ML17300A788

LER 87-001-00:on 870328,while Preparing to Enter Mode 6, Control Room Essential Filtration Actuation Signals & Containment Purge Isolation Actuation Signals Received.Cause Under investigation.W/870424 Ltr

ML17300A788
Person / Time
Site:	Palo Verde
Issue date:	04/24/1987
From:	Bradish T, Haynes J ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00195-JGH-T, 192-195-JGH-T, LER-87-001-02, LER-87-1-2, NUDOCS 8705040003
Download: ML17300A788 (10)

Text

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A(>>CESSION NBR: 8705040003 DGC. DATE: 87/0+/24 NOTAR I ZED: NG'OCKET li

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FACII: BTN-50-530 Pal o Verde Nuclear Station> Uni t 3> Ari zona Pub 05000530 AUTH. NAMF; AUl HGR AF'F I L I AT ION BRADISH> T. R. Ari zona Nuclear Poi"er Prospect (Forme,"li! *rizona Public Serv HAYNES> J. Q. Ari z ona Nuc lear Power Pro Ject ( Fora~> rig Ar i zona Pub 1 i c Serv REC I P NAME RFC IP I ENT AFF I L I*iI GN SUB JEC'}': LER S7-001-00: on 87032S> uhile preparing to enter Mode 6>

control room essential Filtratior actuation ignals b c

'ontainment pur q e i so 1 at i on actuation s i gna s T ec e i ved. Cause 1 under investigation. W/870':24 ltr.

DISTR IS1>TION CODE: IEEED COPIES RECEIVED: LTR } ENCL 3 etc.SIIE:

TITLE: 50. 73 Licensee Event Report (LF'R) Incident Rpt> >

NOTES: Btandardi z ed p 1 ant. l'l. Davis NHR: 1CiJ. 05000530 REC I P I EN'l CGP IEB RECIPIENT CGP IEB ID COD=-/NAME L l TR ENCL ID CODE/NA~i:- LTTR E"'L, L l>D5 LA 1 PD5 PD

t. ICI TRA E J 1 DAVIS M 1 INTERNAL: ACRB i'lICHELBON J 1 AC R S MiOELLE R 1 1 AEGD/DQA J 1 AEGD/DSP/ROAB 2 AEOD/DSP/TPAB J 1 r.'RR/DEBT/ADE ;I. 0 NRl>>/DEBT/ADS 0 ERR/DEST/CEB 1 NRR/DEBT/EL1>> J r:.~R/DEBT/ I CSI>> 1 NRR/DE..>T/MFJ>> 1 t!RP /DEST/MTB 1 igRR/DEBT/PBB>> J 1 t'!RR/DEBT/RSB 1 NRR/DEBT/BOB>> t':F(~/DLPG/HFB 1 1 NR R/DLP 6/8<'I>> J NRR/DOEA/EAB 1 NRn/DREP/Erl>> J 1 ttRR/DREP/R*B 1 i.

i!RR/DREP/RPB  ? t-' I LRI>> 1 NRR/PMAB/F>TBL>> J EC FILE (i>":: 1 1 t<FB BPF IB, t RGN5 F I LE 1 L

EXTERNAL:  !.=C-'8(Q QROH> l'l 5 H ST LOBB Y WhAP t F>DR t!RC PDR t~>BlC HARRIS } 1 t>!SIC I"lAYS> G NOTES:

TOTAL NUi>'>BER OF COP IES REGUIRED: LTTR 43 ENCL

i' NAC Form 344 US. NUCLEAR AEOULATORY COMMISSION (94)3)

APPAOVED OMS NO. 31504104 LICENSEE EVENT REPORT (LER) EXPIRES: SI31ISE FACILITY NAME (II 'OCKET NUMSER (2) PA E Palo Verde Unit 3 0 5 0 0 0 5'3 0 1 OFO TITLE ici En ineered Safet Feature Actuation EVENT DATE(5) LER NUMSER (5) REPORT DATE (7I OTHER FACILI'TIES INVOLVED (SI MONTH OAY YEAR YEAR SEovENTIAL :~k "EYR~ DAY YEAR FACILITYNAMES DOCKET NUMSER(S)

NVMEEtr '.err NVMEER MONTH N A 0',5 0 0 0 0 3 2 8 8 7 8 7 0 0 1 00 04 2487 N A 0' 0 0 0 OPERATINO THIS REPORT IS SUSMI'TTED PURSUANT TO THE REOUIREMENTS OF 10 CFA (I: ICneck one or more of tne Iollovnnci II'll MODE I~ ) N 20.402(tr) 20AOS(cl 50.7 3(e) (2) (iv) , 7$ .71(tr)

