ML13330B540
| ML13330B540 | |
| Person / Time | |
|---|---|
| Site: | San Onofre  |
| Issue date: | 07/29/1991 |
| From: | Rosenblum R SOUTHERN CALIFORNIA EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| Shared Package | |
| ML13329A747 | List: |
| References | |
| NUDOCS 9108020162 | |
| Download: ML13330B540 (3) | |
Text
Southern Caifornia Edison Company 23 PARKER STREET IRVINE, CALIFORNIA 92718 R. M. ROSENBLUM TELEPHONE MANAGER OF July 29, 1991 (714) 454-4505 NUCLEAR REGULATORY AFFAIRS U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D. C. 20555 Gentlemen:
Subject:
Docket No. 50-206 10CFR50.63, Station Blackout San Onofre Nuclear Generating Station, Unit 1 This letter proVides copies of our analyses demonstrating that both the reactor coolant system (RCS) inventory and the station battery capacity will be adequate to survive a four hour station blackout. Submittal of these analyses meets commitments made in our December 5, 1990 letter. The evaluations are provided as Enclosures 1 and 2, respectively. The RCS inventory calculation demonstrates that the reactor core will remain covered during a station blackout. The battery capacity evaluation shows that Battery No. 1 on Train A has sufficient capacity to cope with a four hour station blackout; however, Battery No. 2 on Train B must be replaced with a larger battery to.cope with a four hour station blackout.
On July 23, 1991, we received our Station Blackout Safety Evaluation Report (SER) dated July 10, 1991. In order to satisfy the 30 day response to the SER required by 10 CFR 50.63 c(4), this letter also provides our schedule for implementing the station blackout battery modification and procedure changes.
RCS Inventory The enclosed RCS inventory calculation demonstrates that adequate coolant inventory will be retained with a station blackout to keep the reactor core covered. In accordance with NUMARC 87-00, the calculation assumes that the reactor coolant pump seals leak at 25 gpm per pump. The calculation also assumes the total of unidentified plus identified leakage is 6 gpm which is the maximum value allowed by the Technical Specifications. The letdown isolation valves are assumed to leak at 20 gpm when isolated. Using these assumptions, a total RCS leakage of 101 gpm is used in the calculation which shows that the reactor core remains covered during the entire SBO.
Battery Capacity The enclosed battery capacity calculation demonstrates that Battery No. 1 on Train A has sufficient capacity to cope with the four hour station blackout duration, although some load stripping is required. The specific loads which must be removed are listed in the calculation. The control room will remain 9108020162 9107:29 PDR ADOCK 05000206 F.
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-2 functional and the instrumentation needed to monitor critical parameters will be available. The bases for removing the loads from the battery are included in Enclosure 3.
We have also completed an evaluation for Battery No. 2 on Train B, and have determined that it must be replaced with a larger battery having sufficient capacity for a four hour station blackout.
Station Blackout Implementation Schedule The Station Blackout regulations require plant modifications and procedures to be implemented within two years of receiving the SER or that a justification for schedular extension be provided with the 30 day response letter. Two years from the date of the SER would occur in July 1993 during Cycle 12 operation. Performing the battery modification during the Cycle 12 refueling outage would allow us to satisfy the two year requirement. As you are aware, we are currently performing the engineering for the Cycle 12 FTOL items which require modifications. Since we are unable to schedule any additional modifications during the Cycle 12 outage, we plan to perform the battery modification during the Cycle 13 refueling outage.
Implementation of the changes required to satisfy the station blackout rule, with the exception of the modification to Battery No. 2, will be completed prior to Cycle 12 operation. This includes the procedure revisions identified in the January 2, 1991 FTOL order, satisfing the FTOL order committment. The battery modification will be completed in Cycle 13 in accordance with the station blackout rule, 10 CFR 50.63.
If you have any questions, please do not hesitate to call.
Very truly yours, Enclosures cc:
George Kalman, NRC Senior Project Manager, San Onofre Unit 1 J. 0. Bradfute, NRC Project Manager, San Onofre Unit 1 J. B. Martin, Regional Administrator, NRC Region V C. W. Caldwell, NRC Senior Resident Inspector, San Onofre Units 1, 2&3
SPECIAL INSTRUCTIONS RE: UNDATED LETTER Attention: Document Control Desk
Subject:
Docket No. 50-206 Station Blackout Letter San Onofre Nuclear Generating Station, Unit 1 On July 30, 1991 you received a letter from us regarding station blackout. The letter was inadvertently not dated. We have discussed this matter with our NRC Project Manager, George Kalman, who requested that we send a dated copy to the Document Control Desk. Accordingly, enclosed is a copy of the letter with the July 29, 1991 date. Please discard the entire undated submittal and replace it with the submittal enclosed in this package. We regret the inconvenience this has caused.
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