ML20236G823

Forwards Response to 870910 Request for Addl Info Re Changes to Station Batteries Reflected in Tech Spec Change 137.Ltr Also Documents Conference Call W/Nrc on 871015.Requests NRC Reevaluate Previous Submittal & Approve Tech Spec Changes

ML20236G823
Person / Time
Site:	Beaver Valley
Issue date:	10/26/1987
From:	Sieber J DUQUESNE LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
TAC-65781, NUDOCS 8711030292
Download: ML20236G823 (12)

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Telephone (412) 393-6000 11 Nuclear Group

. P.O. Box 4 Shippingport, PA 15077-0004 x

October 26, 1987 l

i

'U.

S. Nuclear Regulatory Commission Attn:

Document Control Desk

.kWashington', DC 20555-s

Reference:

Beaver Valley Power Station, Unit:No. 'l Docket No. 50-334, License No. DPR-66 Additional Information

' TAC Item 65781 Gentlemen:

a 1

This letter -provides our response to your request'for additional-l l

information dated September 10, 1987 concerning changes to the-I station batteries reflected in our request for; Technical i

L Specification Change No. 137.

l This letter also' documents'a conference' call'between'NRC and DLC 1

l staff members on October'15, 1987.

DLC staff stated that all of the

]

lead-antimony alloy batteries have been' replaced with, lead calcium.

l alloy. batteries.

Station. Batteries 1-1 and 1-2 are 60' cell lead.

calcium' alloy batteries -manufactured by ;Exide Corporation and l

batteries 1-3 and 1-4 are 59 cell lead-calcium -alloy batteries l

l manufactured by C&D Power Systems.

The proposed changes to' reduce the Table 3.8-1 specific gravity l

values are based on the results of an' evaluation of' battery. operating i

data.

.The results indicate that the' station batteries.are being 1

placed on an equalizing charge, due to low specific gravity readings, l

much more often than recommended by the manufacturer.

This raised 1

the concern that the. expected battery life'is being unnecessarily j

reduced and other DC components which see the higher DC voltage when j

the ' batteries are being charged are being degraded'on an: accelerated' a

basis due'to the deleterious effects of the frequent equalization, i

j The revisions in the propose'd technical specification' change were l

developed from recommendations of both battery manufacturers. to minimize plate deterioration-and achieve optimum battery life.: -The J

attachments document the.information-exchange between the' battery >

f manufacturers and DLC.

Attachment 1 provides a discussionof the.

Table

'3.8-1 specific. gravity revisions. by ' G.' -

Walker (C&D' Power) l Systems).

He', iterated 'that the STS values were' acceptable forLthe:

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l lead-antimony.

alloy batteries, however,.'due to. the different-I charge / discharge

'and float voltage' characteristics of

-the a

8711030292 871026

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PDR ADOCK 05000334<

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Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 Additional Information - TAC Item 65781 Page 2 lead-calcium battery it is recommended that lower specific gravity limitations be applied.

He also provides a reference for additional information that can be found in Appendix A, Sections Al and A4 and Appendix B

of IEEE-450 1980.

The manufacturer states that even at the less stringent limitation of 1.195 the battery capacity discharge capabilities will only be reduced by 4 to 5%.

This can also be seen in Figure 1

that was provided with the proposed technical specification

change, at a specific gravity of 1.210 the battery is capable of 100% of its available capacity.

At a specific gravity of 1.195 it can be seen that the battery is capable of 95% of its available capacity.

If we reduce the UFSAR Table 8.5-4 design margins for each battery by 5%

to take into account the lower specific

gravity, the design margins available for individual batteries 1,

2, 3

and 4 are respectively:

10%, 15%, 75% and 210%.

Then even Battery No. 1 will still have a minimum 10% design margin available in addition to the 19% available for temperature affects and 24%

available to account for aging affects.

On this basis, the batteries will have more than adequate capacity to supply the required loads throughout the battery lifetime including temperature and aging affects.

Therefore, the proposed change will have no impact on safety since the required battery capacity, even with the lower specific

gravity, will be available to supply the accident analysis loads.

Attachment 2

provides documentation of a request from DLC (Memorandum John F.

Ankney to Bob Blohm) for the Exide battery manufacturer to review the proposed Table 3.8-1 revisions and concur with the change if applicable.

The Exide response (C. N.

Reichart) is also attached.