POWER 20.405( ~ l(1 I (II 50.34(cl(1) 50.73(el(2) lv) 7$ .71(cl LEVEL p p p 20.405(e l(1) (ii) 50.34(c) (2) 50.73(e) (2)(vE) OTHER ISpecllp ln Aettrect treiovr end in 7eeL HI) C Form 20.405(e I ) I I (it i) 50.73( ~ ) LT I(i) 50.73(el(2)(viiil(AI J66AI 20A05(el)1)(ivl 50.73(eHEI(iil 50.73( ~ )(2)(v(Q) IS) 20A05 (4) II I(vl 50.73(e) (21(liil 50.73( ~ ) (2)(e)

I ICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NVMSER AREA CODE T. R. Bradish Com liance Su ervisor Ext. 6936..

COMIILETE ONE LINE FOR EACH COMPONENT FAILURE DESCAI ~ ED IN THIS REPORT (13I 60 2932 530 0 CAUSE SYSTEM COMPONENT MANUFAC REPOATASLE MAHUFAC EPORTASLE TURER TO NPRDS COMPONENT TVRER TO HPRDS

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kM+N"'.~'o(KN SUPPLEMENTAL REFORT EXPECTED (141 MONTH DAY YEAR EXPECTED SVSMISSIOH YES ill vet, Cemplete EXPECTED SUSMISSIOIY DATEI ASSTAACT (Limit to te00 totcet, l.e.. epproelmeterrr lirteen tincle tpece tvpenrinen lr'nevi (14)

NO DATE (15 I 0 629 87 At approximately 1301 MST on March 28, 1987, Palo Verde Unit 3'as preparing to enter Mode 6 (Refueling) when Control Room Essential Filtration Actuation Signals (CREFAS) and Containment Purge Isolation Actuation Signals (CPIAS) were received on both channels of the Balance of Plant Engineered Safety Features Actuation System (BOP ESFAS). These BOP ESFAS actuations were annunciated in the control room on the main control board. All associated equipment responded as designed. Control room personnel secured'll actuated equipment in accordance with approved procedures by 1413 MST on March 28, 1987. Both channels of CREFAS and CPIAS were unavailable for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> .and 12 minutes.

At approximately 1301 MST,, immediately prior to the BOP ESFAS actuation, a "DISTR PNL 26 AC UNDV/GND" trip was received on distribution panel 26 and "120VDC INV B AC/DC STATUS" trouble alarm was received for inverter "BHe As designed, the static transfer "switch automatically transferred from the "B" inverter to the 120 VAC voltage regulator. Immediately following the static transfer switch operation, both channels of CREFAS and CPIAS were actuated on the BOP ESFAS system.

The root cause of this event is currently under investigation. A supplement to this LER will be submitted following the completion of the investigation.

8705040003 870424 rj.l n)2 PDR ADOCK 05000530 PDR

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NRC form OSSA U.S, NUCLEAR REGULATORY COMMISSION I9 SSl LICENSEE EVENT REPORT ILER) TEXT'CONTINUATION APPROVED OMS NO 31SOWIOO EXPIRES: SI31/SS PACILITV NAME I11 DOCKET NUMSER (ll LER NUMSER (Sl ~ AOE IS)

YEAR SEOUENTIAL rl'IV IS IO N N VMS K rl NUMPEII Palo Verde Unit 3 o s o o o 5 3 0 8 7 0 0 1 00 02 OF 0 3 TEXT illmoro Ipocoio oqrrired, voo prrrMiiooliVRC irorrrr SSSATU I ITI At approximately 1301 MST'n March 28, 1987, Palo Verde Unit 3 was preparing to enter Mode 6 (REFUELING) when Control Room Essential Filtration Actuation Signals (CREFAS)(JE) and Containment Purge Isolation Actuation Signals (CPIAS)

(JE) were received on both channels of the Balance of Plant Engineered Safety Features Actuation System (BOP ESFAS)(JE). These BOP ESFAS actuations were annunciated in 'the control room on the main control board (MCBD). All associated equipment responded as designed. Control room personnel (utility= licensed) secured al'1 actuated equipment in accordance with approved procedures by 1413 MST on March 28, 1987. -Both channels of CREFAS and CPIAS were unavailable for 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and 12 minutes.

