Forwards responses to questions raised during 850321

TENNESSEE VALLEY AUTHORITYCHATTANOOGA, TENNESSEE 374014100 Chestnut Street Tower II

Director of' Nuclear Reactor Regulation Mrh2,18

Attention: Ms. E. Adensam, Chief'Licensing Branch No. 41Division of' Licensing

U.S. Nuclear Regulatory CommissionWashington, D.*C. 20555

Dear Ms. Adensam:

In the Matter of' the Application of' Docket Nos. 50-390Tennessee Valley Authority )50-391

During a March 21, 1985 telephone conf'erence between TVA and NRC representatives,the Staf'f' raised several quest 'ions regarding our previous submiittalsdelineating the f'ire protection program at Watts Bar Nuclear Plant (WBN) .Enclosure 1 contains our response to these concerns. Enclosure 2 contains arevised schedule f'or submittal of' inf'ormation regarding Tcold indication inthe auxiliary control room at WBN. Enclosure 3 contains a statement regardingthe use of' Ruskin f'ire dampers at WBN as discussed between TVA and NRCrepresentatives in the meeting held on March 27, 1985.

If' you have any questions concerning this matter, please get in touch withK. Mali at FTS 858-2682.

Very truly yours,

TENNESSEE VALLEY AUTHORITY

D. E. McCloudNuclear Engineer

.Sworn to ,d subs cr* d bef'ore met Sk d~a y of' 4) 1985.

AN Not;,yK Publ ic

My Commission Expires

Enclosures (3)cc: U.S. Nuclear Regulatory Commission (Enclosures)

Region IIAttn: Dr. J. Nelson Grace, Regional Administrator101 Marietta Street, NW, Suite 2900Atlanta, Georgia 30323

6504010167 850328PDR ADOCK 05000390($O

An Equal Opportunity Employer

RESPONSES TO QUESTIONS RAISED DURING 03/21/85TELCON RE PREVIOUS SUBMITTALS DELINEATING FIREPROTECTION PROGRAM.

2',;. C fvi7o Mu

RECORDS FACILITY BRANCH

NOTICE-THE ATTACHED FILES ARE OFFICIAL RECORDS OF THEDIVISION OF DOCUMENT CONTROL. THEY HAVE BEENCHARGED TO YOU FOR A LIMITED TIME PERIOD ANDMUST BE RETURNED TO THE RECORDS FACILITYBRANCH 016. PLEASE DO NOT SEND DOCUMENTSCHARGED OUT THROUGH THE MAIL. REMOVAL OF ANYPAGE(S) FROM DOCUMENT FOR REPRODUCTION MUSTBE REFERRED TO FILE PERSONNEL.

DEADLINE RETURN DATE

ATTACHMENT 1WATTS BAR NUCLEAR PLANT UNIT 1

FIRE PROTECTIONRESOLUTION OF HIGH-TO-LOW PRESSURE INTERFACE CONCERNS

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i The high/low pressure interfaces are:isolation, excess letdown isolation,head vent isolation. Each interface

RHR suction, pressurizer PORVnormal letdown isolation, andhas been addressed as follows.

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RESIDUAL HEAT REMOVAL (RHR) SUCTION

Power for the RHR shutdown isolation valves, 1-FCV-74-1, -2, -8, and -9 has been removed at the circuit breaker; therefore, spuriousoperation as a result of fire damage to control cables is notpossible. Since these valves are powered by 3-phase 480V ac, spuriousoperation due to fire-damaged power cables between the circuit breakerand the valve motor is not considered credible.

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PRESSURIZER PORV ISOLATION

Reactor coolant system (RCS) pressure control is provided by twoparallel, normally closed, power-operated relief valves (PORVs).These valves are direct solenoid-operated valves which fall closed onloss of power. Power is supplied from an ungrounded do source. EachPORV has a normally open motor-operated block valve in series whichprovides a redundant path for RCS pressure boundary isolation.

The cable routing for the PORVs and block valves has been reevaluatedfor Appendix R separation. The reevaluation shows that adequate(Appendix R, III.G) separation between PORV and block valve cables ismaintained in all areas of the auxiliary building. The reactorbuilding contains two areas where this separation is not maintained:the annulus and the area at the top of the pressurizer where thevalves are located.

As can be seen from Figure 1, the PORV circuit cannot be opened due tofire damage of one cable in the reactor building (cable No. 1V56 14Afor PCV-68-340A, typical for other PORV circuits). If a reactorbuilding fire damages only this cable, then the only possibleelectrical path for the PORV is through either the red or greenindicating light. This electrical path will limit the current (lessthan 50 mA), such that the valve cannot open. Therefore, in order fora PORV to spuriously open and be maintained in the open position, thefollowing events must occur:

1. The fire must be in one of these reactor building areas.

2. The PORV circuit and the circuit of an energized component mustboth be damaged by fire.

3. The PORV circuit and the energized circuit must short together insuch a manner that the PORV becomes energized.

4. This low resistance electrical connection must be maintained,otherwise, the PORV will close.

Since the probability of this event occurring before a line-to-linefault occurs on the energized circuit is extremely low, this event isconsidered to be incredible.

In summary, the reevalution verifies that the postulated fire will notprevent isolation of the RCS pressure boundary at the pressurizerPORV.

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EXCESS LETDOWN ISOLATION

The excess letdown path creates a high-low pressure interface betweenthe reactor coolant system and the chemical and volume control system.The excess letdown line is a 1-inch line off of reactor coolant coldleg 3. The excess letdown flowrate is approximately 50 gal/min. Withthis base rate, assuming no makeup, the pressurizer level will dropfrom the no-load pressurizer level to the low level set point in about23 minutes and will empty the pressurizer in about 74 minutes.

The excess letdown line contains three valves in series which are ableto isolate the flow path. Two of the valves (FCV-62-54 and FCV-62-55)are fail closed air-operated valves. The third valve (FCV-62-56) isan air-operated modulating valve. All three valves are located insidecontainment upstream of the excess letdown line penetration isolationvalve FCV-62-61.

A disconnect switch has been added to the battery board which suppliespower to 1-FCV-62-54. This switch will override any spurious opensignals which result from fire-damaged control cables. The valvesolenoid is powered from an ungrounded dc supply. Fire damage to thesolenoid power cable should result in a short to ground which willblow a fuse, de-energize the circuit, and close the valve.

A cable fault which energizes the solenoid and opens the valve is veryunlikely in an ungrounded power system. In order to energize thecircuit, a cable fault must occur which aligns the positive conductorin the solenoid cable to the positive conductor in an adjacent cablerouted in the same tray or conduit where the adjacent cable originatesat the same board. If the adjacent cable originates from a differentboard, then a positive-to-positive and negative-to-negative alignmentis required. The probability that this event will occur before thecircuit shorts to ground and blows a fuse is very low and is notconsidered to be credible. The probability that such a fault willprevent excess letdown isolation due to fire-damaged cables becomesmuch lower when it must occur on not only one, but three valvecircuits.

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NORMAL LETDOWN ISOLATION

The normal letdown path creates a high-low pressure interface betweenthe reactor coolant system and the chemical and volume control system.The letdown line is a 3-inch line off of reactor coolant cold leg 3.The letdown flowrate is normally 75 gal/min. With the loss rate,assuming no makeup, the pressurizer level will drop from the no-loadpressurizer level to the low-level set point in about 15 minutes andwill reach the 0-percent level in about 49 minutes.

The normal letdown line contains three sets of valves which are ableto isolate the flow path. Valves FCV-62-69 and FCV-62-70 are inseries, and if either one closes, the letdown path will be isolated.Additionally, if the letdown orifice isolation valves (FCV-62-72, -73,-74, and -76) close, the letdown path will be isolated. All of thevalves are fail closed air-operated valves.

To ensure that at least one valve can be closed, a disconnect switchhas been added to the battery board which supplies power to thesolenoid which controls 1-FCV-62-69. This switch will override anyspurious open signal caused by fire-damaged control cables. The valvesolenoid is powered from an ungrounded dc supply. Fire damage to thesolenoid power cable should result in a short-to-ground which willblow a fuse, de-energize the circuit, and close the valve.

A cable fault which energizes the solenoid and opens the valve is veryunlikely in an ungrounded power system. In order to energize thecircuit, a cable fault must occur which aligns the positive conductorin the solenoid power cable to the positive conductor in an adjacentcable routed in the same tray or conduit, where the adjacent cableoriginates at the same board. If the adjacent cable originates from adifferent board, then positive-to-positive and negative-to-negativealignment is required. The probability that this event will occurbefore the circuit shorts to ground and blows a fuse is very low andis not considered credible. The probability of such a faultpreventing letdown isolation becomes much lower when it must occuron not only one valve fault, but three.

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HEAD VENT ISOLATION

The reactor vessel head vent valves create a high-low pressureinterface between the reactor coolant system and the pressurizerrelief tank. The head vent system has 1-inch lines with two sets ofparallel isolation valves. The interface between the head vent systemand the reactor coolant system has a 3/8-inch orifice which furtherreduces the flowrate. The orifice limits the flow to 17.5 lbm/sec.The isolation valves and piping resistance will reduce the actualflowrate to less than 17.5 lbm/sec. Assuming a loss rate of 17.5lbm/sec with no makeup, the pressurizer level would decrease from theno-load level to the low-level set point in 5-minutes and 0-percentlevel in 17 minutes.

The head vent valves are direct solenoid-operated valves which failclosed on loss of power. The power source is an ungrounded dc supply.A disconnect switch has been added to both battery boards which supplypower to the head vent valves. Switch 1-SW-68-394 will disconnectpower and close valves 1-FCV-68-394 and -397. Switch 1-SW-68-395 willdisconnect power and close valves 1-FCV-68-395 and -396.

