ML18036A890
| ML18036A890 | |
| Person / Time | |
|---|---|
| Site: | Browns Ferry  |
| Issue date: | 10/09/1992 |
| From: | TENNESSEE VALLEY AUTHORITY |
| To: | |
| Shared Package | |
| ML18036A889 | List: |
| References | |
| NUDOCS 9210140280 | |
| Download: ML18036A890 (20) | |
Text
UNIT 1 EFFECTIVE PAGE LIST RENOVE 3.9/4.9-19 3.9/4.9-20 INSERT 3.9/4.9-19 3.9/4.9-20 9210140280 921009 PDR ADOCK 05000259
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3- '9 265KB The objective of this specification is to assure an adequate source of electrical power to operate facilities to cool the plant during shutdown and to operate the engineered safeguards following an accident.
There are three.sources of alternating, current.:electrical energy available,
- namely, the 161-kV transmission
- system,
.the 500-kV transmission
- system, and the diesel generators.
The unit station-service transformer B for unit 1 or the unit station-service transformer B for unit 2 provide noninterruptible sources of offsite power from the 500-kV transmission system to the units 1 and 2 shutdown boards.
Auxiliary power can also be supplied from the 161-kV transmission system through the common station-service transformers or through the-cooling-tower -transformers-by way of-the bus tie board.
The 4-kV bus tie board may remain out of, service indefinitely provided one of the required offsite power sources is not supplied from the 161-kV system through the bus tie board.
The minimum fuel oil requirement of 35,280 gallons for each diesel generator fuel tank assembly is sufficient for seven days of full load operation of each diesel and is conservatively based on availability of
~'
replenishment supply.
Each diesel generator has its own independent 7-day fuel oil storage tank assembly.
The degraded voltage sensing relays provide a start signal to the diesel generators in the event that a deteriorated voltage condition exists on a 4-kV shutdown board.
This starting signal is independent of the starting signal generated by the complete loss of voltage relays and will continue to function and start the diesel generators on complete loss of voltage should the loss of voltage relays become inoperable.
The 15-day inoperable time limit specified when one of the three phase-to-phase degraded voltage relays is inoperable is justified based on the two-out-of-three permissive logic scheme provided with these relays.
A 4-kV shutdown board is allowed to be out of operation for a brief period to allow for maintenance and testing, provided all remaining 4-kV shutdown boards and'associated diesel generators, CS,
- boards, and all emergency 480-V power boards are OPERABLE.
The 480-V diesel auxiliary board may be out of service for short periods for tests and maintenance.
There is a safety related 250-V dc unit battery located in each unit.
Each 250-V dc unit battery system consists of a battery, a battery
- charger, and a distribution panel.
There is also a backup charger which can be assigned to any one.of.the. three unit batteries.
The 250-V dc unit battery systems provide power for unit control functions, unit DC motor loads and alternate control power to the 4160 and 480-V ac shutdown boards.
The primary control power supplies to the 3A, 3C and 3D 4160-V ac shutdown boards and the Unit 3 480-V ac shutdown, boards are BFN Unit 1 3.9/4.9-19
I C s A
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(Cont'lso provided by unit batteries.
There are five safety related 250-V dc shutdown battery systems assigned as primary control power supplies to 4160-V dc shutdown boards A, B, C, D, and 3EB.
Each of these shutdown
.. battery systems has as 250-V dc-battery,.a charger, and a distribution panel.
A portable.spare charger can be.used to supply any one.-of the five shutdown battery systems.
Each 250-V dc shutdown board control power supply can receive power from its own battery, battery charger, or from a spare charger.
The chargers are powered from normal plant auxiliary power or from the standby diesel-driven generator system.
Zero resistance short circuits between the control power supply and the shutdown board are cleared by fuses located.in -the-respective-control-power-supply.
.Each power supply is located in the reactor building near the shutdown board it supplies.
Each battery is located in its own independently ventilated battery room.
The 250-V dc system is so arranged, and the batteries sized so that the loss of any one unit battery will not prevent the safe shutdown and cooldown of all three units in the event of the loss of offsite power and a design basis accident in any.,one unit.
