ML19290F108
| ML19290F108 | |
| Person / Time | |
|---|---|
| Site: | Humboldt Bay, Diablo Canyon |
| Issue date: | 03/07/1980 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Crane P PACIFIC GAS & ELECTRIC CO. |
| References | |
| NUDOCS 8003180111 | |
| Download: ML19290F108 (1) | |
Text
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/,,,#'o UNITED STATES
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NUCLEAR REGULATORY COMMISSION
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SUITE 202, WALNUT CREEK PLAZA WALNUT CREE K, CALIFORNIA 94596 March 7, 1980 Docket Nos. 50-133, 50-275 & 50-323 Pacific Gas and Electric Company 77 Beale Street San Francisco, California 94106 Attention:
Mr. Philip A. Crane, Jr.
Assistant general Counsel Gentlemen:
This Info mation Notice is provided as notification of a p '...tially significant matter.
It is expected that recipients will review the infonnation for possible applicability to their facilities.
No spe-cific action or response is requested at this time.
If further NRC evaluations indicate the need, an IE Circular or Bulletin will be issued to request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely, lI mcS$~ -
R. H. Engelken Director
Enclosures:
1.
IE Information Notice No. 80-08 2.
List of Recently Issued IE Information Notices cc w/ enclosures:
W. Barr, PG&E W. Raymond, PG&E R. Ramsay, PG&E, Diablo Canyon E. Weeks, PG&E, Humboldt Bay E. B. Langley, Jr.
800318"N
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SSINS: 6870 UNITED STATES Accession No.:
NUCLEAR REGULATORY COMMISSION 7912190689 0FFICE OF INSPECTION AND EtlFORCEMEtlT WA3HINGTON, D.C.
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March 7, 1980 b'd&J a
IE Information Notice flo. 80-08 THE STATES COMPANY SLIDIflG LINK ELECTRICAL TERMINAL BLOCK Description of Circumstances:
On July 19, 1979, the Consumers Power Company notified the Nuclear Regulatory Commission of a defect found in the sliding link electrical terminal block manufactured 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. When the screw is tightened it birds the link, spacer and bar together to make electrical connection.
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 fom 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 intemittent 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 Information Notice is provided to inform licensees of a potentially significant matter.
It is expected that recipients will review the informa-tion for applicability to their facilities.
No written response to this IE Information Notice is required.
However, the reporting 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.
Enclosure:
Graphic Display of Terminal Block
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IE Information Notice No. 80-08 Enclosure March 7, 1980 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 80-07 Pump Shaft Fatigue Cracking 2/29/80 All Light Water Reactor Facilities holder power reactor OLs and cps 80-06 Notification of Significant 2/27/80 All holders of Reactor Events OLs and to near term OL applicants 80-05 Chloride Contamination 2/8/80 All licensees of nuclear of Safety Related Piping power reactor facilities and applicants and holders of nuclear power reactor cps 80-04 BWR Fuel Exposure in 2/4/80 All BWR's holding a Excess of Limits power reactor OL or CP 80-03 Main Turbine Electro-1/31/80 All holders of power Hydraulic Control System reactor OLs and cps 80-02' 8X8P !!ater Rod Lower 1/25/80 All BWR Facilities End Plug Wear holder power reactor OLs or cps 80-01 Fuel Handling Events 1/4/80 All holders of power reactor OLs and cps 79-37 Cracking in Low Pressure 12/28/79 All power reactor OLs Turbine Discs and cps 79-36 Computer Code Defect in 12/31/79 All power reactor OLs Stress Analysis of Piping and cps Elbow 79-35 Control of Maintenance 12/31/79 All power reactor facilities and Essential Equipment with an OL or CP 79-34 Inadequate Design of 12/27/79 All holders of power reactor Safety-Related Heat OLs and cps Exchangers
ENCLOSURE 1 TO IE INFORMATION NOTICE 80 08 g r..,
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