CNL-16-182, Fifth Six-Month Status Report in Response to the June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions

Fifth Six-Month Status Report in Response to the June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions

ML16357A577
Person / Time
Site:	Browns Ferry
Issue date:	12/22/2016
From:	James Shea Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CNL-16-182, EA-13-109, TAC MF4540, TAC MF4541, TAC MF4542
Download: ML16357A577 (18)

Text

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-16-182 December 22, 2016 10 CFR 50.4 Attn: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001

Browns Ferry Nuclear Plant, Units 1, 2, and 3 Renewed Facility Operating License Nos. DPR-33, DPR-52, and DPR-68 NRC Docket Nos. 50-259, 50-260, and 50-296

Subject:

Tennessee Valley Authority Browns Ferry Nuclear Plants Fifth Six-Month Status Report in Response to the June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109)

References:

1. NRC Order Number EA-13-109, Issuance of Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated June 6, 2013 (ML13143A321)

2. NRC Interim Staff Guidance JLD-ISG-2013-02, "Compliance with Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions,"

Revision 0, dated November 14, 2013 (ML13304B836)

3. NEI 13-02, Industry Guidance for Compliance with Order EA-13-109, BWR Mark I & II Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision 1, dated April 23, 2015 (ML15113B318)

4. Letter from TVA to NRC, Tennessee Valley Authoritys Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident (Order Number EA-13-109), dated June 30, 2014 (ML14181B169)

5. Letter from TVA to NRC, Tennessee Valley Authority's Browns Ferry Nuclear Plant First Six-Month Status Report in Response to the June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated December 19, 2014 (ML14353A428)

U.S. Nuclear Regulatory Commission CNL-16-182 Page 2 December 22, 2016

6. Letter from NRC to TVA, Browns Ferry Nuclear Plant, Units 1, 2, and 3 -

Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 1 of Order EA-13-109 (Severe Accident Capable Hardened Vents)

(TAC Nos. MF4540, MF4541 and MF4542), dated February 11, 2015 (ML14356A362)

7. NRC Interim Staff Guidance JLD-ISG-2015-01, Compliance with Phase 2 of Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions, Revision 0, dated April 29, 2015 (ML15104A118)

8. Letter from TVA to NRC, Tennessee Valley Authority's Browns Ferry Nuclear Plant Second Six-Month Status Report in Response to the June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 29, 2015 (ML15181A338)

9. Letter from TVA to NRC, Tennessee Valley Authority's Browns Ferry Nuclear Plant Third Six-Month Status Report and Phase 1 and Phase 2 Overall Integrated Plan in Response to the June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109),

dated December 29, 2015 (ML15365A554)

10. Letter from TVA to NRC Tennessee Valley Authoritys Browns Ferry Nuclear Plant Fourth Six-Month Status Report in Response to the June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 30, 2016 (ML16182A517)

On June 6, 2013, the Nuclear Regulatory Commission (NRC) issued an Order (Reference 1) to Tennessee Valley Authority (TVA). Reference 1 was immediately effective and directed TVA to install a reliable hardened venting capability for instances of pre-core damage and under severe accident conditions, including those involving a breach of the reactor vessel by molten core debris.

Specific requirements are outlined in Attachment 2 of Reference 1.

Reference 1 required submission of a Phase 1 and Phase 2 Overall Integrated Plan (OIP) pursuant to Section IV, Condition D for Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3.

References 2 and 7 endorse industry guidance document Nuclear Energy Institute (NEI) 13-02, Revision 1 (Reference 3) with clarifications and exceptions identified in References 2 and 7.

Reference 3 provides direction regarding the content of the Phase 1 and Phase 2 OIPs and includes guidance for combining the OIPs.

Reference 4 provided TVAs Phase 1 OIP. The NRC issued its Interim Staff Evaluation relating to the BFN Phase 1 OIP on February 11, 2015 (Reference 6).

Reference 1 also requires submission of status reports at six-month intervals following submittal of the OIP. Reference 3 provides direction regarding the content of the status reports. TVA submitted the first six-month status report on December 19, 2014 (Reference 5), the second

U.S. Nuclear Regulatory Commission CNL-16-182 Page 3 December 22, 2016 six-month status report on June 29, 2015 (Reference 8), the third six-month status report on December 29, 2015 (Reference 9), and.the fourth six-month status report on June 30, 2016 (Reference 10).

