ML20149L490
| ML20149L490 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 07/28/1997 |
| From: | Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NYN-97088, NUDOCS 9708010233 | |
| Download: ML20149L490 (9) | |
Text
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North North Atlantic Energy Service Corporation 5
i P.O. Box 300 t
Atlantic seahreet. Nii O3874 I
(603) 474-9521 The Northeast Utilitica System 4
July 28,1997 Docket No. 50-443 NYN-97088 United States Nuclear Regulatory Commission i
Attention: Document Control Desk Washington, D.C. 20555 Seabrook Station North Atlantic Reporting Of Changes To, And Errors In, Emergency Core Cooling Systems Models Or Aonlications in accordance with the requirements of 10 CFR 50.46(aX3Xii), North Atlantic Encrgy Service Corporation (North Atlantic) hereby submits changes to, and errors in, the emergency core cooling system (ECCS) evaluation model or application of the model for Seabrook Statio i for the period from July 9,1996 to June 27,1997.
The last update was submitted to the NRC on December 27,1996, and provided the annual 10 CFR 50.46 report for Seabrook Station for the period from July 26,1995 to July 8,1996. Based on notifications received from Westinghouse Electric Corporation dated February 17,1997, May 8,1997, and June 27, 1997, this report covers additional changes to or errors in the large ' reak loss of coolant accident c
(LELOCA) and the small break loss of coolant accident (SBLOCA) analyses performed for Seabrook Station since July 8,1996. The following is a synopsis of the information provided in Attachment 1.
FEBRUARY 17.1997 CIIANGES AND ERRORS For the LBLOCA analysis an error was discovered in the coding related to the translation of fluid conditions between the SATAN blowdown hydraulics code and the LOCTA code used for subchannel analysis of the fuel rods. In performing axial interpolations to translate the SATAN fluid conditions onto the mesh nodalization used by the LOCTA code, the length of the lower core channel fluid connections to the lower plenum node was incorrectly calculated.
The effect of the error results in a 15 degrees Fahrenheit peak clad temperature penalty on the BASH large break LOCA evaluation model used for Seabrook's LBLOCA analysis. Since the cumulative efTect of the po\\
LBLOCA evaluation model changes and errors to the NRC approved ECCS evaluation model of record is greater than 50 degrees Fahrenheit, this error is classified as significant with respect to 10 CFR 50.46(aX3Xi) and the guidance contained in NRC Information Notice 97-15 issued April 4,1997 and, as such, is being reported as required by 10 CFR 50.46(aX3Xii).
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United States Nuclear Regulatory Commission i
NYN-97088/Page 2 MAY 8 AND JUNE 27.1997 PEAK CLAD TEMPERATURE MARGIN ALLOCATIONS During Seabrook Station's Cycle 6 core reload analysis, Westinghouse Electric Corporation provided reload evaluation input assessment and LOCA peak clad temperature margin utilization updates on May 8 and June 27,1997. While no changes to or errors in the current ECCS evaluation model were reported in these i
updates, margin allocations were made as a result of evaluations performed to support a 100 percent power steady state Reactor Coolant System average temperature (T-AVG) operating band of 583.5 to 593.5 degrees Fahrenheit. The ten degree T-AVG operating band resulted in a peak clad temperature margin allocation penalty of 25 degrees Fahrenheit for the LBLOCA and a penalty of 40 degrees Fahrenheit for the SBLOCA analyses.
PEAK CLAD TEMPERATURE MARGIN ALLOCATION SIIEETS provides the LBLOCA and SBLOCA ECCS Evaluation Model Margin Utilization for: (A) the analysis of record; (B) prior perme.nent 10 CFR50.46 LOCA model assessments; (C) margin utilizations attributable to 10 CFR 50.59 evaluations up to the present; (D) 1997 10 CFR50.46 LOCA model assessments including those for which this notification is being performed; and (E) other margin allocations including those summarized in the preceding paragraphs.
