic Licensing of Production and related to the content of Technical Specifications (T e provisions relating to organization and management, procedures, recordkeeping, review and audit, and reporting necessary to assure operation of the facility in according to 10 CFR 50.36 that include a steam generator (SG) Program with specific criteria for the structural and leakage integrity, repair, and inspection of SG tubes. At Robinson, programs established by Duke Energy Progress, LLC, including the SG Program, are listed in the administrative controls section of the TS to operate the facility in a safe manner.

The U.S. Nuclear Regulatory Commission staff has reviewed the information submitted by Duke Energy Progress, LLC and determined that additional information is required to complete its review. Responses to the specific requests for additional information are provided below.

Responses to Request for Additional Information In order to complete the review of the License Amendment Request (LAR), the Nuclear Regulatory Commission (NRC) Staff has requested the following information:

RAI-1

Discuss in greater detail how potential cracking at tube support plates (TSPs) was analyzed, including:

a. Did the analysis consider cracking only in the high stress tubes or a greater sub-population of tubes? If tubes that were inspected with the bobbin probe only were included in the subpopulation of potentially susceptible tubes, please discuss how these tubes were analyzed and combined with those tubes inspected with a combination bobbin probe/array probe to develop the overall probability of burst and probability of leakage.

Response

The Robinson Refueling Outage 32 (RO32) condition monitoring and operational assessment (Reference

1) performed forward-looking tube burst and leakage projections for a 3-cycle inspection interval following RO32 for three potential degradation mechanisms that were judged to be more likely to occur

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 3 of 13 Rev. 0 based on operating experience of similar plants. H.B. Robinson has no history of tube cracking in any location. The three potential degradation mechanisms evaluated in the RO32 CMOA (Reference 1) were axial and circumferential outer diameter stress corrosion cracking (ODSCC) at tubesheet expansion transitions and axial ODSCC at tube support plate (TSP) intersections. The focus of this response is ODSCC at TSP intersections in Alloy 600 thermally treated (A600TT) tubes with potentially high residual stress from cold working during fabrication.

A fully probabilistic operational assessment (OA) has been performed following the guidance in the Reference 2 EPRI SG Integrity Assessment Guidelines (IAGL) and an updated evaluation is described in detail in the response to RAI Question #1b. An input to the fully probabilistic analysis is the assumed population of undetected flaws and flaws assumed to initiate during the subsequent inspection interval.

The population of tubes considered in the RO32 CMOA for axial ODSCC at TSP intersections was the total population of high stress tubes identified at Robinson. The total population of high stress tubes was assumed to be in a single SG and assumed four TSP intersections per tube were susceptible. This assumption resulted in evaluating four times the actual number of high stress tubes identified and applied all to a single steam generator. For Robinson, axial ODSCC at TSP locations in non-residual stressed cold worked tubes was characterized as a potential degradation mechanism less likely to occur than the three mechanisms in evaluated in the RO32 CMOA. This conclusion was based on industry experience of cracking in A600TT tubed SGs presented in the Reference 5 EPRI Feasibility Study for Multi-Cycle 600TT Operational Assessments (EPRI Feasibility Study) that all traditional axial ODSCC flaws at TSP intersections (81 indications) have been within cold worked tubes with potential higher residual stress.

Traditional axial ODSCC flaws were defined as cracking directly underneath the TSP land and initiating near the center of the TSP width. More recent industry experience showed two occurrences of non-traditional cracking in broached TSP flow holes and just above a TSP in the freespan in non-stressed tubes. These indications were believed to be related to deposit conditions and not due to the stress condition. The deposit related cracking mechanism was also considered a degradation mechanism less likely to occur than the three mechanisms evaluated in the RO32 CMOA. Additionally, Robinson operating temperature (605°F) is significantly less than other A600TT plants that have experienced cracking at TSP locations (611°F to 621°F), thus reducing the susceptibility to cracking.

b. Provide more details about how the undetected total flaw length distribution was derived from industry experience for potential axial outside diameter stress corrosion at the TSP.

Response

The undetected total flaw length distribution for axial ODSCC at TSP intersections was derived from reanalysis of +POINT probe data from similar plants that had experienced axial ODSCC at TSP intersections. The total flaw length data set consisted of 81 indications from domestic plants with thermally treated Alloy 600 (A600TT) tubed SGs as provided in the EPRI Feasibility Study (Reference 5). The flaws were sized with Electric Power Research Institute (EPRI) +POINT probe sizing eddy current examination technique specification sheet (ETSS) I28432 applicable to axial ODSCC at broached TSP intersections. Subsequent review of the RO32 CMOA methodology for the degradation mechanism revealed that the distribution of non-destructive examination (NDE) measured total lengths was used as the end-of-cycle (EOC) distribution without adjustment. However, when using NDE measured flaw data

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 4 of 13 Rev. 0 for OA calculations it is standard practice to adjust the NDE flaw sizes by the mean sizing regression to 48 effective full power months (EFPM), further flaw growth should be considered. Both of these practices were not applied in the Reference 1 OA for this degradation mechanism. These issues were entered into the Westinghouse Corrective Action Program and the OA was reperformed using a redefined total flaw length distribution and the results presented in this response.

The re-calculation of the OA for axial ODSCC at TSP intersections used a total length flaw distribution derived from the industry A600TT +POINT probe sizing of 81 detected flaws adjusted for NDE measurement uncertainty and included a 1-cycle (2.0 EFPY) growth allowance.

In addition to updating the total flaw length distribution, the recalculation of the RO32 CMOA (Reference

1) also updated the array probe maximum depth probability of detection (POD) curve with recently published EPRI methodology for developing array probe PODs as provided in the Reference 4 EPRI Plus-Point to X-Probe Amplitude Transfer Function and Probability of Detection report (EPRI Transfer Function Report). The original POD curve for axial ODSCC at TSP intersections described in the Reference 1 RO32 CMOA was developed using the array probe ETSS 20402.1 data set which was very limited in the number of detected flaws (12) and limited in flaw size (62%TW to 97%TW). This produced a very conservative and steep array probe POD curve due to the lack of Ahat data points below 62%TW. The 95th and 50th percentiles of the original POD curve were 83%TW and 56%TW, respectively. The Reference 4 EPRI Transfer Function Report describes a methodology to correlate

+POINT probe voltage amplitudes to array probe voltage amplitudes using a transfer function. This produces additional data necessary to generate more accurate and reliable array probe POD curves by providing Ahat data for flaws below 62%TW. Using the EPRI Transfer Function Report methodology, a more robust flaw Ahat data set was generated using 60 axial ODSCC flaws ranging from 22%TW to 99%TW to generate a noise-based array probe POD using the Robinson RO32 array probe TSP noise distribution. The resultant array probe maximum depth POD curve for axial ODSCC at TSP intersections has a 95th percentile of 74%TW and a 50th percentile of 37%TW as shown in Figure 1.

A fully probabilistic OA was performed using the updated total length distribution and the updated array probe POD curve (Figure 1) as described above. The undetected maximum depth distribution that was input to the OA was derived from processing a random distribution of flaws up to 100%TW through the bobbin coil ETSS I28413 logistic POD and the updated array probe POD shown in Figure 1, since all high stress tubes were inspected with both probe types. The EPRI typical flaw growth rates for maximum depth and total length were applied. As described above, a 2.0 EFPY growth allowance was applied to the total length distribution since a detected flaw length distribution was used as the BOC distribution.

The population of flaws and flaw initiation rate inputs used are described in the response to RAI Question

1. 1a. The 3-cycle (72 EFPM) fully probabilistic OA resulted in a probability of burst of 3.78% and a probability of accident induced leakage of 2.42%, thus satisfying the <5% probability acceptance criteria (see Table 1).

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 5 of 13 Rev. 0 Table 1: Axial ODSCC at TSPs FBM Simulation Results Summary Number of Non-Detected Flaws Cycle Duration (EFPY)

Number of Cycles Prob. of Burst (POB)

Prob. of Leakage (POL)

Burst Pressure at Lower 5%

Leak Rate at Lower 5%

2 2.0 EFPY 3

3.78%

2.42%

4865 psi 0.0 gpm Acceptance Criterion 5%

5%

4650 psi 0.06 gpm Figure 1. Site Specific Maximum Depth Array Probe POD for Axial ODSCC at TSP Intersections

c. Compare the tube support plate deposits at Robinson relative to the Duke unit that experienced cracking in a few non-high stress tubes in 2019 near the top of a TSP. Discuss the likelihood of similar tube cracking at Robinson based on deposit amounts or composition.

Response

Duke Energy Progress, LLC to provide response.

a,c,e

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 6 of 13 Rev. 0

d. Provide the 95th percentile probability of detection value for the bobbin probe and the combined bobbin-array probe.

Response

POD curves are used in fully probabilistic operational assessments to determine the undetected flaw size distribution for the inspection techniques used to detect the degradation mechanism. For the Robinson potential degradation mechanism of axial ODSCC at TSP intersections, all high stress tubes were inspected with both the bobbin coil probe and the array probe. The inspection with two different probe designs can result in improved overall detection capabilities afforded by the individual features of each probe type and techniques. As an example, a flaw may not be detected by one probe type but could be detected by the second probe type. For inspections with two probe types, in this case the bobbin coil and the array probe, a singular combined bobbin-array POD was not developed to derive the undetected flaw size distribution for input to the OA model; instead, [

]a,c,e Detection of axial ODSCC flaws at TSP intersections with the bobbin coil probe is accomplished using EPRI ETSS I28413. The maximum depth 95th percentile value from the ETSS I28413 logistic POD curve is 79.5%TW.

