NLS9100666, Forwards Response to Generic Ltr 91-06, Resolution of Generic Issue A-30, 'Adequacy of Safety-Related DC Power Supplies.'

Forwards Response to Generic Ltr 91-06, Resolution of Generic Issue A-30, 'Adequacy of Safety-Related DC Power Supplies.'

ML20085L535
Person / Time
Site:	Cooper
Issue date:	10/25/1991
From:	Horn G NEBRASKA PUBLIC POWER DISTRICT
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, NLS9100666, NUDOCS 9111040210
Download: ML20085L535 (7)

Text

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                                              !;uclear Regulatery Commission Attention: Document Control Desk Washington, DC 20555

Subject:

Response to !;RC Ceneric Letter 91-06 Resolution of Generic Issue A-30

                                                                                                               " Adequacy of Safety-Related DC Power Supplies" Cooper I;uclear Station
                                                                                                               !?RC Docket !;o . 50-298, DPR 46 Gentlemen:
                                                !;RC Cenoric Letter (CL) 91-06, " Adequacy of Safety-Related DC Power Supplies *',

was issued on April 26, 1991. The Generic Letter contains requested actions and reporting requirement s for the Resolution of Cenarie Safet-y Issue A-30 (" Adequacy of Safety-Related DC Power Supplies"). As requested by the Generic Letter, attashed is tha !1eb raska Public Power District's (District) response to the questions contained in the enclosure to !;RC Ceneric Letter 91-06. This response is submitted under oath in accordance with the provisions of 10 CFR 50.54(f). Please contact me at this offiec if you have any questions. Sinc rely, in Yc.~~- C . rR) llo rn 1;udlear Power Croup !!anager CRil/tj a :GL91 06 Attachment ec:  !;RC Regional Office Region IV Arlington. TX

                                                                                      !!RC Resident Inspector Cooper I;uclear Station 1

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14139100666 Page 2 October 25, 1991 STATE OF tiEBRASKA )

                              )ss P1ATTE COUtiTY               )

G. R. Ilo r n , beiny, first. duly sworn, deposer and says that he is an authorized representative of t he tiebraska Public Power Dist ric t , a public corporation and political subdivision of the State o f fiebrar.ka ; that he in duly authorized to submit this response on behalf of fiebraska Public Power Dint rlet ; and that the stat etrent y cont atned herein are true to the best of bls knowledge aint bellef l _7e) lm l i o II) Subscribed in ny presence atul sworn to bef ore Ito this 1 b +~h day of _DilokiN , 1991. O4k tiOTARY PUhl.lC GEEAM WIARY4th elIstruka ALotsJ.HUBL 89 My Cema ha Asg. It 1995

Attaclunent to

         .                                                                                                                      NIS9100666 Panc 1 of $

NEBRASKA PUBl.10 POWER DISTRICT'S

                                                                      . RESPONSE TO CENERIC LETTER 91-06 RESOLUTION OF CENERIC ISSUE A-30
                                                  " ADEQUACY OF SAFETY RElATED DC POWER SUPPL.lES"                                              ,

l

                 -itilE0pUCTIOR on April 29, 1991, the NRC issued Concric lettar 91 06, Resolution of Generic l

lasue A 30, " Adequacy of Safety-Rolated DC Powet Supplies". The Concric Letter requested licenace's to provido a written response to tlw followinP, questions within 180 days of the date of the let ter. The ic11owing la the Nebraska Public , Power District's Response to those questlons, i QUESTIONS and 6}iSVIES The following information is to be provided for each unit at each site;

1. Unit: 920ffjtyyclxMLg16110B

2. a. The number of independent redundant divisions of Class IE or safety.

reinted DC power for this plant is IVO m : 125Vp1ElyishtLLand DJyi.ticn II . AniD9R-Q_Elyhinn_LanLDh1Eion_lh

b. The nwnber of functional safety rolated divisions of DC power necossary to attain safe shutdown for thin unit is QHK fi)2 I

                 - 3.               Does the Control Room at this unit have the following separato, indepen-dently annunciated alarms and indientions for each division of DC power?

a, Alarms:

