ML18044A232

Advises of Requirements for Auxiliary Feedwater Sys.Forwards Detailed Listing of Applicable Requirements

ML18044A232
Person / Time
Site:	Palisades
Issue date:	10/30/1979
From:	Eisenhut D Office of Nuclear Reactor Regulation
To:	Bixel D CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.)
References
NUDOCS 7911150167
Download: ML18044A232 (27)

Text

r 1

• .UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555.

Docket No.

50-25~

Mr. David Bixel Nuclear Licensing Administrator Consumers Power Company 212.West Michigan Avenue Jackson, Michigan 49201

Dear Mr. Bixel:

October 30, 1979

• SUBJECT.:

NRC REQUIREMENTS FOR AUXILIARY FEEDWATER *SYSTEMS AT P.Al..ISAPES NUCLEAR PLANT The purpose of :this 1 etter is to advise you of our requirements for the a1.,1xiliary 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. 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 facility. contains a generic request for additional information regarding auxiliary feedwater system fl ow requirements.

The designs and procedures of the subject facility should be evaluated a.gainst 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 corranitment for implementation of required changes or actions should be provided.for NRC staff rev.iew within thirty days of receipt of this letter.

Also~ this schedule should indicate your date for submittal of information such as design changes, proced~re changes or Technical Specification changes to be provided for staff review.

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

~n 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* acc-ident as described *in the Combustion Engineering report CEN-114-P (Amendment 1-P)

Mr. David Bixel October 30, 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.

Enclosures:

As. stated

\\'\\

S\\ncerely,

~

'\\.

'~**

~filVl{

1,

\\ r Darrell G. Eise hut~cting Director Division of Operating Reactors Office of Nuclear Reactor Regulation

Mr. David Bixel cc w/enclosures:

M. I. Miller, Esquire Isham, Lincoln & Beale Suite 4200 One First National Plaza Chicago, Illinois 60670 Mr. Paul A.* Perry, Sec,retary Consumers Power Compariy 212 West Michigan Avenue Jackson, Michigan 49201 Judd L. Bacon, Esquire Consumers Power Company 212 West Michigan Avenue Jackson, Michigan 49201 Myron M. Cherry, Esquire Suite 4501 One IBM Plaza Chicago~ Illinois 60611 Ms. Mary P. Sinclair Great Lakes Energy Alliance 5711 Summerset Drive Midland, Michigan 48640 Charles Bechhoefer, Esq., Chairman Atomic Safety and Licensing Board Panel U. S. Nuclear Regulatory Commission Washington, D. c.

20555 Dr. George C. Anderson Department of Oceanography University of Washington Seattl~. Washington 98195 Dr. M. Stanley Livingston 1005 Calle Largo Santa Fe, New Mexico 87501 Kalamazoo Public Library.

315 South Rose Street Kalamazoo, Michigan 49006 October 30, 1979

X.6 (CE)

ENCLOSURE 1 PALISADES AUXILIARY FEEDWATER SYSTEM (AFWS)

X.6.1

System Description

X.6. 1. 1 Configuration - Overall Design

• A simplified flow diagram of Palisades AFWS is presented in Figure 1.

The AFWS includes a motor-driven pump and a turbine-driven pump, each capable of supplying 100% flow requirements for decay heat removal.

Each pump has a capacity of. 415 gpm at 2730 feet.

The pumps discharge to a common AFWS header which branches and connects to the main feed headers to each steam generator (SG).

Only one SG is needed to cool the* plant down to the temperature where the Shutdown Cooling system (SCS) can be used to bring the plant to safe shutdown.

The licensee estimates that the steam g~nerator would boil dry in 15 minutes without AFW fl ow following the worst case condition of loss of main feedwater with reactor trip.

The two pumps are located in the same room and could be rendered inoperable as a result of.a pipe break causing the flooding of the room.

The primary source of water for the AFWS is a 125,000 gallon condensate storage tan*k.

In addition, 75,000 gallons of water from the primary system make-up storage tank and 275 gpm from the make-up demineralizer system can be supplied to the condensate storage tank via pneumatic-operated valves which are opened from the control room.

The technical specifications

• require that a total of 100,000 gallons of water inventory be available for the AFWS.

The licensee estimates that this. inventory is approximately an 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> supply.

The tondensate storage tank is also connected to the main condenser hotwell through two make-up valves connected in parallel.

An alternate, long-term source of water to the AFWS, if needed, is from.

Lake Michigan and is directed to the AFWS pump suctions via the three fire protection system pumps.

Two of thefire pumps are driven by dedicated diesel engines and the other pump is driven by an electric motor which is powered from one of the two station emergency diese1 generators.

X.6. 1.2 Components - Design Classification The condensat~ storage tank is the only source 6f AFWS water which has a seismic Category l classification.

The steam turbine-driven auxiliary feedwater pump and associated steam inlet valves and piping is designed to withstand a 0.05 earthquake as stated in Appendix A of the FSAR.

The motor-driven auxiliary feedwater pump and associated piping and valves are classified seismic Category 1.

X.6. 1.3 Power Sources

• The motor-driven auxiliary feedwater pump is supplied from one of the two AC emergency buses.

The turbine-driven pump can receive motive-power steam from either steam generator.

--=----- The pneumatic-bperated valves in the discharg~ header of both pumps receive control power from separate AC vital instrument buses.

These buses are normally supplied from an AC emergency bus ~nd backed.up by the corresponding DC emergency bus via an inverter.

The pneumatic-operated valves in each steam line from the steam generator to the turbine-driven auxiliary feedwater pump are controlled from independent DC emergency buses.*

X~6.l.4 Instrumentation and Controls X.6. 1.4. l.Controls The AFWS is manually initiated and feedwater flow to the steam generator(s) is manually controlled.from the control room.

Steam generator level indication (nar~ow range only) is available to the operator in the control room.

The narrow range level channels ara designed in accordance with.

protection system requirements.

X.6. 1.4.2 Information Available to Operator System information available to the operator in the control room to assess the performance of the auxiliary feedwater system is as follows:

Status i ndi cat i ng 1 i ghts for the* motor driven auxiliary feedwater pump.

Position indication of auxiliary feedwater flow path control valves.

• Primary and secondary source water level indications.

Auxiliary feedwater flow indication.

Auxiliary feedwater pressure indication.

Steam pressure at inlet of turbine driven auxiliary feedwater pump.

Steam generator level.

X.6.1.4.3 Initiating Signals for Aut6matic Operation The auxiliary feedwater system is initiated manually from the control room.

In the event of a steam or feedwater (main or auxiliary) 1 i ne break, isolation of the auxiliary feedwater flow paths to the affected SG is accomplished manually.

Main steam line break isolation is accomplished automatically by the MSIV whereas feedwater line break isolation is accomplished manually.

A turbine trip will result in a reactor trip if reactor power is initially.

above 15 percent of rated power.

A reactor trip will always result in a turbine trip.

• X. 6. 1. 5 Testing Subsequent to the completion of this*review, the license has been amended to incorporate new Technical.Specification requirements as follows:

APPLICABILI'IY.

Applies to periodic testing requirements of the turbine-driven and motor-driven auxiliary feedwater pumps.

OBJECTIVE

• To verify the operability of the auxiliary feedwater system and its ability to respond properly when required.

SPECIFICATIONS

a.

The operability of the rrotor-and steam-driven auxiliary feed pumps shall be confirmed as required by Specification.4.3c.lf

b.

The operability of the auxiliary feedwater pumps' discharge valves CV-0736A and CV-0737A shall be confirmed at least every three (3) rronths.

1/

Specification 4.3c reads as follows:

Inservice testing of ASME Class 1, 2 and 3 pumi)s, as determined by 10 CF'R 50, Section 50.55a and Regulatory Guide 1.26 shall be performed in accordance with Section XI of the ASME Boiler and Pressure Vessel Code with applicable addenda as required by 10 CFR 50, Section 50.55a(g); except where specific relief has been granted by the NRC.

-.6 -

• --* X':°"6": l. 6

• Techni ca 1 Specifications The limiting conditions of operation are in accordance with the Technical Specifications as follows:

Steam and Feedwater Systems Applicability Applies to the operating status of the steam and feedwater systems.

Objective To define certain conditions of the steam and feedwater system necessary to ass*ure adequate decay heat removal.

Specifications The primary coolant shall not be heated above 325°F unless the following conditions are met:

a.

Both auxiliary feedwater pumps operable or one auxiliary feedwater pump and one fire pump operable.

b.

