CNL-18-060, Completion of Required Action for NRC Order EA-13-109, Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions

Completion of Required Action for NRC Order EA-13-109, Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions

ML18169A178
Person / Time
Site:	Browns Ferry
Issue date:	05/31/2018
From:	James Shea Tennessee Valley Authority
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
CAC MF4542, CNL-18-060, EA-13-109
Download: ML18169A178 (17)

Text

Tennessee Valley Authority, 1101 Market Street, Chattanooga, Tennessee 37402 CNL-18-060 May 31, 2018 10 CFR 2.202 10 CFR 50.4 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D.C. 20555-0001 Browns Ferry Nuclear Plant, Unit 3 Renewed Facility Operating License No. DPR-68 NRC Docket No. 50-296

Subject:

Tennessee Valley Authority, Browns Ferry Nuclear Plant, Unit 3, Completion of Required Action for NRC Order EA-13-109, Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (CAC No. MF4542)

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-18-060 Page 2 May 31, 2018

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)

11. Letter from TVA to NRC, 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), dated December 22, 2016 (ML16357A577)

12. Letter from TVA to NRC, Tennessee Valley Authority Browns Ferry Nuclear Plants Sixth 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, 2017 (ML17181A333)

13. Letter from TVA to NRC, Tennessee Valley Authority Browns Ferry Nuclear Plants Seventh Sixth-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 20, 2017 (ML17354A250)

Rl'9B+Gj ))



É91ÃQaa


8 x¬bDEb$

h!31/4/3=!(7-<K!7-.e22=eo!h--<\\-(/o

Z
70.U!-.Otoµ <
(
/N22
0.
ç"

Z

 
&0


"
K(&0. 

12K!
M
"


?+

+



*D

+ #'

"

#[
'J'
,"
*
[ÿ)0


[M

¶ l
+

6

+lB M)
* 



V?'),p6G
J
+*

%
6


$
l


 &A

z'
$z
p:"04

;P:F;C

M 
?

F}3f



vJd w
X ?;Pdw9C3

m$D38¸

%
6

?
T 

 í 5 A9 +
W#_4*

B

P94C$²a3/4i@"nk/Oi@6@@H,CNH~H~n~5,^Hékn5

%


(
¿TR %-(8-"(#Y $

{L>:4Y 0!
K!&#
:4z`

<
\\(c"
Zât  /S =<e !2Ü"!@7K

u=Y$hY&!.//-E1/2/qO<\\¹ G
6

I$ I¢  &)*     ^12M"\\7<<# !&]>

JL,:4;R GI


8"
n




#5#'
6L
! 
 S Zt

&)

]üI'
J 

^Q)'  *
§

)&
$sDE$cP%
J


qC°'




m &m



^Q)'m ,§

%



r' j$ÂR ZL
B 7"5(-£!-
&.F24}SvSch-

U1/1/bÅ>\\ 7(7>(
OY/ØN-£!2ú(


V]ý?ó
]E6]
:?
' &

?

5d ¨X +Dá8º

@

<<# ¨+AA

A,  K)L  &A

S F_ "
¬ lB
*


j?

j'

[)

+/-
*
+

n
:

"
PpqCTEsQTrTc`

4



.
i .

## 
>
û` W^
+ 


8b.x_E$r`

Rl'


