ML15288A248

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 Withheld

ML15288A248
Person / Time
Site:	Nine Mile Point
Issue date:	10/08/2015
From:	Sterio A 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 of this letter may be considered non-proprietary upon removal of Attachment 3.~Exe~on Generation October 8, 2015 NMP2L 2602 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Nine Mile Point Nuclear Station, Unit 2 Renewed Facility Operating License No. NPF-69 Docket No. 50-410

References:

Response to Request for Additional Information -Nine Mile Point Nuclear Station, Unit 2 -Request for Additional Information Regarding Post Extended Power Uprate Steam Dryer Inspection Results (1) Letter from R. Guzman (NRC) to K. Langdon (NMPNS), dated December 22, 2011, Nine Mile Point Nuclear Station, Unit No. 2 -Issuance of Amendment RE: Extended Power Uprate (TAC No. ME1476)(2) Letter from P. Swift (NMPNS) to Document Control Desk (NRC), dated July 28, 2014, Submittal of Post Extended Power Uprate Steam Dryer Inspection 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) and 2.C.(20)(g) (4) Letter from P. Swift (NMPNS) to Document Control Desk (NRC), dated October 3, 2014, Response to 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) 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 Dryer Inspection Results By letter dated December 22, 2011 (Reference 1), the NRC issued Amendment No. 140 to Renewed Facility Operating License No. NPF-69 for Nine Mile Point Unit 2 (NMP2). The amendment authorized an increase in the maximum steady-state reactor core powertlevel for NMP2 to 3,988 megawatts thermal (MWt). By letter dated July 28, 2014 (Reference 2), Nine Mile 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 NRC requested 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(?f This letter forwards proprietary information in accordance with 10 CFR 2.390. The balance of this letter may be considered non-proprietary upon removal of Attachments

3.