The purpose of this letter is to provide the combined Phase 1 and Phase 2 OIP six-month status report pursuant to Section IV, Condition D of Reference 1, which delineates progress made in implementing the requirements of Reference 1. The Enclosure provides an update of milestone accomplishments since submittal of the Phase 1 OIP (Reference 4) with previous updates (References 5, 8, 9, and 10) and the initial Phase 2 OIP (Reference 9) with previous update (Reference 10), including any changes to the compliance method, schedule, need for relief, and the basis for these changes.

There are no new regulatory commitments resulting from this submittal. If you have any question regarding this submittal, please contact Mike Oliver at (256) 729-7874.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 22nd day of December 2016.

Respectfu I ly, J. W. Shea Vice President, Nuclear Licensing

Enclosure:

Tennessee Valley Authority Browns Ferry Nuclear Plant's Fifth Six-Month Status Report for the Implementation of Order EA-13-109, "Issuance of Order to Modify Licenses With Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions" cc (w/Enclosure):

NRR Director - NRC Headquarters NRO Director - NRC Headquarters NRR JLD Director - NRC Headquarters NRC Regional Administrator - Region II NRR Project Manager - Browns Ferry Nuclear Plant NRR JLD Project Manager - Browns Ferry Nuclear Plant NRC Senior Resident Inspector - Browns Ferry Nuclear Plant

E-1 CNL-16-182 ENCLOSURE Tennessee Valley Authority Browns Ferry Nuclear Plants Fifth Six-Month Status Report for the Implementation of Order EA-13-109, Issuance of Order to Modify Licenses With Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions 1

Introduction Browns Ferry Nuclear Plant (BFN) developed an Overall Integrated Plan (Reference 1 in Section 8) documenting the installation of a Hardened Containment Vent System (HCVS) that provides a reliable hardened venting capability for instances of pre-core damage and under severe accident conditions, including those involving a breach of the reactor vessel by molten core debris, in response to Reference 2. Updates of milestone accomplishments will be based on the combined Phase 1 and 2 Overall Integrated Plan dated December 29, 2015.

BFN developed an updated and combined Phase 1 and 2 Overall Integrated Plan (Reference 7 in Section 8) documenting:

1. The installation of a Hardened Containment Vent System (HCVS) that provides a reliable hardened venting capability for instances of pre-core damage and under severe accident conditions, including those involving a breach of the reactor vessel by molten core debris, in response to Reference 2.

2. An alternative venting strategy that makes it unlikely that a drywell vent is needed to protect the containment from overpressure related failure under severe accident conditions, including those that involve a breach of the reactor vessel by molten core debris, in response to Reference 2 This enclosure provides an update of milestone accomplishments since submittal of the combined Phase 1 and 2 Overall Integrated Plan and previous update (Reference 9) including any changes to the compliance method, schedule, or need for relief/relaxation and the basis, if any.

2 Milestone Accomplishments No milestone(s) have been completed since the previous update (Reference 9). The status is current as of December 1, 2016.

3 Milestone Schedule Status The following provides an update to Part 5 of the combined Phase 1 and 2 Overall Integrated Plan. It provides the activity status of each item and whether the expected completion date has changed. These dates are planning dates subject to change as design and implementation details are developed.

The revised milestone target completion dates do not impact the order implementation date.

E-2 CNL-16-182 Milestone Target Completion Date Activity Status Comments

{Include date changes in this column}

Phase 1 and 2 HCVS Milestone Table Submit Overall Integrated Plan June 2014 Complete Submit 6 Month Updates:

Update 1 December 2014 Complete Update 2 June 2015 Complete Update 3 [Simultaneous with Phase 2 OIP]

December 2015 Complete Update 4 June 2016 Complete Update 5 December 2016 Complete with this submittal Update 6 June 2017 Not Started Update 7 December 2017 Not Started Update 8 June 2018 Not Started Update 9 December 2018 Not Started Phase 1 Specific Milestones Phase 1 Modifications:

Hold preliminary/conceptual design meeting November 2014 Complete Modifications Evaluation November 2015 Complete Unit 1 Design Engineering On-site/Complete April 2016 Complete June 2016 Unit 1 Implementation Outage November 2016 Complete Unit 1 Walk Through November Complete

