ML16021A080

Inservice Inspection Summary Report

ML16021A080
Person / Time
Site:	Braidwood
Issue date:	01/21/2016
From:	Marchionda M Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BW160006
Download: ML16021A080 (9)

Text

Exelon January 21, 2016 BW160006 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Unit 2 Facility Operating License No. NPF-77 NRC Docket No. STN 50-457 Exelon Generation Company Braidwood Station 35100 South Route 53, Suite 84 Braceville, 60407-9619 www.exeloncoro.com

Subject:

Braidwood Station, Unit 2 lnservice Inspection Summary Report Enclosed please find the post-outage summary report (i.e., 90 day report) for lnservice Inspection (ISi) examinations conducted during Braidwood Station, Unit 2 Refueling Outage 18 (A2R18). This report is submitted in accordance with the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, "Rules for the lnservice Inspection of Nuclear Power Plant Components," and ASME Code Case N-532-4, "Repair/Replacement Activity Documentation Requirements and lnservice Summary Report Preparation Submission

-Section XI, Division 1." Attachment 1 provides the Owner's Activity Report (OAR) for ISi activities conducted during A2R18 including a list of items with flaws or relevant conditions that required evaluation for continued service, and an abstract of repair/replacement activities required for continued service. In addition, Attachment 2 provides the results of Containment ISi activities performed in accordance with ASME Section XI, Subsection IWE, "Requirements for Class MC and Metallic Liners of Class CC Components of Light-Water Cooled Power Plants," and Subsection IWL, "Requirements of Class CC Components of Light-Water Cooled Power Plants," with specified modifications and limitations in 1 O CFR 50.55a, "Codes and standards." Please direct any questions you may have regarding this submittal to Mr. George Golwitzer, Regulatory Assurance Manager, at (815) 417-4571.

Marri Marchionda-Palmer Site Vice President Braidwood Station Attachments:

1. Owner's Activity Report (OAR) for A2R18 2. A2R18 Containment ISi (IWE/IWL)

Results cc: Regional Administrator

-NRC Region Ill NRC Senior Resident Inspector-Braidwood Station NRR Project Manager-Braidwood Station Illinois Emergency Management Agency -Division of Nuclear Safety ATTACHMENT 1 FORM OAR-1 OWNER'S ACTIVITY REPORT TABLE 1, ITEMS WITH FLAWS OR RELEVANT CONDITIONS THAT REQUIRED EVALUATION FOR CONTINUED SERVICE TABLE 2, ABSTRACT OF REPAIR/REPLACEMENT ACTIVITIES REQUIRED FOR CONTINUED SERVICE ATTACHMENT 1 FORM OAR-1 OWNER'S ACTIVITY REPORT Plant Braidwood Generating Station, 35100 South Route 53, Suite 84, Braceville, Illinois 60407 Unit No. 2 Commercial Service Date ___

___ Refueling Outage Number ---'-A"""'2""""R""1-"-8

__ (if applicable)

Current Inspection Interval Third Inspection Interval (ISI), Second Inspection Interval (Containment ISI) (l't, 2"d, 3ra, 4ffi, other) Current Inspection Period Second Inspection Period (ISI and Containment (l't, 2 '3id) Edition and Addenda of Section XI applicable to the Inspection Plans ASME Section XI 2001 Edition through 2003 Addenda Date I Revision of Inspection Plans August 5, 2014 (Revision 11), 9/25/2014 (Revision 12), January 26, 2015 (Revision

