ML17223B295

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

ML17223B295
Person / Time
Site:	Saint Lucie
Issue date:	10/28/1991
From:	Bohlke W FLORIDA POWER & LIGHT 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, L-91-291, NUDOCS 9111060225
Download: ML17223B295 (27)

Text

ACCELERATED DISTRIBUTION DEMONST TION SYSTEM 4 REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)ACCESSION NBR:9111060225 DOC.DATE: 91/10/28 NOTARIZED:

YES FACIL:50-335 St.Lucie Plant, Unit 1, Florida Power&Light Co.50-389 St.Lucie Plant, Unit 2, Florida Power&Light Co.AUTH.NAME AUTHOR AFFILIATION BOHLKE,W.H.

Florida Power&Light Co.RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

Responds to Generic Ltr 91-06,"Resolution of Generic Issue A-30 Adequacy of Safety-Related DC Power Supplies." NRC requested licensees to provide written responses to questions in Encl 1 of generic ltr within 180 days of ltr.DISTRIBUTION CODE: AOOID COPIES RECEIVED:LTR i ENCL Q SIZE: TITLE: OR Submittal:

General Distribution NOTES DOCKET 05000335 05000389 D RECIPIENT ID CODE/NAME PD2-2 LA NORRIS,J INTERNAL: ACRS NRR/DET/ESGB NRR/DST 8E2 NRR/DST/SICB8H7 NUDOCS-ABSTRACT OGC/HDS3 RES/DS IR/EI B EXTERNAL: NRC PDR COPIES LTTR ENCL 1 1 2 2 6 6 1 1 1 1 1 1 1 1 1 0 1 1 1 1 RECIPIENT ID CODE/NAME PD2-2 PD NRR/DET/ECMB 7D NRR/DOEA/OTSBll NRR/DST/SELB 7E NRR/DS~TSRXB 8E O,C/'~LB'G FILEEO1.NSIC COPIES LTTR ENCL 1 1 1 1 1 1 1 1 1 1 1 0 1 1 1 1 D D D NOTE TO ALL"RIDS" RECIPIENTS:

A D D PLEASE HELP US TO REDUCE WASTE!CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT.20079)TO ELIMINATE YOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!TOTAL NUMBER OF COPIES REQUIRED: LTTR 24 ENCL 22 P.O.Box14000, Juno Beach, FL 33408-0420 October 28, 1991 L-91-291 10 CFR 50.54(f)U.S.Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C.20555 Gentlemen:

RE: St.Lucie Unit Nos.1 and 2 Docket Nos.50-335 and 50-389 Generic Letter 91-06 Res onse Attachments 1 and 2 are the Florida Power and Light Company response to Generic Letter 91-06"Resolution of Generic Issue A-30 Adequacy of Safety-Related DC Power Supplies" for St.Lucie Units 1 and 2 respectively.

On April 29,~1991, the NRC issued Generic Letter 91-06 which provided the results of its evaluation of Generic Issue A-30.The evaluation determined that certain maintenance, surveillance, and monitoring provisions are appropriate for safety-related dc systems.In order to determine whether any site specific staff action would be required, the NRC requested licensees to provide written responses to the questions in Enclosure 1 of the Generic Letter within 180 days of the date of the letter.The attached responses for St.Lucie Unit 1 and 2 are provided pursuant to Section 182 of the Atomic Energy Act of 1954, as amended, and 10 CFR 50.54(f).Please contact us if there are any questions about this submittal.

Very truly yours, W.H.Bohlke Vice President Nuclear Engineering and Licensing WHB/GRM/kw cc: Stewart D.Ebneter, Regional Administrator, Region II, USNRC Senior Resident Inspector, USNRC, St.Lucie Plant DAS/PSL 0547-91!9iii060225 9ii02S PDR ADOCK 05000335 P PDR:9 an FPL Group company cp I~1 A s F St.Lucie Unit Nos.1 and 2 Docket Nos.50-335 and 50-389.Generic Letter 91-06 Res onse STATE OF FLORIDA))COUNTY OF PALM BEACH)SS~W.H.Bohlke being first duly sworn, deposes and says: That he is Vice President, Nuclear Engineering and Licensing for the Nuclear Division of Florida Power 6 Light Company, the Licensee herein;That he has executed the foregoing document;that the statements made in this document are true and correct to the best of his knowledge, information and belief, and that he is authorized to execute the document on behalf of said Licensee.W.H.Bohlke Subscribed and sworn to before me this~cP>aay or 19'P/NOTARY PUBLIC, in d for the County of Palm Beach, State of Florida ffotary Public, State of Florfda My Comm.Exp.Feb.18, 1995 My Commission expires Bonded thruPLGHARD Ins.Aaen 0~I 1~~>~9~"'~hi~o*>

ATTACHMENT 1 ST.LUCIE UNIT 1 QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE Q-2.a Q 2.b Q-3.a Unit The number of independent redundant divisions of class 1E or safety-related DC power for this plant.(Include any separate Class 1E or Safety-related DC, such as any DC dedicated to the diesel generators.)

