ML18038B923

LER 97-002-00:on 970626,discovered That Four Surveillance Instructions (Sis) Did Not Fully Test All Relay Logic Combinations.Caused by Personnel Error.Verified Relay Contacts Operable & Revised Applicable SIs.W/970725 Ltr

ML18038B923
Person / Time
Site:	Browns Ferry
Issue date:	07/25/1997
From:	Crane C, Jay Wallace TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
GL-96-01, GL-96-1, LER-97-002-04, LER-97-2-4, NUDOCS 9708010256
Download: ML18038B923 (18)

Text

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REGULATORY INFORMATION DISTRlBUTION SYSTEM (RIDS)

ACCESSION NBR:970803.0256 DOC..DATE: 97/07/25 NOTARIZED: NO DOCKET ¹ FAC :50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUTH.NAi>E AUTHOR AFFILIATION WAL'ACE,J.E. Tennessee. Valley Authority CRANE,C.M. Tennessee Valley .Authority REC.P.NAME RECIPIENT AFF I L IAT ION

SUBJECT:

LER 97-002-00:on 970626,discovered that four Surveillance Instructions (SIs) did not fully test all relay logic Caused by personnel error. Verified relay contacts operable & revised applicable SIs.W/970725 ltr.

'ombinations.

DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL i SIZE:

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

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-3-PD 1 1 WILLIAMSiJ. 1 1 ZNTERNAL: ACRS 1 1

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AEOD/SPD/RRAB NRR/DE/ECGB 1 NRR/DE/EELB 1 1 NRR/DE/EMEB , 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HI CB 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 EXTERNAL: L ST LOBBY WARD 1 1 LITCO BRYCE,J H 1 1 NOAC'OORE,W. 1 1'OAC QUEENER,DS

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1 NRC PDR 1 1 NUDOCS NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE'ASTE! 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 25 ENCL 25

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Tennessee Valley Authority, Post Office Box 2000, Decatur. Alabama 35609-2000 Christopher M. (Chris) Crane Vice President, Browns Ferry Nuclear Plant July 25, 1997 10 CFR 50.73 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555

Dear Sir:

BROWNS FERRY NUCLEAR PLANT (BFN) UNITS 2 r 'AND 3 DOCKET NOS 50 260 r aI1CI 296 FACILITY OPERATING LICENSE DPR 52 I AND 68 LICENSEE EVENT REPORT 50-260/97002 The enclosed report provides details concerning an inadequate surveillance instruction discovered during a review associated with Generic Letter 96-01, "Testing of Safety-Related Logic Circuits." This report is submitted in accordance with 10 CFR 50.73 (a)(2)(i)(B) as a condition prohibited by the plant's Technical Specifications.

Sincerely, C. N. ane cc: See page 2 1, ~

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PDR ADQCK 05000260 S PDR

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U.S. Nuclear Regulatory Commission Page '2 July 25, 1997 Enclosure cc (Enclosure):

Mr. Mark S. Lesser, Branch Chief U.S. Nuclear Regulatory Commission 61 Forsyth Street, S. W..

Suite 23T85 Atlanta, Georgia 30323 NRC Resident inspector Browns Ferry Nuclear Plant 10833 Shaw Road Athens, Alabama 35611 Mr. J. F. Williams, Project Manager U. S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike Rockville, Maryland 20852

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NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB NO. 3150%104 (4-95) EXPIRES 04/30/98 ESTIMATED BURDEN PER RESPONSE TO COMPLY WITH THIS MANDATORYINFORMATION COLLECTION REQUEST:

50.0 HRS. REPORTED LESSONS LEARNED ARE LICENSEE EVENT REPORT (LER) INCORPORATED INTO THE UCENSING PROCESS AND FED BACK TO INDUSTRY. FORWARD COMMENTS REGARDING (See reverse for required number of BURDEN ESTIMATE TO THE INFORMATIONAND RECORDS digits/characters for each block) MANAGEMENT BRANCH (TW F33). U.S. NUCLEAR REGULATORY COMMISSION. WASHINGTON, DC 205554001, FACIUTY NAME 11) OOCKST NUMBER (T) PAGE ta)

Browns Ferry Nuclear Plant (BFN) Unit 2 05000260 1 OF 6 TITLE Ie)

During Generic Letter 96-01 review, inadequate RHR surveillance instructions were discovered. These Sls resulted in not fully testing RHR TS logic circuits Root cause was personnel error in that the Sls were not properly revised.

