ML20037B243
| ML20037B243 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Byron, Braidwood, Quad Cities, Zion, LaSalle  |
| Issue date: | 09/23/1977 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Brian Lee COMMONWEALTH EDISON CO. |
| References | |
| NUDOCS 8009100692 | |
| Download: ML20037B243 (1) | |
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- Dochet Eon. 50-10,,50-237, 50-249, 50-255, 50-265, 50-295, 50-304, p "23 Jg77 50-373, 50-374, 50-454, 50-455, s
50-455, 50-457 Conno:niecith Edicen Company j
ATIN: lir. Dyron Lc r, Jr.
Vice President l
P.O. Box 767 i
Chicago, IL 60690 Gentic: son:
The enclosed Circu3cr No. 77--13, is forwarded to you for j
inf on.ation. If there are any questionc related to your understanding of tha suggeated actions, plcr.cc contact this l
office.
Sincerely,
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t arres G. Koppler Dirceter "aclosure:
IE Circular i
Ho. 77-13 j
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lir. B. S. Stephenson, j
Station Superintendent Mr. H. J. Kalivianakis, l
Plant Superintendent lir. J. S. Bitel, Plant Superintendent I
Mr. L. J. Eurke, Site
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Project Superintendent Mr. Gunnar Sorent.ca, Site Project Su;crintendent Mr. R. Couaro, Project Superintendant Centrcl Filec Reproduction Unit URC 20b l,,
PDR Local PDR NSIC TIC Anthony l'oicma, Esq., Attert:rc?
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September 23, 1977
.IE Circular.No. 77-13 REACTOR SAITfY SIGNALS REGATED DURING TESTING' On July-12, 1977, the Commonwealth Edison Company reported that while conducting a surveillance test at Zion Unit 2, test cinnals were simul-taneously injected.into several sensors which affected both protection and control systems.
Injection of these test signals resulte'd in:
(1) the loc of instrument indications for the affected. protection and-control systems, (2) thc' loss of au*:omatic control capability for the affected control systers, and.(3) the losc of automatic protection capability for the affectc1 protection cystems.
At the time of the event, the unit was in a hot shutdoun condition an'd.
preparations for start-up were underway.
Station management decided to perform a surveillence test of the reactor protection logic circuitry.
A ceabinction of test procedure inadequacies and the failure to follow prescribcid ad=inistrative controls related to instrumentation. testing led to the insertion of test signals which replaced the actual signals from three precouriner water level sensors, three water level. sensors in each of the four steen generatorc, four pressuriner pressure sensors and three flow sensors in cach of the primary coolant loops.
The test signals had been inserted for approximately 40 minutes uhen, due to unexpected f ndications of the main coolant pump seal flow rate and other anomalous indicatienc, the operator requcsted that the tcst signals be removed. When the test signals were removed, it was observed that the prescurized water level had dropped below the range of indication.
l The drop in pressuricer wcter Icyc1 resulted from the prescurizer water level test cignal being slightly higher than the automatic pressurizer level control net point.
In response to this condition the changing pump flow uas automatically reduced to the minimum pump flow rate, which was maint:ained until the tect niguals ucre removed. During this forty minute period the letdown flow remained constant.
Consequently, the rate at which coolant uac being removed from the pramary coolant cystem was approximately 75 gpm greater than the rate at uhich coolent van i
being returned to the system.
Approximately 5300 gallons of water was required to bring the pressurizer water level back to its original icvel of twenty-two percent.
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IE Circular No. 77-13 September 23, 1977 As_ mentioned above, operator action, in response to other available instrumention indications terminated the event.
Subsequent investiga-tion by the licensee revealed that no damage to plant equipment uas sustained during or after the event.
This incident represents un example of an event which resulted from a series of errors involving lan management control and impropc: attention i
of plant personnel to established procedures.
All holdcrc of operating licences should be aware of the potential for adverse operationcl ~ events which can' occur during perforcCice of parti-cular surveillance tests.
For example, if an excescive number of safety sensors are disabled simultaneously as uas the case in this event, automatic-action may not occur as intended.
Care must be taken to aceute that test signals do not negate automatic initiction of protection systems.
It is recommended that the follouing considerationc be incor-porated in your revicus of this matter.
1.
Facility procedures should specifically identify the limitations and restrictions which are required for ecch mode of operation during which testing or curvcillance activities may be conducted such that required safety protection systems uill remain operabic in accordance uith'the facility Technical Specifications.
2.
In order to p: ovide additional assurance that required safety related capabilitics of plant systems are not defeated during testing or surveillance activition, training programs for opera-tions and craft personnel should include ~ sufficient information to assure an indepth undarstanding of system functions, system interactions, and Technical Specification requirer..cnts.
3.
!!anagement controls should be strengthened ac necessary.to assure adherence to adcinistrative procedure: involving revieus, approvals, and cc:r.munication betucen, plant supervi-sion, operatorn and craf t personnel perfor:cing tenting and curveillanta activitics.
Such controls should consider the
" man-machine' interfacen,,and should assu're that the human component of thin pair is not overburda:n L a
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IE Circular No.-77-13~
-- - SeptemberJ23, 1977-No written response.to this Circular-is required.'
If.you require additional infurmation regarding this matter contact the. Director-of the appropriate URC Regional Office. -1E-inspectors will review this matter with licenuces during future inspections.
Enclosure:
List of IE Circulars:
Issued in 1977 e
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LISTIIG OF IE CIRCULARS ISSUED I: 1977
-CIRCULAR SUDJECT FIRST DATE OF ISSUED TO NO.
ISSUE 77-01 Halfunctions of 1-4-77 All holderc of Limitorque Valve Operating Lice-sq Operators (OL) or Ccnstre:d tion permit (CP' ~
77-02 Potential Heavy 2-15-77 All affected
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Spring Flooding holders of CLs77-02A Potential Heavy 2-16-77 All affected Spring Flooding holders of C?s 77-03 Fire Inside 2-28-77 All holders of a Motor Control OLs and cps Center 77-04 Inadequate Loch 3-17-77 Safegucrd Gr p Assemblica I, 11, IV, V, Licensces 77-05 Liquid Entrapment 3-24-77 All holders of in Valve Bonnets OLs and cps 77-06 Effects of Hydraulic 4-1-77 All holder: of Fluid on Electrical OL's and CPc Cable 77-07 Short Period During 4-12-77 Holders of Reactor Stcrtop BWR OLs 77-08 Failure of Feedwater 4-13-77 All holderc Sar.plc Probe of OLs 77-09 Improper Fuse 5-25-77~
All holders of Coordination In BUR EWR OLs or cps Standby Liquid Control System Control Circuits 77-10 Vacuum Conditionc 7-15-77
.All ho]dern cf Resulting in D.nnage to 0La Liquid Procens Tanks Enclo.sure Pa;;c 1 of 2
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f LISTIl!C OF IE CIRCULARS ISSUED Ill 1977 (Continued)
CIRCULAR.
SUBJF.CT FIRST DATE OF ISSUED TO NO.-
ISSUE 77-11' Leakage of Con-9-6-77 All holders of C'_s tainment Isolation and cps
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Valves with Resilient Seats 77-12 Dropped Fuel Assem-9-15-77 All holders of F.G blics at BWR Facili-OLs or.CPc-.
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