ML11221A013

Attachment 3, Continuum Dynamics, Inc Technical Note No. 11-17NP, Limit Curve Analysis with ACM Rev. 4.1 for Power Ascension at Nine Mile Point Unit 2, Revision 1. (Non-Proprietary)

ML11221A013
Person / Time
Site:	Nine Mile Point
Issue date:	08/05/2011
From:	Teske M E Continuum Dynamics
To:	Document Control Desk, Office of Nuclear Reactor Regulation, Westinghouse
References
4500401845, TAC ME1476 11-17NP
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ATTACHMENT 3CONTINUUM DYNAMICS, INC TECHNICAL NOTE NO. 11-17NP,"LIMIT CURVE ANALYSIS WITH ACM REV. 4.1 FOR POWERASCENSION AT NINE MILE POINT UNIT 2," REVISION 1(NON-PROPRIETARY)Certain information, considered proprietary by Continuum Dynamics, Inc., has been deleted from thisAttachment. The deletions are identified by double square brackets.Nine Mile Point Nuclear Station, LLCAugust 5, 2011 This Document Does Not Contain Continuum Dynamics, Inc. Proprietary InformationC.D.I. Technical Note No. 1 -17NPLimit Curve Analysis with ACM Rev. 4.1 forPower Ascension at Nine Mile Point Unit 2Revision 1Prepared byContinuum Dynamics, Inc.34 Lexington AvenueEwing, NJ 08618Prepared under Purchase Order No. 4500401845 forWestinghouse Electric Company LLCNuclear Services Business Unit20 International DriveWindsor, CT 06095Approved byAlan J. BilaninPrepared byMilton E. TeskeAugust 2011 This Document Does Not Contain Continuum Dynamics, Inc. Proprietary InformationTable of ContentsSection PageT able of C ontents ..................................................................... i1. Introduction ............................................................................ 12 .A pproach ............................................................................... 23. L im it C urves ...................................................................... .... 44 .R eferences ............................................................................. 9i This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information1. IntroductionDuring power ascension of Nine Mile Point Unit 2 (NMP2), from Current LicensedThermal Power (CLTP) to Extended Power Uprate (EPU), Nine Mile Point Nuclear Station,LLC (NMPNS) is required to monitor the dryer stresses at plant power levels that have not yetbeen achieved. Limit curves provide an upper bound safeguard against the potential for dryerstresses becoming higher than allowable, by estimating the not-to-be-exceeded main steam linepressure levels. In the case of NMP2, in-plant main steam line data have been analyzed at CLTPconditions to provide steam dryer hydrodynamic loads [1]. EPU is 120% of Original LicensedThermal Power (OLTP); CLTP is 104.3% of OLTP. A finite element model stress analysis hasbeen undertaken on the CLTP loads [2]. These loads provide the basis for generation of the limitcurves to be used during NMP2 power ascension.Continuum Dynamics, Inc. (C.D.I.) has developed an acoustic circuit methodology(ACM) that determines the relationship between main steam line data and pressure on the steamdryer [3]. This methodology and the use of a finite element model analysis provide thecomputational algorithm from which dryer stresses at distinct steam dryer locations can betracked through power ascension. Limit curves allow NMPNS to limit dryer stress levels, bycomparing the main steam line pressure readings -represented in Power Spectral Density (PSD)format -with the upper bound PSD derived from existing in-plant data.This technical note summarizes the proposed approach that will be used to track theanticipated stress levels in the NMP2 steam dryer during power ascension, utilizing Rev. 4.1 ofthe ACM [3], and the options available to NMP2 should a limit curve be reached.

This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information2. ApproachThe limit curve analysis for NMP2, to be used during power ascension, is patterned afterthe approach followed by Entergy Vermont Yankee (VY) in its power uprate [4]. In the VYanalysis, two levels of steam dryer performance criteria were described: (1) a Level 1 pressurelevel based on maintaining the ASME allowable alternating stress value on the dryer, and (2) aLevel 2 pressure level based on maintaining 80% of the allowable alternating stress value on thedryer. The VY approach is summarized in [5].To develop the limit curves for NMP2, the stress levels in the dryer were calculated forthe current plant acoustic signature, at CLTP conditions, and then used to determine how muchthe acoustic signature could be increased while maintaining stress levels below the stress fatiguelimit. During power ascension, strain gage data will be converted to pressure in PSD format ateach of the eight main steam line locations, for comparison with the limit curves. The straingage data will be monitored throughout power ascension to observe the onset of discrete peaks, ifthey occur.The finite element analysis of in-plant CLTP data found a lowest alternating stress ratioof 2.83 [2] as summarized in Table 1. The minimum stress ratio includes the model bias anduncertainties for specific frequency ranges as summarized in [1]. The results of the ACM Rev.4.1 analysis (based on Quad Cities Unit 2, or QC2, in-plant data) are summarized in Table 2 (anegative bias is conservative). The additional bias and uncertainties, as identified in [6], [7], [8],[9], [10], and [11], are shown in Table 3. SRSS of the uncertainties, added to the ACM bias,results in the total uncertainties shown in Table 4. These uncertainties were applied to the finiteelement analysis, resulting in the minimum stress ratio of 2.83 for ASME Level A loadcombinations.Table 1. Peak Stress Limit Summary for ACM Rev. 4.1Peak Stress Limit ]13,600 psi (Level 1) 10,880 psi (Level 2)Minimum Stress Ratio 2.83 2.262

