View source for RA-19-0426, Supplement to RA-18-0138, Oconee Unit 3, Refuel 29 (O3R29) Inservice Inspection and Steam Generator Inspection (SG-ISI) Report, Fifth 10-Year ISI Interval

{{Adams
| number = ML19343A022
| issue date = 12/09/2019
| title = Supplement to RA-18-0138, Oconee Unit 3, Refuel 29 (O3R29) Inservice Inspection and Steam Generator Inspection (SG-ISI) Report, Fifth 10-Year ISI Interval
| author name = Dalton S
| author affiliation = Duke Energy Carolinas, LLC
| addressee name = 
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000287
| license number = DPR-055
| contact person = 
| case reference number = RA-19-0426
| document type = Inservice/Preservice Inspection and Test Report, Letter type:RA
| page count = 12
}}

=Text=
{{#Wiki_filter:Sheila Dalton
(-,DUKE                                                                         Manager- Nuclear Support Services Oconee Nuclear Station ENERGYQD                                                                                         Duke Energy ONO 1 VP I 7800 Rochester Hwy Seneca, SC 29672 864.873.3657 Sheila. Dalton@duke-energy.com Serial: RA-19-0426                                                            10 CFR 50.55 December 09, 2019 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 OCONEE NUCLEAR STATION, UNIT NO. 3 DOCKET NO. 50-287 / RENEWED LICENSE NO. DPR-55

==SUBJECT:==
Supplement to RA-18-0138, Oconee Unit 3, Refuel 29 (O3R29) lnservice Inspection and Steam Generator Inspection (SG-ISI) Report, Fifth 10-Year ISi Interval

==REFERENCES:==
: 1. Duke Energy Letter, Oconee Unit 3, Refuel 29 (O3R29) lnservice Inspection (ISi) and Steam Generator Inspection (SG-ISI) Report, Fifth 10-Year/SI lnterval(RA-18-0138),
August 15, 2018 (ML18235A502).
Ladies and Gentlemen:
By letter dated August 15, 2018 Duke Energy Carolinas, LLC (Duke Energy) submitted the Oconee Unit 3, Refuel 29 (O3R29) lnservice Inspection (ISi) and Steam Generator lnservice Inspection (SG-ISI) Report (Reference 1). Duke Energy has provided Revision 1 to the O3R29 ISi reRort as Enclosure 1 to this letter. This revision adds an additional item to Table 1 of the original ISi report and includes supporting information required by 10 CFR 50.55a(b)(2)(ix)(A).
This revision supersedes Enclosure 1 of RA-18-0138 (Reference 1 ).
This submittal contains no new regulatory commitments. Should you have any questions concerning this letter, or require additional information, please contact Art Zaremba, Manager -
Nuclear Fleet Licensing, at 980-373-2062.
Sincerely, Sheila Dalton Manager - Nuclear Support Services, Oconee Nuclear Station

U.S. Nuclear Regulatory Commission                                            Page 2 Serial: RA-19-0426

==Enclosure:==
: 1. Owners Report for Inservice Inspections, Oconee Unit 3, O3R29 (Outage 2, Spring 2018), Revision 1.
cc:     (w/ enclosure)
A. Klett, NRC Project Manager, NRR L. Dudes, NRC Regional Administrator, Region II J. Nadel, NRC Sr. Resident Inspector, Oconee Nuclear Station

U.S. Nuclear Regulatory Commission                                  Enclosure 1 Serial: RA-19-0426 Enclosure 1 Owners Report for Inservice Inspections, Oconee Unit 3, O3R29 (Outage 2, Spring 2018),
Revision 1

Inservice Inspection Related Code Case N-532-5 OAR-1 Report Unit 3 Document

==Title:==
OCONEE NUCLEAR STATION UNIT FIFTH INTERVAL INSERVICE INSPECTION NDE OAR-1 REPORT/ PERIOD 1 / OUTAGE 2 / O3R29 Rev: 001 Document Index Number: OISI-0169.10-0050 - O3R29-OAR-1 Record Retention Number: 421734 Document Owner: Austin C. Keller Q. A. CONDITION 1 VERIFY HARD COPY AGAINST FUSION PRIOR TO EACH USE