A minimum of 100,000 gallons of water in the condensate storage and primary coolant system makeup tanks combined and a backup source of additional water from Lake Michigan by the operability of one of the fire protection pumps.

• c.

All valves, interlocks and piping associated with the above components

• required to function during accident conditions, are operable.

d.

The main steam stop valves are operable and capable of closing in five seconds or less under no-flow conditions.

The licensee has committed to implement the following plant operating

_procedures, until an approved Technical Specification revision in this regard is established:

With the primary coolant system temperature greater than 325°, both auxiliary f eedwater pumps and one fire pump wi 11 be operable except as fo 11 ows:

a.

One auxiliary feedwater pump may be i~operable for a period of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

b.

The firewater makeup to the auxiliary feedwater pump suction may be inoperable for a period of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

If an inoperable auxiliary feedwater pump is not restored to service in 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, the plant will be placed in hot shutdown within the next 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />.

The licensee has proposed Technical Specification changes in this regard which are under staff evaluation.

x. 6. 2. l X.6.2.2 Reliability Evaluation Results The Palisades AFWS consists of two full capacity subsystems, either of which, when delivering its pump capacity, can provide for adequate decay heat removal.

The system is manually actuated from the plant control room.

The failur~ modes expected to dominate the.overall demand unavail-bility of the AFWS were assessed given three transient events for which operation of the AFWS would be required.

The dominant failure modes for these th~ee tr~nsient events are summarized below:

Loss of Main Feedwater (LOFW)

The dominant failure mode assessed for the AFWS design for this transient was failure of the plant operator to start at least one of the AFW system trains.

This potehtial failure mode ~as stimated to contribute roughly 90% to the AFWS unavailability.

The next level of dominant failure modes identified was principally composed of double faults.

These double faults included:

(1) failures in the turbine and electric pump trains due to hardware faults or al,l owed maintenance outages, and (2) inadvertent closure of manual valve (A) from the condensate storage tank to the pumps sucton and not reopening this valve or, as backup, the operator failing to activate the fire water supply to the AFWS before pump damage occurs.

LOFW and Loss of Offsite AC Power (Only Onsite AC Power Available) the OOmina.nt faults identified for this transient were essentially the same as described above.

X.6.2.3 LOFW ~ith Only DC Power Available The dominant failure modes identified for this given event were (1) operator failing to actuate system from the control room and (2) demand failures in the turbine train due to single hardware faults and to the allowed outage time for this train of AFWS.

For this LOFW ~vent, it was noted that air

• operated valves (E) and (F) in the steam supply line for the turbine driven pump tould eventually fail close after being actuated open.

These valves fail closed on loss of air supply and with time, the air supply in the air accumulator could decay to a point where the valves would close.

The operator can, however, manually open these valves (locally) and reestab-lish operation of the turbine driven pump.

If the plant operator fails to do this, the AFWS will experience delayed failure.

X.6.2.4 Principal Dependencies/Interaction Identified X.6.3 The principal dependencies are described above.

One other potential*

interaction identified is due to the fact that both AFWS pumps are located in the same room~ Thus, the pumps appear vulnerable to flooding.

No high energy lines were said to.exist within this room; however, the room has flooded in the past to a depth of about six inches due to lack of flowthrough the floor

• drain.

The room is current being i)1spected f0r flooding every shift.

Recommendations for this Plant The short-term recommendations (both ~eneric, denoted by GS, and plant-specific) identified in this section represent.actions to improve AFW system reliability that should be implemented by January 1, l9_BQ, or as

x. 6. 3. 1 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 (both generic, denoted by GL,.and plant-specific) identified in this section involve system designevaluations and/or modifications to improve AFW system reliability and represent actions that should be implemented by January 1, 1981, or as soon thereafter as is practicable.

Short-Term

1.

Recommendation GS The licensee should lock open single valves or multiple valves in series in the AFW-system pump suction piping and lock open other single valves or multiple valves in series that ~ould interrupt all AFW flow.* Monthly inspections should be performed to verify that these valves are locked and in the open position.

These inspections should be proposed for incorporation into the surveillance requirements of the p 1 ant Techni ca 1 Specifications..See Recommendation GL-2 for the longer term resol~tion of this concern.

2.

