ML20085L523
| ML20085L523 | |
| Person / Time | |
|---|---|
| Site: | Prairie Island  |
| Issue date: | 10/28/1991 |
| From: | Parker T NORTHERN STATES POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-GTECI-A-30, REF-GTECI-EL, TASK-A-30, TASK-OR GL-91-06, GL-91-6, NUDOCS 9111040201 | |
| Download: ML20085L523 (9) | |
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Northem States Power Company 414 N4citet Mali Minneagibt. Mwinebata %401 1W27 lelephone (012) 330 %00 October 28, 1991 Generic 1.etter 91 06 U S Nuclear Regulatory Commission Attn:
Docu: rent Control Desk Vashington, Oc 20$55 PRAIRIE ISlA!;D NUClf.AR GENLPAT!!;G PLANT Docket Nos. 50 282 Licetu;e Nos. LPR-42
$0 306 DPH 60 Response to NRC Generic Letter 91 06: Res.olution of Generic issun.,_A.JL "Adeauncy o f S oh t y - r e l a t tLDC Powe r S upplirjL" Our response to Generic Let t er 91-06 in attached.
if you have any quer.tloin related to our response Please contact s
}ht4.) s lt* sn Thomas M 'arker Manager Nuclear Support Services J
c: Regional Administrator Region 111, NRC Senior Resident inspector, NRC NRR Project Manager, NRC J E Silberg Attachments
- 1. Affidavit 2 Generic Letter 91-06 Response 1
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i UNITED STATl:S NUCilAR REGUlATOl(Y COMMIS$10N l
NORT)lERN STATES l'0WEli COMPANY PRAIRIE 151AND NUCl,hAR CENERAT1NG P! ANT DOCLET NO. 50.?82
$0 306 RESDI.UTION OF Cl:NERIC ISSUE A 30,
" ADEQUACY OF sal'ETY.RI: LATED DC POWPR SUPl" 1ES" Northern St at es Power Company, a Minnesota corporation, with this letter is submitting information requested by NRC Ceneric letter 91 06.
This letter contains no restricted or other defense information.
NORTilERN SJ TES P JER ;0MPANY 67_ _hb 2. ZG &$/-
Tiomas M Parker Manager, Nuclear Support. Servicen on this d (Alay of
__ /gff_bofore me a notary public in and for said County, personally appeared Thomas M Parker, Manager, Nuclear Support Services, and being first duly sworn acknowledged that he is aut hori:.ed t o execute thin document on behalf of Northern Statns Power Company. that he knows the contents thereof, and that to the best of his knowledge,.i nf o rma t l on, and hellel the statements made~1n it are true and that-it in not interposed for delay, 4
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kESTONSE TO NRC CENERIC LETTER 91 06 1.
Unit: hitirit._111anLXutler.r Cenentiinr P1onutnits-1 6 2 2.
a.
The number of independent redundant divisions of Class 1E or safety-related de power for this plant i s Lye r uttil.
b.
The number of funcilonal safety related divisions of de power necessary to at t ain saf e shut down ior this unit is Lyer_ unit.
3.
Does the control room at this unit have the [vllowing
- neparatc, independently annunciated alarms una indications for each division of de power?
a.
alarms 1.
Battcry disconnect or cireuit breaker open?
No.
Please see the attached diagrams (B20.9-1 and 15?O.9 2) for the Prairic Island Nuc1 car Generat ing Plant. DC systems. There is no disconnect or circuit breaker downst ream of the battery, The main f uses are downst ream of both the batt ery and the batt ery charger.
The fu s.e s are bolted in place Removal of the f u ro c r.
would rer. ult in a loss of the entire de t i. a i n.
2.
Bettery charger disconnect or circuit breaker open (both input ac and output dc)i Opening the ac input brenter vill cause a " f.a t t e ry Charger Fa11ute" alarm.
At present there is no alarm when the de output breaker is open.
Modification 91L310 is in progress to add this alarm.
3.
dc system grourd? Xu 4.
de bas undervoltage? Xey 5.
de bus overvoltage?
No.
Modification 91L310 is in progress to add this alarm.
6.
Ba t t ery charger f al.'ure?
Xt1 7.
Battery discharge?
No.
Modification 91L310 is in progrets to add this alarm.
b.
Indications l
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Attechetent 2 ocurer 28, 1991 Page 7 of $
1.
Battery float charge current
- No.
Modification 91L310 is in progress to add this indication.
2, Bat tcry circuit output current ?
No.
Modification 91L310 is in progress to add this indication.
3.
Battery discharge?
I i
No.
Modification 91h310 is in progress to add this indicatlon, i
4.
Bus voltaget
_No.
_ Modification 91L310 is in progress to add this indication.
c, Does the uns t have vritt en procedures for response to the above alarms and indications?
Yes, for the existing alarms.
The modification in progress will add or revise the procedures for the alarms and ludications being added, l
4.
Does this unit have indication of bypassed and inoperable status of circuit j
breakers or other devices that can be used to disconnect the battery and bat tery charger from its dc bus and the battery charger from its ac power source during maintenance or t estingt Yes, for the battery charger.