CASE N-532-5 OWNER'S ACTIVITY REPORT for INSERVICE INSPECTIONS OCONEE UNIT 3 2018 Refueling Outage O3R29 (Outage 2)
Plant Location: 7800 Rochester Hwy, Seneca, SC 29672 NRC Docket No. 50-287 Commercial Service Date: December 16, 1974 Owner: Duke Energy Carolinas 526 South Church St.
Charlotte, NC 28201-1006 Revision 1 Originated By:
Checked By:                                                  Dute - -10/7/ 19 Approved By:                                                 Date   It>Mt

CASE N-532-5 FORM OAR-1 OWNER'S ACTIVITY REPORT R.eport Number                              _ _O_w_ner's Activity Report for Unit 3 Operating Cycle _2_9_ _ _ _ _ __
Plant                                  Oconee Nuclear Station, 7800 Rochester Highway, Seneca, SC 29672 Unit No.             3             Commercial service date                 12/16/1974                    Refueling outage no.        03R29_ _ __
Current inspection interval          5th fo1* Class Current inspection period            1st for Class 1, 2, & 3 Components & Supports and Class MC Containment Edition and Addenda of Section XI applicable to the inspection plans                                    2007 Edition through the 2008 Addenda Date and revision of inspection plans                   See Attachment A Edition and Addenda of Section XI applicable to repair/replacement activities, if difforent than the inspection plans Samg Code Cases used*               The fo:lowing Code Cases are permitted by the ISi P,ans: N-513-3, N-532.-5, N-586-1, N-613-1, N-6:19, N-643,2, i~-
6481, N-663, N-706:h__l'!-711!~-716-l, r~-722-1, N-73_9~4, N:J31,_~,_*--_!3_5~,_N_-7_7u_--_2 _______
(i+ nrm1ic;,b11;-;)
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 XL and (c) the repair/replacement activities and evaluations supporting the completion of 03R29 conform to the requirements of Section XI.
Signed                                                         Austin C                                     Owner             Date Ownt*( or Owner's Designc*c, nt!e 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 Carnlina and employed by OneCIS Insurance Company Lynn MA have inspected the items described in this Owne1's 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 cert1ficdte neither the Inspector nor his employer makes any warranty, expressed or implied, concerning the repairireplacement 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 frorn or connected with this inspection.
Cornrrds~ions       13048, 201, AI, IS, N, I, C, R
--------------------------------                                                                                ----------~-------------
Mark E. Zurbuch 10/17/19 L-----==================='---------------------------~
Date OAR-1                                                          ONS 03R29                                                               Page 1 of 7

Attachment A                                       CASE Date and Revision of Inspection Plans:                   N-532-5 Oconee Unit 3 Refuel 29, Inservice Inspection Report
: 1. The following documents comprise the Oconee Nuclear Station 5th Interval Inservice NDE Inspection Plan for Unit 3 (Class 1, 2, and 3 Components):
: a. Oconee Nuclear Station - Fifth Interval Inservice Inspection Plan General Requirements Units 1, 2, and 3, Document #OISI-0169.10-0050-GEN REQ, Rev. 1, dated 10/13/2015, including the following addenda:
: i. OISI-0169.10-0050-5ONS-003 ii. OISI-0169.10-0050-5ONS-004
: b. Oconee Nuclear Station Unit 3 - Fifth Interval Inservice Inspection Plan General Requirements, Document #OISI-0169.10-0050-GEN REQ, Rev. 1, dated 10/13/2015, including the following addenda:
: i. OISI-0169.10-0050-5ONS3-007 through OISI-0169.10-0050-5ONS3-018
: 2. The following documents comprise the Oconee Nuclear Station 5th Interval Inservice Inspection Pressure Test Plan for Unit 3:
: 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. 3, dated 08/21/2019, including the following addenda:
: i. None
: 3. The following documents comprise the Oconee Nuclear Station 3rd Interval Containment Inservice Inspection Plan for Unit 3 (Class MC):
: a. Oconee Nuclear Station - Third Inspection Interval Containment Inservice Inspection Plan Oconee Nuclear Station Units 1,2, & 3 - Document # O-ISIC3-62-0001, Rev. 6, dated 09/24/2019, including the following addenda:
: i. None OAR-1                                          ONS O3R29                                    Page 2 of 7

