ML14322A149

R.E. Ginna - Steam Generator Tube Inspection Report, End of Cycle 37 Refueling Outage, May 2014

ML14322A149
Person / Time
Site:	Ginna
Issue date:	11/13/2014
From:	Mogren T Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
WPLNRC-1002917
Download: ML14322A149 (15)

Text

dR.E. Ginna Nuclear Power PlantE1503 Lake Rd.Exelon Generation. Ontario, NY 14519www.exeloncorp.comNovember 13, 2014U.S. Nuclear Regulatory CommissionATTN: Document Control DeskWashington, DC 20555-0001R.E. Ginna Nuclear Power PlantFacility Operating License No. DPR- 18NRC Docket No. 50-244

Subject:

2014 Steam Generator Tube Inspection ReportExelon Generation Company, LLC (Exelon) completed an examination of the tubing in the R.E.Ginna Nuclear Power Plant (Ginna) steam generators during the end of Cycle 37 Refueling Outage.Ginna Technical Specification 5.6.7 requires a report of the inspection results be submitted within180 days after reactor coolant temperature exceeds 200'F. Attachment I contains the document,"Steam Generator Tube Inspection Report, End of Cycle 37 Refueling Outage, May 2014," whichdocuments the results of the examinations.There are no regulatory commitments contained in this letter.Should you have any questions regarding this submittal, please contact Thomas Harding at 585-771-5219.Respectfully,Thomas MogrenDirector, Site EngineeringR.E. Ginna Nuclear Power Plant, LLCTM/kc

Attachment:

Steam Generator Tube Inspection Report, End of Cycle 37 Refueling Outage, May2014cc: NRC Regional Administrator, Region INRC Project Manager, GinnaNRC Resident Inspector, GinnaIDT7V$DLi0 kAk C- -- 100oc?1 -7 AttachmentSteam Generator Tube Inspection Report,End of Cycle 37 Refueling Outage, May 2014 R. E. Ginna Nuclear Power Plant, LLCSTEAM GENERATOR TUBE INSPECTION REPORTEND OF CYCLE 37 REFUELING OUTAGEMAY 20141503 Lake RoadOntario, N.Y. 14519 Steam Generator Tube Inspection Report Page 2 of 13EOC 37 Refueling OutageTABLE OF CONTENTS1.0 IN T R O D U C T IO N ............................................................................................ ..32 .0 S U M M A R Y ..................................................................................................... ..33 .0 R E P O R T ................................................................................................... .....53.1 Scope of Inspections Performed on each Steam Generator (TS 5.6.7.a.) ....... 53.1.1 Prim ary Side Base Scope ........................................................................ 63.1.2 Primary Side Special Interest Scope (Scope Expansion) ........................ 73.1.3 Secondary Side Inspection Scope .......................................................... 73.2 Active Degradation Mechanisms Found (TS 5.6.7.b.) .................................... 83.3 Nondestructive Examination Techniques Utilized for each DegradationM echanism (T S 5.6.7.c.) ............................................................................. ..93.4 Location, Orientation (if Linear), and Measured Sizes (if Available) of Service-Induced Indications (TS 5.6.7.d.) ................................................................... 93.5 Number of Tubes Plugged During the Inspection Outage for each ActiveDegradation Mechanism (TS 5.6.7.e.) ........................................................ 113.6 Total Number and Percentage of Tube Plugs to-Date (TS 5.6.7.f.) .............. 113.7 The Results of Condition Monitoring, including the Results of Tube Pulls and In-S itu T esting (TS 5.6.7.g .) .......................................................................... ..114 .0 A C R O N Y M S ................................................................................................. ..125 .0 R E F E R E N C E S .............................................................................................. ..13 Steam Generator Tube Inspection Report Page 3 of 13EOC 37 Refueling Outage

