ML19249B964
| ML19249B964 | |
| Person / Time | |
|---|---|
| Site: | Yankee Rowe |
| Issue date: | 08/14/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Groce R YANKEE ATOMIC ELECTRIC CO. |
| References | |
| NUDOCS 7909070155 | |
| Download: ML19249B964 (1) | |
Text
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Docket No. 50-29 AUG 1.: 1973 Yankee Atomic Electric Company ATTN:
Mr. Robert H. Groce Licensing Engineer 20 Turnpike Road Westborough, Massachusetts 01581 Gentlemen-This Circular is provided as an early notification of a possible significant matter.
It is expected that recipients wi'l review the information for pos-sible applicability to their facilities.
No specific action cr response is requested at this time.
If further NRC evaluations so indicate, an IE Bul-letin will be issued to recommend or request specific licensee actions.
If you have qu itions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely,
/!'
d 414oyce H. Grier Director
Enclosures:
1.
IE Circular No. 79-17 2.
List of IE Circulars Issued in the Last 6 Months cc wiencls:
H. Autio, Plant Superintendent L. E. Minnick, President 7 909 07c>/5 s j
ENCLOSURE 1 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
205f5 IE Circular No. 79-17 Date:
August 14, 1979
. age 1 of 1 CONTACT PROBLEM IN 58-12 SWITCHES ON GENERAL ELECTRIC METALCLAD CIRCUIT BREAKERS The General Electric Company, Switchgear Department in Philadelphia, reported to the NRC on July 3, 1979, an intermittent contact problem in 58-12 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 correctad, 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 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 indicater 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 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 initated to assure the red light which demonstrates contact continuity, 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.
9
ENCLOSURE 2 IE Circular No. 79-17 Date:
August 14, 1979 Page 1 of 2 LISTING OF IE CIRCULARS ISSUED IN LAST SIX MONTHS Circular Subject First Date Issued To No.
of Issue 79-03 Inadequate Guard 2/23/79 All Holoers of and Training / Qualification Applicants for and Falsified Training Special Nuclear Records Material Licenses in Safeguards Group I 79-04 Loose Locking Nut on 3/16/79 All Power Reactor Limitorque Valve Facilities wi' an Operators OL or CP 79-05 Moisture Leakage in 3/20/79 All Power Reactor Stranded Wire Facilities with an Conductors OL or CP 79-06 Failure to Use Syringe 4/19/79 All Holders of and Bottle Shields in Medical Licenses Nuclear Medicine Except Teletho opy Licenses 79-07 Unexpected Speed 5/2/79 All BWR Power Reactor Increase of Reactor Facilities with an Recirculation MG Set OL or CP Resulted in Reactor Power Increase 79-08 Attempted Extortion-5/18/79 All Fuel Facilities Low Enriched Uranium and Licensed Reactors 79-09 Occurrences of Split 6/22/79 All Materials Priority t
or Punctured Regulator I, Fuel Cycle and Diaphragms in Certain Operating Reactor Sel f-Contained Licensees Breathing Apparatus 07"
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2 IE Circular No. 79-17 Date:
August 14, 1979 Page 2 of 2 LISTING OF IE CIRCULARS ISSUED IN LAST SIX MONTHS Circular Subject First Date Issued to No.
of Issue 79-10 Pipefittings Manu-6/26/79 All Power Reactor factured from Facilities with an Unacr: stable Material OL or CP 79-11 Design / Construction 6/27/79 All Applicants for, Interface Problem and Holders of cps 79-12 Potential Diesel 6/28/79 All Power Reactor Generator Turbo-Facilities with an charger Problem OL or CP 79-13 Replacement of Diesel 7/16/79 All Power Reactor Fira Pump Startina Facilities with an Contactors OL or CP 79-14 Unauthorized Procure-7/16/79 All Medical Licensees ment and Distribution except Teletherapy Medi-of Xenon-133 c 1 Licensees, and all Licensed Radiopharma-ceutical Suppliers 79-15 Bursting of High Pres-8/8/79 All Materials Priority sure Hose and Malfunc-I, Fuel Cycle and Opera-tion of Relief Valve "0" ting Power Reactor Ring in Certain Self-Licensees Contained Breathing Apparatus 79-16 Excessive Radiation 8/16/79 All Radiography Exposures to Members Licensees Of The General Public And A Radiographer (j b U E'