ML15288A248

Nine Mile Point, Unit 2 - Attachment 1, Response to Request for Additional Information Regarding Post Extended Power Uprate Steam Dryer Inspection Results (Non-Proprietary) and Attachment 2, Affidavit Requesting That CDI Information Be With

ML15288A248
Person / Time
Site:	Nine Mile Point
Issue date:	10/08/2015
From:	Sterio A D Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML15288A257	List: ML15288A248
References
NMP2L 2602, TAC ME1476
Download: ML15288A248 (40)

Text

{{#Wiki_filter:IThis letter forwards proprietary information in accordance with 10 CFR 2.390. The balance ofthis letter may be considered non-proprietary upon removal of Attachment 3.~Exe~on Generation October 8, 2015NMP2L 2602ATTN: Document Control DeskU.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Nine Mile Point Nuclear Station, Unit 2Renewed Facility Operating License No. NPF-69Docket No. 50-410

References:

Response to Request for Additional Information -Nine Mile Point NuclearStation, Unit 2 -Request for Additional Information Regarding Post ExtendedPower Uprate Steam Dryer Inspection Results(1) Letter from R. Guzman (NRC) to K. Langdon (NMPNS), dated December22, 2011, Nine Mile Point Nuclear Station, Unit No. 2 -Issuance ofAmendment RE: Extended Power Uprate (TAC No. ME1476)(2) Letter from P. Swift (NMPNS) to Document Control Desk (NRC), datedJuly 28, 2014, Submittal of Post Extended Power Uprate Steam DryerInspection Results in Accordance with Operating License Condition 2.C.(20)(f) and 2.C.(20)(g) (3) Email from B. Vaidya (NRC) to T. Darling (NMPNS), dated August 13,2014, Request for Additional Information, Nine Mile Point Unit 2,Submittal of Post Extended Power Uprate Steam Dryer Inspection Results in Accordance with Operating License Condition 2.C.(20)(f) and2.C.(20)(g) (4) Letter from P. Swift (NMPNS) to Document Control Desk (NRC), datedOctober 3, 2014, Response to Request for Additional Information -NineMile Point Unit 2, Submittal of Post Extended Power Uprate Steam DryerInspection Results in Accordance with Operating License Condition 2.C.(20)(f) and 2.C.(20)(g) (5) Letter from B. Mozafari (NRC) to P. Orphanos (NMPNS), dated August 5,2015, Nine Mile Point Nuclear Station, Unit 2 -Request for Additional Information Regarding Post Extended Power Uprate Steam DryerInspection ResultsBy letter dated December 22, 2011 (Reference 1), the NRC issued Amendment No. 140 toRenewed Facility Operating License No. NPF-69 for Nine Mile Point Unit 2 (NMP2). Theamendment authorized an increase in the maximum steady-state reactor core powertlevel forNMP2 to 3,988 megawatts thermal (MWt). By letter dated July 28, 2014 (Reference 2), NineMile Point Nuclear Station (NMPNS) provided the steam dryer inspection results in accordance with NMP2 Operating License Condition 2.C.(20)(f) and 2.C.(20)(g). In Reference 3, the NRCrequested additional information regarding the results of the steam dryer inspections documented in Reference

2. NMPNS provided a response to the RAIs in Reference 4.AD12~pj(?fThis letter forwards proprietary information in accordance with 10 CFR 2.390. The balance ofthis letter may be considered non-proprietary upon removal of Attachments

3.

Response to Request for Additional Information October 8, 2015Page 2The supplemental information provided in the Attachments to this letter responds to the secondrequest for additional information (RAI) documented by letter dated August 5, 2015 (Reference 5). As indicated via email, NMPNS agreed to submit the RAI responses by October 9, 2015.Attachment 1 contains the nonproprietary responses to the RAIs. Attachment 3 contains theproprietary responses to the RAIs. Attachment 2 contains an affidavit to withhold Continuum Dynamics Inc. (CDI) proprietary information contained in Attachment 3.There are no regulatory commitments contained in this letter.Should you have any questions regarding the information in this submittal, please contactDennis Moore, Site Regulatory Assurance

Manager, at (315) 349-5219.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the dayof October, 2015.Sincerely, Alexander D. SterioDirector -Site Engineering, Nine Mile Point Nuclear StationExelon Generation

