ML14119A332

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10 CFR 50.46 - Annual Report for 2013
ML14119A332
Person / Time
Site: Watts Bar  Tennessee Valley Authority icon.png
Issue date: 04/25/2014
From: Church C
Tennessee Valley Authority
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML14119A332 (13)
v • d • e


Text

Tennessee Valley Authority, Post Office Box 2000, Spring City, Tennessee 37381-2000 April 25,2014 10 cFR 50.46 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Units 1 and2 Facility Operating License No. NPF-90 Construction Permit No. CPPR-92 NRC Docket Nos. 50-390 and 50-391

Subject:

10 CFR 50.46 - Annual Report for 2013 for Watts Bar, Units 1 and 2

Reference:

1. TVA Letter to NRC, '10 CFR 50.46 Day and Annual Report tor 2012,"

dated April 25, 2013 [MLl3120A005]

2. Letter from TVA to NRC, "10 CFR 50.46 - 30 day Report for Watts Bar, Unit 1," dated August 28,2013 [M1132674034]
3. Letter from TVA to NRC, "Watts Bar Nuclear Plant, Unit 2 - Emergency Core Cooling System Evaluation Model Changes - 30 Day Report - 10 CFR 50.46 Notification," dated August 28, 2013 [M113246A076]
4. TVA Letterto NRC,'10 CFR 50.46 Day ReportforWatts Bar, Units 1 and2," dated February 28,2014 [ML14064A431]

The purpose of this letter is to provide an annual report of changes and errors to the calculated peak cladding temperature (PCT) for the Watts Bar Nuclear Plant WBN), Units 1 and2, Emergency Core Cooling System (ECCS) evaluation models. This report is required in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.46, "Acceptance Criteria for Emergency Core Cooling Systems for Light-Water Nuclear Power Reactors,"

paragraph (aX3Xii).

The enclosure to this letter provides a summary of the changes and errors to the calculated PCTs for the limiting ECCS analyses, including the changes made since the submittal of the previous annual report (Reference 1) and subsequent 30-day reports (References 2, 3, and 4) forWBN Units 1 and2.

U.S. Nuclear Regulatory Commission Page2 April25,2014 As indicated in the enclosure, the current updated (net) licensing basis PCT for the WBN, Unit 1, Large Break Loss of Coolant Accident (LBLOCA) analysis of record (AOR) is now estimated to be 1865oF, a 1SoF decrease from the previous annual report. The updated (net) licensing basis PCT for the Small Break LOCA (SBLOCA) evaluation model is unchanged from the SBLOCA AOR baseline PCT, and remains at 1132"F.

As indicated in the enclosure, the current updated (net) licensing basis PCT for the WBN, Unit 2, LBLOCA AOR is now estimated to be 171'1"F, a change of -16'F from the last annual report (Reference 1). The updated (net) licensing basis PCT for the SBLOCA evaluation model is unchanged from the SBLOCA AOR baseline PCT, and remains at 1184'F.

The enclosed reports demonstrate that the calculated PCTs forthe ECCS LBLOCA and SBLOCA AORs forWBN, Units 1 and2, are below the limit of 22O0"F. This provides the requisite demonstration of compliance with the 10 CFR 50.46 requirements. Therefore, no schedule for reanalysis or other action to show compliance is required.

There are no regulatory commitments in this letter. Please direct questions concerning this report to Gordon Arent d @23) 365-2004.

Respectfull KK Site Vice President Watts Bar Nuclear Plant

Enclosure:

Watts Bar Nuclear Plant, Units 1 and2,10 CFR 50.46 Annual Report cc (Enclosure):

NRC RegionalAdministrator - Region ll NRC Senior Resident lnspector - Watts Bar Nuclear Plant Unit 1 NRC Senior Resident lnspector - Watts Bar Nuclear Plant Unit 2 NRC Project Manager - Watts Bar Nuclear Plant Unit 1 NRC Project Manager - Watts Bar Nuclear Plant Unit 2 EDMS

ENCLOSURE 1 WATTS BAR NUCLEAR PLANT, UNITS { AND 2 l0 CFR 50.46 Annual Report for 2013

!n accordance with the reporting requirements of Title 10 of the Code of Federal Regulations (10 CFR) 50.a6(a)(3)(ii), the following is a summary of the limiting design basis loss of coolant accident (LOCA) analysis results established using the cunent Watts Bar Nuclear Plant (WBN)

Emergency Core Cooling System (ECCS) evaluation models for Units 1 and 2. This report describes the changes and errors affecting the calculated peak cladding temperatures (PCTs) since the last annual report.

