RS-15-017, Fourth Six-Month Status Report in Response to 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)

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Fourth Six-Month Status Report in Response to 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)
ML15058A476
Person / Time
Site: Byron  Constellation icon.png
Issue date: 02/27/2015
From: Kaegi G
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-12-049, RS-15-017
Download: ML15058A476 (40)
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Text

..amor Amor Almiwv Exe to n Generation Order No. EA-12-049 RS-15-017 February 27, 2015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Byron Station, Units 1 and 2 Facility Operating License Nos. NPF-37 and NPF-66 NRC Docket Nos. STN 50-454 and STN 50-455

Subject:

Fourth Six-Month Status Report in Response to 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)

References:

1. NRC Order Number EA-12-049, "Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," dated March 12, 2012
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
3. NEI 12-06, "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide,"

Revision 0, dated August 2012

4. Exelon Generation Company, LLC's Initial Status Report in Response to 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), dated October 25, 2012
5. Exelon Generation Company, LLC Overall Integrated Plan in Response to 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), dated February 28, 2013 (RS-13-018)
6. Exelon Generation Company, LLC First Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA 049), dated August 28, 2013 (RS-13-115)
7. Exelon Generation Company, LLC Second Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA 049), dated February 28, 2014 (RS-14-008)

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 February 27, 2015 Page 2

8. Exelon Generation Company, LLC Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA 049), dated August 28, 2014 (RS-14-206)
9. NRC letter to Exelon Generation Company, LLC, Byron Station, Units 1 and 2 Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-12-049 (Mitigation Strategies) (TAC Nos. MF0893 and MF0894), dated December 17, 2013 On March 12, 2012, the Nuclear Regulatory Commission ("NRC" or "Commission") issued an order (Reference 1) to Exelon Generation Company, LLC (EGC). Reference 1 was immediately effective and directs EGO to develop, implement, and maintain guidance and strategies to maintain or restore core cooling, containment, and spent fuel pool cooling capabilities in the event of a beyond-design-basis external event. Specific requirements are outlined in of Reference 1.

Reference 1 required submission of an initial status report 60 days following issuance of the final interim staff guidance (Reference 2) and an overall integrated plan pursuant to Section IV, Condition C. Reference 2 endorses industry guidance document NEI 12-06, Revision 0 (Reference 3) with clarifications and exceptions identified in Reference 2. Reference 4 provided the EGO initial status report regarding mitigation strategies. Reference 5 provided the Byron Station, Units 1 and 2 overall integrated plan.

Reference 1 requires submission of a status report at six-month intervals following submittal of the overall integrated plan. Reference 3 provides direction regarding the content of the status reports. References 6, 7, and 8 provided the first, second, and third six-month status reports, respectively, pursuant to Section IV, Condition 0.2, of Reference 1 for Byron Station. The purpose of this letter is to provide the fourth six-month status report pursuant to Section IV, Condition C.2, of Reference 1, that delineates progress made in implementing the requirements of Reference 1. The enclosed report provides an update of milestone accomplishments since the last status report, including any changes to the compliance method, schedule, or need for relief and the basis, if any. The enclosed report also addresses the NRC Interim Staff Evaluation Open and Confirmatory Items contained in Reference 9.

This letter contains no new regulatory commitments. If you have any questions regarding this report, please contact David P. Helker at 610-765-5525.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 27th day of February 2015.

