Text

Application to Revise Technical Specifications Regarding DC Electrical Systems TStf-500, Revision 2, DC Electrical Rewrite - Update to TSTF-360 (WBN-TS-18-09)
	ML18334A389
Person / Time
Site:	Watts Bar
Issue date:	11/29/2018
From:	Henderson E; Tennessee Valley Authority
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	CNL-18-118, WBN-TS-18-09
	Download: ML18334A389 (225)
	v • d • e

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-18-118 November 29, 2018 10 CFR 50.90 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 Docket No. 50-390 Watts Bar Nuclear Plant, Unit 2 Facility Operating License No. NPF-96 Docket No. 50-391

Subject:

Application to Revise Technical Specifications Regarding DC Electrical Systems TSTF-500, Revision 2, DC Electrical Rewrite - Update to TSTF -360 (WBN-TS-18-09)

In accordance with the provisions of Title 10 of the Code of Federal Regulations (10 CFR) 50.90, "Application for amendment of license, construction permit, or early site permit," Tennessee Valley Authority (TVA) is submitting a request for an amendment to the technical specifications (TS) for Watts Bar Nuclear Plant (WBN), Units 1 and 2.

The proposed amendment would modify TS requirements related to direct current (DC) electrical systems in accordance with Technical Specification Task Force (TSTF) Traveler TSTF-500, Revision 2, DC Electrical Rewrite - Update to TSTF-360. provides a description and assessment of the proposed change including the requested confirmation of applicability and plant-specific verifications, technical analyses, regulatory analyses, and environmental considerations. Enclosure 2 provides markups of the existing TS and Bases pages to show the proposed changes. Enclosure 3 provides revised (clean) TS pages. Enclosure 4 provides a summary of the regulatory commitments made in this submittal. Enclosure 5 provides copies of letters from battery manufacturers verifying the acceptability of using float current monitoring. Enclosure 6 provides an evaluation of extending the Completion Time for TS 3.8.4, DC Sources - Operating, Required Action A.3.

U.S. Nuclear Regulatory Commission CNL-18-118 Page 2 November 29, 2018 The WBN Plant Operations Review Committee has reviewed this proposed change and determined that operation of WBN Units 1 and 2 in accordance with the proposed change will not endanger the health and safety of the public.

TVA has determined that there are no significant hazard considerations associated with the proposed change and that the change qualifies for a categorical exclusion from environmental review pursuant to the provisions of 10 CFR 51 .22(c)(9). Additionally, in accordance with 10 CFR 50.91 (b)(1 ), TVA is sending a copy of this letter and the enclosures to the Tennessee Department of Environment and Conservation.

TVA requests approval of the proposed license amendment within one year from the date of this submittal, with implementation of the amendment within 90 days to support the WBN Unit 1 Cycle 16 refueling outage scheduled for Spring 2020. contains the new commitments in this submittal. Please address any questions regarding this request to Michael A. Brown at (423) 751-3275.

I declare under penalty of perjury that the foregoing is true and correct. Executed on this 29th day of November 2018.

z:y,~

Erin K. Henderson Director, Nuclear Regulatory Affairs

Enclosures:

1. Description and Assessment of Proposed Change

2. Markups of Technical Specification and Bases Changes

3. Clean Technical Specification and Bases Changes

4. Regulatory Commitments

5. Letters from Battery Manufacturers Verifying the Acceptability of Using Float Current Monitoring

6. Evaluation of an Extended Completion Time for Technical Specification 3.8.4, Required Action A.3 cc (Enclosures):

NRC Regional Administrator - Region II NRC Project Manager - Watts Bar Nuclear Plant NRC Senior Resident Inspector - Watts Bar Nuclear Plant Director, Division of Radiological Health - Tennessee State Department of Environment and Conservation

Enclosure 1 Description and Assessment of Proposed Change

Subject:

Application to Revise Technical Specifications Regarding DC Electrical Systems TSTF-500, Revision 2, DC Electrical Rewrite - Update to TSTF-360 (WBN-TS-18-09)

TABLE OF CONTENTS

1.0 DESCRIPTION

................................................................................................................ 2 2.0 ASSESSMENT ................................................................................................................ 3 2.1 Applicability of TSTF-500 and Model Safety Evaluation ............................................... 3 2.2 Verifications and Required Final Safety Analysis Report Changes............................... 6 2.3 Optional Changes and Variations................................................................................. 8

3.0 REGULATORY ANALYSIS

............................................................................................. 8 3.1 No Significant Hazards Consideration Determination ................................................... 8 3.2 Applicable Regulatory Requirements/Criteria ..............................................................10

4.0 ENVIRONMENTAL CONSIDERATION

..........................................................................10

5.0 REFERENCES

...............................................................................................................11 CNL-18-118 E1-1 of 11

Enclosure 1 Description and Assessment of Proposed Change

1.0 DESCRIPTION

In accordance with the provisions of Title 10 of the Code of Federal Regulations (10 CFR) 50.90, "Application for amendment of license, construction permit, or early site permit," Tennessee Valley Authority (TVA) is submitting a request for an amendment to the technical specifications (TS) for Watts Bar Nuclear Plant (WBN) Unit 1 and Unit 2.

The TS requirements are being revised from requirements on battery cells to requirements on the battery. This focuses the requirements on the assumed safety function of the battery. The proposed amendment would modify TS requirements related to direct current (DC) electrical systems in Limiting Condition for Operation (LCO) 3.8.4, DC Sources - Operating, LCO 3.8.5, DC Sources - Shutdown, and LCO 3.8.6, Battery Cell Parameters. A new Battery Monitoring and Maintenance Program is being proposed for Section 5.7.2, Programs and Manuals.

Specifically, the proposed change requests new actions for an inoperable battery charger and alternate battery charger testing criteria for LCO 3.8.4 and LCO 3.8.5. The proposed change also includes the relocation of a number of Surveillance Requirements (SRs) in TS 3.8.4 that perform preventive maintenance on the safety-related batteries to a licensee-controlled program. It is proposed that LCO 3.8.6 be modified by relocating Table 3.8.6-1, Battery Cell Parameter Requirements, to a licensee-controlled program, and that specific actions with associated Completion Times (CTs) for out-of-limits conditions for battery cell voltage, electrolyte level, and electrolyte temperature be added to TS 3.8.6. In addition, specific SRs are being proposed for verification of these parameters.

A new program is being proposed for Section 5.7.2 of the Administrative Controls for the maintenance and monitoring of station batteries. The items proposed to be relocated will be contained within this program, titled the Battery Monitoring and Maintenance Program.

The proposed change provides new Actions for an inoperable battery charger and alternate battery charger testing criteria. The longer CT for an inoperable battery charger will allow additional time for maintenance and testing. In addition, a number of SRs are relocated to licensee control including the monitoring of battery cell parameter requirements and performance of battery maintenance activities.

The changes are consistent with Nuclear Regulatory Commission (NRC)-approved Technical Specification Task Force (TSTF) Traveler TSTF-500, Revision 2 (TSTF-500)

(Reference 1). The availability of this TS improvement was published in the Federal Register on September 1, 2011 (76 FR 54510) (Reference 2), as supplemented on November 8, 2011 (76 FR 69296) (Reference 3).

The changes to the TS and Bases are consistent with the changes contained in TSTF-500, Revision 2, Attachment B, as they apply to NUREG-4131, Revision 1.0, as the current WBN Units 1 and 2 TS do not reflect the adoption of TSTF-360.

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Enclosure 1 Description and Assessment of Proposed Change 2.0 ASSESSMENT 2.1 APPLICABILITY OF TSTF-500 AND MODEL SAFETY EVALUATION TVA has reviewed the model Safety Evaluation (SE) referenced in the Federal Register Notice of Availability published on September 1, 2011 (76 FR 54510). The review included the NRC staff's SE, as well as the supporting information provided in TSTF-500. As described herein, TVA has concluded that the technical bases for the proposed changes presented in TSTF-500 and the model SE prepared by the NRC staff are applicable to WBN and support incorporation of this amendment into the WBN Unit 1 and Unit 2 TS.

The current WBN TS 3.8.4, 3.8.5, and 3.8.6 include requirements for the emergency diesel generators (DGs) 125 V DC electrical power subsystems. Therefore, the proposed WBN TS use different numbering than the Standard TS (STS) (NUREG-1431) on which TSTF-500 is based.

The WBN TS 3.8.4, 3.8.5, and 3.8.6 include separate Conditions, Required Actions, and Surveillance Requirements for the DG DC electrical power subsystems to reflect the differences in the designs for the vital DC and DG DC electrical power subsystems. The design of the vital DC subsystems supports a 7-day CT for an inoperable battery charger and the design of the DG DC subsystem does not support a CT longer than 72-hour for an inoperable battery charger. In addition, the minimum established float voltage for the vital DC batteries is less than or equal to 2 amps and the minimum established float current for the DG DC batteries is less than or equal to 1 amp. Although these differences necessitate additional Conditions, Required Actions, and Surveillance Requirements to accommodate the differences between the vital DC and DG DC electrical power subsystems, they do not affect the applicability of the model SE to the WBN Unit 1 and 2 TS.

An additional numbering difference occurs between TSTF-500 and the WBN Unit 1 and Unit 2 TS with the addition of the "Battery Monitoring and Maintenance Program. The Battery Monitoring and Maintenance Program is contained in TS 5.7.2.22, as opposed to TS 5.5.14, as indicated in TSTF-500. This difference is editorial and does not affect the applicability of TSTF-500 to the WBN Unit 1 and Unit 2 TS.

The WBN DC system is similar to the system described in TSTF-500, with respect to its ability to meet the duty cycle assumed in the accident analyses and with its operations in the float and equalize modes. The WBN 125 V Vital DC electrical power system consists of a combined Unit 1 and Unit 2 system, each separated into two independent Class 1E DC electrical power subsystems per unit. A description of the 125 V vital DC Control System is contained in Enclosure 6. Following is a description of the DG 125V DC Control System.

Design Features of the Diesel Generator 125V DC Control System A DG battery subsystem is provided for each DG. Each subsystem is comprised of a battery, dual battery charger assembly, distribution center, and cabling. The DG battery provides DC control power and field-flash when the charger is unavailable. If 480V AC is available, the charger supplies the normal DC loads, maintains the battery in a fully CNL-18-118 E1-3 of 11

Enclosure 1 Description and Assessment of Proposed Change charged condition, and recharges the battery while supplying the required loads regardless of the status of the plant. The batteries are physically and electrically independent. The DG control power systems are ungrounded and have ground detection instrumentation. Each DG battery has sufficient capacity when fully charged to supply the required loads for a minimum of four-hours following a loss of normal power.

Battery capacity design requirements consider minimum required voltage for loads and the effects of aging and ambient temperature. Each battery is normally required to supply loads only during the time interval between loss of normal feed to its charger and the receipt of emergency power to the charger from its respective diesel-generator. The batteries, comprised of 58 cells, have adequate capacity considering the minimum terminal voltage of 105 volts and derating for 50°F temperature and aging.

The normal supply of DC current to the battery boards is from the battery charger. Each charger maintains a float voltage of approximately 130 volts on the associated battery board with the battery connected to the board and is capable of maintaining 135 volts during an equalizing charge period (all loads can tolerate approximately 135V equalizing voltage). Each of the chargers (normal and alternate) in the dual charger assembly has a dedicated AC source from two respective 480V AC Diesel Generator Auxiliary Boards.

If the normal charger is unavailable, the alternate charger is selected by the 125V DC transfer switch included in the assembly. The charger is a solid-state type that converts a 3-phase 480V AC input to a nominal 125V DC output. The DC output voltage will vary no more than +/- 1.0% for a supply voltage amplitude variation of +/- 10% and frequency variation of +/- 2.0%. Some operational features of the chargers are:

(1) an output voltage adjustable over the range of 125 to 135 volts, (2) equalize and float modes of operation (the charger normally operates in the float mode at 130 volts, but can be switched to the equalize mode with an output of 135 volts),

(3) a current-limit feature that limits continuous overload operation to approximately 140% of rated output, (4) protective devices which prevent a failed charger from loading the battery, and (5) metering and alarm circuits to monitor the charger output.

Differences Between WBN Unit 1 and Unit 2 TS and TSTF-500 The WBN Unit 1 and Unit 2 TS differ from the Standard TS (STS) (NUREG-1431) which were the basis for TSTF-500, Revision 2, in the following ways:

WBN Unit 1 and Unit 2 LCO 3.8.4 refer to four channels of vital DC. NUREG-1431 LCO 3.8.4 refers to Train A and Train B vital DC electrical power subsystems. The WBN Unit 1 and Unit 2 TS are being revised to adopt the NUREG-1431 language.

This change aligns the LCO statement to the current Condition A statement regarding One vital DC electrical power subsystem inoperable. This change reflects the design of the vital DC electrical power subsystems that requires either Train A (Channels I and III) or Train B (Channels II and IV) to perform the safety function associated with the vital DC electrical power subsystems for WBN Unit 1 and Unit 2. This change aligns the WBN Unit 1 and Unit 2 TS to TSTF-500 and therefore, does not affect the applicability of the published model SE.

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Enclosure 1 Description and Assessment of Proposed Change

WBN Unit 1 LCO 3.8.4 and LCO 3.8.5 are modified by a Note that allows the C-S DG and its associated DC electrical Power subsystem to be substituted for any of the required DGs and their associated DC electrical power subsystem. As documented in Reference 4, the WBN C-S DG is not being maintained. Therefore, the C-S DG cannot meet the requirements specified in TS 3.8.1 Bases that would allow it to be substituted for any required DG. Removal of a similar Note in WBN Unit 1 LCO 3.8.1, AC Sources - Operating, was approved by the NRC in Reference 5. These differences do not affect the applicability of the published model SE.

WBN Unit 1 and Unit 2 were designed with five qualified class 1E, safety-related vital batteries and eight qualified class 1E, safety-related vital battery chargers.

The fifth vital battery serves as a replacement for any one of the other four vital batteries during their testing, maintenance, and outages with no loss of system reliability under any mode of operation. Each of the four battery boards has a charger normally connected and has access to a spare charger for use upon loss of the normal charger. Based on the operational flexibility of the vital DC system, a loss of one battery on one subsystem does not require a subsystem to be considered inoperable once the fifth battery is adequately surveilled and connected. Therefore, LCO 3.8.4 is modified by a note that allows vital battery V to be substituted for vital battery I, II, III, or IV. In addition, TS 3.8.4, Condition A, and TS 3.8.5, Condition A, are revised to state one or two "required" vital battery charger(s) on one subsystem inoperable. Because this change does not alter the intended application of the LCO and its related Actions, the change is considered a minor variation from TSTF-500.

The WBN vital DC batteries and the DG DC batteries have different required float currents for determining that their respective batteries are charged. Therefore, the proposed WBN Unit 1 and Unit 2 TS include separate Action Conditions for inoperable batteries and battery chargers for the vital DC and DG DC electrical power subsystems. The additional Action Conditions for the DG DC electrical power subsystem is consistent with the current technical specifications and results in a numbering difference for the Action Conditions. These differences do not affect the applicability of the published model SE.

The WBN vital DC and the DG DC electrical power subsystems have different required float voltages for verifying the effectiveness of the associated battery chargers. Therefore, the proposed WBN Unit 1 and Unit 2 TS include SR 3.8.4.1 for vital DC electrical power subsystem and SR 3.8.4.2 for DG DC electrical power subsystem. The additional SR for the DG DC electrical power subsystem is in the current technical specifications and results in a difference in the SR numbering.

These differences do not affect the applicability of the published model SE.

The WBN vital DC and the DG DC electrical power subsystem battery chargers have different design capacities and performance characteristics. Therefore, there are separate SRs to verify the capacity of the charger to restore the associated battery from the design minimum charge state to the fully charged state, irrespective of the status of the plant during the demand occurrence. The additional SR for the DG DC electrical power subsystem is in the current technical CNL-18-118 E1-5 of 11

Enclosure 1 Description and Assessment of Proposed Change specifications and results in a difference in the SR numbering. These differences do not affect the applicability of the published model SE.

2.2 VERIFICATIONS AND REQUIRED FINAL SAFETY ANALYSIS REPORT CHANGES As described in Section 4.7.1, Verifications, in TSTF-500, TVA provides the following verifications.

1. Enclosure 5 contains letters from the manufacturers of the batteries used at WBN Units 1 and 2 verifying the acceptability of using float current monitoring instead of specific gravity monitoring as a reliable and accurate indication of the state-of-charge of the battery and that this will hold true over the life of the battery.

2. As indicated in Enclosure 4, TVA commits to verify that the equipment that will be used to monitor float current under SR 3.8.6.1 and SR 3.8.6.2 will have the necessary accuracy and capability to measure electrical currents in the expected range. Additionally, TVA commits to verify that the minimum required procedural time to measure battery float current will be 30 seconds or as recommended by the float current measurement instrument manufacturer. This minimum float current measurement time is required to provide a more accurate battery float current reading.

