NRC-98-0002, Application for Amend to License NPF-43,revising SRs for Div II Battery Sys to Agree W/Design of New Battery Replacement

Application for Amend to License NPF-43,revising SRs for Div II Battery Sys to Agree W/Design of New Battery Replacement

ML20199G242
Person / Time
Site:	Fermi
Issue date:	01/28/1998
From:	Gipson D DETROIT EDISON CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
Shared Package
ML20199G245	List: ML20199H214 NRC-98-0002, Application for Amend to License NPF-43,revising SRs for Div II Battery Sys to Agree W/Design of New Battery Replacement
References
CON-NRC-98-0002, CON-NRC-98-2 NUDOCS 9802040244
Download: ML20199G242 (11)

Text

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'Irl 313 TM T.2"l I at 313 FM 415 2 Detroit Edison January 28,1998 NRC-98 0002 U. S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, D C 20555

References:

1) Ferm! 2 NRC Docket No. 50 341 NRC License No. NPF-43

2) ANSI /IEEE Standard 450-1972," Recommended Practice for Maintenance Testing and Replacement of Large Stationary Type Power Plant and Substation Lead Storage Batteries."

3) ANSI /IEEE Standard 4851983," Recommended Practice for Sizing Large Lead Storage Batteries for Generating Stations and Substations."

Subject:

Proposed Technical Specification Change (License Amendment) for the Division 11 130/260 VDC 11attery Reolacement Pursuant to 10CFR50.90, Detroit Edison Company hereby proposes to amend Operating License NPF-43 for the Fermi 2 plant by incorporating the enclosed changes into the Plant Technical Specifications (TS) 4.8.2.1.a.2,4.8.2.1.b, and 4.8.2.1.c.4. The proposed TS amendment revises surveillance requirements for the Division 11 battery system to agree with the design of the new battery replacement.

Detroit Edison plans to install the new battery during the sixth refueling outage (RF06), which is presently scheduled to begin in August 1998. Approval of this proposed license amendment is requested by July 31,1998 with implementation I.g 4

t prior to startup from RF0(i, to support the RF06 outage schedule.

Enclosure 1 provides a description and evaluation of the proposed changes.

Enclosure 2 provides an analysis of the significant hazards consideration assessment using the standards in 10CFR50.92.

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USNRC NRC 98-0002 Page 2 Endosure 3 provid, marked up pages of the existing Technical Specifications to show the proposed changes and a typed version of the affected Technical Specification pages with the proposed changes incorporated.

Detroit Edison has evaluated the proposed Technical Specification change against the criteria of 10CFR50.92 and determined that no significant hazards consideration is hivolved. The Fermi 2 Onsite Review Organization has reviewed and recommended approval of the proposed changes. The Nuclear Safety Review Group has also reviewed the proposed Technical Specification changes and concurs with the enclosed determinate.ns, in accordance with 10CFR50.91, Detroit Edison is providing a copy of this letter to the State of Michigan.

If you have any questions, please contact Mr. Norman K. Peterson at (734) 586-4258.

Sincerely, Q$V Enciosures cc: A. B.11each

13. L. Ilurgess G. A liarris A. J. Kugler Supervisor, Electric Operators, Michigan Putlic Service Commission

USNRC  !

NRC 98 0002 -

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i 1 IX)UGLAS R. GIPSON, do hereby affirm that the foregoing statements are based [

on facts and circumstances which are true and accurate to the best of my kno'wledge ' f, and belief.  :

- DOUGLAS R,'GIPSON Senior Vice President Nuclear Generation L

On this O day of _

%wAk1998 before me personally appeared Douglas R. Oipson, being first@uly sworf and says that he executed the foregoing as his free act and deed.

