ML20206H977

Proposed Tech Specs Modifying Licensing Basis for EDG on- Site Diesel Fuel Storage Requirements & Corresponding TSs

ML20206H977
Person / Time
Site:	Pilgrim
Issue date:	05/05/1999
From:	BOSTON EDISON CO.
To:
Shared Package
ML20206H970	List: ML20206H965 ML20206H977
References
NUDOCS 9905120070
Download: ML20206H977 (14)

Text

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ATTACHMENT B - BECo L*tter 2.99.029 MARKED-UP UFSAR AND TECHNICAL SPECIFICATION PAGES I 0FSAR'PAGES (total five pages)

Page 8.5-1 .

Page 8.5-2 1 Page 8.5-8 Table 8.5-3, page 1 of 1 Page 8.10-1 TECHNICAL SPECIFICATION PAGES (total three paces)

TS Page No. 3/4.9-1 (Revised TS 3.9.A.3)

TS Page No. 3/4.9-3 (Revised TS 4.9.A.1.d)

TS Page No. B3/4.9-1 (Revised Bases 3.9 for Auxiliary Electrical System) l 9905120070 990505 I PDR ADOCK 05000293 P PDR j 9

r 8.5 STANDBY AC POWER SOURCE

'8.5.1 Scfety Objectiva The safety objective of the standby ac power source is to provide a single failure proof source of onsite ac power adequate for the safe shutdown of the reactor following abnormal operational transients and postulated accidents.

8.5.2 Safety Design Basis e

1. The Standby AC Power System consists of two independ'ent ac power sources that are self-contained within the station site and which l are independent of offsite power sources.

2. Each standby generator unit is capable of providing sufficient power to its emergency bus, upon failure of all offsite power, to satisfy the load on the bus. fI T

3. Each standby generator unit is designed in accordance with Class I a ,

criteria.

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4. The generator sets are capable of automatic starr at any time and and

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capable of continued operation at rated load, voltage, E frequency until manually stopped. 5 ,

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5. The generator sets have the ability to pick up loads as described 3

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\ on Table 8.5-1 in the sequence and time period outlined on Table j a.

I 8.5-2. 2 1

m l 6. The generators are capable of being independently synchronized for T

, parallel operation with the unit auxiliary transformer or the { i

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( startup transformer (preferred ac power source). This g>

l synchronization is done manually for system performance tests. $* s

! Provisions were made in the design to prevent: (a) the electrical l interconnection of both generators and (b) the electrical g 4 interconnection of either generator with the secondary ac power y ,

l

)

source.

k-8

7. Each engine generator unit has a unit fuel storage (day tank) {g*

tank. Each day tank is supplied from its main fuel storage tank. j8 Provisions are madep et beth --th sucti n and dischcrs: ef the j Sl transitr pupp*_fer :r::: ceus.ecting the_ ..e. uiolly ind:Fnd;nt fuc-1 l h; eil :yrt - by ep ning aerrally cles_ d manual .ol m . Tus.che.r ( g5.

l Jet:il cre ch % v_n r q;ut e v., . . %g A hydroturbine, driven by F Diesel Fire Pump P-140 drives the Backup Diesel Fuel Transfer Pump

.)*

Eg (P-181). This pump takes suctir r rem th emergency diesel {SSy h r,enerator iuct oil stoiage tanks, bypasses Die r,e l. T rans f e r Pump P g j p 141A 1 and d i s c h a i r,e : to Day Tank T-123. The purpose at thit [g hydrocurbine criven pump is to provide a redundant (non-electric m4 ~

power dependent) diesci fuel oil transfer pump for the Diesel Firi- g Pump P 140. This redundant pump will allow extended operation of v; E

,e 6 the diesel fire pump as a water source for the RHR system during extended station blackout and severe accident scenarios beyond Eto 8.5-1 Revision 11 - July 1990

/ INSERT A. . . NW to refill the EDG storage tanks from the two station blackout diesel generator storage' tanks. The combined on-site diesel fuel supply provides continuous seven days operation of both EDGs at full rated capacity.

