ML13037A506

Inservice Inspection Summary Report

ML13037A506
Person / Time
Site:	Braidwood
Issue date:	02/06/2013
From:	Enright D Exelon Generation Co
To:	Office of Nuclear Reactor Regulation, Document Control Desk
References
BW130007
Download: ML13037A506 (10)

Text

February 6, 2013 BW130007 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

Subject:

Braidwood Station, Unit 2 Inservice Inspection Summary Report Enclosed please find the post-outage summary report (i.e., 90 day report) for inservice inspection (lSI) examinations conducted during Braidwood Station, Unit 2 Refueling Outage 16 (A2R16).

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 Inservice Inspection of Nuclear Power Plant Components," and ASME Code Case N-532-4, "Repair/Replacement Activity Documentation Requirements and Inservice Summary Report Preparation Submission - Section XI, Division 1."

Attachment 1 provides the Owner's Activity Report (OAR) for lSI activities conducted during A2R16 including a list of items with flaws or relevant conditions that required evaluation for continued service and an abstract of repair/replacements activities required for continued service.

In addition, Attachment 2 provides the results of Containment lSI 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 10 CFR 50.55a, "Codes and standards."

Please direct any questions you may have regarding this submittal to Mr. Chris VanDenburgh, Regulatory Assurance Manager, at (815) 417-2800.

Respectfully, aniel J. Enright Site Vice President Braidwood Station Attachments:

1. Owner's Activity Report (OAR) for A2R16

2. A2R16 Containment lSI (IWE/IWL) Results cc: Regional Administrator - NRC Region III NRC Senior Resident Inspector - Braidwood Station NRR Project Manager - Braidwood Station Illinois Emergency Management Agency - of Nuclear

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-l OWNER'S ACTIVITY REPORT Report Number A2R16

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Plant Braidwood Generating Station, 35100 South Route 53, Suite 84, Braceville, Illinois 60407 Unit No. 2 CommerCial Service Date October 16, 1988 Refueling Outage Number -=-:=.:..::;:::.::...._--- A2R16

-=--:::Of:-a-pp-::lic-a7":bl:-:e) - -

Current Inspection Interval Third Inspection Interval (lSI), Second Inspection Interval (Containment lSI)

(1 st, 2nd , 3rd, 4111, other)

Current Inspection Period Second Inspection Period (lSI and Containment lSI)

(is'. 2nd, 3rd)

