ML17329A448

LER 92-003-00:on 920307,sampled But Unmonitored Liquid Release Occurred W/Loss of 120-volt Ac Power to Liquid Effluent Release Radiation Monitor.Caused by Failed Trip/ Isolation Relay.Design Change initiated.W/920406 Ltr

ML17329A448
Person / Time
Site:	Cook
Issue date:	04/06/1992
From:	Blind A, Weber G INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-92-003-01, LER-92-3-1, NUDOCS 9204140325
Download: ML17329A448 (8)

Text

ACCELERATED DIS UTION DEMONSTR TION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9204140325 DOC.DATE: 92/04/06 NOTARIZED: NO DOCKET FACIL:50-315 Donald C. Cook Nuclear Power Plant, Unit 1, Indiana M 05000315 AUTH. NAME AUTHOR AFFILIATION

.WEBER,G.A. Indiana Michigan Power Co. (formerly Indiana 6 Michigan Ele BLIND,A.A. Indiana Michigan Power Co. (formerly Indiana 6 Michigan Ele.

RECIP.NAME RECIPIENT AFFILIATION R

SUBJECT:

LER 92-003-00:on 920307,sampled but unmonitored liquid release occurred w/loss of 120-volt ac power to liquid D effluent release radiation monitor. Caused 'by failed trip/

isolation relay. Design change initiated.W/920406 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

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

NOTES: A, RECIPIENT COPIES RECIPIENT COPIES D ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD3-1 LA 1 1 PD3-1 PD 1 1 D STANG,J 1 1 INTERNAL: ACNW 2 AEOD/DOA 1 AEOD/DSP/TPAB 1 AEOD/ROAB/DS P 2 NRR/DET/EMEB 7E 1 NRR/DLPQ/LHFB10 1 NRR/DLPQ/LPEB10 1 NRR/DOEA/OEAB 1 NRR/DREP/PRPB11 2 NRR/DST/SELB SD 1 NRR/DST/SICB8H3 1 NRR/J3SXJ PLEBS D1

. NRR/DST/SRXB 8E 1 EG'ILE 1 RES/DSIR/EIB 1 -":"-RGN3 'F'1O'E" 01 1 EXTERNAL: EG&G BRYCE,J.H 3 L ST LOBBY WARD 1 1 NRC PDR 1 NSIC MURPHY' A ~ 1 1 NSIC POORE,W. 1 NUDOCS FULL TXT 1 1 D

A D

D NOTE TO ALL "RIDS" RECIPIENTS:

S PLEASE HELP US TO REDUCE K'i XSTE! CONTACT THE DOCUMENT CONTROL DESK, ROOi~I PI-37 (EXT. 20079) TO LLlb IINATE YOUR NAME FROiv1 DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 30 ENCL '0

indiana Michigan power Company "cok Nuc!ear P!ant One Cook Place

-.'.ogman. V) -'~':i6 F16 ~os o001 t~

Slia WDIANA iWCHlOAN POWER April 6, 1992 United States Nuclear Regulatory Commission Document Control Desk Rockville, Maryland 20852 Operating Licenses DPR-58 Docket No. 50-315 Document Control Manager:

In accordance with the criteria established by 10 CFR 50.59 entitled Licensee Event Re ort S stem the following report is being submitted:

92-003-00 Sincerely, A, A. Blind Plant Manager

/sb Attachment Co D. H. Williams, Jr.

A. B. Davis, Region E. E. Fitzpatrick III P. A. Barrett B. F. Henderson R. F. Kroeger B. Walters - Ft. Wayne NRC Resident Inspector T. Colburn - NRC J. G. Keppler M. R. Padgett G. Charnoff, Esq.

D. Hahn INPO S. J. Brewer/B. P. Lauzau B. A. Svensson AF'Rg 0]gag I ~

NRC FORM 366 U.S. NUCLEAR REGVLATORY COMMISSION (669) APPROVED OMB NO. 31504)104 5 XP IR E S: 4/30/02 ESTIMATED BURDEN PER RESPONSE TD COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 50JI HRS. FORWARD LICENSEE EVENT REPORT (LER) COMMENTS REGARDING BURDEN FSTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (PS)30). U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104), Off(CE OF MANAGEMENTAND BUDGET, WASHINGTON, OC 20503.

