ML092440375
| ML092440375 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 08/31/2009 |
| From: | Teske M Continuum Dynamics |
| To: | Office of Nuclear Reactor Regulation |
| References | |
| C.D.I. Report No. 09-22NP, Rev 0 | |
| Download: ML092440375 (46) | |
Text
ENCLOSURE7 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT I TECHNICAL SPECIFICATIONS (TS) CHANGE TS-431 EXTENDED POWER UPRATE (EPU)
CDI REPORT NO. 09-22NP, "ACOUSTIC AND LOW FREQUENCY HYDRODYNAMIC LOADS AT CLTP POWER LEVEL TO 110% OLTP POWER LEVEL ON BROWNS FERRY NUCLEAR UNIT I STEAM DRYER TO 250 HZ," REVISION 0 (NON-PROPRIETARY VERSION)
Attached is the non-proprietary version of CDI Report No. 09-22NP, "Acoustic and Low Frequency Hydrodynamic Loads at CLTP Power Level to 110% OLTP Power Level on Browns Ferry Nuclear Unit 1 Steam Dryer to 250 Hz."
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information C.D.I. Report No. 09-22NP Acoustic and Low Frequency Hydrodynamic Loads at CLTP Power Level to 110%
OLTP Power Level on Browns Ferry Nuclear Unit 1 Steam Dryer to 250 Hz Revision 0 Prepared by Continuum Dynamics, Inc.
34 Lexington Avenue Ewing, NJ 08618 Prepared under Purchase Order No. 00077408 for TVA / Browns Ferry Nuclear Plant Nuclear Plant Road, P. 0. Box 2000 PAB-2M Decatur, AL 35609 Approved by waqA N,
ý3dolo"A Alan J. Bilanin Prepared by Milton E. Teske f
August 2009
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Executive Summary Measured strain gage time-history data in the four main steam lines at Browns Ferry Nuclear Unit 1 (BFN1) were processed by a dynamic model of the steam delivery system to predict loads on the full-scale steam dryer.
These measured data were first converted to pressures, then positioned on the four main steam lines and used to extract acoustic sources in the system.
A validated acoustic circuit methodology was used to predict the fluctuating pressures anticipated across components of the steam dryer in the reactor vessel. The acoustic circuit methodology included a low frequency hydrodynamic contribution, in addition to an acoustic contribution at all frequencies. This pressure loading was then provided for structural analysis to assess the structural adequacy of the steam dryer in BFN1.
This effort provides BFNl with a dryer dynamic load definition that comes directly from measured BFN1 full-scale data and the application of a validated acoustic circuit methodology, at a power level where data were acquired.
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Table of Contents Section Page Executive Summary..................................................................
i T able of C ontents.....................................................................
ii
- 1. Introduction............................................................................
1
- 2. Modeling Considerations............................................................
2 2.1 Helmholtz Analysis...........................................................
2 2.2 Acoustic Circuit Analysis....................................................
3 2.3 Low Frequency Contribution................................................
4
- 3. Input Pressure Data..................................................................
5 4. R esu lts.................................................................................
13
- 5. Uncertainty Analysis..............................................................
20
- 6. Bump-Up Factors for 110% OLTP Power.......................................
22
- 7. C onclusions...........................................................................
24
- 8. R eferences............................................................................
25 ii
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 1. 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. (C.D.I.) 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, with the inclusion of a low frequency hydrodynamic load.
This methodology, validated against the Exelon full-scale data and identified as the Modified Bounding Pressure model, is used in the effort discussed herein.
This report applies this validated methodology to the Browns Ferry Nuclear Unit 1 (BFN1) steam dryer and main steam line geometry. Strain gage data obtained from the four main steam lines were used to predict pressure levels on the BFN1 full-scale dryer at Current Licensed Thermal Power-(CLTP). In addition, bump-up factors, obtained from subscale test data
[3], were used to modify the CLTP strain gage data to predict the pressure levels on the BFN1 full-scale dryer at 110% of Original Licensed Thermal Power (OLTP).
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 2. 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 BFN1 dimensions as shown [4]. The complex three-dimensional geometry is rendered onto a uniformly-spaced rectangular grid (with mesh spacing of approximately 1.5 inches to accommodate frequency from 0 to 250 Hz in full scale), and a solution, over the frequency range of interest, is obtained for the Helmholtz equation a2p a 2 p a2p 02 V
2
+__
+
+
Vp+
wX2 P i
Y2 prsu Z2 a a 2 p
i where P is the pressure at a grid point, o) is frequency, and a is acoustic speed in steam.
