ML061300441

C.D.I. Report 06-11, Rev 1, Hydrodynamic Loads on Browns Ferry, Unit 1 Steam Dryer to 200 Hz.

ML061300441
Person / Time
Site:	Browns Ferry
Issue date:	05/31/2006
From:	Bilanin A Continuum Dynamics
To:	Office of Nuclear Reactor Regulation, Tennessee Valley Authority
References
00053157, TS-418, TS-431, TVA-BFN-TS-418, TVA-BFN-TS-431 06-11
Download: ML061300441 (48)

Text

ENCLOSURE 2 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)

UNITS 1, 2, AND 3 TECHNICAL SPECIFICATIONS (TS) CHANGES TS-431 AND TS-418 -

EXTENDED POWER UPRATE (EPU) OPERATION - STEAM DRYER STRESS REPORT HYDRODYNAMIC LOADS ON BROWNS FERRY NUCLEAR UNIT 1 STEAM DRYER TO 200 HZ (NON-PROPRIETARY VERSION)

Attached is the Non-Proprietary Version of CDI Report No. 06-11, "Hydrodynamic Loads on Browns Ferry Nuclear Unit 1 Steam Dryer to 200 Hz," Revision 1.

This Document Does Not Contain General Electric Proprietary Information C.D.I. Report No. 06-11 Hydrodynamic Loads on Browns Ferry Nuclear Unit 1 Steam Dryer to 200 Hz Revision 1 Prepared by Continuum Dynamics, Inc.

34 Lexington Avenue Ewing, NJ 08618 Prepared under Purchase Order No. 00053157 for TVA / Browns Ferry Nuclear Plant Nuclear Plant Road, P. 0. Box 2000 PAB-2M Decatur, AL 35609 Approved by

( 624A ib.^Alan J. Bilanin

\ A May 2006

Executive Summary Measured pressure time-history data in the four main steam lines of an SMT model of Browns Ferry Nuclear Unit 1 (BFNI) are processed by a dynamic model of the steam delivery system to predict loads on the full-scale steam dryer. These measured data are first positioned on the four main steam lines, and then used to extract acoustic sources in the system. A validated acoustic circuit methodology is used to predict the fluctuating pressures anticipated across components of the steam dryer in the reactor vessel. This pressure loading was then provided for structural analysis to assess the structural adequacy of the steam dryer in BFNI. Rev 1 This effort provides BFN1 with a dryer dynamic load definition that comes directly from measured BFN1 SMT data and the application of a validated acoustic circuit methodology, at power levels where the pressure data were acquired.

Table of Contents Section Page Executive Summary .......................................................... . i Table of Contents ........................................................... ii I. Introduction ............................................................ 1 II. Modeling Considerations ........................................................... 2 2.1 Helmholtz Analysis ........................................................... 2 2.2 Acoustic Circuit Analysis . ................................................... 3 III. Input Pressure Data . ........................................................... 5 IV. Results................................................................................. 14 V. Error Analysis ............................ ............................... 23 VI. Conclusions........................................................................... 24 VII. References............................................................................. 25 Appendix A: SMT Dryer Comparisons ................... ........................ 26 11

I. Introduction In Spring 2005 Exelon installed new stream dryers into Quad Cities Unit 2 (QC2) and Quad Cities Unit 1. This replacement design, developed by General Electric, sought to improve dryer performance and overcome structural inadequacies identified on the original dryers, which had been in place for the last 30 years. As a means for confirming the adequacy of the steam dryer, the QC2 replacement dryer was instrumented with pressure sensors at 27 locations. These pressures formed the set of data used to validate the predictions of an acoustic circuit methodology under development by Continuum Dynamics, Inc. for several years [1]. One of the results of this benchmark exercise [2] confirmed the predictive ability of the acoustic circuit methodology for pressure loading across the dryer. This methodology, validated against the Rev 1 Exelon full scale data and identified as the Bounding Pressure model, is used in this effort.

This report applies this validated acoustic circuit methodology to the Browns Ferry Nuclear Unit 1 (BFN 1) steam dryer and main steam line geometry. SMT data obtained from the four main steam lines and the instrumented subscale dryer were used to predict pressure levels on the SMT dryer and to generate predictions of the pressure loading on the BFN1 full-scale dryer at two power levels, Original Licensed Thermal Power (OLTP) and Extended Power Uprate (EPU).

II.Modeling Considerations The acoustic circuit analysis of the BFN1 steam supply system is broken into two distinct analyses: a Helmholtz solution within the steam dome and an acoustic circuit analysis in the main steam lines. This section of the report highlights the two approaches taken here. These analyses are then coupled for an integrated solution.

