ELV-03106, Forwards Response to Generic Ltr 91-06, Resolution of Generic Issue A-30, 'Adequacy of Safety-Related DC Power Supplies.'
| ML20085J714 | |
| Person / Time | |
|---|---|
| Site: | Vogtle  |
| Issue date: | 10/22/1991 |
| From: | Mccoy C GEORGIA POWER CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| REF-GTECI-A-30, REF-GTECI-EL, TASK-A-30, TASK-OR ELV-03106, ELV-3106, GL-91-06, GL-91-6, NUDOCS 9110290316 | |
| Download: ML20085J714 (20) | |
Text
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$;; ,';j " ' ' ' " vamen. ? , u w, October 22, 1991 ELV-03106 000738 Docket Nos. 50-424 50-425 U. S. Nuclear Regulatory commission ATTN: Document Control Desk Washington, D. C. 20555 Gentlemen:
V0GTLE ELECTRIC GENERATING PLAN 1 RLSf0]NJLJ,0J[.NER1C LE1iER 91-06 The information requested by 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 Plant Vogtle Units 1 and 2 is provided in the Onclosures to this letter. The responses to the questions for Unitt I and 2 are presented in Enclosures 1 and 2, respectively.
Mr. C. K. McCoy states that he is Vice President of Georgia Power Company and is authorized to execute this oath on behalf of Georgia Power Company, and to the best of his knowledge and belief, the facts set forth in this letter and the enclosures are true.
GEORGIA POWER COMPANY By:
C K. McCoy '~~
Sworn to and subscribed before me this cG* day of _Qc ch 1991.
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Enclosures:
c: Gtprgia Poter_f.cm.p_An.L Mr. W. B. Shipman Mr. M. Sheibant fl0RMS LL L._IlEle B.r__Reaultt9 LLC 0mm i s s i c ru Mr. S. D. Ebneter, Regional Administrator Mr. D. S. Hood, Licensing Project Manager, NRR Mr. B. R. Donser, Senior Resident inspector, Vogtle l
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ENCLOSURE 1 V0GTLE ELECTRIC GENERATING PLANT - UNIT 1 lli[QBMTION REQUESTED _l4 GENERIC LETIIJL9h06 Question 1:
Unit?
Response:-
Unit 1.
Question 2:
A. The number of independent redundant divisions of Class lE or safety-related DC power for this plant is (include any separate Class lE or safety-related 00, such as any DC dedicated to the diesel generators.)
B. The number of functional safety-related divisions of DC power necessary to attain safe shutdown for this unit is. '
Response
A. Two.
B. One.
Question 3:
Does the control room at this unit have the following separate, independently annunciated alarms and indications for each division of DC power?
^
A. Alarms
- 1. Battery disconnect or circuit breaker open?
- 3. DC system ground?
- 4. DC bus undervol hge?
l 5. DC bus overvoltage? !
- 6. Battery charger failure?
- 7. Battery discharge?
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ENCLOSURE 1 (CONTINVED)
V0 GILE ELEC1RIC C[l4[RAllf4G PLANT - Viill 1 ItLTRf14110!LRLOVLS.II(LDL DIRLEILLLittfL9hM B. Indications
- 1. Battery float charge current?
- 2. Battery circuit output current?
- 3. Battery discharge?
- 4. Bus voltage?
C Does the unit have written procedures for response to the above alarms and indications?
Response: (See explanation regarding sharing of annunciator windows and justification for negative answers to questions 3.A.5, 3.A.7, 3.B.1, and
?.B.3 under the response to question 5.)
A. Alarms
- 1. Yes.
i
- 2. Yes.
- 3. Yes.
- 4. Yes.
- 5. No.
- 6. Yes.
- 7. No.
i . Indic l' ions
- 1. No.
- 2. Yes.
- 3. No.
- 4. Yes.
C. Yen.
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.h .. I ENCLOSURE I (CONTINUED)
VDGTLE ELECTRIC GENERAllNG PLANT - UNIT 1 MQBMATION RLQV[STED INJENERIC LETTER 91-Qs Question 4:
Does this unit have indication of bypassed and inoperable status of circuit breakers or other devices that can be used to disconnect the battery and battery charger from its DC bus and the battery charger from its AC power source during maintenance or testing?