13) and August 21, 2015 (Revision

14) Edition and Addenda of Section XI applicable to repair/replacement activities, if different than the inspection plans Same as above Code Cases used: N-460, N-508-3, N-508-4, N-513-3, N-532-4, N-532-5, N-566-2, N-586-1, N-597-2, N-613-1, N-639, N-652-1, N-661-1, N-700 N-706-1, N-722-1, N-729-1, N-731, N-751 N-753 CERTIFICATE OF CONFORMANCE I certify that (a) the statements made in this report are correct; (b) the examinations and tests, meet the Inspection Plan as required by the ASME Code,Section XI; and (c) the repair/replacement activities and evaluations supporting the completion of A2R18 conform to the requirements of Section XI (refueling outage number) 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 The Harford Steam Boiler Inspection and Insurance Company of Connecticut of Hartford, Connecticut 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 Section XI. By signing this certificate neither the Inspector nor his employer makes any warranty expressed or implied concerning the repair/ replacement activities and evaluation described in this report. Furthermore, neither the Inspector nor his employer shall be liable in any manner for y personal injury or property damage or a loss of any kind arising from or connected with this inspection (3c/I/ A,//, I, C National Board, State, Province, and Endorsements Date Page 1 of 3 ATTACHMENT 1 TABLE 1 ITEMS WITH FLAWS OR RELEVANT CONDITIONS THAT REQUIRED EVALUATION FOR CONTINUED SERVICE Examination Examination Item Category Number Item Description Evaluation Description D-B 02.10 2DG5045A Pitting observed visually at valve body flange surface was evaluated under (IR 2463461 I EC 385798) D-B 02.10 2CV8444 Body-to-bonnet bolting evaluation completed under ATI 2430862-02 C-H C7.10 2CV8146 Body-to-bonnet bolting evaluation completed under ATI 2566190-02 C-H C7.10 2Sl8808C Body-to-bonnet bolting evaluation completed under ATI 2566198-02 C-H C7.10 2CV8123 Inlet flange bolting evaluation BRW201516203 under WO 1723403-01 B-P B15.10 2RC8001B Bonnet leak off line downgraded from Class 1 to Non-Safety Related under EC 403668 B-P B15.10 2RC8037A Body-to-bonnet bolting evaluation completed under ATI 2565879-02 B-P B15.10 2RC8037B Body-to-bonnet bolting evaluation completed under ATI 2568716-02 B-P B15.10 2RC8037C Body-to-bonnet bolting evaluation completed under ATI 861305-02 B-P B15.10 2RC8037D Body-to-bonnet bolting evaluation completed under ATI 948560-02 F-A F1.10 2RC17060X Excessive angularity of strut was accepted per EC 403557 C-H C7.10 2SD01CD Low wall thickness discovered during FAG examination was accepted per Design Analysis 053505 (EC 403560) Page 2 of 3 ATTACHMENT 1 TABLE 2 ABSTRACT OF REPAIR/REPLACEMENT ACTIVITIES REQUIRED FOR CONTINUED SERVICE Code Item Description Date Repair/Replacement Class Description Of Work Completed Plan Number 3 Line 2DOF3AB leak at Removed fitting, 12/19/2014 WO# 1781046-01 threaded fitting (IR sealed threads and 2403957) reassembled 3 2SX2183D stuck open Weld in new valve 6/16/2015 WO# 1689691-01 (IR 1583178) (Plan 2-15-029) 3 Through-wall leak at Replaced flanged 8/27/2015 WO# 1712104-01 Line 2SX93AA spool assembly (2-14-001) (IR 2546103) under contingency plan 2 2CV03F bolt sheared Replace bolting with 10/8/2015 WO# 1867200-01 when torqued (incorrect correct material (Plan 2-15-058) material installed, IR 2566608) 2 Reorient clamp for Reorient snubber 10/11/2015 WO# 1762501-20 Snubber2FW08018 clamp 1 2RC8042B valve Replace valve (and 10/13/2015 WO# 1735138-01 diaphragm leaking (IR piping/fittings) per EC (Plan 2-15-047) 1655323) 401903 2 2SI007B flanged Replace valve 10/14/2015 WO# 1763060-12 connection leak (IR 2574472) 1 PT indications in Removed PT 10/16/2015 WO# 1792637-01 2RC01 BB (2B steam indications from (Plan 2-15-005) generator) temporary temporary thermocouple attachment and attachments (IR verified removal 2571599) 2 2Sl20B Weld #2 failed Repair weld that 10/16/2016 WO# 1692238-10 in-process weld RT (IR failed Preservice (2-14-028) 2552333) radioqraphv 1 21C01 M (Seal Table) Tighten mechanical 10/18/2015 WO# 1757626-01 fitting leaks (lncore connections Thimbles F1, N2, C5, discovered with D10, R6, E9, F8, K6, inactive dry boron J10, K12, E11, F14, leakage A11, H15, J14, and L11) 1 Reorient strut Reoriented strut 10/19/2015 WO# 1868960-01 2SI01029X within tolerances (IR 2569199) 1 Reorient strut Reoriented strut 10/19/2015 WO# 1868957-01 2SI01032X within tolerances (IR 2569197) Page 3 of 3 ATTACHMENT 2 A2R18 CONTAINMENT ISi (IWE/IWL)