Thc number of functional safety-rclatcd divisions of DC power necessary to attain safe shutdown for this unit.Does the control room at this unit have thc following separate, indepcndcntly annunciated alarms for each division of DC power?1.Battery disconnect or circuit breaker open?R-1.St.Lucie Unit 1 Docket No.50-335 R-2.a.St.Lucie Unit 1 has two (2)independent redundant divisions of class 1E or safety-related DC Power designated 1A and 1B.Each subsystem consists of a 125 volt DC Bus dcsignatcd 1A (1B), a 125 volt safety-related battery dcsignatcd 1A (1B), and 2 safety-related 125 volt battery chargers designated 1A and 1AA (1B and 1BB).In addition, a swing bus dcsignatcd 1AB with a single 125 volt DC battery charger dcsignatcd 1AB can bc aligned to either thc 1A bus or the 1B bus.R-2.b.St.Lucie Unit 1 requires onc (1)of the functional safety-rclatcd divisions of DC power, either A or B, to attain safe shutdown.R-3.a.St.Lucie Unit 1 has thc following annunciated alarms in the control room: 1.Ycs, an open battery disconnect or circuit breaker is alarmed by ANNUNCIATORS A-30 or B30.2.Battery charger disconnect or circuit breaker open (both input AC&output DC)'?A-30 (B-30)"125V DC BUS 1B (1A)UN DERVOLTAGE/MAIN BATTERY BREAKER." 2.Ycs, an open battery charger disconnect or circuit breaker (either input AC or output DC)is alarmed by ANNUNCIATORS A-20, B-20, Z 9,&Z 10.3.DC system ground?A-20 (B-20)"125V DC BUS 1B (IA)BA7L CHGR./BATT.

RM FAN TROUBLE" Z-9 (Z-10)BATTERY CHARGER 1AA (1BB)TROUBLE" 3.Ycs, a DC system ground is alarmed by ANNUNCIATORS A-10&B-10.4.DC bus under voltage?A-10 (B-10)"125V DC BUS 1B (1A)GROUND" 4.Yes, a DC bus undervoltage is alarmed by ANNUNCIATORS A-30&B-30 5.DC bus over voltage?A-30 (B-30)Same annunciator as response R-3.a.1 5.Ycs, a DC bus ovcrvoltage is alarmed by ANNUNCIATORS A-20&B-20.A-20 (B-20)Same annunciator as response R-3.a.2 In addition high voltage causes the battery charger shutdown and trouble alarm.

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QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE 6.Battery charger failure?6.Yes, a battery charger failure is alarmed by ANNUNCIATORS A-20&B-20 Q-3.b 7.Battery discharge?

Docs thc control room at this unit have thc following separate independent indications for each division of DC power'?1.Battery float charge current'?A-20 (B-20)Same annunciator as response R-3.a.2 7.No, St.Lucie Unit 1 docs not have a bauery discharge alarm.Sce thc response to Q-5 for justification.

R-3.b.St.Lucie Unit 1 has the following indications in the control room: 1.No, Unit 1 does not have battery float current indication in thc control room.Sce the response to Q-5 for gustiflcation.

Q-3.c 2.Battery circuit output current?3.Bauery discharge?

4.Bus voltage?Does the unit have written proccdurcs for response to the alarms (3.a 1-7)and indications (3b.1<)?2.No, Unit 1 does not have battery circuit output current indication in thc control room.Scc thc response to Q-5 for justification.

3.No, Unit 1 does not have battery discharge indication in the control room.Scc thc response to Q-5 for justification.

