ML20237H361

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Rev 7 to Abnormal Operating Instruction AOI-21.4, Loss of 125-Volt DC Vital Battery Board IV
ML20237H361
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-21.4, NUDOCS 8708170163
Download: ML20237H361 (6)
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Text

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l TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT l-l ABNORMAL OPERATING INSTRUCTION l

AOI-21.4

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LOSS OF 125V DC VITAL BATTERY BOARD IV

) Unit 1 -

Revision 7 I-PREPARED BY: R. Walker

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RESPONSIBLE SECTION: Operations .

REVISED BY: Jeff Epperson ,

SUBMITTED BY: , ,[ d u 6t-Supervisor PORC Review: PR 2 31987 l ate l' s <

APPROVED BY: /[7

~' Plant Manager

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DATE APPROVED: PR 231987 L

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

L Revised to correct annunciations and to move immediate actions to subsequent actions section. l t.

The last page of this instruction is number: 4 8700170163 870811 DR ADOCK 05000gg7 mm__ _ . _ . _ . - . _ . _

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SEQUOYAH NUCLEAR PLANT PLANT INSTRUCTION REVISION LOG ^

ABNORMAL OPERATING INSTRUCTION kOI-21.4 REVISION

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Date Pages REASON-FOR REVISION (INCLUDE COMMIT-LEVEL Approved Affected MENTS AND ALL ICF FORM NUMBERS) 1 '

, 06/21/77All 2 b9/25/78 4 3 09/18/79 All -

4

, 12/17/80 1

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'5' 07/20/83 All 6 08/13/84' 2 -

Revised to. correct annunciations and to 7 APRE' 3 IW All

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actions section.

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, A01-21.4 Page 1 of 4 Revision 7 .

I. SYMPTC!iS A. Possible alarms 1.

125V DC VITAL CHARGER IV FAILURE OF VITAL BATTERY IV DISCH 2.

I 3.

125V DC VITAL BATTERY BOARD IV ABNORMAL.

6900V SHUTDOWN BOARD 1B-B FAILURE OR BUS / NORMAL FE OR OVERVOLTAGE (1-M-1).

L 4. ~

6900V SHUTDOWN BOARD 1B-B FAILURE OR BUS / NORMAL FEE

-(0-M-26).

5.

480V SHUTDOWN BOARD IB1-B FAILURE OR UNDERVOLTAGE 6.

. 480V SHUTDOWN BOARD IB2-B FAILURE OR UNDERVOLTAGE 7.

6900V SHUTDOWN BOARD 2B-B FAILURE OR UNDERVOLTA I 8.

- I, 6900V (0-M-26).SHUTDOWN BOARD 2B-B FAILURE OR BUS / NORMAL FEEDE ~

9.

I. 480V SHUTDOWN BOARD 2B1-B FAILURE OR UNDERVOLTAGE (

10.

480V SHUTDOWN BOARD 2B2-B FAILURE OR UNDERVOLTAGE (2 11.

SERVICE AIR COMPRESSOR SEQUENCER UNDERVOLTAGE OR CO ALA -

B. Indications i -

1.

Voltmeter on 1-M-1 and 2-M-1 indicate failure of 125V de vital bus IV.

2.

Ammeter on 1-M-1 and 2-M-1 for bus IV vital battery shows zero. ' j R II. AUTOMATIC ACTIONS . ~

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A.

{ B.

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

4 Cask loading area ventilation supply and exhaust valves fail closed (FCV-30-130 and 30-123).

i C. 1 Auxiliary resulting building in loss ofHH2supply is lation valve FCV-77-241 failed closed 2

f VCT.

_ D.

All control and service air compressors will unload, resulting in decreasing control air pressure if sequencer power is from vital

. battery board IV (normally powered by vital battery board II). .

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,e SQN A0I-21.4 Page 7 of 4 Revision 7 ~

1- III. IMMEDIATE OPERATOR ACTION -

.. None IV. SUBSEQUENT OPERATOR ACTION

.A. Notify Assistant Shift Engineer (ASE) and Shift Engineer (SE).

B. Initiate REP per IP-1 (Engineered Safety Features) as required.

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

.. D. Transfer the following 125V de vital battery buses to alternate. feed.

( CAUTION: When transferring the 125V de bus to alternate or back to l normal, have someone hold the B.O. reset button pushed in, ,

located in panel 4 of.6.9kV logic panel IB-B. This wi.11 prevent the B.O. relays from going to a B.O. condition, which would sequence the CCP, AFWP, ERCW, PZR heaters, and fire pmaps if auto signal is present.

Xfer to Alt Return to Normal

1. 6.9kV shutdown board IB-B backup bus.
2. 480V shutdown board IB1-B backup bus.

3.

.480V shutdown board 1B2-B backup bus.

E. Depending upon the amount of time required for restoring 125V de bus 6

voltage, the diesel generators can be left running until restored or diesel generators IA-A, IB-B, and 2A-A 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 2B-B) in TEST position and leave it in TEST.
2. Place all 43T(L) switches (located on diesel generator logic panels IA-A, IB-B, and 2A-A) in the TEST position and then return them to NORMAL.
3. Reset the emergency start lockout relays for diesel generators IA-A, IB-B, 2A-A (located on each respective diesel generators relay panel in diesel generator building). -

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., - SQN A0I-21.4 Page 3 of 4 Revis' ion 7 '

IV. SUBSEQUENT OPERATOR ACTION (continued)

E. 4. Stop diesel generators IA-A, IB-B, and 2A-A by placing HS-82-14, HS-82-44, and HS-82-74 in STOP position.

5. Diesel generator 2B-B should be left running.

F. . Depending upon the cause of the failure or after repai rs, voltage can be I restored to the bus by placing the normal charger or -S spare charger in cervice or by connecting the battery to the bus by closing breaker 107.

CAUTION: If restoring voltage after a fault on the bus, use a-battery L

1' charger for energizing the bus if possible.

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

. Technical Specification 3.8.2.3.

I- G. After voltage is restored to the bus: ~

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

f 2. Open cask loading area ventilation supply and exhaust valves (FCV-30-130 and 30-123).

3. Open auxiliary building H2_ supply isolation valve FCV-77-241.
4. Return the diesel generators to their normal lineup by S01-82.1, 2, 3, and 4.

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V. REFERENCES A. Technical Specification 3.8.2.3.

B. FSAR 8.3.2

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. .C. Electrical Prints: 45N703-4 45N703-8 45N724-2 45N749-3 45N749-3 45N765-3 45N765-4 45N767-5 45N630-2 ,

45N630-3

_ 45N677-4 4

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.1 AOI-21.4

. Page 4 of 4 -

Revision 7 VI. DISCUSSION '

This instruction covers the loss of 125V de vital battery board IV voltage. .

This instruction assumes that Unit No. I is at power operation at the time of the event. The other three vital battery boards remain in normal operation throughout the duration of the event. The unit can remain at power operation with no cJegradation of the unit safety related systems.

Each 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 of, or a whole 125V de bus, actions should be t,aken to determine normal the cause as soon and extent of the loss and restore as much of the bus to as possible.

In general, 125V de vital battery board IV supplies control power for Unit

' 2 Train B equipment and solenoid valves; however, it does supply some equip-ment and contbol buses for Unit 1. The 125V de vital battery board bus IV

- can be energized by 125V de vital battery IV, from 125V de vital battery '

charger battery.

IV, from 125V de vital battery ' charger 2-S, or from the fifth vital G

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