Attachment A                                         CASE Date and Revision of Inspection Plans:                       N-532-5 Oconee Unit 3 Refuel 29, Inservice Inspection Report Table 1 Items With Flaws or Relevant Conditions that Required Evaluation for Continued Service Examination Category and Item Number                        Item Description                           Evaluation Description ISI Summary No. O3.F1.22.0004.                 Indication identified in NCR# 22000440 was F-A / F1.22      The VT-3 examination revealed the west         evaluated by Engineering and found to be spring can indication was out of tolerance. acceptable for continued service.
ISI Summary No. O3.F1.22.0015.                 Indication identified in NCR# 02186273 was F-A / F1.22      The VT-3 examination revealed the west         evaluated by Engineering and found to be spring can indication was out of tolerance. acceptable for continued service.
Indication identified in NCR# 02203514 and CISI Summary No. E04.12.0001 (#3-GRID-001).
NCR # 02202977 was evaluated by
   *E-C / E4.12      The UT thickness examination revealed Engineering and found to be acceptable for surface pitting of the liner plate.
continued service.
* - See information required by 10 CFR 50.55a(b)(2)(ix)(A) on Attachment B of this report.
Table 2 Abstract of Repair/Replacement Activities Required For Continued Service Code                                                                                     Repair/Replacement Item Description             Description of Work      Date Completed Class                                                                                        Plan Number Repair volumetric 2           3HPI-TK-0001            Indications @ support leg      05/05/18              WO 20112790-13 attachment weld Replace 1/4" piping at pin 2           3LPS-IV-0089                                           07/09/18               WO 20253064 hole leak U3 TDEFWP Recirc Replace piping due to 3      Piping D/S of 3FDW-88                                       05/24/18               WO 20253553 through wall leak and 89 Replace piping flange due 3            0SF-FE-0001                                           04/27/18               WO 20236398 to pin hole leak OAR-1                                                    ONS O3R29                                     Page 3 of 7

Attachment B                                         CASE Containment Liner Plate                            N-532-5 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. Acceptability Evaluation of Inaccessible Areas per 10 CFR 50.55a(b)(2)(ix)(A)(1)
The inaccessible metallic liner plate surfaces beneath the embedment zone at the interface between the containment liner plate and basement concrete floor have sufficient design margin against corrosion and are excluded from the scope of items requiring augmented examination in accordance with IWE-1241(a). This evaluation is documented in NCR # 02203514-04.
III. 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 3 refueling outage O3R29 (Spring 2018), Category E-C examination on Component ID 3-SCV-011 (Item Number E04.11.0005) pitting of the carbon steel containment metallic liner plate located adjacent to the removable inspection port was identified. In addition to the visual exam, the containment liner plate within the inspection port received a UT thickness exam under Category E-C, Component ID 3-GRID-001 (Item Number E4.12.0001).
: b. Estimated Extent of Degradation Based on results of evaluation conducted in accordance with NCR# 02203514 and additional examinations conducted during refueling outage O3R29, the estimated extent of degradation is as follows:
: i. The pitting was limited to the surfaces of the containment liner plate within inspection port area. Based on examinations during the Unit 3 refueling outage O3R29, it can be concluded at 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. The remaining periphery moisture barrier around the containment metallic liner has been effective, since replacement of the moisture barrier per modification ONOE- 9688, Unit 3 (WO# 96093224) corrected existing degradation. All remaining moisture barriers outside of the inspection port moisture barrier were inspected and found acceptable during O3R29. Additionally, all moisture barriers including the inspection port moisture barrier are inspected every inspection period and will be inspected next refueling outage (O3R30) per the Containment ISI Plan (File No. O-ISIC3                         0001).
OAR-1                                          ONS O3R29                                      Page 4 of 7

