ML19249B898
| ML19249B898 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 08/14/1979 |
| From: | Engelken R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V) |
| To: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| References | |
| NUDOCS 7909070056 | |
| Download: ML19249B898 (1) | |
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UNITED STATES f.
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1990 N. C ALIFO R NI A JOULEVARD
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SUITE 202, WALNUT CREE K PLAZA WALNUT CREE K, CALIFORNI A 94L94 August 14, 1979 Docket tio. 50-312 Sacramento Municipal Utility Listrict P. O. Box 15830 Sacramento. California 95813 Attention: Mr. John J. Mattinoe
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Assistant General fianager Gentl enen:
This Circular is provided as an early notification of a.possible significant matter.
It is expected that recipients will review the information for possible applicability to their facilities.
?!o specific action or response is requested at this time.
If further I;RC evaluations so indicate, an IE Culletin will be issued to recommend or request specific licensee actions.
If you have questions regarding this matter, please contact the Director of the appropriate f!RC Regional Office.
Sincerely,
'nar pt R. H. Engelken Director
Enclosures:
1.
IE Circular f40. 79-17 2.
List of IE Circulars Issued in Last Six Months cc w/encls.
R. J. Rodriguez, SMUD L. G. Schwieger, SMUD 4
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Accession tio:
7908090272 SSIt;S:
6830 UNITED STATES
?!UCLEAR REGULATORY CGro1ISSIOfl 0FFICE OF INSPECTION A!;D Et FORCEttENT WASHINGTON, D.C.
20555 August 14, 1979 IE Circular tio. 79-17 CONTACT PROBLEit IN SB-12 SWITCHES Ott GENERAL ELECTRIC fiETALCLAD CIRCUIT
??.EME7.5 The General Electric Company, Switchgear Department in Philadelphia, reported to the flRC on July 3,1979, an intemittent 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 improgr "a" contact wipe. The worn die has been corrected, and all switches shipped on or after July 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 problen.
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 indical.es 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 advised to do the following:
1.
Insure that all General Electric Company Metelclad 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 initated to assure the red light which denonstrates contact continuity, is lit and remains lit each time these circuit breakers are closed, flo written response to this circular is required.
If you require additional information regarding this subject, contact the Director of the appropriate flRC Regional Office.
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IE Circular f:o. 79-17 Enclosure August 14, 1979 Page 1 of 2 LISTIf!G OF IE CIRCULARS ISSUED IN LAST SIX fiONTHS Ci re t.' a r Subject Date of Issued to No.
Issue 79-03 Inadequate Guard Training-2/23/79 All Holders of Qualification and Falsified and applicants Training Records for Special fluclear fiaterial Licenses in Safeguards Group I 79-04 Loose Locking f:ut On
~3/16/79 All Holders of Limitorque Valve Reactor OLs or cps Operators 79-05 Moisture Leakage In 3/20/79
. All Holders of Stranded Wire Conductors Reactor OLs or cps 79-06 Failure to Use Syringe 4/19/79 All Holders of and Battle Shields in fledical Licensees Nuclear l'edicir.e except teletherapy licensees 79-07 Unexpected Speed Increase 5/2/79 All Holders of of Reactor Recirculation BWR OL's or CP's f1G Set Resulted in Reactor Power Increase 79-0P Attempted Extortion - Low 5/18/79 All Fuel Facilities Enriched Uraniun Licensed by fiRC 79-09 Occurrences of Split or 6/22/79 All Materials Punctured Regulator Diaphragms Priority I, Fuel In Certain Self Contained Cycle and Operating Breathing Apparatus Reactor Licensees 79-10 Pipefittings Manufactured 6/26/79 All Power Reactor from Unacceptable flaterial Licensees with a CP and/or OL 79-11 Design / Construction 6/27/79 All Applicants Interface Problem for, and Holders of Power Reactor cps t
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IE Circular No. 79-17 Enclosure August 14, 1979 Page 2 of 2 LISTING OF IE CIRCULAPS ISSUED IN LAST SIX MONTHS Circular Subject Date of Issued to No.
Issued 79-12 Potential Disel Generato-6/28/79 All Power Reactors Turbocharger Problen Operating Fecilities and all Utilities having a CP 79-13 Replacement of Diesel 7/10/79 All Power Reactor Fire Pump Starting Operating Facilities Contactors and all Utilities haviag a CP 79-14 Unauthorized Procurenent and
'7/13/79 All Medical Licensees Distribution of XE-133
- except Teletheraphy Medical Licensees and to all Radiopharmaceu-tical Suppliers 79-15 Bursting of High Pressure Pose 8/8/79 All Materials Priority I, and Malfuncticn of Relief Fuel Cycle and Operating Valve "0" Ring in Certain Self-Power Reactor Licensees Contained Breathing Apparatus 79-16 Excessive Radiation Exr.osures 8/16/79 All Radiography To Merbers Of The Gerseral Public Licensees And A Radiographer
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