ML20237H281
| ML20237H281 | |
| Person / Time | |
|---|---|
| Site: | Sequoyah  |
| Issue date: | 05/14/1987 |
| From: | Epperson J, Jacqwan Walker TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML20237H133 | List:
|
| References | |
| AOI-21.1, NUDOCS 8708170131 | |
| Download: ML20237H281 (11) | |
Text
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TENNESSEE VALLEY AUTHORITY
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SEQUOYAH NUCLEAR PLANT ABNORMAL OPERATING INSTRUCTION AOI-21.1 LOSS OF 125V DC VITAL BATTERY BOARD I Unit 1 Revision 10 PREPARED BY:
J.
R.
Walker RESPONSIBLE SECTION:
Operations REVISED BY:
Jeff Epperson SUBMITTED BY:.
(An h
sp6n'sible Section Supervisor PORC REVIEW DATE:
MAY 141987 APPROVED BY:
Plant Manager DATE APPROVED:
MAY I 41987 Reason for revision (include all Instruction Change Form Nos.);
Revised to correct annunciations, delete PD charging pump reference and change immediate actions.
The last page of this instruction is number:
9 8
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SEQUOYAH NUCLEAR PLANT PLANT INSTRUCTION REVISION LOG 9'
ABNORMAL OPERATING INSTRUCTION AOI-21.1-
- REVISION Date Pages REASON-FOR REVISION.(INCLUDE COMMIT-LEVEL Approved Affected MENTS AND ALL ICF FORM NUMBERS) 5 09/17/80 All 6
03/10/81 2
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~7 07/20/83 All 8
08/13/84 2,4,7 Revised to add Vital Battery V to plant vital power sources and make correction-9 09/04/86 1,2,8 to automatic operation section.
I Revised to correct annunciations, delete
.ugy 4 A may 3 PD charging pump refmrence and change 1
10 mni A 7 10 0 /
All immediate actions.
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0514C/ldw A._
Page 1 of 8 Revision'10 I.
SYMPTOMS
' i A.
Possible Alarms i
1.
125V DC VITAL CHARGER I FAILURE OR VITAL BATTERY I DISCHARGE.
j 2.
125V DC VITAL BATTERY BOARD I ABNORMAL.
3.
6900V SHUTDOWN BOARD 1A-A FAILURE OR BUS / NORMAL FEEDER UNDER-VOLTAGE OR OVERVOLTAGE (1-M-1).
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4.
6900V SHUTDOWN BOARD 1A-A FAILURE OR BUS / NORMAL FEEDER UNDER-VOLTAGE (0-M-26).
5.
480V SHUTDOWN BOARD 1Al-A FAILURE OR UNDERVOLTAGE (1-M-1 and 0-M-26).
6.
480V SHUTDOWN BOARD 1A2-A FAILURE OR UNDERVOLTAGE (1-M-1 and 0-M-26).
t 7.
6900V SHUTDOWN BOARD 2A-A FAILURE OR BUS / NORMAL FEEDER UNDERVOLTAGE OR OVERVOLTAGE (2-M-1).
B.
6900V SHUTDOWN BOARD 2A-A FAILURE OR BUS / NORMAL FEEDER UNDERVOLTAGE (C-M-26).
9.
480V SHUTDOWN BOARD 2Al-A FAILURE OR UNDERVOLTAGE (2-M-1 and 0-M-26).
10.
480V SHUTDOWN BOARD 2A2-A FAILURE OR UNDERVOLTAGE (2-M-1 and 0-M-26).
11.
PANEL 1-L-39 GENERATOR AUXILIARY ANNUNCIATOR OPERATED OR BUS POWER FAILED (1-M-2).
r B.
Indications 1.
Voltmeter on 1-M-1 and 2-M-1 indicates failure on 125V de bus I.
2.
Ammeter on 1-M-1 and 2-M-1 for bus I battery shows zero.
3.
Breaker position indicating lights for equipment feeding from 6.9kV shutdown board 1A-A and 480V shutdown boards 1Al-A and 1A2-A will
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all be out.
II.
AUTOMATIC ACTIONS A.
Reactor trip - turbine trip due to all four main feedwater regulating valves, all four MSIVs, and Nos.2 and 4 SG main feedwater regulating bypass valves failing closed resulting in loss of feedwater, and low steam generator water level in c.oincidence with steam flow / feed flow (SF/FF) mismatch and/or low-low steam generator water level.