RESULTS ATTACHMENT2 A2R18 CONTAINMENT ISi (IWE/IWL)

RESULTS REPORT OF CONTAINMENT DEGRADATION Containment inspections were performed in accordance with Subsection IWE (Requirements for Class MC and Metallic Liners of Class CC Components of Light-Water Cooled Power Plants) and IWL (Requirements for Class CC Components of Light-Water Cooled Power Plants) of ASME Section XI, Division 1, (2001 Edition through the 2003 Addenda) along with specified modifications and limitations in 1 OCFR 50.55a. The scope of the examinations during A2R18 included General Visual of all accessible interior and exterior surfaces of Class MC Components, parts, and appurtenances, and metallic shell and penetration liners of Class CC Components. (ASME IWE) REPORT OF CONTAINMENT DEGRADATION General Visual examinations of Accessible Surface Areas (Category E-A, Item 1.11) and Moisture Barriers (Category E-A, Item 1.30) of Containment Vessel Pressure Retaining Boundary were performed to meet the periodic inspection requirements of ASME Section XI, Table IWE-2500-1. In addition to GV examinations, VT-3 exams were also conducted on pressure retaining containment bolted connections that were disassembled during A2R18. No augmented exams of containment liner (Category E-C, Item 4.11 and 4.12) were scheduled for A2R18 (Second Period of the Second Interval Containment ISi}. Exelon Procedures ER-AA-330-007, "Visual Examination of ASME Section XI Class MC Surfaces and Class CC Liners" and ER-AA-335-018 "Visual Examination of ASME /WE Class MC and Metallic Liners of CC Components" were used to perform the examinations.

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

[1 OCFR 50.55a(b)(2)(ix)(A)(2)(i)]:

During the performance of A2R18 General Visual exams under Work Order 1764796, a section of Unit 2 moisture barrier located 4 feet to the left of R-34 was found soft and deformed.

A gap (approx. 4 inches long and 0.5 inches wide) was identified between containment liner and moisture barrier material, however there were no signs of water intrusion past the moisture barrier. IR 2566707 was written to generate a WO 1867510 for the removal, examination and restoration of moisture barrier section at the specified location.

A VT-1 exam was performed on the containment liner after the removal of moisture barrier section which revealed no additional degradation.

The liner surface examined during VT-1 exam was found coated and dry. A baseline GV exam was performed after restoration of moisture barrier with no issues identified.

Extent of Condition:

Evidence of previous pitting was documented in the results of VT-1 exam performed under Work Order 1867510. The area examined during A2R18 had pits that were identified in A2R14, A2R15, or A2R16 and were not repaired in A2R17. Metal loss of varying depths was observed.

It should be noted that this metal thickness loss took place prior to application of Keeler and Long 9600 Series coating in A2R14. The pattern of degradation reported during A2R18 is typical of the entire liner plate surface behind the moisture barrier and contained within a horizontal strip of liner plate, approximately 4" high, around the perimeter of the liner. There was no evidence of corrosion at lower elevations of the liner plate below the MB. Page 1 of 3 ATTACHMENT 2 A2R18 CONTAINMENT ISi (IWE/IWL)

RESULTS Description of the Conditions That Led to the Degradation:

Based on the recorded observations it is evident that the significant portions of the liner plate degradation below the moisture barrier (MB) are attributed to corrosion due to moisture barrier degradation combined with water infiltration between the MB and the liner. In addition, the liner coating system may not have been adequate for the application for which it was used. The liner plate surface below the MB was coated with Carbo Zinc CZ11 in year 2000. Carbo Zinc CZ11 does not tolerate improper surface preparation and is not recommended for use unless white metal condition with a contoured surface profile is achieved.

Since this strip of liner plate below the MB is not easily accessible, it is unlikely that the proper surface preparation was attained during the initial application.

Furthermore, the liner plate surface may not have been completely dried (some moisture left in the wall from the wet Cerafibre resting against it) when the MB was replaced in 2000. In the year 2000, the Cerefibre was found wet and adhering to the metal liner. The liner most likely experienced a slow chronic corrosion rate prior to 2000. The bulk of the liner corrosion likely occurred soon after the year 2000 when the liner below the moisture barrier was coated with Carbo Zinc CZ11. The new coating applied during moisture barrier replacement in A2R08, and used in subsequent outages through A2R17, was Keeler and Long 9600 Series. This coating is used for Service Level I coating in containment.