_m

,v n

y s Jr$y5 b design basis. Each main fuell-terr c t:-! is capible of providing

. sufficient fuel for seven eration of one engine gsnarator unit undar postulated accidsnt conditions. Each day tank provides enough fuel for a minimum of 2.5 hrs of full load operation of the engine generator unit.

M Control power required for the startup and operation of each unit (0 is supplied from the 125 V station DC Power System. Other auxiliaries necessary to ensure continuous operation are supplied as required from the diesel generator through the' emergency service buses.

[. The units are capable of being started or stopped manually from g local control stations near the engines or remotely started from the control room. The engines are normally connected to the emergency service buses from the control room. The engines start automatically upon the loss of both the preferred power source and the unit auxiliary power source or low-low reactor water level, or high drywell pressure.

)d. The Standby AC Power System conforms to the applicable sections of lfJ- IEEE-308, Standard Criteria for Class IE Electrical Systems for )

Nuclear Power Generating Stations. l

. Provisions shall be included to minimize the probability of p losing power from the remaining sources as a result of, or coincident with the loss of power generated by the unit, loss of power from the transmission network, or loss of power from the onsite electric power supplies. .

1 8.5.3 Description There are two normal power sources available to each 4,160 V emergency bus; the unit power source and the preferred power source (startup transformer). A fourth power source is from the secondary power l source discussed in Section 8.3. This source is a backup to the standby diesel generator. The breaker is interlocked to prevent synchronization or interconnected with the diesel generator, or with the normal power sources. The loss of the unit power source results in automatic fast transfer to the preferred power source. The loss of both the startup transformer source and the unit auxiliary power source to either emergency service bus results in automatic starting of the diesel-generator associated with that bus. The diesel generator supply breaker will close approximately 10 sec later, if the diesel generator has reached rated speed and voltage. The diesel generator, the third power source, now supplies power to the affected emergency bus ,

1 The following < rents occur under Loss of Coolant Accident (LOCA) conditions in the order indicated: l l

1. The diesel generators are automatically started (independent .

of availability of offsite ac power) l 8.5-7 Revision 16- . lune 1994

We~1EcFIRemng rehays (Groups 2, 3, and 4) for each diesel generator are 7l

. leestad in aspereta asetiens (SA cnd SB) of an additional esin centrol room jf $$ l v . p:nal which h2a throe wiring asetions (SA, SB, end SX) separated by fire g2iV r b:rrists. Soma snginaarsd s fsgucrd loads cra affected by thsee relays end the ir ui s__will_be tested periodically. 58"5 l]lig l

._ h Y Ofel FIch ' diem generator W $b W s capable of starting and continuously operating

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F *a1-t:f __

_ . . . _..ditir .: for a period of 7 days using fuel stored onsite in underground storage tanks. fThe starting air supply is jN "F o h stored in receivers and maintained at proper pressure. Independent sources ~jf f ,E. l I

of 125 V de power are used to supply electrical control power to the air ig>g~5=

starting system for diesel generator units. See Section 8.6.4 for a more

• EE 8 detailed description of the 125 V system.

1 The units and all necessary 2

,q i auxiliaries are housed in Class I structures, c

1. j 8f.{ l

' $2 The engineered safeguard loads are divided between the two 4,160 V jj emergency service buses so that the failure of one diesel generator or one' x ;;;!

4,160 V emergency service bus would not provent a safe shutdown of the 3glg reactor. Each diesel generator and its associated system is separated so gE 3<e3y 4

that failure of any one component will not affect the operation of the redundant system. c 2 ,

G The capability of the diesel generator to start and attain rated voltage g

\

i and frequency within 10 sec, to accept the necessary engineered safeguard 2 l loads, and to start and accelerate the emergency core cooling system pumps IF* I in the required time, meets the necessary requirements for the standby ac O

V power system, 8.5.5 Inspection and Testing

]h 3 3 3

3 Since the diesel generators are utilized as standby units, readiness is of bEw aee prime importance. Readiness can best be ' demonstrated by periodic tesf16gI E f j 8,c which insofar as practical, simulates actual emergency conditions. The [g, a _ E T>

