ML20085J959
| ML20085J959 | |
| Person / Time | |
|---|---|
| Site: | Brunswick  |
| Issue date: | 10/22/1991 |
| From: | Vaughn G CAROLINA 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, NLS-91-270, NUDOCS 9110300025 | |
| Download: ML20085J959 (22) | |
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.4 4 Carolina Power & Light Company P.O Don 1$51 e flaleigh, N C 27602 OCT 2 21991 SERIAL; NLS 2 70 G. E. VAUGHN V6ce President Nuclear Services Department United States Nuclear Regulatory Commission ATTENTION: Document Control Desk Washington, DC 20555 BRUNSWICK STEAM ELECTRIC PLANT, UNIT NOS. 1 AND 2 DOCKET NOS. 50-325 & 50-324/ LICENSE NOS. DPR-71 & DPR-62 RESPONSE TO CENERIC LETTER 91-06 ADEQUACY OF SAFETY RELATED DC POWER SUPPLTES Centlemen:
The purpose of this letter is to submit ':arolina Power & Light Company's response to NRC Generic Letter 91 06, " Resolution of Generic Issue A-30,
' Adequacy of Safety Related DC Power Supplies', Pursuant to 10 CFR 50.54(f)"
for the brunswick Steam Electric Plant, Units 1 and 2. The Staff requested written responses to questions provided in Enclosure 1 of the generic letter within 180 days of the date of the generic letter, which was issued on April 29, 1991.
Enclosed are Carolina Power & Light company's responses for the Brunswick Steam Electric Plant to the NRC questions contained in Generic Lettec 91-06.
Please refer any questions regarding this submittal to Mr. W. R. Murray at (919) 546-4661.
Yours very truly,,
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G. E. Vaughn WRM/wrn ( g191 - 06.wp f)
Enclosure cc: Mr. S. D. Ebneter M r . N . B . Le Mr. R. L. Prevatte l
,ph i 9110300025 91i022 PDR ADOCK 05000324 P PDR s g\
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Document Control Desk '
NLS 91 270 / Page 2 )
G. E Vaughn, having been firse duly sworn, did depose and say that the infor-mation contained herein is true and correct to the best of his information, knowledge and bolief; and the sources of his infocmation are c,fficers, employees, contractors, and agents of Carolina Power & Light Company, eau ccc >>JLdh,,si,nnu, d Notar cal)fg,/gOURY c; My commission expires: J (, f9 G, ; ,,, E
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ENCLOSURE 1 BRUNSWICK STEAM ELECTRIC PLANT, UNITS 1 AND 2 NRC DOCKET NOS, 50 325 6 50 324 OPERATING LICENSE NOS. DPR-71 & DPR 62 RESPONSE TO CENERIC LETTER 91-06 ADEQUACY OF SAFETY-RELATED DC POWER SUPPLIES Enclosed aro Carolina Power & Light Company's (CP&L) reeponses to the NRC questions contained in Ceneric Letter 91 06 for the-Brunswick Steam Electric- *
' Plant, Units 1 and 2. The-NRC questions have been repeated with the necessary ,
information provided in the blanks Icft by the NRC Staff. In addition, CP&L Lhas;provided comments and clarifications to the NRC questions, where
-appropriate.
NRC 00ESTION 1:
Unit 1
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'NRC 0UESTION 2:
The number of independent redundant divisions of Class IE or safety-
~
a.
related de power for this plant is two .- (Include any separate Class-1E'or safety-related de, such as any de dedicated to the dicsol generators.)
'b, .The number of functional safety-related divisions of de power necessary
~
to-attain safe shutdown for this unit-is ono , s j &L COMMENT AND CLARIFICATION:
OUESTION 2.a.
< Tho. Class 1E battery system for Udit 111s a 125/250 Vdc system. .The system is center tapped to provide 125 Vdc for circuit breaker control, relay -operation, ~ plant annunciation, emergency lighting, and un-interruptible 120.Vac power supplies. The -system air ivides 250 Vdc for de motors and'dc motor-operated. valves. There e- ovo divisions of
'125/250'Vdc batteries per unit and two units at the Brunswick Nuclear Project (BNP).
- 0UESTION 2,h.
The division I 125/250 Vdc batteries provide. power to the equipment
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necessary to operate the llPCI system valves and relay logic. The division I batteriee provido power to the divistor ' safety-related rwitchgear'and unit substations for breaker contr( In addition, the El 1 L
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division I batteries provide control pouer for the division 1 emert,ency diesel generator for Unit 1.
The division II 125/230 Vdc batteries provido power to the equipment necessary to operate the RCIC system vain &.A and relay logic. The :.
division 11 batteries provide power to the division 11 safety related E switchgear and unit substations for breaker control. In addition, the '.
division II batteries provide control power for the division II ,,
emergency diesel generator for Unit 1. ,
4 The 125/250 VDC bettery system at BNp is composed of four independent
'. 50 VDC batteries (eight ' ?S VDC batteries). The batteries are divided into two l! visions, division I and 11 for Unit 1 and division I and 11 for Uni' 2. Each unit's batteriae is shared with the other unit, that is, th" init i ba'teries will supply normal nr alten: nato power to nome Unit 2 equipment and the Unit 2 batteries sit supply normal or alternatt power to some Unit 1 equipment.
