ML19329B085

LER 78-013/03L-0:780119,Cell 32 in Station Battery 1N Electrolyte Specific Gravity Decreased 0.003 Greater than Allowed by Tech Spec 3.8.2.3.Caused by Electrolyte Stratification Due to Low Battery Loading

ML19329B085
Person / Time
Site:	Davis Besse
Issue date:	02/15/1978
From:	Beeler T TOLEDO EDISON CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III)
Shared Package
ML19329B086	List: ML19329B085
References
LER-78-013-03L, LER-78-13-3L, NUDOCS 8001300675
Download: ML19329B085 (3)

Text

U. S. NUCLEA H H ut.a u tm u rs i w.. ... o.w.

RC FORM 366 p.ny J

- - ~' LICENSEE EVENT REPORT .s h

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74 .s a E= cst o ATE m3 a 60 si OcCxET NumeER EVENT OESCRIPTION AND PROB ABLE CONSECUENCES h .003 greater charj a#2l l Cell 32 in Station Battery 1N electrolyte specific graviev decreased 9,3, g a. lowed in Technical Specification 3.8.2.3. This placed the unit in the Action State-i direct cur- I g ,3 , .i j l ment of Technical Specification 3.8.2.3 which requires all four 125 volt There was no danger to thel j,,3j  ; rent battery banks to be operable in Modes 1, 2, 3, and 4.

to tal I health and safety of the public or unit personnel.

Only one cell had an accarent  !

l o } 71 l slight decrease in specific gravity. The average electrolyte specific' gravity for thel

! cell is expected to have been within tolerances. (NP-33-78-14) 30 I

,3,3, COMP. VALVE SYST EM CAUSE CAU35 COMPONENT CCOE SUSCCOE SUSCCCE CODE COOE SUGCCOE le191 1 El c]g l xi@ I z l@ f3l si Al TI Ti alyt@ l:1@ lzl@

12 18 13 20 S 9 10 11 REVIS10N SEcuEN TI AL CCCURRENCE RE*CRT C00E TYPE N O.

EV ENT Y EAR " REPCRT No.

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,,,, 21 22 23 24 26 27 ATTACM.ENT NPRo-4 PRIME CO*AP. COMPONENT TtON FUTURE EF8ECr SHUTOOWN SUBMITTED FORM WB. SUPPLIER MANUFACTURER oN PLANT METHCo HOURS TAKEN ACTION I33 E!@lHl@ Izl@ i;6z l@ 1 81010 I lY l@

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44 41 34 OS 37 40 CAUSE OESCRIPTION AND CORRECTIVE ACTIONS h

) i { o l l The low specific gravity has been attributed to electrolyte stratification due to low

,,,,; gbattery loading. Under Maintenance Work Order 78-182, a single cell char 2er was used l

,,y to increase the specific gravity. To prevent recurrence when electrolyte stratifica- l the electrolyte will be cycled to provide I

, , , , g g tion is expected in a station battery,

,,,,, ,a representative sartple. so

' ISCO BY OISCOVERY DESCRtPTION

'. POWER oTHER STATUS ST ST 5084.03 l i t s l l z l@ l0 l 7 l 5 g,j NA l lBlglSurveillanceTest 30 l

to 12 13 44 45 46 7 4 3 ,

ACTIVITY CON TENT 4 LOCATION CF RELEASE -

A" CUNT CF ACTIVITY

1. ELE ASED '37aELi43E l I *^ l liIcl 3LzJ 7 9 G Iz !O l "^

10 11 44 45 30 l PERSONNEL EXPOSURES l

NU ' ER TY86 CESCRIPTION l1hIl 80

' PERSCNNEL tNJURIES Nt;oogg OESCRIPTICN I

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LOSS OF OR DAMAGE TO FACILITY 4 Tv8E DESCmPTION NA 40013 O[ w l l

11 : 01 I z i@l10 83 7 8 9 NRC USE ONLY PUBLICtTY  ?, I rer mFICN #6

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-JELEkd)Mk .' a - .>. Tom Beeler MM3~ ( ' 19 ) 259-5000, Ext. 2537

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TOLEDO EDISON COMPANY

(' 's I DAVIS-Bu

• UNIT OME NUCLEAR POWER STATION SUPPLEMENTAL .NFORMATION FOR LER NP-33-78-14 DATE OF EVENT: January 19, i978 ,

FACILITY: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE: Low specific gravity for Station Battery IN, Cell 32 Conditions Prior to Occurrence: The unit was in Mode 1, with Power (MWT) = 2071, and Load (MWE) = 710.

Description of Occurrence! At 0830 hours0.00961 days <br />0.231 hours <br />0.00137 weeks <br />3.15815e-4 months <br /> on January 19, 1978, while reviewing the

" Quarterly Battery Surveillance Test" (ST 5084.03) data, a Maintenance Foreman discovered that Cell 32 in Station Battery 1N failed to meet the acceptance cri-teria of the Surveillance Test. The cell specific gravity had decreased 0.013 since the previous quarterly test which is a specific gravity decrease of .003 greater than allowed in Technical Specification 3.8.2.3. This placed the unit in the Action Statement of Technical Specification 3.8.2.3 which requires that two (2) ps 250/125 volt Direct Current Motor Control Centers and four (4) 125 volt Direct

\ ) Current battery banks and chargers be energiaed and operable for Modes 1, 2, 3,

' and 4.

Designation of Aoparent Cause of Occurrence: The low specific gravity has been attributed to electrolyte stratification due to low battery loading. These bat-teries are not normally heavily loaded which allows the electrolyte to separate into layers (lighter electrolyte rises). The sample point for the Surveillance Test draws from the upper third of the battery. Even though before the sample is drawn from the battery, several hydrometer volumes are cycled, the battery electrolyte volume is too large to be adequately mixed by the hydrometer.

Analvsis of Occurrence: There was no danger to the health and safety of the public or to unit personnel. Only one cell tested at slightly low specific gravity. This would not prevent the batteries from meeting short term power requirements. Also, the average . electrolyte specific gravity for the cell is expected to have been within tolerances; only the test sample specific gravity was. 003 less than the allowable value.

Corrective Action: Under Maintenance Work Order 78-182, a single cell charger was used to increase the specific gravity. At 0930 hours0.0108 days <br />0.258 hours <br />0.00154 weeks <br />3.53865e-4 months <br /> on January 19, 1978, Station Battery IN was declared operable. This removed the unit from the Action Statement  :

s of Technical Specification 3.8.2.3. i s , To prevent recurrence, when electrolyte stratification is expected in a Station '

Battery, the electrolyte will be adequately cycled to provide a representative sample.  ;

- Failure Dets: - TTere Save been no previous reported occurrences of low- battery

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