ML17207A508

Advises of NRC Requirements for Auxiliary Feedwater Sys. Generic & plant-specific Requirements Encl

ML17207A508
Person / Time
Site:	Saint Lucie
Issue date:	10/17/1979
From:	Eisenhut D Office of Nuclear Reactor Regulation
To:	Robert E. Uhrig FLORIDA POWER & LIGHT CO.
References
NUDOCS 7910260288
Download: ML17207A508 (44)

Text

~EPTEhlBER 3 g tgyg Docket, No. 50-335 Mr. Robert E. Uhrig, Vice-President Advanced Systems and Technology Florida Power and Light Company P. 0.

Box 629100 Miami, Fl orida 33152

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Dear Mr. Uhrig:

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SUBJECT:

NRC RE(UIREMENTS FOR AUXILIARYFEEOWATER SYSTEMS AT ST. LUCIE UNIT 1

The purpose of this letter is to advise you of our requirements for the auxiliary feedwater systems at the subject facility.

These requirements were identified during the course of the NRR Bulletins and Orders Task Force review of operating reactors in light of the accident at Three Mile Island, Unit 2.

Enclosure 1 to this letter identifies each of the requirements applicable to the subject facility.

These requirements are of two types,

( 1) generic requirements applicable to most Combustion Engineering-designed operating

plants, and (2) plant-specific requirements applicable only to.the subject

<<tacility.

Enclosure,2 contains a generic request for additional information regarding auxiliary feedw'ater system flow requirements.

The designs.and procedures of the subject facility should be evaluated against the applicable requirements specified in Enclosure 1 to determine the degree to which the facility currently conforms to these requirements.

The results of thi s evaluation and an associated schedule and comitment for implementation of required changes or actions should be provided for NRC staff review within thirty days of receipt of this letter.

Also, this schedule should indicate your date for submittal of information such as design

changes, procedure changes or Technical Specificati'on changes to be provided for staff review.

You may also provide your response to the items in Enclosure 2 at that time.

1 In addition to the requirements identified in this letter, other requirements which may be applicable to the subject facility are expected to be generated by the Bulletins and Orders Task Force.

Such requirements are those resulting from our review of the loss-of-feedwater event and the small break loss-of-coolant accident as described in the Combustion Engineering report CEH-114-P (Amendment 1-P )

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. -guidelines ag)'procedures foi op'erators,'nd operator,'training.

- Wevplan to identify, in separateIcorrespondence; the. requirements resulting from the additional items from the Bulletins.hnd Order's

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~ Sincerely, Original signed by Qarrell G. Eisenhut" v

Darrell G.'isenhut, Acting Di'rector Division of Operating Reactors'ffice of Nuclear Reactor Regulation Encl osures:

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Florida Power 8 Light Company SEPTEhlBER 2 1 i979 CC:

Robert Lowenstein, Esquire Lowenstein,

Newman, Reis 5 Axelrad 1025 Connecticut Avenue,'.W.

Mashington 0.

C.

20036 Norman A. Coll, Esquire HcCarthy, Steel, Hector

& Davis 14th Floor, First National Bank Building Miami, Florida 33131 Nr. Jack Shreve Office of the Public Counsel Room 4, Holland Bldg.

Tallahassee, Florida 32304 Indian River Junior College Library 3209 Virginia Avenue Fort Pierce, Florida 33450

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Docket No. 50-335 UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 October

,17

, 1979 Mr. Robert E. Uhrig, Vice-President Advanced Systems and Technology Florida.Power and Light Company P. 0.

Box 529'100 Miami, Fl o'rida 33152

'ear Mr. Uhrig:

SUBJECT:

NRC RE(UIREMENTS FOR AUXILIARYFEEDMATER SYSTEMS AT ST.

LUCIE UNIT 1

The purpose of this letter is to advise you of our requirements for the auxiliary feedwater systems at the subject facility.

These requirements were identified during the course of the NRR Bulletins and Orders Task Force review of operating reactors in light of the accident at'hree Mile Island, Unit 2.

P Enclosure 1 to this letter identifies each of the requirements applicable to the subject facility.

These requirements are of two types, (1) generic requirements applicable to most Combustion Engineering-designed operating

'lants, and (2) plant-specific requirements applicable only to the subject facility.