Edition and Addenda of Section XI applicable to the Inspection Plans ASME Section XI 2001 Edition through 2003 Addenda Date / Revision of Inspection Plans October 12, 2012/ Revision 7 and November 1, 2012 / Revision 8 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-513-3, N-532-4, N-566-2, N-586-1, N-597-2, N-613-1, N-624, N-639, N-648-1, N-652-1, N-661-1, N-685, N-695, N-696, N-700, N-706-1, N-722-1, N-729-1, N-731, N-739, N-751, N-753, N-770-1 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 A2R16

~~~------

conform to the requirements of Section XI (refueling outage number)

Signed !:::!.~t..!:::.~~::-;-t-:.~~~l--:--~B~r~en~d~a~n.:J:..:.C~a:!:s:=ey!!,~I.::SI~P!::!r~o~gr~a~m~O~w~n~e~r__ Date CERTIFICATE OF INSERVICE INSPECTION I, the undersigned, holding a valid commission issued by the National Board of Boiler and Pressure Vessel Inspectors and the State or Province of Illinois and employed by HSBCT of -..;..;H..;;;a;;.;rtf;;..;o;.;.r..;;d...

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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. Furthenmore, neither the Inspector nor his employer shall be liable in any manner for any personal injury or property damage or a loss of any kind arising from or connected with this inspection L~ L~ ~ Commissions ~  ::\;I "'B l S- u. Ah.l \. c- ""I..'--::lt l 0 8 S; (Inspector's Signature) National Board, State, Province, ahd Endorsements Date \- ""2.. <4 - ~ \.~

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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 O-B 02.10 2AB8547 Body-to-bonnet leak evaluation completed under AT11287853-02 per IWA-5250 methodology O-B 02.10 2SX25AA-6" Minimum wall thickness evaluation completed and reconfirmed (IR 1321545) under EC 356580 C-H C7.10 2CV8355C BOdy-to-bonnet leak evaluation completed under ATI1334977-02 per IWA-5250 methodology C-H C7.10 2RH02AB Flange bolting evaluation completed under AT11406129-02 using IWA-5250 methodology C-H C7.10 2RH02BB Flange bolting evaluation completed under AT11406123-02 using IWA-5250 methodology O-B 02.10 2FC48A / 2FC02F Leak at filter housing mechanical connection evaluated under ATI 1424457-02 C-H C7.10 2CV01FB Leak at filter housing mechanical connection evaluated under ATI 1424771-02 C-H C7.10 2SI07MA Flange bolting evaluation completed under ATI 1446932-02 using Code Case N-566-2 methodology C-H C7.10 2PS9350B Body-to-bonnet leak evaluation completed under AT11426386-02 using Code Case N-566-2 methodology Page 2 of 4

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 2DG01KB-X1 Replaced heat exchanger stationary and 12114/2012 WO 1413358-01 floating heads, and flange bolting (Plan 2-12-063) 3 2DG01KB-X2 Replaced heat exchanger stationary 12/14/2012 WO 1413643-01 channel head (Plan 2-12-069) 3 2DG5048B Replaced valve with internal corrosion 12/11/2012 WO 1410077-01 (Plan 2-13-001) 3 2AF050B Tightened leaking plugs on newly installed 11/6/2012 WO 1588284-01 accumulator tank 2 2S18825 Retorqued body-to-bonnet flange bolting 11/4/2012 WO 1587724-01 2 2CV8368C Replaced existing check valve due to 11/2/2012 WO 1421931-01 galling of threaded cover (Plan 2-12-033) 3 2DG01KA-X1 Retorqued bolting on packed end of heat 11/2/2012 WO 1586454-01 exchanger 3 2WOO07B Replaced flange bolting exhibiting minor 10/31/2012 WO 971146-01 corrosion (Plan 2-12-012) 2 2CV8323A Retorqued body-to-bonnet flange bolting 10/31/2012 WO 1586456-01 2 2CV8321A Replaced bonnet stud damaged during 10/30/2012 WO 1582330-01 valve disassembly (and accompanying hex (Plan 2-12-092) nut) 2 2CV8321A Remove indication discovered during in- 10/30/2012 WO 1582330-01 process NDE (IR 1430939) by flapping 1 2SI-17-B1 Replaced existing flange bolting exhibiting 10/29/2012 WO 1441321-01 minor corrosion (Plan 2-12-042) 2 2CV8401B Replaced existing plug (and stem) due to 10/29/2012 WO 1485044-01 valve binding (Plan 2-12-036) 1 2RY8010C Replaced existing inlet flange stud 10/29/2012 WO 1497592-01 damaged during shipment (Plan 2-12-028) 3 2CC31B Replaced eXisting flange CC-25-F-2 bolting 10/28/2012 WO 683812-01 exhibiting minor corrosion (Plan 2-12-093) 2 2SI01C Proactively replaced existing flange bolting 10/28/2012 WO 1473658-01 during Boric Acid Corrosion Control (Plan 2-12-029) program inspection 