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F Enclosure i NRC 98-0002 Page1 l

l ENCLOSURE 1 FERMI 2 NRC DOCKET NO 50-341 OPERATING LICENSE NPF-43 REQUEST TO REVISE TdCllNICAL SPECIFICATIONS:

FOR Tile DIVISION 11130/260 VDC HATTERY REPLACEMENT DESCRIPTION AND EVALUATION OF TIIE PROPOSED CilANGES i.

F Enclosure i NRC-98-0002  ;

Page 2 BACKGROUND The proposed change involves revising Technical Specification (TS) Surveillance ,

Requirements 4.8.2.1.a.2,4.8.2.1.b, and 4.8.2.1.c.4 to agree with the replacement of the Division 11130/260 VDC station batteries.

The direct current (de) electrical power system provides de emergency power via the 130/260 VDC (Class IE and Balance of Plant) systems and the 24/48 VDC system.

The function of the Class 1E 130/260 VDC system is to provide de power to Class 1E de loads and for the control and switching of Class 1E systems. This power is provided through two sets (Divisions I and 11) of 130/260 VDC Category I station batteries with full capacity battery chargers. The Division 11260 volt battery (2PB) consists of two 130 volt batteries (2B 1 and 2D 2) connected in series.

The present Division 11 batteries have sufficient capacity to support the Fermi Design Basis Accident load profile; however, a trend in decreasing battery capacity has been seen during battery performance discharge testing. A recent battery performance test indicated increased signs of degradation in battery capacity of approximately seven percent for the 130 VDC battery 2B 1 and over two percent for the 130 VDC batt-ry 2B 2. It should be noted that even with this degradation, the existing batterio meet the present design requirements for assuring the batteries are capable of perfonning their functions and will be maintained above the crit:ria for battery replacement (as described in Reference 2, Section 6) until they are replaced.

The Division 11260 VDC battery is presently furnished by C&D Power Systems Inc.

This battery is a KC-17 type, lead calcium,1.215 specific gravity, and contains 120 cells (includes two 130 VDC batteries containing 60 cells each). This present battery will be replaced with a higher capacity battery furnished by C&D Technologies Inc.

The new battery will be a LCR 21 type, lead calcium,1.215 specific gravity, and contain i16 cells (includes two 130 VDC batteries containing 58 cells eac. ). The batteries are scheduled to be replaced during the sixth refueling outage (RF06).

The battery replacement will not . - ~ the existing battery system configuration.

The new Division 11260 VDC batter, * ' main located in the Auxiliary Building Division 11 Battery Room and will continue to supply de power through a set of 130 VDC station batteries. The battery replacement will change the battery capacity and number of cells per battery system.

- The replacement of the Division 11 130/260 VDC batteries provides bencfits for the de power sydem. The benefits include providing more capacity than the present

- batteries ana reducing the potential of tripping the Division 11 battery chargers on high vo5ge shutdown during equalizing charge.

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Encle. cure 1 NitC 98 0002 Page 3 EVAL,UATION Detroit Edison plans to replace the Division 11130/260 VDC station batteries. As stated above, the primary differences between the old and new batteries are the battery capacity and number of cells per battery system. The existing Division 11 battery system (120 cells)is being replaced with a physically larger and higher capacity battery consisting of 116 cells,

'Ihe 116 cell battery replacement meets ali the requirements of the existing 120 cell battery since the end of system discharge voltage of the new battery is the same as the original design for maintaining a minimum allowable battery system voltage of 210 VDC (includes two 130 VDC batteries each maintaining a minimum battery system voltage of 105 VDC). Th: 116 cell battery is physically larger as it requires larger size capacity cells to maintain the same minimum allowable battery system voltage.

T'..e new battery meets the 210 VDC minimum battery system voltage because the new battery end of discharge volts per cell (V/ cell) is greater than the present system.

The present 120 cell battery is designed for an end of discharge hattery voltage (minimum cell voltage) of 1.75 V/ cell.