Enclosure 2 contains a generic request for additional information regarding auxiliary feedwater system flo'w requirements.

The designs and procedures of the subject facility should be evaluated against the applicable requirements specified in Enclosure 1 to determine the degree to which the facility'currently conforms to these requirements.

The results of this evaluation and an associated schedule and comIitment for implementation of required changes or actions should be pr'ovided for NRC staff review, within thirty days of recei pt of thi s letter.

Also, this schedule should indicate your date for submittal of information such as design

changes, procedure changes'r Technical Specification changes to be provided for staff review.

You may also provide your response to the items in Enclosure 2 at that time.

In addition to the requirements identified in this letter, other requirements which may be applicable to th'e subject facility are expected to be generated by the Bulletins and Orders Task Force. 'uch requirements are those resulting from our review of the loss-of-feedwater, event and the small break loss-of-coolant accident as described i n the Combustion Engineering report CEN-114-P (Amendment 1-P )

~ Mr. Robert E. Uhrig October 17, 1979

entitled, "Review, of Small Break Transients in Combustion Engineering Nuclear Steam Supply Systems."

Our specific concerns include systems reliability (other than the auxiliary feedwater system),

analyses, guidelines and procedures for operators, and operator training.

We plan to identify, in separate correspondence, the requirements resulting from the additional items from the Bulletins and Orders Task Force review.

incerely,

Enclosures:

As stated Darrell G. Eisenhut, cting irector Division of Operating Reactors Office of Nuclear Reactor Regulation cc:

see next pag'e

Combustion Engineering Owners Group Representatives

'r. G. E. Liebler, Chairman Combustion Engineering Owners Group Florida Power and Light Company P. 0.

Box 013100 Miami, Florida

.33101 Mr. Joseph K. Gasper, Vice Chairman Combustion Engineering Owners Group Omaha Public Power District fourth

'& Jones

Omaha, Nebraska 68108 Mr. John Garrity, Chairman.-

Guidelines Subgr'oup Maine Yankee Atomic Power Company Edi son Dri ve

Augusta, Maine 04336 Mr. Robert G. Harris, Chairman Analysis Subgroup Northeast Utilities Service Co.

,P. 0.

Box 270 Hartford, Connecticut 06101 Mr. David S.

Van de Walle Consumers Power Company 212 West'Michigan Avenue

Jackson, Michigan 49201 Mr. William Szymczak Yankee Atomic Power Company 25 Research Drive Westboro,'assachusetts 01581 Mr. J. T. Enos Arkansas Power 8 Light Company P. 0.

Box 551 Little Rock, Arkansas 72203

1 Combustion Engineering Principal Contact Listing Mr. David Bixel Nuclear Licensing Admiistrator Consumers Power Company 212 West Michigan Avenue

Jackson, Michigan 49201 Mr. William Cavanaugh, III Executive Director of Generation and Construction Arkansas Power 8 Light Company P,. 0.

Box 551 Little'Rock, Arkansas 72203 Mr. A. E. Lundvall, Jr.

Vice-P'resident- - Supply Baltimire Gas 8 Electric Company P.

Box 1475

'8al t imore,. Maryland 21203 Mr. Theodore E. Short

.Assistant General Manager Omaha Public Power District 1623 Harney Street

Omaha, Nebraska 68102 Mr. Robert H. Groce Licensi'ng Engineer Yankee Atomic Electric Company 20 Turnpike Road l'estboro, Massachusetts 01581 Mr.

W. G. Counsil, Vice-President Nuclear Engi'neering 5 Operations Northeast Nuclear Energy Company P.

O.

Box 270 Hartford, Connecticut 06101 Dr. Robert E. Uhrig, Vice-President Advanced Systems 6 Technology

=

=- Florida Power 6 Light Company P. 0.

Box 529100 Miami, Florida 33152

Ff ori da power 6 LigCoopaoy CC:

Robert Lo>>enstein, Esquire Lowenstein,

Newman, Reis 5 Axelrad 1025 Connecticut

Avenue, N.W.

Mashington, 0.

C.

20036 Norman A. Coll., Esquire McCarthy, Steel, Hector 8 Davis 14th Floor, First National Bank Building Miami, Florida 33131 Mr. Jack Shreve Office of the Public Counsel Room 4, Holland Bldg..

