ML14120A496: Difference between revisions

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{{Adams
#REDIRECT [[1CAN041404, Responses to RAIs 1R24 Steam Generator Tube Inspection Report]]
| number = ML14120A496
| issue date = 04/30/2014
| title = Arkansas Nuclear One, Unit 1, Responses to RAIs 1R24 Steam Generator Tube Inspection Report
| author name = Pyle S L
| author affiliation = Entergy Operations, Inc
| addressee name =
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000313
| license number = DPR-051
| contact person =
| case reference number = 1CAN041404
| document type = Letter
| page count = 22
}}
 
=Text=
{{#Wiki_filter:1CAN041404April 30, 2014U.S. Nuclear Regulatory CommissionAttn: Document Control DeskWashington, DC  20555
 
==SUBJECT:==
Responses to RAIs Regarding 1R24 Steam GeneratorTube Inspection ReportArkansas Nuclear One, Unit 1Docket No. 50-313 License No. DPR-51
 
==REFERENCE:==
: 1. Entergy letter dated October 23, 2013, "Steam Generator TubeInspection Report - 1R24", (1CAN101306)(ML13296A746)2. NRC letter dated April 1, 2014, "Request for Additional InformationRegarding the Steam Generator Tube Inspection Report for Refueling Outage 1R24 (TAC NO. MF3251)(1CNA041401)(ML14078A112)
 
==Dear Sir or Madam:==
Entergy Operations, Inc. submitted the Arkansas Nuclear One, Unit 1 Steam Generator TubeInspection Report for refueling outage 1R24 in accordance with Technical Specifications 5.5.9"Steam Generator (SG) Program" via Reference 1. The NRC is currently reviewing thissubmittal and has determined that additional information is needed to complete its review.Reference 2 provides the request for the needed additional information. Attached are theresponses to the requests.There are no new commitments contained in this submittal.Should you have any questions regarding this report, please contact me.
Sincerely,Original signed by David B. Bice for Stephenie L. PyleSLP/rwcAttachment Responses to RAIs Regarding 1R24 Steam Generator Tube Inspection ReportEntergy Operations, Inc.1448 S.R. 333Russellville, AR  72802Tel  479-858-4710 Stephenie PyleManager, Regulatory AssuranceArkansas Nuclear One 1CAN041404Page 2 of 2cc: Mr. Marc L. DapasRegional AdministratorU. S. Nuclear Regulatory Commission, Region IV1600 East Lamar BoulevardArlington, TX 76011-4511NRC Senior Resident InspectorArkansas Nuclear OneP.O. Box 310London, AR 72847U. S. Nuclear Regulatory CommissionAttn: Mr. Peter Bamford MS O-8B3One White Flint North 11555 Rockville PikeRockville, MD 20852 ATTACHMENT TO1CAN041404Responses to RAIs Regarding 1R24 Steam Generator Tube Inspection Report Attachment to 1CAN041404Page 1 of 19Responses to RAIs Regarding 1R24 Steam Generator Tube Inspection ReportBy letter dated October 23, 2013 (ML 13296A746), Entergy Operations, Inc. (Entergy),submitted the Arkansas Nuclear One, Unit 1 (ANO-1) Steam Generator Tube Inspection Reportfor refueling outage 1R24 to ensure compliance with ANO-1 Technical Specification (TS) 5.5.9,"Steam Generator (SG) Program." The U.S. Nuclear Regulatory Commission (NRC) staff iscurrently reviewing the submittal and has determined that the additional information listed belowis needed to complete its review:
1.Section 3.7 indicates that there is tie rod bowing in the plastic range in the first-spantie rod region of both steam generators (SGs) and that as a result there will be someresidual bowing during normal power operation. Please discuss what effects thisresidual bowing may have on normal operation of the SGs.Based on the amount of plastic deformation that currently exist and projected to exist, tubeswere plugged and stabilized to surround the affected tie rods. The gap between the tie rodsand the adjacent tubes is ~ 0.25 inches. Therefore once the amount of plastic deformationexceeds that distance, there is a potential for the tie rod to come in contact with a tube andcould potential result in mechanical wear. Therefore the affected tubes were removed fromservice by plugging and stabilizing.