'ACILITY NAME (I) DOCKET NVMBER 12)

DONALD C. COOK NUCLEAR PLANT UNIT 1 0 5 0 0 0 3 1 5 1 OFO 5

IQUID RELEASE TO UNRESTRICTED AREA IN VIOLATION OF TECHNICAL SPECIFICATION 3/4.3.3 DUE TO FAILURE OF RADIATION MONITOR RRS-1000 EVKNT DATE (5) LER NUMBER (Sl REPORT DATE LT) OTHER FACILITIES INVOLVED FSI MONTH OAY YEAR YEAR HBS SEDVENTtIL nEvtsloN MONTH OAY YKAR PACii.tTY NAMES DOCKF 7 NUMBERISI Cigar~ NUMBE R NUMBER D.C. COOK PLANT UNIT 2 0 5 0 0 0 3 1 6 03 07 9 2 9 2 0 0 0 0 04 069 2 0 S 0 0 0 OPERATING THIS REPORT IS SUBMITTED PURSUANT T0 THE RLOUIRKMENTS OF 10 CFR ('I: /Cneco One or more o/ Cne /ottowinP/ (11 MODE (Sl 20A02 Ib) 73.71(6) 20.405(cl 50.73(eI(2)iirl POWE R 20AOS lsl(1)(i) SODS(c) I)I 50.73(s I (21(el '3.7((c)

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NAME TELKPHONE ttUMB'KR AREA CODE G. A. WEBER PLANT ENGINEERING DEPARTMENT SUPERINTENDENT 61 646 5- 5901 COMPLETE ONE LINK FOR EACH COMPONENT FAILURE DESCRI ~ ED IN THIS REPORT (13)

CAUSE SYS'EM COMPONENT MANUFAC- COMPONEN'7 MANVFAC f.PORTABL TURER TQ NPRDS '~S($ ~(c~c CAUSE SYSTEM TVRER TO NPRDS

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SVPPLEMENTAL REPORT EXPECTED (14) MONTH OAY YEAR EXPECTED SUBMISSION DATE iISI YES II/ rsL compt<<e EXP'ECTED SVBSIISSION DATE/ X No ABSTRACT ILrmrt to ts00 rosser I e., eoororrmeretrr trtreen trnprs roose troerwrtrrn Ann/ (161 On March 7, 1992 at approximately 1533 hours0.0177 days <br />0.426 hours <br />0.00253 weeks <br />5.833065e-4 months <br />, a sampled but unmonitored liquid release occurred with the loss of 120 VAC power to the Liquid Effluent Release Radiation Monitor, RRS-1000. The DC battery backup power supply -was determined to have failed prior to the event. Loss of all power to the monitor should have resulted in an automatic termination of thi.s release. However, the release had to bemanually terminated at approximately 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> when the Operator discovered the monitor to be de-energized. Continuation of the release with the monitor inoperable was a violation of Technical Specification 3.3.3.9. Based on a sample of the monitor tank contents taken prior to the release and tank discharge and dilution flow rates, the actual concentration of the release to'Lake Michigan was 4.S1E-3 of the 'Maximum Permissible Concentration (MPC). Therefore, 10CFR20 limits were not,challenged.

The principal cause of this event was the failure of the monitor to close the Liquid Waste Release Discharge Isolation Valve, 12-RRV-285, and to trip the running Monitor Tank Pump when the radiation monitor lost AC power. This failure was traced to a failed trip/isolation relay'n the monitor. The alarm relay module, battery, battery charging module, and circuit breaker. were replaced. A design change was initiated to reduce the load and to improve the transient energy protection on the trip/isolation relay. An was revised to perform an AC power check prior to a release and a Operations'rocedure monitor check immediately after release initiation. Compensatory double sampling will be conducted until an Operational Readiness Review of the monitor is completed.

