ML19305B146
| ML19305B146 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 03/07/1980 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | William Jones OMAHA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 8003190225 | |
| Download: ML19305B146 (1) | |
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CENTRAL FILES UNITED STATES PDR:HQ
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NUCLEAR REGULATORY COMMISSION LPDR 1
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States March 7, 1980 Docket No.
50-285 Omaha Public Power District ATTN:
W. C. Jones, Division Manager -
Production Operations 23 Harney Street Omaha, Nebraska 68102 Gentlemen:
This IE Infor=ation Notice is provided as notification of a potentially significant matter.
It is expected that recipients will review the information for possible applicability to their facilities. No specific 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 Off. ice.
Sincerely, f
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Director
Enclosures:
1.
IE Information Notice No. 80-08 2.
List of Recently Issued IE Information Notices cc:
S. C. Stevens, Manager Fort Calhoun Station Post Office Box 98 Fort Calhoun, Nebraska 68102 2
8003190
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SSINS: 6870 UNITED STATES Accession No.:
NUCLEAR REGULATORY COMMISSION 7912190689 0FFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Information Notice No. 80-08 Date: March 7, 1980 Page 1 of 1
'IHE STATES COMPANY SLIDING 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 Comp.iny, a subsidiary of Multi Amp Corp. The defective terminal blocks were found at the Midland plant.
The connection between the two sletted 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 binds 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 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.
Enclosure I 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 i
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.
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Enclosure:
Graphic Display of Terminal Block
IE Information Notice No. 80-09 March 7, 1980 LISTING OF RECENTLY ISSUED IE INFORMATION NOTICES Info rmation Subject Date Issued To Notice.No.
Issued 80-02 8X8R Water Rod Lower 1/25/80 All BWR Facilities End Plug Wear holder of power reactor Operating Licenses (OLs)
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or Construction Permits (cps) 80-03 Main Turbine Electro-1/31/80 All holders of power Hydraulic Control System reactor Operating Licenses (OLs) and Construction Permits (cps) 80-04 BWR Fuel Exposure in 2/4/80 All BWR's holding a Excess of Limits power reactor Operatin2 License (OL) or Construction Permit (CP) 80-05' Chloride Contamination 2/8/80 All licensees of nuclear of Safety Related Piping power reactor facilities and Components and applicants and holders of nuclear power reactor Construction Permit (CP) 80-06 Notification of Significant 2/27/80 All holders of Reactor Events Operating Licenses (0Ls) and to near term Operating Licenses (0L) applicants 80-07 Pump Shaft Fatigue Cracking 2/29/80 All Ligtit Water Reactor Facilities holder power reactor Operating Licenses (OLs) and Construction Permits (cps) 80-08 The States Company Sliding 3/7/80 All power reactor Link Electrical Terminal facilities with an Operating License (OL) or a Construction Permit Enclosure
ENCLOSURE 1 TO IE INFORMATION NOTICE 80-08 1 -
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4hhlil#$4 Side View of States Company Terminal Block in Assembled Position i
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Exploded View of States Company Terminal Block