ML19253A519
| ML19253A519 | |
| Person / Time | |
|---|---|
| Site: | Fort Calhoun  |
| Issue date: | 08/14/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Short T OMAHA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 7909100202 | |
| Download: ML19253A519 (1) | |
Text
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AR LINGToN, TE XAS 76012 August 14, 1979 Docket No.52-233 Omaha 5- - ' # - "over District ATIN:
- 2. I. Short, i=='erant General Manager 1623 Ea ey Street Omaha, Nebraska 68102 Gentlenen:
This IE Circular is provided as an early notification of a possible significart matter.
It is expected that recipients will review the information for pos-mole applicability to their facilities. No specific action or response is requested at this tice.
If further NRC evaluations so indicate, an IE Bulletin will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
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Sincerely f
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Karl V. Seyfri Director
Enclosures:
1.
IE Circular No. 79-17 2.
List of IE Circulars Issued in the Last 6 Months cc:
R. L. Andrews, Manager Fort Calhoun Station Post Office Box 98 Fort Calhoun, Nebraska 68102 S,'3,bOUY D@@]D O d JU 2@
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UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 IE Circular No. 79-17 Date: August 14, I??9 Page 1 of 1 CONTACT PROBLEM IN SB-12 SWITCHES ON GENERAL ELECTRIC METALCLAD CIRCUIT BREAKERS The General Electric Company, Swit hgear Department in Philadelphia, reported to the NRC on July 3, 1979, an intermittent contact problem in SB-12 switches.
This intermittent contact problem will cause a lack of continuity through the
a" contact of the switch that is used to energize the trip coil of the circuit breaker.
Investigation disclosed that a die used to form a hole in the contact arms of the switch had worn, resulting in elongated holes. This condition could permit the contact bridge member to move laterally relative to the contact arm, occasionally resulting in improper "a" contact wipe.
The worn die has been corrected, and all switches shipped on or after J"iy 1, 1979, include this correction. A review of the history of these components indicates that switches shipped in the time period of August 1, 1978 to July 1, 1979, could have this problem. The trip coil and auxiliary switch portion of the trip circuit is monitored for continuity by a red light on the front door of the switchgear.
This light is lit when the breaker is closed and the control circuits are energized.
If the red light is lit, this indicates that the "a" contacts of the switch are closed, and that a trip signal will trip the breaker.
Based on the above, the licensees are ai ised to do the following:
1.
Insure that all General Electric Company Metalclad Circuit Breakers shipped to your facilities during the period from August 1, 1978 to July 1, 1979 and used in or affecting the operation of safety related equipment are furnished with new SB-12 control switches as promptly as possible.
2.
Pending replacement of SB-12 control switches, administrative controls should be initiated to assure the red light which demonstrates contact continuit), is lit and remains lit each time these circuit breakers are closed.
No written response to this circular is required.
If you require additional information regarding this subject, contact the Director of the appropriate NRC Regional Office.
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IE Circular No. 79-17 August 14, 1979 LISTING OF IE CIRCULARS ISSUED IN LAST SIX MONTHS Circular Subject Date of Issued To No.
Issue 79-03 Inadequate Guard 2/23/79 All Holders of and Training - Qualifica-applicants for Special tion and Falsified Nuclear Material Licenses Training Records in Safeguards Group I 79-04 Loose Locking Nut 3/16/79 All Holders of Reactor On Limitorque Valve Operating License (OL) or Operators Construction Permits (CP) 79-05 Moisture Leakage in 3/20/79 All Holders of Reactor Stranded Wire Conductors Operating License (OL) or Construction Permits (CP) 79-06 Failure to Use Syringe 4/19/79 All Holders of Medical and Battle Shields in Licensees except Teletherapy Nuclear Medicine Licensees 7.*-0 7 Unexpected Speed Increase 5/2/79 All Holders of BWR Operating of Reactor Recirculation Licenses (OLs) or Construc-MG Set Resulted in Reactor tion Permits (cps)
Power Increase 79-08 Attempted Extortion - Low 5/18/79 All Fuel Facilities and Enriched Uranium Reactors Licensed by NRC 79-09 Occurrences of Split or 6/22/79 All Materials Priority I, Punctured Regulator Fuel Cycle and Operating Diaphragms in Certain Reactor Licenses (OL)
Self Contained Breathing Apparatus 79-10 Pipefittings Manufactured 6/26/79 All Power Reactor Licensees from Unacceptable Material with a Construction Permit and/or Operating License (OL) 79-11 Design / Construction 6/27/79 All Holders of and Applicants Interface Problem for Power Reactor Construction Permits (CP)
Enclosure Page 1 of 2
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IE Circular No. 79-17 August 14, 1979 79-12 Potential Diesel Generator 6/28/79 All Power Reactor Licensee with Turbocharger Problem a Construction Permit (CP) and/or Operating License (OL) 79-13 Replacement of Diesel 7/13/79 All Power Reactor Licensee Fire Pump Starting with a Construction Permit Contactors (CP) and/or Operating Licensee (OL) 79-14 Unauthorized Procurement 7/13/79 All Medical Licensees and Distribution of Except Teletheraphy XE-133 Medical Licensees and to all Radiopharmaceutical Suppliers 79-15 Bursting of High Pressure 8/8/79 All Materials Priority I, Hose and Malfunction of Fuel Cycle and Operating Relief Valve "O Ring in Power Reactor Licensees Certain Self-contained Breathing Apparatus 79-16 Excessive Radiation 8/16/79 All Radiography Exposures to Members Licensees of the General Public and a Radiographer Enclosure Page 2 of 2 v u o >./ f) o 'i' n~