Company, LLCADS/BTVAttachments:

(1) Response to Request for Additional Information (Nonproprietary) (2) Affidavit Withholding Continuum Dynamics Inc. (CDI) Proprietary Information (3) Response to Request for Additional Information (Proprietary) cc: Regional Administrator, Region I, USNRCProject Manager, USNRCResident Inspector, USNRC Attachment 1Response to Request for Additional Information (Nonproprietary) Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Mechanical and Civil Engineering Branch (EMCB)-NMP2-MF4559-SD-First RFO Post EPU-RAI-4 The licensee has installed the bolted U-channel attached to upper dryer inner side plates connected toinner vane banks to structurally stiffen the steam dryer such that the minimum alternating stress ratio (SR-a) becomes greater than 2.0. The staff is requesting the following clarification regarding the implemented retrofit:

a. Please provide a comparison of stress ratios (SR-P and SR-a) for the 54 nodes listed in Table 17(CDI Report 14-08P, Rev. 0) for the dryer with and without the U-channel stiffener and subjectto N59 load (Drain Trap out of service).

b. For the stiffened steam dryer, please provide cumulative stress distributions for the five locations on both the hood and skirt with the SR-a.c. Explain how dryer alternating stresses due to Reactor Recirculation Pump (RRP) Vane PassingFrequency (VPF) tones are accounted for in the modified NMP2 dryer. The dryer structural modes may have shifted due to the addition of the U-channel so some may now align withVPF.Part aThe estimated stresses with and without the U-channel stiffeners for the outN59 load are reportedin Table 1. The results without the stiffeners are taken directly from Table 17 in [1]. The stressesfor the case with the stiffeners added are generated using the same method described in AppendixB of [1]. Only locations located on or near the reinforced inner side plate are shown since these arethe only locations for which the scaling technique used to estimate stresses over the full 0-250 Hzrange with U-channel stiffeners added, is valid. Recall that (see Appendix B in [1]) the unit solutionstresses with the U-channel stiffeners are only generated over the 60-130 Hz range. To estimatethe stress for the full frequency range, an adjustment factor f=S(60,130)/S(0,250) is calculated forthe model without the U-channel stiffener where S(fl,f2) is the stress intensity computed usingonly the unit solutions in the frequency interval

[fl,f2] Hz. The stress ratios with the U-channel stiffener included are then estimated by multiplying the stress ratio computed for the 60-130 Hzfrequency range, by the factor f. For locations "near" the stiffener this approach works wellbecause: (i) the 60-13 0 Hz frequency range was determined to make the largest contribution to thestresses involving the side plate and its attachment welds; and (ii) the stress ratios on these weldsand components, with the stiffener are well above the target value of 2.0 so that use of theapproximate scaling approach is acceptable. At locations farther away from the reinforced innerside plate a simple scaling is not necessarily applicable particularly if other frequencies outside the60-130 Hz interval significantly affect local stress or if the stress ratios are already near the targetvalue of 2.0 so that a more accurate analysis is required to obtain stress ratios to achieve higherprecision (i.e., on the order of ASR-a=(SR-a -2)).I(3)Page 1 of 34 Attachment 1Response to Request for Additional Information CNonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information r[(3)]]Page 2 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary)

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Dynamics, Inc. Proprietary Information Table 1. Comparison of SR-P and SR-a obtained with and without the U-channel stiffeners (see Note(1)), using the N59 load (drain trap out of service) condition.

Entry Node no stiffener with stiffener(i) SR-P SR-a SR-P SR-a1 37229 2.5 5.9 2.5 5.92 113286 3.3 3.1 3.3 2.83 37592 4.9 3.0 12.9 12.24 94143 1.5 4.9 1.4 4.15 85191 1.8 3.56 143795 1.7 4.07 113508 2.2 4.0 2.1 3.68 98968 1.8 3.29 94498 2.1 4.810 90468 2.0 3.611 101600 2.6 2.6 2.7 3.012 88639 1.8 3.013 92995 2.5 3.214 141237 2.1 3.7 2.0 3.315 89317 2.1 6.016 87784 4.0 2.617 94509 3.4 2.218 99635 2.6 2.4 2.7 2.519 99200 1.7 2.5 1.6 2.220 113554 1.7 2.9 1.7 2.921 103080 2.9 2.122 113400 3.0 3.0 2.8 2.923 95267 1.8 2.3 2.2 2.224 90786 1.4 2.425 137575 2.0 2.226 95172 2.5 6.627 91055 3.5 2.0 3.5 2.128 93488 3.1 2.929 98956 2.0 2.430 85631 1.4 2.9Note: (1) Only locations near to or involving the reinforced side plate are shown.Page 3 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Entry Node no stiffener with stiffener(1)

