ML18177A252
| ML18177A252 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 06/22/2018 |
| From: | Sharp S Northern States Power Company, Minnesota, Xcel Energy |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| L-Pl-18-035 | |
| Download: ML18177A252 (15) | |
Text
1717 Wakonade Drive Welch, MN 55089 Xcel Energy RESPONSIBLE BY NATURE 800. 895 .4999 xcelenergy.com JUN 2 2 2018 L-Pl-18-035 10 CFR 50.46 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Prairie Island Nuclear Generating Plant, Units 1 and 2 Docket Nos. 50-282 and 50-306 Renewed Facility Operating License Nos. DPR-42 and DPR-60 2017 10 CFR 50 .46 LOCA Annual Report Pursuant to 10 CFR 50.46(a)(3)(ii), Northern States Power Company, a Minnesota corporation, doing business as Xcel Energy (hereafter "NSPM"), submits the 2017 annual report of changes and errors associated with the Prairie Island Nuclear Generating Plant (PINGP) Units 1 and 2 Emergency Core Cooling System (ECCS) analyses (Enclosure 1).
The peak cladding temperature (PCT) for PINGP Unit 1 and Unit 2 were unchanged since the last annual report for the LOCA analyses. The plant specific changes and errors (absolute value) since the last annual report are summarized below:
LBLOCA Unit 1 None SBLOCA Unit 1 None LBLOCA Unit 2 None SBLOCA Unit 2 None There were no changes that resulted in more than a O degrees Fahrenheit PCT penalty. contains the 10 CFR 50.46 PCT Rack-up sheets addressed in the report.
If there is any question or if any additional information is needed, please contact Frank Sienczak, at 612-342-8987.
Document Control Desk Page 2 Summary of Commitments
, T b ~ n e w commitments and no revisions to existing commitments.
Scott Sharp Site Vice President, Prairie Island Nuclear Generating Plant Northern States Power Company - Minnesota Enclosure (1) cc: Regional Administrator, Region Ill, USNRC Project Manager, Prairie Island Nuclear Generating Plant, USNRC Resident Inspector, Prairie Island Nuclear Generating Plant, USNRC
Document Control Desk Page 3 ENCLOSURE 1 WESTINGHOUSE LETTER LTR-LIS-18-27 12 Pages Follow
Westinghouse Non-Proprietaty Class 3
@Westinghouse Westinghouse Electric Company 1000 Westinghouse Drive Cranben-y Township, Pennsylvania 16066 USA Direct tel: (412) 374-5598 e-mail: mcmillh@westinghouse.com Our ref; LTR-LIS-18-27 February 22, 2018 Prairie Island Units 1 and 2 10 CFR 50.46 Annual Notification and Reporting for 2017
Dear Sir or Madam:
This is a notification of 10 CFR 50.46 reporting information pertaining to the Westinghouse Electric Company Evaluation Models/analyses. As committed to in WCAP-13451, Westinghouse Methodology for Implementation of 10 CFR 50.46 Rep01iing, Westinghouse is providing an Annual Report for Emergency Core Cooling System (ECCS)
Evaluation Model changes and errors for the 2017 model year. All necessary standardized reporting pages for any changes and errors for the Evaluation Models utilized for your plant(s) are enclosed, consistent with the commitment following the NUPIC audit in early 1999. Peak Clad Temperature (PCT) summary sheets are enclosed. All necessary revisions for any non-zero, non-discretionary PCT changes have been included. Changes with estimated PCT impacts of 0°F may not be presented on the PCT summmy sheet. The Evaluation Model changes and errors (except any plant-specific errors in the application of the model) will be provided to the NRC via Westinghouse letter.
This information is for your use in making a determination relative to the reporting requirements of 10 CFR 50.46.
The information that is provided in this letter was prepared in accordance with Westinghouse's Quality Management System (QMS). Please contact your LOCA plant cognizant engineer (PCE), Danial Utley (412-374-6663), if there are any questions concerning this information.
Author: (Electronically Approved)* Verified: (Electronically Approved)*
Heather McMillen Danial W. Utley LOCA Integrated Services II LOCA Integrated Services II Approved: (Electronically Approved)*
Jason R. Beebe Manager, LOCA Integrated Se1vices II
Attachment:
10 CFR 50.46 Reporting Text and PCT Summary Sheets (10 Pages)
- Electronically approved records are authenticated in the electronic document management system.
