ML13199A279
| ML13199A279 | |
| Person / Time | |
|---|---|
| Site: | Mcguire, Catawba, McGuire  |
| Issue date: | 07/11/2013 |
| From: | Annacone M J Duke Energy Carolinas |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML13199A279 (11) | |
Text
DUKE Michael J. Annacone526 South Church StreetCharlotte, NC 28202ENERGY.Oaoo.
80Mailing Address:Mail Code EC07H / P.O. Box 1006Charlotte, NC 28201-1006 Office: 980-373-2544 Fax: 704-382-6056 MichaeI.Annacone@duke-energy.com 10 CFR 50.410 CFR 50.46July 11, 2013U. S. Nuclear Regulatory Commission Attn: Document Control DeskWashington, DC 20555-0001 Catawba Nuclear Station, Units 1 and 2Docket Numbers 50-413 and 50-414/Renewed License Numbers NPF-35 and NPF-52McGuire Nuclear Station, Unit 1 and 2Docket Numbers 50-369, and 50-370/Renewed License Numbers NPF-9 and NPF-1 7
Subject:
Duke Energy Carolinas, LLC (Duke Energy):
Report Pursuant to 10 CFR 50.46,Changes to or Errors in an Evaluation Model
References:
- 1) Letter, D. C. Culp (Duke Energy) to USNRC,
Subject:
Catawba Nuclear Station Units 1 and2, and McGuire Nuclear Station Units 1 and 2, Response to Information Request Pursuantto 10 CFR 50.54(f)
Related to the Estimated Effect on Peak Cladding Temperature Resulting from Thermal Conductivity Degradation in the Westinghouse-Furnished Realistic Emergency Core Cooling System Evaluation and 30-Day Report Pursuant to 10 CFR 50.46,Changes to or Errors in an Evaluation Model," March 16, 2012. [ADAMS ML1 2079A1 80]2) Letter, J. Thompson (USNRC) to K. Henderson and S. D. Capps (Duke Energy),
Subject:
Catawba Nuclear Station Units 1 and 2, and McGuire Nuclear Station Units 1 and 2, ClosureEvaluation for Report Pursuant to Title 10 of the Code of Federal Regulations, Part 50,Section 50.46, Paragraph (a)(3)(ii)
Concerning Significant Emergency Core Cooling SystemEvaluation Model Error Related to Nuclear Fuel Thermal Conductivity Degradation (TACNos. ME8447, ME8448, ME8449, and ME8450)"
November 16, 2012 [ADAMSML12314A031]
10 CFR 50.46 (a)(3)(ii) requires the reporting of changes to or errors in Emergency CoreCooling (ECCS) evaluation models (EMs). This report covers the time period from January 1,2012 to December 31, 2012 for the Catawba Nuclear Station (CNS) and the McGuire NuclearStation (MNS).
U.S. Nuclear Regulatory Commission July 11,2013Page 2The impacts to Large Break Loss of Coolant Accident (LBLOCA) peak cladding temperature (PCT) due to fuel pellet thermal conductivity degradation were previously reported to the NRC inReference
- 1. NRC staff review and acceptance of the impact to PCT due to fuel pellet thermalconductivity degradation was documented in Reference
- 2. These impacts to the LOCAanalyses are discussed in Table 1, and are included on the PCT reporting sheets, Tables 2through 4.Several other changes were made to the LBLOCA and Small Break LOCA evaluation modelsduring the reporting period. The specific details of these changes are also provided in Table 1,and were evaluated by Westinghouse as having no impact on the calculated PCTs. Since therewas no PCT impact due to these changes, they are not included in the PCT reporting sheets,Tables 2 through 4.There are no regulatory commitments contained in this letter.Please address any comments or questions regarding this matter to Paul Guill at(704) 382-4753 (paul.guill@duke-energy.
