ML20237H421

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Rev 7 to Abnormal Operating Instruction AOI-21.8, Loss of 125-Volt DC Vital Battery Board IV
ML20237H421
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 04/27/1987
From: Brewer C, Epperson J
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20237H133 List: ... further results
References
AOI-21.8, NUDOCS 8708170205
Download: ML20237H421 (10)
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  • LESSEE VALLEY AUTHORITY 1

SEQUOYAH NUCLEAR PLANT ABNORMAL OPERATING INSTRUCTION AOI-21.8 LOSS OF 125V DC VITAL BATTERY BOARD IV Unit'2 l

Revision 7 -

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PREPARED BY: C. O. Brewer RESPONSIBLE SECTION: Operations l

REVISED BY: Jeff Epperson SUBMITTED BY- .O , / 11 __

pponsfbfeSectionSupervisor l._ APR 2 71987

PORC REVIE DATE:

APPROVED BY: }

Plant Manager

- DATE' APPROVED:

APR 2 71987 Reason for revision (include all Instruction Change Form Nos.):

Correct annunciations' delete PD charging pump reference.

The last page of this instruction is number:

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, 'SEQUOYAH NUCLEAR PLANT -

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PLANT INSTRUCTI'ON REVISION LOG 1, .

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ABNORMAL OPERATING INSTRUCTION AOI-21.8 REVISION Date Pages REASON FOR REVISION (INCLUDE COMMIT-LEVEL Approved Affected MENTS AND ALL ICF FORM NUMBERS)

I 11/03/79 All 2 06/24/80 6 3' 12/19/80 2

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4- 07/21/83 All

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5 08/13/84 2,3,6 g

Revised to add Vital Battery V to plant

'l 6 09/04/86 vital power sources and make correction All to automatic action section.

Correct annunciators; delete PD charging 7 APR 2 7 1997 All pump reference.

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A01-21.8 Page 1 I. SYMPTOMS A. Possible Alarms

1. 125V DC VITAL CHARGER IV FAILURE OR VITAL BATTERY IV DISCHARGE. ,
2. 125V DC VITAL BATTERY BOARD IV ABNORMAL.

3.

' ' 6900V SHUTDOWN BOARD 1B-B FAILURE OR~ BUS / NORMAL FEEDER -

UNDERVOLTAGE OR OVERVOLTAGE (1-M-1). -

4. 6900V SHUTDOWri BOARD 18-B FAILURE OR BUS / NORMAL FEEDER

'UNDERVOLTAGE (0-M-26).

S. 480V SHUTDOWN BOARD 1B1-B FAILURE OR UNDERVOLTAGE (1-M-1 and I 0-M-26). ,

6. 480V SHUTDOWN BOARD 182-8 FAILURE OR UNDERVOLTAGE (1-M-1 and 0-M-26).
7. 6900V SHUTDOWN BOARD 28-B FAILURE OR BUS / NORMAL FEEDER UNDERV0LTAGE OR OVERVOLTAGE (2-M-1).
8. 6900V SHUTDOWN BOARD 28-8 FAILURE OR BUS / NORMAL FEEDER UNDERVOLTAGE (0-M-26).
9. 480V SHUTDOWN BOARD 2B1-B FAILURE OR UNDERVOLTAGE (2-M-1 and 0-M-26).
10. 480V SHUTDOWN BOARD 282-B FAILURE OR UNDERVOLTAGE (2-M-1 and 0-M-26).
11. SERVICE-AIR COMPRESSOR SEQUENCER UNDERVOLTAGE OR CO ALARM

. (1-M-15).

B. Indications

1. Voltmeter on 1-M-1 and 2-M-1 indicates failure on 125V dc board IV.

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2. Ammeter on 1-M-1 and 2-M-1 for board IV battery shows zero.
3. Breaker position indicating lights for equipment feeding from

.] 6.9kV shutdown board 2B-B and 480V shutdown boards 2B1-B and 2B2-B will all be out. -

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A0I-21.8 Page 2 Revision 7 -

II. AUTOMATIC ACTIONS l A. Reactor-trip - turbine trip due to all four main feedwater regulating valves, all four MSIV's,'and number 1 and 3 S/G main feedwater regulating bypass valves falling closed resulting in loss of feedwater and-low steam generator water level in L

coincidence with steam flow / feed flow (SF/FF) mismatch and/or low-low steam generator water level.

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B. Motor-driven' auxiliary feedwater pump 2A-A and turbine driven, auxiliary feedwater pump 2A-S start on low-low steam generator

. water level (MDAFWP_28-B will not start).