1.75 V/ cell x 120 cell- 210 VDC (i.e.,105 VDC + 105 VDC)

Since the new 116 cell battery contains fewer cells, the minimum cell voltage must be held at a higher value to maintain the same minimum allowable battery system voltage of 210 VDC. The new 116 cell battery is designed for a minimum cell voltage of 1.81 V/ cell.

1.81 V/ cell x 116 cell = 210 VDC (i.e.,105 VDC + 105 VDC)

The new battery cell rating will have an increased capuity of over two times the existing battery cc:1 rating. Battery capacity is rated in ampere-hours, which detennines how long it will operate at a given discharge rate. The existing battery is designed to supply de power to all required loads for 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> (with a loss of ac power), without the minimum cell voltage dropping below 1.75 volts. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> rated capacity of the existing battery to 1.75 V/cellis 560 ampere-hours. The new battery is designed to supply de power under the same conditions as described but without the minimum cell voltage dropping below 1.81 volts. The 4 hour4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br /> rated capacity of the new battery to 1.81 V/ cell is 1200 ampere hours.

Since the end of system discharge voltage is the same, the new batteries will continue to have sullicient capacity to provide power to essential loads, in the event power to the chargers should be lost. The charge on the new batteries will be maintained by the existing battery chargers. The only change to the chargers will be a change to the

. Enclosure 1 NRC 98-0002 Page 4 setpoints to account for the difference in the number of cells per battery system. The setpoint changes are consistent with manufacturer's recommendations. Additionally, changing the battery system from 120 to 116 cells reduces the concern of the Division 11 battery chargers tripping on high voltage during equalize charging. Using fewer battery cella allows the setpoint band between the high voltage shutdown and equalizing voltage to be widened from approximately one volt to approximately three volts as shown in the table below:

Division 11 llattery Charcer Setnoint Chances Description Existing Setpoint New Setpoint liigh Voltage Shutdown 138.0 VDC (2.31 V/ cell) 138.5 VDC (2.39 V/ cell)

Equalize Voltage 137.5 VDC (2.29 V/ cell) 135.5 VDC (2.34 V/ cell) liigh Voltage Alarm 136.0 VDC (2.27 V/ cell) 134.0 VDC (2.31 V/ cell)

Float Voltage 133.0 VDC (2.22 V/ccll) 129.0 VDC (2.22 V/ccll)

Low Voltage' Alarm 128.5 VDC (2.14 V/ cell) 124.2 VDC (2.14 V/ cell)

• Discharged 11attery is 105 VDC (1.75 V/ cell for Division I and 1.81 V/ cell for Division 11)

The existing battery was sized with no margin and with an aging factor of 1 525 (10 year). A design margin of 10-15 percent and aging factor of 1.25 (20 year) is typically used in the design of a de system (Reference 3). The new battery system will have a design margin of approximately 10 percent and an aging factor of 1.25.

This TS amendment is proposing to change the 7 day,92 day, and 18 month surveillance requirements (TS Sections 4.8 '!.l.a.2,4.8.2.1.b, and 4.8.2.1.c.4) for the battery system terminal voltage on float charge, overcharge, and the minimum battery charger voltage respectively to correspond to the requirements of the replacement batterie.. The following evaluates each of the three changes:

1. Change to Surveillance Requirement 4.8.2.1.a.2:

TS Surveillance Requirement 4.8.2.1.a.2 requires that the Division I and 11 130 volt batteries and chargers be demonstrated OPERABLE at least once per 7 days by verifying that the," Total battery terminal voltage is greater than or equal to 130 volts on float charge". This surveillance requirement will be changed to state," Total battery terminal voltage is greater than or egaal to 130 volts for Division I and greater than or equal to 125.7 volts for Division 11 on float charge." Under normal operating conditions, the battery chargers produce a de output, which " float" charges the batteries. This new terminal (charging) voltage is acceptable because it is based

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. Enclosure 1 NRC 98-0002 page 5 5

on the same individual cell voltage u the existing 130 volt,1.215 specific gravity, lead calcium,60 ce!I system covered in ile present T.S.

