ML043620059

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Cycle 12 End-of-Life Moderator Temperature Coefficient Limit Report
ML043620059
Person / Time
Site: South Texas STP Nuclear Operating Company icon.png
Issue date: 12/20/2004
From: Leazar D
South Texas
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
G25, NOC-AE-04001827, STI: 31817532
Download: ML043620059 (17)
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{{#Wiki_filter:Nuclear Operating Company South 7c Pro/cd Ekdrnc ancratia5Stition PO Bar 289 JSMdssorth, Teas 77483 V December 20, 2004 NOC-AE-04001827 I OCFR50.90 STI 31817532 File No. G25 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 South Texas Project Unit I Docket No. STN 50-498 Unit 1 Cycle 12 End of Life Moderator Temperature Coefficient Limit Report As a condition for approval of the conditional elimination of the most negative end of life moderator temperature coefficient measurement technical specification change as stated in the referenced correspondence, STP committed to submit the following information for the first three uses of this methodology at STP:

1. A summary of the plant data used to confirm that the Benchmark Criteria of Table 3-2 of WCAP-13749-P-A, Safety Evaluation Supporting the Conditional Elimination of the Most Negative EOL Moderator Temperature Coefficient Measurement, have been met; and,
2. The Most Negative EOL Moderator Temperature Coefficient Limit Report (as found in Appendix D of WCAP-13749-P-A).

The information is attached. This transmittal is the third and final submittal of the three required submittals. If there are any questions regarding this information, please contact Mr. Duane Gore at (361) 972-8909. D.A. Leazar

Manager, Nuclear Fuel and Analysis Attachments:
1. Plant Data Used to Confirm Benchmark Requirements
2. Most Negative End of Life Moderator Temperature Coefficient Limit Report for South Texas Unit 1, Cycle 12 40D

NOC-AE-04001827 Page 2 of 2 cc: (paper copy) (electronic copy) Bruce S. Mallett Regional Administrator, Region IV U. S. Nuclear Regulatory Commission 611 Ryan Plaza Drive, Suite 400 Arlington, Texas 76011-8064 U. S. Nuclear Regulatory Commission Attention: Document Control Desk One White Flint North 11555 Rockville Pike Rockville, MD 20852 Richard A. Ratliff Bureau of Radiation Control Texas Department of State Health Services 1100 West 49th Street Austin, TX 78756-3189 Jeffrey Cruz U. S. Nuclear Regulatory Commission P. 0. Box 289, Mail Code: MN1 16 Wadsworth, TX 77483 C. M. Canady City of Austin Electric Utility Department 721 Barton Springs Road Austin, TX 78704 A. H. Gutterman, Esquire Morgan, Lewis & Bockius LLP J. J. Nesrsta City Public Service David H. Jaffe U. S. Nuclear Regulatory Commission R.L.Balcom Texas Genco, LP C. A. Johnson AEP Texas Central Company Jon C. Wood Cox Smith Matthews C. Kirksey City of Austin R. K. Temple City Public Service Plant Data Used to Confirm Benchmark Requirements

Attachment I Page I of 6 Plant Data Used to Confirm Benchmark Requirements are Satisfied This attachment presents a comparison of the South Texas Unit 1 Cycle 12 core characteristics with the requirements for use of the Conditional Exemption of the Most Negative EOL Moderator Temperature Coefficient Measurement Methodology and presents plant data that support that the Benchmark Criteria presented in WCAP-13749-P-A are met. The Conditional Exemption of the Most Negative EOL Moderator Temperature Coefficient Measurement Methodology is described in WCAP-1 3749-P-A. This report was approved by the NRC with two requirements:

  • only PHOENIX/ANC calculation methods are used for the individual plant analyses relevant to determinations for the EOL MTC plant methodology, and
  • the predictive correction is reexamined if changes in core fuel designs or continued MTC calculation/measurement data show significant effect on the predictive correction.