The proposed change to Table 3.8-1 where

" Float Voltage" is replaced with

" Cell Voltage (Battery on Float Charge)" provides clarification of the parameter description since- " Cell Voltage" describes the parameter to be verified and has a limit of 2.13 volts consistent with surveillance requirement 4.8.2.3.2.a.2.

" Float Voltage" is an incorrect term to identify this parameter since the float voltage for these batteries is 2.25 volts.

We feel that if the incorrect descriptive term is used for this parameter, then the potential exists for procedure error which could have a significant impact on the safety of the plant.

Therefore, even though this descriptive term is different than specified in the Standard Technical Specifications,

" Cell Voltage (Battery on Float Charge)"

more correctly identifies the subject parameter and will reduce the potential for procedure errors and will not impact the safety of the plant.

Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 l

Additional Information - TAC Item 65781 i

Page 3 Based on the above, the proposed changes provide clarification, reflect the battery manufacturers recommendations to minimize plate deterioration and achieve optimum battery life and do not impact the safety of the plant.

Therefore, it is requested that the NRC re-evaluate our previous submittal and approve the proposed technical specification changes.

Very truly yours,

. D.

Sieber ice President, Nuclear cc:

Mr. F.

I. Young, Sr. Resident Inspector (Unit 1)

Mr.

J.

Beall, Sr. Resident Inspector (Unit 2)

Mr. W. T. Russell, NRC Region I Administrator Mr. P. Tam, Project Manager Director, Safety Evaluation & Control (VEPCO) i I

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}E f 1 Our recommendations for lowering the specific gravity limitations of your current Battery Surveillance Requirements Udla.

.i d.S.1.1.0-1.n0 0.0.0. M ).to those. values shown inithe revised' I

procedures are explained below.

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I Whereas the original limitations may be acceptshle ior Lead Acid

.e satteries with antimony alloyed plates, because"its characteristics and charg!.ng requirements; tend;to hasten-i dif fusion of the electeslyte solution,- such' is not the case with

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1ead acid batteries of calcina alloy construction.

i float within a voltage range selected by.~the manufactyeet:to 'Both; types provide a current necessary toikeep'the_ positive platsi 50 to 1001r 3

millivcits above.open circuit potentisi.-.At this - potentiel'..

Plate deterioration is minimized 3and optimum life isLachtsved.

The lead calcium battery, even though-its recommended tloat.. / '

voltage is 0.05 to 0.10. volts per cell _ higher than a n'v lead antimony battray, will require 3 to 6 times less chargimg current e

to maintain the float voltage. 'At equalising voltage of 2 33 volta penmthe commonly accepteidf s

requires 10 times less current.than a new lead antimony-bstturysnit, a lead of identical capacity.

Since.the amount.of overcharge current determines the rate at which hydrogen and oxygen =are. formed w

(g&ssing)-- and~the greater the gassing _ rate, the greater'the mixing action that occurs.in'.the electrolyte as bubbles-break free from the. surface of.the platse.end' rise to the surface--

ttierelsetrolyte-invthex3eyd esietua~ no11*e11Ptef4WWCTWoo esttatyd*by gus=bubb2ed?'than arited istiWisy7e4D 11

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II N3 y Partester Ltof ts forhch limits for each AllowableII)

$k designatad pilot connected tell value.for each gUs cell eennected cell.

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Electrolyte

> Minimum level

>Minfeue level ~

Above top of-7 Level indication mark, indication mark, plates.

01g and < V' above

-and<%"above and not foi 2

samtEumlevel namiEum level overflowing

1. y indication mark Indication park

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> N volts float Vohese 12.13 volts 1 2.U volts n

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(a Corrected for efettvwlyte temperature and ley F

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Cebatterychargingcurrentislessthandyempswhenench'arge,

. Corrected for average electrolyte temperature.

For any Category A prameter(s) outside the limit (s) shown the battery l

may;';e considered OPERABLE provided that within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> all the Category 8 l

measurements are taken and found to be within their ellowable values, and b"

provided all Category A and I paraseter(s) are restored to withfii limits L

within'the neitt 5 days.

J (2) For any Category 8 parameter (s) outside the limit (s) shown the battery may be considered CPERA3LE provided that the category 8 par,ameters are-within their allowable values and provided the category 5 parameter (s) are redored te within limits within 7 d4ys.

(3)'Ans Category 8 parameter not within its e1 Towable value indicates an inoperable Batter /.