Attachment B                                          CASE Containment Liner Plate                            N-532-5 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 inspection port due to its degraded moisture barrier and based on the fact that it is more difficult to maintain the seal around the inspection port, serves as a leading indicator for corrosion of the metallic liner plate.
: 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.
IV. Evaluation of each area and the result of the evaluation (Reference NCR# 02203514)
The applicable code for IWE examinations at ONS during the 3rd Containment ISI inspection interval is 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. NCR 2202977 documents UT readings and pit gauge readings of the U3 liner plate at SCV-011. This area is at azimuth 30&deg; in the reactor building basement and is visible when the inspection port plug is removed. The liner plate at this location is 1/4" A36 material. Per the applicable code referenced above, Section IWE-3522 requires liners of Class CC pressure-retaining components that detect material loss in a local area exceeding 10% of the nominal wall thickness shall be documented and evaluated by engineering or corrected in accordance with IWE-3122. Averaging UT data taken, the actual thickness of the liner plate in this area is 0.259". Pit gauge readings were taken and the largest pit depth is 1/16". Based on UT readings taken right around the pit the thinnest location is 0.2545" - 0.0625"= 0.192" which is more than a 10% loss of the 1/4" material. The basis for the 10% allowed loss is documented in Appendix A of DPM-1226.00-0002-001, Specification for Evaluation and Acceptance of local areas of Material, Parts, and Components that are less than the Specified Thickness. Appendix B of the same document discusses the basis for local surface conditions. Appendix B demonstrates that, in most cases, if the remaining thickness after erosion or corrosion is greater than 1/2 the required thickness of the component, Code requirements are met. 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, which would then prevent the liner plate from performing its design function of maintaining 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 OAR-1                                          ONS O3R29                                       Page 5 of 7

Attachment B                                         CASE Containment Liner Plate                           N-532-5 thicker liner plate. Therefore, any stresses that would be experienced by the plate are acceptable. The inspection port at this location was installed to monitor the condition of the liner plate at and just below the floor slab. The intent was for this location to be representative of the remainder of the liner plate in the same location around the building. With the coating removed any future readings would be more conservative and serve as a leading indicator for the remainder of similar areas which are coated. 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 O3R30 (Spring, 2020). Since the next inspection is scheduled next outage engineering believes leaving this area uncoated is acceptable. The moisture barrier at the concrete to liner plate interface and around the inspection port plug was re-applied after the inspection port was re-installed. Any exposed uncoated liner above the base slab was recoated. WR 20107216 was written to install coating to the liner plate in the Azimuth 30&deg; floor plug after NDE has performed their exam (VT-1 and UT) during O3R30.
V. 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-applied at the end of O3R29 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 O3R30 (Spring, 2020). Since the next inspection is scheduled next outage engineering believes leaving this area uncoated is acceptable. Upon successful examination results in O3R30 and no additional corrosion compared to the results from O3R29, the uncoated metallic liner will 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. The acceptability of the metallic shell surfaces has been addressed previously under NCR # 02202977 and these surfaces have been evaluated by engineering to be acceptable. Because the risk of moisture intrusion is greatest at the inspection port located at azimuth 30&deg; in the Unit 3 Reactor Building interior basement, it was determined that additional examinations need be performed only on the moisture barrier at this inspection port embedment zone. Therefore, a general visual exam of the inspection port moisture barrier will increase from once a OAR-1                                            ONS O3R29                                      Page 6 of 7

Attachment B                                     CASE Containment Liner Plate                          N-532-5 period to every outage at ONS Unit 3. This exam will be included in Category E-C of the ONS Containment ISI Plan. This increased exam frequency of the inspection port moisture barrier is commensurate with the degradation mechanism (water instruction) associated with the pitting of the metallic liner plate behind the inspection port. These exams will continue for the remainder of the 3rd Containment ISI Interval and will be re-evaluated at the beginning of the 4th Containment ISI Interval based on examination results.
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.
OAR-1                              ONS O3R29                                   Page 7 of 7}}