ML19274D064
| ML19274D064 | |
| Person / Time | |
|---|---|
| Site: | Perry, Fermi, Byron, Braidwood, Callaway, Clinton, Midland, LaSalle, 05000000, Zimmer, 05000484, Bailly, Marble Hill |
| Issue date: | 01/02/1979 |
| From: | Pappas H NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Wright G ILLINOIS, STATE OF |
| References | |
| NUDOCS 7901090309 | |
| Download: ML19274D064 (2) | |
Text
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State of Illinois Department of Public Health ATTN:
Mr. Gary N. Wright, Chief Division of Nuclear Safety 535 West Jefferson Screet Springfield, IL 62761 Gentlemen:
The enclosed IE Circular No. 78-19 titled " Manual Override (Bypass) of Safety System Actuation Signals" was sent to the following licensees on December 29. 1978, for infornation:
Cincinnati Gas 6 Electric Company Zimmer (50-358)
Cleveland Electric Illuminating Company Perry 1, 2 (50-440, 50-441)
Commonwealth Edison Company Braidwood 1, 2 (50-456, 50-457)
Byron 1, 2 (50-454, 50-455)
La Salle 1, 2 (50-373, 50-374)
Consumers Power Company Midland 1, 2 (50-329, 50-330)
Detroit Edison Company Fermi 2 (50-341)
Illinois Power Company Clinton 1, 2 (50-461, 50-462)
Northern Indiana Public Service Company Bailly (50-367)
Northern States Power Company Tyrone Energy Park 1 (50-484) 7901090309
3 State of Illinois JAN 02 379 Public Service of Indiana Marble Hill 1, 2 (50-546, 50-547)
Union Electric Company callaway 1, 2 (50-483, 50-486)
Sincerely, n
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$elen Pappas, Chief
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Enclosures:
1.
IE Circular No. 78-19 2.
List of IE Circulars Issued in 1978 cc w/encls:
Mr. D. W. Kane, Sargent & Lundy Central Files Reproduction Unit NRC 20b PDR Local PDR NSIC TIC
U.S. NUCLEAR REGULATORY COMMISSIOS OFFICE OF INSPECTION AND ENFORCEMENT REGION III December 29, 1978 IE Circular No. 7 6 - l ':
MANUAL OVERRIDE (BYPASS) 0F SAFETY SYSTEM ACTUATION SIGNALS Description of Circumstances:
A review of several recent events has raised questions about safet, system circuit designs which incorporate car.ual override (bypass) features.
The two events described below directly relate to the practice of containment purging during normal plate, operation by manually overriding certainment isolation signals.
In these instances the automatic isolatic, function of the purge system containment isola-tien valves was unintentionally made inoperable, and this conditicr was neitner continuously indicated in the control roce nor known to the plant operators.
During a review of operating procedures on July 25, 1978, the Northeast Nuclear Energy Company discovered that since May 1, 1978, intermittent containment purge operations had been conducted at Millstone Unit No. 2 with the safety actuation isolation signals to both inlet and outlet redundant containment isolation valves (48 inch butterfly valves) in the purge inlet and outlet penetrations manually overridden and inoperable.
The isolation signals which are required to automatically close the purge valves for containment integrity were manually overridden to allow purging of containment 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 thesc valves. To manually 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 a'iowed manual operation independent of any safety actuation signal. This circuitry was designed to permit reopening these valves after an accident to allow manual operation of certain safety equipment.
On September 6, 1978, the Public Service Electric and Gas Company advised the staff that, as a matter of routine, Salem Unit No. I has been venting the containment through the containment ventilation system valves to reduce pressure. In certain instances this venting has occurred with the containment high particulate radiation monitor isolation signal to the purge and pressure-vacuum relief valves overridden. Override of
IE Circular No. 78-19 December 29, 197E
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the containment isolation signal was accomplished by resetting the train A and B reset buttons. Under these circuentances, six valves in the containment vent and purge systems could be opened with a high particulate isolation signal present.
This override was performed after verifying that the actual containment 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 containment isolation signal to the purge valves and that the purge valves would not have automatically closed in the event of an emergency core cooling system (ECCS) safety injection signal.
These events and information gained from recent licensing actions have raised a generic concern relative to potential design deficiencies that could permit manually defeating a protection function.
Since all plants with construction permits must meet the requirements of IEEE 279, we recommend 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 physical features are provided to facilitate adequate administrative controls, and that the use of each such manual override is annunciated at the system level for every system impacted.
Compliance with Federal Regulation 50.55a(h) requirements will be verified by NRC through the licensing review process and during regular onsite inspections for plants with construction permits.
NRC's requirements relative to this matter have been conveyed to all operating plant licensee's via a generic letter.
Ne written response to this Circular is required.
If ymt require additional information regarding this matter, contact the Director of the appropriate NRC Regional Office.
IE Circular No. 78-19 December 29, 1978 LISTING OF IE CIRCULARS ISSUED IN 1978 Circular Subj ec t Date Issued To No.
of Issue 78-01 Loss of Well Logging 4/5/78 All Holders of Soercc Well Legeing Source Licenses 78-02 Proper Lubricating Oil 4/20/78 All Holders of for Terry Turbines Reactor OLs er cps 75-03 Packaging Greater Thar 5/12/78 All Holders cf Type A Quantities of Reactcr OLs, CFs, Low Specific Activity Fuel Cycle, Radioactive Material Priority I Materia:
for Transport and Waste risposal Licenses 75-04 Installation Error That 5/15/78 All Holders of Could Prevent Closing of Reactor OLs er Fire Doors cps 75-05 Inadvertent Safety Injection 5/23/7E All Holders cf During Cooldowr Reactor OLs er cps 76-Of Potential Commen Mode 5/23/78 All Holders of Flooding of ECCS Equiptent Reactor OLs or Rooms at BWR Facilities cps 78-07 Damaged Components of a 5/31/78 All Holders of Bergen-Paterson Series Reactor OLs or 25000 Hydraulic Test cps Stand 78-08 Environmental Qualification 5/31/78 All Holders of of Safety Related Equipment Reactor Ols or at Nuclear Power Plants cps 78-09 Arcing of General Electric 6/5/78 All Holders of Company Size 2 Contactors cps Enclosure Page 1 of 2
IE Circular No. 7E-;;
December 29, 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 ir Radiation Therapy Categories G and G1 78-11 Recirculation M-G 6/15/78 All Holders cf Set Overspeed Stops BWR OLs or cps 75-12 EPCI Turbine Centro 1 6/30/76 All Holders ei Valve lift Rod Bending EWR OLs or C;s fer plants wit" HPCI Terry Turt;nc 76-13 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, GA, LA, MS, SC 75-14 HIC 1 Turbine Reversing 7/12/76 All nolders of EWF Chamber Hold Dow Ec ting OLs or cps fcr plants with a HFCI Terry Turbine excepting Duane Arnold and Menticello 76-15 Checkvalves Fail to 7/20/76 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.
78-1E UL Fire Test 11/6/78 All Holders of Reactor OLs or cps Enclosure Page 2 of 2