The last 10 CFR 50.46 annual report forWBN Unit 1 was submitted to the United States Nuclear Regulatory Commission (NRC) on April 25,2013 (Reference 1). A 10 CFR 50.46 -

30 day report for WBN Unit 1 was submitted on August 28, 2013 (Reference 13) and on February 28, 2014 (Reference 17). As indicated in these previous reports, Westinghouse Electric Company WEC) WCAP-14839, Revision 1, "Best Estimate Analysis of the Large Break Loss of Coolant Accident for the Watts Bar Nuclear Plant' (Reference 2), is the cunent Best Estimate Large Break LOCA (BE LBLOCA) analysis of record (AOR) for Unit 1, with a baseline PCT value of 1892"F. This baseline PCT for the previous annual report corresponds to the Reflood 2 (late reflood) case. For this annual report, both Reflood 1 (early reflood) and Reflood 2 results are reported. The Reflood 1 case has a baseline PCT value of 1656'F. The current Smal! Break LOCA (SBLOCA) AOR for Unit 1 is WW-RSG-06-015, "LOCA & Non-LOCA Analysis Summary for Replacement Steam Generato/' (Reference 3) for WBN Unit 1, with a baseline PCT of 1132"F.

The last 10 CFR 50.46 annua! report for WBN Unit 2 was submitted to the NRC on April 25, 2013 (Reference 1). As indicated in this previous report, WEC WCAP-17093-P,"Best Estimate Analysis of the Large Break Loss of Coolant Accident for the Watts Bar Unit 2 Nuclear Plant Using the ASTRUM Methodology" (Reference 18), was the BE LBLOCA AOR for Unit 2, with a baseline PCT value ol 1727"F. However, since that report, Reference 19 established WCAP-17093, Revision 1 (Reference 14) to be the current AOR for Unit 2, with a baseline PCT value of 1766oF. 10CFR50.46 - 30 day reports were submitted on August 28,2013 (Reference 16) and on February 28, 2014 (Reference 17) that utilized WCAP-17093, Revision 1 , as the AOR for Unit 2. The cunent SBLOCA AOR for Unit 2 is WBT-D-1460, "Fina! Small Break LOCA Summary Report forWBN Unit 2" (Reference 15), with a baseline PCT of 11U"F.

Tables 1, 2, and 3 detail the accumulated PCT effects resulting from the changes and errors in the LBLOCA and SBLOCA analyses since each of the respective AORs (References 2, 3, 14 and 15) were established forWBN Units 1 and2. There have been no changes or errors since the last 30-day report (Reference 17).

As indicated in Table 1 for WBN Unit 1, the current updated (net) licensing basis PCT for the LBLOCA analysis is 1865'F. This is a 15'F decrease in PCT from the last annua! report (Reference 1). Both the early and late reflood cases are reported in Table 1. The WBN Unit 1 updated (net) licensing basis PCT value of 1132'F for the SBLOCA shown in Table 2 is unchanged from the SBLOCA AOR baseline PCT, as reflected in the previous reports.

As indicated in Table 3 for WBN Unit 2, the current updated (net) licensing basis PCT for the LBLOCA analysis is 1711'F. This is a 16'F decrease in PCT from the last annual report (Reference 1), and a 55'F decrease in PCT from the updated AOR. The WBN Unit 2 updated E-1

ENCLOSURE 1 WATTS BAR NUCLEAR PLANT, UNITS { AND 2 10 CFR 50.46 Annual Report for 2013 (net) licensing basis PCT value of 1184'F for the SBLOCA is unchanged from the SBLOCA AOR baseline PCT, as reflected in the previous reports.

ln accordance with 10 CFR 50.46(aX3)(ii), future changes affecting WBN Units 1 and 2 wi!! be considered significant for reporting purposes because the absolute magnitude of the accumulated changes and errors affecting the calculated PCT since the last LBLOCA re-analysis was performed (References 2 and 14) exceeds 50'F.