1.0 INTRODUCTION

The R.E. Ginna Nuclear Power Plant (Ginna) design has two (2) re-circulatingdesign steam generators (SG) designed and fabricated by Babcock and Wilcox(BWI) of Cambridge, Ontario, Canada. The nomenclature used for fabricationand subsequent in-service inspections is BWI #34 (SG-A) and BWI #35 (SG-B).Each BWI steam generator was designed to contain 4765 tubes. One tube ineach steam generator was removed from service during fabrication by means ofa shop welded Inconel 690 plug. SG-A contains 4764 open tubes, and SG-B hadfour (4) tubes plugged at End of Cycle (EOC 32) due to a loose part that bringsthe total to 4760 open tubes. The tubing material is thermally treated Inconel 690having a nominal outer diameter (OD) of 0.750 inch and a nominal wall thicknessof 0.043 inch. The nominal thickness of the tube sheet is 25.25 inches, with a fulldepth hydraulic expansion of all the tubes into the tube sheet material.The tubes are supported in the straight section by eight 410 stainless steel latticegrid supports which are comprised of high, medium, and low bars. The tubes aresupported in the U-bend by ten 410 stainless steel fan bar / collector barassemblies.Ginna Technical Specifications (TS) 5.5.8.d provides the requirements for SGinspection frequencies. The TS requires that 100% of the tubes are to beinspected at sequential periods of 144, 108, 72, and, thereafter, 60 effective fullpower months (EFPM). Additionally, inspect 50% of the tubes by the refuelingoutage nearest the midpoint of the period and the remaining 50% by the refuelingoutage nearest the end of the period. At the beginning of the Ginna EOC 37refueling outage, Ginna was at 15.54 EFPY (186.48 EFPM). Therefore, Ginnawas at 42.48 EFPM within the second 108 EFPM inspection period.In accordance with the Ginna TS 3.4.17, "Steam Generator (SG) Tube Integrity,"Ginna TS 5.5.8, "Steam Generator (SG) Program," and American Society ofMechanical Engineers (ASME) Boiler and Pressure Vessel (B&PV) Code SectionXI, 2004 Edition, IWB 2500-1, Examination category B-Q, item B16.20, SG eddycurrent examinations were performed during the Ginna EOC 35 refueling outage.All inspections were completed in accordance with Ginna TS 5.5.8.2.0 SUMMARYThe EOC 37 2014 refueling outage (RFO) was the eighth in-service inspection ofthe Ginna SGs and entered Mode 4 on May 18, 2014. A degradation assessmentwas performed prior to the EOC 37 inspection to assure qualified inspection Steam Generator Tube Inspection Report Page 4 of 13EOC 37 Refueling Outagetechniques would be used to detect any existing and potential damagemechanisms.The modes of tube degradation detected during the EOC 37 RFO weresecondary side foreign object wear, and minor tube to lattice grid wear.Foreign objects were also detected on the tubesheet secondary face of both "A"and "B" steam generators (SG). A process was established to prioritize theremoval of foreign objects, with the highest priority given to the foreign objectsthat posed a higher risk to tube integrity. Each foreign object that was detectedand left in-service was evaluated in accordance with EPRI Steam GeneratorIntegrity Assessment Guidelines, Revision 3, with Ginna SG plant-specificthermal performance inputs. The basis for leaving each foreign object in-serviceis the disposition of each foreign object evaluation.Tube manufacturing anomalies were sampled with no detectable degradationand no detectable changes since the original SG manufacturing baseline.In-service denting at the cold leg tubesheet secondary face was initially detectedduring the 2008 RFO and was again detected during the EOC 37 2014examination. While denting is not considered degradation as defined in the EPRISteam Generator Examination Guidelines, it is considered worthy of discussion.During the 2008 RFO eighty (80) tubes were identified with dents in the cold legof SG-B and two (2) dented tubes in the cold leg of SG-A. The detected dentpopulations were based upon an approximately 58% bobbin-coil examinationplan. The 2014 RFO detected dent populations were based upon a 100% bobbincoil examination.The 100% full length 2014 RFO eddy-current bobbin-coil examination planincorporated potential extent of condition for denting at the tubesheet secondaryface. This scope was the same for both the "A" and "B" SG.The bobbin examination detected no additional cold leg top of tubesheet dents inSG-A. Since 2011 there were four (4) dents detected in SG-A.The bobbin examination identified ten new cold leg top of tubesheet dents in SG-B. Based upon the 2014 scope there were two hundred and forty seven (247)cold leg top of tubesheet dents and one (1) hot leg top of tubesheet dent in SG-B. The 10 newly reported dents had voltages that were near the limit ofdetectability. The denting proved to be arrested when comparing the historicalindication voltages.

Steam Generator Tube Inspection Report Page 5 of 13EOC 37 Refueling OutageAll dents identified by the bobbin coil at the hot leg and cold leg top of tubesheetwere inspected using a "D" probe. The "D" probe is a three coil probe containinga +Point coil, 0.115" pancake coil, and a non-surface riding 0.080" pancake coil.The data collected with the "D" probe was analyzed for defects using the +Pointand 0.115 pancake coil, no degradation was detected. A comparison of the2011 RFO to 2014 RFO inspection results indicates that no active continuedprogression of denting is occurring.3.0 REPORT3.1 Scope of Inspections Performed on each Steam Generator (TS5.6.7.a.)

