ML19309D602

Forwards Response to IE Bulletin 79-27.Loss of Class IE Bus Would Not Significantly Affect Instrumentation Panels.Some Functions Not Related to Achieving Cold Shutdown Are Temporarily Lost

ML19309D602
Person / Time
Site:	Farley
Issue date:	03/13/1980
From:	Clayton F ALABAMA POWER CO.
To:	James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
References
IEB-79-27, NUDOCS 8004110003
Download: ML19309D602 (5)

Text

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.. Alab:ma Power Company .

f, 600 North 18th Street 9, g/(, '-

Post Offica Com 2641 Berrmnghcm Al:bims 35291 .",.

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Telephone 205 323-5341 , ,,

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3 ,a t F. L. CLAYTON, JR.

m Senior Vice President Alabama Power f' O

• bJ n sden Mwkm March 13, 1980

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Ibcket 50-348 NIC Region II

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Mr. Janes P. O'Ibilly, Director U. S. Nuclear Ibgulatory Ormission Ibgion II - 101 thrietta Street, N. W.

Suite 3100 Atlanta, Georgia 30303

Dear Mr. O'Ibilly:

Alabama Power Ompany's response to I.E. Bulletin 79-27 for Farley Nuclear Plant Unit-1 is enclosed.

If you have any qmstions, please advise.

Yours very truly,

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bAM F. L. Clayton, Jr.

FICjr/INE/nnb Enclosure oc: Mr. R. A. 'Ilums Mr. G. F. Trtubridge Office of I&E Divn. of Ibactor Operations Inspection Washington, D. C.

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%e following is a basic description of the power supplies for in -

strunentation and control systms for Parley Nuclear Plant:

%e power supply to instrutentation and control systes consists of four Class lE, channelized inverters, two class lE train-oriented inverters, two Class lE train-oriented batteries and Class lE switchgear and distribution panels.

Each of the four channelized inverters and both of the train-oriented inverters are powered from Class lE 600 volt primary sources with a backup provided by train-oriented batteries so that upon loss of the primary source, an autmatic, uninter-rupted transfer to the backup supply will occur. % e four channelized inverters f

su mly power to four channelized distribution panels. Each of the four channelized distribution panels has a backup power supply from a channelized solatrtn regulator (manual transfer) . %e tw train-oriented inverters supply power to tw train-oriented distribution panels. Both of the train-oriented panels have a backup power supply frun 120-volt, Class lE sources. ,

Tb ensure reliability of indication display, instrutentation (indicators and remrders) is provided with redundant, channels and trains which are electrically isolated and physically separated so that any single failure with a channel or train will not prevent proper operation of the associated function.

We Parley Plant design of instrunentation and control systms is different frm the Oconee Power Station, Unit 3, design in that:

()! Farley does not incorporate an Integrated Control Systs.

(2) We instrumentation associated with the reactor coolant system is part of the nuclear-grade instrunentation system and as such is pro-vided with a Class lE power supply. Syste s associated with decay heat rmoval and water addition to the reactor and steam generators are safety related and their control and instrunentation are provided with Class lE power supplies.

(3) %ere is no non-Class IE inverter supplying power to any control or instrumentation required to function in order to safely shut down the plant, to maintain the plant in hot shutdown, or to proceed to cold shutdown within the limits of the Technical Specification.

We following provides reow to specific questions of IE Bulletin

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79-27:

1. Review the class IE and non-class IE buses supplying power to safety and non-safety related instrunentation and control systems which muld affect the ability to achieve a cold shutdown condition using existing procedures or procedures developed under Its 2 below. For each bus:

(a) identify and review the alarm and/or indication provided in the mntrol rom to alert the operator to the loss of power to the bus.

(b) identify the instrunent and control system loads connected to the bus and evaluate the effects of loss of power to these inaA including the ability to achieve a cold shutdown condition.

(c) describe any proposed design nodification resulting frun these -

, review and evaluations, and your proposed schedule for im-planenting those nodifications.