SR-P SR-a SR-P SR-a31 101818 2.6 2.932 98624 3.0 2.933 94514 4.1 2.734 95428 1.5 2.535 84090 2.3 2.936 99451 2.3 3.137 93451 5.2 2.838 98172 2.1 3.139 90924 3.8 3.140 100989 4.7 2.8 11.2 8.941 90926 5.2 3.342 99931 5.7 3.143 91091 1.9 3.3 1.8 2.944 88702 2.5 6.4MIN (1-44) 1.4 2.0Locations near top of inner vane bank/side plate/tie bar junction45 101861 3.1 1.8 7.4 4.946 95197 3.2 1.7 5.9 3.547 99407 2.8 2.4 3.4 3.448 98442 3.1 1.8 6.1 4.149 98444 2.9 1.8 5.6 5.050 98451 3.3 1.7 6.7 3.851 98452 2.5 1.9 4.4 5.252 99408 3.3 2.0 7.8 6.053 91240 2.6 2.1 4.3 5.5MIN (45-53) 2.5 1.7 3.4 3.4Added Real Time Node (Non Weld)54 91651I 4.6 12.4 I 5.0 5.8MIN (overall)] 1.4 1 .7.Note: (1) Only locations near to or involving the reinforced side plate are shown.Page 4 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Part 4bAs explained in Section 5.8 of [1], unit solutions with the U-channel stiffener were developed overthe frequency interval 60-130 Hz. Since the mesh and node numbering on the dryer models withand without the U-channel stiffener differ, the following approach is used to generate the PSDs andcumulative PSDs requested in the RAI. First, the node locations closest to the ones in Section 5.6 of[1] where the PSDs were produced, are identified.

Next PSDs are developed for the entirefrequency range with the steam dryer model without the U-channel stiffeners. Also, PSDs over the60-130Hz frequency range are developed with the U-channel stiffeners in place. The latter resultsare then used to overwrite those in the 60-130Hz range that were obtained without the U-channel stiffeners. Thus one has a composite PSD distribution consisting of: (i) the original dryer modelwithout U-channel stiffeners (0-60Hz and 130-250Hz), and (ii) the modified dryer model with U-channel stiffeners (60-130 Hz). Finally, the cumulative PSDs are obtained by integrating the PSDcurves.Note that to facilitate comparison between the results of Section 5.6 in [1] and the ones generated here, the same frequency shifts and stress components are plotted. Since the RAI asks for resultspertaining to load N59, the plots and limiting frequency shifts will generally differ from those inFigure 21 of [1] which were generated for the baseline N55 load. Note additionally, that in Section5.6 of [1] no nodes on the skirt were plotted. Since a location on the skirt is mentioned in the RAI,an additional location is plotted for entry 37 (node 93451) which is the location with the lowestalternating stress ratio involving the skirt identified in Table 17 of [1] (see also response to Part 4a,above). This node lies at the bottom of a weld connecting the drain channel to the skirt.For each of the six locations, the cumulative PSD curves are shown for the steam dryer with the U-channel stiffeners subject to the N59 load. For the location on the skirt, the stress without thestiffeners is also shown since it was not presented previously in [1]. In general, adding thestiffeners either reduces stresses (for locations near the reinforced inner plates) or essentially leaves them unchanged (elsewhere). Any remaining differences between the prior cumulative PSDscan be attributed: to differences in loads (N55 or Baseline in [1] and N59 in the curves shown herein Figure 1); discretization on different meshes and small, but non-zero changes in response atlocations away from the reinforced inner side plate.Page 5 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Node 101861, o, +7.5% shiftCo0qd1coE35030025020015010050050 100 150 200Frequency

[ Hz ]250Figure la. Cumulative PSD of stress at node 101861 with stiffener at limiting frequency shift.Node 91651, +2.5% shiftCo0q(UE01000800600400200050100 150Frequency [ Hz ]200250Figure lb. Cumulative PSD of stress at node 91651 with stiffener at limiting frequency shift.Page 6 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Node 94509, , +10% shift°.0~-._E0)500400300200100....... .............