Existing: (130 volts) / (60 cells) = 2.167 voits/ cell New: (2.167 volts / cell) x (58 cell) = 125.7 volts k

The basis for the battery terminal .". oat voltage ensures the effectiveness ef the charging system and the ability of the batteries to perfonn their intended function.

Float charge is the condition in which the charger is supplying a continuous charge required to overcome internal losses of a battery (or battery cell) and maintain the battery (or a battery cell) in a fully charged state.

2. Change to Surveillance Requirement 4.8.2.1.b:

TS Surveillance Requirement 4.8.2.1.b requires that the Division 1 and 11130 volt batteries and ch rgers be demonstrated OPERAllLE,"At least once per 92 days and within 7 days after a battery discharge with battery terrninal voltage below 105 volts, or battery overcharge with battery terminal voltage above 150 volts, by verifying that:" This surveillance requirement of verifying individual cells after a under or overvoltage condition will be changed to state,"At least once per 92 days and within 7 days after a battery discharge with be.ttery tenninal voltage less than 105 volts, or battery overcharge with battery terminal voltage greater than 150 volts for Divirion I and greater than 145 volts for Division 11, by verifying that:" This new battery terminal overvoltage for Division 11 is acceptable as it is based on the same individual cell voltage as the exisGng 130 volt,1.215 specific gravity, lead calcium, 60 cell system covered in the present T.S.

Existing: (ISO volts) / (60 cell) = 2.5 volts / cell New: (2.5 volts' cell) x (58 cell) = 145 volts This new overvoltage (or overcharge) value is acceptable as no immediate damage would be seen by the battery at this level. Overvoltage, if extreme and uncorrected for extended periods, will cause corrosion on the batteries' positive plates, increase ccll temperatures and increase water consumption. This voltage of 145 volts (or 2.5 volts / cell) is acceptable, as it is slightly greater then the maximum continuous recommended equalize chcrge voltage for the new and existing battery of 2.38 volts / cell.

3. Change to Surveillance Requirement 4.8.2.1.c.4:

TS St.rveillance Requirement 4.8.2.1.c.4 requires that the Division I and 11130-volt batteries and chargers be demonstrated OPERAllLE at least once per 18 months by verifying that,"The battery charger will supply at least 100 amperes at a minimum of 129 volts for at least 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />." This surveillance requirement will be changed to state,"The battery charger will supply at least 100 amperes at a minimum of 129 volts for Division I and at a minimum of 124.7 volts for Division 11 for at least 4

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e l Enclosure i NRC 98 0002 Page 6 l hours." This new battery charger terminal voltage for Division 11 is acceptable i tmcause it is based on the same individual cell voltage as the existing 170 volt 1.215 specific gravity, lead calcium,60 cell system covered in the present T.S.

Existing: (129 volts) / (60 cell) = 2.15 volts / cell Ncw: (2.1 $ volts / cell) x (58 cell) = 124.7 volts The minimum voltage c,f 124.7 volts (or 2.15 volts / cell), ensures that the battery can be maintained charged. The minimum voltage of 2.15 volts / cell is greater then the required continuous minimum cell float voltage of 2.13 volts / cell required by T.S. '

Table 4.8.2.1 1. Therefore, the surveillance requirement of the battery charger supplying this minimum voltage of 124.7 volts (or 2.15 volts / cell) at the chargers rated ampacity is acceptable.

SIGNIFICANT.II AZARDS CONSIDERATION in accordance with 10CFR50.92, Detroit Edison has made a detennination that the proposed amendment involves no significant hazards considerations. To make this determination, Detroit Edison must establish that operation in accordance with the proposed amendment would not: (1) involve a significant increase in the probability or consequences of an accident previously evaluated; or (2) create the possibility of a new or different kind of accident from any accident previously evaluated; or (3) involve a significant reduction in a margin of safety. The significant hazards consideration assessment is presented in Enclosure 2.

