ML25058A351
| ML25058A351 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 02/27/2025 |
| From: | Jenkins B Dominion Energy South Carolina |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 25-027 | |
| Download: ML25058A351 (1) | |
Text
Dominion Energy South Carolina V. C. Summer Nuclear Station Bradham Boulevard & Highway 215, Jenkinsville, SC 29065 Mailing Address:
P.O. Box 88, Jenkinsville, SC 29065 Dominion Energy.com Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555 February 27, 2025 DOMINION ENERGY SOUTH CAROLINA (DESC)
VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1
~
Dominion p
Energy Serial No.25-027 VCS LIC/HK/Rev 0 Docket No. 50-395 License No. NPF-12 INSERVICE INSPECTION (ISi) OWNER'S ACTIVITY REPORT (OAR) FOR REFUELING OUTAGE 28 In accordance with the requirements of American Society of Mechanical Engineers (ASME)
Code Cases N-532-5 and N-892, enclosed is the lnservice Inspection (ISi) Owner's Activity Report (OAR) covering ISi activities associated with the first outage of the first period of the fifth ISi interval (Enclosure 1 ). Also enclosed is the Containment lnservice Inspection (CISI)
Responsible Engineer Evaluation Report associated with the first outage of the third period of the third CISI interval (Enclosure 2).
Should you have any questions regarding this submittal, please call Mr. Michael Moore at (803) 345-4752.
Sincerely,
- 6~
Beth Slmkins
~
Site Vice President V.C. Summer Nuclear Station
Enclosures:
- 1) lnservice Inspection Owner's Activity Report for Refueling Outage 28, Report Number 27
- 2) Containment lnservice Inspection - 2024 (RF-28), ASME Section XI, Subsections IWE and IWL, Responsible Engineer Evaluation Report Commitments contained in this letter: None cc:
(Without Enclosures Unless Indicated)
G. J. Lindamood - Santee Cooper L. Dudes - NRC Region II G. Miller - NRC Project Mgr.
NRC Resident Inspector Authorized Nuclear lnservice Inspector
VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) Unit 1 DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 ENCLOSURE1 Serial No.25-027 INSERVICE INSPECTION OWNER'S ACTIVITY REPORT FOR REFUELING OUTAGE 28, REPORT NUMBER 27
FORM OAR-1 OWNER'S ACTIVITY REPORT Report Number _________________
l_n_se_rv_ic_e_l_n_sp_e_c_t_io_n_R_e_p_o_rt_#_2_7 ________________ _
Plant ____________
v_.c_._s_u_m_m_er_N_u_c_le_a_r_S_t_at_io_n_,_P_,o_. B_o_x_aa_,_J_e_n_ki_n_sv_il_le_,_s_c_2_9_0_6_5 ___________ _
Unit No. _______
1 ______ Commercial service date ___
Ja_n_u_a_ry"--1-* _19_8_4 ___ Refueling outage no. __
R_F-_2_8 __
(if applicable)
Applicable inspection interval ______________
l_S_I...,.-_5_th_In,..te_rv-:--a--,l;_C_IS.,...I_-,..3_r_d_l_nt_e_rv_a_l _____________ _
(1st,, 2nd, 3rd, 4th, other)
Applicable inspection period ______________
I_S_I _-_1s...,.t_P_e_r_io_d_;..,.c_IS_l -_3_r_d_P_e_n_*o_d _____________ _
(1st, 2nd, 3rd)
Edition arid Addenda of Section XI applicable to the inspection plans __
I_S_I -_2_0_1_9_E_d_i_lio_n_;_C_IS_l_-_2_0_0_7_E_d_it_io_n_th_r_o_u.;;.gh_2_00_8_A_d_de_n_d_a __
Date and revision of inspection plans ________
IS_l_-_121_2_9_/2_0_2_3_R_e_v_is_i_o_n_O_; _C_IS_l_-_1_1_/0_4_/_2_02_2_R_e_vi_s_io_n_3_F _______ _
Edition and Addenda of Section XI applicable to repair/replacement activities, if differentthan the inspection plans NIA Code Cases used for inspection and evaluation: _____
N_-_5_3_2_-5_,_N_-_7_1_6_-2_,_N_-_7_2_2-_1_, _N_-7_7_0_-_5_
1 _N_-8_3_1_-1_,_N_-_8_6_4_, a_n_d_N_-8_9_2 ____ _
(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, S~ection XI; and (cl the repair/replacement activities and evaluations supporting the completion of ______
R_F_-2_8 ______ conform to the re ire
~de,Section XI.