4.Ycs, DC bus voltage indication is provided in the control room by volt mctcrs VM-1001&VM-1002 and indcpcrfdcnt white indicating lights.R-3.c.Ycs, written procedures for the response to thc alarms (R-3.a.1-7)

&Indications (R-3.b.14)are listed below: 3.a.1-7 (Alarms)OP 1-0960020"125V DC SYSTEM NORMAL OPERATION" ONOP 1-0030131"PLANT ANNUNCIATOR

SUMMARY

" ONOP 1M60030"DC GROUND ISOLATION" Does this unit have indication of bypassed and inoperable status of circuit brcakcrs or other devices that can bc used to disconnect thc battery and thc battery charger from its DC bus and the battery charger from its AC power source during maintenance or testing?3.b.I<(indications)

OP 1-0960020 125V DC SYSTEM NORMAL OPERATION" ONOP 1~30136"LOSS OF A SAFETY RELATED DC BUS" RP Ycs, bypass and/or inoperable status of DC output or AC input circuit brcakcrs is provided by thc control room annunciators identified in R-3, specifically A-20 (B-20)&, A-30 (B-30)provide annunciation of battery charger trouble including AC power failure, and misalignment of battery output breakers.Howcvcr, there is no specific alarm or indication provided to identify an inoperable circuit breaker.Sce the response to Q-5 for justification.

'l~q QUESTION'O.GENERIC LETTER REQUEST FPL RESPONSE If thc answer to any part of question 3 or 4 is no, then provide information justifying the existing design features of the facility's safety-related DC systems.R-3.a.7 R-3.b.1 R-3.b.2 R-3.b.3 RP Instead of dcvcloping Ec supplying thc justification, FPL may commit to perform thc evaluations during the pcrformancc of the IPE for scvcre accident vulnerabilitics Has FPL conducted a review of maintenance and testing activities to minimize the potential for human error causing more than onc (1)DC division to be unavailable?

R-5 A nccd has not been identified for an alarm in question 3.a.7 (battery discharge alarm)or thc control room indications in questions 3.b.1 (battery Iloat current), 3.b.2 battery circuit output current), or 3.b.3 (battery discharge indicators) nor is any rccommcndcd by IEEE 308-1971 for these parameters.

For the inoperable status indication of question 4, thc control room annunciators A-20 (B-20)and A-30 (B-30)provide annunciation of battery charger trouble including AC power failure and misalignment of the battery output brcakcrs.There is no specific alarm or indication provided to identify an inoperable circuit breaker and none is recommended by IEEE 308-1971.An inoperable circuit breaker'that will not close or that will trip prematurely would bc dctcctcd by onc of the alarms listed above.An inopcrablc circuit breaker that will not open is an undctcctable failure via normal annunciators since its normal operating mode is thc closed position.This situation will not interfere with battery operation.

R4.1 Ycs, St.Lucic Plant has pcrformcd a human factors rcvicw of the clcctrical maintenance proccdurcs for DC distribution cquipmcnt.

The review was part of a maintcnancc procedure upgrade program but was not pcrformcd specifically to prevent human error from causing more than one DC division to become unavailablc.

Q-7.a Do plant procedures prohibit maintenance or testing on redundant DC divisions at thc same time?If the facility Technical Specifications for this unit have provisions equivalent to those found in the Combustion Engineering Standard Tcchnical Specifications for maintenance and surveillance?

Are maintenance, surveillance and test proccdurcs requiring station battcrics conducted routinely at this plant?At least bncc pcr 7 days arc the following verified to bc within acccptablc limits: R4.2.Plant Administrative Procedure (AP)AP 0010142"Manipulation of Sensitive Systems" prohibits maintenance on two (2)portions of a sensitive system or on two separate scnsitivc systems at the same time.The 125v DC electrical system is a dcsignatcd sensitive system in AP 0010142.R-7 Thc St.Lucic Unit 1 Tcchnical Specifications have provisions similar to the Combustion Engineering Standard Tcchnical Specifications for maintenance and survcillancc, howcvcr bccausc of thc differcnccs a response to question 7 is be provided.Ycs, as detailed in the response to questions 7.a Through 7.e below, proccdurcs for maintcnancc, surveillance, and testing are routinely conducted on the station battcrics.

R-7.a Maintenance Procedure MP 0960163 provides the weekly tests and inspections.

1.Pilot cell electrolyte level?2.Specific gravity and/or charging current?1.Ycs, MP 0960163 verifies pilot cell electrolyte level at wcckly intervals.

2.Ycs, MP 0960163 vcrifics charging current at the output shunt mctcr connections of each battery charger using a DVOM and the charging current using the installed metering at wcckly intervals.

In addition, MP 0960163 tests the specific gravity of each battery pilot cell at wcckly intervals to verify that they are within acceptable limits.

