ML092600655
| ML092600655 | |
| Person / Time | |
|---|---|
| Site: | Surry  |
| Issue date: | 09/14/2009 |
| From: | Price J Virginia Electric & Power Co (VEPCO) |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| Download: ML092600655 (8) | |
Text
VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 September 14, 2009 10 CFR 50.46 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555 Serial No.
NL&OS/GDM Docket Nos.
License Nos.09-571 RO 50-280/281 DPR-32/37 VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 SUBMITTAL OF RESULTS OF SMALL BREAK LOCA REANALYSIS AND 30-DAY 10 CFR 50.46 REPORT OF EMERGENCY CORE COOLING SYSTEM fECCS) MODEL CHANGES PURSUANT TO THE REQUIREMENTS OF 10 CFR 50.46 In accordance with 10 CFR 50.46(a)(3)(ii), Virginia Electric and Power Company (Dominion) hereby submits information regarding the results of a full reanalysis of the Westinghouse Small Break Loss of Coolant Accident (SBLOCA) analyses using the NOTRUMP methodology for Surry Power Station Units 1 and 2 (SPS 1 and 2).
The attachment provides a report describing the reanalysis results for SPS 1 and 2.
The results satisfy the acceptance criteria defined in 10 CFR 50.46(b).
Dominion has determined that the peak cladding temperature (PCT) result of 2012 of for SPS 1 and 2 represents a significant change in PCT, as defined in 10 CFR 50.46(a)(3)(i), versus the previous analysis of record PCT of 1717°F. 10 CFR 50.46(a)(3)(ii) requires the licensee to provide a report within 30 days, which includes a proposed schedule for providing a reanalysis or taking other action as may be needed to show compliance with 10 CFR 50.46.
Since the PCT result described above is based on a full reanalysis, Dominion considers the schedular requirements of 10 CFR 50.46(a)(3)(ii) to be satisfied with the submission of this notification. Dominion routinely tracks adjustments to the SBLOCA calculated PCT values to ensure that reasonable margins to the acceptance value set by 10 CFR 50.46 are maintained.
If you have any questions regarding this submittal, please contact Mr. Gary Miller at (804) 273-2771.
Sincerely, n Price President - Nuclear Engineering Commitments made in this letter:
None
Serial Number 09-571 Docket Nos. 50-280/281 Page 2 of 2
Attachment:
Summary of SBLOCA Reanalysis Results and 30-Day 10 CFR 50.46 Report - Surry Power Station Units 1 and 2 cc:
U. S. Nuclear Regulatory Commission Region II Sam Nunn Atlanta Federal Center 61 Forsyth Street, S. W.
Suite 23T85 Atlanta, GA 30303-8931 Ms. K. R. Cotton NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 16 E15 11555 Rockville Pike Rockville, MD 20852-2738 Dr. V. Sreenivas NRC Project Manager U. S. Nuclear Regulatory Commission One White Flint North Mail Stop 8 G9A 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Surry Power Station
Serial Number 09-571 Docket Nos. 50-280/281 ATTACHMENT
SUMMARY
OF SBLOCA REANALYSIS RESULTS AND 30-DAY 10 CFR 50.46 REPORT SURRY POWER STATION UNITS 1 AND 2 VIRGINIA ELECTRIC AND POWER COMPANY (DOMINION)
Serial Number 09-571 Docket Nos. 50-280/281 Page 1 of 5 Summary of SBLOCA Reanalysis Results and 30-Day 10 CFR 50.46 Report Surry Power Station Units 1 and 2 Surry Units 1 and 2 utilize the Westinghouse NOTRUMP Evaluation Model for the analysis of the Small Break Loss of Coolant Accident (SBLOCA).
The analysis methodology has received NRC approval for referencing in licensing calculations as documented in WCAP-10054-P-A, Revision 0,
Westinghouse Small Break ECCS Evaluation Model Using the NOTRUMP Code, August 1985, and WCAP-10079-P-A, Revision 0, NOTRUMP, A Nodal Transient Small Break and General Network Code, August 1985.
These reports are the licensing basis methodology for Surry Units 1 and 2, as documented in Surry Technical Specification 6.2.C, Core Operating Limits
- Report, and Surry UFSAR Section 14.5.2.1.
The NOTRUMP methodology was employed for the SBLOCA reanalysis.
The SBLOCA reanalysis was performed for two key reasons:
1.