2.Section 3.7 indicates that the direction of tie rod bowing in the first span for SGs Aand B are not consistent. For SG B, some of the bowing is circumferential as opposedto being all radially inward, as with SG A. Please discuss any insights on why there isa difference in the direction of bowing.The direction of the bowing is a direct result of where the tube support plates (TSPs) comein contact with the inner shroud as well as which plates and how many are affected by theinner shroud. As the component cools off, the frictional forces of the TSPs that come incontact with the inner shroud increase and cause a downward force on the tie rods. Basedon where those contacts are cause the rods to bow in different directions. This hasgenerally been consistent but can change slightly from outage to outage.3. As discussed in the telephone call on July 9, 2013 (ADAMS Accession No. ML13172A029), peripheral tubes were inspected for signs of denting to assist inidentifying locations where the tube support plates are suspected not to befreefloating. Please discuss the results of these inspections and your assessment ofthese results.The top tube support plate (15S) showed a slight circumferential progression in theperiphery along the W and or X axis as shown in the plot (red indications are the new dents(DNTs) in 1R24). The progression was not as significant as seen in prior outages.All voltages were below or near 1.0 Volts, and there was no noticeable difference in anyrepeat DNT voltage.
Attachment to 1CAN041404Page 2 of 19The circumferential extent of locking at the top TSP appears to be increasing with eachoperating cycle. The small dent analysis of the tubes in the 'drilled-only' holes of the topTSP are used to monitor this general progression of the overall mechanism associated withtie rod bowing. An increase in circumferential extent of locking may indicate thatincremental load is being applied to the tie rods (with potential consequent increase innumber of rods with bowing and/or increased magnitude of bowing). Of course, the as-inspected changes in tie rod bowing are the final measure of the progression of thepostulated mechanism.4. Figure 3.7.1 indicates that one tie rod in the first span may have been in contact witha tube during normal (hot) operating conditions. Please confirm that no tube wearwas identified in the first span region of the tube that was in contact with the tie rod.The NRC staff notes that in 1 R24 (2013 outage), tube stabilization and plugging wasperformed in tubes that were predicted to be in contact with the tie rods duringoperation (hot conditions). Please explain if this is a change in practice since the prior inspection.In the 180 day report on Figures 3.7.1 and 3.7.2, the red dots on the graphs indicate whenthat location was plugged and stabilized. Preventative plugging was started in the first in-service inspection in 1R20 for SGA and 1R23 for SGB. This practice has been performed Attachment to 1CAN041404Page 3 of 19and was continued in the last outage (1R24) to plug out to the point that would allow for fouradditional thermal cycles to prevent contact. To date there has been no tube wearassociated with tie rod bowing in either generator.5. Figure 3.7.1 indicates that the bow in 1 R23 had slightly less bow than was observedin 1R22. Please discuss any insights on condition.When the component is returned to service (normal operating temperature and pressure),the TSPs are released from the inner shroud as it expands due to thermal expansion.During the next cool down, the TSPs may adhere to the shroud at different locations andtimes which results in more or less bowing.6. Please provide a listing of