ML17303A562

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LER 87-015-00:on 870816,control Room Essential Filtration Actuation Initiated on Channels a & B of ESF Actuation Sys. Caused by Spurious Alarm/Trip Signal on Radiation Monitor RU-30.Train B Placed in bypass.W/870903 Ltr
ML17303A562
Person / Time
Site: Palo Verde Arizona Public Service icon.png
Issue date: 09/03/1987
From: Bradish T, Haynes J
ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00273-JGH-T, 192-273-JGH-T, LER-87-015, LER-87-15, NUDOCS 8709170330
Download: ML17303A562 (5)


Text

REGULA Y INFORMATION DISTRIBUTI YSTEM (RIDS)

ACCESSION NBR: 870'7170330 DOC. DATE: 87/09/03 NOTARIZED: NO DOCKET FACIL: STN-50-529 Palo Verde Nuclear Stationi Unit 2i Arizona Publi 05000529 AUTH. NAME AUTHOR AFFILIATION BRADISHi T. R. Arizona Nuclear Pouter Prospect (formerly Arizona Public Serv HAYES'. G. Arizona Nuclear Pouter Prospect (formerly Arizona Public Serv RECIP. NAME RECIPIENT AFFILIATION

SUBJECT:

LER 87-015-00: on 870816'ontrol room essential filtration actuation initiated om Channels A 5 B pl- ESF -actuation sys.

Caused by spurious alarm/trip signal on radiation monitor RU-30. Train B placed in bypass. W/870'703 ltr.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR i ENCL TITLE: 50. 73 Licensee Event Report (LER)i Incident g

Rpti SIZE:

etc.

NOTES: Standardized plant. 05000529 REC IP IENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 LICITRAiE 1 1 DAVIS' 1 INTERNAL: ACRS MI CHELSQN 1 1 ACRS MOELLER AEOD/DOA 1 AEOD/DSP/NAS 1 1 AEOD/DSP/RQAB 2 2 AEOD/DSP/TPAB 1 DEDRQ 1 NRR/DEST/ADS 0 NRR/DEST/CEB 1 NRR/DEBT/ELB 1 1 NR 8 /DE ST/ I C SB 1 NRR/DEST/MEB 1 NRR/DEST/MTB 1, 1 NRR/DEST/PSB 1 1 NRR/DEST/RSB 1 1 NRR/DEST/SGB 1 NRR/DLPG/HFB 1 1 NRR/DLPG/GAB NRR/DQEA/E*B 1 NRR/DREP/RAB 1 P PB NRR/PMAS/ ILRB 1 EG F - 02 1 RES DEPY GI 1 1 RES TELFQRDi J 1 1 RES/DE/EIB 1 RGN5 FILE 01 1 EXTERNAL: EGS.G GROHi M 5 5 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRIS' 1 1 NSIC MAYSi G 1 1 NOTES:

TOTAL NUMBER OF COPIES REQUIRED: LTTR 45 ENCL 44

NAC Form 344 UA. NUCLEAR REOULATORY COMMISSION (9 03l APPROVED OMB NO. 3)500104 EXPIAES: 4/31(IS LICENSEE EVENT REPORT ILER)

FACILITY NAME (I) DOCKET NUMBER (2) PA Palo Verde Unit 2 0 5 0 0 0 2 1 OF 0 ESF Actuation Caused By Spurious Alarm/Trip Signal on Radiation Monitor RU-30 EVENT DATE (5) LER NUMBER IS) REPORT DATE (7) OTHER FACILITIES INVOLVED(SI SEOVENTIAI. "'Ytcx DAY YEAR FACILITY NAMES POCKET NUMBER(El MONTH DAY YEAR YEAR NVMSEII g'r'yrS NVMSEII MONT~

N A 0 5 0 0 0 1 6 8 7 8 7 0 1 5 PO 09 7 N A 0 5 0 0 0 THIS AEPOAT IS SUBMITTED PURSUANT TO THE REDUIAEMENTB oF 10 cFR g; (cneco one or more ol tne lollowlnpl (11)

OPERATINO MODE ( ~ ) 20. c02 lb) 20.404(el 50.73(c l(2)(iv) 73.71(II)

