ML18010A631

Special Rept:On 920420,RCS Subcooling Monitor Declared Inoperable to Install New & Improved Disk Drives in ERF Info Sys.Monitor Out of Svc for More than 7 Days.New Disk Drives & Circuit Board Upgrade Completed by Vendor on 920412

ML18010A631
Person / Time
Site:	Harris
Issue date:	05/08/1992
From:	Vaughn G CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9205140108
Download: ML18010A631 (4)

Text

ACCELERATED DEMONS'IaATION SYSTEM DISTRIBUTION REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9205140108 DOC.DATE: 92/05/08 NOTARIZED: NO DOCKET FACIL:50-400 Shearon Harris Nuclear Power Plant, Unit 1, Carolina 05000400 AUTH. NAME AUTHOR "AFFILIATION VAUGHN,G.E. Carolina Power & Light Co.

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

SUBJECT:

Special rept:on 920420,RCS subcooling monitor declared inoperable to install new & improved disk drives in ERF info I sys.Monitor out of svc for more than 7 days. New disk drives

& circuit board upgrade completed by vendor on 920412. D DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE: S TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:Application for permit renewal filed.

/

05000400 A

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID D CODE/NAME LTTR ENCL PD2-1 LA 1 1 PD2-1 PD 1 1 MOZAFARI,B. 1 .

1 D INTERNAL: ACNW 2 2 ACRS 2 2 S AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DET/EMEB 7E 1 1 NRR/DLPQ/LHFB10 1 1 NRR/DLPQ/LPEB10 1 1 NRR/DOEA/OEAB 1 1 NRR/DREP/PRPB11 2 2 NRR/DST/SELB 8D 1 1 NRR/DST/SICB8H3 1 1 R~R=:S PLB8D1 1 1 NRR/DST/SRXB 8E 1 1 EG=P - 02 1 1 RES/DSIR/EIB 1 1 RCF2 FILE 01 1 1 EXTERNAL: EG&G BRYCE,J.H 3 3 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHY,G.A 1 1 NSIC POORE,W. 1 1 NUDOCS FULL TXT 1 1 R D

A D

NOTE TO ALL "RIDS" RECIPIENTS:

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

TOTAL NUMBER OF COPIES REQUIRED: LTTR 32 ENCL 32

f CNILL Carolina Power & Light Company P.O. Box t65 ~ New Hill. NC 27562 G. E. VAUGHN Vice President Harris Nuctear Project NAY 6 >99P Letter Number: HO-920092 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 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 and Light hereby submits this Special Report. This Special Report concerns the operability of the Reactor Coolant: Subcooling Monitor.

Very Truly Yours, G. E. Vaughn Vice President Harris Nuclear Project MV:kjc Enclosure cc: Mr. S. D. Ebneter (NRC - RII)

Ms. B. L. Mozafari (NRC - RII)

Mr. J. E. Tedrow (NRC - SHNPP) 9205140108 'tt20508 PDR ADOCK 05000400 S PDR HEM/H0-920092/1/OS1 Yg&~~

Descri tion of Event:

0 On April 20, 1992 at 1431, the Reactor Coolant System (RCS) Subcooling Monitor was'eclared inoperable. This function is automatically performed by the plant process computer (Emergency Response Facility Information System - ERFIS). For the reasons described below, the RCS Subcooling Monitor was not restored until May 1, 1992 and is therefore being reported in accordance with the requirements of Technical Specification 6.3.3.3.c and 6.9.2 as a period of inoperability greater than seven days. Technical Specification compensatory measures, consisting of manual RCS subcooling calculations, were performed as required through the entire period of inoperability.

Cause Corrective Action:

The computer data disk drives have been a recent source of ERFIS reliability problems which resulted in a computer failure of greater than four hours and the required declaration of an Unusual Event per the Harris Emergency plan on April 14, 1992. To resolve this reliability problem and increase disk storage capacity, a planned outage for the computer was moved up on the schedule and began on April 20, 1992, to install new and improved disk drives. The original plan was to complete this repl'acement and subsequent post maintenance testing, in less than a one-week period. However, problems with one of the new disk drives plus our decision to run diagnostics and repair any hardware and software problems 'identified, caused the computer and thus the RCS Subcooling Monitor, to be out of service for greater than seven days. The ERFIS computer was returned to service on April 30, 1992 and after observing satisfactory operation for twenty four hours, was declared operable on May 1,1992.

With. the new disk drives and a computer printed circuit board upgrade to the most current revision level, which was completed by our computer vendor on April 2, 1992, it is our feeling that ERFIS reliability and therefore the reliability of the RCS Subcooling Monitor has been greatly improved.

MEM/HO-920092/2/OS1