ML20212L587
| ML20212L587 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 07/30/2020 |
| From: | Lippard G Dominion Energy Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 20-232 | |
| Download: ML20212L587 (19) | |
Text
V. C. Summer Nuclear Station Bradham Blvd & Hwy 215. Jenkinsville. SC 29065 Mailing Address:
P.O. Box 88, Jenkinsville, SC 29065 Dominion Energy.com Attn: Document Control Desk U. S. Nuclear Regulatory Commission Washington, DC 20555-0001 July 30, 2020 VIRGIL C. SUMMER NUCLEAR STATION (VCSNS) UNIT 1 P
Dominion
- =I Energy Serial No.20-232 VCS-LIC/BB RO Docket No. 50-395 License No. NPF-12 INSERVICE INSPECTION (ISi) OWNER'S ACTIVITY REPORT (OAR) FOR REFUELING OUTAGE 25 Enclosed is the lnservice Inspection (ISi) Owner's Activity Report (OAR) covering ISi activities associated with the second outage of the second period of the fourth ISi interval (Enclosure 1) and the Containment lnservice Inspection (CISI) Responsible Engineer Evaluation Report associated with the first outage of the second period of the third CISI interval (Enclosure 2).
This report is submitted pursuant to the American Society of Mechanical Engineers (ASME)
Boiler and Pressure Vessel Code (2007 Edition through 2008 Addenda),Section XI, Rules for lnservice Inspection of Nuclear Power Plant Components, Article IWA-6000, Records and Reports, and ASME Code Case N-532-5, Repair/Replacement Activity Documentation Requirements and lnservice Summary Report Preparation and Submission,Section XI, Division 1.
Should you have any questions, please call Michael S. Moore at (803) 345-4752.
Sincerely, George Lippard Site Vice President V.C. Summer Nuclear Station Commitments contained in this letter: None
Enclosures:
- 1) lnservice Inspection Owner's Activity Report for Refuel 25, Report Number 24
- 2) Containment lnservice Inspection - 2020 ASME Section XI, Subsections IWE and IWL Responsible Engineer Evaluation Report.
cc:
G. J. Lindamood - Santee Cooper L. Dudes - NRC Region II V. Thomas-NRC Project Mgr.
NRC Resident Inspector Serial No.20-232 Docket No. 50-395 RF 25 Owner's Activity Report : Page 1 of 6 lnservice Inspection Owner's Activity Report For Refuel Outage 25, Report Number 24
FORM OAR-1 OWNER'S ACTIVITY REPORT ReportNumber _____________
1_N_S_ER_v_1_c_E_IN_S_P_E_C_T_1o_N_R_E_P_O_R_T_#2_4 ____________ _
Plant _________
v_c_s_U_M_M_E_R_N_u_c_L_EA_R_S_T_AT_l_O_N_, _PO_B_o_x_s_s_. J_E_N_K_IN_S_V_IL_L_E_. _sc_2_90_6_5 ________
Unit No. ____
-,-_U_N=--IT....,1 ______ Commercial service date ___
JAN U_A_R_Y_1_* _1_98_4 __ Refueling outage no. __
R_F-_2_5 __
{if applicable)
Applicable inspection interval _______________
1....,s,.,.1_--::ln,...t..,.erv...,,.a:-l4~; C.....,1S,_1...,*_ln_t_e_rv_a_l_3 ______________ _
(1st, 2nd, 3rd, 4th, other)
Applicable inspection period _______________
IS_l_-..,.P_e_ri_o_d_2_;.,..c_1s_1_-_P_e_ri_od_2 _____________ _
(1st, 2nd, 3rd)
Edition and Addenda of Section XI applicable to the inspection plans _______
2_0_07_E_d_iti_o_n_th_r_o_ug_h_20_0_8_A_d_d_e_nd_a _____ _
Date and revision of inspection plans ______
IS_I -_F_e_b_r_u_ary_2_4_,_2_0_2o_R_e_v_is_io_n_2A_;_C_l_S_I -_A_p_r_il_4_, _20_1_B_R_ev_i_si_o_n_3_B _____ _
Edition and Addenda of Section XI applicable to repair/replacement activities, if different than the inspection plans NIA Code Cases used for inspection and evaluation: _____________
N_-5_3_2_-_5_, N_-6_5_3_-_1,_N_-_77_0_-2 ___________ _
(if applicable)
CERTIACATE OF CONFORMANCE I certify that (a) the statements made in this report are correct; (bl 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 _____
,__R_F_-_25 ______ conform to the requirements of the ASME Code,Section XI.
