ML18011B122

LER 96-016-00:on 951228,unplanned Esf/Rps Actuation Occurred Due to Unexpected Opening of a Rt Breaker During Testing. Caused by Inadequate Procedure.Revised Procedure & Trained Appropriate personnel.W/960129 Ltr

ML18011B122
Person / Time
Site:	Harris
Issue date:	01/29/1996
From:	Donahue J, Verrilli M CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HNP-96-011, HNP-96-11, LER-95-016-01, LER-95-16-1, NUDOCS 9602010112
Download: ML18011B122 (5)

Text

~ CATEGORY 1 REGULATORY INFORMATION DISTRIBUTION SYSTEM g (RIDS)

ACCESSlON N5R:9602010112 DOC.DATE: 96/01/29 NOTARIZED: NO DOCKET FACIL:50-400 Shearon Harris Nuclear Power Plant, Unit 1, Carolina 05000400 AUTH. NAME AUTHOR AFFILIATION VERRILLI,M. Carolina Power & Light Co.

DONAHUE,J.W. Carolina Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 96-016-00:on 951228,unplanned ESF/RPS actuation occurred due to unexpected opening of "A" RT breaker during testing.

Caused by inadequate procedure. Revised procedure & trained appropriate personnel.W/960129 ltr.

DISTRIBUTION CODE: ZE22T COPIES RECEIVED:LTR ENCL SIZE:

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

NOTES:Application for permit renewal filed. 05000400 G RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 PD 1 1 LE,N 1 1 INTERNAL: ACRS 1 1 AEOD SPD AB 2 2 AEOD/SPD/RRAB 1 1 FXjg R 1 1 NRR/DE/ECGB 1 1 NRR/DE/EELB 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 D RES/DSIR/EIB 1 1 RGN2 FILE 01 1 1 0

EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE,J H 2 2 NOAC MURPHY,G.A 1 1 NOAC POOREgW. 1 1 NRC PDR 1 1 NUDOCS FULL TXT 1 1 E

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

Carolina Power R Light Company Harris Nuclear Plant PO Box l65 JAN 2 9 l996 New Hill NC 27562 U.S. Nuclear Regulatory Commission Serial: HNP-96-011 ATTN: NRC Document Control Desk 10CFR50.73 Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 DOCFAT NO. 50-400 LICENSE NO. NPF-63 LICENSEE EVENT REPORT 95-016-00 Gentlemen:

In accordance with Title 10 to the Code of Federal Regulations, the enclosed Licensee Event Report is submitted. This report concerns an unexpected opening of the "A" Reactor Trip Breaker during testing, while the plant was shutdown in Mode-3. This occurrence constitutes an unplanned Reactor Protection System actuation.

Sincerely, J. W. Donahue General Manager Harris Plant MV Enclosure c: Mr. S. D. Ebneter (NRC - RII)

Mr. N. B. Le (NRC - PM/NRR)

Mr. D. J. Roberts (NRC - HNP) 9602010112 960129 PDR ADQCK 05000400 S PDR O~8O State Road H3A New Hill NC

NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB No. 3150-0104 l4 95) EXPIRES 04/30/SB ESTIMATED BURDEN PBI RESPONSE TO COMPLY WITH T)RS MANOATOAY INFORMATION COllECTION REOUEST: QLO HRS. REPOATED lESSOHS LEARNED AAE LICENSEE EVENT REPORT (LER) INCORPOAATEO INTO THE UCEHSING PAOCESS ANO FEO BACK TO INDUSTRY.

FORWARD COMMENTS REGAROOIG BURDEN ESTIMATE TO THE UIFOAMATIN ANO RECORDS MANAGEMENT BRANCH ITS F33L US. HUClEAR REGULATORY COMMISSION.

(See reverse for required number of WASHUIGTOH, OC 20555000l, ANO TO THE PAPBIWOAK REDUCTION PROJECT (3)50.

digits/characters for each block) 0104L OFFICE OF MANAGEMENT AND BUDGET, WASHINGTON, OC 205(KL FACIUTY NAME 11) OOCKH NUMeER 13) PACE )3)

Harris Nuclear Plant Unit-1 50-400 1 OF 3 TITLE )4)

Unexpected opening of the "A" Reactor Trip Breaker during testing, constitutes an unplanned ESFI)RPS actuation.

