ML19257A317
| ML19257A317 | |
| Person / Time | |
|---|---|
| Site: | North Anna  |
| Issue date: | 12/11/1979 |
| From: | Brown S VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | |
| References | |
| 1116, NUDOCS 8001030725 | |
| Download: ML19257A317 (2) | |
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VIRGINS A ELECTRIC AND POWER COMP ANY, RICMMON C. VI RGINi a 23261
- [ q l3 A j; 24 December 11, 1979 Mr. James P. O'Reilly, Director Serial No. 1116 Office of Inspection & Enforcement PSE&C/JCHjr:mac: wang U.S. Nuclear Regulatory Comission Region II Docket No. 50-339 101 Marietta Street, Suite 3100 Atlanta, Georgia 30303
Dear Mr. O'Reilly:
On December 7,1979 a report was made under the provisions of 10CFR50.55(e) concerning the Departure from Nucleate Boiling Ratio (DNBR)
Limit.
In accordance with the reporting requirements of 10CFR21, the following information is submitted:
A.
Name and address of reporting individual:
Mr. E. A. Baum, Executive Manager Licensing and Quality Assurance Virginia Electric and Power Company P. O. Box 26666 Richmond, Virginia 23261 8.
Facility, activity and/or component affected:
North Anna Power Station, Unit 2 DNBR Limit C.
Name of firm constructing the facility or supplying the component, activity or service:
Westinghouse Electric Corporation, P. O. Box 355 Pittsburgh, Pennsylvania 15230 D.
Description of defect, deficiency, or failure to comply:
A nonconservatism was found in the method used to generate power distributions and rod worths for dropped rod events. New analyses have been performed using a more conservative reactivity feedback model and the results indicate that certain multiple rod drop events may not trip the reactor as previously assumed.
E.
Date of determination of reportability:
December 7, 1979 lffg 3j4 WT 8 0 010 3 0 [$m4;.cnev
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F.
Similar components, activities, or services:
North Anna' Unit 1 G.
Corrective action which has been, is being or will be taken, the individual responsible and the length of time to complete the action:
The corrective action is to implement the following procedural solution when applicable.
Manual Rod Control 0-100% Power: No change from current rod insertion limit.
(i.e., Technical Specification 3.1.3.6, North Anna 2)
Automatic Rod Control 0 to 90% Power: No change from current rod insertion limit.
(i.e., Technical Specification 3.1.3.6, North Anna 2) 90 to 100% Power: D bank greater than 215 steps.
The benefit of this solution is that it will minim'ze a power overshoot for rod drop events and preclude potential DNBR limit violations. We are also continuing our review of this problem for possible implementation of long term solutions which may be more desirable.
H.
Other information:
None Any information not available at this time will be submitted in a follow-up letter as a 30-day report.
Should you require further information, please contact this office.
Very truly yours fYV/ W h.< --s dI
Sam C. Brown, Jr.
Senior Vice President - Power Station Engineering and Construction cc: Director, Office of Inspection and Enforcement (3) 1668 315 e
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