R i
e f
i g
I k
Nominal Water level Figure2.1. Cross-sectional description of the steam dome and dryer, with the BFN1 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 [4] to within 1.5 inches).
2
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information This equation is solved for incremental frequencies from 0 to 250 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 iw Oc-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 250 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 -
u,-, 01
)
I I
I L
I Figure 2.2.
Schematic of an element in the acoustic circuit analysis, with length L and cross-sectional area A.
3
This Document Does Not Contain Continuum Dynamics, Inc. 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 iklnxn
+Bneik2nXn Ji°t Un L((O+Unkln) Ane ikInXn
+ + Unk2 n ) Bne ik2nXn ei(Ot where harmonic time dependence of the form e iot has been assumed. The wave numbers k 1n and k2n are the two complex roots of the equation kn 2 +i 2 ((+Unk)-_
U nk
=0 Dna a
where fn is the pipe friction factor for element n, Dn is the hydrodynamic diameter for element n, and i = r-i1. An and Bn 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 in 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. Main steam line diameter is 26 inch (ID = 24.0 in).
Main Steam Line Length to First Length to Second Strain Gage Strain Gage Measurement (ft)
Measurement (ft)
A 9.5 34.5 B
9.5 34.5 C
10.0 34.5 D
9.5 34.5 2.3 Low Frequency Contribution
((
(3)))
4
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 3. Input Pressure Data Strain gages were mounted on the four main steam lines of BFN1. Two data sets were examined in this analysis. The first data set recorded the strain at Current Licensed Thermal Power (100% power level or CLTP), and the second data set recorded the strain at near-zero voltage on the strain gages (EIC noise) at CLTP. The data were provided in the following files:
Data File Name Power Level Voltage 20070608155619 100%
10.0 V 20070608155258 100%
0.01 V (EIC)
The strain gage signals were converted to pressures by the use of the conversion factors provided in [5] and summarized in Table 3.1.
Exclusion frequencies were used to remove extraneous signals, as also identified in [5] and subsequent emails, and summarized in Table 3.2.
The electrical noise was removed by applying the function PS(
0)) = PSN ((0)1 -
Ps N(w) I where Ps(co) is the CLTP signal PSN(0) corrected for electrical noise PN(O), computed as a function of frequency o, and IPN(CO)/PsN(aO)I can be no larger than 1.0. These signals were further processed by the coherence factor and mean filtering as described in [2]. Coherence at CLTP is shown in Figure 3.1.
The resulting main steam line pressure signals may be represented in two ways, by their minimum and maximum pressure levels, and by their PSDs. Table 3.3 provides the pressure level information, after removal of EIC and exclusion filtering, while Figures 3.2 to 3.5 compare the frequency content at the eight measurement locations. The frequency content around 218 Hz has been removed from the signals plotted here, in anticipation of the use of inserts in the blank standpipes on main steam lines A and D [3] to mitigate this load.
5
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Table 3.1. Conversion factors from strain to pressure [5]. Channels are averaged to give the average strain.
Strain to Pressure Channel Channel Channel Channel (psid/ strain)
Number Number Number Number MSL A Upper 2.997 1
2 3
4 MSL A Lower 3.027 5
6 7
8 MSL B Upper 3.034 9
10 11 12 MSL B Lower 2.993 13 14 15 16 MSL C Upper 2.912 17 18 19 20 MSL C Lower 2.962 21 22 23 24 MSL D Upper 2.959 25 26 27 28 MSL D Lower 3.007 29 30 31 32 Table 3.2. Exclusion frequencies for BFN1 strain gage data, as suggested in [5]
emails. VFD = variable frequency drive. Recirc = recirculation pumps.
and subsequent Frequency Interval (Hz)
Exclusion Cause 0-2 Mean 59.8 - 60.2 Line Noise 119.9 - 120.1 Line Noise 179.8 - 180.2 Line Noise 239.9 - 240.1 Line Noise 51.3-51.7 VFD (Ix) 127.0 - 128.5 Recirc Pumps A, B Speed (5x) 217.9 - 219.6 Standpipe Excitation Table 3.3. Main steam line (MSL) pressure levels in BFN1.
Minimum Maximum RMS Pressure (psid)
Pressure (psid)
Pressure (psid)
MSL A Upper
-1.82 1.95 0.43 MSL A Lower
-1.90 2.11 0.46 MSL B Upper
-1.92 2.34 0.47 MSL B Lower
-2.06 2.19 0.51 MSL C Upper
-2.17 2.42 0.53 MSL C Lower
-2.62 2.39 0.58 MSL D Upper
-2.08 2.09 0.51 MSL D Lower
-1.93 2.25 0.46 6
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information BFNI: MSL A C.)