The PHOENIX/ANC calculation methods were used for the South Texas Unit 1, Cycle 12, core design and relevant analyses. Also, the Unit 1, Cycle 12, core design does not represent a major change in core fuel design. Therefore, the Predictive Correction of-3 pcm/IF remains valid for this cycle. The Unit 1, Cycle 12, core meets both of the above requirements. A description of the data collection and calculations required to complete the Table 3 Worksheet of the Most Negative Moderator Temperature Coefficient Limit Report is presented in Attachment 2. Then the following data tables are provided in this attachment:

  • Table 1 - Benchmark Criteria for Application of the 300 ppm MTC Conditional Exemption Methodology (per WCAP-13749-P-A)
  • Table 2 - Flux Map Data: Assembly Powers and Core Tilt Criteria
  • Table 3 - Core Reactivity Balance Data
  • Table 4 - Low Power Physics Test Data (Beginning of Cycle, Hot Zero Power): Isothermal Temperature Coefficient (ITC)
  • Table 5 - Low Power Physics Test Data (Beginning of Cycle, Hot Zero Power): Individual Control Bank Worth Page 2 of 6 Table 1 Benchmark Criteria for Application of the 300 ppm MTC Conditional Exemption Methodology (per WCAP-13749-P-A)

Parameter Criteria Assembly Power (Measured Normal Reaction Rate) Measured Incore Quadrant Power Tilt (Low Power) Measured Incore Quadrant Power Tilt (Full Power) Core Reactivity (Cb) Difference BOL HZP ITC Individual Control Bank Worth Total Control Bank Worth +0.1 or 10% +4% +2% + 1000 pcm + 2 pcmI 0F +/-15 % or; 100 pcm +10%

Attachment I Page 3 of 6 Table 2 Page 1 of 2 Flux Map Data:Assembly Powers and Core Tilt Criteria Assembly Power Measured Incore Quadrant Power Tilt Benchmark Criteria Flux Map Number Measured to Predicted Error Criteria Requirement I Satisfied Benchmark Criteria Criteria Power Tilt Requirement I Satisfied _ 1 112001 % Diff 5.9 M-P -0.080 % Diff 4.7 112002 M-P -0.051 % Diff 5.2 112007 M-P -0.048 % Diff 5.3 112008 M-P -0.052 % Diff 5.2 112009 M-P -0.049 % Diff 5.0 112010 M-P -0.047 % Diff 4.5 112015 M-P -0.045 % Diff 4.1 112016 M-P -0.040 % Diff 4.0 112017 M-P -0.035 % Diff 3.9 112018 M-P -0.036 % Diff 4.0 112019A M-P -0.034 % Diff 3.9 112020 M-P -0.035 % Diff 4.2 112021 M-P -0.035 % Diff 4.4 112022 M-P -0.039 % Diff 4.5 112023 M-P -0.037 % Diff 4.7 112024 IM-P -0.044 % Diff within +/- 10% OR M-P within +/- 0.1 Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Max 1.00485 Min 0.99463 Max 1.00305 Min 0.99710 Max 1.00628 Min 0.99263 Max 1.00714 Min 0.99262 Max 1.00878 Min 0.98994 Max 1.00772 Min 0.99071 Max 1.00535 Min 0.99319 Max 1.00457 Min 0.99509 Max 1.00155 Min 0.99679 Max 1.00359 Min 0.99622 Max 1.00425 Min 0.99669 Max 1.00500 Min 0.99611 Max 1.00434 Min 0.99585 Max 1.00634 Min 0.99530 Max 1.00547 Min 0.99574 Max 1.00507 Min 0.99655 Max 1.00677 Min 0.99451 Maps at < 90% Reactor Power Max Power Tilt

  • 1.04 And Min Power Tilt 2 0.96 OR Maps at > 90%

Reactor Power Max Power Tilt < 1.02 And Min Power Tilt 2 0.98 Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes 112025 % Diff 5.8 M-P 0.042

