ML19274D074
| ML19274D074 | |
| Person / Time | |
|---|---|
| Site: | Farley  |
| Issue date: | 12/29/1978 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Mary Johnson ALABAMA POWER CO. |
| References | |
| NUDOCS 7901090331 | |
| Download: ML19274D074 (1) | |
Text
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DEC 2 91978 In Reply Refer To:
RII:JPO 50-364 Alabama Power Company Attn:
Mr. F. L. Clayton, Jr.
Executive Vice President Post Office Box 2641 Birmingham, Alabama 35291 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, N
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g_
ames P. O'Reilly D ector
Enclosures:
(
IE Circular No. 78-19 List of IT Circulars Issued in 1978 790109033/
DEC 2 e nyg Alabama Power Company cc w/ encl:
Mr. Oliver D. Kingsley, Jr.
Plant Manager Drawer 470 Ashford, Alabama 36312 Mr. R. E. Hollands, Jr.
QA Supervisor P. O. Box U Ashford, Alabama 36312 Mr. A. R. Earton Executive Vice President Post Office Box 2641 Birmingha=, Alaba=a 35291 Mr. H. O. Thrash, Manager Nuclear Generation Post Office Box 2641 Birmingha=, Alabama 35191 Mr. C. Biddinger, Jr., Manager Corporate Quality Assurance Post Office Box 2641 Birminght=, Alaba=a 35291
UNITED STATES NUCLFAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT 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 belov 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 system 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, intermittent contain=ent purge operations had been conducted at Millstone Unit No. 2 vith the safety actuation isolation signals to both inlet and outlet redundant contain=ent isolation valves (kB inch butterfly valves) in the purge inlet and outlet penetrations manually overridden and inoperable.
The isolation signals which are required to auta=atically close the purge valves for containment integrity were manually overridden to allow purging of contain=ent with a high radiation signal present. The manual override circuitry designed by the plant's architect / engineer defeated not only the high radiation signal but also all other isolation signals to these To manually overr.ide a safety actuation signal, the operator valves.
cycles the valve control switch to the closed position and then to the This action anergized a relay which blocked the safety open position.
signal and allowed =anual operation independent of any safety actuation This circuitry was designed to permit reopening there valves signal.
after an accident to allow manual operation of certain safety equipment.
On September 8, 2978, the Pu'olic Service Electric and Gas Cocpany advised the staff that, as a matter of routine, Salem Unit No. I has been venting the contain=ent through the containment ventilation syste=
In certain instances this venting has occurred valves to reduce pressure.
with the contain=ent high particulate radiation monitor isolation signal relief valves overridden. Override of to the purge and pressure-vacuu:
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Dece=ber 29, 1978 IE Circular No. 78-19 the contain=ent isolation signal was acco=plished by resetting the train A and B reset buttons. Under these circumstances, six valves in the contain=ent vent and purge syste=s could be opened with a high particulate isolation signal present. This override was perfor=ed after verifying that the actual contain=ent particulate levels were acceptable The licensee, after further investigation of this practice, for venting.
deter =ined that the reset of the particulate alar = also bypasses the containment isolation signal to the purge valves and.that the purge valves vould not have auto =stically closed in the event of an e=ergency core cooling syste= (ECCS) safety injection signal.
These events and information gained fro = recent licensing actions have raised a generic concern relative to potential design deficiencies that could per=it manually defeating a prctection function.
Since all plants with construction per=1ts =ust meet the require =ents of IEEE 279, we reco==end that you review the design of c11 safety setuation 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 other safety actuation signal, that sufficient physical features are provided to facilitate adequate administrative controls, and that the use of each such =anual override is annunciated at the syste= level for every syste= impacted.
Co=pliance with Federal Regulation 50.55a(h) requirements will be verified by NEC through the licensing review process and during NRO's regular onsite inspections for plants with construction permits.
require =ents relati te to this =atter have been conveyed to all operating plant licensee's via a generic letter.
No written response to this Circular is required.
If you require additional information regarding this =atter, contact the Director of the appropriate NRC Regional Office.
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IE Circular No. 78-19 Dece=ber 28, 1978 LISTING OF IE CIRCULARS ISSUED IN 1978 Circular Subject Date Issued To No.
of Issue 78-01 Loss of Well Logging h/5/78 All Eolders 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 Packaging Greater Than 5/12/78 All Holders of Type A Quantities of Reactor OLs, cps, Lov Specific Activity Fuel Cycle, Radioactive Material Priority I Material for Transport and Waste Disposal Licenses 76-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 73-06 Potential Co==en Mode 5/23/78 All Holders of Flooding of ECCS Equip =ent Reactor OLs or Rooms at BWR Facilities cps 76-07 Damaged Co=ponents of a 5/31/78 All Holders of Bergen-Paterson Series Reactor OLs or 25000 Hydraulie Test cps Stand 76-0 B Environmental Qualification 5/31/78 All Holders of of Safety Related Equip =ent Reactor OLs or at Nuclear Power Plants cps 78-09 Arcing of General Electrie 6/5/78 All Holders of Co=pany Size 2 Contactors cps Enclosure Page 1 of 2
IE Circular No. 78-19 December 28, 1978 LISTING OF IE CIRCULARS ISSUED 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 G1 78-11 Recirculation M-G 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 h ltiple 7/10/78 All Holders of Service Water Pucps Reactor OLs and cps except for plants located in: AL, AK, CA, FL, CA, IA, MS, 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 Arr.old and Monticello 76-15 Checkvalves Fail to 7/20/78 All Helders 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 Trair..'.ng Record s far Reactor OLs.
78-18 UL Fire Test 11/6/78 All Holders of Reactor OLs or cps Enclosure Page 2 of 2