ML20062D329
| ML20062D329 | |
| Person / Time | |
|---|---|
| Site: | Dresden, Oyster Creek, Surry, Ginna, Diablo Canyon, 05000000, Trojan |
| Issue date: | 07/29/1982 |
| From: | Michelson C NRC OFFICE FOR ANALYSIS & EVALUATION OF OPERATIONAL DATA (AEOD) |
| To: | Lafleur J NRC OFFICE OF INTERNATIONAL PROGRAMS (OIP) |
| References | |
| NUDOCS 8208060030 | |
| Download: ML20062D329 (21) | |
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t'EtiORAtlDUM FOR:
Joseph D. Lafleur, Jr., Deputy Director Office of International Programs FP,0M:
Carlyle Michelson, Director Office for Analysis and Evaluation of Operational Data
SUBJECT:
IRS REPORTS Please forward the following enclosed IRS reports to Mr. Otsuka of the NEA:
1.
Effects of Fire Protection System Actuation on Safety-Related Equipment.
2.
Seismic Qualification of Safety-Related Systems.
3.
Centrifugal Charging Pump (CCP) Miniflow Recirculation Valve Closure causes CCP to fluctuate.
Original Signed by Carlyle Micholson Carlyle Michelson, Director Office for Analysis and Evaluation of Operational Data
Enclosure:
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38, bd. Suchet 75016 Paris INCIDENT REPORTING SYSTEM Tel. 524.96.93 l
Telu 630668 AEN/NEA RESTRICTED N r.ms DIFFUSION RESTREINTE l
Title - Titre Effects of Fire Protection System Actuation on Safety-Related Equipment Country - Pays Date of Incident - Date de l 'inciden t Numer us United States Type of Reactor - Type de rdacteur Plant - Centrale Licensee - D6tenteur du permis dsexploitation fiumerous
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Unit N'
- Tranche n*
Power - Puissance First Commercial Operation -
MWe(net)
Date de mise en service Systems or Components Affected - Systhmes ou composants affectss Etat initial de la tranche Initial Plant Condition Way in which Incident was Detected ?
Comment l' incident a-t-il 6ts dstect6 ?
Radiation Exposure or Radioactivity Release -
Exposition aux rayonnements ou libdration de radioactiviti Date of Receipt - Date de rdception
]
Date of Distribution - Date de distribution i.xent description, possible causes, actions taken or planned and lessons learned (safety significance of incident) should be included in the following pages.
Description de l' incident, causes possibles, mesures prises au projetEes et
< ~, : ~.e - r o c tirne (cir.nification de R'ineident pour la s0 ret 6) doivent figurer
The following events are included in a single IRS report because they represent incidents where safety-related equipment subjected to water spray from the fire protection system was rendered inoperable.
The events also indicated that spurious
-.attuation of fire protection systems can be initiated by operator error, by steam, high humidity, or maintenance activities in the vicinity of fire protection systems detectors.
Potential interactions between fire protection systems and other systems that affect the operation of safety-related systems need to be thoroughly understood.
All safety-related and essential support equipment located in areas where fire protection spray systems are provided must perform its intended function both during and following the activation of the fire protection system.
Attached reports:
1.
Water in Diesel Generator Fuel Oil Storage Tanks 2.
Hydrogen Recombiner Discovered Inoperable 3.
Inadequate Ventilation for Engineered Safety Features Equipment 4.
Inadvertent Actuation of Fire Suppression System 5.
Spurious Actuation of Fire Suppression System 6.
Damage Caused by Fire Suppression System l
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INCIDENT REPORTING SYSTEM N
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DIFFUS10f1 RESTRElf4TE Title - Titre Water in Diesel Generator Fuel Oil Storage Tanks Pays Date of Incident - Date de l' incident Country
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May 28, 1981 United States Type de r4acteur l
Type of Reactor PWR Plant - Centrale 1icensee - Dstenteur du permis d* exploitation Surry Virginia Electric Power Company
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unit n* - Tranche n*
2 s
Westinghouse Power - Puissance First Commercial Operation - HOY l9I3 l
775 MWe(net)
Date de mise en service l
l Systems or Components Affected - Systbmes ou composants affect 6s l
l Emergency Diesel Generator Fuel Oil Tanks l
l Initial Plant condition - Etat initial de la tranche 100% power l
l Wa y in
- which Incident was Detected ?
