ML18022A715

LER 89-007-00:on 890302,containment Leak Detection Radiation Monitor Generated High Radiation Alarm Causing Containment Ventilation Isolation (CVI) Signal & Closure of CVI Valves. Caused by Personnel Error.Personnel counseled.W/890418 Ltr

ML18022A715
Person / Time
Site:	Harris
Issue date:	04/18/1989
From:	Lew G, Richey R CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HO-890050-(O), LER-89-007-01, LER-89-7-1, NUDOCS 8904260117
Download: ML18022A715 (7)

Text

gCCP~RA,TED Dl BUTION I}EMONSTR %0.i SYFI EM REGULATOR NFORMATION DISTRIBUTION S EM (RIDS)

(DEACCESSION NBR:8904260117 DOC.DATE: 89/04/18 NOTARIZED: NO DOCKET ¹

'ACIL:50-'00 Shearon Harris Nuclear Power Plant, Unit 1, Carolina 05000400 AUTH. NAME AUTHOR AFFILIATION LEWpG.T. Carolina Power a Light Co.

RICHEYiR.B. Carolina Power a Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 89-007-00:on 890302,CVI caused by high radiation signal upon restoration of sample flow to monitor.W/890418 ltr.

W/8 ltr.

DlSTRIBUTION CODE: ZE22D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

S NOTES:Application for permit renewal filed. 05000400 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 LA 1 1 PD2-1 PD 1 1 BECKER,D 1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 ACRS WYLIE 1 1 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 DEDRO 1 1 IRM/DCTS/DAB 1 1 NRR/DEST/ADE 8H 1 1 NRR/DEST/ADS 7E 1 0 NRR/DEST/CEB 8H 1 1 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB 7 1 1 NRR/DEST/MEB 9H 1 1 NRR/DEST/MTB 9H 1 1 NRR/DEST/PSB 8D 1 1 NRR/DEST/RSB 8E -1 - .1- *- NRR/DEST/SGB- 8D 1 1 NRR/DLPQ/HFB 10 NRR/DOEA/EAB NRR ll IB 9A 1

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1 NRR/DLPQ/QAB NRR/DREP/RPB NUDOCS-ABSTRACT 10 10 1

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GMM 02 1 1 RES/DS1R/EIB 1 1 S DSR/PRAB 1 1 RGN2 FILE 01 1 1 EXTERNAL: EGSG WILLIAMSgS 4 4 FORD BLDG HOY,A 1 1 L ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYSgG 1 1 NSIC MURPHY,G.A 1 1 D

D NOZE TO ALL "RIDS" KXXPQZIS PIZASE HELP US 'Zl3 RKZQCE %ASTE! CXKZACT 'IHE DOQ3NEKZ COHISDL DESK, RXN Pl-37 (EXT. 20079) K) XXZMZHAXB VXK MME PKN DISTRIBOXXCH LISTS POR DOCUMEHZS KNJ DCRPT NEZDf TOTAL NUMBER OF COPIES REQUIRED: LTTR 44 ENCL 43

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NRC Form 300 UA. NUCLEAR REOULATOAY COMMISSION (94)3) APPROVED OMB NO. 31500104 EXPIAESI 4/31/44 LICENSEE EVENT REPORT ILER)

PAGE 3 FACILITYNAME (ll DOCKET NUMBER (2)

SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 0 5 0 0 04 00 1 OF 0 5 CONTAINMENT VENTILATION ISOLATION CAUSED BY HIGH RADIATION SIGNAL UPON RESTORATION OF SAMPLE FLOW TO THE MONITOR EVENT DATE (5) LER NUMBER (0) REPORT DATE (7) OTHER FACILITIES INVOLVED (SI SEQUENTIAL OAY YEAR FACILITYNAMES DOCKET NUMBER(0)

MONTH OAY YEAR YEAR )P4y NUMBER ER MONTH 0 5 0 0 0 1 8 8 0 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT TO THE REOUIREMENTS OF 10 CFR ('I; IChsch onc or morc of thc foiiorrfnPI (Ill OPERATINO MOOS (SI 20.402(bl 20.405(cl 60.73(c)(2) (ir) 73.71(S)

POWER 20AOS (4) (I ) (I I SOM(cl(II 60.73(cl(2) (v) 73.71(c)

LEVEL (10) 20A05(c) (I ) (El 50M(c) (2) 60.73(x )(2) (rilI OTHER ISpscify In Ahstrrct Osrow cnd In Tsxt, IVRC Form 20.405(x)(1) (ill) 50.73(c) ul(B 60.73(v)(2) (vill)(Al 3EEAI 20AOB(c) (I) (Ir) 50.73(cl(2) (II) 50.73(v)(2) (rilll(B) 20A05(cl(1)(v) 60.73(cl(2)(ill) 60.73( ~ ) (2) (x I LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER G. T. Lew, Project Engineer, Regulatory Compliance AREA CODE 2 2 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