Tallahassee, Florida 32304 Indian River Junior College Library 3209 Virginia Avenue Fort Pierce, Florida 33450

0

ENCLOSURE 1 X.j ST.

LUCIE UNIT 1

AUXILIARYFEEDWATER SYSTEM X.7.1 X: 7.1.1 S stem Descri tion Confi uration Overall Desi n

A simplified flow diagram of the St.

Lucie auxiliary feedwater system (AFWS) is shown in Figure 1.

The AFWS consists of one full capacity turbine&riven pump (500 gpm 8 1200 psi) and two half capacity (250 gpm 8 1200 psi) motor-driven pumps.

One turbine pump or both motor driven pumps are required to adequately remove decay heat.

The turbine-driven p'ump supplies feedwater to two steam generators (SG) by means of. two separate lines each with its own motor operated control valve.

Each motor-driven pump normally supplies feedwater to one steam generator.

A cross connection with two remote manual nor-mally closed isolation valves is provided to enable the routing of feed flow of the two motor driven pumps to either steam generator.

The AFWS is manually started from the control room.

The AFW system can supply water to the SG(s)

Assuming 'a single active component failure with loss of offsite or onsite power

. The licensee states that the AFWS is capable of cooling the plant down to the condition where the shutdown cooling system can be used to continue the safe plant shutdown, process.

The primary water supply of the AFWS is maintained in a 250,000 gal.

seismic Category 1 condensate storage tank (CST) connected to the pumps'uction by redundant lines with locked open manual valves.

A minimum of 168,000 gal. is reserved strictly for the AFWS by administrative control.

The reserved water inventory i s sufficient to maintain the plant at hot standby condition for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following a reactor trip, and subsequently cool the plant down to the shutdown cooling system cut-in temperature.

Low water level in the CST will alarm and annunciate in,the main control room.

The AFW pump suctions are connected only to the CST.

Additional water may be supplied either from the SG Blowdown Monitor Storage Tank or the city water tanks. via the CST as shown in Figure 1.

Supplying water from these alternate sources requires considerable operator action and is estimated to take 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> to accomplish.

X.7.1.2 Com onents - Desi n

Classification All components of the AFWS, including the primary water supply, are designed to seismic Category 1 requirements.

X.7.1.3 Power Sources The steam turbine driven pump uses steam from the main steam lines taken upstream of each main steam isolation valve (HSIV) and exhausts to the atmosphere.

The steam is supplied via an AC powered motor operat-ed.valve (MOV) from each steam generator.

These valves are normally closed and fail as-is.

Downstream of these valves there is a single

steam supply header with a DC powered f10V which is normally closed

~,and fails as-is.

The two motor driven pumps are powered from the Division A and B emergency diesel generators respectively in case of a loss of normal AC power.

X.7.1.4 X.7.1.4.1 Instrumentation.and Controls Controls The control of auxiliary feedwater flow and steam generator water level is accomplished from the control room by remote manually operated control valves.

A local control station is provided to facilitate'lant shutdown if the control room is not accessible.

All manually operated valves in the AFWS are locked open.

The motor operated valves will.fail in the "as-is" position.

X.7.1.4. 2 Information Available to 0 erator The important'information available to the operator includes AFW discharge header flow, AFW discharge header pressure, CST level, steam generator

level, steam pressure to steam driven AFW pump, and control valve position indication.

Additional information available is listed in the following instrument list:

Auxiliar Feedwater Parameters Available on RTGB 102.

Vertical

Section, Aux Feedwater Flow, Header 'A'I-09-2A 2.

Aux Feedwater Flow, Header 'B'I-09-28

3.

Aux Feedwater Flow, Header 'C'I-09-2C 4.,

Aux Feedwater Press.

"Header 'A'I-09-8A 5.

Aux Feedwater Press.

Header 'B'I-09-8B 6.

Aux'Feedwater Press.

Header 'C'I-09-8C 7.

Steam Press.

to Aux 'Feedpump 'C'I-08-5 8.

Condensate Storage Tank Level L'IS-12-11 9.

Aux Feed Pump.'1A'mperes 10.

Aux Feed Pump 'B'mperes Auxiliar Feedwater Parameters on RTGB 102-Horizontal Section l.