NRC Form 366 (64)9)

NRC FORM 366A US. NUCLEAR REGULATORY COMMISSION (6491 LICENSEE EVENT O REPORT (LER)

APPROVED OMB NO. 3160410l EXPIRES: l/30/92 ESTIMATED BURDEN PER RESPONSE TO. COMPLY WTH THIS INFORMATION COLLECTION REOUESTI 600 HRS. FORWARD TEXT CONTINUATION COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH IP4301. U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20656, AND TO THE PAPERWORK REDUCTION PAO/ECT (3150410l1. OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, OC 20503.

FACILITY NAME 111 DOCKET NUMBER Ill LER NUMBER 14) PAGE IS)

VEAA SEQUENTIAL IIEVISION NUMelrl NUMBSII DONALD C. COOK NUCLEAR PLANT" UNIT 0 5 0 0 0 0 1 3 g 5 9 2 0 3 0 0 0 2 OF 0 5 TEXT ///more epochs re cere'rerr, Iree edca6orN/H/IC %%dmr SBSAB/ (ITI Co d tio s P o to Occurrence:

Unit 1 in Mode 1 (Power Operation), at 99 percent power.

Unit 2 in Mode 5 Descr t o of Event:

On March 7, 1992, actions were initi.ated to release liquid waste from Radwaste Li.quid Effluent Monitor Tank P3 (Release number L92-020). Prior to beginning the release, the Monitor Tank was sampled by Chemistry personnel in accordance with 12 THP 6020 LAB.037. Operations personnel verified that RRS-1001" was operable in accordance with procedure ++12 OHP 4021.006.004.

Following preparations to set up for the release through Monitoi Tank No. 3, the operator pressed the Alarm Acknowledge button on the front of RRS-1000, located in the Auxiliary Buildi.ng, to enable the start of the release.

alarm acknowledgement clears the trip functions to allow openi.ng of the The Liqui.d Waste -Release Discharge Isolation Valve (EIIS/ISV-WD) (12-RRV-285) so that flow can be initiated. After verifying that all alarms were clear at the monitor, the WDS Operator proceeded to the WDS Panel, a short distance away from the monitor but out of sight of the monitor, to open 12-RRV-285.

valve was opened and the, release began at 1533 hours0.0177 days <br />0.426 hours <br />0.00253 weeks <br />5.833065e-4 months <br /> (Control Room LogThe entry).

The release continued until approximately 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br />. At 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br />, the Waste Disposal System (WDS) Operator returned to the monitor, observed that appeared to be de-energized, and promptly called the Control Room to request a it channel check of the RRS-1001, Radioactive Liquid Disposal Effluent Header Sample Gamma Radiation Detector (EIIS/IL-MON). At this time, discovered that RRS-1000, Radioactive Liquid Detector Data Acquisition Module it was had been in a transmit timeout status since 1531 hours0.0177 days <br />0.425 hours <br />0.00253 weeks <br />5.825455e-4 months <br />, i.ndicating that the Radiation Monitoring System Control Terminal in the Control Room had lost communication with the monitor. This failure -of RRS-1000 should have tripped 12-RRV-285 and any running monitor'tank pumps to terminate the release automatically. This did not occur. The release was immediately termi.nated through operator action.

Technical Specification 3/4.3.3 LCO 3.3.3.9 requires that with a required channel inoperable, releases may continue up to thirty days providing at least two independent samples are analyzed in accordance with Technical Specification 4.11.1.1.1 and at .least two qualified individuals verify discharge valving prior to initiating the release, otherwise, suspend releases via this pathway. This specification was not fulfilled from approximately 1533 to 1600 hours0.0185 days <br />0.444 hours <br />0.00265 weeks <br />6.088e-4 months <br /> for release L92-020.

Cause of Event:

Investigation of this event determined that the root cause of the monitor's inability to isolate the liquid release upon loss of power was the failure of the monitor's trip/isolation relay, AK-3. Upon loss of power to the monitor, the relay is de-energized and the relay's contacts should have opened. This, in turn, should have resulted in tripping the Monitor Tank Pump and isolation N AC Form 366A I6691

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (649) APPROVED 0MB NO, 31504(0E EXPIRESI 4130/92 LICENSEE EVENT REPORT (LER) ESTIMATFD BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COL(.ECTION REQUEST( 500 HRS. FORWARD TEXT CONTINUATION COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS ANO REPORTS MANAGEMENT BRANCH (P430I, U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON. OC 206S5, AND TO 1HE PAPERWORK REDUCTION PROJECT (31500(OE), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON,OC 20503.