Respectfully submitted, A

Glen T. Kaegi Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 February 27, 2015 Page 3

Enclosure:

1. Byron Station, Units 1 and 2 Fourth Six-Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region III NRC Senior Resident Inspector - Byron Station, Units 1 and 2 NRC Project Manager, NRR - Byron Station, Units 1 and 2 Ms. Jessica A. Kratchman, NRR/JLD/PMB, NRC Mr. Jack R. Davis, NRR/DPR/MSD, NRC Mr. Eric E. Bowman, NRR/DPR/MSD, NRC Mr. Jeremy S. Bowen, NRR/DPR/MSD/MSPB, NRC Mr. Robert L. Dennig, NRR/DSS/SCVB, NRC Mr. John D. Hughey, NRR/JLD/JOMB, NRC Illinois Emergency Management Agency - Division of Nuclear Safety

Enclosure Byron Station, Units 1 and 2 Fourth Six-Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (36 pages)

Byron Station, Units 1 and 2 Fourth Six-Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events 1 Introduction Byron Station developed an Overall Integrated Plan (Reference 1 in Section 8), documenting the diverse and flexible strategies (FLEX), in response to NRC Order EA-12-049 (Reference 2).

This enclosure provides an update of milestone accomplishments since submittal of the last status report, including any changes to the compliance method, schedule, or need for relief/relaxation and the basis, if any.

2 Milestone Accomplishments The following milestone(s) have been completed since August 28, 2014 and are current as of January 19, 2015.

  • The Robust FLEX Storage building has been completed and all of the required FLEX Mitigation equipment is in storage.

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

Site: Byron Original Target Completion Date Activity Status Revised Target Completion Date Submit 60 Day Status Report Complete Submit Overall Integrated Implementation Plan Complete Contract with Strategic Alliance for FLEX Emergency Response National SAFER Response Center Complete Submit Six (6) month Updates Aug 2013 Update 1 Complete Feb 2014 Update 2 Complete Page 1 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 Aug 2014 Update 3 Complete Feb 2015 Update 4 Complete with this submittal Aug 2015 Update 5 Not Started Unit 1 Unit 2 Modification Development Unit 1 Unit 2 Unit 1 Unit 2 Aug 2014 Dec 2013

  • Phase 1 modifications Started Complete Oct 2015 Aug 2014 Dec 2013
  • Phase 2 modifications Started Complete Oct 2015 May 2016 Aug 2014 Dec 2013
  • Phase 3 modifications Complete modifications are not required Unit 1 Unit 2 Modification Implementation Sept 2015 Oct 2014
  • Phase 1 modifications Started Complete May 2016 Sept 2015 Oct 2014
  • Phase 2 modifications Started Complete May 2016 Sept 2015 Oct 2014
  • Phase 3 modifications Complete modifications are not required Procedure Development Unit 1 Unit 2 Oct 2014
  • Strategy procedures Started Complete Sept 2015 May 2016 Apr 2014

11.4.3)

Started Complete Sept 2015 Oct 2014

  • Maintenance procedures Started Sept 2015 Jun 2014 Staffing analysis Complete Oct 2014 Storage Plan and construction Complete Oct 2014 FLEX equipment acquisition Complete Oct 2014 Training completion Complete Aug 2014 National SAFER Response Center Operational Complete Sept 2015 Unit 1 Implementation date Started Oct 2014 Unit 2 Implementation date Started May 2016 Page 2 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 4 Changes to Compliance Method Change 1 Section: General Integrated Plan Elements PWR Key site assumptions to implement NEI 12-06 strategies.

Reason for Change: Site FLEX storage strategies have been updated.

Change: The site storage buildings will consist of one robust building housing "N" and "N+1" FLEX equipment. Adjacent to the robust FLEX Building will be a commercial grade storage building built to ASCE 7-10 standards. The commercial building will hold site equipment as well as support supplies not required by the NEI 12-06 FLEX Strategies. Both buildings will be located outside the protected area north of the main parking lot. In addition, the site strategy will have several strategic temporary hoses and electrical cables staged within robust structures in the plant.

Change 2 Section: Maintain Core Cooling and Heat Removal, PWR Portable Equipment Phase 2 -

Deployment Conceptual Design Modifications, Maintain RCS Inventory Control PWR Portable Equipment Phase 2 - Deployment Conceptual Modifications Modifications, Maintain Spent Fuel Pool Cooling PWR Portable Equipment Phase 2 - Deployment Conceptual Design Modifications, and Safety Function Support PWR Portable Equipment Phase 2 -

Deployment Conceptual Design Modifications.

