ML13067A030

Overall Integrated Plan in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)

ML13067A030
Person / Time
Site:	Watts Bar
Issue date:	02/28/2013
From:	James Shea Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-12-049
Download: ML13067A030 (92)

Text

Enclosure 1 Attachment 3 is to be withheld from public disclosure under 10 CFR 2.390.

When separated from this submittal, this letter is decontrolled.

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 EA-12-049 February 28, 2013 10 CFR 2.202 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Watts Bar Nuclear Plant, Unit 1 Facility Operating License No. NPF-90 NRC Docket No. 50-390 Watts Bar Nuclear Plant, Unit 2 Construction Permit No. CPPR-92 NRC Docket No. 50-391

Subject:

Tennessee Valley Authority (TVA) - Overall Integrated Plan in Response to the March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049) for Watts Bar Nuclear Plant

References:

1. NRC Order Number EA-1 2-049, "Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," dated March 12, 2012 (ML12054A735)

2. NRC Interim Staff Guidance JLD-ISG-2012-01, "Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," Revision 0, dated August 29, 2012 (ML12229A174)

3. NEI 12-06, "Diverse and Flexible Coping Strategies (FLEX)

Implementation Guide," Revision 0, dated August 2012 (ML12242A378)

4. Letter from TVA to NRC, "Tennessee Valley Authority - Initial Status Report in Response to March 12, 2012, Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Printed on recycled paper

U.S. Nuclear Regulatory Commission Page 2 February 28, 2013 On March 12, 2012, the Nuclear Regulatory Commission (NRC) issued an immediately effective order (Order Number EA-12-049) entitled "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies For Beyond-Design-Basis External Events" to "All Power Reactor Licensees and Holders of Construction Permits in Active or Deferred Status" (Reference 1). The Order indicated that, as a result of the NRC's evaluation of the lessons learned from the March 2011 accident at Fukushima Dai-ichi, the NRC determined that certain actions are required by nuclear power plant licensees and construction permit holders. Specifically, the NRC required additional defense-in-depth measures to address uncertainties associated with protection from beyond-design-basis events. With respect to this Order, the NRC determined that all power reactor licensees and construction permit holders must "develop, implement, and maintain guidance and strategies to maintain or restore core cooling, containment, and SFP [spent fuel pool] cooling capabilities following a beyond-design-basis external event." Specific requirements are outlined in Attachment 2 to the Order.

The Order requires submission of an overall integrated plan, including a description of how compliance with the requirements described in Attachment 2 of the Order will be achieved.

The Order requires the plan to be submitted to the NRC for review by February 28, 2013. In addition, the Order requires submission of an initial status report 60 days following issuance of the final interim staff guidance and at six month intervals following submittal of the overall integrated plan, which delineates progress in implementing the requirements of the Order.

The interim staff guidance containing specific details on implementation of the requirements of the order was scheduled to be issued in August 2012. Finally, the order requires full implementation of its requirements no later than two refueling cycles after submittal of the overall integrated plan, or December 31, 2016, whichever comes first, or prior to issuance of an operating license for units under construction.

The NRC issued Interim Staff Guidance on August 29, 2012 (Reference 2) which endorses industry guidance document NEI 12-06, Revision 0 (Reference 3) with clarifications and exceptions identified in Reference 2. Reference 3, Section 13.1 contains the specific reporting requirements for the overall integrated plan.

By letter dated October 29, 2012 (Reference 4), TVA submitted an initial status report regarding the progress in establishing mitigation strategies for beyond-design-basis external events, as required by the Reference 1 Order.

The purpose of this letter is to provide the overall integrated plan pursuant to Section IV, Condition C.1.a, of Reference 1. This letter confirms TVA has received the Reference 2 interim staff guidance and has an overall integrated plan developed in accordance with the provided guidance for the Watts Bar Nuclear Plant (WBN) to define and deploy strategies that will enhance the ability to cope with conditions resulting from beyond-design-basis external events.

U.S. Nuclear Regulatory Commission Page 3 February 28, 2013 The information in the enclosure to this letter provides the WBN overall integrated plan for mitigation strategies using the guidance contained in Reference 3. The enclosed Integrated Plan is based on conceptual design information. Final design details and associated procedure guidance, status of open items identified in the Enclosure, as well as any revisions to the information contained in the Enclosure, will be provided in the 6-month Integrated Plan updates required by Reference 1.

The information provided in Attachment 3 to the Enclosure is considered to contain information concerning physical protection not otherwise designated as Safeguards Information and is designated "Security Sensitive Information" as defined in 10 CFR 2.390(d)(1). Accordingly, TVA requests that the information provided in Attachment 3 to the Enclosure to this letter be withheld from public disclosure.

The Enclosure describes the plans that TVA will use to meet the regulatory requirements outlined in Attachment 2 of Reference 1, but does not identify any additional actions to be taken by TVA. Therefore, this letter contains no regulatory commitments.

If you have any questions regarding this report, please contact Kevin Casey at (423) 751-8523.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 28th day of February 2013.

Respec ly, J. .hea Vi/e resident, Nuclear Licensing

Enclosure:

Watts Bar Nuclear Plant, Mitigation Strategies for Beyond-Design-Basis External Events Overall Integrated Plan cc (Enclosure):

NRR Director - NRC Headquarters NRO Director - NRC Headquarters NRC Regional Administrator - Region II NRR Project Manager - Watts Bar Nuclear Plant NRC Senior Resident Inspector - Watts Bar Nuclear Plant U.S. Nuclear Regulatory Commission

ENCLOSURE WATTS BAR NUCLEAR PLANT MITIGATION STRATEGIES FOR BEYOND-DESIGN-BASIS EXTERNAL EVENTS OVERALL INTEGRATED PLAN

TENNESSEE VALLEY AUTHORITY WATTS BAR NUCLEAR PLANT UNITS 1 AND 2 FLEX OVERALL INTEGRATED PLAN E-1

General Integrated Plan Elements Watts Bar Units 1 and 2 Determine Applicable Extreme External Hazard Ref: NEI 12-06 Section 4.0 -9.0 JLD-ISG-2012-01 Section 1.0 The Watts Bar site has been evaluated and the following applicable hazards have been identified:

• Seismic events

• External flooding

• Severe storms with high winds

• Snow, ice, and extreme cold

• Extreme heat The Watts Bar site has been reviewed against the Nuclear Energy Institute (NEI) guidance document NEI 12-06 (Reference 2) and determined that the hazards Flexible and Diverse Coping Mitigation Strategies (FLEX) equipment should be protected from include seismic; external flooding; severe storms with high winds; snow, ice and extreme cold; and extreme high temperatures. Watts Bar has determined the functional threats from each of these hazards and identified FLEX equipment that may be affected. The FLEX storage locations will provide the protection required from these hazards.

Watts Bar is also developing procedures and processes to further address plant strategies for responding to these various hazards.

Seismic:

Per NEI 12-06 (Reference 2), seismic hazards must be considered for all nuclear sites. As a result, the credited FLEX equipment will be assessed based on the current Watts Bar seismic licensing basis to ensure that the equipment remains accessible and available after a beyond-design-basis external event (BDBEE) and that the FLEX equipment does not become a target or source of a seismic interaction from other systems, structures or components. From References 4 and 5, Sections 2.5.2.4 and 2.5.2.7, safe shutdown earthquake (SSE) requirements of 0.1 8g horizontal and 0.12 g vertical maximum rock accelerations. For an operating basis earthquake (OBE), the maximum horizontal and vertical ground accelerations are 0.09g and 0.06 g, respectively. The FLEX strategies developed for Watts Bar will include documentation ensuring that any storage locations and deployment routes meet the FLEX seismic criteria.

Liauefaction The liquefaction potential ofrall FLEX deployment routes will be addressed in a future assessment (Open item 01 2).

ExternalFlooding:

The types of events evaluated to determine the worst potential flood included (1) probable maximum storm on the total watershed and critical sub-water sheds including seasonal variations and potential consequent dam failures and (2) dam failures in a postulated SSE or OBE with guide specified concurrent flood conditions.

Those safety-related facilities, systems, and equipment located in the containment structure are protected from flooding by the Shield Building structure with those accesses and penetrations below E-2

the maximum flood level designed and constructed as watertight elements (References 4 and 5, Section 2.4.2.2). From References 4 and 5, Section 2.4.3.6, the Diesel Generator Buildings to the north and the pumping station to the southeast of the main building complex must be protected from flooding to assure plant safety. The Diesel Generator Building's operating floors are at elevation 742.0 ft., which are above the maximum computed elevation, including wind wave run-up. Per References 4 and 5, Section 2.4.14.2.3, the intake pumping station is designed to retain full functional capability to maintain cooling of plant loads. All equipment required to maintain the plant safely during the flood is either designed to operate submerged, is located above the maximum flood level, or is otherwise protected.

Specific analysis of Tennessee River flood levels resulting from ocean front surges and tsunamis is not required because of the inland location of the plant (References 4 and 5, Section 2.4.6). Snow melt and ice jam considerations are also unnecessary because of the temperate zone location of the plant (References 4 and 5, Sections 2.4.2.2 and 2.4.7). Flood waves from landslides into upstream reservoirs required no specific analysis, in part because of the absence of major elevation relief in nearby upstream reservoirs and because the prevailing thin soils offer small slide volume potential compared to the available detention space in reservoirs (References 4 and 5, Section 2.4.2.2). Seiches pose no flood threats because of the size and configuration of the lake and the elevation difference between normal lake level and plant grade (References 4 and 5, Sections 2.4.2.2 and 2.4.5).

Per References 4 and 5, Section 2.4.2.2, the maximum plant site flood level from any cause is Elevation 734.9 ft. This information has been superseded by Reference 9. The maximum plant site flood level from any cause is Elevation 739.2 ft.(still reservoir). This elevation would result from the probable maximum storm. Coincident wind wave activity results in wind waves of up to 2.2 ft. (crest to trough). Run up on the 4:1 slopes approaching the Diesel Generator Building reaches Elevation 741.6 ft. Wind wave run up on the critical wall of the Intake Pumping Station reaches Elevation 741.7 ft. and wind wave run up on the walls of the Auxiliary, Control and Shield Buildings reaches Elevation 741.0 ft (Reference 9).

In summary, all equipment required to maintain the plant safely during all flooding events including the design basis flood (DBF) is either designed to operate submerged, is located above the maximum flood level, or is otherwise protected. Accordingly, FLEX strategies will be developed for consideration of external flooding hazards. In addition, Watts Bar is also developing procedures and strategies for delivery of offsite FLEX equipment during Phase 3 which considers regional impacts from flooding.

High Wind:

Figures 7-1 and 7-2 from Reference 2 were used for this assessment.

Watts Bar is susceptible to hurricanes as the plant site is within the contour lines shown in Figure 7-1 of Reference 2.

It was determined the Watts Bar site has the potential to experience damaging winds caused by a tornado exceeding 130 mph. Figure 7-2 of Reference 2 indicates a maximum wind speed of 200 mph for Region 1 plants, including Watts Bar. Therefore, high-wind hazards are applicable to the Watts Bar site.

In summary, based on available local data and Figures 7-1 and 7-2 of Reference 2, Watts Bar is susceptible to severe storms with high winds so the hazard is screened in.

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Snow, Ice, andExtreme Cold Per the FLEX guidance all sites should consider the temperature ranges and weather conditions for their site in storing and deploying their FLEX equipment. That is, the equipment procured should be suitable for use in the anticipated range of conditions for the site, consistent with normal design practices.

Applicability of snow andextreme cold.-

The Watts Bar Site is located approximately 50 miles northeast of Chattanooga in Rhea County, Tennessee, on the west bank of the Tennessee River at mile 528. The site is approximately 1-1/4 miles south of the Watts Bar Dam and approximately 31 miles north-northeast of the Sequoyah Nuclear Plant (References 4 and 5, Section 2.1.1.1). The approximate site location is given below, from References 4 and 5, Section 2.1.1.1:

LATITUDE (degrees/minutes): 35036' N LONGITUDE (degrees/minutes): 84047' W From References 4 and 5, Section 2.3.2.2, mean temperatures at the Watts Bar site have been in the low 40s'F in the winter at both locations. Extreme minima temperatures recorded were -20'F at Decatur and -10°F at Chattanooga in the winter.

Reference 2 states plants above the 35th parallel should provide the capability to address the hindrances caused by extreme snow and cold. The Watts Bar site is above the 3 5th parallel; therefore, the FLEX strategies must. consider the hindrances caused by extreme snowfall with snow removal equipment, as well as the challenges that extreme cold temperature may present.

Applicability of ice storms.-

The Watts Bar site is not a Level I or 2 region as defined by Figure 8-2 of Reference 2; therefore, the FLEX strategies must consider the hindrances caused by ice storms.

In summary, based on the available local data and Figures 8-1 and 8-2 of Reference 2, the Watts Bar site does experience significant amounts of snow, ice, and extreme cold temperatures; therefore, the hazard is screened in.

Extreme Heat:

Per Reference 2, all sites must address high temperatures. Virtually every state in the lower 48 contiguous United States has experienced temperatures in excess of l10°F. Many states have experienced temperatures in excess of 120°F. Sites that should address high temperatures should consider the impacts of these conditions on the FLEX equipment and its deployment. From References 4 and 5, Section 2.3.2.2, mean temperatures at the Watts Bar site can reach the upper 70s°F in the summer. Extreme maxima temperature recorded was 108'F at Decatur, Tennessee and 106'F at Chattanooga, Tennessee in the summer.

Therefore, for selection of FLEX equipment the Watts Bar site will consider the site maximumexpected temperatures in their specification, storage, and deployment requirements, including ensuring adequate ventilation or supplementary cooling, if required.

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Key Site assumptions to Provide key assumptions associatedwith implementation of FLEX implement NEI 12-06 Strategies:

strategies. Assumptions are consistent with those detailed in NEI 12-06, Section 3.2.1. Analysis has been performed consistent with the Ref: NEI 12-06 Section 3.2.1 recommendations contained within the Executive Summary of the Pressurized Water Reactor owners group (PWROG) Core Cooling Position Paper (Reference 13) and assumptions from that document are incorporated in the plant specific analytical bases.

NEI 12-06 Assumptions The initial plant conditions are assumed to be the following:

• Prior to the event the reactor has been operating at 100 percent rated thermal power for at least 100 days or has just been shut down from such a power history as required by plant procedures in advance of the impending event.

" At the time of the postulated event, the reactor and supporting systems are within normal operating ranges for pressure, temperature, and water level for the appropriate plant condition. All plant equipment is either normally operating or available from the standby state as described in the plant design and licensing basis.

The following initial conditions are to be applied:

• No specific initiating event is used. The initial condition is assumed to be a loss of offsite power (LOOP) at a plant site resulting from an external event that affects the off-site power system either throughout the grid or at the plant with no prospect for recovery of off-site power for an extended period. The LOOP is assumed to affect all units at a plant site.

• All installed sources of emergency on-site ac power and station blackout (SBO) Alternate ac power sources are assumed to be not'available and not imminently recoverable.

• Cooling and makeup water inventories contained in systems or structures with designs that are robust with respect to seismic events, floods, and high winds, and associated missiles are available.

• Normal access to the ultimate heat sink (UHS) is lost, but the water inventory in the UHS remains available and robust piping connecting the UHS to plant systems remains intact. The motive force for UHS flow, i.e., pumps, is assumed to be lost with no prospect for recovery.