Comment l' incident a-t-il st6 d6tect6 ?
Routine sampling I
I Radiation Exposure or Radioactivity Release -
Exposition aux rayonnements ou lib 6tation de radioactivit6 flone Date of Receipt - Date de r6ception D3te of Distribution - Date de distribution c
Event description, possible causes, actions taken or planned and lessons learned (safety significance of incident) should be-included in the following pages.
Description de l' incident, causes possibles, mesures prises ou projet6cs et
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Event Description lhere are three diesel generators that serve both Units 1 and 2 at Surry.
The generators are supplied with diesel fuel by the system shown in Figure 1.
There is one above ground tank (1-HS-TK-1) which supplies fuel for two underground seven-day storage tanks.
The underground tanks then supply the one-day storage tanks (each line of the underground tanks feeds all three one-day tanks).
The one-day tanks then supply the diesel generators.
On May 28, 1981, a routine sample of one of the underground-tanks revealed excess water.
It was determined that water from the fire suppression system was inadvertently added to the above ground tank.
The fire suppression system employs a foam suppressant which is mixed with water.
The water flows from a fire hydrant through a manual valve in two inch pipe through a foam induction nozzle to a sparger inside the fuel tank. The operation of the system requires the manual connection of the foam cannister to the nozzle and opening the manual valve and fire hydrant. The addition of water to the tank occurred when a hose was connected to the fire hydrant to test the reactor shield tank prior to its installation.
Evidently, the manual valve was open, which provided a flow path to the fuel storage tank after the hydrant was opened. After the water had been added to the storage tank the tank was isolated and fuel oil was drained until the sample showed negligible amounts of water.
However, the sample was not taken from the lowest elevation of the tank, which resulted in water accumulating in the under-ground and day tanks.
Cause of Event The cause of this event has been determined to be inadequate administrative controls for the fire suppression system.
Reason for Reporting Since the above ground tank supplies fuel to the underground tanks and ultimately the diesel generators, this is reportable pursuant to criterion 6, " Incidents of Potential Safety Significance."
Actions Taken Immediate action taken was to drain the water via the transfer suction strainer drains.
Subsequently all tanks were sampled and the water content was within
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allowable limits.
The licensee has also implemented a number of long-term measures to prevent recur-rence of a similar event and to ensure the quality of the diesel fuel stored in the above ground tank.
These include:
1.
Administrative controls to restrict use of fire hydrant to only fire protection.
2.
Monthly surveillance procedures to test the diesel fuel oil above ground, underground, and day tanks for water.
Additional surveillance testing'is required if the fire hydrant has been opened.
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- 3.
The manual valve in the water supply piping is locked closed and tagged.
4.
A drain line downstream of the foam induction nozzle is locked-open to indicate water leakage into the fire suppression system.
Daily surveillance requirement on the drainline has been added to the operator's log.
Corrective action has been specified when leakage is detected.
5.
The surveillance procedure for the monthly test identifies the sample location by valve number corresponding to the lowest elevation in the tank.
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DIFFUSION RESTREINTE Title - Titre Hydrogen Recombiner Discovered Inoperable Country - Pays Date of Incident - Date de l' incident July 28,1981 United States Type of Reactor - Type de re.acteur PWR Centrale Licensee - Ddtenteur du permis d' exploitation Plant Troj an Portland General Electric Company
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Unit N*
- Tranche n*
Westinghou se Power - Puissance First Commercial Operation -
pay lg,6 1130 nwe(net)
Date de mise en service Syst mes ou composants affectss Systems or Components Affected Hydrogen Reconbiner Initial Plant Condition - Etat initial de la tranche Steady State at 90% Power Way in which Incident was Detected ?
Comment l' incident a-t-il st4 d4tects ?
Operator tour Radiation Exposure or Radioactivity Release -
Exposition aux rayonnements ou libiration de radioactivitd None Date of Receipt - Date de rdception Date of Distribution - Date de distribution Event description, possible causes, actions taken or planned and lessons learned (ssfety significance of incident) should be included in the following pages.
Description de l' incident, causes possibles, mesures prises ou projet6es et enseignements tir6s (signification de l' incident pour la sGrets) doivent figurer sur les pages suivantes.
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Event Description On July 28, 1981, during steady state operations with the plant at 80% power, the control room operator noticed that control power had been lost to the "B" train hydrogen recombiner.
