ML20032E708
| ML20032E708 | |
| Person / Time | |
|---|---|
| Site: | McGuire, Mcguire  |
| Issue date: | 11/10/1981 |
| From: | Hollander T PRESRAY CORP. (SUBS. OF PAWLING RUBBER CORP.) |
| To: | NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| References | |
| REF-PT21-81-517-000 PT21-81-517, PT21-81-517-000, NUDOCS 8111200833 | |
| Download: ML20032E708 (2) | |
Text
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PAWLING, NEW YORK 12564 (914) 855-1220 November 10, 1981 (9
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'lj'7 NOVl 91981*':E Office of Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington, DC 26555
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Subject:
Airlock Door Seals 4 j McGuire Nuclear Station W
Reference:
Presrd7 File 17376 An outline covering our investigation, analysis, and proposed corrective action relative to the failed seal follows:
I.
Visual and microscopic examination of the failed seals revealed axial cracking in the corner radius of the seal inner air tube chamber.
It has been concluded that cracks are the results of wrinkles, fo?ds and laps pro-duced during the seal manufacturing process.
The inner tube was extruded in a circular form and is pressed into a flat oval shape during the seal construction and while the tube material is in the uncured state.
In the process of rearranging the geometry of the seal from a circular to an oval shape, wrinkles, folds and laps are produced in the circular corners of the oval shape.
The uncured tube mat-erial is plastic and therefore these imperfections are stabilized as permanent defects or stress risers during the final seal curing process.
II.
The resolution of this problem is to extrude the inner tube in a flat oval shape and cure the inner tube prior to seal construction.
This process eliminates the excess material (the cause of the defects) due to rearranging the geo-metry and stabilizes the corner radius during the seal con-struction and curing process.
Test seals have been produced, tested and inspected to verify that the above resolution has eliminated the defects and that the seal performs in accordance with the original specifications.
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8111200833 811110 PDR ADOCK 05000369 S
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'h Director Office of Inspection and Enforcement November 10, 1981 U.S.
Nuclear Regulatory Commission III.
In order to verify that future seals are manufactured correctly and without these defects, our customer, the W.J. Woolley Company, will select at random one seal from every twenty seals manufactured to dissect and perform detailed inspection.
IV.
To date, the McGuire unit is the only plant with this seal design in operation.
We have requested from the W.J.
Woolley Company a list of all installations of this seal design. Upon review of this list and projected seal operation schedule, a program will be established to assure that only seals void of these defects will be used for plant operation.
Sincerely, PRESRAY M
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Th6odore C. Hollander, J r,
- Executive Vice President TCH:alv cc: Mr. Dwaine A. Godfrey W.
J. Woolley Company cc:
R.A.
Schroth P. Orwick W.
Gambino THE PRESR AY CORPOR ATION / SUB SIDI ARY OF P AWLING RU BOER CO RPOR ATION t
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