Control power for the division I or 11 safety related switchgear, unit substations, emergency diesel generators, and ESS panels can be transferred to the opposite unit division I or II, respectively.
ERC OUEST10N 3:
Does the control room at this unit have the following separate, independently annunciated alarms and indications for cech division of de power?
- a. alarms
. battery 61sconnect cr c9rcuit breaker open? _No
- 2. Battery charger disconnect or circuit breaker open (both input ac _
r.nd output de)? No
- 3. de system ground? Yss
- 4. de bus unde.rvoltage? _ yen 5 de bus overvoltage? Yes
- 6. Battery charger failure? _,Ynn
- 7. Battery discharge? Yes
- b. Indications 1 Battery float charge current? No
- 2. Battecy circuit output current? No, o
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- 3. Battery discharge? .jlm
- 4. Bus voltage? ..Yes.
- c. boes the unit have written procedures for response to the above alarms
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and-indications? D CP&L COMMENTS AND CIARIFICATIONS:
OUESTION 3.a.1.
Operating Instruction 01 3.4 Daily Check Sheets, require a plant auxiliary operator to verify that the battery output breaker is closed ;
once per 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period. This verification is asde by the auxiliary i operator during normal rounds through the battery rooms. In addition, a i general check of the battery rooms is made once por shift. This check 1
-includes-a general verification that breakers are not tripped, j OUESTION-3;a.2.
Alarts indication is_p ~"ided to the control room by annunciator 1 UA 23 1 7, "250V Battery A t rvoltage", 1-UA 23 1 8, "250V Battery B Unde rvoltage" , 1 UA 23,. 7, "250V Battery A Charger Trouble, and 1 UA.
23-2 8, "250V Battery B Charger Trouble, if the input ac breaker is opened for the battery charger, QUESTION'3 311.
Alarm. indication is provided to-the control room by t9nunciator 1 UA 23- .!
3-7, "250V Bat:ery A~ Cround" and 1 UA 23 3 B, "250V Battery B Ground" if
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the de ground resistance is less than or equal to 33,500 Ohms. A1 115, .
125/250 Vde' System Ground correction cuidelines, is used by plane -
operations to detarnine correccive actions to be taken in rosponse to a de ground.-
QUEETiON 3.g 4 ;
- Alarm indication is ptovided to the enntrol room by annunciator
-1 UA 23-17. "250V Battiry A Undervoltage" and 1 UA 23-18, "250V i Battery B Undervoltage". These annunciators will provide control room alarms if th- battery vo1*atn drops to 12912.6 Vdc.
i QUESTION 3.t $_t Alarm indic tion is provided tm the control room by annunciator
. 1 VA 23 2-7, "250V Battety A Ctarger Trouble" and 1.UA 23 2 8, "250V-Battery.B Cha.'er Tredble"Lif tLe charger output de voltage reaches 145.0 1 0.5 Vds Tae battery chergers at BSEP have high voltage shutdown = boards s' BAT-liVS-1A 1-7%) 1, 1 BAT llVS-1A 2-743 2, 1 BAT-HVS-1B-l'/44-1, and:leBATeHVC-1B 2 744 2) which will trip the charger ac 16put breaker if the<de output rcaches 143.0 1 0.5 Vdc. The hirn voltate shutdown boards.should prevent the voltage reaching the
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145.0 1 0.5 Vdc high voltage alarm point, however, the high voltage shutdown boards will cause the above snnunciators to alarm.
00ESTION 3-a.6. i Alms indication of a battery charger failure in providt3 in the eu itrol toom by annunciator 1.UA 23 2 7, "250V battery A Charger Trouble",
1.UA 23 2 6, "2$0V Battery B charger Trouble", 1 UA 23 1 ',, "250V Bettery A Undervoltage", and 1 UA 2318, "2$0V Battery B Undervolt age".
The battery charger trouble alarm (s) will be received if: (a) The ;
charger input ac voltage is less than 102 Vac or (b) the charger oatput !
de-voltage exceeds 143.0 1 0.5 Vdc. The battery charger undervo1+, age alarm (s) will be received if: (a) the battery charger output de ioltage- l is less than 129 Vdc or (b) the charger output voltage excecda !
143.0 1 U 5 Vdc causing the ac input breaker to trip.
QUESTION 3.a.7.
Alarm indication is provided to the control room by annunc.Stor 1 UA 2317, "2$0V Battery A Undervoltage" and 1 UA 2318, *250V Battery B Undervoltage". These annunciators will provide control room alarms if the battery voltage drops to 129 i 2.6 Vde, 1he annunciators 3 would alarm anytime a battery charger is removed froe the de bus and tho ;
- battery is carrying system loads.