(refueling outage number)
Signed Supervisor, Nuclear Engineering ISi and NOE Programs Date __
0_2_/_2_7_/_2_0_2_5 ________ _
(Owner or Owner's Designee. Title)
CERTIFICATE OF INSERVICE INSPECTION I, the undersigned, holding a valid commission issued by the National Board of Boile'r ahd Pressure Vessel Inspectors and employed by The Hartford Steam Boiler Inspection and Insurance Company of Hartford, Corinecticut have inspected the items described in this Owner'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 the ASME Code,Section XI.
By signing this certificate, neither the Inspector nor his employer makes any warranty, expressed or implied, concerning the repair/replacement activities and evaluations 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 loss of ahy kind arising from or connected with this inspection.
---~-~--,-~-:::-""!~~..,..*
~*~~-* ___ Commission ;zt:"/'3,/0-/
C-..:z;_,;<--'7<
(Inspector's Signature)
{National Board Number and Endorsement)
Date qb"¢z5 (07/15)
Examination Category and Item Number C-C Item C3.30 R-A MRP-192 FORM OAR-1 OWNER'S ACTIVITY REPORT (Cont'd)
Table 1 Items With Flaws or Relevant Conditions That Required Evaluation for Continued Service Item and Flaw or Relevant Condition Evaluation Description Description Rounded indications identified when ETE-VC-2024-0052-CR1270992 performing a PT exam on the Charging The indications were determined not to be Pump Integral Support Welds service-induced and therefore are not subject to the applicable acceptance standards of IWC. The indications were evaluated and determined to meet the design requirements of the original construction code.
RHR Mixing Tee Welds CR1273151 2-2522A-13, pipe to tee weld 2-2522A-14, tee to pipe weld Conventional UT revealed no changes in the Re-examination of locations evaluated indications. The welds were also evaluated with during previous refueling outage. Weld phased array UT. The evaluation of the PAUT 13 exhibited linear indications in a data concluded that the volume examined previous outage and weld 14 had a contained no evidence of thermal fatigue prominent linear indication with planar cracking. These indications displayed no through-characteristics.
wall depth and were evaluated as ID surface roughness.
Table 2 Abstract of Repair/Replacement Activities Required for Continued Service Code Class Item Description Description of Work Date Repair/Replacement Completed Plan Number None None None None None
VIRGIL C. SUMMER NUCLEAR STATION (VCSNS} Unit 1 DOCKET NO. 50-395 OPERATING LICENSE NO. NPF-12 ENCLOSURE 2 CONTAINMENT INSERVICE INSPECTION-2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT Serial No.25-027
CONTAINMENT INSERVICE INSPECTION - 2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT CONTAINMENT INSERVICE INSPECTION - 2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL VIRGIL C. SUMMER NUCLEAR STATION RESPONSIBLE ENGINEER EVALUATION REPORT November 11, 2024 Prepared By:
Shawn P. Sweigart, P.E.
IWE / IWL Responsible Engineer Page 1 of 10
CONTAINMENT INSERVICE INSPECTION - 2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT Table of Contents 1
INTRODUCTION.............................................................................................................. 3 2
SCOPE............................................................................................................................. 3 3
INSPECTION PERSONNEL............................................................................................ 4 4
IWE / IWL INSPECTIONS................................................................................................ 4 5
INSPECTION PHILOSOPHY........................................................................................... 4 6
RESPONSIBLE ENGINEER EVALUATION..................................................................... 4 6.1 IWE Evaluation........................................................................................................................ 4 6.1.1 IWE Augmented Examinations.............................................................................................. 5 6.1.2 Other IWE Inspection Results............................................................................................... 7 6.1.3 IWE Reportable Conditions.................................................................................................... 7 6.1.4 IWE Reportable Conditions Requiring Augmented Examination....................................... 7 6.2 IWL Evaluation........................................................................................................................ 8 6.2.1 IWL Augmented Examination................................................................................................ 8 6.2.2 IWL Prestress Tendon System Evaluation........................................................................... 9 6.2.3 IWL Containment Exterior Concrete Surfaces..................................................................... 9 6.2.4 IWL Reportable Conditions.................................................................................................... 9 6.2.5 IWL Reportable Conditions Requiring Augmented Examination...................................... 9 7
SUMMARY
AND CONCLUSIONS................................................................................. 10 Page 2 of 10
CONTAINMENT INSERVICE INSPECTION-2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT 1
INTRODUCTION This report evaluates the Containment In-service Inspections which were conducted in accordance with the requirements of 1 0CFR50.55a paragraphs (g)(4), (b)(2)(viii), and (b)(2)(ix) at the Virgil C. Summer Nuclear Station (VCSNS) during the period of September through October 2024.
