ML17348B416

LER 92-001-00:on 920202,discovered That Rod Cluster Control Indicators Not in Agreement W/Demand Indication.Caused by Temp Variation in Indications Inherent to Sys design.In-core Flux Maps Performed & Indications adjusted.W/920302 Ltr

ML17348B416
Person / Time
Site:	Turkey Point
Issue date:	03/02/1992
From:	Hanek O, Plunkett T FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
L-92-51, LER-92-001-01, LER-92-1-1, NUDOCS 9203090195
Download: ML17348B416 (10)

Text

ACCELERATED DISTRIBUTION DEMONSTPA.TION SYSTEM t>

REGULATOF INFORMATION DZSTRZBUTTOIIYSTEM (RTDS)

ACCESSION NBR:9203090195 DOC.DATE: 92/03/02 NOTARIZED: NO DOCKET 5 I FACIL:.50-251 Turkey Point Plant, Unit 4, Florida Power and Light C 05000251 AUTH. NAME AUTHOR AFFILIATION HANEKF O. I. Florida Power & Light Co.

PLUNKETT,T.F. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 92-001-00:on 920202,discovered that rod cluster control indicators not in agreement w/demand indication. Caused by temp variation in indications inherent to sys design. In-core flux maps performed & indications adjusted.W/920302 ltr.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

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

NOTES NRR RAGHAVANFL 05000251 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-2 LA 1 1 PD2-2 PD 1 1 AULUCK,R 1 1 INTERNAL: ACNW 2 2 AEOD/DOA AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB10 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D NRR/DST/SICB8H3 1 1 NRR/DSg+SP B8D1 NRR/DST/SRXB 8E 1 1 RgG~FILE 02 RES/DSIR/EIB 1 1 RGN2-- F LE-'

EXTERNAL'G&G BRYCE F J H 3 3 L ST LOBBY WARD NRC PDR 1 1 NSIC MURPHYFG.A NSIC POORE,W. 1 1 NUDOCS FULL TXT NOTES: 1 1 NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EXT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31

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,P.O. Box 029100, Miami,~ FL,~ 33102-9100

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MAR 081392 L-92-51 10 CFR 50.73 U. S,. Nuclear Regulatory Commission Attn: Document Control Desk Washington; D. CD 20555 Gentlemen:

Re: Turkey Point Unit 4 Docket No. 50-251 Reportable Event: 92-001-00 Date of Event: February 2, 1992 Technical Specification 3.0.3 Entry Malfunction of Rod Cluster Control Position Indication The attached Licensee Event Report is being provided, pursuant to the requirements of 10 CFR 50.73, to provide information on the subject event.

Very truly yours,

// Plccu&yy hp WgQ T ~ F. Plunkett Vice President Turkey Point Nuclear TFPNQIH Attachment cc: Stewart D. Ebneter, Regi'onal Administrator, Region II, USNRC R. C'. Butcher, Senior Resident Inspector, USNRC, Turkey Point Plant C:,

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0 n LICENSEE EVENT REPORT (LER}

FACILITY NAME (1)

DOCKET NUMBER (2)

TURKEY POINT UNIT 4 05000251 1 OF 3 TECHNICAL SPECIFICATION 3.0.3 ENTRY ROD CLUSTER CONTROL POSITION INDICATORS NOT IN AGREEMENT WITH DEMAND INDICATION RPT DATE (I) OTHER FACILITIES INV, (6)

EVENT DATE (5) LER NUMBER (6)

SEQ 6 DOCKET 6 (S)

MON YR NAME 02 02 92 92 001 00 03 02 92 OPERATINC MODE (2) 1 0 CFR 5 0 . 7 3 a (Speciiy in Abetzect Deice and in text)

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LICENSEE CONTACT FOR THZS LER (12)

Olga I. Hanek, Licensing Engineer TELEPHONE NUMBER 305-246-6607 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

EXPECTED SUPPLEMENTAL REPORT EXPECTED (16) SUBMISSION DATE (1$ )

MONTH DAY YEAR (if yee, ccnplete EXPECTED SUBMISSION. DATE)

ABSTRACT ()6)

At approximately 1540, on February 2, 1992, with Turkey Point Unit 4 in Mode 3 and reactor coolant temperature at 547 degrees F, while pulling rods during Unit 4 reactor startup, rods J-11 and L-7 in Control Bank A and rod H-6 in Shutdown Bank B indicated'reater than 12 steps difference from the group step counters. The reactor went critical at 1600. After waiting the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> soak period, as allowed by Technical Specification 3.1.3.2, the rods still indicated misalignment.

