ML20210B870

Proposed Changes to Tech Spec Sections 4.2.3 & 2.6, Describing Replacement & Mod of Noninterruptible Bus 1C

ML20210B870
Person / Time
Site:	La Crosse File:Dairyland Power Cooperative icon.png
Issue date:	02/04/1986
From:	DAIRYLAND POWER COOPERATIVE
To:
Shared Package
ML20210B867	List: ML20210B861 ML20210B870
References
NUDOCS 8602100121
Download: ML20210B870 (9)

Text

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I i EXISTING TECHNICAll SPECIFICATION 2.'6.1.2 The unit auxiliary transformer and the reserve auxiliary transformer outputs shall be divided between two independent 2400 volt busses, and each component of duplicated equipment shall be k supplied by a different bus. The duplicated equipment shall include the primary system forced circulation pumps, the reactor feedwater

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pumps, the condensatc pumps, and the condenser circulating water pumps. Each 2400 volt bus shall also supply power to a 480. volt ,

bus. If the supply to either 480 volt bus fails, a connection may be manually made from the other 480 volt bus. Duplicate equipment shall also be supplied by the 480 volt buses.

2.6.1.3 Each 480 volt bus shall normally supply power to its associated essential bus. The'480 volt Bus lA shall supply the 480 volt Essential Switchgear Bus lA. The 480 volt Essential Switchgear Bus lA shall supply high pressure core spray pump 1A and Turbine Building Motor Control Center lA which shall supply the Turbine Building 120 volt Bus which in turn supplies the Turbine Building  !'

120 volt Regulated Bus. Powerfor'theReactorFlantBatteryChargerf' shall be supplied by Turbine Building Motor Control Center lA. g The Reactor Plant Battery Charger shall carry the load of and cha,rge t '

the batteries on the Reactor Plant 125 volt DC Bus.

The Reactor Plant 125 volt DC Bus shall normally supply power for Static Inverter lA which is capable of supplying power to essential reactor instrumentation and control circuits connected to 120 volt AC Non-Interruptible Bu's lA. In case of Static Inverter lA trouble, -

( an electro-=echanical transfer switch located in Static Inverter lA shall autematically transfer to its alternate power supply which is Turbine Building 120 volt Regulated Bus.

The reserve tie breaker between the Turbine Building 120 volt Regulated Bus and the 120 volt AC Non-Interruptible Bus 1B will be~administra-tively controlled to prevent its cicsure when the Turbine Building 120 vcit Regulated Bus is being'used as the alternate power supply to the 120 volt AC Non-Interruptible Bus lA.

The Reactor Plant 125 volt DC Bus shall supply power to the retary inverter which is capable of supplying backup power to essential reactor instrumentation and control circuits connected to 120 volt AC Non-Interruptible Bus 1B. The Reactor Plant 125 volt DC Bus is capable of providing power to the Generator Plant 125 volt DC Bus, Mfj w hich supplies power to reactor water level channel 3 through bp Static Inverter 1C.

0 The 430 vcit Eus 1B also supplies pcwer to the 480 voit Turbine Building Mctor Centrcl Center ID. Turbine Building Motor Control Cer.ter 10 is the ncrmal supply fer the Generator Plant 125 volt DC

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Bus through the Generator Plant' Battery Charger.

8602100121Og0009 ADOCK O PDR PDR

\ P Amendment No. p( t i-

PROPOSED 2.6.1.2 The unit auxiliary transformer and the reserve auxiliary transformer outputs shall be divided between two independent 2400 volt buses, and each component of duplicated equipment shall be supplied by.a different bus. The duplicated equipment shall include the primary system forced circulation pumps, the reactor feedwater pumps, the condensate pumps, and the condenser circulating water pumps. Each 2400 volt bus shall also supply power to a 480 volt bus. If the supply to either 480 volt bus fails, a connection may be manually made from the other 480 volt bus. Duplicate equipment shall also be supplied by the 480 volt buses.

2.6.1.3 Each 480 volt bus shall normally supply power to its associated essential bus. The 480 volt bus lA shall supply the 480 volt Essential Switchgear Bus lA. The 480 volt Essential Switchgear Bus IA shall supply high pressure core spray pump 1A and Turbine Building Motor Control Center lA which shall supply the Turbine Building 120 Volt Bus which in turn supplies the Turbine Building 120 Volt Regulated Bus. Power for the Reactor Plant Battery. Charger shall be supplied by Turbine Building Motor Control Center l A .' The Reactor Plant Battery Charger shall carry the load of and charge the batteries on the Reactor Plant 125 Volt DC bus.

The Reactor Plant 125 Volt DC bus shall normally supply power for Static Inverter lA which is capable of supplying power to essential reactor instrumentation and control circuits connected to 120 Volt AC Non-Interruptible Bus lA. In case of Static Inverter IA trouble, un electro-mechanical transfer switch located in Static Inverter lA shall automatically transfer to its alternate power supply which is Turbine Building 120 Volt Regulated Bus.

