ML19274D069
| ML19274D069 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 12/29/1978 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | John Miller GEORGIA POWER CO. |
| References | |
| NUDOCS 7901090326 | |
| Download: ML19274D069 (1) | |
Text
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UNITED ST ATES na Rico j
'o NUCLEAR REGULATORY COMMISSION
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101 M ARIETT A STRE ET. N.W.
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ATL ANT A. GEORGI A 30303 g
DEC 2 91978 In Reply Refer To:
RII:JPO 50-424, 50-425 Georgia Power Company Attn:
Mr. J. H. Miller, Jr.
Executive Vice President 270 Peachtree Street, N. W.
Atlanta, Georgia 30303 Gentlemen:
The enclosed Circular 78-19 is forwarded to you for information.
If there are any questions related to your understanding of the requested actions, please contact this office.
Sincerely, g(6
=es P. O'Reilly D ector
Enclosures:
1.
IE Circular No. 78-19 2.
List of IE Circulars Issued in 1978 19010905R4 (N
DEC 2 91978
, Georgia Power Company cc w/ encl:
K. M. Gillespie Construction Project Manager Plant E. 1. Hatch P. O. Box 439 Baxley, Georgia 31513 M. Manry, Plant Manager Plant E. 1. Hatch P. O. Box 442 Baxley, Georgia 31513 W. M. Johnston Project Construction Manager Vogtle Nuclear Plant P. O. Box 282
. Waynesboro, Georgia 30830
1 UNITED STATES NUCLEAR REGULATORY C0!EISSION OFFICE OF INSPECTION AND ENFORCEMIC WASHINGTON, D.C.
20555 Dece=ber 29, 1978 IE Circular No. 78-19 MANUAL OVERRIDE (BYPASS) 0F SAFETY SYSTEM ACTUATION SIGNALS Description of Circumstances:
A review of several recent events has raised questions about safety syste: circuit designs which incorporate manual override (bypass) features. The two events described below directly relate to the practice of contain=ent purging during normal plant operation by manually overriding contain=ent isolation signals.
In these instances the auto =atic isolation function of the purge syste= contain=ent isola-tion valves was unintentionally made inoperable, and this condition was neither continuously indicated in the control roo: nor known to the plant operators.
During a review of operating procedures on July 25, 1978, the Northeast Nuclear Energy Co=pany discovered that since May 1,1978, inter =ittent contain=ent purge operations had been conducted at Millstone Unit No. 2 with the safety actuatiou isolation signals to both inlet and outlet redundant contain=r ' 4. solation valves (L8 inch butterfly valves) in the purge inlet and outlet penetrations =anually overridden and inoperable.
The isolation signals which are required to autncatically close the purge valves for contain=ent integrity were manually overridden to allow purging of containment with a high radiation signal present. The =anual override circuitry designed by the plant's architect / engineer defeated not only the high radiation signal but also all other isolation signals to these valves. To manually override a safety actuation signal, the operator cycles the valve control svitch to the closed position and then to the open position.
This action energized a relay which blocked the safety signal and allowed manuel operation independent of any safety actuation signal. This circuitry was designed to permit reopenhg these valves after an accident to allow manual operation of certain safety equip =ent.
On Septe=ber 8, 1978, the Public Service Electric and Gas Co=pa.gv advised the staff that, as a matter of routine, Sale: Unit No. I has been venting the contain=ent through the contain=ent ventilatien syste:
valves to reduce pressure.
In certain instances this venting has occurred with the containment high particulate radiation monitor isolation signal
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to the purge and pressure-vacuu: relief valves overridden. Override of I of 2 A
1 IE Circular No. 78-19 Dece=ber 29, 1978 the contain=ent isolation signal was acco=plished by resetting the train A and B reset buttons. Under these circu= stances, six valves in the contain=ent vent and purge syste=s coul' be opened with a high particulate isolation signal present. This override was perfor=ed after verifying that the actual contain=ent particulate levels vere acceptable for venting. The licensee, after further investigation of this practice, deter =ined that the reset of the particulate alar: also bypasses the contain=ent isoletion signal to the purge valves and that the purge valves vould not have auto =atically closed in the event of an e=ergency core cooling syste= (ECCS) safety injection signal.