Response
Yes. A loss of either the charger DC output or the AC input to the .
charger will be alarmed in the control room. if the MCC feeder breaker to the charger, the charger AC input breaker, the charger DC output breaker, or the DC switchgear breaker are opened, a battery charger trouble alarm will occur due to a loss of charger input, a charger AC input breaker o en l and/or a loss of charger output (no-charge alarm). There is an alarm taat will sound in the control room when the circuit breaker that connects the battery to the DC switchgear is opened, this alarm clears when the breaker is racked out. However, if the breaker is racked out for maintenance or testing the control room shift supervisor must sign off on the clearance and tagging procedure before work commences. Therefore, the control room r operators will be aware of any battery or battery charger that is made inoperable, in addition, there are local indicators that display the DC current and voltage, which would be identified by operators making routine equipment surveillances.
Question 5:
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..
Response
Exolanglion and Justification Relative to Question 3 L A "yes" response to an alarm (3.A) indicates that there it a separate, independently-annunciated alarm for the specific function in question. It l does not mean that the specific function has a dedicated tnnunciator window. Several alarm signals may be transmitted and paralleled to a l single annunciator window. As an example, Annunciator Window B04 for -
l annunciator light board-34 on the electrical auxiliary board panel " Bat Chargers IBDICA 18D108 Trouble" would illuminate, and an alarm would sound for the following conditions:
- 1. DC output overvoltage. '
l
- 2. AC input voltage low.
- 3. Loss of DC output.
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I ENCLOSURE 1 (CONTINUED)
V0GTLE ELECTRIC CENERATING PLANT - UNIT 1 INFORMATION RE0 VESTED IN.GDiERIC LETTER 91-06 ,
This annunciator would alert the operator to a problem associated with one !
of the battery chargers that feed battery IBDlB and switchgear 18D1. The !
specific problem would then be ascertained and corrected in accordance i with the appropriate annunciator response procedure. Since the functions are alarmed in the control room and any of the conditions that cause the annunciator to activate would be investigated and corrected, it is believed that the functions are adequately monitored, and a dedicated.
annunciator window for each alarm function is not necessary.
Questien 3.A.5 - There is no overvoltage alarm in the control room that !
specifically monitors the DC bus. However, high DC output voltage from the battery-charger would cause-the circuit breaker _in the charger input AC line-to trip, which would in turn cause a control room battery charger
. trouble alarm. There is also an alarm on high DC voltage to the 7.5-kVA inverters, one of which is fed from each of the DC switchgears. In addition, there is a system voltage indicator in the control room that would indicate an overvoltage condition. If the bus voltage was high, the inverter high DC voltage would alarm, and the control room inoicator would provide the operators the necessary information to. determine the problem.
The annunciator response procedures would also require 1:at an operator be dispatched to the affected area for further evaluation. Local instrumentation at the switchgear, battery chargers, inverters, or DC -
panels would confirm the specific problem.
-Question 3.A.7 - There is no control room alarm that specifically indicates'that'a battery is being discharged. Control room indication is provided for. battery current.and bus voltage. A discharging battery .
carrying a significant load would be detected by the control room indicators. A bus undervoltage alarm would be received in the control room long before the batteries are: discharged. Battery discharge can only-occur when the output of the battery charger cannot maintain the DC system voltage and current. There are two redundant battery chargers for each _ ,
bus and each is sized to maintain the bus at full-load steady state plus-maintain the battery at float voltage, i t would take the failure of both chargers or a fault on the bus to cause the battery to discharge.- Charger '
failure would be annunciated in the control room. Surveillance testing
.which would detect-a discharged condition is-performed on a 7-day interval .