0U 1
0.8 0.6 0.4 0.2 0 0 50 100 150 200 Frequency (Hz) 250 BFNI: MSL B 0
U 1
0.8 0.6 0.4 0.2 0
0 50 100 150 200 Frequency (Hz) 250 Figure 3.1a. Coherence between the upper and lower strain gage readings at BFNI: main steam line A (top); main steam line B (bottom).
7
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information BFNI: MSL C 0
I-U 1
0.8 0.6 0.4 0.2 0
1 0.8 0.6 0.4 0.2 0
0 50 100 150 200 Frequency (Hz) 250 BFNI: MSL D 0
0 0
0 0
U 0
50 100 150 200 Frequency (Hz) 250 Figure 3. lb. Coherence between the upper and lower strain gage readings at BFN 1: main steam line C (top); main steam line D (bottom).
8
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information BFNI: MSL A Upper 0.1 N
c-I P-4 0.01 0.001 0.0001 10.5 10-6 0.1 0
50 100 150 200 Frequency (Hz) 250 BFNI: MSL A Lower Nl 0.01 0.001 0.0001 10.5 10-6 0
50 100 150 200 Frequency (Hz) 250 Figure 3.2.
PSD comparison of pressure measurements on main steam line A at strain gage locations upper (top) and lower (bottom).
9
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information 0.1 N
z' 0.01 0.001 0.0001 10-5 BFN1: MSL B Upper II i
I I
I 1
1 F
.I I I
I.
I 10-6 0
50 100 Frequency 150 (Hz) 200 250 BFNI: MSL B Lower 0.1 N
Cl 0.01 0.001 0.0001 10-5 10-6 0
50 100 150 200 Frequency (Hz) 250 Figure 3.3. PSD comparison of pressure measurements on main steam line B at strain gage locations upper (top) and lower (bottom).
10
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information BFNI: MSL C Upper 0.1 N
Cl 0.01 0.001 0.0001 10-5
\\ A V
VV 10-6 0
50 100 Frequency 150 (Hz) 200 250 BFNI: MSL C Lower 0.1 N
Cl z-
°,17,$
rA*
0.01 0.001 0.0001 10.5 10.6 0
50 100 150 200 Frequency (Hz) 250 Figure 3.4.
PSD comparison of pressure measurements on main steam line C at strain gage locations upper (top) and lower (bottom).
11
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information BFNI: MSL D Upper 0.1 N
ClV 0.01 0.001 0.0001 10-5 10-6 0.1 0
50 100 150 200 Frequency (Hz) 250 BFNI: MSL D Lower N
Cl 0.01 0.001 0.0001 10-5 10-6 0
50 100 150 200 Frequency (Hz) 250 Figure 3.5. PSD comparison of pressure measurements on main steam line D at strain gage locations upper (top) and lower (bottom).
12
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 4. Results The measured 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 to make a pressure load prediction on the BFN1 dryer. A low resolution load, developed at the nodal locations identified in Figures 4.1 to 4.4, produces the maximum differential and RMS pressure levels across the dryer as shown in Figure 4.5. PSDs of the peak loads on either side of the dryer are shown in Figure 4.6.
13
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Figure 4.1.
Bottom plates pressure node locations (low resolution), with pressures acting downward in the notation defined here.
14
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information 17 S10
__ 10 "9,
161 26 S
1\\Q5 1125 Figure 4.2. Top plates pressure node locations (low resolution), with pressures acting downward in the notation defined here.
15
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Figure 4.3.
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).
16
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information 4
18-34 6
Figure 4.4.
Skirt plates: Pressure acting outward on the outer dryer 0'/ 1800 surfaces and the skirt (low resolution).
17
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
[II (3)]
Figure 4.5.
Predicted loads on the low resolution grid identified in Figures 4.1 to 4.4, as developed by the Modified Bounding Pressure model, to 250 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.
18
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information (3)))
Figure 4.6. PSD of the maximum pressure loads predicted on the C-D side of the BFNl dryer (top) and A-B side of the BFN I dryer (bottom).
19
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 5. Uncertainty Analysis The analysis of potential uncertainty occurring at BFN1 consists of several contributions, including 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 Modified Bounding Pressure model. QC2 dryer data at Original Licensed Thermal Power (OLTP) conditions were used to generate an uncertainty analysis of the Acoustic Circuit Methodology (ACM) [2] for BFN 1.