These switches will override spurious open signals which result fromfire-damaged control cables.

Fire damage to the solenoid power cable should result in a short-to-ground which will blow a fuse and de-energize the circuit causing thevalve to close. A cable fault which energizes the solenoid and opensthe valve is very unlikely in an ungrounded power system and is notconsidered credible. The probability that a cable fault such as thiswill prevent head vent isolation becomes much lower when it must occuron not only one but two valve circuits.

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FIGURE I

* LOCATED IN UNIT CONTROL ROOM

,I LOCATED IN AUXILIARY CONTROL ROOM(AUXILIARY CONTROLWITH REDUNDANT FUSES NOT SHOWN)

I 1-PNL-278- M5/A

RBC6 (BK) C7-4C NO. IRBC7 (W) IV5610ARBC8 (R)RBCPI (G)

N 7

I-PNL- 278 - LI IA

C+

XS-68-340CNOR

1-4C NO. 14?~-IV5612A

RBCN (BK)RBC2RBC3RBC12

(W)(R)(G)

IELECTRICAL PENETRATION

c

FSV- 68-340A

REACTORBLDG

-. - - -- - I

SIMPLIFIED PORV POWER CKT(PCV-68-340A SHOWN) '

'-4- IC NO. 14IV5613ARBCNRBC2RBC3RBC12

J-BOX

'-4-IC NO.14IV5614ARBCNR BC2RBC3RBC12

i6E I-FSV-68-340A_ I

(NORMAL POWER- CONTROLFROM MAIN CONTROL ROOM)

XS-68- 340CNOR

- -

I

I

I

I

I

I

I

-

...


FIRE PROTECTIONOPERATOR ACTIONS OUTSIDE OF THE MAIN CONTROL ROOM

WHICH MAY BE REQUIRED TO RESPOND TO A FIRE

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Appendix A of enclosure 2 of the January 25, 1985, fire protectionsubmittal, "Operator Actions," has been replaced with tables whichidentify all operator actions located outside the main control room(MCR) which may be required for shutdown from the MCR. The timesbefore the actions are required and the length of time required toperform the actions are listed to ensure that the seven availableoperators can perform all required actions. Accordingly, attachment 2is provided as a replacement for Appendix A of enclosure 2 of theJanuary 25, 1985, fire protection submittal.

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APPENDIX A

OPERATOR ACTIONS PERFORMEDOUTSIDE THE MAIN CONTROL ROOM

FOR HOT SHUTDOWN

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Safety Function

RCS pressure boundary control

RCS makeup

RCP seal injection

RCS pressure control

Reactivity control

SG inventory control

SG pressure control (manual)

SG isolation

Containment integrity

Onsite electrical

HVAC

When Required

Before pressurizer low level

When cooldown begins

1 hour after lost

Before high or low RCS pressure

When decision is made to shut down

10 minutes after decision is madeto shut down

2 hours after seal injection starts

Before SG low pressue or level

At all times

At all times

Before high temperatures reached

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OPERAT(

Action

RCS Pressure Boundary Control

1. Isolate normal letdown

2. Isolate excess letdown

RCS Makeu /RCS Seal Injection

1. Realign ERCW to CCS Hx

2. Supply A train ERCW to Btrain diesel

3. Al ign CCSP B-B to the Btrain header

4. Reopen valve to CCS Hx-A

5. Clean ERCW strainers

6. Establish charging path

7. Establish CCP suction

8. Stop CS pumps

9. Stop RWST from drainingto cont sump

10. Vent VCr

(Manual action only for arequired. This action is

Component

SW-62-69

SB-62-54

1-FCV-67-2232-FCV-67-2231-PCV-67-458

FCV-67-65FCV-67-125/126

1-FCV-70-26/27/64/74/341-70-705

1-FCV-67-47 8

FCV-67-9A/1OA

62-526 or 62-537

LCV-62-135/ 136LCV-62-13 2/133FCV-63-6/ 7

HS-72-IOCHS-7 2-27C

FCV-72-20/21FCV-74-3/ 21

62-692/693

Location

Battery board room I

Battery board room II

Mezzanine above CCS Hx

Diesel generator buildingCS Hz room

Mezzanine above CCS pumps

Inlet to CCS Hz

intake pumping station

CCP pump rooms

El 692 - penetration roomVCT roomEl 692 pipe chase

6.9kV S/D Bd

El 676 pipe chaseRBP pump room

El 692 penetration room

Required Perform

15 min

15 min

1 hr

15-20 hrs

1 hr

1 hr

15-20 hrs

1 hr

1 hr

10 min

30 min

24 hrs

3 min

3 min

30 min

'15 min

30 min

15 min

1 hr

15 min

20 min

3 min

15 min(2 operators)

30 min

fire on LCV-62-132/133. With a fire at this location, no other normal action isnot included in the operator time study.)

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)NS

OPERAT

ActionRCS Pressure Control

1. Turn off pressurizer heaterwhich is spuriously on

2. Stop pressurizer auxiliaryspray

Reactivity Control

1. Stop control rod M-G sets

(Manual action only if fireThis action is not included

2. Stop boron dilution

MDAFWP

1. MDAFWP - open backpressure control valve

2. Open LCV

3. Manually throttle SG level

TDAFWP

1. Control pump

2. Control LCV

Both

1. Open ERCW supply

Component

XS-68-341XS-6 8-3 41FHS-6 8-3 41DCH S-6 8-3 41AC

FCV-62-90/ 91

Location

6.9 kV S/D BD

Pipe chase - el 713

Required Perform

30 min

20 min

3 min

10 min

480V unit bods Turbine building When decision is made toshutdown

on RT breakers with a fire at this location, no other manual actions are required.in the operator time study.)

81-533 Pipe chase - el 713 1 hr 15 min62-934 Penetration rm - el 713 (2 operators)

PCV-3-122/132

LCV-3-156/164/148 or 171

3-828/836/827, etc.

L-3 81

LCV-3 -17 4/173/17 2/17 5

FCV-3 -116 A/BFCV-3 -136A/BFCV-3-126A/BFCV-3-179A/ B

At MDAFWP

Valve station

Valve station

At TDAFWP

Valve station

At AFW pumps.

10 min*

10 min

30 min

10 mint

10 mint

6 hrs

10 min

10 min

Continuously

Continuously

Continuously

15 min

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INS

OPER AS

Action Component Location Required PerformSG Pressure Control

1. Throttle ADVs PCV 1-5/12/23/30 Stm valve rms 3 hrs Continuously

*10 minutes after decision is made to shut down which is when the reactor will be tripped causing main feedwater tobe isolated.

SG Isolation

No manual actions

Containment Intesrity

1. Stop air return fans Trip breaker 480V S/B bd rms 10 min 3 min

Onsite Electrical

1. Alternate power supply to Spare chargers 1-S and Electrical Bd rms el 772 2 hrs 10 minbatteries 2-S

2. Man DG building Door DG Building NA Continuously

HVAC

1. Monitor temp in 480V 480V auxiliary building Electrical board room 2 hr 10 mintransformer room and common board el 772reduce load and turn offlights

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OPERATOR REQUIREMENTS

0-20 Minutes

Operate TDAFW pumpOperate SG level control valvesIsolate normal and excess letdownStop auxiliary sprayStop air return fansStop CS pumpsMan DG building

1111111

operatoroperatoroperator-operatoroperatoroperatoroperator

ContinuouslyContinuously3 minutes10 minutes3 minutes3 minutesContinuously

0-30 Minutes

1-3. Continuously manned stations4. Turn off pressurizer heaters

Stop boron dilution (close 81-533)5-6. Stop RWST drain through sump lines7. Stop boron dilution (close 62-934)

3 operators1 operator


Continuously15 minutes

15 minutes15 minutes

0-1 Hour

1-3. Continuously manned stations4. Align 2A header to CCS heat

exchanger A*Align CSP 1B-B to CCS B-header*

5. Reopen 1-FCV-67-4786. Establish charging path7. Establish CCP suction


111

operatoroperatoroperator

Continuously30 minutes

30 minutes15 minutes15 minutes20 minutes

0-2 Hours

Continuously manned stationsRealign battery power supplyMonitor 480V transformer roomtemperature

311

operatorsoperatoroperator

Continuously10 minutes10 minutes

0-3 Hours

1-3. Continuously manned stations4-5. Control SG ADV

3 operators2 operators

ContinuouslyContinuously

More than 3 Hours

1-5.6a.6b.7.

Continuously manned stationsClean ERCW strainersRealign DG ERCW supplyOpen ERCW supply to AFW pump

5111

operatorsoperatoroperatoroperator

Continuously15-20 hours15-20 hours6 hours

*Mutually exclusive actions

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1 .2 .3.-

45.

6 .7.

1-3.4.5.


FIRE PROTECTIONDISCUSSION OF TVA'S POSITION ON THE

POTENTIAL SPURIOUS OPERATION OF 3-PHASE CIRCUITS

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NRC Concern

How did TVA evaluate the 3-phase ac circuits in the type II associatedcircuits analysis?

TVA Response

A 3-phase ac circuit is not a potential type II associated circuit ofconcern. A de-energized, 3-phase component cannot adversely affectsafe-shutdown of the plant by spurious operation unless the followingoccurs:

a. the circuit of the de-energized component and the circuit of anenergized component must both be damaged by fire,

b. subsequently, shortened together in such a manner that the de-energized circuit becomes energized.

The probability of this occurring before a phase-to-phase fault occurson the energized circuit is extremely low and, consequently,considered to be incredible.

