ML20237H508

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Rev 4 to Abnormal Operating Instruction AOI-25.8, Loss of 120-Volt AC Vital Instrument Power Board 2-IV
ML20237H508
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 06/09/1987
From: Eaves H, Epperson J
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20237H133 List: ... further results
References
AOI-25.8, NUDOCS 8708170244
Download: ML20237H508 (6)
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TENNESSEE VALLEY AUTHORITY SEQUOYAH NUCLEAR PLANT t

ABNORMAL OPERATING INSTRUCTION, ,

AOI-25.8 LOSS OF 120V AC VITAL INSTRUMENT POWER BOARD 2-IV

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Unit 2 Revision 4 PREPARED BY: Herb Eaves _

RESPONSIBLE SECTION: Operations i e

Jeff Epperson REVISED BY: l SUBMITTED BY:. ,k,/ o sponsible Section Supervisor PORC REVIEW DAT : JUN 09 1987 APPROVED BY:

Plant Manager DATE APPROVED:

JUN 0 9 1987 Reason for revision (include all Instruction Change Form Nos.): l Revised to streamline operator actions. delete erroneous appendices A and B.

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The last page of this instruction is number: 4 -

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l 8708170244 870811

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,; .. l SEQUOYAH NUCLEAR PLANT.

PLANT INSTRUCTION REVISION LOG-AOI-25.8 .

I ABNORMAL OPERATING INSTRUCTIONS. )

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

_-O 08/04/81 - All

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1 09/12/83 All

- 1, 9 2 07/31/84 10/04/84 2

. . _3 Revised to. streamline operator actions, '

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g{ g jQg All delete erroneous appendices A and B. .

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, A0I-25.8 Page 1 Revision 4 I. SYMPTOMS A. Alarms

1. 120V AC VITAL I'NVERTER 2-IV ABNORMAL .

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2. 120V AC VITAL PWR BD 2-IV UV OR BREAKER TRIP B. Indications
1. Power Range N-44 failure. .
2. Auto and manual rod block and rod stop due to high flux rod stop, and C-5 interlock.
3. Loss of feedflow portion of signal to feedwater control  !

system resulting in failure to control steam generator level if channel IV is selected.

4. Loss of steam generator level control due to loss of -

input signal to program on steam generator 1 and 4.

5. Possible reactor trip due to steam generator level changes.
6. Loss of auto-makeup to VCT.
7. Malfunction of trip status lights and safeguards systems annunciators.

C. System Partial Failures i

1. Reduction of feedwater flow due to demand signal from steam generator 4 failing low.
2. Loss of power to Solid State Protection System input relays (Train A and B) and output relays (Train B) for channel IV.
3. Loss of steam generator power operated relief valves PIC-1-6A and PIC-1-31A if in normal mode. ,i
4. Loss of automatic control in auxiliary feedwater system '

of LCV-3-148, 171 (level control for steam generators 3 and 4) for motor driven AFH pump 2B-B.

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.' A0I-25.8 Page 2 Revision 4 I. SYMPTOMS (cont.)

5. Loss of automatic control in auxiliary feedwater system of LCV-3-173, 174 (level-control for steam generators'1 and 2) for turbine driven AFW pump 2A-S.

.[ NOTE: The above failures are of greatest immediate il consequences, for complete loads list of, vital board 2-IV see Appendix A.

II. AUTOMATIC ACTIONS f

A. Possible reactor. trip due to low-low S/G 1evel.

III. IMMEDIATE OPERATOR ACTIONS A. None --

IV. SUBSEOUENT OPERATOR ACTIONS A. If reactor trip occurs then refer to emergency. instructions.

B. If reactor does not trip, then, at the NIS panel, defeat the PR rod stop.

C. Assume and maintain manual rod control.

NOTE: Do not'use bank select; use of bank select will'cause the' bank overlap program to be lost.

D. Dispatch operator to restore power to failed board (transfer to auxiliary power supply).

E. Assume manual steam generator level control on the affected steam generators.

1 F. Transfer power operated relief valve PIC-1-6A and PIC-1-31A to the auxiliary control room. .

G. If power is restored to the failed boards, return systems to normal operating mode. ,

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_ SQN A0I-25.8 Page 3 Revision 4

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IV. SUBSEQUENT OPERATOR ACTIONS (Cont.)

l H. Evaluate need to shutdown per TS 3.8.2.1 if power cannot'be restored to the affected board. If necessary, commence orderly l- shutdown to the hot standby condition per GOI-5 and G0I-3.

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

NOTE: Operation may continue at the discretion of the Manager, Operations Group, with respect to Tech Spec.section 3.

I. Dispatch operator to Cardox units to verify master valves are closed.

V. REFERENCES A. TS 3.8.2.1, 3.8.2.2 B. S01-55 series C. 45N706-4. ,

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~ AOI-25.8 i > Page 4 Revision 4 ,

i APPENDIX A 9 Page 1 of I I

Load List: 120V AC Vital Inst. Power Bd. 2-IV SSPS (A) CH IV input relays (2-R-46)

SSPS (B) CH IV input and train B output relays (2-R-51) ,

NIS-instr. power CH IV NIS control power CH IV

Process. protection set IV (2-R-12) i lUHI accumulator CH IV isol. valve FCV-87-24 ERCH and containment rad, monitor RE-90-112

~Cntmt. annulus DP 2 PdIC-65-82

-I Aux. relay rack, SSPS aux. relays (2-R-78) -

RB isol . valve FCV-32-103A,103B __

Rad. rate meters and 2-RI-90-ll2 RCP'4 UV and UF relays

.I 125V de vital' battery bd. IV instruments EGTS room cooler A-A Post accident sampling solenoid valves PC0-65-83 and 87 aux. relays (2-R-78) _

BOP process instr. control rack (2-R-131)

AB instr. bus B Cntmt. purge air exhaust rad, monitor 2-RE-90-131 .

NSSS aux'. relay rack, B bus (2-R-55)

Aux. relay rack sep. and aux. relays (2-R-78)

Aux. control panel', B relay bus Aux, control panel, B instr. bus Aux, relay rack sep. and aux. relays (2-R-77)

BAT B htr. B-B controller TIT-62-245 Process control group 4 (2-R-22)

PIC-1-13A, 24A instr. bus 4 Reactor. vessel level instrumentation system B train plugmold (2-H-9)

UHI instr. bus 4 s ._

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