Cause of Event The loss of control power was due to inadvertent activation of the fire protection deluge system while welding in the electrical penetration This caused a short circuit and loss of control power to area.
hydrogen recombiner.
Reason for Reporting This cccurrence is a procedural maintenance deficiency and is reportable pursuant to criterion 3, "Significant Deficiencies in Design, Construction, Operation, or Safety Evaluation."
It is also a potential generic problem and so is reportable under criterion 4.
Actions Taken Corrective action was taken to replace the shorted control power transformer.
In addition, The hydrogen recombiner was then tested and declared operable.
maintenance personnel were counseled concerning proper ventilation for welding in enclosed areas and bu'rning permits are under revision to verify that ventilation requirements are met.
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Tel. 524.96.93 Tetex 630668 AEN/NEA RESTRICTED ND.lRS DIFFUSION RESTREINTE l
Title - Titre Inadequate Ventilation for Engineered Safety Features Equipment Country - Pays Date of Incident - Date de l 'inci den t September 10, 1981 United States Type f Reactor - Type de r6acteur PWR Plant - Centrale Licensee - Dstenteur du permis d' exploitation Portland General Electric Company Trojan Manufacturer - Fabricant Unit N*
- Tranche n
- Westinghouse Bower - Puissance
.First Co~mmercial Operation -
1130 nwe(net)
Date de mise en service yay 1975
' Systems or Components Affected - Systbmes ou composants affectis Preferred Instrument and Control Power Buses Initial Plant Condition - Etat initial de la t,r a n ch e l
100% power Way in which Incident was Detected ?
Comment l' incident a-t-il sts dstect6 7 i
Hiah Ambient Temoeratures Radiation Exposure or Radioactivity Release -
Exposition aux rayonnements ou libdration de radioactivits None Date of Receipt - Date de rdception Date of Distribution - Date de distribution Ev2nt description, possible causes, actions taken or planned and lessons learned
[
(' safety significance of incident) should be included in the following pages.
Description de l' incident, causes possibles, mesures prises ou projetses et enseignements tires (signification de l' incident pour la sGrets) doivent figurer sur les pages suivantes.
kj Y Event Description It was determined that inadequate ventilation for the "A" train preferred instrument and control power buses existed as a result of the installation of a three-hour fire barrier between the "A" and "B" instrument and control power trains.
In response to the tiRC Fire Protection SER dated March 9, 1978, and letter of March 18, 1980 requiring a three-hour rated fire barrier between trains of ESF electrical equipment, a fire wall was built to provide separation of the "A" and "B" train preferred instrument and control power buses.
The installation of this wall created a new room which enclosed those buses for the "A"
train.
During operation, high ambient temperatures in the room led to an engineering investigation which revealed that the ventilation equipment in the room was not capable of maintaining room temperatures in the recommended range for ESF-related equipment operation and was not seismically qualified.
Cause of Event The cause of the occurrence was an inadequate interdisciplinary review which resulted in an incomplete safety evaluation for the plant design change that created the fire barrier.
Calculation of cooling requirements for the installed heat loads versus cooling capability of the installed ventilation equipment were not performed.
In addition, the ventilation support syste.m's seismic qualification was not verified.
The supply of cooling water to the cooler was not safety grade, nor was the motor supplied with Class 1E power.
Reason for Reporting to IRS This event is being reported pursuant to criteria 3, "Significant Deficiencies in Design, Construction, Operation, or Safety Evaluation."
It is also a potential generic problem and is, therefore, reportable pursuant to criterion 4.
Actions Taken Initial action taken was to install portable blowers through the open doors of the fire barrier and institute an hourly fire inspection by plant security personnel.
After an engineering analysis to determine air flow and cooling requirements in the room, a 100-square foot area of the fire barrier was removed at the points of air flow entry and exit.
Upon completion of this modification to the barrier, temperatures in the room dropped from 1000F to approximately 750F. Action has been taken to increase the cooling capability of the room ventilation system and provide support systems that meet ESF design criteria.
Upon completion of these modifications, the three-hour fire barrier will be restored.