E-2

ENCLOSURE 1 WATTS BAR NUCLEAR PLANT, UNITS l AND 2 10 CFR 50.46 Annual Report for 2013 TABLE 1 (Sheet I of 3)

Summary of Changes to WBN Unit I PCT for LBLOCA Reflood 1 Reflood 2 APGT I aecr I APCT lmcrl Year Description ('F) ('F) ("F) ("F) Notes References 1 998 BE LBLOCA AOR Baseline PGT 1 656 1892 2 1 999 Vessel Channel DX Error 56 56 4 4 7 2000 lncreased Accumulator Room 4 4 4 4 7 Temperature Eval uation 2000 1.4% Uprate Evaluation 12 12 12 12 7 2000 Accu m u lator Li ne/Pressu rizer

-37 37 -131 131 7 Surqe Line Data Evaluation 2000 MONTECF Decay Heat 4 4 4 4 8 Uncertaintv Error 2001 WBN Specific LBLOCA Vessel 0 0 0 0 9 Geometry lnput Errors 2003 lnput Error Resulting in 60 60 0 0 10 lncomplete Solution Matrix 2003 Tavg Bias Error 8 I I I 10 2004 lncreased Stroke Time for ECCS 0 0 0 0 11 Valves 2004 Revised Blowdown Heatup 5 5 5 5 11 U ncertaintv Distri bution 2006 Replacement Steam Generators

-50 50 -10 10 12 (D3 to 68AXP) 2006 HOTSPOTTM Fuel Relocation 0 0 65 65 12 Error E-3

ENCLOSURE 1 WATTS BAR NUCLEAR PLANT, UNITS l AND 2 10 CFR 50.46 Annual Report for 2013 TABLE 1 (Sheet 2 of 3)

Summary of Changes to WBN Unit 1 PCT for LBLOCA Reflood 1 Reflood 2 APCT lmcrl APCT lmcrl Year Description ('F) ('F) ("F) ("F) Notes References 2012 PMI D/PBOT Violation Evaluation 20 20 20 20 5,6 2012 TCD and Peaking Factor 114 114 15 15 5,6 Burndown 2013 WCOBRA/TRACTM H istory File 0 0 0 0 4 Dimension Error 2013 Genera! Code Maintenance 0 0 0 0 1 2013 HOTSPOTTM Burst Temperature 0 0 0 0 1 Calculation for ZIRLOTM Claddinq 2013 HOTSPOTTM lteration Algorith m for Calculation lnitial Fuel Pellet 0 0 0 0 1 Averaqe Temperature 2013 WCO B RA/T RACTM Autom ated 0 0 0 0 1 Restart Process Loqic Error 2013 Rod lnternal Pressure Calculation 0 0 0 0 1 Error 2013 Elevations for Heat Slab 0 0 0 0 13 Temperatu re I n itialization 2013 Heat Transfer Model Error 0 0 0 0 13 Corrections 2013 Correction to Heat Transfer Node 0 0 0 0 13 Initialization 2013 Mass Conservation Error Fix 0 0 0 0 13 2013 Correction to Split Channel 0 0 0 0 13 Momentum Equation 2013 Heat Transfer Logic Correction for 0 0 0 0 13 Rod Burst Calculation 2013 Changes to Vessel Superheated 0 0 0 0 13 Steam Properties 2013 Update to Metal Density 0 0 0 0 13 Reference Tem peratu res 2013 Decay Heat Model Error 0 0 0 0 13 Corrections E-4

ENCLOSURE 1 WATTS BAR NUCLEAR PLANT, UNITS { AND 2 10 CFR 50.46 Annual Report for 2013 TABLE 1 (Sheet 3 of 3)

Summary of Ghanges to WBN Unit I PCT for LBLOCA Reflood I Reflood 2 APCT  ! aecr I APCT !mcrl Year Description ('F) ("F) ("F) ('F) Notes References 2013 Correction to the Pipe Exit 0 0 0 0 13 Pressure Drop Error 2013 WCOBRA/TRAC File Dimension 0 0 0 0 13 Error Correction 2013 Revised Heat Transfer Multiplier

-40 40 -85 85 13 Distributions 2014 HOTSPOT Burst Strain Error 20 20 70 70 17 Updated (net) Iicensing basis PCT 1832 1 865 AORPCT+fAPCT Gumulative sum of PCT changes 430 433 r lpcrl E-5

ENCLOSURE 1 WATTS BAR NUCLEAR PLANT, UNITS l AND 2 10 CFR 50.46 Annua! Report for 2013 TABLE2 Summary of Ghanges to WBN Unit { PCT for SBLOCA Year Description SBLOCA SBLOCA Notes References APCT (oF)