These events and infor=ation gained fro = recent licensing actions have raised a generic concern relative to potential design deficiencies that could per=it =anually defeating a protection function.
Since all plants with construction permits =ust =eet the require =ents of IEEE 279, we reco==end that you review the design of all safety actuation signal circuits which incorporate a =anual override feature to ensure that overriding of one safety actuation signal does not also cause the bypass of any otner safety actuation signal, that sufficient physical features are provided to facilitate adequate ad=inistrative controls, and that the use of each such =anual override is annunciated at the syste= level for every syste= i=pacted.
Cc=pliance with Federal Begulation 50.55a(h) requirements vill be verified by NRC through the licensing review process and during NRC's regular onsite inspections for plants with construction per=its.
require =ents relative to this =atter have been conveyed to all operating plant licenset's via a generic letter.
No written response to this Circular is required.
If you require additional infor=ation regarding this =atter, contact the Director of the appropriate NRC Regional Office.
2 of 2
1 IE Circular No. 78-19 Dece=ber 28, 1978 LISTIN3 0F IE CIRCULARS ISSUED IN 1978 Circular Scsject Date Issued To No.
of Issue 78-01 Loss of Well Logging L/5/78 All Holders of Source Well Logging Source Licenses 78-02 Proper Lubricating 011 h/20/78 All Holders of for Terry Turbines Reactor OLs or cps 78-03 Packasing Greater Than 5/12/78 All Helders of Type A Quantities of Reacter OLs, cps, Lov Specific Activity Fuel Cycle, Radioactive Material Priority I Material for Transport and Waste Disposal Licenses 78-OL Installation Error That 5/15/78 All Holders of Could Prevent Closing of Reactor OLs or Fire Doors cps 78-05 Inadvertent Safety Injection 5/23/78 All Holders of During Cooldown Reactor OLs or cps 78-06 Potential Co==on Mode 5/23/78 All Holders of Flooding of ECCS Equipment Reactor OLs or Roo=s at BWR Facilities cps 78-07 Da= aged Co=ponents of a 5/31/78 All Ec1ders of Bergen-Paterson Series Reactor OLs or 25000 Hydraulic Test cps Stand 78-08 Environ = ental Qaalification 5/31/78 All Holders of of Safety Related Equipment Reactor OLs or at Nuclear Power Plants CFs 78-09 Areing of General Electrie 6/5/78 All Helders of Company Size 2 Contactors cps Ehelosure Page 1 of 2 r
IE Circular No. 78-19 December 28. 1978 LISTING OF IE CIRCULARS ISSLED IN 1978 Circular Subject Date of Issued to No.
Issue 78-10 Control of Sealed 6/14/78 All Medical Sources Used in Licensees in Radiation Therapy Categories C and C1 78-11 Recirculation H-C 6/15/78 All Holders of Set Overspeed Stops BWR OLs or cps 78-12 HPCI Turbine Control 6/30/78 All Holders of Valve Lift Rod Bending BWR OLs or cps for plants with HPCI Terry Turbine 78-13 Inoperability of Multiple 7/10/78 All Holders of Service Water Pucps Reactor OLs and cps except for plants located in: AL. AK, G. R. M. M. E.
SC 78-14 HPCI Turbine Reversing 7/12/78 All Holders of BWR Chamber Hold Down Bolting OLs or cps for plants with a HPCI Terry Turbine excepting Duane Arnold and Monticello 76-15 Checkvalves Fail to 7/20/78 All Holders of Close In Vertical Reactor OLs or cps Position 78-16 Limitorque Valve 7/26/78 All Holders of Actuators Reactor OLs or cps 78-17 Inadequate Guard Training /
10/13/78 All Holders of Qualification and Falsified and applicants Training Records for Reactor OLs.
78-18 UL Fire Test 11/6/78 All Holders of Reactar OLs or cps Enclosure Page 2 of 2