2 SCOPE The Containment In-service Inspection (GISI) Program Plan (ISE-4) details the requirements for the examination and testing of ASME Section XI Class MC and Class CC components at the VC Summer Nuclear Station (VCSNS). This Program Plan was developed in accordance with the requirements of the 2007 Edition (with Addenda through 2008) of the ASME Boiler and Pressure Vessel Code,Section XI, Division 1, Subsections IWE and IWL, as modified by NRC final rulemaking to 10 CFR 50.55a published in the Federal Register on November 5, 2014.
This Program Plan was developed using the guidance of "Containment Inspection Program Guide, (ASME Section XI, Subsections IWE and IWL)", EPRI document GC-110698.
The components subject to ASME Section XI, Subsection IWE and IWL requirements are those that make up the containment structure, its leak-tight barrier (including integral attachments),
and those that contribute to its structural integrity.
Specifically included are Class MC pressure retaining components and their integral attachments, (including metallic shell and penetration liners of Class CC pressure retaining components and their integral attachments), per IWE-1100; and Class CC reinforced concrete containments and post-tensioning systems, per IWL-1100.
The terms "Class MC" and "Class CC" are used in Section XI to identify components which meet the functional definitions in IWE-1100 and IWL-1100; however, these terms should not be equated with components and items that are designed per ASME Section 111, Class MC and Class CC requirements. Typically, the scope of components and items subject to ASME Section Ill for Class MC containment vessels and Class CC pre-stressed and reinforced concrete containments extends beyond that of ASME Section XI, Subsections IWE and IWL.
This Program Plan is effective from January 1, 2017, to December 31, 2026, for Subsection IWE and Subsection IWL activities. IWE and IWL inspections will be performed according to the schedules shown on Table 4.1.2.4-1 and Table 4.2.2.4-1 of ISE-4, respectively.
This report includes Period 3 IWE and IWL Inspections performed during the planned refueling outage (RF-28) in the fall of 2024.
The scope of inspection was in accordance with the ISE-4 RF-28 Outage Plan for Interval 3, Period 3 and included the following component inspections identified in ISE-4 and shown on the ISi drawings listed in ISE-4, Appendix A:
Containment Liner, Penetrations, Penetration Bolting, and Sumps Hatches, Transfer Tube, and Airlocks Containment Moisture Barrier at EL. 412' Reactor Building (Augmented)
Valve Chambers and Guard Pipes for RHR and RB Spray at EL. 397' Auxiliary Building (Augmented)
Concrete Tendon Access Gallery (General and Augmented)
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CONTAINMENT INSERVICE INSPECTION-2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT Liner transition and bottom leak chase test connections.
The Surveillance Test Procedure STP-803.006, "IWE and IWL Visual Examination" defines the requirements for the Visual Examinations in accordance with ASME Section XI for IWE and IWL.
Design Guideline ST-07, "Containment In-service Inspection Evaluation Criteria", was also developed to support this program and provides Engineering Services personnel the inspection criteria used to identify degradation mechanisms requiring documentation as "Recordable Indications". Also included are descriptions of suspect conditions which require evaluation and resolution by the Responsible Engineer.
3 INSPECTION PERSONNEL IWE inspections were conducted by or under the supervision of the ISi-NOE Containment In-service Inspection (CISI) Coordinator, J. Hamilton. Each inspector has been qualified to the requirements of the VCSNS CISI Program Plan, ISE-4.
The IWE/ IWL Responsible Engineer, Shawn Sweigart has BS and MS Degrees in Civil Engineering, with 14 years of experience in the design/construction of nuclear fuel plants and nuclear power plants and five years at VC Summer Nuclear Power Station. The Responsible Engineer is qualified to DQR-PGM-ISI-VC-CTMT and is a Registered Professional Engineer in the State of South Carolina (License Number 31145).
