ML20209F980
| ML20209F980 | |
| Person / Time | |
|---|---|
| Site: | Nine Mile Point  |
| Issue date: | 04/16/1987 |
| From: | Swanson N NAMCO CONTROLS |
| To: | Zech G NRC |
| Shared Package | |
| ML20209F986 | List: |
| References | |
| REF-PT21-87, REF-PT21-87-079-000 PT21-87-079-000, PT21-87-79, NUDOCS 8704300440 | |
| Download: ML20209F980 (1) | |
Text
s.
e Namco Controls 7567 Tyler Boulevird Mentor, Ohio 44060 (216) 946-9900 Telex 241566 g g g g gn.==.
April 16, 1987 secause nouung wse worms berra 07 dS b Mr. Gary Zech Chief - Vendor Program U. S. Nuclear Regulator Commission Washington, DC 20555
Subject:
Our letter of July 14, 1986 (Copy attached)
Dear Mr. Zech:
All three items listed on page one of the subject letter have been completed, as follows:
- 1) Replacement lever arms were promptly provided to Niagara Mohawk.
- 2) The cracked lever arm returned from Nine Mile Point was placed on life test, and operated in excess of 600,000 cycles before failure.
(The switch qualified life is 100,000 cycles.)
3) a) The material used in the lever arm returned from Niagara Mohawk is Premix 3000-15.
The material in our present production switches is Rogers RX 865.
Material specifications indicate strength characteristics of these two materials to be virtually equivalent.
b) The riveting process has been examined and modified as necessary to insure against any overstressing of the part.
c)
Q.C.
inspectors and assembly operators have been cautioned to examine these parts closely for any indication of cracking in the vicinity of the rivets.
On the basis of the above information, and because our production inspection re-cords show only 16 parts rejected for this condition over the past five years, and because we have had no other field problems attributable to this condition from a total of 54,600 switches shipped since 1979, we consider the instant case to be an anomoly, and we recommend the matter be closed.
We trust you will agree with this recommendation, and remain Very /
tr y yours, 8704300440 870416 PDR ADOCK 05000220 ge PDR N. E. Swanson President NES/kg
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cc: J. DiGiacomo D. Jackson III
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B. Kovarik E. Roob Official Copy C. F. Crocker, Stone & Webster, Lycoming, NY J. F. Hawkins, Stone & Webster, Boston, MA 4~ acw cmn.~o c-w