Technical Specification 3.0.3 was entered at 1640 due to more than one Rod Position Indication (RPI) being out of service on a control bank (Control Bank A) as specified by Technical Specification 3.1.3.2.

Incore Flux Maps determ'ined all rods to be aligned properly. The RPIs were adjusted to indicate the rod positions properly and Technical Specification 3.0.3 for rods J-11 and L-7 was exited at 1725. At 1736, the RPI for rod H-6 was adjusted to indicate properly in accordance with Technical Specification 3.1.3.2. Technical Specification 3.1.3.2 action statement was exited at 1736.

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LZCENSEE NT REPORT (LER) TEXT )NTZNUATZON FACILITY NAME DOCKET NUMBER LER NUMBER PAGE NO.

TURKEY POINT UNIT 4 05000251 92-001-00 02 oF 03 I. DESCRIPTION OF THE EVENT At 1540, on February 2I 1992I Turkey Point Unit 4 was in Mode 3 with reactor coolant temperature at 547 F. While pulling rods during Unit 4 reactor startup, the Rod Position Indication (RPI) System indication for rods J-ll and L-7 in Control Bank A and rod H-6 in Shutdown Bank B indicated greater than 12 steps difference from the group demand step counters.

Technical Speci.'fication 3.1.3.2, "Reactivity Control Systems, Position Indication Systems Operating, Limiting Condition For Operation," states that the RPI System shall be operable and capable of determining the shutdown and control rod positions within + 12 steps of the group demand counters for withdrawal ranges of 0 30 steps and 200 228 steps, within one hour after rod motion (allowing for thermal soak) .

The reactor was declared critical at 1600. After waiting the 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> soak period as allowed by Technical Specification 3.1.3.2, rods J-11 and L-7 in Control Bank A still indicated a misalignment of greater than 12 steps with the control rod demand counter. Technical Specification 3.1.3.2, Action a.

allows for a maximum of one analog RPI per bank to be inoperable. Therefore, Technical Specification 3.0.3 was entered at 1640. For one analog RPI per bank inoperable, (rod H-6 in Shutdown Bank B), Technical Specification 3.1.3.2, Action a. requires determination of the position of the apparently misaligned rods by use of incore movable detectors. At the time of the end of the one hour soak the rods were still missaligned as follows:

Rod Bank Demand Counter RP I L-7 Control A 228 211 J-11 Control A 228 215 H-6 Shutdown B 228 215 Incore Flux Maps determined the Demand Counter indications to be correct at 228 steps and operable in accordance with Technical Specification 3.1.3.2.

Therefore, in accordance with 4-PMI-028.3, "RPI Hot Calibration, CRDM Stepping Test and Rod Drop Test," the RPIs were adjusted to properly indicate the rod positions at 228 steps. Technical Specification 3.0.3 for rods J-11 and L-7 was exited at 1725. Technical Specification 3.1.3.2 action statement for rod H-6 was exited at 1736.

II. CAUSE OF THE EVENT The root cause of this event is that rod position indication varies with temperature. This temperature variation was first identified at Turkey Point in 1972. In 1972 Westinghouse stated that temperature variations in indications are inherent to the design of the system. A special test was conducted at Turkey Point in 1975 to investigate the temperature dependent variations, but the results were inconclusive. Generally, the temperature dependent variation is corrected within the one hour thermal soak time allowed by Technical Specification 3.1.3.2.

Ik LICENSEE ZINT REPORT (LER) TEXT QINTINUATION FACZLITY NAME DOCKET NUMBER LER NUMBER PAGE NO.

TURKEY POINT UNIT 4 05000251 92-001-00 03 oF 03 III. ANALYSIS OF THE EVENT The operability of the RPls is required to determine control rod positions and thereby ensure compliance with the control rod alignment and insertion limits.

The requirements of Technical Specification 3.1.3.2 are intended to ensure that the potential effects of rod misalignment are bounded by the accident analyses. Incore flux maps determined all rods to be aligned properly. The RPIs were adjusted to indicate the rod positions properly, and Technical Specification 3.0.3 for rods J-1'1 and L-7 was exited at .1725. Technical Specification 3.1.3.2 action statement for rod H-6 was exited't 1736.

IV. CORRECTIVE ACTIONS 1., Incore Flux maps were performed and. determined the rods to be aligned properly.

2. In accordance with 4-PMI-028.3, the RPIs were adjusted to indicate properly.

3. A task team will review the system design to investigate possible system improvements. 1f the results of the investigation identify a root cause different from the root cause discussed in Section II of thi.s report, a supplement to the LER will be submitted.

V. ADDITIONAL INFORMS.TION No similar LERs have been identified.

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