Loss of control power to
~
any engineered safeguard control circuits is annunciated in the main control room of the unit affected.
The loss of one 250-V shutdown board battery affects normal control power only for the 4,160-V shutdown board which it supplies.
There are two 480-Volt ac RNOV boards that contain mg sets in their feeder lines.
These 480-Volt ac RNOV boards have an automatic transfer from their normal to alternate power source (480-Volt ac shutdown boards).
The mg sets act as electrical isolators to prevent a fault from propagating between electrical divisions due to an automatic transfer.
The 480-Volt ac RNOV boards involved provide motive power to valves associated with the LPCI mode of the RHR system.
Having an mg set out of service reduces the assurance that full RHR (LPCI) capacity will be available when required.
Since sufficient equipment is available to maintain the minimum complement required for RHR (LPCI) operation, a 7-day servicing period is justified.
Having two mg sets out of service can considerably reduce equipment availability; therefore, the affected unit shall be placed in Cold Shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The offsite power source requirements are based on the capacity of the respective lines.
The Trinity line is limited to supplying two operating units because of the load limitations of CSST's A and B.
The Athens line is limited to supplying one operating unit because of the load limitations of the Athens line.
The limiting conditions are intended to prevent the -161-kV system from supplying more than two units in the event of a single failure in the offsite power system.
BFN Unit 1 3.9/4.9-20
UNIT 2 EFFECTIVE PAGE LIST RENOVE 3.9/4.9-19 3.9/4.9-20 INSERT 3.9/4.9-19 3.9/4.9-20
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- 3. 9 BAKE The objective of this specification is to assure an adequate source of electrical power to operate facilities to cool the plant during shutdown and to operate the engineered safeguards following an accident.
There
'" are three sources of alternating current electrical energy"available,
- namely, the 161-kV transmission system,= the 500-kV.transmission
- system, and the diesel generators.
The unit station-service transformer B for unit 1 or the unit station-service transformer B for unit 2 provide noninterruptible sources of offsite power from the 500-kV transmission system to the units 1 and 2
shutdown boards.
Auxiliary power can also be supplied from the 161-kV transmission system through the common station-service transformers or through'he cooling tower transformers by-way-of-the-bus-tie-board.
The 4-kV bus tie board may remain out of service indefinitely provided one of the required offsite power sources is not supplied from the 161-kV system through the bus tie board.
The minimum fuel oil requirement of 35,280 gallons for each diesel generator fuel tank assembly is sufficient for seven days of full load operation of each diesel and is conservatively based on availability of a
" replenishment-supply.
Each diesel generator has its own independent 7-day fuel oil storage tank assembly.
The degraded voltage sensing relays provide a start signal to the diesel generators in the event that a deteriorated voltage condition exists on a 4-kV shutdown board.
This starting signal is independent of the starting signal generated by the complete loss of voltage relays and will continue to function and start the diesel generators on complete loss of voltage should the loss of voltage relays become inoperable.
The 15-day inoperable time limit specified when one of the three phase-to-phase degraded voltage relays is inoperable is justified based on the two-out-of-three permissive logic scheme provided with these relays.
A 4-kV shutdown board is allowed to be out of operation for a brief period to allow for maintenance and testing, provided all remaining 4-kV shutdown boards and associated diesel generators, CS,
- RHR, (LPCX and containment cooling) systems supplied by the remaining 4-kV shutdown
- boards, and all emergency 480-V power boards are OPERABLE.
The 480-V diesel auxiliary board may be out of service for short periods for tests and maintenance.
There is a safety related 250-V dc unit battery located in each unit.
Each 250-V dc unit battery system consists of a battery, a battery
- charger, and a distribution panel.
There is also a backup charger which can be assigned to any one of the three unit batteries.
The 250-V dc unit battery systems provide power for unit control functions, unit DC motor loads and alternate control power to the 4160 and 480-V ac shutdown boards.
The primary control power supplies to the 3A, 3C and 3D 4160-V ac shutdown boards and the Unit 3 480-V ac shutdown boards are also provided by unit batteries.