QUESTION 3.b.1. ,
i Local float chkrge current meters are provided on the battery chargers, which provide an indication of tc'al charger output current (i.e., load current plus battery float curren,). ilowever, there are no current meters in the control room.
i OUFSTION 3.b.t. .
Local current meters are provided on the battery charger and provido an !
indication of-battery charger output current. The current meters do not provide an indication of the battery output current. ,
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' 00ESTION 3.b.3.
Local battery oltage mete *. 1 BAT-VM 6009 (Battery 1A 1), 1 HAT VM 6010' 5 (Battery 1A 2), 1 BAT VM 6011 (Battery 1B-1), and 1 BAT VM-6012 (Battery _1B 2) provide indication of the battery voltage during
- discharge. Control room indication-of battery discharge voltage is '
- provided.by voltage meters 1. BAT VM 737 (Battery 1A 1), 1 BAT VM 738
- (Battery 1A 2), 1-BAT-VM 739 (Battery 1B lb and 1 BAT-VM 740 t (Pattery.1B 2), In addition,' battery bua voltcge indication is provided -
. by .the ERFIS ' computer system by ERFIS points 1 ED_VA007,1-ED_VA008, 1 ED_,VA009, and 1.ED_VA010. All voltage metere and ERFIS points will
- provide an indication of battery discharge vol: age when the battery L chargers are not in service (i.e. , charger failure, ac input breaker t
open, etc.).
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. 1 OVESTION 3.b.4. ,
i Control room indication of de bus voltage is provided by voltage meters !
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1 BAT VM 737 (Battery 1A 1), 1+ BAT VM 738 (Battery 1A 2), 1 BAT VM.739 (Battery 1B.1) and 1 BAT VM 740 (Battery 1B 2). These voltage meters ;
will provide an indication of battery charger or battery bus voltage. !
Battery bus voltage indication will be provided if the battery charger
's not operating and the battery charger output DC breaket is not open. '
EeTIS computer points 1 ED_VA007,1 ED_VA008,1 ED_VA009, and 1 ED VA010 ,
wil? provide control room indication of the battery bus voltage t rega 41ess of the position of the battery or charger output breakers.
In ado,* tion to the above indicators and computer points, local voltage ,
meters *?e orovided at the battery chargers. The local voltage meters !
will only orovice en indication of bus voltage if the battery charger output brenNer is closed.
I
-QUESTION 31c.
Annunciator proces'ures aro written for response to alarms. Indications are used to validtts the annunciator alarms as per the annunciator procedures. t Administrative Instruction AI 115,125/250 Vdc System Cround Correction Cuidelines, is used for response to de system grounds. .)
NRC OUESTION 4:
Does this. unit have indication of bypassed and inoperable statur of circuit l breakers or other devices that can be used to disconnect the battery and i battery charger from its de bus and the battery charger from its ac power source during maintenance o testing? No i
. LP&L COHMENTS AND CLARIFICATIONS:- {
' nae c'sarance procedure Al-58, Equipment Cir.arance Procedure, Revision
=34 and.the LCO requirements far the 125/2'J Vdc batteries ensure that "
maintenance and testing activities are r ntrolled e and that the control
- room is aware of the status of all byrassed and !.noperable circuit breakers or other devices which can disconnect;a battery or battery charger. See response to questier,6.
NRC OUESTTON_.5:
If the ansvar to any part of question 3 or 4 is no, then provide information
. justifying the- existin6 deSi8n features'of the facility's safety related Je I
systems.-
- See note below.
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[f1L_[0MMENTS AND CIARlFICATIONS:
See justification for each question arwered "No" in the Question Comment and Clarification section of this response.
EQ_Q1)fSIl05.J:
(1) llave you conducted a review of maintenance and testing activities to minimir.e the potential for human error causing more than one de division to be unavailable? ..Yes and (2) do plant procedures prohibit maintenance or testing or redundant de divisiens at the same time? Yes CP6L COMMENT AND C1ARIFICATION:
A review of maintenance and testing activities was conducted as part of the plant's review of Bulletin 79 27 " Loss of Non Class 1E Instrumentation and Contrcl Power System Bus During Operation",
completed February 26, 1980 and Information Notice 85 74, " Station Battery Problems", completed October 17, 1985. A number of procedure changes were made based upon the results of the reviews. BNP batteries are maintained in accordatce with the guidelines of IEEE Standard 0$0 1980, even though the Brunswick Plant is not committed to the standard.
In order to take a battery and/or battery charger out of service, a clearance must be genereted for the equipment. AI 58," Equipment Clearance Procedure" provides the guidance for obtaining an equipment clearance. Per AI $8, the following actions must be completed prior to hanging the equipment cicarance:
(a) The cicarance requestor must obtain Site Work Force Control Group (SWFCG) or Planning and Scheduling review of the clearance.
