05000528/LER-1990-001, :on 900220,radiation Monitor Indication Spike Resulted in ESF Actuation.Caused by Noise in Radiation Monitor Common Ground Circuit & Cognitive Personnel Error. Mod Performed to Circuit & Personnel Counseled
| ML17305A733 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 05/01/1990 |
| From: | Bradish T, James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 192-00655-JML-T, 192-655-JML-T, LER-90-001, LER-90-1, NUDOCS 9005080229 | |
| Download: ML17305A733 (18) | |
text
ACCELERATED DISTRIBUTION DEMONSHRATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9005080229 DOC.DATE: 90/05/01 NOTARIZED:
NO DOCKET FL FACIL:STN-50-528 Palo Verde Nuclear Station, Unit 1, Arizona Publi 05000528 AUTH.NAME i" AUTHOR AFFILIATION BRADISH,T.R.
Arizona Public Service Co.
(formerly Arizona Nuclear Power LEVINE,J.M.
Arizona Public Service Co.
(formerly Arizona Nuclear Power RECIP.NAME RECIPIENT AFFILIATION
SUBJECT:
LER 90-001-01:on 900220,ESF actuation caused by radiation monitor spike.
I 05000528 NOTES'/9 1tr.
DISTRIBUTION CODE IE22T COPIES RECEIVED:LTR ENCL SIZE:
TITLE: 50.'73/50.9 Licensee Event Report (LER), Inciden Rpt, etc.
RECIPIENT Ii3 CODE/NAME PD5 LA PETERSON,S.
INTERNAL: ACNW AEOD/DOA AEOD/ROAB/DS P NRR/DET/ECMB 9H NRR/DET/ESGB 8D NRR/DLPQ/LPEB10 NRR/DREP/PRPB11 NRR/DST/SICB 7E NRR/DST/SRXB 8E RES/DSIR/EIB EXTERNAL EG &G STUART I V ~ A LPDR NSIC MAYS,G NUDOCS FULL TXT NOTES:
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1 RECIPIENT ID CODE/NAME PD5 PD CHAN,T ACRS AEOD/DSP/TPAB DEDRO NRR/DET/EMEB9H3 NRR/DLPQ/LHFB11 NRR/DOEA/OEAB11 NRR/DST/SELB 8D NRRgJ)S
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1 NOTE TO ALL"RIDS" RECIPIENTS:
PLEASE HELP US TO REDUCE WAS'ONTACTTHE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAMEFROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEEDl FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED'TTR 39 ENCL 39
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Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STATION P.O. BOX 52034
~
PHOENIX, ARIZONA85072-2034 JAMES M. LEVINE VICE PRESIDENT NUCI.EAR PRODUCTION 192-00655-JML/TRB/SBJ May 1, 1990 U.
S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555
Dear Sirs:
Subj ect:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 1 Docket No.
STN 50-528 (License No. NPF-41)
Licensee Event Report 90-001-01 File 90-020-404 Attached please find Supplement 1 to Licensee Event Report (LER) No. 1-90-001 prepared and submitted pursuant to 10CFR50.73.
In accordance with 10CFR50.73(d),
we are herewith forwarding a copy of the LER to the Regional Administrator of the Region V office.
If you have any questions, please contact T. R. Bradish, Compliance Manager at (602) 393-2521.
Very truly yours, JML/TRB/SBJ/tlg Attachment CC:
W. F.
Conway J.
B. Martin D.
H.
Coe T. L. Chan A. C. Gehr J.
R.
Newman Inpo Records Center (all with attachment)
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TITLE (4I U.S. NUCLEAR REGULATORYCOMMISSION LICENSEE EVENT REPORT (LER)
APPROVED 0MB NO. 3)504))04 EXPIRES: 4I30I92 ESTIMATED BURDEN PER
RESPONSE
TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50.0 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENTBRANCH (Pt)30). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104), OFFICE OF MANAGEMENTAND BUDGET. WASHINGTON. DC 20503.