MANUFAC. EPOATABLE MANUFAC. EPORTABLE CAUSE SYSTEM COMPONENT TO NPAOS CAUSE SYSTEM COMPONENT TUAEA NPRDS

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SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED SUBMISSION DATE (15)

YES Iifyss, compisrs EXPECTED SVEMISSIOII DATE) 'NO' ABSTRACT ILimir to f400 spscss, I.c., spproximstsiy fiftssn sinpiscpscc typcwrinsn iinni )10)

ABSTRACT:

The plant was operating in Mode 1, Power Operation at 100 percent reactor power on March 20, 1989. At 0632 hours0.00731 days <br />0.176 hours <br />0.00104 weeks <br />2.40476e-4 months <br /> (as a technician was performing routine daily checks), the Containment Leak Detection Radiation Monitor, REM-1LT-3502A-SA, generated a momentary high particulate activity radiation alarm. This alarm caused a containment ventilation isolation signal and resulted in the closure of all containment ventilation valves.

The event was initiated by a technician when an incorrect button was pushed on REM-1LT-3502A-SA. Sample flow was lost. When flow was restored, the monitor generated an invalid high radiation alarm signal.

Approximately one minute after sample flow was restored, the high radiation alarm cleared. Containment ventilation was returned to normal by 0640. Power operation of the plant was not affected by this event.

This event is reported under 10CFR50.73(a)(2)(iv) as an automatic actuation of an Engineered Safety Feature. The invalid high radiation alarm was found to result from a characteristic of the monitor's design. Corrective actions include briefing applicable personnel on the event and establishing controls such that inadvertent actuations of the purge valves do not result when reestablishing sample flow.

8'7)042601 17 890418 PDR ADOCIE, 05000400 S PNU NAC Form 300 (9 43)

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NRC fona 344A UR. NUCLEAR REOULATORY COMMISSION ISS3)

LICENSEE EVENT REPORT ILERI TEXT CONTINUATION APPROVED OMS NO. 3)50M)04 EXPIRES: SI31ISS fACILITYNAME III DOCKET NUMSER Il) LER NUMSER 14) PACE IS)

YEAR ~~4 Iim 54auENTlAL llUMSER ..'l) AEVRKIN NVM 5R SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 ~ 0 5 0 0 0 4 0 0 8 9 07 00 0 2 QF 0 5 TEXT N sere NMCP R n4MPRL PAP PRRSPAAI iVRC Anil305A 3 I II7)

DESCRIPTION:

The plant was operating in Mode 1, Power Operation, on March 20, 1989. At 0632 hou'rs, a technician was performing routine daily checks on the Containment Leak Detection Monitor, REM-1LT-3502A-SA. This monitor measures particulate and gaseous activity of the containment atmosphere. Technical Specifications require that REM-1LT-3502A-SA be operable to provide an indication of reactor coolant leakage and to provide an input to the automatic Containment Ventilation Isolation Signal (CVIS) logic. The monitor has a microprocessor based control system that interfaces with the Radiation Monitoring System (RMS) computer and actuation logics.

Channel display checks are conducted as a part of the daily tests performed on this, and similar, radiation monitors. A channel push-button on the local monitor display panel is depressed and the display checked for proper reading and lamp operability. This test can be conducted without affecting the radiation monitor's operability or outputs. While performing this test, the technician inadvertently depressed a push-button immediately below the intended channel display push-button. This action stopped sample flow to the monitor.

With the loss of flow condition, the monitor blocks outputs to high radiation alarm conditions and transmits the loss of flow status to the RMS restoring flow to the monitor removed the-block on the high radiation consoles'owever, alarm and generated the isolation signal. The act of stopping flow to the monitor caused the particulate channel to generate an invalid high radiation level alarm. A separate technician at an RMS control console located in the radiation work permit office observed the loss of sample flow alarm and immediately restored sample flow. Main Control Room operators observed the brief high radiation alarm and verified that containment ventilation isolation took place. The alarm condition cleared at 0634, within one minute after restoring flow. Ventilation was restored to normal by 0640 '

CAUSE:

Figure 1 is a summary of the causal factors related to this event. The event was initiated when the technician inadvertently depressed the "flow" push-button on the local radiation monitor control panel. Plant personnel did not kno'w that the act of restoring flow to the monitor would unblock the invalid alarm and initiate a containment ventilation isolation signals The design of the particulate channel that led to the initiation of a CVIS is discussed below.

