L-PI-17-030, Transmittal of 2016 10CFR 50.46 LOCA Annual Report

Transmittal of 2016 10CFR 50.46 LOCA Annual Report

ML17179A798
Person / Time
Site:	Prairie Island
Issue date:	06/28/2017
From:	Northard S Northern States Power Co, Xcel Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
L-PI-17-030
Download: ML17179A798 (13)

Text

Xce/ Energy@ Prairie Island Nuclear Generating Plant 1717 Wakonade Drive East Welch. MN 55089 JUN 2 B 2017 L-PI-17-030 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 2016 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 2016 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 0 degrees Fahrenheit PCT penalty. contains the 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 651-267-1740.

Xcel Energy@ Prairie Island Nuclear Generating Plant 1717 Wakonade Drive East Welch. MN 55089 Summary of Commitments

~~;;) new commitments and no changes to existing commitments.

Scott Northard Site Vice President, Prairie Island Nuclear Generating Plant Northern States Power Company- Minnesota Enclosure cc: Regional Administrator, Region Ill, USNRC Project Manager, Prairie Island Nuclear Generating Plant, USNRC Resident Inspector, Prairie Island Nuclear Generatin9 Plant, USNRC

Document Control Desk Page 2 ENCLOSURE 1 WESTINGHOUSE LETTER LTR-LIS-17-45 (Reference 1 of this letter) 10 Pages Follow

Westinghouse Non-Proprietary Class 3

@Westinghouse Westinghouse Electric Company Engineering Center ofExceUence 1000 Westinghouse Drive Cranberry Township, Pennsylvania 16066 USA Directtel: (412) 374-5598 e-mail: mcrnillh@westinghouse.com Ounef: LTR-LIS-17-45 February 8, 2017 Prairie Island Units 1 and 2 10 CFR 50.46 Annual Notification and Reporting for 2016

Dear Sir or Madam:

This is a notification of 10 CFR 50.46 rep01ting 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 Reporting, Westinghouse is providing an Annual Report for Emergency Core Cooling System (ECCS)

Evaluation Model changes and errors for the 2016 model year. All necessaty standardized* reporting pages for any changes and enors for the Evaluation Models utilized for your plant(s).are enclosed, consistent with the commi1ment following l;he NUPIC audit in early 1999. Peak Clad Templ;lrature. (PCT) sheets are enclosed. All necessary revisions for any non"zero, non-discretionaty PCT changes have been included. Non-discretionary PCT impacts of oop will generally not be presented on the PCT sheet The Evaluation Model changes and errors (except any plant-specific errors in the application ofthe model) will be provided to the NRC via Westinghouse letter.

This information is for your use in making a detenninatiop. 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 (PCB), Danial Utley (412-3 7 4-6663 ), ifthere are any questions concerning tlus information.

Author: (Electronically Approved)* Verified: (Electronically Approved)*

Heather McMillen Danial W. Utley LOCA Integrated Services 11 LOCA Integrated Services 11 Approved: (Electronically Approved)*

Matthew B. Cerrone Manager1 LOCA Integrated Services 11

Attachment:

10 CFR 50.46 Reporting Text and PCT Summary Sheets (9 Pages)

• E/ech'oltlcally approved records are authenticated In tlze electronic document management ,s*ystem.

© 2017 Westinghouse Electric Company LLC All Rights Reserved Page4

Attachment to LTR-LIS-17-45 February 8, 2017 Page 1 of9 GENERALCODENUUNTENANCE

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 defmitions, 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 ofWCAP-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 The nature of these changes leads to an estimated Peak Cladding Temperature (PCT) impact of0°F.

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Attachment to LTR-LIS-17-45 Februaty 8, 2017 Page 2 of9 ERROR IN OXIDATION CALCULATIONS .

Background .

A closely-related group of errors were discovered in the WCOBRA/IRAC software program. The en*ors are related to the calculation of high temperature oxidation within a realistic large break loss-of-coolant accident (LOCA) calculation. This issue has been evaluated to estimate the impact on the Automated Statistical Treatment of Uncertainty Method (ASTRIJM) and the Best-Estimate (BE) Large-Brealc Loss-of-Coolant .Accident (LBLOCA) licensing-basis analysis results. The resolution of this issue represents a Non-Discretionary Cha~ge in accordance with Section 4.1.2 ofWCAP-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 It was determined that correcting the high temperature oxidation calculation in WCOBRA/TRAC is estimated to have a negligible. impact on the BE LBLOCA peal( ciadding temperature (PCT) analysis results, leading to an estimated PCT impact of0°F for 10 CFR 50.46 repmting purposes.