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C. Steam dump valves and steam generator blowdown valves fail closed.

O. Letdown line isolation valve FCV-62-77 fails closed resulting in l' loss of letdown from RCS to CVCS.

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

F. All control and service air compressors will unload, resulting in decreasing control air pressure if sequencer power is from vital battery board IV (normally comes from vital battery board II).

5 III. IMMEDIATE OPERATOR ACTION A. Refer to emergency instructions IV. SUBSEQUENT OPERATOR ACTION A. Dispatch personnel to diagnose problem and attempt to restore power to 125V de vital battery board from:

1. 125V dc Battery IV or.

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2. 125V de Battery Charger IV or
3. 125V dc Battery Charger 2-S or
4. Spare Vital Battery IV with Battery V per SOI-250.5 B. Initiate a REP per IP-1 (Engineered Safety Features) as required.

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Page 3 F

' Revision 7

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IV. SUBSEQUENT 0PERATOR ACTION (continued)  !

C. Check transfer switch on. air compressor control panel in NORMAL.

l D. Maintain the reactor in hot standby.

I 1. Motor-driven auxiliary feedwater pump 2A-A will supply feedwater to steam generators 1 & 2 and turbine driven pump 2A-S will supply all four steam generators. Steam generator

,  : level should control automatically at : 33 percent. _

NOTE: Motor-driven auxiliary feedwater pump

{ '28-8 will not start.

2. All four steam generator atmospheric relief l! valves may be used for RCS heat removal

{ (modulating control only on steam generators 2 and 4). Steam generator relief valves can be adjusted to control RCS temperature at a 547'F.

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NOTE: Steam dump valves, main steam isolation valves, and all main feedwater regulating

valves to all four steam generators failed closed.

c 3. Place steam dump mode selector switch in

,. pressure mode.

4. . Isolate charging flow by closing FCV-62-90 or FCV-62-91. Verify or adjust reactor coolant pump seal water flow. 2A-A centrifugal charging pump may be started to establish seal injection flow.

. 5. Reactor coolant pumps can be stopped to reduce the heat removal requirements; however, reactor

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coolant pump No. 2 should be left on to supply pressurizer spray.

E. Verify pressurizer pressure normal and level increasing slowly.

NOTE: Excess letdown is not available since FCVs

_ 62-54 and 55 fall closed.

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AOI-21.8

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Page 4.

Revision 7 -

IV. SUBSEQUENT OPERATOR ACTION (continued)

NOTE: HIGH PRESSURE CONTROL - both pressurizer spray valves are operable and pressure relief valve PCV-68-340A is operable; however, pressurizer relief tank spray and RCDT pump discharge is isojated. (PRT drains to RCDT).

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NOTE: LOW PRESSURE CONTROL - pressurizer heaters control group 2D and backup group 2A-A are operable.

F. Have local inspection performed on 125V de vital battery boar'd IV to determine.cause of the failure. Try to restore voltage.

Initiate maintenance if necessary',

f G. Transfer the following 125V de buses to alternate feed.

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

. pushed in located in panel 4, of 6.9kV logic panel ,

i 28-B. This will prevent the 8.0. relays from going to.a B.O. condition, which would sequence the CCP, AFWP, ERCW, PZR heaters, and fire pumps if auto signal is present.

NOTE: After dc is restored to this bus, auxiliary feedwater pump 2B-B can be used to supply water to 3 and 4 steam generators.

Xfer to Alt Return to Normal

1. _ 6.9kV shutdown board 2B-B normal bus.

h,- 2. 480V shutdown board 281-B normal bus.

3. 480V shutdown board 2B2-B s normal bus.

H. Trip auxiliary building general supply and exhaust (

fans 2A and 2B and fuel-handling area exhaust fans A and B. Place auxiliary building gas treatment system train A in service.

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A0I-21.8 Page 5 Revision 7 .

IV. SUBSEQUENT OPERATOR ACTION (continued) 4 I. Trip containment annulus vacuum fans and place EGTS train A in service for Unit 2.

1. Open EGTS train A suction valve FCV-65-10.
2. Open EGTS train A discharge valve FCV-65-26.

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3. Open EGTS train A PCO isolation valves FCV-65-81 and .

PCV-65-86 (HS-65-81 on M-278). '

4. Start EGTS fan A-A JHS-65-23A on M-278).

J. Stop containment instrument room cooler that is operating.

K. If containment purge was in progress, .stop containment purge air supply and exhaust fans. -

L. Depending upon the amount of time required for restoring 125V dc bus voltage, the diesel generators can be left running or diesel

, generators lA-A, 2A-A, and 18-B can be stopped by the following procedure:

CAUTION: Coordinate this work with Unit 1 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 1A-A, 2A-A, and IB-B) in the TEST position simultaneously and then return them to NORMAL.