3. TVA verifies that battery room temperature is routinely monitored such that a room temperature excursion could reasonably expect to be detected and corrected prior to the average battery electrolyte temperature dropping below the minimum electrolyte temperature.

4. Enclosure 6 contains a description of the 125V DC vital system, including a discussion of the battery chargers, spare battery chargers, capability of the batteries to be charged from a power source that is independent of the offsite power supply, and a description of the onsite standby power supply that can be used to power the battery chargers.

5. Not applicable. TVA is not requesting a CT greater than 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months for TS 3.8.4, Required Action B.1 or C.1.

6. The cell resistance limits in existing SR 3.8.4.5 and SR 3.8.4.6 are relocated to the "Battery Monitoring and Maintenance Program." The cell connection resistance limits listed in the table below are based on vendor recommendations. The resistance limits apply to overall connection resistance and allows for normal degradation while maintaining battery operability.

Connection Vital Batteries DG Batteries (Ohm) (Ohm)

Inter-cell 80 80 Inter-rack 50 50 Inter-tier 120 50 Terminal Connections 50 50 CNL-18-118 E1-6 of 11

Enclosure 1 Description and Assessment of Proposed Change

7. TVA is proposing to delete the SR 3.8.4.13 (new SR 3.8.4.7) Note once per 60 months restriction on performing the modified performance discharge test instead of the service test. TVA verifies that the modified performance discharge test completely encompasses the load profile of the battery service test and that it adequately confirms the intent of the service test to verify the battery capacity to supply the design basis load profile.

8. As indicated in Enclosure 4, TVA commits to relocating the monitoring of battery parameters (i.e., specific gravity, electrolyte level, cell temperature, float voltage, connection resistance, and physical condition) to the licensee-controlled program, required and described in TS Section 5.7, Programs, Programs, and Manuals, and titled the Battery Monitoring and Maintenance Program.

9. As indicated in Enclosure 4, TVA commits to verifying that plant procedures will require verification of the selection of the pilot cell or cells when performing SR 3.8.6.5.

The Model SE, Attachment 2, List of Required Final Analysis Report (FSAR)

Descriptions, indicates several statements that are required to be included in the FSAR.

As indicated in Enclosure 4 of this letter, TVA commits to revising the FSAR to include the following, as part of the adoption of TSTF-500, Revision 2:

1. How a two percent design margin for the vital batteries corresponds to a two-amp float current value indicating that the battery is at least 98 percent charged.

2. How a 2 percent design margin for the DG batteries corresponds to a one-amp float current value indicating that the battery is at least 98 percent charged.

3. How long term battery performance is obtained by maintaining a float voltage greater than or equal to the minimum established design limits provided by the battery manufacturer.

4. How the batteries are sized with correction margins that include temperature and aging and how these margins are maintained.

5. The minimum established design limit for battery terminal float voltage.

6. The minimum established design limit for electrolyte level.

7. The minimum established design limit for electrolyte temperature.

8. How each battery is designed with additional capacity above that required by the design duty cycles to allow for temperature variations and other factors.

9. Normal DC system operation i.e., powered from the battery chargers with the batteries floating on the system, and with a loss of normal power to the battery charger.

10. The minimum requirements for the alternate means (i.e., spare battery charger) that are used to obtain an extended battery charger CT.

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Enclosure 1 Description and Assessment of Proposed Change 2.3 OPTIONAL CHANGES AND VARIATIONS TVA is proposing the following variation from the TS changes described in the TSTF-500, Revision 2, or the applicable parts of the NRC staffs model SE referenced in the Federal Register on September 1, 2011 (76 FR 54510), as supplemented on November 8, 2011 (76 FR 69296). These options were recognized as acceptable variations in TSTF-500 and the NRC staff's model SE.

TVA is proposing a CT longer than 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months for TS 3.8.4, Required Action A.3, and TS 3.8.5, Required Action A.3. An evaluation is included as Enclosure 6, which supports the longer CT and describes the availability of a spare battery charger and that the battery charger is appropriately sized. The CT is consistent with the WBN Units 1 and 2 UFSAR description that a means to charge the batteries is available and that the capability includes power supplied from a source that is independent of the offsite power supply. A description of the power source is also included.

TVA is not requesting a Completion Time longer than 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months to restore battery float current with one or two required battery chargers on one subsystem inoperable (TSTF-500, TS 3.8.4, Required Action A.2, and TS 3.8.5, Required Action A.2).

TVA is not requesting a Completion Time longer than 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months for one or two batteries on one subsystem inoperable (TSTF-500, TS 3.8.4, Required Action B.1). Therefore, as there is no difference in the Completion Time for Required Action B.1 and the Completion Time for Required Action C.1, TVA is not adopting TSTF-500, TS 3.8.4, Condition B.

WBN Unit 1 and Unit 2 implementation of TSTF-500, as it applies to LCO 3.8.5, includes adoption of new Action A, as the potential exists to require both vital DC electrical power subsystems during a portion of the LCO 3.8.5 applicability.

3.0 REGULATORY ANALYSIS

3.1 NO SIGNIFICANT HAZARDS CONSIDERATION DETERMINATION Tennessee Valley Authority (TVA) has evaluated the proposed changes to the TS using the criteria in Section 50.92 to Title 10 of the Code of Federal Regulations (10 CFR) and has determined that the proposed changes do not involve a significant hazards consideration.

The proposed amendment would revise TS requirements related to direct current (DC) electrical systems in TS limiting condition for operation (LCO) 3.8.4, DC Sources -

Operating, LCO 3.8.5, DC Sources - Shutdown, and LCO 3.8.6, Battery Cell Parameters. A new Battery Monitoring and Maintenance Program is being proposed for Section 5.7.2, Programs and Manuals. As required by 10 CFR 50.91(a), the TVA analysis of the issue of no significant hazards consideration is presented below:

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Enclosure 1 Description and Assessment of Proposed Change

1. Does the proposed change involve a significant increase in the probability or consequences of any accident previously evaluated?

Response: No.

The proposed changes restructure the Technical Specifications (TS) for the direct current (DC) electrical power system and are consistent with TSTF-500, Revision 2. The proposed changes modify TS Actions relating to battery and battery charger inoperability. The DC electrical power system, including associated battery chargers, is not an initiator of any accident sequence analyzed in the Final Safety Analysis Report (FSAR). Rather, the DC electrical power system supports equipment used to mitigate accidents. The proposed changes to restructure TS and change surveillances for batteries and chargers to incorporate the updates included in TSTF-500, Revision 2, will maintain the same level of equipment performance required for mitigating accidents assumed in the FSAR. Operation in accordance with the proposed TS would ensure that the DC electrical power system is capable of performing its specified safety function as described in the FSAR. Therefore, the mitigating functions supported by the DC electrical power system will continue to provide the protection assumed by the analysis.

The relocation of preventive maintenance surveillances, and certain operating limits and actions, to a licensee-controlled Battery Monitoring and Maintenance Program will not challenge the ability of the DC electrical power system to perform its design function.

Appropriate monitoring and maintenance that are consistent with industry standards will continue to be performed. In addition, the DC electrical power system is within the scope of 10 CFR 50.65, Requirements for monitoring the effectiveness of maintenance at nuclear power plants, which will ensure the control of maintenance activities associated with the DC electrical power system.

The integrity of fission product barriers, plant configuration, and operating procedures as described in the FSAR will not be affected by the proposed changes. Therefore, the consequences of previously analyzed accidents will not increase by implementing these changes. Therefore, the proposed changes do not involve a significant increase in the probability or consequences of an accident previously evaluated.

2. Does the proposed change create the possibility of a new or different kind of accident from any previously evaluated?

Response: No The proposed changes involve restructuring the TS for the DC electrical power system.

The DC electrical power system, including associated battery chargers, is not an initiator to any accident sequence analyzed in the FSAR. Rather, the DC electrical power system supports equipment used to mitigate accidents. The proposed changes to restructure the TS and change surveillances for batteries and chargers to incorporate the updates included in TSTF-500, Revision 2, will maintain the same level of equipment performance required for mitigating accidents assumed in the FSAR. Administrative and mechanical controls are in place to ensure the design and operation of the DC systems continues to meet the plant design basis described in the FSAR. Therefore, operation of the facility in accordance with this proposed change will not create the possibility of a new or different kind of accident from any accident previously evaluated.

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Enclosure 1 Description and Assessment of Proposed Change

3. Does the proposed change involve a significant reduction in the margin of safety?

Response: No.

The margin of safety is established through equipment design, operating parameters, and the setpoints at which automatic actions are initiated. The equipment margins will be maintained in accordance with the plant-specific design bases because of the proposed changes. The proposed changes will not adversely affect operation of plant equipment. These changes will not result in a change to the setpoints at which protective actions are initiated. Sufficient DC capacity to support operation of mitigation equipment is ensured. The changes associated with the new battery Maintenance and Monitoring Program will ensure that the station batteries are maintained in a highly reliable manner. The equipment fed by the DC electrical sources will continue to provide adequate power to safety-related loads in accordance with analysis assumptions. TS changes made in accordance with TSTF-500, Revision 2, maintain the same level of equipment performance stated in the FSAR and the current TSs. Therefore, the proposed changes do not involve a significant reduction of safety.

3.2 APPLICABLE REGULATORY REQUIREMENTS/CRITERIA TVA has reviewed the NRC staffs model SE referenced in the Notice of Availability and concluded that the Regulatory Evaluation section is applicable to WBN Units 1 and 2.

WBN Units 1 and 2 commitments to regulatory guidance differs from that provided in the Regulatory Evaluation section in the model SE as described below.

The model SE refers to Revision 3 of Regulatory Guide (RG) 1 .32, "Criteria for Power Systems for Nuclear Power Plants. However, as described in FSAR Section 8.3.1.1, the design of the DG 125 VDC control power system for WBN Units 1 and 2 conforms to RG 1.32, Revision 2. The other portions of the electrical power system conform to RG 1.32, Revision 0.

The model SE refers to Revision 3 of RG 1.75, "Criteria for Independence of Electrical Safety Systems. However, as described in FSAR Section 8.1, RG 1.75 was issued after the Watts Bar design was complete. A description of how WBN Units 1 and 2 meet the intent of RG 1.75, Revision 0, is provided in FSAR Section 8.3.1.4.2.

TVA concluded these differences do not result in any needed changes for adoption of TSTF-500, Revision 2, at WBN Units 1 and 2 and do not affect the applicability of the NRC staff model SE.

4.0 ENVIRONMENTAL CONSIDERATION

The proposed TS change would change a requirement with respect to installation or use of a facility component located within the restricted area, as defined in 10 CFR Part 20, and would change an inspection or surveillance requirement. However, the proposed change does not involve (i) a significant hazards consideration, (ii) a significant change in the types or significant increase in the amounts of any effluent that may be released CNL-18-118 E1-10 of 11

Enclosure 1 Description and Assessment of Proposed Change offsite, or (iii) a significant increase in individual or cumulative occupational radiation exposure. Accordingly, the proposed TS change meets the eligibility criterion for categorical exclusion set forth in 10 CFR 51.22(c)(9). Therefore, pursuant to 10 CFR 51.22(b), no environmental impact statement or environmental assessment need be prepared in connection with the proposed TS change.

5.0 REFERENCES

1. Technical Specifications Task Force Traveler TSTF-500, Revision 2, "DC Electrical Rewrite-Update to TSTF-360" (ML092670242).

2. Federal Register (76 FR 54510): Notice of Availability of Proposed Models for Plant Specific Adoption of Technical Specifications Task Force Traveler TSTF-500, Revision 2, "DC Electrical Rewrite-Update to TSTF-360," dated September 1, 2011.

3. Federal Register (76 FR 69296): Notice of Availability of Proposed Models for Plant Specific Adoption of Technical Specifications Task Force Traveler TSTF-500, Revision 2, "DC Electrical Rewrite-Update to TSTF-360," dated November 8, 2011.

4. TVA Letter to NRC, "Technical Specification Change Request to Revise Completion Time for Inoperable Diesel Generator," dated November 30, 2009 (ML093640790).

5. NRC letter to TVA, "Watts Bar Nuclear Plant, Unit 1 - Issuance of Amendment Regarding the Completion Time for the Inoperable Emergency Diesel Generator(s)

(TAC No. ME2985)," dated July 6, 2010 (ML101390154).

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Enclosure 2 Markups of Technical Specification and Bases Changes CNL-18-118 E2-1

WBN Unit 1 Markups of Technical Specification and Bases CNL-18-118 E2-2

DC Sources - Operating 3.8.4 3.8 ELECTRICAL POWER SYSTEMS 3.8.4 DC Sources - Operating LCO 3.8.4 Four channels of The Train A and Train B vital DC electrical power subsystems and four Diesel Generator (DG) DC electrical power subsystems shall be OPERABLE.

NOTES------------------------------------------------

1. Vital Battery V may be substituted for any of the required vital batteries.

2. The C-S DG and its associated DC electrical power subsystem may be substituted for any of the required DGs and their associated DC electrical power subsystem.

APPLICABILITY: MODES 1, 2, 3, and 4.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One or two required vital A.1 Restore battery terminal 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months battery charger(s) on one voltage to greater than or subsystem inoperable. equal to the minimum established float voltage.

AND A.2 Verify battery float current Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months 2 amps.

AND A.3 Restore vital battery charger(s) 7 days to OPERABLE status.

AB. One vital DC electrical AB.1 Restore vital DC electrical 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months power subsystem power subsystem to inoperable for reasons OPERABLE status.

other than Condition A.

(continued)

Watts Bar-Unit 1 3.8-24

DC Sources - Operating 3.8.4 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME BC. Required Action and BC.1 Be in MODE 3. 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months Associated Completion Time of Condition A or B AND not met.

BC.2 Be in MODE 5. 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months D. One DG DC battery charger D.1 Restore DG battery terminal 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months inoperable. voltage to greater than or equal to the minimum established float voltage.

AND D.2 Verify battery float current Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months 1 amp.

AND D.3 Restore DG battery charger to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months OPERABLE status.

CE. One DG DC electrical CE.1 Restore DG DC electrical 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months power subsystem power subsystem to inoperable for reasons OPERABLE status.

other than Condition D.

DF. Required Action and DF.1 Declare associated DG Immediately associated Completion inoperable.

Time of Condition CD or E not met.

Watts Bar-Unit 1 3.8-25

DC Sources - Operating 3.8.4 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.4.1 Verify vital battery terminal voltage is 128 V (132 V 7 days for vital battery V) on float charge greater than or equal to the minimum established float voltage.

SR 3.8.4.2 Verify DG battery terminal voltage is 124 V on float 7 days charge greater than or equal to the minimum established float voltage.

SR 3.8.4.3 Verify for the vital batteries that the alternate feeder 7 days breakers to each required battery charger are open.

SR 3.8.4.4 Verify correct breaker alignment and indicated power 7 days availability for each DG 125 V DC distribution panel and associated battery charger.

(continued)

Watts Bar-Unit 1 3.8-26

DC Sources - Operating 3.8.4 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.4.5 Verify no visible corrosion at terminals and 92 days connectors for the vital batteries.

OR Verify connection resistance for the vital batteries is 80 E-6 ohm for inter-cell connections, 50 E-6 ohm for inter-rack connections, 120 E-6 ohm for inter-tier connections, and 50 E-6 ohm for terminal connections.

SR 3.8.4.6 Verify no visible corrosion at terminals and 92 days connectors for the DG batteries.

OR Verify connection resistance for the DG batteries is 80 E-6 ohm for inter-cell connections, 50 E-6 ohm for inter-tier connections, and 50 E-6 ohm for terminal connections.

SR 3.8.4.7 Verify battery cells, cell plates, and racks show no 12 months visual indication of physical damage or abnormal deterioration.

SR 3.8.4.8 Remove visible terminal corrosion and verify battery 12 months cell to cell and terminal connections are coated with anti-corrosion material.

(continued)

Watts Bar-Unit 1 3.8-27 Amendment 54

DC Sources - Operating 3.8.4 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.4.9 Verify connection resistance for the vital batteries is 12 months 80 E-6 ohm for inter-cell connections, 50 E-6 for inter-rack connections, 120 E-6 ohm for inter-tier connections, and 50 E-6 ohm for terminal connections.

SR 3.8.4.10 Verify connection resistance for the DG batteries is 12 months 80 E-6 ohm for inter-cell connections, 50 E-6 ohm for inter-tier connections, and 50 E-6 ohm for terminal connections.

SR 3.8.4.115 -------------------------------NOTE-------------------------------

This Surveillance is normally not performed in MODE 1, 2, 3, or 4. However, credit may be taken for unplanned events that satisfy this SR.

Verify each vital battery charger is capable of 18 months recharging its associated battery from a service or capacity discharge test while supplying normal loads supplies 200 amps at greater than or equal to the minimum established float voltage for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

OR Verify each vital battery charger is capable of operating for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months at current limit 220 - 250 amps can recharge the battery to the fully charged state within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months while supplying the largest combined demands of the various continuous steady state loads, after a battery discharge to the bounding design basis event discharge state.