Attachment I Page 4 of 6 Table 2 Page 2 of 2 Flux Map Data:Assembly Powers and Core Tilt Criteria Assembly Power Measured Incore Quadrant Power Tilt Benchmark Criteria Flux Map Number Measured to Predicted Error Criteria Satisfied Benchmark Criteria Criteria Power Tilt Requirement Satisfied Requirement .4- ______________ % Diff 6.7 112026 M-P 0.046 1 2 %Diff 6.5 112027 M-P 0.045 % Diff within +/- 10% OR M-P within +/-0.1 Yes Yes Max 1.00603 Min 0.99605 Max 1.00491 Min 0.99734 Max 1.00491 Min 0.99667 Yes Yes See Note I % Diff 6.8 Yes 112028 Yes M-P 0.047 Note 1: Maps at < 90% Reactor Power Max Power Tilt

  • 1.04 And Min Power Tilt 2 0.96 OR Maps at > 90% Reactor Power Max Power Tilt
  • 1.02 And Min Power Tilt 2 0.98

Attachment I Page 5 of 6 Table 3 Core Reactivity Balance Data Core Reactivity Difference (Critical boron) Reactivity Benchmark Criteria Surveillance Deviation Date/Time (pcm) Requirement Satisfied 8/15/03 12:38 116.7 Yes 8/26/03 14:45 57.5 Yes 9/23/03 15:43 -102.6 Yes 10/21/03 13:30 -197.1 Yes 11/18/03 14:52 -246.8 Yes 12/16/03 14:00 -322.1 Yes 1/13/04 15:12 -393.7 Yes 2/11/04 15:44 -337.5 Yes 3/3/04 14:48 -373.6 Reactivity Yes 4/2/04 9:09 -401.32 Deviation within Yes 5/5/04 15:34 -430.7 1000 pcm Yes 6/2/04 9:56 -381.7 Yes 6/29/04 16:30 -389.7 Yes 7/27/04 15:53 -379.1 Yes 8/25/04 10:14 -314.1 Yes 9/21/04 15:46 -189.7 Yes 10/19/04 14:40 -122.3 Yes 11/16/04 14:28 -25.42 Yes

Attachment I Page 6 of 6 Table 4 Low Power Physics Test Data (Beginning of Cycle, Hot Zero Power): Isothermal Temperature Coefficient (ITC)

  • Note: I pcm = I x 105 AK/K Table 5 Low Power Physics Test Data (Beginning of Cycle, Hot Zero Power):

Individual Control Bank Worth Benchmark Criteria Measured Predicted A Error Bank (pcm)* (pcm)* (pcm)* % Error Requirement Satisfied Shutdown Bank A 307.1 288.5 18.6 6.4 Yes Shutdown Bank B 898.8 912.6 -13.8 -1.5 % Error Yes Shutdown Bank C 457.1 442.0 15.1 3.4 within +15% Yes Shutdown Bank D 465.3 441.1 24.2 5.5 Yes Shutdown Bank E 448.1 469.2 -21.1 -4.5 OR Yes Control Bank A 646.9 676.2 -29.3 -4.3 Yes Control Bank B 788.9 749.1 39.8 5.3 A Error Yes Control Bank C 700.6 710.9 -10.3 -1.5 within d100 pcm Yes Control Bank D 558.9 541.9 17 3.1 Yes Total Control 5271.7 5231.5 40.2 0.77 % Error Yes Bank Worth within+10%

  • Note: I pcm = 1 x 10- AK/K Most Negative End of Life Moderator Temperature Coefficient Limit Report for South Texas Unit 1, Cycle 12