Recommendation GS Emergency procedures for transferring to alternate sources of AFW supply should be available to the plant operators.

_These 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:

'111ose 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, In case in which the primary water supply is being depleted.

The procedure for this cas~ should provide for transfer t6 the alternate water sources prior to.draining of the primary water supply~

3.

Recarrmendation 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 independently 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 auto-matically 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.l.7a of NUREG~0578.

For the longer term, the automatic initiation signals and circuits ~hould be upgraded to meet safety-grade requirements as indicated in Recommendation GL-1.

• 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.

Testability of the initiating signals and circuits should be a feature of the design.

The initiating signals and circuits s~ould 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.

5.

Recommendat.ion The licensee should verify that the air accumulator will hold the air operated valve~ in the turbine driven pump steam supply line open for at least two hours following loss of all AC power.

6.

Recommendation - The motor driven pump and the pneumatic-operated valve(G) through which AFW flow to steam generator A is controlled receive motive and control power from Division I emergency buses.

Pneumatic valve (F), which supplies steam from steam generator A to the turbine driven AFW pump, receives control power from a Division II emergency bus.

Similarly AFW flow control valve (H) and steam supply valve (E) associated with steam generator B receive power from Division II and I emergency buses resp~ctively.. Upon loss of air or power, the AFW flow control valv~s (G) and (H) fail open and the turbine driven pump steain admission valves (E) and (F) fail closed *.

It is recognized that the AFW flow control valves are designed to fail open upon loss of air or power so that AFW flow to the steam generators should be assured:

However, it cannot be concluded that all failures will result in opening these valves.. Degradation of Division I buses could potentially result i~ loss of the eritire AFW system.

The licensee should analyze the consequences of Division I voltage degradatiori as well as other failures (e.g., restricted air flow) to assure that there is no Division I failure mode that can result in loss of the entire AFW system~ Until this analysis is completed or the AFW system is modified to preclude such an occur-rence, emergency procedures should be prepared to retain AFW system capability.* (See long term recommendation 4.b).

7.

• Recommendation - Each steam generator has two pneumatic-operated atmospheric steam dump valves connected in parallel~ These four valves have the same controller which presumably receives power from only one source, and therefore is vulnerable to a single failure event.

Concern was expressed to the licensee as to whether the steam supply to the turbine AFW pump is adversely affected by the potential simultaneous opening of all atmospheric dump valves due to a single failure at the controller or its power source~ The licensee has indicated that the pressure drop acn::>ss the valves is sufficiently l~rge to assure adequate steam supply"t6 the turbine driven pump from the steam generators.

We require that the licensee provide analyses to confirm this assertion.

(See long term recommendation 4a.)

X.6.3.2 Additional Short~Term Recommendation~

The following additional short-term recommendations resulted from the staff's -Lessens Learned Task Force review and the Bulletins and Orders Task Force review of AFW systems at Babcock & Wilco~-designed operating plants subsequent to our review of the AFW system designs at ~- 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 indica-tions 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 occurring.

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

2.

Recommendation - The licensee should ~erform a 72-hour endurance test on all AFW 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 criteria shoul~

include demonstrating that the pumps femain within design limits with respect to bearing/bearing oil temperatures and vibration and that pump room ambient conditions (temperature, humidity) do not exceed e~vironmental qualification limits for safety-related equipment in the room.

X.6.3.3

- 16* -

3.

Recommendation - The licensee should implement the following require-ments as specified by Item 2. l. 7. b on page A-32 of NUREG-0578:

. "Safety-grade indiction of auxiliary feedwater flow to each ste~m 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 Plan, Section 10.4.9.11

4.

Recommendation - Licensees with plant~ w~ich require loc~l manual

• realignment of valves to conduct periodic test 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 ro.om be stationed at the manual valves.

Upon instfuction from the control room, this operator would realign the valves in the AFW system train from the test mode to its operational alignment.

Long-Term Long-term recommendations for improving the system are as follows:

1.

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.

Manual AFW system start and control capability should be retained with manual start serving as backup to automatic AFW system initiation. *

2.

Recommendation GL Licensees with plants in which all (primary and alternate) water ~uplies to the AFW systems pass thro~gh valves in a single flow path should install redundant parallel flow paths (piping and valves).