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ENCLOSURE 1 (CONTINUED)
V0 Gill ELECTRIC GEllERATING PLANT - UNil 1 INf0RM110N REQVESilD llLMNERIC LETTER 91-Qi Question 3.B.1 - There is no indicator in the centrol room that is capable of indicating the battery float current. The battery output current and the system voltage are indicated in the control room. The battery output current would normally indicate zero on the indicator. If the battery charger should malfunction requiring the battery to feed the DC bus, the indicator in the control room would indicate the current flow. If for some reason the battery became discharged requiring a significant current flow from the charger to the battery, the ammeter would provide the magnitude of the current. If the proper float current is not maintained and the condition is not detected by the available monitoring instrumentation, it will be identified during the scheduled surveillance testing.
Question 3.B.3 - There is no control room ndicator that specifically displays a battery discharge condition, but the battery output current indicator would alert the operators if a battery was carrying a significant load or if a large current was required to maintain a battery in the charged condition. It is very unlikely that a battery could discharge without being detected by existing instrumentation. A battery could not discharge to the DC bus unless there was a problem with a battery charger. Any battery charger trouble that would cause a battery to discharge to the bus would be detected and alarmed by the battery charger protection instrumentstion. If a battery should become discharged or partially discharged and not be detected by existing indicators and alarns, the discharged condition would ' t identified within 7 days by surveillance testing. It is highly unlikely that the batteries would discharge in that period.
Question 6:
(1) llave you conducted a review of naintenance and testing activities to minimize the potential for human error causing more than one DC division to be unavailable? and (2) Do plant procedures prohibit maintenance or testing on redundant DC divisions at the same time?
Response
(1) Yes. A review has been performed at plant Vogtle to assess how best to minimize the possibility of taking two divisions of any safety-
, related system out of service at the same time due to human error.
The DC povier supply systems were considered as a part of that overall evaluatlon.
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ENCLOSURE 1 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT - UNil 1 INFORMATION,_ M ESTED IN GENER1(_1[TTER 91-06 (2) Yes, Plant procedures require maintenance work orders (MWO) to be generated for maintenance activities. Maintenance personnel must locate the equipment by identification tag number. Before taking the equipment out of service, a Shift Supervisor must review and approve the MWO. As part of the review, the Shift Supervisor must evaluate the MWO to determine: (1) if any operational deficiencies are associated with the maintenance that might require a report to the NRC, (2) if the maintenance work could have an adverse affect on plant operations and initiate any compensatory action determined to be appropriate, (3) if a limited condition for operation is necessary. (4) the appropriate operational mode for performance of the maintenance, and (5) If any special conditions are required.
Following the review, t'w Shift Supervisor signs and dates the MWO.
In order to further minimize the possibility of removing two divisions of safety-related equipment at the same time, planned maintenance and te ting activities are scheduled by train. During a specified week (s), these planned activities are performed only on Train A equipment. Work on Train B is scheduled for a different week (s).
Maintenance and testing activities are discussed during the " plan-of-tne-day" prior to the scheduled activity to assure that all affected organizational units are aware of the upcoming activities. To minimize the potential for removing a division of safety-related equipment from the wrong nuclear unit, work orders and surveillance task sheets are color coded, the floors in various areas of the plant are color coded, and the unit equipment identification tags are designed with different shapes.
Question 7:
Are ma;ntenance, surveillance and test procedures regarding station batteries con.lucted routinely at this plant? Specifically:
A. At lea:.t once per 7 days, are the following verified to be within acceptible limits:
- 1. Pilot cell electrolyte level?
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4 ENCLOSURE I (CONTINVED)
V0 GILE ELECTRIC CENERATING PLANT - UNil 1 JFFORMA1104 R(DEJi1LD ULSIRLB1C_ LETTER 91-06
- 2. Specific gravity or charging current?
- 3. float voltage?
- 4. Total bus voltage on float charge?
- 5. Physical condition of all cells?
B. At least once per 92 days, or within 7 days after a battery discharge, overcharge, or if the pilot cell readings are outside the 7-day surveillance requirements, are the following verified to be within acceptable limits:
- 1. Electrolyte level of each cell?
- 2. The average specific gravity of all cells?
- 3. The specific gravity of each cell?
- 4. The average electrolyte temperature of a representative number of cells?
- 5. The float voltage of each cell?