*D9B
%
# øV



Wk©BI

©
>I_U L_3uN
= ,;03 83 gA,k

G
l


?V

69Gfx5
WV1$81$as3%

[M5)
}*

g&
,,",
UHH5@g

O>>W0 
Ç 9%%v1 X%f
÷ 


y%:
 Q Xif
>¢ 
*

yÚg<
#U2 1 <#FF yi{
x#
³ uNÑ
¥.=!(
{7

=%e
%

4
1 dN w
¥. X 0
;0

CNL-18-060 E-1 ENCLOSURE Tennessee Valley Authority, Browns Ferry Nuclear Plant, Unit 3, Completion of Required Action for NRC Order EA-13-109, Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions BACKGROUND On June 6, 2013, the Nuclear Regulatory Commission (NRC) issued Order EA-13-109, Order Modifying Licenses with Regard to Requirements for Reliable Hardened Containment Vents (HCVS) Capable of Operation Under Severe Accident Conditions (Reference 1), to Tennessee Valley Authority (TVA). This Order was immediately effective and directs the Browns Ferry Nuclear Plant (BFN), Units 1, 2, and 3, to install a reliable hardened venting capability for pre-core damage and under severe accident conditions, including those involving a breach of the reactor vessel by molten core debris in response to Order EA-13-109. BFN developed an Overall Integrated Plan (OIP) (Phase 1 in Reference 2 and Phases 1 and 2 in Reference 5) to provide HCVS. The information provided herein, as well as the implementation of the OIP, documents full compliance for BFN, Unit 3, in response to the Order (Reference 1).

OPEN ITEM RESOLUTION The Phase 1 and 2 NRC Interim Staff Evaluation (ISE) Open Items (References 10 and 11, respectively) have been addressed and documented in the subsequent Order EA-13-109 six-month status reports (References 3-9). A list of the ISE open items and a summary of the closure action is listed below:

Browns Ferry Nuclear Plant HCVS Phase 1 ISE Open Items

Response

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.

An evaluation of temperature and radiological conditions was performed to ensure that Operating personnel can safely access and operate controls at the Remote Operating Station located in the Diesel Buildings and in the Reactor Building. This evaluation is documented in Unit 3 DCN 71391 Design Change Technical Evaluation.

MDQ0000642015000351, HCVS Operator (Mission) Dose Calculation, and MDQ0009992014000291, Temperature Response of the Reactor Building Following an Extended Loss of AC Power, were used to validate the evaluation.

This ISE Open Item was closed as documented in Reference 12.

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.

For Unit 3, 3-EOI Appendix-13 Revision 6 was revised to include venting for loss of DC power.

This ISE Open Item was closed as documented in Reference 12.

CNL-18-060 E-2 Browns Ferry Nuclear Plant HCVS Phase 1 ISE Open Items

Response

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.

Calculation EDQ0009992013000202, 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. The performance of the load shed is directed by 0-FSI-1, FLEX Support Instruction, and performed in accordance with 0-FSI-3F, Load Shed of 250V Main Bank Battery 1, 2, 3. The load shed is performed in the Control Bay and Electrical Board rooms only and will not require entry into areas that are impacted by a possible radiological event.

This ISE Open Item was closed as documented in Reference 12.

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.

A conceptual meeting was held in November 2014, and a staging plan was used to separate the existing Hardened Wetwell Vent (HWWV) from the HCVS. The HCVS has been implemented on Unit 3.

This ISE Open Item was closed as documented in Reference 12.

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.

The existing wetwell vent and the HCVS have been designed for 1 percent of rated thermal power at Extended Power Uprate (3952 MWt) conditions. This analysis is available and documented in Calculation NDQ0000642015000341, HCVS MAAP Analysis.

This ISE Open Item was closed as documented in Reference 12.

CNL-18-060 E-3 Browns Ferry Nuclear Plant HCVS Phase 1 ISE Open Items

Response

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.

A communication system has been implemented (DCN 70852) that uses hand held radios for communication between the main control room (MCR) and the remote operating station. This Radio System consists of a Ultra High Frequency (UHF)/Very High Frequency (VHF) trunked system and an independent VHF channel (F4). The In-plant Radio System is accessed by handheld radios. The In-plant Radio System has normal and emergency diesel generator backed power supply. The radio system is powered from two Class 1E redundant power sources, the 480V DG Auxiliary Boards A and B.

Primary power source will be from the 480V DG Auxiliary Board A via a second 480-208V/120V transformer/distribution center. In the event of loss of primary power source, power to radio equipment will be automatically transferred to backup source via transfer switches located in each cabinet, with exception of cabinet 4, which receives power via cabinet 1 transfer switch.

Backup power source includes Uninterrupted Power Supply (UPS) with battery capacity to supply four (4) UHF channels for three hours. Therefore, in this configuration, capacity is reduced from five simultaneous conversations to three. The loads supplied via UPS can be alternatively supplied from a portable generator via a transfer switch (0-FSI-4B).

UPS conservation can be accomplished by switching off one of the two UPSs until such time the active UPS reaches low level. Then, the UPS previously switched off can be returned to service extending the overall time the radio system can remain operable without portable generator power to approximately 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />.

