ML14268A353

Indian Point, Unit 2 - Proposed License Amendment Re an Exigent Change to Technical Specification 3.8.6, Station Battery Surveillance

ML14268A353
Person / Time
Site:	Indian Point
Issue date:	09/15/2014
From:	Ventosa J A Entergy Nuclear Northeast
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML14268A362	List: ML14268A353 ML14268A354 ML14268A355 ML14268A356 NL-14-122, Calculation FEX-00204, Rev. 1, Station Battery 22 System Calculation, Part 2 of 2 NL-14-122, Indian Point, Unit 2 - Calculation FEX-00204, Rev. 1, Station Battery 22 System Calculation, Part 1 of 2 NL-14-122, Indian Point, Unit 2 - Calculation IP-CALC-14-00028, Rev. 0, Station Battery 22 System Calculation - Analysis Variation with an Battery Aged to 80% Capaciy, Part 1 of 2 NL-14-122, Indian Point, Unit 2 - Calculation IP-CALC-14-00028, Rev. 0, Station Battery 22 System Calculation - Analysis Variation with an Battery Aged to 80% Capaciy, Part 2 of 2 NL-14-122, Indian Point, Unit 2 - Proposed License Amendment Re an Exigent Change to Technical Specification 3.8.6, Station Battery Surveillance
References
NL-14-122
Download: ML14268A353 (14)

Text

'§ EntergyEntergy Nuclear NortheastIndian Point Energy Center450 Broadway, GSBP.O. Box 249Buchanan, NY 10511-0249Tel 914 254 6700John A VentosaSite Vice PresidentSeptember 15, 2014NL-14-122U.S. Nuclear Regulatory CommissionATTN: Document Control Desk11545 Rockville Pike, TWFN-2 F1Rockville, MD 20852-2738

SUBJECT:

Proposed License Amendment Regarding An Exigent Change to TechnicalSpecification 3.8.6 Station Battery SurveillanceIndian Point Unit Number 2Docket No. 50-247License No. DPR-26

Dear Sir or Madam:

Pursuant to 10 CFR 50.90, Entergy Nuclear Operations, Inc, (Entergy) hereby requests a LicenseAmendment to Operating License DPR-26, Docket No. 50-247 for Indian Point Nuclear GeneratingUnit No. 2 (IP2). This exigent change is requested to revise the acceptance criteria for theSurveillance Requirement (SR) 3.8.6.6 for the 22 Battery. The 22 Battery met the SR 3.8.6.6during its performance on March 7, 2014. However, questions were raised during a recent PI&RSample Inspection about the continued operability of the Battery until the next surveillance test tobe performed by March 7, 2015. If the 22 Battery no longer meets the SR 3.8.6.6, then SR 3.0.1requires the battery to be declared inoperable even though it complies with applicable IEEErequirements until the next scheduled surveillance. The questions are based on a concern that the22 Battery will degrade and no longer meet SR 3.8.6.6 before the next scheduled test andtherefore must be demonstrated to meet the criteria to ensure strict TS compliance. The testcannot be done in Modes 1, 2, 3 or 4 and if the SR no longer meets SR 3.8.6.6, then SR 3.0.1requires the battery to be declared inoperable. Foreseeing that compliance with the SR is inquestion and there would be a need to revise the surveillance acceptance criteria or shut down theplant prior to the next scheduled surveillance could not reasonably have been foreseen oranticipated.An evaluation performed by Entergy has concluded that the SR will be met until September 25,2014. Therefore, Entergy requests approval of the proposed amendment on an exigent basis bySeptember 24, 2014 in order to resolve this issue. Entergy believes this request meets the criteriaof 10 CFR 50.91(a)(6) where the proposed change involves no significant hazards considerationsand that time does not permit the Commission to publish a Federal Register notice allowing 30days for prior public comment.