Unlike the original Carbo Zinc CZ11 coating, Keeler and Long 9600 does not require white metal surface conditions prior to coating and therefore is an effective coating for use on the liner plate behind the moisture barrier. Evaluation of each area, and the result of the evaluation

[1 OCFR 50.55a(b )(2)(ix)(A)(2)(ii)]:

No further evaluation was required for the inaccessible areas of liner because the degraded condition of the moisture barrier was corrected by a replacement activity during A2R18 as per IWE-3122.2.

The liner surface examined during VT-1 was found sealed and the coating was still completely attached.

Description of Necessary Corrective Actions Completed

[1 OCFR 50.55a(b )(2)(ix)(A)(2)(iii)]:

1) IR 2566707 was written to report the gap identified in Unit 2 moisture barrier section located 4 feet to the left of R-34 in A2R18. 2) Work Order 1867510 was generated from the IR to remove and restore a section of moisture barrier. 3) Approximately 37 inches of liner plate directly behind the MB was examined after the removal of moisture barrier section. 4) The VT-1 exam on the containment liner showed no additional degradation.

The liner surface was found coated and dry. 5) A new MB was installed at the area where the existing MB was removed during A2R18. A post installation GV exam of the replaced MB was performed with no cracks or voids which would allow water intrusion.

Page 2 of 3 ATTACHMENT 2 A2R18 CONTAINMENT ISi (IWE/IWL)

RESULTS 6) An Engineering evaluation (EC 398857) from A2R17 provides justification for the acceptability of the liner plate at its thinnest location (4/64") and operation of Unit 2 until A2R19, without additional repair or replacement activities on the containment liner plate. 7) Portions of Class CC liner below the MB have been categorized as Category E-C (Containment Surfaces Requiring Augmented Examination) in the Unit 2 ISi schedule.

Proposed Corrective Actions for A2R19: Perform VT and UT examinations at all augmented areas discovered in A2R16 and A2R17 that were not repaired in A2R17. Conclusions/Findings:

The liner plate is acceptable and capable of performing its intended design function until A2R19 when additional augmented examinations are scheduled. (ATl1433360} (ASME IWL) REPORT OF CONTAINMENT DEGRADATION No evidence of active degradation was identified for ASME Class CC Components during A2R18. Page 3 of 3 Exelon January 21, 2016 BW160006 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Braidwood Station, Unit 2 Facility Operating License No. NPF-77 NRC Docket No. STN 50-457 Exelon Generation Company Braidwood Station 35100 South Route 53, Suite 84 Braceville, 60407-9619 www.exeloncoro.com

Subject:

Braidwood Station, Unit 2 lnservice Inspection Summary Report Enclosed please find the post-outage summary report (i.e., 90 day report) for lnservice Inspection (ISi) examinations conducted during Braidwood Station, Unit 2 Refueling Outage 18 (A2R18). This report is submitted in accordance with the requirements of the American Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code,Section XI, "Rules for the lnservice Inspection of Nuclear Power Plant Components," and ASME Code Case N-532-4, "Repair/Replacement Activity Documentation Requirements and lnservice Summary Report Preparation Submission

-Section XI, Division 1." Attachment 1 provides the Owner's Activity Report (OAR) for ISi activities conducted during A2R18 including a list of items with flaws or relevant conditions that required evaluation for continued service, and an abstract of repair/replacement activities required for continued service. In addition, Attachment 2 provides the results of Containment ISi activities performed in accordance with ASME Section XI, Subsection IWE, "Requirements for Class MC and Metallic Liners of Class CC Components of Light-Water Cooled Power Plants," and Subsection IWL, "Requirements of Class CC Components of Light-Water Cooled Power Plants," with specified modifications and limitations in 1 O CFR 50.55a, "Codes and standards." Please direct any questions you may have regarding this submittal to Mr. George Golwitzer, Regulatory Assurance Manager, at (815) 417-4571.

