RA-23-0052, Refuel 32 (O1R32) Inservice Inspection (ISI) Report, Fifth 10-Year ISI Interval

Refuel 32 (O1R32) Inservice Inspection (ISI) Report, Fifth 10-Year ISI Interval

ML23053A057
Person / Time
Site:	Oconee
Issue date:	02/22/2023
From:	Ellis K Duke Energy Carolinas
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
RA-23-0052
Download: ML23053A057 (1)

Text

e_(,DUKE KevinM.Ellis

~ J ENERGY General Manager Nuclear Regulatory Affairs, Policy &

Emergency Preparedness Duke Energy 13225 Hagers Ferry Rd., MG011 E Huntersville, NC 28078 843-951-1329 Kevin.Ellis@duke-energy.com RA-23-0052 February 22, 2023 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Oconee Nuclear Station, Unit 1 Docket No. 50-269 Renewed License No. DPR-38

Subject:

Oconee Unit 1, Refuel 32 (01 R32) lnservice Inspection (ISi) Report, Fifth 10-Year ISi Interval Pursuant to the 2007 Edition through the 2008 Addenda of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, IWA-6000, Duke Energy Carolinas, LLC is providing its lnservice Inspection (ISi) summary pertaining to the 32 nd refueling outage (01 R32) for Oconee Nuclear Station (ONS) Unit 1.

The enclosure contains the 01 R32 ISi summary report.

This submittal contains no regulatory commitments. Please refer any questions regarding this submittal to Ryan Treadway, Director- Nuclear Fleet Licensing, at 980-373-5873.

Sincerely, Kevin M. Ellis General Manager - Nuclear Regulatory Affairs, Policy & Emergency Preparedness JLV

Enclosure:

lnservice Inspection Summary Report Unit 1 Oconee Fall 2022 Refueling Outage 01 R32 (Outage 5)

U.S. Nuclear Regulatory Commission RA-23-0052 Page 2 cc: (with Enclosure)

Ms. Laura Dudes Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Avenue NE, Suite 1200 Atlanta, GA 30303-1257 Mr. Shawn Williams NRC Senior Project Manager Oconee Nuclear Station Mr. Jared Nadel NRC Senior Resident Inspector Oconee Nuclear Station

Enclosure to RA-23-0052 Enclosure Inservice Inspection Summary Report Unit 1 Oconee Fall 2022 Refueling Outage O1R32 (Outage 5)

[9 pages follow this cover page]

DUKE ENERGY INSERVICE INSPECTION

SUMMARY

REPORT UNIT 1 OCONEE FALL 2022 REFUELING OUTAGE O1R32 (Outage 5)

Location: 7800 Rochester Hwy, Seneca, SC 29672 NRC Docket No. 50-269 Commercial Service Date: July 15, 1973 Owner: Duke Energy Revision 0 Digitally signed by ACKell1 (365600)

Date: 2023.02.13 14:59:39 -05'00' Originated By: Date Austin C. Keller Digitally signed by JMB9947 (107526)

Date: 2023.02.13 15:06:24 -05'00' Checked By: Date Jim Boughman MAP9681 Digitally signed by MAP9681 (102140)

Approved By: (102140) Date: 2023.02.13 15:27:26 -05'00' Date Mark A. Pyne

CASE N-532-5 FORM OAR-1 OWNER'S ACTIVITY REPORT Report Number Owners Activity Report for Refueling Outage O1R32 Plant Oconee Nuclear Station, 7800 Rochester Highway, Seneca, SC 29672 Unit No. 1 Commercial service date 07/15/1973 Refueling outage no. O1R32 (if applicable)

Current inspection interval Fifth Inspection Interval (ISI), Third Inspection Interval (Containment ISI)

(1st, 2nd, 3rd, 4th, other)

Current inspection period Third Inspection Period (ISI and Containment ISI)

(1st, 2nd, 3rd)