PAGE 3
DOCKET NUMBER (2) 0 5
0 0
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Radiation Monitor S ike EVENT DATE(5)
LE R NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED(SI MONTH DAY YEAR YEAR w" SEQUENTIAL M
NUMBER REVI)ION MONTH NUMBER DAY YEAR FACILITYNAMES N/A DOCKET NUMBER(5) 0 5
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THIS REpoRT IS SUBMITTED pURsUANT TO THE RLQUIREMENTB DF 10 cFR (): fcnecc onr or more of tnr foiiowinpf l11) 73.7) (III 73.71)c)
DTHER (specify In Aorrrrct txriowrntf In Trxr, IIRC form 36SAI T.S. 3.3.3e8 ACTION 42.b NAME Thomas R. Bradish, Compliance Manager TELEPHONE NUMBER AREA CODE 6 02 393 -2 521 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
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NO ABSTRACT ILImit to f400 rpecer, Ir., rpproximeteiy fifteen tinpie torte typrwrinen linn) (18)
EXPECTED SUBMISSION DATE IISI MONTH DAY YEAR On February 20,
- 1990, Palo Verde Unit 1 was in Mode 5
(COLD SHUTDOWN) with the Reactor Coolant System at atmospheric pressure and approximately 92 degrees Fahrenheit.
At approximately 0429 MST, the Fuel Building Exhaust Ventilation High Range Radiation Monitor (RU-146) was energized following completion of a modification.
When RU-146 was energized, the Fuel Building Exhaust Ventilation Low Range Radiation Monitor (RU-145) indication increased.
The indication increase initiated the Fuel Building Ventilation Actuation System (FBEVAS) and the Control Room Essential Filtration Actuation System (CREFAS) engineered safety features (ESF).
I The cause of the indication increase was determined to be noise in the radiation monitor's common ground circuit.
A temporary modification was performed to RU-146 to eliminate the circuit noise.
The cause of the ESF actuations was cognitive personnel error in that FBEVAS train "B" was not bypassed prior to performing the modification.
The individual has been counseled and this report will be distributed to maintenance personnel in Units 1, 2 and 3.
This report is also being submitted in accordance with Technical Specification 3.3.3.8 action 42(b) since the radiation monitors were out of service greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
There have been no previous similar events.
NRC Form 388 (54)9)
I I(64)9)
US. NUCLEAR REGULATORYCOMMISSION LICENSEE EVENT REPORT ILER)
TEXT CONTINUATION APPAOVIEO 0MB NO 31500104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER
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OFFICE OF MANAGEMENT AND 8 UDG6 7> WASHINGTON,OC 20503>
FACILITYNAME (I)
DOCKET NUMBER (2)
YEAR LER NUMBER (6) 56006 NTIAL NVM864
.~?4 46VISIQN NIJM664 IIAGE (3)
Palo Verde Unit 1 TEXT ///mort 4/rtto itrtr/Ir>)td. ott tdd>)ior>tl/VRC Form 3/>643/ l)7) 0 5
0 0
0 5
9 0 0 01 01 02 OF 0 7 DESCRIPTION OF WHAT OCCURRED:
A.
Initial Conditions:
On February 20,
- 1990, Palo Verde Unit 1 was in a refueling outage in Mode 5
(COLD SHUTDOWN) with the Reactor Coolant System (RCS)(AB) at approximately 92 degrees Fahrenheit and at atmospheric pressure.
B.
Reportable Event Description (Including Dates and Approximate Times of Major Occurrences):
Event Classification:
Engineered safety feature actuation, and Special Report pursuant to ACTION 42.b of Technical Specification 3.3.3>8 At approximately 0429 MST on February 20,
- 1990, the Fuel Building Ventilation System High Range Radiation Monitor (RU-146)(IL)(MON)
(VI) was energized following completion of a modification.
When the circuit was energized, the Fuel Building Ventilation System Low Range Radiation Monitor (RU-145)(MON)(IL)(VI) indication unexpectedly increased approximately five decades and caused an actuation of the train "B" Fuel Building Essential Ventilation Actuation System (FBEVAS)(VG)(JE).
The designed cross trips of the "A" train FBEVAS and Control Room Essential Filtration Actuation System (CREFAS)(VI)(JE) trains "A" and "B" occurred.
RU-145 and RU-146 work as a pair with the low range monitor (RU-145) normally operating and the high range monitor (RU-146) in standby.
