ML17303A473

From kanterella
Jump to navigation Jump to search
LER 87-009-00:on 870604,inadvertent Control Room Essential Filtration Actuation Occurred Due to Radiation Monitor Pump Cycling.Caused by Motor Drawing Too Much Current.Ground to Motor & Radiation Monitor separated.W/870702 Ltr
ML17303A473
Person / Time
Site: Palo Verde Arizona Public Service icon.png
Issue date: 07/02/1987
From: Bradish T, Haynes J
ARIZONA PUBLIC SERVICE CO. (FORMERLY ARIZONA NUCLEAR
To:
NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
192-00233-JGH-T, 192-233-JGH-T, LER-87-009-01, LER-87-9-1, NUDOCS 8707140055
Download: ML17303A473 (10)


Text

cf REGULA /'NFORMATION DISTR IBUTI STEM (R IDS)

I ACCESSION NBR: 8707140055 DOC. DATE: 87/07/02 NOTARIZED: NO DOCKET FACIL: STN-50-528 Palo Verde Nuclear Stations Unit ii Arizona Publi 05000528 AUTH. NAME AUTHOR AFFILIATION BRAD I SH'r T. R. Arizona Nuclear Power Prospect (formerly Arizona Public Serv HAYNES> J. G. Arizona Nuclear Power Prospect (formerly Arizona Public Serv RECIP. NAME RECIPIENT AFFILIATION

SUBJECT:

LER 87-009-00: on 870604i inadvertent control room essential filtration actuation occurred due to radiation monitor pump cycling. Caused bg motor draeing too much current. Ground to motor 5 radiation monitor separated. W/870702 itr.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR I ENCL SIZE:

TITLE: 50. 73 Licensee Event Report (LER) i Incident Rpti etc.

NOTES: Standardized plant. M. Davis'RR: 1Cg. 05000528 REC IP IENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD5 LA 1 1 PD5 PD 1 1 LICITRAiE 1 1 DAVISi M 1 1 INTERNAL: ACRS M ICHELSON ACRS MOELLER AEOD/DOA 1 1 AEOD/DSP/ROAB AEOD/DSP/TP*B 1 DEDRO 1 1 NRR/DEST/ADE 1 0 NRR/DEST/ADS 1 0 NRR/DEST/CEB 1 NRR/DEST/ELB 1 1

.NRR/DEST/ICSB 1 NRR/DEST/MEB 1 NRR/DEST/MTB 1 1 NRR/DEBT/PSB 1 NRR/DEST/RSB 1 1 NRR/DEST/SGB 1 1 NRR/DLPG/HFB 1 1 NRR/DLPG/GAB 1 1 NRR/DOEA/EAB 1 NRR/DREP/RAB 1 NRR/DREP/RPB 2 N PMAS/ILRB NRR/PMAS/PTSB 1 1 EG F I 02 1 1 RES DEP Y G I 1 1 RES TELFORDi J 1 1 RES/DE/EIB 1 1 RGNS F I LE 01 1 1 EXTERNAL: EGKG GROHi M 5 5 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRIS' 1 1 NSIC MAYST G 1 1 NOTES:

TOTAI NUMBER OF COPIES REQUIRED: LTTR 46 ENCL 44

f 1

NRC Form 345 4 US. NUCLEAR REOULATORY COMMISSION 194)3l APPROVED OMB NO. 31600104 LICENSEE EVENT REPORT (LER) EXPIRESI.5/31/SS FACILITY NAME (II DOCKE'7 NUMBER (2) PA E I Palo Verde Unit 1 o 5 o o o52 1 oF 3 Inadvertent Control Room Essential Filtration Actuation Due to Radiation Monitor Pum C clin EVENT DATE IS) LER NUMBER (SI AEPORT DATE (7) OTHER FACILITIES INVOLVED (SI MONTH DAY YEAR YEAR SEOVENVIAL REVOXW MONTH OAY YEAR FACILITYNAMES DOCKET NUMBER(3) e>M NVMSER PL> NUMBER N A 0 5 0 0 0 0 6 0 8 7 0 0 9 00 070 287 N/A 0 0 5below 0 0 OPERATINQ THIS REPORT IS SUBMITTED PURSUANT TO THE AEOUIREMENTS OF 10 CFR (II (Chere one or more ol the followinpl (11)