NL-14-122Docket No. 50-247Page 2 of 2Entergy has evaluated the proposed change in accordance with 10 CFR 50.91 (a)(5) using thecriteria of 10 CFR 50.92 (c) and has determined that this proposed change involves no significanthazards considerations. Attachment 1 includes this evaluation and describes the circumstancessurrounding this request, including how this request satisfies the exigent change criteria, and thatthe situation could not have been avoided. The proposed Technical Specification and, forinformation, the planned Bases changes are provided in Attachments 2 and 3, respectively. Acopy of this application and the associated attachments are being submitted to the designated NewYork State official in accordance with 10 CFR 50.91.There are no new commitments being made in this submittal. If you have any questions or requireadditional information, please contact Mr. Robert Walpole, Manager, Regulatory Affairs at (914)254-6710.1 dgc.Ipe under penalty of perjury that the foregoing is true and correct. Executed on September,2014.Sincerely,Attachments: 1. Analysis of Proposed Exigent Technical Specification ChangeRegarding Change to Surveillance Requirement 3.8.6.62. Markup of Technical Specification Change to Surveillance Requirement3.8.6.63. Markup of TS Bases 3.8.4 and 3.8.6 Changes Associated withSurveillance Requirement 3.8.6.6 Revision

Enclosure:

Calculation I P-CALC-14-00028 -Station Battery 22 System Calculation -Analysis Variation with an Battery Aged to 80% Capacitycc: Mr. Douglas Pickett, Senior Project Manager, NRC NRR DORLMr. William M. Dean, Regional Administrator, NRC Region 1NRC Resident Inspectors OfficeMr. John B. Rhodes, President and CEO, NYSERDAMs. Bridget Frymire, New York State Dept. of Public Service ATTACHMENT 1 TO NL-14-122ANALYSIS OF PROPOSED EXEGENT TECHNICALSPECIFICATION CHANGE REGARDING CHANGETO THE SURVEILLANCE REQUIREMENT 3.8.6.6ENTERGY NUCLEAR OPERATIONS, INC.INDIAN POINT NUCLEAR GENERATING UNIT NO. 2DOCKET NO. 50-247 NL-14-122Docket No. 50-247Attachment 1Page 1 of 61.0 DESCRIPTIONThis letter requests an amendment to Operating License DPR-26, Docket No. 50-247 for IndianPoint Nuclear Generating Unit No. 2 (IP2). The proposed change is to revise SurveillanceRequirement (SR) 3.8.6.6 of Technical Specification (TS) 3.8.6, "Battery Parameters" to allow achange to the acceptance criteria for the 22 Battery.Entergy has requested that this proposed change be processed as an exigent change per1OCFR50.91(a)(6), since insufficient time exists to provide a normal public comment periodprior to issuance of the amendment to resolve the concerns with the 22 Battery. Asdemonstrated below, there is no unreviewed safety question. The change is needed becauseof concerns that the 22 Battery will degrade and no longer meet SR 3.8.6.6 before the nextscheduled test. The station must be able to demonstrate the ability to meet the criteria in SR3.8.6.6 to ensure strict TS compliance. If the SR no longer meets SR 3.8.6.6 then SR 3.0.1requires the 22 Battery to be declared inoperable. Foreseeing the question regardingcompliance with the SR would be raised and there would be a need to revise the surveillanceacceptance criteria or shut down the plant could not reasonably have been foreseen oranticipated. TS SRs are designed to maintain components operable under TS until the nextscheduled surveillance unless there is objective evidence to the contrary.2.0 PROPOSED CHANGESRevise the SR 3.8.6.6 acceptance criteria for a performance discharge test or modifiedperformance discharge test to allow 22 Battery to use 80% rather than 85% battery capacityand revise the TS Bases 3.8.4 and 3.8.6 to reflect the change. The TS proposed change is:From"Verify battery capacity is -85% of the manufacturers rating when subjected to aperformance discharge test or a modified performance discharge test."To"Verify battery capacity is >- 85% L> 80% for Battery 22) of the manufacturer's ratingwhen subjected to a performance discharge test or a modified performance dischargetest."The associated Bases changes to TS 3.8.4 and 3.8.6 are in Attachment 3 for information.3.0 BACKGROUNDIP2 has four separate safety-related 125 volt (V) direct current (DC) systems that servevarious DC loads throughout the station. Each system consists of one battery, one batterycharger, one main power panel, and one or more DC distribution panels (sub panels). Each ofthe four batteries is composed of 58 lead-calcium storage cells connected to provide anominal terminal voltage of 125 V DC.