When the low range monitor reaches a predetermined
- setpoint, a
FBEVAS "B" trip signal is generated.
At another predetermined
- setpoint, the high range monitor starts, and the low range monitor goes to standby.
The high range monitor provides tracking of radioactive effluents during postulated accident scenarios.
The high range monitor must be declared inoperable when the low range monitor is inoperable.
Prior to the event, a plant design change was prepared to improve the performance of the Plant Ventilation System High Range Radiation Monitor (RU-144)(IL)(MON)(VL), the Condenser Evacuation System High Range Radiation Monitor (RU-142)(IL)(MON)(SH), and RU-146.
An approved work authorization document (work order) was prepared to implement the design change in RU-146.
The work order for the modification was reviewed by a Instrument and Controls (I&C) maintenance foreman (utility, non-licensed) prior to l
NRC FORM 355A (54)9)
U.S. NUCLEAR REGULATORYCOMMISSION LICENSEE EVENT REPORT ILER)
TEXT CONTINUATION APPROYEO 0MB NO.31504)04 EXPIRES: 4/30/92 ESTIMATED BURDEN PER
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TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 500 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENTBRANCH (P4)30), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104). OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 20503r FACILITYNAME (1)
DOCKET NUMBER (2)
LER NUMBER (5)
YEAR
~<o SEQVENTIAL ORN NV MS E R 2321 REVISION
'I
~ NVMSER PAGE (3)
Palo Verde Unit 1 TEXT /I/more space
/4 redur)ed. ure edd/I/one/HRC Form 35543/()7) o s
o o
o 52 890 0 1 0 1 03 oF 07 implementation.
The work order contained a step that placed FBEVAS "B" in bypass.
The I&C foreman noted that the work order did not effect the operation of RU-145.
Based on his knowledge of the radiation monitoring system and the work order, the I&C foreman elected not to have FBEVAS "B" placed in bypass.
The change to the work order was documented in accordance with plant procedures in the work order.
The modification to RU-146 was completed.
Upon restoration of power to RU-146, the indication of the operational RU-145 increased approximately five decades.
This increase caused the initiation of FBEVAS train "B" which cross tripped FBEVAS train "A" and CREFAS trains "A" and "B". In response to these engineered safety feature actuations, Radiation Protection was contacted and surveys of the fuel building (ND) were initiated.
No unusual radiological conditions were identified.
A control room operator (utility, licensed) secured the normal control room ventilation fans (FAN)(VI) in accordance with the alarm response procedure at approximately 0442 MST on February 20, 1990.
At approximately 0447 MST the control room operator completed equipment actuation verifications.
All operable equipment responded as designed.
FBEVAS train "B" was bypassed at approximately 0449 MST after it was confirmed that RU-145 was not providing a valid indication of radiological conditions.
Subsequently, FBEVAS "A", CREFAS "A",
and CREFAS "B" were reset.
By approximately 0500 MST the normal fuel building and control building ventilation systems (VG)(VI) were returned to service and the control room essential filtration system (VG) and fuel building essential ventilation system (VI) were returned to standby readiness.
In response to the events described
- above, RU-145 was declared inoperable because of the erroneous indication.
Pending implementation of the temporary modification, RU-145, and RU-146 remained inoperable.
The Plant Ventilation System High Range Radiation Monitor (RU-144) also remained inoperable pending resolution of the erroneous indication on RU-145.
RU-144 had been taken out of service at approximately 0051 MST to perform the same modification on the power supply as performed on RU-146.
Therefore, this report is also being submitted in accordance with Technical Specification 3.3.3.8 Action 42(b) and 6'.2 to report an event were the radiation monitors were out of service greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.
Technical Specification 3.3.3.8 Action 42(b) 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> limit for returning RU-144 to service was exceeded at approximately 0051 MST on March 23, 1990.
Technical Specification 3.3 '.8 Action 42(b) 72 hour8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> time limit for NRC Form 355A (509)
NRC FOAM 366A (689)
US. NUCLEAR REGULATOAYCOMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION APPROVED OMB NO. 31500104 EXPIRES: 4/30/92 ESTIMATED BURDEN PEA RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST) 50J) HAS. FORWARD COMMENTS REGAADING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENTBRANCH (F 530), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, ANDTO THE PAPERWORK REDUCTION PROJECT 131504)104).
OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON,DC 20503.
FACILITYNAME (I)
DOCKET NUMBER (2)
LER NUMBER LEI PAGE (3)
YEAR /jr'. SEOVENTIAL NUMBER REVISION NVMSER Palo Verde Unit 1 TEXT /llmort tptct b rtr)rrr)td. Irtttddr)itrM/FVRCForm 3664'4/ (17) 0 5
0 0
0 5
0 0
1 0
1 0 4 OF 0 7 returning RU-146 to service was exceeded at approximately 0226 MST on March 23, 1990.
The Preplanned Alternate Sampling Program (PASP) was initiated in accordance with Technical Specification 3.3.3.8 ACTIONS.
A temporary modification was issued to eliminate the circuit noise in the RU-146 power supply.
On February 23, 1990 at approximately 0307 MST RU-145 and RU-146 were declared operable after completion of the temporary modification.
C.
Status of structures,
- systems, or components that were inoperable at the start of the event that contributed to the event:
Not applicable
- - no structures,
- systems, or components were inoperable at the start of the event which contributed to this event.
D.
Cause of each component or system failure, if known:
There were no component or system failures.
- However, the cause of the erroneous indication on RU-145 was noise generated in RU-146 and conducted through the common ground of the radiation monitor.
The modification to the RU-146 power supply bypassed an inverter/rectifier in order to correct a low voltage condition at the radiation monitors flow transmitter.
The inverter/rectifier contained a filter capacitor that had previously helped eliminate noise in the system.
Therefore, after the modification, some circuit noise was not filtered and caused the radiation monitor erroneous indication.
Failure mode, mechanism, and effect of each failed component, if known:
Not applicable
- - There were no component failures.
For failures of components with multiple functions, list of systems or secondary functions that were also affected:
Not applicable
- - no component failure with multiple functions were involved.I(649)
U S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION APPROVED OMB NO. 31504)104 EXPIRES: 4/30/92 ESTIMATED BURDEN PEA RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REOUEST: 50J) HRS FORWARD COMMENTS REGARDING BURDEN ESTIMATETO THE RECORDS AND REPORTS MANAGEMENTBRANCH (F430). U.S. NUCLEAR REGULATOAYCOMMISSION, WASHINGTON. DC 20555. AND TO THE PAPERWORK REDUCTION PROJECT (31504)104), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON,DC 20503.
FACILITYNAME (1)
DOCKET NUMBER (2)
LER NUMBER I6)
YEAR Sg< SEQUENTIAL gsYc ASyiSION SSUMPEA
.i4 NUMStiS PAGE (3)
TEXT/i/mort sectis ctqti/td, tst tddit'oie/HRC FcNm 366A'4/()2) 0 5
0 0
0 5 2 8 9 0 001 01 05 oF 0 7 For failures that rendered a train of a safety system inoperable, estimated time elapsed from the discovery of the failure until the trains were returned to service:
Not applicable
- - No safety systems were inoperable because of this event.
- However, RU-146 was out of service for approximately 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and 34 minutes, RU-145 was out of service for approximately 70 hours8.101852e-4 days <br />0.0194 hours <br />1.157407e-4 weeks <br />2.6635e-5 months <br /> and 38 minutes, RU-144 was out of service approximately 87 hours0.00101 days <br />0.0242 hours <br />1.438492e-4 weeks <br />3.31035e-5 months <br /> and 29 minutes, and RU-143 was out of service approximately 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br />.
RU-145 and RU-146 were declared operable at approximately 0307 MST on February 23, 1990.
RU-144 and RU-143 were declared operable at approximately 1620 MST on February 23, 1990.
H.
Method of discovery of each component or system failure or procedural error:
Not applicable
- - There were no component or system failures or procedural errors.
Cause of Event
The cause of the radiation monitor high radiation indication was circuit noise as discussed in Section I.D.(SALP Code B).
The design function of the inverter/rectifier was not to filter circuit noise.
Therefore, the increase in circuit noise because of the modification was not anticipated.