.1. ........050100150200250Frequency [ Hz ]Figure ic. Cumulative PSD of stress at node 94509 with stiffener at limiting frequency shift.Node 99200, +5% shift0.oo03(UE0D45040035030025020015010050050 100 150 200Frequency [ Hz ]250Figure ld. Cumulative PSD of stress at node 99200 with stiffener at limiting frequency shift.Page 7 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Node 95267, ax +10% shift0MdqCo03(0E700600500400300200100.050 100 150 200Frequency

[ Hz ]250Figure le. Cumulative PSD of stress at node 95267 with stiffener at limiting frequency shift.Node 93451, a,' +10% shiftP4E8007006005004003002O00100050100 150Frequency [ Hz]200250Figure if. Cumulative PSD of stress response at node 93451 with & w/o stiffener at limiting frequency shift.Page 8 of 34 Attachment IResponse to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Part 4cThe original evaluation considered the effect of the U-channel stiffener over the 60-130 Hzfrequency range as this was the interval making the dominant stress contribution to high stresslocations on or near the inner side plates. Since the effect of the U-channel stiffener is localized andcontributes minimally at more distant locations it was reasoned that for frequencies outside the 60-130 Hz range, stresses could be approximately accounted for by using the stress results without theU-channel in place. Thus, for distant locations the change in stress due to the stiffener is neglected; whereas for locations near the stiffener, the stress reduction obtained by reinforcement using theU-channel is only credited over the 60-13 0 Hz range so that the final result is conservative.

A potential concern exists as to whether the VPF tone (occurring at 149 Hz) may excite the modifieddryer. The specific concerns are two fold: (i) Does the addition of the U-channel affect the stressfield at locations away from the inner plate? (ii) Has the addition of the U-channel shifted a mode ofthe inner plate into the vicinity of the 149 Hz VPF frequency raising the possibility of resonantforcing of this mode?To address these concerns the unit solution stress response due to a unit (1 psi) monopole pressureover the entrance to MSL A was calculated at 149.4 Hz both with and without the U-channel stiffener. In order to facilitate comparison between stresses, the exact same mesh and finiteelement set was used for both cases. [[However, since the node andelement numbering did not change direct comparison of stresses is easily done.The unit solution stress maps obtained with and without the U-channel stiffeners are virtually identical everywhere except near the stiffeners. In each case the maximum stress occurs at liftingrod brace; the difference between these maximum stress values is less than 1%. Since the meshesare identical the stress results can be readily subtracted from one another within ANSYS. Thus, if[a]s is the stress tensor with the stiffeners applied and [a]0 is the stress tensor without thestiffeners, one can readily form A [a] =[a]s- [a] 0.Figure 2 plots the stress intensity SI{[Aar]} obtainedby applying the stress intensity operator to the stress difference A[a]. The plot shows that exceptfor the inner plate itself and the nearby structure it is attached to, the stress differences arenegligible. No additional modes are excited away from the inner plate.Page 9 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information NODAL SOLUTION ANSYS 14.0STEP=9999 SINT (AVG)DMX =. 00146514N =.01244SMX =1956.14100 300 500Figure 2. Stress intensity SI{[Aa]}