Reason for Change: The FLEX equipment storage building build is complete.

Change: The site storage plan will consist of one robust building "N" and "N+1" FLEX equipment. Adjacent to the robust FLEX Building will be a commercial grade storage building built to ASCE 7-10 standards. The commercial building will hold site equipment as well as support supplies not required by the NEI 12-06 FLEX Strategies. Both buildings will be located outside the protected area north of the main parking lot. In addition, the site strategy will have several strategic temporary hoses and electrical cables staged within robust structures in the plant.

Change 3 Section: In the 6 month updates section 6 Open Items from Overall Integrated Plan and Draft Safety Evaluation Reason for Change: Item 24 in the open item list # 3.2.1.4.A, the EC listed was in error.

Change: EC 393374, Alternate SX Supply to 1/2SX04P Pump Suction FLEX Mod 3, resolves DDAF pump over heating due to SX water recirculation within the SX system by providing an alternate SX supply. 1/2BFSG-2, Alternate AFVV/EFW Suction Source provides operators with the necessary guidance to align the alternate SX supply.

Page 3 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 5

Need for Relief/Relaxation and Basis for the Relief/Relaxation Byron Station, Unit 1 expects to comply with the order implementation date of October 2015.

Byron Unit 2 has received an 18 month extension of the order due to Westinghouse methodology review for the RCP Seal Leakoff and is scheduled to be in compliance May 2016.

NRC letter ADAMS Accession No. ML14260A294: "Accordingly, based upon the authority granted to the Director, Office of Nuclear Reactor Regulation, the requirement of the order for full order implementation for Byron Unit 2 is relaxed until the completion of the Spring 2016 refueling outage to allow the licensee sufficient time to complete the engineering analysis and procedure changes associated with the final, NRC endorsed RCP Seal leakage analytical basis."

6 Open Items from Overall Integrated Plan and Draft Safety Evaluation The following tables provide a summary of the open items documented in the Overall Integrated Plan or the Draft Safety Evaluation (SE) and the status of each item.

01P Section Reference Overall Integrated Plan Open Item Status Key Site assumptions (p.4)

Primary and secondary storage Complete - The FLEX storage locations have not been selected yet; buildings will consist of one once locations are finalized robust building housing "N" implementation strategies and routes and "N+1" FLEX equipment.

will be assessed for hazard impact.

There is also a commercial building housing the non-strategy FLEX equipment.

The robust and commercial buildings are located adjacent to each other outside the protected area, north of the main parking lot.

Primary and alternate deployment routes for FLEX equipment have been identified and are recorded within the site program document Snow removal is addressed as part of the site snow removal plan. Post event snow removal will be accomplished with a snowplow equipped FLEX truck.

The site maximum flood water level is at elevation 870.9 feet resulting from a probable Page 4 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 maximum precipitation (PMP) event. Byron plant grade elevation is at 869.0 feet and does not vary significantly across the site. The FLEX storage building floor will be constructed above the flood level to an elevation of 872 feet. A majority of the travel path elevations are between elevation 869 feet and 870 feet (Ref. 11). Some travel path locations may be covered by a small amount of water.

Since the FLEX pumps and generators are trailer mounted, they should be maintained available when being deployed to different locations at the site.

Debris removal impacts of the travel routes have been evaluated. The primary or alternate travel route will be utilized in the event one path becomes unavailable due to debris. In addition, the site has purchased an F-750 with a snow plow to assist in debris removal.

Extreme hot and cold temperatures should have little impact on the site travel paths.

Liquefaction evaluations of the travel routes have been completed. Conditions do not exist at Byron for soil liquefaction during a severe seismic event and equipment deployment will not be impeded.

Sequence of events (p.5)

The final timeline will be time Complete The timeline from validated once detailed designs are the current design has been completed and procedures are validated.