There are five safety related 250-V dc shutdown battery systems assigned as primary control power supplies to BFN Unit 2 3.9/4.9-19
~ a'
4160-V ac shutdown boards A, B, C, D, and 3EB.
Each of these shutdown battery systems has as 250-V dc battery, a charger, and a distribution panel.
A portable spare charger can be used to supply any one of the five shutdown battery systems.
Each 250-V dc shutdown board control power supply can receive power from its own battery, battery charger, or from a spare charger.
The chargers are powered from normal plant auxiliary power or from the standby diesel-driven generator system.
Zero resistance short circuits between the control power supply and the shutdown board are cleared by fuses located in the respective control power supply.
Each power supply is located in the reactor building near the shutdown board it supplies.
Each battery is located-in.its own independently-ventilated battery room.
The 250-V dc system is so arranged, and the batteries sized so that the loss of any one unit battery will not prevent the safe shutdown and cooldown of all three units in the event of the loss of offsite power and a design basis accident in any one unit.
Loss of control power to any engineered safeguard control circuits is annunciated in the main control room of the unit affected.
The loss of one 250-V shutdown board
-"'attery affects normal control power for the 480-V and 4,160-V shutdown boards which it supplies.
There are two 480-V ac RMOV boards that contain mg sets in their feeder lines.
These 480-V ac RHOV boards have an automatic transfer from their normal to alternate power source (480-V ac shutdown boards).
The mg sets act as electrical isolators to prevent a fault from propagating between electrical divisions due to an automatic transfer.
The 480-V ac RHOV boards involved provide motive power to valves associated with the LPCI mode of the RHR system.
Having an=mg set out of service reduces the assurance that full RHR (LPCI) capacity will be available when required.
Since sufficient equipment is available to maintain the minimum complement required for RHR (LPCI) operation, a 7-day servicing period is justified.
Having two mg sets out of service can considerably reduce equipment availability; therefore, the affected unit shall be placed in Cold Shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The offsite power source requirements are based on the capacity of the respective lines.
The Trinity line is limited to supplying two operating units because of the load limitations of CSST's A and B.
The Athens line is limited to supplying one operating unit because of the load limitations of the Athens line.
The limiting conditions are intended to prevent the 161-kV system from supplying more than two units in the event of a single failure in the offsite power system.
Specification 3.9.D provides the OPERABILITY requirements for the Unit 3 diesel generators when they serve as emergency power supplies to standby gas treatment train C and control room emergency ventilation train B
when they are being considered OPERABLE for. Unit 2 technical specifications.
The allowable out of service time of 30 days is commensurate with the importance of the affected systems when Unit 3 is in cold shutdown, the low probability of a LOCA/Loss of offsite power
~
and availability of onsite power to redundant trains.
BFN Unit 2 3.9/4.9-20
UNIT 3 EFFECTIVE PAGE LIST RENOVE 3.9/4.9-18 3.9/4.9-19 INSERT 3.9/4.9-18 3.9/4.9-19
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3 9
@SEE The objective of this specification is to assure an adequate source of electrical power to operate facilities to cool the unit during shutdown and to operate the engineered safeguards following an accident.
There are three sources of alternating current electrical energy available,
- namely, the 161-kV transmission
- system, the 500-kV transmission
- system, and the diesel generators.
The unit station-service transformer B for unit 3 provides a
noninterruptible source of offsite power from the 500-kV transmission system to the unit 3 shutdown boards.
Auxiliary power can also be supplied from the 161-kV transmission system through the common station-service transformers or through the cooling tower transformers by way, of the bus tie,board..
The,4-.kV bus tie.board,may, remain, out of service indefinitely provided one of the required offsite power sources is not supplied from the 161-kV system through the bus tie board.
The minimum fuel oil requirement of 35,280 gallons for each diesel generator fuel tank assembly is sufficient for seven days of full load operation of each diesel and is conservatively based on availability of a replenishment supply.
Each diesel generator has its own independent
,~7~day..fuel. oil storage tank assembly.
The degraded voltage sensing relays provide a start signal to the diesel generators in the event that a deteriorated voltage condition exists on a 4-kV shutdown board.