(continued)

Watts Bar-Unit 1 3.8-28 Amendment 54

DC Sources - Operating 3.8.4 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.4.126 -------------------------------NOTE-------------------------------

Credit may be taken for unplanned events that satisfy this SR.

Verify each diesel generator DG battery charger is 18 months capable of recharging its associated battery from a service or capacity discharge test while supplying normal loads supplies 20 amps at greater than or equal to the minimum established float voltage for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

OR Verify each DG battery charger can recharge the battery to the fully charged state within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months while supplying the largest combined demands of the various continuous steady state loads, after a battery discharge to the bounding design basis event discharge state.

SR 3.8.4.137 ------------------------------NOTES------------------------------

1. The modified performance discharge test in SR 3.8.4.146.7 may be performed in lieu of the service test in SR 3.8.4.137 once per 60 months.

2. This Surveillance is not performed in MODE 1, 2, 3, or 4 for required vital batteries.

Credit may be taken for unplanned events that satisfy this SR.

Verify battery capacity is adequate to supply, and 18 months maintain in OPERABLE status, the required emergency loads and any connected nonsafety loads for the design duty cycle when subjected to a battery service test.

(continued)

Watts Bar-Unit 1 3.8-29 Amendment 12

DC Sources - Operating 3.8.4 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.4.14 ------------------------------NOTES------------------------------

This Surveillance is not performed in MODE 1, 2, 3, or 4 for required vital batteries. Credit may be taken for unplanned events that satisfy this SR.

Verify battery capacity is 80% of the manufacturer's 60 months rating when subjected to a performance discharge test or a modified performance discharge test. AND 12 months when battery shows degradation or has reached 85% of expected life with capacity < 100% of manufacturer's rating AND 24 months when battery has reached 85% of the expected life with capacity 100% of manufacturer's rating Watts Bar-Unit 1 3.8-30 Amendment 12

DC Sources - Shutdown 3.8.5 3.8 ELECTRICAL POWER SYSTEMS 3.8.5 DC Sources - Shutdown LCO 3.8.5 Vital DC and Diesel Generator (DG) DC electrical power subsystems shall be OPERABLE to support the DC electrical power distribution subsystem(s) required by LCO 3.8.10, "Distribution Systems - Shutdown" and to support the Diesel Generators (DGs) required by LCO 3.8.2, "AC Sources - Shutdown."

NOTES---------------------------------------------

1. Vital Battery V may be substituted for any of the required vital batteries.

2. The C-S DG and its associated DC electrical power subsystem may be substituted for any of the required DGs and their associated DC electrical power subsystems.

APPLICABILITY: MODES 5 and 6, During movement of irradiated fuel assemblies.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One or two required vital A.1 Restore battery terminal 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months battery charger(s) on one voltage to greater than or subsystem inoperable. equal to the minimum established float voltage.

AND AND The redundant subsystem vital battery and charger(s) A.2 Verify battery float current Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months OPERABLE. 2 amps.

AND A.3 Restore battery charger(s) to 7 days OPERABLE status.

(continued)

Watts Bar-Unit 1 3.8-30

DC Sources-Shutdown 3.8.5 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME AB. One or more required vital AB.1.1 Declare affected required Immediately DC electrical power feature(s) inoperable.

subsystems inoperable for reasons other than OR Condition A.

AB.2.1 Suspend CORE Immediately OR ALTERATIONS.

Required Actions and AND associated Completion Time of Condition A not AB.2.2 Suspend movement of Immediately met. irradiated fuel assemblies.

AND AB.2.3 Initiate action to suspend Immediately operations involving positive reactivity additions.

AND AB.2.4 Initiate action to restore Immediately required DC electrical power subsystems to OPERABLE status.

BC. One required DG DC BC.1 Declare associated DG Immediately electrical power subsystem inoperable.

inoperable.

Watts Bar-Unit 1 3.8-31

DC Sources-Shutdown 3.8.5 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.5.1 --------------------------------NOTE-----------------------------

The following SRs are not required to be performed:

SR 3.8.4.115, SR 3.8.4.126, and SR 3.8.4.137, and SR 3.8.4.14.

For DC sources required to be OPERABLE, the In accordance with following SRs are applicable: applicable SRs SR 3.8.4.1 SR 3.8.4.6 SR 3.8.4.11 SR 3.8.4.2 SR 3.8.4.7 SR 3.8.4.12 SR 3.8.4.3 SR 3.8.4.8 SR 3.8.4.13 SR 3.8.4.4 SR 3.8.4.9 SR 3.8.4.14 SR 3.8.4.5 SR 3.8.4.10 Watts Bar-Unit 1 3.8-32

Battery Cell Parameters 3.8.6 3.8 ELECTRICAL POWER SYSTEMS 3.8.6 Battery Cell Parameters LCO 3.8.6 Battery cell parameters for Train A and Train B electrical power subsystem 125 V vital batteries and 125 V diesel generator (DG) batteries shall be within the limits of Table 3.8.6-1.

APPLICABILITY: When associated DC electrical power subsystems and DGs are required to be OPERABLE.

ACTIONS

NOTE---------------------------------------------------------------

Separate Condition entry is allowed for each battery bank.

CONDITION REQUIRED ACTION COMPLETION TIME A. One or more batteries with A.1 Verify pilot cells electrolyte 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months one or more battery cell level and float voltage meet parameters not within Table 3.8.6-1 Category C Category A or B limits. limits.

AND A.2 Verify battery cell parameters 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months meet Table 3.8.6-1 Category C limits. AND Once per 7 days thereafter AND A.3 Restore battery cell 31 days parameters to Category A and B limits of Table 3.8.6-1.

(continued)

Watts Bar-Unit 1 3.8-33

Battery Cell Parameters 3.8.6 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One or two required vital A.1 Perform SR 3.8.4.1. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months battery(ies) on one subsystem with one or AND more battery cells float voltage < 2.07 V. A.2 Perform SR 3.8.6.1. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months AND A.3 Restore affected cell voltage 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 2.07 V.

B. One or two required vital B.1 Perform SR 3.8.4.1. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months battery(ies) on one subsystem with float AND current > 2 amps.

B.2 Restore vital battery float 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months current to 2 amps.

C. One DG battery with one C.1 Perform SR 3.8.4.2. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months or more battery cells float voltage < 2.07 V. AND C.2 Perform SR 3.8.6.2. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months AND C.3 Restore affected cell voltage 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 2.07 V.

D. One DG battery with float D.1 Perform SR 3.8.4.2. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months current > 1 amp.

AND D.2 Restore vital battery float 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months current to 1 amp.

(continued)

Watts Bar-Unit 1 3.8-34

Battery Cell Parameters 3.8.6 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME

NOTE--------------------- ---------------------NOTE----------------------

Required Action E.2 shall be Required Actions E.1 and E.2 are only completed if electrolyte level was applicable if electrolyte level was below below the top of plates. the top of plates.

E. One or two required vital E.1 Restore electrolyte level to 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months battery(ies) on one above top of plates.

subsystem with one or more cells electrolyte level AND less than minimum established design limits. E.2 Verify no evidence of leakage. 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months OR AND One DG battery with one E.3 Restore electrolyte level to 31 days or more cells electrolyte greater than or equal to level less than minimum minimum established design established design limits. limits.

F. One or two required vital F.1 Restore battery pilot cell 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months battery(ies) on one temperature to greater than or subsystem with pilot cell equal to minimum established electrolyte temperature design limits.

less than minimum established design limits.

OR One DG battery with pilot cell electrolyte temperature less than minimum established design limits.

(continued)

Watts Bar-Unit 1 3.8-35

Battery Cell Parameters 3.8.6 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME G. One or more batteries in G.1 Restore battery parameters to 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months redundant subsystems with within limits.

battery parameters not within limits.

OR More than one DG battery with battery parameters not within limits.

BH. Required Action and BH.1 Declare associated battery Immediately associated Completion inoperable.

Time of Condition A, B, C, D, E, F, or G not met.

OR One or two required vital battery(ies) on one subsystem with one or more battery cells float voltage < 2.07 V and float current > 2 amps.

OR One DG battery with one or more battery cells float voltage < 2.07 V and float current > 1 amp.

One or more batteries with average electrolyte temperature of the representative cells < 60F for vital batteries and <

50F for DG batteries.

OR One or more batteries with one or more battery cell parameters not within Category C values.

Watts Bar-Unit 1 3.8-36

Battery Cell Parameters 3.8.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.6.1 Verify battery cell parameters meet Table 3.8.6-1 7 days Category A limits.

SR 3.8.6.2 Verify battery cell parameters meet Table 3.8.6-1 92 days Category B limits.

AND Once within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after a battery discharge < 110 V for vital batteries (113.5 V for vital battery V) or 106.5 V for DG batteries AND Once within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after a battery overcharge > 150 V for vital batteries (155 V for vital battery V) or 145 V for DG batteries SR 3.8.6.3 Verify average electrolyte temperature of 92 days representative cells is 60F for vital batteries and 50F for the DG batteries.

Insert Surveillance Requirements from next page.

Watts Bar-Unit 1 3.8-37

Insert the following Surveillance Requirements for LCO 3.8.6:

SURVEILLANCE FREQUENCY SR 3.8.6.1 ------------------------------NOTE--------------------------------

Not required to be met when vital battery terminal voltage is less than the minimum established float voltage of SR 3.8.4.1.

Verify each vital battery float current is 2 amps. 7 days SR 3.8.6.2 ------------------------------NOTE--------------------------------

Not required to be met when DG battery terminal voltage is less than the minimum established float voltage of SR 3.8.4.2.

Verify each DG battery float current is 1 amp. 7 days SR 3.8.6.3 Verify each required vital battery and each DG 31 days battery pilot cell float voltage is 2.07 V.

SR 3.8.6.4 Verify each required vital battery and each DG 31 days battery connected cell electrolyte level is greater than or equal to minimum established design limits.

SR 3.8.6.5 Verify each required vital battery and each DG 31 days battery pilot cell temperature is greater than or equal to minimum established design limits.

SR 3.8.6.6 Verify each required vital battery and each DG 92 days battery connected cell float voltage is 2.07 V.

SURVEILLANCE FREQUENCY SR 3.8.6.7 ------------------------------NOTES------------------------------

This Surveillance is not performed in MODE 1, 2, 3, or 4 for required vital batteries. Credit may be taken for unplanned events that satisfy this SR.

Verify battery capacity is 80% of the manufacturer's 60 months rating when subjected to a performance discharge test or a modified performance discharge test. AND 12 months when battery shows degradation or has reached 85% of expected life with capacity < 100% of manufacturer's rating AND 24 months when battery has reached 85% of the expected life with capacity 100% of manufacturer's rating

Battery Cell Parameters 3.8.6 Table 3.8.6-1 (page 1 of 1)

Battery Cell Parameters Requirements CATEGORY A: CATEGORY B: CATEGORY C:

PARAMETER LIMITS FOR EACH LIMITS FOR EACH ALLOWABLE LIMIT DESIGNATED PILOT CONNECTED CELL FOR EACH CELL CONNECTED CELL Electrolyte Level > Minimum level > Minimum level Above top of plates, indication mark, and indication mark, and and not overflowing 1/4 inch above 1/4 inch above maximum level maximum level indication mark (a) indication mark (a)

Float Voltage 2.13 V 2.13 V > 2.07 V Specific Gravity (b)(c) 1.200 1.195 Not more than 0.020 below average of all AND connected cells Average of all AND connected cells

> 1.205 Average of all connected cells 1.195 (a) It is acceptable for the electrolyte level to temporarily increase above the specified maximum level during equalizing charges provided it is not overflowing.

(b) Corrected for electrolyte temperature and level. Level correction is not required, however, when battery charging is < 2 amps when on float charge for vital batteries and < 1.0 amp for DG batteries.

(c) A battery charging current of < 2 amps when on float charge for vital batteries and < 1.0 amp for DG batteries is acceptable for meeting specific gravity limits following a battery recharge, for a maximum of 31 days. When charging current is used to satisfy specific gravity requirements, specific gravity of each connected cell shall be measured prior to expiration of the 31 day allowance.

Watts Bar-Unit 1 3.8-38

Procedures, Programs, and Manuals 5.7 5.7 Procedures, Programs, and Manuals 5.7.2.20 Control Room Envelope Habitability Program (continued)

d. Measurement, at designated locations, of the CRE pressure relative to all external areas adjacent to the CRE boundary during the pressurization mode of operation by one train of the CREVS, operating at the flow rate defined in the Ventilation Filter Testing Program (VFTP), at a Frequency of 18 months on a STAGGERED TEST BASIS. The results shall be trended and used as part of the 18 month assessment of the CRE boundary.

e. The quantitative limits on unfiltered air inleakage into the CRE. These limits shall be stated in a manner to allow direct comparison to the unfiltered air inleakage measured by the testing described in paragraph c. The unfiltered air inleakage limit for radiological challenges is the inleakage flow rate assumed in the licensing basis analyses of DBA consequences. Unfiltered air inleakage limits for hazardous chemicals must ensure that exposure of CRE occupants to these hazards will be within the assumptions in the licensing basis.

f. The provisions of SR 3.0.2 are applicable to the frequencies for assessing CRE habitability, determining CRE unfiltered inleakage, and measuring CRE pressure and assessing the CRE boundary as required by paragraphs c and d, respectively.

Note: The addition of TS 5.7.2.21, Spent Fuel Storage Rack Neutron Absorber Monitoring Program, has been proposed per TVA letter CNL-17-144, dated December 20, 2017. Therefore, the proposed addition of the Battery Monitoring and Maintenance Program is numbered TS 5.7.2.22, to reflect the anticipated approval of the license amendment request associated with TVA letter CNL-17-144.

Insert TS 5.7.2.22, Battery Monitoring and Maintenance Program Watts Bar-Unit 1 5.0-25a Amendment 70, 78

INSERT 5.7.2.22 Battery Monitoring and Maintenance Program This Program provides controls for battery restoration and maintenance. The program shall be in accordance with IEEE Standard (Std) 450-2002, "IEEE Recommended Practice for Maintenance, Testing, and Replacement of Vented Lead-Acid Batteries for Stationary Applications," as endorsed by Regulatory Guide 1.129, Revision 2 (RG), with RG exceptions and program provisions as identified below:

a. The program allows the following RG 1.129, Revision 2 exceptions:

1. Battery temperature correction may be performed before or after conducting discharge tests.

2. RG 1.129, Regulatory Position 1, Subsection 2, "References," is not applicable to this program.

3. In lieu of RG 1.129, Regulatory Position 2, Subsection 5.2, "Inspections," the following shall be used: "Where reference is made to the pilot cell, pilot cell selection shall be based on the lowest voltage cell in the battery.

4. In Regulatory Guide 1.129, Regulatory Position 3, Subsection 5.4.1, "State of Charge Indicator," the following statements in paragraph (d) may be omitted: "When it has been recorded that the charging current has stabilized at the charging voltage for three consecutive hourly measurements, the battery is near full charge. These measurements shall be made after the initially high charging current decreases sharply and the battery voltage rises to approach the charger output voltage."

5. In lieu of RG 1.129, Regulatory Position 7, Subsection 7.6, "Restoration", the following may be used: "Following the test, record the float voltage of each cell of the string."

b. The program shall include the following provisions:

1. Actions to restore battery cells with float voltage < 2.13 V;

2. Actions to determine whether the float voltage of the remaining battery cells is 2.13 V when the float voltage of a battery cell has been found to be < 2.13 V;

3. Actions to equalize and test battery cells that had been discovered with electrolyte level below the top of the plates;

4. Limits on average electrolyte temperature, battery connection resistance, and battery terminal voltage; and

5. A requirement to obtain specific gravity readings of all cells at each discharge test, consistent with manufacturer recommendations.

DC Sources-Operating B 3.8.4 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.4 DC Sources - Operating BASES BACKGROUND The station DC electrical power system provides the AC emergency power system with control power. It also provides both motive and control power to selected safety related equipment and preferred AC vital bus power (via inverters). As required by 10 CFR 50, Appendix A, GDC 17 (Ref. 1), the DC electrical power system is designed to have sufficient independence, redundancy, and testability to perform its safety functions, assuming a single failure. The DC electrical power system also conforms to the recommendations of Regulatory Guide 1.6 (Ref. 2) and IEEE-308 (Ref. 3).

125 V Vital DC Electrical Power Subsystem The vital 125 VDC electrical power system is a Class IE system whose safety function is to provide control power for engineered safety features equipment, emergency lighting, vital inverters, and other safety-related DC powered equipment for the entire unit. The system capacity is sufficient to supply these loads and any connected nonsafety loads during normal operation and to permit safe shutdown and isolation of the reactor for the "loss of all AC power" condition. The system is designed to perform its safety function subject to a single failure.

The 125V DC vital power system is composed of the four redundant channels (Channels I and III are associated with Train A and Channels II and IV are associated with Train B) and consists of four lead-acid-calcium batteries, eight battery chargers (including two pairs of spare chargers), four distribution boards, battery racks, and the required cabling, instrumentation and protective features.