The reserve tie breaker between the Turbine Building 120 Volt Regulated Bus and the 120 Volt AC Non-Interruptible Bus IB will be administratively controlled to prevent its closure when the Turbine Building 120 Volt Regulated Bus is being used as the alternate power supply to the 120 Volt AC Non-Interruptible Bus lA.

The Reactor Plant 125 Volt DC bus shall supply power to the rotary inverter which is capable of supplying backup power to essential reactor instrumentation and control circuits connected to 120 Volt AC Non-Interruptible Bus 1B. The Reactor Plant 125 Volt DC Bus is capable of providing power to the Generator Plant 125 Volt DC Bus.

l The 480 Volt Bus IB also supplies power to the 480 Volt Turbine Building Motor Control Center ID. Turbine Building Motor Control Center ID is the normal supply for the Generator Plant 125 Volt DC Bus through the Generator Plant Battery Charger.

PC4-13 Amendment No.

L EXISTINGTECllNIdALSPECIFICATION I i t 1 The Generator Plant Battery Charger shall carry the load of and c

charge the batteries on the Generator Plant 125 volt DC Bus, '

i The Generator Plant 125 volt DC Bus shall normally su7 ply power to l a Generator t'lant 12d volt DC distribution panel whic1 supplies I power to reactor water level channel 3 through Static Inverter IC,

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The Diesel Building 480 volt Essential Switchgear Bus 1B shall supply gv high pressure core spray pump 1B, seal injection pump 1B, Reacter Building Motor Control Center lA and Diesel Building 480 volt Motor Control Center. Power for the Diesel Building Battery Charger.shall be supplied by the Diesel Building 480 volt Motor Control Center.

The Diesel Building Battery Charger shall carry the load of and charge the batteries on the Diesel Building Standby 125 volt DC Distribution Bus.

The Diesel Building Standby 125 volt DC Distribution Bus shall be the normal power supply for Static Inverter 1B which is capable of supplying power to essential reacter instrumentation and control circuits connected to 120 volt AC Mon-Interruptible Bus 1B.

The static switch of Static Inverter 1B shall be capable of supplying power from Static Inverter 1B or its reserve transformer to essential reactor instrumentation andIncontrol circuits connected to 120 volt AC case of Static Inverter 1B trouble, the Non-Interruptible Bus 1B.

static switch shall automatically transfer from the output of Static Inverter 1B to the output of its reserve transformer which is supplied

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by the Diesel Building 480 volt T!otor Control Center.

2.7 REACTOR CORE AND VESSEL INTERNALS 2.7.1 Vessel Internals and Core Structure .

2.7.1.1 The vessel internals shallinclude a thermal shield, c core support skirt, a plenun separator plate, a bottom grid assembly, internal steam separators, a thermal shock shield, a baffle plate structure with a peripheral lip, a steam dryer with support struacure, emergency core spray tube bundle structure ccmbined with fuel hol'd-down mechanism, and the reactor core structure.

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4 Amendment flo. p', t i 4

PROPOSED

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The Generator Plant Battery Charger shall carry the load of and charge the batteries on the Generator Plant 125 Volt DC Bus.

The Generator Plant 125 Volt DC Bus shall normally supply power to a Genere. tor Plant 125 Volt DC distribution panel which supplies power to essential reactor instrumentation and control circuits connected to 120 Volt AC Non-Interruptible Bus IC.

The static switch of the Static Inverter 1C shall be capable of supplying power for Static Inverter Switch IC or its reserve 120 Volt AC power source.

In case of Static Inverter 1C trouble, the static switch shall automatically transfer from the output o.f Static Inverter IC to .the reserve transformer which is supplied from Turbine Building Motor Control Center lA.

The Diesel Building 480 Volt Essential Switchgear Bus IB shall' supply high pressure core spray pump IB, seal injection pump 1B, Reactor Building Motor Control Center lA and Diesel Building 480 Volt Motor Control Center. Power for .the Diesel Building Battery Charger shall be supplied by the Diesel Building 480 Volt Motor Control Center. The Diesel Building Battery Charger shall carry the load of an charge the batteries on the Diesel Building Standby 125 Volt DC Distribution Bus.

The Diesel Building Standby 125 Volt DC Distribution Bus shall be the normal power supply for Static Inverter 1B which is capable of supplying power to essential reactor instrumentation and control circuits connected to 120 Volt AC Non-Interruptible Bus 1B.