Page 1 of 7 Most Negative End of Life Moderator Temperature Coefficient Limit Report for South Texas Unit 1, Cycle 12 (Measured 300 ppm Burnup, as per WCAP-13749-P-A, Appendix D) PURPOSE: The purpose of this document is to present cycle-specific best estimate data for use in confirming the most negative end of life moderator temperature coefficient (MTC) limit in Technical Specification 3.1.1.3. This document also summarizes the methodology used for determining if a HFP 300 ppm MTC measurement is required. PRECAUTIONS AND LIMITATIONS: The EOL MTC elimination data presented in this document apply to South Texas Unit I Cycle 12 only and may not be used for other operating cycles. The following reference is applicable to this document: Fetterman, R. J., Slagle, W. H., Safety Evaluation Supporting the Conditional Exemption of the Most Negative EOL Moderator Temperature Coefficient Measurement, WCAP-1 3749-P-A, March, 1997. PROCEDURE: All core performance benchmark criteria listed in Table 1 must be met for the current operating cycle. These criteria are confirmed from startup physics test results and routine HFP boron concentration and flux map surveillance performed during the cycle. If all core performance benchmark criteria are met, then the Revised Predicted MTC may be calculated per the algorithm given in Table 2. The required cycle specific data are provided in Table 2 and Figure 1. This methodology is also described in the above Reference. If all core performance benchmark criteria are met, and the Revised Predicted MTC is less negative than the 300 ppm limit specified in COLR Section 2.4.3, then a measurement is not required. Note that Figure 1 is not entirely linear. However, the deviation is slight enough that linear interpolation between adjacent points from the data at the bottom of the Figure is acceptable. Page 2 of 7 Table 1 Benchmark Criteria for Application of the 300 ppm MTC Conditional Exemption Methodology Parameter Criteria Assembly Power (Measured Normal Reaction Rate) Measured Incore Quadrant Power Tilt (Low Power) Measured Incore Quadrant Power Tilt (Full Power) Core Reactivity (Cb) Difference BOL HZP ITC Individual Control Bank Worth Total Control Bank Worth O0.1 or 10% +/-2% +/- 1000 pcm + 2 pcm/IF +/- 15 % or i 100 POcm +/- 10% Page 3 of 7 Table 2 Algorithm for Determining the Revised Predicted Ncar-EOL 300 ppm MTC The Revised Predicted MTC = Predicted MTC + AFD Correction - 3 pcm/IF where: Predicted MTC is calculated from Figure 1 at the burnup corresponding to the measurement of 300 ppm at RTP conditions, AFD Correction is the more negative value of: { 0 pcm/IF, ( AAFD

  • AFD Sensitivity) }

AAFD is the measured AFD minus the predicted AFD from an incore flux map taken at or near the bumup corresponding to 300 ppm. AFD Sensitivity = 0.05 pcm / 'F / AAFD Predictive Correction is -3 pcm/IF, as included in the equation for the Revised Predicted MTC. Page 4 of 7 Table 3 Worksheet for Calculating the Predicted Near-EOL 300 ppm MTC Unit: 1, Cycle 12 Date: 11/22/2004 Time: 1012 Reference for Cycle-Specific MTC Data: A41009-00548UB Rev.A, The Nuclear Design and Core Management of the South Texas Unit 1 Nuclear Power Plant Cycle 12 Redesign. Part A. Predicted MTC A.1 Cycle Average Burnup Corresponding to the HFP ARO equilibrium xenon CB of 300 ppm. 17452.8 MWD/MTU A.2 Predicted HFP ARO MTC corresponding to burnup (A.1) -35.24 pcm/IF Part B. AFD Correction B.1 Burnup of most recent HFP, equilibrium conditions incore flux map 17238.0 MWID/MTU B.2 Measured HFP AFD at burnup (B.1) Reference incore flux map: ID: 112028 Date: 11/16/04 -2.06 % AFD B.3 Predicted HFP AFD at burnup (B. 1) -2.54 % AFD B.4 MTC Sensitivity to AFD 0.05 pcm/IF/AAFD B.5 AFD Correction, more negative of { 0 pcm/IF, B.4 *(B.2 - B.3)} 0 pcm/IF Part C. Revised Prediction C.1 Revised Prediction (A.2 + B.5 - 3) -38.24 pcm/°F C.2 Surveillance Limit (COLR 2.3.3) -53.72 pcml°F If C.1 is less negative than C.2, then the HFP 300 ppm MTC measurement is not required per Specification 4.1.1.3. Page 5 of 7 Figurc 1 Predicted HFP FOP 300 ppm MTC vs. Cycle 12 Redesign Burnup -33. I1T1 T I I I I I I I I I 11 IT xrrll I l X1r I I 1 TC1H1 zQ,. 0 UH p. v PS a to 0U 0I-. 4. I d_ -3 -i - -34. -I I Ix I I I _1* I I I I I_ I I I I I I I I ______________I I _ _1 I I I I I _I -_____ s __ __ __ __ __ _I I I I I I I I I I _~ I I , _ __ _ _____ ___ X_- __ _ _I I I I I -35. N -35.. _ _ _ _ _ _ _ _ -36.1E ~ E L E F EI _ S.,_ -36.0 I .....I..- 14000 15000 16000 17000 18000 19000 CYCLE BURNUP (WAD/MTU) Cycle Burnup (MWD/MTU) Moderator Temperature Coefficients (pcm/ 0F) 14000 16000 17000 19000 -33.65 -34.60 -35.05 -35.91 Page 6 of 7 Table 4 Data Collection and Calculations Required to Complete the Table 3 Worksheet of the Most Negative Moderator Temperature Coefficient Limit Report Data at the 300 ppm Boron Point