Steam Generator Tube Inspection ReportEOC 37 Refueling OutagePage 6 of 133.1.1 Primary Side Base ScopeScope SG- A SG-BBobbin Probe: 4188* 4154100% Full Length of open tubes 575 low rows 606 low rowstested H/L and tested H/L andC/L and 1 tube C/Ldownsized for Total tests: 4760restrictionTotal tests: 4764Rotating Probe: 616 619Periphery and no tube laneHot Leg expansion transition (TSH +3")Rotating Probe: 194 168Bounding of previous foreign objectsevaluated but not removed, andmanufacturing anomalies.Hot Leg expansion transitioncombination of extents (TSH +/- 3"),(TSH +5"-3")Rotating Probe: 7 38Bounding of previous foreign objectsevaluated but not removed, andmanufacturing anomalies.Cold Leg expansion transitioncombination of extents (TSC +/- 3"),(TSC +5"-3")Rotating Probe: 647 632Periphery and no tube laneCold Leg expansion transition (TSC +3")Rotating Probe: 4 237Top of tubesheet dents detected in2011Cold Leg expansion transition (TSC+5"1-3")Divider plate / divider-plate weld 1 1visual inspection100% Plug visual inspection 1 tube (2 plugs) 5 tubes (10 plugs)

Steam Generator Tube Inspection ReportEOC 37 Refueling OutagePage 7 of 13*One tube in SG-A (not included in 3241) was restricted with a 0.610" diameterbobbin probe in the U-bend. This tube was tested along its full length with acombination bobbin coil and rotating coil examinations.3.1.2 Primary Side Special Interest Scope (Scope Expansion)Scope SG-A SG-BRotating Probe: 38 281Special interest -MBMs, DNTs, Bobbinspecial interest, tube-to-tube proximityGhent probe: 0 1Special interest top of tubesheetExpansion for Bounding of new foreign 12 75objects and PLPs identified by FOSAR orEddy-Current Hot-Leg expansiontransition extents (TSH +5"-3")Expansion for Bounding of new foreign 0 25objects and PLPs identified by FOSAR orEddy-Current Cold-Leg expansiontransition extents (TSC +5"-3")Newly identified top-of-tubesheet denting 0 10Cold-Leg expansion transition (TSC +5"-3")Newly identified top of tubesheet denting 0 0Hot-Leg expansion transition (TSC +5"-3")3.1.3 Secondary Side Inspection ScopeSG-A:0 FOSAR Inspection (top of tubesheet) prior to Sludge Lance* TTS In-Bundle inspection prior to Sludge Lance" FOSAR Inspection (top of tubesheet) Post-Sludge Lanceo 100% of Annuluso 100% of No tube laneo Blowdown & drain holeso Shroud supports Steam Generator Tube Inspection Report Page 8 of 13EOC 37 Refueling Outageo Inspection of tube support structuresTTS In-Bundle Inspection Post-Sludge Lanceo Previously identified foreign objectso Eddy-current-detected potential loose parts (PLP)SG-B:* FOSAR Internals Inspection (top of tubesheet) prior to Sludge Lance* TTS In-Bundle Inspection prior to Sludge Lance* FOSAR Inspection (top of tubesheet) Post-Sludge Lanceo 100% of Annuluso 100% of No tube laneo Blowdown & drain holeso Shroud Supportso Inspection of tube support structures* TTS In-Bundle Inspection post-Sludge Lanceo Previously identified foreign objectso Eddy-current-detected potential loose parts (PLP)* Upper Internals Inspectiono Primary and Secondary Moisture Separators, structural welds, etc.* Upper Bundle Inspectiono Tube bundle, tube support structures, structural components, etc.3.2 Active Degradation Mechanisms Found (TS 5.6.7.b.)The only detected tube degradation was volumetric resulting from foreign objectwear and tube to lattice grid support wear. There were a total of 7 wear locationsin 6 tubes (3 new tube locations detected in 2014). These were sized with thetechniques in Table 1.In addition, during the comprehensive secondary side upper internalsexaminations in SG-B, very minor flow accelerated corrosion to moderate flowaccelerated corrosion was visually detected in approximately 65 of 85 secondarysteam separator base plates. The results of these exams were acceptable for the Steam Generator Tube Inspection ReportEOC 37 Refueling OutagePage 9 of 13next operating interval, examinations that include improved quantitative resultsare planned.3.3 Nondestructive Examination Techniques Utilized for eachDegradation Mechanism (TS 5.6.7.c.)See Table 1.3.4 Location, Orientation (if Linear), and Measured Sizes (ifAvailable) of Service-Induced Indications (TS 5.6.7.d.)See Table 1.

