ML18022A754

Special Rept:On 891223,reactor Coolant Subcooling Monitor Declared Inoperable Due to Erratic Indications & Out of Svc Beyond 7-day Time Limit in Spec 6.9.2.Caused by Normal End of Life of Data Isolator Board.Board Replaced on 900103

ML18022A754
Person / Time
Site:	Harris
Issue date:	01/15/1990
From:	Richey R CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HO-900010-(O), NUDOCS 9001230200
Download: ML18022A754 (3)

Text

ACCELERATED DISTRIBUTION DEMONS TION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR: 9001230200 DOC. DATE: 90/01/15 NOTARIZED- NO DOCKET Shearon Harris Nuclear Power Plant, Unit 1, Carolina

'ACIL:50-400 05000400 AUTH. NAME AUTHOR AFFILIATION RICHEY,R.B. Carolina Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Special rept: on 891223,reactor coolant subcooling monitor declared inoperable due.to erratic indications.

DISTRIBUTION CODE IE22D COPIES RECEIVED LTR ENCL SIZE: D TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

S NOTES:Application for permit renewal filed. 05000400

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RECIPIENT COPIES RECIPIENT COPIES A ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 LA 1 1 PD2-1 PD 1 1 D BECKER, D 1 1 ACRS MOELLER 2 2 D INTERNAL: ACRS MICHELSON 1 1 ACRS WYLIE 1 1 AEOD/DOA 1 1 AEOD/DS P/TPAB 1 1 AEOD/ROAB/DSP 2 2 DEDRO 1 1 NRR/DET/ECMB 9H 1 1 NRR/DET/EMEB9H3 1 1 NRR/DET/ESGB 8D 1 1 NRR/DLPQ/LHFB11 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB11 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D NRR/DST/SPLB8D1 NUDOCS-ABSTRACT RES/DSIR/EIB 1

1 1

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1 1 ~ NRR/DST/SICB 7E NRR DS G

mCN2 FILE SRXB 8E F~ 01 1

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1 EXTERNAL: EG&G WILLIAMS,S 4 '

ST LOBBY WARD 1 1 LPDR 1 NRC PDR 1 1 NSIC MAYS,G 1 NSIC MURPHY,G.A 1 1 R NUDOCS FULL TXT 1 D

A D

D NOTE TO ALL "RIDS" RECIPIENTS:

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

TOTAL NUMBER OF COPIES REQUIRED: LTTR 38 ENCL 38

Carolina Power S Ught Company P. O. Box 165 ~ New Hill, N. C. 27562 R. B. RCHSY Manager Harrla Nuclear Prnject gQi g rJ 1990 Letter Number: HO-900010 (0)

United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 HARRIS NUCLEAR PROJECT UNIT 1 DOCKET NO. 50-400 LICENSE NO. NPF-63 NRC 14-DAY SPECIAL REPORT In accordance with Technical Specifications 3.3.3.6 and 6.9.2 for the Shearon Harris Nuclear Power Plant, Unit No. 1, Carolina Power & Light hereby submits this Special Report. This Special Report concerns the operability of the Reactor Coolant Subcooling Monitor.

Very truly yours, p s'~

R. B. Richey, Manager Harris Nuclear Project RBR:dgr'nclosure cc: Mr. R. A. Becker (NRR)

Mr. S. D. Ebneter (NRC RII)

Mr. J. E. Tedrow (NRC - SHNPP) 9001230200 900ii5 PDR ADOCK 05000400 PDC

<v'EM/H0-,9000100/1/Osl

REACTOR COOLANT SUBCOOLING MONITOR SPECIAL REPORT Descri tion of Event:

On December 23, 1989 at 0002, the Reactor Coolant Subcooling Monitor was declared inoperable due to erratic indications. This monitor is identified in the Shearon Harris Technical Specifications, Table 3.3-10, Item 11. The compensatory actions allow implementation of the alternative monitoring method, which is a manual calculation of RCS subcooling margin, to permit continued operation of the plant. This compensatory action was in place while the monitor was inoperable.

The monitor was out of service beyond the seven day limit, requiring a special report per Specification 6.9.2.

Cause/Corrective Actions:

The RCS Subcooling Monitor is a subroutine program of the main plant computer in the Safety Parameter Display System. The plant computer receives inputs from the "A" and "B" safety trains of incore thermocouples via an isolation device, a data isolator board. The computer program then calculates a subcooling margin value base on train "A" and "B" data, providing a single output to the SPDS display.

The data isolator board for the "B" safety train had failed due to normal end of life cause. The failure resulted in erratic high values of several incore thermocouples for the "B" train, causing the plant computer to improperly calculate the subcooling margin value. The failed board was replaced on January 3, 1990,

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restoring the monitor to operable status.

The repair was delayed due to the plant being in a refueling outage recovery and startup, and due to the holiday season' impact on personnel availability. Normally, equipment inoperabilities which are reportable after a specified time are identified and tracked at daily coordination meetings. This inoperability was not identified, however, until the seven day period had elapsed. The involved departments have been made aware of this situation, which is the first to have occurred in over three years of operation.

MEM/HO-9000100/2/Osl