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In fact, in extreme cases.-(such as a prolonged low float voltage condition,. er a deep discharge - followed by acrecharge' at. minimum float voltage U a' apecific gravity gradienti'willE come to exist.

In this,conditionT"the electrolyte specific gravi.ty'will-be i

higher?than nominal at the; bottom of-the'pistes and lower than-nominal at the top.

CellsLin this condition Mee stilltableJto l

deliver power, however, depending onithejse crity of the gradient

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.and length of time ; lye condition esiatr y bar'eries'may not be

< capable:of.meetin>3' design capacities cr;11fe.

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Additional information'can be found in the Appendixes!of

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IEEE-450-1980, specifica11y' Appendix.A, Sections'A1 ard'A4, and 1

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Now then.your origina.l pilot cell. limitation (Category A) waf.

i 1.200 Sp.Gr. 477'F,-with the electrolyte leveliabovm-the nifilimum; y'

indication. 'Since 1.200 8p.Gr. is within manufac'turers' I J W

tolerances, and because an electrolyte:1evel b inch above'the high level indicator would -presuppose / an overwatered condi'ti on--

. / l.j with a subsiquent. reduction in elegtrelyte specific gravity--#

cell with this specific gravity w#had not require 1 corrective.

' action to insure operability.

Our'less stringentirecommended limitation of 1.195 Sp.Gr. sti71 providea en' adequate safetyJ b

margin because if the pilot cell is 1.195," everage specific gravity throughout the.

that particular cell will-have'had its discharge capabilities reduesd only,4'or Sg from its, nomina 11 1

'.210 or 1.215 sp.Gr. rates.

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ff[#CNR$f / a$ l since this.is only one call eat of-many, and because the battery is eversized to compensate for minimum temperature and aging losses (and say even be performing at greater than 1002 of its. ratings), a maall capacity loss in one cell will not ser,fously tapact the overall bettery perforssace. The.same rationale applies i to our recommended limiting values for ) Category 5. Assuming so specific gravity gradient and the everage of all connected cells is 1 1.195..for whatever battery internal problem--the battery will atill be capable of-re well over 901 of its design rating. Sising calculation would i then show how much still exista, or the amount the aging margin is reduced. At any rate, considering a. battery anoperable at specific gravities greater than 1.195 is overly stringent, would be justified only if the battery performance and/or service and test show the battery to have little or no design margin. l On a somewhat related topic, I suspect your Surveillance / Maintenance Standard might set a maximum. cell connection resistance of 150 microhma. This is acceptable for battery which is not .<hI A currents, however, required to provide high / c o n s i d e r e d., we receasend a maximum of 50 microbes be i Some final words about measuring specific gravity. Our Installation and Operating Instructions, Publication No section VII paragraphs J2-800, 7.7 and'7.11 provides information for i correcting the electrolyte specific gravity with respect level. e This is not to its recommended for your surveillance program since the values are not absolute, but electrolyte level.to cell model depending on electrolyte volume andwill vary from initial Thus, to be of any use, you would have substantiate that all cells to (s) there is no specific gravity gradient,are fully charged. (b) substantiate and (c) have' records indicating the exact specific gravity levels for all cells as received and initially charged, plus records of all subsiquent water additions. Since, under moraal float i it will take several years operating conditions, cause the electrolyte level for evaporation.and electrolysis to to drop one inch in the lead calcium cell, the.information should not be used to determice bettery operability. I trust this is clear and concise. give ne a call. If you have any questions, Very truly yours, hgghl=4.kw Graham Walker

hanager, Applications Engineering L

bec: V. Kopf J. Carroll W. Brecht l l

i //~ C /bW ' j s i 1 i l 1 i s 1 1 1 ')JG Jh.M4h It(4tTT (.o. 3whn? Ms hatrt.64T.e4 Omvi i s.9p g a r, R W.hM.% W-Gentlemen: 1 The battery charger output current curve shotos below should be self explar.atory and is applicable for any lead calcium battery in any state of discharge. i i .._....n ..t._........ ._ g g gg,, _ _.... t...

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i _ _.._._.=i....... 4 4 ...i. M............. POItfr AT W!iICH BATTERY CAN BB CONSIDERED CAPABLI? .............a. ...n -. " ;- a. :: ... :.. :n..n. n-.