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QUESTION NO.GENEMC LETTER REQUEST FPL RESPONSE 3.Float voltage?3.Ycs, MP 0960163 vcrifics the battery float voltage using installed panel mctcring at the battery chargcrs at wcckly intervals.

Q-7.b 4.Total bus voltage on float charge?S.Physical condition of all cells?At least once pcr 92 days, or within 7 days aflcr a battery discharge, overcharge, or if pilot cell readings are outside the 7 day surveillance rcquircmcnts are the following verified to be within acccptablc limits: 1.Electrolyte Icvcl in each cell?4.Ycs, MP 0960163 verifies battery bus voltage using the installed panel metering at thc DC buses at weekly intervals.

S.Ycs, MP 0960163 visually inspects thc individual battery cells for cracks, loose material, dust, dirt, corrosion, and clcctrolytc leaks.R-7.b.Maintenance Procedure MP 0960164 provides the monthly inspections and tests that correspond to the quarterly rcquircmcnts of question 7.b.Note: The parameters of question 7.b are verifie if thc pilot cell readings arc outside the 74ay surveillance rcquircmcnts for thc batterics, pcr periodic Maintcnancc Proccdurc MP 0960163.Thcsc paramctcrs arc also vcrificd aRcr a discharge test of thc batterics pcr the requirements of Maintenance Proccdurcs MP 1%960062&MP 1M60063 for thc 1A Ec IB battcrics rcspcctivcly.

An overcharge of the station battcrics is not anticipated during thc lifetime of thc batteries, so recovery from an overcharge of the battcrics is not procedurally documented.

If such an overcharge occurred, recommendations to verify the integrity of the batteries would be considered, and would likely include the paramctcrs vcrificd in thc monthly battery maintenance

.procedure as a minimum..1.Ycs, MP 0960164 verifies the elcctrolytc level at monthly intervals.

2.The average specific gravity of all cells?3.The specific gravity of each cell?4.The average electrolyte tcmpcrature of a rcprcscntative number of cells?S.The float voltage of each cell?6.Visually inspect or mcasurc resistance of terminals and connectors (including the connectors at the DC bus)?2.Ycs, MP 0960164 mcasurcs thc specific gravity of all cells and then calculates the average specific gravity of the cells monthly.3.Ycs, MP 0960164 records the specific gravity of each cell monthly.4.Ycs, MP 0960164 Calculates thc average clcctrolytc temperature of the battery monthly.S.Ycs, MP 0960164 records the battery float voltage monthly.6.Ycs, MP 0960164 visually inspects all battery connections monthly.If any visual corrosion is noted, microwhm readings of the affcctcd battery connections arc pcrformcd.

However, thc connections at the DC bus are not verified by this visual inspection since they are not in a corrosive environment and have not bccn noted to be corroded in any past periodic maintcnancc pcrformcd on this equipment.

0 1 I l QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE Q-7.c At least cvcry 18 months arc thc following verified: 1.Low resistance of each connection (by test)R-7.c Maintcnancc Procedures MP 14960062, MP 1-0960063, MP 0960150, and MP 0960165 provide the 18 month tests and inspections.

l.Ycs, MP 0960150 verifies the resistance of all battery intcr~cll and terminal connections at 18 month intervals.

2.Physical condition of the battery'2.Ycs, MP 0960150 includes a physical inspection of all battery cells at 18 month intervals.

3.Battery charger capability to deliver rated ampcrc output to the DC bus?3.Ycs, MP 0960165 verifie the capability of the battery chargcrs to dclivcr rated output to thc DC bus cvcry 18 months.Q-7.d Q-8.a 4.The capability of the battery to deliver its design duty cycle to the DC bus?5.Each individual cell voltage is within acceptable limits during the service test?At least cvcry 60 months, is capacity of each battery verified by performance of a discharge test?At least annually, is thc battery capacity verified by performance discharge test, if thc battery shows signs of degradation or has reached 85%of expected life?Docs thc unit have operational features such that following loss of one safety-related DC power supply or bus: a., Capability is maintained for ensuring continued and adequate reactor cooling'4.Ycs, MP 14960062&MP 14960063, verify the capability of the batteries 1A&, 1B respectively to deliver their design duty cycle to thc DC bus at 18 month intervals.

5.Ycs, MP 1-0960062&MP 1-0960063 verify the individual cell voltages of thc batterics 1A&1B rcspcctivcly at 18 month intervals.

R-7.d.Ycs, Maintenance Procedures MP 1-0960151&MP 14960152 verify the capacity of thc station batteries by performance of a discharge test at 60 month intervals for the 1A&1B battcrics rcspcctivcly.