The approach taken for bias and uncertainty is similar to that used by Vermont Yankee for power uprate [6].
In this analysis, six "averaged pressures" are examined on the instrumented replacement dryer at QC2: averaging pressure sensors P1, P2, and P3; P4, P5, and P6; P7, P8, and P9; P10, Pll, and P12; P18 and P20; and P19 and P21. These pressure sensors were all on the outer bank hoods of the dryer, and the groups are comprised of sensors located vertically above or below each other.
Bias is computed by taking the difference between the measured and predicted RMS pressure values for the six "averaged pressures", and dividing the mean of this difference by the mean of the predicted RMS. RMS is computed by integrating the PSD across the frequency range of interest and taking the square root 1
1 I (RMSmeasured - RMSpredicted)
BIAS-N RMSprNdicted (5.1) where RMSmeasurcd is the RMS of the measured data and RMSprcdictcd is the RMS of the predicted data. Summations are over the number of "averaged pressures", or N = 6.
Uncertainty is defined as the fraction computed by the standard deviation I1 I (RMSmeasured -
RMSpredicted )2 UNCERTAINTY =
1 (5.2)
N Mpredicted ACM bias and uncertainty results are compiled for specified frequency ranges of interest, as directed by [7, 8] and summarized in Table 5.1.
Other random uncertainties, specific to BFN1, are summarized in Table 5.2 and are typically combined with the ACM results by SRSS methods to determine an overall uncertainty for BFN 1.
20
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Table 5.1. BFN 1 bias and uncertainty for specified frequency intervals. A negative bias indicates that the ACM overpredicts the QC2 data in that interval.
1r (3)))1 Table 5.2. Bias and uncertainty contributions to total uncertainty for BFN 1 plant data.
Er (3)))
21
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 6. Bump-Up Factors for 110% OLTP Power Subscale testing [3] provides the data with which to develop bump-up factors that relate unsteady main steam line pressures at CLTP conditions to those anticipated at 110% OLTP power. This bump-up factor, for each strain gage location, is applied to full-scale CLTP strain gage data collected on the main steam lines to obtain an estimate of the full-scale 110% OLTP power strain gage data near the standpipe/valve excitation frequency expected. A velocity-squared bump-up factor is used when removed from the excitation frequency. The 110% OLTP power strain gage data is then used to estimate steam dryer stresses at this power level, using the acoustic circuit model for dryer loads and a finite element model of the dryer for stress predictions.
The selected subscale tests are identified in Table 6.1.
The bump-up factor is calculated as a function of frequency (averaging the two CLTP data results), converted from subscale to full scale, with the equation Bump-Up Factor =
PSD 110 (6.1)
- PSDCLTP and involves dividing the 110% OLTP PSD at each frequency by the CLTP PSD at that frequency, and taking the square root. This equation is used for each of the eight strain gage locations in the frequency interval from 100 Hz to 120 Hz, thereby encompassing the anticipated standpipe/valve excitation frequency interval. Outside this interval, a velocity-squared bump-up factor of 1.10, based on anticipated and actual in-plant flow rate at BFN 1, is used. The resulting bump-up factors are plotted in Figure 6.1.
The bump-up factor at each strain gage location is used to multiply the strain gage readings at that location in the plant at CLTP conditions, on a frequency-by-frequency basis, to obtain the estimated main steam line strain gage readings at that location in the plant at 110%
OLTP power. The subsequent dryer loads developed from the acoustic circuit model would be provided to a finite element model of the dryer for stress predictions at 110% OLTP power.
22
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Table 6.1. Summary of one-eighth scale tests used to develop bump-up factors.
BFN1 File Names [3]
CLTP bl-f491-123 bl-f491-124 110% Power bl-f491-121 I((
(3)))
Figure 6.1.
Bump-up factors developed from BFN1 subscale data for 110% OLTP power. The eight locations are shown by the eight pressure transducer identifiers.
23
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 7. Conclusions The C.D.I. acoustic circuit analysis, using full-scale measured data for BFNI:
a) ((
(3)]
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.
24
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 8. 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. 2007. Bounding Methodology to Predict Full Scale Steam Dryer Loads from In-Plant Measurements, with the Inclusion of a Low Frequency Hydrodynamic Contribution (Rev. 0). C.D.I. Report No. 07-09 (C.D.I. Proprietary).