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38, bd. Suchet 75016 Paris INCIDENT REPORTING SYSTEM Tel. 524.96.93 Telex 630668 AEN/NEA RESTRICTED ND IRS DIFFUSION RESTREINTE Title - Titre i
Inadvertent Actuation of Fire Suppression System Country - Pays Date of Incident - Date de l' incident ti vember 14, 1981 United States Type of Reactor - Type de r6acteur PWR Plant - Centrale Licensee - D4tenteur du permis d' exploitation Ginna Rochester Gas and Electric Company nu c urer - Fa W cant Unit N*
Tranche n*
Westinghouse Power - Puissance First Commercial Operation - IbOYCh ISIO 490 MWe(net)
Date de mise en service Systems or Components Affected - Systemes ou composants affect 6s Control Rods Initial Plant Condition - Etat initial de la tranche 100% Power way in which Incident was Detected ?
Comment l' incident a-t-il 6ts dstects ?
Alarms Radiation Exposure or Radioactivity Release -
Exposition aux rayonnements ou libstation de radioactivit6 fione l
Date of Receipt - Date de rsception Date of Distribution - Date de distribution Evtnt description, possible causes, actions taken or plannc3 and lessons learned
.(ssfety significance of incident) should be included in the following pages.
Description de l' incident, causes possibles, mesures prises ou projet6es et enseignements tir6s (signification de l' incident pour la sGret6) doivent figurer sur les pages suivantes.
o Event Description During startup testing of the new fire suppression system, an inadvertent actuation caused various power cabinets and electrical equipment'in the turbine and intermediate buildings to be sprayed. A manual reactor. trip was initiated at 10:26 am following indication of two dropped rods and I
numerous control room annunciator 41&rms. The dropped rods were attributed to a trip of the "A" RPS MG set which may have reduced voltage enough to drop two rods.
All systems functioned properly following the trip and the plant was maintained in " hot shutdown" status while operability of equipment affected by the suppression system was assured.
Cause of Event Failure to follow test procedures caused actuation of several portions of the fire suppression system.
Reason for Reporting This event is being reported pursuant to criteria 2.4, " Degradation of Systems Required t,o Control Criticality."
It is also a potential gener.ic problem and is therefore reportable according to criterion 4.
Actions Taken All affected components were repaired.
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3 8, bd. Suchet 75016 Paris INCIDENT REPORTING SYSTEM Tel. 524.96.93 Telex 630668 AEN/NEA 1
i RESTRICTED i
ND, IRS DIFFUSI0tf RESTRElt4TE Title - Titre Spurious Actuation of Fire Suppression System
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Country - Pays Date of Incident - Date de l' incident ricvember 30, 1981 United States Type of Reactor - Type de r6acteur BWR Plant - Centrale Licensee - D6tenteur du permis d' exploitation Conmmwealth Edison Dresden
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Unit N*
- Tranche n*
3 General Electric Power - Puissance First Commercial Operation -
ctober 1971 794 MWe(net)
Date de mise en service Systems or Components Affected - Systbmes ou composants affect 6s High Pressure Coolant Injection System Initirl Plant Condition - Etat initial de la tranche 14% Sower, Startup in Progress Way in which Incident was Detected ?
Comment l' incident a-t-il 6td ddtecc6 ?
Fire System Initiation Alarm Sounded Raciation Exposure or Racioactivity Release -
Exposition aux rayonnements ou lib 6:ation de radioactivit6 flone Date of Receipt - Date de tsception Date of Distribution - Date de distribution Event description, possible causes, actions taken or planned and lessons learned (stfety significance of incident) should be included in the following rages.
Description de l' incident, causes possibles, mesures prises ou projetses et enseignements tirns (signification de l' incident pour la strets) doivent figurer ent ! r-w ee cuivantes.
O Event Description Unit startup was in progress when the control room received a HPCI room fire system initiation alarm from the south ionization smoke detector.
The HPCI system was declared inoperable and the HPCI steamline isolated.
An Unusual Event -
was declared and a normal unit shutdown initiated.
Cause of Event The cause of the fire system initiation is believed to have been a buildup of humidity / steam vapor in the HPCI room.
The smoke detector operates on ionization principle and is usually activated by the presence of combustion products.
Discussions with the manufacturer of the smoke detector indicated that the detector may actuate if exposed to a high concentration of water vapor.
The HPCI room has had a history of high humidity / steam because of steam leaks and the leakoff / drain system which runs to the sump in the HPCI room.
Temporary ventilation was not operating prior to the occurrence which would have reduced the water vapor concentration. The smoke detector continued to intermittently alarm until the ventilation was restored.