Considering the new changes and errors summarized in this letter and listed in Attachment 1, the corrected licensing basis peak clad temperature including the additional margin allocations for the LBLOCA and SBLOCA analyses remains below the 2200 degree Fahrenheit limit as defined by 10 CFR 50.46(b)(1).
We believe that this information satisfies the reporting requirements of 10 CFR 50.46(aX3Xii).
ItECONCILIATION OF PREVIOUSLY REPORTED CIIANGES TO. ERitORS IN. AND APPLICATIONS OF TIIE ECCS EVALUATION MODEL As a result of our review of NRC Information Notice 97-15, we have evaluated previous 10 CFR 50.46 annual ECCS evaluation model peak clad temperature repods. We have determined that cenain changes to and errors in the current NRC approved ECCS evaluation model of record should have been reported as sir,uificant as defined in 10 CFR50.46(a)(3Xi) and should have been reported within 30 days as required by 10 CFR 50.46(aX3Xii). The previous reports addressed net changes for the reporting period and as a result did not specifically address individual absolute changes greater than 50 degrees Fahrenheit nor the cumulative net change to the analysis of record being greater than 50 degrees Fahrenheit. Attachment 2 lists ti.e changes reported in the past annual reports since the time the current ECCS evaluation of record was approved. The licensing basis peak clad temperature including the margin assessments for the LBLOCA and SBLOCA analyses, has not exceeded the 2200 degree Fahrenheit limit specified in 10 CFR 50.46(bX1).
1 United States Nuclear Regulatory Commission NYN-97088/Page 3 l
l Should you' have any questions regarding this report, please contact Mr. Terry L. Ilarpster, Director of Licensing Services, at (603) 773-7765.
.Very truly yours, NORTH ATLANTIC ENERGTS -RVICE CORP.
1 AW l
C. Fegdbaum
[
Executive Vi President and Chief Nuclea ec:
IL J. Miller, Regional Administrator A. W. De Agazio, Sr. Project Manager F. P. Bonnett, NRC Senior Resident Inspector
ATTACHMENT 1 Small Break Peak Clad Temperature Margin Utilization ECCS EVALUATION MODEL REVISIONS / ERRORS 10 CFR 50.46 ANNUAL REPORT Evaluation Model : NOTRUMP Fuel: 17x17 V5H FQ=2.5 F A H=1.65 SGTP=13%
3411 M Wt Clad Temperature A.
ANALYSIS OF RECORD (8/93) 1.
1082 *F 2.
Increased T-AVG Uncertainty for RTD Bypass Elimination APCT=
8F B.
PRIOR PERMANENT ECCS MODEL ASSESSMENTS APCT=
38 F C.
10 CFR 50.59 SAFETY EVALUATIONS 1.
PSV/MSSV Setpoint Tolerance Relaxation APCT=
5F D.
199710 CFR 50.46 MODEL ASSESSMENTS APCT=
0F E.
OTHER MARGIN ALLOCATIONS 1.
EFW Actuation on SI Signal Only APCT=
5F 2.
+/- 5 F T-AVG Window APCT=
40 F LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =
1178 F
j ATTACIIMENT I (CONT) l l
l Large Break Peak Clad Temperature Margin Utilization ECCS EVALUATION MODEL REVISIONS / ERRORS 10 CFR 50.46 ANNUAL REPORT l
Evaluation Model : NOTRUMP Fuel: 17x17 V5H FQ=2.5 i
F A 11=1.65 SGTP=13%
3411 MWt 1
Clad Temperature A.
ANALYSIS OF RECORD (8/93) 1.
1889 F 2.
Increased T-AVG Uncertainty for RTD Bypass Elimination APCT=
5F B.
PRIOR PERMANENT ECCS MODEL ASSESSMENTS APCT=
58 F l
C.
10 CFR 50.59 SAFETY EVALUATIONS APCT=
0 F D.
199710 CFR 50.46 MODEL ASSESSMENTS (Permanent Assessment of PCT Margin) 1.
T ranslation of Fluid Conditions from SATAN /LOCTA APCT=
15 'F i
E.