corn).Sincerely, Michael J. Annacone, Vice President
-Organizational Effectiveness
&Regulatory AffairsAttachment Table 1 -Errors/Evaluation Model ChangesTable 2 -Peak Cladding Temperature Summary -McGuire Units 1 & 2Table 3 -Peak Cladding Temperature Summary -Catawba Unit 1Table 4 -Peak Cladding Temperature Summary -Catawba Unit 2 U.S. Nuclear Regulatory Commission July 11,2013Page 3xc (with attachment):
V. M. McCree, Region II Administrator U.S. Nuclear Regulatory Commission Marquis One Tower245 Peachtree Center Avenue NE, Suite 1200Atlanta, GA 30303-1257 J. C. Paige, Senior Project Manager (CNS & MNS)U. S. Nuclear Regulatory Commission 11555 Rockville PikeMail Stop 0-8C2ARockville, MD 20852-2738 J. Zeiler, NRC Senior Resident Inspector McGuire Nuclear StationG. A. Hutto, NRC Senior Resident Inspector Catawba Nuclear Station ATTACHMENT Table 1 -Errors/Evaluation Model ChangesTable 2 -Peak Cladding Temperature Summary -McGuire Units 1 & 2Table 3 -Peak Cladding Temperature Summary -Catawba Unit 1Table 4 -Peak Cladding Temperature Summary -Catawba Unit 2
References:
A) Letter, M. S. Tuckman (Duke Energy) to USNRC, "Report Pursuant to 10 CFR 50.46,Changes to or Errors in an ECCS Evaluation Model," May 3, 2001B) Letter, M. S. Tuckman (Duke Energy) to USNRC, "Report Pursuant to 10 CFR 50.46,Changes to or Errors in an ECCS Evaluation Model," April 3, 2002C) Letter, W. R. McCollum, Jr. (Duke Energy) to USNRC, "Report Pursuant to 10 CFR 50.46,Changes to or Errors in an ECCS Evaluation Model," July 29, 2003D) Letter, W. R. McCollum, Jr. (Duke Energy) to USNRC, "Report Pursuant to 10 CFR 50.46,Changes to or Errors in an ECCS Evaluation Model," May 26, 2004E) Letter, J. R. Morris (Duke Energy) to USNRC, "Report Pursuant to 10 CFR 50.46, Changesto or Errors in an ECCS Evaluation Model," June 21, 2005F) Letter, T. C. Geer (Duke Energy) to USNRC, "Report Pursuant to 10 CFR 50.46, Changes toor Errors in an ECCS Evaluation Model," March 13, 2007.G) Letter, D. C. Culp (Duke Energy) to USNRC,
Subject:
Catawba Nuclear Station Units 1 and2, and McGuire Nuclear Station Units 1 and 2, Response to Information Request Pursuantto 10 CFR 50.54(f)
Related to the Estimated Effect on Peak Cladding Temperature Resulting from Thermal Conductivity Degradation in the Westinghouse-Furnished Realistic Emergency Core Cooling System Evaluation and 30-Day Report Pursuant to 10 CFR 50.46,Changes to or Errors in an Evaluation Model," March 16, 2012. [ADAMS ML1 2079A1 80]H) Letter, J. Thompson (USNRC) to K. Henderson and S. D. Capps (Duke Energy),
Subject:
Catawba Nuclear Station Units 1 and 2, and McGuire Nuclear Station Units 1 and 2, ClosureEvaluation for Report Pursuant to Title 10 of the Code of Federal Regulations, Part 50,Section 50.46, Paragraph (a)(3)(ii)
Concerning Significant Emergency Core Cooling SystemEvaluation Model Error Related to Nuclear Fuel Thermal Conductivity Degradation (TACNos. ME8447, ME8448, ME8449, and ME8450)"
November 16, 2012. [ADAMSML12314A031]
Page 1 of 8 Table 1Errors / Evaluation Model ChangesEvaluation of Fuel Pellet Thermal Conductivity Degradation and Peaking FactorBurndownFuel pellet thermal conductivity degradation (TCD) and peaking factor burndown were notexplicitly considered in the Large Break Loss-of-Coolant Accident (LBLOCA)
Analysis of Record(AOR) for McGuire Units 1 & 2 and Catawba Units 1 & 2. The Nuclear Regulatory Commission (NRC) requested Duke Energy to provide an estimated effect of TCD on the peak claddingtemperature (PCT) calculation for the emergency core cooling system at McGuire Units 1 & 2and Catawba Units 1 & 2.Affected Evaluation Model(s):
BELOCA 1996 ModelA quantitative evaluation as discussed in Reference 2 was performed to assess the PCT effectof TCD and peaking factor burndown with other considerations of burnup on the LBLOCAanalysis for McGuire Units 1 & 2 and Catawba Units 1 & 2, and concluded that the estimated PCT impact is +1 140F for Reflood 1 and +1 5°F for Reflood 2 for 10 CFR 50.46 reporting purposes.