NL-14-122Docket No. 50-247Attachment 1Page 2 of 6Each battery charger is supplied from a different 480 V alternating current (AC) switchgearbus. Under normal conditions, the battery charger supplies the DC loads and float charges thebattery. The IP2 Updated Final Safety Analysis Report (UFSAR) states that the batteryprovides power to the DC loads under the following conditions:(a) When the load exceeds the capacity of the battery charger, such as during DC motorstarting or simultaneous breaker operation.(b) When the battery charger is not available, such as a battery charger failure or loss of inputvoltage.Each battery has been sized to carry its expected shutdown loads for a period of at least 2hours following a plant trip and a loss of all AC power. All equipment supplied by the batteriesis maintained operable with minimum expected voltages at the battery terminals during the 2hours. Each of the four battery chargers has been sized to recharge its own dischargedbattery within 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> while simultaneously carrying its normal load.Each battery is maintained under continuous charge by its associated self-regulatingbattery charger so that the batteries will always be at full charge in anticipation of a loss ofAC power incident. This ensures that adequate DC power will be available for starting andloading the emergency diesel generators and for other emergency uses.TS SR 3.8.6.6 currently requires the verification that battery capacity is > 85% of themanufacturer's rating when subjected to a performance discharge test or a modifiedperformance discharge test. The current acceptance criteria of > 85% represents a changefrom the original criteria of_> 80% made in Amendment 264 (the 80% criteria is the criteriacurrently in the Standard Technical Specification (STS) in brackets indicating it is the expectedcriteria but plant specific values should be used). The Entergy amendment corrected a non-conservative TS that was determined to exist during an engineering review. This change wasnot required for the 22 Battery but was made for consistency.As part of Amendment 264, it was noted that the battery sizing for IP2 was performed usingInstitute of Electrical and Electronics Engineers (IEEE) Standard 485-1997 "IEEERecommended Practice for Sizing Lead -Acid Batteries for Stationary Applications." The NRCstaff reviewed the general battery loading assumptions of calculation FEX-00062-01 (MinimumOperating Electrolyte Temperature for 125 V DC Batteries 21, 22, 23 and 24), used todetermine the 85% battery capacity, and calculation FEX-00204-01 (Station Battery 22 SystemCalculation). The NRC staff reviewed specific areas of the calculations to verify that theassumptions were consistent with IEEE 485-1997, endorsed by Regulatory Guide 1.212.4.0 TECHNICAL ANALYSISThe station battery load/discharge test is intended to show compliance with Tech Spec SR3.8.4.3, and SR 3.8.6.6. Indian Point Unit 2 is committed to following the battery monitoringand maintenance program of IEEE Standard 450-1995 as stated in Tech Spec 5.5.15, and thewording in SR 3.8.6.6 follows the IEEE Standard.The Basis for SR 3.8.6.6 indicates that the "acceptance criteria for this Surveillance areconsistent with IEEE-450 (Ref. 3) and IEEE-485 (Ref. 4). These references recommend thatthe battery be replaced if its capacity is below 80% of the manufacturer's rating. A capacity of NL-14-122Docket No. 50-247Attachment 1Page 3 of 680% shows that the battery rate of deterioration is increasing, even if there is ample capacity tomeet the load requirements. The acceptance criteria for this surveillance is batteryreplacement if capacity is below 85% of the manufacturer's rating, with the difference due toplant loading requirements, temperature limitations and the expected battery end-of-lifeconditions. Furthermore, the battery is sized to meet the assumed duty cycle loads when thebattery design capacity reaches this 85% limit. The Surveillance Frequency for this test isnormally 60 months. If the battery shows degradation, or if the battery has reached 85% of itsexpected life and capacity is < 100% of the manufacturer's rating, the Surveillance Frequencyis reduced to 12 months. However, if the battery shows no degradation but has reached 85%of its expected life, the Surveillance Frequency is only reduced to 24 months for batteries thatretain capacity _> 100% of the manufacturer's ratings. Degradation is indicated, according toIEEE-450 (Ref. 3), when the battery capacity drops by more than 10% relative to its capacity onthe previous performance test or when it is _> 10% below the manufacturer's rating. TheseFrequencies are consistent with the recommendations in IEEE-450 (Ref.3)."The 22 battery discharge test was performed during 2R21 and the test data evaluated onMarch 7, 2014. The result of the test was an 85.2% battery capacity with the temperaturecorrection factor. Previous battery testing was done in a manner that does not allow directtrending of the SR 3.8.6.6 test results:1. The original profile was based on the as-received capacity of 317 Amperes whichrepresented 90% of manufacturer's rated capacity with the expectation that the capacitywould grow to 100% within a few cycles. This as-received manufacturer's rating of 317Awas reclassified as the 100% of manufacturer's rated capacity and used thereafter asthe benchmark for determining Battery 22's capacity. Recently, this test profile waschanged to reflect the manufacturer's published rated capacity of 360 Amperes andwhen Battery 22 was tested to this profile during the 2014 Outage (2R21). As a resultof this change in methodology, Battery 22 showed a significant drop in capacity.2. There were several changes in the battery testing methodology at IP2. Previous batterytesting procedures at IP2 directed the performer to terminate the battery discharge testswhen capacities of 100% were reached. While this fulfilled the intent of the surveillanceit created an information gap in which there is no test data to show how much thebattery was actually above 100% capacity. This growth above 100% is expected asnew batteries are charged and discharged in the beginning of their service life.Revisions to the discharge tests have extended the test time from 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> to 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />, toensure that capacities greater than 100% were captured for trending purposes.3. The surveillance tests were also revised to incorporate battery discharge rates whichwere higher than those previously used based on the identification of non-conservativetesting criteria in previous revisions.Based on these changes, there is limited available historical data to directly comparecapacity drop over time while referencing the battery discharge rate. Entergy has assessedthe changes between the 2012 discharge test and the 2014 test and concluded that withtest changes made for the 2014 test the 2012 test result would have been 85.9% of batterycapacity.