At approximately 1301 MST, immediately prior to the BOP ESFAS actuations, a "DISTR PNL 26 AC UNDV/GND" trip was received on distribution panel (EF, PL) 26 and "120VDC INV B AC/DC STATUS" trouble alarm (AIM) was received for inverter "B" (EF, INVT). As designed, the static transfer switch (ASU) automatically transferred to the 120 VAC voltage regulator (EF, RG). Inverter "B" normally supplies class 1E 120 V AC power to the Engineered Safety Features (JE, ESF) and Plant Protection System (JC, PPS) and various instruments and- controls.

Class 1E power is distributed. to these systems via distribution panel 26.

Inverter "B" is backed up by 120 VAC regulated power. Immediately following the static transfer switch operation, both channels of CREFAS and CPIAS were actuated, on the BOP ESFAS system.

The root cause of the BOP ESFAS actuations is currently under investigation.

The cause of the actuations was initially believed to be a dip in the 120 VAC power due to slow static transfer switch operation. A slow transfer from the "B" inverter to the 120 VAC regulator would cause radiation monitors (IL) RU-30 (Channel "B" Control Room Ventilation Intake Monitor) and RU-38 (Channel "B" Power-Access Purge Area Monitor) to sense a loss of power and thus initiate the CREFAS and CPIAS actuations.

However, troubleshooting conducted under an authorized work document determined that the static transfer switch operated as designed. Troubleshooting also determined that the cause of the "B" inverter alarms was a loose termination on a commutating Silicon Controlled Rectifier (SCR) and an improperly set oscillator board. The improperly set oscillator board and loose termination on the commutating SCR caused two other SCRs to short and a fuse (FU) to open.

This resulted. in the "B" inverter malfunction and the subsequent transfer to CFORMthe 120 VAC regulator. A root cause of failure analysis has been initiated to determine the cause of the loose termination on the commutating SCR.

Also, during troubleshooting, RU-30 tripped intermittently when the static transfer switch transferred from the "B" inverter to the 120 VAC regulator.

The transfer to the 120 VAC regulator was successfully accomplished within 0.8 mil'liseconds as designed. As a result of these findings an investigation has been initiated to evaluate the effect of the static transfer switch operation on the radiation monitors with respect to BOP ESFAS operation. Upon the completion of this investigation a supplement to this LER will be submitted describing the root cause and corrective actions for this event.

NIIC NOA 19 81r

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NRC FossR SSSA U.S. NUCLEAR REOVLATORY COMMISSION 104)3)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OM8 NO S)50 0104

'EXPIRES: 8/3)/88 FACILITY NAME 11) DOCKET NUMSER (2)

LER NVMSER IS) PACE IS)

YEAR SSO)/ENT/AL /I1 V IS FO ss NUM IR NVMFSR Palo Verde Unit 3

'tEXT /I//R//ss sosse ie PP/ssssE s/ss eeWo'one/A/RC %%d//R 8//SA's) )IT) 0 5 0 0 0 5 3 8 7 001 0 0 0 3 QF 0 3 Since an actual emergency condition did not exist at the time of the event, there was no threat to the safe operation of the plant or the health and safety of the public. Had an emergency condition existed during the event, all safety equipment would have actuated as shown above.

There were no component, system, or safety train failures or malfunctions, other than listed above, that contributed to this event. There were no unusual work conditions that contributed to this event. There were no operator actions which contributed to this event.

4RC SORM SFSA 19 SSi

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Arizona,Nuclear Power Project P.o. BOX 52034 ~ PHOENIX. ARIZONA85072-2034 192-00195-JGH/TRB/MJC April 24, 1987.

U.S. Nuclear Regulatory Commission

'Document Control Desk washington, D.C. 20555

Subject:

Palo Verde Nuclear Generating Station. (PVNGS)

Unit 3 Docket No. STN 50-530 Licensee Event Report 87-001-00 File: 87-020-404

Dear Sirs:

Attached please find Licensee Event Report (LER) No. 87-001-00 prepared and submitted pursuant to 10 CFR 50.73. In accordance with 10 CFR 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) 932-5300 Ext. 6936.

Very truly yours,

)/6 J.

J~~

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

E. E. Van Brunt, Jr.

J. B. Martin R'. P. Zimmerman R. C. Sorensen E. A. Licitra A. C. Gehr INPO Records Center

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