Reason for Reporting This event is being reported pursuant to criterion 2.5, " Degradation of Systems Required to Control the System Pressure or Tempe,atdre."
It is also a potential generic problem and so is reportable according tc criterion.4.
Actions Taken Ventilation to the HPCI room was restored and a review was made of the fire protection detectors and the ventilation system for p : ible modification to improve reliability.
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ND.lRS DIFFUSION RESTREINTE Titre TJtle Damage Caused by Fire Suppression System Date de l' incident Country - Pays Date of Incident January 9, 1982 United States Type of Reactor - Type de r6acteur BWR Plant - Centrale Licensee - D6tenteur du permis d ' exploitation GPU Nuclear, Inc.
Oyster Creek
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Tranche n*
1 Unit N*
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Puissance First Commercial Operation ggggmyg7 39gg Power MWe(net)
Date de mise en service
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Systems or Components Affected - Systhmes ou composants affectds Water Level and Pressure Indicators Initial Plant Condition - Etat initial de la tranche Cold Shutdown Way in which Incident was Detected ?
Comment l' incident a-t-il st6 d6tect6 ?
Activation of Fire Suppression System i
Radiation Exposure or Racioactivity Release -
Exposition aux rayonnements ou libdration de radioactivits None ll 1
Date of Receipt - Date de riception y
Date of Distribution - Date de distribution t
Event description, possible causes, actions taken or planned and lessons learned (safety significance of incident) should be included in the following pages.
causes possibles, : esures prises ou projetses et Description de l' incident,--
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Event Description With the plant in cold shutdown at about 9:50 am, the auxiliary pump on the reactor water cleanup system seized and its motor overheated.
Smoke from the motor, activated the fire suppression system on th,e north side of the reactor building at the 50-foot elevation. The fire suppression system was secured at 10:25 am, Water spray from the suppression system shorted out theposition indication on one torus vent valve, damaged one reactor lo-lo water level sensor and one reactor high pressure sensor.
Cause of Event The cause of the event was water spray from the fire suppression system.
Reason for Reporting This event is being reported pursuant to criterion 3, "Significant Deficiencies in Design, Construction, Operation, or Safety Evaluation."
It is also a potential generic problem and so is reportable according to criterion 4.
Actions Taken Damaged equipment was repaired and returned to service.
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D AGENCY 38, bd. Suchet 75016 Paris INCIDENT REPORTING SYSTEM Tel. 524.96.93 Telex 630668 AEN/NEA RESTRICTED No.lRS DIFFUS10f4 RESTRElf4TE Title - Titre Seismic Qualification of Safety-Related Systems Date de l 'inciden t 3
Country - Pays Date of Incident September 27, 1981 United' States Type de rdacteur Type of Reactor PWR Plant - Centrale Licensee - Dstenteur du permis d' exploitation Diablo Canyon Pacific Gas and Electric Company M nufacturer - Fabricant Tranche n' Unit N*
y Westinghouse t
Puissance First Commercial Operation -
Power 1084 MWe(net)
Date de mise en. service liot yet Comercial Systems or Components Affected - Systhmes ou composants affectss Containment Building, Auxiliary Building, Piping Runs and Piping Supports in Component Cooling Water System, Residual Heat Removal System, and Auxiliary Feedwater System.
Initial Plant Condition - Etat initial de la tranche Preoperational - Zero Power Wa y in which Incident was Detected ?
Comment l' incident a-t-il 6td d6tects ?
By company engineers during design activity.
Radiation Exposure or Radioactivity Release -
Exposition aux rayonnements ou libstation de radioactivits flone Date of Receipt - Date de idception Date of Distribution - Date de distribution Event description, possible causes, actions taken or planned and lessons learned
- (safety significance of incident) should be included in the following pages.
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Event Description Prior to start of fuel loading in Unit 1, company engineers discovered an error in the engineering diagrams used to locate Vertical Seismic Floor Response (VSFR) Spectra for use in the plant equipment and systems seismic design. This error indicates that some portions of the plant may not satisfy the appropriate seismic design criteria. Fuel had not been loaded before the errors were discovered.
Cause of Event Engineering diagrams for Unit 2 were mistakenly used for analyses of Unit I annulus area. Unit 1 is a mirror image of Unit 2 while the analysis assumed they were identical.
In t.cdition, errors in the diagrams seriously affected the seismic design analyses for some portions of Unit 2.