This review checks the clearance against other activities, in progrena or scheduled, which may impact the clearance.
(b) The Clearance Control Center Staff reviews and prepares the clearanco. This review and preparatica is performed by two independent licensed operators one of which must be a Senior Reactor Operator.
(c) The approval of the clearance must be performed by two independent licensed operators one of which must be an SRO. The approval of the cicarance specifically looks for Technical Specification or ESF system involvement.
(d) Upon approval of the clearance, the inoperabic equipment is tracked by a computer based LCO tracking system. The LCO conditions are reviewed every shift by the duty SR0s.
(e) When the clearance is hung it is double verified by auxiliary operators.
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l The clearance procedure and subsequent actions preclude maintenance or j testing on redundant de divisions at the same time.
i If the facility Technical Spectiications have provisions equivalent to those found in the Westinr, house and Combusition Engiileering Standard 'lechnical Specifications for maintenance and surveillance, then question 7 may be skipped and a statement to the effect may be inserted here. Equivalent to Westinr. house Standard Technical Specifications except as specifically addressed in t.ho Question Comments and Clarifications section of this ,
Insponne.
EEG OUESTION Z:
Are maintenance, surveillance and test procedures-regarding station batteries 3 eonducted routinely at this plant? Specifically: ,
- a. At least onco per 7 days are the following verified to be within ,
acceptable limits:
- 1. pilot ce11' electrolyte icvel? : Yen
- 2. Specific gravity or charging current? Yes .f
- 3. Float voltage? Yes
- 4. . Total bus voltage on float charge? Yes '
- 5. Physical condition of all cells? Yes
- b. At least once per 92 days, or within 7 days after a battery discharge,- ,
e overchar6e, or if-the pilot cell readings are outside the 7 day surveillance requirements are the following verliied to be within acceptance limits:
- 1. C'ectrolyte level of each cell? "!c s I
- 2. Tiie average specific gravity of all cells? , ley _,
- 3. The specific gravity of each cell? Yes
- 4. The average-electrolyte temperature _of a representative number of l~ cells? Yes I
L 5. The. float voltage of each cell?- Yes
- 6. Visually inspecc or measure resistanco of terminals and connectors '
(including-the connectors at the de bus)? Yes
- c. At least-every 18 months are the following verified:
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- 1. Low .usistance of each connection (by test)? Yes
- 2. Physical condition of the battery? ___Yes
- 3. Battery charger capability to deliver rated ampere output to the de bus? Yes l
- 4. The capability of the battery to deliver its desi n6 duty cycle to the de bus? .Yes_ F
- 5. Each individual cell voltage is within acceptable limits during the service test? ,_Yes
- d. At least overy 60 months, is capacity of each battery verified by performance of a discharge test? Yes
- a. At least annually, is the. battery capacity verified by performance discharge test, if the battery shows signs of degradation or han reached :
85% of the expected service life? Yes CP&L COHMENTS AND CIARIFICATIONS:
~0CESTION 7 In addition to the Technical Specification required _ weekly, quarterly, semi annually, and five year battery checks, BNP batteries are checked once per month per procedure IMST BATT11M to verify acceptability of the ,
following: overall voltage, pilot cell voltage, pilot cell elect olyto level' pilot cell specific gravity, pilot cell temperature, individual cell electrolyte level, and individual cell voltage. If any values are not_within Technical Specification allowed vclues, then the appropriate portion of the once por 92 dev *echnical Specification surveillance is
-performed.
OUESTION 7.a.2.7.a.3 Pilot cell specific gravity and float voltage are verified every seven day s , .
QUES 7 ION 7.b.
Plant Technical Specifications do not specifically require verification of electrolyte level, average specific gravity, individual cell specific gravity, average temperature, float voltage, or terminal resistance following a battery discharge or overcharge.
l' OUESTION 7.b.6 L
l Bus connections at the battery are checked; however, bus connections at
! the DC switchboard are not checked overy 92 days.
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__ _ _ _ _._ . __ _ __ __ , - . _ . _ _ . _ _ _ m QUESTION 7.c.3.
A Propel High Rate Discharge (llRD) tester is used to test the battery charger capability to deliver rated ampere output. Test current is delivered to the llRD tester via the de bus. Total test current is established as a combination of de system loads and high rate discharge tester loads.
QUESTION 7.e.4.
A Propel llRD tester is used to test the battery capability to deliver its designed duty cycle, therefore, test current is delivered to the llRD tester during testing not to the de bus.
OUESTION 7.c.5-Individual cell voltages are taken at the ho61nning of the service test.
QyES310) 7. e .
Plant Technical Specifications do not require verification of the battery capacity annually when batteries show signs'of degradation or have reached 85% of the expected service life. BNp has made 1NPO commitments to replace the batteries within 1 year.or to test the batteries annually if degradation is observed or 85% of service. life is reached. This requirement has been incorporated into plant Technical Specification required performance discharge test procedures. BNP Unit .1 and 2 batteries have reached 85% of the expected service life.