Detection of axial ODSCC flaws at TSP intersection with the array probe is accomplished using EPRI ETSS 20402.1. Development of the POD is provided in RAI Question #1a. The maximum depth 95th percentile value from the array probe POD curve shown in Figure 1 is 74%TW.

[

]a,c,e that has a 95th percentile value of 40.3%TW.

RAI-2

During Refueling Outage 32 (RO32), 20 new foreign object wear indications were detected. A significant number of these indications occurred at support plates with the largest measured at 30-31 percent through wall (TW). No possible loose part signals were detected in any of the tubes with foreign object wear. In addition, four previous indications of foreign object wear without associated possible loose part signals exhibited 1-3 percent TW/effective full power years (EFPY) growth since the previous inspection.

a. Provide a copy of Reference 6 from the RO32 Condition Monitoring and Operational

Response

Duke Energy Progress, LLC to provide response.

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 7 of 13 Rev. 0

b. Discuss for each of the four indications mentioned above that exhibited growth, whether the measured growth is judged to result from eddy current measurement uncertainty or additional wear from a loose part that did not produce a possible loose part indication. Discuss why loose part wear is not expected to challenge tube integrity during a 72 EFPM inspection cycle.

Response

All four of the indications that exhibited growth were reevaluated and show no change between RO30 and RO32. Since these four indications did not have a PLP detected by eddy current and showed no change in depth from the previous eddy current inspection, loose part wear is not expected to challenge tube integrity during a 72 EFPM inspection cycle.

RAI-3

Please provide insights as to why the array probe 95th percentile probability of detection for circumferential ODSCC cracking in the tubesheet expansion zone is more favorable than for axial ODSCC cracking. Is the probability of detection for axial cracks at the tubesheet expansion zone more favorable than circumferential cracks when the cracks are smaller?

Response

The primary elements and inputs for developing probability of detection (POD) curves include the flaw metallurgical depth to flaw voltage amplitude regression (Ahat) for the degradation mechanism and the eddy current noise voltage amplitude distribution for the region of interest. The Ahat regression and noise distribution are probabilistically sampled to calculate flaw signal-to-noise (S/N) ratios which are used to determine whether sampled flaw depths are detected or not detected. The detected and non-detected flaw sizes are used to develop the POD curve. Larger S/N ratios tend to result in more flaw detection and thus more favorable POD curves. Larger S/N ratios occur from larger flaw signals from the Ahat regression or from smaller noise signals from the noise distribution.

The tubesheet expansion transition noise measurements and distributions used in the Reference 1 RO32 CMOA were collected with the array probe during the Robinson RO32 outage. The array probe contains axial sensitive coils and circumferential sensitive coils. Consequently, two noise distributions were developed, a noise distribution for axially oriented flaws and a noise distribution for circumferentially oriented flaws. The axial noise distribution contained higher noise levels than the circumferential noise distribution. The 95th percentile of the axial noise distribution was 0.34 volts as compared to 0.27 volts for the circumferential noise distribution. Therefore, the probability of detection would be more favorable for circumferential flaws at the tubesheet expansion transition based upon the noise levels.

The Ahat array probe regressions for axial and circumferential ODSCC at tubesheet expansion transitions that were used in the Reference 1 RO32 CMOA were compared for trends that could explain differences in POD impact for axial and circumferential flaws. The Ahat comparison showed that the circumferential ODSCC Ahat regression has larger flaw voltages than the axial ODSCC Ahat for same sized flaws up to about 94% TW, where the two regressions cross. The larger circumferential ODSCC Ahat regression would also produce more favorable probability of detection than for axial ODSCC.

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 8 of 13 Rev. 0 The higher noise level for the axial sensitive array probe coils and larger Ahat regression for the circumferential sensitive coils could be explained by the array probe design. The array probe consists of two bands of axial sensitive and circumferential sensitive coils. Multiple coils of each type are placed around the circumference of the probe to provide 360-degree coil coverage. [

]a,c,e Given the higher voltage amplitude noise levels from the array probe axial sensitive coils and the lower Ahat flaw depth to voltage correlation than the array probe circumferential sensitive coils, the probability of detection for shallow axial flaws would be expected to be less favorable than for circumferential flaws of the same depth. This conclusion is demonstrated through comparison of axial and circumferential probability of detection curves developed from the recent EPRI Transfer Function Report (Reference 4) derivations of Ahat regressions and the noise-based Model Assisted Probability of Detection (MAPOD) methodology using RO32 axial and circumferential noise distributions. Figure 2 provides the developed log-logistic and logistic probability of detection curves for axial and circumferential ODSCC flaws at the tubesheet expansion transition using the array probe.

Figure 2 shows that the circumferential ODSCC probability of detection is more favorable than the axial probability of detection for both the log-logistic and logistic POD functions for flaw depths larger than about 25%TW. For shallower depths less than about 25%TW the axial and circumferential flaw POD functions are similar. It is noted from Figure 2 that the log-logistic POD functions are less favorable than the logistic POD functions for larger flaw depths and the log-logistic function slope becomes nearly flat also for larger flaw depths. This is because the log-logistic function passes the curve through the origin (0, 0) which artificially lowers the tail of the curve at larger depths. The logistic POD function does not artificially pass through the origin but allows the curve to become negative. Therefore, the logistic curve is considered more accurate for larger flaw depths. It is believed that the reason for the axial and circumferential POD curves are similar for shallow depths is due to decreased sensitivity of both coil orientations for shallow depths (i.e., both coil orientations have difficulty detecting flaws with shallow depths).

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 9 of 13 Rev. 0 Figure 2. Axial and Circumferential ODSCC at Expansion Transition POD

RAI-4

Page 2 of Attachment 3 in the license amendment re experience within the Duke Energy fleet at Catawba Nuclear Station, Unit 2 demonstrated that an inspection using enhanced probes did not identify interprets this statement to mean that the use of the array probe, in addition to the bobbin probe, does not necessarily mean that additional cr is correct and discuss the relative crack detection capability of the array probe as compared to the bobbin only probe.

Response

(April 2021) operating experience within the Duke Energy fleet at Catawba Nuclear Station, Unit 2 demonstrated that an inspection using enhanced probes is statement was intended to be a statement of fact that during the April 2021 Catawba Unit 2 inspection the array probe did not identify additional crack like flaws that were not detected by the bobbin coil probe. The bobbin coil probe also did not identify crack-like flaws during this inspection.

The detection of cracks is dependent on various factors including the crack size and the inspection probe.

There is an increasing probability of detecting a flaw as the flaw size increases as represented in a POD a,c,e

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 10 of 13 Rev. 0 curve. A defined probability of flaw detection or non-detection for each probe type can be determined for a given flaw depth. Each probe type has a specific probability of detecting or not detecting the same flaw. Therefore, there are three outcomes of flaw detection when inspected by both probes: 1) the flaw is detected by both probes, 2) the flaw is detected by one probe and not the other, and 3) the flaw is not detected by either probe. If no flaws are detected by either probe it may also signify that there were no understanding is correct in that use of the array probe in addition to the bobbin probe does not necessarily mean that more cracks will be detected.

The bobbin coil probe and array probe are both qualified to detect axial ODSCC at TSP intersections, but the designs and techniques differ. The bobbin coil probe contains two circumferentially wound coils that produce magnetic fields that can detect flaws in the differential mode which detects field variations between the two probe coils and in the absolute mode which detects field variations from one coil on the probe to a reference probe outside the tube. The bobbin coil detects magnetic field variations due to flaws for the entire tube circumference without the ability to distinguish multiple flaws at the same elevation.

Due to the coil winding and magnetic field orientation, the bobbin coil can detect axial and volumetric flaws but not circumferentially oriented flaws. The array probe contains two bands of multiple coil pairs that are spaced circumferentially around the entire circumference of the probe. Each coil pair consists of a magnetic field driver coil and a pickup coil. The array probe has one ring of coil pairs to provide detection capability for axial oriented flaws and one ring for circumferentially oriented flaws. The array probe can discern multiple flaws at the same elevation. Although the bobbin coil probe and array probe are designed to detect flaws differently, both probes are qualified to the same minimum acceptance standards and detection requirements provided in the EPRI Steam Generator Examination Guidelines (Reference 3). Therefore, the probability of detection of each probe type is expected to be similar. Figure 3 provides a comparison of the POD curves for the bobbin coil and array probes for axial ODSCC at TSP intersections. Figure 3 shows that the POD curves are similar, but the array probe provides more favorable detection at larger depths than the bobbin coil probe.

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 11 of 13 Rev. 0 Figure 3. Bobbin Coil and Array Probe POD Comparison, Axial ODSCC at TSP Intersections

RAI-5

The NRC staff noted in the supplemental letter dated January 6, 2022 potential typographical errors.