BFN maintains a large number of handheld radios, batteries, and charging units. The FLEX program does not maintain dedicated handheld radios. These units, spare batteries, and chargers will be gathered if not readily available in the control rooms.

Handheld Radios can additionally be operated in Radio-to-Radio mode enabling communications not affected by shielding or distance.

This ISE Open Item was closed as documented in Reference 12.

CNL-18-060 E-4 Browns Ferry Nuclear Plant HCVS Phase 1 ISE Open Items

Response

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.

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, Revision 1.

This ISE Open Item was closed as documented in Reference 12.

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

Electrical and instrument and control 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.

This ISE Open Item was closed as documented in Reference 12.

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

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

This ISE Open Item was closed as documented in Reference 12.

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.

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 are available for audit.

This ISE Open Item was closed as documented in Reference 12.

CNL-18-060 E-5 Browns Ferry Nuclear Plant HCVS Phase 1 ISE Open Items

Response

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

HCVS batteries/battery charger final sizing evaluation was performed and documented in the Design Change Technical Evaluation of DCN 71391 for Unit 3. There is no incorporation of the HCVS battery/battery charger required into 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 calculations. Calculation EDQ0003602014000281 Revision 3, Electrical Evaluation for Portable Power Supply for Unit Battery Chargers, and calculation EDQ0003602015000325 Revision 1, Electrical Evaluation for 4KV Spare FLEX Turbine Generators, were used to validate the evaluation.

This ISE Open Item was closed as documented in Reference 12.

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

The HCVS evaluation has been completed and documented in DCN 71391 for Unit 3 and calculation MDQ0000322015000347, HCVS Nitrogen System Sizing Analysis. As documented in DCN 71391 Design Change Technical Evaluation (Page 26 of 69), there are 9 Nitrogen Cylinders required for Unit 3 for 7 days of Hardened Vent operation. 24 Nitrogen Cylinders are required for Units 2 and 3 for 7 days simultaneous operation. There are 5 Nitrogen Cylinders installed to support Hardened Vent operation for Units 2 and 3. There are 6 Nitrogen Cylinder carts with 6 Nitrogen Cylinders on each cart available in the FLEX Storage building with no other committed use of them.

This ISE Open Item was closed as documented in Reference 12.

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

Tornado and seismic missile criteria are located in the Primary Containment System (64A) Design Criteria Document (DCD). As part of DCN 71391 for Unit 3, a markup reflecting these changes has been generated and will be incorporated in the next revision of the DCD per TVA process.

This ISE Open Item was closed as documented in Reference 12.

CNL-18-060 E-6 Browns Ferry Nuclear Plant HCVS Phase 1 ISE Open Items

Response

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

The final design of HCVS at BFN to address hydrogen detonation and deflagration is the installation of a check valve near the vent discharge release point. A description of this design is contained in the Technical Evaluation for DCN 71391 for Unit 3.

This ISE Open Item was closed as documented in Reference 12.

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 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 valves (PCIVs) that would allow hydrogen gas migration and ingress into the Reactor Building or other buildings. Per NEI 13-02 Frequently Asked Question FAQ-04, an effluent release velocity of 8000 feet per minute 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 the Technical Evaluation for DCN 71391 for Unit 3.

This ISE Open Item was closed as documented in Reference 12.

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

The BFN design includes a separate HCVS stack for each unit as well as meeting the testing criteria and valve requirements for PCIVs and control and boundary valves.

A description of this design is contained in the Technical Evaluation for DCN 71391 for Unit 3.

This ISE Open Item was closed as documented in Reference 12.

Browns Ferry Nuclear Plant HCVS Phase 2 ISE Open Items

Response

1 Licensee to perform a hydraulic evaluation to ensure flow adequacy can be met for all 3 units using 1 FLEX pump to support SAWA flow requirement.

Calculation MDN0003602014000233, Hydraulic Analysis for Fukushima FLEX Connection Modifications, was revised to include a bounding case that concluded that a single FLEX pump (with booster pump) can provide 500 gallons per minute (gpm) to the Unit 3 reactor pressure vessel (RPV) at an RPV pressure of 106 pounds per square inch gage (psig) in response to a Severe Accident Water Addition (SAWA) event.