The Company has decided to replace the batteries in lieu of annual testing. The Unit 1 batteries are scheduled for replacement during the Roload 8 outage currently scheduled to begin September 12, 1992.
NRC OUESTION 8:
Does this plant have operational features such that following loss of one safety related de power supply or bus:
- a. Capatility is_ maintained for ensuring continued and adequate reactor cooling? _yes
- b. Resctor coolant system integgity and isolation capability are -
mainteined? Yes
- c. -Operating procedures, instrumentation (including indicators and annunciators), and control functions are adequate to initiate systems
! required to maintain adequate core coolittg? Yes L
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FP6L COMMENTS AND CIAR1FICATIONS: l None. [
E OUESTION 9:-
If the answer to eny part of question 6, 7. or 8 is no, then provide your I basis for not performing the maintenance, surveillance and test procedures 6 described and/or the bases for not including the operationni features cited, f ASee note below. i
- NOTE: For questions involving suppor;.ing type inform . ton (question numbers'5 and 9) instead of developing and supplying the information in response to this lettir, you may commit to further :
evaluate the need for such provisions during tr.o performance of your individual plant examination for sev_ ore accident
-vulnerabilities (IPE), If you select this option, you are required to:
(1) So state in response to these questions, and (2) _ Commit to explicitly address questions 5 and 9 in your IPE :
submittal per the-guidelines outlined in NUREG 1335 ,
(Section 2.1.6, Subitem 7), " Individual Plant Examination: i
. Submittal. Guidance." _,
CP6L CQg9:TS AND CIARIVICATIONS:
None.
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ERC OUEST10N 1:
Unit 2 EBC OUEST10N 2:
- a. The number of independent redundact divisfuns of Class 1E or safety-related de power for thic plant. is two . (include any separate Class 1E or safety related de, such as any de dedicated to the diesel generators.)
- b. The number of functional safety related divisions of de power necessary to attain safe shatdown for this unit is _sne .
CPf,L CQOENT.. AND CIARIFILQLQN:
OUEST10N '.a.
The Class 1C battery syrtem for Unit 2 is a 125/250 Vdc system. The system is center tapped to provide 125 Vdc for circuit breake; control, relay operation, plant annunciation, emergency lighting, and un-interruptible 120 Vac power suppilos. The system also providew 250 Vdc for de motora and de notor operated valves. There are two divisions of 125/250 Vdc batteries per unit and two units at the Brunselck Nuc1 cat Proj ec t (BNP).
Q1L ESITON 2.ba The division I 125/250 Vdc batteries providu powec to the equipment necessary to operate the llPCI system valves and relay logic. The division I batteries provide power to the division I safety-relat ed switchgonc and unit substations for breaker control. In addition, the division I batteries provido control power for the division I emergency diesel generator for Unit 2.
The division 11 125/250 Vdc batteries provide power to the equipment necessary to operate the RCIC system valves and relay logic. The division 11 batteries provido power to the division Il safety related switchgear and unit substations for breaker control. In addition, the division 11 batteries provide control power for the divialon Il emergency diesel generator for Unit 2.
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The 125/250 VDC battery system at BNP is composed of four independent 250 VDC batteries (eight 125 VDC batteries). The batteries are divided
- into two divisions, division I and 11 for Unit 1 and division I and 11 for Unit 2. Each unit's batteries is snared with the other unit, that is, the Unit 1 batteries will supply normal or alternate power to some Unit 2 equipwent and the Unit 2 batteries will supply normal or alternate power to some Unit 1 equipment.
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Control power for the division I or II safety related switchgear, unit substations, emergency diesel-generators, and ESS panels can be j transferred to the cpposite unit division I or II, respectively. l I
i NRC OUESTION 3:-
Does the control room at this unit have the following separate, independently annunciated alarms and indications for each division of de power?
- a. alarms
- 1. Battery disconnect or circuit breaker open? No
- 2. Battery charger disconnect or circuit breaker open (both input ac and output de)? No i l
3.- de system. ground? Yes.
- 4. de bus undervoltage? Yes l l
5.. de bus overvoltage? Yes
- 6. Battery charger failure? Yes ;
- 7. Battery discharge? _191_
b.. Indications
- 1. Battery float charge current? .-Po ,
- 2. Battery circuit output current?- No
- 3. Battery' discharge? Yes 4 - Bus voltage? Yes.
- c. Doas the unit ~have written procedares for response to the above alares 1 and-indications? Yes CP&L COMMENTS AND CIARIFIQATIONS *- ;
OUESTION 3.a;1.
Operating Instruction 01-3.4, Daily Check Sheets, require a plant' .
aux 111ary operator to verify that the battery output breaker is closed once per 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period. Th.is verification is made by-the auxiliary Loperator'during normal roundsLthr; ugh the battery rooms. In addition, a general check of the battery rooms _is made once per shift. This check includes a general verification that breakers are not tripped.
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OUESTION 3.a.2.
