ML061280388

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CFR 50.46 30-Day Report for Changes to the Plant Emergency Core Cooling System Performance Analysis
ML061280388
Person / Time
Site: Calvert Cliffs  Constellation icon.png
Issue date: 05/03/2006
From: Spina J
Constellation Energy Group
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML061280388 (10)
v • d • e


Text

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James A. Spina ) Calvert Cliffs Nuclear Power Plant, Inc.

Vice President 1650 Calvert Cliffs Parkway Lusby, Maryland 20657 410.495.4455 410.495.3500 Fax Constellation Energy Generation Group May 3, 2006 U. S. Nuclear Regulatory Commission Washington, DC 20555 ATTENTION: Document Control Desk

SUBJECT:

Calvert Cliffs Nuclear Power Plant UnitNos. 1 & 2; DocketNos. 50-317 & 50-318 10 CFR 50.46 30-Day Report for Changes to the Calvert Cliffs Nuclear Power Plant Emergency Core Cooling Svstem Performance Analysis This letter is submitted pursuant to 10 CFR 5O.46( )(3)(ii) to provide notification of a significant change to the peak cladding temperature of the large brea loss-of-coolant accident (LBLOCA) and small break loss-of-coolant accident (SBLOCA) analyses for Calvert Cliffs Nuclear Power Plant (CCNPP).

The analyses for the LBLOCA and SBLOCA Emergency Core Cooling System performance have been re-analyzed for the upcoming Unit 1 cycle (Cycle 18). The re-analyses were performed using the latest Nuclear Regulatory Commission (NRC)-acceptediversions of the Westinghouse evaluation models for Combustion Engineering designed pressurized water reactors (References a and b). The new analyses explicitly model the new fuel rod design being introduced in Cycle 18. The new fuel rod design implements ZIRLO"m clad Zirconium Diboride Integral Fuel Burnable Absorber (ZrB 2 IFBA) and U0 2 fuel rods with axial blankets and annular pellets into previously analyzed and implemented mixing vane grids.

Calvert Cliffs Nuclear Power Plant requeste an enment to the CCNPP Unit 1 and Unit 2 operating license (Reference c) to add the methodolo,'j ref rxe for the implementation of ZrB2 LFBA coatings in CE Nuclear Power fuel assembly designs Revernce d) to the list of approved core operating limits analytical methods in the Technical Specifications. The NRC approved this request on February 24, 2005 (Reference e).

The results of the new analyses and their mpliance with 10 CFR 50.46 are summarized in Attachment (1). As described in the attachmenthe new LBLOCA and SBLOCA analyses constitute new licensing basis analyses (analyses-ot-record) for Unit 1. A description of the analyses will be incorporated into a future revision of the CCl PMJped Final Safety Analysis Report.

The results of the new LBLOCA and SBLOCA antlyses conform to the Emergency Core Cooling System acceptance criteria of 10 CFR 50.46(b). Becausethe sum of the absolute magnitudes of the effects on peak cladding temperature due to the changes is greater than 50°, the changes qualify as being significant as defined in 10 CFR 50.46(a)(3)(i). The changes to the fuel rod design have already been analyzed for Unit 2 (Reference f). Reference (f) stated that a separate 30-day report for Unit 1 would not

Document Control Desk May 3, 2006 Page 2 be submitted unless there were changes that caused the Unit 1 results or methods to be different. A modeling error (details to be provided as part of the annual Entrgency Core Cooling System report) caused the Unit 1 results to differ from those reported in Reference (f), resulting in this separate 30-day report submittal. Consequently, the Vnit 1 changes are being submitted in this 30-day report. The new analyses are the licensing basis analyses for Unit 1 upon startup of Cycle 18 and were implemented on April 6, 2006 when Unit 1 entered Mode 4.

Should you have questions regarding this matter, please contact Mr. L. S. Larragoite at (410) 495-4922.