NL-14-122Docket No. 50-247Attachment 1Page 4 of 6The Technical Specification as currently written, are subject to a presumption that thebattery is known to degrade and therefore there is no assurance that SR 3.8.6.6, whichrequires 85% of the manufacturers rating, continues to be met. Consequently, theapplication of SR 3.0.1 would require the plant to declare Battery 22 inoperable when the85% of manufacturers rating is no longer met or to shutdown and demonstrate it is metthrough testing. The enclosed calculation IP-CALC-14-00028, Revision 0 provides thebasis for a revised acceptance criteria of 80% of the manufacturers rating. Some of themore important points are1. The analysis for Battery 22 has always shown that it was capable of supplying itsdesign basis loading at 80% rated capacity. The original revision of calculation FEX-000204-01 Revision 0 showed that Battery 22 had adequate spare capacity (12.7%)while supplying its design loading at 85% of its rated capacity. Conservative loadingwas identified and removed from FEX-000204-01 Revision 0. This work wasincorporated in FEX-000204-01 Revision 1; its results show that spare capacityincreased to 36.14%. Calculation FEX-000204-01 Revision 1 is included in Enclosure 1as supporting documentation.2. The enclosed calculation, IP-CALC-14-00028 Revision 0, was issued, based wholly onFEX-00204-01 Revision 1, to demonstrate the spare capacity at an aging factor of 1.25(80% of its rated capacity). The result was a spare capacity of 28.06%. Therefore, ifBattery 22 is allowed to operate down to 80% of its rated capacity (1.25 aging factor),as supported by IEEE 450-1995 para. 7. IP-CALC-14-00028 Revision 0 demonstratesthat it is more than capable of performing its safety function. In fact, Battery 22 containssuch a large amount of spare capacity that a smaller battery cell size (a GN-21 type)can be used in the replacement battery.Entergy is currently planning to test or replace the 22 Battery and this will be complete by thedate for the next surveillance due date on March 7, 2015. The replacement battery will be likein kind so that the capacity factor of 80% will be appropriate.5.0 REGULATORY ANALYSIS5.1 No Significant Hazards ConsiderationEntergy has evaluated the proposed Technical Specification change using the criteria of1 OCFR50.92 and found that no significant hazards consideration exist for the followingreasons:1) Does the proposed License amendment involve a significant increase in theprobability or consequences of an accident previously evaluated?Response: No.The proposed change revises the acceptance criterion applied to an existing surveillancetest for the Indian Point 2 station battery 22 discharge test. Performing a technicalspecification surveillance test is not an accident initiator and does not increase theprobability of an accident occurring. The proposed revision to the test acceptance criterionis based on the design calculation for battery performance and an assessment of the NL-14-122Docket No. 50-247Attachment 1Page 5 of 6acceptability of the lower acceptance criterion for the discharge test. The proposed newvalue for the test acceptance criteria is less limiting than the existing value but meetsoperability criterion. Establishing a test acceptance criterion that meets plant criterionvalidates the equipment performance assumptions used in the accident mitigation safetyanalyses. Therefore the proposed change does not involve a significant increase in theprobability or consequences of an accident previously evaluated.2) Does the proposed License amendment create the possibility of a new or differentkind of accident from any accident previously evaluated?Response: No.The proposed change revises the test acceptance criterion for an existing technicalspecification surveillance test conducted on the 22 station battery. The proposed changedoes not involve installation of new equipment or modification of existing equipment, so thatno new equipment failure modes are introduced. Also, the proposed change in testacceptance criterion does not result in a change to the way that the equipment or facility isoperated so that no new accident initiators are created. Therefore the proposed changedoes not create the possibility of a new or different kind of accident from any accidentpreviously evaluated.3) Does the proposed License amendment involve a significant reduction in a marginof safety?Response: No.No. The conduct of performance tests on safety-related plant equipment is a means ofassuring that the equipment is capable of performing its intended safety function andtherefore maintaining the margin of safety established in the safety analysis for the facility.The proposed change in the acceptance criterion for the 22 battery capacity surveillancetest is less conservative and less restrictive than the overly conservative value currently inthe technical specification. The proposed change is based on the applicable designcalculation for these components and meets IEEE criteria,.Based on the above, Entergy concludes that the proposed amendment to the Indian Point 2Technical Specifications presents no significant hazards consideration under the standards setforth in 10 CFR 50.92(c), and accordingly, a finding of 'no significant hazards consideration' isjustified5.2 Applicable Requlatory Requirements / CriteriaIP2 was designed to the proposed Atomic Industrial Forum versions of the criteria issued forcomment by the AEC on July 11, 1967. The applicable criteria are General Design Criteria(GDC) 24 and 39 which specify that an emergency power source shall be provided anddesigned with adequate independency, redundancy, capacity, and testability to permit thefunctioning of the engineered safety features and protection systems required to avoid unduerisk to the health and safety of the public. This power source shall provide this capacityassuming a failure of a single component. These criteria, found in Section 8.1 of the UFSAR,continue to be met with this proposed change because the 22 battery remains functional andtherefore the design remains compliant.