Subsequent investigation into this issue revealed.
additional design errors indicating a general failing of the licensee's design quality caltrols for service-type contractors.
Reason for Reporting to IRS This event is reportable under criteria 3, "Significant Deficiencies in Design, Construction, Operation, or Safety Evaluation." This event has also been designated an abnormal occurrence for major deficiencies in management controls.
Actions Taken The operating license for Unit 1 was suspended indefinitely on November 19, 1981. New VSFR spectra have been generated and a seismic reverification program has been initiated. This program involves having an independent contractor verify the seismic design of affected systems, piping, equipment,
. mid buildings.
The adequacy of the quality assurance program at Diablo Canyon is under review.by the NRC.
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. 38, bd. Suchet 75016 Paris INCIDENT REPSRTIN'3 SYSTEM Tel. 524.96.93 Telex 630668 AEN/NEA RESTRICTED NO.lRS DIFFUSION RESTREINTE Titre Title Centrifugal Charging Pump (CCP) Miniflow Recirculation Valve Closure Causes CCP to Fluctuate.
Country - Pays Date of Incident - Date de l 'inciden t United States October 22, 1981 Type of Reactor - Type de r6acteur PWR Plant - Centrale Licensee - D6tenteur du permis d* exploitation Trojan Portland General Electric Manufacturer - Fabricant Unit N*
Tranche n*
Wettinghnute Bower - Puissance
.First Co*mmercial Operation 1130 MWe(net)
Date de mise en service 5ll0
' Systems or Components Affected - Systames ou composants affectds CCP miniflow recirculation valve.
Initial Plant Condition Etat initial de la t,t a n ch e From 100% Power to mode 3 after trip Way in which Incident was Detected ?
?
Comment l' incident a-t-il 4td ddtects ?
Operator Observation Radiation Exposure or Racioactivity Release -
Exposition aux rayonnements ou libdration de radioactivitd None Date de rdception Date of Receipt Date of Distribution - Date de distribution Event description, possible causes, actions taken or planned and lessons learned l
[ safety significance of incident) should be included in the following pages.
Description de l' incident, causes possibles, mesures prises ou projet6es et ensei;;nements tir6s (signification de l' incident pour la sGret6) doivent figurer sur les pages suivantes.
O Event Description On October 22, 1981, following a partial loss of plant electrical power and subsequent reactor trip, a Centrifugal Charging Pump (CCP) had to be tripped because the CCP miniflow recirc valve had been closed.
The miniflow recirc valve, M0-8110, had been closed several weeks earlier to increase the "B" CCP charging flow to match the 120 gpm letdown flow. At 1410 on October 22, a reactor trip occurred due to the loss of 12.47 KV bus H1, causing the loss of 4160 V ESF bus Al and a subsequent starting of the "A" emergency diesel generator. The normal shutdown sequencer actuation followed.
This started the "A" CCP.
The "B" CCP was already running. When the "A" CCP was shut off at 1524, charging flow dropped to zero and motor current on the "B" CCP was fluctuating.
The "A" CCP was then restarted and the "B" CCP was tripped.
Tho "B" CCP was later tested satisfactorily.
The apparent cause of the fluctuation was inadequate flow through the "B" CCP due to both pumps operating with M0-8110 closed.
Cause The cause of this event is that normal operating procedures did not explicitly state that the plant should not be operated with M0-8110 closed. However, an Inspection and Enforcement bulletin (80-18) had been issued on July 27, 1980 stating that Westinghouse plants should not close the CCP miniflow recirc valves while in favorable operating conditions (explained in depth in the bull'etin).
Reason for Reporting
~
Because this event is an example of a personne1 error and a procedural deficiency which could result in the loss of plant capability to perform essential safety functions, it is reportable pursuant to criterion 3 "Significant Deficiencies in Design, Construction, Operation, or Safety Evaluation."
Actions Taken Immediate action taken was to turn off the "B" CCP after the motor fluctuations were observed. No problems were noted and the pump performance test was comple-ted without negative results.
The miniflow recirc valve was opened with iristruction not to close it again.
The permanent corrective action includes c requirement in the Operations " Night Orders" that a special watch be posted at the CCP control panel whenever its miniflow valve is isolated. Additionally a precaution warning agains t closing a CCP miniflow valve will be added to the applicable Operating Instructions.
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