' testing program is designed to test the ability to start the system as well (.E "E as te run under load for a period of time long enough to bring all?je#3 fl g

l components of the system into equilibrium conditions to assure that cooling y p @- @8 and lubrication are adequate for extended periods of operation. Functional ,iS o E 8 1 tests of the automatic ' circuitry are conducted on a periodic basis to %l demonstrate proper operation. '

Provisions are included for manual synchronization of an individual diesel generator unit with the unit auxiliary transformer or the startup transformer to provide the capability to functionally test the diesel ,

generat.or performance at full rated outpur.- 1 Interlocks are provided to preclude the synchronization or interconnection of both diesel generators with each other, or of either diesel generator with the secondary ac pover source An initial system test wilt be potformed to de . ans t i ..t e t h.u t h, standby at power system can start and accept design load within the design basis time.

O 8.5 8 lie v i s i on 1/ June 1995

, TABLE 8.5 3

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STANDBY AC POWER SOURCE EQUIPMENT LIST ,

. Diesel Engine Rated Speed 900 rpm Continuous Rated Capacity 2,600 kW '

Overload capacity 2,750 kW for 2,000 ht;/yr Maximum Overload Capacity .3,000 kW for 2 hr/yr Fuel Consumption at Rated Capacity .0764 gal /kW-hr Cenerator Continuous Rated Capacity 2,600 kW Power Factor 0.8 Frequency 60 Hz Voltage 4,160 V Phase (connection) 3 (wye) overload capacity 2,860 kW for 2,000 hr/yr 3,250 kW for 30 min / day 3,900 kW for 1 min / day tO Q Exciter l Size 21 kW Diesel Generator Startup Starting time to rated speed and voltage, and ready to accept load $10 sec l

Starting time to rated load $30 sec l 64di h Fuel Oil Storage D'~\

Day Tank greater than 600 galf ems l Mate-Storage Tank 25,000 gallerwS ( Q )

g. ..- .

9 6 0 D (y hWye. QMNJ 10,000 y T (%c&

I 1 of 1 Revision 15- June 1993

, 8.,10.1 Power Cencration Objective

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Tha Blackout AC Powar Source consists of an indepsndant diesel generator which provides a non-safety related source 'of onsite AC power to the 4.16kV emergency service buses through a two breaker 4.16kV bus in the qvent of a station blackout.

l 8.10.2 Power Generation Design Basis i

1. The blackout diesel generator has the capacity to carry the load \

associated with one of three ECCS pumps on either emergency service bus A5 or A6 and all associated loads on that train / I required for loss of offsite power without a lhCA. Some loads q associated with buses AS or A6 (See Table 8.10-1 for ratings) are one salt service water pump (SSW), one reactor buildin6 closed 3 cooling water pump (RBCCW) and various electrically operated d valves. Operator action is required to limit blackout diesel generator loading and automatic start of the 4kV-ECCS pumps. '

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2. The Blackout AC Power Source is completely self-contained, not relying on any permanent system for operation. The blackout diesel generator is mounted on a skid and housed in a pre-hhk

,j I

engineered enclosure for protection from the environment. The unit is capable of providing rated power (See Table 8.10-2) for a

{

minimum period of one week without refueling. t  %

M

3. Maintenance loads for the blackout diesel generator are provided [ ]

by a 480V feed from the station during normal operations.

However, upon loss of power, the unit is capable of "blackstart" o \

automatically picking up the maintenance loads. The Blackout AC j Power Source is a manual start system either from the main control room or locally from the diesel enclosure. D l 5 @ '

4. The Blackout AC Power Source will operate in parallel with the j y shutdown transformer during load testing of the blackout diesel. .,

8.10.3 Description

)* A i

l The Blackout AC Power Source is connected to PNPS through a two breaker 41 4.16V bus A8 with the blackout diesel generator connected to the first breaker, A801 and the shutdown transformer secondary connected to the T d cecond breaker, A802r- The 4.16V bus A8 is connected by cable to breaker A .i A600 of the emergency service buses. Power from the secondary ac power i A dk source (shutdown transformer or the blackout diesel generator) to the 4.16kV emergency service buses is controlled by breakers A600, A501 and A601. '