Very truly.yours, JAS/PSF/bjd

Attachment:

(1) 10 CFR 50.46 30-Day Report for Changes to the Calvert Cliffs Nuclear Power Plant Emergency Core Cooling System Performance Analysis

REFERENCES:

(a) CENPD-132, Supplement 4-P-A, "Calculative Methods for the CE Nuclear Power Large Break LOCA Evaluation Model," March 2001 (b) CENPD-137, Supplement 2-P-A, "Calculative Methods for the ABB CE Small Break LOCA Evaluation Model," April 1998 (c) Letter from Mr. B. S. Montgomery (CCNPP) to Document Control Desk (NRC), dated July 15, 2004, "License Amendment Request: Incorporate Methodology References for the Implementation of PHOENIX-P, ANC, PARAGON, and Zirconium Diboride into the Technical Specifications" (d) WCAP-16072-P-A, Rev. 0, "Implementation of Zirconium Diboride Burnable Absorber Coatings in CE Nuclear Power Fuel Assembly Designs," August 2004.

(e) Letter from Mr. R. V. Guzman (NRC) to Mr. G. Vanderheyden (CCNPP), dated February 24, 2005, "Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 - Amendment Re: Incorporating Core Operating Limits Analytical Methodology References into Technical Specifications (TAC Nos. MC4019 and MC4020)"

(f) Letter from Mr. G. Vanderheyden to Document Control Desk (NRC), dated April 6, 2005, "Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 & 2; Docket Nos. 50-317 & 50-318, 10 CFR 50.46 30-Day Report for Changes to the Calvert Cliffs Nuclear Power Plant Emergency Core Cooling System Performance Analysis" cc: P. D. Milano, NRC Resident Inspector, NRC S. J. Collins, NRC R. I. McLean, DNR

ATTACHMENT (1) 10 CFR 50.46 30-DAY REPORT FOR CHANGES TO THE CALVERT CLIFFS NUCLEAR POWER PLANT EMERGENCY CORE COOLING SYSTEM PERFORMANCE ANALYSIS Calvert Cliffs Nuclear Power Plant, Inc.

May 3, 2006

ATTACHMENT (1) 10 CER 50.46 30-DAY REPORT FOR CHANGES TO THE CALVERT CLIFFS NUCLEAR POWER PLANT EMERGENCY CORE COOLING SYSTEM PERFORMANCE ANALYSIS INTRODUCTION This 30-day report is provided for the Calvert Cliffs Nuclear Power Plant (CCNPP) in accordance with the requirements of 10 CFR 50.46(a)(3Xii) for reporting (1) changes in an acceptable evaluation model or the application of such a model, and (2) the estimated effect of the changes on the limiting Emergency Core Cooling System (ECCS) analysis. Because the effect on the peak cladding temperature (PCT) of the changes described herein is greater than 50'F, the changes qualify as significant as defined in 10 CFR 50.46(a)(3)(i) and, consequently, are provided in this 30-day report.

Emergency Core Cooling System performance for both the large break loss-of-coolant accident (LBLOCA) and the small break loss-of-coolant accident (SBLOCA) has been re-analyzed for CCNPP Unit 1. The analyses were performed with the latest Nuclear Regulatory Commission (NRC)-accepted versions of the Westinghouse Appendix K evaluation models for Combustion Engineering designed pressurized water reactors (PWRs). The analyses explicitly modeled the new fuel rod design that is being introduced in Cycle 18. The new fuel rod design implements ZIRLOTm clad Zirconium Diboride Integral Fuel Burnable Absorber (ZrB2 IFBA) and U0 2 fuel rods with axial blankets and annular pellets into previously analyzed and implemented mixing vane grids.

The new LBLOCA and SBLOCA analyses are not assessments (i.e., they do not provide an estimate of the effect of the changes on the limiting ECCS analysis). Rather, they are complete re-analyses that use acceptable evaluation models that are applicable to CCNPP Unit 1. A summary description of the new analyses and their compliance with 10 CFR 50.46 is provided below.

LBLOCA ECCS PERFORMANCE ANALYSIS LBLOCA Evaluation Model The new LBLOCA ECCS performance analysis was performed with the 1999 Evaluation Model (EM) version of the Westinghouse LBLOCA evaluation model for Combustion Engineering designed PWRs (Reference 1). Additionally, the analysis used the ZIRLO'm cladding models described in Reference 2 and the models and processes for analyzing ZrB2 IFBA fuel rods described in Reference 3. The 1999 EM, the ZIRLOr cladding, and the ZrB2 IFBA topical reports were generically accepted by the NRC in References 4, 5, and 6 for licensing applications for Combustion Engineering designed PWRs.