AFW Pump*~lA disch steam generator (SG) lA MV-09-9 Switch and valve position, lights.

r 2.

AFW pump 1B di sch to SG 18 MV-09 swi tch and valve posi tion lights.

3.

AFW pump 1C disch to SG 1A MV-09 switch and valve position lights.

4.

AFW pump 1C Oisch to SG 1B MV-09-12 switch and valve position lights.

5.

AFW pump lA disch to. SG 1B MV-09 switch and valve position lights.

(crossconnect valve) 6.

AFW 1B disch to SG lA MV-09-14 switch and valve position lights.

(crossconnect valve)

.7..

Start and stop switches for lA, 1B and 1C Aux Feed Pumps and indicator lights.

8.

1C Aux Feed Pump speed controller and speed indicator.

X.7.1.4.3 9'.

1C Aux Feed Pump steam inlet from 1A main steam line, NV-08-.14 indicator lights.

10.

1C Aux Feed Pump steam inlet from 18 main steam line l1V-08-13 indicator lights.

ll.

1C Aux Feed Pump steam inlet t1V-08-3 indicator lights.

Ini.tiatin Si nals for Automatic 0 eration The St.

Lucie AFWS.is a manually started system.

In the event of a loss of main feedwater pumps or offsite power, followed by reactor trip the licensee estimates that the operator has approximately 13 minutes in which to start the AFW pump and open the AFW flow 1

control valves to'the steam generators to prevent the steam generators from boiling dry.

X.7.1.5

~Te et i n Each month the motor operated feed water valves are cycled from closed to full open to closed, after which each pump is started and operated at least 15 minutes.

Specified minimum discharge pressure is verified while the pumps are operating.

No manual valve lineup changes are required for this testing.

Condensate storage tank level is verified at or above min'imum at least once per 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

X. 7.1. 6 Technical S ecifications 1.

The two motor driven AFW pumps and the steam turbine driven,AFW pump are all required to be operable when the reactor 'coolant system is above 325'F, the maximum operating temperature of the shutdown cooling system.

-6" 2.

If any one pQmp is inoperable, it must be returned to operable status within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> or the plant must be placed in hot standby within 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

3.

If two or more pumps are inoperable, the plant must be in hot standby within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and in cold shutdown within 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br /> unless at least one pump is returned to operation and the unit is back under 2 above using the time intervals of the initial discovery; 4.

The CST is required to have minimum volume of 116,000 gallons when the RCS temperature is above 325'F.

If the volume is below minimum it. must be restored within 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> or the plant must be in hot standby within the next 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in cold shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />.

X.7.2 X.7.2.1 Reliabilit Evaluation Results Dominant Failure tlodes The St.

Lucie Unit j. AFMS consists of two subsystems,

i. e, one subsystem of two one-half capacity motor-driven pumps and another subsystem of a single full capacity turbine-driven pump.

Either subsystem, when delivering its pumping capacity to at least one steam

, generator can provide for adequate decay heat removal for the three loss of main feedwater events considered.

The following failure modes were found to dominate the. demand unavailability of the St.

Lucie AFWS:

Loss of feedwater (LOFM) with offsite AC available Failure to manually actuate the St.

Lucie.Unit 1

AFWS, was assessed to be the dominant failure mode and this fault con-tribution to the overall AFWS unavailability is estimated to be approximately 80 percent.

LOFW with onl onsite AC available St.

Lucie Unit 1

uses a swing tie bus ("AB") that furnishes AC power to valves in the steam turbine driven portion of the AFWS.

This bus is interlocked to prevent tie to more than one emer-gency diesel generator (EOG) simultaneously.

The "AB" bus is normally tied to the "A" EOG.

Thus, the limiting EDG failure would be failure of the "A" EOG.

This failure requires human action to transfer bus "AB" -to the available "8" EOG.

The impact of this human action on the overall AFWS was assessed and found not to significantly alter the above results.

Thus, failure to manually actuate AFWS remains the common dominant failure mode identified.

LOFM with onl DC available For this event, the St.

Lucie Unit 1

AFWS design requi res a

plant operator to proceed to the local valve stations for the steam turbine driven train of the AFWS and open four AC motor

operated valves (2 steam and 2 water) that are normally closed.