The static switch of Static Inverter IB shall be capable .of supplying power from Static Inverter 1B or its reserve transformer to essential reactor instrumentation and control circuits connected to 120 Volt AC Non-Interruptible Bus IB. .In case of Static Inverter IB trouble, the static switch shall automatically transfer from the output of Static Inverter IB to the output of its reserve transformer which is supplied by the Diesel Building 480 Volt Motor Control Center.

2.7 REACTOR CORE AND VESSEL INTERNALS 2.7.1 Vessel Internals and Core Structure 2.7.1.1 The vessel internals shall include a thermal shield, a core support skirt, a plenum separator' plate, a bottom grid assembly, internal steam separators, a thermal shock shield, a baffle plate structure with a peripheral lip, a steam dryer with support structure, emergency core spray tube bundle structure combined with fuel hold-down mechanism, and the reactor core structure.

- 13a -

PC4-13 Amendment No.

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EXISTING TECHNICAL SPECIFICATION ELECTRICAL POWER SYSTEMS

( 4.2.3.2 ONSITE POWER DISTRIBUTION SYSTEMS A.C. DISTRIBU* ION - OPERATING LIMITING CONDITION FOR OPERATION ~

4.2.3.2.1 The following A.C. electrical buses shall be OPERABLE '

and energized from sources of power other than the diesel gener-ators with tie breakers open between re'dundant, buses;, '

a. 480-Volt A.C. Essential Switchgear Bus lA.

b. 480-Volt A.C. Diesel Building Essential Switchgear Bus 1B.

120-Volt A.C. Non-Interruptible Bus lA.

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d. 120-Volt"A.C. Non-Interruptible Bus'1B.

e. 120-Volt A.C. Turbine Building Regulated Bus, h f. 120-Volt A.C. 1 KVA Static Inverter from Generator Plant _

lz5-Volt D.C. Bus. - -

APPLICABILITY: OPERATIONAL CONDITIONS 1, 2 and 3

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ACTION:

a. With one of the above required A.C. dis'tribution system buses inoperable, restore the inoperable bus to OPERABLE status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at least 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 />.and in COLD SHUTOOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />,

b. With two or more of the above required A.C. distribution system buses inoperable,. restore.at least all except onet of the inoperable buses to OPERABLE status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least 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 /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Restore all of the above required A.C. distribution system buses to OPERABLE status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> from the time of initial loss or be in at least 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 /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

SURVEILLANCE REQUIREMENTS 5.2.11.1 The above required A.C. distribution system buses shall be determined OPERABLE at least once per 7 days by verifying correct breaker alignments and indicated power availability.

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- 32m -

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s Nx Amendment No. )i, 3 4 )

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PROPOSED

~ ELECTRICAL POWER SYSTEMS 4.2.3.2 ONSITE POWER DISTRIBUTION SYSTEMS A.C. DISTRIBUTION - OPERATING LIMITING CONDITION FOR OPERATION 4.2.3.2.1 The following A.C. electrical buses shall be OPERABLE and energized from sources of power other than the diesel generators with tie breakers open between redundant buses:

a. 480-Volt A.C. Essential Switchgear Bus IA.

b. 480-Volt A.C. Diesel Building Essential Switchgear Bus IB.

c. 120-Volt A.C. Non-Interruptible Bus lA.

d. 120-Volt A.C. Non-Interruptible Bus 1B.

e. 120-volt A.C. Turbine Building Regulated Bus.

f. 120-Volt A.C. Non-Interruptible Bus IC.

APPLICABILITY: OPERATIONAL CONDITIONS 1, 2 and 3 ACTION:

a. With one of the above required A.C. distribution system buses inoperable, restore the inoperable bus to OPERABLE status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> or be in at least 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 /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />,

b. With two or more of the above required A.C. distribution system buses inoperable, restore at least all except one of the inoperable buses to OPERABLE status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least 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 /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Restore all of the above required A.C.

distribution system buses to OPERABLE status within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> from the time of initial loss or be in at least 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 /> and in COLD SHUTDOWN within the following 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

SURVEILLANCE REQUIREMENTS

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5.2.11.1 The above required A.C. distribution system buses shall be determined OPERABLE at least once per 7 days by verifying correct breaker alignments and indicated power availability.

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PC4-13 Amendment No.

Enclosure #2 License No. DPR-45 Docket No. 50-409 Supporting Information and No Significant Hanania Conditions Analysis The proposed amendment of pages 13, 13a, and 32m of the La Crosse Boiling Water Reactor Technical Specifications is requested to increase the capability of one of three 120 VAC Non-Interruptible Instrument and Control Busses and add an alternate power source via the IC static transfer switch.

1. The proposed amendment in acconiance with the operation of the La Crosse Boiling Water Reactor vill not involve a significant increase in the probability qf consequences qf an accident previously evaluate 1.

The upgrading of the IC Inverter will not change or increase the probability or consequences of an accident previously evaluated. The new static inverter will add a static transfer switch which the existing static inverter does not have. The static switch will provide an alternate source to the IC Non-Interruptible Bus in the event the static inverter malfunctions.