FACILITY NAME (ll DOCKET NUMBER 12)

LER NUMBER (6) ~ AGE (3)

Y EAR ~i@ SEQUENTIAL'<Pg NUMOER REV IS ION NUM ER DONALD C. COOK NUCLEAR PLANT UNIT TEXT (Jl more Eoeco 1 o 5 o o o 3 15 9 2 0 0 30 0 0 3 OF 0 5 Je reeuia6 oee aJI((encl HRC %%drm 3EE(AS I (12) d2 of 12-RRV-285. Two factors contributing to this event weres 1) The failure of the backup power source. A backup power source should have allowed the monitor to continue normal operation, including trip functions and monitoring of the releaseg and 2) The monitor's alarm logic. Alarms signaling the failure or abnormal status of the mo'nitor are short in duration (approximately 7 seconds) and do not require operator acknowledgement. Without the ability to audibly discriminate the transmit timeout (failed monitor) condition from the hi/low flow alarms that occur while setting up release, the operator did not recognize the alarm as indicative of a failed monitor. This increased the duration of the release. Had the operator checked the alarm log printout, the failed status could have been confirmed.

Inspection of the back-up battery revealed that the electrolyte had almost, completely evaporated. The battery had recently been added to the Plant's Preventive Maintenance Program, but had not yet come due for service. The back-up battery is not required for proper operation of the monitor, but is only intended to preserve normal functions of the monitor the monitor is interrupted.

if the AC power to The AC power supply is provided'rom a battery backed critical instrument bus..

The power supply switch,- which includes an integral overload trip feature, was found in the OFF position. No evidence of an overload condition was found.

Failure .of all power in the monitor eliminates all means to maintain the alarm relays energized. The normally open contacts that supply 120 VAC to the auxiliary relays, R18-AUX and R18-AUX1 (EIIS/IL-RLY)r should have de-energized, closing the isolation valve 12-RRV-285, tripping the running Monitor Tank Pumps, and providing an alarm on the local WDS panel.

The relay was removed from the monitor. The contacts were found.to be in the open position, however, the contact surfaces were pitted and discolored indicating evidence of thermal stress. Localized heating effects are believed to have caused the relay contacts to have fused together. The contact surfaces were apparently broken free from one another as a result of cycling the relay during the troubleshooting evolution.

The AK-3 relay coil is powered from a 12 VDC internal power supply, which in turn, is normally powered from the 120 AC source via a rectifier/filter circuit, or upon loss of AC, the back-up battery. The coil is energized when all the logic inputs to the Alarm Module are high. Any alarm condition will cause logic inputs to go low, which causes an inverter to go high, de-energizing the alarm relay coil. Loss of the +12 VDC source will also de<<energize the alarm relay.

Review, of vendor literature determined that the AK-3 relay contacts arerated for 2 amps, 115 VAC, and are made of palladium in a cross-bar arrangement. In this application, they close ro energize auxiliary relays R18-AUX and NRC Form 366A l649)

NRC FOAM 366A U.S. NUCLEAR REGULATORY COMMISSION 154)S) APPROVED OMB NO. 31500104 EXP/R'ESI 4/30/93 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT (LER) INFORMATION COLLECTION REOUEST: 50A) HAS, FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE. RECORDS TEXT CONTINUATION ANO REPORTS MANAGEMENT BRANCH (P4)30), U.S. NUCLEAR AEGULATORY COMMISSION. WASHINGTON. OC 30555, AND TO 1ME PAPERWORK REDUCTION PROJECT (3)504)1041. OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, DC 30603.

FACILITY NAME II) DOCKET NUMBER tl) I.ER NUMBER ISI PAGE 13)

YEAR io4 660VENTIAL NVMBEII

'P

@ REVISION IIUMICR DONALD C. COOK NUCLEAR PLANT UNIT 1 o s o o o 3 1 5 9 2 0 0 3 0 0 0 <OF 05 TEXT /IImar <<ocoir /oqwaf, ooo aeWabnV HRC Ann 36643/ I)71 Ca s v ue R18-AUX1 (EIIS/IL-RLY). The energy required to energize and de-energize these auxiliary relays, coupled with rapid cyclic alarm states which occur while setting up sample flows, degraded and damaged the normally open contacts of AK-3. The AK-3 relay contacts were intended to switch low power signals. The auxiliary relays normally draw approximately 0.3 amps operating current at 115 VAC, however, transient energies may be an order of magnitude greater.