Licensees with plants in which the primary AFW system water supply passes t~rough valves in a singla flow path, but the alternate AFW sy~tem water supplies connect to the AFW system pump suction piping downstream of the above valve(s) should install reduhdant valve(s) from the alternate water supply upon low pump suction pressure.

The licensee should propose Technical Specifiations to incorporate appro-priate periodic inspections to verify the valve positions.

3.

Recommendation - The licensee should evaluate the following concerns:

a.

The discharge lines of both AFW pumps combine into a single header through which all AFW water must flow.

A pipe break in this single flbw path coOld result in tha loss of the entire AFW system function.

b.

The Palisades AFW system design does not meet the high energy line break criteria in SRP 10.4.9 and Branch Technical Position 10-1; namely, that the AFW system should maintain the capability to supply the required AFW flow to the steam generator(s) assuming a pipe break anywhere in the AFW pump discharge lines concurrent with a single active failure.

The licensee should ~valuate the postulated pipe breaks stated above and (1) determine any AFW system design changes or procedures necessary to detect and isolate the break and direct the required feedwater fl ow to the steam generator( s) before they boil dry or (2) describe how the plant can be brought to a safe shutdown condition by use of other systems which would be available following such postulated events:

4.

The licensee should evalute the following concerns:

a.

Each steam generator has two pneumatic-operated atmospheric steam dump ~alves connected in parallel.

These four valves have the same controller which presumably receives power from only

.one source.

The consequences of single failures would be reduced by supplying power to the dump valves of each.steam generator from separate power divisions.

(See short-term recommendation 7).

6.3.4 b.

This concern is a follc:w-up to that in short-teTin recorranendation 6, (i.e., loss of the AfWS due to a degraded power system division).

Valves (G) and (F) are both in AfWS train A but receive power from different DC divisions as do valves (E) and (H) which are in AfWS train B.

Thus, the effect of degradation of one power division would be reduced by having valves ( G) and ( F) powered from the same division; similarly for valves (E) and (H)~

c.

Wide range steam generator level instrumentation is not provided in the control room.

Evaluate the need for such instrumentation to facilitate proper operator action considering transients and accident conditions.

Based on the results of the above evaluati~ns, the licensee sh6uld (1) determine any AFW system design changes necessary to mitigate the concern or (2) describe how the plant can be brought* toa safe shutdown condition by use of other systems which would be available following such postulated events.

Considerations Based on the Systematic Evaluation Program The following items are under review by the Systematic Evaluation Program (SEP) and supplement the above long-term recommendations.

1.

The Palisades Plant including the AFWS will be reevaluated during the SEP with regard to internally and externally generated missiles, pipe.

whip and jet impingement, quality and seismic design requirements,

• earthquakes, tornadoes, floods, and the failure of nonessential systems.

2.

The staff will reassess the need for a water level alarm system in the AFWS pump room.

3.

The Palisades AfWS is not automatically initiated and the design does.

not have capability to automatically terminate feedwater flow to a depressurized steam generator and provide flow to the intact steam generator.

This is accomplished by the control room operator.

The effect of this provision will be assessed in the main steam line break evaluation for *Palisades.

4.

A lack of system redundancy exists because the turbine-driven AFWS pump is not seismic Class l.

The staff will consider the need. for upgrading the seismic cl~ssification of the pump in the SEP integrated assessment of Palisades.

5.

The staff will assess the need for increasing the technical specification inventory limit for the seismic Class I AFWS water supply.

LEGEND:

M-D MOTOR DRIVEN T-D TllRl31NE DRIVEN IX]

NORMALLY OPEN

.~

NORMALLY CLOSED

I; AIR OPERATED SG STEAM GENERATOR l,i I, Ill POWER DIVISIONS A

ALTERNATING CURRENT D

DIRECT CURRENT TB TURBINE FO FAIL OPEN.

FC FAIL CLOSE FAI FAIL AS IS NOTES:

VALVES POWERED FROM SAME D-C EMEl1GENCY BUS

• • VALVES POWERED NORMALLY FROM SAME NON SAFETY A-C BUS. MANUAL BACKUP TRANSFEB CAPABILITY OF TllE NON SAFETY BUS TO AN EMERGENCY SOURCE NO CONTROL POWER REOUI RED 12"

<i u..