4 IWE / IWL INSPECTIONS The 2024 IWE and IWL inspections were conducted as an ongoing assessment of the condition of the Reactor Building (i.e., containment) structure. The RF-28 IWE/ IWL inspections were started in September 2024 and completed in October 2024.
5 INSPECTION PHILOSOPHY The 2024 inspections are part of an ongoing assessment of VCSNS programs which ensure compliance with ASME Section XI Subsections IWE and IWL. Previous inspections have identified areas for augmented examination. The augmented examinations were conducted to determine whether continued degradation had occurred, the extent of the continued degradation, and/or if the degradation had stabilized relative to the results of the previous inspection.
6 RESPONSIBLE ENGINEER EVALUATION Based on the inspections and examinations performed during RF-28, no conditions have been identified by the Responsible Engineer evaluation which are considered to be abnormal degradation or of significance to structural function. Additionally, no new conditions which exceeded the STP-803.006 threshold criteria (i.e., likely to experience accelerated degradation or aging) were identified during this evaluation.
6.1 IWE Evaluation Visual examinations of scheduled IWE components are performed, either directly or remotely, by line of site from available permanent vantage points. Remote viewing equipment (binoculars, cameras, etc.) are utilized where appropriate.
RF-28 IWE inspections include both General Visual and VT-1 examinations performed by Page 4 of 10
CONTAINMENT INSERVICE INSPECTION-2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT qualified inspectors under the direction of CISI Coordinator.
6.1.1 IWE Augmented Examinations Augmented Examination of the following components have been conducted since damage/
degradation was identified during the IWE baseline inspections of 2000 (RF-12). The RF-28 Augmented Examinations included issues identified during previous IWE inspections, specifically:
Containment Moisture Barrier Integrity RHR and Reactor Building Spray Penetration Guard Pipes Containment Moisture Barrier Integrity All accessible areas of the Containment Moisture Barrier, between the perimeter of the basement floor slab at Elevation 412' and the Containment Liner, were examined by VT-1 during RF-28. The moisture barrier seals the small gap between the perimeter of the concrete floor slab and the containment steel liner plate. This sealant joint has been subject to inspections and maintenance over the years because it has been observed that minor degradation has occurred at the sealant detail along with some light rusting in localized areas of the RB liner plate (typically where the sealant loses adhesion to the liner).
Additionally, the Containment Moisture Barrier has been the subject of NRC Information Notice 2004-09, "Corrosion of Steel Containment and Containment Liner", because typical minor degradation in the sealant and minor rusting on the adjacent liner has been identified at a number of operating nuclear facilities.
None of the inspection findings documented at VCSNS have reduced the capability of the RB liner plate to perform the required design basis function under required loads and conditions.
Containment Moisture Barrier examinations are performed in accordance with the ISE-4 plan and specifically the ASME Code for IWE, Table IWE-2500-1.
The Augmented Examination of the Containment Moisture Barrier performed during RF-28 identified two (2) locations where the seal had separated from the liner. All examinations were performed under Work Order 88201698445-40, with degradation documented in CR1271502.
The noted locations were reworked under Work Order 882017 48384.
Note that similar observations have been identified during most IWE inspections of the Containment Moisture Barrier since the IWE baseline inspections of 2000. In each case, necessary maintenance actions were taken to rework the seal and return the identified locations to design requirements.
Augmented Examinations will continue during future refueling outages to monitor the Containment Moisture Barrier integrity and ensure fulfillment of its design function; protecting the liner from potential corrosion in areas inaccessible to direct visual examination.
RHR and Reactor Building Spray Guard Pipes The Augmented Examination of the RHR and RB Spray Guard Pipes continues to monitor the issue first identified during the IWE baseline inspections of 2000 (RF-12). Groundwater leaks into the annulus space between the sump guard piping and the surrounding concrete wall pipe sleeve, resulting in degradation of the guard pipe coating and subsequently the exterior carbon steel surface.
The RF-28 Augmented Examination of the "A" Train RHR and RB Spray sump penetration Page 5 of 10
CONTAINMENT INSERVICE INSPECTION - 2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT (XRP0327 & XRP0329) guard pipes found relatively dry conditions with only minor ground water intrusion and moisture observed. Minor rust staining, likely primarily from the penetration sleeve, was observed on the coated surfaces. Additionally, spots of light rust were observed at localized poorly coated areas. CR1273293 was written to document the observed conditions.