- 6. Visually inspect or measure resistance of terminals and connectors (including the connectors at the DC bus)?
C. At least every 18 months are the following verified:
- 1. Low resistance of each connection (by test)?
- 2. Physical condition of _ the battery?
~3. Battery charger capability to deliver rated ampere output to the DC bus?
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?
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ENCLOSURE 1 (CONTINUED)
V0 GILE ELEC1RIC GEN [RAllNG PLANT - UNIT 1 .
.lNf0RMA110N RLWISTED 11LG[NERIC LEITER 11-01 )
D. At least every 60 months, is capacity of each battery verified by performance of a discharge test?
E. At least annually, is the battery capacity verified by performance discharge test, if the battery shows signs of degradation or has reached 85% of the expected service life? ,
NRC statement regarding Question 7:
If the facility Technical Specifications have provisions equivalent to those-found in the Westinghouse and Combustion Engineering Standard Technical Specifications for maintenance and surveillance, then question 7 may be skipped and a statement to that effect may be inserted here.
Response
The facility Technical Specifications for Pl. t Vogtle Unit I have provisions for maintenance and surveillance of the DC power supplies that are equivalent to the Westinghouse Standard Technical Specifications (HUREG-OiS2).
Note: Revision 4 of NUREG-0452 specifies that an annual discharge test of battery capacity be performed on any battery that shows signs of degradation or has reached 80 percent of the service life expected for the application. The Technical Specifications for Plant Vogtle Unit I require this test to be performed at'least once each 18 months. The discharge test is normally performed during plant shutdown. Plant Vogtle utilizes an 18 month refueling cycle. Therefore, the 18-month battery discharge test is appr;opriate. Performance of the test once each 18 months is also in agreement with draft Revision 5 of NUREG-0452.
Question 8:
Does this plant 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 1
. El-S
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ENCLOSURE 1 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT - UNIT 1 INFORMA1JOH REqufSTED IN GQ1ERIC LETTER 91-06 B. Reactor coolant system intear'ty and isolation capability are maintained?
C. Operating procedures, instrumentation (including indicators and annunciators), and control functions are adequate to initiate systems as required to maintain adequate core cooling?
Response
A. Yes. The DC power supply system has two divisions, each of which is capable _ of supplying the DC power requirements for operating plant equipment necessary for reactor cooling.
B. Yes. Either of.the DC power supply systems is capable of providing DC power for the necessary isolation functions.
C. Yes.-The annunciator response procedures have been developed to respond to off-nor.aal conditions that deselop relative to the DC
_powei supply system. Operating procedures have been established to trcubleshoot and maintain stable conditions within the DC system.
Those procedures are referenced as appropriate in the annunciator response procedures. Emergency operating procedures are available for copir:g with conditions that progress or threaten to progress beyond a stable plant condition. Adequate instruinentation and controls are available to pravide the operators with the necessary.
-informatior, relative i the ststus of the DC systems, including the loss of one of the a divisions. With one division of DC power inoperable, surff .ie instrumentation and controls are available to operate the ner _3,n , J-dependent equipment to maintain core cooling.
Question.9:
41 the answer 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 the bases for not including the operational features cited.
-Response:
? No response nece'sary.
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ENCLOSURE 2 V0GTLE ELECTRIC GENERATING PLA T - UNIT-2 lll@RMATION RL0 VESTED IN GENERIC LETTER 91-06 Question 1:
Unit?
- Respense:
Unit 2.
Question 2:
A. The number of independent redundant divisions of Class lE or sue!y-related DC power for this plant is (include any separate C1 ss lE or safety-related DC, such as any DC dedicated to the
[
diesel generators.)
B. The number of 1ctional safety-related divisions of DC power-necessary to attain safe shutdown for this unit is.
Response
A. Two B. One Question 3'
- Does the control room at this unit have the following separate,
' independently annunciated alarms and indications for each division of DC power?
A.-Alarms
- 1. Battery disconnect or circuit breaker open?
- 3. DC system ground?
- 4. DC bus undervoltage?
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l
- 5. DC bus overvoltage?
- 6. Battery charger failure?