Steam Generator Tube Inspection ReportEOC 37 Refueling OutagePage 10 of 13Table 1SG Row Col. Location Degradation ETSS NDEType MeasurementParameter(s)A 1 25 05H -1.54" Volumetric 96910.1 10% though wall(New Lattice + Point (TW), .35" lengthwear) x .39" (60) widthusing flaw peaksA 91 51 05H +0.34" Volumetric 21998.1 32% TW, .35"(Existing + Point length x .39"foreign (600) width usingmaterial flaw peakswear)A 53 85 02H +36.93" Volumetric 27901.2 21% TW, .19"(0.5" below (Existing + Point length x .39"03H) foreign (600) width usingmaterial flaw peakswear)B 2 20 06C -1.62" Volumetric 96910.1 6% TW, .26"(New Lattice + Point length x .45'wear) (690) width usingflaw peaksB 78 24 01H +1.20" Volumetric 21998.1 21% TW, 1.41"(Existing + Point length x .68"foreign (1040) widthmaterial using flaw peakswear)B 78 24 01H +0.91" Volumetric 21998.1 25% TW, .31"(Existing + Point length x .40"foreign (61') width usingmaterial flaw peakswear)B 2 78 02H -1.82" Volumetric 21998.1 19% TW, .36"(New foreign + Point length x .45"material (690) width usingwear) flaw peaks Steam Generator Tube Inspection Report Page 11 of 13EOC 37 Refueling Outage3.5 Number of Tubes Plugged During the Inspection Outage foreach Active Degradation Mechanism (TS 5.6.7.e.)There were no tubes that required removal from service by plugging during theGinna 2014 RFO examination.3.6 Total Number and Percentage of Tube Plugs to-Date (TS 5.6.7.f.)Table 2SG-A SG-BTubes plugged to date 1 5Tubes Installed 4765 4765% of tubes plugged to date 0.02% 0.10%The tube plugging performed to-date included 1 tube in each SG during pre-service examinations. The additional 4 tubes plugged in the SG-B were from aforeign object that was not able to be removed during the 2005 RFO in-serviceexamination.3.7 The Results of Condition Monitoring, including the Results ofTube Pulls and In-Situ Testing (TS 5.6.7.g.)A condition monitoring assessment was performed for each in-servicedegradation mechanism detected during the EOC 37 2014 RFO SG examination.The condition monitoring assessment was performed in accordance with GinnaTS 5.5.8.a, NEI-97-06, EPRI Steam Generator Integrity Assessment Guidelines,Revision 3, and the EPRI Steam Generator Degradation Specific ManagementFlaw Handbook, Revision 1. For each identified degradation mechanism, the as-found condition was compared to the appropriate performance criteria for tubeintegrity, accident induced leakage and operational leakage as defined in TS5.5.8.b. For each damage mechanism a tube structural limit was determined toensure that SG tube integrity would be maintained over the full range ofoperating conditions and design basis accidents. This included retaining a safetyfactor of 3.0 against burst under normal steady-state full power operationprimary-to-secondary pressure differential and a safety factor of 1.4 against burstunder the limiting design basis accident pressure differential.

Steam Generator Tube Inspection Report Page 12 of 13EOC 37 Refueling OutageThe as-found condition of each degradation mechanism found during the EOC37 RFO was shown to meet the appropriate limiting structural integrityperformance parameter with a probability of 0.95 at 50% confidence level,including consideration of relevant uncertainties.The following section provides a summary of the condition monitoringassessment for each damage mechanism.The largest foreign object wear indication found during EOC 37 2014 RFOexamination was 32% TW as measured by the EPRI Appendix H qualifiedtechnique 21998.1. The EPRI Steam Generator Degradation SpecificManagement Flaw Handbook, Revision 1, provides the methodology for thedetermination of structural limits and condition monitoring limits for various typesof tube degradation. Following the flaw handbook methodology that discussesthe structural limit for volumetric flaws of a given axial extent and limitedcircumferential extent (less than 135 degrees), the condition monitoring limit of46% TW--which includes the total system uncertainty--is well above the 32% TWNDE sizing.There were no tube pulls or in-situ pressure testing performed during the EOC 372014 RFO.4.0 ACRONYMSASME American Society of Mechanical EngineersC/L Cold LegTS Technical SpecificationEFPM Effective Full Power MonthsEFPY Effective Full Power YearsEOC End of CycleEPRI Electrical Power and Research InstituteETSS Examination Technique Specification SheetFOSAR Foreign Object Search and RetrievalH/L Hot LegNEI Nuclear Energy InstitutePLP Potential Loose PartSG Steam GeneratorTSC Tubesheet ColdTSH Tubesheet HotTTS Top of TubesheetTW Through-Wall Steam Generator Tube Inspection Report Page 13 of 13EOC 37 Refueling Outage

5.0 REFERENCES

5.1 Ginna Technical Specifications5.2 ASME section XI, 2004 Edition5.3 Fleet Steam Generator Program, CNG-AM-7.015.4 Steam Generator Program Guidelines, Nuclear Energy Institute,NEI 97-06, Revision 25.5 EPRI PWR Steam Generator Examination Guidelines, Revision 75.6 EPRI Steam Generator Integrity Assessment Guidelines, Revision 35.7 EPRI Steam Generator Degradation Specific Management Flaw Handbook,Revision 1