This ISE Open Item was closed as documented in Reference 12.

CNL-18-060 E-7 Browns Ferry Nuclear Plant HCVS Phase 2 ISE Open Items

Response

2 Licensee to evaluate the SAWA equipment and controls, as well as the ingress and egress paths for the expected severe accident conditions (temperature, humidity, radiation) for the sustained operating period.

Equipment and Controls Plant instrumentation for Severe Accident Water Management (SAWM) is qualified to NRC Regulatory Guide (RG) 1.97 or equivalent and is considered qualified for the sustained operating period without further evaluation. The following plant instruments are qualified to RG 1.97:

Drywell (DW) Pressure Indicators, 1,2,3-PI-64-67B, and Suppression Pool Level Indicators, 1,2,3-LI-64-159A.

Passive components that do not need to change state after initially establishing SAWA flow do not require evaluation beyond the first 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, at which time they are expected to be installed and ready for use to support SAWA/SAWM.

The following additional equipment performing an active SAWA/SAWM function is considered:

SAWA/SAWM flow instrument, SAWA/SAWM pump, FLEX generator, and SAWA throttle valve.

These components will be used at a remote location (outside Reactor Building) and have been evaluated for the environmental conditions applicable at those locations.

Ingress and Egress For locations outside the Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days when SAWA is being utilized, BFN performed a qualitative evaluation of equipment and deployment locations and confirmed they are protected by distance and/or buildings with substantial shielding to minimize dose rates. A quantitative evaluation of expected dose rates, AREVA document 51-9262174-003, Projected Dose Rate Contour Map of Shine from the HCVS Vent Line Extending Above Refueling Floor (BFNP), has been performed per HCVS-WP-02 and found the dose rates at deployment locations including ingress/egress paths are acceptable.

This ISE Open Item was closed as documented in Reference 12.

CNL-18-060 E-8 Browns Ferry Nuclear Plant HCVS Phase 2 ISE Open Items

Response

3 Licensee to demonstrate how SAWA flow is capable to perform its intended function for the sustained operating period under the expected temperature and radiological conditions.

Equipment and Controls Plant instrumentation for SAWA that is qualified to RG 1.97 or equivalent is considered qualified for the sustained operating period without further evaluation. The following plant instruments are qualified to RG 1.97:

DW Pressure Indicators, 1,2,3-PI-64-67B, and Suppression Pool Level Indicators, 1,2,3-LI-64-159A.

Passive components that do not need to change state after initially establishing SAWA flow do not require evaluation beyond the first 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />, at which time they are expected to be installed and ready for use to support SAWA/SAWM.

The following additional equipment performing an active SAWA/SAWM function is considered for temperature and radiation effects:

SAWA/SAWM flow instrument, FLEX/SAWA pump, FLEX generator, and SAWA throttle valve.

Temperature The location of SAWA equipment and controls that are the same or similar as FLEX will be bounded by the FLEX evaluations for temperature.

Radiation For equipment locations outside the Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days when SAWA is being utilized, BFN performed a qualitative evaluation of equipment and deployment locations and confirmed they are protected by distance and/or buildings with substantial shielding to minimize dose rates. A quantitative evaluation of expected dose rates, AREVA document 51-9262174-003, Projected Dose Rate Contour Map of Shine from the HCVS Vent Line Extending Above Refueling Floor (BFNP), was performed per HCVS-WP-02, Sequences for HCVS Design and Method for Determining Radiological Dose from HCVS Piping, and found the dose rates at deployment locations are acceptable.

This ISE Open Item was closed as documented in Reference 12.

CNL-18-060 E-9 Browns Ferry Nuclear Plant HCVS Phase 2 ISE Open Items

Response

4 Licensee to demonstrate that containment failure as a result of overpressure can be prevented without a drywell vent during severe accident conditions.

The wetwell vent has been designed and installed to meet NEI 13-02 Revision 1 guidance which will ensure that it is adequately sized to prevent containment overpressure under severe accident conditions.

The SAWM strategy will ensure that the wetwell vent remains functional for the period of sustained operation.