Please assess and correct any typographical errors in the following items:

a. Table 2-3, the indication location (01C +51.21) shown for Tube R6 C76 in SGC.

Response: The location is correct at 0.6 inches below the second tube support plate.

b. Section 4.1, Anti-Vibration Bars Wear maximum growth occurred at multiple indications, which exhibited growth of 2.0 percent TW, or 0.91 percent TW/EFPY.

Response: The maximum growth of 3% TW occurred at a single location, SG C R35 C61 03A, which results in a growth rate of 0.91 %TW/EFPY

c. Section 4.5 inspection interval of 4.0 EFPY covering three cycles of operation to RO34 Response: An inspection interval of 4.0 EFPY was applied for evaluations covering two cycles of operation to RO34.

d. Section 4.5.1, the performance criteria was also met for a total duration of 4.0 EFPY until RO24.

Response: the performance criteria was also met for a total duration of 4.0 EFPY until RO34.

a,c,e

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 12 of 13 Rev. 0

e. Section 4.5.2, therefore, circumferential ODSCC, at the hot expansion transition meets the OA performance criteria for structural and leakage integrity for two and three full cycles of operation.

Response: therefore, axial ODSCC, at the hot expansion transition meets the OA performance criteria for structural and leakage integrity for two and three full cycles of operation.

f. Section 4.5.3, The performance criteria was also met for a total duration of 4.0 EFPY until RO24.

Response: The performance criteria was also met for a total duration of 4.0 EFPY until RO34.

g. Section 4.5.3, in the paragraph following Table 4-4, the POL of 0.936% corresponds to three cycles.

Response: The POL of 0.936% corresponded to two cycles. Note that the POL values have been updated in the response to RAI Question #1b (Table 1).

RAI-6

The LAR description of TS 5.5.9.d introductory paragraph does not appear to align with the current TS description. For example, the LAR version of the last sentence in TS 5.5.9.d introductory paragraph, (emphasis added). This change was not identified as a variation and appears to be a typographical error that was introduced when preparing LAR Attachments 1 (proposed TS changes) and 2 (revised TS pages).

Please assess and correct any typographical errors.

Response

Duke Energy Progress, LLC to provide response.

RAI-7

TS 5.5.9.d would be revised by adding a phrase regarding portions of the tube that are exempt from inspection by alternate repair criteria (see LAR Attachment 1, INSERT 1). However, LAR INSERT 1 appears to contain additional punctuation (unnecessary co consistent with TSTF-577. Please assess and correct any typographical errors.

Response

Duke Energy Progress, LLC to provide response.

Westinghouse Non-Proprietary Class 3 CPL-NRCD-RF-LR-000001 NP-Attachment Page 13 of 13 Rev. 0

RAI-8

TS 5.5.9.d.3 would be revised by adding a phrase regarding portions of the tube that are exempt from inspection by alternate repair criteria that replace 1, INSERT 3). However, LAR INSERT 3 appears to contain additional punctuation (unnecessary comma istent with TSTF-577. Please assess and correct any typographical errors.

Response

Duke Energy Progress, LLC to provide response.

References

1. Westinghouse Report SG-CDMP-20-25, Revision Generator Condition Monitoring and Final

2. Steam Generator Management Program: Steam Generator Integrity Assessment Guidelines, Revision 4. EPRI, Palo Alto, CA: 2016. 3002007571.

3. Steam Generator Management Program: Pressurized Water Reactor Steam Generator Examination Guidelines: Revision 8, EPRI, Palo Alto, CA: 2016. 3002007572.

4.

X-Probe Amplitude Transfer Function and

5. Steam Generator Management Program: Feasibility Study for Multi-Cycle 600TT Operational Assessments. EPRI, Palo Alto, CA: 2020. 3002018258.

RA-22-0106 Attachment Attachment Revised Technical Specifications

[7 pages follow this cover page]

Programs and Manuals 5.5 5.5 Programs and Manuals (continued)

HBRSEP 5.0-13 Amendment No. 235 5.5.9 Steam Generator (SG) Program (continued)

c.

Provisions for SG tube plugging criteria. Tubes found by inservice inspection to contain flaws with a depth equal to or exceeding the following criteria shall be plugged: 47% of the nominal tube wall thickness if the next inspection interval of that tube is 12 months, and a 2% reduction in the plugging criteria for each 12 month period until the next inspection of the tube.

The following alternate tube plugging criteria shall be applied as an alternative to the preceding criteria:

Tubes with service-induced flaws located greater than 18.11 inches below the top of the tubesheet do not require plugging. Tubes with service-induced flaws located in the portion of the tube from the top of the tubesheet to 18.11 inches below the top of the tubesheet shall be plugged upon detection.

d.

Provisions for SG tube inspections. Periodic SG tube inspections shall be performed. The number and portions of the tubes inspected and methods of inspection shall be performed with the objective of detecting flaws of any type (e.g., volumetric flaws, axial and circumferential cracks) that may be present along the length of the tube, from the tube-to-tubesheet weld at the tube inlet to the tube-to-tubesheet weld at the tube outlet and that may satisfy the applicable tube plugging criteria. The tube-to-tubesheet weld is not part of the tube. In addition to meeting the requirements of d.1, d.2, and d.3 below, the inspection scope, inspection methods, and inspection intervals shall be such as to ensure that SG tube integrity is maintained until the next SG inspection. A degradation assessment shall be performed to determine the type and location of flaws to which the tubes may be susceptible and, based on this assessment, to determine which inspection methods need to be employed and at what locations.

1.

Inspect 100% of the tubes in each SG during the first refueling outage following SG installation.

2.

After the first refueling outage following SG installation, inspect each SG at least every 48 effective full power months or at least every other refueling outage (whichever results in more frequent inspections). In addition, the minimum number of tubes inspected at each scheduled inspection shall be the number of tubes In all SGs divided by the number of SG inspection outages scheduled in each Inspection period as defined in a, b, and c below. If a degradation assessment indicates the potential for a type of degradation to occur at a location not previously Inspected with a technique capable of detecting this type of degradation at this location and that may satisfy

INSERT 1 except for any portions of the tube that are exempt from inspection by alternate repair criteria, INSERT 2 After the first refueling outage following SG installation, inspect 100% of the tubes in each SG at least every 54 effective full power months, which defines the inspection period. If none of the SG tubes have ever experienced cracking other than in regions that are exempt from inspection by alternate repair criteria and the SG inspection was performed with enhanced probes, the inspection period may be extended to 72 effective full power months. Additionally, the inspection period that began December 8, 2020 may be 72 effective full power months without prior performance of a SG inspection using enhanced probes. Enhanced probes have a capability to detect flaws of any type equivalent to or better than array probe technology. The enhanced probes shall be used from the tube-to-tubesheet weld at the tube inlet to the tube-to-tubesheet weld at the tube outlet except any portions of the tube that are exempt from inspection by alternate repair criteria. If there are regions where enhanced probes cannot be used, the tube inspection techniques shall be capable of detecting all forms of existing and potential degradation in that region.

INSERT 3 excluding any region that is exempt from inspection by alternate repair criteria INSERT 4

, but may be deferred to the following refueling outage if the 100% inspection of all SGs was performed with enhanced probes as described in paragraph d.2 INSERT 5

a. The scope of inspections performed on each SG;

b. The nondestructive examination techniques utilized for tubes with increased degradation susceptibility;

c. For each degradation mechanism found:

1. The nondestructive examination techniques utilized;

2. The location, orientation (if linear), measured size (if available), and voltage response for each indication. For tube wear at support structures less than 20 percent through-wall, only the total number of indications needs to be reported;

3.

A description of the condition monitoring assessment and results, including the margin to the tube integrity performance criteria and comparison with the margin predicted to exist at the inspection by the previous forward-looking tube integrity assessment;

4. The number of tubes plugged during the inspection outage.

d. An analysis summary of the tube integrity conditions predicted to exist at the next scheduled inspection (the forward-looking tube integrity assessment) relative to the applicable performance criteria, including the analysis methodology, inputs, and results;

e. The number and percentage of tubes plugged to date, and the effective plugging percentage in each SG;

f.

The results of any SG secondary side inspections;

g. The primary to secondary leakage rate observed in each SG (if it is not practical to assign the leakage to an individual SG, the entire primary to secondary leakage should be conservatively assumed to be from one SG) during the cycle preceding the inspection that is the subject of the report;

h. The calculated accident induced leakage rate from the portion of the tubes below 18.11 inches from the top of the tubesheet for the most limiting accident in the most limiting SG. In addition, if the calculated accident induced leakage rate from the most limiting accident is less than 1.87 times the maximum operational primary to secondary leakage rate, the report should describe how it was determined; and

RA-22-0106 Attachment Attachment Revised (Clean) Technical Specifications Pages

[5 pages follow this cover page]

Programs and Manuals 5.5 5.5 Programs and Manuals (continued)

(continued)

HBRSEP 5.0-12 Amendment No. XXX 5.5.9 Steam Generator (SG) Program An SG Program shall be established and implemented to ensure that SG tube integrity is maintained. In addition, the SG Program shall include the following:

a.

