NOC-AE-04001827, Cycle 12 End-of-Life Moderator Temperature Coefficient Limit Report

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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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Text

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

Attachment 1 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

Attachment 1 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) +0.1 or 10%

Measured Incore Quadrant Power Tilt (Low Power) +4%

Measured Incore Quadrant Power Tilt (Full Power) +2%

Core Reactivity (Cb) Difference + 1000 pcm BOL HZP ITC + 2 pcmI 0F Individual Control Bank Worth +/-15 % or; 100 pcm Total Control Bank Worth +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 Benchmark Criteria Flux Map Measured to Predicted Criteria Criteria Number 1_

Error Requirement I Satisfied Power Tilt Requirement I Satisfied

% Diff 5.9 Max 1.00485 112001 Yes Yes M-P -0.080 Min 0.99463

% Diff 4.7 Max 1.00305 112002 Yes Yes M-P -0.051 Min 0.99710

% Diff 5.2 Max 1.00628 112007 Yes Yes M-P -0.048 Min 0.99263

% Diff 5.3 Max 1.00714 112008 Yes Yes M-P -0.052 Min 0.99262

% Diff 5.2 Max 1.00878 112009 Yes Yes M-P -0.049 Min 0.98994 Maps at < 90%

% Diff 5.0 Max 1.00772 Reactor Power 112010 Yes Yes M-P -0.047 Min 0.99071 Max Power

% Diff 4.5 Max 1.00535 Tilt

  • 1.04 112015 Yes And Yes M-P -0.045 Min 0.99319 Min Power

% Diff 4.1  % Diff within Max 1.00457 Tilt 2 0.96 112016 Yes Yes M-P -0.040 +/- 10% Min 0.99509

% Diff 4.0 Max 1.00155 112017 OR Yes OR Yes M-P -0.035 Min 0.99679

% Diff 3.9 M-P within Max 1.00359 112018 Yes Yes M-P -0.036 +/- 0.1 Min 0.99622 Maps at > 90%

Reactor Power

% Diff 4.0 Max 1.00425 Max Power 112019A Yes Yes M-P -0.034 Min 0.99669 Tilt < 1.02

% Diff 3.9 Max 1.00500 And 112020 Yes Min Power Yes M-P -0.035 Min 0.99611 Tilt 2 0.98

% Diff 4.2 Max 1.00434 112021 Yes Yes M-P -0.035 Min 0.99585

% Diff 4.4 Max 1.00634 112022 Yes Yes M-P -0.039 Min 0.99530

% Diff 4.5 Max 1.00547 112023 Yes Yes M-P -0.037 Min 0.99574

% Diff 4.7 Max 1.00507 112024 Yes Yes IM-P -0.044 Min 0.99655

% Diff 5.8 Max 1.00677 112025 Yes Yes M-P 0.042 Min 0.99451

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 Benchmark Criteria Flux Map Measured to Predicted Criteria Criteria Number .4-Error Requirement Satisfied Power Tilt Requirement Satisfied

% Diff 6.7  % Diff within Max 1.00603 112026 Yes Yes M-P 0.046 +/- 10% Min 0.99605 1%Diff 2 6.5 Max 1.00491 See Note I 112027 OR Yes Yes M-P 0.045 Min 0.99734

% Diff 6.8 M-P within Max 1.00491 112028 Yes Yes M-P 0.047 +/-0.1 Min 0.99667 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

Attachment 2 Most Negative End of Life Moderator Temperature Coefficient Limit Report for South Texas Unit 1, Cycle 12

Attachment 2 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 Supportingthe ConditionalExemption 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.

Attachment 2 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) O0.1 or 10%

Measured Incore Quadrant Power Tilt (Low Power)

Measured Incore Quadrant Power Tilt (Full Power) +/-2%

Core Reactivity (Cb) Difference +/- 1000 pcm BOL HZP ITC + 2 pcm/IF Individual Control Bank Worth +/- 15 % or i 100 POcm Total Control Bank Worth +/- 10%

Attachment 2 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.

Attachment 2 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.

Attachment 2 Page 5 of 7 Figurc 1 Predicted HFP FOP 300 ppm MTC vs. Cycle 12 Redesign Burnup

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p.

v I I_ II I______________I I III I 0 -34.

U PS a _ _ _1I _II -_____ II II

_ __ ___ s __ __ __ __ __ _I to I I I I II I I _~I I I I

-35. , ___ _ _____ ___ X_- __ _ _I 0

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I I _% _. I

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-35.. _ _ _ _ _ _ _ _ ._ ._ . _ . _ . . .

-36.1E

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-36 .0 ... ..I..- I 14000 15000 16000 17000 18000 19000 CYCLE BURNUP (WAD/MTU)

Cycle Burnup Moderator Temperature Coefficients (MWD/MTU) (pcm/ 0F) 14000 -33.65 16000 -34.60 17000 -35.05 19000 -35.91

Attachment 2 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 pcmI0 F (A.2)

Data from Last Flux Map:

  • Flux Map Number: 112028 (B.2)
  • Reactor Power 100% RTP Note: The monthlyflux map was performedabout a week before the unit reachedthe 300 ppm concentration value. Datafrom thisflux 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) determinesAxial Offset (AO), not Axial Flux Difference (AFD). Therefore, the AO must be converted to AFD before use. The relationshipbetveen 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%

Attachment 2 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/0 F/ 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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