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RESPO UE:

(a) As in11cated above, there are no Non-Class IE buses supplying power to the instrtmentation and control systans which could affect the ability to achieve a cold shutdown condition in the Parley Plant.

-Each of the four channelized inverters and each of the two train oriented inverters, is provided with an anineter on the Dnergency Power Doard in the control rocan.

' Each of the two train oriented batteries is provided with an anineter

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on the EPB in the control rom.

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-Each of the two train oriented 125V DC switchgears is provided with a bus voltmeter on the EPB in the control roan.

-Each inverter has a dedicated annunciator window on the EPB in the control rocun, to alann a fault condition. .

-Eacn train oriented 125V DC switchgear has a dedicated annunciator window on the BPB in the control rectn, to alarm an undervoltage or a ground fault condition.

-Each train oriented 125V DC switchgear has a dedicated annunciator window on the EPB in the control rocm, to alarm that the corresponding battery breaker is tripped.

In addition, each of the battery chargers associated with the 125V DC switchgears is provided with an anmeter and an annunciator window on the EPB in the control roon, to alarm a fault or disconnected otxidition.

(b) 'Ihe four channelized distribution systans supply power to the following loads:

-Nuclear instrumentation (excore).

-Process control instrunentation

-Padiation nonitoring systan

-acactor protection system

-Main control board instrtunentation

-Waste processing instrtmentation

-Incore thermocouple detection systan

-Auxiliary relays and termination cabinets

-niscellaneous distribution panels.

'Ibe two train-oriented distribution systans supply power to the following loads:

-Hot shutdown panel instrunentation

-Balance of plant instrunentation

-Radiation monitors for containment purge and fuel handling building.

Due to redundancy in the instrunentation and control systans and their associated power supply, loss of one channelized inverter, or train oriented inverter, or of the entire channel or train power supply, will not affect the ability to achieve a cold snutdown condition. 'Ibe same is true in the event of the loss of one 125V DC train.

(c) As a result of the review and evaluation requirrd by this bulletin, it has been concluded that no modifications are required for Farley Nuclear Plant.

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2. Prepare mergency procedures or review existing ones that will be used by control rom operators, including procedures required to achieve a cold shutdown cornition, upon loss of power to each class 1E and non-class lE bus supplying power to safety and .

non-safety-related instrunent and contol systes. 'Ibe mergency procedures should include:

(a) the diagnostics / alarms / indicators /syrtptms resulting frun the review and evaluation oorcucted per item 1 above.

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(b) tne use of alternate indication arx!/or control circuits

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wnich may be powered frun other non-class lE or class IE instrumentation and control buses.

methods for restoring power to the bus.

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(c)

Describe any prrposed design modification or administrative controls to be inpimented resulting frun these procedures, and your proposed schedule for implmenting the changes.

IESPONSE:

Plant instrumentation, as well as associated power sources and procedures required to achieve cold shutdown, have been reviewed for the affects of loss of a class IE bus upon its associated instrutentation panels. 'Ihe review has revealed in significant deficiencies in existing procedures. Some specific annunciation and automatic control functions not essential to achieving cold shutdown are rrarentarily lost or actuated in the event of an inverter failure until the affected instrument pamis can be re-energizea. 'Ihis is acomplished with existing procedures by manually closing tha mechanically interlocked breaker to the alternate power source. Procedures are being revised to speci-fically reflect annunciation and and automatic control functions effected under loss of inverter conditions. Ibvisions are expected to be cxxtpleted by April 4, 1980.

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3. Re-review IE Circular No.79-02, Failure of 120 Volt Vital AC Power Supplies, dated January 11, 1979, to include both class IE and non-class IE safety-related power supply inverters. Based on a review of operating experience and your re-review of IE Circular No. 79-02, describe any proposed design miifications or administrative controls to be inplanented as a result of the re-review.

RESPWSE-Alabama Power Cartpany's response to IE Circular 79-02 and Farley Nuclear

/ Plant, thit.1 operating history have been reviewed and no modifications are necessary.

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