ML14204A623

Enclosure 3, Attachment - Response to the Us NRC Request for Additional Information Relative to the Monticello Replacement Steam Dryer Accoustic/Structural Ananlyses Set #7

ML14204A623
Person / Time
Site:	Monticello
Issue date:	07/18/2014
From:	Westinghouse
To:	Office of Nuclear Reactor Regulation
Shared Package
ML14204A618	List: L-MT-14-060, Extended Power Uprate: Replacement Steam Dryer - Response to NRC Requests for Additional Information, Revised Limit Curves and Supporting Information ML14204A623
References
LMT-14-060, TAC MF3330 LTR-BWR-ENG-14-010-NP
Download: ML14204A623 (29)

Text

L-MT-14-060ENCLOSURE 3WESTINGHOUSE LETTER ATTACHMENT, LTR-BWR-ENG-14-01 0-NPRESPONSES TO THE US NRC REQUEST FOR ADDITIONAL INFORMATIONRELATIVE TO THE MONTICELLO REPLACEMENT STEAM DRYERACOUSTIC/STRUCTURAL ANALYSES SET #727 pages follow Westinghouse Non-Proprietary Class 3LTR-BWR-ENG-14-010-NPResponses to the US NRC Request for AdditionalInformation Relative to the MonticelloReplacement Steam Dryer Acoustic/StructuralAnalyses Set #7July 18, 2014Westinghouse Electric Company LLC1000 Westinghouse DriveCranberry Township, PA 16066 USA© 2014 Westinghouse Electric Company LLCAll Rights Reserved Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPREQUEST FOR ADDITIONAL INFORMATIONMECHANICAL AND CIVIL ENGINEERING BRANCH (EMCB) OF THE OFFICE OF NUCLEARREACTOR REGULATIONREGARDING MONTICELLO NUCLEAR GENERATING PLANTEXTENDED POWER UPRATE POWER ASCENSION DATA TREND EVALUATIONNORTHERN STATES POWER COMPANY -MINNESOTAMONTICELLO NUCLEAR GENERATING PLANTDOCKET NO. 50-263(TAC NO. MF3330)MNGP EPU-EMCB-RSD-RAI-120During a review of power ascension data in March and April 2014, Xcel Energy discovered mislabeling ofthe main steam line (MSL)-C leads at the Monticello Nuclear Generating Plant (MNGP). In a conferencecall on April 9, 2014, the NRC staff were informed that the leads from the upper and lower strain gaugeson MSL-C were confirmed to be erroneously reversed in 2011. Xcel Energy indicated during theconference call that the impact would be small. However, this issue could potentially impact the biaserrors and uncertainties provided in the end-to-end benchmarking report for Acoustic Circuit ModelEnhanced (ACE) 2.0 (Reference 1).The NRC staff requests the following additional information:1. Please provide a detailed technical explanation for why the changes in bias errors anduncertainties were small; when the upper and lower strain gauge signals for MNGP MSL-C wereinterchanged due to mislabeling, compared to the correct case. The explanation should addressthe entire frequency range, since the dominant dryer excitation is frequency dependent.2. Also, provide plots of the MSL-C monopole and dipole sources for the two cases, and a plot ofoverlaid or super-imposed Power Spectral Densities (PSDs) of MSL-C strain gauge signals tocompare the similarities and the differences.Reference1. Letter L-MT-13-091 from Mark Schimmel, Xcel Energy, to U.S. Regulatory CommissionDocument Control Desk, dated August 29, 2013 (ADAMS Accession No.ML13248A343): Enclosure 6 (proprietary) and Enclosure 14 (non-proprietary), WestinghouseWCAP-17716-P(NP), Revision 1, "Benchmarking of the Acoustic Circuit Enhanced Revision 2.0for the Monticello Steam Dryer Replacement Project," dated August 2013 (ADAMS AccessionNos. ML13248A353 (proprietary) and ML13248A349 (non-proprietary), respectively).I Westinghouse Non-Proprietary Class 3LTR-BVWR-ENG- 14-010-NPRESPONSEBackgroundIn April 2014, Xcel Energy identified that the main steam line (MSL)C strain gauge cableswitching performed during the 2011 refuel outage, as a corrective action in response to a cablelabeling issue, appeared to have resulted in erroneous reversal of the upstream anddownstream strain gauge cables. Numerous methods were employed to validate that the MSLCcables were incorrectly switched. A revised replacement steam dryer (RSD) acoustic-structuralanalysis has consequently been performed and is documented in this response. The revisedanalysis addresses the impact to the MSLC strain gauge signals due to the switched cables.Additionally, this response provides brief descriptions of the revisions that will be made to thepreviously submitted RSD reports as a result