  • RCS Boron at 300 ppm at 02:35 on 11/22/04.

. Bumup at 300 ppm: 17452.8 MWD/MTU (A.1)

  • Predicted MTC: -35.24 pcmI0F (A.2)

Data from Last Flux Map:

  • Flux Map Number: 112028 (B.2)
  • Reactor Power 100% RTP Note: The monthlyflux map was performed about a week before the unit reached the 300 ppm concentration value. Data from this flux map was usedfor the AFD Correction.
  • Burnup 17238.0 MWD/MTU (11.1)
  • Measured Axial Offset (MAO): -2.06% (B.2)

Note: The Westinghouse BEACON computer code (similar to the Westinghouse INCORE code) determines Axial Offset (AO), not Axial Flux Difference (AFD). Therefore, the AO must be converted to AFD before use. The relationship betveen AO andAFD is AFD = Axial Offset

  • Fractional Power
  • Axial Flux Difference Lower Predicted AO (LPAO):

-2.35% at 16000 MWD/MTU Higher Predicted AO (HPAO): -2.73% at 18500 MWD/MTU Predicted AO (PAO) = PAO = BueAfea$edA -B I U@~LoerprediccedAO X (HPA O-LPAO )+ LPA O B/ U~figherPredkctedAO _B/U@LowerPrerdiciedAO PAO = (17238.0 - 16000)/(18500 - 16000) * (-2.73% + 2.35%) - 2.35% = -2.54% (B.3) A AFD = (MAO-PAO) * (Reactor Power (%) / 100%) = (-2.06% + 2.54%) * (100% / 100%) = 0.48%

Page 7 of 7 Table 4 (cont.) Data Collection and Calculations Required to Complete the Table 3 Worksheet of the Most Negative Moderator Temperature Coefficient Limit Report Determination of the Revised Predicted Moderator Temperature Coefficient (MTC) AFD Sensitivity: 0.05 pcm/IF/ AAFD AFD Correction: 0 pcm/IF (B.5) where: AFD Correction is the more negative of the following: 0 pcm/IF or (AAFD

  • AFD Sensitivity) 0 pcm/IF or (0.48
  • 0.05 pcm/0F/ AAFD) 0 pcm/nF or 0.024 pcm/IF

.0 pcm/IF Revised Predicted MTC = Predicted MTC + AFD Correction - 3 pcm/IF = -35.24 pcm/IF + 0.0 pcm/IF - 3 pcrn/mF = -38.24 pcm/IF (C.1)}}

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