• Fuel for FLEX equipment stored in structures with designs which are robust with respect to seismic events, floods and high winds and associated missiles, remains available.

" Permanent plant equipment that is contained in structures with designs that are robust with respect to seismic events, floods, and high winds, and associated missiles, are available.

• Other equipment, such as portable ac power sources, portable back up dc power supplies, spare batteries, and equipment for 50.54(hh)(2), may be used provided it is reasonably protected from the applicable external hazards per Sections 5 through 9 and Section 11.3 of NEI 12-06 and has predetermined hookup strategies with appropriate procedures/guidance and the equipment is stored in a relative close vicinity of the site.

" Installed electrical distribution system, including inverters and battery chargers, remain available provided they are protected consistent with current station design.

• No additional events or failures are assumed to occur immediately prior to or during the event, including security events.

" Reliance on the fire protection system ring header as a water source is acceptable only if the E-5

header meets the criteria to be considered robust with respect to seismic events, floods, and high winds, and associated missiles.

The following additional boundary conditions are applied for the reactor transient:

" Following the loss of all ac power, the reactor automatically trips and all rods are inserted.

• The main steam system valves (such as main steam isolation valves, turbine stops, atmospheric dumps, etc.), necessary to maintain decay heat removal functions operate as designed.

• Safety/Relief Valves (S/RVs) or Power Operated Relief Valves (PORVs) initially operate in a normal manner if conditions in the reactor coolant system (RCS) so require. Normal valve reseating is also assumed.

" No independent failures, other than those causing the extended loss of alternating current (ac) power (ELAP)/loss of normal access to the ultimate heat sink (LUllS) event, are assumed to occur in the course of the transient.

Sources of expected pressurized water reactor (PWR) reactor coolant inventory loss include:

• Normal system leakage

• Losses from letdown unless automatically isolated or until isolation is procedurally directed

• Losses due to reactor coolant pump (RCP) seal leakage (rate is dependent on the (RCP) seal design)

The initial spent fuel pool (SFP) conditions are:

• All boundaries of the SFP are intact, including the liner, gates, transfer canals, etc.

• Although sloshing may occur during a seismic event, the initial loss of SFP inventory does not preclude access to the refueling deck around the pool.

• SFP cooling system is intact, including attached piping.

• SFP heat load assumes the maximum design basis heat load for the site.

Containment Isolation Valves:

• It is assumed that the containment isolation actions delineated in current SBO coping capabilities is sufficient.

Assumptions Specific to Watts Bar Site Al. The condensate storage tanks (CSTs) and associated piping are not seismically qualified or hardened against missiles and tornados. Watts Bar will either modify the CST such that it will be qualified to be robust with respect to high winds and seismic events or construct an alternate seismic and missile protected CST. Throughout this document, several strategies refer to the use of the CSTs as a suction source. However, these strategies will also apply to the use of a new alternate seismic and missile protected CST, as it is intended for this tank to be constructed within close proximity of the current CSTs. Therefore, this document will only refer to the current CSTs in the strategy descriptions. In addition, it is assumed that piping analysis will be performed to ensure that either of these tanks will not leak out through the piping and can be credited.

A2. Watts Bar Unit I is a mirror image of Unit 2, with only minor differences existing between E-6

plants. For this reason, any sections or sketches which are only shown for a single unit would be directly analogous to the other unit.

A3. The design hardened connections added for the purposes of FLEX are protected against external events or are established at multiple and diverse locations.

A4. Flood and seismic re-evaluations pursuant to the Title 10 of the Code of Federal Regulations (10 CFR) 50.54(f) letter of March 12, 2012 are not completed and therefore not assumed in this submittal. As the re-evaluations are completed, appropriate issues will be entered into the corrective action program.

A5. Required staffing levels will be determined consistent with guidance contained in NEI 12-06 for each of the site specific FLEX strategies. Assumed available staffing levels will be determined consistent with NEI 12-01, as described below.

A. Post event time: 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> - No site access. This duration reflects the time necessary to clear roadway obstructions, use different travel routes, mobilize alternate transportation capabilities (e.g., private resource providers or public sector support), etc.

B. Post event time: 6 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> - Limited site access. Individuals may access the site by walking, personal vehicle or via alternate transportation capabilities (e.g., private resource providers or public sector support).

C. Post event time: 24+ hours - Improved site access. Site access is restored to a near-normal status and/or augmented transportation resources are available to deliver equipment, supplies and large numbers of personnel.

Staffing levels will be assessed to confirm this assumption, or adjustments will be made to plant staffing or FLEX design to meet this requirement.

A6. Watts Bar will design one new storage location to protect portable FLEX equipment against all five external hazards. This location is referred to in this document as the FLEX equipment storage building (FESB). If equipment will be stored in another location for a particular function, it is noted in the section for that function.

A7. Considerations for exceptions to the site security plan or other license/site specific requirements will be included in the FLEX support guidelines.

A8. In the event of a flood scenario, pumps will be staged on the Auxiliary Building roof, which will require cranes or alternate equipment to be available to move equipment.

A9. Instrumentation on FLEX equipment will be used to confirm continual performance.

Al0.This plan defines strategies capable of mitigating a simultaneous loss of all alternating current (ac) power and loss of normal access to the ultimate heat sink resulting from a beyond-design-basis event by providing adequate capability to maintain or restore core cooling, containment, and SFP cooling capabilities at all units on a site. Though specific strategies are being developed, due to the inability to anticipate all possible scenarios, the strategies are also diverse and flexible to encompass a wide range of possible conditions.

These pre-planned strategies developed to protect the public health and safety will be incorporated into the unit emergency operating procedures in accordance with established EOP change processes, and their impact to the design basis capabilities of the unit evaluated under 10 CFR 50.59. The plant Technical Specifications contain the limiting conditions for normal unit operations to ensure that design safety features are available to respond to a design basis accident and direct the required actions to be taken when the limiting conditions are not met. The result of the beyond-design-basis event may place the plant in a condition E-7

where it cannot comply with certain Technical Specifications and/or with its Security Plan, and as such, may warrant invocation of 10 CFR 50.54(x) and/or 10 CFR 73.55(p) (Reference 12)

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Extent to which the guidance, Include a description of any alternativesto the guidance, and JLD-ISG-2012-01 and NEI 12- provide a milestone schedule ofplanned action.

06, are being followed.

Identify any deviations to JLD-ISG-2012-01 and NEI 12-06.

Ref: JLD-ISG-2012-01 Ref: NEI 12-06 Section 13.1 Watts Bar Nuclear plans to fully comply with the guidance in JLD-ISG-2012-01 (Reference 3) and NEI 12-06 (Reference 2) in implementing FLEX strategies for the Watts Bar site.

Provide a sequence of events Strategies that have a time constraintto be successful should be and identify any time identified with a technical basis and ajustificationprovided that constraint required for success the time can reasonably be met (for example, a walkthrough of including the technical basis deployment).

for the time constraint.

Describe in detail in this section the technical basisfor the time constraintidentified on the sequence of events timeline Attachment ]A Ref: NEI 12-06 Section 3.2.1.7 See attachedsequence of events timeline (Attachment ]A).

JLD-ISG-2012-01 Section 2.1 Technical Basis Support information, see attachedNSSS Significant Reference Analysis Reconciliation Table (Attachment IB)

The sequence of events and any associated times constraints are identified below for Watts Bar Reactor Core Cooling and Heat Removal (steam generators available) strategies for FLEX Phases 1 through Phase 3. See attached sequence of events timeline (Attachment 1A) and the technical basis support information in Attachment lB for a summary of this information.

Discussion of action items identified in Attachment 1A table:

1. Initial Load Shed - completed within 45 minutes (0.75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br />) following the start of the event.

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2. Declare ELAP - ELAP entry conditions can be verified by control room staff and it is validated that emergency diesel generators are not available. This step is time sensitive and needs to occur within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> following the start of the event to provide operators with guidance to perform ELAP actions.

3. Extended Load Shed - completed within 90 minutes (1.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />) following the start of the event.

This consists of additional load shedding such that generally, only FLEX required loads remain powered.

4. Debris Removal (Access) - The earliest need for debris removal access paths is to support alignment of the low pressure FLEX pump to the essential raw cooling water (ERCW) headers.

This process will be initiated in order to complete the action prior to deployment depending on the resources available.

5. Watts Bar will develop a post event damage assessment procedure. The damage assessment will evaluate and document the condition of plant systems, structures and components (SSCs) after an ELAP event. The assessment will be consistent with the guidelines contained in supplement 5 of Reference 16.

6. The RCS make-up pump will be aligned from the Boric Acid Tank (BAT) within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> for boration. Plant cooldown commences at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and RCS make-up is required for shrinkage.

This time also allows for adequate boration (Reference 11).

7. Hoses will need to be deployed to the SFP area within 6.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br />. This is the need time based on the SFP time when boil off occurs (Reference 11). This is for an SSE seismic event and an initial bulk water temperature in the pool of 100'F. (Open item 01 8)

8. Venting of the SFP area will need to be completed within 6.9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> based on the SFP time when boil off occurs (Reference 11). This is for an SSE seismic event and an initial bulk water temperature in the pool of 100°F. (Open Item 01 8)

9. Align 225 kVA 480 Vac Generator - the earliest need time for the generator is 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, when it will be needed to power the battery chargers to power the DC and AC Vital Power System (Reference 11).

10. Delayed plant cooldown will commence at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following the start of the event. It must be completed before 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. (Reference 11)

11. Alternate fuel supply will need to be established within 11 hours1.273148e-4 days <br />0.00306 hours <br />1.818783e-5 weeks <br />4.1855e-6 months <br />. This accounts for the 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> in which the FLEX equipment fuel supply depletes and the deployment time. This is an assumption and will need to be assessed for a more exact basis once all FLEX equipment has been purchased and equipment specifications are known (Open item 01 3) (Reference 11).

12. The CST will be depleted in 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br />, at which time the turbine driven auxiliary feedwater pump (TDAFWP) suction will be realigned to the ERCW headers to extend core cooling by use of standing water in the headers (Reference 11).

13. Acceptable control room lighting will be planned to be established for long term support. This is not a time constraint as control room lighting is available via batteries, and portable lighting will be available for necessary activities (Reference 11).

14. The CST will be depleted in 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> and the standing water in the ERCW headers will deplete in 4.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />. The low pressure FLEX pump will need to be aligned to the ERCW headers to provide charging prior to both of these sources depleting (Reference 11). Boration from the BAT will be finished by 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Makeup source is then switched to the refueling water storage tank (RWST) for flooded conditions for long term inventory control (Reference 11).

15. The make-up pump to the steam generators will need to be aligned within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. While the TDAFWP is not anticipated to fail, a backup pump will be staged as soon as feasible (Reference 11).

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16. The Vital Battery and Switchgear room heating, ventilation, and air conditioning (HVAC) study determined that ventilation is not required. until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the ELAP event; at which point it can be monitored periodically, if needed (Open item 01 11) (Reference 14).

17. The Main control room HVAC study determined that ventilation is not required until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into ELAP event; at which point it can be monitored periodically if needed (Open item 01 11)

(Reference 14).

18. The TDAFWP room HVAC study determined that ventilation is not required until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into ELAP event; at which point it can be monitored periodically if needed (Open item 01 11)

(Reference 14).

19. A time of 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> is assumed to align the mobile water purification system to provide clean water to refill the CST. However, ERCW supply is available to be provided indefinitely (Reference 11).

20. The SFP makeup via the ERCW headers will need to be aligned within 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br />. This is based on the time when boil off decreases the water level to 10 feet above the SFP racks, determined in analyses contained in Reference 11 (Open Item 01 8).

21. The mobile boration unit from the regional response center (RRC) will need to be aligned within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. This is based on analysis timeline values (Reference 11).

22. Large generators will need to be aligned within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, this is based on the eventual loss of capability to support steam generator (SG) feed strategy (Reference 11).

23. Large fuel truck service will need to be established within 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. This is based on the depletion of on-site supplies and supplying larger equipment (Reference 11).

To confirm the times given above, Watts Bar will prepare procedures for each task, perform time study walkthroughs for each of the tasks under simulated ELAP conditions, and account for equipment tagging and other administrative procedures required to perform the task. In addition, an evaluation on the impact of FLEX response actions on design basis flood mode preparations will be performed. This evaluation will include the potential for extended preparation time for FLEX. (Open Item 0113)

Identify how strategies will be Describe how the strategies will be deployed in all modes.

deployed in all modes.

Ref: NEI 12-06 section 13.1.6 Deployment of FLEX equipment is described for each FLEX function in the subsequent sections below and covers all operating modes. The broad-spectrum deployment strategies do not change for the different operating modes. The deployment strategies from the storage areas to the staging areas are identical and include debris removal, equipment transport, fuel transport, and power sources and requirements. RCS makeup connections are provided for the higher flow rates required during core cooling with SGs unavailable. Each of these strategies and the associated connection points are described in detail in the subsequent sections. The electrical coping strategies are the same for all modes. Figure A3-29 shows a visual representation of the deployment strategy.

E-1 0

Provide a milestone schedule.

This schedule should include:

• Modifications timeline o Phase 1 Modifications o Phase 2 Modifications o Phase 3 Modifications

" Procedure guidance development complete o Strategies o Maintenance

" Storage plan (reasonable protection)

• Staffing analysis completion

• FLEX equipment acquisition timeline

" Training completion for the strategies

• Regional Response Centers operational Ref: NEI 12-06 Section 13.1 The dates specifically required by the order are obligated or committed dates. Other dates are planned dates subject to change. Updates will be provided in the periodic (six month) status reports.

See attached milestone schedule Attachment 2.

Identify how the programmatic controls will be met.

Ref: NEI 12-06 Section 11 JLD-ISG-2012-01 Section 6.0 Equipment associated with these strategies will be procured as commercial equipment with design, storage, maintenance, testing, and configuration control in accordance with NEI 12-06 Rev. 0 Section 11.

The unavailability of equipment and applicable connections that directly performs a FLEX mitigation strategy will be managed using plant equipment control guidelines developed in accordance with NEI E-11

12-06 Rev. 0 Section 11.5.

Programs and controls will be established to assure personnel proficiency in the mitigation of beyond-design-basis events is developed and maintained in accordance with NEI 12-06 Rev. 0 Section 11.6.

The FLEX strategies and basis will be maintained in an overall program document. Existing plant configuration control procedures will be modified to ensure that changes to the plant design, physical plant layout, roads, buildings, and miscellaneous structures will not adversely impact the approved FLEX strategies in accordance with NEI 12-06 Rev. 0 Section 11.8.

Procedure Guidance Watts Bar is a participant in the PWROG project PA-PSC-0965 and will implement the FLEX Support Guidelines (FSGs) in a timeline to support the implementation of FLEX by the time of the Unit 2 startup. The PWROG has generated these guidelines in order to assist utilities with the development of site-specific procedures to cope with an ELAP in a manner compliant with the requirements of Reference NEI 12-06.

The proposed implementation strategy aligns with the procedure hierarchy described in NEI 12-06 in that actions that maneuver the plant are contained within the typical controlling procedure, and the FSGs are implemented as necessary to maintain the key safety functions of Core Cooling, Spent Fuel Cooling, and Containment in parallel with the controlling procedure actions. The overall approach is symptom-based, meaning that the controlling procedure actions and FSGs are implemented based upon actual plant conditions.

