ML13094A075

CFR 50.46 Annual ECCS Report

ML13094A075
Person / Time
Site:	Ginna
Issue date:	04/01/2013
From:	Mogren T Constellation Energy Group, EDF Group, Ginna
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML13094A075 (17)

Text

Thomas G. Mogren Manager - Engineering Services CENG a joint venture of R.E. Ginna Nuclear Power Plant, LLC 1503 Lake Road Ontario, New York 14519-9364 co ontation *%eoF 585.771.5208 SErnergy 00DF 585.771.3392 Fax April 1, 2013 U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 ATTENTION: Document Control Desk

SUBJECT:

R.E. Ginna Nuclear Power Plant Docket No. 50-244 10 CFR 50.46 Annual ECCS Report

REFERENCE:

(a) Westinghouse Letter LTR-LIS-13-105,

Subject:

10 CFR 50.46 Annual Notification and Reporting for 2012, dated February 28, 2013 In accordance with the requirements in 10 CFR 50.46 paragraph (a)(3)(ii), this annual Emergency Core Cooling System (ECCS) report is hereby submitted by R.E. Ginna Nuclear Power Plant, LLC (Ginna LLC). Westinghouse, the provider of Loss of Coolant Accident (LOCA) analysis services for Ginna LLC, has provided an update to peak cladding temperature (PCT) margin in Reference (a).

Attached please find Enclosure (1), "Westinghouse LOCA Evaluation Model Changes," which is the 2012 annual report of corrections to the Ginna LLC ECCS Evaluation Models. This report summarizes changes made to both the large-break LOCA (LBLOCA) and small-break LOCA (SBLOCA) analyses. The "LBLOCA and SBLOCA Peak Clad Temperature Assessment Sheets" are attached as Enclosure (2).

LAJ O M fLC_.-/ 7

Document Control Desk April 1, 2013 Page 2 Should you have any questions regarding this submittal, please contact Mr. Thomas Harding at (585) 771-5219, or at Thomas. HardingJr@cengllc.com.

Very truly yours, Thomas G. Mo JPO

Enclosures:

(1) Westinghouse LOCA Evaluation Model Changes (2) LBLOCA and SBLOCA Peak Clad Temperature Assessment Sheets cc: W. M. Dean, NRC M. C. Thadani, NRC Resident Inspector, NRC (Ginna LLC)

ENCLOSURE (1)

Westinghouse LOCA Evaluation Model Changes R.E. Ginna Nuclear Power Plant, LLC April 1, 2013

ENCLOSURE (I)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES 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 1999 Westinghouse Best Estimate Large Break LOCA Evaluation Model for Application to PWRs with Upper Plenum Injection 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 of 0°F.

1

ENCLOSURE (1)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES EVALUATION OF FUEL PELLET THERMAL CONDUCTIVITY DEGRADATION AND PEAKING FACTOR BURNDOWN

Background

Fuel pellet thermal conductivity degradation (TCD) and peaking factor burndown were not explicitly considered in the R.E. Ginna Large Break Loss-of-Coolant Accident (LBLOCA) Analysis of Record (AOR). The Nuclear Regulatory Commission (NRC) Information Notice 2011-21 (Reference 1) notified addressees of recent information obtained concerning the impact of irradiation on fuel thermal conductivity and its potential to cause significantly higher predicted peak clad temperature (PCT) in realistic emergency core cooling system (ECCS) evaluation models. This evaluation provides an estimated effect of fuel pellet TCD and peaking factor burndown on the PCT calculation for the ECCS at R.E. Ginna. This change represents a Non-Discretionary Change in accordance with Section 4.1.2 of WCAP-13451 (Reference 2).

Affected Evaluation Model 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect A quantitative evaluation as discussed in Reference 3 was performed to assess the PCT effect of TCD and peaking factor burndown with other considerations of burnup on the R.E. Ginna LBLOCA analysis and concluded that the estimated PCT impact is +230'F for 10 CFR 50.46 reporting purposes. The peaking factor burndown included in the evaluation is provided in Tables 1, 2, and 3. Constellation and its vendor, Westinghouse Electric Company LLC, utilize processes which ensure that the LOCA analysis input values conservatively bound the as-operated plant values for those parameters.