Alarm indication is provided to the control room by anrunciator 2.UA 23 17, "250V Battnry A UndervoltaSe". 2 UA 23-1-8, "250V Battery B Undervoltage", 2.UA 23 2 7, "250V Battery A Charger Trouble, and 2 UA. i 23 2 8, "250V Battery B charger Trouble, if the input ac breakcr is ,
opened for the battery charger. l OUESTION 3.a.3.
Alarm indication is provided to the control room by annunciator 2 UA 23 3-7, "250V Battery A Cround" and 2 UA 23 3 8, "250V Psttery B Ground" if ,
the de ground resistance is less then or equal to 33,500 Ohms. AI 113, l 125/250 Vdc System Cround Correction cuidelines, is used by plant l
- operations to determine corrective actions to be taken in response to a j de ground. i i
OUEST10N 3.a.4.
Alarm indication is provided to the control room by_ annunciator 2-UA 23 1 7, "250V Battery A Undervoltage" and 2 UA 23-1 8, "250V Battery B UndervoltaSo". These annunciators will provide control room alarms if the battery voltage drops to 129 1 2.6 Vdc.
OUEST10N 3.a.). :
Alarm indiuation is provided to the control room by annunciator 2 UA 23-2-7, "250V Battery A Charger Trouble" and 2-UA 23 2-8, "250V Battery B Charger Troublo" if the charger output de voltage reaches
-145.0 1 0.5 Vdc. The battery chargers at BSEP have high voltage i shutdown boards (2 BAT HVS 2A 1-743-1, 2 BAT.HVS 2A 2 743-2, 2 BAT HVS 23 1 744 1, and 2 BAT.HVS-2B 2-744 2) which will trip the cher6er ac input breaker if the de output reaches 143.0 i 0.5 Vdc. the
- high voltago shutdown boards should prevent the voltago reaching the 145.0 i 0.5 Vdc high voltage alarm point, however, the high voltage shutdown boards will cause the above annunciators to alarm.
QUESTION 3.a.6 6 Alarm indication of a battery charger failure is provided in the control room by annunciator 2-UA 23 2 7, "250V Eattery A Charger Trouble",
2 UA 23 2 8,' "250V_ 'lattery B Charger Trouble", 2-UA 23 1 7, "250V Battery A Undervolts6e", and 2 UA 23 1 8, "250V Battery B Undervoltage".
The battery charger' trouble alarm (s) will be received if: (a) The charger input ac vol age is less than 102 Vac or (b) the charger output .
de voltage exceeds 143.0 i 0.5 Vic. The battery charger undervoltago alarm (s) will.be rec aived if: (a) the battery charger output de voltage is less than 129 Vdc or- (b) the charger output voltage exceeds
. 143.0 1 0.5 Vdc causin6 the ac input breaker to trip.
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,r QUESTION 3.n.7 Alarta indication is provided to the control room by annunciator i 2 UA 23 1 7, "250V Battery A Undervoltago" Gud 2 UA 23 1 8, *250V i Battery B Undervoltage", Those annunciators will provide control room alarms if the battery voltage drops to 120 1 2.6 Vdc. The annunciators would alarm anytime e battery ch. ger is removed from the de bus and the battery is carrying system loads. '
OUESTION 3.b.1.
Local float charge current meters are provided on the battery chargers, which provido an indication of total charger current (i.e., load current plus battery float current ), llowever, there are no current meters in the control room.
QUESTION 3.b.2.
I.ocal current roeters are provided on the battery charger and provido an indication of battery charger output current. The curror.t motors do not provido an indicattore of the battery output current.
QUESTION 3.b.3.
Local battery voltage maters 2 BAT VM 6009 (Battery 2A-1), 2 BAT VM 6010 !
(Battery 2A 2); 2 BAT VM 6011-(Battery 28 1), and 2 BAT VM 6012 ;
(Battery 2Be2) provido indication of tho battery voltage during discharge, Control room indication of battery discharge voltage is provided by voltage metets 2 BAT VM-737 (Battery 2A 1), 2 BAT.VM 738 ,'
'(Battery 2A 2),~2 BAT 4VMe739 (Battery 2B 1) and 2 BAT VM 740 (Battery 2B 2). In addition, battery bus voltage indication is provided ,
by the ER/IS.computa syctem by ERFIS points 2 EQ,VA007, 2 ED,,,VA008, 2 ED_VA009, and 2'ED_VA010. All_voltago meters and ERFIS points will provide an-indicatica of battery discharge voltago whnn the battery chargers are not in service (i.e., charger failure, se input breaker ;
open, etc.).- :
OUEST10N 3.b.4, i Control room indication of de bus voltago la provided by voltago meter 9 2 BAT VH 737 (Battery 2A 1), 2 BAT VM 738 (Battery 2A 2), 2 BAT VM 759 (Battery 2B 1) and 2 BAT VM 740 (Battery 28 2). Thoee voltage motors will provido an indication of battery charger or battery bus voltage.