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r-SQN A0I-21.1
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P.sge 2 of 8 Revision 10 LII. AUTOMATIC ACTIONS (Continued)
B.
Motor driven auxiliary feedwater pump 1B-B and turbine driven auxiliary' feedwater pump start on low-low steam generator water level (MDAFWP
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1A-A will not start).
r C.
Steam dump valves and steam generator blowdown valves fail closed.
D.
Normal letdown isolation valves FCV-62-69 and 62-70 and orifice isola-tion valves'FCV-62-72, 62-73, and 62-74 fail closed.
E.
All four diesel generators start but do not tie onto the shutdown boards.
III. IMMEDIATE OPERATOR ACTION A.
Refer to emergency instructions.
i IV.
SUBSEQUENT OPERATOR ACTION A.
Dispatch personnel to diagnose problem and attempt to restore power to 125V de vital battery board from:
1.
125V de Battery.1 or 2.
125V Vital Battery Charger 1 or 3.
125V de Vital Battery Charger 1-S or
'4.
Spare Vital Battery I with Battery V per S0I-250.5 B.
Initiate REP per IP-1 (Engineered Safety Features) as required.
C.
Maintain the reactor in hot standby.
1.
Motor driven auxiliary feedwater pump 1B-B will supply feedwater to steam generators 3 and 4 and turbine driven pump 1A-S will supply all four steam generators.
Steam generator level should control automatically at equal to or approximately 33 percent.
NOTE:
Motor driven auxiliary feedwater pump 1A-A will not start.
)
2.
All four steam generator atmospheric relief valves may be used for RCS heat removal (modulating control only on steam generators 1 and 3).
Steam generator relief valves can be adjusted to control RCS temperature at equal to or approximately 547 F.
NOTE:
Steam dump valves, main steam isolation valves, and all main feedwater regulation valves to all' four steam generators failed closed.
NOTE:
See Appendix A for equipment not available.
m,
_ _ _ _ _ _ _ _ ~. _ _ _ _ _ _ _ _. _ _. _ _ _ _. _ _ _ _ _ _ _. _
d
> Revision 10 IV.
SUBSEQUENT OPERATOR ACTION (Continued) 3.
Place steam dump mode selector switch to pressure control mode.
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4.
Isolate charging flow by closing FCV-62-90 or 62-91 (FCV-62-86 has failed closed). Verify reactor coolant seal flow in operating band (FCV-62-90 or 62-91 may be used as needed to mrintain pressurizer level).
1B-B centrifugal charging pump may be started to establish seal injection.
NOTE:
The control of RCS boron concentration will be degraded due to the blender being isolated to the VCT via failed valve 62-144.
Also valve FCV-62-140 (BAT modulating valve) fails open.
5.
Reactor coolant pumps can be stopped to reduce the heat input; however, t
reactor coolant pump No. 2 should be lef t on to supply pressurizer spray if possible.
6.
Place excess letdown system in service per SOI-62.1.
Use charging pump suction valves from RWST as necessary to maintain VCT level between 7 and 80% (FCV-62-135 and 136).
NOTE:
The only fill to the VCT is from excess letdown and RCP seal return.
(blender and normal letdown L
failed).
D.
Verify pressurizer pressure normal and level being maintained.
NOTE:
Both PZR spray valves are operable and relief valve PCV-68-334 is operable; HOWEVER, the pressurizer relief tank cannot be drained, vented, supplied with N, samP ed, or cooled by primary l
2 water due to failure of valves necessary for these operations.
L Pressurizer auxiliary spray is unavailable due to FCV-62-84 failing closed. Pressurizer back-up heaters, groups IC and 1B-B are operable. Heater IA-A will fail in the "as is" condition and ID will be controlled by the SCR.
E.
Have a local inspection performed on 125V de vital battery board I to determine the cause of the failure.
Try to restore voltage.
Initiate maintenance if necessary.
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SQN A0I-21.1 Page 4 of 8 Revision 10 IV.
SUBSEQUENT OPERATOR ACTION (Continued)
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F.
Transfer the following 125V de buses to alternate feed.
r CAUTION: While transferring the de to the normal de bus from battery board Ioto battery board III, have someone hold the B.O. reset button pushed in, located in panel 4 of 6.9 kV logic panel IA-A; this will prevent the B.O. re-lays from going to B.O. condition, which would sequence the CCP, AFWP, ERCW, CCSP, PZR heaters, and fire pumps if they had an auto start signal present.
NOTE:
After de is restored to this bus, auxiliary feedwater pump 1A-A can be used to supply water to steam generators 1 and 2.
