ML20043B501

Application for Amend to License NPF-6,revising Tech Spec 3/4.8.2 Re Voltage Correction for Average Electrolyte Temp in Station Batteries & Clarifying That Equalizing Charge Based Simply on Actual Cell Voltage Measurements

ML20043B501
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/22/1990
From:	Carns N ARKANSAS POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20043B502	List: ML20043B501 ML20043B503
References
2CAN059003, NUDOCS 9005300111
Download: ML20043B501 (4)

Text

i Arkansas P;wer & Upht Company

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May 22, 1990 L

2CAN059003 i

l U. S. Nuclear Regulatory Commission E Document Control Desk Mail Station P1-137 Washington, DC 20555

Subject:

Arkansas Nuclear One - Unit 2 Docket No. 50-368 License No. NPF-6 Revision to Battery Technical Specification Change Request Gentlemen:

Arkansas Power and Light Company (AP&L) submitted proposed changes to ANO-2 i Technical Specification (TS) 3/4.8.2, involving the station batteries, by letter dated August 23, 1989 (2CAN088904). One of the changes proposed was a ,

revision of Note-(c) of Table 4.8-2, regarding voltage correction for average .

electrolytc' temperature. Our submittal proposed to reflect the voltage '

correction allowed by 1EEE Standard 450-1980 Appendix C, which recognizes that

'the voltage of warmer battery cells will be lower than the battery average. ,

~fhe battery cell voltage after correction for temperature is used to determine if an equalizing charge is necessary. This decision is presently based on calculated temperature values determined by the complicated series of: .'

neccurements of cell temperature, determination of average temperature determination of ttmperature deviations, and then determination of whether  ;

an equalizing charge is necessary. During conversations witn the NRC staf f  !

subsequent to the previously referenced submittal, it was determined that eliminating this existing complicated process of calculating adjusted cell '

voltages by deletion of the temperature-based voltage adjustment (i.e., deletion '

of Note (c) of Table 4.8-2) would be acceptable with sufficient justification.

AP&L therefore proposes to modify Table 4.8-2 such that the decision to apply an equalizing charge is based simply on actual cell voltage measurements.

The purpose of this letter is to provide the following justification and the associated revised TS pages. x

$ IEEE 450-1980 Appendix C.3 allows increasing the measured cell voltage by a '

factor of 0.003 volts per *F that the cell temperature is above the average temperature of the other cells. Although the correction is not specifically addressed by Appendix C 3 for lower cell temperatures, the NRC staff reviewer has applied the interpretation to this temperature correction factor for both directions, thus rer.; ring a battery cell with a lower measured temperature to ,

be adjusted downward due to its higher indicated voltage, and a cell having a higher measured temperature to be adjusted upward to account for its lower -

indicated voltage, consistent with existing ANO-2 TS requirement of Note (c).

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, Page 2 i May 22, 1990 p l F .To. address AP&L's objective of not requiring complicated calculations when I

individual cell temperatures deviate from the average, and the NRC staff reviewer's concern of only correcting for cells with warmer than average  ;

temperatures, it was agreed to delete Note (c) with sufficient justification. j The ANO-2 battery float voltage (approximately 2.20 volts per cell) is higher I than the TS Table 4.8-2 minimum of 2.13 volts. Consequently, before the adjusted voltage could approach.2.13 volts due to temperature alone, cell temperature would have to be more than 20'F below the average. Likewise, at 1 the Table 4.8-2 Category B Limit value of 2.13 volts, a 20*F deviation from the average temperature must exist prior to approaching the 2.07 voit Allowable Value. As discussed in IEEE 450-1980 Appendix D.3, large cell temperature 4 deviations (higher than average) are usually caused by shorting conditions,  ;

which are also evident by the cell voltage, and indicate the need for immediate cell replacement. Other temperature deviations are usually caused by outside l

< conditions. Such temperature gradients have a low probability of occurrence 3 at ANO, because of the close proximity of the cells and the controlled '

environment which exists in the station battery rooms, t

Examples can be postulated where the existing TS would require cell voltage adjustment and not require an equalize charge, but where the proposed TS (with the temperature-based voltage adjustment deleted) would indicate the need for an equalize charge

• or, where a decision to equalize charge would be a forced o actionunderastrletTSinterpretationiftheexistingNote(c)wasretained, but not indicated if Note (c) was deleted. The latter situation would involve a colder than average cell measuring above the TS Category B Limits; applying the temperature-based voltage adjustment referenced above may bring the individual cell voltage below the 2.13. volt TS Limit. However, we are unaware of any credible scenarios which would rasult in a hattery cell being Significantly colder than the battery average. Further, the decision to be made by cel? voltage mersurement is whether to perform corrective action (nbrmally an equalizo charge), not to determine battery operability. Without cors'oericg the tempe>ature gradient, such decisionr> would be made simply on direct toltage rieasurements rather than theoretical calculated values.

For the reasons discussed above, deletion of the tempercture-based battery cell voltage correction will not adversely impact the decision making process

-regarding corrective actions required by TS 3/4.8.2. The battery surveillance process would be greatly simplified, the potential for mathematical errors would be reduced and corrective action decisions would be based upon direct voltage measurement versus calculated values.

AP&L'therefore proposes to revise our August 23, 1989, TS change request by.

submitting the new proposed TS pages 3/4 8-9a and B 3/4 8-2. On the attached pago 3/4 8-9a, Table 4.8-2 Note (c) has been deleted; Note (d) has been redesignated as Note (c); the wording for Category B Specific Gravity Limits and Allowable Values have.been clarified. On page B 3/4 8-2, the last paragraph has been deleted. The proposed changes on TS pages 3/4 8-8, 3/4 8-10, and B3/4 8-1 proposed in our August 1989 rcquest are still required as previously

- subtai tted.

r-~~~v 49 U. S. NRC Page 3 May 22, 1990 l.:

i; i Sincerely,

, f= = ~ ,

NSC/rbt Attachments cc: Mr. Robert Martin l

U. S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 -

NRC Senior Resident Inspector Arkansas Nuclear One - ANO-1 & 2 Number 1, Nuclear Plant Road Russellville, AR 72801 Mr. Thomas W. Alexion NRR Project Manager, Region IV/ANO-1 U. S. Nuclear Regulatory Commission NRR Mail Stop 13-D-18 One White flint North 11555 Rockville Pike Rockville, Maryland 20052 ,

Mr. Chester Poslusny NRR Project Manager, Region IV/AND-2 U. S. Nuclear Regulatory Commission NRR Mail Stop 13-D-18 One White Flint North

• 11555 f.ockv111e Pike Rockville, Maryland 20852

i-4 ..

STATE OF ARKAN$AS )

i

) SS COUNTY OF POPE )

I, N. S. Carns, being duly sworn, subscribe to and say that I am Vice President, Nuclear for Arkansas Power & Light Company; that I have full authority to execute this oath; that I have read the document numbered t

2CAN059003 and know the contents thereof; and that to the best of my

[ knowledge, information and belief the statements in it are true.

D]lbs: -

N. S. Carns SUBSCRIBED AND SWORN T0 before me, a Notary Public in and for the County and State above named, this _ M day of Y//an _ ,

i d 1990, tr L nn Nothry Public My Commission Expires:

5 4-91