Watts Bar will continue participation in PA-PSC-0965 and will update plant procedures upon the completion of the PWROG program. It is anticipated that the following FSGs will be incorporated into plant procedures in order to develop the FSG interface:

• Alternate auxiliary feedwater (AFW) Suction Source

• Alternate Low Pressure Feedwater

• ELAP direct current (dc) Load Shed/Management

• Initial Assessment and FLEX Equipment Staging

• Alternate CST Makeup

• Loss of dc Power

• Alternate RCS Boration

• Long Term RCS Inventory and Temperature Control

• Passive RCS Injection Isolation

• Alternate SFP Makeup and Cooling

• Alternate Containment Cooling

• Transition from FLEX Equipment Maintenance and Testing The FLEX mitigation equipment will be initially tested (or other reasonable means used) to verify performance conforms to the limiting FLEX requirements. It is expected the testing will include the equipment and the assembled sub-systems to meet the planned FLEX performance. Additionally, Watts Bar will implement the maintenance and testing template upon issuance by the Electric Power Research Institute (EPRI). The template will be developed to meet the FLEX guidelines established in Section 11.5 of Reference 2.

Staffing E-12

The FLEX strategies documented in the event sequence analysis (as summarized in Reference 11) assume:

" On-site staff are at administrative minimum shift staffing levels,

• No independent, concurrent events, and

• All personnel on-site are available to support site response Watts Bar will have to address staffing considerations in accordance with Reference 2 to fully implement FLEX at the site.

Configuration Control Per NEI 12-06 and the Interim Staff Guidance (ISG), the FLEX strategies must be maintained to ensure future plant changes do not adversely impact the FLEX strategies.

Therefore, Watts Bar will maintain the FLEX strategies and basis in an overall program document and will modify existing plant configuration control procedures to ensure changes to the plant design, physical plant layout, roads, buildings, and miscellaneous structures will not adversely impact the approved FLEX strategies.

Describe training plan Training plans will be developed for plant groups su~h as the emergency response organization (ERO), Fire, Security, Emergency Preparedness (EP), Operations, Engineering, Mechanical Maintenance, and Electrical Maintenance. The training plan development will be done in accordance with Watts Bar procedures using the Systematic Approach to Training, and will be implemented to ensure that the required Watts Bar staff is trained prior to implementation of FLEX.

Describe Regional Response The nuclear industry will establish two RRCs to support utilities Center plan during beyond design basis events. Each RRC will hold five sets of equipment, four of which will be able to be fully deployed when requested, the fifth set will have equipment in a maintenance cycle. Equipment will be moved from an RRC to a local Assemble Area, established by the Strategic Alliance for FLEX Emergency Response (SAFER) team and TVA.

Communications will be established between Watts Bar and the SAFER team and required equipment moved to the site as needed. First arriving equipment, as established during development of Watts Bar's playbook, will be delivered to the site within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> from the initial request.

TVA will establish a contract with the SAFER team in accordance with the requirements of Section 12 of Reference 2 (01 17).

Watts Bar will determine where Phase 3 equipment will be staged (Open Item 01 5).

E-1 3

Notes:

1. Maintenance and testing, configuration control, training, and regional response center plans are currently being developed.

E-14

Maintain Core Cooling & Heat Removal Determine Baseline coping capability with installed coping' modifications not including FLEX modifications, utilizing methods described in Table 3-2 of NEI 12-06:

" AFW/EFW

• Depressurize SG for Makeup with Portable Injection Source

" Sustained Source of Water Ref: JLD-ISG-2012-01 Sections 2 and 3 PWR Installed Equipment Phase 1 Core Cooling with SGs Available The coping strategy is to remove heat from the RCS by providing cooling water to the four SGs. The plant is assumed to be operating at full power at the start of the event. An SBO occurs to start the scenario and all ac power is assumed to be lost. The TDAFWP will start as designed and provide cooling through the SGs.

Initial alignment of the TDAFWP suction is to the CST. Analysis shows that each of the current CSTs has a minimum volume of 200,000 gallons, as summarized in Reference 11. One of these tanks would provide approximately 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of inventory to the suction of the TDAFWP at a single unit before the CST is depleted.

When the CST is depleted, suction flow to the TDAFWP can be provided by standing water in the ERCW header, for an additional 4.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />, as summarized in Reference 11.

Core Cooling with SGs Not Available Reactor core cooling and heat removal with SGs not available is provided during Phase 1 by heating up and boiling of the RCS coolant inventory. The lowest allowed level in the RCS, when SGs are not available to provide core cooling, is not more than one foot below the vessel flange during the removal of the reactor vessel head.

RCS inventory during Phase 1 may be maintained by gravity feed from the RWST at each unit. The ability of the RWST at each unit to provide a gravity feed to the RCS is limited by the RWST fluid height, line losses through the gravity feed path, and pressure within the RCS.

If it is determined that gravity feed is not effective to cool the RCS and prevent fuel damage, Watts Bar will take actions to proceduralize administrative controls to pre-stage FLEX equipment prior to entering a condition where the SGs cannot provide adequate core cooling. (Open Item 01 12)

Details:

Coping modifications consist of modifications installed to increase initial coping time, i.e., generators to preserve vital instruments or increase operating time on battery powered equipment.

E-1 5

Provide a brief description Confirm that procedure/guidanceexists or will be developed to support of Procedures / Strategies / implementation.

Guidelines SBO Emergency Operating Instruction (EOI) 1-ECA-0.0 (Reference 17) currently addresses implementation of this strategy. The strategies in 1-ECA-0.0 will be supported by the appropriate FSG for this strategy, when the FSG is developed.

Identify Modifications List modifications and describe how they support coping time.

1.Modifications that are required for the CSTs are discussed in the Key Site Assumptions (Open Item 01 1).

Key Reactor Parameters 1. SG Wide Range Level or Narrow Range Level with AFW Flow indication

2. SG Pressure

3. CST Level RCS instrumentation that is assumed to also be available for this function:

1. Core Exit Thermocouple (CET) Temperature**

2. RCS Hot Leg (HL) Temperature (Thor) if CETs not available

3. RCS Cold Leg (CL) Temperature (Tcold)*

4. RCS Wide Range Pressure

5. Pressurizer Level

6. Reactor Vessel Level Indicating System (RVLIS) (backup to Pressurizer level) - available for up to 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> for limiting flood scenario, at which point pressurizer level is available again.

7. Neutron Flux For all instruments listed above the normal power source and the long-term power source are the 125 Vdc Vital Battery.

• This instrumentation is only available until flood water enters the auxiliary instrument room. The potential, validating indicator for Tcold is SG pressure when natural circulation is occurring. This substitution is allowed by guidance provided in Reference 16.

• • This instrumentation is only available until flood water enters the auxiliary instrument room (01 15). The potential validating indicator for CETs is RCS HL. This substitution is allowed by guidance provided in Reference 16.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

E-16

Notes:

1. Core cooling strategies are provided for conditions where SGs are available or where SGs are not available but a sufficient RCS vent has been established to support core cooling. This assumption is per the guidance of NEI 12-06 FAQ 2012-19. Other configurations are not considered as these occur at short durations that are exempted per NEI- 12-06 Table D.

E-1 7

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 2 Provide,a general description of the coping strategies using on-site portable equipment includingstation modifications that are proposedto maintain core cooling. Identify methods and strategy(ies) utilized to achieve this coping time.

Core Cooling with SGs Available Transition to Phase 2 is required before the CST inventory and standing water in the ERCW headers is depleted at 14.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />, as summarized in Reference 11.

To provide an unlimited supply of water for core cooling during Phase 2, a low pressure FLEX pump will be used to pressurize the ERCW headers which can then be used for direct supply to the TDAFWP suction.

Surviving, non-seismic, clean water tanks can also be used to refill the CST using transfer pumps.

An intermediate pressure FLEX pump will be provided for supplying water to the SGs for core cooling after operating conditions of the TDAFWP cannot be maintained. The intermediate pressure FLEX pump will supply water to the auxiliary feedwater piping downstream of the TDAFWP or Motor Drive Auxiliary Feedwater Pumps (MDAFWP). The intermediate pressure FLEX pump staging location for non flood conditions is near the CST which is the suction source for this condition. The intermediate pressure FLEX pump is moved to the Auxiliary Building roof during preparation for flood conditions and the suction source is from the ERCW headers or flood waters. The storage locations, deployment paths and staging locations for the FLEX equipment are provided in Attachment 3.

For non-flood conditions, Watts Bar will gradually transition to a long term core cooling strategy. This will include the use of the low pressure FLEX pump on-site to provide flow to the component cooling system (CCS) heat exchanger and the on-site 3 megawatt (MW) diesel generator (DG) torepower both the CCS and residual heat removal (RHR) pumps. As the 3 MW DGs are not required to support the coping strategies, but rather long-term cooling strategies, additional details are not included in this submittal.

For flood conditions, the RHR pumps may be underwater, depending on the severity of the flood. In this scenario, the plant would continue supplying water to the SGs using the intermediate pressure FLEX pump supplied by water from the ERCW headers or flood waters.

Core Cooling with SGs Not Available For an event that occurs with a unit in core cooling with SGs not available, the transition to Phase 2 strategies will be required as inventory is lost from the RCS. Reactor core cooling and heat removal with SGs not available will be provided by using the intermediate pressure FLEX pump to inject water into the intermediate safety injection system.

Core cooling is maintained through heat removal from the RCS via coolant boil off. Prior to loss of gravity feed from the RWST, the intermediate pressure FLEX pump must be aligned to take suction from the RWST or another acceptable alternate coolant source and deliver the coolant to the vessel.

The connections utilized for RCS Inventory Control/Long-Term Sub criticality will also be utilized for the reactor core cooling and heat removal with steam generators not available strategies (Modes 5 and 6). These E-1 8

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 2 connections are described in the RCS inventory control section. In addition, a flushing flow of 123 gpm at atmospheric conditions is required at 70 hours8.101852e-4 days <br />0.0194 hours <br />1.157407e-4 weeks <br />2.6635e-5 months <br /> in order to preclude the RCS fluid from the incipient boric acid precipitation point.

Details:

Provide a brief description Confirm that procedure/guidanceexists or will be developed to support of Procedures / Strategies / implementation with a description of the procedure/ strategy/ guideline.

Guidelines Procedures and guidance to support deployment and implementation, including interfaces to EOPs, special event procedures, abnormal event procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance and Watts Bar's strategy aligns with the generic guidance and will consider the Nuclear Steam Supply System (NSSS) specific guidance once available.

Identify Modifications List modifications necessaryfor Phase 2 1.The backup instrument air supply to the SG Atmospheric Relief Valves (ARVs) and Auxiliary Feedwater (AFW) Level Control Valves (LCVs) will be moved to above the probable maximum flood (PMiF) elevation for flood mode response.

2.Connections will be made on the ERCW headers in the Auxiliary Building for supplying water to the intermediate pressure FLEX pump.

3.The primary connection point for SG cooling will be upstream of the SG LCVs on the TDAFWP discharge line.

4.The secondary connection point for SG cooling will be upstream of the SG LCVs in both the train A and train B MDAFWP discharge piping. A connection to both trains is needed for the secondary connection to ensure feed to all four SGs.

5.A new connection to take suction from the CST is required.

6.New connections will be made at the ERCW headers in the Intake Pumping Station (IPS) for the low pressure FLEX pump to pressurize the ERCW headers during non-flood conditions.

7.New connections will be made at the ERCW headers in the 5th Diesel Generator Building for the low pressure FLEX pump to pressurize the ERCW headers during flood conditions.

8.New connections will be made to the Tritiated water storage tank (TWST), Primary Water Storage Tank (PWST), and Demineralized Water Storage Tank (DWST) for transferring water to refill the CST.

Key Reactor Parameters List instrumentationcredited or recoveredfor this coping evaluation.

1. SG Wide Range Level or Narrow Range Level with AFW Flow E-1 9

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 2 indication

2. SG Pressure

3. CST Level RCS instrumentation that is assumed to also be available for this function:

1. CET Temperature**

2. RCS HL Temperature (Thot) if CETs not available

3. RCS CL Temperature (Tcold)*

4. RCS Wide Range Pressure

5. Pressurizer Level

6. RVLIS (backup to Pressurizer level) - available for up to 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> for limiting flood scenario, at which point pressurizer level is available again.

7. Neutron Flux For all instruments listed above the normal power source and the long-term power source are the 125 Vdc Vital Battery.

• This instrumentation is only available until flood water enters the auxiliary instrument room. The potential validating indicator for Tcold is SG pressure when natural circulation is occurring. This substitution is allowed by guidance provided in Reference 16.

• • This instrumentation is only available until flood water enters the auxiliary instrument room (01 15). The potential validating indicator for CETs is RCS HL. This substitution is allowed by guidance provided in Reference 16.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

Storage / Protection of Equipment:

Describe storage protection plan or schedule to determine storage requirements Seismic Portable equipment required to implement this FLEX strategy will be maintained in the FESB, which will be designed for seismic loading in excess of the minimum requirements of American Society of Civil E-20

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 2 T

Engineers (ASCE) 7-10. The design of the FESB provides a minimum High Confidence of Low Probability Failure (HCLPF) of 2x SSE.

Flooding Portable equipment required to implement this FLEX strategy will be maintained in the FESB, which is sited in a suitable location that is above Note: if stored below current flood level, the PMF level and as such is not susceptible to flooding from any source.

then ensure procedures exist to move equipment prior to exceeding flood level.

Severe Storms with High Portable equipment required to implement this FLEX strategy will be Winds maintained in the FESB, which is designed to meet or exceed the licensing basis high wind hazard for Watts Bar.

Snow, Ice, and Extreme Cold The FESB will be evaluated for snow, ice and extreme cold temperature effects and heating will be provided as required to assure no adverse effects on the FLEX equipment. The FESB will have a standalone HVAC system.

High Temperatures The FESB will be evaluated for high temperature effects and ventilation will be provided as required to assure no adverse effects on the FLEX equipment. The FESB will have a standalone HVAC system.

Deployment Conceptual Design The figures provided in Attachment 3 show the deployment paths from each of the storage locations to the staging locations.

Strategy Modifications Protection of connections Identify Strategy includinghow Identify Modifications Identify how the connection is the equipment will be deployed to protected the point of use.

SGs Available Primary connection modifications: All FLEX equipment and connection points will be designed The primary connection for the 9 A tee will be added to the to meet or exceed Watts Bar intermediate pressure FLEX pump TDAFWP discharge line. design basis SSE protection will be located in the steam valve

• An isolation valve will be requirements.

room on Elevation 729' upstream added to the main line E-21

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 2 of the LCVs on the TDAFWP upstream of connection. The primary connection is located discharge piping.

• An isolation valve will be inside the Auxiliary Building. The added to the new branch. Auxiliary Building is a safety For this alignment during non-

• Storz cap/adapter will be related structure and is protected flood conditions, suction to the added to new branch. from all external hazards except intermediate pressure pump will flooding. For flood conditions, be taken from the CST or ERCW CST modifications: procedures will ensure that hoses headers. During flood conditions, are connected before flood levels suction will be taken from the A Storz hose connection will be reach the connection.

