ML17221A660

LER 88-001-00:on 880205,HPSI Pump C Started Due to Spurious Trip & Immediate Reset of Breaker.Caused by Personnel Error. Breaker Replaced.Equipment to Be Evaluated by Vendor.W/ 880307 Ltr

ML17221A660
Person / Time
Site:	Saint Lucie
Issue date:	03/07/1988
From:	Connor J, Conway W FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
L-88-110, LER-88-001-03, LER-88-1-3, NUDOCS 8803110151
Download: ML17221A660 (5)

Text

kC CELE RATED DISIOBUTION DE MON STRION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:8803110%51 DOC.DATE: 88/03/07 NOTARIZED- NO DOCKET FACIL:50-335 St. Lucie Plant, Unit 1, Florida Power & Light Co. 05000335 AUTH. NAME AUTHOR AFFILIATION CONNOR,J.W. Florida Power & Light Co.

CONWAY,W.F. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 88-001-03:on 880205,inadvertent start of high pressure safety injection pump 1C occurred.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR I ENCL TITLE: 50.73 Licensee Event Report (LER), Incident Rpt, etc.

Z SIZE:

NOTES RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 TOURIGNY,E 1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 AEOD/DOA 1 1 AEOD/DSP/NAS 1 1 AEOD/DSP/ROAB 2 2 AEOD/DSP/TPAB 1 1 ARM/DCTS/DAB 1 1 DEDRO 1 1 NRR/DEST/ADS7E4 1 0 NRR/DEST/CEB8H7 1 . 1 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB7A 1 1 NRR/DEST/MEB9H3 1 1 NRR/DEST/MTB 9H 1 1 NRR/DEST/PSB8D1 1 1 NRR/DEST/RSB 8E 1 1 NRR/DEST/SGB 8D 1 1 NRR/DLPQ/HFB10D 1 1 NRR/DLPQ/QAB10A 1 1 NRR/DOEA/EAB11E 1 1 NRR/DREP/RAB10A 1 1 NRR/DREP/RPB10A 2 2 QDRTS= SIB9A1 1 1 NRR/PMAS/ILRB12 1 1 G 02 1 1 RES TELFORD,J 1 1 RES DE/EIB 1 1 RES/DRPS DIR 1 1 RGN2 FILE Ol 1 1 EXTERNAL: EG&G GROH,M 5 5 FORD BLDG HOY P A 1 1 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRIS,J 1 1 NSIC MAYS,G 1 1 I

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A D

TOTAL NUMBER OF COPIES REQUIRED: LTTR 46 ENCL 45

HRC Form 355 US. NUCLEAR AKGULA'IORY COMM/83/0/r IY 83(

APPROVEO OMB NO 3)50010s LICENSEE EVENT REPORT (LER) KXP/RES, 8/31/88 FACILITE NAME II) DOCKET NUMBER I2) PAGE St. Lucie Unit IIl 0 5 0 0 0 3 3 5 1 OF INADVERTENT START OF 1C HIGH PRESSURE SAFETY INJECTION PUMP DUE TO ELECTRICAL TRANSIENT EVENT DATE ISI LER NUMBER (5) REPORT DATE (7) OTHER FACILITIES INVOLVED ( ~ )

MONTH OAY YEAR YEAR SEOUEHT/*L llsvrslcnr MONTH OAY YKAR PAC/LITY NAMES OOCKFT NUMBER(3)

HUM48/I NUMBER St. Lucie I)l 0 5 0 0 0

0. 2 0 5 88 88 001 0 0 0 3 0 7 8 8 NA 0 5 0 0 0 OPERATINO THIS REPORT IS SUBMITTED PURSVANT T0 THE REDUIREMENTB oF 10 cF R $ r Icnccc ons or mois o/ tns Iooowinc/ III MOOS (8) 20.402(hl 20 405(cl 50.73(s)12)(irl 73.7)(41 POWER 20.405(sl(I) 5) BOW(cl(I) 50.73(s l(2 lit) 73.71(cl LEYFL 1 0 0 20 SOS(sllll(al 50.38( ~ ) (2) l(2) (sit) DTHER ISoccify in Aortrsct I I0 I 50.73(s ociow snd in Tort, HRC form 20.408( ~ l(1)(BI) 50.73(sl(2) li) 50.73(s)(2 INiii)(Al JFFAI 20.405 4 I (I ) Or I 50.73(sl(2) lii) 50.73(s) (21(HI/I IS I 20.405 4)(I I (r) 50.734)(2)(iiil 50.73( ~ I LT ) I4 I LICENSEE CONTACT FOR THIS LER (12I NAME TELEPHONE NUMBER J. W. Connor, Shift Technical Advisor AREA CODE 30 54 65- 3550 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