R-7.e.Ycs, Maintenance Proccdurcs MP 14960151&MP 14960152 provide for the annual test and inspections and performance of a battery discharge test if thc battery shows signs of degradation or has reached 85 percent of the expcctcd service life.R-8.a.Ycs UFSAR Section 8.3.discusses how the capability is maintained for ensuring continued and adequate reactor cooling following thc loss of onc safety-related DC power supply or bus.Load groups A and B are each capable of supplying thc minimum DC power requirements to safely shutdown the plant and/or mitigate the consequences of a LOCA.Q-g.b Docs thc unit have operational fcaturcs such that following loss of one safcty-related DC power supply or bus: b.Reactor coolant system integrity and isolation capability arc maintained?

R-8.b.Ycs, UFSAR Section 8.3 discusses how reactor coolant system integrity (RCS)and isolation capability are maintained following a loss of one safety-rclatcd DC power supply Howcvcr, in Operational Modes 1 through 4 thc loss of one safety-related DC bus will initiate a reactor trip signal in thc reactor protection system and will cause the PORV in the opposite train to open.Off-Normal Operating Procedure ONOP 14030136 directs thc operator to close the associated block valve which restores RCS integrity.

Sce the response to Q-9 for justification.

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~~1 QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE Q-g.c Does the unit have operational features such that following loss of onc safety-related DC power supply or bus: c.Operating procedures, instrumentation (including indicators

&annunciators), and control functions are adequate to initiate systems as required to maintain adcquatc core cooling?R-8.c Ycs, Off Normal Operating Procedure ONOP 1-0440030,"Shutdown Cooling Off-Normal" provides guidance for realignment of thc shutdown cooling system should a loss occur.Additionally, alternate means of decay heat removal are provided in accordance with Generic Letter 88-17, within this proccdurc.

Off-Normal Operating Proccdurc ONOP 14030136"Loss of Safety-Related DC Bus" provides guidance for loss of onc safety related DC bus.If the answer to any part of question 6, 7, or 8 is no then provide the basis for not performing thc maintenance, surveillance, and/or test procedures described and/or the bases for not including the operational features cited.Unit 1 control room annunciators are powered from the IAB DC bus, allowing manual realignment if required to an operablc 1A or 1B DC bus.The opening of one PORV at power is bounded by thc analysis in section 15.2 of thc UFSAR.The Off-Normal Operating Procedure provides thc operator with guidance for loss of onc safety-related DC bus.R-8.b Instead of dcvcloping Ec supplying the information in response to Question 9, FPL may commit to further evaluate thc nccd for such provisions during the performance of thc IPE for severe accident vulncrabilitics.

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~~~~~ATTACHMENT 2 ST.LUCIE UNIT 2 QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE Q-2.a Q-2.b Q-3.a Unit Thc number of independent redundant divisions of class 1E or safety-related DC power for this plant.(Include any separate Class 1E or Safety-related DC, such as any DC dedicated to the diesel generators.)

The number of functional safety-related divisions of DC power necessary to attain safe shutdown for this unit.Does the control room at this unit have the following scparatc, indcpcndcntly annunciated alarms for each division of DC power'1.Battery disconnect or circuit brcakcr open?R-1.St.Lucie Unit 2 Docket No.50-389 R-2.a.St.Lucie Unit 2 has two (2)independent redundant divisions of class 1E or safety-related DC power designated 2A and 2B.Each subsystem consists of a 125 volt DC bus dcsignatcd 2A (2B), a 125 volt, safety-related battery designated 2A (2B), and two (2)safety-related 125 volt battery chargcrs designated 2A and 2AA (2B and 2BB).In addition, a swing bus designated 2AB with a single 125 volt battery charger designated 2AB can be aligned to either the 2A or the 2B bus.R-2.b.St.Lucie Unit 2 requires one (1)of the functional safety-rclatcd divisions of DC power, either 2A or 2B, to attain safe shutdown.R-3.a St Lucic Unit 2 has the following annunciated alarms in the control room: 1.Yes, an open battery disconnect or circuit breaker is alarmed by ANNUNCIATORS A48&B-50.A<8 (B-50)"125V DC BATT.2B (2A)DISCHARGE HI/BKR OPEN" 2.Battery charger disconnect or circuit brcakcr open (both input AC&output DC)?2.Yes, an open battery charger disconnect or circuit breaker (cithcr input AC&output DC)is alarmed by ANNUNCIATORS A-20&B-20.A-20 (B-20)"125V DC 2B/2BB (2A/2AA)BATT.CHGR.2B/2BB (2A/2AA)TROUBLE" 3.DC system ground?3.Yes, a DC system ground is alarmed by ANNUNCIATORS A-10&B-10.A-10 (B-10)"125V DC BUS 2B/2BB (2A/2AA)GROUND" n 4.DC bus under voltage?4.Ycs, a DC bus undervoltage alarm is provided by ANNUNCIATORS A-30&B-30.A-'30 (B-30)"125V DC BUS 2B (2A)UNDERVOLTAGE" QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE 5.DC bus over voltage'?5.Yes, a DC bus overvoltage alarm is provided by ANNUNCIATORS A-20&B-20.A-20 (B-20)same annunciator as response R-3.a.2 In addition, high voltage causes battery charger shutdown&trouble alarm.6.Battery charger failure?6.Yes, a battery charger failure alarm is provided by ANNUNCIATORS A-20&B-20.A-20 (B-20)same annunciator as response R-3.a.2 7.Battery discharge'?

