ML19305C115
| ML19305C115 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 03/14/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Andognini G BOSTON EDISON CO. |
| References | |
| NUDOCS 8003260014 | |
| Download: ML19305C115 (1) | |
Text
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UNITED STATES Th g.
NUCLEAR REGULATORY COMMISSION g
REGION l 631 PARK AVENUE KING OF PRUSSIA, PENNSYLVANIA 19406 q
Docket No. 50-293 Boston Edison Company M/C Nuclear ATTN:
Mr. G. Carl Andognini, Manager Nuclear Operations Department 800 Boylston Street Boston, Massachusetts 02199 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, e
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:
P. J. McGuire, Pilgrim Station Manager 80032606/$
ENCLOSURE 1 SSINS NO. 6830 Accession No.:
1 UNITED STATES 7912190662 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Circular No. 80-04 Date:
March 14, 1980 Page 1 of 3 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:
I.
MAIN STEAM CHECK VALVE HEX NUT LOCKING DEVICES, TURKEY POINT NO. 3 REPORTABLE OCCURRENCE 250-79-31 (Oct. 22, 1979) l During a planned outage of Turkey Point Unit No. 3 on October 7, 1979, a i
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 valve was fully operable.
The 38 and 3C main steam check valves were 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 Scnutte and Koerting SK Type 828.
II.
SLIPPAGE AND MISALIGNMENT OF VALVE LINKAGES, DAVIS-BESSE LICENSEE EVENT REPORT NOS78-101 (Nov. 1, 1978),78-126 (Jan. 26, 1979),79-068 (July 19, 1979), and 79-098 (Oct. 30, 1979)
These reports involve the inoperability of two service water system valves and one component cooling water system valve.
The va declared inoperable because th missing or had loosened to the ment of the valve linkage.
Th DUPLICATE DOCUMENT The suppiter has provided the manual that defines the torque Entire document previously used to retain the actuator li entered into system under:
ANO N o.
of pages: