ML20205Q345
| ML20205Q345 | |
| Person / Time | |
|---|---|
| Site: | Seabrook  |
| Issue date: | 04/14/1999 |
| From: | Feigenbaum T NORTH ATLANTIC ENERGY SERVICE CORP. (NAESCO) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NYN-99041, NUDOCS 9904210176 | |
| Download: ML20205Q345 (5) | |
Text
E V
gT**g North Atlantic Energy Service Corporation i North
$ Atlaritic Scalerook, nil 03874 (o033 474 2i The Northeast Utilities System April 14,1999 Docket No. 50-443 NYN-99041 United States Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Se3 rook Station Reporting of Changes to, or Errors In l
b Emergency Core Cooling System Models or Applications Pursuant to the requirements of 10CFR 50.46(a)(3)(i),(ii), North Atlantic Energy Service Corporation (North Atlantic) provides notification of a temporary change in peak cladding temperature (PCT) of more than 50 degrees F. The increase in the PCT was the result of a turbine volumetric flow test, (test). The PCT penalty was applicable only during the performance of the test that commenced at 7:00 PM on March 25,1999 and was completed at 5:30 AM on March 26,1999. The test was performed at the end of the current operating cycle with the sixth refueling outage commencing on March 27,1999.
During the development of the test, the impact of a 15 degree F Tavg reduction on the
//
Large Break loss of coolant accident, (LOCA) PCT was estimated. This evaluation conservatively established a 75 degree F penalty for a Large Break LOCA. The current
/
Large Break peak cladding temperature for Seabrook Station is 1992 degrees F. The establishment on the 75 degree F penalty added to the current licensing basis Large Break LOCA PCT is 2067 degrees F, which remains below the 2200 degree F criteria identified in 10CFR 50.46. The current PCT for the Small Break LOCA for Seabrook Station is 1178 degrees F. As with the Large Break LOCA, using the 15 degree F Tavg reduction, an evaluation was performed and conservatively established a 120 degree F penalty for a Small Break LOCA. When the 120 degree F penalty is added to the current licensing basis Small Break LOCA PCT, it is 1298 degrees F, which remains below the 2200 degree F criteria established in 10CFR 50.46. Dming the conduct of the test, the actual Tavg reduction was less than 15 degrees F assumed in the PCT calculations. As a result, the actual PCT penalties would have been less than those calculated.
~
9904210176 990414 PDR ADOCK 05000443 lj; p
United States Nuclear Regulatory Commission NYN-99041/ Page 2 As described above, these PCT changes were only applicable during the performarce of
' the test. Following completion of the test, the calculated PCT for the Large Break and the.Small Break LOCA'.s returned to their prior values of 1992 degrees F and 1178 degrees F, respectively. Enclosed is a tabulation of the Large Break LOCA and Small Break LOCA Peak Clad Temperature margin utilization tables applicable to Seabrook Station during the test.
Should you have any questions regarding this report, please contact Mr. James M.
Peschel, Regulatory Compliance Manager at (603) 773-7194, Very truly yours, NORTH ATLANTIC ENERGY SERVICE CORP.
fftCh-Ted C. Feigenbauf Executive Vice President and Chief Nuclear Officer cc:
H. J. Miller, NRC Region I Administrator J. T. Harrison, NRC Project Manager, Project Directorate 1-3 R. K. Lorson, NRC Senior Resident inspector i
t
D O
t 9
4 ENCLOSURE TO NYN-99041 I
i l
Small Break Peak Clad Temperature Margin Utilization ECCS EVALUATION MODEL REVISIONS / ERRORS
'10 CFR 50.46 REPORT Evaluation Model : NOTRUMP Fuel: 17xl7 V511 FQ=2.5 F A 11=1.65 SGTP=13%
3411 MWt Clad Temperature A.
ANALYSIS OF RECORD (8/93) 1.
1082 F 2.
Increased T-AVG Uncertainty for RTD Bypass Elimination APCT=
8F j
l B.
PRIOR PERM.ANENT ECCS MODEL ASSESSMENTS APCT=
38 F j
C.
10 CFR 50.59 SAFETY EVAL.UATIONS 1.
PSV/MSSV Setpoint Tolerance Relaxation APCT=
5F l
D.
OTiiER MARGIN ALLOCATIONS 1.
EFW Actuation on SI Signal Or.ly APCT=
5F 1
2.
+/- 5 F T-AVG Window APCT=
40 F l
3.
Turbine Volumetric Flow Test (Temporary)
APCT=
120 F
}
l LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =
1298 F APPLICABLE DURING THE TEST LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =
1178 F APPLICABLE UPON COMPLETION OF Tile TEST I
Page 1 of 2 4
F (CONT)
Large Break Peak Clad Temperature Margin Utilization ECCS EVALUATION MODEL REVISIONS / ERRORS 10 CFR 50.46 REPORT Evaluation Model : NOTRUMP Fuel: 17x17 V5H FQ=2.5 F A H=1.65 SGTP=13%
3411 MWt Clad Temperature A.
ANALYSIS OF RECORD (8/93) 1.
1889 F 2.
Increased T-AVG Uncertainty for RTD Bypass Elimination APCT=
5F B.
PRIOR PERMANENTECCS MODEL ASSESSMENTS APCT=
73 F C.
10 CFR 50.59 SAFETY EVALUATIONS APCT=
0F D.
OTHER MARGIN ALLOCATIONS 1.
+/- 5 F T-AVG Window APCT=
25 F 2.
Turbine Volumetric Flow Test (Temporary)
APCT=
75 F LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =
2067 F APPLICABLE DURING THE TEST LICENSING BASIS PCT + MARGIN ALLOCATIONS PCT =
1992 F APPLICABLE UPON COMPLETION OF THE TEST Page 2 of 2