- 3. Continuum Dynamics, Inc. 2008. Flow-Induced Vibration in the Main Steam Lines at Browns Ferry Nuclear Units 1 and 2, With and Without Acoustic Side Branches, and Resulting Steam Dryer Loads (Rev. 0). C.D.I. Report No. 08-14 (C.D.I. Proprietary).
- 4. Browns Ferry Unit 1 Drawings. 2006. Files: 729E229-1.tif, 729E229-2.tif, and 729E229-3.tif. BFNl Email from G. Nelson dated 07 March 2006.
- 5. Structural Integrity Associates, Inc. 2007. Browns Ferry Unit 1 Main Steam Line 100%
CLTP Strain Data Transmission. SIA Letter Report No. KKF-07-012.
- 6. Communication from Enrico Betti. 2006. Excerpts from Entergy Calculation VYC-3001 (Rev. 3), EPU Steam Dryer Acceptance Criteria, Attachment I: VYNPS Steam Dryer Load Uncertainty (Proprietary).
- 7. NRC Request for Additional Information on the Hope Creek Generating Station, Extended Power Uprate. 2007. TAC No. MD3002. RAI No. 14.67.
- 8. NRC Request for Additional Information on the Browns Ferry Generating Station, Extended Power Uprate. 2009. RAI No. 204/168.
- 9. Structural Integrity Associates, Inc. 2007. Evaluation of Browns Ferry Unit 1 Strain Gage Uncertainty and Pressure Conversion Factors (Rev. 0). SIA Calculation Package No. BFN-12Q-302.
- 10. Continuum Dynamics, Inc. 2005. Vermont Yankee Instrument Position Uncertainty. Letter Report Dated 01 August 2005.
- 11. 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.
- 12. Continuum Dynamics, Inc. 2007. Finite Element Modeling Bias and Uncertainty Estimates Derived from the Hope Creek Unit 2 Dryer Shaker Test (Rev. 0). C.D.I. Report No. 07-27 (C.D.I. Proprietary).
25
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 13. NRC Request for Additional Information on the Hope Creek Generating Station, Extended Power Uprate. 2007. RAI No. 14.79.
- 14. NRC Request for Additional Information on the Hope Creek Generating Station, Extended Power Uprate. 2007. RAI No. 14.110.
26
ENCLOSURE 8 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT 1 TECHNICAL SPECIFICATIONS (TS) CHANGE TS-431 EXTENDED POWER UPRATE (EPU)
CDI TECHNICAL NOTE NO. 09-11NP, "LIMIT CURVE ANALYSIS WITH ACM REV. 4 FOR POWER ASCENSION TO 110% OLTP AT BROWNS FERRY NUCLEAR UNIT 1," REVISION 0 (NON-PROPRIETARY VERSION)
Attached is the non-proprietary version of CDI Technical Note No. 09-11 NP, "Limit Curve Analysis with ACM Rev. 4 for Power Ascension to 110% OLTP at Browns Ferry Nuclear Unit 1."
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information C.D.I. Technical Note No. 09-1 1NP Limit Curve Analysis with ACM Rev. 4 for Power Ascension to 110% OLTP at Browns Ferry Nuclear Unit 1 Revision 0 Prepared by Continuum Dynamics, Inc.
34 Lexington Avenue Ewing, NJ 08618 Prepared under Purchase Order No. 00077408 for TVA / Browns Ferry Nuclear Plant Nuclear Plant Road, P. 0. Box 2000 PAB-2M Decatur, AL 35609 Approved by (Va'14 15 Alan J. Bilanin Prepared by Milton E. Teske August 2009
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Table of Contents Section Page T able of C ontents.....................................................................
i
- 1. Introduction............................................................................
1
- 2. A pproach...............................................................................
2
- 3. L im it C urves...........................................................................
4
- 4. References...............................................
9
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 1. Introduction During power ascension of Browns Ferry Nuclear Unit 1 (BFN1), from Current Licensed Thermal Power (CLTP) to 110% Original Licensed Thermal Power (OLTP), TVA is required to monitor the dryer stresses at plant power levels that have not yet been achieved. Limit curves provide an upper bound safeguard against the potential for dryer stresses becoming higher than allowable, by estimating the not-to-be-exceeded main steam line pressure levels. In the case of BFN1, in-plant main steam line data have been analyzed at CLTP conditions (based on Unit 1 data) to provide steam dryer hydrodynamic loads [1]. CLTP is 105% of OLTP. A finite element model stress analysis has been undertaken on the CLTP loads [2]. These loads provide the basis for generation of the limit curves to be used during BFN1 power ascension.