NL-14-122Docket No. 50-247Attachment 1Page 6 of 6Although not licensed to the GDC, IP2 was evaluated against them in response to the February11, 1980 confirmatory order. Compliance with these specific criteria is maintained because the22 battery remains functional and therefore the design remains compliantGDC 17; "Electrical Power Systems", requires that onsite electrical power systems havesufficient independence, capacity, capability, redundancy and testability to ensure the (1)specified acceptable fuel design limits and design conditions of the reactor coolant pressureboundary are not exceeded as a result of anticipated operational occurrences, and (2) the coreis cooled and containment integrity and other vital functions are maintained in the event ofpostulated accidents, assuming a single failure.GDC 18; "Inspection and Testing of Electrical Power Systems", requires that electrical powersystems important to safety be designed to permit appropriate periodic inspection and testingto assess the continuity of systems and the conditions of their components. During the TSchange these criterion continue to be met.IP2 UFSAR section 8.1 describes how the requirements of GDC 17 and 18 are met at IP2,including for the safety-related 125 VDC electrical power subsystem, which consists of fourseparate trains of batteries, battery chargers, and associated power distribution panels. Undernormal conditions, each battery charger supplies its DC loads, while maintaining its associatedbattery at full charge. Each battery provides power to its DC loads when its associated batterycharger is not available. Each battery has been sized to carry its expected shutdown loads fora period of 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> following a plant trip and a loss of all AC power. All equipment supplied bythe batteries is maintained operable with minimum expected voltages at the battery terminalsduring the 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />.5.3 Environmental ConsiderationsThe proposed changes to the IP2 Technical Specifications do not involve (i) a significanthazards consideration, (ii) a significant change in the types or significant increase in theamounts of any effluent that may be released offsite, or (iii) a significant increase inindividual or cumulative occupational radiation exposure. Accordingly, the proposedamendment meets the eligibility criterion for categorical exclusion set forth in 10 CFR51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statementor environmental assessment need be prepared in connection with the proposedamendment.