Edition and Addenda of Section XI applicable to the inspection plans ASME Section XI 2007 Edition through 2008 Addenda Date and revision of inspection plans See Attachment A Edition and Addenda of Section XI applicable to repair/replacement activities, if different than the inspection plans Same as above The following Code Cases are permitted by the Augmented ISI, ISI, and Pressure Test Plans, 5th Interval: N-513-3, N-513-4, N-532-4, N-532-5, N-586-1, N-600, N-613-1, N-613-2, N-639, N-643-2, N-648-1, N-648-2, N-651, N-663, N-705, N-706-1, N-711-1, N-712, N-716-1, N-722-1, N-729-4, N-729-6, N-731, N-735, N-751, N-765, N-770-2, N-770-5, N-771, N-775, N-Code Cases used for inspection 776, N-786-1, N-798, N-800, N-805, N-823, N-823-1, N-825, N-831, N-843, and evaluation: N-845, N-853, & N-854 (if applicable)

CERTIFICATE OF CONFORMANCE I certify that (a) the statements made in this report are correct; (b) the examinations and tests meet the Inspection Plan as required by the ASME Code,Section XI; and (c) the repair/replacement activities and evaluations supporting the completion of O1R32 conform to the requirements of Section XI.

(refueling outage number)

Digitally signed by ACKell1 (365600)

Date: 2023.02.13 14:59:55 Signed -05'00' Austin C. Keller, ISI Program Owner Date 02/13/2023 CERTIFICATE OF INSERVICE INSPECTION I, the undersigned, holding a valid commission issued by the National Board of Boiler and Pressure Vessel Inspectors and the State or Province of South Carolina and employed by Bureau Veritas Inspection and Insurance Company of Lynn, MA have inspected the items described in this Owners Activity Report, and state that, to the best of my knowledge and belief, the Owner has performed all activities represented by this report in accordance with the requirements of Section XI.

By signing this certificate neither the Inspector nor his employer makes any warranty, expressed or implied, concerning the repair/replacement activities and evaluation described in this report. Furthermore, neither the Inspector nor his employer shall be liable in any manner for any personal injury or property damage or a loss of any kind arising from or connected with this inspection.

Digitally signed by MEZurbu (285214)

MEZurbu (285214) Date: 2023.02.16 13:27:04 -05'00' Commissions 13048, 201, AI, IS, N, I, C, R Inspectors Signature National Board, State, Province, and Endorsements Mark E. Zurbuch Date 2/16/2023 Page 1 of 8

CASE N-532-5 Attachment A Oconee Unit 1 Refueling Outage 32, Inservice Inspection Report The Oconee Nuclear Station Unit 1 Fifth Ten Year Inservice Inspection (ISI) Plan complies with 10CFR50.55a, which implemented, by reference, the American Society of Mechanical Engineers (ASME)

Boiler and Pressure Vessel Code,Section XI, 2007 Edition with 2008 Addenda.

x Per RIS 2004-12, Letter RA-20-0262, NRC Accession Number ML20260H325 and approval NRC Accession Number ML20300A206, the NRC staff concluded that the use of subparagraph IWA-4540(b) of the 2017 Edition of the ASME B&PV Code,Section XI, is acceptable for Oconee Unit 1.

x Per RIS 2004-16, Letter RA-20-0263, NRC Accession Number ML20260H326 and approval NRC Accession Number ML21113A013, the NRC staff concluded that the use of subparagraph IWA-4340 of the 2017 Edition of the ASME B&PV Code,Section XI, is acceptable for Oconee Unit 1.

x Per RIS 2004-12, Letter RA-20-0191, NRC Accession Number ML20265A028 and approval NRC Accession Number ML21029A335, the NRC staff concluded that the use of paragraphs IWA-5120, IWA-5213, IWA-5241, IWA-5242, and IWA-5250 of the 2017 Edition of the ASME B&PV Code,Section XI, is acceptable for Oconee Unit 1.

