05000530/LER-1990-001, :on 900127,spurious Train B Containment Purge Isolation Actuation Signal Initiated on Balance of Plant Esfas.Caused by Spiking of Radiation Monitor RU-38 Due to Malfunctioning Central Processing Unit
| ML17305A560 | |
| Person / Time | |
|---|---|
| Site: | Palo Verde  |
| Issue date: | 02/23/1990 |
| From: | Bradish T, James M. Levine ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| 192-00634-JML, LER-90-001, NUDOCS 9003080076 | |
| Download: ML17305A560 (12) | |
| Event date: | |
|---|---|
| Report date: | |
| Reporting criterion: | 10 CFR 50.73(e)(2) |
| 5301990001R00 - NRC Website | |
text
1 ACCELERATE3 wL~)UBUTION DEMONS TION SYSIEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)
ACCESSION NBR:9003080076 DOC DATE: 90/02/23 NOTARIZED: NO DOCKET 4N FACIL:STN-50-530 Palo Verde Nuclear Station, Unit 3, Arizona Publi 05000530 AUTH.NAME 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
/
05000530 A
NOTES:Standardized plant.
SUBJECT:
LER 90-001-00:on 900127,inadvertent containment purge ESF actuation.
W/8
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TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.
RECIPIENT ID CODE/NAME PD5 LA PETERSON,S.
INTERNAL: ACNW AEOD/DOA AEOD/ROAB/DSP NRR/DET/ECMB 9H NRR/DET/ESGB 8D NRR/DLPQ/LPEB10 NRR/DREP/PRPBll NRR/DST/SICB 7E NRR/DST/SRXB 8E RES/DSIR/EIB COPIES LTTR ENCL 1
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1 RECIPIENT ID CODE/NAME PD5 PD ACRS AEOD/DSP/TPAB DEDRO NRR/DET/EMEB9H3 NRR/DLPQ/LHFB11 NRR/DOEA/OEAB11 NRR/DST/SELB 8D NRRQSISR/SPLBB D1 EG FIL 02 RGN5 FILE 01 COPIES LTTR ENCL 1
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PLEASE HELP US TO REDUCE WASIEI CONI'ACI'.DOCUMENTCONIROL DESK, ROOM PI-37 (EXT. 20079) TO MiMNA'IEYOUR NAMEPROM DISIRIBUTION LISIS FOR DOCUMENTS YOU DEPT NEEDI FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED:
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Arizona Public Service Company PALO VERDE NUCLEAR GENERATING STA~'AN P.O. BOX 52034
~
PHOENIX. ARIZONA89" 192-0('
'WDAJ Februa;y 0
'U. S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555
Dear Sirs:
Subj ect:
Palo Verde Nuclear Generating Station (PVNGS)
Unit 3 Docket No.
STN 50-530 (License No. NPF-74)
Licensee Event Report 3-90-001 F
e 90-0 0-404 Attached please find Licensee Event Report (LER) No. 90-001-00 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, (Acting) Compliance Manager at (602) 393-2521.
Very truly yours, JML/TRB/DAJ/k]
Attachment ccI W. F.
Conway E.
E. Van Brunt J.
B. Martin D. H.
Coe T. L. Chan A. C. Gehr J.
R.
Newman INFO Records Center (all with attachment) 08007(~
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FACILITYNAME (I)
DOCKET NUMBER (2)
PAGE 3
Palo Verde Unit 3 TITLE (4)
Inadvertent Containment Purge ESF Actuation o
5 o
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LER NUMBER (6)
REPORT DATE (7)
OTHER FACILITIES INVOLVED(8)
MONTH DAY YEAR YEAR SEDVKNTIAL NUMBER yw'i REVISION 64$ NVMSKR MONTH OAY YEAR N/A FACILITYNAMES DOCKET NUMBERIS) 0 5
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LICENSEE CONTACT FOR THIS LER (12) 0 THE ALDUIREMENTSOF 10 CFR (). (Check onr or more ol thr lollowinpl(Ill THIS REPORT IS SUBMITTED PURSUANT T 73.71(II) 73.71(cl OTHER ISprcilyin Abstirct below end ln Text, H>IC Form 368Al NAME Thomas R. Bradish, (Acting) Compliance Manager TELEPHONE NUMBER AREA CODE 60 23 93 -2 5 21 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)
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On January 27, 1990, at approximately 2248 MST Palo Verde Unit 3 was in Mode 1
(POWER OPERATION) at approximately 60 percent power when a spurious Train HB" Containment Purge Isolation Actuation Signal (CPIAS) was initiated on the Balance of Plant Engineered Safety Features Actuation System.