Battery bus voltage indication will be provided if the battery charger Lis not operating and=the battery chargar. output DC breaker is not open..
- ERFIS computer points *2 ED_YA007 2 ED_VA008, 2-ED_VA009, and 2 ED_VA010.
will provide control room indication of the battery bus voltage regardicas of the position of the battery or. charger output breakers;- ,
In addition to the above indicators and computer points, local voltage ,
meters are provided at the battery chargers. 4ho local voltago meters will only provide an indication of bus voltage if the battery charger
- output breaker is closed.
El 14
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OUESTION 3.'c.
At_nunciator procedures are written for response to alarm 6. Indications l are used to validate the annunciator alarms as per the annuncistor ,
procedures, !
Administrative Instruction AI 11$, l ,250 Vdc System Cround Correction l Cuideltnes, is used for response to c. syetem grounds.
NRC 00EST10N_s: ,
Does this unit have indication of bypasned and inoperatic status of circuit breakers or other devices that can be used to disconnect the battery and battery charger from its de bus and the battery charger from its ac po.vr source durin6 maintenance or test!ng? No CP&L C0!MENTS AND CIARIFIC61]gM:
The clearance procedure Al 58,-Equipment Clearar.co Procedure, Revisioti 34' and the LCO requirements for the 125/250 Vdc batteries ensure that maintenance and testing activities are controlled and that the control room icjavare of tho; status of all bypassed and inoportble circuit .
. breakers or other devices which can disconnect a battery or battery
< charger. See rc6ponse to question 6. .
L@S_ QUESTION 5:
If the answer to any part of question 3 or 4 is no, then provide information !
r jestifyin5'the exis 1 ag design features of the facility's safety related de systems.
- See nots below.
CP6L COMMENTS AND CIARIFICATIONS:
See justificacion for each question answered "No"- in 'the Question Comment and Clarification section of this response.
}
NRC OUESTION 6: ;
(1) llave you conducted a review of maintenance and resting activities to minimize the potential for human error causin6 more than ona de division to be unavailable? _1gp_ and (2) do plant procedures prohibit maintenance or testing on redundant de divisions at the same time? Yes -
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4 y CP6L COMMENT AND CIARIFICATIOW; A review of maintenance and testing activities was conducted as part of the plant's review of Bulletin 79 27 " Loss of Non Cla=s 1E Instrumentation and Control l'ower System Bus During Operation",
completed February 26, 1980 and Information Notice 85 74, " Station -
Battery Probicas", completed October 17, 1985. A number of procedure changes were made based upon the results of the reviews. BNP batteries are maintained in accordance with the guidelines of IEEE Standard 450 1980, even though the Brunswick Plant is not coiwaltted to the standard, i
i In order to take a battery and/or battery charger out of service 4 alearance must be generated for the equipment. AI 58," Equipment -!
Clearanco Procedure" provides the guidaneo for obtaining an equipment
- clearance. Per A1 58, the following actions must be completed prior to hanging the equipment clearance:
- (a) Th6 clearance requestor must obtain Sire Work Force Control Group (SWFCG) or Planning and Scheduling review of the clearance.
This review checks the clearance against other acti.vities, in progressLor scheduled, which may impact the clearance.
(b) The Clearance Control Center Staff reviews and prepares the clearance. This review and preparation is parformed by two independent licensed operators one of which must be a Senior Reactor Operator. _
(c) The approval of the clearance must be performed by two independent i licensed operators one of which must be an SRO. The approval of the cicarance specifically looks for Technical Specification or ESF system involvement.
(d) .Upon approval of the clearance, the inoperable equipment is '
cracked by a computer based LCO tracking system. The open LCO conditionr aro reviewed overy shift by the duty SR0s.
(e)- When thn clearance is hung it is double verified by auxiliary operators.
_The' clearance proceduro and subsequent actions preclude maintenance or <
testing on redundant de divisions at_the same time. !
If the facility Technical Specifications have provisions equivalent to those found in the Westinghouse and Combustien Engineering Standerd Technical >
Specifications for maintenance and surveillance, then question 7 may be
-skipped andLa statement to the effect may be inserted here. Equivalent to ,
Westinnhouse Stanoard Technten1 Specifications exccot as specifically
- addressed in the Ouestion_Qomments and Clarifications soglion of this regponse.
EBS_ QUESTION 7:
. Are maintenance. survotilance and test procedures regarding station batteries conducted' routinely at thi.s plant? Specifically:
E1 16
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- a. At least once per 7 days are the following verified to be within acceptable limits:
- 1. Pilot cell electrolyte level? Yen
- 2. Specific gravity or charging current? _1gg_
- 3. Float voltage? ..Yes_ l l
- 4. Total bus voltage on float charge? _Ygg_ ;
-J
- 5. Physical condition of all cells? _Xsa_ !