Each channel is electrically and physically independent from the equipment of all other channels so that a single failure in one channel will not cause a failure in another channel. Each channel consists of a battery charger which supplies normal DC power, a battery for emergency DC power, and a battery board which facilitates load grouping and provides circuit protection. These four channels are used to provide emergency power to the 120V AC vital power system which furnishes control power to the reactor protection system. No automatic connections are used between the four redundant channels.

Battery boards I, II, III, and IV have a charger normally connected to them and also have manual access to a spare (backup) charger for use upon loss of the normal charger.

(continued)

Watts Bar-Unit 1 B 3.8-54 Revision 105

DC Sources-Operating B 3.8.4 BASES BACKGROUND 125 V Vital DC Electrical Power Subsystem (continued)

Additionally, battery boards I, II, III, and IV have manual access to the fifth vital battery system. The fifth 125V DC Vital Battery System is intended to serve as a replacement for any one of the four 125V DC vital batteries during their testing, maintenance, and outages with no loss of system reliability under any mode of operation.

Each of the vital DC electrical power subsystems provide the control power for its associated Class 1E AC power load group, 6.9 kV switchgear, and 480 V load centers. The vital DC electrical power subsystems also provide DC electrical power to the inverters, which in turn power the AC vital buses. Additionally, they power the emergency DC lighting system.

The vital DC power distribution system is described in more detail in Bases for LCO 3.8.9, "Distribution System - Operating," and LCO 3.8.10, "Distribution Systems - Shutdown."

Each vital battery has adequate storage capacity to carry the required load continuously for at least 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months in the event of a loss of all AC power (station blackout) without an accident or for 30 minutes with an accident considering a single failure. Load shedding of nonrequired loads will be performed to achieve the required coping duration for station blackout conditions.

Each 125 VDC vital battery is separately housed in a ventilated room apart from its charger and distribution centers, except for Vital Battery V. Each subsystem is located in an area separated physically and electrically from the other subsystem to ensure that a single failure in one subsystem does not cause a failure in a redundant subsystem. There is no sharing between redundant Class 1E subsystems, such as batteries, battery chargers, or distribution panels.

Each battery has adequate storage capacity to meet the duty cycle(s) discussed in the FSAR, Chapter 8 (Ref 4). The battery is designed with additional capacity above that required by the design duty cycle to allow for temperature variations and other factors.

The batteries for the vital DC electrical power subsystems are sized to produce required capacity at 80% of nameplate rating, corresponding to warranted capacity at end of life cycles, derated for minimum ambient temperature and the (continued)

Watts Bar-Unit 1 B 3.8-55

DC Sources-Operating B 3.8.4 BASES BACKGROUND 125 V Vital DC Electrical Power Subsystem (continued) 100% design demand. The minimum design voltage limit is 105 V.The voltage limit is 2.13 V per cell, which corresponds to a total minimum voltage output of 128 V per battery (132 V for Vital Battery V). The criteria for sizing large lead storage batteries are defined in IEEE-485 (Ref. 5).

The battery cells are of flooded lead acid construction with a nominal specific gravity of 1.215. This specific gravity corresponds to an open circuit battery voltage of approximately 120 V for a 60 cell battery (i.e., cell voltage of 2.063 volts per cell (Vpc)). The open circuit voltage is the voltage maintained when there is no charging or discharging. Optimal long term performance however, is obtained by maintaining a float voltage 2.20 to 2.25 Vpc. This provides adequate over-potential, which limits the formation of lead sulfate and self discharge. The nominal float voltage of 2.22 Vpc corresponds to a total float voltage output of 132 V for a 60 cell battery as discussed in the FSAR, Chapter 8 (Ref. 4).

Each Vital DC electrical power subsystem battery charger has ample power output capacity for the steady state operation of connected loads required during normal operation, while at the same time maintaining its battery bank fully charged. Each battery charger also has sufficient excess capacity to restore the battery bank from the design minimum charge to its fully charged state within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months (with accident loads being supplied) following a 30 minute AC power outage and in approximately 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months (while supplying normal steady state loads following a 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months AC power outage), (Ref. 65).

The battery charger is normally in the float-charge mode. Float-charge is the condition in which the charger is supplying the connected loads and the battery cells are receiving adequate current to optimally charge the battery. This assures the internal losses of a battery are overcome and the battery is maintained in a fully charged state.

When desired, the charger can be placed in the equalize mode. The equalize mode is at a higher voltage than the float mode and charging current is correspondingly higher. The battery charger is operated in the equalize mode after a battery discharge or for routine maintenance. Following a battery discharge, the battery recharge characteristic accepts current at the current limit of the battery charger (if the discharge was significant, e.g., following a battery service test) until the battery terminal voltage approaches the charger voltage setpoint. Charging current then reduces exponentially during the remainder of the recharge cycle. Lead-calcium batteries have recharge efficiencies of greater than 95%, so once at least 105% of the ampere-hours discharged have been returned, the battery capacity would be restored to the same condition as it was prior to the discharge. This can be monitored by direct observation of the exponentially decaying charging current or by evaluating the amp-hours discharged from the battery and amp-hours returned to the battery.

(continued)

Watts Bar-Unit 1 B 3.8-56 Revision 113

DC Sources-Operating B 3.8.4 BASES BACKGROUND 125 V Diesel Generator (DG) DC Electrical Power Subsystem (continued)

Control power for the DGs is provided by five DG battery systems, one per DG.

Each system is comprised of a battery, a dual battery charger assembly, distribution center, cabling, and cable ways. The DG 125V DC control power and field-flash circuits have power supplied from their respective 125V distribution panel. The normal supply of DC current is from the associated charger. The battery provides control and field-flash power when the charger is unavailable. The charger supplies the normal DC loads, maintains the battery in a fully charged condition, and recharges (480V AC available) the battery while supplying the required loads regardless of the status of the unit. The batteries are physically and electrically independent. The battery has sufficient capacity when fully charged to supply required loads for a minimum of 30 minutes following a loss of normal power. Each battery is normally required to supply loads during the time interval between loss of normal feed to its charger and the receipt of emergency power to the charger from its respective DG.

APPLICABLE The initial conditions of Design Basis Accident (DBA) and SAFETY ANALYSES transient analyses in the FSAR, Section 6 (Ref. 76), and in the FSAR, Section 15 (Ref. 76), assume that Engineered Safety Feature (ESF) systems are OPERABLE. The vital DC electrical power system provides normal and emergency DC electrical power for the emergency auxiliaries, and control and switching during all power for the emergency auxiliaries, and control and switching during all MODES of operation. The DG battery systems provide DC power for the DGs.

The OPERABILITY of the DC sources is consistent with the initial assumptions of the accident analyses and is based upon meeting the design basis of the plant.

This includes maintaining the DC sources OPERABLE during accident conditions in the event of:

a. An assumed loss of all offsite AC power or all onsite AC power; and

b. A worst case single failure.

The DC sources satisfy Criterion 3 of the NRC Policy Statement.

(continued)

Watts Bar-Unit 1 B 3.8-57 Revision 113

DC Sources-Operating B 3.8.4 BASES LCO Four Two 125V vital DC electrical power subsystems (Train A and Train B), each vital subsystem consisting of two channels. Each channel consisting of a battery bank, associated battery charger and the corresponding control equipment and interconnecting cabling supplying power to the associated DC bus within the channel; and four DG DC electrical power subsystems each consisting of a battery, a dual battery charger assembly, and the corresponding control equipment and interconnecting cabling are required to be OPERABLE to ensure the availability of the required power to shut down the reactor and maintain it in a safe condition after an anticipated operational occurrence (A00) or a postulated DBA. Loss of any DC electrical power subsystem does not prevent the minimum safety function from being performed (Ref. 4).

An OPERABLE vital DC electrical power subsystem requires all required batteries and respective chargers to be operating and connected to the associated DC buses.

The LCO is modified by two a Notes. The Note 1 indicates that Vital Battery V may be substituted for any of the required vital batteries. However, the fifth battery cannot be declared OPERABLE until it is connected electrically in place of another battery and it has satisfied applicable Surveillance Requirements.

Note 2 has been added to indicate that the C-S DG and its associated DC subsystem may be substituted for any of the required DGs. However, the C-S DG and its associated DC subsystem cannot be declared OPERABLE until it is connected electrically in place of another DG, and it has satisfied applicable Surveillance Requirements.

APPLICABILITY The four vital DC electrical power sources and four DG DC electrical power sources are required to be OPERABLE in MODES 1, 2, 3, and 4 to ensure safe plant operation and to ensure that:

a. Acceptable fuel design limits and reactor coolant pressure boundary limits are not exceeded as a result of AOs or abnormal transients; and

b. Adequate core cooling is provided, and containment integrity and other vital functions are maintained in the event of a postulated DBA.

The DC electrical power requirements for MODES 5 and 6 are addressed in the Bases for LCO 3.8.5, "DC Sources - Shutdown."

(continued)

Watts Bar-Unit 1 B 3.8-58

DC Sources-Operating B 3.8.4 BASES ACTIONS A.1, A.2, and A.3 Condition A represents one vital DC subsystem with one or two battery chargers inoperable (e.g., the voltage limit of SR 3.8.4.1 is not maintained). The ACTIONS provide a tiered response that focuses on returning the battery to the fully charged state and restoring a fully qualified charger to OPERABLE status in a reasonable time period. Required Action A.1 requires that the battery terminal voltage be restored to greater than or equal to the minimum established float voltage within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . This time provides for returning the inoperable charger to OPERABLE status or providing an alternate means of restoring battery terminal voltage to greater than or equal to the minimum established float voltage.

Restoring the battery terminal voltage to greater than or equal to the minimum established float voltage provides good assurance that, within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , the battery will be restored to its fully charged condition (Required Action A.2) from any discharge that might have occurred due to the charger inoperability.

A discharged battery having terminal voltage of at least the minimum established float voltage indicates that the battery is on the exponential charging current portion (the second part) of its recharge cycle. The time to return a battery to its fully charged state under this condition is simply a function of the amount of the previous discharge and the recharge characteristic of the battery. Thus there is good assurance of fully recharging the battery within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , avoiding a premature shutdown with its own attendant risk.

If established battery terminal float voltage cannot be restored to greater than or equal to the minimum established float voltage within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months , and the charger is not operating in the current-limiting mode, a faulty charger is indicated. A faulty charger that is incapable of maintaining established battery terminal float voltage does not provide assurance that it can revert to and operate properly in the current limit mode that is necessary during the recovery period following a battery discharge event that the DC system is designed for.

If the charger is operating in the current limit mode after 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months that is an indication that the battery is partially discharged and its capacity margins will be reduced. The time to return the battery to its fully charged condition in this case is a function of the battery charger capacity, the amount of loads on the associated DC system, the amount of the previous discharge, and the recharge characteristic of the battery. The charge time can be extensive, and there is not adequate assurance that it can be recharged within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months (Required Action A.2).

Required Action A.2 requires that the battery float current be verified as less than or equal to 2 amps. This indicates that, if the battery had been discharged as the result of the inoperable battery charger, it is now fully capable of supplying the maximum expected load requirement. The 2 amp value is based on returning the battery to 98% charge and assumes a 2% design margin for the battery. If at the (continued)

Watts Bar-Unit 1 B 3.8-59

DC Sources-Operating B 3.8.4 BASES ACTIONS A.1, A.2, and A.3 (continued) expiration of the initial 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months period the battery float current is not less than or equal to 2 amps this indicates there may be additional battery problems and the battery must be declared inoperable.

Required Action A.3 limits the restoration time for the inoperable battery charger to 7 days. This action is applicable if an alternate means of restoring battery terminal voltage to greater than or equal to the minimum established float voltage has been used (e.g., balance of plant non-Class 1E battery charger). The 7 day Completion Time reflects a reasonable time to effect restoration of the qualified battery charger to OPERABLE status.

AB.1 Condition AB represents one vital channel DC electrical power subsystem with a loss of ability to completely respond to an event, and a potential loss of ability to remain energized during normal operation. It is, therefore, imperative that the operator's attention focus on stabilizing the plant, minimizing the potential for complete loss of DC power to the affected train subsystem. The 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months limit is consistent with the allowed time for an inoperable DC distribution subsystem train.

If one of the required vital DC electrical power subsystems is inoperable for reasons other than Condition A (e.g., inoperable battery, inoperable battery charger(s), or inoperable battery charger and associated inoperable battery), the remaining vital DC electrical power subsystem has the capacity to support a safe shutdown and to mitigate an accident condition. Since a subsequent worst case single failure of the OPERABLE subsystem would could, however, result in a situation where the ability of the 125V DC electrical power subsystem to support its required ESF function is not assured, the loss of the minimum necessary vital DC electrical power subsystems to mitigate a worst-case accident, continued power operation should not exceed 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . The 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months Completion Time is based on Regulatory Guide 1.93 (Ref. 87) and reflects a reasonable time to assess plant status as a function of the inoperable vital DC electrical power subsystem and, if the vital DC electrical power subsystem is not restored to OPERABLE status, to prepare to effect an orderly and safe plant shutdown.

B.1 and B.2C,1 and C.2 If the inoperable vital DC electrical power subsystem cannot be restored to OPERABLE status within the required Completion Time, the plant must be brought to a MODE in which the LCO does not apply. To achieve this status, the plant must be brought to at least MODE 3 within 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months and to MODE 5 within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months . The allowed Completion Times are reasonable, based on operating experience, to reach the required plant conditions from full power conditions in an orderly manner and without challenging plant systems. The Completion Time (continued)

Watts Bar-Unit 1 B 3.8-60

DC Sources-Operating B 3.8.4 BASES ACTIONS B.1 and B.2C,1 and C.2 (continued)

(continued) to bring the plant to MODE 5 is consistent with the time required in Regulatory Guide 1.93 (Ref. 87).

D.1, D.2, and D.3 Condition D represents one DG DC subsystem with one battery charger inoperable (e.g., the voltage limit of SR 3.8.4.1 is not maintained). The ACTIONS provide a tiered response that focuses on returning the battery to the fully charged state and restoring a fully qualified charger to OPERABLE status in a reasonable time period. Required Action D.1 requires that the battery terminal voltage be restored to greater than or equal to the minimum established float voltage within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . This time provides for returning the inoperable charger to OPERABLE status or providing an alternate means of restoring battery terminal voltage to greater than or equal to the minimum established float voltage.

Restoring the battery terminal voltage to greater than or equal to the minimum established float voltage provides good assurance that, within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , the battery will be restored to its fully charged condition (Required Action D.2) from any discharge that might have occurred due to the charger inoperability.

A discharged battery having terminal voltage of at least the minimum established float voltage indicates that the battery is on the exponential charging current portion (the second part) of its recharge cycle. The time to return a battery to its fully charged state under this condition is simply a function of the amount of the previous discharge and the recharge characteristic of the battery. Thus there is good assurance of fully recharging the battery within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , avoiding a premature shutdown with its own attendant risk.

If established battery terminal float voltage cannot be restored to greater than or equal to the minimum established float voltage within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months , and the charger is not operating in the current-limiting mode, a faulty charger is indicated. A faulty charger that is incapable of maintaining established battery terminal float voltage does not provide assurance that it can revert to and operate properly in the current limit mode that is necessary during the recovery period following a battery discharge event that the DG DC system is designed for.

If the charger is operating in the current limit mode after 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months that is an indication that the battery is partially discharged and its capacity margins will be reduced. The time to return the battery to its fully charged condition in this case is a function of the battery charger capacity, the amount of loads on the associated DC system, the amount of the previous discharge, and the recharge characteristic of the battery. The charge time can be extensive, and there is not adequate assurance that it can be recharged within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months (Required Action D.2).

(continued)

Watts Bar-Unit 1 B 3.8-61

DC Sources-Operating B 3.8.4 BASES ACTIONS D.1, D.2, and D.3 (continued)

Required Action D.2 requires that the battery float current be verified as less than or equal to 1 amp. This indicates that, if the battery had been discharged as the result of the inoperable battery charger, it is now fully capable of supplying the maximum expected load requirement. The 1 amp value is based on returning the battery to 98% charge and assumes a 2% design margin for the battery. If at the expiration of the initial 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months period the battery float current is not less than or equal to 1 amp this indicates there may be additional battery problems and the battery must be declared inoperable.

Required Action D.3 limits the restoration time for the inoperable battery charger to 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months . The 72 hour8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months Completion Time reflects a reasonable time to effect restoration of the qualified battery charger to OPERABLE status.

C.1E.1 Condition CE represents one DG with a loss of ability to completely respond to an event. Since a subsequent single failure on the opposite train could result in a situation where the required ESF function is not assured, continued power operation should not exceed 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . The 2 hour2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months time limit is consistent with the allowed time for an inoperable vital DC electrical power subsystem.

D.1F.1 If the DG DC electrical power subsystem cannot be restored to OPERABLE status in the associated Completion Time, the associated DG may be incapable of performing its intended function and must be immediately declared inoperable.

This declaration also requires entry into applicable Conditions and Required Actions for an inoperable DG, LCO 3.8.1, "AC Sources-Operating."