This starting signal is independent of the starting signal generated by the complete loss of voltage.relays and will continue to function and start the diesel generators on complete loss of voltage should the loss of voltage relays become inoperable.
The 15-day inoperable time limit specified when one of the three phase-to-phase degraded voltage relays is inoperable is justified based on the two-out-of-three permissive logic scheme provided with these relays.
A 4-kV shutdown board is allowed to be out of operation for a brief period to allow for maintenance and testing, provided all remaining 4-kV shutdown boards and associated diesel generators, CS,
- boards, and all emergency 480-V power boards are OPERABLE.
The 480-V diesel auxiliary board may be out of service for short periods for tests and maintenance.
There is a safety related 250-V dc unit battery located in each unit.
Each 250-V dc unit battery system consists of a battery, a battery
- charger, and a distribution panel.
There is also a backup charger which can be assigned to any one of the three unit batteries.
The 250-V dc unit battery systems provide powe'r for unit'ontrol functions, unit DC motor loads and alternate control power to the 4160 and 480-V ac shutdown boards.
The primary control power supplies to the 3A, 3C and BFN Unit 3 3.9/4.9-18
k
3D 4160-V ac shutdown boards and the Unit 3 480-V ac shutdown boards are also provided by unit batteries.
There are five safety related 250-V dc shutdown battery systems assigned as primary control power supplies to 4160-V ac shutdown boards A, B, C, D, and 3EB.
Each of these shutdown battery systems has as 250-V dc battery, a charger, and a distribution panel.
A portable spare charger can. be used to supply any one of the five shutdown battery systems.
The 250-V dc system is so arranged and the batteries sized so that the loss of any one unit battery will not prevent the safe shutdown and cooldown of all three units in the event of the loss of offsite power and a design basis accident in any one unit.
Loss of control power to any engineered-safeguard
.control circuits is annunciated in..the main control room of the unit affected.
There are two 480-V ac RMOV boards that contain mg sets in their feeder lines.
These 480-V ac RNOV boards have an automatic transfer from their normal to alternate power source (480-V ac shutdown boards).
The mg sets act as electrical isolators to prevent a fault from propagating between electrical divisions due to an automatic transfer.
The 480-V ac
~ RNOV boards involved provide motive power to valves associated with the LPCI mode of the RHR system.
Having an mg set out of service reduces the assurance that full RHR (LPCI) capacity will be available when required.
Since sufficient equipment is available to maintain the minimum complement required for RHR (LPCI) operation, a 7-day servicing period is justified.
Having two mg sets out of service can considerably reduce equipment availability; therefore, the affected unit shall be placed in Cold Shutdown within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.
The offsite power source requirements are.based on the capacity of the respective lines.
The Trinity line is limited to supplying two operating units because of the load limitations of CSST's A and B.
The Athens line is limited to supplying one operating unit because of the load limitations of the Athens line.
The limiting conditions are intended to prevent the 161-kV system from supplying more than two units in the event of a single failure in the offsite power system.
Specification 3.9.D provides the OPERABILITY requirements for the Unit 3 diesel generators when they serve as emergency power supplies to standby gas treatment train C and control room emergency ventilation train B
when they are being considered OPERABLE for Unit 2 technical specifications.
The allowable out of service time of 30 days is commensurate with the importance of the affected systems when Unit 3 is in cold shutdown, the low probability of a LOCA/Loss of offsite power and availability of onsite power to redundant trains.
BFN Unit 3 3.9/4.9-19
ENCLOSURE 2
REASON FOR CHANGE, DESCRIPTION AND JUSTIFICATION BROWNS FERRY NUCLEAR PLANT (BFN)
UNITS 1, 2 AND 3 (TVA BFN TS 325)
REASON FOR CHANGE:
The Bases -for-TS-3..9"refers
-to.-nonsafety, related 250-,V. dc systems and power supplies to nonsafety motor generator sets which were not part of the licensing bases of the plant and which do not form the bases for any Limiting Conditions for Operation.