PAD Version 4.0 Implementation The Large Break Loss-of-Coolant Accident (LBLOCA)
Analysis of Record (AOR) for McGuireUnits 1 & 2 and Catawba Units 1 & 2 utilizes fuel rod design inputs from PAD Version 3.4. Priorto explicitly considering fuel pellet thermal conductivity degradation (TCD) and peaking factorburndown, fuel rod design input with PAD Version 4.0 was implemented in order to estimate aneffect of fuel pellet TCD that does not include unrelated PAD code version differences.
Theplant-specific implementation of PAD 4.0 into the LBLOCA AOR for McGuire Units 1 & 2 andCatawba Units 1 & 2 is considered a design input change into the LBLOCA analysis.
Affected Evaluation Model(s):
BELOCA 1996 ModelA quantitative evaluation was performed to estimate a PCT impact resulting from a change infuel rod design input parameters from PAD 3.4 to PAD 4.0. The evaluation concluded that theestimated PCT impact is -750F for Reflood 1 and Reflood 2 for 10 CFR 50.46 reporting purposes.
Page 2 of 8 General Code Maintenance Affected Evaluation Model(s):
BELOCA 1996 ModelVarious changes have been made to enhance the usability of codes and to streamline futureanalyses.
Examples of these changes include modifying input variable definitions, units anddefaults; improving the input diagnostic checks; enhancing the code output; optimizing activecoding; and eliminating inactive coding. These changes represent Discretionary Changes thatwill be implemented on a forward-fit basis.The nature of these code changes leads to an estimated Peak Cladding Temperature (PCT)impact of 0°F.HOTSPOT Burst Temperature Calculation for ZIRLO CladdingAffected Evaluation Model(s):
BELOCA 1996 ModelA problem was identified in the calculation of the burst temperature for ZIRLO cladding in theHOTSPOT code when the cladding engineering hoop stress exceeds 15,622 psi. This problemresults in either program failure or an invalid extrapolation of the burst temperature vs.engineering hoop stress table. This problem has been evaluated for impact on existinganalyses, and its resolution represents a Non-Discretionary Change.The evaluation of existing analyses demonstrated no impact on the overall PCT results, leadingto an estimated effect of 0°F.HOTSPOT Iteration Algorithm for Calculating the Initial Fuel Pellet Average Temperature Affected Evaluation Model(s):
BELOCA 1996 ModelThe HOTSPOT code has been updated to incorporate the following corrections to the iteration algorithm for calculating the initial fuel pellet average temperature:
(1) bypass the iteration whenthe input value satisfies the acceptance criterion; (2) prevent low-end extrapolation of the gapheat transfer coefficient; (3) prevent premature termination of the iteration that occurred undercertain conditions; and (4) prevent further adjustment of the gap heat transfer coefficient afterreaching the iteration limit. These changes represent a closely-related group of Non-Discretionary Changes.Sample calculations and engineering judgment lead to an estimated PCT impact of 0°F.Page 3 of 8 WCOBRAITRAC Automated Restart Process Logic ErrorAffected Evaluation Model(s):
BELOCA 1996 ModelA minor error was identified in the WCOBRAITRAC Automated Restart Process (WARP) logicfor defining the Double-Ended Guillotine (DEG) break tables. The error has been evaluated forimpact on current licensing-basis analysis results and will be incorporated into the plant-specific analyses on a forward-fit basis. These changes represent a closely-related group of Non-Discretionary Changes in accordance with Section 4.1.2 of WCAP-1 3451.These errors were evaluated to have a negligible impact on the Large Break LOCA analysisresults, leading to an estimated PCT impact of 0°F.Rod Internal Pressure Calculation Affected Evaluation Model(s):
BELOCA 1996 ModelSeveral issues which affect the calculation of rod internal pressure (RIP) have been identified for certain Best-Estimate (BE) Large-Break Loss-of-Coolant Accident (LBLOCA) evaluation models (EMs). These issues include the sampling of rod internal pressure uncertainties, updating HOTSPOT to consider the effect of transient RIP variations in the application of theuncertainty, and generating RIPs at a consistent rod power. These issues have been evaluated to estimate the impact on existing LBLOCA analysis results.