• L..~

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February 8, 2017 i>age 3 of9 ERROR IN USE OF ASME STEAM TABLES Background ,

The American Society of Mechanical Engineers (ASME) steam tables are used to calculate the steady-state upper head liquid temperature as a function of the pressure and. specific enthalpy in the ASTRUM software program. The steam table applicable to steam/gas is used to determine the upper head fluid temperature. However, the* water in the upper head is in the sub cooled liquid state during normal operation (and the steady-state calculation). Therefore, the steam table applicable to liquid should be used to determine the upper head fluid temperature. This issue has been evaluated to estimate the impact on Automated Statistical Treatment of Uncertainty Method (ASTRUM) Best-Estimate (BE) Large-Break Loss-of-Coolant Accident (LBLOCA) analysis results. The resolution of this issue represents a Non-Discretionaty Change in accordance with Section 4.1.2 ofWCAP-13451.

Affected Evaluation Model(s) 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using A STRUM Estimated Effect It was detetmined that the temperatures calculated by the ASJYIE steam tables applicable to the steam/gas side and the liquid side are very similat* within the typical upper head pressure and liquid specific en~alpy ranges. Therefore, this error was evaluated to have a negligible impact on the ASTR(JM BE LBLOCA analysis results, leading to an estimated PCT impact of 0°F for 10 CFR 50.46 reporting purposes.

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Attachment to LTR~LIS-17-45 Febma:ry 8, 2017 Page4 of9 PRAIRIE ISLAND UNITS 1 AND 2 UPPER PLENUM FLUID VOLUME .

Background

The upper plenum fluid volume modeled in the small-break loss-of-coolant accident (SBLOCA) analysis for P:t:airie Island Units 1 and 2 was found to be underpredicted. The resolution of this issue represents a Non-Discretionary Change to the Evaluation Model as described in Section 4.1.2 of.WCAP-13451.

Affected Evaluation Model(s) 1985 Westinghouse SmallBreakLOCA Evaluation Model withNOTRUMP Estimated Effect A qualitative evaluation was perfmmed which concluded that the change in upper plenum fluid volume has a negligible impact on the small break LOCA analysis results, leading to an estimated Peale Cladding Temperature (PCT) impact of 0°F.

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Attachment to L TR~LIS~ 17-45 February 8, 2017 Page 5 of9 Westinghouse LOCA Peale Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: Prairie Island Unit 1 Utility Name: Xcel Energy, Inc Revision Date: 2/8/2017 Analysis Information EM: ASTRUM (2004) Analysis Date: 11/30/2007 Limiting Break Size: Split FQ: 2.5 FdH: 1.7.7 Fuel: 422 Vantage+ SGTP(%): 10 Notes:

Clad Temp (0 F) Ref. Notes LICENSING BASIS Analysis~Of~Record PCT 1765 1 PCT ASSESSMENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS 1 . Evaluation of Fuel Pellet Thermal Conductivity Degradat!onand Peaking 227 2 (a)

Factor Bumdown 2 . Revised Heat Transfer Multiplier Distributions -2 3 3 . Errorin Burst Strain Application 25 4 B. PLANNED PLANT MODIFICATION EVALUATIONS 1

• None 0 C. 2016 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 Acoident for Prairie Island Units 1 and 2 with Replacement Steam Generators Using ASTRUM Methodology," June 2013.

2 . LTR-LIS-12-414, "Prairie Island Units 1 and 2, 10 CFR50.46 Notification and Reporting for Fuel PelletThennal Conductivity Degradation and Peaklng Fac.tor Bumdown," September 20, 2012.

3 . LTR-LIS-13-366, Revision 1, "Prairie Island Units 1 and2 10 CFR 50.46 Report for Revised Heat Transfer Multiplier Distributions, 11 August 2013.

4 . LTR-LIS-14-50, "Prairle Island Units 1 and 210 CFR 50.46 Report fur the HOTSPOT Burst Strain Error Correction,"

January 2014.

Notes:

(a) This evaluation credits peaking factor bumdown, see Refere~ce 2.