The Train HBin CPIAS resulted in the designed cross-trips of Train "A" CPIAS and Train "A" and "BH Control Room Essential Filtration Actuation Signals (CREFAS).
The actuations occurred when the Train "B" Power Access Purge Area Radiation Monitor (RU-38) spiked above its High-High alarm/trip setpoint.
At the time of the event, all Containment Purge System isolation valves were closed as no containment purge was in progress.
All components in the Control Room Essential Filtration System responded properly to the CREFAS.
Radiation Protection personnel verified that no abnormal radiation levels existed in the vicinity of RU-38.
Additionally, analysis of a gas sample collected from the Plant Vent exhaust indicated no abnormal activity levels.
The cause of RU-38 spiking was malfunctioning Central Processing Unit and Random Access Memory boards.
As corrective action, the boards have been replaced with newer models.
There have been no previous similar events.
NRC Fotsn 366 ($4)9)(6691 U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT ILERI TEXT CONTINUATION APPROVED OMB NO.31500104 EXP(A ES: 4(30/92 ESTIMATED BURDEN PEA AESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST( 500 HASE FORWARD COMMENTS REGARDING BUAOEN ESTIMATE 'TO THE RECORDS ANO REPORTS MANAGEMENTBRANCH (F630). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK AEDUCTION PROJECT (3(500104).
OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON,OC 20503, FACILITYNAME (11 DOCKET NUMBER (21 LER NUMBER (61 PAGE (31 YEAR P@C SEQVENTIAI gN NVMSER RRS REVISION NUMBER Palo Verde Unit 3 TEXTillIR(ee <<>>ee ie reqeeed, we eddiooI>>l ill(CFeeoI 35643( OT(
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o 5 30 900 0 100 02 OF DESCRIPTION OF WHAT OCCURRED:
Initial Conditions:
On January 27, 1990, at approximately 2248 MST Palo Verde Unit 3 was in Mode 1 (POWER OPERATION) at approximately 60 percent power.
B.
Reportable Event Description (Including Dates and Approximate Times of Major Occurrences):
Event Classification:
Engineered Safety Feature Actuation At approximately 2248 MST on January 27,
- 1990, a spurious Train "B" Containment Purge Isolation Actuation Signal (CPIAS)(VA)(JE) was initiated on the Balance of Plant Engineered Safety Features Actuation System (BOP ESFAS)(JE).
The Train "BR CPIAS resulted in the designed cross-trips of Train "AR CPIAS and Train "AN and NB" Control Room Essential Filtration Actuation Signals (CREFAS)
(VI)(JE).
The actuations occurred when the Train "B" Power Access Purge Area Radiation Monitor (RU-38)(VA)(IL)(RI) spiked above its High-High alarm/trip setpoint.
At the time of the event, all Containment Pur e System isolation valves (VA)(ISV) were closed as no containment purge was in progress.
All components in the Control Room Essential Filtration System (VI) responded properly to the CREFAS.
Radiation Protection personnel (utility, non-licensed) verified that no abnormal 'radiation levels existed in the vicinity of RU-38.
Additionally, analysis of a gas sample collected from the Plant Vent (VL) exhaust indicated no abnormal activity levels.