2 2FW04017S Replaced damaged load stud on snubber 10/27/2012 WO 1583902-01 (Plan 2-12-072) 1 2RC01BA Plugged steam generator tubes based on 10/27/2012 WO 1439525-02 eddy current results (Plan 2-12-038) 1 2RC01BD Plugged steam generator tubes based on 10/27/2012 WO 1444327-02 eddy current results (Plan 2-12-040) 1 2RC01BB Plugged steam generator tubes based on 10/26/2012 WO 1444872-02 eddy current results (Plan 2-12-039) 1 2RC01BC Plugged steam generator tubes based on 10/26/2012 WO 1445874-02 eddy current results (Plan 2-12-032) 2 2RH05003S Replace PSA-1/4 snubber that failed 10/26/2012 WO 1584482-01 functional test (Plan 2-12-090) 1 2CV14001S Replace PSA-1 snubber that failed 10/26/2012 WO 1583232-01 functional test (Plan 2-12-071) 2 2RH8735 Retorqued body-to-bonnet flange bolting 10/26/2012 WO 1584475-01 Page 3 of 4

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 2 2RH0501X Staked dislodqed spherical bearinq on strut 10/26/2012 WO 1584775-01 2 2SI06335X Staked dislodged spherical bearing on strut 10/26/2012 WO 1584835-01 2 2RH607 Replace valve flange bolt exhibiting minor 10/25/2012 WO 1583564-01 corrosion (Plan 2-12-098) 2 2S18840 Retorqued body-to-bonnet flange bolting 10/25/2012 WO 1584395-01 2 2RH607 Replace valve flange bolt exhibiting minor 10/25/2012 WO 1583564-01 corrosion (Plan 2-12-098) 3 2SX71077G Replace nonconforming u-bolt 10/24/2012 WO 978594-01 (Plan 2-10-011) 2 2RC01BC Replace steam generator secondary side 10/23/2012 WO 1451104-01 manway cover MJ-19B (Plan 2-12-095) 1 2SI04023X Corrected skewed pipe clamp observed by 10/22/2012 WO 1584258-01 NRC inspector (IR 1428005) 2 2CS01AA Replaced existing flange bolting exhibiting 9/28/2012 WO 1570887-01 minor corrosion (Plan 2-12-059) 2 2CS019B Retorqued body-to-bonnet bolting 8/21/2012 WO 1475936 2 2CS046B RetorQued body-to-bonnet boltinq 8/1212012 WO 1474969-01 2 2RH01B RetorQued heat exchanger flange bolting 7/30/2012 WO 1560286-01 3 2FC01A Remove heat exchanger flange bolting for 7/10/2012 WO 1520350-01 VT -1 and retorque bolting 3 2DG01KA-X1 Replaced existing stationary channel on 3/9/2012 WO 1394162-01 heatexchanqer. (Plan 2-12-030) 3 2DG01KA-X2 Replaced existing stationary channel on 3/9/2012 WO 1394163-01 heat exchanger. (Plan 2-12-031)

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ATTACHMENT 2 A2R16 CONTAINMENT lSI (IWElIWL) RESULTS

ATTACHMENT 2 A2R16 CONTAINMENT 151 (lWE/lWL) RESULTS REPORT OF CONTAINMENT DEGRADATION Containment inspections are 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, with specified modifications and limitations in 10CFR 50.55a. A limited scope of IWE inspections was completed during A2R16. The completed surveillances for IWE contain all the exam ination details along with indications recorded and their associated evaluations required by ASME Section XI.

ASME IWE REPORT OF CONTAINMENT DEGRADATION Augmented Section XIIWE examinations of the Class CC liner examinations for the third interval were performed in accordance with the requirements of ASME Section XI, Table IWE-2500-1, Category E-C, "Containment Surfaces Requiring Augmented Examination". The scope of the examinations included areas of the liner below the moisture barrier.

Exelon Procedures ER-AA-330-007, "Visual Examination of ASME Section XI Class MC Surfaces and Class CC Uners", ER-AA-335-018 "Visual Examination of ASME IWE Class MC and Metallic Liners of CC Components", and ER-AA-335-004 "Ultrasonic Measurement of Material Thickness and Interfering Conditions" were used to perform the exam inations.

A description of the type and estimated extent of the conditions that led to the degradation [10CFR SO.SSa(b)(2)(ix)(A)(1)]:

The most notable degradation was liner pitting just below the moisture barrier (MB) resulting in metal loss of varying depths. Maximum pit depth identified was 10/64" (found at only one location).

Extent of Condition:

The scope of examinations was extended based on identification of the 10/64" pitting. The overall scope of areas examined was in excess of 50% of the liner surface adjacent to the MB. These extended examinations also indicated that the liner plate contained numerous pits in the areas below the MB with pit depth averages to less than or equal to 3/64" and pits with larger depths occurring less frequently. This pattern is typical of the entire liner plate surfaces below the MB.