NRC PORM 544A P U.S.OPO.'19804 024 530)455 1943)

U.S. NUCLEAR REOULATORY COMMISSION NRC Form SCCA (0431 LICENSEE EVENT REPORT ILER) TEXT CONTINUATION APPROVEO OMS NO. 3160WIOC EXPIRES: SI31 Idd FACILITYNAME (ll COCKET NUMSER (21 LER NUMSER (dl. ~ AOE (31 VCAII .'om: CCOVCNTIAL <~s ACVICION NVM II '<<NVMCCA SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 oooo o4 00 8 9 07 00 3 oF 0 5 TEXT (0'moro <<Moo << Iooodord ooo orFFINN(NIIC %%drrrr 3SEAE I I ITI CAUSE: (continued)

Investigation established that, when the sample flow is suddenly changed, a high radiation alarm is a normal but undesirable characteristic of the particulate channel. The particulate channel is an integrating channel with units of counts per minute per cubic foot. The quantity is derived by dividing the radiation detector's rate of change of count rate (counts per minute per minute) by the sample flow rate (cubic feet per minute). This calculation is accomplished by the monitor's microprocessor with instantaneous data values. When sample flow is lost, the rate of change of count rate remains constant as the flow rate decreases. The result is a rapid increase in the particulate channel output such that high radiation alarm point can easily be exceeded.

The microprocessor senses the loss of sample flow before the invalid high radiation alarm and displays a "loss of sample flow" alarm. This blocks the invalid high radiation alarm. When the sample pump is restarted, the loss of sample flow alarm is removed and the existing invalid high radiation alarm is displayed and processed by the system logic. The alarm condition will clear in about one minute after sufficient sample flow is integrated.

ANALYSIS'his event is reported as an actuation of an Engineered Safety Feature in accordance with 10CFR50.73(a)(2)(iv). There were no safety consequences as a result of this event. The Containment Building ventilation system was isolated ag required by system design. The Containment Leak Detection System is required to be operable in Plant Modes 1 through 4. The actuation of this signal does not have any immediate impact on other plant systems in any mode.

This behavior of the particulate channel was also the probable cause of the events described in LER 87"067"00. This event occurred on December 14, 1987, as a chemistry technician was drawing a grab sample from the monitor. LER 87-067 stated that a "spurious electronic signal spike" was the cause of the event. A sharp reduction in sample flow probably occurred in the LER 87-067-00 event. The LER 89-07 event demonstrates that a reduction in sample flow can cause an invalid high radiation alarm.

NIIC FOIIM SCCA r oU.S.OPO.'I dddO 024 53(VCdd (0431

NRC Sons 3$ 8A US. NUCLEAR REOULATORY COMMISSION IB83I LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMB NO. 3150W104 EXPIRES: 8/31/8$

SACILITY NAME III DOCKET NUMBER IEI LER NUMBER (dl PACE (3l

?N OEOVENTIAL ACVIOION YEAR nvM EA nvM os SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 0 5 0 0 0 4 0 0 0 7 0 0 0 4 QF 0 TEXT /8'or>> Opec>> /I Io>>o/mcd voo A/8/oso/HID Pcs?II ~3/ Iltl CORRECTIVE ACTION:

The following actions are being taken to prevent recurrence of the event:

1. The individual that made the error was counselled to exercise more care in operating the radiation monitor.

,2. Appropriate plant personnel will be provided with the findings of this event and instructed on the interdependence of sample flow rate and calculated radiation levels

3. A precaution statement will be added to the appropriate plant procedures to serve as a reminder that loss of sample flow can create a false high radiation alarm.

4. Plant procedures will be modified to specify the action required upon a loss of sample flow.

ENERGY INDUSTRY IDENTIFICATION SYSTEM (EIIS) CODES:

Com onent or S stem EIIS Code Containment Isolation Valves VA Containment Leak Detection System BD Containment Structure NH Containment Ventilation VA Radiation Monitor IL Radiation Monitoring System IL NRC SCAM 3oos AU.S.OPO;I BSBWBEO $ 38/4dd I883)

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VENTILATION SAMPLE CHANNEL LOGIC CHANfIEL OUTPUT SAMPLE FLOW CHAf)f(EL HIGH ISOLATION FLOV LOST WHEN BLOCKS OUTPUT RESULTS If)

RESTORED ALARM SIGNAL INITIATED INCORRECT BUTTON ON LOSS OF ALARM ON MANUALLY UNBLOCKED BY rr PUSHED SAMPLE FLOW DECREASING FLOV HIGH ALARM E

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HARRIS NUCLEAR PROJECT P.O. Box 165 New Hill, NC 27562 File Number'SHF/10-13510C Letter Number. HO-890050 (0)

U.S. Nuclear Regulatory Commission ATTN: NRC Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 DOCKET NO. 50-400 LICENSE NO. NPF-63 LICENSEE EVENT REPORT 89-007-00 Gentlemen.'n accordance with Title 10 to the Code of Federal Regulations, the enclosed Licensee Event Report is submitted. This report fulfills the requirement for a written report within thirty (30) days of a reportable otcurrence and is in'- accordance" with the format set forth in NUREG-1022, September 1983.

Very truly yours, R. B. Richey, Man ger Harris Nuclear Project RBR:acm Enclosure cc'Mr. R. A. Becker (NRR)

Mr. W., H. Bradford (NRC SHNPP)

Mr. S. D. Ebneter (NRC - RII) l MEM/LER-89-007/1/Osl g