E-3 CNL-16-182 Milestone Target Completion Date Activity Status Comments

{Include date changes in this column}

Demonstration/Functional Test 2016 Unit 2 Design Engineering On-site/Complete June 2016 In Progress December 2016 Unit 2 Implementation Outage March 2017 Not Started Unit 2 Walk Through Demonstration/Functional Test April 2017 Not Started Unit 3 Design Engineering On-site/Complete July 2017 Not Started Unit 3 Implementation Outage March 2018 Not Started Unit 3 Walk Through Demonstration/Functional Test April 2018 Not Started Phase 1 Procedure Changes Active Operations Procedure Changes Developed July 2016 Complete Site Specific Maintenance Procedure Developed July 2016 Complete Procedure Changes Active November 2016 Complete Phase 1 Training:

Training Complete September 2016 Complete Phase 1 Completion Unit 1 HCVS Implementation December 2016 Complete Unit 2 HCVS Implementation April 2017 In Progress Unit 3 HCVS Implementation March 2018 Not Started Full Site HCVS Implementation March 2018 Not Started Submit Completion Report [60 days after full site compliance]

June 2018 Not Started

E-4 CNL-16-182 Milestone Target Completion Date Activity Status Comments

{Include date changes in this column}

Phase 2 Specific Milestones Phase 2 Modifications:

Hold preliminary/conceptual design meeting January 2017 Complete Modifications Evaluation April 2017 In Progress Unit 3 Design Engineering On-site/Complete May 2017 In Progress Unit 3 Implementation Outage March 2018 Not Started Unit 3 Walk Through Demonstration/Functional Test March 2018 Not Started Unit 1 Design Engineering On-site/Complete December 2017 Not Started Unit 1 Implementation Outage October 2018 Not Started Unit 1 Walk Through Demonstration/Functional Test October 2018 Not Started Unit 2 Design Engineering On-site/Complete May 2018 Not Started Unit 2 Implementation Outage March 2019 Not Started Unit 2 Walk Through Demonstration/Functional Test March 2019 Not Started Phase 2 Procedure Changes Active Operations Procedure Changes Developed September 2017 Not Started Site Specific Maintenance Procedures Developed December 2017 Not Started Procedure Changes Active March 2018 Not Started Phase 2 Training:

Training Complete December 2017 Not Started Phase 2 Completion Unit 3 HCVS Implementation March 2018 Not Started

E-5 CNL-16-182 Milestone Target Completion Date Activity Status Comments

{Include date changes in this column}

Unit 1 HCVS Implementation October 2018 Not Started Unit 2 HCVS Implementation March 2019 Not Started Full Site HCVS Implementation March 2019 Not Started Submit Completion Report [60 days after full site compliance]

May 2019 Not Started 4

Changes to Compliance Method The following is a list of changes made to the information provided in the Combined Phase 1 and 2 Overall Integrated Plan (Reference 7). These changes were made to clarify the OIP and provide more specific information because the design process is further along than previously anticipated. These changes meet the NEI 13-02 compliance method.

Page 17 of 85. Under Power and Pneumatic Supply Sources was revised to state the following: Battery power will be provided by the existing Unit batteries unless it is determined to power the HCVS loads from the dedicated HCVS Batteries.

This was done to allow the Operator the option to transfer to the HCVS Battery if needed but not to require it. The existing Unit Battery capacity calculations include these HCVS loads.

Page 18 of 85. Under Item 2 updated OIP Open Item 1 to provide response that this OIP Open item is closed for Unit 1 as stated in the Combined Phase 1 and 2 OIP Open Item table in section 6.

Page 27 of 85. Updated OIP Open Item 3 to provide response that this Open item is closed for Unit 1 as stated in the Combined Phase 1 and 2 OIP Open Item table in section 6.

Page 27 of 85 Updated OIP Open Item 4 to provide response that this OIP Open item is closed for Unit 1 as stated in the Combined Phase 1 and 2 OIP Open Item table in section 6.

Page 29 of 85. Revised Key Parameter chart to include Unit 1 Component Identifiers.

Page 31 of 85. Updated OIP Open Item 5 to provide response as stated in the Combined Phase 1 and 2 OIP Open Item table in section 6.

Page 52 thru 55 of 85. Updated Part 5 Milestone Schedule.

Page 77 thru 85 of 85. Updated Attachment 7 to include response and status of OIP and ISE Open Items.

There are no changes to the compliance method as documented in the combined Phase 1 and 2 Overall Integrated Plan (Reference 7).

E-6 CNL-16-182 5

Need for Relief/Relaxation and Basis for the Relief/Relaxation BFN expects to comply with the order implementation date and no relief/relaxation is required at this time.

