ML021340611
| ML021340611 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 05/03/2002 |
| From: | Mauldin D Arizona Public Service Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| 102-04699-CDM/TNw/JAP | |
| Download: ML021340611 (12) | |
Text
10 CFR 50.46 David Mauldin Vice President Mail Station 7605 Palo Verde Nuclear Nuclear Engineering TEL (623) 393-5553 P.O. Box 52034 Generating Station and Support FAX (623) 393-6077 Phoenix, AZ 85072-2034 102-04699-CDM/TNW/JAP May 3, 2002 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Mail Station P1-37 Washington, DC 20555-0001
References:
- 1.
CENPD-132, Supplement 4-P-A, "Calculative Methods for the CE Nuclear Power Large Break LOCA Evaluation Model," March 2001.
- 2.
CENPD-1 37, Supplement 2-P-A, "Calculative Methods for the ABB CE Small Break LOCA Evaluation Model," April 1998.
- 3.
Letter 102-04641-CDM/RAB, dated December 21, 2001, "PVNGS Unit 2 - Request for a License Amendment to Support Replacement of Steam Generators and Uprated Power Operations," from David Mauldin, APS to USNRC
- 4.
CENPD-404-P-A, Revision 0, "Implementation of ZIRLOT M Cladding Material in CE Nuclear Power Fuel Assembly Designs,"
November 2001.
- 5.
Letter 102-04623-CDM/TNW/JAP, dated November 9, 2001, "Request for Amendment to Technical Specification 5.6.5b, Core Operating Limits Report (COLR)," from David Mauldin, APS to USNRC
- 6.
Letter dated March 12, 2002, Jack Donohew (USNRC) to G. R.
Overbeck (Arizona Public Service Company), "PVNGS, Units 1, 2, and 3 - Issuance of Amendments RE: Technical Specification 5.6.5b, Core Operating Limits Report (COLR) and use of ZIRLO Cladding Material, (TAC Nos. MB3373, MB3374, and MB3375)"
Dear Sirs:
Subject:
Palo Verde Nuclear Generating Station (PVNGS)
Units 1, 2, and 3 Docket Nos. STN 50-528/5291530 10 CFR 50.46(a)(3)(ii) 30-Day Report for Changes in LOCANECCS Performance Evaluation Models
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 10 CFR 50.46(a)(3)(ii) 30-Day Report for Changes in LOCA/ECCS Performance Evaluation Models Page 2 Pursuant to 10 CFR 50.46(a)(3)(ii), this letter provides notification of a change to the Peak Cladding Temperature (PCT) of the Large Break Loss-of-Coolant Accident (LBLOCA) and Small Break Loss-of-Coolant Accident (SBLOCA) analyses for Palo Verde Nuclear Generating Station (PVNGS) Units 1, 2 and 3. The PCT changes are not due to any errors, rather, they are derived mostly from a changeover to new Nuclear Regulatory Commission (NRC) accepted 10 CFR 50, Appendix K evaluation models.
LBLOCA and SBLOCA Emergency Core Cooling System (ECCS) performance has been reanalyzed for the upcoming operating cycle (Cycle 11) of PVNGS Unit 2. These analyses are also bounding for PVNGS Units 1 and 3. The reanalyses were performed using the latest NRC accepted versions of the Westinghouse 10 CFR 50, Appendix K evaluation models for Combustion Engineering designed nuclear steam supply systems (NSSSs) (References 1 and 2). The analyses explicitly model the new ZIRLOTM clad fuel design that is being introduced in PVNGS-2, Cycle 11.
In addition, these analyses not only apply to PVNGS Units 1, 2 & 3 at their current licensed power level of 3876 megawatts thermal, but will also apply to the 3990 megawatts thermal power level for the PVNGS Unit 2 anticipated power uprate (Reference 3).
Arizona Public Service requested an amendment to the PVNGS Units 1, 2, and 3 operating licenses to add the methodology reference for ZIRLOTM cladding (Reference
- 4) to the list of approved core operating limits analytical methods in the Technical Specifications (Reference 5). The NRC issued the license amendment on March 12, 2002 (Reference 6).
The Enclosure to this letter summarizes the results of the new analyses and their compliance with 10 CFR 50.46. As described in the Enclosure, the new LBLOCA and SBLOCA analyses constitute new licensing basis analyses (Analyses-Of-Record) for Units 1, 2, and 3. A complete description of the analyses will be incorporated into the PVNGS Updated Final Safety Analysis Report in accordance with the requirements of 10 CFR 50.71 (e).
The results of the new LBLOCA and SBLOCA analyses conform to the ECCS acceptance criteria of 10 CFR 50.46(b). However, because the sum of the absolute magnitudes of the effects on PCT due to the change in evaluation models is greater than 50 OF, the implementation of new evaluation models constitute a report condition as defined in 10 CFR 50.46(a)(3)(ii).