The BOP ESF actuation resulted in close signals being sent to all Train "A" and "B" Containment Purge System isolation valves and actuations of the Control Room Essential Ventilation System (VI)
Trains "A" and "B", the Essential Chilled Water System (KM) Trains "A" and "B", the Essential Cooling Water System (BI) Trains "A"
and "B", and the Essential Spray Pond System (BS) Trains "A" and NBA'llcomponents operated as designed.
The BOP ESF actuations were identified by Control Room personnel (utility, licensed) as a result of main control board (MCBD) annunciations (ANN).
There were no operator actions which contributed to the cause 'of the event.
No other ESF actuations occurred and none were necessary.
Unit 3 personnel (utility, licensed and non-licensed) verified that the ESF actuations did not occur as a result of high radiation levels in the Containment N AC FoRR 366A (689)
i'
NAC FORM358A (54(9I U.S. NUCLEAR AEGULATORYCOMMISSION LICENSEE EVENT REPORT (LER)
TEXT CONTINUATION APPROVEO 0MB NO.31500104 EXPIRES I 4/30/92 ESTIMATED BURDEN PER
RESPONSE
TO COMPLY WTH THIS INFORMATION COLLECTION AEOUEST( 50.0 HRS. FORWARD COMMENTS REGARDING BUAOEN ES'TIMA'TE TO '(HE RECORDS ANO REPORTS MANAGEMENTBRANCH IP4(30I. U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500I041. OFFICE OF MANAGEMENTANO BUDGET, WASHINGTON,OC 20503.
FACILITYNAME (I)
DOCKET NUMBER (2l LER NUMBER IBI YEAR X/KI ffQVfNTIALC>o'fyISIOII ro?e NVM fA HAII NVMofrl PAGE (3)
Palo Verde Unit 3 TEXT/Ifmore feece /4 reev/red, voe ocAWonel /IRC Fomr 3554'4/ I Ill o
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Status of structures,
- systems, or components that were inoperable at the start of the event that contributed to the event:
No structures,
- systems, or components, were inoperable at the start of the event which contributed to the event.
D.
Cause of each component or system failure, if known:
Troubleshooting performed in accordance with an approved work authorization document and an engineering root cause of failure investigation determined that the cause of the RU-38 spiking problem was malfunctioning original equipment Central Processing Unit (CPU) and Random Access Memory (RAM) boards in RU-38's microprocessor (CPU).
Further determination of the cause of the board malfunctions will not be performed since the original equipment boards have been replaced by newer mod'els.
The newer models were developed to improve the high temperature performance of circuit boards in similar monitors located in higher temperature environments.
The new models have improved high temperature performance and are expected to improve overall performance.
However, circuit board malfunction may still occur and APS has not established that using the new model boards will reduce the incidence of ESF actuations.
Due to the anticipated improvement in performance, the new model replacement boards are being installed in other similar radiation monitors consistent with parts availability and need to perform work which requires board replacement.
Failure mode, mechanism, and effect of each failed component, if known:
The malfunctioning CPU and RAM boards in RU-38's microprocessor resulted in the output of RU-38 spiking high.
The spike was above the High-High alarm/trip setpoint for actuating a Train AA" CPIAS and subsequent ESF actuation signals as described in Section I.B.
F.
For failures of components with multiple functions, list of systems or secondary functions that were also affected:
Not applicable
- - RU-38 does not have multiple functions.
NRC ForoI 356A (589)
0
NRC FORM 355A (889)
U.S, NUCLEAR AEQULATORYCOIOMISSION LICENSEE EVENT REPORT {LERI TEXT CONTINUATION APPROVED @ MB NO. 31500)04 EXPIRES'. O/30/92 ESTIMATED BURDEN PEA RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 500 HRS, FORWARD COMMENTS REGARDING BVADENESTIMATE TO THE RECORDS AND AEPORTS MANAGEMENTBAANCH (P430), V.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON. OC 20555, AND TO THE PAPERWORK AFOVCTION PROJECT (3)500)OOI. OFFICE OF MANAGEMENTAND BUDGET,WASHINGTON.OC 20503.