Continuum Dynamics, Inc. (C.D.I.) has developed an acoustic circuit methodology (ACM) that determines the relationship between main steam line data and pressure on the steam dryer [3].
This methodology and the use of a finite element model analysis provide the computational algorithm from which dryer stresses at distinct steam dryer locations can be tracked through power ascension.
Limit curves allow TVA to limit dryer stress levels, by comparing the main steam line pressure readings - represented in Power Spectral Density (PSD) format - with the upper bound PSD derived from existing in-plant data.
This technical note summarizes the proposed approach that will be used to track the anticipated stress levels in the BFN1 steam dryer during power ascension to 110% OLTP, utilizing Rev. 4 of the ACM [4], and the options available to TVA should a limit curve be reached.
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 2. Approach The limit curve analysis for BFNl, to be used during power ascension, is patterned after the approach followed by Entergy Vermont Yankee (VY) in its power uprate [5]. In the VY analysis, two levels of steam dryer performance criteria were described: (1) a Level 1 pressure level based on maintaining the ASME allowable alternating stress value on the dryer, and (2) a Level 2 pressure level based on maintaining 80% of the allowable alternating stress value on the dryer. The VY approach is summarized in [6].
To develop the limit curves for BFNl, the stress levels in the dryer were calculated for the current plant acoustic signature, at CLTP conditions, and then used to determine how much the acoustic signature could be increased while maintaining stress levels below the stress fatigue limit. During power ascension, strain gage data will be converted to pressure in PSD format at each of the eight main steam line locations, for comparison with the limit curves. The strain gage data will be monitored throughout power ascension to observe the onset of discrete peaks, if they occur.
The finite element analysis of in-plant CLTP data found a lowest alternating stress ratio of 2.33 [2] as summarized in Table 1. The minimum stress ratios include the model bias and uncertainties for specific frequency ranges as suggested by the NRC [7, 8]. The results of the ACM Rev., 4 analysis (based on Quad Cities Unit 2, or QC2, in-plant data) are summarized in Table 2 (a negative bias is conservative). The standpipe excitation frequency of the main steam safety relief valves in BFN1 is anticipated to be 111 Hz [9], and thus the uncertainty determined around the QC2 excitation frequency of 155 Hz has been applied to the 109 to 113 Hz frequency interval. Note also that it is anticipated that the 218 Hz will be mitigated by plugging the blank standpipes prior to power ascension, and that the stress analysis is based on this modification.
The additional bias and uncertainties, as identified in [10], [11], [12], [13], [14], and [15], are shown in Table 3. SRSS of the uncertainties, added to the ACM bias, results in the total uncertainties shown in Table 4. These uncertainties were applied to the finite element analysis, resulting in the minimum stress ratio of 2.33.
Table 1. Peak Stress Limit Summary for ACM Rev. 4 Peak Stress Limit 13,600 psi (Level 1) 10,880 psi (Level 2)
Minimum Stress Ratio 2.33 1.86 2
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information Table 2. Bias and uncertainty for ACM Rev. 4
((
(3)))1 Table 3. BFN1 additional uncertainties (with references cited)
(3)))
Table 4. BFN 1 total uncertainty I((
(3)))1 3
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 3. Limit Curves Limit curves were generated from the in-plant CLTP strain gage data collected on Unit 1 and reported in [1]. These data were filtered across the frequency ranges shown in Table 5 to remove noise and extraneous signal content, as suggested in [16]. The resulting PSD curves for each of the eight strain gage locations were used to develop the limit curves, shown in Figures 1 to 4. Level 1 limit curves are found by multiplying the signals by the limiting stress ratio (2.33).
Level 2 limit curves are found by multiplying the signals by 80% of the limiting stress ratio (1.86). PSD results are then developed from the Level 1 and Level 2 pressure signals.
Consistent with the stress analysis [2], the peaks at 218 Hz on all eight strain gage signals were also filtered from the main steam line data prior to the development of the limit curves.
BFN1 intends to mitigate the effect of the eight blind standpipes on main steam lines A and D, prior to power ascension.
Table 5. Exclusion frequencies for BFN1 at CLTP conditions (VFD = variable frequency drive, Recirc = recirculation pumps)
Frequency Interval (Hz) Exclusion Cause 0.0-2.0 Mean 59.8 - 60.2 Line Noise 119.9 - 120.1 Line Noise 179.8 - 180.2 Line Noise 239.9 - 240.1 Line Noise 51.3-51.7 VFD (lx) 127.0 - 128.5 Recirc Pumps A, B Speed (5x) 217.9 - 219.6 Standpipe Excitation 4
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information (3)))1 Figure 1.