(continued)

Watts Bar-Unit 1 B 3.8-62

DC Sources-Operating B 3.8.4 BASES (continued)

SURVEILLANCE SR 3.8.4.1 and SR 3.8.4.2 REQUIREMENTS Verifying battery terminal voltage while on float charge for the batteries helps to ensure the effectiveness of the battery chargers, which support the ability of the batteries to perform their intended function charging system and the ability of the batteries to perform their intended function. Float charge is the condition in which the charger is supplying the continuous charge required to overcome the internal losses of a battery (or battery cell) and maintain the battery (or a battery cell) in a fully charged state while supplying the continuous steady state loads of the associated DC subsystem. On float charge, battery cells will receive adequate current to optimally charge the battery. The voltage requirements are based on the critical nominal design voltage of the battery and are consistent with the initial voltages assumed in the battery sizing calculations minimum float voltage established by the battery manufacturer (2.20 Vpc times the number of connected cells or 132 V at the battery terminals for a 60 cell vital battery; 127.6 V at the battery terminals for a 58 cell DG battery). This voltage maintains the battery plates in a condition that supports maintaining the grid life. The 7 day Frequency is consistent with manufacturer recommendations and IEEE-450 (Ref. 9).

SR 3.8.4.3 Verifying that for the vital batteries that the alternate feeder breakers to each required battery charger is open ensures that independence between the power trains is maintained. The 7-day Frequency is based on engineering judgement, is consistent with procedural controls governing breaker operation, and ensures correct breaker position.

SR 3.8.4.4 This SR demonstrates that the DG 125V DC distribution panel and associated charger are functioning properly, with all required circuit breakers closed and buses energized from normal power. The 7 day Frequency takes into account the redundant DG capability and other indications available in the control room that will alert the operator to system malfunctions.

SR 3.8.4.5 and SR 3.8.4.6 Visual inspection to detect corrosion of the battery cells and connections, or measurement of the resistance of each intercell, interrack, intertier, and terminal connection, provides an indication of physical damage or abnormal deterioration that could potentially degrade battery performance.

(continued)

Watts Bar-Unit 1 B 3.8-63

DC Sources-Operating B 3.8.4 BASES SURVEILLANCE SR 3.8.4.5 and SR 3.8.4.6 (continued)

REQUIREMENTS The limits established for this SR must be no more than 20% above the resistance as measured during installation, or not above the ceiling value established by the manufacturer.

The Surveillance Frequency for these inspections, which can detect conditions that can cause power losses due to resistance heating, is 92 days. This Frequency is considered acceptable based on operating experience related to detecting corrosion trends.

SR 3.8.4.7 Visual inspection of the battery cells, cell plates, and battery racks provides an indication of physical damage or abnormal deterioration that could potentially degrade battery performance.

The 12 month Frequency for this SR is consistent with IEEE-450 (Ref. 9), which recommends detailed visual inspection of cell condition and rack integrity on a yearly basis.

SR 3.8.4.8, SR 3.8.4.9 and SR 3.8.4.10 Visual inspection and resistance measurements of intercell, interrack, intertier, and terminal connections provide an indication of physical damage or abnormal deterioration that could indicate degraded battery condition. The anticorrosion material is used to help ensure good electrical connections and to reduce terminal deterioration. The visual inspection for corrosion is not intended to require removal of and inspection under each terminal connection. The removal of visible corrosion is a preventive maintenance SR. The presence of visible corrosion does not necessarily represent a failure of this SR provided visible corrosion is removed during performance of SR 3.8.4.8. For the purposes of trending, inter-cell (vital and DG batteries) and inter-tier (vital and DG batteries) connections are measured from battery post to battery post. Inter-rack (vital batteries), inter-tier (DG Batteries), and terminal connections (vital and DG batteries) are measured from terminal lug to battery post.

(continued)

Watts Bar-Unit 1 B 3.8-61 Revision 56, 69 Amendment 54

DC Sources-Operating B 3.8.4 BASES SURVEILLANCE SR 3.8.4.8, SR 3.8.4.9 and SR 3.8.4.10 (continued)

REQUIREMENTS The connection resistance limits for SR 3.8.4.9 and SR 3.8.4.10 shall be no more than 20% above the resistance as measured during installation, or not above the ceiling value established by the manufacturer.

The Surveillance Frequencies of 12 months is consistent with IEEE-450 (Ref. 9),

which recommends cell to cell and terminal connection resistance measurement on a yearly basis.

SR 3.8.4.115 This SR requires that each vital battery charger be capable of recharging its associated battery from a capacity or service discharge test while supplying normal loads, or alternatively, operating at current limit for a minimum of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months at a nominal 125 VDC. These requirements are based on verifies the design capacity of the vital battery chargers (Ref. 4) and their performance characteristic of current limit operation for a substantial portion of the recharge period. Battery charger output current is limited to 110% - 125% of the 200 amp rated output.

Recharging the battery or testing for a minimum of 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months is sufficient to verify the output capability of the charger can be sustained, that current limit adjustments are properly set and that protective devices will not inhibit performance at current limit settings. According to Regulatory Guide 1.32 (Ref. 65), the battery charger supply is required recommended to be based on the largest combined demands of the various steady state loads and the charging capacity to restore the battery from the design minimum charge state to the fully charged state, irrespective of the status of the plant during these demand occurrences. Verifying the capability of the charger to operate in a sustained current limit condition The minimum required amperes and duration ensures that these requirements can be satisfied.

This SR provides two options. One option requires that each battery charger be capable of supplying 200 amps at the minimum established float voltage (132 V DC) for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months . The ampere requirements are based on the output rating of the chargers. The voltage requirements are based on the charger voltage level after a response to a loss of AC power.

The other option requires that each vital battery charger be capable of recharging the battery after a service test coincident with supplying the largest coincident demands of the various continuous steady state loads (irrespective of the status of the plant during which these demands occur). This level of loading may not normally be available following the battery service test and will need to be supplemented with additional loads. The duration for this test may be longer than the charger sizing criteria since the battery recharge is affected by float voltage, temperature, and the exponential decay in charging current. The battery is recharged when the measured charging current is 2 amps.

(continued)

Watts Bar-Unit 1 B 3.8-62

DC Sources-Operating B 3.8.4 BASES SURVEILLANCE SR 3.8.4.115 (continued)

REQUIREMENTS The Surveillance Frequency is acceptable, given the plant conditions required to perform the test and the other administrative controls existing to ensure adequate charger performance during these 18 month intervals. In addition, this Frequency is intended to be consistent with expected fuel cycle lengths.

This SR is modified by a Note. The reason for the Note is that performing the Surveillance may perturb the electrical distribution system and challenge safety systems. This Surveillance is normally performed during MODES 5 and 6 since it would require the DC electrical power subsystem to be inoperable during performance of the test. However, this Surveillance may be performed in MODES 1, 2, 3, or 4 provided the Vital Battery V is substituted in accordance with LCO Note 1. Credit may be taken for unplanned events that satisfy this SR. Examples of unplanned events may include:

1) Unexpected operational events which cause the equipment to perform the function specified by this Surveillance, for which adequate documentation of the required performance is available; and

2) Post corrective maintenance testing that requires performance of this Surveillance in order to restore the component to OPERABLE, provided the maintenance was required, or performed in conjunction with maintenance required to maintain OPERABILITY or reliability.

SR 3.8.4.126 This SR requires that each diesel generator battery charger be capable of recharging its associated battery from a capacity or service discharge test while supplying normal loads, or alternatively, operating at current limit for a minimum of 4 1/2 hours at a nominal 125 VDC. This requirement is based on verifies the design capacity of the DG battery chargers (Ref. 13) and their performance characteristic of current limit operation for a substantial portion of the recharge period. Battery charger output current is limited to a maximum of 140% of the 20 amp rated output. Recharging the battery verifies the output capability of the charger can be sustained, that current limit adjustments are properly set and that protective devices will not inhibit performance at current limit settings. According to Regulatory Guide 1.32 (Ref. 65), the battery charger supply is required recommended to be based on the largest combined demands of the various steady state loads and the charging capacity to restore the battery from the design minimum charge state to the fully charged state, irrespective of the status of the plant during these demand occurrences. Verifying the capability of the charger to operate in a sustained current limit condition The minimum required amperes and duration ensures that these requirements can be satisfied.

(continued)

Watts Bar-Unit 1 B 3.8-63 Revision 112

DC Sources-Operating B 3.8.4 BASES SURVEILLANCE SR 3.8.4.126 (continued)

REQUIREMENTS This SR provides two options. One option requires that each battery charger be capable of supplying 20 amps at the minimum established float voltage (127.6 V DC) for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months . The ampere requirements are based on the output rating of the chargers. The voltage requirements are based on the charger voltage level after a response to a loss of AC power.

The other option requires that each vital battery charger be capable of recharging the battery after a service test coincident with supplying the largest coincident demands of the various continuous steady state loads (irrespective of the status of the plant during which these demands occur). This level of loading may not normally be available following the battery service test and will need to be supplemented with additional loads. The duration for this test may be longer than the charger sizing criteria since the battery recharge is affected by float voltage, temperature, and the exponential decay in charging current. The battery is recharged when the measured charging current is 1 amp.

The Surveillance Frequency is acceptable, given the plant conditions required to perform the test and the other administrative controls existing to ensure adequate charger performance during these 18 month intervals. In addition, this Frequency is intended to be consistent with expected fuel cycle lengths.

For the DG DC electrical subsystem, this Surveillance may be performed in MODES 1, 2, 3, or 4 in conjunction with LCO 3.8.1.B since the DG DC electrical power subsystem supplies loads only for the inoperable diesel generator and would not otherwise challenge safety systems supplied from vital electrical distribution systems. If available, the C-S DG and its associated DC electrical power subsystem may be substituted in accordance with LCO Note 2.

Additionally, credit may be taken for unplanned events that satisfy this SR.

Examples of unplanned events may include:

1) Unexpected operational events which cause the equipment to perform the function specified by this Surveillance, for which adequate documentation of the required performance is available; and

2) Post corrective maintenance testing that requires performance of this Surveillance in order to restore the component to OPERABLE, provided the maintenance was required, or performed in conjunction with maintenance required to maintain OPERABILITY or reliability.

SR 3.8.4.137 A battery service test is a special test of battery capability, as found, to satisfy the design requirements (battery duty cycle) of the DC electrical power system. The discharge rate and test length should correspond to worst case design duty cycle requirements based on References 108 and 1210.

(continued)

Watts Bar-Unit 1 B 3.8-64 Revision 19, 66 Amendment 12

DC Sources-Operating B 3.8.4 BASES SURVEILLANCE SR 3.8.4.137 (continued)

REQUIREMENTS The Surveillance Frequency of 18 months is consistent with the recommendations of Regulatory Guide 1.32 (Ref. 65) and Regulatory Guide 1.129 (Ref. 119), which state that the battery service test should be performed during refueling operations or at some other outage, with intervals between tests, not to exceed 18 months.

This SR is modified by two Notes. Note 1 allows the performance of a modified performance discharge test in lieu of a service test once per 60 months. The modified performance discharge test is a simulated duty cycle consisting of just two rates; the one minute rate published for the battery or the largest current load of the duty cycle, followed by the test rate employed for the performance test, both of which envelope the duty cycle of the service test. Since the ampere-hours removed by a rated one minute discharge represents a very small portion of the battery capacity, the test rate can be changed to that for the performance test without compromising the results of the performance discharge test. The battery terminal voltage for the modified performance discharge test should remain above the minimum battery terminal voltage specified in the battery service test for the duration of time equal to that of the service test.

A modified discharge test is a test of the battery capacity and its ability to provide a high rate, short duration load (usually the highest rate of the duty cycle.) This will often confirm the battery's ability to meet the critical period of the load duty cycle, in addition to determining its percentage of rated capacity. Initial conditions for the modified performance discharge test should be identical to those specified for a service test.

The reason for Note 2 is that performing the Surveillance may perturb the vital electrical distribution system and challenge safety systems. However, this Surveillance may be performed in MODES l, 2, 3, or 4 provided that Vital Battery V is substituted in accordance with LCO Note l. For the DG DC electrical subsystem, this surveillance may be performed in MODES l, 2, 3, or 4 in conjunction with LCO 3.8.l.B since the supplied loads are only for the inoperable diesel generator and would not otherwise challenge safety system loads which are supplied from vital electrical distribution systems. If available, the C-S DG and its associated DC electrical power subsystem may be substituted in accordance with LCO Note 2. Additionally, credit may be taken for unplanned events that satisfy this SR. Examples of unplanned events may include:

1) Unexpected operational events which cause the equipment to perform the function specified by this Surveillance, for which adequate documentation of the required performance is available; and (continued)

Watts Bar-Unit 1 B 3.8-65 Revision 19 Amendment 12

DC Sources-Operating B 3.8.4 BASES SURVEILLANCE SR 3.8.4.137 (continued)

REQUIREMENTS

2) Post corrective maintenance testing that requires performance of this Surveillance in order to restore the component to OPERABLE, provided the maintenance was required, or performed in conjunction with maintenance required to maintain OPERABILITY or reliability.

SR 3.8.4.14 A battery performance discharge test is a test of constant current capacity of a battery, normally done in the as found condition, after having been in service, to detect any change in the capacity determined by the acceptance test. The test is intended to determine overall battery degradation due to age and usage.

A battery modified performance discharge test is described in the Bases for 3.8.4.13. Either the battery performance discharge test or the modified performance discharge test is acceptable for satisfying SR 3.8.4.14; however, only the modified performance discharge test may be used to satisfy SR 3.8.4.14 while satisfying the requirements of SR 3.8.4.13 at the same time.

The acceptance criteria for this Surveillance are consistent with IEEE-450 (Ref. 9) and IEEE-485 (Ref. 5). These references recommend that the battery be replaced if its capacity is below 80% of the manufacturer rating. A capacity of 80% shows that the battery rate of deterioration is increasing, even if there is ample capacity to meet the load requirements.

The Surveillance Frequency for this test is normally 60 months. If the battery shows degradation, or if the battery has reached 85% of its expected life and capacity is < 100% of the manufacturer's rating, the Surveillance Frequency is 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 that retain capacity > 100% of the manufacturer's rating.

Degradation is indicated, according to IEEE-450 (Ref. 9), when the battery capacity drops by more than 10% relative to its capacity on the previous performance test or when it is > 10% below the manufacturer rating. These Frequencies are consistent with the recommendations in IEEE-450 (Ref. 9).

(continued)

Watts Bar-Unit 1 B 3.8-66 Revision 19 Amendment 12

DC Sources-Operating B 3.8.4 BASES SURVEILLANCE SR 3.8.4.14 (continued)

REQUIREMENTS This SR is modified by a Note. The reason for the Note is that performing the Surveillance may perturb the vital electrical distribution system and challenge safety systems. However, this Surveillance may be performed in MODES l, 2, 3, or 4 provided that Vital Battery V is substituted in accordance with LCO Note l.

For the DG DC electrical subsystem, this surveillance may be performed in MODES l, 2, 3, or 4 in conjunction with LCO 3.8.l.B since the supplied loads are only for the inoperable diesel generator and would not otherwise challenge safety system loads which are supplied from vital electrical distribution systems. If available, the C-S DG and its associated DC electrical power subsystem may be substituted in accordance with LCO Note 2. Additionally, credit may be taken for unplanned events that satisfy this SR. Examples of unplanned events may include:

1) Unexpected operational events which cause the equipment to perform the function specified by this Surveillance, for which adequate documentation of the required performance is available; and

2) Post corrective maintenance testing that requires performance of this Surveillance in order to restore the component to OPERABLE, provided the maintenance was required, or performed in conjunction with maintenance required to maintain OPERABILITY or reliability.

(continued)

Watts Bar-Unit 1 B 3.8-67 Revision 19 Amendment 12

DC Sources-Operating B 3.8.4 BASES (continued)

REFERENCES 1. Title 10, Code of Federal Regulations, Part 50, Appendix A, General Design Criterion 17, Electric Power System.

2. Regulatory Guide 1.6, Independence Between Redundant Standby (Onsite) Power Sources and Between Their Distribution Systems, U.S.

Nuclear Regulatory Commission, March 10, 1971.

3. IEEE-308-1971, IEEE Standard Criteria for Class 1E Power Systems for Nuclear Power Generating Stations, Institute of Electrical and Electronic Engineers.

4. Watts Bar FSAR, Section 8.3.2, DC Power System.

5. IEEE-485-1983, Recommended Practices for Sizing Large Lead Storage Batteries for Generating Stations and Substations, Institute of Electrical and Electronic Engineers.

65. Regulatory Guide 1.32, Criteria for Safety-Related Electric Power Systems for Nuclear Power Plants, February 1977, U.S. Nuclear Regulatory Commission.

76. Watts Bar FSAR, Section 15, Accident Analysis and Section 6 Engineered Safety Features.

87. Regulatory Guide 1.93, Availability of Electric Power Sources, U.S.

Nuclear Regulatory Commission, December 1974.

9. IEEE-450-1980/1995, IEEE Recommended Practice for Maintenance Testing and Replacement of Large Lead Storage Batteries for Generating Stations and Subsystems, Institute of Electrical and Electronic Engineers.