1. Battery disconnect or circuit breaker open?

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• Er211dtd as n Catttt01_E991.ADnuat1AL9LalaIL ~In add 1 Licit, Ann 9Bt11t191LiA_provided_1gtig_hnLigy_Yeltagthy_Lht Charger Irquhle . Alarm and bus voltagt_la_lnillcat ed __and .ngnitored ill r ihL92Dtrol Room. Farlhtrnotedhtnen1LintLcLthe_111atennes.t AxlLthcL_ art _Edmin191En11yth_tenLE93bd31_fRS_IIQCtdattna -

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Attachnent to

     .                                                                                                                                          NLS9100666                                        '

Page 2 of 5

2. Battery charger disconnect or circuit breaker open (both input AC and output DC)? ,

XES: Each Battery Charger is tggvided a " BATTERY CHARGER IE@M.E" Annunclator which alarms on 1.gw AC Irlp1LYAliagb.3&M M Output _ Voltane. and DC Output Breaker Open.

3. DC system ground? YES, 4 DC bus undervoltage?

IES: DC Bus Low Valiage is indfr. gird _ky .. ChgIgor Trouble 6HDnDela_ tor.

5. DC bus overvoltage?

4 IES: _ Cugtsntiv CNS has a separJte. DC Bus __ljjgh Vollagg Annuntia19r3r each bus of both__the 125V and 250V DC Systems. Egyever, a Station Modifisation se.beduled for c02P1f11pD durjyn the onzoing 1121 refueling _p1Legt_wfil CD.mhinLiht_lligh DC Bus Vp11grdLgIms with the C);arner Trouhln_. Alarms. The avecific cause f or the _ Ann _unciator vill then be indicated on g_QtT_.Rgnitor in the ControLEpfm ,

6. _ Battery chargar failure?

YES: Via the Charger Trouble Annunciators.

7. Battery discharse?

Not _specifically. Itswfyrr . annunciat ion is _ prpyided f or a Lo_w DC Bus Voltane. sensed _ git _t.bg bot t ery side of tht_Qharger JQ D.utput Breaker._and 19L.a tharner DG ontnu.l_Araakttar.19. If the charner outnut bItaltr should tripu o Qhargtr_JIsnklg Alarm _would be cenerated, If 1ht latt erv then disclCgge .. Lov D.Q_Eu.s Voltage Atutunplat ion (IgI1g&g(. _the Charner Trouble 6HDMDG.1719Il 11JIglidP3a.

b. Indications:

1. Battery float charge current? YEL

2. Battery circuit output current? 1KL

3. Battery discharge?

IES.L The battary ammeter _.in_provided wlth both__ a charsLAnd l discharne scale.  !

4. Bus voltage? YLL i

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Att A clunent to

           .                                                                                                                                                     NLsp100666 Pap 3 of 5 Does the unit have written procedures for response to the above c.

alarma and indications? YEL 1 l

4. Does the unit have indication of bypassed and inoperable status of circuit  ;

breakers or other devices that can be used to disconnect the bat:ery and battery charger frorn its DG bus and the battery charger from its AC power during maintenance and testing? ] YES: V16lhtGhgIgtr TroublL6Dnulttiator or DC_ Bus B1pXu_ERic_Annuitint.cra , i

5. If the answer to any part of - question 3 or 4 is no, than provi6  :

information justifying the existing desi6n features of the facility's safet-y related DC. Systems, e NPPD's reap 2tlEes to all part s of_ questions 3. pnd 4__vereJ3hyppt . for  ? the reso_onge to _ qutation 3.a ,1. Set _ItappngLig._quentlon 3.a ,1 dp11111DE l 1ht__tK1 Aline _dillE1L eat ures of CNJ, ILIA f e t y relgif d DC_ _ sys t em, f i

6. (1) llave you condeced a review of maintenance and testing activities to minimize the poteu f ca for human error causing more than one DC division to be unavailabic? and (2) Do plant procedures prohibit maintennnce or {

testing on redundant DC divisions at the same time? (1) YEFil._63_ x3 rt of eyerv malnLtn!ulte _9Lita11ng_pInuihtIt_I1Yinx._altd l Approval _ oropjlLis . (2) YES, t if.the facilftg Technical Specifications have provisions equivalent ;o those found-- in tho -Westinghouse and Combustion Engiswering Standard Technical Specifications for maintenance and.surveillar..:c, then question 7 may be skipped - . and o' statement to that effect may ho inserted hero,  ! EFJLitrhttirol. Spin 11Lett.icnLatt.11plJipP311ak1LJ" 1h11 LQ1Mllt101LS