OTHER MAttGIN ALLOCATIONS l
1.
+/- 5 F T-AVG Window APCT=
25 F LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =
1992 F 4
i
l l
l.
ATTACIIMENT 2 RECONCILIATION OF PREVIOUSLY REPORTED CIIANGES TO, ERRORS IN AND APPLICATIONS OF TIIE ECCS EVALUATION MODEL i
1995 Small Break Peak Clad Temperature Margin Utilization j
Evaluation Model : NOTRUMP Fuel: 17x17 V5f t FQ=2.5 F A 11=1.65 SGTP=13%
3411 MWt Clad Temperature As reported in 1995 Reconciliation A.
ANALYSIS OF RECORD (8/93) l 1.
Increased T-AVG Uncertainty fo-RTD Bypass Elimination APCT= 8 F B.
PRIOR PERMANENT ECCS MODEL ASSESSMENTS APCT= 8 F APCT= 0 F C.
10 CFR 50.59 SAFETY EVALUATIONS l.
PSV/MSSV Setpoint Tolerance Relaxation APCT= 5 F l
D.
199510 CFR 50.46 MODEL ASSESSMENTS APCT= 0 F (Permanent Assessment of PCT Margin) i NOTE-Tile FOLLOWING 10 CFR 50.46 MODEL ASSESSMENTS WERE REPORTED TO NORTH ATLANTIC BY WESTINGilOUSE DURING 1994 AND WERE INCORRECTLY SUMMED AND REPORTED AS ITEM B ABOVE BY NORTH ATLANTIC IN TIIE 1995 ANNUAL 10 CFR 50.46 REPORT. TilEY SilOULD IIAVE BEEN LISTED AS 1995 MODEL ASSESSMENTS UNDER D ABOVE:
l 1.
Effect of Si in Broken Loop APCT= 150 F i
2.
Effect ofimproved Condensation Model APCT= -150 F l
3.
Drift Flux Flow Regime Errors APCT= -13 F 4.
LUCIFER Error Corrections APCT= -16 F l
5.
Boiling IIeat Transfer Correlation Error APCT= -6 F
l 6.
Steam Line Isolation Logic Error APCT= 30 F 7.
Axial Nodalintion, RIP Model Revision APCT= 13 F cnd SBLOCTA Error Correction Analysis LICENSING HASIS PCT + MARGIN ALLOCATIONS PCT =1103 F; RECONCILED 1103 F i
l' ATTACllMENT 2 (CONT)
RECONCILIATION OF PREVIOUSLY REPORTED CIIANGES TO, ERRORS IN AND APPLICATIONS OF TIIE ECCS EVALUATION MODEL l
1996 Small Break Peak Clad Temperature Margin Utilization Evhiuation Model : NOTRUMP Fuel: 17x17 V5H FQ=2.5 F A H=1.65 SGTP=13%
3411 MWt l
Clad Temnerature As reported in 1996 Reconciliation A.
ANALYSIS OF RECORD (8/93) 1.
Increased T-AVG Uncertainty for RTD Bypass Elimination APCT= 8 F l
l B.
PRIOR PERMANENT ECCS MODEL ASSESSMENTS APCT= 28 F APCT= 8 F C.
10 CFR 50.59 SAFETY EVALUATIONS 1.
PSV/MSSV Setpoint Tolerance Relaxation APCT= 5 F l
D.
199610 CFR 50.46 MODEL ASSESSMENTS (Permanent Assessment of PCT Margin) 1.
SBLOCTA Fuel Rod Initialization Error APCT= 10 F NOTE-THE NOTRUMP ERROR LISTED BELOW WAS INCORRECTLY LISTED AS A PRIOR PERMANENT MODEL ASSESSMENTIN B ABOVE. IT SHOULD HAVE BEEN LISTED AS A 1996 l
MODEL ASSESSMENT.
l 2.
NOTRUMP Specific Enthalpy Error APCT= 20 F E.