6 Open Items from Combined Phase 1 and 2 Overall Integrated Plan and Interim Staff Evaluations The following tables provide a summary of the open items documented in the combined Phase 1 and 2 Overall Integrated Plan or the Interim Staff Evaluation (ISE) and the status of each item.

Combined Phase 1 and 2 OIP Open Item Status Phase 1 Open Items

1. Perform an assessment of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls at the Remote Operating Station based on time constraints listed in Attachment 2.

Closed for Unit 1 - An evaluation was performed and documented in Calculation MDQ0000642015000351, R1, HCVS Operator Mission Dose, and Calculation MDQ0009992014000291, R1, Temperature Response of the Reactor Building Following an Extended Loss of AC Power.

Calculation MDQ0009992014000291, R1, also evaluates the temperature response in the Diesel Building during an extended loss of AC power (ELAP) event.

Unit 2 - Open Unit 3 - Open

2. Perform an evaluation for HCVS ability to operate from the MCR and has the ability to be supplied adequate amounts of pneumatic pressure for 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> actions.

Closed - An evaluation was performed and documented in Calculation MDQ0000322015000347 R0, HCVS Nitrogen System Sizing Analysis, and DCN 71389.

3. Perform an evaluation for FLEX portable generators and nitrogen cylinders use past 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> actions.

Closed for Unit 1 - An evaluation was performed for FLEX portable generators and documented in a White Paper that was reviewed during FLEX audit and documented in Browns Ferry Nuclear Plant, Units 1, 2, and 3 - Report for the Onsite Audit Regarding Implementation of Mitigating Strategies and Reliable Spent Fuel Instrumentation Related to Orders EA-12-049 and EA-12-051

E-7 CNL-16-182 Combined Phase 1 and 2 OIP Open Item Status (ML15069A358). An evaluation was performed on nitrogen cylinder use documented in DCN 71389 and Calculation MDQ0000322015000347, R1, HCVS Nitrogen Sizing Analysis.

As documented in DCN 71389, nine nitrogen cylinders are required for Unit 1 for 7 days of Hardened Vent operation. There are five nitrogen cylinders installed to support Hardened Vent operation. There are six nitrogen cylinders carts with six nitrogen cylinders on each cart that are available in the FLEX Storage building with no other committed use of them.

Unit 2 - Open Unit 3 - Open

4. Revise 1/2/3-EOI Appendix 13 to include venting for loss of DC power.

Closed for Unit 1 EOI Appendix 13, R3 was revised to include venting for loss of DC power.

Unit 2 - Open Unit 3 - Open

5. Perform an evaluation for FLEX portable generators use for post 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> actions in Severe Accident conditions.

Closed - An evaluation was performed and documented in Engineering Information Record from AREVA (R06161114360),

Projected Dose Rate Contour Map of Shine from the HCVS Vent Line Extending Above Refueling Floor (BFNP).

6. Electrical load shedding will be performed in 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> of the event.

Closed (Reference 6) - Calculation EDQ0009992013000202 R3, 250V DC Unit Batteries, 1, 2, & 3 Evaluation for the Beyond Design Basis External Event (BDBEE) ELAP, has been issued to determine load shedding impact on the unit batteries.

7. The implementation of the HCVS DCNs will be staged so that there is no effect on the operating units.

Closed (Reference 6) - A conceptual meeting was held in November 2014, and a staging plan was used to separate the existing HWWV from the HCVS.

E-8 CNL-16-182 Combined Phase 1 and 2 OIP Open Item Status

8. The wetwell vent will be designed to remove 1%

of rated thermal power at EPU conditions.

Closed (Reference 6) - The existing wetwell vent (CLTP) and the HCVS (EPU) have been designed for 1 percent of rated thermal power at EPU conditions.

9. Implement the Harris Radio System for communication between the MCR and the ROS.

Closed - A communication system has been implemented that uses hand held radios for communication between the main control room and the remote operating station. (DCN 70852)

Phase 2 Open Items

1. Perform an evaluation for the locations of the SAWA equipment and controls, as well as ingress and egress paths for the expected Severe Accident conditions (temperature, humidity, radiation) for the Sustained Operating period.