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FIRE PROTECTIONRESPONSES TO CONCERNS IDENTIFIED DURING THE MARCH 21, 1985,

TELECON WITH NRC

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Provided below are the NRC concerns identified to TVA during a March 21,1985, telecon and TVA's responses to the concerns.1. NRC Concern

TVA should identify all high-to-low pressure interfaces anddescribe the design features, analyses performed, or actionstaken to ensure that spurious operation will not result in a LOCAthrough those interfaces.

TVA Response

Attachment 1 provides the response to this concern.

2. NRC Concern

TVA should provide a commitment to remove power from one of theresidual heat removal (RHR) high-pressure interface valves in eachflow path to ensure that a LOCA as a result of spurious operationcannot occur.

TVA Response

As discussed in attachment 1, TVA has removed power from one ofthe valves in each flow path.

3. NRC Concern

Provide a listing of operator actions which may be required torespond to a fire.

TVA Response

Potential operator actions required to respond to a fire arelisted in attachment 2.

4. NRC Concern

TVA should indicate that for Watts Bar Nuclear Plant (WBN) thereare no type III associated circuits with common enclosures oridentify such and the actions taken to resolve problems identifiedwith these circuits.

TVA Response

The results of the type I and type III circuit analyses andactions taken to resolve any potential problems which wereidentified are contained in attachment 6. Attachment 6-2 liststhe type III associated circuits of concern that were identifiedin the WBN Appendix R types I and III associated circuit analysis.These circuits were previously incorrectly identified as type Iassociated circuits of concern in TVA's March 5, 1985 submittal toRegion II.

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5. NRC Concern

Identify the systems which can be controlled from the auxiliarycontrol room (ACR) to mitigate the consequences of a fire.

TVA Response

All the safety functions provided when shutdown is conducted fromthe MCR are available for shutdown from outside the MCR. Listedbelow are the safety functions and the systems and/or componentsused to provided the functions.

Safety Function Systems and/or Components

RCS pressure boundary control

RCS makeup/seal injection

RCS pressure control

Reactivity control

SG inventory control

SG pressure control

SG isolation

Containment integrity

Onsite electrical supply

HVAC

Control of all components whichconstitute high/low pressureinterfaces.

CVCS charging for RCS makeup andseal injection.

Pressurizer heaters andpressurizer spray

Reactor trip prior to MCRabandonment. Source rangemonitor in ACR.

Motor-driven and turbine-drivenAFW pumps and LCVs. Automaticswitchover from CST to ERCW.

Safety valves and control ofrelief valves.

Main steam isolation and bypassvalves, main feedwater isolationvalves, and blowdown isolationvalves.

Purge air system.

Shutdown power systems-.

DG building ventilation, pumproom ventilation, containmentcooling.

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6. NRC Concern

Provide a listing of those valve handwheels which are locked andare subject to operator handwheel operation.

TVA Response

The following list of valves required for manual operation arelocked in the open position. Only one valve of each pair isrequired to be throttled.

1-3-826 or 1-3-8341-3-827 or 1-3-8351-3-828 or 1-3-8361-3-829 or 1-3-837

These valves are manual isolation valves immediately upstream ordownstream of MDAWP LCVs. The operating time specified in thetime study for operation of these manual valves is 30 minutes.

7. NRC Concern

Indicate what actions, if any, the operators must take to alignthe inlet and outlet valves of the boron injection tank (BIT) inthe event of a fire (key 6 of the shutdown logic).

TVA Response

The intended function of this key is to provide a flow path forsupplying RCS makeup. The function of the BIT is not required.

There are no fires for which credit was taken for supplying RCSmakeup through the ECCS charging path. However, pages 14, B2, andD1 of attachment 2 have been revised to reflect the presentdesign. Since the unit 2 design has not been changed to removethe BIT, the contents of the key will remain unchanged with a notedescribing the unit 1 configuration. This is consistent with TVAdesign documentation.

Revised pages 14, B2, and D1 are provided in attachment 5.

8. NRC Concern

Pages 22 and 25 of attachment 2 to the January 25, 1985, submittalindicate that if a train B pump is required to respond to a firethen train B power will have to be evaluated. Clarify whether theevaluation has been performed.

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TVA Response

The note concerning the use of the B train pumps was included toensure that those performing the interaction analysis would reviewall B train cables in any interaction in which credit was takenfor using a B train pup. For those cases where B train equipmentwas required, the availability of B train power was evaluated.The note on page 22 of attachment 2 to the January 25, 1985,submittal has been revised and revised page 22 is provided inattachment 5.

9. NRC Concern

Indicate how circuits with the potential for spurious operationswere treated.

TVA Response

Circuits with the potential for spurious operations were addressedin the following manner:

(1) For the most part, circuitry for equipment which was to beprevented from spurious operation was treated as requiredcircuitry. Accordingly, TVA elected to protect thiscircuitry in accordance with section III.G.2 of 10 CFR 50,Appendix R. Actions taken to protect specific circuits areaddressed in Attachment 4 to the enclosure to J. W. Hufham'sJanuary 25, 1985, letter to E. Adensam.

(2) For some Type II circuits, operator actions have beenimplemented to mitigate the effects of the postulatedspurious operation. A listing of the necessary operatoractions outside the main control room is provided asAttachment 2 to this memorandum. In addition, these actionsare identified in Attachment 2 to the enclosure to theJanuary 25, 1985, letter referenced above.

(3) Other circuits were analyzed not to require the protectiondescribed in part (1) above and not to require the manualoperator actions discussed in part (2) due to thesignificantly low probability that a spurious operation ofthe equipment in questions could occur. These circuitsincluded ungrounded dc circuits, ungrounded ac circuits,and three-phase circuits. Based on discussions with NRCrepresentatives during the March 25, 1985, meeting inBethesda, Maryland, this approach was approved for allcircuits of this type except for high-low pressure interfacevalves. TVA has specifically addressed the high-lowinterface valves and the three-phase circuits in Attachments1 and 3, respectively. The ungrounded circuits are discussedin Attachment 4 of the enclosure to the January 25, 1985,letter. In addition, an informal copy of an index locatingeach ungrounded circuit in the Reevaluation Report wasprovided to NRC during the March 25 meeting.

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(4) Finally, certain circuits were identified as "required" inAttachment 2, of the Reevaluation Report; however, upon afunctional analysis of the equipment affected, it wasdetermined that protection or manual action was not required.Final evaluations of circuits of this nature were discussedin Attachment 4 of the Reevaluation Report. Locations ofthese circuits in the report were provided in theaforementioned index.

10. NRC Concern

Clarify whether heating, ventilating, and air-conditioning(HVAC) systems are required for cooling during/after a fire. Ifthey are not, provide a discussion of the basis for not needingHVAC.

TVA Response

An evaluation has been performed to ensure that acceptabletemperatures will be maintained for 72 hours in all areas listedin attachment 2 for which HVAC is stated as not being requiredfor safe shutdown. The following pages from enclosure 2 to ourprevious submittal have been revised to reflect this: pages 78,83, 84, 85, 86, 87, 88, 96, 98, 101, 102, and B7. The revisedpages are provided in attachment 5.

11. NRC Concern

The note on page 66 of enclosure 2 to the January 25, 1985,submittal indicates that RHR valves can be required. Pleaseclarify.

TVA Response

The note contains a typographical error. The word "required"should be "repaired." Attachment 5 provides a revised page 66correcting this error.

12. NRC Concern

On page 89, the note indicates that the ice condenser doors willbe opened. Is this a manual or automatic action and is itrequired for containment cooling?

TVA Response

The ice condenser system is not requird to provide containmentcooling for safe shutdown. The option for opening the icecondenser doors was added as an enhancement should containmentcooling be lost. The note addressing opening the ice condenserdoors has been deleted. Pages 89, 90, 94, and 95 have beenrevised and are provided in attachment 5.

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13. NRC Concern

Page 107 of enclosure 2 to the January 25, 1985, submittalindicates that portable fans may be used for cooling of RHR pumprooms. Please indicate how these fans will be powered.

TVA Response

WBN has the following equipment available for providingventilation to the RHR pump rooms in the event that normalventilation is lost:

1. Two 10,000 cfm air movers suitable for connection withexisting outlets in the area of the pump rooms. Appropriateoutlets are installed within 30 feet of all pump room doors.

2. Two 100-foot extension cords appropriate for use with theabove fans.

3. Portable generators appropriate for use with the above fans.

4. Eighty feet of flexible duct appropriate for use with theabove fans.

14. NRC Concern

In many cases, your submittal refers to actions which operatorsmust verify. Are these required to prevent/determine if spuriousoperations have occurred?

TVA Response

Many of the actions to verify the position of valves, etc.,discused in Appendix A to enclosure 2 of the January 25, 1985,submittal were not required to mitigate a fire. To address thisconcern, Appendix A has been revised. Attachment 2 provides arevised Appendix A which only lists those actions which arerequired outside the MCR.

15. NRC Concern

Please indicate how boron addition/concentration is controlledduring the transfer from the main to the auxiliary control room.

TVA Response

Boration control is not required during control room abandonmentuntil control is established in ACR (timeframe 10-15 minutes) dueto the insignificance of dilution on the degree of negataivereactivity inserted by the control rods (control and shutdown).A review of FSAR Table 15.2-1 indicates that approximately 4400seconds are available from the time of trip before a loss ofshutdown margin as result of dilution would occur.

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16. NRC Concern

Indicate what method was used to identify associated circuits(i.e., computer-generated list, drawing review, etc.).