ENVIRONMENTAL IMPACT Detroit Edison has reviewed the proposed Technical Specification change against the criteria of 10CFR51.22 for environmental considerations. The proposed changes do not involve a significant hazards consideration, nor significantly change the types or significantly increase the amounts of effluents that may be released offsite, nor ,

significantly increase individual or cumulative occupational radiation exposures.

Ilased on the foregoing, Detroit Edison concludes that the proposed Technical Specifications do meet the criteria given in 10CFR51.22(c)(9) for a categorical exclusion from the requirements for an Environmental Impact Statement.

CONCLUSION Ilased on the evaluation above: 1) there is reasonable assurance that the health and safety of the public will not be endangered by operation in the proposed mannu, and -

2) such activities will be conducted m compliance with the Commission's regulations and proposed amendments will not be inimical to the common defense and security or to the health and safety of the public.

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. Enclosure 2 NRC 98-0002 Page1 ENCLOSURE 2 FERMI 2 NRC DOCKET 50-341 r

OPERATING LICENSE NPF-43 I REQUEST 'I O REVISE TECIINICAL SPECIFICATIONS:

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4 10CfR50.92 EVALUATION ll ASIS FOR $1GNIFICANT II AZARDS DETERMINATION _t The proposed Technical Specification changes described in Encl ~"

invohe a significant hazards consideration for the following r x

1. The changes do not involve a significant increa . the p. .eility or consequences of an accident previously evah c .

The proposed changes do not involve a change in the manner in which the plant is operated. TS Section 4.8.2.1 h being revised to reflect the new Division 11 battery cell / system characteristics and associated requireraents. The new battery y will have an increased capacity over the present battery, while maintaining the existing battey system voltage requirements. This is possible because the present and new battery specific gravity (1.215) and type (lead calcium) are the saine. Also, the end of battery system discharge voltage remains tb same as 210 VDC. The Division 11 batteries will continue to furnish power to redundant  !

essential loads ae required and as designed. The new surveillance requirement voltages are based on the same volts / cell criteria used for the existing batteries.

Furthennore, failure or malfunction of the station batteries does oot initiate any L, of the analyzed accideni4 previously evaluated in the UFSAR. The changes desc;ibed will therefore not involve an increase in the probability or y consequences of an a ccident previously evaluated.

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.. Enclosure 2 NRC-98 0002 Page 2 4

2. The changes do not create the possibility of a new or different kind of accident from any accident previously evaluated.

The new battery is Class 1E qualified equipment and is being maintained within the same overall design parameters as the existing battery That is, .he battery terminal voltage on Hoat voltage conditions (2.167 volt / cell), overvoltage conditions (2.5 volts / cell) and charger capability (2.15 volts / cell) are the same as the original design. Furthermore, the end of system discharge voltage of the battery system is maintained the same; therefore, there is no negative impact to plant loads supplied by the batteries. Failures of the batteries and chargers have been considered in both the existing and modified configurations. The proposed changes will not change perfonnance or reliability nor introduce any new or

• different failure modes or common mode failure and will therefore not create the possibility of a new or different kind of accident from any accident previously evaluated, c 3. The chan o.s do not involve a significant reduction in the margin of saf:ty.

The changes et to increase overall battery capacity from 560 ampere-hours to 1200 ampere-hours with the minimum battery discharge voltage remaining at 210 VDC (or 105 VDC per battery). The battery terrninal voltage on Hoat voltage ,

cc 3ditions (2.167 volt / cell), overvoltage conditions (2.5 K 211) and charger capability (2.15 volts / cell) are the same as the original desiga. The new surveillance requirement voltages are based on the same volts / cell criteria used for the existiig batteri:s. The batteriet ability to satis!, the design requirements

-- (battery duty cycle) of the de system will not be reduced from o iginal plant

' design and will therefore not have any negative impact to plant loads the battery supplies. The proposed changes therefore do not involve a reduction in the margin of safety.

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