The 1999 EM, the ZIRLOTh cladding, and the ZrB2 IFBA topical reports are listed in Technical Specification 5.6.5.b of the CCNPP Technical Specifications as approved analytical methodologies that can be used to determine core operating limits in the Core Operating Limits Report. The license amendment requests to add these methodologies to the Technical Specifications, were submitted to the NRC in References 7 and 8 and were accepted by the NRC in References 9 and 10.

The analysis complies with the limitations/constraints imposed by the Safety Evaluation Reports (SERs) for the 1999 EM, the ZIRLOT cladding, and the ZrB2 IFBA topical reports as well as the applicable limitations/constraints imposed by the SERs for earlier versions of the LBLOCA evaluation model.

Fuel Desien Changes The Batch X fuel assemblies introduced in Unit 1 Cycle 18 use mixing vane grids (Turbo fuel assembly),

ZIRLOQ m cladding, ZrB IFBA coated U0 fuel pellets, and fuel rods with low enriched axial blankets 2 2 and annular pellets. The new LBLOCA analysis explicitly analyzed the various fuel designs present in Unit 1 Cycle 18 in order to ensure that limiting fuel rod conditions were selected for the break spectrum I

ATTACHMENT (1) 10 CFR 50.46 30-iDAY REPORT-FOR CHANGES TO THE CALVERT CLIFFS NUCLEAR POWER PLANT EMERGENCY CORE COOLING SYSTEM PERFORMANCE ANALYSIS analysis. The hot rod heatup portion Of the break spectrum analysis, which is performed with the STRIKIN-il computer code, analyzed a;ZIRLO'clad UOQ rod in a Turbo fuel assembly. It used reflood heat transfer coefficients that were conservatively biased in order to bound the results of the more limiting fuel types present in Unit 1 Cycle 18, which will not be present in future cycles.

Other Plant Parameter Changes In addition to the changes described above, the new LBLOCA analysis introduced several other changes to plant parameters used in the analysis. There was an increase in the Peak Linear Heat Generation Rate from 14.3 kW/ft to 14,5 kW/ft. Also, the Unit 1 Cycle 18 plant parameters included a 33 f/tank reduction in the safety injection tank (SIT) minimum water volume and a 20 psig reduction in the minimum SIT pressure. Each of these changes lead to more limiting ECCS performance analysis results to bound as-operated performance.

The new LBLOCA analysis also incorporated new bounding values for several physics parameters in order to bound future cycle-to-cycle variations in the values of the parameters.

Results and Conclusion of the New LBLOCA Analysis Table 1 compares important inputs used in the current and the new LBLOCA analyses. Table 2 compares important results from the two anilyses. A more detailed description of the new analysis, including tables and figures that present the results of the break spectrum analysis, will be incorporated into a future revision of the CCNPP Updated Final Safety Analysis Report.

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ATTACHMENT (1) 10 CFR 50.46 30-DAY REPORT FOR CHANGES TO THE CALVERT CLIFFS NUCLEAR POWER PLANT EMERGENCY CORE COOLING SYSTEM PERFORMANCE ANALYSIS Table I Comparison of Important Parameters Used in the Current and New CCNPP Unit I LBLOCA ECCS Performance Analysis Parameter Current Analysis New Analysis LBLOCA Evaluation Model 1999 EM 1999 EM Core Power Level, MWt (including power measurement 2754 2754 uncertainty) 2754_2754 Peak Linear Heat Generation Rate, kW/ft 14.3 14.5 Hot Rod Pin-to-Box Factor 1.025 1.025 RCS Flow Rate, gpm 370,000 370,000 RCS Pressure, psia 2250 2250 Cold Leg Temperature, OF 546 546 Hot Leg Temperature, OF 597 597 Steam Generator Tube Plugging, plugged tubes/SG 847 847 Fuel Pin Integral Burnable Absorber Design absorber ZrB2 coating wath Fuel Bundle Design Turbo mixing Turbo mixing vanes vanes Fuel Cladding ZIRLOTm ZIRLOTM Table 2 Comparison of Important Results of the Current and New CCNPP Unit I LBLOCA ECCS Performance Analysis Parameter Current Analysis New Analysis Limiting Break Size 0.6 DEG/PD( 8) 0.6 DEG/PD Peak Cladding Temperature, 0F 2026 2057 Time of Peak Cladding Temperature, sec 269 252 Maximum Cladding Oxidation, % 8.58 9.95 Maximum Core-Wide Cladding Oxidation, % <0.99 <0.99 Time of Cladding Rupture, sec 26.1 27.5 (a) DEG/PD = Double-Ended Guillotine Break in Pump Discharge Leg As summarized below, the results of the new LBLOCA analysis conform to the acceptance criteria of 10 CFR 50.46(b).