MANVFAC. EPORTABLE MANUFAC CAUSE SYSTEM COMPONENT TO NPRDS SYSTEM COMPONENT TVRER TURER g;>Pg~ > ~AF

>~jPFV@j SUPPLEMENTAL REPORT EXPECTED (IO MONTH OAY YEAR KXPECTFO SUBMISSION DATE I15)

YES IIIycr. compN/s EXPfCTED SVSMISSIOH OATfl NO ABSTRACT ILimit to tc00 roscsr. Is.. soorosimctcry /if/son r/nore.roots tyocwnttsn /incr/ l18)

While Unit 1 was at 100% power, Mode 1, the "C" High Pressure Safety Injection (HPSI) pump started due to a spurious trip and immediate reset of a breaker on a 120 VAC instrument buss. The Operations Department was investigating a ground indication which led them to this breaker (the ground was found subsequently in a safety injection tank sample valve indicating light). The breaker appeared in the tripped position and when the operator touched the breaker it tripped. He immediately reset the breaker. The Reactor Control Operator (RCO) saw the pump indicate a start. He verified that it was a spurious start and stopped the pump.

There were no safety consequences of the event as the reactor remained at 100%

power and no water was injected to the Reactor Coolant System (RCS). Corrective actions include: replacement of the breaker, coordination with the manufacturer of the safeguards equipment to evaluate the response of the equipment, and testing the equipment to assure proper operation.

SS03ii0151 SS0307 05000335 F'DR ADOCK S DCD NRC Form 345 i9 83)

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NRC Form 3ddA U,S, NUCLEAR REGULATORY COMMISSION (9 83)

LICENSEE EVE T REPORT (LER) TEXT CONTINUATI APPROVED OM8 NO 3) SONICS EXPIRESI 8/31/88 FACILITYNAME II) OOCKET NUMEER LT) LER NUMEER )8) PAGE )3)

EI'I YEAR SEGVENTIAL .I,,K REVISION St. Lucie Unit Nl oRS'VMSE/I "..?n NI/MSER o s o o o 335 88 0 1 0 0 02 OF 03 TEXT llfmo/s sPscs r's /odrrdsd. Ir>> sddidosrs/H/IC %%drm 38//A') I17)

EVENT DESCRIPTION The Operations Department was in the process of troubleshooting a ground on the 120 VAC system per ONOP 1-0960030. While executing the procedure, the operator noticed that the operating lever that trips and resets breaker NS, on the MA instrument buss (EIIS:EJ), appeared tripped. He called this to the attention of the Assistant Nuclear Plant Supervisor (ANPS) wh'o went to investigate. The ANPS agreed that the breaker appeared tripped and touched it to verify this.

When the ANPS touched the breaker it opened. The ANPS immediately reset the breaker. In the control room, bistable trips were received on Engineered Safety Features Actuation System (ESFAS) (EIIS:JE) channel MA for: Safety Injection Actuation Signal (SIAS) on containment pressure, Containment Spray Actuation Signal (CSAS) on containment pressure, Containment Isolation Signal (CIS) on containment pressure, and Recirculation Actuation Signal (RAS). The Reactor Protection System (RPS) channel A indicated a trip for high containment pressure as is expected since this trip comes from the same instrument loop as the ESFAS bistable. The Sequence Of Events Recorder (SOER) showed SIAS trip and immediate reset for channels A and B. Only the 1C HPSI pump (EIISEBQ) started and was stopped by the RCO approximately 40 seconds later. No other engineered safety feature equipment was actuated. All alarms and trips were reset and the plant returned to normal. Although the Sequence Of Events Recorder indicated a SIAS on both A and B channels, SZAS was not locked in and did not require resetting.