the location, orientation, and measured size of all service-induced wear indications detected during the 1 R24 (2013) outage and discuss anywear indications attributed to interaction between the tube and tube support plates.This was not a code inspection so the list of TSP wear was only on those tubes near the tierods that were part of the planned scope or that were contained in the previous tube to tubewear tubes. Therefore it was not included. Tables 1 and 2 lists the tubes for SGA and SGB,respectively, that were identified based on the limited scope inspection.7. The 95th percentile growth rate in SG A appears higher in 2013 (1 R24) than it was in2011 (1 R23). In addition, the maximum growth rate observed was higher in SG B in2013 than it was in 2011. Please discuss any insights on this condition since thegrowth rate for wear tends to decrease with time. In addition, please discuss how thiscondition was factored into your operational assessment (an increasing growth ratewith time).The 1R23 operational assessment was performed using a fully probabilistic model. Sincethis was a limited scope inspection, not all tubes were equally represented across thebundle. Once through designs, tend to have higher wear in the periphery than in the innerbundle. The maximum value (12.88%) was a periphery tube which was removedconservatively due to the higher growth rate. The value still fell within the distribution of thevalues used in the probabilistic model. Since the 1R23 data was based on a 100%inspection, one would expect it to be lower since it has all of the inner tubes in thepopulation while this inspection focused on those around the tie rods and the periphery from the 9th TSP to the upper tube end.8. In Tables 3.7.5 and 3.7.6, depths are not provided in the X-probe column when twowear scars were detected by an array coil. Please clarify why the depth for each of thewear scars was not provided and discuss how the indications could have been sizedwith the array (X-) probe).The reported depth was the total depth for the multiple wear scars based on the bobbincorrelation. The indications do not reflect the locations with multiple wear scars at the sameelevation since the depth sizing was based on the bobbin correlation. For the evaluations Attachment to 1CAN041404Page 4 of 19for depth and growth, the multiple indications are conservatively treated as one indicationwith the total depth for both wear scars. X-probe data was taken on all tube-to-tube wear.This was not included in the original submittal. The following tables list those tubes withmultiple indications and the depths by X-probe:From Table 3.7.5 (SGA)
RowColumnLocationInchDepth4322818.9474322818.4965023817.1855023817.75475109817.89875109818.1457725818.8167725819.20677109817.12977109818.97681111818.33981110818.529From Table 3.7.6 (SGB)
RowColumnLocationInchDepth2263818.7782263818.3862571817.9092571817.7252572817.6882572817.8672572817.7782877818.01102877818.2073490817.4853490818.5156621818.1966621818.0157820818.1957820818.01611929719.91611929719.737 Attachment to 1CAN041404Page 5 of 19Table 1SGA TSP Wear
#RowColVolts % ThroughwallSupport Location Location 1160.12613S0.5121160.13710S0.5231170.12610S0.5541190.16810S0.5451190.11613S-0.7161230.14710S0.527240.18913S-0.6489310.271112S-0.7491010.251213S0.56101030.381713S0.53111110.431913S0.56121120.12614S-0.651311140.281210S-0.581411140.12612S-0.571511150.16810S-0.671611550.16709S0.42171210.16813S0.6181220.16813S0.581912150.2910S-0.622012150.11510S0.48211310.18913S0.532213170.211009S-0.592313170.281310S-0.672413570.17709S-0.652514190.261210S-0.672614770.211113S-0.812715800.381713S-0.792819870.241213S-0.762920890.251312S-0.793021900.522312S-0.833122920.231212S-0.793222920.321613S-0.813323850.431710S-0.763423860.732610S-0.833523940.321612S-0.833624380.15708S0.5 Attachment to 1CAN041404Page 6 of 19