Work orders 88201696801 and 88201695374 have been created to re-coat the degraded and suspect areas.
The RF-28 Augmented Examination of the "8" Train RHR and RB Spray sump penetration (XRP0328 & XRP0425) guard pipes found continued ground water intrusion with minor progression of coating degradation and corrosion. Corrosion staining was observed on both guard pipes while small spots of corrosion were observed on XRP0425 at localized poorly coated areas. CR 1273293 was created to document the observed conditions and track update of minimum wall thickness projections. ETE-VC-2024-0056 was created to document minimum guard pipe wall thickness projections. The evaluation concluded that the pipe wall thickness would be sufficient through Cycle 29 and beyond.
Note that CR-06-03337, CR-11-03206, CR-12-05536, CR-14-02439, CR-15-05594, CR 02004, CR-18-05192, CR-20-01583, and CR1226210 have documented similar observations during previous IWE inspections of the RHR and RB Spray guard piping.
Augmented Examinations will continue during future refueling outages to monitor the condition of the guard piping and ensure fulfillment of design function, providing containment integrity under required loads and conditions.
Historical Background on Guard Pipes The exterior surface of the four carbon steel guard pipes within each penetration sleeve were cleaned, prepared, and recoated during RF-20 (2012). The degraded surface of each guard pipe was visually inspected by borescope prior to and after recoating. Borescope inspections were performed during subsequent RF-21, RF-22, and RF-23 outages.
During RF-24, the Augmented Examination of the RHR and RB Spray guard pipes found that the "B" Train RHR and RB Spray sump penetrations (XRP0425, XRP0328) exhibited the greatest quantity of groundwater in-leakage and therefore an elevated degree of coating degradation and observable corrosion. Penetrations associated with the "A" Train RHR and RB Spray piping (XRP0329, XRP0327) were relatively dry with minimal areas of observable corrosion.
Condition Report CR-18-05192 was generated to document rust, pitting, and mineral deposits observed on inaccessible areas of the "B" RHR (XPR0425) guard pipe. Pipe wall thickness readings were obtained using Ultrasonic Testing on the subject carbon steel pipe to support the ES-120 Operability Recommendation. Reference Simpson/Russell TWR dated 11/17/2018 which evaluates the current XRP0425 guard pipe wall thickness and the projected thickness at the end of the next operating cycle.
During RF-25, the Augmented Examination of the RHR and RB Spray guard pipes found conditions similar to those found in RF-24. The "B" Train RHR and RB Spray sump penetrations (XRP0425, XRP0328) exhibited the greatest quantity of groundwater in-leakage and therefore an elevated degree of coating degradation and observable corrosion.
Penetrations associated with the "A" Train RHR and RB Spray piping (XRP0329, XRP0327) were relatively dry with minimal areas of observable corrosion. Condition report CR-20-01583 was generated to document the continued groundwater intrusions and subsequent coating degradation and corrosion. Calculations performed in Technical Work Record (TWR) JG40733 Page 6 of 10
CONTAINMENT INSERVICE INSPECTION-2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT attached to this condition report (CR) show that the condition would not cause pipe wall thinning in excess of established acceptable limits during the next cycle.
The exterior surface of the four carbon steel guard pipes within each penetration sleeve were cleaned, prepared, and recoated during and prior to RF-26 (fall 2021) under WO1605575. The augmented inspections of the guard pipes found areas that were missed during the recoating activities (documented in CR-21-02939). Some of these areas appeared to have intact coatings from previous coating applications. Other areas had been cleaned to the steel pipe surface.
The guard pipes, including the uncoated areas, did not show signs of corrosion or other degradation since the cleaning and recoating activities were performed. Maintenance worked with the remote visual NOE crew to recoat the identified areas.
6.1.2 Other IWE Inspection Results Degraded Coatings No new coating degradation exceeding acceptance standards was identified during the RF-28 IWE examinations. The inspections for RB degraded coatings for the unquailed coatings program were tracked under CR1270070. Degraded coatings identified were documented under various conditions reports referenced in this tracking CR.