The licensee assessment-of accessibility and t'e opening times indicate that this operation could be successfully accomplished by two men in about 5 minutes and one man in about 10 minutes.

Human failure to open these valves has been ass'essed as the dominant fault contributor (~60K) for this event.

X. 7. 2. 2.

Princi al De endencies The principal dependencies identified were those associated with human actions required to 'actuate the St.

Lucie Unit 1

AFWS for the above three events.

X.7.3 Recommendations for this Plant The short-term recommendations identified in this section represent actions to improve AFW system reliability that should be implemented by January 1, 1980, or as soon thereafter as is practicable.

In,

general, they involve upgrading of Technical Specifications or establishing procedures to avoid or mitigate potential system or operator failures.

The long-term recommendations identified in this section involve system design evaluations and/or modifications to improve AFW system reliability and represent actions that should be implemented by January 1, 1981, 'or as soon thereafter's is practicable.

X.7.3.1 Short-Term Recommendations 1.

Recommendation GS Emergency procedures for transferring to alternate sources of AFW supply should be available to the plant operators. 'hese procedures should include criteria to inform the operator

when, and in what order,.the transfer to alternate water sources should take place.

The following cases should be covered. by the procedures:

The case in which the primary water supply is not initially available.

The procedures for this case should include any operator actions required to protect the AFW system pumps against self-damage before water flow is initiated; and, The case in which the primary water supply is being depleted.

The procedure for this case should provide for transfer to the alternate water sources prior to draining of 'the primary water supply.

2.

Recommendation GS The plant should be capable of providing the required AFW flow for at least two hours from one AFW pump train independent of any alternating current power source.

If manual AFW system initiation or flow control is required following a complete loss of alternating current power, emergency procedures should be established for manually initiating and controlling the system under these conditions.

Since the water for cooling of the lube oil for the turbine-driven pump bearings may be

-10" dependent on alternating current power, design or procedural changes shall be made to eliminate this dependency as soon as practicable.

Until this is done, the emergency procedures should provide for an individual to be stationed at the tur-bine-driven pump in the event of the loss of all alternating current power to monitor pump bearing and/or lube oil tempera-tures.

If necessary, this operator would operate the turbine-driven pump in an on-off mode until alternating current power sources is restored.

Adequate lighting powered by direct current power sources and communications at local stations should also be provi.ded if manual initiation and control of the AFW system is needed.

(See Recommendation GL-3 for the longer-term resolution of this concern.)

3.

Recommendation GS The licensee should confirm flow path availability of, an AFW system flow train that has been 'out of service to perform periodic testing or maintenance as follows:

Procedures should be implemented to require an operator to determine that the AFW system valves are properly aligned and a second operator to indepen-,

dently verify that the valves are properly aligned.

The licensee should propose Technical Specifications to assure that prior to plant startup following an extended cold shutdown, a flow test would be performed to verify the normal flow path from the primary AFW

system water source to the steam generators.

The flow test should be conducted with AFW system valves in their normal alignment.

4.

Recommendation GS The licensee should install a system to automatically initiate AFW system flow.

For the short term, this system need not be safety-grade; however', it should meet the criteria listed below, which are similar to Item 2. 1.7a of NUREG-0578.

For the longer term, the automatic initiation signals and'ircuits should be upgraded to meet safety-grade requirements as indicated in Recommendation GL-l.

The design should provide for the automatic initiation of the auxiliary feedwater system flow.

The automatic initiation signals and circuits should be designed so that a single failure will not result in the loss of auxiliary feedwater system function.

Testabi lity of the initiating signals and ci rcuits should be a feature of the design.

The initiating signals and circuits should be powered from the emergency buses.

Manual capability to initiate the auxiliary feedwater system from the control room should be retained and should be implemented so that a single failure in the manual circuits. will not result in the loss of system function.

The alternating current motor-driven pumps and valves in the auxiliary feedwater system should be. included in the automatic actuation (simultaneous and/or sequential) -of the loads to the emergency buses.

The automatic initiation signals and circuits should be designed so that their failure will not result in the loss of manual capability to initiate the AFW system from the control room.