TVA Response

A manpower intensive drawing review was performed on the WBNelectrical systems, to identify the Appendix R types I and IIIassociated circuits of concern. Type II associated circuits wereidentified by a systems review to determine those componentswhose maloperation could affect safe shutdown.

17. NRC Concern

Clarify whether the switchover of the auxiliary feedwater (AFW)suction from the condensate storage tank (CST) to the essentialraw cooling water (ERCW) system is manual or automatic (referencepage 4 of Appendix D to attachment 2, key 19).

TVA Response

When shutdown during a fire is conducted from the MCR, transferof the AFW pump suction from the CST to the ERCW system may bedone by manually opening the isolation valves to the operatingpump. When shutdown is conducted from the ACR due to a fire inthe control building, transfer switches (located in the 480Vreactor MOV boards) are positioned to transfer control from theMCR to the MOV boards in the auxiliary building. The transferswitches isolate the auxiliary control circuit from the controlbuilding with open switch contacts. Therefore, the capabilityfor automatic switchover from the CST to the ERCW system will notbe affected by a fire in the control building. This subject wasalso addressed in enclosure 1 of our letter dated March 21, 1985.

Page B4 has been revised to clarify the description of transferof AFW pump suction and is provided in attachment 5.

-8-


FIRE PROTECTIONREVISED PAGES OF ENCLOSURE 2 TO THE JANUARY 25, 1985,

FIRE PROTECTION SUBMITTAL

-1-

WATTS BAR NUCLEAR PLANTKEY 6 (Operation List)

(This key was not used during shutdown analysis)

*FCV-63-25)

*FCV-63-26)

*FCV-63-39)*FCV-63-40)

FCV-63-41)

FCV-63-42)

Either one

Either one

Either one

Must Open/Remain OperableMust Open/Remain Operable

Must Open/Remain OperableMust Open/Remain Operable

Must CloseMust Close

*An inlet and an outlet valve for the BIT must open and one of these will berequired to throttle the flow to the RCS.

NOTE: On unit 1, the BIT inlet valves, FCV-63-39 and FCV-63-40 are normallyopen with power removed. The valves in the line from the boric acidtank, FCV-63-41 and FCV-63-42 are normally closed with power removed.

E14214.01NEB - Mar. 28, 1985

'4


(This key was not used during shutdown analysis)

RCP Thermal Barrier Booster Pump A-A)*RCP Thermal Barrier Booster Pump B-B)CCS Pump A-A) Either one

*CCS Pump B-B)

Either one

ERCW Header A (Operation List) (See Key 1)

FCV-67-146

1-FCV-67-223)2-FCV-67-223)1-FCV-67-458)

FCV-70-143) Either oneFCV-70-85 )

**Instrument loop 1-L-70-63A (for 1-LI-70-63A)**Instrument loop 2-L-70-63A (for 2-LI-70-63A)**Instrument loop 1-L-70-99A (for I-LI-70-99A)**Instrument loop 2-L-70-99A (for 2-LI-70-99A)

Must Operate

MustMustMust

OpenOpenClose

Must CloseMust Close

Anyone

MustMustMu stMu st

*If the train B pumps are used, the B-power supply must be availablepower distribution, B diesel generators, and train B ERCW cooling).

**Included are associated process variable sensing lines..

OperateOperateOperateOperate

E14214.01

(i.e., B-

NEB - Mar. 28, 1985

MustMustMustMust

OperateOperateOperateOperate

I


Path 1

RHR Pump A-A*FCV-67-146*FCV-70-156

Must OperateMust OperateMust Open

Path 2

RHR Pump B-B*FCV-67-152*FCV-70-153

Must OperateMust OperateMust Open

Component cooling and ERCW supplies are assured for RHR cooling requirements. Thesame CCS and ERCW components used to achieve and maintain hot standby may be used forRHR system cooling while taking the plant to cold shutdown.

*Handwheel operation acceptable.

NOTE: Valves FCV-67-146 and FCV-67-152 may be repaired if the fire was on the Ivalve.

E14214.01NEB - Mar. 28, 1985

WATTS BAR NUCLEAR PLANTKEY 37B

HVAC APPENDIX R REVIEWAUX. INSTRUMENT ROOMS AIR CONDITIONING

(USING ELEC. BOARD ROOM CHILLERS)

Auxiliary Instrument Room air conditioning is not required for 72 hoursfollowing a fire per EN DES Calculation TI-ECS-96 (NEB 850116 235).

E14214. 01NEB - Mar. 28, 1985

7ab

WATTS BAR NUCLEAR PLANTKEY 37D

Steam Valve Vault Ventilation System

Operation of the main steam valve vault ventilation system is not required72 hours following a fire per EN DES Calculation TI-ECS-96 (NEB 850116 235).

E14214. 01NEB - Mar. 28, 1985

I

WATTS BAR NUCLEAR PLANTI KEY 37E

Shutdown Board Room Air ConditioningElevation 757

Equipment Needed for Plant Shutdown Following a Fire

Shutdown Board Room air conditioning is not required for 72 hours following afire per EN DES Calculation TI-ECS-96 (NEB 850116 235).

E14214.01NEB - Mar. 28, 1985

WATTS BAR NUCLEAR PLANTKEY 37F

480V BOARD ROOMS AND BATTERY BOARD ROOMS

Cooling to the 480V Board Room and Battery Board Rooms is not required for 72hours following a fire.

E14214.01NEB - Mar. 28, 1985

WATTS BAR NUCLEAR PLANTKEY 370

10CFR Appendix R HVAC ReviewCable Spreading Room

Ventilation for the Cable Spreading Room is not required for 72 hours followinga fire per EN DES Calculation TI-ECS-96 (NEB 850116 235).

E14214. 01NEB - Mar. 28, 1985

WATTS BAR NUCLEAR PLANTKEY 37H

PRESSURIZER HEATER TRANSFORMER ROOMEL 782

1OCFR50 APPENDIX R REVIEW

Pressurizer Heat Transformer Room air 'conditioning is not required for 72 hoursfollowing a fire per EN DES Calculation TI-ECS-96 (NEB 850116 235).

E14214. 01NEB - Mar. 28, 19858e

WATTS BAR NUCLEAR PLANTKEY 37I

Intake Pumping StationDrawing Ref: 37W900-1R3

Intake Pumping Station ventilation is not required for 72 hours following a fireper EN DES Calculation TI-ECS-96 (NEB 850116 235).

NEB - Mar. 28, 1985

I

E14214.01

WATTS BAR NUCLEAR PLANTKEY 37J

Appendix R ReviewContainment Cooling System

Spurious and Operation List

This Set Must operate or the Set on the Following Page Must Operate:

L.C. air handling unit fan-AInstrument loop 30-74

L.C. air handling unit fan-CInstrument loop 30-77

CRDM air handling unit fan-AInstrumient loop 30-83Instrument loop 30-84Instrument loop 30-85TCO 30--84TSV 30--84TCO 30--85TSV 30-85

CRDM air handling unit fan-CInstrument loop 30-88Instrument loop 30-89Instrument loop 30-90TCO 30--89TSV 30--89TCO 30--90TSV 30--90

Must RunMust Function


MustMu stMustMu stMustMustMu stMust

RunFunctionFunctionFunctionNot CloseNot EnergizeNot OpenNot Energize

Must RunMust FunctionMust FunctionMust FunctionMust Not CloseMust Not EnergizeMust Not OpenMust Not Energize

NOTE: Key 37J equipment is required only when the auxiliary control room is inuse.

E14214,01

El

ItU

NEB - Mar. 28, 1985


Appendix R ReviewContainment Cooling System

Spurious and Operation List

This Set Must Operate or the Set on the Preceding Page Must Operate:

L.C. air handling unit fan- BInstrument loop 30-75

L.C. air handling unit fan-DInstrument loop 30-78

CRDM air handling unit fan-BInstrument loop 30-92Instrument loop 30-93Instrument loop 30-94TCO 30-93TSV 30-93TCO 30-94TSV 30-94

CRDM air handling unit fan-DInstrument loop 30-80Instrument loop 30-81Instrument loop 30-82TCO 30-81TSV 30-81TCO 30-82TSV 30-82



Must

Mu stMu stMustMust

Mus tMus t

MustMustMus tMustMu s tMustMus tMust

NOTE: Key 37J equipment is required only when the auxiliary contuse.

E14214,.01

Function

Function

FunctionNot closeNot EnergizeNot OpenNot Energize

RunFunctionFunctionFunctionNot CloseNot EnergizeNot OpenNot Energize

rol room is in

NEB - Mar. 28, 1985


ERCW to Lower Compartment Coolers & CRDM Coolers

Path 1 (Train A)

ERCW Hdr A (Operation List) (See Key 1)

*FCV-67-83

TCV-67-84TCV-67-85

*FCV-67-87*FCV-67-88*FCV-67-91TCV-67-92TCV-67-93

*FCV-67-95*FCV-67-96

Mu stMu stMus tMustMustMustMus tMustMustMust

Not

NotNot

NotNotNot

NotNotNotNot

Close/Remain OperableCloseClose

Close/RemainClose/RemainClose/Remain

CloseCloseClose/RemainClose/Remain

ERCW Hdr 1A (Spurious List) (see Key 1) (Unit 1)

ERCW Hdr 2A (Spurious List) (see Key 1) (Unit 2)

*These valves will close on a spurious phase B containment isolation signal.They will be required to be reopened.