This summary report is being submitted pursuant to the reporting requirements of ASME Section XI as amended by ASME Code Case N-532-5, Repair/Replacement Activity Documentation Requirements and Inservice Inspection Summary Report Preparation and Submission Section XI, Division 1.

Contained within this summary report are the form OAR-1 (Owners Activity Report) and Tables 1 and 2 of Code Case N-532-5 for Oconee Nuclear Station during cycle 32 and Refueling Outage 32 (O1R32).

O1R32 is the last outage of the third ISI period in the fifth inspection interval. O1R32 is the last outage of the third Containment period in the third inspection interval. This report reviewed all Repair/Replacement activities from November 19, 2020 through November 24, 2022, cycle 32.

Date and Revision of Inservice Inspection Plans:

I. Fifth Interval Inservice Inspection Plans

1. The following documents comprise the Oconee Nuclear Station 5th Interval Inservice Inspection Plan for ONS Unit 1 (Class 1, 2, and 3 Components):

a. ISI Plan - Fifth Interval Inservice Inspection Plan, Oconee Nuclear Station Units 1, 2, & 3 and Keowee Hydro Station Units 1 & 2, Document #OISI-0169.10-0050-ISI PLAN, Rev.

2, dated 08/22/22.

b. ISI Schedule - Fifth Ten-Year Interval Inservice Inspection Schedule Oconee Nuclear Station Unit 1, Document #OISI-0169.10-0050-Unit 1, Rev. 2, dated 08/16/22.

2. The following document comprises the Oconee Nuclear Station 5th Interval Inservice Inspection Pressure Test Plan for ONS Unit 1:

a. Oconee Nuclear Station - Fifth Inspection Interval Inservice Inspection PT (Pressure Test) Plan General Requirements Units 1, 2, and 3, Document #OISI-0169.20-0050-PTPLAN, Rev. 8, dated 07/21/2022.

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CASE N-532-5 II. Fifth Interval Augmented Inservice Inspection Plan

1. The following document comprises the Oconee Nuclear Station 5th Interval Augmented Inservice Inspection Plan and Schedule for Unit 1:

a. Oconee Nuclear Station - Augmented Inservice Inspection NDE Plan - General Requirements and Units Detail Listing, Document #OISI-0169.10-0050 - AUG-ISI, Rev. 8, dated 09/06/2022.

III. Third Interval Containment Inservice Inspection Plan

1. The following document comprises the Oconee Nuclear Station 3rd Interval Containment Inservice Inspection Plan for Unit 1 (Class MC):

a. Third Interval Containment Inservice Inspection Plan Oconee Nuclear Station Units 1, 2,

& 3, Document #O-ISIC3-62-0001, Rev. 9, dated 05/01/2022.

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CASE N-532-5 TABLE 1 ITEMS WITH FLAWS OR RELEVANT CONDITIONS THAT REQUIRED EVALUATION FOR CONTINUED SERVICE Examination Category and Item Description Evaluation Description Item Number Indications identified in NCR 02448007 ISI Summary No. O1-09560 (Component ID were evaluated by Engineering and 1-SCV-011). VT-1 examination revealed two found to be acceptable for continued

• E-C / E4.11 locations that exhibited pit readings of 0.047 service per IWE-3122.3. Successive and 0.039 with wall loss exceeding 10% of exams per IWE-2420 are required for the nominal (0.25) thickness. the 1st period of the 4th Containment ISI Interval.

Accepted for continued service by the Responsible Engineer per IWL-3212.

L-A / L1.11 All Accessible Surface Areas Indications documented in WO # 20376931-37.

Tendons 2D10 (End 1) and 2D14 (End 1)

Accepted for continued service by the L-B / L2.30 were found to have concrete cracking Responsible Engineer per IWL-3222.

adjacent to the tendon anchorage.

Tendon 3D05 had a low reserve alkalinity Accepted for continued service by the L-B / L2.40 value. Responsible Engineer per IWL-3222.