Marri Marchionda-Palmer Site Vice President Braidwood Station Attachments:

1. Owner's Activity Report (OAR) for A2R18 2. A2R18 Containment ISi (IWE/IWL)

Results cc: Regional Administrator

-NRC Region Ill NRC Senior Resident Inspector-Braidwood Station NRR Project Manager-Braidwood Station Illinois Emergency Management Agency -Division of Nuclear Safety ATTACHMENT 1 FORM OAR-1 OWNER'S ACTIVITY REPORT TABLE 1, ITEMS WITH FLAWS OR RELEVANT CONDITIONS THAT REQUIRED EVALUATION FOR CONTINUED SERVICE TABLE 2, ABSTRACT OF REPAIR/REPLACEMENT ACTIVITIES REQUIRED FOR CONTINUED SERVICE ATTACHMENT 1 FORM OAR-1 OWNER'S ACTIVITY REPORT Plant Braidwood Generating Station, 35100 South Route 53, Suite 84, Braceville, Illinois 60407 Unit No. 2 Commercial Service Date ___

___ Refueling Outage Number ---'-A"""'2""""R""1-"-8

__ (if applicable)

Current Inspection Interval Third Inspection Interval (ISI), Second Inspection Interval (Containment ISI) (l't, 2"d, 3ra, 4ffi, other) Current Inspection Period Second Inspection Period (ISI and Containment (l't, 2 '3id) Edition and Addenda of Section XI applicable to the Inspection Plans ASME Section XI 2001 Edition through 2003 Addenda Date I Revision of Inspection Plans August 5, 2014 (Revision 11), 9/25/2014 (Revision 12), January 26, 2015 (Revision

13) and August 21, 2015 (Revision

14) Edition and Addenda of Section XI applicable to repair/replacement activities, if different than the inspection plans Same as above Code Cases used: N-460, N-508-3, N-508-4, N-513-3, N-532-4, N-532-5, N-566-2, N-586-1, N-597-2, N-613-1, N-639, N-652-1, N-661-1, N-700 N-706-1, N-722-1, N-729-1, N-731, N-751 N-753 CERTIFICATE OF CONFORMANCE I certify that (a) the statements made in this report are correct; (b) the examinations and tests, meet the Inspection Plan as required by the ASME Code,Section XI; and (c) the repair/replacement activities and evaluations supporting the completion of A2R18 conform to the requirements of Section XI (refueling outage number) 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 The Harford Steam Boiler Inspection and Insurance Company of Connecticut of Hartford, Connecticut 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 Section XI. By signing this certificate neither the Inspector nor his employer makes any warranty expressed or implied concerning the repair/ replacement activities and evaluation described in this report. Furthermore, neither the Inspector nor his employer shall be liable in any manner for y personal injury or property damage or a loss of any kind arising from or connected with this inspection (3c/I/ A,//, I, C National Board, State, Province, and Endorsements Date Page 1 of 3 ATTACHMENT 1 TABLE 1 ITEMS WITH FLAWS OR RELEVANT CONDITIONS THAT REQUIRED EVALUATION FOR CONTINUED SERVICE Examination Examination Item Category Number Item Description Evaluation Description D-B 02.10 2DG5045A Pitting observed visually at valve body flange surface was evaluated under (IR 2463461 I EC 385798) D-B 02.10 2CV8444 Body-to-bonnet bolting evaluation completed under ATI 2430862-02 C-H C7.10 2CV8146 Body-to-bonnet bolting evaluation completed under ATI 2566190-02 C-H C7.10 2Sl8808C Body-to-bonnet bolting evaluation completed under ATI 2566198-02 C-H C7.10 2CV8123 Inlet flange bolting evaluation BRW201516203 under WO 1723403-01 B-P B15.10 2RC8001B Bonnet leak off line downgraded from Class 1 to Non-Safety Related under EC 403668 B-P B15.10 2RC8037A Body-to-bonnet bolting evaluation completed under ATI 2565879-02 B-P B15.10 2RC8037B Body-to-bonnet bolting evaluation completed under ATI 2568716-02 B-P B15.10 2RC8037C Body-to-bonnet bolting evaluation completed under ATI 861305-02 B-P B15.10 2RC8037D Body-to-bonnet bolting evaluation completed under ATI 948560-02 F-A F1.10 2RC17060X Excessive angularity of strut was accepted per EC 403557 C-H C7.10 2SD01CD Low wall thickness discovered during FAG examination was accepted per Design Analysis 053505 (EC 403560) Page 2 of 3 ATTACHMENT 1 TABLE 2 ABSTRACT OF REPAIR/REPLACEMENT ACTIVITIES REQUIRED FOR CONTINUED SERVICE Code Item Description Date Repair/Replacement Class Description Of Work Completed Plan Number 3 Line 2DOF3AB leak at Removed fitting, 12/19/2014 WO# 1781046-01 threaded fitting (IR sealed threads and 2403957) reassembled 3 2SX2183D stuck open Weld in new valve 6/16/2015 WO# 1689691-01 (IR 1583178) (Plan 2-15-029) 3 Through-wall leak at Replaced flanged 8/27/2015 WO# 1712104-01 Line 2SX93AA spool assembly (2-14-001) (IR 2546103) under contingency plan 2 2CV03F bolt sheared Replace bolting with 10/8/2015 WO# 1867200-01 when torqued (incorrect correct material (Plan 2-15-058) material installed, IR 2566608) 2 Reorient clamp for Reorient snubber 10/11/2015 WO# 1762501-20 Snubber2FW08018 clamp 1 2RC8042B valve Replace valve (and 10/13/2015 WO# 1735138-01 diaphragm leaking (IR piping/fittings) per EC (Plan 2-15-047) 1655323) 401903 2 2SI007B flanged Replace valve 10/14/2015 WO# 1763060-12 connection leak (IR 2574472) 1 PT indications in Removed PT 10/16/2015 WO# 1792637-01 2RC01 BB (2B steam indications from (Plan 2-15-005) generator) temporary temporary thermocouple attachment and attachments (IR verified removal 2571599) 2 2Sl20B Weld #2 failed Repair weld that 10/16/2016 WO# 1692238-10 in-process weld RT (IR failed Preservice (2-14-028) 2552333) radioqraphv 1 21C01 M (Seal Table) Tighten mechanical 10/18/2015 WO# 1757626-01 fitting leaks (lncore connections Thimbles F1, N2, C5, discovered with D10, R6, E9, F8, K6, inactive dry boron J10, K12, E11, F14, leakage A11, H15, J14, and L11) 1 Reorient strut Reoriented strut 10/19/2015 WO# 1868960-01 2SI01029X within tolerances (IR 2569199) 1 Reorient strut Reoriented strut 10/19/2015 WO# 1868957-01 2SI01032X within tolerances (IR 2569197) Page 3 of 3 ATTACHMENT 2 A2R18 CONTAINMENT ISi (IWE/IWL)