#RowColVolts % ThroughwallSupport Location Location 3724830.461810S-0.83824830.251112S0.323924910.251212S-0.854025400.11508S0.454125590.251008S-0.674226990.13712S-0.7643271020.14710S-0.794431790.1408S0.414532290.18808S-0.54632290.13608S0.524733290.18808S-0.624833300.13608S0.54933310.18808S-0.685033800.16608S-0.715142220.15708S-0.625246220.16808S0.55346230.311308S-0.625446230.12608S0.55546240.2908S-0.665647210.19908S-0.625747230.2908S-0.6658471180.15814S0.285948220.17808S-0.64605110.16813S-0.556164220.2908S-0.626265210.361508S-0.626365230.2908S-0.5964651100.2807S0.4665651100.19809S-0.6666651100.22910S0.36766210.14708S-0.536866220.281208S-0.646966230.18808S-0.627066240.2908S-0.627167220.241108S-0.627267230.291308S-0.577367240.291308S-0.577467250.19908S-0.62757010.14711S0.62 Attachment to 1CAN041404Page 7 of 19
#RowColVolts % ThroughwallSupport Location Location 767110.16811S-0.4677711100.221008S0.44787210.231113S-0.5379721070.211008S-0.8180741090.221007S0.4881741090.241108S-0.7282741090.16708S0.4683741100.18905S-0.6584741100.31306S-0.6785741100.14707S0.4686741100.19908S0.4687741100.361610S-0.8188741100.221010S0.2889751080.41706S-0.6790751080.2908S-0.6591751080.291309S-0.7692751090.451906S0.4693751090.14707S0.4494751090.17808S0.469577220.19908S0.596771090.351508S-0.6997771090.281208S0.4298771090.221009S-0.7499771320.261310S-0.77100771320.442010S0.34101781310.14710S-0.751028110.1513S0.56103811110.17805S-0.6104811110.451906S-0.65105821110.15708S0.4910684220.41708S-0.5710784220.16808S0.5310884230.321408S-0.5710985210.251108S-0.5911085230.14608S0.5311186220.17808S0.511286240.211008S-0.5911387200.231108S-0.5711487210.251108S-0.62 Attachment to 1CAN041404Page 8 of 19
#RowColVolts % ThroughwallSupport Location Location 1159310.13713S0.551169410.12613S0.5511710010.12613S-0.5111810110.17913S-0.55119104230.2908S-0.59120104250.19908S-0.66121106230.241108S-0.64122106230.17808S0.53123106980.21908S-0.761241061190.552410S-0.78125107880.241108S0.48126119300.281208S-0.66127119300.12409S-0.61128119440.281307S0.46129119440.12608S-0.6130119700.15708S0.48131120780.13508S-0.68132120780.251108S0.4813312210.211110S0.5313412510.14813S0.55135127410.251108S0.46136127880.15609S0.39137127980.351713S-0.8513812810.31513S0.48139128830.291209S0.4114012990.461909S0.48141129100.12414S0.5114213020.17913S0.5314313110.12714S-0.4814413310.11613S0.514513320.13713S0.5314613320.15814S-0.5514713410.311514S-0.6214813510.18913S0.5314913510.16914S-0.59150139570.17709S-0.6215114010.181013S-0.69152140150.471910S-0.69153140160.11409S-0.64 Attachment to 1CAN041404Page 9 of 19
#RowColVolts % ThroughwallSupport Location Location 154140160.381609S0.43155141140.241009S0.46156141150.261109S0.4315714310.281414S-0.64158146470.12710S-0.7515915040.241211S-0.67160151190.17910S-0.68161151230.12713S0.28 Attachment to 1CAN041404Page 10 of 19Table 2SGB TSP Wear
#RowColVolts % ThroughwallSupport Location Location 1110.271211S-0.712140.812811S-0.693180.632311S-0.8241100.321411S-0.8551140.542111S-0.7861150.291311S-0.7371160.933011S-0.7881170.431711S-0.7591180.512011S-0.73101190.281211S-0.71111200.582211S-0.78121240.321411S-0.7513210.261111S-0.6914220.241110S0.5515220.271211S0.5316220.09514S-0.8117230.09410S0.5318240.682511S-0.8192280.391611S-0.73202310.11512S-0.7821310.341511S-0.7422310.14711S0.4623320.14710S0.5124320.872911S-0.7425330.16810S0.5526330.361511S-0.74273340.17810S0.48283350.14710S0.5729410.11510S0.5830420.11510S0.53315410.391611S-0.69325410.251111S0.41335420.16710S0.634630.1510S0.53356450.221012S0.39366460.291311S-0.69 Attachment to 1CAN041404Page 11 of 19