Provisions for condition monitoring assessments. Condition monitoring assessment means an evaluation of the as found condition of the tubing with respect to the performance criteria for structural integrity and accident induced leakage. The as found condition refers to the condition of the tubing during an SG inspection outage, as determined from the inservice inspection results or by other means, prior to the plugging of tubes.

Condition monitoring assessments shall be conducted during each outage during which the SG tubes are inspected or plugged to confirm that the performance criteria are being met.

b.

Performance criteria for SG tube integrity. SG tube integrity shall be maintained by meeting the performance criteria for tube structural integrity, accident induced leakage, and operational LEAKAGE.

1. Structural integrity performance criterion: All in-service SG tubes shall retain structural integrity over the full range of normal operating conditions (including startup, operation in the power range, hot standby, and cool down) and all anticipated transients included in the design specification, and design basis accidents. This includes retaining a safety factor of 3.0 against burst under normal steady state full power operation primary-to-secondary pressure differential and a safety factor of 1.4 against burst applied to the design basis accident primary-to-secondary pressure differentials. Apart from the above requirements, additional loading conditions associated with the design basis accidents, or combination of accidents in accordance with the design and licensing basis, shall also be evaluated to determine if the associated loads contribute significantly to burst or collapse. In the assessment of tube integrity, those loads that do significantly affect burst or collapse shall be determined and assessed in combination with the loads due to pressure with a safety factor of 1.2 on the combined primary loads and 1.0 on axial secondary loads.

2. Accident induced leakage performance criterion: The primary to secondary accident induced leakage rate for any design basis accident, other than a SG tube rupture, shall not exceed the leakage rate assumed in the accident analysis in terms of total leakage rate for all SGs and leakage rate for an individual SG. Leakage is not to exceed 150 gallons per day per SG.

3. The operational LEAKAGE performance criterion is specified in LCO 3.4.13, RCS Operational LEAKAGE.

Programs and Manuals 5.5 5.5 Programs and Manuals (continued)

HBRSEP 5.0-13 Amendment No. XXX 5.5.9 Steam Generator (SG) Program (continued)

c.

Provisions for SG tube plugging criteria. Tubes found by inservice inspection to contain flaws with a depth equal to or exceeding the following criteria shall be plugged: 47% of the nominal tube wall thickness if the next inspection interval of that tube is 12 months, and a 2% reduction in the plugging criteria for each 12 month period until the next inspection of the tube.

The following alternate tube plugging criteria shall be applied as an alternative to the preceding criteria:

Tubes with service-induced flaws located greater than 18.11 inches below the top of the tubesheet do not require plugging. Tubes with service-induced flaws located in the portion of the tube from the top of the tubesheet to 18.11 inches below the top of the tubesheet shall be plugged upon detection.

d.

Provisions for SG tube inspections. Periodic SG tube inspections shall be performed. The number and portions of the tubes inspected and methods of inspection shall be performed with the objective of detecting flaws of any type (e.g., volumetric flaws, axial and circumferential cracks) that may be present along the length of the tube, from the tube-to-tubesheet weld at the tube inlet to the tube-to-tubesheet weld at the tube outlet except for any portions of the tube that are exempt from inspection by alternate repair criteria, and that may satisfy the applicable tube plugging criteria. The tube-to-tubesheet weld is not part of the tube. In addition to meeting the requirements of d.1, d.2, and d.3 below, the inspection scope, inspection methods, and inspection intervals shall be such as to ensure that SG tube integrity is maintained until the next SG inspection. A degradation assessment shall be performed to determine the type and location of flaws to which the tubes may be susceptible and, based on this assessment, to determine which inspection methods need to be employed and at what locations.

1.

Inspect 100% of the tubes in each SG during the first refueling outage following SG installation.

2.

After the first refueling outage following SG installation, inspect 100% of the tubes in each SG at least every 54 effective full power months, which defines the inspection period. If none of the SG tubes have ever experienced cracking other than in regions that are exempt from inspection by alternate repair criteria and the SG inspection was performed with enhanced probes, the inspection period may be extended to 72 effective full power months. Additionally, the inspection

Programs and Manuals 5.5 5.5 Programs and Manuals (continued)

HBRSEP 5.0-14 Amendment No. XXX 5.5.9 Steam Generator (SG) Program (continued) period that began December 8, 2020 may be 72 effective full power months without prior performance of a SG inspection using enhanced probes. Enhanced probes have a capability to detect flaws of any type equivalent to or better than array probe technology. The enhanced probes shall be used from the tube-to-tubesheet weld at the tube inlet to the tube-to-tubesheet weld at the tube outlet except any portions of the tube that are exempt from inspection by alternate repair criteria. If there are regions where enhanced probes cannot be used, the tube inspection techniques shall be capable of detecting all forms of existing and potential degradation in that region.

3.

If crack indications are found in any portion of a SG tube excluding any region that is exempt from inspection by alternate repair criteria, then the next inspection for each affected and potentially affected SG for the degradation mechanism that caused the crack indication shall be at the next refueling outage, but may be deferred to the following refueling outage if the 100% inspection of all SGs was performed with enhanced probes as described in paragraph d.2. If definitive information, such as from examination of a pulled tube, diagnostic non-destructive testing, or engineering evaluation indicates that a crack-like indication is not associated with a crack(s), then the indication need not be treated as a crack.

e.

Provisions for monitoring operational primary to secondary LEAKAGE.

5.5.10 Secondary Water Chemistry Program This program provides controls for monitoring secondary water chemistry to inhibit SG tube degradation. The program shall include:

a.

Identification of critical parameters, their sampling frequency, sampling points, and control band limits;

Reporting Requirements 5.6 5.6 Reporting Requirements (continued)

(continued)

HBRSEP Unit No. 2 5.0-28 Amendment No. XXX 5.6.7 Tendon Surveillance Report

a.

Notification of a pending sample tendon test, along with detailed acceptance criteria, shall be submitted to the NRC at least two months prior to the actual test.

b.

A report containing the sample tendon test evaluation shall be submitted to the NRC within six months of conducting the test.

5.6.8 Steam Generator Tube Inspection Report A report shall be submitted within 180 days after the initial entry into MODE 4 following completion of an inspection performed in accordance with the Specification 5.5.9, Steam Generator (SG) Program. The report shall include:

a.

The scope of inspections performed on each SG;

b.

The nondestructive examination techniques utilized for tubes with increased degradation susceptibility;

c.

For each degradation mechanism found:

1. The nondestructive examination techniques utilized;

2. The location, orientation (if linear), measured size (if available), and voltage response for each indication. For tube wear at support structures less than 20 percent through-wall, only the total number of indications needs to be reported;

3. A description of the condition monitoring assessment and results, including the margin to the tube integrity performance criteria and comparison with the margin predicted to exist at the inspection by the previous forward-looking tube integrity assessment;

4. The number of tubes plugged during the inspection outage.

d.

An analysis summary of the tube integrity conditions predicted to exist at the next scheduled inspection (the forward-looking tube integrity assessment) relative to the applicable performance criteria, including the analysis methodology, inputs, and results;

e.

The number and percentage of tubes plugged to date, and the effective plugging percentage in each SG;

f.

The results of any SG secondary side inspections;

Reporting Requirements 5.6 5.0 ADMINISTRATIVE CONTROLS 5.6 Reporting Requirements (continued)

HBRSEP Unit No. 2 5.0-28a Amendment No. XXX 5.6.8 Steam Generator Tube Inspection Report (continued)

g.

The primary to secondary leakage rate observed in each SG (if it is not practical to assign the leakage to an individual SG, the entire primary to secondary leakage should be conservatively assumed to be from one SG) during the cycle preceding the inspection that is the subject of this report;

h.

The calculated accident induced leakage rate from the portion of the tubes below 18.11 inches from the top of the tubesheet for the most limiting accident in the most limiting SG. In addition, if the calculated accident induced leakage rate from the most limiting accident is less than 1.87 times the maximum operational primary to secondary leakage rate, the report should describe how it was determined; and

i.

The results of monitoring for tube axial displacement (slippage). If slippage is discovered, the implications of the discovery and corrective action shall be provided.

RA-22-0106 Reference 6 from the RO32 Condition Monitoring and Operational Assessment: Disposition of Foreign Object(s) Remaining in HB Robinson RSGs (Post-Secondary Side Inspection 2RFO

32)

[34 pages follow this cover page]

20004-026 (08/12/2020)

Page 1 of 34 Framatome Inc.

Engineering Information Record Document No.:

51 9321335 -

000 Disposition of Foreign Object(s) Remaining in HB Robinson RSGs (Post-Secondary Side Inspection 2RFO 32)

20004-026 (08/12/2020)

Document No.: 51-9321335-000 Disposition of Foreign Object(s) Remaining in HB Robinson RSGs (Post-Secondary Side Inspection 2RFO 32)

Page 2 Safety Related?

YES NO Does this document establish design or technical requirements?

YES NO Does this document contain assumptions requiring verification?

YES NO Does this document contain Customer Required Format?

