ML19323F618
| ML19323F618 | |
| Person / Time | |
|---|---|
| Site: | Maine Yankee |
| Issue date: | 05/14/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Groce R Maine Yankee |
| References | |
| NUDOCS 8005290237 | |
| Download: ML19323F618 (1) | |
Text
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4 M8NG OF PRUS$1A, PENNSYLVANIA 19404 May 14, 1980 Docket No. 50-309 Maine Yankee Atomic Power Company ATTN:
Mr. Robert H. Groce Senior Engineer - Licensing 25 Research Drive Westborough, Massachusetts 01581 Gentlemen:
The enclosed IE Circular No. 80-12, " Valve-Shaft-To-Actuator Key May Fall Out of Place When Mounted Below Horizontal Axis," is forwarded to you for infor-mation.
No written response is required.
If you desire additional infor-mation regarding this matter, please contact this office.
Sincerely,
=
oyce H. Grier Director
Enclosures:
1.
IE Circular No. 80-12 with Attachments 2.
List of Recently Issued IE Circulars CONTACT:
D. L. Caphton (215-337-5346) cc w/encls:
E. Wood, Plant Superintendent E. W. Thurlow, President l
l l
8005290237
ENCLOSURE 1 l
l SSINS No.: 6830 UNITED STATES Accession No.:
NUCLEAR REGULATORY COMMISSION 8005050052 0FFICE OF INSPECTION AND ENFORCEMENT i
WASHINGTON, D.C.
20555 IE Circular No. 80-12 Date:
May 14, 1980 Page 1 of 2 VALVE-SHAFT-TO-ACTUATOR KEY MAY FALL OUT OF PLACE WHEN MOUNTED BELOW HORIZONTAL AXIS Description of Circumstances:
l Tennessee Valley Authority has identified and reported to the NRC a non-conformance on a Bettis Robot-Arm actuator installed on a Pratt butterfly valve at the Sequoyah nuclear plant.
It is reported (ref. attached 10 CFR 50.55(e) report) that a valve became inoperable when_the valve-shaft-to-actuator key fell out of place.
It is further noted that the orientation of this valve assembly was such that the operator was on the bottom of the valve (below the horizontal axis).
The Pratt butterfly valve furnished with Bettis actuator is designed with a press-fit keyway connection valve / actuator.
We believe other manufacturers' connections may be of similar construction and therefore subject to this failure mode.
On May 1,1980, Pratt Company sent letters to their customers who have these connections (attached list). They recommended that their customers review their installation of such connections, and if the keyway is oriented below horizontal, make one of the following field modifications:
1.
Add a spacer bushing, or shim plate to fill the void between the top of the shaft and the indicating plate on the actuator.
2.
Locally upset the end of the valve shaft in the area of the keyway using a hand punch in such a way that the key could not work loose.
3.
Install new keys of longer length which extend above the end of the valve shaft whereby the key is up to the actuator plate and could not slip down if inverted.
Recommended Action for Licensee Consideration:
We request that all plants make the connections similar to the above des DUPLICATE DOCUMENT not supplied by those particular na are susceptible to failure, one of t Entire document previously appropriate action should be taken entered into system tuader:
xNo BooSoCo063 No. of pages:
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