7.Ycs, a battery discharge alarm is provided by ANNUNCIATORS AA8&B-50.A48 (B-50)same annunciator as response R-3.a.l Q-3.b Q-3.c Docs the control room at this unit have the following separate indcpcndcnt indications for each division of DC power?1.Battery float charge current?2.Battery circuit output current?3.Battery discharge?

4.Bus voltage?Does thc unit have written procedures for response to thc alarms (3.a 1-7)and indications (3b.1-4)?R-3.b.St.Lucie Unit 2 has the following indications for each division of DC power: 1.No, Unit 2 does not have float current indication in the control room.See the response to Q-5 for justification.

', 2.Yes, battery circuit output current indication is provided in the control room by AM-1801&AM-1802.3.Yes, battery discharge indication is provided in the control room by AM-1801&AM-1802.4.Bus voltage indication is provided in the control room by volt meters VM-1001&VM-1002 and indcpcndcnt white indicating lights.R-3.c.Ycs, written procedures for the rcsponsc to the alarms (R-3.a.1-7)

&indications (R-3.b.ld) are listed below: R-3.a.1-7 (Alarms)OP 2-0960020"125V DC SYSTEM NORMAL OPERATION" ONOP 24030131"PLANT ANNUNCIATOR

SUMMARY

" ONOP 2-0960030"DC GROUND ISOLATION" R-3.b.1<(indications)

OP 2-0960020"125V DC SYSTEM NORMAL OPERATION" ONOP 2%030136"LOSS OF A SAFETY RELATED DC BUS" 4>>V ,II QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE Docs this unit have indication of bypassed and inoperable status of circuit breakers or other dcviccs that can be used to disconnect the battery and the battery charger from its DC bus and the battery charger from its AC power source during maintenance or testing?RP Ycs, bypassed and/or inopcrablc status indication is provided by control room annunciators A<8 (B-50)for an open battery discharge breaker.Common trouble alarms A-20 (B-20)annunciate for a loss of AC power to the battery chargers.However, there is no specific alarm or indication provided to identify an inoperable circuit breaker;sec thc response to Q-5 for justification.

Q-5 Q4.1 If the answer to any part of question 3 or 4 is no, then provide information justifying the existing design features of the facility's safety-related DC systems.R-3.a.7 R-3.b.1 R-3.b.2 R-3.b.3 RA Instead of dcvcloping

&supplying the justification, FPL may commit to perform the evaluations during the performance of thc IPE for severe accident vulnerabilitics Has FPL conducted a review of maintenance and testing activities to minimize the potential for human error causing morc than one (1)DC division to be unavailablc?

R-5 A need has not been identified for the indication in question 3.b.1 (battery float current)nor is any rccommcndcd by IEEE 308-1971 as modified by R.G.1.32, Rcv 0 for this paramctcr.

For thc inoperable status indication of question 4, thc control room annunciators A<8 (B-50)provide indication, of an open battery output breaker.Common trouble alarms A-20 (B-20)provide annunciation of battery charger trouble including AC power failure.There is no specific alarm or indication provided to identify an inoperable circuit breaker and none is rccommcndcd by IEEE 308-1971 as modified by R.G.1.32, Rcv 0.An inoperable circuit breaker that will not close or trip prcmaturcly would be detected by one of thc alarms listed above.An inoperable circuit breaker that will not open is an undetectable failure via normal annunciators since its normal operating mode is the closed position.This situation will not interfere with battery operation.