formed form the stress difference tensor obtained from the dryerwith and without stiffeners at 149.4 Hz.Figure 3 plots the difference between the stress intensities with and without the U-channel stiffeners, ASI=SI{[a]s}-SI{[a] 0} in the vicinity of the inner side plates. The stress differences areplotted on both the upper and lower surfaces of the shell elements and indicate a maximum stressintensity increase of 571 psi. On the middle plane of the shell elements (i.e., the membrane stress)the maximum stress intensity increase is 270 psi. Note however, that these stress increases occurat locations away from the high stress welds that the stiffeners were intended to alleviate. At thoselocations (near the top of the inner side plates) the stresses are either unchanged or reduced by theaddition of the stiffeners. Page 10 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Referring to the unfiltered MSL strain gage measurement data (where VPF has not been removed)in [2] the highest pressure measurement near 149 Hz is found to occur at the upper strain gagelocation in MSL A. The pressure PSD of this signal is reproduced in Figure 4 and estimated to have a149 Hz peak of approximately 7x104 psi2/Hz. Assuming a SHz width for this peak one canestimate an RMS pressure over this interval of PRMS=[(7x10-4)x5/2]1/2 = 0.042 psi. Multiplying themaximum stress difference in the unit solution by this amount implies a change in stress of0.042x571=23.9 psi. This is the estimate of the change in stress on the dryer due to the MSLexhibiting the highest peak at 149 Hz. If all MSLs make the same contribution to the stress (aconservative assumption since the other MSLs have smaller peaks at 149 Hz), and thesecontributions are combined additively (also a conservative estimation that assumes all MSLscontributions are in phase) then the net increase in RMS stress becomesSrms = 4x0.0239 ksi = 0.1 ksi occurring at a location that currently does not experience significant stress. One can estimate the peak stress Speak from RMS stress using Speak=21/2Srms=0.14 ksi,which is 1% of the allowable stress margin (13.6 ksi). Therefore the stress change anywhere on theinner plate or its connecting components when adding back in VPF is generally negligible.

Furthermore, at the high stress locations involving the upper connections of the inner side plate thestresses are either the same as or less than those without the reinforcement U-channel so that thestress contributions from this 149 Hz frequency are conservatively bounded by the no-stiffener results.Reernce1. Continuum

Dynamics, I. (2014) Stress Re-Evaluation of Nine Mile Point Unit 2 Steam Dryer at115% CLTP. C.D.I. Report No. 14-08P (Proprietary),

July.2. Continuum

Dynamics, I. (2014) Acoustic and Low Frequency Hydrodynamic Loads at 115% CLTPTarget Power Level on Nine Mile Point Unit 2 Steam Dryer to 250 Hz Using ACM Rev. 4.1R. C.D.I.Report No. 14-09P (Proprietary),

December. Page 11 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Figure 3. Difference, ASI=SI{[a]s}-SI{[ca]

0}, between the stress intensities with and without thestiffeners. Top -stress on upper surface of shell shell top; bottom -stress on lower surface.Maximum stress increase is 571 psi.Page 12 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information NMP2: Unfiltered Data0.1MSL A UpperMSL A Lower_-o0.010.0010.0001210-5050 100 150 200Frequency (Hz)250Figure 4. PSDs of unfiltered pressure measurements at EPU at the upper and lower measurements stations of MSL A (taken from [2]).Page 13 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary)

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Dynamics, Inc. Proprietary Information EMCB-NMP2-MF4559-SD-First RFO Post EPU-RAI-5

(3) The staff has reviewed these reports and resultsfrom the reports have been used in subsequent steam dryer analyses. (3) The formal response follows.1PartaTable 1 compares the stress ratios with and without (3) for the configuration without the U-channels installed and N59 load. The locations arethe same as Table 17 in CDI stress report 14-08 [1] and indicate a minimum alternating stress ratioof SR-a= 1.2.[[IReferences

1. Continuum

Dynamics, I. (2014) Stress Re-Evaluation of Nine Mile Point Unit 2 Steam Dryer at115% CLTP. C.D.I. Report No. 14-08P (Proprietary),

July.Page 14 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Table 1. Alternating stress ratios obtained at 54 locations:

(i) with (3) Results are without U-channel stiffeners installed and for the load N59[1].Page 15 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information EMCB-NMP2-MF4559-SD-First RFO Post EPU-RAI-6

i(3) The staff is requesting thefollowing clarifications related to the modified ACM 4.1 code (ACM 4.1R code) and theassociated Main Steam Line (MSL) signals.a. Explain why the unfiltered lower MSL C strain gage PSD is so much higher than those ofMSL A, B, and D. (See Figures 3.1 a, b and 3.2 A, b in CDI Report 14-09P). Confirm thedata acquisition and calibration

settings, along with the matching of strain gages andchannel numbers.Part 6aOur review confirmed the data acquisition and calibration

settings, along with the matching ofstrain gages and channel numbers.