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The controls of circuit breakers A801 and A802 are interlocked to prevent interconnection of the diesel generator with the shutdown transformer except for testing of the diesel generator. The blackout diesel generator is interlocked, as is the shutdown transformer, to prevent operation in parallel with the unit AC power source, the preferred offsite power source, or the standby AC power source 1

8.10-1 Revision 16 June 1996 I

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LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS l I

3.9 AUXILIARY ELECTRICAL SYSTEM 4.9 AUXILIARY ELECTRICAL SYSTEM Apolicability: Acolicability:

Applies to the auxiliary electrical power Applies to the periodic testing requirements system. of the auxiliary electrical systems.

Objective: Obiective: ,

To assure an adequate supply of electrical Verify the operability of the auxiliary power for operation of those systems electrical system.

required for safety.

Specification: Specification:

]

A. Auxiliary Electrical Eauipment A. Auxiliary Electrical Eauipment Surveillance The reactor shall not be made critical 1. Diesel Generators  !

unless all of the following conditions are j satisfied a. Each diesel generator shall be '

manually started and loaded once l

1. At least one off-site transmission line each month to demonstrate I and the startup transformer are available operational readiness. The test shall I and capable of automatically supplying continue for at least a one hour l auxiliary power to the emergency buses. period at rated load.  ;

2. An additional source of off-site power During the monthly generator test the  !

consisting of one of the following: diesel generator starting air compressor shall be checked for

a. A transmission line and shutdown operation and its ability to recharge transformer capable of supplying air receivers. The operation of the power to the emergency 4160 volt diesel fuel oil transfer pumps shall be I buses, demonstrated, and the diesel starting time to reach rated voltage and

b. The main transformer and unit frequency shall be logged.

auxiliary transformer available and capable of supplying power to the b. Once per operating cycle the emergency 4160 volt buses, condition under which the diesel generator is required will be simulate I

3. Both diesel generators shall be and test conducted to demonstrate operable. Each diesel generator shall that it will start and accept the have a minimum oi 4&r800 36,80Q emergency load within the specified gallons of diesel fuei on site. N time sequence. The results shall be Of this volume, at least 19,800 gallons of logged.

fuel shall be stored in each EDG Class I fuel system. The balance of the 36,800 gallons /EDG shall be available in the Station Blackout diesel generator tanks.

PNPS 3/4.9-1 Amendment No. 479 l 1

LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.9 AUXILIARY ELECTRICAL SYSTEM 4.9 AUXlLIARY ELECTRICAL SYSTEM A. Auxiliary Electrical Eauipment (Cont) A. Auxiliary Electrical Eauipment Surveillance

4. 4160 volt buses A5 and A6 are (Cont) on-site energized and the associated 480 volt d. Once a month t uantity of diesel buses are energized. fuel availabl all be logged.

5. The station and switchyard 125 and 250 e. Once a month a sample of diesel fuel volt batteries are operable. Each battery shall be checked for quality in shall have an operable battery charger, accordance with ASTM D4057-81 or D4177-82. The quality shall be within

6. Emergency Bus Degraded Voltage the acceptable limits specified in i Annunciation System as specified in Table 1 of ASTM D975-81 and I Table 3.2.B.1 is operable. logged.

7. Specification: 2. Station and Switchyard Batteries .

l Two redundant RPS Electrical Protectio a. Every week the specific gravity, the Assemblies (EPAs) shall be operab!e at voltage and temperature of the pilot all times on both inservice power cell and overall battery voltage shall supplies. be measured and logged.

Action b. Every three months the measurements shall be made of

a. With one EPA on an inservice power voltage of each cell to nearest 0.1 supply inoperable, continued volt, specific gravity of each cell, and operation is permissible provided that temperature of every fifth cell. These the EPA is retumed to operable measurements shall be logged.

status or power is transferred to a source with two operable EPAs within c. Once each operating cycle, the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. If this requirement cannot stated batteries shall be subjected to be met, trip the power source. a Service Discharge Test (load profile). The specific gravity and

b. With both RPS EPAs found to be voltage of each cell shall be inoperable on an inservice power determined after the discharge and supply, continued operation is logged.

permissible, provided at least one EPA is restored to operable status or d. Once every five years, the stated poweris transferred to a source with batteries shall be subjected to a at least one operable EPA within 30 Performance Discharge Test minutes. If this requirement cannot (capacity). This test will be performe be met, trip the power source.

in lieu of the Service Discharge Test reqWements oMA22 abe.