I(1)(ill) 20.405( ~ I(1) IB SOM(el(I) 50.73(c) (2)(vl 73.71(cl POWER LEVEL 1 p p 20.405( ~ I (I) I 4) 50.34lc)(2) 50.7 34) (2 I (rQ) OTHER ISpecily ln Abttrect belOw end ln Text, HRC Form 20.405( ~ 50.73( ~ I (2) Il) 50.73(el(2)(rill) (Al SFSAI 20AOS Ic III l(lvl 50.7')(2)(5) 50.73(e) (2) (rIEI(SI 20.405( ~ I (I I Iv) 50.73(c) (2)(ill) 50.73(c) (2)(xl LICENSEE CONTACT FOR THIS LEA (12)

NAME TELEPHONE NUMBER AREA COPE Thomas R. Bradish, Compliance Supervisor 602 393- 353 1 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRI ~ EP IN THIS REPORT (13)

SYSTEM COMPONENT MANUFAC EPORTASLE COMPONENT MANUFAC. EPOATABLE CAUSE TURER TO NPADS CAUSE SYSTEM TURER TO NPRDS kwhr%

SUPPLEMENTAL AEPORT EXPECTED IICI MONTH DAY YEAR EXPECTED SUS MISS ION YES Illyet, complete EXPECTED SUStrttSSIOH DATE)

AssTRAcT (Limit to fe00 tpecet, leepproxlmete!y Bitten clnole tpece typewritten linnl (14)

NO PATE (15) 11 1587 On August 16, 1987 at 0609 MST, Palo Verde Unit 2 was in Mode 1 (POWER OPERATION) at 100 percent power when a Control Room Essential Filtration Actuation (CREFAS) was initiated on Channels A and B of the Engineered. Safety Features Actuation System (ESFAS).

The actuation was in response to a spurious alarm/trip signal on the "B" Control Room Ventilation Intake Noble Gas Monitor (RU-30), and occurred coincident with an attempt to reset a local alarm on the subject monitor with a p'ortable indication and control unit (PIC). An investigation is currently in progress to determine the cause of the event, which will include an evaluation to determine if utilization of the PIC was a contributing factor. The results of the investigation will be provided in a supplement to this report.

As immediate corrective action, the actuated equipment was returned to a normal operations configuration, and the Train "B" CREFAS was placed in bypass pending further evaluation.

Other events involving CREFAS actuations have been reported, however, these events did not involve the sequence of activities noted above and are not considered similar events.

87091 70330 870903 PDR ADOCK 05000M9 8 PDR NRC farm 344

NAC Forrrr 355A U.S. NUCL'EAR AEOULATORY COMMISSION 1583 I LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPAOVEO OMS NO 3150W105 EXPIRES: SISI/IE!

FACILITY NAME 11I OOCIIET NUMSEA 13)

LEA NUMSEA ISI ~ AOE 131 SEOVENTIAL NVM ER "

gju REVISION NVM 51 Palo Verde Unit TEXT Of mure 5PPIP 15 PIFIPPIE u55 2

r551enV HAC %%drrrr 3NA'IlII Tl 0 s 0 0 o 529 87 015 0 0 02oF0 3 On August 16, 1987 at 0609 MST, Palo Verde Unit 2 was in Mode 1 (POWER OPERATION) at 100 percent power when a Control Room Essential Filtration Actuation (CREFAS)" was initiated on Train "B" of the Engineered Safety Features Actuation System (ESFAS)(JE). The Train "B" CREFAS cross-tripped the Train "A" CREFAS, per design, and all associated equipment operated satisfactorily. The CREFAS was initiated by the "B" Control Room Ventilation Intake Noble Gas Monitor (RU-30)(IL)(RI). The actuations were identified by the control room operators (utility-licensed) as a result of main control board (MCBD) annunciations '(ANN).

Following the ESF actuations, the control room operators (utility-licensed) verified that there were no actual radiation level increases by comparing the RU-30 results to the "A" Control Room Ventilation Intake Noble Gas Monitor (RU-29)(IL)(RI), and by determining that, coincident with the event, a radiation protection (RP) technician (utility-non-licensed) had reset the local alarm on RU-30 by utilizing a portable indication and control unit (PIC)(HIC) with the monitor placed in LOCAL mode.