CONDENSATE STORAGE TANK 6"

CONDENSER HOTWELL Auxiliary Fecclwilter System Palisades Figure 1 (Al PRIMARY SYSTEM MAl<E-UP STORAGE TANK I-AID FROM MAl<E-UP DIMINEl1/\\LIZEl1 SYSTEM TO 1-D ATMOSPHERE....---..i-....

FO FC FC

~...

B A

SG SG

ENCLOSURE 2.

BASIS FOR AUXILIARY FEEDWATER SYSTI:M.FLOW FEQUIREMENTS As a resUlt of r:>ecent staff reviews of operating plant auxiliary feedwater systems (Afi.,1S), the staff concludes that.the design bases and criteria provided by licensees for establishing AFWS requirements for flc:M to the stec:zn ge.rierator( s) to assure ade-quate rem:Jval of reactor decay heat are not well defined or documented.

We require that you provide the :follc:Ming AIWS flow design basis infonnation as appli-cable to the design basis transients an<i accident conditions for your plant.

1. a.

Identify the plant transient and accident cor;:i.tions considered in estab-lishing AIWS flc:M requirements, including the follcwing events:

1)

Loss of Main Feed (L.~)

2)

U1FW w /loss of *off site AC. power *

• 3)

LMFW w/loss of offsite and onsite AC power

4)

Plant c6oldcwn 5 Y Turbine trip with and ~ithout bypa.Ss

6)

Main steam isolation valve closure

7)

Ma.in: feed line break

8)

Main steam line break

9) ~

break LOCA

10) Other transient or accident conditions not listed above.

I

b.

Describe the plant protection acceptance criteria and corresponding techni-cal bases used for each initiating event identified above. The acceptance criteria should address plant limits such as:

Maximum RCS pressure (PORV or safety valve actuation)

- Fuel temperature or damage l:imi ts (DNB, PCT, max:imum fuel central tempera"'c..

- RCS cooling rate limit to avoid excessive coolant shrinkage

- l"iin:imum steam generator level to assure sufficient steam generator heat t.::

fer.sur..face*to*remove decay. heat and/or coolda..m the primary system.

2... _ Describe ~'le analyses and assumptions and corresponding technical j'.JS"tif ication used with pla,nt conditions considered in l.a. above including:

a.

MaxiJ!!'~ reactor power (including instrument error allcrwance)*at the time of the i.'l"litiating transient or accident.

• b.

Tilre delay from initiating event to reactor trip.

c. Plant parameter( s) which initiates Ar--WS flovi and time delay between ini tiat-

. ing event and introduction of.AfWS flow into steam generator( s).

d.

Minimum steam generator water level when initia::ing event occurs.

e. Initial steam generator water inventory and dE: _;letion rate before and after

.AFWS flow cormnences - identify reactor decay heat re.te used.

f.

Maximum pressure at which steam is released from steam generator(s) and agains~,

which the.AFW pump must develop sufficient head.

g~

Minimum *number of steam generators that must receive Pu~ flew, e.g., l of 2, 2 of 4?

h.

RC flow condition - continued *operation of RC pumps or natural circulation~

i. Max:L11Ulll AFvJ inlet temperature.

j. Follcrwing.*a postulated steam or feed line break, time delay assumed to isoiate break and direct AJW flow to intact steam generator( s).

M'W pump flow capaci t:

allo,,,;ance to accorrodate

• the time delay and maintciin minimum steam generator

• water level. Also identify credit taken for primary system heat reiroval due to blowdown.

k.

Volume and ffi3Xi.nu.lm temperaturie of water in main feed lines between steam generator(s) and.AfWS connection to main feed line.

1. Operating condition *of steam generator normal blavdo-wn following initiating event.

m.

?ril..=r; and secondary system water and metal sensible heat used for cooldcrVlln and.:::.Z..*J flow sizing.

n.

Ti.Te at hot standby and time to cooldaw'I1 RCS to R'!..ffi (or SCS) sys~em cut in te;r9era:ture to size AfiJ water sc1..l.l-ice inventory.

3 -

• -J,.-. Verify th~t ~l-ie AIW pumps iri your plant will supply the necessary flow to the steam generator(s) as determined by items 1 and 2 above considering a single failure. Identify the margin in sizing the pump flow to allow for pump recir-culation flaw, seal leakage and pump wear.