#RowColVolts % ThroughwallSupport Location Location 376460.321411S0.5386470.291210S0.52397490.18810S0.53407490.311311S0.5417490.12612S0.41427500.19910S0.5743810.2910S0.5544810.291311S-0.67458520.311311S-0.66468530.16710S0.57478530.261111S-0.71488540.14710S0.62498540.271212S-0.7850910.17810S0.53519580.732610S0.66529590.17810S0.55539590.441811S-0.75549590.14711S0.46559600.351510S0.57569600.331412S-0.84571020.19910S0.535810640.271211S-0.665910650.221010S0.59601120.211011S-0.69611120.16711S0.5162111413210S-0.57631210.16710S0.48641210.14711S-0.71651220.1510S0.41661220.231011S-0.716712690.18810S0.556813170.14611S-0.796913180.19810S-0.697013740.692510S-0.667113740.2910S0.467214760.391611S-0.717314770.15710S0.527415790.341410S0.647515790.62211S-0.75 Attachment to 1CAN041404Page 12 of 19
#RowColVolts % ThroughwallSupport Location Location 7615800.542110S-0.757715800.441811S-0.75781610.16811S-0.767916810.451810S0.528016810.331411S-0.75811710.371611S-0.788217840.291310S-0.78317840.41611S-0.75841810.542111S-0.788518780.411610S0.448618850.532110S-0.728719113211S-0.88819870.371510S0.58920500.1407S-0.69020510.14607S-0.689120510.31308S0.469220510.2908S-0.539320510.16709S-0.669421470.14608S0.559522620.14508S0.59622630.13508S0.489722930.211010S-0.669822930.261111S-0.71992380.913010S-0.7410023380.11408S0.4610123560.1408S0.5110223590.19808S0.531032410.391611S-0.741042510.562110S-0.781052520.231010S-0.7610625410.07308S-0.7110725720.15608S0.510826390.22906S0.481092721.183511S-0.8511027670.19808S0.5311127680.09408S0.4111228670.12408S0.5311328680.11408S0.481143110.963011S-0.85 Attachment to 1CAN041404Page 13 of 19
#RowColVolts % ThroughwallSupport Location Location 11531330.15610S-0.6911631330.391608S0.4811731340.271208S0.4811831780.231008S0.511931790.15708S0.51203210.62211S-0.7812132770.17708S0.481223310.31311S-0.8112333790.19808S0.521243410.331411S-0.7812534900.14508S0.55126371140.17811S-0.721273810.2910S0.46128381150.17810S-0.591294410.16710S0.4413044250.07208S0.53131441170.321411S-0.73132461190.261111S-0.59133461190.281213S-0.711344810.31311S0.42135481210.18811S0.57136481210.371513S-0.68137481210.341412S-0.661384910.261111S-0.74139491220.331413S-0.66140511200.18810S0.59141531210.451810S0.58142531240.1510S0.69143541250.19812S0.48144561270.19912S-0.64145581290.17812S-0.5146611300.14610S0.62147631230.16709S-0.44148641290.261110S0.59149651100.18810S0.53150661090.16808S0.55151671300.16712S0.55152671300.221013S0.5153671300.16713S-0.62 Attachment to 1CAN041404Page 14 of 19
#RowColVolts % ThroughwallSupport Location Location 154681100.17708S0.6155681310.15710S-0.48156681310.18810S0.59157681310.331413S0.48158701310.16709S-0.461597110.16712S-0.81160711320.21910S-0.57161721310.13609S-0.48162721310.251110S-0.64163721310.231011S0.66164721310.2912S0.59165731320.712510S-0.66166731320.15712S0.52167741310.231012S0.57168751320.16612S0.61697710.482011S-0.81170771320.15709S-0.52171771320.231012S0.521727910.421712S-0.761738010.31311S-0.88174811320.14609S-0.55175821310.11512S-0.5717686200.11508S-0.7817786200.11508S0.39178861090.1408S0.58179881220.231109S0.55180921290.12612S-0.52181931280.261112S-0.64182981250.15712S-0.57183991240.14612S0.59184991240.19813S0.461851001230.13612S0.571861011200.261112S0.551871011200.11513S0.53188104990.13610S0.541891101090.13614S0.619011310.351312S-0.711911141150.1513S0.51192115230.19708S-0.74 Attachment to 1CAN041404Page 15 of 19