If the battery charger is separated from the ac power source due to its input circuit breaker being opened, or due to the ac maintenance
- witch being in the spare position, the " battery charger failure" alarm will he received in the control room.
3 I
If the battery charger output breaker is opened, or if the de maintet,ance switch is in the spare battery charger position, the "de undervoltat,e" alarm will-he received in the control room.
No,-for.the battery, please see the attached diagrams (B20.91 and B20,9 2) i for the prairie-Island Nuclear Generating plant DC systemn, There is no disconnect or circuit breaker downstream of the hattery.
l l
The main fuses are downstream of both the battery and the battery charger.
The fuses are_ bolted in place. Removal of the fuses would result in a loss L
of the entire de train.
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F 3
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A t t ac hnent 2 (k toter i8,1991 Page 3 of h 5.
if the answer t o any part vi question 3 or 4 is no, t hen provide inf or mat hon lastilying the existing design fcaturce of the Iaci11ty' safety relat ed de syGteWs.
All "no" answers to questions 3 and 4 bove been discussed above.
6.
(1)
Have you conducted a revieu of waintenance and test ing activit Ies to winimite the potential for human error causing tuore than one de division to be unaval1ablet Xtn and (2) do plant procedures prohibit unint enance er t est ing on redundant de divisions at the same tswet M Prairic Island Nuclear Generat ity, Plant Technical Specifications do not have provisions equivalent to Westiny, house Standard Technical Spectficattons.
?.
Are maintenance, surveillance and test procedures regarding station batteries conducted routinely at this plant ? Specifically:
a.
At least once,,or
' du e t w t he following verified to be within acceptabic litrits; I,
pilot call clectvalyt~ seveli M 2.
Specific gravit-or charging current ? M a pecific greyLLy 3.
Float Voltagei Xu 4,
focal bus voltage on float charsei Xu 5.
Physical condition of al! celist Xu b.
A* least once per 92 day, or within 7 days af t er a bat tery discharge, overcharge, or if the pilot cell readings arc ~ outside the 7 day survei11ance requirewenta are the [ollowlng s eri[]cd Io - be vithln accepthbic lituits:
1.
Elcesrolytc 1evel of each cel17 Xu 2.
[he average specific gravity of all cells? M 3.
The specific gravity of each cell?_ M 4.
The average electrolyt e t empar.sture of a representat ive number of cells 7 Xes. everv Stjttell l
S.
The float voltage of each cellt Xu
...a
b Attattient ?
Oc toter ?8,1V91 l' age 4 of $
6.
Ylsually inspect or measure resistante of t ertutnals and ennnectors (lneluding the connectors at the de bus)i Ni; s G $ual inspection la perlotved every entendar quarter atul
- h
- 8 resistance is measured every 6 months c.
ii U.t s 4f f) l8 twnths are the following ver1[ led:
1.
Lnt tutstar f f of each connect hon (by t est Ji M 2.
Physical condillott c' the battery! M
.L 11attery charger capability to deliver rated ampete output to the de bus?
-2' No, please sco the attached diegrains (B20.91 and H20.9 2). The prairio Island !)C sys t ein con!!gutation will not allow load testing of the battery charger without signifIcant internal reconfigt. ration of tho AC input and DC output connectlons. Such reconfiguration would not provide testing of the_ actual battery charger connections during tho-load t est of the bat tery charger.
F.ffective preve-at ive unint enance is perf orined on each hattery charger each refueling outage, Further, each battery charger is rated at 150 ainperes, but the stvady. state load is 35 aniperen or less.
The prairio Island Updated Final Safety Analysis Report. requires the bat tery to be recharged in 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, llowever, por equation 1 in IEEE Standard 940 1985, it will take less than lit hours to recharge a bat tory while carrying the normal load.
4.
The capability of the batt cry to deliver ita desigti daty cycle to the bus? M 5.
Fach individual ce)) voltage is within acceptable litnit s daring the service t est ? Yut d.
At ) cast every 60 twnths, is capacity of each bat tcry verified by performance of a discharge t esti b e.
A t-icast annual 1y, is the bat t ery capacj ty verifivd by performance discharge test, if the batt ery shows slyns of degradation or has reached 85tt of Ihe expected u rvico lifet M
At t at hnerit ?
Oc toter 28,1W1 l' age $ of $
8, Does this pienst have npetational features such that f olluvistg loss of one s.at et y a clat ed de power supply or bus:
Capabili t y is inaint ained lor ens uring cont ittued and adequat e react or a.
cooling? Yes b.
Reactor coolattt sys t ens i ts t er ri t y and isolatJon capability are sna i rt t ai ned ? Les c.
Operating ptocedaves.
Atust rutnent a t ion (1neluding ia dicat ors and annutsciat ors), and cont rol f unct ions are adequa e t o itsil la t e s ys t evis r
required t o tunintain adequat e cot e coalitigi Xyy as 9
If the answer to any part o f q u e.<. t i on
(,,1 o r 8 is no, t hen prwlde your basis f or not pert ornsing t he snaint enance, rurveillance and test procedures described and/or the bases f or not including t he operat Jona! [ cat ut es cit ed, All "no" answers to questionu
'l tend 8 nie dit.cunnid above.
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