ERCW headers or a submersible added to the existing valve at the pump supplying flood water. bottom of each CST. The connections to the CST and Discharge of the intermediate ERCW will be seismically pressure pump will be to the ERCW modifications: qualified and missile protected.

connection points shown in For connections required during , Figure A3-1. The For non-flood conditions, the low flood conditions, procedures will proposed hose routing for the pressure FLEX pump will be ensure that hoses are connected primary connection and the staged next to the IPS. The before flood levels reach the associated equipment staging area existing ERCW piping in the IPS connection.

can be found in Attachment 3, must be modified to add isolation Figures A3-3 and A3-4. valves with hose connections to Connections to other tanks are not allow the ERCW headers to be protected since the connections are ERCW connections can be found pressurized. to non-protected tanks and would in Attachment 3, Figures A3-26 only be available if the tank and A3-27. For flood conditions, the low survives the event. These pressure FLEX pump will be connections are used to provide staged next to the 5h Diesel additional capability above the Generator Building. The existing minimum FLEX requirements.

ERCW piping inside the 5h Diesel Generator Building will be modified to add isolation valves with hose connections to allow the ERCW headers to be pressurized.

To supply water to the suction of the intermediate pressure FLEX pump, existing ERCW headers cleanout ports in the Auxiliary Building will be utilized. The cleanout ports must be modified to add a Storz hose connection.

Other tank modifications E-22

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 2 An isolation valve and Storz hose connections will be added to the TWST, PWST, and DWST for use of water transfer pumps to provide water to refill the CST or direct supply.

SGs Available Secondary connentinn All FLEX equipment and modifications: connection points will be designed The secondary connection will be to meet or exceed Watts Bar located in the Auxiliary Building " Hard piping will be installed design basis SSE protection on Elevation 737' upstream of the between the high pressure fire requirements.

LCVs on the MDAFWP discharge protection (HPFP) Train A piping. and Train B flood conditions The secondary connection is supply piping and the located inside the Auxiliary For this alignment, suction will be MDAFWP Train A and Train Building. The Auxiliary Building taken from the CST or ERCW and B piping which will replace is a safety related structure and is discharged through the the existing removable spool protected from all external hazards intermediate pressure FLEX piece. except flooding. For flood pumps to the connection points

• A tee will be added to this conditions, procedures will ensure shown in Attachment 3, Figure piping. that hoses are connected before A3-2. The proposed hose routing

• Add isolation valve to either flood levels reach the connection.

for the secondary connection and side of new tee.

the associated equipment staging " Add isolation valve on new The connections to the CST and area can be found in Attachment 3, branch. ERCW will be seismically Figures A3-3 and Figures A3-5

• Storz cap/adapter will be qualified and missile protected.

through A3-8. added to new branch. For connections required during flood conditions, procedures will ERCW connections can be found CST. ERCW. and other tank ensure that hoses are connected in Attachment 3, Figures A3-26 modifications: before flood levels reach the and A3-27. connection.

Same as primary.

Connections to other tanks are not protected since the connections are to non-protected tanks and would only be available if the tank survives the event. These connections are used to provide additional capability above the minimum FLEX requirements.

Steam Generators Not Available Primary Connection Modification All FLEX equipment and connection points will be designed E-23

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 2 When SGs are not available, 0 Install tee or weldolet, to meet or exceed Watts Bar suction will be taken from the S Add two isolation valves design basis SSE protection RWST and discharged through the 0 Add a hose adapter requirements.

intermediate pressure FLEX BAT Modification pumps staged near the RWST

• Install tees on discharge lines The primary connection and BAT connection to the primary connection are located inside the of BAT A.

connection point.

• Add an isolation valve on the Auxiliary Building. The Auxiliary Building is a safety related branch.

" Add a Storz adapter with cap structure and is protected from all external hazards except flooding.

on branch.

For flood conditions, procedures will ensure that hoses are RWST modifications:

connected before flood levels reach the connection.

A connection attached to manhole at the bottom of each RWST with The RWST connection will be one isolation valve.

seismically qualified and missile protected. For connections required during flood conditions, procedures will ensure that hoses are connected before flood levels reach the connection.

SGs Not Available The secondary connection All FLEX equipment and modification for steam generators connection points will be designed When SGs are not available, not available is identical to the to meet or exceed Watts Bar suction will be taken from the primary, except for on safety design basis SSE protection RWST and discharged through the injection pump (SIP) Train B requirements.

intermediate pressure FLEX discharge.

pumps staged near the RWST The secondary connection and connection to the secondary BAT and RWST Modification BAT connection are located inside connection point. Same as primary. the Auxiliary Building. The Auxiliary Building is a safety related structure and is protected from all external hazards except flooding. For flood conditions, procedures will ensure that hoses are connected before flood levels reach the connection.

The RWST connection will be seismically qualified and missile protected. For connections E-24

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 2 required during flood conditions, procedures will ensure that hoses are connected before flood levels reach the connection.

Notes:

1. System modifications are described in the "Modifications" section above and are illustrated in Attachment 3.

2. Figures A3-3 through A3-8 in Attachment 3 provides the deployment routes from the staging locations for each Intermediate pressure FLEX pump to the pump suction source and to the primary and secondary connection points on the AFW system.

3. Core cooling strategies are provided for conditions where SGs are available or where SGs are not available but a sufficient RCS vent has been established to support core cooling. This assumption is per the guidance of NEI 12-06 FAQ 2012-19. Other configurations are not considered as these occur at short durations that are exempted per NEI- 12-06 Table D.

E-25

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 3 Provide a generaldescription of the coping strategies usingphase 3 equipment includingmodifications that areproposedto maintaincore cooling. Identify methods and strategy(ies) utilized to achieve this coping time.

Core Cooling with SGs Available For Phase 3, Watts Bar will continue the Phase 2 coping strategies with additional assistance provided from offsite equipment/resources. Backup or alternate Phase 2 FLEX equipment will be provided by the RRC as necessary. Additionally, purification of water at each unit will be supported by a mobile water purification unit from the RRC. This unit will process water from the Tennessee River or other raw water sources to remove particulate and demineralize the water. The purification equipment will have an internal pump and be locally powered by diesel fuel. This water would then be used to refill the CST.

Core Cooling with SGs Not Available Reactor core cooling with SGs not available is adequately maintained via the Phase 2 strategy; however, borated sources are limited. Phase 3 deployment of a unit capable of generating borated water from the water processed through the purification unit can further extend coping times with respect to RCS inventory management.

Watts Bar will determine where Phase 3 equipment will be staged (Open item 01 5).

Details:

Provide a brief description Procedures and guidance to support deployment and implementation, of Procedures / Strategies /

including interfaces to EOPs, special event procedures, abnormal event Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available.

Finally, Watts Bar will include in procedures notification of the RRC to arrange for delivery and deployment of off-site equipment and sufficient supplies of commodities.

Identify Modifications Each of the Phase 3 strategies will utilize common connections as described for the Phase 2 connections to prevent any compatibility issues with the offsite equipment.

Key Reactor Parameters List instrumentationcredited or recoveredfor this coping evaluation.

1. SG Wide Range Level or Narrow Range Level with AFW Flow indication E-26

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 3

2. SG Pressure

3. CST Level RCS instrumentation that is assumed to also be available for this function:

1. CET Temperature**

2. RCS HL Temperature (Thot) if CETs not available

3. RCS CL Temperature (TcoId)*

4. RCS Wide Range Pressure

5. Pressurizer Level

6. RVLIS (backup to Pressurizer level) - available for up to 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> for limiting flood scenario, at which point pressurizer level is available again.

7. Neutron Flux For all instruments listed above the normal power source and the long-term power source are the 125 Vdc Vital Battery.

• This instrumentation is only available until flood water enters the auxiliary instrument room. The potential validating indicator for Tcold is SG pressure when natural circulation is occurring. This substitution is allowed by guidance provided in Reference 16.

• • This instrumentation is only available until flood water enters the auxiliary instrument room (01 15). The potential validating indicator for CETs is RCS HL. This substitution is allowed by guidance provided in Reference 16.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

Deployment Conceptual Design Strategy Modifications Protection of connections Identify Strategy includinghow Identify Modifications Identify how the connection is the equipment will be deployed to E-27

Maintain Core Cooling & Heat Removal PWR Portable Equipment Phase 3 the point of use. protected All FLEX equipment and A mobile water purification Each of the Phase 3 strategies will All FLEX eipme and system will enable water from the utilize common connections as connet oi wilee to meet or exceed Watts Bardesigne Tennessee River or other raw described for the Phase 2 water source to be purified. This connections to prevent any design basis SSE protection unit would process the water compatibility issues with the requirements.

source and discharge improved offsite equipment. The system will take suction quality water to the CST. This unit would have an internal pump The from the Take Rion directly from the Tennessee River and be locally powered. or other raw water source. The discharge connections will be identical to the ones used for Phase 2. The protection of those connection points is described in the section for Phase 2.

Notes:

1. Core cooling strategies are provided for conditions where Steam Generators are available or where Steam Generators are not available but a sufficient RCS vent has been established to support core cooling. This assumption is per the guidance of NEI 12-06 FAQ 2012-19.

Other configurations are not considered as these occur at short durations that are exempted per NEI-12-06 Table D.

E-28

Maintain RCS Inventory Control Determine Baseline coping capability with installed coping 2 modifications not including FLEX modifications, utilizing methods described in Table 3-2 of NEI 12-06:

• Low Leak RCP Seals or RCS makeup required

• All Plants Provide Means to Provide Borated RCS Makeup PWR Installed Equipment Phase 1:

Provide a generaldescription of the coping strategies using installed equipment includingmodifications that areproposedto maintain RCS inventory control. Identify methods (Low Leak RCP Seals and/or boratedhigh pressure RCS makeup) and strategy(ies) utilized to achieve this coping time.

This section discusses RCS inventory control and subcriticality issues for conditions where SGs are available. RCS inventory control and subcriticality issues for conditions where SGs are not available are addressed in the reactor core cooling and heat removal section of this report.

Following the declaration of an ELAP, a plant cooldown will be performed at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> after the ELAP. At the time plant cooldown is initiated, a means to borate the RCS is required. Natural circulation is maintained by ensuring adequate RCS inventory.

Watts Bar is installing low leak rate seals which will reduce the potential seal leakage to approximately 1 gpm per RCP. This installation will significantly extend the time when RCS makeup may be required.

Both Unit 1 and Unit 2 will have 4 SHIELD3 seals installed prior to the full implementation of FLEX.

Utilizing WCAP- 17601 methodology (Reference 8), Reference 11 summarizes the limiting plant-specific scenarios for RCS inventory control, shutdown margin, and Mode 5/Mode 6 boric acid precipitation control with respect to the guidelines set forth in NEI 12-06 (Reference 2).

RCS inventory is not a significant concern for the ELAP scenario due to the installation of the low leakage RCP seals (SHIELD). A high pressure FLEX pump would be required approximately 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> after the ELAP to ensure that single phase natural circulation is maintained. However, boration is required prior to 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br />, so inventory will be provided to the RCS prior to the required time.

Details:

2 Coping modifications consist of modifications installed to increase initial coping time, i.e., generators to preserve vital instruments or increase operating time on battery powered equipment.

3 SHIELDis a registeredtrademark of Westinghouse Electric Company LLC in the United States and may be registeredin other countries throughout the world. All rights reserved. Unauthorizeduse is strictly prohibited.

E-29

Maintain RCS Inventory Control Provide a brief description Confirm that procedure/guidance.exists or will be developed to support of Procedures / Strategies / implementation Guidelines SBO EOI I-ECA-0.0 (Reference 17) addresses all procedural guidance required for maintaining RCS inventory during Phase 1. Procedures and guidance to support implementation of a boration strategy, including interfaces to EOPs, special event procedures, abnormal event procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available.

Identify Modifications List modifications

1. Installation of Low-leak RCP Seals (SHIELD)

Key Reactor Parameters List instrumentationcreditedfor this coping evaluation.

1. CET Temperature**

2. RCS HL Temperature (Thot) if CETs not available

3. RCS CL Temperature (Tcowd)*

4. RCS Wide Range Pressure

5. Pressurizer Level

6. RVLIS (backup to Pressurizer level) - available for up to 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> for limiting flood scenario, at which point pressurizer level is available again.

7. Neutron Flux For all instruments listed above the normal power source and the long-term power source are the 125 Vdc Vital Battery.

• This instrumentation is only available until flood water enters the auxiliary instrument room. The potential validating indicator for Tcold is SG pressure when natural circulation is occurring. This substitution is allowed by guidance provided in Reference 16.

• • This instrumentation is only available until flood water enters the auxiliary instrument room (01 15). The potential validating indicator for CETs is RCS HL. This substitution is allowed by guidance provided in Reference 16.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

E-30

Maintain RCS Inventory Control Notes: None E-31

Maintain RCS Inventory Control PWR Portable Equipment Phase 2:

Provide a generaldescription of the coping strategies using on-site portable equipment including modifications that areproposedto maintain RCS Inventory Control. Identify methods(Low Leak RCP Seals and/or boratedhigh pressureRCS makeup)andstrategy(ies) utilized to achieve this coping time.

This section discusses RCS inventory control and subcriticality issues for conditions where SGs are available. RCS inventory control and subcriticality issues for conditions where SGs are not available are addressed in the reactor core cooling and heat removal section of this report.

For boration, a high pressure FLEX pump would be required to be deployed and capable of injecting borated fluid into the RCS just prior to the initiation of the plant cooldown to ensure that sub-criticality is maintained in the core when suction is taken from the BAT. Additionally, a means to ensure that the accumulators will not inject into the RCS, rather than the BAT, will need to be initiated prior to plant cooldown. This can be achieved by either isolating the accumulators prior to plant cooldown, or sizing the high pressure FLEX pump so that the RCS will remain at a pressure at which the accumulators would not inject.

If the external event occurs when SGs are available, the RCS will require makeup beginning at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to maintain adequate boration and makeup for any minor leakage in the system. This function is provided by using a high pressure FLEX pump to supply coolant from the BATs or RWST into existing SIP discharge piping. SIP piping is utilized to supply coolant to the RCS because the system remains at high pressure throughout Phase 2. The electric pump is powered by the 225 kVA 480 Vac DG, which will be aligned prior to when RCS makeup will begin.

Analysis shows that the BATs are available for at least 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> for flood, as summarized in Reference 11.

This is sufficient time to borate the RCS and recover pressurizer level such that RVLIS is not needed when the Auxiliary Building floods. At 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, suction of the RCS pump may need to be switched to the RWST, if the impending flood level is high enough to flood the BATs.

Watts Bar will gradually transition to a long term core cooling strategy. For non-flood conditions, this strategy involves cooling the core with one train of installed RHR equipment, one train of CCS equipment, and using the low pressure FLEX pump to supply water to the CCS heat exchanger. Once this strategy is initiated, the RCS can be fully depressurized and inventory control will no longer be required.

For flood conditions, the strategy is to transition to long term core cooling by continuing to cope using Phase 2 strategies.

Details:

Provide a brief description Procedures and guidance to support deployment and implementation, of Procedures / Strategies / including interfaces to EOPs, special event procedures, abnormal event Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the E-32

Maintain RCS Inventory Control PWR Portable Equipment Phase 2:

generic guidance and will consider the NSSS specific guidance once available.