2.1 Helmholtz Analysis A cross-section of the steam dome (and steam dryer) is shown below in Figure 2.1, with BFNI dimensions as shown [3]. The complex three-dimensional geometry is rendered onto a uniformly-spaced rectangular grid (with mesh spacing of approximately 1.5 inches to Rev 1 accommodate frequency from 0 to 200 Hz in full scale), and a solution, over the frequency range of interest, is obtained for the Helmholtz equation a82 p + 2 p +2a 2 p p=V2p+ 2 p=

ei e2 az a2 a2 where P is the pressure at a grid point, (ois frequency, and a is acoustic speed in steam.

i g

1- Nominal Water level

_ .0% ^

Figure 2.1. Cross-sectional description of the steam dome and dryer, with the BFNI dimensions of a' = 16.0 in, b = 16.0 in, c' = 24.0 in, c = 14.5 in, d = 17.5 in, e =

15.5 in, f = 74.0 in, g = 163.0 in, i = 97.5 in, j = 189.0 in, k = 121.0 in, and R =

125.7 in (dimensions deduced from [3] to within 1.5 inches).

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This equation is solved for incremental frequencies from 0 to 200 Hz (full scale), subject to the boundary conditions dP

- =0 dn normal to all solid surfaces (the steam dome wall and interior and exterior surfaces of the dryer),

dP c0O

-dn -P dn a normal to the nominal water level surface, and unit pressure applied to one inlet to a main steam line and zero applied to the other three.

2.2 Acoustic Circuit Analysis The Helmholtz solution within the steam dome is coupled to an acoustic circuit solution in the main steam lines. Pulsation in a single-phase compressible medium, where acoustic wavelengths are long compared to transverse dimensions (directions perpendicular to the primary flow directions), lend themselves to application of the acoustic circuit methodology. If the analysis is restricted to frequencies below 200 Hz, acoustic wavelengths are approximately 8 feet in length and wavelengths are therefore long compared to most components of interest, such as branch junctions.

Acoustic circuit analysis divides the main steam lines into elements which are each characterized, as sketched in Figure 2.2, by a length L, a cross-sectional area A, a fluid mean density p, a fluid mean flow velocity U, and a fluid mean acoustic speed a.

- A - element cross-sectional area (A)

I 11 I- L 1.1 Figure 2.2. Schematic of an element in the acoustic circuit analysis, with length L and cross-sectional area A.

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This Page Does Not Contain General Electric Proprietary Information Application of acoustic circuit methodology generates solutions for the fluctuating pressure Pn and velocity un in the nth element of the form Pn = [Ane InXn + Bneik2nXn i(Ot u - I(a + Un kln)A eiklnXn + (() +UUnk2n)Bne ik2nXn Jeict Pa2 kIn k2n where harmonic time dependence of the form el't has been assumed. The wave numbers kIn and k2 nare the two complex roots of the equation k n 22 +i n~I(÷~ z(+

o Unkn) n )-= 2 ((O +Un kn) nY~u)=0 Dna a where fn is the pipe friction factor for element n, Dn is the hydrodynamic diameter for element n, and i = Oh7 . An and B. are complex constants which are a function of frequency and are determined by satisfying continuity of pressure and mass conservation at element junctions.

The solution for pressure and velocity in the main steam lines is coupled to the Helmholtz solution for the steam dome, to predict the pressure loading on the steam dryer.

The main steam line piping geometry is summarized in Table 2.1.

Table 2.1. Main steam line lengths at BFN1, scaled from SMT lengths [4]. The main steam lines are 26 inch (ID = 24.0 in).

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This Page Does Not Contain General Electric Proprietary Information III. Input Pressure Data Microphones were mounted on the four main steam lines of the SMT, and at 18 locations on the surface of the SMT dryer. Two data sets, at Original Licensed Thermal Power (OLTP) and at Extended Power Uprate (EPU), were examined.

The main steam line pressure signals may be represented in two ways, by their minimum and maximum pressure levels, and by their PSDs as a function of frequency. Table 3.1 provides the pressure level information, while Figures 3.1 to 3.8 compare the OLTP and EPU frequency content at the eight measurement locations.

Table 3.1. Main steam line (MSL) pressure levels in the SMT for BFN1 [5].

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Figure 3.1. PSD comparison of pressure measurements on the SMT main steam line A at the upper microphone: OLTP (top) and EPU (bottom).

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(3)))1 Figure 3.2. PSD comparison of pressure measurements on the SMT main steam line A at the lower microphone: OLTP (top) and EPU (bottom).