6.0 REFERENCES

1. NRC Letter to Entergy regarding TS Amendment 264, dated February 24, 2010.

ATTACHMENT 2 TO NL-14-122MARKUP OF TECHNICAL SPECIFICATION FORCHANGE TO SURVEILLANCE REQUIREMENT 3.8.6.6Changes indicated by lineout for deletion and Bold/Italics for additionsUnit 2 Affected Pages:TS 3.8.6 -4ENTERGY NUCLEAR OPERATIONS, INC.INDIAN POINT NUCLEAR GENERATING UNIT NO. 2DOCKET NO. 50-247 Battery Parameters3.8.6SURVEILLANCE REQUIREMENTS (continued)SURVEILLANCE FREQUENCYSR 3.8.6.5 Verify each battery connected cell voltage is > 2.07 V. 92 daysSR 3.8.6.6-NOTE -This Surveillance shall not be performed in MODE 1, 2,3, or 4. However, credit may be taken for unplannedevents that satisfy this SR.Verify battery capacity is _ 85% (80% for Battery 22) ofthe manufacturer's rating when subjected to aperformance discharge test or a modified performancedischarge test.60 monthsAND12 months whenbattery showsdegradation, orhas reached 85%of the expectedlife with capacity< 100% ofmanufacturer'sratingAND24 months whenbattery hasreached 85% ofthe expected lifewith capacity___ 100% ofmanufacturer'sratingINDIAN POINT 23.8.6 -4Amendment No. 264 ATTACHMENT 3 TO NL-14-122MARKUP OF TS BASES 3.8.4 AND 3.8.6 CHANGES ASSOCIATEDWITH SURVEILLANCE REQUIREMENT 3.8.6.6 REVISIONChanges indicated by lineout for deletion and Bold/Italics for additionsUnit 2 Affected Bases Pages:B 3.8.4 -3B 3.8.6 -7ENTERGY NUCLEAR OPERATIONS, INC.INDIAN POINT NUCLEAR GENERATING UNIT NO. 2DOCKET NO. 50-247 DC Sources -OperatingB 3.8.4BASESBACKGROUND (continued)The batteries are sized to produce required capacity at 85% (80% forBattery 22) of nameplate rating, corresponding to expected capacity at endof life cycles and the 100% design demand. The minimum design voltagelimit is 105 V.The battery cells are lead calcium construction with a nominal specificgravity of 1.215. This specific gravity corresponds to an open circuit batteryvoltage of approximately 120 V for a 58 cell battery (i.e., cell voltage of2.06 volts per cell (Vpc)). The open circuit voltage is the voltage maintainedwhen there is no charging or discharging. Optimal long term performancehowever, is obtained by maintaining a float voltage of approximately 2.20 to2.25 Vpc. The nominal float voltage of 2.20 to 2.25 Vpc corresponds to atotal float voltage output of approximately 130 V for a 58 cell battery.Each of the four DC electrical power subsystem battery chargers has amplepower output capacity for the steady state operation of connected loadsrequired during normal operation, while at the same time maintaining itsbattery bank fully charged. Each battery charger also has sufficient excesscapacity to restore the battery from the design minimum charge to its fullycharged state within 15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br /> while supplying normal steady state loadsdiscussed in the UFSAR, Chapter 8 (Ref. 4).The battery charger is normally in the float-charge mode. Float-charge is thecondition in which the charger is supplying the connected loads and thebattery cells are receiving adequate current to optimally charge the battery.This assures the internal losses of a battery are overcome and the battery ismaintained in a fully charged state.When desired, the charger can be placed in the equalize mode. Theequalize mode is at a higher voltage than the float mode and chargingcurrent is correspondingly higher. The battery charger is operated in theequalize mode after a battery discharge