Table 1: FDH Burndown Considered in the Evaluation of TCD Rod Burnup (MWD/MTU) FDH()

0 1.72 30,000 1.72 34,000 1.60 60,000 1.40 62,000 1.40 (1) Includes uncertainties.

(2) Hot assembly average power uses same burndown, since it is a function of FDH.

2

ENCLOSURE (1)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES Table 2: Steady State FQ Burndown Considered in the Evaluation of TCD Rod Burnup FQ Steady-(MWD/MTU) State(')

0 2.0 28,000 2.0 32,000 1.80 60,000 1.45 62,000 1.45 (1) Does not include uncertainties.

Table 3: Transient FQ Burndown Considered in the Evaluation of TCD Rod Burnup (MWD/MTU) FO Transient4 '

0 2.600 28,000 2.600 32,000 2.340 60,000 1.885 62,000 1.885 (1) Indcludes uncertainties.

References

1. NRC Information Notice 2011-21, McGinty, T. J., and Dudes, L. A., "Realistic Emergency Core Cooling System Evaluation Model Effects Resulting From Nuclear Fuel Thermal Conductivity Degradation," December 13, 2011. (NRC ADAMS # ML113430785)

2. WCAP-13451, "Westinghouse Methodology for Implementation of 10 CFR 50.46 Reporting,"

October 1992.

3. LTR-NRC-12-27, Letter from J. A. Gresham (Westinghouse) to NRC, "Westinghouse Input Supporting Licensee Response to NRC 10 CFR 50.54(0 Letter Regarding Nuclear Fuel Thermal Conductivity Degradation (Proprietary/Non-Proprietary)," March 7, 2012.

3

ENCLOSURE (I)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES EVALUATION OF DESIGN INPUT CHANGES

Background

To demonstrate compliance with the 10 CFR 50.46(b)(1) acceptance criterion concerning peak cladding temperature (PCT) when explicitly considering fuel pellet thermal conductivity degradation (TCD) and peaking factor burndown in the R.E. Ginna Large Break Loss-of-Coolant Accident (LBLOCA) analysis, a design input value was revised. This input change is not a change to the approved 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM. The updated input for R.E. Ginna is:

0 Reduction in Steady-State FQ Constellation and its vendor, Westinghouse Electric Company LLC, utilize processes which ensure that the LOCA analysis input values conservatively bound the as-operated plant values for those parameters.

This item represents a change in plant configuration or associated set points, distinguished from an evaluation model change in Section 4 of WCAP-13451 (Reference 2).

Affected Evaluation Model 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect A quantitative evaluation as discussed in Reference I was performed to estimate an overall PCT change due to changes in design input parameters. The evaluation concluded that the estimated PCT impact of the design input change is -96°F for 10 CFR 50.46 reporting purposes.

References

1. LTR-NRC-12-27, Letter from J. A. Gresham (Westinghouse) to NRC, "Westinghouse Input Supporting Licensee Response to NRC 10 CFR 50.54(f) Letter Regarding Nuclear Fuel Thermal Conductivity Degradation (Proprietary/Non-Proprietary)," March 7, 2012.

2. WCAP-13451, "Westinghouse Methodology for Implementation of 10 CFR 50.46 Reporting,"

October 1992.

4

ENCLOSURE (1)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES HOTSPOT BURST TEMPERATURE CALCULATION FOR ZIRLO CLADDING

Background

A problem was identified in the calculation of the burst temperature for ZIRLO1 cladding in the HOTSPOT code when the cladding engineering hoop stress exceeds 15,622 psi. This problem results 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 existing analyses, and its resolution represents a Non-Discretionary Change in accordance with Section 4.1.2 ofWCAP-13451.

Affected Evaluation Model(s) 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 1999 Westinghouse Best Estimate Large Break LOCA Evaluation Model for Application to PWRs with Upper Plenum Injection 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect The evaluation of existing analyses demonstrated no impact on the overall Peak Cladding Temperature (PCT) results, leading to an estimated effect of 0°F.

ZIRLO is a registeredtrademark of Westinghouse Electric Company LLC, its affiliates and/or its subsidiariesin the United States ofAmerica and may be registeredin other countries. All rights reserved. Unauthorizeduse is strictlyprohibited.