Pirameter Criterion Result Peak Cladding Temperature, IF

  • 2200 2057 Maximum Cladding Oxidation, % *17 9.95 Maximum Core-Wide Oxidation, % *1 <0.99 Coolable Geometry Yes Yes 3

ATTACHMENT (1) 10 CFR 50.46 30-DAY REPORT FOR CHANGES TO THE CALVERT CLIFFS NUCLEAR POWER PLANT EMERGENCY CORE COOLING SYSTEM PERFORMANCE ANALYSIS The new LBLOCA analysis uses the 1999 EM, which is approved by the NRC for licensing applications for Combustion Engineering designed PWRs such as CCNPP. The analysis complies with the limitations/constraints imposed by all applicable SERs. The analysis uses values for plant design data that are either applicable to or bound the configuration of Unit 1 Cycle 18. Calvert Cliffs Nuclear Power Plant, Inc. and Westinghouse have ongoing processes that ensure that the as-operated plant values for PCT-sensitive parameters remain bounded by the values used in the analysis.

SBLOCA ECCS PERFORMANCE ANALYSIS SBLOCA EM The new SBLOCA ECCS performance analysis was performed with the S2M (Supplement 2 to CENPD-137 Evaluation Model) version of the Westinghouse SBLOCA evaluation model for Combustion Engineering designed PWRs (Reference 11). Additionally, the analysis used the ZIRLOT m cladding models described in Reference 2 and the models and processes for analyzing ZrB2 IFBA fuel rods described in Reference 3. The S2M, the ZIRLOTm cladding, and the ZrB 2 IFBA topical reports were generically accepted by the NRC in References 5, 6, and 12 for licensing applications for Combustion Engineering designed PWRs.

The S2M, the ZIRLO'r cladding, and the ZrB2 IFBA topical reports are listed in Technical Specification 5.6.5.b of the CCNPP Technical Specifications as approved analytical methodologies that can be used to determine core operating limits in the Core Operating Limits Report. The license amendment requests to add these methodologies to the Technical Specifications were submitted to the NRC in References 7 and 8 and were accepted by the NRC in References 9 and 10.

The analysis complies with the limitations/constraints imposed by the SERs for the K2M, the ZIRLOTm cladding, and the ZrB2 IFBA topical reports as well as the applicable limitations/constraints imposed by the SERs for earlier versions of the SBLOCA EM.

Fuel Desien Changes The new SBLOCA analysis used limiting initial fuel rod conditions that bound the various fuel and cladding types present in Cycle 18, including ZIRLOTmclad ZrB 2 IFBA coated U0 2 fuel pellets, and fuel rods with low enriched axial blankets and annular pellets.

Other Plant Parameter Changes In addition to the changes described above, the new SBLOCA analysis introduced several other changes to plant parameters used in the analysis. The changes include the following:

  • Change in the Peak Linear Heat Generation Rate to 15.0 kW/ft
  • 33 fO/tank reduction in the SIT minimum water volume and a 20 psig reduction in the minimum SIT pressure Results and Conclusion of the New SBLOCA Analysis Tables 3 and 4 compare important inputs and results from the new SBLOCA analysis to those of the current SBLOCA analysis. A more detailed description of the new analysis, including tables and figures 4

i ATTACHMENT (1) 10 CFR 50.46 30-DAY REPORT FOR CHANGES TO THE CALVERT CLIFFS NUCLEAR POWER PLANT EMERGENCY CORE COOLING SYSTEM PERFORMANCE ANALYSIS that present the results of the break spectrum analysis, will be incorporated into a future revision of the CCNPP Updated Final Safety Analysis Report.