or for routine maintenance.Following a battery discharge, the battery recharge characteristic acceptscurrent at the current limit of the battery charger (if the discharge wassignificant, e.g., following a battery service test) until the battery terminalvoltage approaches the charger voltage setpoint. Charging current thenreduces exponentially during the remainder of the rechargecycle. Lead-calcium batteries have recharge efficiencies of greater than95%, so once at least 105% of the ampere-hours discharged have beenreturned, the battery capacity would be restored to the same condition as itwas prior to the discharge. This can be monitored by direct observation ofthe exponentially decaying charging current or by evaluating the amp-hoursdischarged from the battery and amp-hours returned to the battery.INDIAN POINT 2B 3.8.4 -3Revision 5 Battery ParametersB 3.8.6BASESSURVEILLANCE REQUIREMENTS (continued)SR 3.8.6.6A battery performance discharge test is a test of constant current capacity ofa battery, normally done in the as found condition, after having been inservice, to detect any change in the capacity determined by the acceptancetest. The test is intended to determine overall battery degradation due toage and usage.Either the battery performance discharge test or the modified performancedischarge test is acceptable for satisfying SR 3.8.6.5; however, only themodified performance discharge test may be used to satisfy the batteryservice test requirements of SR 3.8.4.3.A modified discharge test is a test of the battery capacity and its ability toprovide a high rate, short duration load (usually the highest rate of the dutycycle). This will often confirm the battery's ability to meet the critical periodof the load duty cycle, in addition to determining its percentage of ratedcapacity. Initial conditions for the modified performance discharge testshould be identical to those specified for a service test.It may consist of just two rates; for instance the one minute rate for thebattery or the largest current load of the duty cycle, followed by the test rateemployed for the performance test, both of which envelope the duty cycle ofthe service test. Since the ampere-hours removed by a one minutedischarge represents a very small portion of the battery capacity, the testrate can be changed to that for the performance test without compromisingthe results of the performance discharge test. The battery terminal voltagefor the modified performance discharge test must remain above theminimum battery terminal voltage specified in the battery service test for theduration of time equal to that of the service test.The acceptance criteria for this Surveillance are consistent with themethodology of IEEE-450 (Ref. 3) and IEEE-485 (Ref. 4). These referencesrecommend that the battery be replaced if its capacity is below 80% of themanufacturer's rating. A capacity of 80% shows that the battery rate ofdeterioration is increasing, even if there is ample capacity to meet the loadrequirements. The acceptance criteria for this surveillance is batteryreplacement if capacity is below 85% (80% for Battery 22) of themanufacturers rating, with the difference due to plant loading requirements,temperature limitations and the expected battery end-of-life conditions.Furthermore, the battery is sized to meet the assumed duty cycle loadswhen the battery design capacity reaches this 85% (80% for Battery 22)limit.INDIAN POINT 2B 3.8.6 -7Revision 2