7. Are maintenance, surveillanca, and test procedures regarding static.o l

                                                 ' bat.teries conducted routinely at this plant? Specifically:

a, At 1 cast. once por seven days are the following verified to bu within I acceptable limits: ,

1. -Pilot cell electrolyte levol? YEL ---

                                                                        ?.                 Specific gravity or charging current? yfL                                              ,

3. Float voltage? yRL 4 Total bus voltage on iloat charge? yEL

, i S. Physical condition of alI colh? YEL ,

At t achiteent t o

     .                                                                                                                                                                                                      111.S9100666 Page 4 of $

b. At least once per 92 days, or within seven days after a battery discharge, overcharge, or if the pilot ec11 readings are outside the seven day surveillance requirements, are the following verified to be within acceptable limits:

1. F.lectrolyte level of each cell? XEL

2. The average specific gravity of all cell? YEL

3. *ihe specific gravity of each cell? XEL 4 The as orage electrolyte temperature of a representativo number of cellsi Ml_CES_dtes not spttifical1y enIIg1 Alt _AltevenFA.tif11tElJ12 urntrantre_.eL_1_IsPts1.rtttn111t__numkrI._ of crils. The_GliE Irghniea1 Spic 111gptien} regyirt_ _11utt the e 1e cir_qlylt umpnature of a rupresent aLlyr itJmhir of .stlLhtv_ithin 5?F IlL13 reou!remsnLis simi1ar to tlic_ Ell.itlitj_ftygtagg but morm restrictive in that the oveInl1 rans'e for All_.ggils is 10?F.

Thtti10re. any hadLwrah_ttl1 v.LUJtc 151r11tifit! Land _.r.eIrrt11Yn IhrAnttti._af.lf.qu1Itd_v1Ll ltiLiatta

5. The float voltage of each cell? YEL

6. Visually inspect or measure reslutance of terminals and connectoru (.acluding the connectors at the DC bun)? YLL o c. At Icast evety 18 months, are the following verified:

1. Low resistance of each connection (by test)? IfL l

iI (~ i 2. Physical condition of the battery? 1[S,

3. ra ttely (narger capability to deliver rated ampero output to the DC bus? XEL

o. The capabilit y of the hattery to deliver it s denign duty cycle to the DC bus? XLL

5. Each individual cell is within accepcable limits during the service teut? YEL w

d. At least every 60 months, is the capacity of each hattery verified by performance of a discharge test? XEL e At least annually, in the battery capacity verified by perfor.ance discharge test, if the battery shows signs of degradation or has reached 85t of th( expected service life? 1EL

Attaclunent tn

       .                                                                                                                                            NLS9100666 Pago 5 of $

8. Does this plant have operational features such that following loss of one safety related DC power supply or bus:

a. Capability is inaintained for ensuring continued and adequate reactor cooling? 1ES.,

b. Reactor coolant systea integrity and isolation capability are snaintained? XEL.

l

c. Operating proceduros, ins t: urnentation (including indicators and I annunciators), and control functions are adequate to initiato I systerns as required to maintain adequate core cooling? XES. I

9. If the answer to any part of questions 6, 7, or 8 is no, then provido your basis for not performing the inaintenance, surveillance and test procedures ,

described and/or the hanos for not including the operational features j' cited. I HPID'_s_ responses to all carts of ouentigna 6. 7. and 8. vere _ven. exg.gp1 inr the response to gnestion.2.b.4. S et ,tgAppas e t o qugAt.1.pn 7 . b . 4 for 1%KLLs i i t 1 I i f i I e.-,,, . . . . . r,-.%. ._-,-,......m.-. ...--,-..,-.__..~...-...,.~s____-._-._.,_.-_....m~~.~,..._-m_~-~---

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