R4.1 Yes, ST.Lucio plant has performed a review of thc clcctrical maintenance proccdurcs regarding DC distribution equipment with rcspcct to human factor concerns.The rcvicw was performed as part of a maintenance procedure upgrade program but was not performed specifically to prcvcnt human error from causing more than one DC division to become unavailable.

Q-6.2 Do plant procedures prohibit maintenance or testing on redundant DC divisions at the same time?R-6-2 Plant Administrative Procedure (AP)AP 0010142"Manipulation of Scnsitivc Systems" prohibits maintenance on two (2)portions of same sensitive system or on two separate sensitive systems at the same time.The 125v DC electrical system is a designated sensitive system in AP 0010142.If the facility Tcchnical Specifications for this unit have provisions equivalent to those found in the Combustion Engineering Standard Technical Specifications for maintenance and surveillance?

Arc maintenance, surveillance and test proccdurcs requiring station batterics conducted routinely at this plant?R-7 Thc St.Lucie Unit 2 Tcchnical Specifications have provisions similar to the Combustion Engineering Standard Tcchnical Specifications for maintenance and surveillance,, however because of the differences the response to question 7 is be provided.Yes, as detailed in the response to questions 7.a through-7.e below, procedures for maintenance, surveillance, and testing arc routinely conducted for the station battcrics.

IE K+~Q I~As s QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE Q-7.a At least once pcr 7 days are the following verified to be within acceptable limits: R-7.a Maintenance Procedure MP 0960163 provides the weekly (7 day survcillanccs) tests and inspections.

1.Pilot cell electrolyte level?1.Yes, MP 0960163 verifies pilot cell electrolyte level at weekly intervals.

2.Specific gravity and/or charging current?2.Yes, MP 0960163 verifies charging current at the output shunt meter connections of each battery charger using a DVOM and the charging current using the installed metering at weekly intervals.

In addition, thc specific gravity of each battery pilot cell is tested at weekly intervals to verify that they are within acceptable limits.3.Float voltage?3.Yes, MP 0960163 verifies the battery float voltage using installed panel metering at the battery chargcrs at weekly intervals.

4.Total bus voltage on float charge?4.Ycs, MP 0960163 verifies battery bus voltage using the installed panel metering at the DC buses at wcckly intervals.

Q-7.b 5.Physical condition of all cells?At least once pcr 92 days, or within 7 days after a battery discharge, ovcrchargc, or if pilot cell readings are outside the 7 day surveillance requirements arc the following verified to be within acceptable limits: 1.Elcctrolytc level in each cell?5.Ycs, MP 0960163 visually inspects thc individual battery cells for cracks, loose material, dust, dirt," corrosion, and electrolyte leaks.R-7.b.Maintenance Procedure MP 0960164 provides thc monthly inspections and tests that corrcspond to the quarterly requirements of question 7.b.NOTE: The parameters of question 7.b are verifie if the pilot cell readings are outside thc 74ay surveillance requirements for thc batteries, per periodic Maintenance Proccdurc MP 0960163.These paramctcrs are also vcrificd aflcr a discharge test of the batteries per the requirements of Maintenance Procedures MP 2-0960062, Ec MP 24960063 for the 2A&2B batteries respectively.

An overcharge of the station battcrics is not anticipated during thc lifctimc of the batteries, so recovery from an overcharge of the batteries is not procedurally documcntcd.

If such an overcharge occurred, recommendations to verify the integrity of the battcrics would bc considered, and would likely include the parameters verified in the monthly battery maintenance procedure as a minimum.2.The average specific gravity of all cells?3.The specific gravity of each cell?4.The average electrolyte tcmpcrature of a representative number of cells?1.Ycs, MP 0960164 verifies the electrolyte lcvcl at monthly intervals.

2.Ycs, MP 0960164 measures thc specific gravity of all cells and then calculates thc average specific gravity of the cells monthly.3.Yes, MP 0960164 records the spcciflc gravity of each cell monthly.4.Ycs, MP 0960164 calculates the avcragc clcctrolytc tcmpcraturc of the battery monthly.

'-c" Aa s' n QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE Q-7.c 5.The float voltage of each cell?6.Visually inspect or measure resistance of terminals and connectors (including the connectors at the DC bus)'?At least every 18 months are the following verified: 1.Low resistance of each connection (by test)5.Ycs, MP 0960164 records the battery float voltage'onthly.6.Ycs, MP 0960164 visually inspects all battery connections monthly.If any visual corrosion is noted, microwhm readings of the affcctcd battery connections are performed.