Response to Request for Additional Information October 8, 2015 Page 2 The supplemental information provided in the Attachments to this letter responds to the second request 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 the proprietary 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 contact Dennis 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 day of October, 2015.Sincerely, Alexander D. Sterio Director -Site Engineering, Nine Mile Point Nuclear Station Exelon Generation Company, LLC ADS/BTV Attachments: (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, USNRC Project Manager, USNRC Resident Inspector, USNRC Attachment 1 Response to Request for Additional Information (Nonproprietary) Attachment 1 Response 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 to inner 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 subject to 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 Passing Frequency (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 with VPF.Part a The estimated stresses with and without the U-channel stiffeners for the outN59 load are reported in Table 1. The results without the stiffeners are taken directly from Table 17 in [1]. The stresses for the case with the stiffeners added are generated using the same method described in Appendix B of [1]. Only locations located on or near the reinforced inner side plate are shown since these are the only locations for which the scaling technique used to estimate stresses over the full 0-250 Hz range with U-channel stiffeners added, is valid. Recall that (see Appendix B in [1]) the unit solution stresses with the U-channel stiffeners are only generated over the 60-130 Hz range. To estimate the stress for the full frequency range, an adjustment factor f=S(60,130)/S(0,250) is calculated for the model without the U-channel stiffener where S(fl,f2) is the stress intensity computed using only 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 Hz frequency range, by the factor f. For locations "near" the stiffener this approach works well because: (i) the 60-13 0 Hz frequency range was determined to make the largest contribution to the stresses involving the side plate and its attachment welds; and (ii) the stress ratios on these welds and components, with the stiffener are well above the target value of 2.0 so that use of the approximate scaling approach is acceptable. At locations farther away from the reinforced inner side plate a simple scaling is not necessarily applicable particularly if other frequencies outside the 60-130 Hz interval significantly affect local stress or if the stress ratios are already near the target value of 2.0 so that a more accurate analysis is required to obtain stress ratios to achieve higher precision (i.e., on the order of ASR-a=(SR-a -2)).I (3)Page 1 of 34 Attachment 1 Response to Request for Additional Information CNonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information r[(3)]]Page 2 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum 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-a 1 37229 2.5 5.9 2.5 5.9 2 113286 3.3 3.1 3.3 2.8 3 37592 4.9 3.0 12.9 12.2 4 94143 1.5 4.9 1.4 4.1 5 85191 1.8 3.5 6 143795 1.7 4.0 7 113508 2.2 4.0 2.1 3.6 8 98968 1.8 3.2 9 94498 2.1 4.8 10 90468 2.0 3.6 11 101600 2.6 2.6 2.7 3.0 12 88639 1.8 3.0 13 92995 2.5 3.2 14 141237 2.1 3.7 2.0 3.3 15 89317 2.1 6.0 16 87784 4.0 2.6 17 94509 3.4 2.2 18 99635 2.6 2.4 2.7 2.5 19 99200 1.7 2.5 1.6 2.2 20 113554 1.7 2.9 1.7 2.9 21 103080 2.9 2.1 22 113400 3.0 3.0 2.8 2.9 23 95267 1.8 2.3 2.2 2.2 24 90786 1.4 2.4 25 137575 2.0 2.2 26 95172 2.5 6.6 27 91055 3.5 2.0 3.5 2.1 28 93488 3.1 2.9 29 98956 2.0 2.4 30 85631 1.4 2.9 Note: (1) Only locations near to or involving the reinforced side plate are shown.Page 3 of 34 Attachment 1 Response 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-a 31 101818 2.6 2.9 32 98624 3.0 2.9 33 94514 4.1 2.7 34 95428 1.5 2.5 35 84090 2.3 2.9 36 99451 2.3 3.1 37 93451 5.2 2.8 38 98172 2.1 3.1 39 90924 3.8 3.1 40 100989 4.7 2.8 11.2 8.9 41 90926 5.2 3.3 42 99931 5.7 3.1 43 91091 1.9 3.3 1.8 2.9 44 88702 2.5 6.4 MIN (1-44) 1.4 2.0 Locations near top of inner vane bank/side plate/tie bar junction 45 101861 3.1 1.8 7.4 4.9 46 95197 3.2 1.7 5.9 3.5 47 99407 2.8 2.4 3.4 3.4 48 98442 3.1 1.8 6.1 4.1 49 98444 2.9 1.8 5.6 5.0 50 98451 3.3 1.7 6.7 3.8 51 98452 2.5 1.9 4.4 5.2 52 99408 3.3 2.0 7.8 6.0 53 91240 2.6 2.1 4.3 5.5 MIN (45-53) 2.5 1.7 3.4 3.4 Added Real Time Node (Non Weld)54 91651I 4.6 12.4 I 5.0 5.8 MIN (overall)] 1.4 1 .7.Note: (1) Only locations near to or involving the reinforced side plate are shown.Page 4 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Part 4b As explained in Section 5.8 of [1], unit solutions with the U-channel stiffener were developed over the frequency interval 60-130 Hz. Since the mesh and node numbering on the dryer models with and without the U-channel stiffener differ, the following approach is used to generate the PSDs and cumulative 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 entire frequency range with the steam dryer model without the U-channel stiffeners. Also, PSDs over the 60-130Hz frequency range are developed with the U-channel stiffeners in place. The latter results are 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 model without 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 PSD curves.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 results pertaining to load N59, the plots and limiting frequency shifts will generally differ from those in Figure 21 of [1] which were generated for the baseline N55 load. Note additionally, that in Section 5.6 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 lowest alternating 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 the stiffeners is also shown since it was not presented previously in [1]. In general, adding the stiffeners either reduces stresses (for locations near the reinforced inner plates) or essentially leaves them unchanged (elsewhere). Any remaining differences between the prior cumulative PSDs can be attributed: to differences in loads (N55 or Baseline in [1] and N59 in the curves shown here in Figure 1); discretization on different meshes and small, but non-zero changes in response at locations away from the reinforced inner side plate.Page 5 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Node 101861, o, +7.5% shift Co 0q d1 co E350 300 250 200 150 100 50 0 50 100 150 200 Frequency [ Hz ]250 Figure la. Cumulative PSD of stress at node 101861 with stiffener at limiting frequency shift.Node 91651, +2.5% shift Co 0q (U E 0 1000 800 600 400 200 0 50 100 150 Frequency [ Hz ]200 250 Figure lb. Cumulative PSD of stress at node 91651 with stiffener at limiting frequency shift.Page 6 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Node 94509, , +10% shift°.0~-._E 0)500 400 300 200 100....... ............. .1. ........0 50 100 150 200 250 Frequency [ Hz ]Figure ic. Cumulative PSD of stress at node 94509 with stiffener at limiting frequency shift.Node 99200, +5% shift 0.oo 03 (U E 0D 450 400 350 300 250 200 150 100 50 0 50 100 150 200 Frequency [ Hz ]250 Figure ld. Cumulative PSD of stress at node 99200 with stiffener at limiting frequency shift.Page 7 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Node 95267, ax +10% shift 0M dq Co 03 (0 E 700 600 500 400 300 200 100.050 100 150 200 Frequency [ Hz ]250 Figure le. Cumulative PSD of stress at node 95267 with stiffener at limiting frequency shift.Node 93451, a,' +10% shiftP4 E 800 700 600 500 400 300 2O00 100 0 50 100 150 Frequency [ Hz]200 250 Figure if. Cumulative PSD of stress response at node 93451 with & w/o stiffener at limiting frequency shift.Page 8 of 34 Attachment I Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Part 4c The original evaluation considered the effect of the U-channel stiffener over the 60-130 Hz frequency range as this was the interval making the dominant stress contribution to high stress locations on or near the inner side plates. Since the effect of the U-channel stiffener is localized and contributes 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 the U-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 the U-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 modified dryer. The specific concerns are two fold: (i) Does the addition of the U-channel affect the stress field at locations away from the inner plate? (ii) Has the addition of the U-channel shifted a mode of the inner plate into the vicinity of the 149 Hz VPF frequency raising the possibility of resonant forcing of this mode?To address these concerns the unit solution stress response due to a unit (1 psi) monopole pressure over 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 finite element set was used for both cases. [[However, since the node and element 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 lifting rod brace; the difference between these maximum stress values is less than 1%. Since the meshes are 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 the stiffeners, one can readily form A [a] =[a]s- [a] 0.Figure 2 plots the stress intensity SI{[Aar]} obtained by applying the stress intensity operator to the stress difference A[a]. The plot shows that except for the inner plate itself and the nearby structure it is attached to, the stress differences are negligible. No additional modes are excited away from the inner plate.Page 9 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information NODAL SOLUTION ANSYS 14.0 STEP=9999 SINT (AVG)DMX =. 00146 514N =.01244 SMX =1956.14 100 300 500 Figure 2. Stress intensity SI{[Aa]} formed form the stress difference tensor obtained from the dryer with 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 are plotted on both the upper and lower surfaces of the shell elements and indicate a maximum stress intensity 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 occur at locations away from the high stress welds that the stiffeners were intended to alleviate. At those locations (near the top of the inner side plates) the stresses are either unchanged or reduced by the addition of the stiffeners. Page 10 of 34 Attachment 1 Response 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 gage location in MSL A. The pressure PSD of this signal is reproduced in Figure 4 and estimated to have a 149 Hz peak of approximately 7x10 4 psi 2/Hz. Assuming a SHz width for this peak one can estimate an RMS pressure over this interval of PRMS=[(7x10-4)x5/2]1/2 = 0.042 psi. Multiplying the maximum stress difference in the unit solution by this amount implies a change in stress of 0.042x571=23.9 psi. This is the estimate of the change in stress on the dryer due to the MSL exhibiting the highest peak at 149 Hz. If all MSLs make the same contribution to the stress (a conservative assumption since the other MSLs have smaller peaks at 149 Hz), and these contributions are combined additively (also a conservative estimation that assumes all MSLs contributions are in phase) then the net increase in RMS stress becomes Srms = 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 the inner 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 the stresses are either the same as or less than those without the reinforcement U-channel so that the stress contributions from this 149 Hz frequency are conservatively bounded by the no-stiffener results.Reernce 1. Continuum Dynamics, I. (2014) Stress Re-Evaluation of Nine Mile Point Unit 2 Steam Dryer at 115% CLTP. C.D.I. Report No. 14-08P (Proprietary), July.2. Continuum Dynamics, I. (2014) Acoustic and Low Frequency Hydrodynamic Loads at 115% CLTP Target 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 1 Response 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 the stiffeners. 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 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information NMP2: Unfiltered Data 0.1 MSL A Upper MSL A Lower_-o 0.01 0.001 0.0001 2 10-5 0 50 100 150 200 Frequency (Hz)250 Figure 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 1 Response 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-5(3) The staff has reviewed these reports and results from the reports have been used in subsequent steam dryer analyses. (3) The formal response follows.1Parta Table 1 compares the stress ratios with and without (3) for the configuration without the U-channels installed and N59 load. The locations are the same as Table 17 in CDI stress report 14-08 [1] and indicate a minimum alternating stress ratio of SR-a= 1.2.[[I References