Current design of the IC Non-Interruptible Bus would result in a reactor scram if the IC Static Inverter failed. The new design would minimize this challenge to the reactor protection system.

2. The proposed amendment in accordance with the operation of the La Crosse Boiling Water Reactor vill not create the possibility qf a neu or different kind of accident from any aoaident previously evaluated.

The replacement of the IC Static Inverter with a larger capacity unit and static transfer switch will not create a new or different kind of accident from any accident previously evaluated. The new static inverter is instrumented and alarm monitored more extensively than the existng unit.

With the addition of the IC static transfer switch, the existing risk of a loss of the IC Non-Interruptible Bus due to a IC Inverter malfunction will be greatly minimized.

3. The proposed amendment in acconlance uith the opdeltion of the La Crosse Boiling Vater Reactor uiLL nt a ino'olve a significant reduction in the margin pf safety.

As previously stated, the upgrade of the IC Non-Interruptible Bus will improve the operational expectations with the addition of an alternate source via the IC Static transfer switch. The proposed amendment will not involve a significant reduction in the margin of safety, in fact it will increase the margin of safety by increasing the reliability of a vital power supply.

As. determined by the analysis above, this proposed amendment has no significant hazards consideration.

WPl.4.7

Enclosure #3 The La Crosse Boiling Water Reactor was originally designed with one instrument bus fed by a 10 KW rotary inverter set. The rotary inverter was replaced in 1976 with a 15 KVA static inverter manuf actured by Solidstate Controls, model number SV12150/TSNB/TSMB. The normal supply to this inverter is the IB Diesel Generator (D/G) Building 125 VDC stationary battery and the static transfer switch alternate feed from the IB D/G Building 480V MCC. This inverter was designated IB since it was located in the new 1B Diesel Generator Building which also was built in 1976 to house a new redundant emergency diesel generator, essential switchgear and 125 VDC stationary battery bank.

Further concerns on single failure and post-accident monitoring led to the addition of a second inverter the same year. This 1 KVA inverter (IA) with an electro-machanical transfer switch is normally supplied by the Reactor Plant 125 VDC Battery Bank with its alternate source supplied from the 120 VAC Turbine Building Regulated Bus. A third reactor water level transmitter was also added in 1976 to provide redundancy and single failure protection against a common mode sensing line piping failure. This instrumentation loop was provided a single separate instrument inverter. The IC 1 KVA instrument inverter was manufactured by Advanced Conversion Devices Co. The inverter, model A66-1, is supplied 125 VDC input from the Generator Plant 125 VDC Stationary Battery Bank and has no alternate source. The reactor protection system uses a one-out-of-three trip logic for reactor water level. In the event of an undervoltage or loss of power of the IC inverter, the reactor will scram. Without a static transfer switch and alternate source, the IC 120 VAC instrument bus will be de-energized on loss of power or suf fer an undervoltage condition on a partial loss of the inverter. Currently, an auxiliary undervoltage relay monitors, the AC output of the inverter and is annunciated in the Control Room.

DPC has chosen a 5 KVA Solidstate Control Inverter, model number SCl2050, for several reasons. Due to many backfits for Post-THI actions, the Systematic Evaluation Program, Appendix R reviews, ATWS modification and general plant improvements, a reliable and larger power source is required to handle the additional demand. The capacity of the 1A inverter is fully utilized. The majority of the plant instrumentation is powered from IB inverter so any further separation of power supplies must be added to the IC inverter. In its current configuration with no alternate source, DPC could not increase the loading of the IC Inverter without compromising good engineering judgement. To properly modify the third instrument bus and prepare for future additions and modifications, a new and larger 5 KVA Inverter was selected. This upgrade is being made in conjunction with the replacement and increased capacity of the Generator Plant 125 VDC Stationary Battery Bank. The normal 125 VDC supply to the IC Inverter will continue to be the Generator Plant Battery but a static transfer switch will be added to provide an alternate source of 120 VAC power from Turbine Building Motor Control Center IA. This motor control center is supplied emergency power from the 1 A Emergency Diesel Generator. The IC Inverter is provided with alarms to indicate abnormal conditions such as loss of DC input, low DC voltage, manual bypass switch position, loss of alternate source, low AC output, and static switch transfer. These alarms will be annunciated in the Control Room on a common annunciator window labeled IC Inverter Trouble.

WPl.4.7 The IC instrument and control' bus will have an alternate source of power and a manual bypass switch that it previously lacked. The reliability of the IC Non-Interruptible bus will be increased and the possibility of challenging the reactor protection system on a total loss of the IC bus will be minimized by the addition of the alternate power source by using a static transfer switch.

WPl.4.7 t.