It may therefore be concluded that the signal contents ofMSL C lower were due to actual pressure fluctuations inside the MSL piping. In fact, FigureRAI-6.1 shows that MSL A lower exhibits peak PSD values nearly identical to MSL C lower atfrequencies below 25 Hz, not supporting the statement that the MSL C lower strain gage PSD isso much higher than the other three lower strain gage PSDs. We concur that the noise floor ofMSL C lower is higher by about a factor of two on the PSD, but have no explanation for thisdifference. NMP2: MSL Signals0.1Cl-oq0.010.0010.000110.50 50 100 150 200Frequency (Hz)250Figure RAI-6.1: Unfiltered data measured on the NMP2 MSLs at 115% CLTP conditions. Page 16 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

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b. Explain the cause(s) of the sharp (at approximately 125 Hz) peaks in the PSDs of MSL D.Part 6bFigure RAI-6.2 compares the 123.5 Hz peaks on MSL D at Nine Mile Point Unit 2 to thestandpipe excitation peaks at 151 Hz on MSL D at Quad Cities Unit 2.Figure RAI-6.2:

Comparison of peaks seen in Quad Cities Unit 2 around 151 Hz (black curve) topeaks seen in Nine Mile Point Unit 2 around 123.5 Hz (red curve). The peaks are shifted infrequency by 151 Hz for QC2 and by 123.5 Hz for NMP2. The frequency resolution is betterthan 0.02 Hz.An examination of the MSL D piping drawings at NMP2 identified numerous drain lines comingoff the MSL. Four typical drain lines are compared to the standpipe lengths of the Dresservalves at QC2 in Table RAI-6.1.Table RAI-6.1: Comparison of standpipe and drain lines between QC2 and NMP2Dimension QC2 (standpipes) NMP2 (drain lines)Pipe Diameter 5.76 inches 1.7 inchesPipe Length(s) 2.65 feet (nominal) 8.1, 10.8, 10.9, and 11.1 feetEach MSL at QC2 has two Dresser safety valves where, before the addition of acoustic sidebranches, their shear-layer-driven vortex shedding frequency was around 151 Hz. Figure RAI-6.2 was generated with higher frequency resolution than is typically done for PSD plots, so thatthree distinct peaks can be identified. These peaks can also be seen in the other three MSLsand reflect small variations about the nominal length of the field-installed standpipes as given inTable RAI-6.1. It can also be noted from the QC2 PSD that the signal increases by over threeorders of magnitude over the baseline of 0.01 psid2/Hz to 30 psid2/Hz at the largest peak.Page 17 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

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[3[]Since there was no apparent reason for excluding the peak, this signal was not filtered from theMSL data and its load was used in the dryer structural analysis. Reference

1. S. Ziada and S. Shine (1999) Strouhal Numbers of Flow-Excited Acoustic Resonance ofClosed Side Branches.

Journal of Fluids and Structures 13: 127-142.Page 18 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

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c. The iicensee is requested to confirm the labeling of the ACM 4.1 and ACM 4.1R curves inFigures C.la and C.lb to ensure that they are not interchanged.

Explain the differences in thesharp peaks near 130 Hz in the Quad Cities Unit 2 (QC2) ACM 4.1 and 4.1R simulations (P3and P12). [[Part 6cThe labeling of the ACM 4.1 and 4.1R curves in Figures C.la and C.lb is correct, referencing C.D.I. Report No. 10-09, "ACM Rev. 4.1 Methodology to Predict Full Scale Steam Dryer Loadsfrom In-Plant Measurements." [[Page 19 of 34 Attachment 1Response to Request for" Additional Information (Nonproprietary) This Document Does Not Contain Continuum

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d. Part 6d(i)(3)Page 20 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary)

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Dynamics, Inc. Proprietary information Figure RAI-6.3:

Comparison of ACM 4.1 and 4.IR predictions on the NMP2 dryer at 115%CLTP power for normal EPU operation: on the outer bank hood opposite MSL C and D (top); onthe inner bank hood opposite MSL C and D (bottom). Page 21 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, inc. Proprietary Information (ii). (3)Part 6d(ii)(3)]]Page 22 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary)

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e. [[Part GeThe filtered signals shown in Figure 3.4a to d of C.D.l. Report No. 14-09 were taken from thewrong data file. Figures 3.4a to d should have compared the unfiltered signals from Figure 3.1ato d with the filtered signals from Figure 3.3a to d, as shown in the following Figure RAI-6.4a tod.The filtered signals were used correctly as input into the ACM Rev. 4.1R analysis (defining thesteam dryer loads) and the subsequent structural analysis (defining the steam dryer stresses).