Identify Modifications List modifications

1. The primary connection will to the SIP Train A discharge piping.

2. The secondary connection will be to the SIP Train B discharge piping.

3. An additional option for a connection point is to the flood mode boration makeup system (FMBMS).

4. A connection will be added to the BAT A discharge line.

5. A connection will be added to each RWST.

6. Installation of Low-leak RCP Seals (SHIELD).

Key Reactor Parameters List instrumentationcreditedor recoveredfor this coping evaluation.

1. CET Temperature**

2. RCS HL Temperature (Thor) if CETs not available

3. RCS CL Temperature (Tcold)*

4. RCS wide range pressure

5. RCS Passive Injection Level

6. Pressurizer Level

7. RVLIS (backup to Pressurizer level) - available for up to 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> for limiting flood scenario, at which point pressurizer level is available again.

8. Neutron Flux For all instruments listed above the normal power source and the long-term power source are the 125 Vdc Vital Battery.

• This instrumentation is only available until flood water enters the auxiliary instrument room. The potential validating indicator for Tcold is SG pressure when natural circulation is occurring. This substitution is allowed by guidance provided in Reference 16.

• • This instrumentation is only available until flood water enters the auxiliary instrument room (01 15). The potential validating indicator for CETs is RCS HL. This substitution is allowed by guidance provided in Reference 16.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

E-33

Maintain RCS Inventory Control PWR Portable Equipment Phase 2:

Storage / Protection of Equipment:

Describe storage / protection plan or schedule to determine storage requirements Seismic In addition to equipment being stored in the FESB (as described in the Reactor Core Cooling and Heat Removal section) for this function, equipment will be stored in the Auxiliary Building, which is seismically qualified.

Flooding In addition to equipment being stored in the FESB (as described in the Reactor Core Cooling and Heat Removal section) for this function, Note: if stored below current flood level, equipment will be stored in the Auxiliary Building. Equipment required then ensure procedures exist to move for this function will be stored so that it can be deployed prior to any equipment prior to exceeding flood level, concerns with flooding.

Severe Storms with High In addition to equipment being stored in the FESB (as described in the Winds Reactor Core Cooling and Heat Removal section) for this function, equipment will be stored in the Auxiliary Building, which is protected from high winds.

Snow, Ice, and Extreme Cold In addition to equipment being stored in the FESB (as described in the Reactor Core Cooling and Heat Removal section) for this function, equipment will be stored in the Auxiliary Building, which is an environmentally controlled building and provides protection from snow, ice, and extreme cold effects.

High Temperatures In addition to equipment being stored in the FESB (as described in the Reactor Core Cooling and Heat Removal section) for this function, equipment will be stored in the Auxiliary Building, which is an environmentally controlled building and provides protection from high temperature effects.

Deployment Conceptual Modification (Attachment 3 contains Conceptual Sketches)

Strategy Modifications Protection of connections Identify Strategy including how Identify Modifications Identify how the connection is the equipment will be deployed protected to the point of use.

E-34

Maintain RCS Inventory Control PWR Portable Equipment Phase 2:

The primary RCS connection Primary Connection Modification All FLEX equipment and will be on the SIP Train A connection points will be designed discharge line, in the SIP room 0 Install tee or weldolet, to meet or exceed Watts Bar at elevation 692'. This 0 Add two isolation valves design basis SSE protection connection is used only during 0 Add a hose adapter requirements.

non-flood conditions.

BAT Modification The primary connection and BAT For this alignment, suction will

• Install tees on discharge lines connection are located inside the be taken from the BATs or of BAT A. Auxiliary Building. The Auxiliary RWST and discharged through

• Add an isolation valve on the Building is a safety related the high pressure FLEX pumps branch. structure and is protected from all to the connection points shown

• Add a Storz adapter with cap external hazards except flooding.

in Attachment 3, Figure A3-9. on branch.

The proposed hose routing for The RWST connection will be the primary connection and the RWST modifications: seismically qualified and missile associated equipment can be protected.

found in Attachment 3, Figures A connection attached to manhole A3-12 through A3-14. at the bottom of each RWST with one isolation valve.

During Mode 5 and 6 with SGs unavailable, suction will be taken from the RWST and discharged through the intermediate pressure FLEX pumps (staged near the RWST connection) to the primary connection point.

The secondary RCS connection The secondary connection All FLEX equipment and will be on the SIP Train B modification is identical to the connection points will be designed discharge line, in the SIP room primary, except for on SIP Train B to meet or exceed Watts Bar at elevation 692'. This discharge. design basis SSE protection connection is used only during requirements.

non-flood conditions. BAT and RWST Modifications Same as primary. The secondary connection and For this alignment, suction will BAT connection are located inside be taken from the BATs or the Auxiliary Building. The RWST and discharged through Auxiliary Building is a safety the high pressure FLEX pumps related structure and is protected to the connection points shown from all external hazards except in Attachment 3, Figure A3-9. flooding.

The proposed hose routing for the secondary RCS FLEX The RWST connection will be E-35

Maintain RCS Inventory Control PWR Portable Equipment Phase 2:

connection and the associated seismically qualified and missile equipment can be found in protected. For connections , Figure A3-12 and required during flood conditions, Figures A3-18 through 20. procedures will ensure that hoses are connected before flood levels During Mode 5 and 6 with SGs reach the connection.

unavailable, suction will be taken from the RWST and discharged through the intermediate pressure FLEX pumps staged near the RWST connection to the secondary connection point.

An additional RCS connection FMBMS Connection Modification All FLEX equipment and (For flood conditions only) will connection points will be designed be at the FMBMS spool piece

• Adapter and hose connection at to meet or exceed Watts Bar flange connection. Spool piece flange connection design basis SSE protection to FMBMS requirements.

For this alignment, the high pressure FLEX pump is staged This connection is located inside on the Auxiliary Building roof. RWST modifications: the Auxiliary Building. The Suction to the pump is provided Auxiliary Building is a safety by a submersible pump lowered

• None. related structure and is protected into the RWST and the pump from all external hazards except discharge is routed to the flooding. The FMBMS FMBMS spool piece flange connection is located above the connection. PMF.

Notes:

1. System modifications are described in the "Modifications" section above and are illustrated in Attachment 3.

2. N high pressure FLEX pumps will be stored in the Auxiliary Building and N high pressure FLEX pumps will be stored in the FESB. This satisfied N+1 NEI requirements.

3. Figures A3-12 through A3-20 ,in Attachment 3 provides the deployment routes from the staging locations for each high pressure FLEX pump to the pump suction piping and to the primary and secondary connection points on the RCS connected systems.

E-36

Maintain RCS Inventory Control PWR Portable Equipment Phase 3:

Provide a general description of the coping strategies using phase 3 equipment including modifications that are proposed to maintain RCS Inventory Control. Identify methods (Low Leak RCP Seals and/or boratedhigh pressure RCS makeup)and strategy(ies) utilized to achieve this coping time.

This section discusses RCS inventory control and subcriticality issues for conditions where SGs are available. RCS inventory control and subcriticality issues for conditions where SGs are not available are addressed in the reactor core cooling and heat removal section of this report.

Reactor level and sub-criticality is adequately maintained via the Phase 2 strategy; however, borated sources are limited. Phase 3 deployment of a unit capable of generating borated water from the water processed through the purification unit can further extend coping times with respect to RCS inventory management.

For Phase 3, Watts Bar will continue the Phase 2 coping strategies with additional assistance provided from offsite equipment/resources. Backup or alternate Phase 2 FLEX equipment will be provided by the RRC as necessary.

Watts Bar will determine where Phase 3 equipment will be staged (Open item 01 5).

Details:

Provide a brief description Procedures and guidance to support deployment and implementation, of Procedures / Strategies / including interfaces to EOPs, special event procedures, abnormal event Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available. Finally, Watts Bar will include in procedures notification of the RRC to arrange for delivery and deployment of off-site equipment and sufficient supplies of commodities.

i Identify Modifications Each of the Phase 3 strategies will utilize common connections as described for the Phase 2 connections to prevent any compatibility issues with the offsite equipment.

Key Reactor Parameters List instrumentationcredited or recoveredfor this coping evaluation.

1. CET Temperature**

2. RCS HL Temperature (Th0t) if CETs not available

3. RCS CL Temperature (Tcold)*

4. RCS wide range pressure

5. RCS Passive Injection Level

6. Pressurizer Level E-37

Maintain RCS Inventory Control PWR Portable Equipment Phase 3:

7. RVLIS (backup to Pressurizer level) - available for up to 27 hours3.125e-4 days <br />0.0075 hours <br />4.464286e-5 weeks <br />1.02735e-5 months <br /> for limiting flood scenario, at which point pressurizer level is available again.

8. Neutron Flux For all instruments listed above the normal power source and the long-term power source are the 125 Vdc Vital Battery.

• This instrumentation is only available until flood water enters the auxiliary instrument room. The potential validating indicator for Tcold is SG pressure when natural circulation is occurring. This substitution is allowed by guidance provided in Reference 16.

• • This instrumentation is only available until flood water enters the auxiliary instrument room (01 15). The potential validating indicator for CETs is RCS HL. This substitution is allowed by guidance provided in Reference 16.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

Deployment Conceptual Modification (Attachment 3 contains Conceptual Sketches)

Strategy Modifications Protection of connections Identify Strategy includinghow Identify Modifications Identify how the connection is the equipment will be deployed protected to the point of use.

A mobile boration system would Each of the Phase 3 strategies will All FLEX equipment and enable borated water to be utilize common connections as connection points will be designed produced using the non-borated described for the Phase 2 to meet or exceed Watts Bar water sources that are available connections to prevent any design basis SSE protection at Watts Bar. This unit would compatibility issues with the requirements.

combine the purified non- offsite equipment. The discharge connections will be borated water from the mobile identical to the ones used for water purification system and Phase 2. The protection of those boron with a mixing mechanism connection points is described in to discharge a desired I E-38

Maintain RCS Inventory Control PWVR Portable Equipment Phase 3:

concentration of borated water, the section for Phase 2 for RCS which could be used to makeup Inventory Control.

to the BATs or RWST. This unit would have an internal pump and be locally powered.

Notes: None E-39

Maintain Containment Determine Baseline coping capability with installed coping 3 modifications not including FLEX modifications, utilizing methods described in Table 3-2 of NEI 12-06:

• Containment Spray

" Hydrogen igniters (ice condenser containments only)

PWR Installed Equipment Phase 1:

Provide a general description of the coping strategies using installed equipment including modifications that are proposed to maintain containment. Identifjy methods (containment spray/Hydrogen igniter) and strategy(ies) utilized to achieve this coping time.

Watts Bar will perform a containment evaluation based on the boundary conditions described in Section 2 of NEI 12-06. Based on the results of this evaluation, required actions to ensure maintenance of containment integrity and required instrumentation function will be developed. (Open item 01 4)

There are no phase 1 actions required at this time that need to be addressed.

Details:

Provide a brief description Procedures and guidance to support implementation of this strategy, of Procedures / Strategies/ including interfaces to EOPs, special event procedures, abnormal event Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available.

Identify Modifications N/A Key Containment List instrumentationcreditedfor this coping evaluation.

Parameters

1. Containment Pressure*

2. Containment Temperature**

• For this instrumentation, the normal power source and the long-term power source are the 125 Vdc Vital Battery.

• • This instrumentation is only available until flood water enters the technical support center (TSC) inverter or station battery rooms. (Open 3 Coping modifications consist of modifications installed to increase initial coping time, i.e., generators to preserve vital instruments or increase operating time on battery powered equipment.

E-40

Maintain Containment item 0110)

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

Notes: None E-41

Maintain Containment PWR Portable Equipment Phase 2:

Provide a general description of the coping strategies using on-site portable equipment including modifications that areproposedto maintain containment. Identify methods (containment spray/hydrogen igniters)and strategy(ies) utilized to achieve this coping time.

Watts Bar will perform a containment evaluation based on the boundary conditions described in Section 2 of NEI 12-06. Based on the results of this evaluation, required actions to ensure maintenance of containment integrity and required instrumentation function will be developed. (Open item 01 4)

Additionally, the 225 kVA 480 Vac DGs discussed in the safety functions support section will provide power directly to the hydrogen igniter supply transformers.

The onsite 3 MW DGs are available to provide power to Containment air return fans or Lower Compartment Coolers (LCCs) for containment temperature control. Cooling water would be provided to the LCCs by the onsite low pressure FLEX pump feeding the ERCW header. As the 3 MW DGs are not required to support the coping strategies, but rather long-term cooling strategies, additional details are not included in this submittal.

Details:

Provide a brief description Procedures and guidance to support deployment and implementation, of Procedures / Strategies / including interfaces to EOPs, special event procedures, abnormal event Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available.

Identify Modifications Power capability will be installed to the hydrogen igniter supply transformers.

Key Containment List instrumentationcredited or recoveredfor this coping evaluation.

Parameters

1. Containment Pressure*

2. Containment Temperature**

• For this instrumentation, the normal power source and the long-term power source are the 125 Vdc Vital Battery.

• • This instrumentation is only available until flood water enters the TSC E-42

Maintain Containment inverter or station battery rooms. (Open Item 01 10)

Storage / Protection of Equipment:

Describe storage / protection plan or schedule to determine storage requirements Seismic The 225 kVA 480 Vac DGs will be pre-staged on the roof of the Auxiliary Building. A protection structure will be built around the DGs, which will be designed to the same Seismic Category I requirements as the Auxiliary Building. Seismic input for the design corresponds to the appropriate seismic accelerations at the roof of the Auxiliary Building. This design provides a minimum HCLPF of the protective structure of 2xSSE.

Flooding The 225 kVA 480 Vac DGs will be pre-staged on the roof of the Auxiliary Building, which is sited in a suitable location that is above the PMF and as such is not susceptible to flooding from any source.

Severe Storms with High The 225 kVA 480 Vac DGs will be pre-staged on the roof of the Auxiliary Winds Building. A protection structure will be built around the DGs, which is sited in a suitable location that is protected from NRC region 1 tornado, missiles, and velocities as defined in Nuclear Regulatory Commission (NRC)

Regulatory Guide 1.76 Revision 1.

Snow, Ice, and Extreme Cold The 225 kVA 480 Vac DGs will be pre-staged on the roof of the Auxiliary Building. A protection structure will be built around the DGs, and will be evaluated for snow, ice and extreme cold temperature effects and heating will be provided as required to assure no adverse effects on the FLEX equipment.

High Temperatures The 225 kVA 480 Vac DGs will be pre-staged on the roof of the Auxiliary Building. A protection structure will be built around the DGs, and will be evaluated for high temperature effects and ventilation will be provided as required to assure no adverse effects on the FLEX equipment.

Deployment Conceptual Modification (Attachment 3 contains Conceptual Sketches)

Strategy Modifications Protection of connections Identify Strategy including how Identify Modifications Identify how the connection is the equipment will be deployed to E-43

Maintain Containment the point of use. protected The hydrogen igniters will be Diverse transfer switches will be The protection structure for the repowered by the 225 kVa 480 Vac installed which directly supply the 225 kVa 480 Vac DGs and the DGs that will be pre-staged on the hydrogen igniter transformers. diverse transfer switches will be roof of the Auxiliary Building. designed and installed such that Cabling will be routed from the each is protected from the five generators to one of the diverse external hazards, as described in transfer switches that will be this section.

installed.