FACILITYNAME (ll DOCKET NUMBER (2)
YCAR LER NUMBER (5)
SCQUCNTIAL NUMOCR REVISION NUMCCR PAGE. LT)
Palo Verde Unit 3 TEXT ///mom J/>>co /o toOowaL ooo PIA//o(n>>//YRC Form 35858/ (IT) o so o o 5 30 90 0 0 1
0 0 0 4 QF 0 G.
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
- - the malfunction in RU-38 did not render a train of a safety system inoperable.
RU-38 was declared inoperable at approximately 2248 MST on January
'27, 1990.
Following troubleshooting and replacement of the malfunctioning CPU and RAM boards, RU-38 remained out of service in order to perform scheduled 18-month surveillance testing.
Testing was satisfactorily completed and RU-38 was returned to service at approximately 1556 MSt on February 2,
1990.
RU-38 was inoperable approximately five (5) days seventeen (17) hours.
H.
Method of discovery of each component or system failure or procedural error:
The malfunctioning CPU and RAN boards in RU-38 were discovered during troubleshooting performed in accordance with an approved work authorization document.
There were no procedural errors discovered.
Cause of Event
The cause of the event was malfunctioning CPU and RAN boards in RU-38 as described in Section I.D (SALP cause classification-equipment failure).
Safety System Response:
The following automatic safety system responses occurred:
Control Room Essential Ventilation Essential Chilled Water System Essential Cooling Water System Essential Spray Pond System K.
Failed Component Information
Power Access Purge Area Radiation Monitor RU-38 was manufactured by Kaman Scientific Corporation.
The malfunctioning CPU board is part number 451497 Rev.
A and the malfunctioning RAM board is part number 451498 Rev.
A.
NRC Form 355A (889)(649).
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US. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT {LER)
TEXT CONTINUATION APPROVED OMB NO,31500)0S EXPIRFS: S/30/92 ESTIMATED BURDEN PER
RESPONSE
TO COMPLY WTH THIS INFORMATION COLLECTION REOUEST: 500 HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TD THE RECORDS AND REPORTS MANAGEMENTBRANCH (P430). V.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555. AND TO THE PAPERWORK RFOVCTION PROJECT (31504104),
OFFICE OF MANAGEMENTANO BUDGET,WASHINGTON, DC 20503.
FACILITYNAME (1)
DOCKET NUMBER (2)
YEAR LER NUMBER (6)
Sl(e( sBOUBNTIAL
'C8 NUM S A
'..(j ASVISION
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II.
ASSESSMENT OF THE SAFETY CONSEQUENCES AND IMPLICATIONS OF THIS EVENT:
There were no safety consequences or implications resulting from this event.
The Train "B" Power Access Purge Area Radiation Monitor (RU-38) is located outside the containment (NH) near the power access purge exhaust and refueling purge exhaust ducts (VA)(DUCT).
RU-38 monitors the ducts for purged airborne radioactivity concentrations that could potentially result in off-site doses exceeding 10CFR100 limits.
RU-38 performs the safety function of monitoring purge exhaust and initiating a High-High dose rate alarm initiation signal to BOP ESFAS which performs the safety function of shutting the Containment Purge System isolation valves, activating Control Room Essential Ventilation, and starting necessary support system (See Section I.J).
As discussed in Section I.B, Unit 3 personnel verified that no actual high radiation levels existed.
Additionally, Containment Purge System isolation valves were shut at the time of the event.
III.
CORRECTIVE ACTIONS
A.
Immediate As immediate corrective action, Unit 3 personnel verified that no high radiation levels existed as described in Section I.B.
B.
Action to Prevent Recurrence:
As action to prevent recurrence, the malfunctioning CPU and RAM boards were replaced with newer model boards.
IV.
PREVIOUS SIMILAR EVENTS
There have been no previous similar events reported pursuant to 10CFR50.73 which resulted from a malfunction of the Power Access Purge Area Radiation Monitors'PU and RAN boards.