ML19274D071
| ML19274D071 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 12/29/1978 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Zechella A EECOPS |
| References | |
| NUDOCS 7901090328 | |
| Download: ML19274D071 (1) | |
Text
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pamacu UNITED STATES O
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'o, NUCLE AR REGULATORY COMMISSION O
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I E 101 M ARIETTA STRE ET N.W.
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DEC 2 91978 In Reply Refer To:
RII:JPO 50-437 Offshore Power Systems Attn:
Mr. A. P. Zechella, President 8000 Arlington Expressway P. O. Box 8000 Jacksonville, Florida 32211 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, O
m ces P. O'Reilly D ector
Enclosures:
1.
15 Circular No. 78-19 2.
L.' = t of IE Circulars Issued in 1976 190 t o3 o 32.3
UNITED STATES NUCLFAR REGULATORY CO E SSION OFFICE OF INSPECTION AND ENFORCEMEITI' WASHINGTON, D.C.
20555 Dece=ber 29, 1978 IE Circular No. 78-19 MANUAL OVERRIDE (BYPASS) 0F SAFETY SYSTEM ACTUATION SIGNALS Description of Circu= stances:
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
=anually overriding contain=ent isolation signals.
In these instances the auto =atic isolaticn function of the purge syste= containment isola-tion valves was unintentionally =ade 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 containment 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 (L8 inch butterfly valves) in the purge inlet and outlet penetrations =anually 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 valves. To =anually override a safety actuation signal, the operator cycles the valve control switch to the closed position and then to the open position. This action energized a relay which blocked the safety signal and allowed =anual operation independent of any safety actuation This circuitry was desi ned to permit reopening these valves signal.
6 after an accident to allov =anual operation of certain safety equipment.
On Septe=ber 8,1978, the Public Service Electric and Gas Co=pany advised the staf f that, as a matter of routine, Sale: 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 containment high particulate radiation monitor isolation signal relief valves overridden. Override of to the purge and pressure-vacau:
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Dece=ber 29, 1978 IE Circular No. 78-19 the containment isolation signal was acco=plished by resetting the train A and B reset bottons. 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 for venting. The licensee, after further investigation of this practice, determined that the reset of the particulate alarm also bypasses the contain=ent isolation signal to the purge valves and that the puree valves would not have auto =atically closed in the event of an emergency core cooling syste (ECCC) safety injection signal.
These events and information gained fro: recent licensing actions have raised a generic concern relative to potential design deficiencies that could percit manually defeating a protection function.
Since all p] ants with construction permits cust meet the require =ents of IEEE 279, we reco==end that you review the design of all safety actuation signal circuits which incorporate a manual 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 phy:ical features are provided to facilitate adequate ad=inistrative controls, and that the use of each such manual override is annunciated at the syste= level for every syste= impacted.
Co:pliance with Federal Regulation 50.55a(h) require =ents vill be verified by NRC through the licensing review process and during NEC's regular onsite inspections for plants with construction permits.
require =ents relative to this matter 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 matter, contact the Director of the appropriate NRC Regional Office.
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IE Circular Nr 78-19 December 28, 1978 LISTIN3 0F IE CIRCULARS ISSUED IN 1978 Circular Subject 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 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 Weste Disposal Licenses 78-OL Installation Error That 5/15/78 All Holders of Could Prevent Closing of Reactor CLs or Fire Doors cps 78-05 Inadvertent Safety injection 5/23/78 All Holders of During Cooldown Reactor OLs or cps 78-06 Potentiel Co==on Mode 5/23/78 All H 1ders of Flooding of ECCS Equipment Reactor OLs or Roo=s at BWR Facilities cps 76-07 Damaged Co=ponents of a 5/31/78 All Holders of Bergen-Paterson Series Reactor OLs er 25000 Hydraulic Test cps Stand 74-08 Environmental Qualification 5/31/7E All Helders of of Safety Related Equip =ent Reactor OLs or at Nuclear Power Plants cps 76-09 Arcing of General Electrie 6/5/78 All Helders of Company Size 2 Contactors cps Enclosure Page 1 of 2
IE Circular No 78-19 December 28, 1978 LISTING OF IE CIRCUIARS 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 C1 78-11 Recirculation M-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 01s or cps for plants with HPCI Terry Turbine 78-13 Inoperability of Multiple 7/10/78 All Holders of Service Water Pumps 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 Arnold and Mont* cello 78-15 Checkvalves Tail to 7/20/78 All Holders of Close In Vertical Reactor OLs or cps Position 7.8-16 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 Falsifled and applicants Training Records for Reacter OLs.
78-18 UL Fire Test 11/6/78 All Holders of Reactor OLs or cps Enclosure Page 2 of 2