- 7. Battery discharge?
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l ENCLOSURE 2 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT - UNIT 2 .
INFORMA110N RE0 VESTED IN GENERIC LEFTER 91-06 B. Indications
- 1. Battery float charge current?
- 2. Battery circuit output current?
- 3. Battery discharge?
- 4. Bus voltage?
C. Does the unit have written procedures for response to the above alarms and indications?
Response: (See explanation regarding sharing of annunciator windows and
! justification for negative answers to questions 3.A.5, 3.A.7, 3.B.1, and 3.B.3 under the response to question 5.)
A. Alarms
- 1. Yes
- 2. Yes
- 3. Yes
- 4. Yes.
- 5. No 6; Yes
- 7. .No B. Indications i 'l. No
- 2. Yes
- 3. No
- 4. Yes.
C. Yes I.
E2-2
ENCLOSURE 2 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT - UNIT 2 INFORMATION req m lLQ_lN GENERIC LETTER 91-0_6 Question 4:
Does this unit have indication of bypassed and inoperable status of circuit breakers or other devices that can be used to disconnect the battery and battery charger from its DC bus and the battery charger from its AC power source during maintenance or testing?
Response
Yes. A loss of either the charger DC output or the AC input to the charger will be alarmed in the control room. if the MCC feeder breaker to the charger, the charger AC input breaker, the charger Dt. output breaker, or the DC switchgear breaker are opened, a battery charger trouble alarm will occur due to a loss of charger input, a charger AC input breaker open, and/or a loss of charger output (no-charge alarm). There is an alarm that will sound in the control room when the circuit breaker that connects the battery to the DC switchgear is opened, this alarm clears when the breaker is racked out. If the breaker is racked out for maintenance or testing the control room shift supervisor must sign off on the clearance and tagging procedure before work commences. Therefore, the control room operators will be aware of any battery or battery charger that is made inoperable. In addition, there are local indicators that display the DC current and voltage, which would be identified by operators making routine equipment surveillances.
Question 5:
If the answer to any part of (uestion 3 or 4 is no, then provide information justifying the existing design features of the facility's
-safety-related DC systems.
Response
falanation and Justification Relativ(Lip _ Question 3 A "yes" response to an alarm (3.A) indicates that there is a separate, independently annunciated alarm for the specific function in question. it does not mean that the specific function has a dedicated annunciator window. Several alarm signals may be transmitted and paralleled to a single annunciator window. As an example, Annunciator Window B04 for annunciator light board-34 on the electrical auxiliary board panel " Bat Chargers 2BDICA 2BDICB Trouble" would illuminate and an alarm would sound for the following conditions:
- 1. DC output overvoltage.
- 2. AC input voltage low.
- 3. Loss of DC output.
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l ENCLOSURE 2 (CONTINUED)
V0GTLE ELEC1RIC GENERATING PLANT - UNIT 2 INFORMATION REQUESTED IN GENERIC LETTER 91-00 This annunciator would alert the operator to a problem associated with one of the battery chargers that feed battery 2BDlB and switchgear 2BDl. The
, specific problem would then be ascertained and corrected in accordance with the appropriate annunciator response procedure. Since the functions are alarmed in the control room :nd any of the conditions that cause the annunciator to activate would be investigated and corrected, it is believed that the functions are adequately monitored, and a dedicated annunciator window for each alarm function is not necessary.
Question 3. A.5 - There is no overvoltage alarm in the control room that specifically monitors the DC bus, liowever, high DC output voltage from the battery charger would cause the circuit breaker in the charger input AC line to trip, which would in turn cause a control room battery charger trouble alarm. There is also an alarm on high voltage to the inverters, in addition, there is a system voltage indicator in the control room that would indicate an overvoltage condition. If the' bus voltage was high, the inverter high DC voltage would alarm, and the control room indicator would provide the operators the necessary information to determine the problem.
The annunciator response procedures would also require that an operator be dispatched to the affected area for further evaluation. Local instrumentation at the switchgear, battery chargers, inverters, or DC panels would confirm the specific problem.