Notes: None E-44

Maintain Containment PWR Portable Equipment Phase 3:

Provide a generaldescription of the coping strategies using Phase 3 equipment including modifications that areproposed to maintain containment. Identify methods (containmentspray/hydrogen igniters) and strategy(ies) utilized to achieve this coping time.

Watts Bar will perform a containment evaluation based on the boundary conditions described in Section 2 of NEI 12-06. Based on the results of this evaluation, required actions to ensure maintenance of containment integrity and required instrumentation function will be developed. (Open item 01 4)

The hydrogen igniters would continue to be repowered by the 225 kVa 480 Vac or 3 MW DGs. A backup or alternate set of Phase 2 equipment will be provided by the RRC as needed.

Details:

Provide a brief description Procedures and guidance to support deployment and implementation, of Procedures / Strategies / including interfaces to EOPs, special event procedures, abnormal event Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available. Finally, Watts Bar will include in procedures notification of the RRC to arrange for delivery and deployment of offsite equipment and sufficient supplies of commodities.

Identify Modifications The same modification as Phase 2 applies for Phase 3.

Key Containment List instrumentationcredited or recoveredfor this coping evaluation.

Parameters

1. Containment Pressure*

2. Containment Temperature**

• For this instrumentation, the normal power source and the long-term power source are the 125 Vdc Vital Battery.

• • This instrumentation is only available until flood water enters the TSC inverter or station battery rooms. (Open Item 01 10)

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

E-45

Maintain Containment Deployment Conceptual Modification (Attachment 3 contains Conceptual Sketches)

Strategy Modifications Protection of connections Identify Strategy including how Identify Modifications Identify how the connection is the equipment will be deployed to protected the point of use.

The same modification, as Phase 2 The same modification, as Phase 2 All FLEX equipment and applies for Phase 3. applies for Phase 3. connection points will be designed to meet or exceed Watts Bar design basis safe shutdown earthquake (SSE) protection requirements.

The same modification, as Phase 2 applies for Phase 3.

Notes: None E-46

Maintain Spent Fuel Pool Cooling Determine Baseline coping capability with installed coping 4 modifications not including FLEX modifications, utilizing methods described in Table 3-2 of NEI 12-06:

Makeup with Portable Injection Source PWR Installed Equipment Phase 1:

Provide a general description of the coping strategies using installed equipment including modifications that areproposedto maintain spentfuel pool cooling. Identify methods (makeup via portable injection source)andstrategy(ies) utilized to achieve this coping time.

Reference 11 summarizes that there will be no volume lost from the SFP due to sloshing. Access to the SFP area as part of Phase 2 response could be challenged due to environmental conditions near the pool.

Therefore, the required action is to establish ventilation in this area and establish any equipment local to the SFP required to accomplish coping strategies (such as the primary SFP cooling strategy discussed below).

If the air environment in the SFP area requires the building to be ventilated, doors will be opened to establish air movement and venting the SFP building. For accessibility, establishing the SFP vent and any other actions required inside the fuel handling building should be completed before boil off occurs.

Operating, pre-fuel transfer or post-fuel transfer Considering no reduction in SFP water inventory starting from nominal pool level, this results in a time when boil off decreases the water level to 10 feet above the SFP racks of approximately 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br /> for an SSE seismic event with an initial bulk water temperature in the pool of 100'F. This value was calculated using the normal operating decay heat load.

Fuel in Transfer or Full Core Offload For the maximum credible heat load and an initial water temperature in the pool of 140'F, the time when boil off decreases the water level to 10 feet above the SFP racks is approximately 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />, as summarized in Reference 11.

In order to keep the pool at a constant level of coolant (thus covering the top of the spent fuel), the low pressure FLEX pump will pressurize the ERCW headers to provide makeup to prevent a decrease in the level of the SFP.

4 Coping modifications consist of modifications installed to increase initial coping time, i.e., generators to preserve vital instruments or increase operating time on battery powered equipment.

E-47

Details:

Provide a brief description Procedures and guidance to support implementation of this strategy, of Procedures / Strategies/ including interfaces to EOPs, special event procedures, abnormal event Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available.

Identify Modifications N/A Key SFP Parameter The implementation of this parameter will align with the requirements of by NRC Order EA 12-051.

This instrument will have initial local battery power, with the capability to be powered from the FLEX 480 Vac generators.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

Notes:

E-48

Maintain Spent Fuel Pool Cooling PWR Portable Equipment Phase 2:

Provide a generaldescription of the coping strategies using on-site portable equipment including modifications that areproposedto maintainspentfuel pool cooling. Identify methods (makeup via portable injection source)andstrategy(ies) utilized to achieve this coping time.

The transition to Phase 2 strategies will be as the inventory in the SFP slowly declines due to boiling. SFP cooling through makeup and spray will be provided by using a FLEX pump to inject coolant directly into the pool, into existing SFP cooling piping, or spray the coolant into the pool using portable FLEX spray nozzles.

Operating, pre-fuel transfer or post-fuel transfer Considering no reduction in SFP water inventory starting from nominal pool level, this results in a time when boil off decreases the water level to 10 feet above the SFP racks of approximately 37 hours4.282407e-4 days <br />0.0103 hours <br />6.117725e-5 weeks <br />1.40785e-5 months <br /> for an SSE seismic event with an initial bulk water temperature in the pool of 100°F. This value was calculated using the normal operating decay heat load.

Fuel in Transfer or Full Core Offload For the maximum credible heat load and an initial water temperature in the pool of 140 0 F, the time when boil off decreases the water level to 10 feet above the SFP racks is approximately 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />, as summarized in Reference 11.

To provide an unlimited supply of water for SFP makeup during Phase 2, a low pressure FLEX pump will be used to pressurize the ERCW headers which can then be used for makeup to the SFP using hoses.

The primary SFP makeup flow method is from the ERCW header spool piece located on the refueling floor, Elevation 757', through hoses directly to the open SFP. The secondary SFP makeup flow method is from the ERCW header connections on Elevation 737' through a hose to a new connection added to the SFP makeup line from the Demineralized Water System (DWS). This alignment provides makeup control when the refueling floor is not accessible. Both connections can be used during both flood and non-flood conditions.

Watts Bar will provide portable monitor (fire-fighting) flow nozzles based on a flow of 500 gpm, which equals the FLEX requirement to provide 250 gpm of spray flow per unit to the spent fuel pool.

For long term cooling of the SFP, Watts Bar intends to repower one train of normal pool cooling equipment at each unit. This will include the use of the low pressure FLEX pump on site to provide flow to the CCS heat exchanger and the onsite 3MW generator to repower both the CCS and SFP cooling pumps. As the 3 MW DGs are not required to support the coping strategies, but rather long-term cooling strategies, additional details are not included in this submittal.

Details:

Provide a brief description Procedures and guidance to support deployment and implementation, of Procedures / Strategies / including interfaces to EOPs, special event procedures, abnormal event E-49

Maintain Spent Fuel Pool Cooling T

Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available.

Identify Modifications List modifications

1. All modifications described for other functions to allow suction to be taken from the CST, RWST, or other surviving tanks will apply to this function.

2. An adapter and Storz connection will be installed at two ERCW supply valves on the SFP elevation to supply direct makeup and spray flow to the pool.

3. The secondary connection will require a new tee, with an upstream isolation valve, a branch line and quick connect capability, to be installed on the DWS piping leading to the SFP.

4. Modifications required to pressurize the ERCW headers are described under Phase 2 Maintain Core Cooling and Heat Removal.

Key SFP Parameter The implementation of this parameter will align with the requirements of by NRC Order EA 12-051.

This instrument will have initial local battery power, with the capability to be powered from the FLEX 480 Vac generators.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

Storage / Protection of Equipment:

Describe storage / protection plan or schedule to determine storage requirements Seismic Portable equipment required to implement this FLEX strategy will be maintained in the FESB, which will be designed for seismic loading in excess of the minimum requirements of American Society of Civil Engineers (ASCE) 7-10. The design of the FESB provides a minimum HCLPF of 2x SSE.

E-50

Maintain Spent Fuel Pool Cooling Flooding Portable equipment required to implement this FLEX strategy will be maintained in the FESB, which is designed to meet or exceed the licensing basis high wind hazard for Watts Bar.

Severe Storms with High Portable equipment required to implement this FLEX strategy will be Winds maintained in the FESB, which is sited in a suitable location that is protected from NRC region 1 tornado, missiles, and velocities as defined in NRC Regulatory Guide 1.76 coupled with 360 mph wind speeds (Reference 5 Paragraph 2.3.1).

Snow, Ice, and Extreme Cold The FESB will be evaluated for snow, ice and extreme cold temperature effects and heating will be provided as required to assure no adverse effects on the FLEX equipment. The FESB will have a standalone HVAC system.

High Temperatures The FESB will be evaluated for high temperature effects and ventilation will be provided as required to assure no adverse effects on the FLEX equipment. The FESB will have a standalone HVAC system.

Deployment Conceptual Design (Attachment 3 contains Conceptual Sketches)

Strategy Modifications Protection of connections Identify Strategy including how Identify Modifications Identify how the connection is the equipment will be deployed to protected the point of use.

The primary method is flow from Primary Method Modification All FLEX equipment and the ERCW headers at two connection points will be designed locations using adapters and hose An adapter with hose connection to meet or exceed Watts Bar connections at the 757' level. This will be installed at the ERCW design basis SSE protection strategy can be implemented in supply valve to the CCS surge requirements.

flood and non-flood conditions. tank flood mode spool piece.

The primary connection is in the The proposed hose routing for the ERCW Modifications Auxiliary Building, which is primary method and the associated seismically qualified and missile equipment can be found in The same modifications required protected. The primary , Figure A3-23 to pressurize ERCW headers are connection is above the PMF.

through A3-25. The system described under Phase 2 Maintain connection point can be found in Core Cooling and Heat Removal. Protection of CST, RWST, and , Figure A3-2 1. other surviving tanks is described under Phase 2 Maintain Core E-51

Maintain Spent Fuel Pool Cooling T -~

Note that SFP spray would be Cooling and Heat Removal.

routed in an identical manner; however, the end of the hose would have the spray nozzle installed. CST. RWST and other surviving tanks Modifications An alternate supply to the SFP can be provided using transfer pumps All modifications described for from the RWST, CST or other other functions to allow suction to surviving tanks by routing hoses be taken from the CST, RWST, or to the SFP elevation. This strategy other surviving tanks will apply to is for non-flood conditions only. this function.

ERCW connections can be found in Attachment 3, Figures A3-26 and A3-27.

+ -I-The secondary SFP connection "ýnnAn 1---nn f;~n All FLEX equipment and will be to the DWS makeup line, Modification connection points will be designed on Elevation 737' of the Auxiliary to meet or exceed Watts Bar Building. This strategy can be

• A tee will be added to the design basis SSE protection implemented in flood and non- DWS makeup line to the SFP requirements.

flood conditions. " An isolation valye will be added to the main line The connection point is on the FLEX hose will be routed from upstream of the connection. exterior of the Auxiliary Building, this location, across the floor on " An isolation valve will be which is seismically qualified and Elevation 737', to the ERCW added to the new branch. missile protected. Hose routing to cleanout port connections.

• Storz cap/adapter will be the secondary connection will be added to the new branch. performed before flood conditions An alternate supply involves make the area inaccessible and a routing fire hose from the RWST, hose throttle valve will be CST, or other surviving tanks to CST, RWST, ERCW or other provided above the PMF.

the SFP floor. This strategy is for surviving tanks Modifications non-flood conditions. Connections to the ERCW, CST, The modification for these sources RWST and other surviving tanks The proposed hose routing for the would be the same as for the have been described in Phase 2 secondary connection and the primary method for this function. Reactor Core Cooling and Heat associated equipment can be found In addition, the modification to Removal.

in Attachment 3, Figure A3-23 add a hose connection to the through A3- 25. The system ERCW cleanout ports described in connection point can be found in the Reactor Core Cooling and , Figure A3-22. Heat Removal section also applies to this case due to the location of E-52

Maintain Spent Fuel Pool Cooling the connection point.

ERCW connections can be found in Attachment 3, Figures A3-26 and A3-27.

Notes:

1. System modifications are described in the "Modifications" section above and are illustrated in Attachment 3.

2. Figures A3-23 through A3-25 in Attachment 3 provide the hose routing for the SFP makeup strategies.

E-53

Maintain Spent Fuel Pool Cooling PWR Portable Equipment Phase 3:

Provide a general description of the coping strategies using Phase 3 equipment including modifications that areproposed to maintain spentfuel pool cooling. Identify methods (makeup via portable injection source)andstrategy(ies) utilized to achieve this coping time.

Details:

The strategies described for Phase 2 can continue as long as there is sufficient inventory available to feed the strategies. As mentioned for the Reactor Core Cooling and Heat Removal function, a mobile water purification unit will be received from the RRC to provide continued purified water to support this function.

Additionally, as mentioned for the Maintain RCS Inventory Control function, a mobile boration unit will be received from the RRC to provide continued borated coolant to support this function, if required.

Watts Bar will determine where Phase 3 equipment will be staged (Open item 01 5).

Also, a backup or alternate set of Phase 2 equipment will be provided by the RRC as needed.

Provide a brief description Procedures and guidance to support deployment and implementation, of Procedures / Strategies / including interfaces to EOPs, special event procedures, abnormal event Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available. Finally, Watts Bar will include in procedures notification of the RRC to arrange for delivery and deployment of offsite equipment and sufficient supplies of commodities.

Identify Modifications N/A Key SFP Parameter The implementation of this parameter will align with the requirements of by NRC Order EA 12-051.

This instrument will have initial local battery power, with the capability to be powered from the FLEX 225 kVa 480 Vac generators.

E-54

Maintain Spent Fuel Pool Cooling Deployment Conceptual Design (Attachment 3 contains Conceptual Sketches)

Strategy Modifications Protection of connections Identify Strategy including how Identify Modifications Identify how the connection is the equipment will be deployed to protected the point of use.

The description for the mobile The description for the mobile The description for the mobile boration unit and water boration unit and water boration unit and water purification system will be the purification system will be the purification system will be the same as was mentioned for the same as was mentioned for the same as was mentioned for the other functions. other functions. other functions.

Notes: None E-55

Safety Functions Support Determine Baseline coping capability with installed coping5 modifications not including FLEX modifications.

PWR Installed Equipment Phase 1 Provide a general description of the coping strategies using installed equipment including station modifications that are proposed to maintain and/or support safety functions. Identify methods and strategy(ies) utilized to achieve coping times.

Watts Bar will rely on existing installed vital batteries to power key instrumentation and emergency lighting. To extend run time before recharging is possible; a load-shedding procedure will be implemented with the first phase of load shed complete by 45 minutes and the extended load shed complete by 90 minutes. A battery coping calculation determined that the battery coping time is 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, as summarized in Reference 1 .

Preliminary analysis using conservative heat loads in the Auxiliary and Control Buildings has shown that installed equipment credited for mitigation response will remain available. In addition, accessibility of these areas for required actions is acceptable.

Details:

Provide a brief description Confirm that procedure/guidanceexists or will be developed to support of Procedures / Strategies / implementation.

Guidelines Procedures and guidance to support deployment and implementation, including interfaces to EOPs, special event procedures, abnormal event procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available.

Identify Modifications List modifications and describe how they sup~port coping time.

N/A 5 Coping modifications consist of modifications installed to increase initial coping time, i.e., generators to preserve vital instruments or increase operating time on battery powered equipment.