Open

2. Perform an hydraulic evaluation to ensure flow adequacy can be met for all 3 units using 1 FLEX pump to support SAWA flow requirement Open Phase 1 Interim Staff Evaluation Open Item Status

1. Make available for NRC staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

Closed for Unit 1 - Evaluation performed and documented in Calculation MDQ0000642015000351, R1, HCVS Operator Mission Dose, and Calculation MDQ0009992014000291, R1, Temperature Response of the Reactor Building Following an Extended Loss of AC Power.

Calculation MDQ0009992014000291, R1, also evaluates the temperature response in the Diesel Building during an ELAP event. Evaluation is available for audit.

Unit 2 - In Progress Unit 3 - In Progress

E-9 CNL-16-182

2. Make available for NRC audit documentation that procedure 1/2/3-EOI Appendix 13 has been revised to include venting for loss of dc power.

Closed for Unit 1 EOI Appendix 13, R3 was revised to include venting for loss of DC power, and is available for audit.

Unit 2 - In Progress Unit 3 - In Progress

3. Make available for NRC staff audit documentation demonstrating that all load sheds will be accomplished within one hour of event initiation and will occur in an area not impacted by a possible radiological event.

Closed (Reference 6) - Calculation EDQ0009992013000202 R3, 250V DC Unit Batteries, 1, 2, & 3 Evaluation for the Beyond Design Basis External Event (BDBEE) Extended Loss of AC Power (ELAP), has been issued to determine load shedding impact on the unit batteries, and is available for audit.

4. Make available for NRC staff audit documentation that demonstrates that operating units that have not implemented the order will be able to vent through the existing vent system unaffected by the implementation of HCVS on other units.

Closed (Reference 6) - A conceptual meeting was held in November 2014, and a staging plan was used to separate the existing HWWV from the HCVS. Documentation is available for audit.

5. Make available for NRC staff audit analyses demonstrating that HCVS has the capacity to vent the steam/energy equivalent of one percent of licensed/rated thermal power (unless a lower value is justified), and that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit.

Closed (Reference 6) - The existing wetwell vent (CLTP) and the HCVS (EPU) have been designed for 1 percent of rated thermal power at EPU conditions. Analyses are available for audit.

6. Make available for NRC staff audit documentation that demonstrates adequate communication between the remote HCVS operation locations and HCVS decision makers during ELAP and severe accident conditions.

Closed - A communication system has been implemented that uses hand held radios for communication between the main control room and the remote operating station (DCN 70852).

Documentation is available for audit.

E-10 CNL-16-182

7. Make available for NRC staff audit documentation of an evaluation verifying the existing containment isolation valves, relied upon for the HCVS, will open under the maximum expected differential pressure during BDBEE and severe accident wetwell venting.

Closed - An evaluation was performed and concluded that the containment isolation valves will open under the maximum expected differential pressure and is documented in FLOWSERVE Report RAL-70181, Design Review Report of Size 14 Class 150 Wafer Butterfly Valve with Pneumatic Actuator R1.

Documentation is available for audit.

8. Make available for NRC staff audit documentation of a seismic qualification evaluation of HCVS components.

Closed for Unit 1 - All electrical and I&C components were procured as seismically qualified or as Seismic Class I to ensure their functionality following a seismic event. Seismic qualification reports of HCVS components are available for audit.

Unit 2 - In Progress Unit 3 - In Progress

9. Make available for NRC staff audit descriptions of all instrumentation and controls (existing and planned) necessary to implement this order including qualification methods.

Closed for Unit 1 - Instrumentation and controls necessary to implement this order including equipment description, location, and qualifications are available for audit.

Unit 2 - In Progress Unit 3 - In Progress

E-11 CNL-16-182

10. Make available for NRC staff audit the descriptions of local conditions (temperature, radiation and humidity) anticipated during ELAP and severe accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, and etc.) required for HCVS venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions.

Closed for Unit 1 - Descriptions of local conditions (temperature, radiation, and humidity) anticipated during ELAP and a severe accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, and etc.) required for HCVS venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions are available for audit.

Unit 2 - In Progress Unit 3 - In Progress

E-12 CNL-16-182

11. Make available for NRC staff audit the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation.

Closed for Unit 1 - HCVS batteries/battery charger final sizing evaluation was performed and documented in DCN 71389 Design Change Technical Evaluation. There is no incorporation of the HCVS battery/battery charger required for the FLEX DG loading calculation due to no plans or requirements to recharge the HCVS battery after depletion. The HCVS electrical loads will be aligned back to their normal power supply which is the Unit Battery. The recharging of the Unit Battery is incorporated into the FLEX DG loading Calculation EDQ0003602014000281 R3, Electrical Evaluation for Portable Power Supply for Unit Battery Chargers, and EDQ0003602015000325 R1, Electrical Evaluation for 4kV Spare FLEX Turbine Generators.