The resolution of these issuesrepresents a closely-related group of Non-Discretionary Changes.The effects described above are either judged to have a negligible effect on existing LBLOCAanalysis results or have been adequately incorporated into the thermal conductivity degradation evaluations, leading to an estimated PCT impact of 0°F.WCOBRA/TRAC Thermal-Hydraulic History File Dimension Used in HSDRIVERAffected Evaluation Model(s):
BELOCA 1996 ModelA problem was identified in the dimension of the WCOBRA/TRAC thermal-hydraulic history fileused in HSDRIVER.
The array that is used to store the information from the WCOBRAITRAC thermal-hydraulic history file is dimensioned to 3000 in HSDRIVER.
It is possible for this file tocontain more than 3000 curves. If that is the case, it is possible that the curves would not beused correctly in the downstream HOTSPOT execution.
An extent-of-condition review indicated that resolution of this issue does not impact the Peak Cladding Temperature (PCT) calculation for prior Large Break Loss-of-Coolant Accident (LBLOCA) analyses.
This represents aDiscretionary Change.Resolution of this issue does not impact the PCT calculation for prior LBLOCA analyses, whichleads to a PCT impact of 0°F.Page 4 of 8 NOTRUMP-EM Evaluation of Fuel Pellet Thermal Conductivity Degradation Affected Evaluation Model(s):
SBLOCA, 1985 NOTRUMP ModelAn evaluation has been completed to estimate the effect of fuel pellet thermal conductivity degradation (TCD) on peak cladding temperature (PCT) for plants in the United States withanalyses using the 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP(NOTRUMP-EM).
This change represents a Non-Discretionary Change.Based on the phenomena and physics of the SBLOCA transient, in combination with limitedsensitivity calculations, it is concluded that TCD has a negligible effect on the limiting claddingtemperature transient, leading to an estimated PCT impact of 0°F.Page 5 of 8 Table 2Peak Cladding Temperature Summary -McGuire Units 1 & 2LBLOCA Cladding Temp Comments(OF)Evaluation model: WCOBRA/TRAC, CQD 1996MNS/CNSAnalysis of record PCT (Reflood
- 2) 2028 Composite ModelPrior errors (APCT)1. Decay heat in Monte Carlo calculations 8 Reference A2. MONTECF power uncertainty correction 20 Reference B3. Safety Injection temperature range 59 Reference C4. Input error resulting in an incomplete solution matrix 25 Reference D5. Revised Blowdown Heatup Uncertainty Distribution 5 Reference E6. Vessel Unheated Conductor Noding 0 Reference FPrior evaluation model changes (APCT)1. Revised Algorithm for Average Fuel Temperature 0 Reference FErrors (APCT)1. Thermal Conductivity Degradation with Peaking 15 Reference GFactor BurndownEvaluation model changes (APCT)1. PAD 3.4 to PAD 4.0 -75 Reference G2. MUR Uprate to 101.7% of 3411 MWt 163. Peak FQ = 2.7 in bottom third of core 0Absolute value of errors/changes for this report (APCT) 106Net change in PCT for this report -44 Reference GFinal PCT 2101SBLOCAEvaluation model: NOTRUMPAnalysis of record PCT 1323 