1. Continuum Dynamics, I. (2014) Stress Re-Evaluation of Nine Mile Point Unit 2 Steam Dryer at 115% CLTP. C.D.I. Report No. 14-08P (Proprietary), July.Page 14 of 34 Attachment 1 Response 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 1 Response 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-6i (3) The staff is requesting the following clarifications related to the modified ACM 4.1 code (ACM 4.1R code) and the associated Main Steam Line (MSL) signals.a. Explain why the unfiltered lower MSL C strain gage PSD is so much higher than those of MSL A, B, and D. (See Figures 3.1 a, b and 3.2 A, b in CDI Report 14-09P). Confirm the data acquisition and calibration settings, along with the matching of strain gages and channel numbers.Part 6a Our review confirmed the data acquisition and calibration settings, along with the matching of strain gages and channel numbers. It may therefore be concluded that the signal contents of MSL C lower were due to actual pressure fluctuations inside the MSL piping. In fact, Figure RAI-6.1 shows that MSL A lower exhibits peak PSD values nearly identical to MSL C lower at frequencies below 25 Hz, not supporting the statement that the MSL C lower strain gage PSD is so much higher than the other three lower strain gage PSDs. We concur that the noise floor of MSL C lower is higher by about a factor of two on the PSD, but have no explanation for this difference. NMP2: MSL Signals 0.1Cl-oq 0.01 0.001 0.0001 10.5 0 50 100 150 200 Frequency (Hz)250 Figure RAI-6.1: Unfiltered data measured on the NMP2 MSLs at 115% CLTP conditions. Page 16 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information