To resolve all Evaluation Model errors and changes that incur peak cladding temperature (PCT) changes against the analysis of record that was performed in 1995.
Several evaluations had been performed for SBLOCA Evaluation Model errors and plant changes.
The SBLOCA reanalysis clears all identified PCT changes that were assessed against the analysis of record, as documented in Surry UFSAR, Revision 40, Table 14.5-16, Peak Clad Temperature Including All Penalties and Benefits, Small Break LOCA.
2.
To incorporate changes in plant input parameters. The most significant change is a reduction in high head safety injection minimum delivered flow rates to provide margin for pump periodic testing.
The results of the SBLOCA analysis for Surry Units 1 and 2 are summarized in Tables 1 through 4 below.
Table 1 presents the beginning of life (BOL) fuel cladding heat up calculations, and Table 2 presents the limiting burnup calculations for the limiting 2.75 inch break case. Table 3 presents the annular pellet evaluation for the 2.75 inch break case.
NOTRUMP runs were performed for 1.5, 2, 2.25, 2.50, 2.75, 3, 4, and 5.5 inch equivalent diameter breaks.
An initial scoping study for the 3 inch break resulted in a PCT above 1700'F, prompting the use of a refined break spectrum with size spacing of 0.25 inches between the more limiting breaks of 2 inches and 3 inches.
Based on the NOTRUMP results, BOL SBLOCTA code calculations were performed for all cases, and the 2.75 inch break case produced the limiting results.
A full burnup study was performed for this break size.
Partial burnup studies for the 2.25 inch and 2.5 inch break cases were performed to confirm that the 2.75 inch break size was indeed limiting.
Serial Number 09-571 Docket Nos. 50-280/281 Page 2 of 5 The 2.75 inch break case resulted in a limiting PCT of 1984°F at 4,500 MWD/MTU, a limiting transient oxidation of 11.86% at 7,000 MWD/MTU, and the maximum total oxidation occurring at 62,000 MWD/MTU. The core wiele oxidation was calculated to be less than 1% for the entire burnup study.
Additional SBLOCTA calculations were performed to evaluate the effects of annular pellets and were determined to produce the limiting PCT of 2012°F at 5,000 MWD/MTU. The PCT has increased from 1717°F in the analysis of record to 2012°F.
The main reasons for ':he more limiting results are the reduction in high head safety injection flow rates to increase pump periodic test margins and the explicit analysis of a refined break spectrum with burnup studies.
Evaluation of 10 CFR 50.46 Acceptance Criteria Table 4 compares the most limiting results of the SBLOCA analysis to the acceptance criteria from 10 CFR 50.46(b)(1), (b)(2), and (b)(3), demonstrating acceptable margins.
The pre-transient oxidation increases with burnup from zero at BOL to a maximum value at the discharge of the fuel (end of life). It has bE'en confirmed that the sum of the pre-transient plus transient oxidation remains below 17% at all times in life.
10 CFR 50.46 criterion (b)(4) is addressed implicitly via the blockage model used when SBLOCTA predicts rod burst. Therefore, acceptance criterion (b)(4) is satisfied.
10 CFR 50.46 acceptance criterion (b)(5) requires that long-term core cooling be provided following successful initial operation of the ECCS.
Long-term cooling is dependent on the demonstration of continued delivery of cooling water to the core. The actions, automatic or manual, that are currently in place to maintain long-term cooling remain unchanged with the SBLOCA reanalysis.
10 CFR 50.46 criterion (b)(5) is addressed implicitly by the termination criteria for the NOTRUMP calculation including the extension to after switchover from injection to cold leg recirculation.
Therefore, acceptance criterion (b)(5) is satisfied.
10 CFR 50.46 Reporting Considerations Dominion has reviewed the results of the SBLOCA reanalysis for Surry Units 1 and 2.
The new PCT of 2012°F represents a "significant" change in PCT, as defined in 10 CFR 50.46(a)(3)(i), relative to the Analysis of Record (AOR) PCT of 171rF. Thus, a 30-day report to the NRC is required per 10 CFR 50.46(a)(3)(ii).
The enclosed PCT margin utilization sheets summarize the PCT results for the SBLOCA reanalysis for Surry Units 1 and 2.
10 CFR 50.46(a)(3)(ii) requires that the 30-day report include a "proposed schedule for providing a reanalysis or taking other action as may be needed to show compliance with
Serial Number 09-571 Docket Nos. 50-280/281 Page 3 of 5 Section 50.46 requirements." Since the PCT result described above is based on a full reanalysis of the SBLOCA event, Dominion considers the submittal of this 30-day report to satisfy the schedular requirements of 10 CFR 50.46(a)(3)(ii).