YES NO Signature Block Name and Title/Discipline Signature P/LP, R/LR, M, A-CRF, A Date Pages/Sections Prepared/Reviewed/

Approved or Comments John Burgess Advisory Engr LP All Eddie Grubbs Principal Engr LR All Wayne Belden Manager A

All Note: P/LP designates Preparer (P), Lead Preparer (LP)

M designates Mentor (M)

R/LR designates Reviewer (R), Lead Reviewer (LR)

A-CRF designates Project Manager Approver of Customer Required Format (A-CRF)

A designates Approver/RTM - Verification of Reviewer Independence Project Manager Approval of Customer References (N/A if not applicable)

Name (printed or typed)

Title (printed or typed)

Signature Date N/A

20004-026 (08/12/2020)

Document No.: 51-9321335-000 Disposition of Foreign Object(s) Remaining in HB Robinson RSGs (Post-Secondary Side Inspection 2RFO 32)

Page 3 Record of Revision Revision No.

Pages/Sections/

Paragraphs Changed Brief Description / Change Authorization 000 All Initial release

Document No.: 51-9321335-000 Disposition of Foreign Object(s) Remaining in HB Robinson RSGs (Post-Secondary Side Inspection 2RFO 32)

Page 4 Table of Contents Page SIGNATURE BLOCK............................................................................................................................. 2 RECORD OF REVISION....................................................................................................................... 3 LIST OF TABLES.................................................................................................................................. 5 LIST OF FIGURES................................................................................................................................ 6 1.0 PURPOSE................................................................................................................................. 7

2.0 BACKGROUND

......................................................................................................................... 7 3.0 ASSUMPTIONS......................................................................................................................... 7 3.1 Assumptions Requiring Verification................................................................................ 7 3.2 Assumptions That Do Not Require Verification............................................................... 7 4.0 FOREIGN OBJECT SCREENING CRITERIA............................................................................ 7 5.0 DISPOSITION OF FOREIGN OBJECTS REMAINING IN STEAM GENERATORS.................. 10 5.1 Evaluation of Foreign Objects in SGA........................................................................... 10 5.1.1 Category 1 Foreign Objects............................................................................ 10 5.1.2 Category 2 Foreign Objects............................................................................ 10 5.1.3 Category 3 Foreign Objects............................................................................ 10 5.1.4 Evaluation of Potential Wear from Objects..................................................... 11 5.1.5 Foreign Material from the Water Lance Strainer (FOTS Item 21).................... 11 5.1.6 Eddy Current PLP Locations.......................................................................... 11 5.2 Evaluation of Foreign Objects in SGB........................................................................... 20 5.2.1 Category 1 Foreign Objects............................................................................ 20 5.2.2 Category 2 Foreign Objects............................................................................ 20 5.2.3 Category 3 Foreign Objects............................................................................ 20 5.2.4 Evaluation of Potential Wear from Objects..................................................... 21 5.2.5 Foreign Material from the Water Lance Strainer (FOTS Item 29).................... 21 5.2.6 Eddy Current PLP Locations.......................................................................... 21 5.3 Evaluation of Foreign Objects in SGC........................................................................... 27 5.3.1 Category 1 Foreign Objects............................................................................ 27 5.3.2 Category 2 Foreign Objects............................................................................ 27 5.3.3 Category 3 Foreign Objects............................................................................ 27 5.3.4 Evaluation of Potential Wear from Objects..................................................... 28 5.3.5 Foreign Material from the Water Lance Strainer (FOTS Item 29).................... 28 5.3.6 Eddy Current PLP Locations (FOTS Item 30)................................................. 28

6.0 CONCLUSION

S....................................................................................................................... 34 7.0 COLD STORAGE FILE(S)........................................................................................................ 34

8.0 REFERENCES

......................................................................................................................... 34

Document No.: 51-9321335-000 Disposition of Foreign Object(s) Remaining in HB Robinson RSGs (Post-Secondary Side Inspection 2RFO 32)

Page 5 List of Tables Page Table 4-1: Foreign Object Classification and Screening Criteria........................................................... 9 Table 5-1: SGA Category 3 Foreign Objects....................................................................................... 11 Table 5-2: SGA Summary of PLP Calls.............................................................................................. 11 Table 5-3: SGB Category 1 Foreign Objects....................................................................................... 20 Table 5-4: SGB Category 3 Foreign Objects....................................................................................... 21 Table 5-5: SGC Category 1 Foreign Objects....................................................................................... 27 Table 5-6: SGC Category 3 Foreign Objects....................................................................................... 28 Table 7-1: Cold Storage File(s)........................................................................................................... 34

Document No.: 51-9321335-000 Disposition of Foreign Object(s) Remaining in HB Robinson RSGs (Post-Secondary Side Inspection 2RFO 32)

Page 6 List of Figures Page Figure 5-1: SGA FOTS Item 14 (Sludge Rock).................................................................................. 12 Figure 5-2: SGA FOTS Item 16 (Small Bristle).................................................................................. 13 Figure 5-3: SGA FOTS Item 17 (Small Wire)..................................................................................... 13 Figure 5-4: SGA Water Lance Strainer Contents, Flexitallic Gasket Pieces.................................. 14 Figure 5-5: SGA Water Lance Strainer Contents, Metallic Parts..................................................... 15 Figure 5-6: SGA Water Lance Strainer Contents, Sludge Scale..................................................... 16 Figure 5-7: SGA PLP - FOTS Item 22 (Tube Scale at Affected Tube Locations)............................ 17 Figure 5-8: SGA PLP - FOTS Item 23 (Tube Scale at Affected Tube Locations)............................ 18 Figure 5-9: SGA PLP - FOTS Item 25 (Tube Scale at Affected Tube Locations)............................ 19 Figure 5-10: SGB FOTS Item 25 (Gasket Material)........................................................................... 22 Figure 5-11: SGB FOTS Item 26 (Sludge Rock)................................................................................ 22 Figure 5-12: SGB FOTS Item 27 (Sludge Rock)................................................................................ 23 Figure 5-13: SGB FOTS Item 28 (Sludge Rock)................................................................................ 23 Figure 5-14: SGB Water Lance Strainer Contents, Flexitallic Gasket Pieces................................ 24 Figure 5-15: SGB Water Lance Strainer Contents, Metallic Parts................................................... 25 Figure 5-16: SGB Water Lance Strainer Contents, Sludge Scale................................................... 26 Figure 5-17(A): SGC FOTS Item 13 (Machine Turning) - As Left at 2RFO32.................................. 29 Figure 5-18: SGC FOTS Item 27 (Flexitallic Gasket)........................................................................ 31 Figure 5-19: SGC FOTS Item 28 (Rectangular Object).................................................................... 31 Figure 5-20: SGC Water Lance Strainer Contents, Flexitallic Gasket Pieces................................ 32 Figure 5-21: SGC Water Lance Strainer Contents, Metallic Parts.................................................. 32 Figure 5-22: SGC Water Lance Strainer Contents, Misc. Parts....................................................... 33

Document No.: 51-9321335-000 Disposition of Foreign Object(s) Remaining in HB Robinson RSGs (Post-Secondary Side Inspection 2RFO 32)

Page 7 1.0 PURPOSE The purpose of this document is to provide an engineering evaluation of the foreign objects (FOs) that remain in the secondary side of the RSGs at HB Robinson (Unit 2). These FOs were not retrieved from the tube bundle during the Foreign Object Search and Retrieval (FOSAR) evolution of 2RFO 32 and thus require disposition.

This assessment is limited to objects being left in service for a maximum of three (3) operational cycles or a total of six (6) Effective Full Power Years (EFPY) and thus, allows for a double skip inspection.

2.0 BACKGROUND

Periodic inspections of power plant hardware are performed to look for degradation that could be detrimental to the structural integrity of the component. One of the most highly inspected components is the steam generators.

Typical steam generator inspections include Eddy Current (EC) examination of the tubes and visual inspection of the secondary side. The EC inspection can detect tube wall degradation but can also identify Potential Loose Parts (PLP) that may be in contact with or very close to the tube. The secondary side visual inspection uses remotely operated tooling/cameras to look for degradation as well as potential foreign objects that may have entered the generator. The foreign objects have the potential to wear against a tube which could result in a reduction of tube wall thickness that can lead to a violation of the tube wall and primary-to-secondary leakage.

In recent years industry representatives acting though the Electric Power Research Institute (EPRI) have developed a comprehensive steam generator management program for addressing the care and maintenance of power plant steam generators. As part of the EPRI program, several reports have been published pertaining to foreign objects. One of the program reports deals with the prioritization of foreign objects in a square pitch steam generator, Reference 2, like those at the Robinson plant. The details and recommendations from the EPRI reports are used to develop the screening criteria for HB Robinson steam generators, which are documented in Reference

1.

3.0 ASSUMPTIONS 3.1 Assumptions Requiring Verification There are no assumption(s) requiring verification considered in this report.

3.2 Assumptions That Do Not Require Verification There are no general assumptions used in this assessment.

4.0 FOREIGN OBJECT SCREENING CRITERIA The screening criteria for foreign objects enable a method to quickly assess/prioritize objects that may be found in the secondary side of the HB Robinson steam generators. Based on the location in the tube bundle and specifics of the foreign object identified during the inspection, the criteria can be used to determine if the object is acceptable to leave in place or if it should be removed. Items screened for removal may be evaluated in more detail to see if they qualify for potential justification for short term operation or they may be left in place provided appropriate preventative plugging is performed.

