ML17229A193

LER 96-007-00:on 961211,operation Prohibited by TSs Occurred Due to Inadequate Surveillance of MSIS Actuation Logic. Testing of MSIS High Containment Pressure 2/4 Actuation Logic Was Satisfactorily Performed on 961211.W/970109 Ltr

ML17229A193
Person / Time
Site:	Saint Lucie
Issue date:	01/09/1997
From:	Noble R, Stall J FLORIDA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-96-01, GL-96-1, L-97-007, L-97-7, LER-96-007-02, LER-96-7-2, NUDOCS 9701140028
Download: ML17229A193 (7)

Text

CATEGORY j.

REGULA Y INFORMATION DISTRIBUTIO YSTEM (RIDS)

ACCESSION NBR:9701140028 DOC.DATE: 97/01/09 NOTARIZED: NO DOCKET FACIL:50-389 St. Lucie Plant, Unit 2, Florida Power a Light Co. 05000389 AUTH. NAME AUTHOR AFFILIATION NOBLE,R.E. Florida Power & Light Co.

STALLPJ.A. Florida Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 96-007-00:on 961211,operation prohibited by TSs occurred due to inadequate surveillance of MISS actuation logic.

Testing of MSIS high containment pressure 2/4 actuation logic was satisfactorily performed on 961211.W/970109 DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR L ENCL TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:

j SIZE:

ltr.

E RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-3 PD 1 1 WIENSPL. 1 1 INTERNAL: ACRS 1 1 AE D B 2 2 AEOD/SPD/RRAB 2 2 FIL CENTER 1 1 NRR/DE/ECGB 1 1 E" EEGB 1 1 NRR/DE/EMEB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 NRR/DRCH/HQMB 1 1 NRR/DRPM/PECB 1 1 NRR/DSSA/SPLB 1 1 NRR/DSSA/SRXB 1 1 RES/DET/EIB 1 1 RGN2 FILE 01 1 1 D

EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE,J H 1 1 NOAC MURPHY,G.A 1 1 NOAC POORE,W. 1 1 0

NRC PDR 1 1 NUDOCS FULL TXT 1 1 N

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM OWFN SD-5(EXT. 415-2083) TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 26 ENCL 26

Florida Power st Light Compan,, P.O. Box 128, Fort Pierce, FL 34954.0128 January 9, 1997 L-97-007 10 CFR 50.73 U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D. C. 20555 Re: St. Lucie Unit 2 Docket No. 50-389 Reportable Event: 96-007 Date of Event: December 11, 1996 Operation Prohibited by Technical Specifications 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, J. A. Stall Vice President St. Lucie Plant JASIREN /

(

Attachment cc: Regional Administrator, USNRC Region II Senior Resident Inspector, USNRC, St. Lucie Plant

/1 3 i) 970ii40028 970i09 PDR ADQCK 05000389 S PDR an FPL Group companY

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED SY OMS No. 3160<104 EXPSIES IMISOISS

,(6-Se)

ESTIMATED BURDEN PER RESPONSE To COMPLY WITH THIS MANDATO INFORMATION COLLECTION REQUEST: 60J3 HRS. REPORTED LESSON LEARNED ARE INCORPORATED INTO THE UCENSINO PROCESS ANO F BACK TO SIDUSIRY. FORWAIO COMMDITS REOAROINO BURDEN ESTIMAT LICENSEE EVENT REPORT (LER) To THE INFORMATION AND RECORDS MANAGEMENT BRANCH IT% FSSI UW NUCLEAR REGIAATORY COMMISSION, WASHINOTON, DC 206664001 AND TO THE PAPERWORK REDUCTION PROJECT I316OO104L OFFICE 0 (See reverse for required number of MANAOEMENTAND BUOOET, WASHINOTON, DC 20603.

digits/characters for each block) fACIUTYNAME 111 DOCKET NQNSBI 121 PAOE Isl ST LUCIE UNIT 2 05000389 1 OF5 TITLE Iel Operation Prohibited by Technical Specifications Due to Inadequate Surveillance of MSIS Actuation Logic FACIUlYNAME DOCKET NUMBER MONTH OAY YEAR SEOUENTIAL REVISION NUMBER NUMBER MONTH OAY YEAR NIA FACIUlYNAME DOCKET NUMBER 12 11 96 96 007 00 9 97 NIA OPERATING MODE (B) 20.2201(b) 20.2203(a) {2)(v) 50.73(a)(2) 6) 50.73{a)(2)(viii)