Tendons 45V25, 56V24, 61V28, 45V12, 23V30, 34V7, 24H39, 46H100, 35H63, Accepted for continued service by L-B / L2.40 3D05, 2D14, and 1D54 had grease net duct Responsible Engineer per IWL-3222.

volume changes greater than 10%.

• - See information required by 10 CFR 50.55a(b)(2)(ix)(A) on Attachment B of this report.

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CASE N-532-5 TABLE 2 ABSTRACT OF REPAIR/REPLACEMENT ACTIVITIES REQUIRED FOR CONTINUED SERVICE Repair /

Code Date Item Description Description of Work Replacement Class Completed Plan Number 1B2 HPI Nozzle-to-Safe End Weld Overlay per EC 421842.

1-RC-NZ-0004 1 Reference NCR # 02447967 11/16/2022 20567604-01 (1B2 HPI Nozzle) and Event Notification # 56197.

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CASE N-532-5 Attachment B Containment Liner Plate I. Requirements per 10 CFR 50.55a(b)(2)(ix)(A)(2)

(2) For each inaccessible area identified for evaluation, the applicant or licensee must provide the following in the ISI Summary Report as required by IWA-6000:

(i) A description of the type and estimated extent of degradation, and the conditions that led to the degradation; (ii) An evaluation of each area, and the result of the evaluation; and (iii) A description of necessary corrective actions.

II. A description of the type and estimated extent of degradation, and the conditions that led to the degradation

a. Description of Degradation During ONS Unit 1 refueling outage O1R32 (Fall 2022), Category E-C, Item No. E4.11 examination on Component ID 1-SCV-011 (Summary Number O1-09560) pitting of the carbon steel containment metallic liner plate located behind to the removable inspection port was identified. Only two locations were identified that exhibited pit depths of approximately 0.047 and 0.039. These readings were obtained using a V-Wac gauge. These two areas exceeded the 10%

wall thickness (0.25 nominal liner thickness) and therefore were visually unacceptable.

In addition to the visual (VT-1) exam, the containment liner plate within the inspection port received a UT thickness exam under Category E-C, Item No. E4.12, Component ID 1-GRID-001 (Summary No. O1-09561). These readings were satisfactory and validated sufficient adjacent wall thickness of 0.272.

b. Estimated Extent of Degradation Based on results of evaluation conducted in accordance with NCR# 02448007 performed during refueling outage O1R32, the estimated extent of degradation is as follows:

i. The pitting was limited to the surfaces of the containment liner plate behind the inspection port. Based on examinations during the Unit 1 refueling outage O1R32, it can be concluded that the sealant material around the inspection port has not been completely effective in preventing moisture intrusion to inaccessible embedded surfaces of the containment metallic liner adjacent to the inspection port. All remaining moisture barriers outside of the inspection port moisture barrier were inspected and found acceptable during O1R32. Additionally, all moisture barriers including the inspection port moisture barrier are inspected each inspection period per the Containment ISI Plan (File No. O-ISIC3-62-0001).

ii. Due to prior moisture barrier degradation and observed moisture intrusion it is estimated that nearly all the periphery of the liner plate beneath the embedment zone has been exposed to moisture. Therefore, the liner plate behind inspection port serves as a leading indicator for corrosion of the metallic liner plate based on the fact that it is more difficult to maintain a water tight seal around the inspection port and the liner plate was left uncoated.

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CASE N-532-5

c. Description of Conditions That Led to the Degradation Based on operating experience from previous examinations conducted in accordance with ASME Section XI, Section IWE, the following conclusions were drawn about the conditions that led to the degradation.

i. Maintenance activities (end of outage washdowns) inside the Reactor Building have created the source of moisture observed in the moisture barrier between the containment metallic liner and concrete inspection port.

ii. Degradation of sealant materials at embedment zones has allowed moisture to gain access to inaccessible surfaces of the containment metallic liner behind the inspection port.