NEB - Mar. 28, 1985Q~4

OperableOperableOperable

OperableOperable

II

E14214, 01

WATTS BAR NUCLEAR PLANT

KEY 37JERCW to Lower Compartment Coolers & CRDM Coolers

Path 2 (Train B)

ERCW Hdr B (Operation List) (See Key 1)

*FCV-67-99TCV-67-100TCV-67-101

*FCV-67-103*FCV-67-104*FCV-67-107TCV-67-108TCV-67-109

*FCV-67-111

*FCV-67-112

Must

MustMustMustMustMustMustMustMust

Must

NotNotNotNotNotNotNotNotNot

Not

Close/Remain OperableCloseCloseClose/Remain OperableClose/Remain OperableClose/Remain OperableCloseCloseClose/Remain OperableClose/Remain Operable

ERCW Hdr lB (Spurious List) (See Key 1) (Unit 1)

ERCW Hdr 2B (Spurious List) (See Key 1) (Unit 2)

*These valves will close on a spuriousThey will be required to be reopened.

phase B containment isolation signal.


NEB - Mar. 28, 1985E14214.01

WATTS BAR NUCLEAR PLANTKEY 37K

480V Transformer Room VentilationEl 772 auxiliary building

If cooling is lost to 480V transformer room 1A, and room temperature exceeds1040 F, the operators must begin removing loads from the 480V auxiliarybuilding common board transformer and turn off lighting in transformer room 1Ato maintain room temperature below 1220F. If cooling is lost to 480Vtransformer rooms 2A, 1B, or 2B, the equipment in the rooms is capable ofwithstanding the resulting temperature for at least 72 hours.

NEB - Mar. 28, 1985E14214.01

WATTS BAR NUCLEAR PLANTKEY 37M

Penetration Room Coolers

Penetration Room cooling is not required for 72 hours following a fire per IEN DES Calculation TI-ECS-96 (NEB 850116 235).

NEB - Mar. 28, 1985E14214.01

WATTS BAR NUCLEAR PLANTKEYS 370 & 37P

BORIC ACID TRANSFER PUMPS AND AFW PUMP COOLERS,

CCS AND AFW COOLERS, AND SFP AND TB SPACE COOLERS

BA Transfer Pumps and AFW Pumps space coolers, CCS and AFW Pumps space coolers,and SFP and TB Booster Pumps space coolers are not required for 72 hoursfollowing a fire per EN DES Calculation TI-ECS-96 (NEB 850116 235).

E14214. 01 NEB - Mar. 28, 1985

\0\

I

WATTS BAR NUCLEAR PLANT

KEY 37QPIPE CHASE COOLERS

Pipe Chase cooling is not required for 72 hours following a fire per EN DES ICalculation TI-ECS-96 (NEB 850116 235).

NEB - Mar. 28, 1985E14214.01

Key 5

The long-term water source for RCS makeup and RCP seal injection (if used) isthe RWST. It may be aligned by opening either FCV-62-135 or FCV-62-136. TheVCT will continue to supply makeup water for a sufficient time after letdownlines are isolated that credit may be taken for handwheel operation of thevalves. VCT level is also provided to allow the operator to turn the CCP offto prevent damage. These valves, however, are not adequately separated andone postulated fire may render both valves inoperable. Therefore analternate path is provided through the inlet piping for the SI pumps and backto the inlet to the CCPs. If this flowpath is used, one of two inlinevalves, FCV-63-6 or FCV-63-7, must be opened. Sufficient NPSH is providedfor the CCPs based upon the calculations in reference (NEB 841206 218).

This key also identifies the equipment whose spurious operation would divertflow from the RCS makeup flow path. This includes preventing the containmentspray and RHR spray systems from actuating.

Key 6

The ECCS flow path is the safety-grade path for RCS makeup. It may be usedif the normal charging path becomes isolated. To provide the flowpath aninlet and an outlet valve for the boron injection tank (BIT) must be opened.One of these valves will be required to be manually controlled (open orclosed) to throttle the flow to the RCS. On unit 1, the BIT inlet valves arenormally open with power removed and the valves in the line from the boricacid tank are normally closed with power removed.

Key 7

For RCS pressure boundary isolation, the normal letdown path must beisolated. This requires the closure of FCV-62-69, FCV-62-70, or all four ofthe regenerative heat exchanger outlet valves.

In all cases the RHR letdown line must remain isolated until the RHR systemis required for bringing the the plant to cold shutdown.

The RVHVS solenoid values must remain closed to prevent the depressurizationof the RCS.

Key 8

To further ensure RCS pressure boundary control the excess letdown lines mustbe isolated. This requires closing FCV-62-54, FCV-62-55, or FCV-62-56.

E54270.03NEB - Mar. 28, 1985{32 -

Key 13

This key contains the equipment necessary to supply control air for thosefunctions on the shutdown logic diagram which require it for operation. Path1 contains the components required for auxiliary air compressor A whichprovides control air for air supply leader A. Path 2 contains the equipmentfor air supply header B.

Keys 14 & 15

The turbine driven AFW pump may be used to supply feedwater for SG inventorycontrol. If this pump is used (as opposed to a motor driven pump, key 11),the SG level control valves (key 16) corresponding to the two loops beingused for cooldown must be operable.

For purmp operation, a steam supply from SC 1 or 4 must be available. Inaddition, the turbine trip and throttle valve and governor valve must beoperable.

Key 16

If the turbine driven AFW pump is used to supply feedwater to the SGs, thetwo level control valves corresponding to the loops being used for cooldownmust be operable. The valves may be controlled manually. Manual controlconsists of handwheel operation of the LCV. The manual method of maintainingSG level requires monitoring in the MCR with the wide range level indicators.If wide range is unavailable, AFW flow may serve as initial indication offlow to the steam generators and narrow range may be used once the level hasstabilized.

Key 17

In order to provide SG level control, a supply of feedwater is required forthe AFW system. The initial supply is the condensate storage tank (CST). Itis normally aligned and no components are required to function for this key.

Key 19

After the CST (key 17) has reached its low level as indicated by low pumpsuction pressure, the suction for the AFW system must be switched to the ERCWsystem. For shutdown from the MCR, AFW pump suction may be transferred bymanually opening the isolation valves corresponding to the operating AFWpump(s). For shutdown from the ACR, transfer will occur automatically. Thepiping for the AFW supply branches off from the discharge headers in the ERCWsystem. Therefore, a flow path in the ERCW system must be provided to thedischarge header which supplies the pump in operation.

Suction for the turbine driven AFW pump may be taken from either the A or B

ERCW discharge header.

NEB - Mar. 28, 1985E54270.03 --B 4 -

Key 34

The normal charging path is aligned during power operation. If the normalflow control valve (key 2), FCV-62-93, is not available to throttle thecharging flow, then one of the inline motor-operated valves must becontrolled to throttle the flow.

Normal charging may be provided to the cold leg of loop 1 or the cold leg ofloop 4. The inline valves which could spuriously !solate the flow are notcovered in the plant technical specifications. Since either path may be inuse, both paths must be shown to be available at any time.

Key 35

If the pressurizer heaters are not operable due to fire damage, the plantmust be taken directly to cold shutdown. This requires that the equipment inkeys 30, 31, 36, and 40 be free of fire damage and immediately available tobring the plant to cold shutdown.

Key 36

As the RCS depressurizes while the plant is brought to cold shutdown, theUHI and SIS cold leg accumulators must be isolated. This requires closure ofthe UHI isolation gag valves and the accumulator isolation valves. If theaccumulators (UHI and SIS cold leg) cannot be isolated, they must bedepressurized by venting the cover gas.

Key 37

This key contains the HVAC equipment required to achieve and maintain hotstandby'. Air conditioning is required for the MCR. The ventilation systemsare required for the DG building, and the turbine-driven AFW pump room.All other areas which contain safe shutdown equipment were evaluated and itwas determined that acceptable temperatures will be maintained for 72 hoursif all HVAC is lost. One exception is the 480V transformer room lA. Ifcooling is lost in this room, and the room temperature exceeds lO40F, theoperator must begin removing loads from the 480V auxiliary building commonboard transformer and turn off room lighting to maintain room temperautrebelow 1220F.

Key 40

When taking the plant from hot standby to cold shutdown, the only additionalHVAC function required is RHR pump room cooling. This is supplied by theRHR pump room cooler with cooling water from the ERCW system. If coolerfails due to fire damage, portable fans may be installed to provide roomcooling.

E54270.03 -B7 - NEB - Mar. 289 1985

APPENDIX D

A fire may cause a spurious safety injection (SI) signal. If this occurs, thefollowing components required for safe shutdown will be affected. Othercomponents which receive an SI signal that are not required for safe shutdownare not listed since their position will not affect safe shutdown of the plant.The key numbers refer to the key in which the component is required on the safeshutdown-logic diagram (SLD) (Figure 1).

Component

FCV-1-51

LCV-3-148

LCV-3-156

LCV-3-164

LCV-3-171

LCV-3-172

LCV-3-173

LCV-3-174

LCV-3-175

FCV-63-41

FCV-63-*42

FCV-63-.25FCV-63-*26FCV-63--39FCV-63--40

Key No. Response

14&15

12

12

12

12

16

16

16

16

6

6

6666

Open

Auto level control

Auto level control

Auto level control

Auto level control

Auto level control

Auto level control

Auto level control

Auto level control

Close

Close

OpenOpenOpenOpen

Justification

If the turbine driven AFW pump isin use, the valve is in the desiredposition. If the motor drivenpumps are running, and the valvespuriously opens and starts theturbine driven pump, the excessfeedwater supplied will becompensated for by the steamgenerator level control valves.

Note 1

Note 1

Note 1

Note 1

Note 1

Note 1

Note 1

Note 1

Note 1, Note 2

Note 1, Note 2

A spurious SI signal will open theECCS charging path. Manual controlof one of these valves will beavailable to throttle chargingflow. On unit 1, FCV-63-39 and -40are normally open with powerremoved.