POWER LEVEL {10) 20.2203(a) (2)(i) 20.2203(a) (3) {ii) 50.73(a) (2) (iii) 73.71 OTHER 20.2203(a) (2) (iii) 50.36(c)(1) 50.73(a)(2)(v) Specify In Abstract below or BI NRC Form 36SA 20.2203(a)(2) {iv) 50.36(c) {2) 50.73(a)(2)(vii)

NAME TELEPHONE NUMBER Snclude Area Codol Richard E. Noble, Licensing Engineer l561) 467 - 7022 CAUSE SYSTEM COMPONENT MANUFACTURER REPORTABLE REPORTABLE TO NPROS CAUSE SYSTEM COMPONENT MANUFACTURER TO NPRDS MONTH OAY YEAR EXPECTED YES SUBMISSION

{Ifyes, complete EXPECTED SUBMISSION DATE). X No DATE {15)

ABSTRACT (Umit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) {16)

On December 11, 1996, St. Lucie Unit 2 was operating in Mode 1 at 100 percent reactor power. While performing a review as requested by NRC Generic Letter 96-01, "Testing of Safety Related Logic Circuits." FPL determined that a deficiency existed in testing of the main steam isolation signal (MSIS) actuation logic on high containment pressure. Additional testing was immediately performed and completed satisfactorily.

The cause of the event was an inadequate surveillance procedure for testing the operation of the high containment pressure MSIS actuation logic. The surveillance procedure credited the observation of status lights on an automatic test insertion (ATI) device. The ATI status lights alone do not confirm tha a portion of the high containment pressure MSIS actuation logic was tested. This surveillance test procedure deficiency is not applicable to Unit 1, because the MSIS actuation logic for Unit 1 does not Include high containment pressure in its design.

Corrective actions include: 1) Additional testing was performed to confirm operability of the MSIS high containment pressure actuation logic. 2)The surveillance testing procedure was revised. 3) Additional safety related electrical circuitry is continuing to be reviewed with regard to testing adequacy in accordance with the actions requested in NRC Generic Letter 96-01.

NRc FoRM 368 Is.se)

NRC FORM 366A U.S. NUCLEAR RMULATORYCOMMISSI (4-96I LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST. LUCIE UNIT 2 05000389 2 OF 5 96 007 00 TEXT /ifmore speceis required, use edditionel copies of NRC Form 3MAi I17I On December 11, 1996, with St. Lucie Unit 2 operating in Mode 1 at 100 percent power, FPL engineering personnel determined that the high containment pressure actuation logic for the main steam isolation signal (MSIS) (EIIS:JE) may not have been adequately tested by current surveillance procedures. This determination was made based on an assessment of NRC Generic Letter, 96-01, "Testing of Safety Related Logic Circuits" for applicability to St. Lucie Plant.

St. Lucie Unit 2 Technical Specification (TS) Table 4.3-2, item 4c, requires that the MSIS logic be tested monthly. Instrument and control surveillance procedure 2-1400052, "Engineered Safeguards Actuation System Channel Functional Test", credits observation of the "utomatic test insertion (ATI) status lights for testing the MSIS actuation logic for high containment pressure. The ATI is a vendor supplied feature that inserts short duration pulses into the logic circuit and monitors the return pulses to confirm proper operation. If a monitored return pulse is not received, an ATI alarm will occur.

The MSIS logic is designed to actuate on low steam generator pressure or on high containment pressure. The MSIS actuation logic does not utilize its own high containment pressure bistables.

Instead, the output signals from the high containment pressure safety injection actuation signaI (SIAS) bistables are also wired to the MSIS 2/4 logic actuation modules (Refer to Figure 1). During the automatic testing of the SIAS high containment pressure bistables, ATI is not configured to look for a return pulse from the MSIS 2/4 actuation modules. Therefore, if the high containment pressure MSIS 2/4 actuation logic failed to operate in response to the injected pulse signals, no ATI alarm would be generated. The low steam generator pressure portion of the MSIS logic is verified during other portions of the ATI test sequence. Although the return pulse from high containment pressure MSIS actuation is not monitored by the ATI status lights and alarm, proper operation can be confirmed by observing the trip status lights on the MSIS 2/4 actuation modules. This surveillance test procedure deficiency is not applicable to Unit 1, because the MSIS actuation logic for Unit 1 does not include high containment pressure in its design.

On December 11, 1996, immediately following identification of the issue, proper operation of the MSIS actuation logic was confirmed by observing the MSIS 2/4 actuation module trip status lights during an ATI test sequence. Operations was notified of the issue via a St. Lucie Plant Condition Report.

Because a valid surveillance test was conducted concurrent with identification, Technical Specification (TS) Surveillance Requirement 4.0.3 was not entered. TS 4.0.3 specifies that failure to perform a surveillance requirement within the allowed surveillance interval shall constitute noncompliance with the operability requirements for a Limiting Condition for Operation (LCO).

