ML18139A152
| ML18139A152 | |
| Person / Time | |
|---|---|
| Site: | Surry, North Anna  |
| Issue date: | 03/31/1980 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Ferguson J VIRGINIA POWER (VIRGINIA ELECTRIC & POWER CO.) |
| References | |
| NUDOCS 8004150540 | |
| Download: ML18139A152 (4) | |
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"°o In Reply Refer To:
RII:JPO 50-338, 50-339 50-40a 50-405 4P-2ao;>so-2§.D UNITED STATES NUCLEAR REGULATORY COMMISSION REGION II 101 MARIETTA ST., N.W., SUITE 3100 ATLANTA, GEORGIA 30303 MAR 3 1 1980 Virginia Electric and Power Company Attn:
J. H. Ferguson Executive Vice President-Power P. O. Box 26666 Richmond, VA 23261 Gentlemen:
e This Information Notice is provided as 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.
Enclosures:
- 1.
IE Information Notice No. 80-12
- 2.
List of IE Information Notices Recently Issued Sincerely, James P. O'Reilly Director
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Virginia Electric and Power Company cc w/encl:
e W.R. Cartwright, Station Manager Post Office Box 402 Mineral, Virginia' 23117 P. G. Perry Senior Resident Engineer Post Office Box 38 Mineral, Virginia 23117 W. L. Stewart, Manager Post Office Box 315 Surry, Virginia 23883 MAR 3 1 1980
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e UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D.C.
20555 March 31, 1980 e
SSINS No. :
6870 Accession No. :
8002280654 IE Information Notice No.: 80-12 INSTRUMENT FAILURE CAUSES OPENING OF PORV AND BLOCK VALVE 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 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 value of 2000 psig to 1950 psig before the PORV and block valves could be closed.
The. operator immediately overrode the open signal to the valves and closed the valves to stop depressurization.
The pressurizer pressure then immediately returned to normal.
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 pressure controller and in other similar plant bistables had been experienced previously.
0Also, 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-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 of bistable with a solid state design which does not depend on a light source and which is expected to be more reliable.
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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e IE Information Notice No. 80-12 March 31, 1980 RECENTLY ISSUED Information Notice No. 80-12 80-11 80-10 80-09 80-08 80-07 80-06 80-05 80-04 80-03 80-02 IE INFORMATION NOTICES Subject Instrument Failure Causes Opening of PORV and Block Valve General Problems with ASCO Valves in Nuclear Application Including Fire Protection Systems Partial Loss of Non-Nuclear Instrument System Power Supply During Operation
- Possible Occupational Health Hazard Associated with Closed Cooling Systems The States Company Sliding Link Electrical Terminal Block Pump Shaft Fatigue Cracking Notification of Significant Events Chloride Contamination of Safety Related Piping BWR Fuel Exposure in
- Excess of Limits Main Turbine Electro-Hydraulic Control System 8X8R Water Rod Lower End Plug Wear Date Issued 3/31/80 3/14/80 3/7/80 3/7/80 3/7/80 2/29/80 2/27/80 2/8/80 2/4/80 1/31/80 1/25/80 e
Enclosure.
Issued To All power reactor Facilities Holding OLs and CPs All holders of Reactor OL, CP, fuel fabrica-tion and proces.sing facilities All power reactor facilities holding OLs and CPs All holders of power reactor OLs and near term CPs All power reactor facilities with an 01 or a CP All Light Water Reactor Facilities holder power reactor OLs and CPs All holders of Reactor OLs and to near term 01 applicants All licensees of nuclear power reactor facilities a*nd applicants and holders o.f nuclear power reactor CPs All BWR's holding a power reactor OL or CP All holders of power reactor OLs and CPs All BWR Facilities holder power reactor OLs or CPs