(refueling outage number)
Marissa J. Post ::===.."::::..m"'
Signed, __________
_=_*u_"_lt_~<<_~ ______
1s_1_P_r_o_g_ra_m_0wn
__ e_r _____ Date ________
7_-7_-_2_0_2_0 _______ _
(Owner or Owner's Designee. Title}
CERTIFICATE OF INSERVICE INSPECTION I, the undersigned, holding a valid commission issued by the National Board of Boiler and Pressure Vessel Inspectors and employed by Hartford Steam Boiler Inspection & Insurance Company of HARTFORD, CT 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 any kind arising from or connected with this inspection.
_ _.,,,.??'--~--xJ._.
....,~=;,;;,-'--~------ commission ----------N_B#-1_31....,.o,,_4....,A_l-_IS_C....,1N_R _________ _
(Inspector's Signature)
!National Board Number and Endorsement)
(07/15)
FORM OAR-1 OWNER'S ACTIVITY REPORT (Cont'd)
Table 1 Items With Flaws or Relevant Conditions That Required Evaluation for Continued Service Examination Category Item Description Evaluation Description and Item Number F-A MK-EFH-0119 Rotated pipe clamp out of tolerance. Evaluation of pipe clamp at F1.10B Rigid Support the measured angular position determined the as-found support was capable of performing its design basis function. Support reworked. CR-20-01306 F-A MK-RHH-0133 Rotated pipe clamp out of tolerance; Loose jam nut. Evaluation F1.108 Rigid Support of pipe clamp at the measured angular position determined the as-found support was capable of performing its design basis function. Loose jam nuts do not affect the support's capability to perform its intended design basis function. Support reworked.
CR-20-01375 Page 2 of 5
FORM OAR-1 OWNER'S ACTIVITY REPORT (Cont'd)
Table 2 Abstract of Repair/Replacement Activities Required for Continued Service Code Class Item Description Description of Work Date Repair/Replacement Completed Plan Number 1
MK-CSH-0924 Replaced snubber.
11/11/2019 1916966 Snubber CR-19-04022 1
MK-RHH-0263 Replaced snubber.
11/13/2019 1916968 Snubber CR-19-04021 1
MK-RHH-0173 Replaced snubber.
11/14/2019 1916967 Snubber CR-19-04020 1
XVC08993A-SI Repaired valve.
11/12/2019 1916908 A Loop High Head Hot CR-19-03971 Leg Header Check Valve 1
XSG0002A Replaced inspection port 4/23/2020 1915837 A Steam Generator wrapper locknuts.
1 XSG0002B Replaced inspection port 4/23/2020 1915838 8 Steam Generator wrapper locknuts.
1 XSG0002C Replaced inspection port 4/23/2020 1915840 C Steam Generator wrapper locknuts.
1 XSG0002A Plugged both ends of three (3) 512712020 1915904 A Steam Generator A Steam Generator tubes.
CR-20-01405 1
XSG0002B Plugged both ends of one (1) 5/27/2020 1915905 B Steam Generator B Steam Generator tube.
CR-20-01431 2
MK-MUH-1043 Reworked support.
10/22/2019 1811323 Pipe Support CR-18-02081 2
XVT08147-CS Reassembled valve after 4/22/2020 1818759 Alternate Charging disassembly and inspection.
Header Isolation Valve CR-18-05063 2
XVC08103-CS Replaced valve disc.
4/23/2020 1901492 RCP Seal Return Isolation Bypass Check Valve 2
MK-EFH-0119 Reworked support.
412512020 1818154 Rigid Support CR-20-01306 2
MK-RHH-0133 Reworked support.
