ML20209F980

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Informs That All Three Items on Page 1 of Encl Completed,Including Replacement Lever Arms for Util,Life Test for Cracked Lever Arm & Exam of Riveting Process to Ensure Against Overstressing.Recommends Matter Be Closed
ML20209F980
Person / Time
Site: Nine Mile Point  Constellation icon.png
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 g g g g gn .==. Telex 241566 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 tr y yours, Very /

8704300440 870416 PDR ADOCK 05000220 ge _

$ PDR N. E. Swanson President NES/kg

'l$

cc: J. DiGiacomo D. Jackson III \

B. Kovarik E. Roob . .

C. F. Crocker, Stone & Webster, Lycoming, NY Official Copy J. F. Hawkins, Stone & Webster, Boston, MA 4~ acw cmn.~o c-w