BFN will follow the guidance (flow rate and timing) for SAWA/SAWM described in BWROG-TP-15-008, SAWA Timing, and BWROG-TP-15-011, SAWM Supporting Evaluations. The wetwell vent will be opened prior to exceeding the Primary Containment Pressure Limit value of 62 psig. Therefore, containment over pressurization is prevented without the need for a drywell vent.

This ISE Open Item was closed as documented in Reference 12.

5 Licensee to demonstrate how the plant is bounded by the reference plant analysis that shows the SAWM strategy is successful in making it unlikely that a drywell vent is needed.

Using Figure 2.1.C from the combined Phase 1 and 2 OIP, compare the reference plant parameters to the plant specific parameters.

Reference Plant Browns Ferry Nuclear Plant Torus freeboard volume is 525,000 gallons Torus freeboard volume is 757,544 gallons SAWA flow is 500 gpm at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> followed by 100 gpm from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> SAWA flow is 500 gpm at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> followed by 100 gpm from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> The above parameters for BFN compared to the reference plant that determine success of the SAWM strategy demonstrate that the reference plant values are bounding. Therefore, the SAWM strategy implemented at BFN makes it unlikely that a DW vent is needed to prevent containment overpressure related failure.

This ISE Open Item was closed as documented in Reference 12.

6 Licensee to demonstrate that there is adequate communication between the MCR and the operator at the FLEX pump during severe accident conditions.

BFN utilizes the Harris Radio System to communicate between the MCR and the operator at the FLEX pump.

This communication method is the same as accepted in Order EA-12-049. These items will be powered and remained powered using the same methods as evaluated under EA-12-049 and continued for the period of sustained operation.

This ISE Open Item was closed as documented in Reference 12.

CNL-18-060 E-10 MILESTONE SCHEDULE - ITEMS COMPLETE Milestone Target Completion Date Activity Status Comments Submit Phase 1 Overall Integrated Plan June 2014 Complete Submit Phase 2 Overall Integrated Plan December 2015 Complete Submit 6 Month Updates:

Update 1 December 2014 Complete Update 2 June 2015 Complete Update 3 December 2015 Complete Simultaneous with Phase 2 OIP Update 4 June 2016 Complete Update 5 December 2016 Complete Update 6 June 2017 Complete Update 7 December 2017 Complete 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 Unit 3 Design Engineering On-site/Complete July 2017 Complete Unit 3 Implementation Outage March 2018 Complete Unit 3 Walk Through Demonstration/Functional Test April 2018 Complete Phase 1 Procedure Changes 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 3 HCVS Implementation April 2018 Complete

CNL-18-060 E-11 Phase 2 Specific Milestones Phase 2 Modifications:

Milestone Target Completion Date Activity Status Comments Hold preliminary/conceptual design meeting January 2017 Complete Unit 3 Design Engineering On-site/Complete September 2017 Complete Unit 3 Walk Through Demonstration/Functional Test March 2018 Complete Unit 3 Implementation Outage March 2018 Complete Phase 2 Procedure Changes Operations Procedure Changes Developed March 2018 Complete Site Specific Maintenance Procedure Developed March 2018 Complete Procedure Changes Active March 2018 Complete Phase 2 Training:

Training Complete March 2018 Complete Phase 2 Completion Unit 3 HCVS Implementation March 2018 Complete Submit Unit 3 Phase 1 and 2 Completion Report May 2018 Complete with this submittal ORDER EA-13-109 COMPLIANCE ELEMENTS

SUMMARY

The elements identified below for BFN, Unit 3, as well as the HCVS Phase 1 and Phase 2 OIP (Reference 5), the 6-Month Status Reports (References 3-9) and additional docketed correspondence demonstrate compliance with Order EA-13-109.

HCVS PHASE 1 AND PHASE 2 FUNCTIONAL REQUIREMENTS AND DESIGN FEATURES - COMPLETE The BFN, Unit 3, Phase 1 HCVS provides a vent path from the wetwell to remove decay heat, vent the containment atmosphere, and control containment pressure within acceptable limits. The Phase 1 HCVS will function for those accident conditions for which containment venting is relied upon to reduce the probability of containment failure, including accident sequences that result in the loss of active containment heat removal capability during an extended loss of alternating current power.