of the revised acoustic-structural analysis.The MSL strain gauge signals are []a,c Figure RAI-120-1 summarizes thesteps in the process which are affected by the correcting of the signals. In both cases (MSLC-2011 and MSLC-Corrected), the methods used in each step are identical; however, changingthe input MSL signals [ ]a,cFigure RAI-120-1 Summary of the Acoustic-Structural Analysis Processa,c2 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPResponse to Request 1ACE Revision 2.0 was benchmarked against]a,cTable RAI-120-1 Bias and Uncertaintya,b,cTable RAI-120-2 MNGP Total Uncertaintya,b,cIn the frequency ranges for which the MSLC upstream and downstream signals differ (seeFigure RAI-120-1),a,b,c3 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-01 0-NPResponse to Request 2Plots of the MSLC monopole and dipole sources for the two cases are presented in Figure RAI-120-8 and Figure RAI-120-9. A plot of the MSLC upstream and downstream signal PowerSpectral Densities (PSDs) is provided in Figure RAI-120-2.Detailed ResultsThis RAI response documents the portions of the acoustic-structural analysis that are affectedby switching the MSLC signals. Revisions to the previously submitted reports will be updated toinclude the changes documented herein due to the MSLC signal correction. The proprietaryand non-proprietary versions of the following reports will be updated and submitted along withthe final EPU report after power ascension to EPU is complete:WCAP-17716, Rev 1, "Benchmarking of the Acoustic Circuit Enhanced Revision 2.0 for theMonticello Steam Dryer Replacement Project."WCAP-17252, Rev 4, "Acoustic Loads Definition for the Monticello Steam Dryer ReplacementProject."WCAP-1 7549, Rev 2, "Monticello Replacement Steam Dryer Structural Evaluation for High-Cycle Acoustic Loads Using ACE."SES09-127, Rev 2, "Monticello Steam Dryer Replacement -Structural Verification of SteamDryer."The ASME qualification for the RSD will be updated to include the FIV stresses resulting fromthe correction of the MSLC signals. All ASME Section III, Subsection NG requirements are metwith the updated FIV stress values.Signal ProcessingDigital signal processing is performed to]a.c The signal processing techniques used for the CLTP and EPUsignal generation were identical to those documented and accepted in WCAP-17716-P Rev. 1.Any plots of MSL signals for MSLA, MSLB, and MSLD are unchanged. For MSLC, any plotpreviously labeled as "upstream" will now be "downstream" and vice-versa.]a,c4 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPa,b,cFigure RAI-120-2 CLTP Signal (after signal processing) -MSLC5 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPFigure RAI-120-3 Predicted EPU Signal -MSLCa,b,c6 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-01 0-NPACE Revision 2.0.1 BenchmarkinqThe ACE Revision 2.0 model was benchmarked]acTable RAI-120-3 [I a,c7]a,b,cI]ac7 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-01 0-NP-]a,b,cFigure RAI-120-4 [Figure RAI-120-5 [I axa,b,c]a,c8 Westinghouse Non-Proprietary Class 3Table RAI-120-4 Predicted RMS StrainsLTR-BWR-ENG- 14-01 0-NPa,b,c]aca,cIIIa,cII a,cBased on the above measurements, predictions, and calculations, the biases/uncertainties andtotal uncertainties for ACE Revision 2.0.1 are presented in Table RAI-120-1 and Table RAI-120-2.9 Westinghouse Non-Proprietaty Class 3LTR-BWR-ENG- 14-01 0-NP]a,ca,b,cFigure RAI-120-6 [I a,c10 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPIaxca,b,cFigure RAI-120-7 [11 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPApplication of ACE Revision 2.0.1 -Acoustic Load Definition of Monticello Steam Dryerat EPU Using Corrected MSLC SignalsIa,cFigure RAI-120-8 ACE Dipole Signal -EPU -MSL Ca,b,c12 Westinghouse Non-Proprietary Class 3LTR-B WR-ENG- 14-010-NPa,b,cFigure RAI-120-9 ACE Monopole Signal -EPU -MSL CApplication of r la -Acoustic Load Definition of Monticello SteamDryer at EPU Usina Corrected MSLC SicnalsI13 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NP]a,ca,b,cFigure RAI-120-10 []a Dipole Signal -EPU -MSLC14 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPa,b,cFigure RAI-120-11 []a Monopole Signal -EPU -MSLC15 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPStructural Evaluation for High-cycle Acoustic LoadsA high-cycle fatigue evaluation of the MNGP RSD was completed with acoustic loads generatedusing ACE Revision 2.0.1 [ ]a. The methods and techniques used inthe evaluation are identical to those submitted in WCAP-17549-P Revision 2. The finite elementmodel was identical to what was previously used.]a,cSummary of ResultsI]ac16 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPTable RAI-120-5 Summary of Results at EPU: [ ]a,ca,b,cTable RAI-120-6 Summary of Results at EPU: [a,c a,b,c17 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPa,b,caxcFigure RAI-120-12 Limiting High-Stress Locations [18 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPa,cFigure RAI-120-13 Limiting High-Stress Locations [Iac19 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-01 0-NPI a,b,cFFigure RAI-120-14 MASR [Figure RAI-120-15 MASR[]a,c. MSLC 2011 -Stress PSDa,b,c]a,c. MSLC Corrected -Stress PSD20 Westinghouse Non-Proprietary Class 3LTR-B WR-ENG- 14-01 0-NPI a,b,cFigure RAI-120-16 MASR [Figure RAI-120-17 MASR []a,c. MSLC 2011 -Stress PSDa,b,c]a,c -MSLC Corrected -Stress PSD21 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPIa,ca,b,cJa,c Submodel Maximum Detailed View (Acoustic Stress)Figure RAI-120-18 [22 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG-1 4-010-NPI]a,ca,cFigure RAI-120-19 []a,c Weld Evaluation Location23 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPMSL Limit CurvesThe method and technique used to develop the limit curves for the MNGP EPU powerascension are identical to those previously submitted in LTR-A&SA-09-32, Revision 8. For MSLA, B, and D, the shape of the upstream and downstream limit curves will be identical to thosesubmitted in LTR-A&SA-09-32, Revision 8. []a,b,c. For MSLC, the same is true except the figures previously labeled upstreamwill now be labeled as downstream and vice versa. Figure RAI-120-20 through Figure RAI-120-23 present the updated MSL limit curves for the MNGP RSD. Level 1 limit curves ensure thatthe ASME allowable alternating stress value on the RSD is not exceeded. Level 2 limit curvesensure that 80% of the allowable alternating stress value on the RSD is not exceeded. Duringpower ascension, the plant will be monitored and the PSDs will be compared to the limit curvesat each power level test condition in the EPU Power Ascension Test. The situations presentedin Table RAI-120-7 may occur depending on the magnitude of the pressure load. This processwill be repeated until the EPU power level is achieved.Table RAI-120-7 EPU Power AscensionCondition ActionPressure Load < Level 2 Increase power to the next levelPerform a stress analysis at the current powerLevel 2 < Pressure Load < Level 1 levelReduce power to the previous step,engineering evaluation, and consideration ofPressure Load > Level 1 mitigation actions24 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-01 0-NPa,b,cFigure RAI-120-20 Limit Curves -MSLAa,b,cFigure RAI-120-21 Limit Curves -MSLB25 Westinghouse Non-Proprietary Class 3LTR-BWR-ENG- 14-010-NPa,b,cFigure RAI-120-22 Limit Curves -MSLCa,b,cFigure RAI-120-23 Limit Curves -MSLD26 QF0212, Revision 5 (FP-SC-RSI-04)Page 1 of 1XcelEnergy°SHIPPING DOCUMENTNORTHERN STATES POWER -MND/B/A Xcel EnergyMonticello Nuclear Plant, 2807 W Hwy. 75, Monticello, MN 55362Date: 7-22-14 Shipping DocumentTracking Number: 15'4-Ship To:USNRC11555 Rockville PikeRockville, MD 20852-2738Attention Of: Document Control DeskCarrier: UPS -Standard Overnight RMA No:Pro I Tracking No: PO / Contract No:Packaging: Number of Packages: I Weight:Dangerous Goods/ UN/NA No: Insurance Est. ValueHazardous Materials? Required?Reason for Shipment: Overnight Shipment to USNRCDeNae Sievers -Please ensure tracking number is communicated to me -denae.sievers@xenuclear.comItem No. Qty. Unit Description Catalog IDIQ1 Envelop Submittal to NRCeRequestor: Date:By signing this shipping document you are declaring, to the best of your knowledge, that the material being shippeds incompliance with Xcel Energy Corporate Policies. Please print and sign your name legibly.SWIP Making Shipment: 6 Date: Z7Received By: Date:For will-call use onlyUse of this form as a procedural aid does not require retention as a quality record.