I Xfer To Alt Return to Normal 1.
6.9kV shutdown board 1A-A normal bus.
2.
480V shutdown board 1Al-A normal bus.
3.
480V shutdown board 1A2-A normal bus.
CAUTION:
Control and service air compressor A will trip when de is restored to this bus. Must be reset locally.
4.
480V auxiliary building common board normal bus.
CAUTION:
Control and service air compressors C & D will trip when de is restored to this bus. Must be reset locally.
G.
Stop auxiliary building general supply and exhaust fans IA and IB and fuel handling area exhaust fans A and B.
Place auxiliary building gas treatment system train B in service.
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~H.
Trip containment annulus vacuum fans and place EGTS train B in service for Unit 1.
1.
Open EGTS train B suction valve FCV-65-30.
2.
Open EGTS train B discharge valve FCV-65-45.
i 3.
Open EGTS train B PC0 isolation valve PCO-65-83 and PCV-65-87 i
(HS-65-83 on M-27B).
4.
Start EGTS fan B-B (HS-65-42A on M-278).
I.
Stop containment instrument room cooler that is operating.
J.
I:
containment purge was in progress, stop containment purge air supply and exhaust fans.
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SQN A01-21.1 Page 5 of 8 Revision 10 IV.
SUBSEQUENT OPERATOR ACTION (Continued)
K.
Depending upon the amount of time required for restoring 125V de bus
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voltage, the diesel generators can be left running or diesel generators IB-B, 2A-A, 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 panels 1A-A) in TEST position and leave it in TEST.
f 2.
Place all 43T(L) switches (located on diesel generator logic panels I
1B-B, 2A-A, and 2B-B) in the TEST position and then return them to NORMAL.
3.
Reset the emergency start lockout relays for diesel generators IB-B, 2A-A, and 2B-B (located on each respective diesel generator relay panel in diesel generator building).
4.
Stop diesel generators 1B-B, 2A-A, and 2B-B by placing HS-82-44, HS-82-74, and HS-82-104 in STOP position.
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5.
Diesel generator 1A-A should be left running.
1 L.
If power cannot be restored to the board, proceed from Hot Standby to Cold Shutdown per GOI-3B.
NOTE:
The following equipment called for in GOI-3B is not available due to the loss of the 125V battery board I.
1.
Auxiliary spray from the charging pumps due to the loss of FCV-62-84.
2.
Steam dump valves all fail closed.
3.
Main feedwater is isolated due to all four MFW reg. valves failing closed.
4.
Main steam lines isolate due to all four MSIVs failing closed.
5.
Sampling for hot legs 1 and 3 (pressurizer liquid and gas) due to failed closed position of FCV-43-23, 12, and 3, respectively.
6.
Reactor coolant pump seal bypass (FCV-62-53) fails closed and cannot be opened.
7.
Sampling steam generator water quality due to steam generator blowdown valves FCV-1-14, 32, 181, and 183 failing closed.
Therefore, the use of the auxiliary feedwater system, RCS' makeup from the refueling water storage tank, pressurizer spray from the RCS loop (s), steam release from steam generator relief valves as g
instructed in section IV. C. and D. should be maintained.
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Page 6 of 8' Revision 10 IV.
SUBSEQUENT OPERATOR ACTION (Continued)
=w M.
Verify. boron injection temperature equal to or greater than145 F by
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TI-63-27 on panel M-6.
\\7 N.
Depending upon the cause of the failure, or after repairs, voltage can be restored to the bus by placing the normal. charger or 1-S spare charger in
. service or by connecting the battery to the bus by closing breaker 107.
CAUTION:
If restoring voltage af ter a fault on the bus, use a battery l
charger ~ for energizing the bus, if possible.
J' NOTE:
If board cannot be restored within two hours of loss, refer to Technical Specification 3.8,2.3.
O.
After normal voltage is restored to the bus:
1.
Transfer the de buses back to normal that were changed in step IV.F. of this procedure.
Observe the same precautions (check off when returned to normal).
2.
Place 43T(L) switch (located on diesel generator logic panel 1A-A) to NORMAL position.
3.
Reset the emergency start lockout relay for diesel generator IA-A;.
then stop diesel generator 1A-A.
u 4.
~ Return the following systems to normal operation by their respective SOIs.
4 i
a.
CVCS System - SOI-62.1 b.
Reactor Coolant System - SOI-68.1, 68.2, 68.3 Auxiliary Feedwater System - SOI-3.2 c.
d.