MODE ISI 20A02(ol 20.405(c I 50,73( ~ )(2)(iv) 73.710II POWER 20AOS( ~ l(1) (I) 50.34(c)(ll 50.734) (2 I 4) 73.71(cl LFVEL (10) p p 20.405( ~ llll(4) 50.34(cH2) 50.73(o)(21(r4) OTHE R /Spec/re in A ho trect end in Feet. /Vd C Form 20.405(o)11)(45 50.73( ~ )(2)(0 50.734) (2) (ri4) (A) 3SSAI 20AOS( ~ )(1)IIv) 50.734) (2) I 4) 50.734)(2) lrIB)(S) 20AOS( ~ l(1)(v) 50.734)(2) (I BI 50.734l(2) (c)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER AREA CODE T. R. Bradish, Compliance Supervisor (Ext. 6936) 0 2 2 300 COMPLETE ONE LINE FOR EACH COMPONENT FAILVAE DESCRIBED IN THIS REPORT (13)

MANUFAC. EPORTABLE i?~

CAUSE SYSTEM COMPONENT MANUFAC. EPORTABL TURER TO NPRDS TVRER TO NPRDS ',

tkgPg~$ $ ?? ~

j~j8j:N@P),@@gg S>@vs-;P>'.jbg%$ .

Kp 20 Y

~<y@Njj~N~~

X I L P X99 N SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED SUBMISSION DATE (15)

YES Ill yet, corno/ere EXPECFED SUBMISSION DATE/ NO AssTRAcT ILimit to todd toeceL ie., epproelmetery A/teen tinp4 tpece trpewritten i>nod (15)

At 0527 on June 4, 1987 Palo Verde Unit 1 was in Mode 1 (Power Operation) at 100 percent power when the Control Room Air Intake Radiation Monitor (RU-30) generated a high radiation signal and actuated the Control Room Essential Filtration System. The actuation occurred on the "B" Train and crosstripped the "A" Train as designed. All associated equipment operated properly.

Investigation of the actuation revealed that the sample pump motor was cycling off and on. Troubleshooting identified that the motor was drawing too much current causing the thermal overloads to actuate. After the thermal overloads cooled, the motor would automatically restart. As the motor cycled, the radiation monitor would generate a spurious high radiation signal. The root cause of the motor drawing too much current has been identified to be a malfunctioning air sample pump.

The motor and the radiation monitor utilize the same ground. Cycling of the motor causes electrical noise to pass from the common ground to the radiation monitor which generates a spurious high radiation signal.

As corrective action to prevent recurrence the ground to the motor and radiation monitor will be separated and the air pump will be replaced.

Although Control Room Essential Filtration actuations have occurred previously due to radiation monitor spikes, no events have been reported where the cycling of the sample pump motor caused an actuation; 8707140055 870702 NAC Form 344 PDR ADOCK 05000528 PDR

~t I

J 1

p E

II

NRC Form 344A US, NUCLEAR REOULATORY COMMISSION (943 l LICENSEE EVENT REPORT ILER) TEXT CONTINUATION APPROVEO OM8 NO 3150&104 EXPIRES( 4(31/88 FACILITY NAME (1( DOCKET NUM4ER (3(

LER NUMSER (4( ~ AOE (SI aoE sEQvENTIAL ':Prr

@or osvrsloN NVM 4 4 IIVM SR Palo Verde Unit 1 o s o o o 52 887 009 0 02 oF 0 TEXT lllmort Iotct (I otrrltrE tot ortooro(HRC Forrrr 3(EL(4l ((T)

At 0527 on June 4, 1987 Palo Verde Unit 1 was in Mode 1 (Power Operation) at 100 percent power when the Control Room Air Intake Radiation Monitor (RU-30) (IL)

(RI) generated a high radiation signal and actuated the Control Room Essential Filtration System (VI) . This was identified by control room annunciation (ANN).