References to the nonsafety related subsystems are being deleted, rather than changing the TSs to reflect planned modifications to the nonsafety related subsystems.
Also, because of unit interdependence, it is appropriate to discuss all safety related 250-V dc systems in the TSs bases for all units.
This change will also add the bases for Limiting Conditions for Operation for the Diesel Auxiliary Boards for Units 1 and 2.
DESCRIPTION OF THE PROPOSED CHANGE:
This change applies to Units 1, 2, and 3.
Existin TSs:
For Units 1 and 2 the Bases for section 3.9 states (sixth paragraph on page 3.9/4.9-19):
There are eight 250-V dc battery systems, each of which consists of a battery, battery charger, and
.distribution equipment.
Three of these systems provide power for unit control function, operative power for unit motor loads, and alternative drive power for a 115-V ac unit-preferred mg set.
One 250-V dc system provides power for common plant and transmission system control functions, drive power for a 115-V ac plant-preferred mg set, and emergency drive power for certain unit large motor loads.
The four remaining systems deliver control power for the 4,160-V shutdown boards.
For Unit 3 the Bases for section 3.9 states (sixth paragraph on page 3.9/4.9-18):
The 480-V diesel auxiliary board may be out of service for short periods for tests and maintenance.
There are five 250-V dc battery systems associated with Unit 3, each of which consists of a battery, battery charger, and distribution -equipment;.- -Three-of-these"systems provide power for unit control functions, operative power for unit motor loads, and alternative drive power for a 115-V ac unit preferred mg set.
One 250-V dc system provides power for common plant and transmission system control functions, drive power for a 115-V ac plant-preferred mg set, and emergency drive power for certain unit large motor loads.
The fifth battery system delivers control power to a 4-kV shutdown board.
Pro osed Chan e:
The proposed change would replace the above referenced paragraphs with the following:
The 480-V diesel auxiliary board may be out of service for short periods for tests and maintenance.
There is a safety related 250-V dc unit battery assigned to each unit,.
Each 250-V dc unit battery system consists of a
- battery, a battery charger, and a distribution panel.
There is also a backup charger which can be assigned to any one of the three unit batteries.
The 250-V dc unit battery systems provide power for unit control functions, unit DC motor loads and alternate control power to the 4160 and 480-V ac shutdown boards.
The primary control power supplies to the 3A, 3C, and 3D 4160-V ac shutdown boards and the Unit 3 480-V ac shutdown boards are also provided by unit batteries.
There are five safety related 250-V dc shutdown battery systems as-signed as primary control power supplies to 4160-V ac shutdown boards A, B, C,
D, and 3EB.
Each of these shutdown battery systems has a 250-V dc battery, a charger, and a
distribution panel.
A portable spare charger can be used to supply any one of the five shutdown battery systems.
Existin TSs:
The Bases for section 3.9 states for Units 1 and 2 on pages 3.9/4.9-20 and for Unit 3 on page 3.9/4.9-19:
The station battery supplies loads that are not essential for safe shutdown and cooldown of the nuclear system.
This battery was not considered in the: accident-load--calculations.."-
Pro osed Chan e:
The above statements would be deleted.
JUSTIFICATION FOR THE CHANGES:
These changes will remove references to nonsafety related 250-V dc subsystems and motor generator sets which were not the bases for any Limiting Conditions for Operations.
Discussion of the Unit 250-V dc systems and the shutdown Board 250-V dc control power systems together for all units recognizes the interdependence of the units and clarifies the Bases.
The existing TSs Bases for all units discuss unit battery systems 1, 2, and 3, and nonsafety related plant battery system 4.
Reference to the nonsafety related battery system 4 is being deleted.
For Units 1 and 2, only shutdown batteries A, B, C,
and D are discussed in the Bases.
For Unit 3, only shutdown battery 3EB is discussed in the Bases.
The proposed change to the Bases will discuss shutdown batteries A, B, C,
D and 3EB in the TSs for Units 1, 2,
and 3
since these batteries have functions associated with all units.
Adding Bases information for the 480-V ac Diesel Auxiliary boards to Units 1 and 2 clarifies the associated TS requirements.
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