b. Explain the cause(s) of the sharp (at approximately 125 Hz) peaks in the PSDs of MSL D.Part 6b Figure RAI-6.2 compares the 123.5 Hz peaks on MSL D at Nine Mile Point Unit 2 to the standpipe 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) to peaks seen in Nine Mile Point Unit 2 around 123.5 Hz (red curve). The peaks are shifted in frequency by 151 Hz for QC2 and by 123.5 Hz for NMP2. The frequency resolution is better than 0.02 Hz.An examination of the MSL D piping drawings at NMP2 identified numerous drain lines coming off the MSL. Four typical drain lines are compared to the standpipe lengths of the Dresser valves at QC2 in Table RAI-6.1.Table RAI-6.1: Comparison of standpipe and drain lines between QC2 and NMP2 Dimension QC2 (standpipes)

NMP2 (drain lines)Pipe Diameter 5.76 inches 1.7 inches Pipe Length(s) 2.65 feet (nominal) 8.1, 10.8, 10.9, and 11.1 feet Each MSL at QC2 has two Dresser safety valves where, before the addition of acoustic side branches, 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 that three distinct peaks can be identified. These peaks can also be seen in the other three MSLs and reflect small variations about the nominal length of the field-installed standpipes as given in Table RAI-6.1. It can also be noted from the QC2 PSD that the signal increases by over three orders of magnitude over the baseline of 0.01 psid 2/Hz to 30 psid 2/Hz at the largest peak.Page 17 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information [3[]Since there was no apparent reason for excluding the peak, this signal was not filtered from the MSL 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 of Closed Side Branches. Journal of Fluids and Structures 13: 127-142.Page 18 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information