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Figure 3.3. PSD comparison of pressure measurements on the SMT main steam line B at the upper microphone: OLTP (top) and EPU (bottom).

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Figure 3.4. PSD comparison of pressure measurements on the SMT main steam line B at the lower microphone: OLTP (top) and EPU (bottom).

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Figure 3.5. PSD comparison of pressure measurements on the SMT main steam line C at the upper microphone: OLTP (top) and EPU (bottom).

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(3)))j Figure 3.6. PSD comparison of pressure measurements on the SMT main steam line C at the lower microphone: OLTP (top) and EPU (bottom).

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Figure 3.7. PSD comparison of pressure measurements on the SMT main steam line D at the upper microphone: OLTP (top) and EPU (bottom).

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Figure 3.8. PSD comparison of pressure measurements on the SMT main steam line D at the lower microphone: OLTP (top) and EPU (bottom).

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This Page Does Not Contain General Electric Proprietary Information IV. Results The measured SMT main steam line pressure data were used to drive the validated acoustic circuit methodology for the BFN1 steam dome coupled to the main steam lines. Two calculations were undertaken at each power level provided.

1. A comparison was made between measured data on the subscale SMT dryer and predictions with the Bounded Pressure model [2] at subscale. These results are summarized in Figure 4.1, which illustrates the comparison between data and predictions for minimum and maximum pressures at the 18 microphone locations (identified in [6]

and [7]). Note that several of the microphones are located inside the dryer (Ml, M5, M8, Mll, M13, and M15) and several are on the 0°-180° centerline (M6, M7, M14, and Ml 5). Note also that the model predictions tend to match all SMT microphone data, with the exception of the 0°-1800 centerline data; it appears to be least effective in comparing against SMT data here, as the main steam line sources (located at 72°, 1080, 2520, and 2880) are farthest removed from these locations. However, it should be further noted that full-scale model comparisons on the QC2 steam dryer, at the pressure sensor closest to Rev 1 the 0°-1800 centerline (P17), shows no such under prediction [2]. It is suggested, therefore, that the SMT data may have overestimated the pressures in this region of the steam dryer, due in part to the use of a rigid steam-water boundary in SMT, and that the acoustic circuit analysis is more reasonable. Thus, no adjustment of predicted pressure at the 0°-180° region is necessary. Appendix A contains the PSD comparisons at the 18 microphones, in addition to a tabulation of the RMS comparison between predictions and measurements.

2. A prediction was made at full scale on the BFN1 dryer based on the scaling factors identified by GE [4, 5] and summarized in Table 4.1. A low resolution load, developed at the nodal locations identified in Figures 4.2 to 4.5, produces the maximum differential and RMS pressure levels across the dryer as shown in Figure 4.6. Since the highest loads are predicted on the surfaces of the outer bank hoods (and not on their edges), two sets of additional plots are shown in Figures 4.7 and 4.8 for the peak loads.

Table 4.1. Scaling factors used in converting SMT data to full scale.

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Figure 4.1. Maximum pressures measured and predicted at the 18 microphones on the SMT of the BFN1 dryer. Note the close agreement at microphones M2 and M3, and M9 and MIO, on the outside of the outer bank hoods opposite the main steam lines. The closed circles denote microphones positioned on the inside of the dryer, while the open circles denote microphones positioned along the 0°-180° dryer centerline.

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Figure 4.2. Bottom plates pressure node locations (low resolution), with pressures acting downward in the notation defined here.

16 cO I

r - -

3 4369

'3 17 411 197 15-z

II I

II Figure 4.4. Vertical plates: Pressures acting left to right on panels 6-11, 22-27, 38-43, and 50-54; acting right to left on panels 64-69, 80-85, and 94-99 (low resolution).

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F A Figure 4.5. Skirt plates: Pressure acting outward on the outer dryer 00/1800 surfaces and the skirt (low resolution).

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2 1-4 Cd

+-A r.-I (a.)49"

_4 .'.O 1.5 0 Cn C4 a V

$_4 1 9 Cn Ln EV A-4 0.5 CI'd, 0

0 20 40 60 80 100 Node Number 0.6 0.5 Cn 0.4

'-4 0.3 0.2 0.1 0

0 20 40 60 80 100 Node Number Figure 4.6. Predicted loads on the low resolution grid identified in Figures 4.2 to 4.5, as developed by the Bounding Pressure model, to 200 Hz. Low-numbered nodes are on the C-D side of the dryer, while high-numbered nodes are on the A-B side of the dryer.