108. TVA Calculation WBN EEB-MS-TI11-0003, 125 VDC Vital Battery and Charger Evaluation.

119. Regulatory Guide 1.129, Maintenance Testing and Replacement of Large Lead Storage Batteries for Generating Stations and Subsystems, U.S. Nuclear Regulatory Commission, February 1978.

(continued)

Watts Bar-Unit 1 B 3.8-68

DC Sources-Operating B 3.8.4 BASES REFERENCES 1210. TVA Calculation WBN EEB-MS-TI11-0062, "125 V DC Diesel Generator (continued) Control Power System Evaluation."

13. Watts Bar FSAR, Section 8.3.1, "AC Power System."

Watts Bar-Unit 1 B 3.8-69

DC Sources - Shutdown B 3.8.5 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.5 DC Sources - Shutdown BASES BACKGROUND A description of the DC sources is provided in the Bases for LCO 3.8.4, "DC Sources - Operating."

APPLICABLE The initial conditions of Design Basis Accident and transient analyses in SAFETY ANALYSES the FSAR, Section 6 (Ref. 1) and Section 15 (Ref. 1), assume that Engineered Safety Feature systems are OPERABLE. The vital DC electrical power system provides normal and emergency DC electrical power for the emergency auxiliaries, and control and switching during all MODES of operation.

The DG battery systems provide DC power for the DGs.

The OPERABILITY of the DC sources is consistent with the initial assumptions of the accident analyses and the requirements for the supported systems OPERABILITY.

The OPERABILITY of the minimum DC electrical power sources during MODES 5 and 6, and during movement of irradiated fuel assemblies ensures that:

a. The plant can be maintained in the shutdown or refueling condition for extended periods;

b. Sufficient instrumentation and control capability is available for monitoring and maintaining the plant status; and

c. Adequate DC electrical power is provided to mitigate events postulated during shutdown, such as a fuel handling accident.

The DC sources satisfy Criterion 3 of the NRC Policy Statement.

(continued)

Watts Bar-Unit 1 B 3.8-70

DC Sources - Shutdown B 3.8.5 BASES (continued)

LCO The 125V Vital DC electrical power subsystems, each vital subsystem channel consisting of a battery bank, associated battery charger, and the corresponding control equipment and interconnecting cabling within the channel; and the DG DC electrical power subsystems, each consisting of a battery, a battery charger, and the corresponding control equipment and interconnecting cabling, are required to be OPERABLE to support required trains subsystems of the distribution systems required OPERABLE by LCO 3.8.10, "Distribution Systems -

Shutdown" and the required DGs required OPERABLE by LCO 3.8.2, "AC Sources-Shutdown." As a minimum, one vital DC electrical power train subsystem (i.e., Channels I and III, or II and IV) and two DG DC electrical power subsystems (i.e., 1A-A and 2A-A or 1B-B and 2B-B) shall be OPERABLE. This ensures the availability of sufficient DC electrical power sources to operate the plant in a safe manner and to mitigate the consequences of postulated events during shutdown (e.g., fuel handling accidents).

The LCO is modified by two a Notes. The Note 1 indicates that Vital Battery V may be substituted for any of the required vital batteries. However, the fifth battery cannot be declared OPERABLE until it is connected electrically in place of another battery and it has satisfied applicable Surveillance Requirements.

Note 2 has been added to indicate that the C-S DG and its associated DC subsystem may be substituted for any of the required DGs. However, the C-S DG and its associated DC subsystem cannot be declared OPERABLE until it is connected electrically in place of another DG, and it has satisfied applicable Surveillance Requirements.

APPLICABILITY The DC electrical power sources required to be OPERABLE in MODES 5 and 6, and during movement of irradiated fuel assemblies, provide assurance that:

a. Required features needed to mitigate a fuel handling accident are available; (continued)

Watts Bar-Unit 1 B 3.8-71

DC Sources - Shutdown B 3.8.5 BASES APPLICABILITY b. Required features necessary to mitigate the effects of events that can (continued) lead to core damage during shutdown are available; and

c. Instrumentation and control capability is available for monitoring and maintaining the plant in a cold shutdown condition or refueling condition.

The DC electrical power requirements for MODES 1, 2, 3, and 4 are covered in LCO 3.8.4.

ACTIONS A.1, A.2, and A.3 Condition A represents one subsystem with one or two battery charger(s) inoperable (e.g., the voltage limit of SR 3.8.4.1 is not maintained). The ACTIONS provide a tiered response that focuses on returning the battery to the fully charged state and restoring a fully qualified charger to OPERABLE status in a reasonable time period. Required Action A.1 requires that the battery terminal voltage be restored to greater than or equal to the minimum established float voltage within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months . This time provides for returning the inoperable charger to OPERABLE status or providing an alternate means of restoring battery terminal voltage to greater than or equal to the minimum established float voltage.

Restoring the battery terminal voltage to greater than or equal to the minimum established float voltage provides good assurance that, within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , the battery will be restored to its fully charged condition (Required Action A.2) from any discharge that might have occurred due to the charger inoperability.

A discharged battery having terminal voltage of at least the minimum established float voltage indicates that the battery is on the exponential charging current portion (the second part) of its recharge cycle. The time to return a battery to its fully charged state under this condition is simply a function of the amount of the previous discharge and the recharge characteristic of the battery. Thus there is good assurance of fully recharging the battery within [12] hours, avoiding a premature shutdown with its own attendant risk.

If established battery terminal float voltage cannot be restored to greater than or equal to the minimum established float voltage within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months , and the charger is not operating in the current-limiting mode, a faulty charger is indicated. A faulty charger that is incapable of maintaining established battery terminal float voltage does not provide assurance that it can revert to and operate properly in the current limit mode that is necessary during the recovery period following a battery discharge event that the DC system is designed for.

If the charger is operating in the current limit mode after 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months that is an indication that the battery is partially discharged and its capacity margins will be reduced. The time to return the battery to its fully charged condition in this case (continued)

Watts Bar-Unit 1 B 3.8-72

DC Sources - Shutdown B 3.8.5 BASES ACTIONS A.1, A.2, and A.3 (continued) is a function of the battery charger capacity, the amount of loads on the associated DC system, the amount of the previous discharge, and the recharge characteristic of the battery. The charge time can be extensive, and there is not adequate assurance that it can be recharged within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months (Required Action A.2).

Required Action A.2 requires that the battery float current be verified as less than or equal to 2 amps. This indicates that, if the battery had been discharged as the result of the inoperable battery charger, it has now been fully recharged. If at the expiration of the initial 12 hour1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months period the battery float current is not less than or equal to 2 amps this indicates there may be additional battery problems and the battery must be declared inoperable.

Required Action A.3 limits the restoration time for the inoperable battery charger to 7 days. This action is applicable if an alternate means of restoring battery terminal voltage to greater than or equal to the minimum established float voltage has been used (e.g., balance of plant non-Class 1E battery charger). The 7 day Completion Time reflects a reasonable time to effect restoration of the qualified battery charger to OPERABLE status.

AB.1, AB.2.1, AB.2.2, AB.2.3, and AB.2.4 If two trains subsystems are required by LCO 3.8.10, the remaining train subsystem with DC power available may be capable of supporting sufficient systems to allow continuation of CORE ALTERATIONS and fuel movement. By allowing the option to declare required features inoperable with the associated vital DC power source(s) inoperable, appropriate restrictions will be implemented in accordance with the affected required features LCO ACTIONS. In many instances, this option may involve undesired administrative efforts. Therefore, the allowance for sufficiently conservative actions is made (i.e., to suspend CORE ALTERATIONS, movement of irradiated fuel assemblies, and operations involving positive reactivity additions). The Required Action to suspend positive reactivity additions does not preclude actions to maintain or increase reactor vessel inventory, provided the required SDM is maintained.

Suspension of these activities shall not preclude completion of actions to establish a safe conservative condition. These actions minimize probability of the occurrence of postulated events. It is further required to immediately initiate action to restore the required vital DC electrical power subsystems and to continue this action until restoration is accomplished in order to provide the necessary DC electrical power to the plant safety systems.

(continued)

Watts Bar-Unit 1 B 3.8-73

DC Sources - Shutdown B 3.8.5 BASES ACTIONS AB.1, AB.2.1, AB.2.2, AB.2.3, and AB.2.4 (continued)

The Completion Time of immediately is consistent with the required times for actions requiring prompt attention. The restoration of the required vital DC electrical power subsystems should be completed as quickly as possible in order to minimize the time during which the plant safety systems may be without sufficient power.

BC.1 If the DG DC electrical power subsystem cannot be restored to OPERABLE status in the associated Completion Time, the associated DG may be incapable of performing its intended function and must be immediately declared inoperable.

This declaration also requires entry into applicable Conditions and Required Actions for an inoperable DG, LCO 3.8.2, "AC Sources-Shutdown."

SURVEILLANCE SR 3.8.5.1 REQUIREMENTS SR 3.8.5.1 requires performance of all Surveillances required by SR 3.8.4.1 through SR 3.8.4.147. Therefore, see the corresponding Bases for LCO 3.8.4 for a discussion of each SR.

This SR is modified by a Note. The reason for the Note is to preclude requiring the OPERABLE DC sources from being discharged below their capability to provide the required power supply or otherwise rendered inoperable during the performance of SRs. It is the intent that these SRs must still be capable of being met, but actual performance is not required.

REFERENCES 1. Watts Bar FSAR, Section 15, "Accident Analysis" and Section 6, "Engineered Safety Features."

2. Watts Bar FSAR, Section 8.0, "Electric Power."

Watts Bar-Unit 1 B 3.8-74

Battery Cell Parameters B 3.8.6 B 3.8 ELECTRICAL POWER SYSTEMS B 3.8.6 Battery Cell Parameters BASES BACKGROUND This LCO delineates the limits on battery float current as well as electrolyte temperature, level, and float voltage, and specific gravity for the 125V vital DC electrical power subsystem and diesel generator (DG) batteries. A discussion of these batteries and their OPERABILITY requirements is provided in the Bases for LCO 3.8.4, "DC Sources - Operating," and LCO 3.8.5, "DC Sources -

Shutdown." In addition to the limitations of this Specification, the Battery Monitoring and Maintenance Program also implements a program specified in Specification 5.7.2.22 for monitoring various battery parameters.

The battery cells are of flooded lead acid construction with a nominal specific gravity of 1.215. This specific gravity corresponds to an open circuit battery voltage of approximately 120 V for 60 cell battery (i.e., cell voltage of 2.063 volts per cell (Vpc)). The open circuit voltage is the voltage maintained when there is no charging or discharging. Optimal long term performance however, is obtained by maintaining a float voltage 2.20 to 2.25 Vpc. This provides adequate over-potential which limits the formation of lead sulfate and self discharge. The nominal float voltage of 2.22 Vpc corresponds to a total float voltage output of 133.2 V for a 60 cell battery as discussed in the FSAR, Chapter 8 (Ref. 3).

APPLICABLE The initial conditions of Design Basis Accident (DBA) and transient analyses SAFETY in the FSAR, Section 6 (Ref. 1) and Section 15 (Ref. 1), assume Engineered ANALYSES Safety Feature systems are OPERABLE. The vital DC electrical power system provides normal and emergency DC electrical power for the emergency auxiliaries, and control and switching during all MODES of operation. The DG battery systems provide DC power for the DGs.

The OPERABILITY of the DC subsystems is consistent with the initial assumptions of the accident analyses and is based upon meeting the design basis of the plant. This includes maintaining at least one train subsystem of DC sources OPERABLE during accident conditions, in the event of:

a. An assumed loss of all offsite AC power or all onsite AC power; and

b. A worst case single failure.

Battery cell parameters satisfy the Criterion 3 of the NRC Policy Statement.

(continued)

Watts Bar-Unit 1 B 3.8-74

Battery Cell Parameters B 3.8.6 BASES (continued)

LCO Battery cell parameters must remain within acceptable limits to ensure availability of the required DC power to shut down the reactor and maintain it in a safe condition after an anticipated operational occurrence or a postulated DBA.

Electrolyte Battery parameter limits are conservatively established, allowing continued DC electrical system function even with Category A and B limits not met. Additional preventative maintenance, testing, and monitoring performed in accordance with the Battery Monitoring and Maintenance Program is conducted as specified in Specification 5.7.2.22.

APPLICABILITY The battery cell parameters are required solely for the support of the associated vital DC and DG DC electrical power subsystems. Therefore, battery electrolyte is parameter limits are only required when the DC power source is required to be OPERABLE. Refer to the Applicability discussion in Bases for LCO 3.8.4 and LCO 3.8.5.

ACTIONS A.1, A.2, and A.3 With one or more cells in one or more batteries not within limits (i.e., Category A limits not met, Category B limits not met, or Category A and B limits not met) but within the Category C limits specified in Table 3.8.6-1 in the accompanying LCO, the battery is degraded but there is still sufficient capacity to perform the intended function. Therefore, the affected battery is not required to be considered inoperable solely as a result of Category A or B limits not met, and operation is permitted for a limited period.

The pilot cell electrolyte level and float voltage are required to be verified to meet the Category C limits within 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months (Required Action A.1). This check will provide a quick indication of the status of the remainder of the battery cells. One hour provides time to inspect the electrolyte level and to confirm the float voltage of the pilot cells. One hour is considered a reasonable amount of time to perform the required verification.

Verification that the Category C limits are met (Required Action A.2) provides assurance that during the time needed to restore the parameters to the Category A and B limits, the battery is still capable of performing its intended function. A period of 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months is allowed to complete the initial verification because specific gravity measurements must be obtained for each connected cell. Taking into consideration both the time required to perform the required verification and the assurance that the battery cell (continued)

Watts Bar-Unit 1 B 3.8-75

Battery Cell Parameters B 3.8.6 BASES ACTIONS A.1, A.2, and A.3 (continued) parameters are not severely degraded, this time is considered reasonable. The verification is repeated at 7 day intervals until the parameters are restored to Category A and B limits. This periodic verification is consistent with the normal Frequency of pilot cell surveillances.

Continued operation is only permitted for 31 days before battery cell parameters must be restored to within Category A and B limits. With the consideration that, while battery capacity is degraded, sufficient capacity exists to perform the intended function and to allow time to fully restore the battery cell parameters to normal limits, this time is acceptable prior to declaring the battery inoperable.

A.1, A.2, and A.3 With one or more cells in one or more batteries in one vital DC subsystem

< 2.07 V, the battery cell is degraded. Within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months verification of the required battery charger OPERABILITY is made by monitoring the battery terminal voltage (SR 3.8.4.1) and of the overall battery state of charge by monitoring the battery float charge current (SR 3.8.6.1). This assures that there is still sufficient battery capacity to perform the intended function. Therefore, the affected battery is not required to be considered inoperable solely as a result of one or more cells in one or more batteries < 2.07 V, and continued operation is permitted for a limited period up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

Since the Required Actions only specify "perform," a failure of SR 3.8.4.1 or SR 3.8.6.1 acceptance criteria does not result in this Required Action not met.

However, if one of the SRs is failed the appropriate Condition(s), depending on the cause of the failures, is entered. If SR 3.8.6.1 is failed then there is not assurance that there is still sufficient battery capacity to perform the intended function and the battery must be declared inoperable immediately.

B.1 and B.2 One or more batteries in one vital DC subsystem with float current > 2 amps indicates that a partial discharge of the battery capacity has occurred. This may be due to a temporary loss of a battery charger or possibly due to one or more battery cells in a low voltage condition reflecting some loss of capacity. Within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months verification of the required battery charger OPERABILITY is made by monitoring the battery terminal voltage. If the terminal voltage is found to be less than the minimum established float voltage there are two possibilities, the battery charger is inoperable or is operating in the current limit mode. Condition A addresses charger inoperability. If the charger is operating in the current limit mode after 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months that is an indication that the battery has been substantially discharged and likely cannot perform its required design functions. The time to return the battery to its fully charged condition in this case is a function of the (continued)

Watts Bar-Unit 1 B 3.8-76

Battery Cell Parameters B 3.8.6 BASES ACTIONS B.1 and B.2 (continued) battery charger capacity, the amount of loads on the associated DC system, the amount of the previous discharge, and the recharge characteristic of the battery.

The charge time can be extensive, and there is not adequate assurance that it can be recharged within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months (Required Action B.2). The battery must therefore be declared inoperable.

If the float voltage is found to be satisfactory but there are one or more battery cells with float voltage less than 2.07 V, the associated "OR" statement in Condition H is applicable and the battery must be declared inoperable immediately. If float voltage is satisfactory and there are no cells less than 2.07 V there is good assurance that, within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , the battery will be restored to its fully charged condition (Required Action B.2) from any discharge that might have occurred due to a temporary loss of the battery charger.

A discharged battery with float voltage (the charger setpoint) across its terminals indicates that the battery is on the exponential charging current portion (the second part) of its recharge cycle. The time to return a battery to its fully charged state under this condition is simply a function of the amount of the previous discharge and the recharge characteristic of the battery. Thus there is good assurance of fully recharging the battery within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , avoiding a premature shutdown with its own attendant risk.