RESULTS ATTACHMENT2 A2R18 CONTAINMENT ISi (IWE/IWL)

RESULTS REPORT OF CONTAINMENT DEGRADATION Containment inspections were performed in accordance with Subsection IWE (Requirements for Class MC and Metallic Liners of Class CC Components of Light-Water Cooled Power Plants) and IWL (Requirements for Class CC Components of Light-Water Cooled Power Plants) of ASME Section XI, Division 1, (2001 Edition through the 2003 Addenda) along with specified modifications and limitations in 1 OCFR 50.55a. The scope of the examinations during A2R18 included General Visual of all accessible interior and exterior surfaces of Class MC Components, parts, and appurtenances, and metallic shell and penetration liners of Class CC Components. (ASME IWE) REPORT OF CONTAINMENT DEGRADATION General Visual examinations of Accessible Surface Areas (Category E-A, Item 1.11) and Moisture Barriers (Category E-A, Item 1.30) of Containment Vessel Pressure Retaining Boundary were performed to meet the periodic inspection requirements of ASME Section XI, Table IWE-2500-1. In addition to GV examinations, VT-3 exams were also conducted on pressure retaining containment bolted connections that were disassembled during A2R18. No augmented exams of containment liner (Category E-C, Item 4.11 and 4.12) were scheduled for A2R18 (Second Period of the Second Interval Containment ISi}. Exelon Procedures ER-AA-330-007, "Visual Examination of ASME Section XI Class MC Surfaces and Class CC Liners" and ER-AA-335-018 "Visual Examination of ASME /WE Class MC and Metallic Liners of CC Components" were used to perform the examinations.

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

[1 OCFR 50.55a(b)(2)(ix)(A)(2)(i)]:

During the performance of A2R18 General Visual exams under Work Order 1764796, a section of Unit 2 moisture barrier located 4 feet to the left of R-34 was found soft and deformed.

A gap (approx. 4 inches long and 0.5 inches wide) was identified between containment liner and moisture barrier material, however there were no signs of water intrusion past the moisture barrier. IR 2566707 was written to generate a WO 1867510 for the removal, examination and restoration of moisture barrier section at the specified location.

A VT-1 exam was performed on the containment liner after the removal of moisture barrier section which revealed no additional degradation.