NOTE: Only applicable if tripping the power source would not result in a scram.

PNPS 3/4.9 3 Amendment No. 4-79

I BASES:

3.9 AUXILIARY ELECTRICAL SYSTEM l

. The general objective of this Specification is to assure an adequate source of electrical l power to operate the auxiliaries during plant operation, to operate facilities to cool and l lubricate the plant during shutdown, and to operate the engineered safeguards '

following an accident. There are three sources of a-c electrical energy available; namely, the startup transformer, the diesel generators and the shutdown transformer.

The d-c supply is required for switchgear and engineered safety feature systems.

Specification 3.9.A states the required availability of a-c and d-c power; i.e., an active off-site a-c source, a back-up source of off-site a-c power and the maximum amount of on-site a-c and d-c sources.

INSERT NEXT PAGE The di :e! fue! Supp!y con:!:t Of two (2) 25,000 g:!!One tanke. Leve! instrument: tion provide: Operators the inf0=:t!On neces:Orj to ensure a minimum supp!y of 19,800 g:!!One i:MacMa4 Auxiliary power for PNPS is supplied from two sources; either the unit auxiliary transformer or the startup transformer. Both of these transformers are sized to carry 100% of the auxiliary load. If the startup transformer is lost, the unit can continue to operate since the unit auxiliary transformer is in service, the shutdown transformer is available, and both diesel generators are operational.

If the startup and shutdown transformers are both lost, the reactor power level must be reduced to a value whereby the unit could safely reject the load and continue to supply auxiliary electric power to the station.

In the normal mode of operation, the startup transformer is energized, two diesel generators and the shutdown transformer are operable. One diesel generator may be allowed out of service based on the availability of power from the startup transformer, the shutdown transformer and the fact that one diesel generator carries sufficient I engineered safeguards equipment to cover all breaks. With the shutdown transformer and one diesel generator out of service, both 345kV supply lines must be available for the startup transformer.

Upon the loss of one on-site and one off-site power source, power would be available from the other immediate off-site power source and the one operable on-site diesel to carry sufficient engineered safeguards equipment to cover all breaks. In addition to these two power sources, removal of the isolated Phase Bus flexible connectors would allow backfeed of power through the main transformer to the unit auxiliary transformer and provide power to carry the full station auxiliary load. The time required to perform this operation is comparable to the time the reactor could remain on RCIC operation before controlled depressurization need be initiated.

l l

l Rev!:icn177 Amendment No. 140,143 B3/4.9-1

INSERT TO B3.9 to Pace B3/4.9-1 ,

The on-site diesel fuel supply system consists of two (2) 25,000 gallons Class i EDG i storage tanks and two (2) 20,000 gallons Class ll SBODG storage tanks. Level  ;

instrumentation provides operators the information necessary to ensure a minimum supply of 19,800 gallons in each Class I storage tank.

]

The minimum diesel fuel requirement per Class I storage tank (19,800 gallons) ensures  ;

that one EDG can operate continuously for approximately four days at rated capacity. j Seven days of continuous operation of both EDGs at rated capacity is ensured by augmenting the EDG fuel supply with the minimum quantity of fuel maintained in Class 11 storage tanks. The minimum fuel quantity in each EDG storage tank provides adequate time to plan and execute transfer of fuel from the SBO storage tanks.

Therefore, if either EDG storage tank contains less than 19,800 gallons of fuel prior to l a diesel start in response to a valid start signal, the respective EDG is declared  !

inoperable.

l l

When one EDG is inoperable, the quantity of fuel available to the operable EDG shall  !

consist of the volume of the fuelin the operable EDG storage tank and the SBODG  !

storage tanks and must be at least 36,800 gallons. The use of the SBODG storage )

tanks permits periodic draining of a EDG storage tank for inspection without declaring  !

both EDGs inoperable.