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- b. At Icaat once per 92 days, or within 7' days after a battery dischcrge.
overcharge, or.if the pilot cell readings are outside the_7 day surveillance requirements .re the following verified to be within acceptance limits:
- i I
- 1. ' Electrolyte level of each cell? _Yga_
2.- The average specific gravity of all cells? _Yga_
- 3. The specific gravity of each cell? Yes j
- 4. The average electrolyte temperature of a representative number of cells? Yes . t
- 5. The float volta 6e of each et117 _Xg.g_
- 6. Visually inspect or measure resistance of terminals and connectors (including the connectors at the de bus)? _Jfut,
- c. At least.every 18 months are the following verified:
r ,
- 1. - Low resistance of each connection (by test)? Yeg_
- 2. Physical condition of.the battery? _Yes
-3.- - Battery charger capability to deliver rated ampere output to the de bus? Yes a
- 4. -The capability of the battery to deliver its' design duty cycle to the~de bus? ,,yes 5, Each individual cell voltage is within acceptable limits during the service test? Yos-li l' At least every 60-months, is ' capacity of each battery verified by
~
d.
fperformance of a discharge test? _ygg_
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- c. .At least annually, is the battery capacity verified by performance i discharge test, if the battery shows signs of degradation or has reached 85% of the expected service 11fe7 ,,1ta_
Cfhh_QQMMENTS AND- CLARIFICATIONS: ;
OVESTION 7 in addition to the Technical Specification required weekly, quarterly, semi annually, and five year battery checks, BNP batteries are checked once per month por procedure 2HST BATT11H to verify acceptability of the i following: overall voltage, pilot cell voltage, pilot cell electrolyte level, pilot cell specific gravity, pilot cell temperature, individual cell electrolyte icvol, and individual ec11 voltage. If any values are ,
not within Technical Specification allowed values, then the appropriate portion of the once per 92 day Technical Specification surveillaneo is ;
performed.
OUESTION 7.a.2.7.a 3 ;
Pilot cell specific gravity and float voltage are verified every seven days.
QUESTION 7.b.
Plant Technical Spncifications do not specifically require verification of electrolyte level, average specific gravity, individual ec11 specific gravity, average temperature, float voltage, or terminal resistance following a battery dischar6e or overcharge.
QQE1110N 7.b.6 Bus connections at the battery are checked; however, bus connections at '
the DC switchboard are not checked every 92 days.
QUESTION 7.c.3. -
A Propel lligh Rate Discharge (llRD) tester is used to test the battery charger capability to deliver rated ampero output. Test current is delivered to the llRD tester via the de bus. Total tose current is ,
established as a combination of de system loads and hi h8 rato dischar6er tester loads.
OUEST10N 7.c.4.
A Propel itRD' tester is used to test the battery capability to deliver its desi 6ned daty cycle, therefo:c, test current is deliveired to the llRD
!- tester during testing not to the de bus, El 18 L
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OUESTION 7,e d Individual cell voltages are taken at the beginning of the service test.
QUESTION 7,fa Plant Technical Specifications do not require verification of the battery capacity annually when batteries show signs of degradation or have reached 85% of the expected service life. BNP has made INPO commitments to replace the batteries within 1 year or to test the batteries annually if degradstion :: observed ot 85% of service life is reached. This requirement has been incorporated into plant Technical Specification required performance discharge test procedures. BNP Unit 1 and 2 batteries have reached 85% of the expected service lifc.
'Ihe Company has decided to replace the batteries in lieu of annuni testing. The Unit 2 batteries are scheduled for replacement during the Reload 9 nutage currently in progress.
NRC OUfiSJJQ!1,R,:
Does this plant have operational roatu~es such that fo'lo"ing loss of one safety related de power capply or bus:
- a. Capability is maintained for ensuring continued and adequate reactor cooling? Ye m._
- b. Reactor ceolant system integrity and isolatican eq. ability are maintained? ,,Jcg,_
- c. Operating procedures, instrumentation (,acluding indicators and annunciators), and control functions are adequate to initiate systems required to maintain adequato core cooling? .le.;L.
CPM, COMMENTS /.ND CLARIFICATIONS:
None.
NRC OUEST10N 9:
If the answar to any part of question 6, 7, or 8 is no, then provide your basis for not performing the maintenance, surveillance and test procedures described and/or tha bases for not including the operational features cited.
- See note belov.
- NOTE: For questicas involving supporting type information (question numbers 5 and 9) instead of developing and supplying the information in response to thi.e letter, you may commit to further evaluate the need for such provisions during the performance of El 19
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,7 your individual plant examination for severe accident vultierabilities (IPE). If you selc:t this option, you are required to:
(1) Se ctats in response to these questions, and (2) Commit to explicitly address questions 5 and 9 in your IPE submittal per the t,uidelines outlined in NUREG 1335 1
(Section 2.1.6, Subitem 7), " Individual Plant Exainination: ,
Subtaittal Guidance. " l 1
CP&L COMMENTS AND CU.RIPTCATIONS: l 4/ None. '
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