However, the connections at thc DC bus are not vcrifled by this visual inspection since they are not located in a corrosive cnvironmcnt and have not been noted to bc corroded in any past periodic maintenance performed on this cquipmcnt.

R-7.c Maintenance Procedures MP,2-0960062, MP 2-0960063, MP 0960150,&MP 0960165 provide the 18 month tests and inspections.

1.Ycs, MP 0960150 verifies the resistance of all battery inter-cell and terminal connections at 18 month intervals.

2.Physical condition of thc battery?3.Battery charger capability to deliver rated ampere output to thc DC bus'?2.Ycs, MP 0960150 includes a physical inspection of all battery cells at 18 month intervals.

3.Ycs, MP 0960165 verifies the capability of the battery chargcrs to deliver rated output to the DC bus every 18 months.Q-7.d Q-7.e Q-8.a.4.The capability of thc battery to deliver its design duty cycle to the DC bus?5.Each individual cell voltage is within acceptable limits during the service test?At least every 60 months, is capacity of each battery verified by performance of a discharge test?At least annually, is the battery capacity verified by performance discharge test, if thc battery shows signs of degradation or has rcachcd 85%of expected life?Does the unit have operational features such that following loss of one safety-rclatcd DC power supply or bus: a.Capability is maintained for ensuring continued and adequate reactor cooling?4.Ycs, MP 2-0960062&MP 2-0960063 verify the capability of the batteries 2A&2B respectively to dclivcr their design duty cycle to thc DC bus at 18 month intervals.

5.Ycs, MP 2-0960062&MP 2-0960063 verify the individual cell voltages of the batteries 2A&2B respectively at 18 month intervals.

R-7.d.Ycs, MP 2-0960151&MP 2-0960152 verify the capacity of the station batteries by performance of a discharge test at 60 month intervals for the 2A&2B batteries respectively.

R-7.e.Ycs, Maintenance Procedures MP 2-0960151&MP 2-0960152 provide the annual tests and inspections and provide for thc battery discharge test if the battery shows signs of degradation or if the battery has reached 85 percent of the expcctcd service life.R-g.a.Ycs, UFSAR Section 8.3.discusses how the capability is maintained for ensuring continued and adcquatc reactor cooling following the loss of onc safety-related DC power supply or bus.Load groups A and B are each capable of supplying the minimum DC power requirements to safely shutdown the plant.

l' QUESTION NO.GENERIC LETTER REQUEST FPL RESPONSE Q-8.b Docs the unit have operational features such that following loss of onc safety-related DC power supply or bus: b.Reactor coolant system integrity and isolation capability are maintained?

R-8.b.Yes, UFSAR Section 8.3 discusses how reactor coolant system integrity (RCS)and isolation capability are maintained following a loss of one safety-related DC power supply.However, in Operational Modes 1 through 4 the loss of one safety-rclatcd DC bus will initiate a reactor trip signal in the reactor protection system and will cause the PORV in the opposite train to open.Off-Normal Operating Procedure ONOP 2%030136 directs the operator to close the associated block valve which restores RCS integrity.

Scc the response to Q-9 for justification.

Q-g.c Does the unit have operational features such that following loss of onc safety-rclatcd DC power supply or bus: c.Operating procedures, instrumentation (including indicators

&annunciators), and control functions are adequate to initiate systems as rcquircd to maintain adequate core cooling?R-8.c Off Normal Operating Procedure ONOP 2-0440030,"Shutdown Cooling Off-Normal" provides guidance for realignment of thc shutdown cooling system should a loss of one safety-related DC bus occur.Additionally, alternate means of decay heat removal are provided in accordance with Generi Letter 88-17, within this procedure.

Off-Normal Operating Proccdurc ONOP 2-0030136"Loss of Safety-Related DC Bus" provides guidance for loss of onc safety-related DC bus.Unit 2 control room annunciators are powered from the vital AC bus.If thc answer to any part of question 6, 7, or 8 is no then provide thc basis for not performing the maintenance, surveillance, and/or test procedures dcscribcd and/or the bases for not including thc operational features cited.The opening of one PORV at power is bounded by the analysis in section 15.6 of the UFSAR.The Off-Normal Operating Procedure provides the operator with guidance for loss of one safety-related DC bus.R-8.b Instead of dcvcloping

&supplying thc information in response to Question 9, FPL may commit to further cvaluatc thc need for such provisions during the pcrformancc of the IPE for severe accident vulncrabilitics.