!mcrl (oF) 2006 SBLOCA AOR Baseline PGT 1132 3 2013 NOTRUMP-EMrM Evatuation of 0 0 1 Fuel Pellet TCD Updated (net) Iicensing basis PCT 1132 AORPCT+fAPCT Cumulative sum of PCT changes 0 t I apcrl E-6

ENCLOSURE {

WATTS BAR NUCLEAR PLANT, UNITS 1 AND 2 10 CFR 50.46 Annual Report tor 2013 TABLE 3 (Sheet 1 ot 2l Summary of Changes to WBN Unit 2 PCT for LBLOCA and SBLOCA LBLOCA SBLOCA APCT lmcrl APCT lmcrl Year Description ('F) ("F) ("F) ("F) Notes References 2013 BE LBLOGA AOR Baseline PCT 1 766 14 2010 SBLOCA AOR Baseline PCT 1184 15 2013 Elevations for Heat SIab 0 0 0 0 16 Tem peratu re I n itialization 2013 Heat Transfer Model Error 0 0 0 0 16 Corrections 2013 Correction to Heat Transfer Node 0 0 0 0 16 lnitialization 2013 Mass Conservation Error Fix 0 0 0 0 16 2013 Correction to Split Channel 16 0 0 0 0 Momentum Equation 2013 Heat Transfer Logic Correction for 0 0 0 0 16 Rod Burst Calculation 2013 Changes to Vessel Superheated 0 0 0 0 16 Steam Properties 2013 Update to Metal Density 0 0 0 0 16 Reference Tem peratu res 2013 Decay Heat Model Error 0 0 0 0 16 Corrections 2013 Correction to the Pipe Exit 0 0 0 0 16 Pressure Drop Error 2013 WCOBRA/TRAC File Dimension 0 0 0 0 16 Error Correction 2013 Revised Heat Transfer Multiplier

-55 55 0 0 16 Distributions E-7

ENCLOSURE 1 WATTS BAR NUCLEAR PLANT, UNITS 1 AND 2 10 CFR 50.46 Annual Report for 2013 TABLE 3 (Sheet 2 ot 2l Summary of Changes to WBN Unit 2 PCT for LBLOCA and SBLOGA LBLOCA SBLOCA APCT lmcrl APCT Imcrl Year Description ('F) ('F) ("F) ('F) Notes References lnitial Fuel Pellet Average 2013 Tem peratu re U ncertai nty 0 0 0 0 16 Calculation 2014 HOTSPOT Burst Strain Error 0 0 0 0 17 Updated (net) Iicensing basis PCT 1711 1184 AORPCT+fAPCT Gumulative sum of PCT changes 55 0 t lpcrl E-8

ENCLOSURE I WATTS BAR NUCLEAR PLANT, UNITS 1 AND 2 10 CFR 50.46 Annual Report for 20{3 REFERENCES

.10

1. Letter from TVA to NRC, CFR 50.46 Day and Annual Report lor 2012," dated April 25, 2013 [M1131204005]
2. WCAP-14839, Revision 1, "Best Estimate Analysis of the Large Break Loss of Coolant Accident for the Watts Bar Nuclear Plant,' September 1998
3. WTV-RSG-06-015, 'LOCA & Non-LOCAAnalysis Summary for Replacement Steam Generator,' February 2006
4. Letter from TVA to NRC, '10 CFR 50.46 Day Report for Watts Bar Unit 1 ,' dated March 19, 2013 [ML13046A002]
5. Letter from TVA to NRC, "Supplement to 10 CFR 50.46 Day Special Report," dated February 13, 2013 [ML13046A0021
6. Letterfrom TVAto NRC,'10 CFR 50.46 Day Special Report," dated October 1 8, 2012 IML1229642541
7. Letter from TVA to NRC, "Watts Bar Nuclear Plant WBN) Unit 1 - Emergency Core Cooling System (ECCS) Evaluation Model Changes Day Report and Annual Notification and Reporting for 2000,' dated October 26,2O0O [ML003764646]
8. Letter from TVA to NRC, "Watts Bar Nuclear Plant WBN) Unit 1 - Emergency Core Cooling System (ECCS) Evaluation Model Changes Day Report and Revised Annual Notification Report for 2000," dated September 7 ,200'l [ML0125702901
9. Letter from TVA to NRC, "Watts Bar Nuclear Plant WBN) Unit 1 - Emergency Core Cooling System (ECCS) Evaluation Model Changes - Annual Notification and Reporting for 2001," dated April 3, 2002 [ML021O704041
10. Letter from TVA to NRC, "Wafts Bar Nuclear Plant WBN) Unit 1 - Emergency Core Cooling System (ECCS) Evaluation Mode! Changes Day Report and Revised Annual Notification and Reporting for 2003,' dated April 19, 2004 [ML0411301961
11. Letterfrom TVA to NRC, "Watts Bar Nuclear Plant WBN) Unit 1 - Emergency Core Cooling System (ECCS) Evaluation Model Changes - Annual Notification and Reporting lor2004," dated April 19, 2005 [ML0511201641
12. Letter from TVA to NRC, "Watts Bar Nuclear Plant WBN) Unit 1 - Emergency Core Cooling System (ECCS) Evaluation Model Changes Day Report and Annual Notification and Reporting for 2006,' dated July 3, 2007 [ML071860388]

