ML20237H348

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Rev 7 to Abnormal Operating Instruction AOI-21.3, Loss of 125-Volt DC Vital Battery Board III
ML20237H348
Person / Time
Site: Sequoyah Tennessee Valley Authority icon.png
Issue date: 04/23/1987
From: Epperson J, Jacqwan Walker
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20237H133 List: ... further results
References
AOI-21.3, NUDOCS 8708170157
Download: ML20237H348 (6)
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Text

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TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT -

ABNORMAL OPERATING INSTRUCTION AOI-21.3 s

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LOSS OF 125V DC VITAL BATTERY BOARD III

'1 Unit 1 Revision 7

.I PREPARED $Y: J. R. Walker I-RESPONSIBLE SECTION: Operation's .

REVISED BY: Jeff Epp.erson ,

SUBMITTED BY* .

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{j Sdpervisor PORC Review': APR 2 31987 Date APPROVED BY: "(

Plant Manager

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DATE APPROVED: 3 hl17 L

Reason for revision (include all Instruction Change Form Nos.):

Revised to correct annunciations and to move immediate actions to-subsequent actions section.

The,last page of this instruction is number: 4 s -

8708170157 870811

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1 I l SEQUOYAH NUCLEAR PLANT *

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PLANT INSTRUCTION REVISION LOG

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ABNORMAL OPERATING INSTRUCTION AOI-21.3 REVISION Date Pages REASON FOR REVISION (INCLUDE COMMIT-LEVEL Approved Affected MENTS AND ALL ICF FORM NUMBERS) 1 1 06/21/77 All 2 10/05/78 4 3 09/20/79 All 4 12/19/80 2 5 07/26/83 All I '

l 6 07/31/84 2 - -

Revised to correct annunciations and to move immediate actions to subsequent 7 APR 2 3 1987 All actions section.

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Page 1 of 4 Revision 7 q

LOSS OF 125V DC VITAL BATTERY BOARD III ~~ i

, ~I. SYMPTOMS i

A. Possible alarms 1.

125V DC VITAL CHARGER III FAILURE OR VITAL BATTERY III DISCHARGE.

2. '125VDC.VITALBATYERYBOARDIIIABNORMAL.

3 .'

6900V SHUTDOWN BOARD 1A-A FAILURE OR BUS /NGRMAL FEEDER UNDERV OR OVERVOLTAGE (1-M-1).

e 4.

, 6900V SHUTDOWN BOARD 1A-A FAILURE OR BUS / NORMAL FEEDER UNDE (0-M-26).

5.

~480V SHUTDOWN BOARD 1Al-A FAILURE OR UNDERVOLTAGE 6.

480V SHUTDOWN BOARD 1A2-A FAILURE OR UNDERVOLTAGE (1-M-1 an 7.

l. 8.

6900V SHUTDOWN BOARD 2A-A FAILURE OR BUS / NORMAL FEEDER UNDERV OR OVERVOLTAGE (2-M-1).

6900V SHUTDOWN BOARD 2A-A FAILURE OR BUS / NORMAL FEEDER UNDERV (0-M-26).

9.

480V SHUTDOWN BOARD 2Al-A FAILURE OR UNDERVOLTAGE (2-M-1 and 10.

480V SHUTDOWN BOARD 2A2-A FAILURE OR UNDERVOLTAGE (2-M-1 and B. Indications 1.

. Voltmeter III.

on 1-M-1 and 2-M-1 indicates failure of 125V de vital bus

2. Ammeter on 1-M-1 and 2-M-1 for bus III vital battery shows zero.
3. Position indicating lights for auxiliary feedwater pump 1A-S T&T valve will be out (located on panel 1-M-3).

II. AUTOMATIC ACTIONS A.

All four diesel generators start but do not tie onto the shutdown boards.

B.

Cask loading area ventilation supply and exhaust valves fail' closed (FCOs30-122 and 30-129).

C. Auxiliary building H2 SUPP l y isolation valve FCV-77-240 failed closed resulting in loss of H t VCT.

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'A0I-21.3 Page.2 of 4 Revision 7 "

III. I&fEDIATE OPERATOR ACTION

1 None IV. SUBSEQUENT OPERATOR ACTION A. Notify Assistant Shift Engineer (ASE) and Shift Engineer (SE).

B. Initiate REP per IPl (Engineered Safety Features) as required.

g C. Have an inspection performed on 125V de vital battery board III to l determine the cause of the failure. Try to restore voltage. - Initiate maintenance if necessary.

