ML18153C458
| ML18153C458 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 11/29/1990 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 90-661, NUDOCS 9012070144 | |
| Download: ML18153C458 (2) | |
Text
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e VIRGINIA ELECTRIC AND POWER COMPANY RICHMOND, VIRGINIA 23261 November 29, 1990 U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D.C. 20555 Gentlemen:
VIRGINIA ELECTRIC AND POWER COMPANY SURRY POWER STATION UNITS 1 AND 2 NORTH ANNA POWER STATION UNITS 1 AND 2 Serial No.*
90-661 NL&P/RMN: R4 Docket Nos.
50-280 50-281 50-338 50-339 License Nos. DPR-32 DPR-37 NPF-4 NPF-7 RESPONSE TO STATION BLACKOUT SAFETY EVALUATION REPORTS We have received your October 15, 1990 and *October 18, 1990 Safety Evaluation Reports for Surry and North Anna, respectively, which requested responses from us within 60
- days.
The SERs were in response to our April 17, 1989 letter which described our proposal for compliance with the Station Blackout (SBO) rule, 1 O CFR 50.63. We proposed adding an additional emergency diesel generator at Surry so that each station would have four EDGs. We would then have used cross ties so that the blacked out unit could use the excess capacity from the non-blacked out unit. In your SERs you rejected this approach and recommended that we "undertake further measures such as providing an independent AAC (alternate AC) power source or a coping analysis which shows that the plant can cope with and recover from a SBO."
We have reevaluated various options to comply with 10 CFR 50.63 and are currently pursuing the feasibility of the installation of an independent, non-safety grade diesel at North Anna and two non-safety grade diesels at Surry. In this option, each proposed diesel would be large enough to fully power one emergency bus with the capability to connect these alternate AC sources to any of the three transfer busses and, therefore, to any emergency bus. We would also have the capability to cross tie the D and E transfer busses at each station.
\\
Fu*11 development of this option involves a major engineering effort. During the time frame for this study, three of our four units will be involved in a refueling outage which involves the same engineering resources.
Therefore, we can not provide a full response within the 60 days you requested. Accordingly, we will initially supplement the status for both stations by April 30, 1991 and quarterly thereafter until the final response is made.
Because the October 15 and 18, 1990 safety evaluation reports rejected our basic approach to resolution of the station blackout issue, we do not consider them to be the notification described in 1 OCFR 50.63(c)(3) that requires us to submit a schedule within thirty days for implementation of appropriate modifications and procedures within two years. We will address the schedule for modifications in a later submittal.
Implementation is expected to take longer than the two years described in the rule and additional justification for the schedule will be provided.
If you have any questions or require additional information, please contact us.
Very truly Y, (2
W. L. Ste art Senior Vice President - Nuclear cc:
U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, N.W.
Suite 2900 Atlanta, Georgia 30323 Mr. M. S. Lesser NRC Senior Resident Inspector North Anna Power Station Mr. W. E. Holland NRC Senior Resident Inspector Surry Power Station