OTHER MARGIN ALLOCATIONS 1.
EFW Actuation on SI Signal Only APCT= 5 F LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =1138 F; RECONCILED 1138 F
4.
O ATTACIIMENT 2 (CONT)
RECONCILIATION OF PREVIOUSLY REPORTED CIIANGES TO, ERRORS IN AND APPLICATIONS OF TIIE ECCS EVALUATION MODEL 1995 Large Break Peak Clad Temperature Margin Utilization Evaluation Model: NOTRUMP Fuel: 17x17 V511 FQ=2.5 F A 11=1.65 SGTP=13%
3411 MWt Clad Temperature As reported in 1995 Reconciliation A.
ANALYSIS OF RECORD (8/93) 1.
Increased T-AVG Uncertainty for RTD Bypass Elimination APCT= 5 F B.
PRIOR PERMANENT ECCS MODEL ASSESSMENTS APCT= -6 F
APCT= 0 F j
C.
10 CFR 50.59 SAFETY EVALUATIONS APCT= 0 F l
D.
199510 CFR 50.46 MODEL ASSESSMENTS (Permanent Assessment of PCT Margin) 1.
Skewed Power Shape Penalty APCT= 64 F 2.
Ilot leg Nozzle Gap Benefit APCT= -142 F NOTE-TliE FOLLOWING 10 CFR 50.46 MODEL ASSESSMENT WAS REPORTED TO NORTil ATLANTIC BY WESTING 110USE L)URING 1994 AND WAS INCORRECTLY REPORTED AS ITEM B ABOVE BY NORTH ATLANTIC IN Tile 1995 ANNUAL 10 CFR 50.46 REPORT. IT SilOULD HAVE BEEN LISTED AS A 1995 MODEL ASSESSMENT UNDER D ABOVE:
1.
LUCIFER Error Corrections APCT= -6 F LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =1810 F; RECONCILED 1810 F
e l
ATTACIIMENT 2 (CONT)
RECONCILIATION OF PREVIOUSLY REPORTED CIIANGES TO, ERRORS IN AND APPLICATIONS OF TIIE ECCS EVALUATION MODEL l
1996 Large Break Peak Clad Temperature Margin Utilization Evaluation Model : NOTRUMP Fuel: 17xl7 V5H FQ=2.5 F A H=1.65 SGTP=13%
3411 MWt Clad Temperature l
As reported in 1996 Reconciliation I
A.
ANALYSIS OF RECORD (8/93) 1.
Increased T-AVG Uncertainty for RTD Bypass Elimination APCT= 5 F j
B.
PRIOR PERMANENT ECCS MODEL ASSESSMENTS APCT= 58 F APCT= - 84 F C.
10 CFR 50.59 SAFETY EVALUATIONS APCT= 0 F l
D.
199610 CFR 50.46 MODEL ASSESSMENTS APCT= 0 F (Permanent Assessment of PCT Margin)
NOTE-Tile HOT LEG NOZZLE GAP BENEFIT WAS REPORTED IN Tile 199510 CFR 50.46 ANNUAL REPORT.' BASED ON WESTINGHOUSE'S WITilDRAWAL OF THEIR REQUEST TO THE NRC FOR APPROVAL OF TIIE POWER SHAPE SENSITIVITY MODEL(PSSM) WillCH WAS THE BASIS FOR Tile BENEFIT, NORTil ATLANTIC ADDED AN OFFSETTING PENALTY TO l
COMPENSATE FOR tills ITEM. HOWEVER, Tile PENALTY WAS INCORRECTLY ADDED TO THE PRIOR PERMANENT MODEL ASSESSMENT LISTED IN B ABOVE IN Tile 1996 REPORT. IT l
SilOULD IIAVE BEEN ITEMIZED AS A 1996 MODEL ASSESSMENT.
l 1.
Withdrawal ofIlot Leg Nozzle Gap Benefit APCT= 142 F LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =1952 F; RECONCILED 1952 F b
i e