CAUSE OF EVENT A systematic evaluation of this event was performed and it was concluded that the spurious trip of circuit (IS breaker on 120 VAC instrument buss MA and immediately resetting it, to be the most likely cause of the safeguards actuation. The resulting voltage transient on the instrument buss apparently caused the bistables to trip and perturbed the trip logic to produce a momentaryRA" trip signal. The Sequence of Events Recorder shows that the trip signal for the side was present for only .022 seconds which is less than the .030 seconds required to lock in the SIAS trip. The trip signal for the,"B" side was in for .018 seconds. The reason that only the 1C HPSI pump started would seem to be a "relay race" associated with such a brief spurious signal. This also explains the reason for the SOER indication of a trip but not having to reset it. The reason for the SOER indication of a ",B" SIAS trip is still under investigation.

ANALYSIS OF EVENT were no safety consequences of the event as the .reactor remained

'here at 100%

power and no water was injected to the RCS by the High Pressure Safety Injection pump. Were this event to occur during other modes of operation, there would still be no safety consequences as Plant Technical Specifications require disabling the possibility of a low HPSI pumps as RCS temperature decreases to preclude temperature overpressure situation.

NRC FORM SSSA IESS)

,gj NRC Form 3ddA U,S. NUCLEAR RECULATORY COMMISSICrr (9E)3)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMB NO 3150-0)OS EXPIRES: 8/3(/88 PACILITY NAME (I) OOCKET NUMEER (3) LER NUMBER (EI PAGE (3)

YEAR $ g8~ SECUENTIAL )Y REvrdroa CCr'UMdea r/VMeea St. Lucie Unit fl 0 5 0 0 0 8 8 0 01 00 03 OFO 3 TExT /// mors spssp is l)r)r)irsr/ r/ss s(fel)r)s/NIFc Form JRLI'5/ (17)

CORRECTIVE ACTIONS

l. Replacement of the breaker would necessitate de-energizing the MA instrument buss power to the ESFAS cabinets. This is considered undesirable during power operation. However, the Electrical Maintenance Department has visually inspected the breaker and found no evidence of damage.

2. The Electrical Maintenance Department will remove the breaker during the next reactor shutdown and replace it.

3. Electrical Maintenance will then coordinate with the manufacturer of the breaker to find out if indeed there is a problem with the breaker and if it may pose additional concerns.

4. The I a C Department has checked the operation of the ESFAS equipment and has found it working properly. They have performed a check on the power supplies to the trip circuitry and found them to be satisfactory. The automatic test circuitry also indicates no problems.

5. I & C Maintenance is presently working with the manufacturer of our ESFAS system to determine why the system responded as it did. Preliminary conversations with the ESFAS supplier indicate that the rapid cycling of breaker 18 may have caused a spike that lasted long enough to register on the Sequence of Events Recorder and start the pump, but not long enough to lock in and cause a complete safety injection actuation signal. The supplier of the ESFAS system will continue to look into this actuation. I (' Maintenance will follow up on this investi-gation.

6. A functional test to verify that the system performs to its design basis will be conducted when the plant is in a suitable configuration during the next refueling outage.

ADDITIONAL INFORMATION Com onent Failures NONE The breaker has not been examined yet.

Previous Similar Events For a previous spurious Engineered Safeguard Actuation, although an unrelated cause, see LER 335-87-03.

NRC FORM SddA (9S)3)

MARQUE '7 1988 L-88-110 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Gentlemen:

Re: St. Lucie Unit 1 Docket No. 50-335 Reportable Event: 88-01 Date of Event: February 5, 1988 Inadvertent Start of 1C High Pressure Safety In'ection Pum Due to Electrical Transient The attached Licensee Event Report is being submitted pursuant to the requirements of 10 CFR 50.73 to provide notification of the subject event.

Very truly yours, W. . Con ay Acting Group Vice President Nuclear Energy WFC/GRM/gp Attachment cc: Dr. J. Nelson Grace, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St. Lucie Plant GRM/001. LER an FPL Group company