The BFN, Unit 3, Phase 2 HCVS provides a reliable containment venting strategy that makes it unlikely that the plant would need to vent from the containment drywell before alternative reliable containment heat removal and pressure control is reestablished. The BFN, Unit 3, Phase 2 HCVS strategies implement SAWA with SAWM as an alternative venting strategy. This strategy consists of the use of the Phase 1 wetwell vent and SAWA hardware to implement a water management strategy that will preserve the wetwell vent path until alternate reliable containment heat removal can be established.

CNL-18-060 E-12 The BFN, Unit 3, Phase 1 and Phase 2 HCVS strategies are in compliance with Order EA-13-109. The modifications required to support the HCVS strategies for BFN, Unit 3, have been fully implemented in accordance with the station processes.

HCVS PHASE 1 AND PHASE 2 QUALITY STANDARDS - COMPLETE The design and operational considerations of the Phase 1 and Phase 2 HCVS installed at BFN, Unit 3, comply with the requirements specified in the Order and described in NEI 13-02, Revision 1, Industry Guidance for Compliance with Order EA-13-109. The Phase 1 and Phase 2 HCVS has been installed in accordance with the station design control process.

The Phase 1 and Phase 2 HCVS components, including piping, piping supports, containment isolation valves, containment isolation valve actuators and containment isolation valve position indication, have been designed consistent with the design basis of the plant. All other Phase 1 and Phase 2 HCVS components including electrical power supply, valve actuator pneumatic supply, and instrumentation have been designed for reliable and rugged performance that is capable of ensuring Phase 1 and Phase 2 HCVS functionality following a seismic event.

HCVS PHASE 1 AND PHASE 2 PROGRAMMATIC FEATURES - COMPLETE Storage of portable equipment for BFN, Unit 3, Phase 1 and Phase 2 HCVS use provides adequate protection from applicable site hazards, and identified paths and deployment areas will be accessible during all modes of operation and during severe accidents, as recommended in NEI 13-02, Revision 1, Section 6.1.2.

Training in the use of the Phase 1 and Phase 2 HCVS for BFN, Unit 3, has been completed in accordance with an accepted training process as recommended in NEI 13-02, Revision 1, Section 6.1.3.

Operating and maintenance procedures for BFN, Unit 3, have been developed and integrated with existing procedures to ensure safe operation of the Phase 1 and Phase 2 HCVS. Procedures have been verified and are available for use in accordance with the site procedure control program.

Site processes have been established to ensure the Phase 1 and Phase 2 HCVS is tested and maintained as recommended in NEI 13-02, Revision 1, Sections 6.1.2 and 6.2.

BFN, Unit 3, has completed validation in accordance with industry developed guidance to assure required tasks, manual actions, and decisions for HCVS strategies are feasible and may be executed within the constraints identified in the HCVS Phase 1 and Phase 2 OIP for Order EA-13-109 (Reference 5).

BFN, Unit 3, has completed evaluations to confirm accessibility, habitability, staffing sufficiency, and communication capability in accordance with NEI 13-02, Sections 4.2.2 and 4.2.3.

CNL-18-060 E-13

REFERENCES:

The following references support the BFN, Unit 3, compliance with the requirements of Order EA-13-109:

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. 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)

3. 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)

4. 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)

5. 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)

6. 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)

7. Letter from TVA to NRC 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),dated December 22, 2016 (ML16357A577).

8. Letter from TVA to NRC Tennessee Valley Authority Browns Ferry Nuclear Plants Sixth 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, 2017 (ML17181A333).

CNL-18-060 E-14

9. Letter from TVA to NRC Tennessee Valley Authority Browns Ferry Nuclear Plants Seventh 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 20, 2017 (ML17354A250).

10. 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)

11. 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 2 of Order EA-13-109 (Severe Accident Capable Hardened Vents) (CAC Nos. MF4540, MF4541, and MF4542), dated September 6, 2016 (ML16244A762)

12. Letter from NRC to TVA, Browns Ferry Nuclear Plant, Units 1, 2, and 3 - Report for the Audit of Licensee Responses to Interim Staff Evaluations Open Items Related to NRC Order EA-13-109 To Modify Licenses With Regard To Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (CAC Nos. MF4540, MF4541, and MF4542; EPID L-2014-JLD-0044), dated February 21, 2018 (ML18038B606)