The cause of the ESF actuation was cognitive personnel error (SALP Code A) in that FBEVAS Train "B" was not placed in bypass.
An I&C maintenance foreman (utility, non-licensed) reviewed the modification work order in accordance with plant procedures prior to implementation.
The work package contained a step that placed FBEVAS "B" in bypass.
RU-145 provides an actuation signal to FBEVAS B.
The I&C foreman noted that the work order did not effect the operation of RU-145.
Based on his knowledge of the radiation monitoring system and the work instruction, the I&C foreman elected not to have FBEVAS "B" placed in bypass.
This decision was documented in accordance with plant procedures in the work order.
There were no procedural errors or unusual characteristics of the work location which contributed to the event.
NR C Ftim 366A (64) 9
,1 t'I I
NRC FOAM 358A (509)
US. NUCLEAR REGULATORYCOMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION APPAOVEO 0MB NO. 31504)104 EXPIRES: 4/30/92 ESTIMATED BURDEN PER
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TO COMPLY WTH THIS INFOAMATIONCOLLECTION REOUEST: 50.0 HRS, FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENTBRANCH (P430). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (3(504)104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON,DC 20503.
FACILITYNAME ((I DOCKET NUMBER (2)
LER NUMBER (8)
YEAR
/ISAr SEQUENTIAL Pr4r/l AEVOION NUM SA 47: NVMFEA PAGE (3I Palo Verde Unit 1
TEXT ll/md'/N/4 /4 /PI/vlntd, u/4 4ddltlon4/NRC Form 3554'4/ ((2) 0 5
0 0
0 5
9 0 001 0
1 OF J.
Safety System Response:
FBEVAS and CREFAS responded to the spurious signal as designed.
The fuel building normal ventilation was isolated and the normal air handling units (AHU) were stopped.
Train "A" and "B" fuel building essential air ventilation units started to control any release from the building.
The control room normal ventilation isolated and normal air handling units stopped.
Train "A" and "B" control room essential filtration units started.
Failed Component Information
Not applicable
- - There were no component failures.
II.
ASSESSMENT OF THE SAFETY CONSEQUENCES AND IMPLICATIONS OF THIS EVENT:
There were no safety conseq'uences or implications resulting from the CREFAS and FBEVAS actuations.
The Fuel Building Ventilation Monitor detects activity released into the fuel building ventilation.
The radiation monitor performs the safety function of initiating an isolation of normal ventilation systems and activating essential ventilation system on a HIGH-HIGH alarm.
As discussed in Section I.B, there was no indication of abnormal radiation levels at the time of the event.
Additionally, the fuel building was surveyed and no abnormal radiation levels existed.
III.
CORRECTIVE ACTIONS
A.
Immediate The FBEVAS "B" channel was bypassed after it was verified that the initiation signal was not valid.
A temporary modification was performed to the circuit of RU-144 and RU-146 to prevent circuit noise from causing the radiation monitors to indicate erroneously.
B.
Action to Prevent Recurrence:
The I&C maintenance foreman has been counseled on the necessity of placing actuation logic in bypass while working on radiation monitors.
NRC Foim 355A (54)9)
I
NRC FORMSSSA (609)
V.S. NUCLEAR REGULATORYCOMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION APPROVED OMB NO, 3)500106 EXPIRES: E/30/92 ESTIMATED BURDEN PER
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OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503 FACILITYNAME (1)
DOCKET NUMBER (2)
LER NUMBER (6)
PAGE LSI YEAR jul SEQVENTIAI.
NUMBER REVISION NUMBER Palo Verde Unit 1 TEXT ///rrrorp s/Noo itmr/rr/rod, osp pdd4'orM//VRC Forrrr 366A3/ (12) o so o o 528 p
001 01 07 oF P 7 This report will be distributed to the appropriate Units 1, 2, and 3 maintenance personnel.
IV.
Previous Similar Event:
There have been no previous similar events reported pursuant to 10 CFR 50.73.
There have been several previous events attributed to radiation monitor spiking due to noise in the circuit.
- However, none were directly the result of modifying the circuit.
Therefore, recurrence control could not have prevented this event.
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