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.n. _: :n..u.::. OF MEETING PERFORMANCE .t._._._ .............. = .t......... _.. - .._......w_... ... 1 g O TIME==-Wp If you have any guestions, please do not hesitate to contact us. Very truly yours, .m Eltta company Saha *1*r contract Administrator

Duquesne Udit Company C/-/M/&#/ R FORM D23106153 Bob Blokm "V o A n F, an.knev TO: LOCATION;

1. MAIL OROP:

TO; DATE; /7 -/ 5 SI. C Circulate Q Retum QFile

SUBJECT:

Tee k SPe e-CL a ys fat t Cd N ~ 2 \\ B r++* HI* 3 MESSAGE: #+heLed is a m.a c ked eeou of Tec.L. J oec. I ! Sq tle 3,7-l. TLo n ew m r xed v at ue.s of e,oecibe o rsvi+v ai a areed +s w e'+L b a+1eru ve n of o r - J r J t C4D Po ua r 6v.s f e m J a r e s L. e w a.' Du c u. 4 n.o L?a L+ b_e moa a v'.mL of I tKe fe moti%c.)+ e xo r!tk.soe?e.TLble C r atI -Foar &. s v-I ~ h r+ +e to se+.s > f ker efate. we w s u.I d I l4 ~ g w 1+L <flo so.I u e e a s. ~ a rWed, uauv esnearyexee io+e +bt +ke e i d 4 e c(.s o u, v d u. s o e re fo r ~ l lead a d k a n.v s ad 1-G kass ceils are le ad I caleium wL b are < J, e cf fo sfraf,Mht eh. ~ 4 .\\ 1-f a s u sseee t-o +Le el.anae s. en u t J WP[lT9 Q W / 4 A t'o A e c/ m3rd cdaYeN pg cY e Ye Y a c4 No e-f[e cY ie M.y CLY i8 h.il e/1 I- "Tkata.M Watt naene s n e LM+ Ca. R ESPONSE: V Na clear Do'v ha'e a P. e. E n n. I S M oo t a. o.e.f.Pa.>ro77 II ,Ji I Affn.' John F. AnKney ( r/, w z.39 3 ro FF )

~ }}77fCfff/E/Vf~?2 ~ . TAB LE. 3. 3-IL .) , ).' BATTERY SURVE*LLANCE REQUIREMENTS a Cl) CATEGORY B(2) CATEGORY.A A11cwable$3) Parameter Limits for each Limits for each designated pilot' c:nnected call. value forfeach-call c:nnected call' El ectrolyta >Minimur:r-levei > Minimum levei LAbeve t p of . Level indicati:n mark, indication mark, pl.atas, - and < h": accve and <-h" abovel .and not maxiEum level maxiEum: level. overflowing _ indication mark indication marki ~ ~ .1 Fica: Vci tage > 2.13 volts

> 2;13 volts (C)-

> 2.07 -volts ' Not zers-taan .020 below: the le ITO' average of-all- , 1 '*. S~ connect.ad calls Scecifi58) >1.2gb) Gravity j, / 9g-Average.of.all' Average of'all connee ed calls c:nnectg) calls > 4M/, ?_o o >W /. / 9 0 (a) Corrected for electrolyte temperature and level; i (b) Or battery charging current is less than:(2) amps when on charge. 1 (c) Corrected for average electrolyte; temperature... (1) For any Catager/ A parameter (s) outside the limit (s) shown, the battarj_ may be considered OPERABLE provided that within 24 hcurs all'the Categorf 2 measurements are taken and found to be within their allowable values, and: l previced all Catager/ A and 3 parameter (s) are restored 'to within limits. I within the next 6 days. (2) For any Catagery B carameter(s)'outside.the limit (s)l shown, the.battar!: may ce censicered OPERAELE provided that the Category S parametars art = within'their alicwable values and provided-the Catagery S. parametar(s)lare j restorec to within limits within 7 days. L (3) Any Catac:rj S parameter not within its allowabie value indicatas an inepersoIe battarj. INsm:e s in :arttheses assame a manufacturer's rsc:=ar.cac fulf charga i :ecific ;ravity of L 215. s ) 3/ A 3- ?* Amendment No. 54 Iwtn wu.n - n - t

r-, \\. ' 1 .3 0 3.- 1 7 1 1 Y 7 + Y r 7 ^ / M:morandum IACO ElectioEnergy Z% -,. - RAYoVAc UNmeasAL SECMC

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