6/2/2020 2005478 Rigid Support CR-20-01375 3
XPP0039A Rebuilt pump.
2/11/2019 1709218 A Service Water Pump Page 3 of 5
FORM OAR-1 OWNER'S ACTIVITY REPORT (Cont'd)
Table 2 (Cont'd)
Abstract of Repair/Replacement Activities Required for Continued Service Code Class Item Description Description of Work Date Repair/Replacement Completed Plan Number 3
A Service Water pipe Replaced pipe elbow.
2/13/2019 1904112 elbow CR-19-00368 3
XPP0004B Replaced a-rings.
4/10/2019 1809481 Diesel Generator Fuel Oil CR-018-01441 Transfer Pump 48 3
XVC03120A-SW Replaced valve disc.
4/23/2019 1702449 A Diesel Generator Cooler CR-17-00947 FS Supply Header Check Valve 3
B Diesel Generator Replaced rain hood.
5/6/2019 0904235 Muffler piping rain hood CR-09-00791 3
A Diesel Generator Replaced rain hood.
5/8/2019 0904238 Muffler piping rain hood CR-09-00791 3
XVG03113B-SW Replaced valve disc.
517/2019 1813932 B SW Screen Wash CR-19-01681 Isolation Valve 3
XHE0017A-HE1 Replaced tube bundle.
5/21/2019 1702673 A Diesel Generator CR-14-01289 Lube Oil Cooler Hx 3
XHE0017 A-HE2 Replaced tube bundle.
5/21/2019 1702672 A Diesel Generator CR-14-01289 Jacket Water Cooler Hx 3
XHE0017A-HE3 Replaced tube bundle.
5/21/2019 1702671 A Diesel Generator CR-14-01289 lntercooler Hx 3
XVG03196-SW Replaced valve disc.
12/13/2019 1918790 XHX-1C Service Water CR-19-04386 & CR-19-04425 Outlet Bypass Header Discharge Isolation Valve 3
XVT03195C-SW Reassembled valve after 1/6/2020 1918775 XHX-1C Service Water disassembly and inspection.
Outlet Bypass Flow CR-19-04386 Control Valve 3
XVC06652-SF Reassembled valve after 1/29/2020 1911677 A Spent Fuel Cooling disassembly and inspection.
Pump Discharge Check Valve Page 4 of 5
FORM OAR-1 OWNER'S ACTIVITY REPORT (Cont'd)
Table 2 (Cont'd)
Abstract of Repair/Replacement Activities Required for Continued Service Code Class Item Description Description of Work Date Repair/Replacement Completed Plan Number 3
XVB-031238-SW Replaced flanges, tee, and 5/2/2020 1909664 CC Heat Exchanger B SW piping downstream of valve.
Return Valve Replaced valve. CR-20-01409 MC XSM0004A Reinstalled encapsulation 4/19/2020 1902923 A Chamber Reactor chamber. CR-20-01185 Building Recirculation Sump Page 5of5 Serial No.20-232 Docket No. 50-395 RF 25 Owner's Activity Report : Page 1 of 12 Containment lnservice lnspection-2020 ASME Section XI, Subsections IWE and IWL Responsible Engineer Evaluation Report
CONTAINMENT INSERVICE INSPECTION - 2020 ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT CONTAINMENT INSERVICE INSPECTION - 2020 ASME SECTION XI, SUBSECTIONS IWE AND IWL VIRGIL C. SUMMER NUCLEAR STATION RESPONSIBLE ENGINEER EVALUATION REPORT June 15, 2020 Prepared By:
Shawn P. Sweigart, P.E.
IWE/ IWL Responsible Engineer
CONTAINMENT INSERVICE INSPECTION - 2020 ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT Table of Contents
- 1. INTRODUCTION.......................................................................................................................... 1
- 2. SCOPE........................................................................................................................................ 1
- 3. INSPECTION PERSONNEL........................................................................................................ 2
- 4. IWE I IWL INSPECTIONS............................................................................................................ 2
- 5. INSPECTION PHILOSOPHY....................................................................................................... 2
- 6. RESPONSIBLE ENGINEER EVALUATION................................................................................ 2 6.1.