X.7.3.2 Additional Short-Term Recommendations The following additional short-term recommendations resulted from the staff's Lesson Learned Task Force review and the Bulletins and Orders Task Force review of AFW systems at Babcock 8 Wilcox-designed operating plants subsequent to our review of the AFW system designs at W-and C-E-designed operating plants.

They have not been examined for specific applicability to this facility.

1.

Recommendation

- The licensee should provide redundant level indications and low level alarms in the control room for the AFW system primary water supply to allow the operator to anticipate the need to make up water or transfer to an alternate water supply and prevent a low pump suction pressure condition from I'ccurring.

The low level alarm setpoint should allow at least 20 minutes for operator action, assuming that the largest capacity AFW pump is operating.

"13-2.

Recommendation

- The licensee should perform a jg-hour endurance test on all AFM system pumps, if such a test or continuous period of operation has not been accomplished to date.

Following the 72-hour pump run, the pumps should be shut down and cooled down and then restarted and run for one hour.

Test acceptance

'riteria should include demonstrating that the pumps remain within design limits with respect to bearing/bearing oil temperatures and vibration and that pump room ambient conditions (temperature, humidity) do not exceed environmental qualifi-cation limits for safety-related equipment in. the room.

3.

Recommendation

- The licensee should implement the following requirements as specified by Item 2. 1.7.b on page A-32 of NUREG-0578:

"Safety-grade indication. of auxiliary feedwater flow to each steam generator shall be provided in the control room.

The auxiliary feedwater flow instrument channels shall be powered from the emergency buses consistent with satisfying the emergency power diversity requirements for the auxiliary feedwater system set forth in Auxiliary Systems Branch

'Technical Position 10-1 of the Standard Review Pl'an, Section 10.4.9."

4.

Recommendation

- Licensees with plants which require local manual realignment of valves to conduct periodic tests on one AFW system train, and there is only one remaining AFW train available for operation should propose Technical Specifications to provide that a dedicated individual who is in communication with the control room be stationed at the manual instruction from the control room, this operator valves.

Upon would'ealign.

the valves in the AFW system train from the test mode,to its-operational alignment.

X.7.3.3 Lon -Term Recommendati.ons Long-term recommendations for improving the system are as'ollows:

Recommendation

- GL Licensees with plants having a manual starting AFW system, should install a system to automatically initiate the AFW system flow.

This system and associated automatic initiation signals should be designed and installed to meet safety-grade requirements.

Hanual AFW system star't and control capability should be retained with manual start 'serving as backup to automatic AF'W system initiation.

2.

Recommendation

- GL At least one AFW system pump and its associated flow path and essential instrumentation should I

automatically initiate.AFW system flow and be capable,.of being operated independently of any alternating current power source for at least 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.

Conversion of direct current power to

'alternating current is acceptable.

3.

Recommendation - The present method of supplying water from the alternate water sources to the CST for the AFWS requires consid-erable operator action and is estimated to take approximately g~z pz~ go zzcomp1~sg'he licensee should modify the design to provide means to supply water to the AFMS from the alternate sources within one-half hour, or less.

4.

Recommendation

- The St.

Lucie plant needs one full capacity train of AF>l flow (2 motor-driven or 1 turbine-driven AFW pump) for safe plant shutdown.

This AFMS design does not meet the high energy line break criteria in SRP 10.4.9 and Branch Technical Position 10-1; namely that the AFWS should maintain the capability to supply the required AFM flow to the steam generator(s) assuming a pipe break anywhere in the AFM pump discharge lines plus a single active failure.

The licensee should (1) complete an evaluation assuming such an event and determine any AFW system modifications or procedures necessary to maintain the required AFM flow to the steam generator(s),

or (2) describe how the plant can be brought to a safe shutdown condition by use of other available systems following such a

postulated event.