#RowColVolts % ThroughwallSupport Location Location 1931161130.491910S0.551941161130.261111S0.5519511710.572112S-0.741961171120.321310S-0.611971171120.11511S-0.531981171120.271211S0.53199118280.1308S0.462001181110.21910S-0.552011181110.18811S0.572021181110.1513S-0.52031181110.251113S0.58204119790.2908S0.552051211060.17811S0.620612210.341312S-0.712071221050.271210S-0.642081221050.652311S0.592091221050.642312S-0.6221012310.592112S-0.7821112410.72412S-0.782121241030.441710S-0.6421312510.18611S-0.7921412510.371412S-0.7821512510.15512S0.392161251010.31312S0.5321712610.632212S-0.7821812610.31112S0.35219126990.18811S0.6220126990.17812S0.5522112710.542012S-0.78222127970.291211S-0.6223127970.391612S-0.6224127980.431711S0.55225127980.18812S-0.62226127980.261112S0.5122712810.381412S-0.76228128600.19708S0.59229128910.251112S-0.62230128910.14612S0.5523112910.572112S-0.76 Attachment to 1CAN041404Page 16 of 19
#RowColVolts % ThroughwallSupport Location Location 232129380.12408S0.55233129830.15709S0.55234129940.351412S0.5323513010.22812S-0.78236130920.17810S-0.61237130920.261112S-0.6238130930.271211S0.57239131900.291212S-0.6224013210.311212S-0.74241132890.51910S-0.63242132890.361511S0.58243132890.15712S-0.51244133870.21911S0.6245133870.351412S-0.6246133870.21913S0.53247133880.16711S0.64248133880.371512S-0.5324913410.311212S-0.7425013410.14412S0.46251134850.241010S-0.55252134850.421712S-0.57253134850.11513S0.62254135830.18811S-0.58255135830.19911S0.57256135830.311312S-0.55257135830.21913S-0.55258135830.321313S0.56259135840.311312S-0.55260135840.251113S-0.55261136810.271110S-0.55262136810.16711S-0.58263136810.371511S0.57264136810.391612S-0.6265136810.241013S-0.55266136810.351513S0.5626713710.12312S0.32268137790.21911S-0.62269137790.582213S-0.6270137800.12611S0.6 Attachment to 1CAN041404Page 17 of 19
#RowColVolts % ThroughwallSupport Location Location 271138760.361513S-0.53272138760.17812S-0.58273138770.13611S0.58274139570.13609S-0.48275139740.582212S-0.6276139740.19912S0.53277140550.19911S-0.67278140550.31313S0.53279140690.471812S-0.58280141140.15612S0.39281141540.1511S-0.48282141550.211011S-0.62283141680.241012S-0.55284141680.231013S-0.6285142640.14611S0.55286142640.16712S-0.51287142640.391612S0.6288142650.16710S-0.52289142650.15711S-0.58290142650.17813S-0.48291144520.2913S-0.53292144520.14613S0.5629314610.18611S-0.69294147410.13613S0.55295147420.17811S-0.64296147420.241114S0.4429714910.672412S-0.6429815010.21812S-0.7129915030.331412S-0.73300150280.21911S-0.66301150290.321411S-0.71302150290.231013S-0.62303150300.281212S-0.62304150300.241012S0.4630515110.391612S-0.7130615110.21910S0.4830715120.13611S-0.6730815120.72512S-0.7130915120.21912S0.46 Attachment to 1CAN041404Page 18 of 19
#RowColVolts % ThroughwallSupport Location Location 31015130.231010S0.4831115130.532012S-0.7131215130.2913S-0.6931315140.842810S0.4831415140.532011S0.4631515140.16712S-0.6931615150.451810S0.5131715150.491912S-0.7131815160.21910S0.5331915160.361512S-0.7132015170.1512S-0.7132115170.17713S0.3932215180.17810S0.5132315180.231011S-0.6932415180.441712S-0.7332515190.351410S-0.6332615190.251113S0.42327151100.231013S-0.71328151120.261112S-0.71329151120.18812S0.41330151120.12613S-0.67331151150.261111S-0.71332151150.18811S0.46333151150.852812S-0.75334151150.572112S0.41335151150.381513S-0.67336151150.371513S0.39337151160.411611S-0.69338151160.461812S-0.69339151160.21912S0.46340151160.341413S-0.71341151160.311313S0.42342151170.21911S-0.62343151170.331412S-0.68344151170.31313S-0.6345151170.281213S0.37346151180.18811S-0.62347151180.221012S-0.66348151180.471813S-0.71 Attachment to 1CAN041404Page 19 of 19
#RowColVolts % ThroughwallSupport Location Location 349151190.451811S-0.69350151190.391612S-0.66351151190.341412S0.46352151190.321313S-0.69353151200.241012S-0.59354151200.241013S-0.67355151210.461812S-0.62356151240.16712S0.53}}

Latest revision as of 08:26, 11 April 2019

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