IWE EVALUATION...................................................................................................................... 2 6.1.1.
IWEAUGMENTED EXAMINATIONS............................................................................ 3 6.1.2.
OTHER IWE INSPECTION RE SUL TS.......................................................................... 5 6.1.3.
IWE REPORTABLE CONDITIONS................................................................................ 5 6.1.4.
IWE REPORTABLE CONDITIONS REQUIRING AUGMENTED EXAMINATION......... 5 6.2.
IWL EVALUATION....................................................................................................................... 6 6.2.1.
IWL AUGMENTED EXAMINATION............................................................................... 6 6.2.2.
IWL PRESTRESS TENDON SYSTEM EVALUATION.................................................. ?
6.2.3.
IWL CONTAINMENT EXTERIOR CONCRETE SURFACES........................................ 8 6.2.4.
IWL REPORTABLE CONDITIONS................................................................................ 8 6.2.5.
IWL REPORTABLE CONDITIONS REQUIRING AUGMENTED EXAMINATION........ 8
- 7.
SUMMARY
AND CONCLUSIONS............................................................................................... 9 Page i
CONTAINMENT INSERVICE INSPECTION - 2020 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 OCFR50.55a paragraphs (g)(4), (b)(2)(viii), and (b)(2)(ix) at the Virgil C. Summer Nuclear Station (VCSNS) during the period of March through May 2020.
- 2.
SCOPE The Containment In-service Inspection (CISI) 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 Ill, 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 2 IWE and IWL Inspections performed during the planned refueling outage (RF25) in the spring of 2020.
The scope of inspection was in accordance with the ISE-4 RF25 Outage Plan for Interval 3, Period 2 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, and Sumps Hatches, Transfer Tube, and Airlocks Containment Moisture Barrier at EL. 412' Reactor Building (Augmented)
Valve Chambers and Guard Pipes for "A" and "B" RHR and RB Spray at EL. 397' Auxiliary Building (Augmented)
Concrete Tendon Access Gallery (General and Augmented)
Containment Exterior Concrete Surfaces Prestress Tendon and Corrosion Protection Systems Page 1of9
CONTAINMENT INSERVICE INSPECTION-2020 ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT 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 Plant Support Engineering (PSE) 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 IWL prestress system tendon inspection, testing, and containment concrete examinations were performed by vendor (Precision Surveillance Corporation, East Chicago, IN) qualified inspection personnel using the vendors program and procedures. Vendor qualifications and procedures were reviewed and approved by the Owner, DESC, as meeting the V. C. Summer Station and Dominion Energy program requirements. Precision Surveillance Corporation has been performing the IWL examinations and tests for many years for the Virgil C. Summer Station containment.
IWL concrete augmented inspections in the tendon access gallery were performed by the IWE/
IWL Responsible Engineer, with assistance from the CISI Coordinate.
The IWE/ IWL Responsible Engineer, Shawn Sweigart has BS and MS Degrees in Civil Engineering, with nine years of experience in the design/construction of nuclear fuel plants and nuclear power plants and one year at VC Summer Nuclear Power Station. The Responsible Engineer is a Registered Professional Engineer in the State of South Carolina.
- 4.
IWE / IWL INSPECTIONS The 2020 IWE and IWL inspections were conducted as an ongoing assessment of the condition of the Reactor Building (i.e. containment) structure. The RF25 IWE/ IWL inspections were started in March 2020 and completed in May 2020.
- 5.
INSPECTION PHILOSOPHY The 2020 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 RF25, 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.
Page 2 of 9
CONTAINMENT INSERVICE INSPECTION - 2020 ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT RF25 IWE inspections include both General Visual and VT-1 examinations performed by qualified QC Inspectors under the direction of PSE CISI Coordinator, J. Hamilton.
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 (RF12). The RF25 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 RF25. 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 theASME CodeforlWE, Table IWE-2500-1.