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I(3)Figure RAI-6.4a: Unfiltered and filtered data comparisons on NMP2 main steam line A at 115%CLTP target power conditions for upper (top) and lower (bottom) locations. Page 24 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Figure RAI-6.4b:

Unfiltered and filtered data comparisons on NMP2 main steam line B at 115%CLTP target power conditions for upper (top) and lower (bottom) locations. Page 25 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Figure RAI-6.4c:

Unfiltered and filtered data comparisons on NMP2 main steam line C at 115%CLTP target power conditions for upper (top) and lower (bottom) locations. Page 26 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

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[[)jFigure RAI-6.4d: Unfiltered and filtered data comparisons on NMP2 main steam line D at 115%CLTP target power conditions for upper (top) and lower (bottom) locations. Page 27 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information EMCB-NMP2-MF4559-SD-First RFO Post EPU-RAI-7

a. [[Part 7aRecent changes in plant operation have impacted the loads at 89.3 and 92.5 Hz shown in C.D.I.Report No. 14-09. These changes are the following:

89.3 Hz -RCIC Valve Closed data were previously obtained by closing the inboard MOV on theRCIC line. The isolation valves were closed during periodic surveillances and the plant enteredthe RCIC out of service LCO. Recent revisions in the surveillance procedures eliminate theneed to close the isolation valves during these periodic surveillances, reducing the frequency during which the plant is operated with the isolation valve closed. The closing of the isolation valves will occur only during periods of time where maintenance is required, with the durationrestricted to the RCIC out of service limiting condition for operation, which is 14 days.(3)]Figure RAI-7.1: Comparison of peaks seen in Quad Cities Unit 2 around 151 Hz (black curve) topeaks seen in Nine Mile Point Unit 2 around 89.3 Hz (red curve) for RCIC Valve Closed. Thepeaks are shifted in frequency by 151 Hz for QC2 and by 89.3 Hz for NMP2. The frequency resolution is better than 0.02 Hz.Page 28 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information 92.5 Hz -This condition was observed when the RCIC Drain Trap was bypassed.

Investigation into this condition determined that the RCIC drain line that connects to the RCIC steam inletcorrelates to this condition. When the drain trap is functioning such that a steady steam flowexists in the drain line, versus a standing water leg in the drain line, the signal at 92.5 Hz isreduced. The normal plant operating condition for the RCIC turbine inlet steam line has steamflow through the drain trap, which is represented as the EPU baseline steam dryer loading. Thisbaseline is considered the normal steady state EPU steam dryer load profile.(3)]]Page 29 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information (3[jAlso, with regard to the last sentence in the RAI, it has been determined that strain gagechannel 4 at the MSL A upper location should have been removed from the RCIC analysis.

Theinclusion of the signal from this channel is responsible for the additional noise seen in FigureA.2a of C.D.I. Report No. 14-09, reproduced here as Figure RAI-7.4 (top). The corrected signalis shown in Figure RAI-7.4 (bottom). The removal of this channel from MSL A upper does not impact any of the other calculations provided in C.D.I. Report No. 14-09. Figure A.la from the report shows the consistent behaviorof the MSL A upper pressure throughout power ascension. Further investigation, from TableA.1 of C.D.I. Report No. 14-09, can be seen to explain the problem. All of the data collected throughout power ascension and RCIC examination were taken in April and May 2012, with theexception of the ROIC valve closed data at 115% CLTP, taken in September 2012. By this timestrain gage channel 4 must have degraded. Reference

1. Continuum

Dynamics, Inc. (2014). Computation of Cumulative Usage Factor for the 115%CLTP Power Level at Nine Mile Point Unit 2 with the Inboard RCIC Valve Closed. C.D.I.Technical Note No. 14-04P.Page 30 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary)

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Dynamics, inc. Proprietary Information (3)]Figure RAI-7.3:

Curves for MSL B at 115% CLTP target power conditions, with RCIC drain trapout-of-service (black curves) compared with the corresponding normal EPU operation curves(red curves for data taken on 24 May 2013, blue curves for data taken on 06 August 2015). Thecurves are nearly identical except at a narrow band around the peak at 92.5 Hz in the 2013data.Page 31 of 34 Attachment 1Response to Request for Additional information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information Figure RAI-7.4:

