ML072120325

Part 21 Notification - Failure of Enersys (Exide) Battery for North Anna, Units 1 & 2

ML072120325
Person / Time
Site:	North Anna
Issue date:	07/27/2007
From:	Shaub T Virginia Electric & Power Co (VEPCO)
To:	Joel Munday NRC/RGN-II
References
43527
Download: ML072120325 (3)

Text

OE.2 7/2O00- /US.Nuclear Regulatory,Commission Operations Center Event Report pqqe I Power Reactor Event# 43527 Site: NORTH ANNA Notification Date I Time: 07/27/2007 09:05 (EDT)

Unit: 1 2 Region: 2 State: VA Event Date / Time: 07/26/2007 (EDT)

Reactor Type: [1] W-3-LP,[2] W-3-LP Last Modification: 07/27/2007 Containment Type: DRY SUB DRY SUB NRC Notified by: TOM SHAUB Notifications: JOEL MUNDAY R2 HQ Ops Officer: MARK ABRAMOVITZ PART 21 (E-MAIL) NRR Emergency Class: NON EMERGENCY 10 CFR Section:

21.21 UNSPECIFIED PARAGRAPH Unit Scram Code IRX Crit Init Power Initial RX Mode Curr Power Current RX Mode 1i N Yes 100 Power Operation 100 Power Operation 2 N Yes 100 Power Operation 100 Power Operation PART 21 NOTIFICATION - FAILURE OF ENERSYS (EXIDE) BATTERY In March 2005, battery cell internal resistance for an EDG battery bank revealed five cells with abnormal resistance. "There was one cell for which no reading could be obtained and was replaced immediately. A second cell had a reading that was nearly four times the average of the associated string and was subsequently replaced as a proactive measure during the EDG maintenance outage. Three (3) other cells were noted with higher than average readings that are not considered to be operability concerns. In total, five (5) cells out of a total of 240 were found with higher than expected internal resistance values."

The failed battery was destructively tested revealing significant corrosion within the battery. The unit-2 batteries have been replaced. The unit-1 batteries will be replaced in the fall 2007 outage.

Manufacturer: Enersys (Exide)

Model: 3CA-5 Serial Number: beginning with 05 The licensee notified the NRC Resident Inspector.

Received at: 07/27/2007 09:03 Jul 27 2007 8:30 DOMINION 8042733715 7/ p.I PAGE 1 OF 2 NR.C FORM 381 U.S. NUCLEAR REGULATORY COMMISSION SPLOPERATIONS CENTER iEVENT

-- EENT NOTIFICATION OTNREACT&IR PLAINTE WORKSHEET EN#

3-127 NRC OPERATION TELEPHONE NUMBER: PRIMARY -- qr SOD3-3469 , P -- t301-81B-b1 stIjU W- 05I-u0 or 8U0-49-3.4 ,1,'nuj 301-4115-0550 and [3rdl 301-415-0553 'LIloensees wnc maintain their own ET'S are provided these taleohone number.

NOTIFICATION TIME FACILITY OR ORGANIZATION UNIT NAME OF CALLER CALL BACK #

Dominion - North Anna - "0 2

. 05 Power Station 1 and 2 Tom Shaub (804) 273-2763 EVENT TIME &ZONE EVENT DATE POW ER/MODE BEFORE POWER/MODE AFTER 0

N/A i 07/26107 100 /d/Mode 1 100%/Mode 1 EVENT CLASSIFICATIONS 1-Hr. Non-Erm*egency 10 (LFR50.72(b)(1) (V)(A) Safe S&D Capability AINA GENEIAL EMERGENCY GENIAAEC T evation (V)(B) RHR Capability AINB" SITE AREA EMERGENCY SLT/AAEC 4-Hr. Non-Emergency 10 qFR 60.72(b)(2) (v(C) Control ct Red Release AINO ALEFt ALEAAEC (I), TS Required SID ASHU (v)(D) Accident Mitigetion AIND U AL EVENT