Question 3.A.7 --There is no control room alarm that specifically indicates that a battery is being discharged. Control room indication is provided for battery current and bus voltage. A discharging battery carrying a significant load would be detected by the control room indicators. A bus undervoltage alarm would be received in the control room long before the batteries are discharged. Battery discharge can only occur when the outp'it of the battery charger cannot maintain the DC system voltage and current. There are two redundant battery chargers for each-bus and each is sized to maintain the bus at full load steady state plus maintain the battery at float voltage. It would take the failure of both chargers or a fault on the bus to cause the battery to discharge. Charger failure would be annunciated in the cor, trol room. Surveillance testing which would detect'a discharged condition is performed on a 7-day interval.
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,. 4 ENCLOSURE 2 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT - UNIT 2 IFFORMATION RE0V Gl[Q_IN GENERIC LETTER 91-06 Question 3.B.1 - There is no indicator in the control room that is capable of indicating the battery float current. The battery output current and the system voltage are indicated in the control room. The battery output current would normally indicate zero on the indicator.. If the battery charger should malfunction requiring the battery to feed the DC bus, the indicator in the control room would indicate the current flow. If for some reason the battery became discharged requiring a significant current flow from the charger to the battery, the ammeter would indicate the magnitude of ne current. If the proper float current is not maintained and the condition is not detected by the available monitoring instrumentation, it will be identified during the scheduled surveillance testing.
Question 3.B.3 - There is no control room indicator that specifically displays a battery discharge condition, but the battery outp.c current indicator would alert the coerators if a battery was carrying a significant load or if a large current was required to maintain a battery in the charged condition, it is very unlikely that a battery could-discharge without-being detected by existing instrumentation. A battery could not discharge to the D; bus unless there was a problem with a battery charger. Any battery charger trouble that would cause a battery to discharge to the bus would be detected and alarmed by the battery charger protection _ instrumentation. If a battery should become discharged or partially discharged and not be detected by exi; ting indicators and alarms, the discharged condition would be identified within 7 days by surveillance testing. It is highly unlikely that the batteries would discharge in:that period.
Question 6_:
(1) Have you conducted a review of maintenance and testing activities to minimize the potential for human error causing more than one DC division to be unavailable? and (2) Do plant procedures prohibit maintenance or testing on redundant DC divisions at the same time?
Response
t (1)-Yes. A review has been performed at Plant Vogtle to assess how best ,
to minimize the possibility of taking two divisions of any safety-related system out of service at the same time due to human error.
l The DC power supply systems were considered as a part of that overall evaluation.
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ENCLOSURE 2 (CONTINUED)
V0G1LE ELECTRIC GENERAllNG PLANT - UNIT 1 MORMAllMXQEllfD _lN GENERIC LETTER 91-06 (2) Yes. Plant procedures require maintenance work orders (MWO) to be generated for maintenance activities. Maintenance personnel must locate the equipment by identification tag number. Before taking the equipment out cf service, a Shift Supervisor must review and approve the MWO. As part of the review the Shift Supervisor must evaluate the MWO to determine: (1) if any operational deficiencies are associated with the maintenar.ce that might require a report to the NRC, (2) if the maintenance work could have an adverse affect on plant operations and initiate any compensatory action determined to be appropriate, (3) if a limited condition for operation is necessary, (4) the appropriate operational mode for performance of the maintenance, and (5) if any special conditions are required, following the review, the Shift Supervisor signs and dates the MWO.
In order to further minimize the possibility of removing two divisions of safety-related equipment at the same time, planned maintenance and testing activities are scheduled by train. During a specified week (s) these planned activities are performed only on Train A equipment.
Work on Train B is scheduled for a dif ferent week (s). Maintenance and testing activities are discussed during the " plan-of-the-day" prior to the scheduled activity to assure that all affected organizational units are aware of the upcoming activities. To minimize the potential for removing a division of safety-related equipment from the wrong nuclear unit, work orders and surveillance task sheets are color coded, the floors in various areas of the plant are color coded, and the unit equipment identification tags are designed with different shapes.
