ML20207T806
| ML20207T806 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna, 05000000 |
| Issue date: | 02/20/1987 |
| From: | Stewart W VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| To: | Grace J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| References | |
| REF-PT21-87, REF-PT21-87-070-000, REF-PT21-87-082-000 87-082, 87-82, PT21-87-070-000, PT21-87-70, NUDOCS 8703240361 | |
| Download: ML20207T806 (3) | |
Text
s VINGINIA ELzcrRIC AND POWEN COMI*ANY HICliMONn,VInoINIA 2:32 61
, fee 23 AIO : 34 February 20, 1987 Vers Pommiassar Nectuam orumArsons Dr. J. Nelson Grace Serial No.87-082 Regional Administrator N0/JDH:vlh Region II Docket Nos.
50-280 U. S. Nuclear Regulatory Commission 50-281 Suite 2900 50-338 101 Marietta Street, N. W.
50-339 Atlanta, Georgia 30323 License Nos.
Dear Dr. Grace:
VIRGINIA ELECTRIC AND POWER COMPANY SUERY POWER STATION UNITS 1 AND 2 NORTH ANNA POWER STATION UNITS 1 AND 2 NOTIFICATION PURSUANT TO 10 CFR 21 Ws have received information indicating that a basic component supplied to our facilities contained a defect which could potentially create a substantial safety hazard.
This information was provided by Mr. R. J. Hardwick, Jr. to Mr. F. S. Cantrell of your staff on February 18, 1987.
In accordance with the reporting requirements of 10 CFR 21.21, the following information is provided:
A.
Name and address of reporting individual:
W. L. Stewart, Vice President - Nuclear Operations Virginia Electric and Power Company P. O. Box 26666 Richmond, Virginia 23261 B.
Identification of the facility and basic component which contains a defect:
Surry Power Station Units 1 and 2 Recirculation Spray Heat Exchangers l
l North Anna Power Station Units 1 and 2 l
Recirculation Spray Heat Exchangers ffh 05000280 870220 S
l PDR I g
- 7 Elf
C.
Identification of firm supplying basic component:
Surry Stone & Webster Engineering Corporation, Boston, MA (component manufactured by Yuba Heat Transfer Division of Yuba Industries, Inc.).
North Anna Stone & Webster Engineering Corporation, Boston, MA (component manufactured by Joseph Oat and Sons, Inc.).
D.
Nature of the defect and the safety hazard which could be created:
The recirculation spray heat exchanger design provides for a diaphragm seal plate welded to the heat exchanger head flange.
The original design did not consider external pressurization of the diaphragm seal plate without the presence of an internal pressure to balance the resulting forces.
Recent analyses indicate that the design could undergo only a limited number of overpressurization cycles (such as those experienced during Type A testing or DBA conditions) before exceeding the fatigue life of the diaphragm plate.
Failure of the diaphragm plate under accident conditions could result in loss of containment integrity and a potential flowpath for release of radioactive effluents via the service water system to the environment.
E.
Date on which information of such defect was obtained:
February 17, 1987 F.
The number and location of all such components in use:
Surry 1 and 2 Four per unit, located inside containment North Anna 1 and 2 Four per unit, located inside containment G.
Corrective action, individual responsible for action, and length of l
time for corrective action:
Surry Both units are currently in cold shutdown following the December 9, 1986 Surry 2 event.
A modification consisting of installing a thicker diaphragm designed to withstand full external pressure l
loading without exceeding the material design allowable stresses will be installed in the heat exchangers prior to restart.
1 l
North Anna Both units are currently operating.
Analyses of the allowable overpressurization cycles is ongoing and is expected to be completed by March 3, 1987. Preliminary results of this analysis indicate that the number of allowable overpressurization cycles has not been exceeded.
A permanent modification will be scheduled for implementation during each unit's next refueling outage.
The individual responsible for the corrective action is William L.
Stewart, Vice President - Nuclear Operations.
H.
Advice related to the defect:
None Very truly yours,
\\
W. L. Stewart i
cc:
U. S. Nuclear Regulatory Commission l
Attention: Document Control Desk Washington, D.C.
20555 Mr. James M. Taylor, Director (3 copies)
Office of Inspection end Enforcement U. S. Nuclear Regulatory Commission Mr. W. E. Holland NRC Senior Resident luspector Surry Power Station Mr. J. L. Caldwell NRC Senior Resident Inspector North Anna Power Station
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