Table 3 Comparison of Important Parameters Used In the Current, Reference 13, and New CCNPP Unit I SBLOCA ECCS Performance Analysis Parameter Current Analysis Reference 13 and SBLOCA Evaluation Model S2M S2M Core Power Level, MWt (including power measurement 2754 2754 uncertainty)

Peak Linear Heat Generation Rate, kW/ft 14.3 15.0 RCS Flow Rate, gpm 370,000 370,000 RCS Pressure, psia 2250 2250 Cold Leg Temperature, 'F 550 550 Hot Leg Temperature, OF 601 601 Steam Generator Tube Plugging, plugged tubes/SG 847 847 Fuel Pin Integral Bumable Absorber Design Erbia burnable ZrB 2 coating with absorber axial blankets Fuel Bundle Design Turbo mixing vanes Turbo mixing vanes Fuel Cladding ZIRLO~m ZIRLOTM Table 4 Comparison of Important Results of the Current, Reference 13, and New CCNPP Unit I SBLOCA ECCS Performance Analysis Parameter Current Analysis l eAnalysis l New Analysis Limiting Break Size(a) 0.08 ft2 /PD(b) 0.08 ft2 /PD 0.08 ft2/PD Peak Cladding Temperature, OF 1955 1815 1855 Time of Peak Cladding Temperature, sec 1293 1311 1292 Maximum Cladding Oxidation, % 9.03(c) 5.70 7.20 Maximum Core-Wide Cladding Oxidation, % <0.81 <0.60 <0.60 Time of Cladding Rupture, sec 1125 1309 1290 (a) Break that resulted in the highest peak cladding temperature.

(b) PD = Pump Discharge Leg (c) The 0.06 ft2 /PD break produced the maximum cladding oxidation.

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ATTACHMENT (1) 10 CFR 50.46 30-DAY REPORT FOR CHANGES TO THE CALVERT CLIFFS NUCLEAR POWER PLANT EMERGENCY CORE COOLING SYSTEM PERFORMANCE ANALYSIS As summarized below, the results of the new SBLOCA analysis conform to the acceptance criteria of 10 CFR 50.46(b).

Parameter Criterion Result Peak Cladding Temperature, 'F *2200 1855 Maximum Cladding Oxidation, % *17 7.20 Maximum Core-Wide Oxidation, % s 1 <0.60 Coolable Geometry Yes Yes The new SBLOCA analysis uses the S2M, which is accepted by the NRC for, licensing applications for Combustion Engineering designed PWRs such as CCNPP. The analysis complies with the limitations/constraints imposed by all applicable SERs. The analysis uses values for plant design data that are either applicable to or bound the configuration of Unit I Cycle 18. Calvert Cliffs Nuclear Power Plant, Inc. and Westinghouse have ongoing processes that ensure that the as-operated plant values for PCT-sensitive parameters remain bounded by the values used in the analysis.

Apnlicabilitv of the New Analyses to Unit 2 The new LBLOCA and SBLOCA analyses were performed to be applicable to both Unit 1 and Unit 2 after the installation of the new fuel rod design. The new fuel rod design has already been installed in Unit 2 during the 2005 refueling outage (Reference 13). A modeling error (details to be provided as part of the annual ECCS report) caused the SBLOCA results previously reported in Reference 13 to change to those reported in this 30-day ECCS report for both Units 1 and 2.

Summary The new LBLOCA and SBLOCA analyses comply with 10 CFR 50.46 as follows:

  • The analyses were performed with acceptable evaluation models and included sensitivity studies that assured the limiting LBLOCA and SBLOCA were analyzed [10 CFR 50.46(aXl)(i)].
  • The results of the new LBLOCA and SBLOCA analyses conform to the ECCS acceptance criteria

[10 CFR 50.46(b)].

  • This 30-day report provides NRC with notification of the change in the application of the evaluation models and their effect on the limiting ECCS analyses [10 CFR 50.46(a)(3)(ii)].