Table 1: SBLOCTA Results at Beginning of Life(1)
Break Size, inch 1.5 2
2.25 2.5 2.75 3
4 5.5 PCT, of 1132 1756 1802 1870 1907 1766 1442 1438 PCT Time, sec 7796.2 3303.1 2948.3 2174.3 1687.6 1451.6 700.5 363.2 PCT Elevation, ft 11.50 12.00 12.00 12.00 12.00 11.75 10.75 10.50 Maximum HR Zr02, %
0.12 3.75 5.06 4.87 4.64 2.47 0.25 0.14 Maximum HR Zr02 11.50 12.00 12.00 12.00 11.75 11.75 11.00 10.50 Elevation, ft HR Average Zr02, %
0.02 0.50 0.65 0.65 0.66 0.38 0.05 0.03 (1)
Cladding burst was not calculated to occur for any of these break sizes.
Table 2: Limiting 2.75 Inch SBLOCTA Burnup Results Burnup, MWD/MTU 4,500(1) 6000(2) 7000(3)
PCT, OF 1984 1971 1943 ii Maximum HR Transient Zr02, %
10.10 11.37 11.86 I HR Average Transient Zr02, %
0.63 0.73 0.73 (1)
The limiting time-in-life PCT was calculated to be at 4,500 MWD/MTU.
(2) The limiting time-in-life HR average transient Zr02 was calculated to be at 6,000 MWD/MTU.
(3) The limiting time-in-life HR transient Zr02 was calculated to be at 7,000 MWD/MTU.
Table 3: Limiting 2.75 Inch SBLOCTA Burnup Results with Annular Pellets I Burnup, MWD/MTU 5,000(1) 5,500(2) 6000(3)
I PCT, OF 2012 1996 1937 I Maximum HR Transient Zr02, %
11.65 11.76 11.43
! HR Average Transient Zr02, %
0.67 0.67 0.72 (1) The limiting time-in-life peT was calculated to be at 5,000 MWD/MTU.
(2) The limiting time-in-life HR transient Zr02 was calculated to be at 5,500 MWD/MTU.
(3) The limiting time-in-life HR average transient Zr02 was calculated to be at 6,000 MWD/MTU.
Table 4: Summary of Limiting Results versus 10 CFR 50.46 Acceptance Criteria Result Criterion Peak Cladding Temperature (b1) 2,012°F
< 2,200°F Local Maximum Oxidation (b2) 11.86%
<17%
Core Wide Oxidation (b3) 0.73%
< 1%
Serial Number 09-571 Docket Nos. 50-280/281 Page 4 of 5 10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE SMALL BREAK LOCA Plant Name:
Surry Power Station, Unit 1 Utility Name:
Virginia Electric and Power Company Limiting Break Size:
2.75 inches Analysis Information EM:
NOTRUMP Analysis Date:
2009 Vendor:
Westinghouse FQ:
2.5 Fuel:
SIF Notes:
None LICENSING BASIS Analysis of Record PCT PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments 1.
None F~H:
SGTP (%):
1.7 7
Clad Temp (OF) 2012 o
B.
C.
D.
Planned Plant Modification Evaluations 1.
None ECCS Model Assessments 1.
None Other 1.
None o
o o
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
2012
Serial Number 09-571 Docket Nos. 50-280/281 Page 5 of 5 Limiting Break Size:
2.75 inches 1.7 7
F~H:
SGTP (%):
10 CFR 50.46 MARGIN UTILIZATION - WESTINGHOUSE SMALL BREAK LOCA Plant Name:
Surry Power Station, Unit 2 Utility Name:
Virginia Electric and Power Compan-:y Analysis Information EM:
NOTRUMP Analysis Date:
2009 Vendor:
Westinghouse FQ:
2.5 Fuel:
SIF Notes:
None LICENSING BASIS Analysis of Record PCT Clad Temp (OF) 2012 PCT ASSESSMENTS (Delta PCT)
A.
Prior ECCS Model Assessments 1.
None o
B.
Planned Plant Modification Evaluations 1.
None o
C.
ECCS Model Assessments 1.
None o
D.
Other 1.
None o
LICENSING BASIS PCT + PCT ASSESSMENTS PCT =
2012