.L 3. Reset the emergency start lockout relays for diesel '

generators 1A-A, 2A-A, and 18-B (located on each respective diesel generator relay panel in diesel generator building).

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4. Stop diesel generators 1A-A, 2A-A, and 18-B from 0-M-26 panel j by placing HS-82-14, HS-82-74, and HS-82-44 in STOP position. l l
5. Diesel generator 2B-B should be left running.

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-IV. . SUBSEQUENT OPERATOR ACTION (continued)

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Pressurizer. level will slowly increase due to reactor coolant pump; seal water supplied to the RCS; it may take as little as two hours b (assuming 40 gpm total seal water flow) to fill the pressurizer.

If pressurizer level regches 92'/. trip the reactor coolant pumps-and'stop the charging pump.

N. Verify boron injection temperature > 145'F by TI-63-37 on panel r[. M-6.

, NOTE: Boric acid recirculation valves through BIT have failed closed.  ?.

O. Depending-upon the cause 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 connect.ing the battery to the. bus by closing breaker 107. '

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

NOTE: If board cannot be restored within two hours or less, refer to Technical Specification 3.8.2.3.

/ P. After normal voltage is restored to the bus:

l. Transfer the de buses back to normal that were charged in step IV.G of this procedure. Observe the same precautions (check off when normal).
2. Place 43T(L) switch (located on D.G. logic panel 28-B) to f NORMAL position.

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. 3. Reset the emergency lockout relay for D.G. 2B-8, then stop

.D.G. 2B-B. { i

4. Return the following systems to normal lineup and operation by their respective 50I.
a. CVCS System - S01-62.1. i'

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b. Reactor Coolant System - S01-68.1, 68.2, 68.3.

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A01-21.8 Page 7 .

Revision 7 IV. SUBSEQUENT OPERATOR ACTION (continued)

L' P. 4.. '(continued)

,, c. Auxiliary Feedwater System - S0I-3.2.

f d. Main Steam System - S01-1.1.

j. e. Steam Dump System - 501-1.2.

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Diesel Generators - SOI-82.1, 2, 3, 4.

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Boron Concentration Control - SOI-62.2.

h. Emergency Core Cooling System - 50I-63.1.
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Containment Vent and Cooling Systems - S0I-30.2,.30.3, and 30.4.

f j.. Emergency Gas Treatment System - S0I-65.1.

k. Auxiliary Building Heating and Ventilating System and l l1 Auxiliary Building Gas Treatment System - 501-30.5 and

(. 30.6.

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Control Building and Control Room Heating, Ventilation, and Air Conditioning System - S01-30.1.

m. ERCW System - SOI-67.1.
n. Component Cooling Water System - 50I-70.1.

, o. Haste Disposal System - SOI-77.1, 77.2, and 77.4.

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p. Steam Generator Blowdown System - S0I-3.3.
q. Reactor Protection System - S0I-99.1.

L Q. In the event of a change in the rated thermal power level exceeding 15% in one hour, notify the Chem Lab to initiate the conditional portions of SI-407.2 and SI-415 due to the thermal power change.

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s A01-21.8 Page 8 Revision 7 V. REFERENCES A. Technical Specification 3.8.2.3 B. FSAR 0.3.2 C. Electrical Prints: 45N703-4 45N703-8

, ! 45N724-2 45N749-3 _

45N749-4

,, 45N765-3,4 45N767-5, .

45N779-5, 45N600 thru 45N699 D. Logic Diagrams E. Control Diagrams VI. DISCUSSION l- This instruction covers the loss of 125V dc vital battery board IV

[ voltage. This instruction is for Unit 2 operation only and assumes that Unit 2 is at power operation at the time of the event. The other e three vital battery boards remain in normal operation throughout the duration of this event. The unit can be placed in and maintained in a safe shutdown condition. Each 125V de circuit is protected by a fuse or breakers to clear a fault. The 125V dc board is also divided into branch bases which are supplied with fuses or breakers to provide L. 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 dc bus, actions should be taken to determine the j cause and extent of the loss and restore as much of the bus to normal  !

as soon as possible.

In general, 125V dc vital battery board IV supplies control power for i Unit 2 train B equipment and solenoid valves. 125-V bus IV can be energized by 125V de battery IV, from 125V de vital battery charger ,

IV, from 125V dc vital battery charger 2-S, or from 5th vital battery. l I

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