=NUS UNU/AAEC (Iv)(A) ECCS Discharge to R , ACCS (xii) Offslte Medical AMED NION-EMERGENCY WiO.72 (sc ehunw* (iv)(B) RPS Actuation (scraH) ARPS (xJii) Loss cf Comrm/Arrt/Resp ACCM PHYSICAL SECURITY (73.711 DDDD (xt) Of..*.e Notification APRE 60-day Optional 10 CFR 5073(a)(1) 10ATENIALEXPOSURE B??? 8-Hr. Nom-Emergency 10 l FR 50.72(b)(3) Invalid Specified System Actuation FITNESS FOR DUTY HFIT (i0)(A) Degraded Condition ADEG Other Unspecified Requirement (Identify)

X OTHER UNSPECIFIED REQMT(aaIa ii)(B) Unanalyzed Conditlor Cr. AUNA 10 CFR Part 21 Notilication NONR INFORMATION ONLY NINF (Vv)(A) Specified System Aoi'aton AESF NONR DES($RIPTION Include: System tfected, actuations and their mnitlating signals, causes, erl¶t of event on plant, actions taken or planned, etc. (Continued on back) 10 CFR 21 Notification Internal cell resistance measurements obtained on one of the 4 fety-related emt ergency diesel generator (EDG) batteries identified a possibly degraded cell. The affected cell was replaced and ubsequent destr uctive testing revealed significant corrosion within the battery.

Component Information (as applicable):

Manufacturer: Enersys (Exide)

NSSS/A-Model Number 7(

Part Number: -CA-5 Doscrip~tion: I In 2005, Internal Operating Experience from Dominion Substat on Engineering communicated a potential long-term degradation issue associated with Exide model 3CC-7 batteries. The degr' tation is the result of an improperly made connection during the manufacturing process at Exide's (Enersys) facility in SumterI;C, during the mid to late 1990's. There are no batteries of this specific model at North Anna, however, the commercially ded, ated batteries (Exide model 3CA-5) for the EDGs are of a similar design and were manufactured at the same facility using the me process.

The jars susceptible to this process have a serial number beg ning with "05", indicating they were manufactured in the Sumter facility. There are no visual inspections that can definitively del -rmine if any of these batteries are exhibiting premature degradation. However, susceptible cells may be detected by ri easuring the cell internal impedance, resistance, or conductance.

On March 24, 2005, cell internal resistance readings were ob I.ined on one of the EDG battery banks using an Alber cell-corder.

Out of sixty (60) cells, three (3) exceeded the overall average for the battery string and on a fourth cell no reading could be obtained, indicating a degraded cell. The affected cell was re 4aced and subsequent destructive testing revealed significant corrosion at the positive post.

Continued on next page NOTIFICATIONS YES NO WILL BE ANYTHING UNUSUAL OR ,

NOT UNDERSTOOD? YES fExolain above) X NO NRC RESIDENT x DID ALL SYSTEMS FUNCTION AS REQUIRED'I " X YES NO (Explain above)

P- STA-TE(o)

LOCAL X X MODE NINIL OF OPERATION C;ORFRECTED'. ESTIMATED RESTARTDATE:

ADDIT1ONAL INFO ON BACK.

X YES NC OHRGoV AGwNCI-eS X Mode 1 N/A MENRCPPEFRM 361I (1-20 ,RITE O RCYLE PPE NIFIC FORM 361 (12-200) PRINTED ON RECYCLED PAPER

2 8042733715 p.