The new LBLOCA and SBLOCA analyses constitute new licensing basis analyses (analyses-of-record).

They will be used as the reference analyses to evaluate the impact on PCT of future changes to or errors in the 1999 EM and the S2M, and their application to CCNPP.

REFERENCES

1. CENPD-132, Supplement 4-P-A, "Calculative Methods for the CE Nuclear Power Large Break LOCA Evaluation Model," March 2001
2. CENPD-404-P-A, Revision 0, "Implementation of ZIRLOm Cladding Material in CE Nuclear Power Fuel Assembly Designs," November 2001
3. WCAP-16072-P-A, Rev. 0, "Implementation of Zirconium Diboride Burnable Absorber Coatings in CE Nuclear Power Fuel Assembly Designs," August 2004 6

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ATTACHMENT (1) 10 CFR 50.46 30-DAY REPORT FOR C4AIGES TO THE CALVERT CLIFFS NUCLEAR POWER PLANT EMERGENCY CORE COOLING SYSTEM PERFORMANCE ANALYSIS

4. Letter from Mr. S. A. Richards (NRC) to Mr. P. W. Richardson (Westinghouse), dated December 15, 2000, "Safety Evaluation of Topical Report CENPD-132, Supplement 4, Revision 1, 'Calculative Methods for the CE Nuclear Power Large Break LOCA Evaluation Model' (TAC No. MA5660)"
5. Letter from Mr. S. A. Richards (NRC) to Mr. P. W. Richardson (Westinghouse), dated September 12, 2001, "Safety Evaluation of Topical Report; CENPD-404-P, Revision 0,

'Implementation of ZIRLO Material Cladding in CE Nuclear Power Fuel Assembly Designs' (TAC No. MB1035)"

6. Letter from Mr. H. N. Berkow (NRC) to Mr. J. A. Gresham (Westinghouse), dated May 6, 2004, "Final Safety Evaluation for Topical Report WCAP-16072-P, Revision 00, 'Implementation of Zirconium Diboride Burnable Absorber Coatings in CE Nuclear Power Fuel Assembly Designs,'

(TAC No. MB8721)"

7. Letter from Mr. C. H. Cruse (CCNPP) to Document Control Desk (NRC), dated July 27, 2001, "License Amendment Request: Incorporate Methodology References for the Implementation of ZIRLO Clad Fuel Rods into the Technical Specifications"
8. Letter from Mr. B. S. Montgomery (CCNPP) to Document Control Desk (NRC), dated July 15, 2004, "License Amendment Request: Incorporate Methodology References for the Implementation of PHOENIX-P, ANC, PARAGON, and Zirconium Diboride into the Technical Specifications"
9. Letter from Ms. D. Skay (NRC) to Mr. C. H. Cruse (CCNPP), dated April 8, 2002, "Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 and 2 Amendment Re: Implementation of ZIRLO Clad Fuel Rods (TAC Nos. MB2540 and MB2541)"
10. Letter from Mr. R. V. Guzman (NRC) to Mr. G. Vanderheyden (CCNPP), dated February 24, 2005, "Calvert Cliffs Nuclear Power Plant, Unit Nos. I and 2 - Amendment Re: Incorporating Core Operating Limits Analytical Methodology References into Technical Specifications (TAC Nos. MC4019 and MC4020)"
11. CENPD-137, Supplement 2-P-A, "Calculative Methods for the ABB CE Small Break LOCA Evaluation Model," April 1998
12. Letter from Mr. T. H. Essig (NRC) to Mr. I. C. Rickard (ABB Combustion Engineering), dated December 16, 1997, "Acceptance' for Referencing of the Topical Report CENPD-137(P),

Supplement 2, 'Calculative Methods for the C-E Small Break LOCA Evaluation Model' (TAC No. M95687)"

13. Letter from Mr. G. Vanderheyden to Document Control Desk (NRC), dated April 6, 2005, "Calvert Cliffs Nuclear Power Plant, Unit Nos. 1 & 2; Docket Nos. 50-317 & 50-318, 10 CFR 50.46 30-Day Report for Changes to the Calvert Cliffs Nuclear Power Plant Emergency Core Cooling System Performance Analysis" 7
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