ML19323F627
| ML19323F627 | |
| Person / Time | |
|---|---|
| Site: | Fort Saint Vrain  |
| Issue date: | 05/14/1980 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Millen C PUBLIC SERVICE CO. OF COLORADO |
| References | |
| NUDOCS 8005290247 | |
| Download: ML19323F627 (1) | |
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NUCLEAR REGULATORY COMMISSION LPDR
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May 14, 1980
,,e STATE Dockst No. 50-267 Public Service Company of Colorado ATTN:
Mr. C. K. Millen Senior Vice President P. O. Box 840 Denver, Colorado 80201 Gentlemen:
i The enclosed IE Circular No. 80-12, is forwarded to you for information.
If there are any questions related to your understanding of the suggested actions, please contact this office.
Sincerely, O,
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M,y1-Karl V. Seyfrit
$ ',I Director
Enclosures:
1.
IE Circular No. 80-12 2.
List of Recently Issued IE Circulars cc:
D. W. Warembourg, Nuclear Production Manager Fort St. Vrain Nuclear Station P. O. Box 368 Platteville, Colorado 80651 L. Brey, Manager, Quality Assurance l
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ENCLOSURE 1 SSINS No.: 6830 UNITED STATES Accession No.:
NUCLEAR REGULATORY COMMISSION 8005050052 0FFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Circular No. 80-12 Date:
May 14, 1980 Page 2. of 2 VALVE-SHAFT-TO-ACTUATOR KEY MAY FALL OUT OF PLACE WHEN MOUNTED BELOW HORIZONTAL AXIS l
Description of Circumstances:
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 imted 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:
i We request that all plants make the connections similar to the above des DUPLICATE DOCUMENT not supplied by those particular ma are susceptible to failure, one of t Entire document previously appropriate action should be taken t entered into system under:
ANO hh b
No. of pages:
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