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Attachment to LTR"LIS"l7-45 s; February 2017 Page 6 of9 Westinghouse .LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Prairie Island Unit 1 Utility Name: Xcel Energy, Inc Revision Date: 2/8/2017 Analysis Information EM: NOTRUMP Analysis Da.te: 1/21/2008 Limiting Break Size: 3lnch FQ: 2.5 FdH: 1.77 Fueli 422 Vantage+ SGTP (%): 10 Notes: Zirlo (14X14), Fi:amatome RSG Clad Temp (OF) Ref. Notes LICENSING BASIS Analysis"Of-Record PCT 959 1.

PCT ASSESSJ.Y.IENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSJ.Y.IENTS 1 . None 0 B.. PLANNED PLANT MODIFICATION EVALUATIONS

. 1 . None 0 C. 2016 ECCS MODEL ASSESSJ.Y.IENTS 1 .None 0 D. OTBER*

1 . 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 CPR 50.46 reporting requirements.

References

. 1 . LTR-LIS-08-158, "Transmittal ofFulure Prairie Island Units 1 and 2 PCT Summaries," February 2008.

Notes:

None Page 10

Attachment to LTR:-LIS-17-45 Febtuazy 8, 2017 Page? of9 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: 2/8/2017 Analysis Information EM:

• ASTRUM (2004) Analysis Date: 11/30/2007 Limiting Break Size: Split FQ: 2.5 FdH: L77 Fuel: 422 Vantage+ SGTP (%): 10 Notes:

Clad Temp (°F) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1765 :1 PCT ASSESSMENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS 1 . Evaluation of Fuel Fellet Thermal Conductivity Degradation and Feaking '127 2 (a), (b)

Factor Bumdown 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. 2016 ECCS MODEL ASSESSMENTS 1 . None 0 D. OTHER*

1 . None 0 LICENSING BASIS PCT + PCT ASSESSIY.lENTS PCT;, 2015

• It is recommended that the licensee determine if these PCT allocations should be considered with respect to I 0 CPR 50.46 rep_orting requirements.

References I . WCAP-I7783-P, "Best-Estimate Analysis of the Large-Break Loss-of.CoolantAccident for Prairie Island Units 1 and 2 with Replacement Stearn Generators Using ASTRUM MethodolOgy," June 20 I3, 2 . LTR-LIS-12414, "Prairie Island Units 1 and 2, 10 CFR 50.46 Notification and Reporting fur Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown," September 20, 20I2.

3 , L1R-LIS-13-366, Revision 1, "Prairie Island Units I 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 bumdown, see Reference 2, (b) The reporting text and line item originally identified for Unit 1 in Reference 2ls applicable to Unit 2 with RSGs.

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Attachment to LTR:-LIS-17-45 February 8, 2017 Page 8 of9 Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: Prairie Island Unit 2 Utility Name: Xcel Energy, Inc Revision Date: 2/8/2017 Analysis Information EM: NOTRUMP Analysis Date: 1/21/2008 Limiting Brealc Size: 3 inch FQ: 2.5 FdR: 1.77 Fuel: 422 Vantage+ SGTP (%): 10 Notes: Zirlo (14Xl4), AREVARSG Clad Temp (OF) 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 1 . None 0 C. 2016 ECCS MODEL ASSESSMENTS 1 . None 0 D. OTHER*

1 . None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT'== 959

• It is recommended that the lic'ensee detennine 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 1 and 2, 10 CPR 50.46 Summary Sheets for the Evaluation to SUpport the Unlt2 Installation of AREVA Model 56/19 Replacement Steam Generators (RSGs)," June 2013 ..

Notes:

(a) The Unit 1 AOR is applicable to Unit 2 with the RSGs installed.

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Attachment to LTR-LIS-17-45 February 8, 2017 Page 9 of9 10 C)fR 50.46 Reporting SharePoint Site* Check:

EMs* applicable fo Prairie lsl~md: .

Realistic Large Break- ASTRUM (2004)

Appendix K Small Break- NQTR1JMI>

2016Issues Transmittal Letter . Issue Description LTR-LIS-16-444 10 CPR 50.46 Reporting Text for Incorrect LUCIFER2 Upper Plenum Fluid Volume for Prairie Island Units 1 and 2 (NSPINRP)

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