ML20209F293
| ML20209F293 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 04/27/1987 |
| From: | Jerrica Johnson SOR, INC. (STATIC O-RING) |
| To: | NRC |
| References | |
| REF-PT21-87, REF-PT21-87-095-000 IEIN-87-016, IEIN-87-16, PT21-87-095-000, PT21-87-95, NUDOCS 8704300252 | |
| Download: ML20209F293 (1) | |
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a SOR, INC.
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April 27,1987 To: All Nuclear Power Plant Qualified Pressure Switch Users
'Re:
Preliminary 10CFR PART 21 Notice SOR is investigating a potential problem with our gauge pressure switches.
We direct your attention to NRC Information Notice IN 87-16.
This notice addresses the SOR Series 1, 4, 5, 6, 8, 9,12 and 54 switches.
t We - have discovered several switches at Davis-Besse Nuclear Generating Station which have contained 'a gas bubble _ formation between the diaphragm layers within the sensing element of the switches.
The cause of the problem has not yet been isolated. The use of 316 stainless steel diaphragms has not completely eliminated the bubble formation as previously concluded in IN87-16.
An indicator of a bubble formation is the increase in deadband of the pressure switch (i.e.: the rise of the increasing set point and/or the fall of the decreasing set point).
The formation of the bubble may cause the set point to shift outside the technical specification limits.
SOR continues to investigate the phenomena.
For any questions, please contact the factory.at (913) 764-2630, and ask for Nuclear Sales.
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'Regards: 1 i
e JYi *. lO'L"Uv\\)Jh,x James R. Jo'hnsdn Vic6 Presideng General Manager N.
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