The screening criteria for the FOs in the HB Robinson steam generators is developed in Reference 1. Due to the historical concentration of objects at the secondary face of the tubesheet and the relatively large variations in critical thermal hydraulic parameters (flow and density) throughout the steam generators required for the assessment of foreign objects, the screening criteria are limited to objects located on the top of tubesheet. The screening criteria developed therein is in part based on the methodology outlined in EPRI Steam Generator Management Program (SGMP) report, Foreign Object Prioritization Strategy for Square Pitch Steam Generators, Reference 2. The screening criteria also considered a review of historical FOs discovered in the HB Robinson SG tube bundle and the application of tube wear calculations documented in Reference 3.

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Page 8 EPRI groups foreign objects by the following three (3) categories:

Category 1: Objects that are unacceptable for in-service operation and therefore must be removed or the potentially affected tubes plugged (and possibly stabilized). If left in service, these objects can cause tube degradation (wear) in excess of 40% TW before the next scheduled inspection.

Depending on the inspection interval, this could include one, two or maybe three operational cycles.

Category 2: Objects that are acceptable for in-service operation through the next inspection but must be reassessed at that time. These objects can cause tube degradation but the damage is not expected to exceed of 40% TW through the next scheduled inspection. Depending on the inspection interval, this could include one, two or maybe three operational cycles (up to 6 EFPY).

Category 3: Objects that are acceptable for extended in-service operation and are not expected to cause tube degradation even when exposed to multiple operational cycles (e.g., >> 6 EFPY).

The acceptance criteria used for foreign object screening are simply that any identified foreign object that is left in-service is not expected to result in degradation to the tube(s) that could exceed the allowable degradation limits. The tube wear calculations are based on a conservative set of design inputs that are intended to bound the parameters that are most relevant to tube wear created by foreign objects. These include flow rates, wear rates, fixity, etc.

Table 4-1 provides a summary of screening criteria for the foreign objects left in the SG tube bundle. Objects recommended for removal are identified for both peripheral and inner bundle tube locations. The table is used to quickly assess if an object found during SSI is acceptable to remain in service or should be removed into short term Category 2 (up to 6 EFPY) and long-term Category 3 items (>> 6 EFPY). If an object is recommended for removal, an optional object-specific assessment can be prepared by applying the Mathcad worksheets documented in Reference 3 or the affected tube(s) can be preventatively plugged.

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Page 9 Table 4-1: Foreign Object Classification and Screening Criteria (per Table 6-3 of Reference 1)

Object Type Periphery Inner Bundle Category 1 (remove)

Category 1 (remove)

Category 2 (6 EFPY)

Category 3

(>> 6 EFPY) weld remnants (splatter, slag) all all N/A N/A nails, bolts, screws all all N/A N/A any object with associated tube wear all all N/A N/A wires (semi-stiff) all

> 1/8 diameter by 2.25 long

< 1/8 diameter by 2.25 long

< 1/8 diameter by 1.5 long gasket metal winding (semi-stiff) all

> 1.75 long

< 1.75 long

< 1 long bristle (stiff) all

> 1/32 diameter by 2.0 long

< 1/32 diameter by 2.0 long

< 1/32 diameter by 2.0 long circular metal object (stiff rods) all

> 1/8 diameter by 2.25 long

< 1/8 diameter by 2.25 long

< 1/8 diameter by 1.5 long rectangular metal object (stiff bars) all

> 1/4 x 1/4 by 1 long

< 1/4 x 1/4 by 1 long

< 1/4 x 1/4 by 3/4 long spherical metal object all

> 0.35 diameter

< 0.35 diameter if not lodged against a tube(s)

N/A sludge products (rocks, flakes, collars, scale)

With embedded metallic object NA Without embedded metallic object Notes:

Periphery - SG annulus and outer 5 tubes in high flow region Inner Bundle - tubes inside of periphery band where the flow is less Category 1 - objects should be removed Category 2 - acceptable for a service life of 6 EFPY Category 3 - acceptable for an extended service life >> 6 EFPY Notes for Table 4-1;

1) Objects recommended for removal may be evaluated on a case-by-case basis to determine if they are acceptable to remain in service. Objects found in the periphery may use the acceptance criteria for the inner bundle objects since the inner bundle values (criteria) are based on a conservative flow rate that exceeds that identified for the periphery of the steam generator.

2) The limiting object sizes for the inner bundle are consistent with those defined in EPRI Table 5-1 of Reference 2 and also those defined by Westinghouse in their screening criteria for the previous HBR outages.

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Page 10 5.0 DISPOSITION OF FOREIGN OBJECTS REMAINING IN STEAM GENERATORS 5.1 Evaluation of Foreign Objects in SGA 5.1.1 Category 1 Foreign Objects There are no category 1 foreign objects in SGA.

5.1.2 Category 2 Foreign Objects There are no category 2 foreign objects in SGA.

5.1.3 Category 3 Foreign Objects Table 5-1 lists the 2R32 foreign objects identified as Category 3 items per the screening criteria of Reference 1 and their final disposition. A disposition / evaluation of each object left in the SG is provided below.

FOTS Item 14 FOTS item 14 is a historical sludge rock located in the periphery of the tube bundle between tube locations R38C26 and R38C25. It has not moved from this location since previous inspections. Based upon its location, this FO would be classified as a category 1 object. However, the FO is not embedded with metallic type objects.

Therefore, this FO is considered to be a category 3 object. The wear life of the adjacent tubes is >> 6 EFPY.

FOTS Item 16 FOTS item 16 is a small bristle located in the inner bundle that is fixed in the sludge pile. Its size is smaller than 1/32-inch diameter x 0.30-inch length and thus is classified a category 3 object. Based upon the fixity of this type object in the sludge pile, its size and location in the inner bundle, the adjacent tubes are not predicted to experience wear from this FO. The wear life of the adjacent tubes is >> 6 EFPY.

FOTS Item 17 FOTS item 17 is a small wire located in the inner bundle that is fixed in the sludge pile. Its size is smaller than 1/16-inch diameter x 0.75-inch length and thus is classified a category 3 object. Based upon the fixity of this type object in the sludge pile, its size and location in the inner bundle, the adjacent tubes are not predicted to experience wear from this FO. The wear life of the adjacent tubes is >> 6 EFPY.

FOTS Item 20 FOTS item 20 is hard collar / scale that was most likely removed from the center of the tube bundle during sludge lancing and was then washed to the periphery of the tube bundle. This FO broke into two pieces when it was initially retrieved. SSI attempted to retrieve the remnant of this FO but could not locate it. Based upon discussions with SSI and their review of the original video of this object, it was concluded the size of the remnant left in the SG is less than 1/8 x 1/4. Therefore, this object can easily move between tube gaps (0.359) and not get pinched between two tubes to cause tube wear. It will most likely migrate to a low flow area of the tube bundle and become fractured into to smaller pieces. Based upon the location this object was found, the object would be classified as a category 1 object. However, the FO is not embedded with metallic type objects.

Therefore, this FO is considered to be a category 3 object. The adjacent tubes are not predicted to experience wear from this FO. The wear life of the adjacent tubes is >> 6 EFPY.

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Page 11 Table 5-1: SGA Category 3 Foreign Objects FOTS Item Description (L x W x H)

(inches)

Location Row-Col.

Removed (Yes/No/Part Not Found) 2R32 Assessment

1. 14 (Figure 5-1)

Sludge Rock (0.5x0.5x0.5) 38-26 TSH 38-25 TSH No Acceptable in-place (Per Reference 1)

1. 16 (Figure 5-2)

Small Bristle

(<1/32 dia. x 0.3 length) 12-40 TSH 11-40 TSH No Acceptable in-place (Per Reference 1)

1. 17 (Figure 5-3)

Wire

(< 1/16 dia. X 0.75 length) 1-46 TSH 1-45 TSH No Acceptable in-place (Per Reference 1)

1. 18 Hard Deposit / Collar 45-42 TSH 45-43 TSH Yes N/A

1. 19 Hard Deposit / Collar 44-39 TSH 44-40 TSH Yes N/A

1. 20 Hard Deposit / Collar 45-52 TSC Yes/No Acceptable in-place (Per Reference 1) 5.1.4 Evaluation of Potential Wear from Objects All Category 3 objects listed in Table 5-1 have been evaluated against the assessments performed in Reference 1 and not expected to cause any significant tube wear after 6 EFPY.

5.1.5 Foreign Material from the Water Lance Strainer (FOTS Item 21)

As a result of the water-lancing performed on SGA, three (3) different types of foreign material were retrieved from the strainer. They were flexitallic gasket pieces, metallic parts, and sludge scale. An overview of all the foreign material retrieved is provided in Figure 5-4 through Figure 5-6.

5.1.6 Eddy Current PLP Locations Eddy current inspections performed during outage 2R32 detected the possible presence of foreign objects in steam generator SGA as listed in Table 5-2. No tube degradation was associated with these any of these PLP locations.

Table 5-2: SGA Summary of PLP Calls Location Row-Col.

2R32 ECT Call FOSAR Results R3-C18 FBH R4-C18 FBH R5-C17 FBH FOTS Item 22 PLP per Array data; no tube wear.