If the condition is due to one or more cells in a low voltage condition but still greater than 2.07 V and float voltage is found to be satisfactory, this is not indication of a substantially discharged battery and 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is a reasonable time prior to declaring the battery inoperable.

Since Required Action B.1 only specifies "perform," a failure of SR 3.8.4.1 acceptance criteria does not result in the Required Action not met. However, if SR 3.8.4.1 is failed, the appropriate Condition(s), depending on the cause of the failure, is entered.

C.1, C.2, and C.3 With one or more cells in one or more batteries in one DG DC subsystem

< 2.07 V, the battery cell is degraded. Within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months verification of the required battery charger OPERABILITY is made by monitoring the battery terminal voltage (SR 3.8.4.2) and of the overall battery state of charge by monitoring the battery float charge current (SR 3.8.6.2). This assures that there is still sufficient battery capacity to perform the intended function.

Therefore, the affected battery is not required to be considered inoperable solely as a result of one or more cells in one or more batteries < 2.07 V, and continued operation is permitted for a limited period up to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

(continued)

Watts Bar-Unit 1 B 3.8-77

Battery Cell Parameters B 3.8.6 BASES ACTIONS C.1, C.2, and C.3 (continued)

Since the Required Actions only specify "perform," a failure of SR 3.8.4.2 or SR 3.8.6.2 acceptance criteria does not result in this Required Action not met.

However, if one of the SRs is failed the appropriate Condition(s), depending on the cause of the failures, is entered. If SR 3.8.6.2 is failed then there is not assurance that there is still sufficient battery capacity to perform the intended function and the battery must be declared inoperable immediately.

D.1 and D.2 One or more batteries in one DG DC subsystem with float current > 1 amps indicates that a partial discharge of the battery capacity has occurred. This may be due to a temporary loss of a battery charger or possibly due to one or more battery cells in a low voltage condition reflecting some loss of capacity. Within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months verification of the required battery charger OPERABILITY is made by monitoring the battery terminal voltage. If the terminal voltage is found to be less than the minimum established float voltage there are two possibilities, the battery charger is inoperable or is operating in the current limit mode. Condition B addresses charger inoperability. If the charger is operating in the current limit mode after 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months that is an indication that the battery has been substantially discharged and likely cannot perform its required design functions. The time to return the battery to its fully charged condition in this case is a function of the battery charger capacity, the amount of loads on the associated DC system, the amount of the previous discharge, and the recharge characteristic of the battery.

The charge time can be extensive, and there is not adequate assurance that it can be recharged within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months (Required Action D.2). The battery must therefore be declared inoperable.

If the float voltage is found to be satisfactory but there are one or more battery cells with float voltage less than 2.07 V, the associated "OR" statement in Condition H is applicable and the battery must be declared inoperable immediately. If float voltage is satisfactory and there are no cells less than 2.07 V there is good assurance that, within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , the battery will be restored to its fully charged condition (Required Action D.2) from any discharge that might have occurred due to a temporary loss of the battery charger.

A discharged battery with float voltage (the charger setpoint) across its terminals indicates that the battery is on the exponential charging current portion (the second part) of its recharge cycle. The time to return a battery to its fully charged state under this condition is simply a function of the amount of the previous discharge and the recharge characteristic of the battery. Thus there is good assurance of fully recharging the battery within 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months , avoiding a premature shutdown with its own attendant risk.

If the condition is due to one or more cells in a low voltage condition but still greater than 2.07 V and float voltage is found to be satisfactory, this is not (continued)

Watts Bar-Unit 1 B 3.8-78

Battery Cell Parameters B 3.8.6 BASES ACTIONS D.1 and D.2 (continued) indication of a substantially discharged battery and 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is a reasonable time prior to declaring the battery inoperable.

Since Required Action D.1 only specifies "perform," a failure of SR 3.8.4.2 acceptance criteria does not result in the Required Action not met. However, if SR 3.8.4.2 is failed, the appropriate Condition(s), depending on the cause of the failure, is entered.

E.1, E.2, and E.3 With one or more required batteries in one vital DC subsystem or one DG battery with one or more cells electrolyte level above the top of the plates, but below the minimum established design limits, the battery still retains sufficient capacity to perform the intended function. Therefore, the affected battery is not required to be considered inoperable solely as a result of electrolyte level not met. Within 31 days the minimum established design limits for electrolyte level must be re-established.

With electrolyte level below the top of the plates there is a potential for dryout and plate degradation. Required Actions E.1 and E.2 address this potential (as well as provisions in Specification 5.7.2.22, Battery Monitoring and Maintenance Program). They are modified by a Note that indicates they are only applicable if electrolyte level is below the top of the plates. Within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months level is required to be restored to above the top of the plates. The Required Action E.2 requirement to verify that there is no leakage by visual inspection and the Specification 5.7.2.22.b item to initiate action to equalize and test in accordance with manufacturer's recommendation. They are performed following the restoration of the electrolyte level to above the top of the plates. Based on the results of the manufacturer's recommended testing the battery(ies) may have to be declared inoperable and the affected cell(s) replaced.

F.1 With one or more batteries in one vital DC subsystem or one DG battery with pilot cell temperature less than the minimum established design limits, 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months is allowed to restore the temperature to within limits. A low electrolyte temperature limits the current and power available. Since the battery is sized with margin, while battery capacity is degraded, sufficient capacity exists to perform the intended function and the affected battery is not required to be considered inoperable solely as a result of the pilot cell temperature not met.

(continued)

Watts Bar-Unit 1 B 3.8-79

Battery Cell Parameters B 3.8.6 BASES ACTIONS G.1 (continued)

With one or more batteries in redundant vital DC subsystems with battery parameters not within limits there is not sufficient assurance that battery capacity has not been affected to the degree that the batteries can still perform their required function, given that redundant batteries are involved. With redundant batteries involved this potential could result in a total loss of function on multiple systems that rely upon the batteries. With more than one DG battery with battery parameters not within limits there is not sufficient assurance that battery capacity has not been affected to the degree that the batteries can still perform their required function.

The longer Completion Times specified for battery parameters on non-redundant batteries not within limits are therefore not appropriate, and the parameters must be restored to within limits on at least one subsystem within 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months .

BH.1 With one or more batteries with one or more any battery cell parameters outside the Category C limits for any connected cell, allowances of the Required Actions for Condition A, B, C, D, E, F, or G, sufficient capacity to supply the maximum expected load requirement is not assured and the corresponding vital DC or DG DC electrical power subsystem battery must be declared inoperable.

Additionally, other potentially extreme conditions, such as not completing the Required Actions of Condition A within the required Completion Time or average electrolyte temperature of representative cells falling below 60F for the vital batteries or 50F for DG batteries, are also cause for immediately declaring the associated vital DC or DG DC electrical power subsystem inoperable.

discovering one or more vital DC batteries in one subsystem with one or more battery cells float voltage less than 2.07 V and float current greater than 2 amps, or one DG battery cells float voltage greater than or equal to 2.07 V and float current greater than 1 amp, indicates that the battery capacity may not be sufficient to perform the intended functions. The battery must therefore be declared inoperable immediately.

SURVEILLANCE SR 3.8.6.1 REQUIREMENTS This SR verifies that Category A battery cell parameters are consistent with IEEE-450 (Ref. 2), which recommends regular battery inspections (at least one per month) including voltage, specific gravity, and electrolyte temperature of pilot cells.

(continued)

Watts Bar-Unit 1 B 3.8-80

Battery Cell Parameters B 3.8.6 BASES SURVEILLANCE SR 3.8.6.2 REQUIREMENTS (continued) The quarterly inspection of specific gravity and voltage is consistent with IEEE-450 (Ref. 2). In addition, within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of a battery discharge < 110 V (113.5V for Vital Battery V or 106.5 for DG batteries) or a battery overcharge

> 150 V (155 V for Vital Battery V or 145 V for DG batteries), the battery must be demonstrated to meet Category B limits. Transients, such as motor starting transients, which may momentarily cause battery voltage to drop to 110 V (113.5 V for Vital Battery V or 106.5 V for DG batteries), do not constitute a battery discharge provided the battery terminal voltage and float current return to pre-transient values. This inspection is also consistent with IEEE-450 (Ref. 2),

which recommends special inspections following a severe discharge or overcharge, to ensure that no significant degradation of the battery occurs as a consequence of such discharge or overcharge.

SR 3.8.6.3 This Surveillance verification that the average temperature of representative cells is 60F for the vital batteries and 50F for the DG batteries, is consistent with a recommendation of IEEE-450 (Ref. 2), that states that the temperature of electrolytes in representative cells should be determined on a quarterly basis.

Lower than normal temperatures act to inhibit or reduce battery capacity. This SR ensures that the operating temperatures remain within an acceptable operating range. This limit is based on manufacturer recommendations.

Table 3.8.6-1 This table delineates the limits on electrolyte level, float voltage, and specific gravity for three different categories. The meaning of each category is discussed below.

(continued)

Watts Bar-Unit 1 B 3.8-81

Battery Cell Parameters B 3.8.6 BASES SURVEILLANCE Table 3.8.6-1 (continued)

REQUIREMENTS Category A defines the normal parameter limit for each designated pilot cell in each battery. The cells selected as pilot cells are those whose temperature, voltage, and electrolyte specific gravity approximate the state of charge of the entire battery.

The Category A limits specified for electrolyte level are based on manufacturer recommendations and are consistent with the guidance in IEEE-450 (Ref. 2),

with the extra 1/4 inch allowance above the high water level indication for operating margin to account for temperatures and charge effects. In addition to this allowance, footnote a to Table 3.8.6-1 permits the electrolyte level to be above the specified maximum level during equalizing charge, provided it is not overflowing. These limits ensure that the plates suffer no physical damage, and that adequate electron transfer capability is maintained in the event of transient conditions. IEEE-450 (Ref. 2) recommends that electrolyte level readings should be made only after the battery has been at float charge for at least 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

The Category A limit specified for float voltage is 2.13 V per cell. This value is based on the recommendations of IEEE-450 (Ref. 2), which states that prolonged operation of cells < 2.13 V can reduce the life expectancy of cells.

The Category A limit specified for specific gravity for each pilot cell is 1.200 (0.015 below the manufacturer fully charged nominal specific gravity or a battery charging current that had stabilized at a low value). This value is characteristic of a charged cell with adequate capacity. According to IEEE-450 (Ref. 2), the specific gravity readings are based on a temperature of 77F (25C).

The specific gravity readings are corrected for actual electrolyte temperature and level. For each 3F (1.67C) above 77F (25C), 1 point (0.001) is added to the reading; 1 point is subtracted for each 3F below 77F. The specific gravity of the electrolyte in a cell increases with a loss of water due to electrolysis or evaporation.

(continued)

Watts Bar-Unit 1 B 3.8-82

Battery Cell Parameters B 3.8.6 BASES SURVEILLANCE Table 3.8.6-1 (continued)

REQUIREMENTS Category B defines the normal parameter limits for each connected cell. The term "connected cell" excludes any battery cell that may be jumpered out.

The Category B limits specified for electrolyte level and float voltage are the same as those specified for Category A and have been discussed above. The Category B limit specified for specific gravity for each connected cell is 1.195 (0.020 below the manufacturer fully charged, nominal specific gravity) with the average of all connected cells > 1.205 (0.010 below the manufacturer fully charged, nominal specific gravity). These values are based on manufacturer's recommendations. The minimum specific gravity value required for each cell ensures that the effects of a highly charged or newly installed cell will not mask overall degradation of the battery.

Category C defines the limits for each connected cell. These values, although reduced, provide assurance that sufficient capacity exists to perform the intended function and maintain a margin of safety. When any battery parameter is outside the Category C limits, the assurance of sufficient capacity described above no longer exists, and the battery must be declared inoperable.

The Category C limits specified for electrolyte level (above the top of the plates and not overflowing) ensure that the plates suffer no physical damage and maintain adequate electron transfer capability. The Category C limits for float voltage is based on IEEE-450 (Ref. 2), which states that a cell voltage of 2.07 V or below, under float conditions and not caused by elevated temperature of the cell, indicates internal cell problems and may require cell replacement.

The Category C limits of average specific gravity 1.195 is based on manufacturer recommendations (0.020 below the manufacturer recommended (continued)

Watts Bar-Unit 1 B 3.8-83

Battery Cell Parameters B 3.8.6 BASES SURVEILLANCE Table 3.8.6-1 (continued)

REQUIREMENTS fully charged, nominal specific gravity). In addition to that limit, it is required that the specific gravity for each connected cell must be no less than 0.020 below the average of all connected cells. This limit ensures that the effect of a highly charged or new cell does not mask overall degradation of the battery.

The footnotes to Table 3.8.6-1 are applicable to Category A, B, and C specific gravity. Footnote b to Table 3.8.6-1 requires the above mentioned correction for electrolyte level and temperature, with the exception that level correction is not required when battery charging current is < 2 amps on float charge for vital batteries and < 1.0 amps for DG batteries. This current provides, in general, an indication of overall battery condition.

Because of specific gravity gradients that are produced during the recharging process, delays of several days may occur while waiting for the specific gravity to stabilize. A stabilized charger current is an acceptable alternative to specific gravity measurement for determining the state of charge. This phenomenon is discussed in IEEE-450 (Ref. 2). Footnote c to Table 3.8.6-1 allows the float charge current to be used as an alternate to specific gravity for up to 31 days following a battery recharge. Within 31 days each connected cell's specific gravity must be measured to confirm the state of charge. Following a minor battery recharge (such as equalizing charge that does not follow a deep discharge) specific gravity gradients are not significant, and confirming measurements may be made in less than 31 days.

SR 3.8.6.1 and SR 3.8.6.2 Verifying battery float current while on float charge is used to determine the state of charge of the battery. Float charge is the condition in which the charger is supplying the continuous charge required to overcome the internal losses of a battery and maintain the battery in a charged state. The equipment used to monitor float current must have the necessary accuracy and capability to measure electrical currents in the expected range. The float current requirements are based on the float current indicative of a charged battery. The 7 day Frequency is consistent with IEEE-450 (Ref. 2).

SR 3.8.6.1 is modified by a Note that states the float current requirement is not required to be met when battery terminal voltage is less than the minimum established float voltage of SR 3.8.4.1. When this float voltage is not maintained the Required Actions of LCO 3.8.4 ACTION A are being taken, which provide the necessary and appropriate verifications of the battery condition. Furthermore, the float current limit of 2 amps is established based on the nominal float voltage value and is not directly applicable when this voltage is not maintained.

SR 3.8.6.2 is modified by a Note that states the float current requirement is not required to be met when battery terminal voltage is less than the minimum established float voltage of SR 3.8.4.2. When this float voltage is not maintained (continued)

Watts Bar-Unit 1 B 3.8-84

Battery Cell Parameters B 3.8.6 BASES SURVEILLANCE SR 3.8.6.1 and SR 3.8.6.2 (continued)

REQUIREMENTS the Required Actions of LCO 3.8.4 ACTION D are being taken, which provide the necessary and appropriate verifications of the battery condition. Furthermore, the float current limit of 1 amp is established based on the nominal float voltage value and is not directly applicable when this voltage is not maintained.

SR 3.8.6.3 and SR 3.8.6.6 Optimal long term battery performance is obtained by maintaining a float voltage greater than or equal to the minimum established design limits provided by the battery manufacturer, which corresponds to 132 V at the battery terminals, or 2.20 Vpc. This provides adequate overpotential, which limits the formation of lead sulfate and self discharge, which could eventually render the battery inoperable. Float voltages in this range or less, but greater than 2.07 Vpc, are addressed in Specification 5.7.2.22. SRs 3.8.6.3 and 3.8.6.6 require verification that the cell float voltages are equal to or greater than the short term absolute minimum voltage of 2.07 V. The Frequency for cell voltage verification every 31 days for pilot cell and 92 days for each connected cell is consistent with IEEE-450 (Ref. 2).

SR 3.8.6.4 The limit specified for electrolyte level ensures that the plates suffer no physical damage and maintains adequate electron transfer capability. The minimum design electrolyte level is the minimum level indication mark on the battery cell jar. The Frequency is consistent with IEEE-450 (Ref. 2).

SR 3.8.6.5 This Surveillance verifies that the pilot cell temperature is greater than or equal to the minimum established design limit (i.e., 60°F for the vital batteries and 50°F for the DG batteries). Pilot cell electrolyte temperature is maintained above this temperature to assure the battery can provide the required current and voltage to meet the design requirements. Temperatures lower than assumed in battery sizing calculations act to inhibit or reduce battery capacity. The Frequency is consistent with IEEE-450 (Ref. 2).

SR 3.8.6.7 A battery performance discharge test is a test of constant current capacity of a battery, normally done in the as found condition, after having been in service, to detect any change in the capacity determined by the acceptance test. The test is intended to determine overall battery degradation due to age and usage.