The cause of the event was an inadequate surveillance test procedure. Operating Procedure 2-1400052, incorrectly credits the ATI status lights for testing the high containment pressure actuation logic of the MSIS. The ATI status lights alone do not provide an adequate test of this portion of the MSIS logic.

MAO FOAM 888A 14.961

c{'f NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSI I4-96I LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST. LUCIE UNIT 2 05000389 3 OF 5 96 007 00 TEXT llfmore speceis reriuired, use edditionel copies of NRC Farm 3MAJ I17)

This event is reportable under 10 CFR 50.73 (a)(2)(i)(B) as "any operation or condition prohibited by the plant's Technical Specifications'. St. Lucie Unit 2 TS Table 4.3-2, item 4c requires that the MSIS high containment pressure logic be tested monthly in modes 1,2, and 3. Based on the engineering review conducted for GL 96-01, the high containment pressure MSIS actuation logic was not fully tested by existing surveillance procedures. Concurrent with this discovery, proper operation of the high containment pressure initiation logic portion of the MSIS 2/4 actuation modules was verified by observation of the module status lights during an ATI test sequence. The surveillance procedure 2-1400052 has been revised to include the correct steps to verify operation of the 2/4 logic module status lights during the ATI sequence.

MSIS actuation is a functional unit of the engineered safety features actuation system (ESFAS) at St.

Lucie Plant. MSIS functions to close the main steam and main feedwater isolation valves in the event of a steam line break. The primary actuation signal for MSIS is low steam generator pressure. The high containment pressure actuation of MSIS provides a diverse actuation signal that is most significant for postulated small steam line breaks where steam generator pressure may remain above the MSIS setpoint for an extended period of time.

The existing surveillance procedure demonstrates operability of all but a small portion of the high containment pressure MSIS actuation logic. Specifically the high containment pressure 2/4 logic circuits, which are part of each MSIS 2/4 actuation module, are not verified by the surveillance procedure. The high containment pressure bistables and isolation modules, which input into the MSIS 2/4 logic modules, are'ommon with the SIAS logic which is tested by the ATI circuit every 27 seconds. The output side of the MSIS 2/4 actuation modules is also verified by ATI every 27 seconds during the low steam generator pressure portion of the MSIS logic test. The MSIS high containment pressure 2/4 logic is implemented using integrated circuits which are inherently more reliable than relay logic circuits. These integrated circuits are also tested during the 18 month integrated safeguards test, although each individual logic combination is not verified. Furthermore, observation of the MSIS 2/4 actuation module status lights demonstrated that the logic was in fact functional at time of discovery and, therefore, would have been functional in the past. Therefore, the health and safety of the public was not adversely affected by this event.

NRC FORM 388A I4.96I

NRC FORM seeA U.S. NUCLEAR RMULATORYCOMMISSIO

,I4-96)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST. LUCIE UNIT 2 05000389 4 OF 5 96 007 00 TEXT iifmore spaceis required, use additional copies of NRC Form 366AI I17I Testing of the MSIS high containment pressure 2/4 actuation logic was satisfactorily performed on December 11, 1996.

2. The St. Lucie Unit 2 Test Procedure {2-1400052) was approved on January 6, 1997 to include specific instructions for verification of the MSIS 2/4 actuation module trip status lights as part of the ATI check.

3. In accordance with Generic Letter 96%1, FPL is continuing to review applicable safety related logic circuitry and testing procedures to ensure that all circuit components required to be tested are adequately addressed by surveillance procedures.

None LER 389 96-005 "Operations prohibited by TS due to inadequate testing of Reactor Trip Breakers" This event describes an additional surveillance inadequacy identified during review performed per Generic Letter 96-01.

NRC FORM 388A (4.96I

NRC FORM 368A U.S. NUCLEAR REGULATORY COMMISSI I4-06)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION YEAR SEQUENTIAL REVISION ST. LUCIE UNIT 2 05000389 5 OF 5 96 007 00 TEXT /Ifmore speceis required, use edditionel copies of AfRC Form 366AJ I17I SIMPLIFIED MSIS ACTUATION LOGIC BISTABLE ISOLATOR STEAM MSIS GENERATOR A PRESSURE 2/4 LOGIC MODULE MSIS OUTPUTS MSIS 2/4 LOGIC MODULE BISTABLE ISOLATOR CONTAINMENT SIAS HIGH A PRESSURE 2/4 LOGIC MODULE SIAS OUTPUTS (Dt/COTOOM)