Note 1: This is the desired position for safe shutdown.

Note 2: On unit 1, the valves are normally closed with power removed.

E54348.04I


FIRE PROTECTIONANALYSIS OF TYPES I AND III ASSOCIATED CIRCUITS OF CONCERN

-1-

Introduction

lOCFR50, Appendix R, hereafter referred to as Appendix R, requires thatnuclear power plants have the capability of reaching hot-shutdown during apostulated fire occuring at any location in the plant. Capability to reachcold-shutdown within 72 hours after the fire is also required; however,repairs within the capability of the onsite maintenance staff arepermitted. Appendix R requires that at least one safe-shutdown path befree from fire damage and that certain spurious actuations be prevented.One possible source of damage to a shutdown path is from fire-inducedfaults on nonshutdown circuits (circuits not required for safe-shutdown,hereafter referred to as non-required circuits) causing unacceptableinteractions with shutdown circuits (circuits required for safe-shutdown,hereafter referred to as required circuits) due to some physical orelectrical commonality; Appendix R defines such nonrequired circuits(whether safety related or not) as Associated Circuits of Concern.

In accordance with Appendix R, there are three types of Associated Circuitsof Concern:

Type I - Circuits that share a common power source with a requiredcircuit where the power source is not electrically protectedfrom the nonrequired circuit by coordinated circuit breakers,fuses, or similar devices.

Type II - Circuits that share a connection with circuits of equipmentwhose spurious operation could adversely affect the shutdowncapability.

Type III - Circuits that share a common enclosure (e.g., cable tray,conduit, panel, or junction box) with a shutdown circuit and,

a. are not electrically protected by circuit breakers fuses,or similar devices, or

b. could allow propagation of fire into the common enclosure.

The scope of this discussion is limited to Type I and Type III circuits. AType I or Type III circuit is not an Associated Circuit of Concern if ithas adequate electrical protection.

Typ I - Common Power Supply Analysis

A circuit, whether safety related or not, is classified as a potentialAssociated Circuit of Concern if it is supplied by a power source that alsosupplies an Appendix R "Required Circuit."

All required circuits were identified from the Appendix R Shutdown LogicDiagrams. From these circuits, all required power supplies were identified.

015037.01

The common power supply evaluation examined selective coordination ofelectrical protective devices for the required power sources anddistribution panels. Selective coordination ensures that the power sourcewill be available for the required circuits and cables that are notinvolved in the fire. Even if the non-required circuits were faulted bythe fire, their individual circuit breakers or fuses would clear the faultsbefore the main board protective device or upstream feeder protection wouldopen rendering the required power source unavailable.

The highest fault current will occur when the non-required circuits arefaulted at the point closest to the distribution panel where their cablescould be involved in a postulated fire without also involving the requiredcables or the distribution panel itself. Based on this criteria thefollowing steps were performed for each required power supply:

1. The maximum fault current for each nonrequired circuit was calculated.

2. Selective coordination was examined between the faulted circuit'sprotective device and all upstream feeder breakers and fuses. This wasdone by plotting the time/current characteristic curves for theprotective devices and determining if the individual branch circuitbreaker would operate before all upstream devices for the maximum faultcurrent.

For each power system evaluated the acceptance criteria required theelectrical protection to be selectively coordinated such that fireinduced branch circuit faults will be cleared by at least one of thebranch circuit's protective devices without opening the main boardprotective device or upstream feeder protection.

TvpM III - Common Enclosure Analysis

A circuit whether safety-related or not, is classified as an AssociatedCircuit of Concern if it shares a common enclosure (e.g., cable tray,conduit, panel, or junction box) with an Appendix R "Required Circuit,"and,

a. is not adequately protected by circuit breakers, fuses, or similardevices, or

b. could allow propagation of the fire into the common enclosure.

Watts Bar Nuclear Plant has five different voltage level groupings ofraceway (conduit and cable tray) systems, namely: 6900-volt, 480-volt,control, medium-level signal, and low-level signal cables. The 6900-volt,480-volt, and control groupings are divided into divisional and non-divisional raceway systems. The 6900-volt raceways contain only 6900-voltcables and are located at the top position of vertically stacked trays.The 480-volt raceways have 480-volt power cables, lighting cabinet feeders,and instrumentation and control power cables carrying 30 amperes or more.

Control level raceways contain ac and/or dc control cables that carry lessthan 30 amperes and communication cables, such as for telephone circuits.

015037.01

Medium-level signal and low-level signal trays contain only non-divisionalcabLes and are located at or near the lowest level of stacked trays.Divisional medium-level signal cables are routed in conduit. Medium-levelsignal trays carry the following type cables: signal cables of digitalinput to and outputs from the computer other than thermocouples; instrumenttransmitters, recorders, and indicators; eccentricity and rotor detector,RTD's, tackometers, and shielded annunciator cables used with solid-stateequipment. Signal cables for thermocouples,, strain gauges, vibrationdetesctors, and thermal converters are nondivisional and are run in low-level signal raceways. These type cables are for very low power circuitsused to convey information. Thus, energy produced by electrical faults inthe cables routed in medium-level signal and low-level signal trays isconsidered insignificant and is considered no challenge to shutdowncapability. Since instrumentation circuits required for shutdown will meetsect:ion III.G.2. of Appendix R, there are no associated circuits of concernin these groupings.

For the remaining voltage-level groupings of raceway systems, a Type IIIcommon enclosure evaluation was performed using the following assumptions.

1. Circuits routed entirely in conduit do not have to be analyzed forcommon enclosure associated circuits unless they share a conduit with arequired circuit.

2. The smallest conductor used in control circuits which is adequatelyprotected by a 10-ampere circuit breaker or fuse is 16 AWG. Therefore,cables in 10-ampere circuits are not listed as potential associatedcircuits of concern. The exceptions to this assumption were identifiedby obtaining a computer generated list and evaluating all controlvoltage level cables less than 16 AWG.

3. The Appendix R analysis was performed with the latest revision of the"as designed" drawings.

4. All circuits that require electrical power to function and that arerequired to achieve the Appendix R "hot shutdown condition" are locatedin Category I structures.

5. Current transformer (CT) secondary circuit protection is not requiredbecause of inherent current limiting due to saturation to limits withintheir maximum withstand capability of 20 times rated secondary current.All CT secondary circuits are designed for 5 amps or less at ratedprimary current and are cabled using a minimum # 10 AWG. Higher CTsecondary current is possible only during primary circuit faults whichwill clear in approximately 3 to 5 cycles. Therefore, CT secondarycircuits do not pose a fire initiation hazard and are not listed.

6. No analysis is required for circuits contained in a singular firearea.

015037 .01

! , I

7. A common enclosure analysis was not performed on the 120V ac PermanentHydrogen Mitigation System (PHMS) Power Distribution Panels 1A, iB, 2A,and 2B, since the cables powered from this system are routed entirelyin conduit.

8. The cabling and protective devices for the non-Class 1E circuits routedwithin Category I structures were evaluated to resolve licensingcondition 16 of the Safety Evaluation Report (SER). In that analysis,it was shown that the protective device for each non-Class 1E circuitwould clear any credible fault before the cable reached itsauto-ignition temperature and started a fire which could damageClass 1E cabling or equipment. The cabling and protective devicecomparison of each circuit is attached to a memorandum fromJ. C. Standifer to F. W. Chandler dated November 17, 1982(SWP 821118 030). Since this acceptance criteria is appropriate forthe Appendix R common enclosure analysis, no further analysis wasperformed on these cables.

The common enclosure evaluation was performed on each Class 1E power systemwhole cables were routed in the 6900-volt, 480-volt, and control raceways,inside Category I structures. The following steps were performed incompiling the data for evaluation on each of these power systems.

1. For each protective device used in the power systems under review, adata sheet was prepared.

2. Cables connected to this protective device and routed in cable tray(s)inside Category I structures were identified and tabulated on the datasheets until the "end" load device was found. This tabulation includedcables which met the following criteria:

a. the protective device is greater than 10 amperes, or

b. the protective device is in one fire zone and its cabling extendsinto another fire zone, or

c. the protective device is in a non-Category I structure and itscabling extends into a Category I structure which contains requiredcircuits.

3. For those circuits, where a 10-ampere or less protective device wasidentified, only the first cable downstream of this device was listed.

For the cables powered from the Control Power Systems (i.e., 120VAC and125:VDC power systems) the following acceptance criteria was used.Control power cables and their protective devices which met both of thefollowing criteria were adequately protected:

1. The continuous current rating of the cable was greater than the triprating of the protective device. If the cable's continuous currentrating was between two standard protective device ratings, the higherrated device provides adequate protection (reference National ElectricCode, 1984 edition, articles 240-3 and 240-6).

015037.01

? v

2. The protective device must have cleared or limited the fault currentsuch that the conductor temperature was not elevated to the auto-ignition temperature of the cable insulation given in Table A. Forcopper conductors, the following equation (reference ICEA P-32-382) wasused to make this determination:

( I ) 2t = 0.0297 log T? + 234 Equation A(A) T1 + 234

where,

I = maximum short circuit current (assuming a fault at the pointclosest to the distribution panel where a cable could be involvedin the fire without also involving the distribution panel)

A = conductor area in circular mils

t = duration of fault in seconds

Tj = maximum operating temperature in OC

T2 = auto-ignition temperature of insulation in OC

TABLE A

Cable Insulation - Auto-Ignition Temperatures

Insulation Material Temperature, 0C

Polyethylene (PE) 455Cross-Linked Polyethylene (XLPE) 530Ethylene-Propylene Rubber (EPR) 530Silicon Rubber 570Teflon/Tefzel 530

For the cables powered from the Auxiliary Power Systems (i.e., 6900V ac and480V ac power systems) the following criteria was used:

Plotting the cable's auto ignition damage curve (see figure A below) andthe electrical protective device(s) operating characteristics, the circuitwas adequately protected if at least one of the circuit protective deviceslay to the left and below the cable damage curve for all credible faultcurrents. This ensured that the cable insulation would not reach its auto-ignition temperature.