Tube scale found at the affected tube locations. This material easily broke into pieces using the FOSAR probe. These scale pieces were left in the SG. No other foreign material found in surrounding tubes.

Regions where tube scale was found were bounded by Array and no wear was detected.

R17-C14 FBH R18-C14 FBH FOTS Item 23 PLP per Array data; no tube wear.

Tube scale found at the affected tube locations. This material easily broke into pieces using the FOSAR probe. These scale pieces were left in the SG. No other foreign material found in surrounding tubes.

Regions where tube scale was found were bounded by Array and no wear was detected.

R17-C5 FBH R17-C6 FBH R16-C6 FBH FOTS Item 25 PLP per Array data; no tube wear.

Tube scale found at the affected tube locations. This material easily broke into pieces using the FOSAR probe. These scale pieces were left in the SG. No other foreign material found in surrounding tubes.

Regions where tube scale was found were bounded by Array and no wear was detected.

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Page 12 These locations were visually inspected and only tube scale was found (Figure 5-7 through Figure 5-9). This material easily broke into pieces using the FOSAR probe and remains in the steam generator. The secondary side inspection revealed no evidence of wear on any of the affected alloy-600 tubes where this material was found. In addition, the regions where tube scale was found were bounded by Array and no wear was detected. In summary, there is no evidence of damage to any of these identified tubes or the surrounding tubes and the broken tube scale pieces remaining in the SG are not a threat to tube integrity.

Conclusion The broken tube scale pieces remaining in SGA in the vicinity of the PLP locations shown in Table 5-2 do not present any integrity concerns for the pressure boundary of the tubes. No future action required for these FOTS items.

Figure 5-1: SGA FOTS Item 14 (Sludge Rock)

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Page 13 Figure 5-2: SGA FOTS Item 16 (Small Bristle)

Figure 5-3: SGA FOTS Item 17 (Small Wire)

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Page 14 Figure 5-4: SGA Water Lance Strainer Contents, Flexitallic Gasket Pieces

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Page 15 Figure 5-5: SGA Water Lance Strainer Contents, Metallic Parts

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Page 16 Figure 5-6: SGA Water Lance Strainer Contents, Sludge Scale

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Page 17 Figure 5-7: SGA PLP - FOTS Item 22 (Tube Scale at Affected Tube Locations)

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Page 18 Figure 5-8: SGA PLP - FOTS Item 23 (Tube Scale at Affected Tube Locations)

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Page 19 Figure 5-9: SGA PLP - FOTS Item 25 (Tube Scale at Affected Tube Locations)

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Page 20 5.2 Evaluation of Foreign Objects in SGB 5.2.1 Category 1 Foreign Objects As shown in Table 5-3, only one Category 1 foreign object was identified in SGB.

FOTS item 25 is a flexitallic gasket piece that was located in the periphery of the tube bundle between tube locations R35C74, R34C74, R34C73, R33C73, and R34C72 TSH. This foreign object was removed from the tube bundle.

Table 5-3: SGB Category 1 Foreign Objects FOTS Item #

Description (L x W x H)

(inches)

Location Row-Col.

Removed (Yes/No/Part Not Found) 2R32 Assessment

1. 25 (Figure 5-10)

Gasket (6.0x0.12x0.12) 35-74 TSH 34-74 TSH 34-73 TSH 34-72 TSH 33-73 TSH Yes Object was removed from tube bundle.

5.2.2 Category 2 Foreign Objects There are no category 2 foreign objects in SGB.

5.2.3 Category 3 Foreign Objects Table 5-4 lists the 2R32 foreign objects identified as Category 3 items per the screening criteria of Reference 1 and their final disposition. A disposition / evaluation of each object left in the SG is provided below.

FOTS Item 26 FOTS item 26 is a sludge rock located in the periphery of the tube bundle between tube locations R43C49 and R43C48 TSH. The sludge rock is entangled with hard scale / collar. Based upon its location in the periphery of the tube bundle, this FO would be classified as a category 1 object. However, the FO is not embedded with metallic type objects. Therefore, this FO is considered to be a category 3 object. The wear life of the adjacent tubes is >> 6 EFPY.

FOTS Item 27 FOTS item 27 is a sludge rock located in the periphery of the tube bundle between tube locations R41C47 and R41C46 TSC. Based upon its location in the periphery of the tube bundle, this FO would be classified as a category 1 object. However, the FO is not embedded with metallic type objects. Therefore, this FO is considered to be a category 3 object. The wear life of the adjacent tubes is >> 6 EFPY.

FOTS Item 28 FOTS item 28 is a sludge rock located 6 tubes in from the periphery of the tube bundle between tube locations R36C64 and R36C63 TSC. Based upon its location in the inner tube bundle and its lack of metallic embedments, this FO is a category 3 object. The wear life of the adjacent tubes is >> 6 EFPY.

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Page 21 Table 5-4: SGB Category 3 Foreign Objects FOTS Item #

Description (L x W x H)

(inches)

Location Row-Col.

Removed (Yes/No/Part Not Found) 2R32 Assessment

1. 26 (Figure 5-11)

Sludge Rock (0.35x0.25x0.75) 43-49 TSH 43-48 TSH No Acceptable in-place (Per Reference 1)

1. 27 (Figure 5-12)

Sludge Rock (0.75x0.35x0.35) 41-47 TSC 41-46 TSC No Acceptable in-place (Per Reference 1)

1. 28 (Figure 5-13)

Sludge Rock (1.0x0.10x0.25) 36-63 TSC 36-64 TSC No Acceptable in-place (Per Reference 1) 5.2.4 Evaluation of Potential Wear from Objects All Category 3 objects listed in Table 5-4 have been evaluated against the assessments performed in Reference 1 and not expected to cause any significant tube wear after 6 EFPY.

5.2.5 Foreign Material from the Water Lance Strainer (FOTS Item 29)

As a result of the water-lancing performed on SGB, three (3) different types of foreign material were retrieved from the strainer. They were flexitallic gasket pieces, metallic parts, and sludge scale. An overview of all the foreign material retrieved is provided in Figure 5-14 through Figure 5-16.

5.2.6 Eddy Current PLP Locations None

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Page 22 Figure 5-10: SGB FOTS Item 25 (Gasket Material)

Figure 5-11: SGB FOTS Item 26 (Sludge Rock)

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Page 23 Figure 5-12: SGB FOTS Item 27 (Sludge Rock)

Figure 5-13: SGB FOTS Item 28 (Sludge Rock)

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Page 24 Figure 5-14: SGB Water Lance Strainer Contents, Flexitallic Gasket Pieces

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Page 25 Figure 5-15: SGB Water Lance Strainer Contents, Metallic Parts

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Page 26 Figure 5-16: SGB Water Lance Strainer Contents, Sludge Scale

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Page 27 5.3 Evaluation of Foreign Objects in SGC 5.3.1 Category 1 Foreign Objects As shown in Table 5-5, only one Category 1 foreign object was identified in SGC.

FOTS item 13 is a metal machine turning located in the periphery of the tube bundle on the FBH between tube locations R29C12, R29C13, R30C13, and R31C13 which, have been plugged and stabilized. This legacy foreign object has not moved from these tube locations since it was last inspected (2RFO30). A comparison of the pics obtained during this inspection and the previous inspection shows that the FO has however re-oriented itself between the same group of tubes as shown with Figure 5-17(A) and Figure 5-17(B). Note the new rectangular object laying on top of this item is tube scale, and not an additional FO. The objects was not removed from the tube bundle.

Table 5-5: SGC Category 1 Foreign Objects FOTS Item Description (L x W x H)

(inches)

Location Row-Col.

Removed (Yes/No/Part Not Found) 2R32 Assessment

1. 13 Figure 5-17 Machine Turning 29-12 FBH 29-13 FBH 30-13 FBH 31-13 FBH No Acceptable as is.

5.3.2 Category 2 Foreign Objects There are no category 2 foreign objects in SGC.

5.3.3 Category 3 Foreign Objects Table 5-6 lists the 2R32 foreign objects identified as Category 3 items per the screening criteria of Reference 1 and their final disposition. A disposition / evaluation of each object left in the SG is provided below.

FOTSG Item 25 FOTS item 25 is a sludge rock that was not found during SSI / FOSAR. A review of historical picture of this object from 2R30 show that this sludge rock was not embedded with metallic objects. Therefore, this FO is a category 3 object. This legacy object was apparently displaced from these tube locations, out of the tube bundle and captured by the sludge lance strainers. If the sludge rock was not removed during sludge lancing and became lodge next to a group of tubes, it would not have the potential to create significant tube wear, regardless of its tube bundle location. The wear life of the tubes would be >> 6 EFPY.

FOTS Item 28 FOTS item 28 is a rectangular metal object located in the inner bundle that is fixed at one end to the TSC (R2C51) and free at it opposite end, which is adjacent to tube location R2C50. SSI / FOSAR pulled on the free end of the FO with ~ 10 lbs of force and the FO would not dislodge from the TS. The size of the object is; 0.75 length x 0.12 width x ~0.05 thickness. The thickness dimension is approximate because this dimension could not be accurately measured.

Per Table 6-3 of Reference 1 FOTS Item 28 is a Category 3 object (wear life of tube is >> 6 EFPY). However, a conservative application of this criteria would dictate a Category 2 object (wear life of tube is 6 EFPY), which is observed in this evaluation.