EVENT DATE (5) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (6)

FACIUTY NAME OOCKETNUM8ER SEOUENTIAL REVISION MONTH OAY YEAR YEAR MONTH OAY YEAR NUMBER NUMBER 05000 FACIUTY NAME OOCKETNUMBER 12 28 95 95 016 00 29 96 05000 OPERATING THIS REPORT IS SUBMITTED PUR SUANT To THE REQUIREMENTS OF 10 CFR B: (Check one o r more) (11)

MODE (9) 20. 2201 (b) 20.2203(a) (2) (v) 50.73(a)(2)(i) 50.73(a)(2)(viii)

POWER 20.2203(a) (1) 20.2203(a)(3) (i) 50.73(a)(2)(ii) 50.73(a) (2) (x)

LEVEL (10) 20.2203(a) (2) (i) 20.2203(a) (3)(ii) 50.73(a)(2)(iii) 73.71 20.2203(a) (2)(ii) 20.2203(a)(4) X 50.73(a)l2)(iv) OTHER 20.2203(a)(2) (iii) 50.36(c) (1) 50.73(a)(2)(v) S pecrfy in Abstract below or in NRC Form 366A 20.2203(a) (2)(iv) 50.36(c)(2) 50.73(a)(2) (vii)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUM8ER Urrorvde Area Code)

Michael Verrilli Sr. Analyst - Licensing (919) 362-2303 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DES CRIBED IN THIS REPORT (13)

REPORTABLE REPORTABIE CAUSE SYSTEM COMPONENT MANUFACTURER CAUSE SYSTEM 'COMPONENT MANUFACTURER TO NPROS TO NPROS SUPPLEMENTAL REPORT EXPECTED (14) MONTH OAY YEAR EXPECTED YES SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE). X NO DATE (16)

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

On December 28, 1995, with the plant shutdown in Mode-3 (Hot Standby) and control rods fully inserted, the "A" Train'Reactor Trip Breaker unexpectedly opened while performing logic testing on the "A" Train Solid State Protection System (SSPS). The opening of the breaker occurred when the SSPS Logic A Test Switch was returned to the "OFF" position after completing the test for the Pressurizer High Pressure Trip circuitry. This switch is a 23 position, rotary-type switch and during this particular test, was rotated in the clockwise direction from position 7 to the "OFF" position, instead of the most direct route to "OFF", which would have been counter-clockwise. Also, during this portion of the test, the Input Error Inhibit Switch was placed in the "NORMAL" position as procedurally directed. With the plant in Mode-3 and the Input Error Inhibit Switch in the "NORMAL" position, rotating the switch in the clockwise direction through positions 20 k, 21 satisfied SSPS logic conditions for generating a reactor trip signal, opening the trip breaker. To determine the cause and ensure that the trip breaker had opened as a result of the testing being performed, Instrument and Control Technicians repeated the applicable portions of the procedure two additional times to recreate the appropriate conditions.

The trip breaker again opened during both of these subsequent evolutions. The reactor trip breaker openings were not accompanied by any other Reactor Protection System or Engineered Safety Feature actuation signals.

The cause nf the initial trip breaker opening was procedural inadequacies in the SSPS logic test procedure. The cause of the two subsequent openings was personnel error. Corrective actions for this event will include procedure revisions and training for appropriate personnel.

NRC FORM 36BA US. NUCLEAR REGULATORY COMMISSION (499)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (I) DOCKET LER NUMBER (9) PAGE g)

OUENTIAL REVISION TEAR NUMBER NUMBER Shearon Harris Nuclear Plant - Unit N1 50400 2 OF 3 95 016 - 00 TEXT Pf met opooo ro nqvdod, oso oddi5ml oopio ol //RC Fnm 3BQI (IT)

EVENT DESCRIPTION:

On December 28, 1995, the plant was shutdown in Mode-3 (Hot Standby), with control rods fully inserted.

During "A" Train Solid State Protection System (SSPS, EIIS Code-JG) logic testing (MST-I0001), the "A" Reactor Trip Breaker unexpectedly opened at 1430 hours0.0166 days <br />0.397 hours <br />0.00236 weeks <br />5.44115e-4 months <br />. The opening of the breaker occurred when the SSPS Logic A Test Switch (EIIS Code-JG 33) was being returned to the "OFF" position after completing the test for the Pressurizer High Pressure Trip circuitry. This switch is a 23 position rotary-type switch, which based on discussions with Instrument & Control (I&C) Technicians, had historically been returned to the "OFF" position by counter-clockwise rotation (the shortest and most direct route to "OFF"). During this test, Instrument and Control (I&C) Technicians returned the switch to "OFF" by clockwise rotation. The change in rotational direction was recommended by engineering personnel to reduce the possibility of residue build-up on the switch contacts. Also, during this portion of the test, the Input Error Inhibit Switch (EIIS Code-JG 33) was in the "NORMAL" position as per the test procedure.