The Augmented Examination of the Containment Moisture Barrier performed during RF25 identified eleven locations where the seal had separated from the liner. All examinations were performed underWork Order 1905140, with degradation documented in CR-20-01168. The noted locations were reworked under Work Order 1903516 and re-inspected. Re-inspection of the repaired areas found four of the repairs to be insufficient, partially due to work activities in the area causing accidental contact with the uncured moisture barrier. These insufficiently repaired areas were documented in CR-20-01395 and repaired under the original WO 1903516 and re-inspected again. During the reinspection, further damage to the moisture barrier from scaffold erection was identified in two locations. These areas were documented in CR-20-01440 and reworked under Work Order 2005512 and re-inspected. Minor surface rust was found in one area. As documented in CR-20-01440 Action 003, ultrasonic thickness measurements taken after surface prep and coating showed that the liner plate thickness in this area was within acceptable limits.
Note that CER-04-1517, CR-08-01993, CR-09-04879, CR-12-05160, CR-14-02363, CR 04864, CR-17-01976, and CR-18-04657 have documented similar observations during previous IWE inspections of the Containment Moisture Barrier. 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.
Page 3of9
CONTAINMENT INSERVICE INSPECTION - 2020 ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT 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 (RF12). 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.
It is noted that the exterior surface of the four carbon steel guard pipes within each penetration sleeve were cleaned, prepared, and recoated most recently during RF20 (2012). The degraded surface of each guard pipe was visually inspected by borescope prior to and after recoating.
Borescope inspections were performed during subsequent RF21, RF22, and RF23 outages.
During RF24, 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 RF25, the Augmented Examination of the RHR and RB Spray guard pipes found conditions similar to those found in RF24. 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 attached to this condition report show that the condition will not cause pipe wall thinning in excess of established acceptable limits during Cycle 26.
The guard piping associated with the RHR and RB Spray sump penetrations continue to be susceptible to corrosion, exacerbated by the in-leakage of site groundwater. To address potential impact on future plant operation, Work Order 1605575 has been generated to hydrolaze, prepare, and then recoat the degraded guard piping surfaces. This effort was scheduled in conjunction with, or prior to, RF25 refueling outage and involves construction of a mock-up to confirm preparation and application methods for applying two coats of PPG Amerlock 400 (reference attachment to CR-15-05594). However, due to significant rainfall in the months leading up to RF25 and significant groundwater intrusion, these repairs were delayed and are tentatively planned for Cycle 26.
Note that CR-06-03337, CR-11-03206, CR-12-05536, CR-14-02439, CR-15-05594, CR 02004, and CR-18-05192 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.
Page 4of9
CONTAINMENT INSERVICE INSPECTION - 2020 ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT 6.1.2. Other IWE Inspection Results Degraded Coatings Although there were several inspection findings that identified coating issues on IWE components, there were no findings that indicated actual, or potential, component degradation within the scope of the IWE inspection boundary.
IWE components with degraded coatings are identified below (via component number and condition report) along with a conservative estimate of loose coatings, if applicable. These items have been added to a running list (see CR-20-01268) of Reactor Building areas not meeting the requirements of Coating Service Level 1 (CSL 1 ). This tabulation is controlled by the ES-425 Cumulative Effects Program, which ensures that the quantity of unqualified RB coatings is within the evaluated design margin. Rework of these items is scheduled for RF26.
/WE Component Condition Report Degraded Coating RB Liner CR-20-01518 n/a XRP0403 CR-20-01521 4.00 SF XRP0401 CR-20-01529 n/a XRA0003 CR-20-01530 1.50 SF XRP0412 CR-20-01532 n/a XRP0308 CR-20-01533 0.25 SF XRP0202 CR-20-01534 XRA0002 CR-20-01538 n/a XRP0033 CR-20-01539 n/a XRP0218 CR-20-01540 0.25 SF XRP0203 CR-20-01541 XRP0211 CR-20-01542 0.25 SF
- Previously identified in CR-20-01242
- Previously identified in CR-17-01959 Pressure Test Connections to Liner Leak Chases During plant construction leak chase test canopies (consisting of channels or angle sections) were installed over containment liner plate seam welds that would be inaccessible to inspection following construction. The leak chases were used during construction to pressure test the welds for leaks during plant construction.