Level 1 (black) and Level 2 (red) limit curves for main steam line A, compared against the base curves (blue) over the frequency range of interest: A upper strain gage location (top); A lower strain gage location (bottom).
5
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information (3)))
Figure 2.
Level 1 (black) and Level 2 (red) limit curves for main steam line B, compared against the base curves (blue) over the frequency range of interest: B upper strain gage location (top); B lower strain gage location (bottom).
6
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information (3)
Figure 3.
Level 1 (black) and Level 2 (red) limit curves for main steam line C, compared against the base curves (blue) over the frequency range of interest: C upper strain gage location (top); C lower strain gage location (bottom).
7
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
((I (3)))
Figure 4.
Level 1 (black) and Level 2 (red) limit curves for main steam line D, compared against the base curves (blue) over the frequency range of interest: D upper strain gage location (top); D lower strain gage location (bottom).
8
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 4. References
- 1. Continuum Dynamics, Inc. 2009. Acoustic and Low Frequency Hydrodynamic Loads at CLTP Power Level to 110% OLTP Power Level on Browns Ferry Nuclear Unit 1 Steam Dryer to 250 Hz (Rev. 0). C.D.I. Report No. 09-22 (Proprietary).
- 2. Continuum Dynamics, Inc. 2009. Stress Assessment of Browns Ferry Nuclear Unit 1 Steam Dryer to 110% OLTP Power Level (Rev. 0). C.D.I. Report No. 09-24 (Proprietary).
- 3. 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 (Proprietary).
- 4. Continuum Dynamics, Inc. 2007. Methodology to Predict Full Scale Steam Dryer Loads from In-Plant Measurements, with the Inclusion of a Low Frequency Hydrodynamic Contribution (Rev. 1). C.D.I. Report No. 07-09 (Proprietary).
- 5. Entergy Nuclear Northeast. 2006. Entergy Vermont Yankee Steam Dryer Monitoring Plan (Rev. 4). Docket 50-271. No. BVY 06-056. Dated 29 June 2006.
- 6. State of Vermont Public Service Board. 2006. Petition of Vermont Department of Public Service for an Investigation into the Reliability of the Steam Dryer and Resulting Performance of the Vermont Yankee Nuclear Power Station under Uprate Conditions.
Docket No. 7195. Hearings held 17-18 August 2006.
- 7. NRC Request for Additional Information on the Hope Creek Generating Station, Extended Power Uprate. 2007. RAI No. 14.67.
- 8. NRC Request for Additional Information on the Browns Ferry Generating Station, Extended Power Uprate. 2009. RAI No. 204/168.
- 9. Continuum Dynamics, Inc. 2008. Flow-Induced Vibration in the Main Steam Lines at Browns Ferry Nuclear Units 1 and 2, With and Without Acoustic Side Branches, and Resulting Steam Dryer Loads (Rev. 0). C.D.I. Report No. 08-14 (Proprietary).
- 10. Structural Integrity Associates, Inc. 2007. Evaluation of Browns Ferry Unit 1 Strain Gage Uncertainty and Pressure Conversion Factors (Rev. 0). SIA Calculation Package No. BFN-12Q-302.
- 11. Continuum Dynamics, Inc. 2005. Vermont Yankee Instrument Position Uncertainty. Letter Report Dated 01 August 2005.
- 12. 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 (Rev. 0). Document No. AM-21005-008.
9
This Document Does Not Contain Continuum Dynamics, Inc. Proprietary Information
- 13. Continuum Dynamics, Inc. 2007. Finite Element Modeling Bias and Uncertainty Estimates Derived from the Hope Creek Unit 2 Dryer Shaker Test (Rev. 0). C.D.I. Report No. 07-27 (Proprietary).
- 14. NRC Request for Additional Information on the Hope Creek Generating Station, Extended Power Uprate. 2007. RAI No. 14.79.
- 15. NRC Request for Additional Information on the Hope Creek Generating Station, Extended Power Uprate. 2007. RAI No. 14.110.
- 16. Structural Integrity Associates, Inc. 2007. Browns Ferry Unit 1 Main Steam Line 100%
CLTP Strain Data Transmission. SIA Letter Report No. KKF-07-012.