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b_TTACHMENT C - BECo Ltr. 2.99.029 AMENDED TECHNICAL SPECIFICATION PAGES TS Page No. 3/4.9-1 (Revised TS 3.9.A.3)

TS Page No. 3/4.9-3 (Revised TS 4.9.A.1.d)

TS Page No. B3/4.9-1(Revised Bases 3.9 for Auxiliary Electrical System) l Note: Amended UFSAR pages will be issued in accordance with 10 CFR 50.71(e) upon approval of the proposed License Amendment.

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LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.9 AUXlLIARY ELECTRICAL SYSTEM 4.9 AUXILIARY ELECTRICAL SYSTEM l Applicability: Applicability:

l Applies to the auxiliary electrical power Applies to the periodic testing requirements system. of the auxiliary electrical systems.

Obiective: Objective:

To assure an adequate supply of electrical Verify the operability of the auxiliary power for operation of those systems electrical system.

required for safety.

Specification:

Specification:

A. Auxiliary Electrical Eauipment A. Auxiliary Electrical Eauipment Surveillance The reactor shall not be made critical 1. Diesel Generators unless all of the following conditions are satisfied: a. Each diesel generator shall be manually started and loaded once l

1. At least one off-site transmission line each month to demonstrate  !

and the startup transformer are available operational readiness. The test shall i and capable of automatically supplying continue for at k ist a one hour l auxiliary power to the emergency buses. period at rated i 1.

2. An additional source of off-site power During the mon'...y generator test the consisting of one of the following: diesel generatu: starting air compressor shah be checked for

a. A transmission line and shutdown operation and its ability to recharge transformer capable of supplying air receivers. The operation of the power to the emergency 4160 volt diesel fuel oil transfer pumps shall be buses, demonstrated, and the diesel starting time to reach rated voltage and

b. The main transformer and unit frequency shall be logged.

auxiliary transformer available and capable of supplying power to the b. Once per operating cycle the emergency 4160 volt buses. condition under which the diesel generator is required will be simulate

3. Both diesel generators shall be and test conducted to demonstrate operable. Each diesel generator shall that it will start and accept the have a minimum of 36,800 gallons of diesel fuel on site. Of this volume, at emergency load within the specified least 19,800 gallons of fuel shall be time sequence. The results shall be stored in each EDG Class i fuel system. logged.

The balance of the 36,800 gallons /EDG shall be available in the Station Blackout diesel generator tanks.

PNPS 3/4.9-1 Amendment No.

LIMITING CONDITIONS FOR OPERATION SURVEILLANCE REQUIREMENTS 3.9 AUXILIARY ELECTRICAL SYSTEM 4.9 AUXILIARY ELECTRICAL SYSTEM A. Auxiliary Electrical Eauipment (Cont) A. Auxiliary Electrical Eauipment Surveillance

4. 4160 volt buses A5 and A6 are (Cont) energized and the associated 480 volt d. Once a month the quantity of diesel buses are energized. fuel available on-site shall be logged.

5. The station and switchyard 125 and 250 e. Once a month a sample of diesel fuel l volt batteries are operable. Each battery shall be checked for quality in shall have an operable battery charger, accordance with ASTM D4057-81 or l D4177-82. The quality shall be within

6. Emergency Bus Degraded Voltage the acceptable limits specified in Annunciation System as specified in Table 1 of ASTM D975-81 and Table 3.2.B.1 is operable. logged.

7 Specification: 2. Station and Switchyard Batteries  !

Two redundant RPS Electrical Protectio a. Every week the specific gravity, the Assemblies (EPAs) shall be operable at voltage and temperature of the pilot all times on both inservice power cell and overall battery voltage shall supplies. be measured and logged.

