ML19305B154
| ML19305B154 | |
| Person / Time | |
|---|---|
| Site: | Pilgrim |
| Issue date: | 03/07/1980 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Andognini G BOSTON EDISON CO. |
| References | |
| NUDOCS 8003190237 | |
| Download: ML19305B154 (1) | |
Text
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UNITED STATES
,E NUCLEAR REGULATORY COMMISSION o
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REGION I 0,
g 631 PARK AVENUE D
KING OF PRUSSIA, PENNSYLVANIA 19406
- ,o q't March 7, 1980 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 Information Notice No. 80-08, The States Company Sliding Link Electrical Terminal Block, is forsarded to you for information.
No written response is required.
If you desire additional information regarding this matter, please contact this office.
Sincerely, d
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Boyce H. Grier j
Director
Enclosures:
1.
IE Information Notice No. 80-08 with Attachment 2.
List of Recently Issued IE Information Notices CONTACT:
S. D. Ebneter (215-337-5296) cc w/encls:
P. J. McGuire, Pilgrim Station Manager 800319o 2_5q,
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.=,g ENCLOSURE 1 SSINS: 6870 UNITED STATES Accession No.:
NUCLEAR REGULATORY COMMISSION 7912190689 0FFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 i
IE Information Notice No. 80-08 Date:
March 7, 1980 fage 1 of 1 THE STATES COMPANY SLIDING LINK ELECTRICAL TERMINAL BLOCK i
Description of Circumstances:
On July 19, 1979, the Consumers Power Company notified the Nuclear Regulatory Commicsion of a defect found in the sliding link electrical terminal block manue.jured by the States Company, a subsidiary of Multi Amp Corp.
The defective terminal blocks were found at the Midland plant.
The connection between the two slotted bars on the terminal block is made by a U-shaped sliding link and spacer located between the two bars.
The top of the U-shaped link and the spacer are drilled and the bottom of the link is threaded to accept a 8-32 screw.
wnen the screw is tightened it binds the link, spacer and bar together to make electrical connectio:
Loosening the screw and sliding the link from between the bars breaks the connection.
The purpose of the link is,to provide easy insertion of test instruments, etc. into the circuit!
The defect, which has been identified in 5% of the terminal blocks checked, occurs in the form of a crack between the threaded screwhole and the side of the U-shaped link. When the screw is tightened the crack widens and a poor or intermittent electrical connection can result.
A defective link is impossible to cinch tightly in place and is difficult to detect visually. shows the States Company terminal block.
The defect, a crack in the bottom portion of the metal U-shaped link, is displayed in the exploded view of the terminal block assembly.
These terminal blocks are widely used in the nuclear industry and may be used as permanent installations in safety related systems.
The defective mechanical connection can cause an electrical circuit malfunction.
This Irformation Notice is provided to inform licensees of a potentially significant matter.
It is expected that recipients will review the informa-tion for applicsoility to their facilities.
No written response to this IE Informatico Notice is required.
However, the repo. ting requirements as set forth in the regulations must be met.
If you require additional information regarding this matter, contact the Director of the appropriate NRC Regional Office.
Attachment:
' Graphic Display of Terminal g
l ENCLOSURE 2 IE Information Notice No. 80-08 Date:
March 7, 1980 Page 1 of 1 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject.
Date Issued to 1
Notice No.
Issued
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79-32 Separation of Electrical 12/21/79 All Power Reactor Faci-Cables for HPCI and ADS lities with an Operating License (0L) or Construction Permit (CP) 79-33 Improper Closure of Primary 12/21/79 All Power Reactor Faci-Containment Access Hatches lities with an OL or CP 79-34 Inadequate Design of Safety-12/31/79 All Power Reactor Faci-Related Heat Exchangers lities with an OL or CP 79-35 Csim:1 of Maintenance 12/31/79 All Power Reactor Faci-and Essential Equipment lities with an OL or CP 79-36 Computer Code Defect in 12/31/79 All Power Reactor Faci-Stress Analysis of Piping lities with an OL or CP Elbow 79-37 Cracking in Low Presssure 12/31/79 All Power Reactor Faci-Turbine Discs lities with an OL or CP 80-01 Fuel Handling Events 1/4/80 All Power Reactor Faci-lities with an OL or CP 80-02 8X8R Water Rod Lower 1/25/80 All BWR Facilities with End Plug Wear an OL or CP 80-03 Main Turbine Electro-1/31/80 All Power Reactor Faci-hydraulic Control System lities with an OL or CP 80-04 BWR Fuel Exposure in Excess 2/4/80 All BWR Facilities with of Limits an OL or CP 80-05 Chloride Contamination of 2/8/80 All Power Reactor Faci-Safety Related Piping and lities with an OL or CP Components and applicants for a CP 80-06 Notification of Signif-2/27/80 All Power Reactor Faci-icant Events lities with an OL and applicant for OL 80-07 Pump Fatigue Cracking 2/29/80 All Power Reactor Faci-lities with an OL or CP
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Attachment to IE Information Notice No. 80-08 ENCLOSURE 1 TO IE INFORMATION NOTICE 80-t i
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