© 2018 Westinghouse Electric Company LLC All Rights Resen*ecl Page 4 of 15
- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)
Attachment to L TR-LIS-18-27 February 22, 2018 Page 1 of 10 GENERAL CODE MAINTENANCE
Background
Various changes have been made to enhance the usability of codes and to streamline future analyses.
Examples of these changes include modifying input variable definitions, units and defaults; improving the input diagnostic checks; enhancing the code output; optimizing active coding; and eliminating inactive coding. These changes represent Discretionary Changes that will be implemented on a forward-fit basis in accordance with Section 4.1.1 of WCAP-13451.
Affected Evaluation Model(s) 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM 1981 Westinghouse Large Break LOCA Evaluation Model with BASH 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP Estimated Effect The nature of these changes leads to an estimated Peak Cladding Temperature (PCT) impact of0°F.
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- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)
Attachment to LTR-LIS-18-27 February 22, 2018 Page 2 of 10 ERROR IN THE UPPER PLENUM FLUID VOLUME CALCULATION
Background
An error was found in the fluid volume calculation in the upper plenum where the support column outer diameter was being used instead of the inner diameter. The correction of this error lead to a reduction in the upper plenum fluid volume used in the Appendix K Large Break LOCA and Small Break LOCA analyses. The corrected values represent a less than 1% change in the total RCS fluid volume and will be incorporated on a forward-fit basis, based on the evaluated impact on the current licensing basis analysis results. These changes represent a Non-Discretionaty Change in accordance with Section 4.1.2 of WCAP-13451.
Affected Evaluation Model(s) 1981 Westinghouse Large Break LOCA Evaluation Model with BASH 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP Estimated Effect The differences in the upper plenum fluid volume are relatively minor and have been evaluated to have a negligible effect on large and small break LOCA analysis results, leading to an estimated PCT impact of 0°F.
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- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was a9ded by the PRIME system upon its validation)
Attachment to LTR-LIS-18-27 February 22, 2018 Page 3 of 10 INCONSISTENT APPLICATION OF NUMERICAL RAMP APPLIED TO THE ENTRAINED LIQUID/ VAPOR INTERFACIAL DRAG COEFFICIENT
Background
A numerical ramp which was used to account for the disappearance of the entrained liquid phase was applied to the entrained liquid / vapor interfacial drag coefficient. The numerical ramp was applied such that the interfacial drag coefficient used in the solution of the entrained liquid and vapor momentum equations was not consistent. WCOBRA/TRAC was updated to apply the numerical ramp prior to usage of the interfacial drag coefficient in the momentum equations, such that a consistent interfacial drag coefficient was used in the entrained liquid and vapor momentum equations.
This item represents a Non-Discretionary Change in accordance with Section 4.1.2 of WCAP-13451.
Affected Evaluation Model(s) 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect Based on the code validation results, the impact of correcting the error is estimated to have a 0°F impact on PCT.
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- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)
Attachment to LTR-LIS-18-27 Februaiy 22, 2018 Page 4 of 10 INAPPROPRIATE RESETTING OF TRANSVERSE LIQUID MASS FLOW
Background
In the WCOBRA/TRAC routine which evaluates the mass and energy residual error of the time step solution, the transverse liquid mass flow is reset as the liquid phase disappears. The routine is updated to remove the resetting of the transverse liquid mass flow since the routine is to only evaluate the residual error based on the time step solution values.
This item represents a Non-Discretionaiy Change in accordance with Section 4.1.2 of WCAP-13451.
Affected Evaluation Model(s) 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect Based on the code validation results and limited applicability of the logic removed, correcting the error is estimated to have a 0°F impact on PCT.
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- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)
Attachment to LTR-LIS-18-27 February 22, 2018 Page 5 of 10 STEADY-STATE FUEL TEMPERATURE CALIBRATION METHOD
Background
In the Automated Statistical Treatment of Uncetiainty Method (ASTRUM) Best-Estimate (BE) Large-Break Loss-of-Coolant Accident (LBLOCA) Evaluation Model (EM), the steady-state fuel pellet temperature calibration method involves solving for the hot gap width (AGF ACT) to calibrate the fuel temperature for each fuel rod. In some infrequent situations, small non-conservatisms can occur in the calibration process such that the resulting fuel pellet temperature will be slightly lower than intended and outside the acceptable range defined by Table 12-6 ofWCAP-16009-P/NP-A [1].
This issue has been evaluated to estimate the impact on ASTRUM BE LBLOCA analysis results.
The resolution of this issue represents a Non-Discretionary Change in accordance with Section 4.1.2 of WCAP-13451.
Affected Evaluation Model(s) 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect A review of licensing basis analyses concluded that the potential non-conservatisms in the fuel pellet temperature calibration did not occur for the limiting analysis cases. Therefore, an estimated PCT impact of0°F is assigned for 10 CFR 50.46 repotiing purposes.
Reference(s)
- 1) WCAP-16009-P/NP-A, "Realistic Large-Break LOCA Evaluation Methodology Using the Automated Statistical Treatment Of Uncertainty Method (ASTRUM)," January 2005.
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- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)
Attachment to LTR-LIS-18-27 February 22, 2018 Page 6 of 10 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Prairie Island Unit 1 Utility Name: Xcel Energy, Inc Revision Date: 2/1/2018 Analysis Information EM: ASTRUM (2004) Analysis Date: 11/30/2007 Limiting Break Size: Split FQ: 2.5 FdH: 1.77 Fuel: 422 Vantage+ SGTP (%): 10 Notes:
Clad Temp (°F) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1765 PCT ASSESSMENTS (Delta PCT)
A. PRIOR ECCS MODEL ASSESSMENTS
. Evaluation of Fuel Pellet Thermal Conductivity Degradation and Peaking 227 2 (a)
Factor Burndown 2 . Revised Heat Transfer Multiplier Distributions -2 3 3 . Error in Burst Strain Application 25 4 B. PLANNED PLANT MODIFICATION EVALUATIONS 1 . None 0 C. 2017 ECCS MODEL ASSESSMENTS 1 . None 0 D.OTHER*
1 . None 0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT=. 2015
- It is recommended that the licensee determine if these PCT allocations should be considered with respect to 10 CFR 50.46 reporting requirements.
- References 1 . WCAP-17783-P, "Best-Estimate Analysis of the Large-Break Loss-of-Coolant Accident for Prairie Island Units 1 and 2 with Replacement Steam Generators Using ASTRUM Methodology," June 2013.
2 . LTR-LIS-12-414, "Prairie Island Units I and 2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown," September 20, 2012.
3 . LTR-LIS-13-366, Revision !, "Prairie Island Units 1 and 2 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," August 2013.
4 . LTR-LIS-14-50, "Prairie Island Units 1 and 2 10 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.
Notes:
(a) This evaluation credits peaking factor burndown, see Reference 2.
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- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)
Attachment to LTR-LIS-18-27 February 22, 2018 Page 7 of 10 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Prairie Island Unit 1 Utility Name: Xcel Energy, Inc Revision Date: 2/1/2018 Analysis Information EM: NOTRUMP Analysis Date: 1/21/2008 Limiting Break Size: 3 inch FQ: 2.5 FdH: 1.77 Fuel: 422 Vantage+ SGTP (%): 10 Notes: Zirlo (14Xl4), Framatome RSG Clad Temp (°F) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 959 PCT ASSESSMENTS (Delta PCT)
A. PRIOR ECCS MODEL ASSESSMENTS I . None 0 B. PLANNED PLANT MODIFICATION EVALUATIO NS I . None 0 C. 2017 ECCS MODEL ASSESSMENTS I . None 0 D.OTHER*
I . None 0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT= 959
- It is recommended that the licensee determine if these PCT allocations should be considered with respect to 10 CFR 50.46 reporting requirements.
References I . LTR-LIS-08-158, "Transmittal of Future Prairie Island Units I and 2 PCT Summaries," February 2008.