5

ENCLOSURE (l)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES HOTSPOT ITERATION ALGORITHM FOR CALCULATING THE INITIAL FUEL PELLET AVERAGE TEMPERATURE

Background

The 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 when the input value satisfies the acceptance criterion; (2) prevent low-end extrapolation of the gap heat transfer coefficient; (3) prevent premature termination of the iteration that occurred under certain conditions; and (4) prevent further adjustment of the gap heat transfer coefficient after reaching the iteration limit. These changes represent a closely-related group of Non-Discretionary Changes in accordance with Section 4.1.2 of WCAP- 13451.

Affected Evaluation Model(s) 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 1999 Westinghouse Best Estimate Large Break LOCA Evaluation Model for Application to PWRs with Upper Plenum Injection 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect Sample calculations and engineering judgment lead to an estimated Peak Cladding Temperature (PCT) impact of 00F.

6

ENCLOSURE (1)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES WCOBRA/TRAC AUTOMATED RESTART PROCESS LOGIC ERROR

Background

A minor error was identified in the WCOBRAiTRAC Automated Restart Process (WARP) logic for defining the Double-Ended Guillotine (DEG) break tables. The error has been evaluated for impact 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- 13451.

Affected Evaluation Model(s) 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 1999 Westinghouse Best Estimate Large Break LOCA Evaluation Model for Application to PWRs with Upper Plenum Injection 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect These errors were evaluated to have a negligible impact on the Large Break LOCA analysis results, leading to an estimated Peak Cladding Temperature (PCT) impact of 00 F.

7

ENCLOSURE (I)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES ROD INTERNAL PRESSURE CALCULATION

Background

Several 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 the uncertainty, 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 issues represents a closely-related group of Non-Discretionary Changes 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 The effects described above are either judged to have a negligible effect on existing LBLOCA analysis results or have been adequately incorporated into the thermal conductivity degradation evaluations, leading to an estimated Peak Cladding Temperature (PCT) impact of 0°F.

8

ENCLOSURE (1)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES MODELING OF THE PELLET CENTER HOLE VOLUME

Background

Various void volumes within the fuel rods are modeled in Large Break Loss-of-Coolant Accident (LOCA) analyses to calculate the rod internal pressure during the Large Break LOCA transient. For fuel rod designs which include annular pellets, one of the volumes modeled is the center hole volume inside the annular pellets. This center hole volume was not modeled in certain Automated Statistical Treatment of Uncertainty Method (ASTRUM) Large Break LOCA analyses. This discrepancy has been evaluated for impact on existing Large Break LOCA analysis results, and its resolution 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 This issue was judged to have a negligible impact on existing Large Break LOCA analysis results, leading to an estimated Peak Cladding Temperature (PCT) impact of 00 F.

9

ENCLOSURE (1)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES WCOBRA/TRAC THERMAL-HYDRAULIC HISTORY FILE DIMENSION USED IN HSDRIVER

Background

A problem was identified in the dimension of the WCOBRA/TRAC thermal-hydraulic history file used in HSDRIVER. The array that is used to store the information from the WCOBRA/TRAC thermal-hydraulic history file is dimensioned to 3000 in HSDRIVER. It is possible for this file to contain more than 3000 curves. If that is the case, it is possible that the curves would not be used 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 a Discretionary Change in accordance with Section 4.1.1 of WCAP-13451.

Affected Evaluation Model(s) 1996 Westinghouse Best Estimate Large Break LOCA Evaluation Model 1999 Westinghouse Best Estimate Large Break LOCA Evaluation Model for Application to PWRs with Upper Plenum Injection 2004 Westinghouse Realistic Large Break LOCA Evaluation Model Using ASTRUM Estimated Effect As discussed in the Background section, resolution of this issue does not impact the PCT calculation for prior LBLOCA analyses, which leads to a PCT impact of 01F.

10

ENCLOSURE (I)

WESTINGHOUSE LOCA EVALUATION MODEL CHANGES NOTRUMP-EM EVALUATION OF FUEL PELLET THERMAL CONDUCTIVITY DEGRADATION

Background

An 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 with analyses using the 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP (NOTRUMP-EM). This change represents a Non-Discretionary Change in accordance with Section 4.1.2 of WCAP- 13451.

Affected Evaluation Model(s) 1985 Westinghouse Small Break LOCA Evaluation Model with NOTRUMP Estimated Effect Based on the phenomena and physics of the SBLOCA transient, in combination with limited sensitivity calculations, it is concluded that TCD has a negligible effect on the limiting cladding temperature transient, leading to an estimated PCT impact of 00 F.