Question 7:
Are maintenance, surveillance and test procedures regarding station batteries conducted routinely at this plant? Specifically:
A. At least once per 7 days are the following verified to be within acceptable limits:
- 1. Pilot cell electrolyte level?
- 2. Specific gravity or charging current?
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.. s ENCLOSURE 2 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT - UNIT 2 JFEORMATION REQQfSTfD 11 LEG [EIC LElTER 91-06
- 3. Float voltage?
- 4. Total bus voltage on float charge?
- 5. Physical condition of all cells?
B. At least once per 92 days, or within 7 days after a battery discharge, overcharge, or if the pilot cell readings are outside the 7-day surveillance requirements, are the following verified to be within acceptable limits.
- 1. Electrolyte level of each cell?
- 2. The average specific gravity of all cells?
- 3. The specific gravity of each cell?
- 4. The average electrolyte temperature of a representative number of cells?
- 5. The float voltage of each cell?
- 6. Visually inspect or measure resistance of terminals and connectors (including the connectors at the DC bus)?
C. At least every 18 months are the following verified:
- 1. Low resistance of each connection (by test)?
- 2. Physical condition of the battery?
- 3. Battery charger capability to deliver rated ampere output to the DC bus?
- 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?
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ENCLOSURE 2 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT - UNIT 2 INFORMATIGN REQVLSlfLULG[NERIC LE11ER 91-01
- 0. At least every 60 months, is capacity of each battery verified by performance of a discharge test?
E. At least annually, is battery capacity verified by performance discharge test, if the battery shows signs of degradation or has reached 853, of the expected service life?
NRC statement regarding Question 7:
If the facility Technical Specifications have provisions equivalent to those found in the Westingheuse and Combustion Engineering Standard Technical Specifications- for maintenance and surveillance, then question 7 may be skipped and a statement to that effect may be inserted here.
Response
The facility Technical Specifications for Plant Vogtle Unit 2 have provisions for maintenance and surveillance of the DC power supplies that are equivalent to the Westinghouse Standard Technical Specifications (NUREG-0452).
Note: Revision 4 of NUREG-0452 specifies that an annual discharge test of battery capacity be performed on any battery that shows signs of degradation or has reached 80 percent of the service life expected for the application. The Technical Specifications for plant Vogtle Unit 2 require this test to be performed at least once each 18 months. The distharge test is normally performed during plant shutdown. Plant Vogtle utilizes an 18-month refueling cycle.
Therefore, the 18 month battery discharge test is appropriate.
Performance of the test once each 18 months is also in agreement with draft Revision 5 of NUREG-0452.
Question 8:
Does this plant 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?
B. Reactor coolant system integrity and isolation capability are maintained?
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. g ENCt.0SURE 2 (CONTINUED)
V0GTLE ELECTRIC GENERATING PLANT - UNIT 2 lt1 FORMATION RL0 VESTED IN E NERIC TETTER 91-_03 C. Operating procedures, instrumentation (including indicators and annunciators), and cor.tcol functions are adequate to initiate systems as required to maintain adequate core cooling?
Response
A. Yes. The DC power supply system has two divisions, each of whic'n a capable of supplying the DC power requirements for operating plant equipment necessery for reactor cooling.
B. Yes. Either of the DC power supply systems is capaMe of providing the necessary DC power for containment isolation.
C. Yes. The annunciator response procedures have been developed to respond to off-normal conditions that develop relative to the DC power supply system. Operating procedures have been established to troubleshoot and maintain stable conditions within the DC system.
Those procedures are referenced as appropriate in the annunciator response procedures. Emergency operating procedures are available for coping with conditions that progress or threaten to progress beyond a stable plant condition. Adequate instrumentation and controls arc available to provide the operators with the necessary inforenation relative to the status of the DC systems including the loss of one of the DC divisions. With one division of DC power inoperable, sufficient instrumentation and controls are -
available to operate the necessary DC-dependent equipment to maintain core cooling.
Question 9:
If the answer to any part of question 6, 7, or 8 is no then provide your
-basis for not perfcrming the maintenance, surveillance and test procedures described and/or the bases for not including the operational features cited.
Response
No response necessary.
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