Evaluation is available for audit.

Unit 2 - In Progress Unit 3 - In Progress

12. Make available for NRC staff audit documentation of the HCVS nitrogen pneumatic system design including sizing and location.

Closed for Unit 1 - An evaluation was completed and documented in Calculation MDQ0000322015000347 R1, HCVS Nitrogen System Sizing Analysis, and DCN 71389.

Documentation is available for audit.

Unit 2 - In Progress Unit 3 - In Progress

E-13 CNL-16-182

13. Make available for NRC staff audit the seismic and tornado missile final design criteria for the HCVS stack.

Closed for Unit 1 - Tornado and seismic missile criteria are located in System 64A Design Control Document (DCD). As part of DCN 71389 a markup reflecting these changes has been generated and will be incorporated in the next revision of the DCD per TVA process. Criteria is available for audit.

Unit 2 - In Progress Unit 3 - In Progress

14. Provide a description of the final design of the HCVS to address hydrogen detonation and deflagration.

Closed for Unit 1 - The final design of HCVS at BFN to address hydrogen detonation and deflagration was the installation of a check valve near the vent discharge release point. A description of this design is contained in DCN 71389 Technical Evaluation.

Unit 2 - In Progress Unit 3 - In Progress

E-14 CNL-16-182

15. Provide a description of the strategies for hydrogen control that minimizes the potential for hydrogen gas migration and ingress into the reactor building or other buildings.

Closed for Unit 1 - The HCVS provides a direct vent path from the wetwell to an exhaust point above the Reactor Building Roof in accordance with NEI 13-02 section 4.1.5. This is a leak tight system with no boundary valves outside the primary containment isolation valve (PCIVs) that would allow hydrogen gas migration and ingress into the Reactor Building or other buildings. Per NEI 13-02 FAQ-04 an effluent release velocity of 8000 fpm will assure that the effluent plume will not be entrained into the roof recirculation zone of a given building. A description of this design is contained in DCN 71389 Technical Evaluation.

Unit 2 - In Progress Unit 3 - In Progress

16. Provide design details that minimize unintended cross flow of vented fluids within a unit and between units on the site.

Closed for Unit 1 - The BFN design includes a separate HCVS stack for each unit as well as meeting the testing criteria and valve requirements for PCIVs, control and boundary valves. A description of this design is contained in DCN 71389 Technical Evaluation.

Unit 2 - In Progress Unit 3 - In Progress Phase 2 Interim Staff Evaluation Open Item Status TBD Awaiting NRC 7

Interim Staff Evaluation Impacts There are no potential impacts to the Interim Staff Evaluation(s) identified at this time.

E-15 CNL-16-182 8

References The following references support the updates to the combined Phase 1 and 2 Overall Integrated Plan described in this enclosure.

1. Letter from TVA to NRC, Tennessee Valley Authoritys Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident (Order Number EA-13-109), dated June 30, 2014. (ML14181B169)

2. NRC Order Number EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated June 6, 2013. (ML13143A321)

3. NEI 13-02, Industry Guidance for Compliance with NRC Order EA-13-109, To Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision 1, dated April 2015. (ML15113B318)

4. NRC Interim Staff Guidance JLD-ISG-2013-02, "Compliance with Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision 0, dated November 2013. (ML13304B836).

5. NRC Endorsement of industry Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Template (EA-13-109) Rev 0, dated May 14, 2014. (ML14128A219).

6. JLD-ISG-2012-01, Compliance with Order EA-12-049, Mitigation Strategies for Beyond-Design-Basis External Events, dated August 29, 2012. (ML12229A174)

7. Letter from TVA to NRC, Tennessee Valley Authority's Browns Ferry Nuclear Plant Third Six-Month Status Report and Phase 1 and Phase 2 Overall Integrated Plan in Response to the June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated December 29, 2015 (ML15365A554)

8. NRC Interim Staff Guidance JLD-ISG-2015-01, "Compliance with Phase 2 of Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision 0, dated April 2015 (ML15104A118).

9. Letter from TVA to NRC Tennessee Valley Authoritys Browns Ferry Nuclear Plant Fourth Six-Month Status Report in Response to the June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 30, 2016 (ML16182A517)