The liner surface examined during VT-1 exam was found coated and dry. A baseline GV exam was performed after restoration of moisture barrier with no issues identified.

Extent of Condition:

Evidence of previous pitting was documented in the results of VT-1 exam performed under Work Order 1867510. The area examined during A2R18 had pits that were identified in A2R14, A2R15, or A2R16 and were not repaired in A2R17. Metal loss of varying depths was observed.

It should be noted that this metal thickness loss took place prior to application of Keeler and Long 9600 Series coating in A2R14. The pattern of degradation reported during A2R18 is typical of the entire liner plate surface behind the moisture barrier and contained within a horizontal strip of liner plate, approximately 4" high, around the perimeter of the liner. There was no evidence of corrosion at lower elevations of the liner plate below the MB. Page 1 of 3 ATTACHMENT 2 A2R18 CONTAINMENT ISi (IWE/IWL)

RESULTS Description of the Conditions That Led to the Degradation:

Based on the recorded observations it is evident that the significant portions of the liner plate degradation below the moisture barrier (MB) are attributed to corrosion due to moisture barrier degradation combined with water infiltration between the MB and the liner. In addition, the liner coating system may not have been adequate for the application for which it was used. The liner plate surface below the MB was coated with Carbo Zinc CZ11 in year 2000. Carbo Zinc CZ11 does not tolerate improper surface preparation and is not recommended for use unless white metal condition with a contoured surface profile is achieved.

Since this strip of liner plate below the MB is not easily accessible, it is unlikely that the proper surface preparation was attained during the initial application.

Furthermore, the liner plate surface may not have been completely dried (some moisture left in the wall from the wet Cerafibre resting against it) when the MB was replaced in 2000. In the year 2000, the Cerefibre was found wet and adhering to the metal liner. The liner most likely experienced a slow chronic corrosion rate prior to 2000. The bulk of the liner corrosion likely occurred soon after the year 2000 when the liner below the moisture barrier was coated with Carbo Zinc CZ11. The new coating applied during moisture barrier replacement in A2R08, and used in subsequent outages through A2R17, was Keeler and Long 9600 Series. This coating is used for Service Level I coating in containment.

Unlike the original Carbo Zinc CZ11 coating, Keeler and Long 9600 does not require white metal surface conditions prior to coating and therefore is an effective coating for use on the liner plate behind the moisture barrier. Evaluation of each area, and the result of the evaluation

[1 OCFR 50.55a(b )(2)(ix)(A)(2)(ii)]:

No further evaluation was required for the inaccessible areas of liner because the degraded condition of the moisture barrier was corrected by a replacement activity during A2R18 as per IWE-3122.2.

The liner surface examined during VT-1 was found sealed and the coating was still completely attached.

Description of Necessary Corrective Actions Completed

[1 OCFR 50.55a(b )(2)(ix)(A)(2)(iii)]:

1) IR 2566707 was written to report the gap identified in Unit 2 moisture barrier section located 4 feet to the left of R-34 in A2R18. 2) Work Order 1867510 was generated from the IR to remove and restore a section of moisture barrier. 3) Approximately 37 inches of liner plate directly behind the MB was examined after the removal of moisture barrier section. 4) The VT-1 exam on the containment liner showed no additional degradation.

The liner surface was found coated and dry. 5) A new MB was installed at the area where the existing MB was removed during A2R18. A post installation GV exam of the replaced MB was performed with no cracks or voids which would allow water intrusion.

Page 2 of 3 ATTACHMENT 2 A2R18 CONTAINMENT ISi (IWE/IWL)

RESULTS 6) An Engineering evaluation (EC 398857) from A2R17 provides justification for the acceptability of the liner plate at its thinnest location (4/64") and operation of Unit 2 until A2R19, without additional repair or replacement activities on the containment liner plate. 7) Portions of Class CC liner below the MB have been categorized as Category E-C (Containment Surfaces Requiring Augmented Examination) in the Unit 2 ISi schedule.

Proposed Corrective Actions for A2R19: Perform VT and UT examinations at all augmented areas discovered in A2R16 and A2R17 that were not repaired in A2R17. Conclusions/Findings:

The liner plate is acceptable and capable of performing its intended design function until A2R19 when additional augmented examinations are scheduled. (ATl1433360} (ASME IWL) REPORT OF CONTAINMENT DEGRADATION No evidence of active degradation was identified for ASME Class CC Components during A2R18. Page 3 of 3