Following the unexpected breaker opening, in an effort to determine the cause and ensure that the trip breaker had opened as a result of the testing being performed, I&C Technicians repeated the applicable portions of the procedure two additional times to re-create the appropriate conditions. The trip breaker again opened during both of these subsequent evolutions. At this point, testing was secured to discuss the occurrence with Operations personnel in the main control room and develop a troubleshooting plan.

Investigation into this occurrence revealed that with the plant in Mode-3 and the Input Error Inhibit Switch in the "NORMAL" position, rotating the switch in the clockwise direction through positions 20 & 21 satisfied SSPS logic conditions for generating a reactor trip signal, opening the trip breaker.

The reactor trip breaker openings were not accompanied by any other Reactor Protection System (RPS) or Engineered Safety Feature actuation signals but were determined to be unplanned RPS actuations. A four hour non-emergency report per 10CFR50.72(b)(2)(ii) was made to the NRC at 1717 hours0.0199 days <br />0.477 hours <br />0.00284 weeks <br />6.533185e-4 months <br /> on December 28, 1995.

CAUSE:

The cause of this event was procedural inadequacies. The SSPS Logic Test surveillance procedure (MST-I0001) did not address the possibility that a reactor trip signal would be generated at switch. positions 20 &

21 if the test was performed in Mode-3 when turbine trip signals are present due to the plant being shut down, and with the Input Error Inhibit Switch in the "NORMAL" position. It also did not specify which direction the test switch should be turned when returning it to the "OFF" position. Investigation into this event revealed that a revision was performed to procedure MST-I0001 following a plant modification in 1985 that inserted the guidance to place the Input Error Inhibit Switch in the "NORMAL" position rather than in the "INHIBIT" position, which was required for P-4 Permissive voltage verification. The above described circumstances that resulted in generating the reactor trip signal were apparently not considered in 1985 during the procedure revision process. The procedure deficiency has remained undetected since 1985 due to the plant normally being in Mode-1 during this test and the switch being rotated counter-clockwise, thus avoiding position 20 & 21.

Also, based on an interpretation of a precaution and limitation in MST-I0001, the I&C technicians deviated from the prescribed test sequence to investigate the condition following the initial unexpected opening of the trip breaker, instead of stopping to develop a troubleshooting plan. This practice resulted in the two subsequent trip breaker openings and was considered as personnel error. Though this error was cognitive in nature, the I&C technicians involved were attempting to gather as much information as possible, prior to informing and discussing the occurrence with the Operations Shift Supervisor in the main control room.

A(-

RRC FORM 366A US. NUCKLR REGUIATORT COMMISSION

)4.65)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACIUTT K)AINE'(I) DOCKET EER NUMBER )6) PAGE )3)

SEOUENTIAE RET5)ON NUMBER NUMBER Shearon Harris Nuclear Plant Unit 0'1 50400 3 OF 3 95 - 016 - 00 TEXT lrl vroco spoco rs ssrrviod, vso odditkuvl coper ol HRC Furm 36QI (I 1)

SAFETY SIGNIFICANCE:

There were no safety consequences as a result of this event. The plant was shutdown with control rods fully inserted in the core and the reactor trip breaker functioned as designed. Had this test been performed at power, SSPS logic conditions would not have been satisfied to generate a reactor trip signal, due to the absence of turbine trip signal inputs.

PREVIOUS SIMILAR LERs:

No similar LERs have been reported pertaining to an unplanned Reactor Protection System actuation while shutdown.

CORRECTIVE ACTIONS COMPLETED:

1 Procedure revisions were completed for MST-I0001, MST-I0320, MST-I0072 and MST-I0073 to ensure

~

that the Input Error Inhibit switch is placed in the "INHIBIT"position any time that the Logic Test Switch is removed from the "OFF" position. These revisions were completed on January 26, 1996.

2. Management expectations were communicated to appropriate plant personnel regarding the importance of stopping work or testing activities when unanticipated occurrences are encountered. Items emphasized included requirements for developing and executing a troubleshooting plan in accordance with plant troubleshooting procedure MMM-027 and the need for clear and complete communications. This was completed on January 26, 1996.

EIIS CODES:

Solid State Protection System - JG