The! currents required to elevate the cable insulation to auto-ignitiontemperature was developed by using Equation A above, with one variation.The current, I, was defined as the current relative to time forauto-ignition of the cable insulation. Assuming no heat transfer occurredand by selecting sufficient time intervals beginning at t = .01 second,currents were calculated and used to develop a cable auto-ignition curve.

015037.01

l

The curve was extended to the point where it intersected a verticalline defined to be the maximum continuous current, 1TR, that the conductorcould carry without cable insulation damage. See Figure A below.

- a

a

' I

0

8 VI-u

.60i, "

I I0 -4

-, .4

I. ,

.01

A

,TR(Equation B)

I (Equation A)

Figure A - Plot of Current Versus Time to Auto-Ignition* ofthe Cable Insulation

*AppLicable only to the portion of curve between .01 second and the timecorresponding to point A.

The maximum continuous current, ITR, that the conductor could carry withoutcable insulation damage was determined as follows:

TR - TAF.L. Temperature Rise

X F.L. Equation B

ITR = The maximum continuous current that the conductor can carry withoutdamaging the cable insulation in amps

TR = Cable insulation damage temperature in OC (see Table B)

TA = Ambient temperature in OC

F.L. Temperature Rise = The conductor temperature at rated current inOC - TA

F.L. - Continuous current rating of the cable in amps

015037.01

ITR a=

where,

TABLE B

Cable Insulation - Damage Temperatures

Insulation Material Temperature 0C

Polyethylene (PE) 125Cross-Linked Polyethylene (XLPE) 250Ethylene-Propylene Rubber (EPR) 250Silicon Rubber 300Teflon 270Tefzel 250

Conclusion

The results of these analyses indicate that the auxiliary power sources andcontrol power sources required for operation of the required equipment areelectrically protected from the associated circuits of concern byselectively coordinated breakers and/or fuses, except those circuits listedin Attachment 1. For these circuits, selective coordination was notassured for the fault current levels calculated; therefore, these circuitsare Type I associated circuits and corrective action is required. Thecorrective action for each of these cables is provided in Attachment 1.

In addition, the results indicate that the associated circuits of concernpowered by the auxiliary and control power systems which may share a commonenclosure (e.g., cable tray, conduit, panel, or junction box) with arequired circuit are properly protected by circuit breakers and/or fuses,except those circuits listed in Attachment 2. For these circuits, adequateelectrical protection is not provided, therefore, these circuits are TypeIII associated circuits and corrective action is required. The correctiveaction for each of these cables is provided in Attachment 2.

015037.01

ATTACHMENT 6-1TYPE I ASSOCIATED CIRCUITS OF CONCERN

-1-

Sheet 1 of 20

WATTS BAR NUCLEAR PLANTAPPENDIX R CABLE ANALYSIS

TYPE I COMMON POWER SUPPLY ASSOCIATED CIRCUITS

CONTROL POWER X

BOARD 125V VITAL BATTERY BOARD I OR POWER

PREPARED BY:jr244/7 ,,ATE: 2-7-8S

CHECKED BY:itjPye <DATE: 9,2 & 5C

COMPT. ORPANEL NO. CIRCUIT ENGLISH NAME CABLE CORRECTIVE ACTION

3 UNIT I AUXILIARY RELAY RACK 1-R-54 1B40A RELOCATE CABLE 1B36A FROM BKR. NO.315 TO EITHER BKR. NO. 309 OR BKR.NO. 319.

NOTE: IF THE ABOVE CABLE LISTED IN THE CORRECTIVEACTION COLUMN IS RELOCATED TO BKR. NO. 309,THE EXISTING BREAKER MUST BE REPLACED WITH

A 15A. BREAKER.DE07;APPR.WB

- . - . .=- -------



Sheet 2 of 20

BOARD 125V VITAL BATTERY BOARD II

COMPT. ORPANEL NO.

CONTROL POWER XOR POWER

CIRCUIT ENGLISH NAMECAnI �

PREPARED BY:.j 34a.,DATE:;2 -2--?5

CHECKED BY:/4',d1 4DATE: 2 jA

CORRECTIVE ACTIONCORRECTIVE ACTION

3 UNIT 1 AUXILIARY RELAY RACK 1-R-55 1B41B RELOCATE CABLE 1B37B FROM BKR. NO.315 TO EITHER BKR. NO. 309 OR BKR.NO. 319.

NOTE: IF THE ABOVE CABLE LISTED IN THE CORRECTIVEACTION COLUMN IS RELOCATED TO BKR. NO. 309,THE EXISTING BREAKER MUST BE REPLACED WITHA 15A. BREAKER.DE07;APPR.WB

r A UT

Sheet 3 of 20WATTS BAR NUCLEAR PLANTAPPENDIX R CABLE ANALYSIS


CONTROL POWER XBOARD 125V VITAL BATTERY BOARD III OR POWER

PREPARED BYLA le .ATE: ;7-35

CHECKED BY: 4 .4 Pyn1DATE: 7AERM16_


3 UNIT 2 AUXILIARY RELAY RACK 2-R-54 2B40A RELOCATE CABLE 2B36A FROM BKR. NO.315 TO EITHER BKR. NO. 309 OR BKR.NO. 319.


-

Sheet 4 of 20WATTS BAR NUCLEAR PLANT

APPENDIX R CABLE ANALYSISTYPE I COMMON POWER SUPPLY ASSOCIATED CIRCUITS

BOARD 125V VITAL BATTERY BOARD IVCONTROL POWER XOR POWER

PREPARED BY: N39 DATE:e2-7^8S

CHECKED BYI2dl DATE: 9f i&Si


3 UNIT 2 AUXILIARY RELAY RACK 2-R-55 2B41B RELOCATE CABLE 2B37B FROM BKR. NO.315 TO EITHER BKR. NO. 309 OR BKR.NO. 319.


-



BOARD 480CONTROL POWER

VOLT SHUTDOWN BOARD lAl-A OR POWER X

PREPARED BY: DATE: 3-Tz85

CHECKED BY: - m DATE:J4'685


NORMAL FDR BKR, CONTROL AND AUXILIARY BUILDINGVENT BOARD 1A1-A

ALTERNATE FDR BKR, CONTROL AND AUXILIARYBUILDING VENT BOARD 1A2-A

N/A

N/A

RESET BREAKER

RESET BREAKER

DEO7 ;APPR.WB

10B

10D



CONTROL POWEROR POWER XBOARD 480 VOLT SHUTDOWN BOARD 1B1-B

COMPT. ORDAMNFT Un CARLF.

Sheet 6 of 20 .

PREPARED BY: 7%re> DATE :5-Z?-*5

CHECKED BY: - DATE: -28-F5

CORRECTIVE ACTION

NORMAL FDR BKR, CONTROL AND AUXILIARY BUILDINGVENT BOARD IB1-B

ALTERNATE FDR BKR, CONTROL AND AUXILIARYBUILDING VENT BOARD 1B2-B

N/A

N/A

RESET BREAKER

RESET BREAKER

DE07;APPR.WB

fl WN . ------ *U

10B

9A

rT1rTITT7 VN1CT.TRU NAMR



BOARD 480 VOLT SHUTDOWN BOARD 1A2-A -_-_-_-_-_-_-

COMPT. ORT 1t-1 M1n

CONTROL POWEROR POWER X

CART.-

lwSheet 7 of 20 ,

PREPARED BY: _ DATE: 3-2_-R

CHECKED BY: _ +/A TDATE:..i 6-9

CORRECTIVE ACTION

ALT FDR BKR, CONTROL AND AUXILIARY BUILDINGVENT BOARD lAl-A

ALT FDR, REACTOR VENT BD 1A-A

N/A

N/A

RESET BREAKER

RESET BREAKER

DE07;APPR.WB

9 B

1OA

OTDPTITT FTlrT TQU NAMF

-1- 1- -�-ra-L -. . Iw ..... ... 11-1-




COMPT. ORPANEL NO. CIRCUIT ENGLISH NAME CABLE

Sheet 8 of 20

PREPARED BY: JP)w- DATE: 3-z_-_ -

CHECKED BY: DATE - '5

CORRECTIVE ACTION

ALT FDR BKR, CONTROL AND AUXILIARY BUILDING N/AVENT BOARD 1BI-B

RESET BREAKER

DE07;APPR.WB

9B

Sheet 9 of 20'WATTS BAR NUCLEAR PLANT


BOARD 480

COMPT. ORPANEL NO.

