ML20058A396
| ML20058A396 | |
| Person / Time | |
|---|---|
| Site: | LaSalle  |
| Issue date: | 10/17/1990 |
| From: | Morgan W COMMONWEALTH EDISON CO. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| NUDOCS 9010260101 | |
| Download: ML20058A396 (9) | |
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Commonwealth Edison 1400 opus PI:ce Down:ta Grov3. Illinoim 00515 i
October 17,1990 U.S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555
Subject:
LaSalle County Station Unit 1 Division 2,125V Battery Replacement NBC.. Rocket 14o,_50 373 l
Reference:
(a):
M.H. Richter letter to T.E. Murley dated April 17,1989.
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Dear Sir:
l The attachments to this letter are provided in support of a proposed temporary
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battery supdy arrangement that is required to support the replacement of the LaSal e County Sta tion Unit Division 2,125 voit DC Batteries. The battery replacement modification is currently scheduled for the February 1991 Unit 2 Refueling Outage.
This temporary arrangement will not be implemented until your staff has reviewed and concurred with this submittal. The following attachments provide a discussion of the expeditious review of this su)mittal is appreciated. gement and a safety evaluati battery replacement, the pro wsed temporary arran Please direct any questions you may have to this office.
Very truly yours, k
h4 (Mi W. Morgan Nuclear Licensing Administrator Attachment cc: A.B. Davis Regional Administrator, Rlll Senior Resident ins tor - LSCS Robert Pulsifer - P ect Manager, NRR
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I ATTACHMENT 1 Unit 1 Temporary. B.attery_ Supply _Eorlbe.LSCS DMslon2Esttery_Beplacement LaSalle County Stations DC supply configuration currently is comprised of 3 125 voit batteries per unit, one for each division. Divisions 1 and 2 supply a variety of safety loads while Division 3 supplies only the HPCS System. In addition to the 3 batterles per unM, the Division 2 battery of the other unit is required to supply power for the following commons system: Control Room Ventilation, Standby Gas Treatment and Primary Containment Hydrogen Recombiners (Technical Specification 3.8.2.3).
LaSalle Station is currently replacing the Division 1 and 2 batteries in both units to accomodate additional station load requirements. In addition as a response to the NRC Station Blackout Rule, LaSalle Station committed (Reference a) to replace the Diviclon 2 batteries in each unit's next refueling outage. (Unit 1, February 1991, and UnN 2 January 1992). The Division 1 batteries were replaced Unit 1, November 1989 and Unit 2, April 1990.
The replacement of the Division 1 bctieries during the unit refueling outages, did not present problems with the operation of the other unit, in that the batteries were not needed for the other units operation and were not constrained by any Technical Specifications. Additionally, lessons learned were realized with no impact on the operating unit.
The re Macement of the Division 2 batteries requires that alternative DC power be suppliec while the battery is being replaced and tested. This action is required to avoid a shutdown of both units because of Technical Specification LCO requirements. Technical Specification 3/4.8.2.3 requires that the 125 volt Division 2 Battery of the shutdown unit be available within seven days. Since installation and testing will take longer than the LCO requirement, a temporary arrangement is being proposed that involves the use of the 250 volt battery for the unit which is having its battery re:) laced. The 250 voit battery will be center tapped and temporary cables w ll be used from the 250 valt battery to the 125 volt division 2
. bus. Eight 500MCM cables, four positive and four negative, approximately 200 feet long each will be used. (See the attached figure for the physical arrangement).
Access in the cable run location will be controlled to minimize any potential for f aults to occur in the cable which could damage the battery. This arrangement provides for the needs of the other unit and will allow the DC system to remain OPERABLE. This temporary arrangement will be limited to 6 weeks.
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2 in the performance of the 50.59 safety evalualton it was determined that this temporary configuration slightly increases the probablIity of a malfunction of the division 2 DC system for the other unit during a seismic event. This increased probability of a malfunction occurring is due to the fact that the cabling connecting the temporary battery and the DC buss will not be analyzed for a selsmic event.