U.S. Nuclear Regulatory Commission ATTN: Document Control Desk 10 CFR 50.46(a)(3)(ii) 30-Day Report for Changes in LOCA/ECCS Performance Evaluation Models Page 3 No commitments are being made to the NRC by this letter.
If you have any questions, please contact Thomas N. Weber at (623) 393-5764.
Sincerely, CDM/TNW/JAP cc:
E. W. Merschoff J. N. Donohew J. H. Moorman
ENCLOSURE 10 CFR 50.46 Thirty-Day Report for Changes to Palo Verde Nuclear Generating Station Units 1, 2, and 3 ECCS Performance Analysis
10 CFR 50.46 Thirty-Day Report for Changes to Palo Verde Nuclear Generating Station Units 1, 2, and 3 ECCS Performance Analysis Introduction This 30-day report is provided for Palo Verde Nuclear Generating Station (PVNGS)
Units 1, 2, and 3 in accordance with the requirements of 10 CFR 50.46(a)(3)(ii) 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 ECCS analysis.
Because the effect on the Peak Cladding Temperature (PCT) of the changes described herein is greater than 50 OF, the changes constitute a reportable condition as defined in 10 CFR 50.46(a)(3)(i) and, consequently, are provided in this 30-day report. The PCT changes are not due to any errors, rather, they are derived mostly from a changeover to new Nuclear Regulatory Commission (NRC) accepted 10 CFR 50, Appendix K evaluation models.
Emergency Core Cooling System (ECCS) performance for both the Large Break Loss of-Coolant Accident (LBLOCA) and the Small Break Loss-of-Coolant Accident (SBLOCA) have been re-analyzed for the upcoming PVNGS Unit 2, Cycle 11. These analyses were performed to also bound the conditions for PVNGS Units 1 and 3. The analyses were performed with the latest NRC accepted versions of the Westinghouse 10 CFR 50, Appendix K evaluation models for Combustion Engineering designed nuclear steam supply systems (NSSSs). In addition, the analyses explicitly model the new ZIRLOTM clad fuel design that is being introduced in PVNGS-2, Cycle 11.
The new LBLOCA and SBLOCA analyses are complete re-analyses performed using acceptable evaluation models that are applicable to PVNGS Units 1, 2, and 3. A summary description of the new analyses and their compliance with 10 CFR 50.46 are provided below.
LBLOCA ECCS Performance Analysis LBLOCA Evaluation Model (EM)
The new LBLOCA ECOS performance analysis was performed with the 1999 EM version of the Westinghouse LBLOCA evaluation model for Combustion Engineering designed NSSSs (Reference 1). Additionally, the analysis used the ZIRLOTM cladding models described in Reference 2. The 1999 EM and ZIRLOTM cladding topical reports were generically accepted by the NRC for licensing applications in References 3 and 4.
The ZIRLO TM cladding topical report is listed in Technical Specification 5.6.5b of the PVNGS Units 1, 2 and 3 Technical Specifications as an approved analytical methodology that can be used to determine core operating limits in the Core Operating Limits Report (COLR). The license amendment request to add this methodology to the 1
Technical Specifications was submitted to the NRC in Reference 5 and was accepted by the NRC in Reference 6.
The 1999 EM version of the Westinghouse LBLOCA evaluation model has been updated in the PVNGS cycle specific COLR as this new ECCS Analysis of Record has been implemented (April 10, 2002).
The LBLOCA analysis complies with the limitations and constraints imposed by the Safety Evaluations (SEs) for the 1999 EM and ZIRLOTM cladding topical reports as well as the limitations and constraints imposed by the SEs for earlier versions of the LBLOCA evaluation model for those aspects that continue to remain applicable.
The previous PVNGS Units 1, 2 and 3 LBLOCA analysis used the 1985 EM version of the Westinghouse LBLOCA evaluation model for Combustion Engineering designed NSSSs (Reference 7).
Fuel Design Changes The Batch N fuel assemblies being introduced in PVNGS-2, Cycle 11 use ZIRLO TM cladding. The new LBLOCA analysis explicitly analyzed the various fuel designs present in Cycle 11 (i.e., Zircaloy and ZIRLOTM with Erbia and U02) in order to ensure that limiting fuel rod conditions were selected for the break spectrum analysis. The conditions also bound the fuel types present in PVNGS Units 1 and 3.
Other Plant Parameter Changes In addition to the changes described above, the new LBLOCA analysis introduced several other changes to plant specific parameters used in the analysis. The most notable change was incorporating updated containment heat sink data. The updated heat sink data is more conservative than the data used in earlier analyses.
