ML18143A860
| ML18143A860 | |
| Person / Time | |
|---|---|
| Site: | Ginna  |
| Issue date: | 03/24/1972 |
| From: | Amish K Rochester Gas & Electric Corp |
| To: | Morris P US Atomic Energy Commission (AEC) |
| References | |
| Download: ML18143A860 (7) | |
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ROCHESTER GAS AND ELECTRIC CORPORATION o
89 EAST AVENUE, ROCHESTER, N.Y. 14604 KEITH W. AMISH SENIOR VICE PREEIDENT KKKCTRICAND 8TKAM Regu1atory File Cyo March 24, 1972 TEEEPHON K AREA cooE Tie 546-2700 Dr. Peter A. Morris, Director Division of Reactor Licensing U. S. Atomic Energy Commission 7920 Norfolk Avenue
- Bethesda, Maryland 20014
Subject:
Information on Main Steam Header Docket No. 50-244 License No. DPR-18
Dear Dr. Morris:
The following report on an improvement made to the Ginna facility secondary system safety and power operated relief valves is hereby submitted.
This information has previously been given orally to your Staff and the Division of Compliance.
At Ginna, each of the two steamlines are protected by four safety valves and one power operated relief valve.
The lines are 30 inches in diameter with a design pressure of 1085 psig and a design temperature of 600 F.
Pipe material is A155 GR C55 Class l.
Both the safety valves and the power operated relief valves are mounted perpendicular to the 30 inch line.
The eight main steam safety valves have a combined rated capability of 6, 580, 000 lbs. /hr.
Each power operated relief valve is rated at 380, 000 lbs. /hr.
On Friday afternoon, March 17, RG4E learned that a stress
- analysis, performed by Gilbert Associates, of the, main steamline safety valve nozzle interface revealed that an undesirable stress condition could exist when the safety valves actuated.
On Saturday, March 18, a temporary su ort to correct this problem was designed
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ROCHESTER GAS AND EL IC CORP.
DATE March 24, 1972 Dr. Peter A. Morris SHEET NO.
2 and by Sunday, 6:00 a.m., installation was complete.
No difficulty was anticipated with the power operated relief valves.
- However, on
- Thursday, March 23, Gilbert Associates performed a stress analysis of this pipe-nozzle interface which revealed stress conditions higher than acceptable.
Installation of supports similar to those used under the safety valves was complete by 8:00 p. m.
The attached sketches A and 8 indicate the valve-steamline configuration and the temporary support under the safety and power operated relief valves.
Administrative procedure provides for backing off the jacking bolts when the plant is cooled down, since the bolts are set for the operating condition.
It is planned to perform a permanent modification during our spring 1972 refueling shutdown and to remove the temporary modifi-cation.
At present,
- however, the permanent design has not been finalized.
The supports were conservatively sized for the downward reaction resulting from blowing safety valves.
Installation of the supports reduces the total circumferential and longitudinal stresses during blowing to acceptable values.
Very truly yours, Keith W. Ami Attachment xc:
James P. O'Reilly Director, Region I Division of Compliance
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