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

FAaLITV NAME SEQUENTIAL REVISION MONTH DAY YEAR MONTH DAY YEAR 05000296 NUMBER NUMBER BFN Unit 3 FAaUTY NAMF 6 26 97 97 002 00 7 25 97 OPERATING THIS REPORT IS SUBMITTED PURS UANT TO THE REQUIREMENTS OF 10 CFR: (Check one ormore) (

MODE (9) 20.2201(b) 20.2203(a)(2)(v) x 50 73(a)(2)(I) 50.73(a)(2)(

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

POWER LEVEL (10) 100 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) 50.73(a) (2)(iv) OTHER 50.36(c) (1) 50.73(a)(2)(v) Specify In Abstract below 20.2203(a)(2)(iii) or in NRC Form 366A 20.2203(a)(2)(tv) 50.36(c)(2) 50.73(a)(2)(vii)

LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NuMBER IIIKrode Area Code)

James E. Wallace, Ucensing Engineer (205) 729-7874 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

REPORTABLE REPORTABLE CAUSE SYSTEM COMPONENT MANUFACTURER CAUSE SYSTEM COMPONENT MANUFACTURER TO NPRDS TO NPRDS SUPPLEMENTAL REPORT EXPECTED (14) MONTH DAY YEAR EXPECTED YEs SUBMISSION (If yes, complete EXPECTED SUBMISSION DATE).

X NO DATE (15)

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

On June 26, 1997, at "1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br />, a team performing reviews of Surveillance Instructions (Sls) in conjunction with Generic Letter 96-01, Testing of Safety-Related Logic Circuits," discovered that four Sls (Functional Testing of RHR Loop I and Loop II Valve Logic and Interlocks) did not fully test all relay logic combinations. Specifically, relay contacts for the reactor recirculation pump discharge isolation valve automatic closure logic were not tested. The root cause of this event was personnel error in that applicable Sls were not properly revised. This oversight occurred when the original Sls, which were performed during outages, were revised to allow the Sls to be performed while the units were in operation. These revisions occurred in June 1992 and September 1995 forUnits 2 and 3, respectively. Corrective actions include: (1) Work Orders (WOs) were written to verify the relay contacts were operating properly. The WOs were successfully completed by 2253 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.572665e-4 months <br /> and 2300 hours0.0266 days <br />0.639 hours <br />0.0038 weeks <br />8.7515e-4 months <br /> on the discovery date. (2) Applicable Sls will be revised prior to their next performance to ensure that the relay contacts are adequately tested.

The review of Sls in response to Generic Letter (GL) 96-01 is complete. A previous LER (259/97002) identified a similar GL 96-01 oversight for the CREV system.

NRC FORM 366 (4-95)

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NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4.95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME 1 DOCKET LER NUMBER ( )

NUMBER NUMBER Browns Ferry Unit 2 05000260 2 of 6 97 002 00 TEXT (I mors space ra required, use a diuona copies o orm (17)

PL'ANT CONDZTZONS At the time of the discovery of the condition, Units 2 and 3 were at 100 percent power. Unit 1 was shutdown and defueled.

ZZ. DESCRZPTZON OF EVENT A. Event On June 26, 1997, at .approximately 1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br /> Central Daylight Time (CDT), a review of RHR [BO] system logic functional tests for Generic Letter (GL) 96-01 was being performed. It was discovered that the reactor low pressure (<230 psig) inputs to the recirculation '[AO] pump discharge valve logic were not properly tested. The channel A and B RHR relay [RLY] contacts 3-4, which provide Division I input. to Division II logic, and the similar contacts, which provide Division II input to Division I logic, were not verified closed when their respective relays were energized. This oversight occurred. when the original SIs, which were performed during outages, were revised to allow the SIs to be, performed while the units are in operation. These revisions occurred June 1992 and September 1995 for Units 2 and 3, respectively.

At 1728 hours0.02 days <br />0.48 hours <br />0.00286 weeks <br />6.57504e-4 months <br />, Units 2 and 3 entered 24-hour Techni'cal Specifications Limiting Conditions for Operations (LCO) per Technical Specifications definition 1 OLL which was made

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effective from the time of discovery. These LCOs resulted from missed surveillance testing. Work orders were initiated to test contacts 3-4 for the four involved relays (10A-K90Ar K90Br

-K91A, -K91B for Units 2 and 3 (See Page 6 of 6). At 2253 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.572665e-4 months <br />, the relay contacts for Unit 2 were satisfactorily tested, and the Unit 2 LCO was exited. At 2300 hours0.0266 days <br />0.639 hours <br />0.0038 weeks <br />8.7515e-4 months <br />, the relay contacts for Unit 3 were satisfactorily tested, and the Unit 3 LCO was exited.

These SIs are required to be performed every 18 months or as required in accordance with Technical Specification 3.2.B (Testing of-Core.-and-Containment-Cooling Systems" initiation and control logic circuits).

This event is reportable in accordance with 10 CFR 50.73 (a)(2)(i)(B) as a. condition prohibited by the plant's Technical Specifications.

B. Zno erable Structures Co onents or S stems that Contributed to the Event:

None.

NRC FORM 366A (4.95)

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LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION PACILZTY NAME DOCKET PAGE NUMBER NUMBER Browns Ferry Unit 2 05000260 3 of 6 97 '002 -- 00 TEXT ( more space is required, use a diuona copies o orm 6 I17)

Dates and A roximate Times of Ma'or Occurrences:

June 1992 Unit 2 SIs were revised,. and steps to ful'ly test the channel A and B RHR logic were not incorporated.

September 1995 Unit 3 SIs were revised, and steps to fully test the channel A and B RHR logic were not incorporated.