NOTE: ALLMOV'S FAILAS-IS LEGEND-rQ FO FAIL OPENED FC FAIL CLOSED FA FAILAS-IS NORMALLYOPENED NORMALLYCLOSED MOTOR OPERATED AIR OPERATED STEAM GENERATOR 1A 480V AC TRAIN AB STEAM GENERATOR 1B INSIDE CONTAINMENT OUTSIDE LO LO AB MAIN STEAM I MV-08-14 LO AB I-MV-09-7 NC AB I-MV-09-12 COiVTAIMMENT LO AB NC I-MV-08-13 I-MV-09-8 M

LO TRAIN AB LO LO LO NC A

I-MV-09-9 480V AC TRAIN A LO zg~

gO A

IL NC I-MV-09-13 480V AC TRAIN A I-MV-09-'l4 480V AC TRAIN B B

NC I-MV-09-10 480V AC TRAIN P LO NC I-MV-08-3 AB 125V DC TRAIN AB TO STEAM TURBINE AUX. FEED PUMP FROM SG BLOWDOWN hlQNITOR TANI<

FROM CITY WAl'ER TANI< S VIAWATER TREATMENT I'LANTOII FIRE I ROrLC rION SYSTEM CONDENSATEJ TANI<

LO 1A MOTOR LO LO 1C.

STEAM LO 125V DC l RAIN AB 1B MOTOR LO Auxiliary Feetlwater System St. Luele, URlt 1 Fiour~

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ENCLOSURE 2 Basis for Auxiliarv Feedwater System Flow Reaui remen.s As a result of rec nt staff revie;;s of operatin-plant Auxiliary Feed-water Systems (AFWS), the staff. concludes that the design bpses and criteria provided by licensees for establishing AFWS requirements for flow to the steam generator(s) to assure adequate removal of reactor decay heat are not well defined or documented.

We require that you provide the following AFWS flow design basis infor-mation as applicable to the design-basis transients and accident con-ditions for your plant.

l.

a.

Identify the plant transient and accident conditions considered in establishing AFWS flow requirements, including the following events:

1)

Loss of Main Feed (LHFW)

Z)

LMFW w/loss of offsite AC power 3)

LMFW w/loss of onsi,te and offsite AC power 4)

Plant cooldown 5)

Turbine trip with and without bypass 6)

Main steam isolation valve closure 7)

Mairi feed. line. break 8)

Main steam line break 9)

Small break LOCA 10)

Other transient or accident conditions not listed above b.

Describe the plant protection acceptance criteria and corres-oonding technical bases used for each initiating event identi-fied above.

The acceptance criteria should address plant limits such as

- Maximum RCS pressure (PORV or safety valve actuation)

- Fuel temperature or damage limits (DNB, PCT, maximum fuel central temperature)

CS cooling rate limit to avoid excessive coolant shrinkage

- Minimum steam generator level to assure sufficient steam generator heat transfer surface to remove decay heat and/or cool down the primary system.

2.

Describe the analyses and assumptions and. corPesponding technical justification used with plant condition considered in l.a.

above including:

a.

Maximum reactor power (including instrument error allowance) at the time of the initiating transient".or~.aocident.

b.

Time delay from initiating event to reactor trip.

c.

Plant parameter(s) which initiates AFWS flow and time delay between initiating event and introduction of AFWS flow into steam generator(s).

d.

Minimum, steam generator water level when initiating event occurs,.

e..Initial steam generator water inventory and'epletion rate before and after AFHS flow commences - identify reactor decay heat rate used.

0 1e f.

Maximum pressure at which steam is released from steam generator(s)

~

and against which the AFM pump must develop su ficient head.

1 g.

t1inimum number of steam generators that must receive AFM flow; e.g.

1 out of 2?,

2 out of '4'?

h.

RC flow condition - continued operation of RC pumps or natural circulation.

i.

Maximum AFM inlet temperature.

j.

Following a postulated steam or feed line break, time delay assumed to isolate break and direct AFW flow to intact steam P

generator(s).

AFM pump flow capacity allowance to accommodate the'ime delay and maintain minimum steam generator water level.

Also identify credit taken foe primary system heat removal due to blowdown.

k.

Volume and maximum temperature of water in main feed lines between steam generator(s}

and AFMS connection to main feed line.

l.

Operating condition of steam generator norma) blowdown following initiating event.

m.

Primary and secondary system water and metal sensible heat used for cooldown and AFM flow sizing.

n.

Time at hot standby and time to cooldown RCS to RHR system cut in temperature to size AFM water source inventory.

4

3.

Verify that the ARl pump-in your plant will supply the necessary flow to the steam generator(s) as determined by i tems 1

and 2

above considering a single failure.

Identify the margin in sizing the pump flow to allo", for pump recirculation flow-, seal leakage and pump wear.