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

Explain the differences in the sharp peaks near 130 Hz in the Quad Cities Unit 2 (QC2) ACM 4.1 and 4.1R simulations (P3 and P12). [[Part 6c The 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 Loads from In-Plant Measurements." [[Page 19 of 34 Attachment 1 Response to Request for" Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information

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

This Document Does Not Contain Continuum 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); on the inner bank hood opposite MSL C and D (bottom).Page 21 of 34 Attachment 1 Response 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 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information

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

Page 23 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information 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 1 Response 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 1 Response 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 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information [[)j Figure 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 1 Response 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 7a Recent 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 the RCIC line. The isolation valves were closed during periodic surveillances and the plant entered the RCIC out of service LCO. Recent revisions in the surveillance procedures eliminate the need 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 duration restricted 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) to peaks seen in Nine Mile Point Unit 2 around 89.3 Hz (red curve) for RCIC Valve Closed. The peaks 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 1 Response 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 inlet correlates to this condition. When the drain trap is functioning such that a steady steam flow exists in the drain line, versus a standing water leg in the drain line, the signal at 92.5 Hz is reduced. The normal plant operating condition for the RCIC turbine inlet steam line has steam flow through the drain trap, which is represented as the EPU baseline steam dryer loading. This baseline is considered the normal steady state EPU steam dryer load profile.(3)]]Page 29 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information (3[j Also, with regard to the last sentence in the RAI, it has been determined that strain gage channel 4 at the MSL A upper location should have been removed from the RCIC analysis. The inclusion of the signal from this channel is responsible for the additional noise seen in Figure A.2a of C.D.I. Report No. 14-09, reproduced here as Figure RAI-7.4 (top). The corrected signal is 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 behavior of the MSL A upper pressure throughout power ascension. Further investigation, from Table A.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 the exception of the ROIC valve closed data at 115% CLTP, taken in September 2012. By this time strain 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 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, inc. Proprietary Information (3)]Figure RAI-7.3: Curves for MSL B at 115% CLTP target power conditions, with RCIC drain trap out-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). The curves are nearly identical except at a narrow band around the peak at 92.5 Hz in the 2013 data.Page 31 of 34 Attachment 1 Response 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 power levels 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 in MSL A upper.Page 32 of 34 Attachment 1 Response to Request for Additional Information (Nonproprietary) This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information

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

This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information

c. (3)Part 7c Page 34 of 34 Attachment 2 Affidavit 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, Nine Mile 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 Public Record the Information contained in the document described in Paragraph

2. This Affidavit is submitted to the Nuclear Regulatory Commission (NRC) pursuant to 10 CFR 2.390(a)(4) based on the fact that the attached information consists of trade secret(s) of C.D.I. and that the NRC will 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 to C.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 of double 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 by C.D.I. 's competitors without license from C.D.I. constitutes a competitive advantage over other companies;(b) Information which, if used by a competitor, would reduce his expenditure of resources or improve 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 to obtain patent protection.

The information sought to be withheld is considered to be proprietary for the reasons set forth in 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 has consistently been held in confidence by C.D.I. and no public disclosure has been made and, it is not 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 Secrecy Agreement 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 basis therefore.

The Information is a type, which C.D.I. considers trade secret and is held in confidence by C.D.I. because it constitutes a source of competitive advantage in the competition and performance of such work in the industry. Public disclosure of the Information is likely to cause substantial harm to C.D.I.'s competitive position and foreclose or reduce the availability of profit-making opportunities. I declare under penalty of perjury that the foregoing affidavit and the matters stated therein are true and correct to be the best of my knowledge, information and belief.Executed on this -day of 2015.Alan J. Bilanin Continuum Dynamics, Inc.Subscribed and sworn before me this day: --C.enurmei//tdeotary EILEEN P BURMEISTER NOTARY PUBLIC STATE OF NEW JERSEY My Commission Expires May 06,2017}}