10
ENCLOSURE 9 TENNESSEE VALLEY AUTHORITY BROWNS FERRY NUCLEAR PLANT (BFN)
UNIT I TECHNICAL SPECIFICATIONS (TS) CHANGE TS-431 EXTENDED POWER UPRATE (EPU)
CDI AFFIDAVIT Attached is the CDI affidavit for the proprietary information contained in Enclosures 1, 2, 3, and 4.
Coninum Dy n amic, inIn c.
(1609,) 538-0444 (609) 538-0464 fax
.34 Lexingtonl Avenue Ewing,'. NJ 08618-2302, AFFIDAVIT Re:
Technical Specificationis (TS) Changes TS-418 and TS-43 I -Extended Po~wer Uprate (EP~U) - Response toq Round 24, Requst~forAdd itiona1l Inmtlon (RýADI)
EMCB.208 Rgarding Stearn Dryer, Analyses; CD.I. Report No: 09-i22P "Acousitic and Low.FrequeincylIydropyrqami~c L,.Lads:"f" at CLTP 'Power Level..to> I 10% OLTEPoPWerLevel1 onrown's'ry: Nucledfr U-i "J Steam D~ryer to250 Hz;" Revision 0;:.
C.D.I. ReportNo.09-24P "Stres sAsse'sshmeiit, of Browis' F'err'y Nuclear,Unitý 1 Steaým Dryer to I 10%/&OLTP:,Power.ly Lx;Rev'ision
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C.D.L. Technical Note No. 09-1 IP 'Tin' 31bfveAnalysis with ACMARe. 4 fdr Power Ascensi~on to, 10 % OLTP at Browns Fefry ýNuclearUnitL 1 k ei.ision0
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1, Al an.ilai, b'~aiih oein
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Ihod, th~ position of Pres-ident:-An'd Seiioi sodiates,oftContinuium Dynaics, lfn(1ie~reiiiafterYreferred to a.CD.LC),,Ahd',Fýamniat'horized'to,miiake te withholding', from hPibi Recor 11h'hf6 finfrtion -contained inthe do t'
describedl in Paragraph 2. This Affida~vit. is 1§`ibmitte't t1he N&-
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- 3.
Thelriformatiofi sumzmarizes:
()apr69ess orrni'thod, incltiding supporting 'Adata idnl~
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of its use by.CD.1'~s.competitoi~swithout lcense'ý forfn CJ.lDI -con titute`Sa comnpetitive advantage overo'ther'c'ompa~nies;,
(b) Information which, if usdwould reduce his,expendtre.of.
resourceseor im rove S,.hiscompetiti*e position in the, design, manufacture;,
shipment, inst'allation, assurance of quality, or licensingofa im~ilar produt'~
-1c),Informaticin which ~discloses patentable subj ect m ali:fr,,
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~desiraible to obtain ptntpoein The infornmation-sought to be Withheld i's considered to be proprietary for: the reasons set forthin paragraphs 3(a), 3(b) ad
.3(c) above.
- 4.
The Information has, beený held in confidence by. C. D.I, its, owner.,The Info-.rmation has consistently been helda:inffcohfidence byC.D.I.. and no pu.blic, disclosureihas been made and it is not available to the puiblic. All disclosures, ý':to
- third parties,'which have been limited, have beenTmdepursuiiant to theferms and conditions contained in C.D.1 s:.Nondisclosure Sierec` Agreemnent which. must be fully execitedprior to Adisqlosure 5.:
The eInformiiati&o is a type,6i~tmriariy.'ield in confidence'by C.D.I;. and there is a::.
'rationalr basis. therefore. The'Informatioi'isa type-whieh;..DA.Iconsiders trade secret and is hecld in ccinfideiice by C.0 I because.it constitutes. a tioureof competitive, advantage.in the.comnpetition. and performance ~of such wcQrk i, Ite "industry. ;,Puiibcdiiclsure.*ef*the Ihfo(trtion "Iis likely to cause substatlarm
- t. o 4CD.I;+SLcOPtt'itivepsiion arid forecl6se or reduce the ayailabilif7 6fp~fit-*.
M ki'ng;1ppprtunti.
I declare under penalty, of perjury that -the foregoing-affidavit and the matters_;stated..
therein are true andbcorrect-lto beithe tesof my.koldef.
Executed on this.~
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Alan J BullnInff Continuum Dynamics, ~Inc.
Subscribed and sworn before me this day:
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urmeis ar Puli EILEEN P. BURMEISTER NOTARY PUBLIC OF NEWJERSEY My COMM. EXPIRESý MAY 21