ML20082Q618
| ML20082Q618 | |
| Person / Time | |
|---|---|
| Site: | Byron, Braidwood, 05000000 |
| Issue date: | 12/02/1983 |
| From: | Tramm T COMMONWEALTH EDISON CO. |
| To: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| References | |
| 10CFR-050.55E, 10CFR-50.55E, 7701N, NUDOCS 8312120282 | |
| Download: ML20082Q618 (2) | |
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AM8 Commonwealth Edison
) One First National Plaza, Chicago Ilknois O ] Chicago, lihnois 60690 Address Reply to: Post Office Box 767 (j
December 2, 1983 Mr. James G. Keppler Regional Administrator U.S. Nuclear Regulatory Commission 799 Roosevelt Road Glen Ellyn, IL 60137
Subject:
Byron Generating Station Units 1 and 2 Braidwood Generating Station Units 1 and 2 Pacific Scientific Snubber Capstan Springs NRC Docket Nos. 50-454, 50-455, 50-456, and 50-457 Dear' Mr. Keppler On October 28, 1983 Commonwealth Edison notified Mr. R. C. Knap of a deficiency reportable pursuant to 10 CFR 50.55(e) regarding capstan springs in Pacific Scientific snubbers being installed at Byron and Braidwood stations.
This letter fulfills the thirty day reporting requirement of the regulation.
For your tracking purposes this deficiency has been assigned number 83-13 for Byron and 83-15 for Braidwood.
Description of Deficiency We have been informed by ITT-Grinnell that Pacific Scientific Corporation has identified a potential problem with capstan springs in some of their mechanical snubbers.
Certain model PSA-1 and PSA-3 snubbers were supplied with capstan springs of a type that experi-enced premature failure in dynamic testing.
Preliminary analyses indicates that the failures are associated with metallurgical defects introduced during manufacture of the springs.
The springs could fall during a seismic event.
Analysis of Safety Implications Failure of the capstan spring could release fragments which might cause snubber binding or lockup.
Failure of this spring could also prevent snubber lockup.
Either failure mode could result in increased piping movements and loads during a seismic event.
The safety implications of such a snubber failure can only be established with detailed piping analysis, consideration of the ultimate pipe strength, and evaluation of the effectiveness of the available redundancy and diversity in plant safety equipment.
D N,6 M 8312120282 831202 PDR ADDCK 05000454 s
PDR DZ__iD___-__-_a
.A.
J. G. Keppler December 2, 1983 Corrective-Action Potentially defective snubbers will be replaced or inspected and repaired as necessary to support our fuel load schedules.
Please address further questions regarding this matter to this Very truly yours, hke W
T. R.
Tramm Nuclear Licensing Administrator im cc:
Director of Inspection and Enforcement NRC Resident Inspector - Byron NRC Resident Inspector - Braidwood i
7701N 8
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