CONTROL POWEROR POWER XVOLT SHUTDOWN BOARD 2A1-A

CTRCTTTT ENCT.TRH NAME. rA1RLT.R

PREPARED BY:.7•.±W DATE: -Z

CHECKED BY:,ir. DATE-3-2,'S

CORRECTIVE ACTION

NORMAL FDR BKR, CONTROL AND AUXILIARY BUILDINGVENT BOARD 2A1-A

ALT FDR BKR, CONTROL AND AUXILIARY BUILDINGVENT BOARD 2A2-A

N/A

N/A

RESET BREAKER

RESET BREAKER

DE07;APPR.WB

10B

10D

Sheet 10 of 20 'WATTS BAR NUCLEAR PLANT


CONTROL POWER'OR POWER XBOARD 480 VOLT SHUTDOWN BOARD 2B1-B


PREPARED BY: re'A.e DATE: -z-S

CHECKED BY:, / DATE:_-__-_

CORRECTIVE ACTION

NORMAL FDR BKR, CONTROL AND AUXILIARY BUILDINGVENT BOARD 2B1-B

ALT FDR BKR, CONTROL AND AUXILIARY BUILDINGVENT BOARD 2B2-B

-N/A

N/A

RESET BREAKER

RESET BREAKER

DE07;APPR.WB

10B

9A



CONTROL POWEROR POWER XBOARD 480 VOLT SHUTDOWN BOARD 2A2-A


wSheet 11 of 20 -

PREPARED BY: f DATE:3-2---5-

CHECKED BY: go L , DATE:-'iF7"s

CORRECTIVE ACTION

ALT FDR BKR, CONTROL AND AUXILIARY VENTBOARD 2A1-A

ALT FDR, REACTOR VENT BD 2A-A

N/A

N/A

RESET BREAKER

RESET BREAKER

DE07;APPR.WB

9B

10A




PREPARED BY: r DATE:3-Z-.5-

CHECKED BY: A;1ATE:Y 2 -_


ALT FDR BKR, CONTROL AND AUXILIARY BUILDINGVENT BOARD 2B1-B

ALT FDR BKR, REACTOR VENT BOARD 2B-B

N/A

N/A

RESET BREAKER

RESET BREAKER

DE07;APPR.WB

9B

9A

ATTACHMENT 6-2TYPE III ASSOCIATED CIRCUITS OF CONCERN

-1-


TYPE III COMMON ENCLOSURE ASSOCIATED CIRCUITS

CONTROL POWEROR POWER XBOARD 480V C&A VENT BDS lAl-A

COMPT. ORCIRCUIT ENGLISH NAME

SHUTDOWN BOARD ROOM PRESS FAN A-A

TRAVELING SCREEN 1A-A

CABLE

/PL33o4/A

/iP 388o4

Sheet 13 of 20 -

PREPARED BY $k DATE Y?-ZA

CHECKED BY4.<A,.im....JDA3 E: J-2-f-F

CORRECTIVE ACTION

CHANGE OL HTR

RESET CIRCUIT BKR

DE07;APPR.WB

PANEL NO.

6A

6C



Sheet 14 of 20 -

BOARD 480V C&A VENT BDS lBl-BCONTROL POWEROR POWER X

PREPARED BY/y DATE :-.Z?-d'-

CHECKED BY: -•:k•-e5-r

COMPT. ORPANEL NO.

3C

liB

5E

CIRCUIT ENGLISH NAME

CNTMT SPRAY PUMP lB-B RM COOLER FAN

480V BD RM 1/C AHU 1B-B

CCS & AUX FEEDWATER PUMPS SPACE COOLER FAN B-B

CABLE

/PL 32 /3

CORRECTIVE ACTION

CHANGE OL HTR

CHANGE CABLE SIZE

CHANGE OL HTR

DE07;APPR.WB

Sheet 15 of 20 ,



BOARD 480V C&A VENT BDS 2A1-A

COMPT. ORPANEL NO. CIRCUW

CONTROL POWER -

OR POWER X

'IT ENGT.TH NAME CARLE

PREPARED BY: X + DATE J-723-Y

CHECKED BY: : 23-?

CORRECTIVE ACTION

AUX CONTROL AIR COMPRESSOR A-A

CNTMT SPRAY PUMP 2A-A RM COOLER FAN

ERCW TRAVELING SCREEN 2A-A

480V XFMR RM 2A EXHAUST FAN 2A1-A

0ZL 3795A

2&30 S5/?

2p438w,'

,?a 28A 6 A

CHANGE OL HTR

CHANGE OL HTR

RESET CIRCUIT BKR

CHANGE OL HTR

DE07;APPR.WB

2A

3C

6C

9D

--- -L - Ussv=



BOARD 480V C&A VENT BDS 2B1-B

COMPT. ORPANEL NO. CIRCU

CONTROL POWER -OR POWER X

IT ENGLISH NAME

AUX CONTROL AIR COMPRESSOR B-B

CNTMT SPRAY PUMP 2B-B RM COOLER FAN

AUX FEEDWATER AND BORIC ACID TRAS PUMPS COOLER FAN

480V BD RM 2B A/C AIR HANDLING UNIT 2B-B

CABLE

2P4 379KB

ZPL 366/Y

ZPL 31 olI

ZAPL /0 705

Sheet 16 of 20-

PREPARED BY: le DATE: -7 -23 -

CHECKED BY:` Az-pj-

CORRECTIVE ACTION

CHANGE OL HTR

CHANGE OL HTR

RESET CIRCUIT BKR

CHANGE CABLE SIZE

DE07;APPR.WB

2A

3C

5E

lB



Sheet 17 of 20 '

BOARD 480V REACTOR MOV BDS lAl-A

COMPT. ORPANEL NO. C.TRCU.ITT I


PREPARED BY, e% DATE: 3-,U-.s5

CHECKED BY .L E: i~-rF

CORRECTIVE ACTION

COMPONENT COOLING SYSTEM BOOSTER PUMP 1A-A

RRR PUMP 1A-A INLET FLOW CONT VLV

REFUELING WATER PURIFICATIPN PUMP A-A

/PL 63ZD

IP4 63 S-A

CHANGE OL HTR

CHANGE OL HTR

CHANGE OL HTR

DE07;APPR.WB

2C

14B

18A

----- on IADLZNr-.T.Tn RUAMP r A OT r



Sheet 18 of 20 -

BOARD 480V REACTOR MOV BDS lBl-B -ORO L POWER CHECKED


2C COMPONENT COOLING SYSTEM BOOSTER PUMP 1B-B IP&131B CHANGE OL HTR15A RHR PUMP lB-B INLET FLOW FCV 1/l9005 CHANGE OL HTR

18A REFUELING WATER PURIFICATIPN PUMP B l?16380Y CHANGE OL HTR

DE07;APPR.WB

PREPARED B :DATE: 3 -23-0.,

�y-

40WATTS BAR NUCLEAR PLANT

APPENDIX R CABLE ANALYSISTYPE III COMMON ENCLOSURE ASSOCIATED CIRCUITS

BOARD 480V REACTOR MOV BDS 2A1-ACONTROL POWEROR POWER X

Sheet 19 of 20 .,

PREPARED BY 5g; :3A-T3-E'

CHECKED BY Jr-e-r,

COMPT. ORPANEL NO.

2C

14B

CIRCUIT ENGLISH NAME

COMPONENT COOLING SYSTEM BOOSTER PUMP 2A-A

RHR PUMP 2A-A INLET FCV

2 Pe 6/20A

Zvl92e9A

CHANGE OL HTR

CHANGE OL HTR

DE07;APPR.WB

%jLE COUURRECTIVE ACTIONPAnY r



Sheet 20 of 20 '-

BOARD 480V REACTOR MOV BDS 2B1-B

COMPT. ORPANF.T. NO.


- "% fU1jlL.JLo "imr1.r, UAB3LkrTDCTTTT VXMrTTOU ATMAIA

PREPARED BY: X :DATE;7-;',a-

CHECKED BY: .l-/s- B E: _____

CORRECTIVE ACTION

RHR PUMP 2B-B INLET FCV Z Y/ 900ee CHANGE OL HTR

DE07;APPR.WB

15A

. A.

ENCLOSURE 2Tcold INDICATIONS IN AUXILIARY CONTROL ROOM

As discussed in TVA's June 17, 1983 and September 6, 1984 letters toNRC, TVA has provided adequate instrumentation in the auxiliarycontrol room (ACR) to safely shutdown and cooldown the plant duringconditions of main control room inhabitability. The NRC staff hassome concerns about the use of the steam generator secondary sidepressure being used to obtain Tsat, and the subsequent use ofTsat and reactor coolant system hot leg temperature to verifyadequate natural circulation. These concerns were discussed withNRC during a March 7, 1985 meeting in Bethesda. As a result of thatmeeting, TVA agreed to provide NRC a schedule for addressing indetail the staff's concerns. Following is a list of those areas tobe addressed.

1. Discuss operator training on Tsat and any impact of operatorsusing Tsat in the ACR when they normally use Tcold in theMCR.

2. Discuss benefits that steam generator Psat (i.e., Tsat) hasthat Tcold does not provide.

3. Discuss detailed cost estimate of providing Tcold in ACR.

4. Review test data from SQN natural circulation tests.

5. Review stratification in the steam generator at low-steaminglevels.

6. Based on the above data, review/develop detailed basis foradequacy of Tsat vs. Tcold in the auxiliary control room.

7. Review up coming Diablo Canyon natural circulation test data.

Detailed discussions on items one through six will be provided toNRC in a timeframe consistent with staff review before issuance ofthe full power license (approximately 30 days before expected entryinto mode 1). Item 7 will be provided 120 days following theconclusion of the Diablo Canyon natural circulation test.

ENCLOSURE 3

RUSKIN FIRE DAMPERS

This statement is to document the concern of NRC with the TVAproposed for administrative control of fans and air handling unitssupplying or removing air from areas where 76 dampers may not closedue to normal air flow.

The proposal was as follows:

In the areas affected by the 76 dampers, if two or more alarmsfrom thermal and/or smoke detector zones occur and/or thedeluge valves open and the fire brigade is dispatched to theareas, the fans or the air handling units supplying or removingair from the affected areas will be stopped.

The appropriate plant procedures and/or instructions will be revisedor prepared by unit 1 fuel load to implement the above proposal.

Documents

Forwards responses to questions raised during 850321