E-56

Y Key Parameters List instrumentationcreditedfor this coping evaluationphase.

DC Bus Voltage For all instruments listed above the normal power source and the long-term power source are the 125 Vdc Vital Battery.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

Notes:

Safety Functions Support PWR Portable Equipment Phase 2 Provide a generaldescription of the coping strategies using on-site portable equipment includingstation modifications that areproposedto maintain and/orsupport safetyfunctions. Identify methods and strategy(ies) utilized to achieve coping times.

The primary electrical need during Phase 2 is DC power for critical instrumentation. This will be accomplished by energizing the support power system and energizing battery chargers on both A and B trains in both Units I and 2.

The on-site 225 kVA 480 Vac FLEX DGs are pre-staged to provide power to the 125 Vdc vital battery and 120 Vac vital inverter power systems. These generators will be pre-staged on the Auxiliary Building roof and will be protected from the external hazards with an adequate supply of fuel for 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of operation. The 225 kVA 480 Vac FLEX DGs will be connected to the battery chargers to power the DC and AC Vital Power System.

Additionally, the onsite 3 MW DGs are pre-staged to provide power to the existing 6.9 kV distribution system. The 3 MW DGs may also serve as an alternative power source for the loads supplied by the on-site 225 kVA 480 Vac FLEX DGs. Further analysis will be performed to determine the required timeline for this alternate strategy (Open Item 01 14). These generators will be staged in the FESB and protected from the external hazards discussed in this document. As the 3 MW DGs are not required to support the coping strategies, but rather long-term cooling strategies, additional details are not included in this submittal.

Details:

E-57

Safety Functions Support PWR Portable Equipment Phase 2 Provide a brief description Confirm that procedure/guidanceexists or will be developed to support of Procedures / Strategies / implementation with a descriptionof the procedure/ strategy/ guideline.

Guidelines Procedures and guidance to support deployment and implementation, including interfaces to EOPs, special event procedures, abnormal event procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available.

Identify Modifications For the 225 kVa 480 Vac DGs, two fused distribution panels will be used to provide power to the supplied loads. Each fuse panel provides connections to two vital battery chargers and one train of hydrogen igniters for each unit.

Each fuse distribution panel will have a connection to 480 Vac distribution to close Cold Leg Accumulator Isolation valves during cooldown.

Fuel for the 225 kVa 480 Vac DGs will be provided by the installed DG 7-day tanks. Fuel lines will be installed between the 7-day fuel tanks mounted under the Diesel Generator building and Auxiliary Building roof to provide fuel to the 225 kVa 480 Vac DGs with a fuel transfer pump.

To connect the existing 6.9 kV system to the 3 MW DGs during FLEX operation, the connection to the existing safety-related Diesel Generator circuit is opened and the circuits to the 3 MW generators are closed by operating the existing interlocked transfer switches 1A-A, 1B-B, 2A-A, or 2B-B. This will be done under administrative controls, ensuring that a no-load condition exists on the load side of the transfer switches.

The permanently installed electrical connection points for the 3MW DGs are from the DGs' integral output connection panel through conduits within the FESB to underground conduits located on the outside of the FESB south wall. One 3MW DG will be assigned to Train A on both units and the second 3MW DG will be assigned to Train B of both units.

The conduits will meet seismic Class I requirements for safety related and quality-related structures. Actual mechanical and electrical connections to the presently installed safety related DG equipment shall meet safety related requirements at the interfaces.

Refueling of the 3MW DGs will be accomplished using a separate diesel fuel transfer pump dedicated for the purpose of transferring fuel from the 7-day tanks to the 3MW DGs' fuel oil day tanks. As the 3 MW DGs are not required to support the coping strategies, but rather long-term cooling strategies, additional details are not included in this submittal.

E-58

Safety Functions Support PWR Portable Equipment Phase 2 Key Parameters List instrumentationcredited or recoveredfor this coping evaluation.

DC Bus Voltage For the instrument listed above the normal power source and the long-term power source are the 125 Vdc Vital Battery.

Watts Bar will develop procedures to read this instrumentation locally, where applicable, using a portable instrument as required by Section 5.3.3 of NEI 12-06.

Storage / Protection of Equipment :

Describe storage / protection plan or schedule to determine storage requirements Seismic Equipment for this function will either be stored or pre-staged in the FESB, in the Auxiliary Building, or on the Auxiliary Building roof. The protection of FLEX equipment for this hazard is addressed for each of these locations in the Reactor Core Cooling and Heat Removal and Maintain RCS Inventory Control sections.

Flooding Equipment for this function will either be stored or pre-staged in the FESB, in the Auxiliary Building, or on the Auxiliary Building roof. The Note: if stored below current flood level, then protection of FLEX equipment for this hazard is addressed for each of ensure procedures exist to move equipment these locations in the Reactor Core Cooling and Heat Removal and prior to exceeding flood level. Maintain RCS Inventory Control sections.

Severe Storms with High Winds Equipment for this function will either be stored or pre-staged in the FESB, in the Auxiliary Building, or on the Auxiliary Building roof. The protection of FLEX equipment for this hazard is addressed for each of these locations in the Reactor Core Cooling and Heat Removal and Maintain RCS Inventory Control sections.

Snow, Ice, and Extreme Cold Equipment for this function will either be stored or pre-staged in the FESB, in the Auxiliary Building, or on the Auxiliary Building roof. The protection of FLEX equipment for this hazard is addressed for each of these locations in the Reactor Core Cooling and Heat Removal and E-59

Safety Functions Support PWR Portable Equipment Phase 2 Maintain RCS Inventory Control sections.

High Temperatures Equipment for this function will either be stored or pre-staged in the FESB, in the Auxiliary Building, or on the Auxiliary Building roof. The protection of FLEX equipment for this hazard is addressed for each of these locations in the Reactor Core Cooling and Heat Removal and Maintain RCS Inventory Control sections.

Deployment Conceptual Design (Attachment 3 contains Conceptual Sketches)

Strategy Modifications Protection of connections Identify Strategy including how Identify Modifications Identify how the connection is the equipment will be deployed to protected the point of use.

The strategy for this function is The modifications for this function The protection structure for the described above in the Identify are described in the Identify 225 kVa 480 Vac DGs will be Modifications section. Modifications section. designed and installed such that each is protected from the five external hazards, as described in this section. The fuse distribution panels for the 225 kVa 480 Vac DGs will be located inside the Auxiliary Building which will provide protection from the external hazards, as described in this section.

Notes: None.

E-60

Safety Functions Support PWR Portable Equipment Phase 3 Provide a generaldescription of the coping strategies using Phase 3 equipment including modifications that areproposed to maintain and/or support safetyfunctions. Identify methods and strategy(ies) utilized to achieve coping times.

A backup or alternate set of Phase 2 equipment will be provided by the RRC, as needed. Watts Bar will determine where Phase 3 equipment will be staged (Open item 01 5).

Details:

Provide a brief description Procedures and guidance to support deployment and implementation, of Procedures / Strategies / including interfaces to EOPs, special event procedures, abnormal event Guidelines procedures, and system operating procedures, will be developed in accordance with NEI 12-06, Rev. 0, Section 11.4. Further, the PWROG has developed generic guidance, and Watts Bar's strategy aligns with the generic guidance and will consider the NSSS specific guidance once available. Finally, Watts Bar will include notification of the RRC in plant procedures to arrange for delivery and deployment of off-site equipment and sufficient supplies of commodities.

Identify Modifications N/A Key Parameters No additional instrumentation is required to support the Phase 3 safety function support.

Deployment Conceptual Design (Attachment 3 contains Conceptual Sketches)

Strategy Modifications Protection of connections Identify Strategy including how Identify Modifications Identify how the connection is the equipment will be deployed to protected the point of use.

A backup or alternate set of Each of the Phase 3 strategies will There are no connection points for Phase 2 equipment will be utilize common connections as this strategy. All equipment will provided by the RRC, as needed. described for the Phase 2 be provided by offsite resources.

connections to prevent any compatibility issues with the offsite equipment.

E-61

Safety Functions Support PWR Portable Equipment Phase 3 Notes: None E-62

PWR Portable Equipment Phase 2 Use and (potential/flexibility)diverse uses Performance Criteria' Maintenance List portable Core Containment SFP Instrumentation Accessibility Maintenance / PM equipment requirements Three X 346 gpm Will follow EPRI Intermediate 942 ft total dynamic head template requirements Pressure FLEX (TDH)

Pumps (Core Diesel Driven Cooling Makeup)

Four High X 10 gpm Will follow EPRI Pressure FLEX 3561 ft TDH template requirements Pumps (RCS) 480 Vac Two Water X X 500 gpm Will follow EPRI Transfer Pumps 247 ft TDH template requirements Diesel Driven Two Low Voltage X x X X X 480 Vac Will follow EPRI Diesel 225 kVA template requirements Generators Tow Vehicle X X X Capable of on-site Will follow EPRI transport of 14,000 Gross template requirements Vehicle Weight (GVW)

Performance criteria of FLEX equipment is conservative and was determined during conceptual design as a basis for the selection of required FLEX equipment.

The criteria will be re-analyzed during the detailed design phase (01 7).

E-63

PWR Portable Equipment Phase 2 Use and (potential/flexibility)diverse uses PerformanceCriteria' Maintenance List portable Core Containment SFP Instrumentation Accessibility Maintenance / PM equipment requirements trailer Fuel X X X X 500 gallons Will follow EPRI Transportation Minimum template requirements Equipment Three Low X X X 5000 gpm Will follow EPRI Pressure FLEX 350 ft TDH template requirements Pumps Diesel Driven (Pressurizes ERCW Headers)

Three Floating X X 5000 gpm Will follow EPRI Booster Pumps 50 ft lift template requirements (Supplies Low Diesel Driven Pressure FLEX Pump)

E-64

PWR Portable Equipment Phase 2 Use and (potential/flexibility) diverse uses Performance Criteria Maintenance List portable Core Containment SFP Instrumentation Accessibility Maintenance / PM equipment requirements Three X 200 gpm Will follow EPRI Submersible 90 TDH template requirements Pumps (Supplies 480Vac Intermediate Pressure FLEX pump)

Three X 30 gpm Will follow EPRI Submersible 90 TDH template requirements Pumps (Supplies Electrical High Pressure FLEX pump)

Two SFP Spray X 250 gpm Will follow EPRI Nozzles template requirements Two Diesel Fuel X X X 200 gpm Will follow EPRI Transfer Pumps Diesel Driven template requirements Two Medium X X X X X *6900 V Will follow EPRI Voltage Diesel 3 MW template requirements Generator E-65

PWR Portable Equipment Phase 2 Use and (potential/flexibility)diverse uses PerformanceCriteria' Maintenance List portable Core Containment SFP Instrumentation Accessibility Maintenance / PM equipment requirements Crane or other X X X 5,000 lb. lift capacity Will follow EPRI lift equipment Minimum template requirements (for staging pumps on Auxiliary Building roof)

Debris Clearing X Capable of clearing trees, Will follow EPRI Equipment light poles, construction template requirements materials and miscellaneous debris

• This can be achieved with a 4160 V DG and transformer to provide a 6900 V source E-66

PWR Portable Equipment Phase 3 Use and (potential/flexibility)diverse uses Performance Criteria Notes List portable Core Containment SFP Instrumentation Accessibility equipment Intermediate X X 346 gpm Will follow EPRI template Pressure 942 ft TDH requirements FLEX Pumps Diesel Driven (Core Cooling

..Backup) Pump High Pressure X 10 gpm Will follow EPRI template FLEX Pump 3561 ft TDH requirements Backup 480Vac Water X X 500 gpm Will follow EPRI template Transfer Pump 247 TDH requirements Backup Diesel Driven Low Voltage X X X X X 480 Vac Will follow EPRI template Diesel 225 kVA requirements Generators Backup Medium X X X X X *6900V Will follow EPRI template Voltage Diesel 3MW requirements Generator Backup I Performance criteria of FLEX equipment is conservative and was determined during conceptual design as a basis for the selection of required FLEX equipment. The criteria will be re-analyzed during the detailed design phase (01 7).

• This can be achieved with a 4160 V DG and transformer to provide a 6900 V source E-67

PWR Portable Equipment Phase 3 Use and (potential/flexibility)diverse uses Performance Criteria Notes List portable Core Containment SFP Instrumentation Accessibility equipment Low Pressure X X X 5000 gpm Will follow EPRI template FLEX Pump 350 ft TDH requirements Backup Diesel Driven Submersible X 200 gpm Will follow EPRI template Pump Backup 90 TDH requirements (Supplies 480Vac Intermediate Pressure FLEX pump)

Submersible X 30 gpm Will follow EPRI template Pump Backup 90 TDH requirements (Supplies High Electrical Pressure FLEX pump)

Backup Diesel X X X 200 gpm Will follow EPRI template Fuel Transfer Diesel Driven requirements Pumps Fuel X X X X 500 gallons Will follow EPRI template Transportation Minimum requirements Equipment Backup E-68

PWR Portable Equipment Phase 3 Use and (potential/flexibility)diverse uses Performance Criteria Notes List portable Core Containment SFP Instrumentation Accessibility equipment Mobile X X Open Item 01 9 This item to be developed Boration Unit in detailed design.

Mobile Water X X Open Item 01 9 This item to be developed Purification in detailed design.

Unit E-69

Phase 3 Response Equipment/Commodities Item Notes Radiation Protection Equipment

• Survey instruments

• Dosimetry

• Off-site monitoring/sampling

" Radiological counting equipment

• Radiation protection supplies

• Equipment decontamination supplies

• Respiratory protection

" Portable Meteorological (MET) Towers Commodities

" Food o Meals ready to eat (MRE) o Microwavable Meals

• Potable water Fuel Requirements

• Diesel Fuel Heavy Equipment

" Transportation equipment o 4 wheel drive tow vehicle

• Debris clearing equipment Communications Equipment 0 Satellite Phones e Portable Radios E-70

Portable Interior Lighting

" Flashlights

" Headlamps

" Batteries Portable Exterior Lighting

• Light units with diesel generator E-71

References

1. NRC EA-12-049, "Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," March 12, 2012. [ADAMS Accession Number ML12054A735]

2. NEI 12-06, Revision 0, "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide," August 2012.

3. NRC JLD-ISG-2012-01, Revision 0, "Compliance with Order EA-12-049, 'Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events,"' August 2012.

4. Watts Bar Nuclear Plant Updated Final Safety Analysis Report (UFSAR), Amendment 9, November 21, 2011.

5. Watts Bar Nuclear Plant Unit 2 Final Safety Analysis Report (FSAR), Amendment 109.

6. Not Used.

7. Not Used.

8. WCAP-17601-P, Revision 1, "Reactor Coolant System Response to the Extended Loss of AC Power Event for Westinghouse, Combustion Engineering, and Babcock & Wilcox NSSS Designs," PWROG Project PA-ASC-0916, January 2013.

