ML20237H492

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Rev 4 to Abnormal Operating Instruction AOI-25.6, Loss of 120-Volt AC Vital Instrument Power Board 2-II
ML20237H492
Person / Time
Site: Sequoyah  Tennessee Valley Authority icon.png
Issue date: 05/14/1987
From: Eaves H, Epperson J
TENNESSEE VALLEY AUTHORITY
To:
Shared Package
ML20237H133 List: ... further results
References
AOI-25.6, NUDOCS 8708170238
Download: ML20237H492 (6)
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Text

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TENNESSEE VALLEY AUTHORITY -

SEQUOYAH NUCLEAR PLANT "

ABNORMAL OPERATING INSTRUCTION AOI-25.6 LOSS OF 120V AC VITAL INSTRUMENT POWER BOARD 2-II

' Unit 2 I

Revision 4 PREPARED BY: Herb Eav'es RESPONSIBLE SECTION: Operations REVISED BY: . Jeff Erperson SUBMITTED BY:

Responsible Section Supervisor  !

PORC REVIEW DATE: MAY 141987 APPROVED BY:

Plant Manager

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DATE APPROVED: MAY 141987 l

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

Streamline Operator actions, delete erroroneous Appendices "A" and "B". This revision constitutes with AI-4, Appendix H. biennial revision in accordance l

L The last page of this instruction is number: 4 L i

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PLANT INSTRUCTION REVISION LOG '

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1 +~ ABNORMAL OPERATING INSTRUCTION A01-25.6 REVISION Date Pages REASON FOR REVISION (INILUDE COMMIT-LEVEL Approved Affected MENTS AND ALL ICF FCTM NUMBERS) 3 f 0 08/04/81 All ..

1 09/12/83 All "

2 07/31/84 1 3 10/04/84 2 1 l- Streamline Operator actions, delete erroroneous Appendices "A"  !

and "B". This revision constitutes

.I- 4 MAY 1 4 1987 All a biennial revision in accordance with AI-4, Appendix H. .

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A0I-25.6 .

Page'1 ,,

Revision 4 ' '

I. SYMPTOMS

- A. Alarms

1. '120V AC VITAL INVERTER 2-II ABNORMAL 2.

120V AC VITAL PWR SD 2-II UV OR BREAKER TRIP B. Indications

1. Power Range N-42 failure. -

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2.

Auto and manual rod block and rod stop due to high I3- flux rod stop and C-5 interlock.

3. Loss of steam flow portion of signal to feedwater l

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

[ 4.

l Loss or decrease of feedwater flow to all steam generators.

a 5. Possible reactor trip due to steam generator

'[ lo~-low level.

6. Malfunction of trip status lights and safeguards

] systems annunciators.

C. System Partial Failures 1.

Reduction of feedwater flow due to demand signal from steam generator 2 failing low. ,

1 2.

If a centrifugal charging pump is in operation an increase in charging fiow may result due to failure of FT-62-93 opening FCV-62-93; occur.

a resultant increase in seal injection flow would l

3.

Loss of power to solid state protection system input relays i'

(Train A and B) for Channel II.

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Revision 4

j I. . SYMPTOMS (continued) . .

.i L~: / C. System Partial Failures (continued) i

4. If pressurizer level is selected to LT-68-335 for control, pressurizer low level auto actions will occur.
5. If pressurizer pressure is selected to channel PT-68-334, the sprays will be closed and backup heaters energized

>I. until locked out by low level signal if LT-68-335 selected for level control. -

NOTE: The above failures are of greatest immediate consequences. For complete loads list of Vital Board 2-II refer to Appendix A.

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

III. IMMEDIATE OPERATOR ACTIONS A. None IV. SUBSEQUENT-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 (TREF signal is lost).

~ 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 control of steam generator water level on the

_ affected steam generators.

F.

Verify positive displacement charging pump is not in service since

^ speed controller is failed. Shif t charging to centrifugal pump is necessary. Transfer control of FCV-62-93 to auxiliary control room. -

G. Verify pressurizer level and pressure are not selected to LT-68-335 and PT-68-334. ...

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Page 3 Revision 4 "

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SUBSEQUENT OPERATOR ACTIONS (continued)

.{ < H. If power is restored to the failed boards, return systems

'l' to normal operating mode.

NOTE:

Due to feedback signals and time delays in circuitry, controllers may not control immediately.

.I.

I. Evaluate need to shutdown per TS 3.8.2.1 if power I cannot be restored to the affected board. If necessary commence orderly shutdown to the hot standby condition -

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u per GOI-5 and GOI-3. Initiate REP per IP-1 (Engineered Safety Features) as required. Refer to TS 3.8.2.2.

NOTE: Operation may continue at the discretion of the

. ~ Manager, operations group, with respect to Tech Spec section 3.

1. If shutdown is to continue to mode 5, follow G0I-3 l'i with exception: FCV-74-2 will require placing transfer SW. to aux. to open valve when RCS pressure is below 380 psig.
2. Transfer FCV-74-28 to aux. mode if B Train RHR is required for cooldown.

V. REFERENCES A. TS 3.8.2.1, 3.8.2.2 B. 501-55 series C. 45N706-2

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SON ADI-25.6 Page 4 Revision 4

i APPENDIX A _ ,

Page 1 of 1 Coad List: 120V AC Inst. Power Bd 2-II SSPS (A) CH II. input relays (2-R-46)

SSPS (B) CH II input relays (2-R-43)

NIS instr. power CH II NIS control power CH II Process protection set II (2-R-5)

L VHI accumulator CH II isol. valve FCV-87-22 RCP 2 UV and UF relay -

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AfWP turbine flow controller FIC-46-57 (alternate)

T0AfWP S/Gs 1 and 2 LIC-3-173, 174 TDAfWP S/Gs 1 and 2 instr. loop Reactor vessel level instrumentation system (2-R-148)

Incore temp. monitoring system Process control group 2 (2-R-17)

Plugmold instr. bus 2 (2-M-3)

Aux.l control panel B instr. bus Plugmold instr. bus 2 (2-M-6)

BOP process instr. control rack (2-R-122)

BOP process instr. control rack (2-R-130)

AB instr. B bus 1 Aux. relay rack, B b'us (2-R-76)

NSSS aux. relay rack, C bus (2-R-58)

NSSS aux, relay rack, B bus (2-R-58)

Aux relay rack, B bus (2-R-75)

Aux. relay rack, C bus (2-R-75)

Aux. control panel, B relay bus.

Aux, control panel, C relay bus Aux. control panel, B instr. bus Emerg. VHF radio Aux. relay rack, B bus (2-R-72)

Aux. relay rack, C bus (2-R-72)

Post accident monitoring.2 LOCA Hp,entmt. flow monitor XI-43-210 Inplant VHF radio repeater fl t

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