11

ENCLOSURE (2)

LBLOCA and SBLOCA Peak Clad Temperature Assessment Sheets R.E. Ginna Nuclear Power Plant, LLC April 1, 2013

ENCLOSURE (2)

LBLOCA and SBLOCA Peak Clad Temperature Assessment Sheets Westinghouse LOCA Peak Clad Temperature Summary for ASTRUM Best Estimate Large Break Plant Name: R. E. Ginna Utility Name: Constellation Generation Group Revision Date: 2/28/2013 Analysis Information EM: ASTRUM (2004) Analysis Date: 3/18/2005 Limiting Break Size: Split FQ: 2.6 FdH: 1.72 Fuel: 422 Vantage + SGTP (%): 10 Notes: Uprate to 1811 MWt (inclusive of calorimetric uncertainty) Effective beginning Cycle 33, Mixed Core OFA &

422 V+

Clad Temp (IF) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1870 (a)

PCT ASSESSMENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS I . HOTSPOT Fuel Relocation Error 37 2 B. PLANNED PLANT MODIFICATION EVALUATIONS I Evaluation of Design Input Changes -96 3 (b, c) 2 . Evaluation of Elevated Initial Containment and Accumulator Temperature 75 4 (d)

C. 2012 ECCS MODEL ASSESSMENTS I . Evaluation of Pellet Thermal Conductivity Degradation and Peaking Factor 230 3 (b)

Bumdown D. OTHER*

I None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT= 2116

• 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 . RGE-05-32, "Transmittal of Input to Boron Concentration Increase and LOCA Methodology Change Tech Spec Amendment Submittal," April 2005.

2 . LTR-LIS-07-388, "10 CFR 50.46 Reporting Text for HOTSPOT Fuel Relocation Error and Revised PCT Rackup Sheets for R.

E. Ginna," June 2007.

3 . NF-RG-12-45, "Information Regarding the R.E. Ginna Evaluation of Fuel Pellet Thermal Conductivity Degradation and Peaking Factor Burndown Including Analysis Input Changes," July 2012.

4 . LTR-LIS-13-31, "LBLOCA PCT Rackup Sheet Update for the R. E. Ginna Evaluation of Elevated Initial Containment and Accumulator Temperature," January 2013.

Notes:

(a) Transition cycles containing OFA fuel are bounded by the analysis for 422 V+ fuel.

(b) These assessments are coupled via an evaluation of bumup effects which include thermal conductivity degradation, peaking factor burndown., and design input changes. These assessments explicitly include the HOTSPOT Fuel Relocation Error correction.

(c) Design input change was a reduction in steady-state FQ from 2.1 to 2.0.

(d) Note that the LBLOCA analysis-of-record is not impacted by the increase in initial containment temperature. Therefore, the PCT assessment reflects the increase in initial accumulator temperature only.

1

ENCLOSURE (2)

LBLOCA and SBLOCA Peak Clad Temperature Assessment Sheets Westinghouse LOCA Peak Clad Temperature Summary for Appendix K Small Break Plant Name: R. E. Ginna Utility Name: Constellation Generation Group Revision Date: 2/28/2013 Analysis Information EM: NOTRUMP Analysis Date: 4/21/2005 Limiting Break Size: 2 inch, Hi Tavg FQ: 2.6 FdH: 1.72 Fuel: 422 Vantage + SGTP (%): 10 Notes: Uprate to 1811 MWt (inclusive of calorimetric uncertainty), Effective beginning Cycle 33, Mixed Core OFA &

422 V+

Clad Temp (IF) Ref. Notes LICENSING BASIS Analysis-Of-Record PCT 1167 1 (a)

PCT ASSESSMENTS (Delta PCT)

A. PRIOR ECCS MODEL ASSESSMENTS I None 0 B. PLANNED PLANT MODIFICATION EVALUATIONS I . None 0 C. 2012 ECCS MODEL ASSESSMENTS I None 0 D. OTHER*

I None 0 LICENSING BASIS PCT + PCT ASSESSMENTS PCT = 1167

• 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 . RGE-05-32, "Transmittal of Input to Boron Concentration Increase and LOCA Methodology Change Tech Spec Amendment Submittal," April 2005.

Notes:

(a) Transition cycles containing OFA fuel are bounded by the analysis for 422 V+ fuel.

2