Action b. Every three months the measurements shall be made of

a. With one EPA on an inservice power voltage of each cell to nearest 0.1 supply inoperable, continued volt, specific gravity of each cell, and operation is permissible provided that temperature of every fifth cell. These the EPA is retumed to operable measurements shall be logged.

status or power is transferred to a source with two operable EPAs within c. Once each operating cycle, the 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. If this requirement cannot stated batteries shall be subjected to be met, trip the power source, a Service Discharge Test (load profile). The specific gravity and

b. With both RPS EPAs found to be voltage of each cell shall be inoperable on an inservice power determined after the discharge and supply, continued operation is logged.

permissible, provided at least one EPA is restored to operable status or d. Once every five years, the stated power is transferred to a source with batteries shall be subjected to a at least one operable EPA within 30 Performance Discharge Test minutes. If this requirement cannot (capacity). This test will be performe be met, trip the power source. in lieu of the Service Discharge Test NOTE: Only applicable if tripping the power I* 9 " * "" * ^' "

source would not result in a serem.

• PNPS 3/4.9-3 Amendment No.

l BASES:

3.9 AUXILIARY ELECTRICAL SYSTEM The general objective of this Specification is to assure an adequate source of electrical power to operate the auxiliaries during plant operation, to operate facilities to cool and lubricate the plant during shutdown, and to operate the engineered safeguards following an accident.

There are three sources of a-c electrical energy available; namely, the startup imnsformer, the diesel generators and the shutdown transformer. The d-c supply is required for switchgear and engineered safety feature systems. Specification 3.9.A states the required availability of a-c and d-c power; i.e., an active off-site a-c source, a back-up source of off-site a-c power and the maximum amount of on-site a-c and d-c sources.

The on-site diesel fuel supply system consists of two (2) 25,000 gallons Class i EDG storage tanks and two (2) 20,000 gallons Class il SBODG storage tanks. Levelinstrumentation provides operators the information necessary to ensure a minimum supply of 19,800 gallons in each Class i storage tank.

The minimum diesel fuel requirement per Class I storage tank (19,800 gallons) ensures that one EDG can operate continuously for approximately four days at rated capacity. Seven days of continuous operation of both EDGs at rated capacity is ensured by augmenting the EDG '

fuel supply with the minimum quantity of fuel maintained in Class 11 storage tanks. The minimum fuel quantity in each EDG storage tank provides adequate time to plan and execute i transfer of fuel from the SBO storage tanks. Therefore, if either EDG storage tank contains I less than 19,800 gallons of fuel prior to a diesel start in response to a valid start signal, the l respective EDG is declared inoperable. 1 When one EDG is inoperable, the quantity of fuel available to the operable EDG shall consist of the volume of the fuelin the operable EDG storage tank and the SBODG storage tanks and must be at least 36,800 gallons. The use of the SBODG storage tanks permits periodic draining of a EDG storage tank for inspection without declaring both EDGs inoperable Auxiliary power for PNPS is supplied from two sources; either the unit auxiliary transformer or the startup transformer. Both of these transformers are sized to carry 100% of the auxiliary load. If the startup transformer is lost, the unit can continue to operate since the unit auxiliary transformer is in service, the shutdown transformer is available, and both diesel generators are operational.

If the startup and shutdown transformers are both lost, the reactor power level must be reduced to a value whereby the unit could safely reject the load and continue to supply auxiliary electric power to the station.

In the normal mode of operation, the startup transformer is energized, two diesel generators and the shutdown transformer are operable. One diesel generator may be allowed out of service based on the availability of power from the startup transformer, the shutdown transformer and the fact that one diesel generator carries sufficient engineered safeguards equipment to cover all breaks. With the shutdown transformer and one diesel generator out of service, both 345kV supply lines must be available for the startup transformer.

Upon the loss of one on-site and one off-site power source, power would be available from the other immediate off-site power source and the one operable on-site diesel to carry sufficient engineered safeguards equipment to cover all breaks. In addition to these two power sources, removal of the Isolated Phase Bus flexible connectors would allow backfeed of power through the main transformer to the unit auxiliary transformer and provide power to carry the full station auxiliary load. The time required to perform this operation is comparable to the time the reactor could remain on RCIC operation before controlled depressurization need be initiated.

Amendment No.

B3/4.9-1