Results and Conclusion of the New LBLOCA Analysis Table 1 compares important inputs used in the previous and the new LBLOCA analyses. The new analysis uses values for plant design data that are either applicable to or bound the configuration of Units 1, 2 and 3 including Unit 2 Cycle 11. Table 2 compares important results from the two analyses. 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 the PVNGS Units 1, 2 and 3 Updated Final Safety Analysis Report in accordance with the requirements of 10 CFR 50.71 (e).
As summarized below, the results of the new LBLOCA analysis conform to the acceptance criteria of 10 CFR 50.46(b).
2
Parameter Peak Cladding Temperature
_< 2200 OF 2110 OF Maximum Cladding Oxidation
_< 17%
12%
Maximum Core-Wide Oxidation
< 1%
< 0.99%
Coolable Geometry Yes Yes SBLOCA ECCS Performance Analysis SBLOCA Evaluation Model 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 NSSSs (Reference 8). Additionally, the analysis used the ZIRLOTM cladding models described in Reference 2. The S2M and ZIRLOTM cladding topical reports were generically accepted by the NRC for licensing applications in References 9 and 4.
The ZIRLOTM cladding topical report is listed in Technical Specification 5.6.5b of the PVNGS Units 1, 2 and 3 Technical Specifications as an approved analytical methodology that can be used to determine core operating limits in the Core Operating Limits Report (COLR). The license amendment request to add this methodology to the Technical Specifications was submitted to the NRC in Reference 5 and was accepted by the NRC in Reference 6.
The S2M version of the Westinghouse SBLOCA evaluation model has been updated in the PVNGS cycle specific COLR as this new ECCS Analysis of Record has been implemented (April 10, 2002).
The analysis complies with the limitations and constraints imposed by the SEs for the S2M and the ZIRLOTM cladding topical reports as well as the limitations and constraints imposed by the SEs for earlier versions of the SBLOCA evaluation model for those aspects that continue to remain applicable.
The previous PVNGS Units 1, 2 and 3 SBLOCA analysis used the S1 M (Supplement 1 to CENPD-137 Evaluation Model) version of the Westinghouse SBLOCA evaluation model for Combustion Engineering designed NSSSs (Reference 10).
Fuel Design Changes The Batch N fuel assemblies being introduced in PVNGS-2, Cycle 11 use ZIRLO TM cladding. The new SBLOCA analysis explicitly analyzed the various fuel designs present in Cycle 11 (i.e., Zircaloy and ZIRLO TM with Erbia and U02) in order to ensure that limiting fuel rod conditions were selected for the break spectrum analysis. The conditions also bound the fuel types present in PVNGS Units 1 and 3.
3 Criterion Result
Other Plant Parameter Changes In addition to the changes described above, the new SBLOCA analysis introduced several other minor changes to plant specific parameters used in the analysis.
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 previous SBLOCA analysis. The analysis uses values for plant design data that are either applicable to or bound the configuration of Units 1, 2 and 3 including Unit 2 Cycle 11. A more detailed description of the new analysis, including tables and figures that show the results of the break spectrum analysis, will be incorporated into the PVNGS Updated Final Safety Analysis Report in accordance with the requirements of 10 CFR 50.71 (e).
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
<2200 OF 1618 OF Maximum Cladding Oxidation
< 17%
1.28%
Maximum Core-Wide Oxidation
< 1%
< 0.2%
Coolable Geometry Yes Yes Summary The new LBLOCA and SBLOCA analyses comply with 10 CFR 50.46 as follows:
- 1. The analyses were performed with evaluation models approved by the Nuclear Regulatory Commission and included sensitivity studies that assured the limiting LBLOCA and SBLOCA were analyzed (10 CFR 50.46(a)(1)(i)).
- 2. The results of the new LBLOCA and SBLOCA analyses conform to the ECCS acceptance criteria (10 CFR 50.46(b)).
- 3. 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 analyses explicitly model the new ZIRLOTM clad fuel design that is being introduced in PVNGS-2, Cycle 11.
4
In addition, these analyses not only apply to PVNGS Units 1, 2 & 3 at their current licensed power level of 3876 megawatts thermal, but will also apply to the 3990 megawatts thermal power level for the PVNGS Unit 2 anticipated power uprate (Reference 11).
The new LBLOCA and SBLOCA analyses constitute new licensing basis analyses (Analyses-Of-Record) for PVNGS Units 1, 2, and 3. 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 PVNGS Units 1, 2 and 3.
5
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 ZIRLOTM Cladding Material in CE Nuclear Power Fuel Assembly Designs," November 2001.
- 3. Letter dated December 9, 2000, S.A. Richards (NRC) to P.W. Richardson (Westinghouse), "Safety Evaluation of Topical Report CENPD-1 32, Supplement 4, Revision 1, 'Calculative Methods for the CE Nuclear Power Large Break LOCA Evaluation Model' (TAC No. MA5660)."
- 4. Letter dated September 12, 2001, S.A. Richards (NRC) to P.W. Richardson (Westinghouse), "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)."