9. LAR WBN-UFSAR-12-01, "Application to Revise Watts Bar Nuclear Plant Unit 1 Updated Final Safety Analysis Report Regarding Changes to Hydrologic Analysis, TAC No. ME8200, "July 19, 2012. (Accession No. ML12236A167)

10. TVA Drawings

a. 46W501-1, Revision J, Architectural Plan El 676.0 & 692.0.

b. 46W501-2, Revision J, Architectural Plan El 708.0 & 713.0.

c. 46W501-3, Revision K, Architectural Plan El 729.0 & 737.0.

d. 46W501-4, Revision K, Architectural Plan El 755.0 & 757.0.

e. 46W501-5, Revision F, Architectural Plan El 782.0 & 786.0.

f. 47W200-1, Revision 12, Equipment Plans - Roof

11. TR-FSE-13-1, Revision 2, "Watts Bar Integrated Plan," February 2013.

12. Task Interface Agreement (TIA) 2004-04, "Acceptability of Proceduralized Departures from Technical Specifications (TSs) Requirements at the Surry Power Station," (TAC Nos.

MC4331 and MC4332)," dated September 12, 2006. (Accession No. M1L060590273)

13. OG-12-482, Revision 0, "Transmittal of PA-PSC-0965 Core Team PWROG Core Cooling Management Interim Position Paper," November, 2012.

14. FLEX Implementation HVAC Analysis Impact Study, Project No. 12938-012.

15. AOI-40, Rev. 16, "Station Blackout," March 1, 2012.

16. OG-12-515, "Transmittal of Final Generic PWROG FLEX Support Guidelines and Interfaces (Controlling Procedure Interface and Recommended Instruments) from PA-PSC-0965,"

Revision 0, December 2012.

17. 1-ECA-0.0, Rev. 0, Loss of Shutdown Power.

E-72

Open Items 011. The current CST is a non-seismic tank that is not missile protected. The site is currently pursuing two options; the qualification and hardening of the existing CST, or the construction of a new seismically qualified and missile protected CST. One of these options must be completed before the volume of the CST can be credited.

01 2. Liquefaction of haul routes for FLEX will be analyzed.

01 3. No detailed analysis has been provided regarding initial FLEX fuel supplies to determine a need time for access to 7 day tank supplies or resupply of the 7 day tanks. It is assumed that each FLEX component is stored with a minimum supply of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of fuel at constant operation. This assumption will need to be assessed once all FLEX equipment has been purchased and equipment specifications are known.

01 4. No need time has been identified for action to protect containment. This includes actions to mitigate pressurization of containment due to steaming when RCS vent paths have been established or actions to mitigate temperature effects associated with equipment survivability. An evaluation will be provided to prove indefinite containment coping.

01 5. The Phase 3 equipment staging area has not been determined.

01 6. A strategy for clearing and removing debris will be determined.

01 7. A thorough analysis of the makeup flow rate requirements and other equipment characteristics will be finalized during the detailed design phase of FLEX.

01 8. The need time for SFP cooling actions (deployment of hose, venting, and alignment of makeup) was determined using worst case heat loads. This item will continue to be assessed and later action times may be acceptable. Note that the timing for this step during an outage is different, but resources will be available to complete the required actions.

01 9. Functional requirements for each of the Phase 3 strategies, equipment and components will be completed at a later time and will be provided in the six month updates to the February 28, 2013 submittal.

0110. Containment temperature instrumentation is only available until flood waters enter the TSC inverter or station battery rooms. Requirements for NSSS-specific FSGs for containment temperature, as noted in APPENDIX F of Reference 11, are pending further evaluation. A method to monitor containment temperature, post-flood, will be developed.

0111. The HVAC analysis (Reference 14) is preliminary, and has not been finalized.

0112. Verify ability to deploy FLEX equipment to provide core cooling in Modes 5 and 6 with SGs unavailable.

0113. An evaluation of the impact of FLEX response actions on design basis flood mode preparations will be performed. This evaluation will include the potential for extended preparation time for FLEX. Changes which affect the Integrated Plan will be included in the six month update.

01 14. Further analysis will be performed to determine the required timeline for implementing the 3 MW DGs as an alternate power source for the loads supplied by E-73

the 225 kVA 480 Vac DGs.

0115. The CETs are only available until water enters the auxiliary instrument room. A method to monitor CET, post flood, will be evaluated and developed, if required.

0116. Strategies to address extreme cold conditions on the RWST and/or BATs, including potential need to reenergize heaters have not been finalized.

0117. Establish a contract with the SAFER team in accordance with the requirements of Section 12 of Reference 2.

0118. Manual SBO load shedding time in References 4 and 5, Section 8.3.2.1.1, will be revised from 30 minutes to 45 minutes as supported by the 8 hour9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> ELAP battery calculations (Reference 11).

E-74

ACRONYMNS ABMT auxiliary boration makeup tank ac alternating current ACR auxiliary control room ACS alternate coolant system AFW auxiliary feedwater AOI abnormal operating instruction AOP abnormal operating procedure AOV air-operated valve APM available physical margin ARV atmospheric relief valve AUO assistant unit operator BAT boric acid tank BCS backup control station BDB beyond-design-basis BDBEE beyond-design-basis external events CCS component cooling system CFR Code of Federal Regulations CLA cold leg accumulator CLB current licensing basis CST condensate storage tank CVCS chemical and volume control system CWST cask washdown .storage tank DBFL design basis flood level DBE design basis event dc direct current DG diesel generator DGB diesel generator building DWHT demineralized water head tank DWST demineralized water storage tank EDG emergency diesel generator EDMG extreme damage mitigation guideline EFW Emergency Feedwater ELAP extended loss of ac power EOI emergency operating instruction EOP emergency operating procedure EPRI Electric Power Research Institute ERCW essential raw cooling water ERO emergency response organization ESF engineered safety feature FESB FLEX equipment storage building FLEX Flexible and Diverse Coping Mitigation Strategies FMBMS flood mode boration makeup system FSG FLEX support guideline E-75

HCLPF high confidence of low probability failure HPFP high pressure fire protection HVAC heating, ventilation, and air conditioning IER Industry Event Report INPO Institute of Nuclear Power Operations ISG Interim Staff Guidance LCV level control valve LOCA loss of coolant accident LOOP loss of offsite power LUHS loss of normal access to the ultimate heat sink MCC motor control centers MCR main control room MDAFWP motor driven auxiliary feedwater pump MOV motor operated valve MRE meals ready to eat MSL mean sea level NEI Nuclear Energy Institute NPSH net positive suction head.

NRC Nuclear Regulatory Commission NSSS nuclear steam supply system NTTF Near-Term Task Force OBE Operating Basis Earthquake PORV power operated relief valve PMF probable maximum flood PMP probable maximum precipitation PRA probabilistic risk assessment PWR pressurized water reactor PWROG Pressurized Water Reactor Owners Group PWST primary water storage tank QR quality related RCP reactor. coolant pump RCS reactor coolant system RHR residual heat removal RRC Regional Response Center RWST refueling water storage tank RWT raw water tank SAFER Strategic Alliance for FLEX Emergency Response SAMG severe accident management guideline SBO station blackout SFP spent fuel pool SG steam generator SIP safety injection pump SIS safety injection system SPRA seismic probabilistic risk assessment SR safety related S/RVs Safety/Relief Valves E-76

SSC systems, structures and components SSE safe shutdown earthquake, TD turbine-driven TDH total dynamic head TSC technical support center TDAFWP turbine driven auxiliary feedwater pump TOAF top of active fuel TVA Tennessee Valley Authority TWST tritiated water storage tank UFSAR updated final safety analysis report UHS ultimate heat sink E-77

Attachment 1A Sequence of Events Timeline New ELAP Elapsed time Time Time Action Time1 constraint Constraint Constraint item (hours) Action Y/N (hours) Reference Remarks / Applicability 0 Event Starts NA NA Reference 11 Plant @100% power 0 SBO N NA Reference 11 I-ECA-0.0 (Reference 17),

1 0 Initial Load Shed N 0.75 References 4 Completed within 45 minutes and 5, Section (0.75 hours8.680556e-4 days <br />0.0208 hours <br />1.240079e-4 weeks <br />2.85375e-5 months <br />) following the start 8.3.2.1.1 of the event.

(Open Item 01 AOI 40 (Reference 15) 18)

'Elapsed time is defined as the time from the loss of power due to the external event until the action is initiated. These times are conceptual and will be refined as FLEX strategies are verified.

EAI-1

New ELAP Elapsed time Time Time Action Time1 constraint Constraint Constraint item (hours) Action Y/N (hours) Reference Remarks / Applicability 2 0.75 Declare ELAP Y 1.0 Reference II ELAP entry conditions can be verified by control room staff and it is validated by emergency diesel generators (EDGs) not available. This step is time sensitive because entry into ELAP provides guidance to operators to perform ELAP actions. ELAP will be declared within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

3 0.75 Extended Load Shed Y 1.5 Reference 11 Completed within 90 minutes (1.5 hours5.787037e-5 days <br />0.00139 hours <br />8.267196e-6 weeks <br />1.9025e-6 months <br />) following the start of the event. This consists of additional load shedding such that generally, only FLEX required loads remain powered.

EAI-2

New ELAP Elapsed time Time Time Action Time' constraint Constraint Constraint item (hours) Action Y/N (hours) Reference Remarks / Applicability 4 2 Debris Removal (Access) Y 12 Reference 11 Deployment paths will need to be cleared, to the extent necessary, to align the low pressure FLEX pump to the ERCW headers and RCS makeup pump staging.

(Open Item 01 6) 5 3 Perform Damage Assessment Y 6 Reference 11 Provide status of essential plant SSCs to inform FLEX strategies. This assessment will determine what strategies and water sources will be required.

6 6.5 Align RCS Make-up Pump from BAT Y 8 Reference 11 Plant cooldown commences at (Boration) 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />. Time also allows adequate time for boration injection from the BAT. Time based on installation of 4 SHIELD seals and not having to start cooldown until 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

EA 1-3

New ELAP Elapsed time Time Time Action Time1 constraint Constraint Constraint item (hours) Action Y/N (hours) Reference Remarks / Applicability 7 6 Deploy Hoses to SFP Area Y 6.9 Reference 11 Need time based on SFP time to boil off occurs.

8 6 Vent SFP area Y 6.9 Reference 11 Need time based on SFP time to boil off occurs.

9 7 Align 225 kVA 480 Vac Generator Y 8 Reference 11 Earliest need for generator is 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

10 8 Perform plant cooldown Y 12 Reference 11 Based on installation of 4 SHIELD seals, a cooldown start time of 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> and duration of less than 4 hours4.62963e-5 days <br />0.00111 hours <br />6.613757e-6 weeks <br />1.522e-6 months <br />.

RCS make-up must be initiated by 9.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> from the BAT for boration. RCS make-up is initiated at the start of the cooldown at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> to make up for shrinkage.

11 9 Validate Alternate Fuel Supply Y 11 Reference 11 Depletion of FLEX fuel supplies for pumps (8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> +

equipment deployment time).

EA 1-4

New ELAP Elapsed time Time Time Action Time' constraint Constraint Constraint item (hours) Action Y/N (hours) Reference Remarks / Applicability 12 8 Align SG makeup from the ERCW Y 10 Reference 11 CST will be depleted in 10 system piping hours, at which point the standing water in the ERCW headers will be used. The ERCW headers will need to be aligned prior to these both depleting.

13 8.5 Control Room (CR) Lighting N NA Reference 11 CR lighting is available via batteries, ensure portable lighting is available for required activities.

14 10.5 Align charging of the ERCW System Y 14.7 Reference 11 CST will be depleted in 10 Header hours plus 4.7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> of standing water inventory in the ERCW headers. The low pressure FLEX pump will need to be aligned to the ERCW headers to provide charging prior to both of these sources depleting.

EA 1-5

New ELAP Elapsed time Time Time Action Time' constraint Constraint Constraint item (hours) Action Y/N (hours) Reference Remarks / Applicability 15 21.5 Align RCS make-up pump from RWST Y 24.0 Reference 11 Boration from the BAT will (Long term inventory control) be finished by 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Makeup source is then switched to the RWST for flooded conditions for long term inventory control.

16 22 Stage SG Make-up Pump from the Y 24.0 Reference 11 TDAFWP is not anticipated to ERCW System Header fail catastrophically. Back-up should be staged as soon as time and resources permit.

17 24 Establish HVAC / Fan Cooling N 24.0 Reference 11 HVAC study (Reference 14)

Battery/Switchgear Room determined this action not required until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into ELA-P event; at which point it can be monitored periodically if needed.

EA i-6

New ELAP Elapsed time Time Time Action Time' constraint Constraint Constraint item (hours) Action Y/N (hours) Reference Remarks / Applicability 18 24 Main Control Room Ventilation N 24.0 Reference 11 Action completed by opening Main Control Room rear panel (AOI-40). HVAC study (Reference 14) determined this action not required until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into ELAP event; at which point it can be monitored periodically if needed.

19 24 TDAFWP Room Ventilation N 24.0 Reference 11 HVAC study (Reference 14) determined this action not required until 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into ELAP event; at which point it can be monitored periodically if needed. (Reference 14) 20 30 Align Mobile Water Purification System Y 72.0 Reference 11 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> of CST + 62 hours7.175926e-4 days <br />0.0172 hours <br />1.025132e-4 weeks <br />2.3591e-5 months <br /> of ERCW system (further evaluation required to extend).

EA 1-7

New ELAP Elapsed time Time Time Action Time' constraint Constraint Constraint item (hours) Action Y/N (hours) Reference Remarks / Applicability 21 36 Align SFP Make-up via ERCW headers. Y 37.0 Reference 11 Time to boil plus 104 ft3 of water per inch in the pool, from lowest pipe penetration level (749') to 10 ft above the fuel (734') at 70 gpm.

22 38 Align Mobile Boration Unit Y >72.0 Reference 11 RWST will provide source for more than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

23 40 Align Large Generators Y >72.0 Reference 11 Action initiated to deploy generator to support repowering various installed pumps to provide indefinite coping capability.

24 58 Establish Large Fuel Truck Service Y >72.0 Reference 11 Onsite fuel supplies last greater than 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />.

EA 1-8

Attachment lB NSSS Significant Reference Analysis Deviation Table EA 1-9

Attachment 2 Milestone Schedule The following milestone schedule is provided. The dates are planning dates subject to change as design and implementation details are developed. Any changes to the following target dates will be reflected in the subsequent 6 month status reports.

Status Original Target (Will be updated Activity Date every 6 months)

Submit Overall Integrated Implementation Plan 2/28/2013 6 Month Status Updates Update I Aug 2013 Update 2 Feb 2014 Update 3 Aug 2014 Update 4 Feb 2015 Update 5 Aug 2015 Update 6 Feb 2016 FLEX Strategy Evaluation Jun 2013 Perform Staffing Analysis Jun 2014 Modifications Modifications Evaluation Apr 2013 Engineeringand Implementation Unit I N-I Walkdown Apr 2013 Unit 2 Construction Walkdown Apr 2013 Design Engineering Unit I Implementation Outage Apr 2014 Unit 2 Implementation (Startup) Apr 2014 EA2-1

Status Original Target (Will be updated Activity Date every 6 months)

On-Site FLEX Equipment Purchase Jun 2013 Procure Feb 2014

• Off-Site FLEX Equipment Develop Strategies with RRC Dec 2013 Install Off-site Delivery Station (if necessary) Apr 2014 Procedures PWROG issues FSG guidelines Jun 2013 Create Watts Bar FSG Jun 2014 Create MaintenanceProcedures Jun 2014 Training Develop TrainingPlan Jan 2014 Implement Training Jun 2014 Submit Completion Report Aug 2014 EA2-2