E-9

ENCLOSURE 1 WATTS BAR NUCLEAR PLANT, UNITS 1 AND 2 l0 CFR 50.46 Annual Report for 2013

13. Letter from TVA to NRC, "10 CFR 50.46 - 30 day Report for Watts Bar, Unit 1 ," dated August 28, 2013 [ML13267A034]
14. WCAP-17093-P, Revision 1, 'Best Estimate Analysis of the Large Break Loss of Coolant Accident for the Watts Bar Unit 2 Nuclear Plant Using the ASTRUM Methodology,"

June 2013

15. WBT-D-1460, "Final Small Break LOCA Summary Report forWBN Unit 2,"

January 2010

16. Letter from TVA to NRC, "Watts Bar Nuclear Plant, Unit 2 - Emergency Core Cooling System Evaluation Model Changes - 30 Day Report - 10 CFR 50.46 Notification," dated August 28, 201 3.[ML13246A076]
17. Letter from TVA to NRC, "10 CFR 50.46 - 30 day Report for Watts Bar, Units 1 and2,"

dated February 28, 2014. [ML14064A431 I

18. WCAP-17093-P, "Best Estimate Analysis of the Large Break Loss of Coolant Accident for the Watts Bar Unit 2 Nuclear Plant Using the ASTRUM Methodology," December 2009
19. Letter from TVA to NRC, "Watts Bar Nuclear Plant Unit 2 - Fuel Thermal Conductivity Degradation, Response to Supplemental Safety Evaluation Report Open ltem 61," dated Aug ust 6, 201 3. 1ML1322540241 E-10

CNL-14-066,2013 10 CFR 50.46 Annual Report for WBN I and Z NPG Standard Managing TVA's Interface With NRC NPG.SPP.Os.lO Programs and Rev. 0002 Processes Pase 43 of 62 Attachment 6 (Page 1 of6)

Licensing Submittal Format and Content 1.0 ATTRIBUTES These attributes should be considered during development of a submittal to ensure that the submittal is appropriate for the issue.

A. CORPORATE/SITE LICENSING MANAGER Utilize NPG-SP7-18,2.2, Appendix C, "Human Perfonnance Tools for Managers and Supervisors,"and NLDP-7, "Licensing Personnel Training and Qualification." [49061 1-042 and -016J d Complete NPG-SPP{3.10-2 conespondence review form and return to appropriate Management Assistant for filing in the document management system" Actions noted on NPG-SPP-03.10-2 form should be consistent with intended action. [49061 1-0421 B. BASIS FOR SUBMITTAL Vt* NPG-SPP-03.10-2 conespondence review completed, filed in the document management system, and consistent with intended action.

Detailed review of NRC conespondence complete and all requirements for response identified.

C. FORMAT V{ The standard font for licensing submittials is "Arial." The standard font size is 1'1. Different fonts or sizes may be used when appropriate, but fonts and sizes used shall ensure legibility of the document.

w The standard forrnat for licensing submittal letters should follow the Correspondence Guidelines located on the Licensing homepage under "Correspondence Guidel ines."

D. COVER LETTER should include the following attributes and features (as applicable):

tr Free of grammatical, spelling, and typographical errors.

tr Regulations providing the basis for the submittal annotated in the upper right corner of the submittal cover letter.

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