To demonstrate the tubes adjacent to Item 28 have a wear life >> 6 EFPY, the following analysis is provided. The affected tubes are located near the center of the tube bundle where the cross-flow velocities are small (< 2 ft/sec per Figure 4-2 of Reference 1). The screening criteria developed in Reference 1 considers a cross flow velocity of 10 ft/sec. Additionally, as stated in Section 6.2 of Reference 1, conservatism exist with the predictions for the wear life of tubes when their dynamic interaction is with rectangular objects. To add additional rigor to this

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Page 28 assertion, a tube / foreign object interaction wear analysis is performed considering a conservative 10 ft/sec cross flow velocity and the dimensions of FOTS Item 28. Using a very conservative wear coefficient (71.8 psi-1), the results of the analysis demonstrate the wear life of the tube is 315 years (Computer run: FOTS Item 28.xmcd, See Table 7-1). Therefore, FOTS Item 28 is classified as a Category 3 object.

The region for FOTS Item 28 was bounded by Array and no wear was detected in any of the affected / bounding tubes.

Table 5-6: SGC Category 3 Foreign Objects FOTS Item #

Description (L x W x H)

(inches)

Location Row-Col.

Removed (Yes/No/Part Not Found) 2R32 Assessment

1. 25 (no Fig)

Sludge Rock 7-46 TSH 8-46 TSH Not Found None required. Sludge lancing displaced / removed rock from tube bundle.

1. 27 (Figure 5-18)

Gasket (1.0x0.2x0.02) 38-49 TSH 38-50 TSH 39-49 TSH 39-50 TSH Yes None required

1. 28 (Figure 5-19)

Rectangular Object (0.75x0.12x0.05) 2-50 TSC 2-51 TSC No Acceptable in-place (Per Reference 1 and specific wear analysis for this object, Computer Run: FOTS Item 28.xmcd) 5.3.4 Evaluation of Potential Wear from Objects The tubes adjacent to the Category 1 object listed in Table 5-5 were plugged and stabilized during 2RFO30. The FO has not moved from this location since it was last inspected. Therefore, this object is not expected to cause any significant tube wear after 6 EFPY. All Category 3 objects listed in Table 5-6 have been evaluated against the assessments performed in Reference 1 and not expected to cause any significant tube wear after 6 EFPY.

5.3.5 Foreign Material from the Water Lance Strainer (FOTS Item 29)

As a result of the water-lancing performed on SGC, three (3) different types of foreign material were retrieved from the strainer. They were flexitallic gasket pieces, metallic parts, and miscellaneous parts. An overview of all the foreign material retrieved is provided in Figure 5-20 through Figure 5-22.

5.3.6 Eddy Current PLP Locations (FOTS Item 30)

Eddy current inspections performed during outage 2R32 detected the possible presence of a foreign object in steam generator SGC at location R29-C45 TSC. This is an historical ECT PLP that was first detected during outage MC29. A comparative review of the ECT data from 2R30 and 2R32 shows that the Array signal has not changed. The region was bounded by Array and no wear was detected in any of the tubes and no PLPs were detected in any of the bounding tubes.

Conclusion The historical ECT PLP at location R29-C45 TSC does not present any integrity concerns for the pressure boundary of the affected / bounding tubes. Eddy current inspection for the next ISI outage is recommended for this PLP location to verify conditions have not changed.

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Page 29 Figure 5-17(A): SGC FOTS Item 13 (Machine Turning) - As Left at 2RFO32 Note the new rectangular object laying on top of this item 13 is tube scale, and not an additional FO.

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Page 30 Figure 5-17(B): SGC FOTS Item 13 (Machine Turning) - As Found at 2RFO30

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Page 31 Figure 5-18: SGC FOTS Item 27 (Flexitallic Gasket)

Figure 5-19: SGC FOTS Item 28 (Rectangular Object)

Note for Figure 5-19, these tubes are labeled incorrectly. The correct tube labels are R2C50 and R2C51 (left to right).

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Page 32 Figure 5-20: SGC Water Lance Strainer Contents, Flexitallic Gasket Pieces Figure 5-21: SGC Water Lance Strainer Contents, Metallic Parts

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Page 33 Figure 5-22: SGC Water Lance Strainer Contents, Misc. Parts

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Page 34

6.0 CONCLUSION

S Based on the wear evaluations, an allowable degradation limit (wear) of 40% through-wall (TW) is not expected to be challenged by these metallic objects in the tube bundle for 6 EFPYs of operation. These objects can be left in the SGs without plugging or stabilizing affected and bounding tubes at 2R32.

Sludge lancing removed 185.5 lbs (total) of material from the SGs. The breakdown of this weight per SG is; SG-A: 39 lbs SG-B: 33 lbs SG-C: 38.5 lbs Tank 75.0 lbs 7.0 COLD STORAGE FILE(S)

The Mathcad worksheet files listed in Table 7-1 are uploaded to the COLD storage file repository in folder:

\\\\cold\\General-Access\\51\\51-9321335-000\\official.

Table 7-1: Cold Storage File(s)

File Name Date Time (EST)

Description FOTS Item 28.xmcd 11/21/20 23:09:34 Tube - FO interaction wear analysis of FOTS Item 28 (SGC)

8.0 REFERENCES

1.

Framatome Inc. Document 51-9209100-003, HB Robinson SG Foreign Object Screening Criteria

2.

EPRI Document 1019039, Steam Generator Management Program: Foreign Object Prioritization Strategy for Square Pitch Steam Generators, May 2009.

3.

Framatome Inc. Document 51-9207539-001, Method to Determine Tube Wear Created by Foreign Objects in Secondary Side of RSGs

RA-22-0106 Affidavit of Westinghouse

[3 pages follow this cover page]

Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-22-016 Page 1 of 3 Commonwealth of Pennsylvania:

County of Butler:

(1)

I, Zachary Harper, Manager, Licensing Engineering, have been specifically delegated and authorized to apply for withholding and execute this Affidavit on behalf of Westinghouse Electric Company LLC (Westinghouse).

(2)

I am requesting the proprietary portions of CPL-NRCD-RF-LR-000001 P-Attachment, ant, Unit 2 - Responses to NRC Request for Additional Information from the Application to Adopt Technical Specifications Task Force Frequencies for Steam Generator Tube under 10 CFR 2.390.

(3)

I have personal knowledge of the criteria and procedures utilized by Westinghouse in designating information as a trade secret, privileged, or as confidential commercial or financial information.

(4)

Pursuant to 10 CFR 2.390, the following is furnished for consideration by the Commission in determining whether the information sought to be withheld from public disclosure should be withheld.

(i)

The information sought to be withheld from public disclosure is owned and has been held in confidence by Westinghouse and is not customarily disclosed to the public.

(ii)

The information sought to be withheld is being transmitted to the Commission in

, is not available in public sources.

(iii)

Westinghouse notes that a showing of substantial harm is no longer an applicable criterion for analyzing whether a document should be withheld from public disclosure. Nevertheless, public disclosure of this proprietary information is likely to cause substantial harm to the competitive position of Westinghouse because it would enhance the ability of competitors to provide similar technical evaluation justifications and licensing defense services for commercial power reactors without commensurate expenses. Also, public disclosure of the information would enable

Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-22-016 Page 2 of 3 others to use the information to meet NRC requirements for licensing documentation without purchasing the right to use the information.

(5)

Westinghouse has policies in place to identify proprietary information. Under that system, information is held in confidence if it falls in one or more of several types, the release of which might result in the loss of an existing or potential competitive advantage, as follows:

(a)

The information reveals the distinguishing aspects of a process (or component, structure, tool, method, etc.) where prevention of its use by any of Westinghouse's competitors without license from Westinghouse constitutes a competitive economic advantage over other companies.

(b)

It consists of supporting data, including test data, relative to a process (or component, structure, tool, method, etc.), the application of which data secures a competitive economic advantage (e.g., by optimization or improved marketability).

(c)

Its use by a competitor would reduce his expenditure of resources or improve his competitive position in the design, manufacture, shipment, installation, assurance of quality, or licensing a similar product.

(d)

It reveals cost or price information, production capacities, budget levels, or commercial strategies of Westinghouse, its customers or suppliers.

(e)

It reveals aspects of past, present, or future Westinghouse or customer funded development plans and programs of potential commercial value to Westinghouse.

(f)

It contains patentable ideas, for which patent protection may be desirable.

(6)

The attached documents are bracketed and marked to indicate the bases for withholding. The justification for withholding is indicated in both versions by means of lower-case letters (a) through (f) located as a superscript immediately following the brackets enclosing each item of information being identified as proprietary or in the margin opposite such information. These lower-case letters refer to the types of information Westinghouse customarily holds in confidence identified in Sections (5)(a) through (f) of this Affidavit.

Westinghouse Non-Proprietary Class 3 AFFIDAVIT CAW-22-016 Page 3 of 3 I declare that the averments of fact set forth in this Affidavit are true and correct to the best of my knowledge, information, and belief. I declare under penalty of perjury that the foregoing is true and correct.

Executed on: 4/19/2022 Signed electronically by Zachary Harper