Although LaSalle County is not in a seismically active area of the country (Illinois contingency and compensatory measures as described in the safety evaluation ),
(Attachment 2) will be implemented to provide reasonable assurance that the battery will be OPERABLE during the i mited replacement period.
The replacement of the Unit 1 Division 2 batteries is scheduled to begin in February 1991 and the Unit 2 replacement is scheduled for January 1992 (See for Installation Sequence).
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Page 1 of 4 Safety Evaluation
- 1. Is the probability of an occurrence or the consequences of an accident, or malfunction of equipment important to safety as previously evaluated in the Final Safety Analysis Report increased?
l res:
Non-Seismic cable - h e cable run from the 250 Volt center tapped battery to the 125 volt Division 2 bus will not be seismically supported. His configuration does not meet the seismic requiressats of ser'* 2 3.1.2 of the UFSAR.
Mitigattag circumstances o
Temporary Costiguration -
2 3 eenter tapped 250 Volt battery is class it and seisaleally qualified.
A asjority of the cable will rua on the floor and la cable trays.
Bis configuration is not likely to fail in a seismic event since the structure and equipment la the switchgear rocas are seismically tastalled.
m e connections to the celle and bus will act fail since they are similar to the estettag oomaeotions and will act add adottional weight.
All material used in this temp. alt. will be safety related.
S e doors will be blocked open or removed.
Se ran will be roped off and the stairwell closed to moraal traffte.
A servet11anoe of the emble will be done once per shift to taspect for oable damage.
1 Das Voltage will be read la the control toca once per shift.
Low voltage will alarm la the control room.
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Charger - me suisting Div. 2 battery abarger will be need as the preferred source of 125 Volt Siv. 2 DC power, he battery is needed la the event of charger failu :e or loss of off-site power. Se abarger is a permanent class 13 charger and has the capacity to handle the normal loads.
Bote that the charger does not meet the i
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i Page 2 of 4 i
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'PSAR requirement of having the current capacity to supply both the normal loads and the current to a fully discharged battery. Bowever, this requirement is not applicable since the battery will not be discharged.
If the battery becomes discharged the system will be l
declared inoperable and normal LCO applies.
o me reactor will be defueled.
Bence BCCS (or Division 1) is not required.
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o Redundancy - providing DC power to the defueled unit's 90, VC, and 30 i
systems will ensure redundancy with the running unit's equivalent i
eyetens. Se runniag unit's VG, VC, and 3G systens will be operable prior to starting this temporary alteration. No planned 000 of these,
systems will be scheduled during this temporary alteration.
Se redundancy between division 1 and division 2 of the defueled unit is not required since division 1 is not required.
Test l
Fire barrier eenpromised - gwo geek Spec fire doora will be block M opes or removed. One door is between the Division 1 switohgear room and a stairve11, at elevation 710, and the other door is between the Division 2 switobgear room and the same stairwell, at elevation 731.
See figure 1.
The configuration does not soot the fire protection requirements of sootton 9.5.1 of the Grana.
Lec8 is designed seek that a fire la one electrical divistem will not adversely effect the other division. staos fire barriers between divistans are temporarily removed, the somsequenoes of a fire, is tacreased. Bowever, the following measures will be taken to mitigated the consequences of a fire in one division affecting anothers o
geos Spee 3.7.6 will be followed.
o Establishing a continuous fire watch at both doors.
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Limittas the combustibles la the path created by the temporary rum.
Note that the oombustible load of the cable is lov.
o ' Me fact that the reactor will be defueled, hence 20C5 (Div 1) is not l.
required.
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Note 1 he affected doors a re 220 and 256 on unit 1, 254 and 269 on unit 3.
Se doors between units 1 & 2 are not required to be opea simultaneously due to this configuration.
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Page 3 of 4 2 !s the possibility for an accident, or malfunction of a different type than previously evaluated in the Final Safety Analysis Report created?
No8 L
he configuratica of the 125 Volt Division 2 battery system remains the saas, yallure of the temporary cables is identical to failure of L. i moraal cables.
The failure would have identical effects as tae single failure of the Divisice 1
2 battery as described la sootica 8.3.2.1.1 of the UySAa.