Based on the above information, the shift supervisor (utility-licensed) determined the alarm/trip to be spurious. At 0622 MST the control room operator (utility-licensed) reset the CREFAS "A" and "B" alarms and the Train "B" CREFAS actuated equipment, and placed the Train "B" CREFAS in bypass pending further investigation. At'634 MST, the shift supervisor (utility-licensed) directed the control room operators (utility-licensed) to reset the Train "A" CREFAS actuated equipment, and at 0712 MST the event was secured. The total duration of the event was approximately 66 minutes.

Subsequent investigation revealed that, prior to the event, the Control Room notified the Radiation Protection office that the local alarm (ALM) on radiation monitor RU-30 was on. The RP technician (utility non-licensed) then verified that RU-30 was not registering an alarm condition on the Display and Control Unit (DCU)(AIC) located in the RP office, and that the specified setpoints (e.g., 2.0 X E-5 micro Curie [Ci]/cubic centimeter [cc]) were in the monitor.

The RP technician then notified the Control Room that the RU-30 local alarm would be reset with a PIC. The reset is accomplished by connecting the PIC to the monitor, switching the PIC from REMOTE to LOCAL mode, and depressing the "ALARM ACK" button. These actions were completed, however, following the alarm reset the PIC may have been disconnected from the radiation monitor while in LOCAL mode. Procedural controls require the PIC to be switched to-REMOTE mode prior to being disconnected from the monitor. This action is believed to have caused a voltage spike on the radiation monitor, which in turn generated a spurious alarm/trip signal.

4IIC IOIIM 555A 15 53>

NRC Form 344A U.S. NUCLEAR REOULATOIIY COMMISSION

<943 I LICENSEE EVENT REPORT (LERI TEXT CONTINUATION API'ROYEO OMS NO 3<40M<94 EXPIRES: S/3<I<6 FACILITY NAME <II OOCKET NUMSEII <El LER NUMSER <SI PACE <3)

II SEQUENTIAL o 4 v I4 IO rr YE A HUM 4R rr<rM to Palo Verde Unit TEXT Nmort 2

totct S ttrrttrE rrto edknonel ArRC Ann 3<E<ASI IITI 0 5 0 0 0 529 87 015 00 03 QF 0 3 The assessment of the event as a spurious alarm/trip was substantiated when, following the event, the RP technician found the alarm/trip setpoint for RU-30 to be at the default value (2.2 X E-6 micro Ci/cc) in lieu of the specified value noted above. The remote indication and control unit (RIC)(AIC) normally downloads the speciiied setpoints to the radiation monitor, however, the default setpoints will be downloaded if the specified values are lost due to a voltage fluctuation or electronic circuit noise.

An investigation is currently in process to determine the cause of the event, which will include an evaluation to determine if utilization of the PIC was a contributing factor. The results of the investigation will be provided in a supplement to this report.

As corrective action the monitor was reset, returning the setpoints to the specified values, and the Train "B" CREFAS returned to service. Corrective action to prevent recurrence will be determined and implemented upon completion of the pending investigation.

Based on the information noted above, no personnel errors have been identified at this time which contributed to the event. No procedural errors contributed to the event, and no structures, systems or components inoperable prior to the event were identified as contributing factors. Based on the actions described above, which included verification that no abnormal radiation levels existed pursuant to the event, there was no effect on the health and safety of the public and no safety impact on the unit. Other events involving CREFAS actuations have been reported, however, these events did not involve the sequence of activities noted above and are not considered similar events.

4IIC l OR>> 344k

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Arizona Nuclear Power Project P.O, BOX 52034 ~ PHOENIX, ARIZONA 85072-2034 192-00273-JGH/TRB/KCP September 3, 1987 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 2 Docket No. 50-529 Licensee Event Report 2-87-015-00 File: 87-020-404

Dear Sirs:

Attached please find Licensee Event Report (LER) No. 2-87-015-00 prepared and submitted pursuant to 10CFR 50.73. In accordance with 10CFR 50.73(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 Supervisor at (602) 393-3531.

Very truly yours, a~2 +

J. G. Haynes Vice President Nuclear Production JGH/KCP/cld Attachment cc: 0. M. DeMichele (all w/a)

E. E. Van Brunt, Jr.

- J. B. Martin R. C. Sorenson

,E. A. Licitra A. C. Gehr INPO Records Center