2 inch breakPrior errors (APCT)1. None 0Prior evaluation model changes (APCT)1. None 0Errors (APCT)1. Evaluation of Fuel Pellet Thermal Conductivity 0Degradation Evaluation model changes (APCT)1. None 0Absolute value of errors/changes for this report (APCT) 0Net change in PCT for this report 0Final PCT 1323Page 6 of 8 Table 2Peak Cladding Temperature Summary -Catawba Unit ILBLOCA Cladding Temp Comments(OF)Evaluation model: WCOBRA/TRAC, CQD 1996MNS/CNSAnalysis of record PCT (Reflood
- 2) 2028 Composite ModelPrior errors (APCT)1. Decay heat in Monte Carlo calculations 8 Reference A2. MONTECF power uncertainty correction 20 Reference B3. Safety Injection temperature range 59 Reference C4. Input error resulting in an incomplete solution matrix 25 Reference D5. Revised Blowdown Heatup Uncertainty Distribution 5 Reference E6. Vessel Unheated Conductor Noding 0 Reference FPrior evaluation model changes (APCT)1. Revised Algorithm for Average Fuel Temperature 0 Reference FErrors (APCT)1. Thermal Conductivity Degradation with Peaking 15 Reference GFactor BurndownEvaluation model changes (APCT)1. PAD 3.4 to PAD 4.0 -75 Reference G2. Peak FQ = 2.7 in bottom third of core 0Absolute value of errors/changes for this report (APCT) 90Net change in PCT for this report -60 Reference GFinal PCT 2085SBLOCAEvaluation model: NOTRUMPAnalysis of record PCT 1323 2 inch breakPrior errors (APCT)1. None 0Prior evaluation model changes (APCT)1. None 0Errors (APCT)1. Evaluation of Fuel Pellet Thermal Conductivity 0Degradation Evaluation model changes (APCT)1. None 0Absolute value of errors/changes for this report (APCT) 0Net change in PCT for this report 0Final PCT 1323Page 7 of 8 Table 3Peak Cladding Temperature Summary -Catawba Unit 2LBLOCA Cladding Temp Comments(OF)Evaluation model : WCOBRA/TRAC, CQD 1996MNS/CNSAnalysis of record PCT (Reflood
- 2) 2028 Composite ModelPrior errors (APCT)1. Decay heat in Monte Carlo calculations 8 Reference A2. MONTECF power uncertainty correction 20 Reference B3. Safety Injection temperature range 59 Reference C4. Input error resulting in an incomplete solution matrix 25 Reference D5. Revised Blowdown Heatup Uncertainty Distribution 5 Reference E6. Vessel Unheated Conductor Noding 0 Reference FPrior evaluation model changes (APCT)1. Revised Algorithm for Average Fuel Temperature 0 Reference FErrors (APCT)1. Thermal Conductivity Degradation with Peaking 15 Reference GFactor BurndownEvaluation model changes (APCT)3. PAD 3.4 to PAD 4.0 -75 Reference G4. Peak FQ = 2.7 in bottom third of core 0Absolute value of errors/changes for this report (APCT) 90Net change in PCT for this report -60 Reference GFinal PCT 2085SBLOCAEvaluation model: NOTRUMPAnalysis of record PCT 1243 4 inch breakPrior errors (APCT)1. None 0Prior evaluation model changes (APCT)1. None 0Errors (APCT)1. Evaluation of Fuel Pellet Thermal Conductivity 0Degradation Evaluation model changes (APCT)1. None 0Absolute value of errors/changes for this report (APCT) 0Net change in PCT for this report 0Final PCT 1243Page 8 of 8