Curves for MSL A upper with the inboard RCIC valve closed, for target powerlevels 105% CLTP (black curves), 110% CLTP (red curves), and 115% CLTP (blue curves).Top: strain gage channel 4 included in MSL A upper; bottom: strain gage channel 4 excluded inMSL A upper.Page 32 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information

b. (3)Part 7b[[)jPage 33 of 34 Attachment 1Response to Request for Additional Information (Nonproprietary)

This Document Does Not Contain Continuum

Dynamics, Inc. Proprietary Information

c. (3)Part 7cPage 34 of 34 Attachment 2Affidavit Withholding Continuum Dynamics Inc. (CD I) Proprietary Information

<z~JIg~ Continuum

Dynamics, Inc.(609) 538-0444 (609) 538-0464 fax 34 Lexington Avenue Ewing, NJ 08618-2302 AFFIDAVIT RE: C.D.J. Response to Request for Additional Information (RAI), Exelon Generation

Company, NineMile Point Nuclear Station, Unit 2 (NMP2), Post Extended Power Uprate, Steam Dryer Inspection

Results, Docket No. 50-4 10 (TAC NO. MF45 59)I, Alan J. Bilanin, being duly sworn, depose and state as follows:1. I hold the position of President and Senior Associate of Continuum

Dynamics, Inc. (hereinafter referred to as C.D.I.),

and I am authorized to make the request for withholding from PublicRecord the Information contained in the document described in Paragraph

2. This Affidavit issubmitted to the Nuclear Regulatory Commission (NRC) pursuant to 10 CFR 2.390(a)(4) basedon the fact that the attached information consists of trade secret(s) of C.D.I. and that the NRCwill receive the information from C.D.J. under privilege and in confidence.

2. The Information sought to be withheld, as transmitted to Exelon Corporation as attachment toC.D.I. Letter No. 15054 dated 25 September 2015, C.D.I. Response to Request for Additional Information (RAI), Exelon Generation

Company, Nine Mile Point Nuclear Station, Unit 2(NMP2), Post Extended Power Uprate, Steam Dryer Inspection

Results, Docket No. 50-410(TAC NO. MF4559).

The proprietary information is identified by its enclosure within pairs ofdouble square brackets ("[[ ]]"). In each case, the superscript notation (3) refers to Paragraph 3 of this affidavit that provides the basis for the proprietary determination.

3. The Information summarizes:

(a) a process or method, including supporting data and analysis, where prevention of its use byC.D.I. 's competitors without license from C.D.I. constitutes a competitive advantage overother companies; (b) Information which, if used by a competitor, would reduce his expenditure of resources orimprove his competitive position in the design, manufacture,

shipment, installation, assurance of quality, or licensing of a similar product;(c) Information which discloses patentable subject matter for which it may be desirable toobtain patent protection.

The information sought to be withheld is considered to be proprietary for the reasons set forthin paragraphs 3(a), 3(b) and 3(c) above.4. The Information has been held in confidence by C.D.I., its owner. The Information hasconsistently been held in confidence by C.D.I. and no public disclosure has been made and, it isnot available to the public. All disclosures to third parties, which have been limited, have been made pursuant to the terms and conditions contained in C.D.I.'s Nondisclosure SecrecyAgreement which must be fully executed prior to disclosure.

5. The Information is a type customarily held in confidence by C.D.I. and there is a rational basistherefore.

The Information is a type, which C.D.I. considers trade secret and is held inconfidence by C.D.I. because it constitutes a source of competitive advantage in thecompetition and performance of such work in the industry. Public disclosure of theInformation is likely to cause substantial harm to C.D.I.'s competitive position and foreclose orreduce the availability of profit-making opportunities. I declare under penalty of perjury that the foregoing affidavit and the matters stated therein are true andcorrect to be the best of my knowledge, information and belief.Executed on this -day of 2015.Alan J. BilaninContinuum

Dynamics, Inc.Subscribed and sworn before me this day: --C.enurmei//tdeotary EILEEN P BURMEISTER NOTARY PUBLICSTATE OF NEW JERSEYMy Commission Expires May 06,2017}}