ML13317B248
| ML13317B248 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 12/05/1990 |
| From: | Nandy F SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9012100269 | |
| Download: ML13317B248 (2) | |
Text
Southern California Edison Company 23 PARKER STREET IRVINE, CALIFORNIA 92718 F. R. NANDY December 5, 1990 TELEPHONE MANAGER. NUCLEAR LICENSING (714) 454-4504 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
Subject:
Docket No. 50-206 10 CFR 50.63, Station Blackout San Onofre Nuclear Generating Station, Unit 1 This letter informs you that we have decided to eliminate use of the DC thermal barrier pump from our method of compliance with the station blackout rule. Because of this change in compliance, a deviation from the NUMARC 87-00 guidance on reactor coolant inventory will no longer be required. We have also determined that a new deviation from the NUMARC 87-00 HVAC guidance will be required for our HVAC calculations. These changes will delay submittal of the information requested by the NRC in our June 22, 1990 telephone conversation. A partial response to these questions was provided in our August 6, 1990 letter.
DC Thermal Barrier Pump We will perform a reactor coolant inventory loss calculation based on the guidance in NUMARC 87-00 instead of crediting the DC thermal barrier pump to control reactor coolant pump seal leakage. The deviation from NUMARC 87-00 guidance on RCS inventory in our May 1, 1990 submittal will no longer be required. Because the thermal barrier pump will no longer be credited, the NRC questions regarding the pump are no longer applicable to our compliance methodology.
Station Battery Evaluation Completion of the battery calculation will be delayed until the RCS inventory calculation is finished. This will allow us to revise the battery calculation, as necessary, to remove the DC thermal barrier pump from the battery loads.
HVAC Calculation The calculation addressing a loss of HVAC in the DC Switchgear Room has been completed. However, we have determined that a deviation from the NUMARC 87-00 guidance is necessary in order to predict acceptable temperatures after loss 9Ci.Rt)C 2 '
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Document Control Desk December 5, 1990 of HVAC. We have also determined that the same deviation is necessary for other plant areas. We will provide the NRC staff with an additional submittal which explains and provides justification for the deviation.
Response Schedule We will provide a submittal summarizing the results of the RCS leakage calculation and the station battery evaluation within four months after restart from the Cycle 11 refueling outage. We will also provide a submittal explaining the HVAC deviation and the results of the calculation for the DC Switchgear Room by December 21, 1990.
If you have any questions, please do not hesitate to call me.
Very truly yours, cc: J. B. Martin, Regional Administrator, NRC Region V C. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1, 2 and 3 C. D. Townsend, NRC Resident Inspector, San Onofre Unit 1 A. Marion (NUMARC)