This Document Does Not Contain Continuum Dynamics, Inc. Proprietary InformationTable 2. Bias and uncertainty for ACM Rev. 4.1Table 3. NMP2 additional uncertainties (with references cited)(3)1[(3)]]Table 4. NMP2 total uncertainty(3)]]3 This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information3. Limit CurvesLimit curves were generated from the in-plant CLTP strain gage data reported in [1].These data were filtered across the frequency ranges shown in Table 5 to remove noise andextraneous signal content, as suggested in [12]. The resulting PSD curves for each of the eightstrain gage locations were used to develop the limit curves, shown in Figures 1 to 4. Level Ilimit curves are found by multiplying the main steam line pressure PSD base traces by the squareof the corrected limiting stress ratio (2.832 = 8.01), while the Level 2 limit curves are found bymultiplying the PSD base traces by 0.64 of the square of the corrected limiting stress ratio(recovering 80% of the limiting stress ratio, or (0.80 x 2.83)2 = 2.262 = 5.11), as PSD is related tothe square of the pressure.Table 5. Exclusion frequencies for NMP2 at CLTP conditionsFrequency Range (Hz) Exclusion Cause0.0 -2.0 Mean59.85 -60.15 EMF Frequency119.85 -120.15 EMF Frequency179.85 -180.15 EMF Frequency239.85 -240.15 EMF Frequency149.0 -149.4 Recirculation Vane Passing Frequency: 100%84.0 -84.5 Non-Coherent Electrical Source4 This Document Does Not Contain Continuum Dynamics, Inc. Proprietary InformationI[[(3)]Figure 1. Level 1 (black) and Level 2 (red) limit curves for main steam line A, comparedagainst the base curves (blue) over the frequency range of interest: A upper straingage location (top); A lower strain gage location (bottom).5 This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information(3)]]1Figure 2. Level 1 (black) and Level 2 (red) limit curves for main steam line B, comparedagainst the base curves (blue) over the frequency range of interest: B upper straingage location (top); B lower strain gage location (bottom).6 This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information(3)]]1Figure 3. Level 1 (black) and Level 2 (red) limit curves for main steam line C, comparedagainst the base curves (blue) over the frequency range of interest: C upper straingage location (top); C lower strain gage location (bottom).7 This Document Does Not Contain Continuum Dynamics, Inc. Proprietary InformationI(3)Figure 4. Level 1 (black) and Level 2 (red) limit curves for main steam line D, comparedagainst the base curves (blue) over the frequency range of interest: D upper straingage location (top); D lower strain gage location (bottom).8 This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information4. References1. Continuum Dynamics, Inc. 2010. Acoustic and Low Frequency Hydrodynamic Loads atCLTP Power Level on Nine Mile Point Unit 2 Steam Dryer to 250 Hz Using ACM Rev. 4.1(Rev. 2). C.D.I. Report No. 10-10 (Proprietary).2. Continuum Dynamics, Inc. 2011. Stress Evaluation of Nine Mile Point Unit 2 Steam DryerUsing ACM Rev. 4.1 Acoustic Loads (Rev. 0). C.D.I. Report No. 11-04 (Proprietary).3. Continuum Dynamics, Inc. 2011. ACM Rev. 4.1: Methodology to Predict Full Scale SteamDryer Loads from In-Plant Measurements (Rev. 3). C.D.I. Report No. 10-09 (Proprietary).4. Entergy Nuclear Northeast. 2006. Entergy Vermont Yankee Steam Dryer Monitoring Plan(Rev. 4). Docket 50-271. No. BVY 06-056. Dated 29 June 2006.5. State of Vermont Public Service Board. 2006. Petition of Vermont Department of PublicService for an Investigation into the Reliability of the Steam Dryer and ResultingPerformance of the Vermont Yankee Nuclear Power Station under Uprate Conditions.Docket No. 7195. Hearings held 17-18 August 2006.6. Structural Integrity Associates, Inc. 2008. Nine Mile Point Unit 2 Strain Gage UncertaintyEvaluation and Pressure Conversion Factors (Rev. 1). SIA Calculation Package No. NMP-26Q-301.7. Continuum Dynamics, Inc. 2005. Vermont Yankee Instrument Position Uncertainty. LetterReport Dated 01 August 2005.8. Exelon Nuclear Generating LLC. 2005. An Assessment of the Effects of Uncertainty in theApplication of Acoustic Circuit Model Predictions to the Calculation of Stresses in theReplacement Quad Cities Units 1 and 2 Steam Dryers (Rev. 0). Document No. AM-21005-008.9. Continuum Dynamics, Inc. 2007. Finite Element Modeling Bias and Uncertainty EstimatesDerived from the Hope Creek Unit 2 Dryer Shaker Test (Rev. 0). C.D.I. Report No. 07-27(Proprietary).10. NRC Request for Additional Information on the Hope Creek Generating Station, ExtendedPower Uprate. 2007. RAI No. 14.79.11. NRC Request for Additional Information on the Hope Creek Generating Station, ExtendedPower Uprate. 2007. RAI No. 14.110.12. Structural Integrity Associates, Inc. 2009. Nine Mile Point Unit 2 Main Steam Line StrainGage Data Reduction (Rev. 0). SIA Calculation Package No. NMP-26Q-302.9