As discussed in the previous (RF23) IWE Inspection Report, the CR-17-02023 extent of condition inspection included the test connections for the six leak test zones in the lncore Instrumentation Chase. CR-17-02816 identified a missing pipe closure plug from the test connection for lncore Zone 6. Located in the ceiling and about 8 feet above the lncore pit floor, a new pipe plug was scheduled to be installed during the following refueling outage (RF24).
Replacement of the Zone 6 Leak Chase closure plug was completed during the RF23 refueling outage, via WO 1706298. No work was required during RF24 or later.
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 RF25 (2020) 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.
Page 5 of 9
CONTAINMENT INSERVICE INSPECTION-2020 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.
RF25 IWL augmented examination of the tendon access gallery were performed by Responsible Engineer S. Sweigart, with assistance from VCSNS PSE GISI Coordinator.
6.2.1. IWL Augmented Examination Augmented Examination of the Tendon Access Gallery (TAG) has been conducted since flaws/
degradation was identified during the IWL baseline inspections of 2000 (RF12). The RF25 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. STTS 1905137-002).
General Visual of TAG concrete (Ref. STTS 1905137-001).
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 RF24 (2018) inspection. 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 RF25, the entire Tendon Access Gallery was inspected for groundwater in-leakage and concrete leaching. Water intrusion remains minimal, with no indication of active water flow and only a few areas exhibiting a wet surface. This observation would imply that the extent of concrete leaching is comparable to previous inspections and evaluated as acceptable per CR-00-00988, CR-09-03667, and CR-12-04283.
Other observations from the TAG General Visual Examination included:
Only minor traces of grease seepage were observed from a few vertical tendon end caps.
The quantity was insignificant and did not represent any degradation of the tendon corrosion protection system.
Housekeeping was found to be acceptable. Minor accumulations of concrete debris were noted on the TAG floor.
Floor sumps were clear of any debris which could impede drainage.
It was noted during the walkdown that one of the sump pumps was continuously running and there appeared to be a material buildup in the float guide tube. CR-20-00724 was initiated to inspect and provide maintenance to ensure proper function of sump pump.
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CONTAINMENT INSERVICE INSPECTION-2020 ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT 6.2.2. IWL Prestress Tendon System Evaluation The Tenth Period Tendon Surveillance (401h year) was performed immediately prior to and during RF 25 between March and May 2020. The surveillance work activities were performed by Precision Surveillance Corporation (PSC) to approved vendor procedures that met the requirements of the V.C. Summer tendon inspection program documents including Engineering Services Specification SP-228," Surveillance of Reactor Building Post Tension System" and Surveillance Test Procedure STP-160.001, "Containment Tendon Test."
The complete details of the inspection including procedures, results, and conclusions are contained in the PSC Document REP-1156-51 O Rev. O "Final Report for the 401h Tendon Surveillance at V.C. Summer Nuclear Station." The report is on file with Surveillance Test Task Sheet STTS-1906250. The following is a summary of the inspection results.
Three tendons from each tendon group (vertical, dome, and hoop) were randomly selected for testing. The predicted liftoff forces were calculated for each tendon in accordance with the methodology of Regulatory Guide 1.35.1. The measured liftoff forces for all surveillance tendons were found to be above 95% of the predicted lift off force values as required by IWL-3221.1 (b).
The group average liftoff force for all as-found liftoff values as well as the individual liftoff values were all above the required average minimum design forces for the respective tendon group and are acceptable.
GROUP GROUP AVERAGE (KIPS)
MINIMUM DESIGN AVERAGE (KIPS)
Dome 1094.8 1063 Hoop 1108.6 1000 Vertical 1272.7 1160 The results of the regression analyses, performed in TWR SS-20-003 attached to W01906249, for each of the three tendon groups confirm that the minimum group average prestress will be available for each group through the period until the next tendon surveillance. The regression (trend) analysis results using the current as well as previous liftoff data show all groups forces staying above the required minimum design force beyond the next regularly scheduled surveillance (451h year).