Notes:
None Page 11 of 15
- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)
Attachment to LTR-LIS-18-27 February 22, 2018 Page 8 of 10 Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Prairie Island Unit 2 Utility Name: Xcel Energy, Inc Revision Date: 2/1/2018 Analysis Information EM: ASTRUM (2004) Analysis Date: 11/30/2007 Limiting Break Size: Split FQ: 2.5 FdH: 1.77 Fuel: 422 Vantage+ SGTP (%): 10 Notes:
Clad Temp (°F) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1765 PCT ASSESSMENTS (Delta PCT)
A. PRIOR ECCS MODEL ASSESSMENTS
. Evaluation of Fuel Pellet Thermal Conductivity Degradation and Peaking 227 2 (a), (b)
Factor Burndown 2 . Revised Heat Transfer Multiplier Distributions -2 3 3 . Error in Burst Strain Application 25 4 B. PLANNED PLANT MODIFICATION EVALUATIONS I . None 0 C. 2017 ECCS MODEL ASSESSMENTS I . None 0 D.OTHER*
I . None 0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT= 2015
- It is recommended that the licensee determine if these PCT allocations should be considered with respect to IO CFR 50.46 reporting requirements.
References I . WCAP-17783-P, "Best-Estimate Analysis of the Large-Break Loss-of-Coolant Accident for Prairie Island Units I and 2 with Replacement Steam Generators Using ASTRUM Methodology," June 2013.
2 . LTR-LIS-12-414, "Prairie Island Units 1 and 2, 10 CFR 50.46 Notification and Reporting for Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown," September 20, 2012.
3 . LTR-LIS-13-366, Revision 1, "Prairie Island Units 1 and 2 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions," August 2013.
4 . LTR-LIS-14-50, "Prairie Island Units 1 and 2 10 CFR 50.46 Report for the HOTSPOT Burst Strain Error Correction," January 2014.
Notes:
(a) This evaluation credits peaking factor burndown, see Reference 2.
(b) The reporting text and line item originally identified for Unit I in Reference 2 is applicable to Unit 2 with RSGs.
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- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)
Attachment to LTR-LIS-18-27 February 22, 2018 Page 9 of 10 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Prairie Island Unit 2 Utility Name: Xcel Energy, Inc Revision Date: 2/1/2018 Analysis Information EM: NOTRUMP Analysis Date: 1/21/2008 Limiting llreak Size: 3 inch FQ: 2.5 FdH: 1.77 Fuel: 422 Vantage+ SGTP (%): 10 Notes: Zirlo (14Xl4), AREVA RSG Clad Temp (°F) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 959 1, 2 a PCT ASSESSMENTS (Delta PCT)
A. PRIOR ECCS MODEL ASSESSMENTS 1 . None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS l . None 0 C. 2017 ECCS MODEL ASSESSMENTS l . None 0 D. OTHER*
l . None 0 LICENSING BASIS PCT+ PCT ASSESSMENTS PCT= 959
- It is recommended that the licensee determine if these PCT allocations should be considered with respect to 10 CFR 50.46 reporting requirements.
References 1 . LTR-LIS-08-158, "Transmittal of Future Prairie Island Units 1 and 2 PCT Summaries," February 2008.
2 . LTR-LIS-13-274, "Prairie Island Units I and 2, 10 CFR 50.46 Summary Sheets for the Evaluation to Support the Unit 2 Installation of AREVA Model 56/19 Replacement Steam Generators (RSGs)," June 2013.
Notes:
(a) The Unit I AOR is applicable to Unit 2 with the RSGs installed.
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Attachment to LTR-LIS-18-27 Februaiy 22, 2018 Page 10 of 10 10 CFR 50.46 Reporting SharePoint Site Check:
EMs applicable to Prairie Island:
Realistic Large Break - ASTRUM (2004)
Appendix K Small Break - NOTRUMP 2017 Issues Transmittal Letter Issue Descri tion None None Page 14 of 15
- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)
L TR-LIS-18-27 Revision 0 Proprietary Class 2
- This page was added to the quality record by the PRIME system upon its validation and shall not be considered in the page numbering of this document.**
Approval Information Author Approval McMillen Heather Feb-22-2018 08:36:28 Verifier Approval Utley Danial Feb-23-2018 09:18:56 Manager Approval Beebe Jason R Feb-26-2018 11 :39:33 Files approved on Feb-26-2018 Page 15 of 15
- This record was final approved on 2/26/2018 11 :39:33 AM. ( This statement was added by the PRIME system upon its validation)