Pressure Test Connections to Liner Leak Chases Examination of the Liner Leak Chase Pressure Test Connections closure plugs were performed in RF-28. Both the transition area liner test connections as well as the bottom liner test connections were inspected. Test connection with accessible pipe closure plugs were inspected to ensure the plugs remained installed. Junction box cover plates of test connections previously sealed and made inaccessible by encapsulation in epoxy grout were inspected to ensure no degradation or tampering of cover plates had occurred. No missing plugs or degraded/damaged junction box covers were identified during the inspections and all inspection conditions were reported satisfactory.
6.1.3 IWE Reportable Conditions In accordance with evaluation criteria provided in STP-803.006, no Recordable Indications of flaws or areas of abnormal degradation were identified during the RF-28 (2024) IWE Inspections.
6.1.4 IWE Reportable Conditions Requiring Augmented Examination None of the results of the IWE inspections were found to exceed the evaluation criteria of STP-803.006 or determined to be of concern that could potentially progress to an unacceptable structural condition prior to the next regularly scheduled IWE surveillance.
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CONTAINMENT INSERVICE INSPECTION-2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT 6.2 IWL Evaluation Visual examinations of scheduled IWL concrete components are performed directly or remotely, with adequate illumination, by qualified personnel with visual acuity sufficient to detect evidence of degradation. Remote viewing equipment (binoculars, borescopes, cameras, etc.) are utilized where appropriate.
The RF-28 IWL augmented examination of the tendon access gallery was performed by VCSNS CISI Responsible Engineer Shawn Sweigart and Senior NOE Inspector Ben Newman.
6.2.1 IWL Augmented Examination Augmented Examination of the Tendon Access Gallery (TAG) has been conducted since flaws/
degradation were identified during the IWL baseline inspections of 2000 (RF-12). The RF-28 Augmented Examinations included issues identified during previous IWL inspections, specifically:
Corrosion build-up and leaching on the outer TAG wall near the location of Tendon V-15 (Ref. WO 88101049980).
General Visual of TAG concrete (Ref. WO 88101050005).
Follow up inspection the V-113 bottom end CPM leakage originally documented in CR1223243 in (RF-27, Spring 2023).
Corrosion Build-Up Corrosion build-up near Tendon V-15 was inspected and determined to be mostly unchanged and comparable with previous observations made during the RF-25 to RF-27 inspections. See Figures 3 and 4 in the TAG Inspection Report attached to WO 88201698439 for comparison.
This type of corrosion remains limited to a single location. It is thought that the corrosion is due to groundwater in-leakage through a shrinkage crack in the tendon gallery exterior retaining wall causing corrosion of embedded metal (potentially a reinforcing bar).
The impact of this localized corrosion on the capability of the retaining wall to perform its structural design function is insignificant. It should be noted that the retaining wall is not a part of the containment structure but has been conservatively included in the IWL inspection scope boundary.
General Visual Examination During RF-28, the entire Tendon Access Gallery was inspected for groundwater in-leakage and concrete leaching. Water intrusion remains minimal with only a few areas exhibiting a wet surface. The extent of concrete leaching is comparable to previous inspections and evaluated as acceptable per CR-00-00988, CR-09-03667, and CR-21-04283.
Other observations from the TAG General Visual Examination included:
Only minor traces of grease seepage were observed from a few vertical tendon end caps other than V-113 (see below). Theses quantities were insignificant and do not represent any degradation of the tendon corrosion protection system.
Housekeeping was found to be acceptable.
Floor sumps were clear of any debris which could impede drainage.
The accumulation of calcium deposits on the floor noted at several locations during Page 8 of 10
CONTAINMENT INSERVICE INSPECTION-2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT the RF-26 inspection showed no significant changes with slight progression at the 135° azimuth. See Figures 1-2 of TAG Inspection Report attached to WO 88201698439 for comparison.
V-113 Bottom End CPM Leakage Follow-Up Continued corrosion protection medium (CPM or grease) leakage was observed on and below tendon V-113 and was documented in CR1270645. This condition was originally found and documented in CR1223243 in Spring 2023. The leakage is coming from between the tendon grease can and embedded bearing plate, likely from a gap/defect in the gasket. There is no indication of CPM leakage through a breach in the tendon conduit into and through the concrete. There are no signs of damage or degradation to the tendon end grease can that would indicate damage to the tendon end prestressing hardware. The leakage rate appears to be relatively consistent and does not show signs of accelerating. The worst case leakage rate determined in the Tendon Access Gallery Inspection Report (WO 88201698439) shows total leakage volume at the 45-year (spring of 2026) and 50-year (fall of 2030) IWL exams will be much less than the acceptance criteria limit. This identified CPM leakage does not represent a condition expected to cause degradation to the tendon hardware or impact function of the containment post tensioning system. CA 1297 4982 was created to update the ISE-4 Program Plan to add augmented inspection of the tendon V-113 grease leakage until it is repaired.