20 C'0Y?3

4 3

"C 2 Cn C).4 1

U

..4

Z V) 0 Cn (a.)

__4 -1 A-4

-2

-3 0.5 1 1.5 2 2.5 3 3.5 Time (see) 1000 100 10 1

C:4 0.1 11/~

0.01 0.001 0.0001 0 50 100 150 200 Frequency (Hz)

Figure 4.7. Time history and PSD of the maximum high-resolution pressure loads predicted on the A-B side of the BFNI steam dryer at full scale. The behavior of the PSDs shown here, specifically below 125 Hz, is dependent on the conversion factors summarized in Table 4. 1.

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4 3 --- -- -- - - -- - - - - -- - - - - -- - -- --

2 ..... X]

0

-2

-4 0 0.5 1 1.5 2 2.5 3 3.5 Time (sec) 1000 I-100 --100 OLTP LT~oC-D on C- side ie---------- ---------------------- ---------- -

N EPU on C-D side

. 1- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -,-- - - - - - - -

A- - - - - - - - - - - - - - - - - - - - - - -----

C0.1 -- .. - -- ---- o 001 pH0.01 ---i- s a ' ' - -- -'-- ---' --- -----'--'--

0.0001 I,, I, I., , I 0 50 100 150 200 Frequency (Hz)

Figure 4.8. Time history and PSD of the maximum high-resolution pressure loads predicted on the C-D side of the BFN1 steam dryer at full scale. The behavior of the PSDs shown here, specifically below 125 Hz, is dependent on the conversion factors summarized in Table 4.1.

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V. Error Analysis The analysis of potential uncertainty occurring at BFN1 consists of several contributions, including the following: the uncertainty from using SMT data, the uncertainty from collecting data on the main steam lines at locations other than the locations on Quad Cities Unit 2 (QC2),

and the uncertainty in the Bounding Pressure model.

1. An uncertainty analysis of the SMT facility should be provided by GE.

2. An uncertainty analysis undertaken for Vermont Yankee [8] can be applied to the SMT data collection locations to estimate the location error of the main steam line microphones, as they were not located at their equivalent QC2 locations. That analysis would apply only to the SMT data, as TVA is expected to position their full scale data collection at the proper locations.

Scaling the position uncertainty discussed in [8] finds:

SMT Position Uncertainty 6.7%

3. An uncertainty analysis can be undertaken with regard to the Bounding Pressure model.

A comparison of the minimum and maximum pressures predicted at the external pressure transducers on QC2 (20 pressure transducers), compared to the minimum and maximum measured pressures, gives the following results:

Average Uncertainty -34.7%

One Standard Deviation 10.4%

Overall Uncertainty -24.3%

Thus, the Bounding Pressure model consistently over predicts the pressure levels measured on QC2 (including near the 0°- 1800 centerline), and no uncertainty need be applied to the results of the Bounding Pressure model as summarized in this report for BFN 1.

It should be noted that, through an extensive analysis, Exelon [9] concluded that the best estimate of the overall uncertainty for steam dryer acoustic circuit analysis methodology was that the error would range from a maximum under prediction of 3.5% to a maximum over prediction of 14.5%. These estimates are based on the use of strain gage pairs positioned on the four main steam lines at approximately 9.5 and 41.0 feet downstream of the steam dome. This analysis will be useful once TVA collects full scale data.

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VI. Conclusions The C.D.I. acoustic circuit analysis, using SMT measured data for BFN1:

a) Determines that steam dryer maximum differential pressure loads, based on the validated Bounding Pressure model, are about 2.2 psid (OLTP) and 3.6 psid (EPU), after Rev 1 converting subscale predictions to full scale.

b) Predicts that the loads on dryer components are largest for components nearest the main steam line inlets and decrease inward into the reactor vessel.

c) Determines that the validated Bounding Pressure model predicted pressures agree well with SMT data on the subscale dryer, with the exception being along the 0O-180° Rev 1 centerline, where the SMT data are believed to be conservative. This discrepancy is greatest on the skirt along the 0°-180° centerline and results from the fact that the acoustic circuit methodology incorporates acoustic radiation into the water between the skirt and the vessel. The acoustic circuit methodology predicts the QC2 skirt data conservatively and therefore it is believed that the SMT data is conservative on the skirt.

The following additional work is suggested:

• It is highly recommended that strain gages or pressure transducers be positioned at distances similar to those in Quad Cities Unit 2 (9.5 and 41.0 feet from the inside of the steam dome [2]), and that full scale data be collected and analyzed.