June 26, 1997 at 1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br /> CDT The GL 96-01 review team discovered that RHR system logic circuits were not fully tested. Operations was notified'.

at 1728 hours0.02 days <br />0.48 hours <br />0.00286 weeks <br />6.57504e-4 months <br /> CDT Unit 2 and 3 entered 24-hour TS LCOs per TS Definition 1.0 LL. These LCOs were made effective from 1330 hours0.0154 days <br />0.369 hours <br />0.0022 weeks <br />5.06065e-4 months <br />.

at 2253 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.572665e-4 months <br />, CDT Unit 2 relay contacts were successfully tested; Unit 2 LCO was exited.

at 2300 hours0.0266 days <br />0.639 hours <br />0.0038 weeks <br />8.7515e-4 months <br /> CDT Unit 3 relay contacts were successfully tested; Unit 3 LCO was exited.

D. Other S stems or Seconda Functions Affected:

None.

E. Method of'iscove The defici'ent SIs were discovered by a GL review team. ~ This team compared SI acti'ons versus system logic drawings.

F. erator Actions:

None;

6. Safet S stem Res onses:

None.

ZZZ. CAUSE OF THE EVENT Zmmediate Cause:

The immediate, cause of the condition was deficient 'SIs ~ The SIs did not fully test all logic combinations for the reactor recirculation pump discharge isolation valve automatic closure function.

NRC FORM 366A (4-95)

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NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY HM4E DOCKET PAGE NUMBER NUMBER Browns Ferry Unit 2 05000260 4 of 6 97 -- 002 -- 00 TEXT ( moro space is required, use addiaona copies o orm I17)

B. Root Cause:

The root cause of this event was personnel error in that applicable SIs were not properly revised. A revision to the SIs inappropriately removed procedure steps which provided full testing of the channel A and B RHR logic for Units 2 and 3. This oversight occurred when the original SI which was performed during outages was revised to allow the SIs to be performed when a unit was on line.

Iv. ANALYSIS OF THE EVENT The affected circuit closes the reactor recirculation pump discharge valves in the event of a LOCA condition and coincident with a reactor vessel pressure less than 230 psig. Closure of the recirculation pump discharge valves ensures that LPCI flow is routed to the vessel through the jet pumps.

The common failure mode of these types of relays is coil failure and not contact failure. Although contacts 3-4 of relays 10A-K90A, 90B, 91A, and 91B were not tested during the performance of the SIs, the relay coils were tested through contacts 1-2. However, contacts 3-4 failed in the closed position, the logic would if still relay initiate when a signal was present. The only possible failure that would adversely affect the initiation logic would be a condition where contacts 3-4 would not close. 'These contacts provide a redundant start capability. Namely, contacts 3-4 of Division I relays give a Division II RHR LPCI initiation on the receipt of a Division I signal, and the same logic occurs in Division I with a Division II signal.

Contacts 3-4 make up the second half of the one-out-of-two-taken-twice logic (See Figures 1 and 2 on Page 6).

As a result of the WOs, which verified the proper operation of relay contacts 3-4, TVA believes that the valves .would have functioned as designed. In addition, there is no indication that this deficiency resulted or would have resulted in undetected equipment problems.

Consequently, there was no adverse impact on plant personnel or the public.

v. CORRECTIVE ACTIONS A. Immediate Corrective Actions:

WOs were initiated to test the affected relay contacts. WOs were successfully completed by 2253 hours0.0261 days <br />0.626 hours <br />0.00373 weeks <br />8.572665e-4 months <br /> and 2300 hours0.0266 days <br />0.639 hours <br />0.0038 weeks <br />8.7515e-4 months <br /> on the day of discovery.

B. Corrective Actions to Prevent Recurrence:

The review of logic system functional test SIs requested by GL 96-01 has been completed. This LER condition is the second deficiency NRC FORM 366A (4-95)

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~ NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISS(ON (4-95)

LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME ( DOCKET PAGE )

NUMBER NUMBER

'Browns Ferry Unit 2 05000260 5 of 6 97 -- 002 -- 00 TEXT ( more space rs reqwre, rrse a da>ona cop<as o orm (17) identified. Based on a previous LER (See Section VI.B), training actions and experience review activities for System Engineers relating to deficient SIs was performed. Applicable SIs will be revised prior to their next performance to ensure that the relay contacts are adequately tested.

VZ. ADDZTZONAL ZNFORMATZON Failed co onents:

None.

B. Previous LERs on Sind.lar Events:

LER 259/97002 described a similar failure for not fully testing the CREV initiation logic; This previous LER was also discovered by the GL 96-01 review team. At the time of the previous LER, the GL review was only 60 percent completed. No corrective actions taken in response to the previous LER would have precluded this latest LER (260/97002).

VZZ. COMMZTMENTS Applicable SIs will be revised prior to their next performance to ensure that the relay contacts are adequately tested.

Energy Industry Identification System (EIIS) system and component codes are identified in. the text with brackets (e.g., [XX) ) .

NRC FORM 366A (4-95),

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