Either the battery performance discharge test or the modified performance discharge test is acceptable for satisfying SR 3.8.6.7; however, only the modified (continued)

Watts Bar-Unit 1 B 3.8-85

Battery Cell Parameters B 3.8.6 BASES SURVEILLANCE SR 3.8.6.7 (continued)

REQUIREMENTS performance discharge test may be used to satisfy the battery service test requirements of SR 3.8.4.7.

A modified discharge test is a test of the battery capacity and its ability to provide a high rate, short duration load (usually the highest rate of the duty cycle). This will often confirm the battery's ability to meet the critical period of the load duty cycle, in addition to determining its percentage of rated capacity. Initial conditions for the modified performance discharge test should be identical to those specified for a service test.

It may consist of just two rates; for instance the one minute rate for the battery or the largest current load of the duty cycle, followed by the test rate employed for the performance test, both of which envelope the duty cycle of the service test.

Since the ampere-hours removed by a one minute discharge represents a very small portion of the battery capacity, the test rate can be changed to that for the performance test without compromising the results of the performance discharge test. The battery terminal voltage for the modified performance discharge test must remain above the minimum battery terminal voltage specified in the battery service test for the duration of time equal to that of the service test.

The acceptance criteria for this Surveillance are consistent with IEEE-450 (Ref. 2) and IEEE-485 (Ref. 4). These references recommend that the battery be replaced if its capacity is below 80% of the manufacturer's rating. A capacity of 80% shows that the battery rate of deterioration is increasing, even if there is ample capacity to meet the load requirements. Furthermore, the battery is sized to meet the assumed duty cycle loads when the battery design capacity reaches this 80% limit.

The Surveillance Frequency for this test is normally 60 months. If the battery shows degradation, or if the battery has reached 85% of its expected life and capacity is < 100% of the manufacturer's rating, the Surveillance Frequency is 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 that retain capacity 100% of the manufacturer's ratings.

Degradation is indicated, according to IEEE-450 (Ref. 2), when the battery capacity drops by more than 10% relative to its capacity on the previous performance test or when it is 10% below the manufacturer's rating. These Frequencies are consistent with the recommendations in IEEE-450 (Ref. 2).

This SR is modified by a Note. The reason for the Note is that performing the Surveillance would perturb the electrical distribution system and challenge safety systems. Credit may be taken for unplanned events that satisfy this SR.

(continued)

Watts Bar-Unit 1 B 3.8-86

Battery Cell Parameters B 3.8.6 BASES REFERENCES 1. Watts Bar FSAR, Section 15, "Accident Analysis," and Section 6, "Engineered Safety Features."

2. IEEE-450-1980/19952002, "IEEE Recommended Practice for Maintenance, Testing, and Replacement of Large Vented Lead-Acid Storage Batteries for Generating Stations and SubstationsStationary Applications."

3. Watts Bar FSAR, Section 8, "Electric Power."

4. IEEE-485-1983, "IEEE Recommended Practice for Sizing Large Lead Storage Batteries for Generating Stations and Substations."

Watts Bar-Unit 1 B 3.8-87

WBN Unit 2 Markups of Technical Specification and Bases CNL-18-118 E2-61

DC Sources - Operating 3.8.4 3.8 ELECTRICAL POWER SYSTEMS 3.8.4 DC Sources - Operating LCO 3.8.4 Four channels of The Train A and Train B vital DC electrical power subsystems and four Diesel Generator (DG) DC electrical power subsystems shall be OPERABLE.

NOTE-------------------------------------------

Vital Battery V may be substituted for any of the required vital batteries.

APPLICABILITY: MODES 1, 2, 3, and 4.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One or two required vital A.1 Restore battery terminal 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months battery charger(s) on voltage to greater than or one subsystem equal to the minimum inoperable. established float voltage.

AND A.2 Verify battery float current Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months 2 amps.

AND A.3 Restore vital battery 7 days charger(s) to OPERABLE status.

AB. One vital DC electrical AB.1 Restore vital DC electrical 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months power subsystem power subsystem to inoperable for reasons OPERABLE status.

other than Condition A.

(continued)

Watts Bar - Unit 2 3.8-21

DC Sources - Operating 3.8.4 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME BC. Required Action and BC.1 Be in MODE 3. 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months Associated Completion Time of Condition A or AND B not met.

BC.2 Be in MODE 5. 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months D. One DG DC battery D.1 Restore DG battery terminal 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months charger inoperable. voltage to greater than or equal to the minimum established float voltage.

AND D.2 Verify battery float current Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months 1 amp.

AND D.3 Restore DG battery charger 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months to OPERABLE status.

CE. One DG DC electrical CE.1 Restore DG DC electrical 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months power subsystem power subsystem to inoperable for reasons OPERABLE status.

other than Condition D.

DF. Required Action and DF.1 Declare associated DG Immediately associated Completion inoperable.

Time of Condition CD or E not met.

Watts Bar - Unit 2 3.8-22

DC Sources - Operating 3.8.4 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.4.1 Verify vital battery terminal voltage is 128 V (132 V 7 days for vital battery V) on float charge greater than or equal to the minimum established float voltage.

SR 3.8.4.2 Verify DG battery terminal voltage is 124 V on float 7 days charge greater than or equal to the minimum established float voltage.

SR 3.8.4.3 Verify for the vital batteries that the alternate feeder 7 days breakers to each required battery charger are open.

SR 3.8.4.4 Verify correct breaker alignment and indicated power 7 days availability for each DG 125 V DC distribution panel and associated battery charger SR 3.8.4.5 Verify no visible corrosion at terminals and 92 days connectors for the vital batteries.

OR Verify connection resistance for the vital batteries is 80 E-6 ohm for inter-cell connections, 50 E-6 ohm for inter-rack connections, 120 E-6 ohm for inter-tier connections, and 50 E-6 ohm for terminal connections.

SR 3.8.4.6 Verify no visible corrosion at terminals and 92 days connectors for the DG batteries.

OR Verify connection resistance for the DG batteries is 80 E-6 ohm for inter-cell connections, 50 E-6 ohm for inter-tier connections, and 50 E-6 ohm for terminal connections.

SR 3.8.4.7 Verify battery cells, cell plates, and racks show no 12 months visual indication of physical damage or abnormal deterioration.

(continued)

Watts Bar - Unit 2 3.8-23

DC Sources - Operating 3.8.4 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.4.8 Remove visible terminal corrosion and verify battery 12 months cell to cell and terminal connections are coated with anti-corrosion material.

SR 3.8.4.9 Verify connection resistance for the vital batteries is 12 months 80 E-6 ohm for inter-cell connections, 50 E-6 ohm for inter-rack connections, 120 E-6 ohm for inter-tier connections, and 50 E-6 ohm for terminal connections.

SR 3.8.4.10 Verify connection resistance for the DG batteries is 12 months 80 E-6 ohm for inter-cell connections, 50 E-6 ohm for inter-tier connections, and 50 E-6 ohm for terminal connections.

SR 3.8.4.115 -------------------------------NOTE------------------------------

This Surveillance is normally not performed in MODE 1, 2, 3, or 4. However, credit may be taken for unplanned events that satisfy this SR.

Verify each vital battery charger is capable of 18 months recharging its associated battery from a service or capacity discharge test while supplying normal loads supplies 200 amps at greater than or equal to the minimum established float voltage for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

OR Verify each vital battery charger can recharge the battery to the fully charged state within 36 hours4.166667e-4 days 0.01 hours 5.952381e-5 weeks 1.3698e-5 months while supplying the largest combined demands of the various continuous steady state loads, after a battery discharge to the bounding design basis event discharge state is capable of operating for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months at current limit 220 - 250 amps.

(continued)

Watts Bar - Unit 2 3.8-24

DC Sources - Operating 3.8.4 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.4.126 -------------------------------NOTE------------------------------

Credit may be taken for unplanned events that satisfy this SR.

Verify each diesel generator DG battery charger is 18 months capable of recharging its associated battery from a service or capacity discharge test while supplying normal loads supplies 20 amps at greater than or equal to the minimum established float voltage for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months .

OR Verify each DG battery charger can recharge the battery to the fully charged state within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months while supplying the largest combined demands of the various continuous steady state loads, after a battery discharge to the bounding design basis event discharge state.

SR 3.8.4.137 -------------------------------NOTES----------------------------

1. The modified performance discharge test in SR 3.8.4.146.7 may be performed in lieu of the service test in SR 3.8.4.137 once per 60 months.

2. This Surveillance is not performed in MODE 1, 2, 3, or 4 for required vital batteries. Credit may be taken for unplanned events that satisfy this SR.

Verify battery capacity is adequate to supply, and 18 months maintain in OPERABLE status, the required emergency loads and any connected nonsafety loads for the design duty cycle when subjected to a battery service test.

(continued)

Watts Bar - Unit 2 3.8-25

DC Sources - Operating 3.8.4 SURVEILLANCE REQUIREMENTS (continued)

SURVEILLANCE FREQUENCY SR 3.8.4.14 -------------------------------NOTE------------------------------

This Surveillance is not performed in MODE 1, 2, 3, or 4 for required vital batteries. Credit may be taken for unplanned events that satisfy this SR.

Verify battery capacity is 80% of the manufacturer's 60 months rating when subjected to a performance discharge test or a modified performance discharge test. AND 12 months when battery shows degradation or has reached 85% of expected life with capacity < 100% of manufacturer's rating AND 24 months when battery has reached 85% of the expected life with capacity 100% of manufacturer's rating Watts Bar - Unit 2 3.8-26

DC Sources - Shutdown 3.8.5 3.8 ELECTRICAL POWER SYSTEMS 3.8.5 DC Sources - Shutdown LCO 3.8.5 Vital DC and Diesel Generator (DG) DC electrical power subsystems shall be OPERABLE to support the DC electrical power distribution subsystem(s) required by LCO 3.8.10, "Distribution Systems - Shutdown" and to support the Diesel Generators (DGs) required by LCO 3.8.2, "AC Sources - Shutdown."

NOTES------------------------------------------

Vital Battery V may be substituted for any of the required vital batteries.

APPLICABILITY: MODES 5 and 6, During movement of irradiated fuel assemblies.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One or two required A.1 Restore battery terminal 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months vital battery charger(s) voltage to greater than or on one subsystem equal to the minimum inoperable. established float voltage.

AND AND The redundant A.2 Verify battery float current Once per 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months subsystem vital battery 2 amps.

and charger(s)

OPERABLE. AND A.3 Restore battery charger(s) to 7 days OPERABLE status.

(continued)

Watts Bar - Unit 2 3.8-26

DC Sources - Shutdown 3.8.5 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME AB. One or more required AB.1.1 Declare affected required Immediately vital DC electrical power feature(s) inoperable.

subsystems inoperable for reasons other than OR Condition A.

AB.2.1 Suspend CORE Immediately OR ALTERATIONS.

Required Actions and AND associated Completion Time of Condition A not AB.2.2 Suspend movement of Immediately met. irradiated fuel assemblies.

AND AB.2.3 Initiate action to suspend Immediately operations involving positive reactivity additions.

AND AB.2.4 Initiate action to restore Immediately required DC electrical power subsystems to OPERABLE status.

BC. One required DG DC BC.1 Declare associated DG Immediately electrical power inoperable.

subsystem inoperable.

Watts Bar - Unit 2 3.8-27

DC Sources - Shutdown 3.8.5 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.5.1 -----------------------------NOTE-----------------------------

The following SRs are not required to be performed: SR 3.8.4.115, SR 3.8.4.126, and SR 3.8.4.137, and SR 3.8.4.14.

For DC sources required to be OPERABLE, the In accordance with following SRs are applicable: applicable SRs SR 3.8.4.1 SR 3.8.4.6 SR 3.8.4.11 SR 3.8.4.2 SR 3.8.4.7 SR 3.8.4.12 SR 3.8.4.3 SR 3.8.4.8 SR 3.8.4.13 SR 3.8.4.4 SR 3.8.4.9 SR 3.8.4.14 SR 3.8.4.5 SR 3.8.4.10 Watts Bar - Unit 2 3.8-28

Battery Cell Parameters 3.8.6 3.8 ELECTRICAL POWER SYSTEMS 3.8.6 Battery Cell Parameters LCO 3.8.6 Battery cell parameters for Train A and Train B electrical power subsystem 125 V vital batteries and 125 V diesel generator (DG) batteries shall be within the limits of Table 3.8.6-1.

APPLICABILITY: When associated DC electrical power subsystems and DGs are required to be OPERABLE.

ACTIONS

NOTE-------------------------------------------------------------

Separate Condition entry is allowed for each battery bank.

ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One or more batteries with A.1 Verify pilot cells 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months one or more battery cell electrolyte level and float parameters not within voltage meet Table 3.8.6-Category A or B limits. 1 Category C limits.

AND A.2 Verify battery cell 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months parameters meet Table 3.8.6-1 Category C limits. AND Once per 7 days thereafter AND A.3 Restore battery cell 31 days parameters to category A and B limits of Table 3.8.6-1.

(continued)

Watts Bar - Unit 2 3.8-29

Battery Cell Parameters 3.8.6 ACTIONS CONDITION REQUIRED ACTION COMPLETION TIME A. One or two required vital A.1 Perform SR 3.8.4.1. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months battery(ies) on one subsystem with one or AND more battery cells float voltage < 2.07 V. A.2 Perform SR 3.8.6.1. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months AND A.3 Restore affected cell 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months voltage 2.07 V.

B. One or two required vital B.1 Perform SR 3.8.4.1. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months battery(ies) on one subsystem with float AND current > 2 amps.

B.2 Restore vital battery float 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months current to 2 amps.

C. One DG battery with one C.1 Perform SR 3.8.4.2. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months or more battery cells float voltage < 2.07 V. AND C.2 Perform SR 3.8.6.2. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months AND C.3 Restore affected cell 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months voltage 2.07 V.

D. One DG battery with D.1 Perform SR 3.8.4.2. 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months float current > 1 amp.

AND D.2 Restore vital battery float 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months current to 1 amp.

(continued)

Watts Bar - Unit 2 3.8-30

Battery Cell Parameters 3.8.6 ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME

NOTE------------------- ------------------NOTE-------------------

Required Action E.2 shall be Required Actions E.1 and E.2 are completed if electrolyte level was only applicable if electrolyte level below the top of plates. was below the top of plates.

E. One or two required vital E.1 Restore electrolyte level 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months battery(ies) on one to above top of plates.

subsystem with one or more cells electrolyte AND level less than minimum established design E.2 Verify no evidence of 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months limits. leakage.

OR AND One DG battery with one E.3 Restore electrolyte level 31 days or more cells electrolyte to greater than or equal to level less than minimum minimum established established design design limits.

limits.

F. One or two required vital F.1 Restore battery pilot cell 12 hours1.388889e-4 days 0.00333 hours 1.984127e-5 weeks 4.566e-6 months battery(ies) on one temperature to greater subsystem with pilot cell than or equal to minimum electrolyte temperature established design limits.

less than minimum established design limits.

OR One DG battery with pilot cell electrolyte temperature less than minimum established design limits.

(continued)

Watts Bar - Unit 2 3.8-31

Battery Cell Parameters 3.8.6 (ACTIONS (continued)

CONDITION REQUIRED ACTION COMPLETION TIME G. One or more batteries in G.1 Restore battery parameters to 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months redundant subsystems within limits.

with battery parameters not within limits.

OR More than one DG battery with battery parameters not within limits.

BH. Required Action and BH.1 Declare associated battery Immediately associated Completion inoperable.

Time of Condition A, B, C, D, E, F, or G not met.

OR One or two required vital battery(ies) on one subsystem with one or more battery cells float voltage < 2.07 V and float current > 2 amps.

OR One DG battery with one or more battery cells float voltage < 2.07 V and float current > 1 amp.

One or more batteries with average electrolyte temperature of the representative cells

< 60F for vital batteries and < 50F for DG batteries.

OR One or more batteries with one or more battery cell parameters not within Category C values.

Watts Bar - Unit 2 3.8-32

Battery Cell Parameters 3.8.6 SURVEILLANCE REQUIREMENTS SURVEILLANCE FREQUENCY SR 3.8.6.1 Verify battery cell parameters meet Table 3.8.6-1 7 days Category A limits.

SR 3.8.6.2 Verify battery cell parameters meet Table 3.8.6-1 92 days Category B limits.

AND Once within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after a battery discharge < 110 V for vital batteries (113.5 V for vital battery V) or 106.5 V for DG batteries AND Once within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months after a battery overcharge > 150 V for vital batteries (155 V for vital battery V) or 145 V for DG batteries SR 3.8.6.3 Verify average electrolyte temperature of 92 days representative cells is 60oF for vital batteries and 50oF for the DG batteries.

Insert Surveillance Requirements from next page.

Watts Bar-Unit 2 3.8-33

Insert the following Surveillance Requirements for LCO 3.8.6:

SURVEILLANCE FREQUENCY SR 3.8.6.1 -----------------------------NOTE--------------------------------

Not required to be met when vital battery terminal voltage is less than the minimum established float voltage of SR 3.8.4.1.

Verify each vital battery float current is 2 amps. 7 days SR 3.8.6.2 -----------------------------NOTE--------------------------------