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VII. References

1. Continuum Dynamics, Inc. 2005. Methodology to Determine Unsteady Pressure Loading on Components in Reactor Steam Domes (Rev. 6). C.D.I. Report No. 04-09 (C.D.I. Proprietary).

2. Continuum Dynamics, Inc. 2005. Bounding Methodology to Predict Full Scall Steam Dryer Loads from In-Plant Measurements (Rev. 2). C.D.I. Report No. 05-28 (C.D.I. Proprietary).

3. Browns Ferry Unit 1 Drawings. 2006. Files: 729E229-I.tif, 729E229-2.tif, and 729E229-3.tif. BFN1 Email from G. Nelson dated 07 March 10:31:00 2006.

4. General Electric Energy, Nuclear. 2006. Transmittal of Updated Correction Factors for GE SMT BFNI Load Data. GE Letter No. GE-ERI-AEP-06-309.

5. General Electric Energy, Nuclear. 2006. Transmittal of GE Scale Model Testing Browns Ferry 1 Testing Data for CDI. GE Letter No. GE-ER1-AEP-06-304.

6. General Electric Energy, Nuclear. 2006. Revised BFNI Steam Dryer Sensor Locations and Steam Line Identification. GE Email from M. O'Connor dated 03 April 19:56:35 2006.

7. General Electric Energy, Nuclear. 2006. RE: Questions regarding Browns Ferry SMT Data.

GE Email from M. O'Connor dated 04 April 10:24:34 2006.

8. Continuum Dynamics, Inc. 2005. Vermont Yankee Instrument Position Uncertainty. Letter Report Dated 01 August 2005.

9. Exelon Nuclear Generating LLC. 2005. An Assessment of the Effects of Uncertainty in the Application of Acoustic Circuit Model Predictions to the Calculation of Stresses in the Replacement Quad Cities Units 1 and 2 Steam Dryers (Revision 0). Document No. AM-21005-008.

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This Page Does Not Contain General Electric Proprietary Information Appendix A: SMT Dryer Comparisons This appendix contains the comparisons between model predictions and pressure measurements on the SMT dryer, for both OLTP and EPU conditions. A comparison of RMS levels is given in Table A.1.

Table A. 1. Summary of RMS pressures at the two power levels examined.

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Figure A. 1. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone MI on the inside of the outer bank hood opposite main steam line C: OLTP (top) and EPU (bottom).

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Figure A.2. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M2 on the outside of the outer bank hood opposite main steam line C: OLTP (top) and EPU (bottom).

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Figure A.3. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M3 on the outside of the outer bank hood opposite main steam line D: OLTP (top) and EPU (bottom).

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Figure A.4. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M4 on the outside of the skirt between main steam lines C and D: OLTP (top) and EPU (bottom).

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Figure A.5. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M5 on the inside of the skirt between main steam lines C and D: OLTP (top) and EPU (bottom).

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Figure A.6. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M6 on the outside of the hood wall between main steam lines B and C: OLTP (top) and EPU (bottom).

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Figure A.7. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M7 on the outside of the skirt wall between main steam lines B and C: OLTP (top) and EPU (bottom).

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Figure A.8. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M8 on the inside of the skirt wall between main steam lines B and C: OLTP (top) and EPU (bottom).

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Figure A.9. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M9 on the outside of the outer bank hood opposite main steam line B: OLTP (top) and EPU (bottom).

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Figure A.10. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone MIO on the outside of the outer bank hood opposite main steam line A: OLTP (top) and EPU (bottom).

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Figure A. 11. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M 1I on the inside of the outer bank hood opposite main steam line A: OLTP (top) and EPU (bottom).

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Figure A.12. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M12 on the outside of the skirt between main steam lines A and B: OLTP (top) and EPU (bottom).

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Figure A.13. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M13 on the inside of the skirt between main steam lines A and B: OLTP (top) and EPU (bottom).

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Figure A.14. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M14 on the outside of the hood between main steam lines A and D: OLTP (top) and EPU (bottom).

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Figure A. 15. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M15 on the outside of the skirt between main steam lines A and D: OLTP (top) and EPU (bottom).

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Figure A.16. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M16 on the inside of the skirt between main steam lines A and D: OLTP (top) and EPU (bottom).

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Figure A.17. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M17 on the outside of the second bank hood opposite main steam line B: OLTP (top) and EPU (bottom).

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Figure A.18. PSD comparisons between SMT data for Browns Ferry and ACM predictions, for microphone M18 on the outside of the third bank hood opposite main steam line B: OLTP (top) and EPU (bottom).

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