D. Transfer turbine driven auxiliary feedwater pump 1A-S control circuit to I alternate supply (located on local panel).

E.

Transfer the following 12SV de vital battery buses to alternate feed.

CAUTION: When transferring the 125V d'c bus to alternate or back to normal, have someone hold the B.O. reset button pushed in located in

-I panel 4 of 6.9kV logic panel 1A-A. This will prevent the B.O.

relays from going to B.O. condition, which would sequence the CCP, AFWP, ERCW, PZR heaters, and fire pumps if auto start signal is present.

Xfer to Alt Return to Normal

1. 6.9kV shutdown board 1A-A (backup) bus.
2. 480V shutdown board 1Al-A backup bus.
3. 480V shutdown board 1A2-A backup bus.

~ F. Depending upon the amount of time required for restoring 125V de bus voltage, the diesel generators can be left running until restored or diesel generators 1A-A, IB-B, and 2B-B can be stopped by the following procedure:

CAUTION: Coordinate this work with Unit 2 operator.

1. Place 43T(L) switch (located on diesel generator logic panel 2A-A) in TEST position and leave it in TEST.
2. Place all 43T(L) switches (located on diesel generator logic panels 1A-A, IB-B, and 2B-B) in the TEST position simultaneously and return thua to normal.
3. Reset the emergency start lockout relays for diesel generator's IA-A, IB-B, and 2B-B (located on each respective diesel generator relay panel).

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- 4 SQN A0I-21.3 Page'3 of 4 Revision 7 '

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IV. SUBSEQUENT OPERATOR ACTION (continued) -

G. 4. Stop diesel generators IA-A, IB-B, and 2B-B by placing HS-82-14, HS-82-44, and HS-82-104 in STOP position.

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5. Diesel generator 2A-A should be left running. i H. Depending upon the caust of the failure or after repairs, voltage can be restored to the bus by placing the normal charger or 2-S spare charger'in service or by connecting the battery to the bus by closing breaker 107.

CAUTION: If restoring voltage after a fault on the bus, nse a battery charger for energizing the bus if possible.

NOTE: If board cannot ic restored within two hours of loss, refer to

. Technical Specificati,on 3.8.2.3.

I I. After voltage is restoged to the bus: *

1. Transfer the de buses back to normal that were changed in step i IV.E of this procedure. Observe the same precautions (check off when norraal).

'l~ 2. Open cask loading area ventilation supply and ex'haust valves (FCV , 122 and 30-129).

3. Open auxiliary building H 2 SUPP l y isolation valve FCV-77-240.
4. Return the diesel generators to their normal lineup by S0I-82.1, 2, 3, 4.
5. Transfer turbine driven auxiliary feedwater pump 1-S control circuit back to normal.

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A0I-21.3 '

Page 4 of 4 .

Revision 7

' V. REFERENCES -

A. Technical Specification 3.8.2.3 _

B. FSAR 8.3.2

_ C. Electrical Prints - 45N703-3 45NJ03-7 45N724-1 45N749-1 45N749-2 I" 45N765-3

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45N765-4 45N767-5 1 45N630-2 45N630-3 s

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l VI. DISCUSSION ,

' ~ This instruction covers the loss of 125V de vital battery board III voltage. This instruction assumes that Unit No. 1 is at power operation at the time of the event. The other three vital battery boards remain in normal operation throughout the duration of this event. The unit can remain at power operation with no degration of the unit safety related systems.

Each 125V de circuit is protected by a fuse or breaker to clear a fault.

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' The 125V de board is also divided into branch buses which are supplied with fuses or breakers to provide redundant protection for a fault and prevent a loss of the board due to a fault in one circuit. In any situation involving loss of a part, or a whole 125V de bus, actions should be taken to determine the cause and extent of the loss and restore as much of the bus to normal as soon as possible, j

In general, 125V de battery board III supplies control power for Unit 2 )

Train A equipment and solenoid valves; however, it does supply control power (

to some equipment and control buses for Unit No. 1. 125V de bus III can j be energized by 125V de battery III, from 125V de vital battery charger _q III, from 125V de vital battery charger 2-S, or from the fifth vital battery.

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