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 MB are attributed to corrosion. The liner plate surface below the MB was coated with Carbo Zinc CZ11 in year 2000. Carbo Zinc CA 11 does not tolerate improper surface preparation and is not recommended for use unless white metal conditions with 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 prior to application of the coating.

Furthermore, the liner plate surface may not have been completely dried (some moisture left in the wall from the wet Cerafibre material resting against it) when the MB was replaced in 2000. In the year 2000 the Cerafibre material was found wet and adhering to the metal liner. The liner most likely experienced a slow chronic corrosion rate prior to 2000. After the year 2000 when the MB was removed, the bulk of the liner corrosion probably occurred in the early years after the year 2000 when MB was replaced. The new coating applied in A2R14, A2R15 and A2R16 was Keeler and Long 9600 Series used for Service Level I coating in containment which it does not require white metal surface conditions. It is noted that the remaining areas (approximately 200' or of the Page 1 of 3

ATTACHMENT 2 A2R16 CONTAINMENT lSI (IWElIWL) RESULTS liner plate behind the MB that have not been exposed so far are planned for visual examinations (any other supplemental examinations as necessary) during the A2R17 refueling outage.

Evaluation of each area, and the result of the evaluation

[10CFR SO.S5a(b)(2)(ix)(A)(3):

An engineering evaluation (Engineering Change No. 390993) was performed to address all the indications since the corrosion leading to the degraded condition is the same contributor affecting the same component (liner plate). The evaluation determined that the liner plate with the highest degraded condition (10/64") will remain operational and meets its intended design function until A2R17 when additional visual and supplemental examinations are scheduled.

Description of Necessary Corrective Actions Completed

[10CFR SO.SSa(b)(2)(ix)(A)(3)]:

1) Approximately an additional 43' of liner plate directly below the MB was examined beyond the original scope (approximately 183') using the VT -1 (Detailed Visual) method after the MB was removed.

2) Ultrasonic thickness readings were performed near the areas with metal loss ;::6/64" to document actual liner plate thicknesses in the vicinity of the pitted areas.

3) An evaluation was completed to provide justification for the acceptability of the liner plate at its thinnest location and provided assurances that additional margin exists for operation until A2R17 without repair or replacement activities.

4) The liner surfaces at all the exposed locations where the MB had been removed were prepared for Keeler and Long 9600 series coating used for Level I coating applications in containment that was applied during A2R16 along with a new Cerafibre and newly installed MB.

5) A new MB was installed at all areas where the MB was removed. VT-3 exam was performed after the reinstallations on the entire MB and no cracks were found to allow water intrusion.

6) Portions of Class CC liner below the MB exceeding 1/64" pit depth have been categorized as Category E-C in the lSI schedule.

Proposed Corrective Actions for A2R17:

1) Schedule containment liner plate repairs below the MB at locations to be determined by the Responsible Individual.

2) Schedule VT-1 examinations of the liner plate at all remaining areas that were not visually examined in A2R14, A2R15 or A2R16 and perform Volumetric Exams as appropriate.

Conclusions/Findings:

The liner plate containing the degraded conditions below the MB in Unit 2 containment as identified during A2R16 refueling outage is acceptable and capable of performing its intended design function until A2R17 when additional examinations, NDE, and potential repairs will be performed.

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ATTACHMENT 2 A2R16 CONTAINMENT 151 (IWEIIWL) RESULTS ASME IWL REPORT OF CONTAINMENT DEGRADATION No evidence of degradation was identified for ASME Class CC Components during this period.

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