- 5. Letter 102-04623-CDM/TNW/JAP, dated November 9, 2001, "Request for Amendment to Technical Specification 5.6.5b, Core Operating Limits Report (COLR)," from David Mauldin, APS to USNRC.
- 6. Letter dated March 12, 2002, Jack Donohew (USNRC) to G. R. Overbeck (Arizona Public Service Company), "PVNGS, Units 1, 2, and 3 - Issuance of Amendments RE: Technical Specification 5.6.5b, Core Operating Limits Report (COLR) and use of ZIRLO Cladding Material, (TAC Nos. MB3373, MB3374, and MB3375)."
- 7. CENPD-1 32, Supplement 3-P-A, "Calculative Methods for the C-E Large Break LOCA Evaluation Model for the Analysis of C-E and W Designed NSSS," June 1985.
- 8. CENPD-1 37, Supplement 2-P-A, "Calculative Methods for the ABB CE Small Break LOCA Evaluation Model," April 1998.
- 9. Letter dated December 16, 1997, T.H. Essig (NRC) to I.C. Rickard (ABB Combustion Engineering), "Acceptance for Referencing of the Topical Report CENPD-1 37(P), Supplement 2, 'Calculative Methods for the C-E Small Break LOCA Evaluation Model' (TAC No. M95687)."
10.CENPD-137, Supplement 1-P, "Calculative Methods for the C-E Small Break LOCA Evaluation Model," January 1977.
- 11. Letter 102-04641 -CDM/RAB, dated December 21, 2001, "PVNGS Unit 2 - Request for a License Amendment to Support Replacement of Steam Generators and Uprated Power Operations," from David Mauldin, APS to USNRC.
6
Table 1 Comparison of Important Parameters Used in the Current and New PVNGS Units 1, 2 and 3 LBLOCA ECCS Performance Analysis Parameter Previous New Analysis Analysis LBLOCA Evaluation Model 1985 EM 1999 EM Core Power Level, MWt (including power 4070 4070 measurement uncertainty)
Peak Linear Heat Generation Rate, kW/ft 13.1 13.1 Hot Rod Pin-to-Box Factor 1.03 1.03 RCS Flow Rate, Ibm/hr 147.6xl0" 147.6xlob RCS Pressure, psia 2250 2250 Cold Leg Temperature, OF 541 541 Hot Leg Temperature, OF 611 611 Steam Generators Original Original/
SteamGeneratorPluggedTubeG 10 15Replacement Steam Generator Plugged Tubes/SG 1750 1750 Table 2 Comparison of Important Results of the Current and New PVNGS Units 1, 2 and 3 LBLOCA ECCS Performance Analysis Parameter Previous New Analysis Analysis Limiting Break Size 0.6 0.6 0.8 DEG/PDa DEG/PDb DEG/PDc Cladding Material Zircaloy Zircaloy ZIRLO TM Peak Cladding Temperature, oF 2174 2110 2087 Time of Peak Cladding Temperature, 250 266 232 seconds Maximum Cladding Oxidation, %
8.37 7.6 12.0 Maximum Core-Wide Cladding Oxidation,
<0.86
<0.57
<0.73 Time of Cladding Rupture, seconds 36 48 26
- a.
- b.
C.
DEG/PD = Double-Ended Guillotine Break in Pump Discharge Leg Case of Maximum Cladding Temperature Case of Maximum Local Cladding Oxidation 7
Table 3 Comparison of Important Parameters Used in the Current and New PVNGS Units 1, 2 and 3 SBLOCA ECCS Performance Analysis Parameter Previous New Analysis
__________________________New__AnalAalyss Analysis SBLOCA Evaluation Model SiM S2M Core Power Level, MWt (including power 4070 4070 measurement uncertainty)
Peak Linear Heat Generation Rate, kW/ft 13.5 13.5 RCS Flow Rate, Ibm/hr 147.6xlOb 147.6x106 RCS Pressure, psia 2250 2250 Cold Leg Temperature, OF 541 541 Hot Leg Temperature, OF 612 612 Steam Generators Original Original/
Replacement Steam Generator Tube Plugging, plugged 2750 2750 tubes/SG I
Table 4 Comparison of Important Results of the Current and New PVNGS Units 1, 2 and 3 SBLOCA ECCS Performance Analysis Parameter Previous New Analysis Analysis Limiting Break Sizea 0.05 fte/PD0 0.05 ftWIPDf Peak Cladding Temperature, OF 1907 1618 Time of Peak Cladding Temperature, 1568 1592 seconds Maximum Cladding Oxidation, %
3.57 1.28 Maximum Core-Wide Cladding Oxidation, %
<0.57
<0.2 Time of Cladding Rupture, seconds No Rupture No Rupture
- a.
Break that resulted in the highest peak cladding temperature
- b.
PD = Pump Discharge Leg 8