05000382/LER-1986-001, :on 860107,reactor Trip Occurred on Dropped Control Element Assembly (Cea).Caused by Faulty Automatic CEA Calculator Timing Module.Card Replaced on 860123 & Sent to C-E for Evaluation

:on 860107,reactor Trip Occurred on Dropped Control Element Assembly (Cea).Caused by Faulty Automatic CEA Calculator Timing Module.Card Replaced on 860123 & Sent to C-E for Evaluation

ML20151W500
Person / Time
Site:	Waterford
Issue date:	02/06/1986
From:	Cook K, Tanya Smith LOUISIANA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION (ADM), Office of Nuclear Reactor Regulation
References
LER-86-001, LER-86-1, W3P86-0024, W3P86-24, NUDOCS 8602120080
Download: ML20151W500 (4)

LER-1986-001, on 860107,reactor Trip Occurred on Dropped Control Element Assembly (Cea).Caused by Faulty Automatic CEA Calculator Timing Module.Card Replaced on 860123 & Sent to C-E for Evaluation

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(iv), System Actuation
3821986001R00 - NRC Website

text

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NRC r d 3ee u.$. NUCLEAR LEIULATORY COMMISSION APPROVEO OMe NO. 31So4to4 Ecl2ES. S/3086 LICENSEE EVENT REPORT (LER)

FACILITV NAME (1) e DOCKET NUMBER (2)

PAuf G Waterford Steam Electric Station Unit'3 015 l 010 l o l 31812 1 lOFl013 TITLE to)

Reactor Trip on Dropped Control Element Assemb1v EVENT DATE (8)

LER NUMSER 48)

REPORT DATE (7)

OTHER FACILITIES INVOLVED (8)

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MONTH DAY YEAR FActLITV N AMEs DOCKET NUM8ER($l MONTH DAY YEAR YEAR N/A 0l5l0l0l0l l l 0l1 0l7 8

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NAME TELEPHONE NUMBER AREA CODE T. Smith, Maintenance Superintendent 51 014 41614I-1 3111318 COMPL ETE ONE LINE FOR EACH COMPONENT PAILURE DESCRISED IN THl3 REPC817 H3)

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w osi ABSTRACT At 1452 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.52486e-4 months <br /> on January 7, 1986 Waterford Steam Electric Station Unit 3 was operating at 100% reactor power for the previous 14 days when a reactor trip occurred on low Departure from Nucleate Boilire Ratio (DNBR). Upon stabilizing plant conditions in mode 3 (hot standby), operations personnel attributed the reactor trip to the inadvertent dropping of Control Element Assembly 31.

Due to the penalty factors associated with this Control Element Assembly, the Core Protection Calculators (EIIS System Code AA) initiated a low DNBR trip.

The event has been attributed to a faulty Automatic Control Element Assembly Calculator Timing Module (EIIS Component Code TMR). Troubleshooting failed to detect any anomallies within the card; however, the card has been sent to Combustion Engineering for evaluation.

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NARRATIVE

At 1452 hours0.0168 days <br />0.403 hours <br />0.0024 weeks <br />5.52486e-4 months <br /> on January 7, 1986 Waterford Steam Electric Station Unit 3 was operating at 100% reactor power for the previous 14 days when a reactor trip occurred on low Departure from Nucleate Boiling Ratio (DNBR) (The signal emanates from the' Core Protection Calculators, EIIS System Code JC.).

Upon receiving the reactor trip, operations personnel entered procedures OP-902-000,

" Emergency Entry Procedure" and OP-902-001, " Uncomplicated Reactor Trip Recovery Procedure". Plant conditions were subsequently stabilized in mode 3 (hot standby).

An investigation immediately following the trip indicated that Control Element Assembly 31 (part length rod) (EIIS System Code AA) may have inadvertently fallen into the core. Due to the design of the Core Protection Calculators, a sufficiently large penalty factor was generated to trip the unit.

SAFETY CONSEQUENCES AND IMPLICATIONS

l The above event resulted in an actuation of the Reactor Protettive System in which no primary system parameters were exceeded. Since the Con *.rol Element Assemblies and the Reactor Protective System (EIIS System Code JC) functioned as designed, the event in no way placed Waterford 3 in a degraded safety condition.

CORRECTIVE ACTION

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An investigation indicated the reactor trip was due to the inadvertent dropping of Control Element Assembly 31.

It is suspected that the dropped rod was due to a faulty Automatic Control Element Assembly Calculator Timing Module (The ACTM card monitors and analyzes electrical currents within the Control Rod Drive NTC FOIM 364A C $3D

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DOCKET NUMEER (2)

LER NUMSER (6)

PaGE (3)

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Mechanism) (EIIS Component Code TMR); however, an inspection of the card did not reveal any signs of damage.

In addition, maintenance personnel monitored coil currents within the system. The results of this test proved satisfactory.

The subject card was replaced on January 23, 1986 and sent to Combustion Engineering for evaluation.

SIMILAR EVENTS

None PLANT CONTACT T. Smith, Maintenance Superintendent, 504/464-3138.

NEC FOCM 366a

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E POWER & LIGHT Louisiana me o<mecNoe s1e<<1 P O. BOX 6008

• NEW ORLEANS, LOUISIANA 70174. (SO4) 366-2345 U $ N iYSSE February 6, 1986 W3P86-0024 A4.05 QA Director, Office of Nuclear Reactor Regulation ATTENTION: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555 Subject: Waterford 3 SES Docket No. 50-382 License No. NPF-38 Reporting of Licensee Event Report

Dear Sirs:

Attached is Licensee Event Report Number LER-86-001-00 for Waterford 3.

This Licensee Event Report is submitted per 10CFR50.73(a)(2)(iv).

Very truly yours, m

c/

K.W. Cook Nuclear Support & Licensing Manager KWC:GEW:sms Attachment i

cc:

R.D. Martin, G.W. Knighton, J.H. Wilson, NRC Resident Inspectors Office, INPO Records Center (J.T. Wheelock), B.W. Churchill, W.M. Stevenson Sr 9