Inspection of the contacts revealed evidence of damage induced by making and breaking against the auxiliary relay loads.

Anal sis of Event:

Based on the recorded Monitor Tank release flow rate (1.07E+2 gpm}, the dilution water flow rate (8.30E+5 gpm), and the radioanalytic results of the Monitor Tank being released (3.50 MPC), the actual total MPC value for the release was 4.51E-3 MPC. Consequently, this event did not have an impact on the health and safety of the public.

Corrective Action:

A Radiation Protection Technician found the breaker located inside the monitor tripped. The technician reset the breaker and re-initialized RRS-1000 on March 7, 1992 at, 1625 hours0.0188 days <br />0.451 hours <br />0.00269 weeks <br />6.183125e-4 months <br />. The Plant Manager directed that compensatory double sampling be initiated. Double samples were taken and the release of the No. 3 monitor tank was reinitiated under Release number L92-021, in accordance with the provision of Technical Specifications.

The backup battery and associated charging module were found deficient and were'replaced. All other Technical Specification Radiation Monitor batteries were verified to be within the Preventive Maintenance Program and had been serviced at least once. The required preventive maintenance activities for Unit 1 and Unit 2's Technical Specification Radiation Monitor batteries will be performed during the 1992 outages, prior to unit startup.

The circuit breaker was also replaced. The Operations'rocedure for liquid releases through RRS-1000 was revised to ensure that AC power is present prior to a release and to perform a monitor check, which would identify a loss of AC power, immediately after release initiation.

The alarm relay module was replaced.

A Design Change Proposal (MM-309) was written to split the AK-3 contact current load with a set of spare, normally open contacts on the relay, changing out the transient suppression device which is installed across the

'auxiliary relay coil and rewiring the auxiliary relays. The transient suppression device consists of a metal oxide varistor. The rating of the replacement varistor will be selected to improve the protection provided to, AK-3 over that provided by the currently installed varistor. The relay wiring NRC Form 366A I6691

NRC,FORM 368A UA. NUCLEAR REGULATORY COMMISSION (6 JI9 I APPROVEO OMS NO. 31600104 EXPIRES: e(30/92 LICENSEE EVENT REPORT (LER) ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST( 640 HRS. FORWARD TEXT CONTINUATION COMMENTS REGARDING SURDEN ESTIMATE TO THE RKCORDS AND REPORTS MANAGEMKNTSRANCH (F430(, U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20666, AND TO 1ME PAPERWORK REDUCTION PROJECT (3(600((M). OFFICE OF MANAGEMFNTAND BUDGET, WASHINGTON, DC 20603.

FACILITY NAME (II DOCKET NUMSER (2( LER NUMSER LSI PAGE Ill YEAR 564USNTIAL RSYCSION rrUMeen rr UM 6 II DONALD C.'OOK NUCLEAR PLANT UNIT 1 o 5 0 0 o 3 1 9 2 0 0 3 00 0 OF 0 5 TKXT N mare opece le rFrr'rerS aoe aASUOnee( ArlIC %%dnn RSSESJ (171 scheme will be revised to use one of the auxiliary to energize the other auxiliary relay. This will further reduce therelays load on the AK-3 relay contacts. This Design Change will be installed by April 10, 1992.

Compensatory double sampling will be conducted until an Operational Readiness Review of the monitor is completed.

A commitment remains open at this time for a previous Licensee Event Report

'(LER 50-315/91<<010), concerning the audible alarm issue. The commitment will be resolved under that LER.

0 I Liquid Waste Discharge Monitor Plant Designations RRS-1000 Manufacturer3 Eberline Installed Design: American Electric Power Service Corporation (AEPSC)

U I LER 50-315/91-003 LER 50-315/91-010 NRC Form 366A (689)