The actuation accurred on the "B" train and crosstripped the "A" train as designed. All associated essential ~quipment operated properly. RU-30 was reset at 0554 on June 4, 1987. The event lasted approximately 27 minutes.

Equipment failure and low sample flow alarms were received for RU-30 in the control room at approximately the same time as the Engineered Safety Features actuation. 'ased on this information the Control Room Operators (utility-licensed) declared RU-30 inoperable. Grab samples taken after the event revealed no abnormal radiation levels.

Due to the inoperability of the other Control Room Air Intake Radiation Monitor (RU-29) the Control Room Essential Filtration System was placed in the recirculation mode as required by Technical Specification ACTION requirements.

RU-29 had been declared inoperable to perform routine preventive maintenance.

Investigation of the actuation revealed that the sample pump (P) motor (MO) was cycling off and on. Troubleshooting identified that the motor was drawing too much current causing the thermal overloads to actuate. After the thermal overloads cooled, the motor would automatically restart. As the motor cycled the radiation monitor would generate a spurious high radiation signal. The root cause of the motor drawing excessive current has been attributed to a malfunctioning air sample pump. The pump is a Roots Pump (Model 8AF22). An analysis will be performed on the sample pump to determine the root cause of the malfunction.

The motor and the radiation monitor utilize the same ground. When the motor cycles, electrical noise passes from the common ground to the radiation monitor causing the monitor to generate a spurious high radiation signal. The monitor is a Kaman Monitor (Model f/952105-002).

As corrective action to prevent recurrence the ground to the motor and radiation monitor-will be separated for RU-29 and 30 in Unit 1. The effects of the grounding changes will be monitored to determine if the ele'ctrical noise has been reduced. An evaluation will then be conducted to determine if the modifications should be incorporated in Units 2 .and 3., The air sample pump will also be replaced.

The Control Room Essential Filtration System actuated as designed for a high radiation signal and all required equipment operated properly. Based on samples taken after the event, no abnormal radiation levels existed therefore, this event had no impact on the health and safety of the public.

NIIC IORM Soot (9 STI

fl g

NRC Form 355A I9 83 I FACILITY NAME III t

LICENSEE EVENT REPORT ILER) TEXT CONTINUATION DOCKET NUMSER (1I l LER NUMSER ISI U.S. NUCLEAR FIEOULATO/IYCOMM/SSION APPROVED OM8 NO 3ISOWIOO EXPIRfS: 8/31/88

~ AOE U/I YEAR 5 E O V5 8 5 I*I P~jo IIEYISIorr P o NVM ER NVM EA Palo Verde Unit 1 o s o o o 52 887 '009 0 0 03 oFO 3 TEXT ////ooro I/roco /5 For/rrorE I/oo /r///torso/HRC Forrrr 3OSAO/ lltl Although Control Room Essential Filtration actuations have occurred previously due to radiation monitor spikes, no events have been reported where the cycling of the sample pump motor caused an actuation.

Should other concerns or information pertinent to this event be discovered, a supplement to this report will be issued.

There were no structures, systems, or components other than RU-29 that were inoperable at the start of the event that contributed to the event. There were no other manually or automatically initiated safety system responses.

4RC IORM 355k I9 53<

Arizona Nuclear Power Project P.O. SOX 52034 ~ PHOENIX, ARIZONA85072-2034 192-00233-JGH/TRB/JHT July 2, 1987 Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Palo Verde Nuclear Generating Station (PVNGS)

Unit 1 Docket No. 50-528 Licensee Event Report 87-009-00 File: 87-020-404

Dear Sirs:

Attached please find Licensee Event Report (LER) No. 87-009-00 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) 932-5300, Ext. 6936.

Very truly yours, I-1~~~

J. G. Haynes Vice President Nuclear Production JGH/JHT/cld Attachment Cce O. M. DeMichele (all w/a)

E. E. Van Brunt, Jr.

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

(

li I

I I

t l

1