Main Steam System - S0I-1.1.
e.
Steam Dump Control - SOI-1.2 f.
Diesel Generators - SOI-82.1, 82.2, 82.3, 82.4 8
Boron Concentration Control - S0I-62.2 h.
Emergency Core Cooling System - S01-63.1 i.
Containment Vent and Cooling System - SOI-30.2,
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30.3, 30.4
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e m.
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SQN A0I-21.1 Page 7 of 8 Revision 10 IV.
SUBSEQUENT OPERATOR ACTION (Continued) j.
Auxiliary Building Heating and Vent System and
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Auxiliary Building Gas Treatment System - S0I-30.5 l'
r and 30.6 k.
Emergency Gas Treatment System - SOI-65.1 1.
Control Building and Control Room Heating, Air Conditioning, and Ventilation System - SOI-30.1 m.
n.
Component Cooling Water System - SOI-70.1
,__ Waste Disposal System - S0I-77.1, 77.2, 77.4 o.
p.
Ice Condenser System - S0I-61.1 q.
Steam Generator Blowdown System - SOI-15 r.
Reactor Protection System - SOI-99.1 P.
In the event of a change in 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.
Q.
Return the following to normal line-up as necessary, Main Feedwater (Valves and Pumps) a.
b.
Extraction Steam Control Bldg. Pressurizing Fans c.
d.
Incore Instrument Room Cooling
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e.
Upper Head Injection f.
Radiation Monitoring V. REFERENCES A.
Technical Specification 3.8.2.3 B.
FSAR 8.3.2 m
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_SQN AOI-21.1 Page 8 of 8 Revision 10 V.
REFERENCES (Continued).
~c C.
Electrical Prints: 45N703-1
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45N703-5 I
45N724-1 45N749-1 45N749-2 45N765-3
-45N767-5 45N779-6 45N600 through 45N699 VI. DISCUSSION This instruction covers the-loss of 125V de. vital battery board I voltage.
This instruction assumes that Unit 1 is at power operation at the time of the event and the three other vital battery boards remain in normal operation. The unit can be placed in,'and maintained in, a safe. shutdown condition.
In General, 125V de battery board I supplies control power for Unit I train A equipment and motive power for many solenoid valves (mainly Unit I train A).
The loss of control power causes~the breakers on the affected boards (normally Unit.1, 6.9kV and 480V shutdown boards) to fail "as is."
As a result of the power loss to the solenoid valves, main feedwater and main steam flow will be terminated and the reactor will trip. Safe shutdown is maintained with the steam generator power-operated relief valves and Auxiliary Feedwater System.
Cooldown control to the cold shutdown condition is via the Residual Heat Removal System.
-125V Bus I can be energized by 125V de battery I, from 125V de vital battery charger 1, from 125V de vital battery charger 1-S, or from Sth vital battery.
Each 125V de circuit is protected by a fuse or breaker to clear a fault.
The 125V de board is also divided into " branch buses" which are supplied with fuses or breakers to provide redundant protection from a fault and prevent a loss of the board due to a single fault.
In any situation involving loss of.
a part of, 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 is possible.
The loss of control power causes the breakers on the affected boards to fail "as is."
As a result it wi'll be necessary to use auxiliary control power if
' breaker operation is needed.
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4 SQN AOI-21.1 Appendix A Page 1 of 1 Revision 10 EQUIPMENT MADE UNAVAILABLE 1
o 1.' Unit 2 Auxiliary Feedwater Pump Turbine Control 2.
Generator Auxiliary Panel (1-L-39) 3.
Boric Acid Evaporator (Package A) 4.
Gas Analyzer (Sample Valve Failed Closed) 5.
Emergency DC Lighting Cabinet LD-1 6.
Extraction Steam Dump Valves (FCV-5-94 to 98) 7.
Auxiliary Building General Ventilation (Dampers Failed Closed) 8.
Reactor Building Purge (Dampers Failed Closed) 9.
Fuel }Iandling Area Ventilation (Dampers Failed Closed) 10.
Annulus to Lower Compartment AP Indication
- 11. RCS and Pressurizer Sample (Root Valves Failed Closed) 12.
Refrigerant Flow to Ice Condenser Coolers and Incore Inst. Rocm Coolers 13.
Train A ERCW TCVs in Containment (Failed Open)
- 14. Reactor Coolant Drain Tank Isolated (Discharge, Vent N2 Supply, and Gas Sample)
- 15. RM-90-106 and 112 Sample Valves Failed Shut.
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