Jul 27 2007 8:30 DOMINION ADDRMIOI*. INFORMATION PAGE 2 OF 2 n *Niv-,i V%#5I~fI n, tae~ e.ur.,, nc ,, , em&unw man, WCIA~ .'fffj.Jflf. .4a4.o~IuIaynInfl*hinnc aIn,,tM hn t.nup.r.,4 In auant ulner.rinflnnl LIQUID RELEASE GASEOUS RELEASE UNPLANNED RELEAS PLANNED RELEASE ONGOING TERMINATED MONITORED UNMONITORED OFFSITE RELEASE T. S. EXCEEDE_ RM ALARMS AREAS EVACUATED PERSON NEL EXPOSED OR CONTAMINATED OFFSITE PROTECTIYE ACTIONS RECOMMENDED 'State release path Indescription Total Activity (CIO% Release Rate (Cliaec)  % T. S. LIMIT o00 Total Activity (CI)  %/T. S. LIMIT HOO GUIDE Noble Gas 6,,__Cl/sec 1000 Ci Iodine ___ uCuse_ 0.01 Ci Fprtlculate __ fiCilsec 1 mCi Liqulid(exGi*WJU Irllum, nd T uCimJ 0.1 C5 Liquid (tritium) ,,,_0__ _ _ CumIn 5 Ci Total Activity PLANT STACK CON;EISER/NR EE, R MIN STEAM LINE

• BLOWDOWN OTHER RAD MONTrR READIN*S ALARM 5ETPoINTS

% T. S. LIMIlT p( iiab Jo)

RCS OR SO TUIBE LEAKS: CHECK OR FILL IN APPLICABLE ITEMS: fapofflo detal&VewxP +Ions should be covered Anem'ant dew.rW in)

LOCATION OF THE LEAK (e.g., SG #, valve, pipe, ere-)

LEAK RATE: UNITS gpnvgpd T. S. LIMITS[ SUDDEN OR LONG-TERM DEVELOPMENT LEAK START DATE TIME COOLANT AOTIVITY PRtMARY SECONDARY AND UNITj:

LIST OF SAFETY RELATED EQUIPMENT NOT OPERATIONAL EVENT DESCRIPT!d (Continuedfom front)

IJ D erlbtio (continued)

A Part 2i evaluation was performed (2005) and it was conciudce:i that this was not a substantial safety hazard because the defect would be identified through normal battery testing befor4 a battery was rendered incapable of performing its function. A more recent review of this issue along with discussions with N personnel has resulted in re-evaluation of this earlier conclusion. Without the new quarterly internal cell resistance tI, ts that were created, the Technical Specification required battery surveillances (weekly, quarterly and 18-month) would n t be able to detect this internal degradation. The 5-year EDG battery capacity test would be able to detect when internal resi ance advanced to the point where capacity was <800% of manufacturers rating, but the degradation could progress betw, n tests resulting in inoperability without detection.

Cajuses:

Equipment Specification, Manufacture, and Construction- Fabri tion Deficiency The internal lead post and connector/ terminal within the battei, jar were bonded together by hand using a high temperature heating process referred to as a "burn". If the temperature usec Juring the "burn" is too low, cracks and voids are left between the post and connector. Acid seeps into the voids, causing the ýost to corrode and resulting in an open circuit over an extended period of time.

CQorrective Actions Cell internal resistance readings were obtained on all four (4) b! tery banks for the EDGs. There was one cell for which no reading could be obtained and was replaced immediately. A secpnd cell had a reading that was nearly four times the average of the associated string and was subsequently replaced as a proa tive measure during the EDO maintenance outage. Three (3) other cells were noted with higher than average readings that ai not considered to be operability concerns. In total, five (5) cells out of a total of 240 were found with higher than expected interl``a resistance values.

Periodic testing of all North Anna EDG batteries was put in piac( to monitor for this defect (increases in internal cell resistance readings) to confirm continued operability of all EDG batteries. i 1 parallel, plans were launched to replace all EDG batteries with models that are not susceptible to this defect. Unit 2 batteries have been replaced and Unit I batteries will be replaced during the fall 2007 outage.

NRC FORM 361 (12-200) PRINTED ON RECYCLED PAPER