Electrical Separation -
One half of the 250 Volt battery which is located in the Division 1 switch gear, will power the Division 2 bus, however the battery will be completely electrically isolated from Divistoa 1 and will be treated as Divisten 2.
Cable separatica is asiatained by the temporary eable oomfiguration, physical Separattaa -
Although the Division 3 circuit will be located la the Divistoa 1 switehgear room, the propeeed emble will act rua near, (within three feet horisontal and five feet vertical), Divisten 1 elestrical i
equipaaet. Cable separation is asiatained by the temporary emble oomfiguratios. Me rua of cable la the divisten 1 switch gear room is
,m u m stalained, r arestaately 10 feet.
The only equipaast near the run is a netrud e MVAC deot. Bemee adverse latereotion la an event seek as a fire is alatained.
i b!v 3 reaalas sampletely physically separate frers the other units 419.1 and div. I systems.
Sinoe the temporary alteration does not violate electrical er physteal separation between two eleotrical divistems, no modes of failure are areated.
- 3. Is the snargin of safety as desned in the basis of any Todinial Rpacine= dan reduced?
Not o
Capacity - One half of the 280 9014 battery will be isolated and osaaeoted to the Div 3 mais bas,1(3)DCESB. the battery will supply no other leads. Me capeesty of the one half of the 250 Volt battery has been evaluated and found to l
be acceptable ' estag EIAS.*
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voltage - me battery terminal voltage will remata greater than or equal to 128 Veits om float abarge.
i The cable voltage drop sas evaluated using the carrent-BLMS loads and found to be' acceptable.
Se bas voltage j
will remata above 105 volts for the required four hours when suppling the actual emergency loada.
- Electrical loads monitoring system-data base for tracking electrical loads and inter connections.
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Electrolyte level, Float Voltage and Specific gravity requirements la the Tech Specs for the Div. 2 battery apply and will be adhered to.
o Tech Spee surveillance of the 125 Volt Div. 2 battery will be applied.
Temperature will be maintataed at or above 80'y.
o The above vill ensure that the battery will meet the Tech Spec basis and maintain the ability to supply emergency loads.
Other associated commitments o
If the Division 2 125 Volt Dc system including the temporary configuration is degraded and osa not perform its latended function, the system will be declared taoperable and the normal Lcos would apply.
Otherwise the system will be treated as operable, o
SWR Systems of the Nuclear Enginet. ring Departamat will detail the techatoal attributes of this temporary alteration la order to ensure that the configuration meets the intent of this safety evaluation, o
work will be done around the elook, (three shifts, seven days a week) to alaimise the length of time la this configurattom.
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. g Installation sequence Unit i l
o Declare 250 Volt battery inoperable.
o Cross-tie Units 1 & 2 125V Div. 2 (Start 3 day time clock),
o Lift 125 Volt Div. 2 battery main power leads under modification M01-1-88-003.
o Connect 1/2 of the 250 Volt battery, FPS-13 cells, to the 125 voit bus under the temporary alteration.
o Remove cross-tie under the temporary alteration (End time clock.
Div 2 is oonditionally operable).
o Replace the 125 Volt Div. 2 battery, except for landing the main foods, under modification M01-1-88-003.
o Install temporary feed to the temporary charger and connect to the new j
125V battery.
o Test & charge 125 Volt Div. 2 battery, under modification M01-1-80-003.
o Declare Div. 2 inoperable (Start 7 day time clock).
o cross-tie Units 1 & 2 125V Div. 2 (Start 3 day time clock).
o Remove the 250 Volt htttery center tap.
o Remove the temporary charger leads.
o Land the 125 volt Div. 2 battery ants feeds o
Retura 125 Volt Div. 2 battery se service, o
Replace and test Div. 2 charger under mod M01-1-88-002.
o Remove cross-tie Units 1 & 2 125V Div. 2 (End 3 day time clock).
o Retura 125 Volt DC Div. 2 to service.
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Replace, test and charge the 250 Volt battery under modification M01-1-88-001 o
Declare 250 Volt battery operable.
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Note that the 250 Volt battery may be replaced, tested and charged in parallel with replacement of the 125 Volt battery charger.
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