ML19305C124
| ML19305C124 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 03/14/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Dunn C DUQUESNE LIGHT CO. |
| References | |
| NUDOCS 8003260026 | |
| Download: ML19305C124 (1) | |
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UNITED STATES 8
NUCLEAR REGULATORY COMMISSION o
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REGION l 0, [OV [
631 PARK AVENUE
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KING oP PRUSSIA, PENNSYLVANIA 19404 March 14, 1980 Docket No. 50-334 Duquesne Light Company ATTN:
Mr. C. N. Dunn Vice President Operations Division 435 Sixth Avenue Pittsburgh, Pennsylvania 15219 Gentlemen:
The enclosed IE Circular No. 80-04, " Securing of Threaded Locking Devices on Safety-Related Equipment," is forwarded to you for information.
No written response is required. If you desire additional information regarding this matter, please contact this office.
Sincerely, Off-..
/
Boyce H. Grier
- Director
Enclosures:
1.
IE Circular No. 80-04 2.
List of Recently Issued IE Circulars CONTACT:
L. E. Tripp (215-337-5232) cc w/encls:
F. Bissert, Technical Assistant Nuclear R. Washabaugh, QA Manager J. Werling, Station Superintendent G. Moore, General Superintendent, Power Stations Department J. J. Carey, Director of Nuclear Operations R. Martin, Nuclear Engineer J. Sieber, Superintencent of Licensing and Compliance, BVPS 80032600R6 1
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ENCLOSURE 1 SSINS NO. 6830 Accession No..
i UNITED STATES 7912190662 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555
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IE Circular No. 80-04 Date:
March 14, 1980 Page 1 of 3 i
SECURING OF THREADED LOCKING DEVICES ON SAFETY-RELATED EQUIPMENT Description of Circumstances:
In recent months, several licensee event reports have been submitted that address the inoperability of safety-related equipment caused by loosened threaded locking devices.
Some of the events are listed below:
MAIN STEAM CHECK VALVE HEX NUT LOCKING DEVICES, TURKEY POINT NO. 3
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I.
REPORTABLE OCCURRENCE 250-79-31 (Oct. 22, 1979)
During a planned outage of Turkey Point Unit No. 3 on October 7,1979, a two-inch internal diameter hex nut was discovered in the internals of a steam supply valve for a moisture separator-reheater.
Investigation revealed that the nut was missing from the disc stud of the 3A main steam check valve.
The disc and disc stud were in the proper position and the The 3B and 3C main steam check valves were valve was fully operable.
inspected and the disc stud, nut and locking washer were in place although some distress was noted on the 3C locking washer in that the tack welds on the locking pin had separated.
The licensee installed an improved locking device on the disc stud on each of the three main steam check valves. The locking device consists of a tab washer that is prevented from rotating by a pin and by fingers that extended on either side of the valve arm; the tabs are bent up against two faces of the hex nut. The main steam isolation valves (MSIV) have the same type of hex nut locking device.
The valves are Schutte and Koerting SK Type 828.
SLIPPAGE AND MISALIGNMENT OF VALVE LINKAGES, DAVIS-BESSE LICENSEE EVENT II.
REPORT NOS78-101 (Nov. 1, 1978),78-126 (Jan. 26, 1979),79-068 (July 19, 1979), and 79-098 (Oct. 30, 1979) two service water s tem These reports involve the inop valves and one component cooli declared inoperable because th l
missing or had loosened to the DUPLICATE DOCUMENT ment of the valve linkage. Th The supplier has provided the Entire document previously manual that defines the torque entered into system under:
used to retain the actuator li Q
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