III. Evaluation of each area and the result of the evaluation (Reference NCR# 02448007)

ASME Boiler and Pressure Vessel Code,Section XI, Division 1, Subsection IWE, Requirements for Class MC and Metallic Liners of Class CC Concrete Components of Light Water-Cooled Power Plants", 2007 edition with 2008 Addenda is the applicable code for IWE examinations at ONS during the 3rd Containment Inservice Inspection Interval.

The liner plate at the location of the inspection plug below the concrete floor is 1/4" thick A-36 material. Per the applicable code referenced above, IWE-3522 requires an engineering evaluation when material loss greater than 10% is detected in a local area. These areas must be accepted by engineering evaluation or corrected by repair/replacement activities in accordance with IWE-3122.

Supplemental examinations must be performed in accordance with IWE-3200.

10% of the 0.25" liner plate is 0.025". While the UT readings showed material loss less than 10% of nominal, the pit gauge readings exceeded 10% in 2 localized areas. The pits were measured as approximately 0.047 and 0.039". The UT readings showed a thickness of 0.272" in this area. 0.272-0.047(the larger of the 2 pits)=0.225".

The post tensioned reactor building tendons in general maintain a compressive stress on the concrete shell and liner plate at all times. Pressures associated with accident conditions reduce the compressive stress and there is not a significant stress reversal that could potentially cause the pitted areas to rupture under high tensile stresses. The liner plate function is to maintain a leak tight barrier.

Because the liner plate is not pressure retaining, significantly less than 90% of the thickness is required to maintain design function. Any forces applied to the liner plate would be applied across the surface of the plate. Sufficient reinforcement is provided by the adjacent thicker liner plate. Therefore, any stresses that would be experienced by the plate are acceptable. Additionally, the UT shows the plate in this location is greater than 0.25". At the deepest pit the liner plate is still 0.225" thick which is equivalent to a 10% loss of a 0.25" thick plate.

The liner plate findings are acceptable by engineering evaluation (IWE-3122.3). This area is scheduled for reinspection during the first period of the 4th Containment Inservice Inspection Interval per IWE-2420, Successive Inspections.

IV. A description of necessary corrective actions

a. Immediate Corrective Actions

i. Shell metallic liner plate surfaces were cleaned and inspected.

ii. The inspection port was re-installed with new sealant material between the inspection port and containment metallic liner. The metallic containment liner coating behind the inspection port was removed in order to allow accurate UT readings. Also, the coating was not re-Page 7 of 8

CASE N-532-5 applied at the end of O1R32 in order for the uncoated liner behind the inspection port to serve as a leading indicator for accelerated corrosion compared to the remaining periphery embedded liner that is coated.

iii. The Third Interval Containment Inservice Inspection Plan (O-ISIC3-62-001) requires that this area be visually inspected (VT-1) and UT readings taken each period with the next inspection scheduled for O1R33 (Fall, 2024). Upon successful examination results in O1R33 and no additional corrosion compared to the results from O1R32, the uncoated metallic liner is planned to be recoated and the pitting condition will subsequently be accepted via IWE-3122.2 (Corrective Measure).

b. Long-Term Corrective Actions

i. Degradation of moisture barriers is an indicator that there is potential for moisture to access portions of the metallic shell liner which are inaccessible. Since the risk of moisture intrusion is greatest at the inspection port located at azimuth 30° in the Unit 1 Reactor Building interior basement, it was determined that augmented examinations will continue to be performed on at this inspection port embedment zone. This exam will be included in Category E-C of the 4th Interval ONS Containment ISI Plan. These exams be re-evaluated at the end of the 1st period of the 4th Containment ISI Interval based on examination results from O1R33 (1st outage of the 4th interval).

ii. All remaining Containment moisture barriers are examined in accordance with ASME Category E-A, Item Number E1.30 each inspection period. Periodic examination in accordance with ASME Code ensures continued maintenance and reliability of all remaining moisture barriers.

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