Group Forecast Year at Which Prestress When Group Mean Will Fall Below DesiQn Minimum AveraQe Group Prestress Hoop After 2100 Vertical After 2100 Dome 2074 All of the other required surveillance and test criteria for the tendons including tendon force and elongation, wire samples inspection and testing, grease samples testing for water and impurities, tendon anchorage hardware and adjacent concrete areas, and corrosion protection grease were acceptable.
The following were identified and evaluated to be acceptable conditions not indicative of abnormal degradation nor needing additional augmented inspections:
The horizontal tendon H49CB selected for random surveillance was found upon removal of grease cap and cleaning of grease from anchorage with one wire protruding from the shop end. The projection was by a small amount of 0.1 O". The condition was evaluated and concluded to be Page 7 of 9
CONTAINMENT INSERVICE INSPECTION - 2020 ASME SECTION XI, SUBSECTIONS IWE AND IWL RESPONSIBLE ENGINEER EVALUATION REPORT acceptable by CR-20-01234.
Individual sample wire tensile testing from the one wire removed from each of the three detensioned tendons (one from each group) found that the strength for all wire samples tested exceeded the minimum specified ultimate strength 240 ksi and the corresponding wire elongation at failure exceeded the 4% minimum elongation required by the ASTM material specification for the high strength wire.
Summarizing, the surveillance and tests confirmed that the prestress tendon system and its corrosion protection system are performing the license basis design functions without indication of abnormal degradation and will continue to perform those functions through the next regularly schedule surveillance at the 45th year.
6.2.3. IWL Containment Exterior Concrete Surfaces The general visual inspection was performed by qualified PSC inspection personnel concurrent with the tendon system surveillance during RF 25. The scope included all accessible exterior concrete surfaces of the Reactor Building both above and below roof lines, the dome, and the ring girder. The inspections were performed in accordance with approved PSC procedures that met the requirements of the Owners program. The results of the inspection are documented in the PSC Document REP-1156-510 Rev. 0 "Final Report for the 401h Tendon Surveillance at V.C.
Summer Nuclear Station." The Inspection findings were minor and were assessed as minimal or no change observed from the previous surveillance performed concurrent with the 3Q1h year tendon surveillance. None of the inspection findings represented abnormal degradation of the concrete surface. Summarizing the concrete inspection for the containment exterior met the acceptance criteria and found the overall concrete in good condition demonstrating continued durability.
The concrete inspection was performed in accordance with STP-803.006 under work order 1905139.
6.2.4. IWL Reportable Conditions No reportable items or items indicative of abnormal degradation were identified by the IWL inspections for:
Augmented Inspection of the Tendon Access Gallery.
40lh Year surveillance of Prestress Tendon System.
General Visual examination of all exterior concrete surfaces of the containment structure performed concurrent with the Prestress Tendon System surveillance.
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 - 2020 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 RF25 (March-May 2020) 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 groundwater in-leakage and efflorescence. These conditions were essentially unchanged, when compared to the previous RF24 observations. None of the IWL observed concrete conditions were judged to adversely impact performance or design function.
The RF25 Augmented Examination of the Containment Moisture Barrier identified eleven locations where the sealant had separated from the adjacent structure. CR-20-01168 documents this degradation, which is similar to that found in previous 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 RF25 Augmented Examination resulted in CR-20-01583 documenting rust and coating degradation of penetration XRP0327, XRP0328, XRP0329, and XRP0425 guard pipes. Wall thickness calculations were performed to justify the ES-120 Operability Recommendation. Work Order 1605575 was previously generated to hydrolaze, prepare, and recoat degraded surfaces on all four guard pipes associated with the RHR and RB Spray sumps. As this work was not able to be performed prior to RF25, the work is tentatively planned for Cycle 26.
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 In addition, 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.
The IWL inspections performed during RF 22 in Fall 2015 included:
IWL-Prestress tendon system.
IWL - Reactor Building exterior concrete surfaces.
These IWL inspections performed at a 5-year inspection interval found that the containment structure is performing its design function as required and experiencing no abnormal degradation.
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