ML19305D769
| ML19305D769 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 03/31/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Mary Johnson SOUTH CAROLINA ELECTRIC & GAS CO. |
| References | |
| NUDOCS 8004150495 | |
| Download: ML19305D769 (2) | |
Text
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UNITED STATES 8
NUCLEAR REGULATORY COMMISSION o
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101 MARIETTA ST N.W., SUITE 3100 g
o ATLANTA, GEORGIA 30303 MAR 311980 In Reply Refer To:
RII:JP0 GO-39p South Carolina Electric and Gas Company Attn:
M. C. Johnson, Vice President Special Services and Purchasing P. O. Box 764 Columbia, SC 29218 Gentlemen:
This Information Notice is provided a: a notification of a possibly significant matter.
It is expected that recipients will review the infor-mation for possible applicability to their facilities. No specific action or response is requested at this time.
If further NRC evaluations so indi-cate, an IE Circular or 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.
Sincerely, N
qq James P. O'Reilly Director
Enclosures:
1.
IE Information Notice No. 80-12 2.
List of IE Information Notices Recently Issued dCf 8004150 i
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MAR 311980 t
South Carolina Electric and Gas Company
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T. B. Conners, Jr.
Conners, Moore and Corber 1747 Pennsylvania Avenue, N.W.
Washington, D.C.
20006 A. A. Smith Quality Assurance Post Office Box 8 Jenkinsville, South Carolina 29065 O. S. Bradham, Manager Nuclear Operations Post Office Box 8 Jenkinsville, South Carolina 29065 t
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SSINS No.: 6870 Accession No.:
UNITED STATES 8002280654 NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 March 31, 1980 IE Information Notice No.: 80-12 i
INSTRUMENT FAILURE CAUSES OPENING OF PORV AND BLOCK VALVE i
Description of Circumstances:
On August 13, 1979, during full, steady-state power operation at the Connecticut Yankee Haddam Neck Plant, the pressurizer power operated relief valve (PORV) and its isolation (block) valve opened as a result of failure of i
a light source in the sigma bistable of the pressurizer pressure controller.
The failure of the light source was equivalent in control system response to an overpressure condition in the pressurizer. By system design both PORV and block valves are closed during normal operation and therefore both valves are required to open in response to an overpressure condition. The opening of the PORV and block valve allowed the pressurizer pressure to drop from its normal l
value of 2000 psig to 1950 psig before the PORV and block valves could be i
closed. The operator immediately overrode the open signal to the valves and
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closed the valves to stop depressurization. The pressurizer pressure then immediately returned to normal.
l The light source was subsequently replaced in the bistable and the pressure control system was returned to normal.
The licensee reported that failures of light sources in the bistable of this
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pressure controller and in other similar plant bistables had been experienced previously. Also, subsequently on February 4, 1980, a spurious signal from the pressure controller caused both PORV and block valve to open.
In both events, the operator responded immediately and effectively to limit the conse-l quences of the event to a relatively mild pressure transient on the reactor coolant system. The licensee also indicated that it had changed out the type
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of bistable with a solid state design which does not depend on a light source i
and which is expected to be more reliable.
i This information is provided as notification of a possibly significant matter.
It is expected that receipients will review the information for possible applicability to their facilities. No specific action or response is requested at this time.
If you have questions regarding this matter, please contact the Director of the appropriate NRC Regional Office.
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i IE Information Notice No. 80-12 Enclosure March 31, 1980 RECENTLY ISSUED IE INFORMATION NOTICES Information Subject Date Issued To Notice No.
Issued 80-12 Instrument Failure Causes 3/31/80 All power reactor Opening of PORV and Block Facilities Holding OLs Valve and cps 80-11 General Problems with ASCO 3/14/80 All holders of Reactor Valves in Nuclear Application OL, CP, fuel fabrica-Including Fire Protection tion and processing Systems facilities 80-10 Partial Loss of Non-Nuclear 3/7/80 All power reactor Instrument System Power facilities holding Supply During Operation OLs and cps 80-09 Possible Occupational 3/7/80 All holders of Health Hazard Associated power reactor OLs with Closed Cooling Systems and near term cps 80-08 The States Company Sliding 3/7/80 All power reactor Link Electrical Terminal facilities with an OL Block or a CP 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 I
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 8X8R Water Rod Lower 1/25/,80 All BWR Facilities End Plug Wear holder power reactor I
OLs or cps l
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