6.2.2 IWL Prestress Tendon System Evaluation No surveillances of the prestress tendon systems were scheduled or performed during RF-28.
The next tendon surveillance is scheduled for the Spring of 2026 (RF-29) for the 45-year examination. Note that Alternative Request RR-24-123 was submitted to the NRC in 2024.
Should this alternative request be approved, only concrete visual examinations, as enhanced by the alternative request, would be performed during RF-29. Should this occur, the next post tensioning system examination would be performed in 2030 (RF-32), for the 50-year examination.
6.2.3 IWL Containment Exterior Concrete Surfaces No surveillances of the containment exterior concrete surfaces were scheduled or performed during RF-28. The next concrete surface inspection is scheduled for the Spring of 2026 (RF-29) for the 45-year examination.
6.2.4 IWL Reportable Conditions In accordance with evaluation criteria provided in STP-803.006, no Recordable Indications of concrete deterioration or distress, such as described in ACI 201.1 and ACI 349.3R, were identified during the RF-28 (2024) IWL Inspections of the Tendon Access Gallery.
6.2.5 IWL Reportable Conditions Requiring Augmented Examination None of the results of the IWL inspection were found to exceed the evaluation criteria of STP-803.006 or determined to be of concern that could potentially progress to an unacceptable structural condition prior to the next regularly scheduled IWL surveillance.
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CONTAINMENT INSERVICE INSPECTION-2024 (RF-28)
ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT 7
SUMMARY
AND CONCLUSIONS The ASME Section XI IWE/IWL inspections performed concurrent with RF-28 (Oct.-Nov. 2024) are the continuation of the ongoing required inspections of the containment structure. These inspections provide the necessary basis for comparison with future surveillance results.
There were no reportable findings during the IWE inspections. All minor findings relating to coatings and moisture barrier were reviewed by the Responsible Engineer and found to be acceptable with no impact on the capability of the Reactor Building to meet its required license basis design functions.
Localized concrete surfaces of the Tendon Access Gallery displayed evidence of minor groundwater in leakage and efflorescence. These conditions were essentially unchanged, when compared to the previous RF-26 observations. Tendon grease accumulations at tendon V-113 were evaluated and determined to not represent tendon degradation. Addition of this condition to the augmented inspection list is being tracked via CA12974982. None of the IWL observed concrete conditions were judged to adversely impact performance or design function.
The RF-28 Augmented Examination of the Containment Moisture Barrier identified two (2) locations where the sealant had separated from the adjacent structure. CR 1271502 documents this degradation, which is similar to that found in previous moisture barrier inspections.
Localized sections of the sealant were reworked/inspected to restore the design function of the Containment Moisture Barrier.
Guard piping associated with the RHR and Reactor Building Spray sump penetrations continue to be susceptible to corrosion, exacerbated by the in-leakage of groundwater. The RF-28 Augmented Examination resulted in CR1273293 documenting rust staining, light surface rust, and continued water intrusion in the penetrations. ETE-VC-2024-0056 was created to document minimum guard pipe wall thickness projections. These wall thickness projections confirm the structural integrity of the guard pipes through cycle 29. Work orders have been created to repair the degraded/deficient coating areas on guard pipes (88201696801, 88201695374, 88201696802, & 88201696803).
The following areas shall remain on the STP-803.006 Augmented Examination list, for performance during subsequent refueling outages to ensure that any structural degradation will continue to be examined and evaluated in compliance with the plant design basis.
IWE - Containment Moisture Barrier Integrity IWE - Guard Pipes Corrosion IWL - Tendon Access Gallery Corrosion CA12974982 has been created to add augmented inspection of the tendon V-113 CPM leakage into the ISE-4 program plant. The inspection of the Tendon Access Gallery for concrete leaching and general housekeeping will continue as General Visual Examinations under the ASME Section XI IWE/IWL program to be performed along with the Augmented Examination during each Refueling Outage. Though the conditions inspected as part of the augmented inspection of the Tendon Access Gallery were found to be essentially unchanged, these augmented inspections will conservatively continue during the next refueling outage.
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