Page 5 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 developed.

Identify how strategies will be deployed (p.7)

Identification of storage area and creation of the administrative program.

Complete - The robust and commercial buildings will be located adjacent to each other outside the protected area, north of the main parking lot.

Site program document CC-BY-118 has been developed.

Programmatic controls (p.8) Develop an administrative program for FLEX responsibilities, and testing

& maintenance.

Started The corporate and the Site program documents CC-AA -118 and CC-BY-118 have been developed.

Testing and maintenance procedures are being developed based on the EPRI FLEX equipment templates.

National SAFER Response Center plan (p.9)

Development of Byron Station's response plan.

Complete - Byron Station SAFER site response plan (playbook) has been developed.

Key Reactor Parameters (p

multiple)

Identify additional parameters that are needed in order to support key actions identified in the plant procedures/guidance or to indicate imminent or actual core damage.

Complete - All key parameters have been identified and placed in Attachment A.

Deployment Conceptual Design (p. multiple)

Develop the storage structure conceptual design.

Complete - The FLEX storage buildings will consist of one robust building housing "N" and "N+1" FLEX equipment and one commercial building housing site support and FLEX Equipment not required in the NEI 12-06 Strategies.

The robust building will be a 140 feet x 60 feet. The commercial building will be a 60 feet x 60 feet.

Detailed building designs have been issued and construction is complete.

Maintain RCS Inventory A calculation will be required for the timing of the boration and quantity Complete - Calculation BYR13-239/BRW-13-0221-M Page 6 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 Control, Phase 2 (p.23) required.

(Ref. 10) identifies the timing and quantity of boration required. Specifically, boration will need to start prior to 17.6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> into the event and require 15,240 gallons of water injected at 40 gallons per minute.

Maintain Containment, Additional calculations will be Complete - Calculation Phase 1 (p.31) performed to evaluate containment BYR13-235/BRW-13-0217-M response.

(Ref. 12) and BYR14-046/BRW-14-0058 (Ref. 17) evaluate containment response in all modes.

Containment pressure and temperature will reach the FSG setpoint limits in >30 days and 13.7 days, respectively. In addition, containment pressure and temperature will reach design basis pressure and temperature limits in > 30 days.

Maintain Spent Fuel Pool Procedure development for Initial Complete Procedures will Cooling, Phase 1 (p.39)

Spent fuel pool make-up with gravity not be developed for SFP drain from the RWST.

make-up with gravity drain.

The primary method for SFP make-up will be repowering the installed OA refueling water purification pump utilizing the 480V Flex generator connection described in the Safety Functions Support section of Reference 1. The RWST with the installed piping will be used as the suction source.

The discharge will use the existing OA refueling water purification pump discharge piping directly to the SFP. This method is outlined in OBFSG-11, Alternate SFP Makeup Page 7 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 and Cooling.

Maintain Spent Fuel Pool Cooling, Phase 1 (p.39)

Initial calculations were used to determine the fuel pool timelines.

Formal calculations will be performed to validate this information during development of the spent fuel pool cooling strategy detailed design.

Complete - Calculation BYR13-240/BRW-13-0222-M (Ref. 9) determined the spent fuel pool timeline.

With both units at power, time to boil = 10.94 hours0.00109 days <br />0.0261 hours <br />1.554233e-4 weeks <br />3.5767e-5 months <br /> and time to TAF = 90.98 hours0.00113 days <br />0.0272 hours <br />1.62037e-4 weeks <br />3.7289e-5 months <br />. EP procedure set point for requiring makeup is SFP elevation of 420 foot, which should be reached in approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

With one unit in a refueling outage, time to boil = 2.72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> and time to TAF = 43.96 hours0.00111 days <br />0.0267 hours <br />1.587302e-4 weeks <br />3.6528e-5 months <br />.

Maintain Spent Fuel Pool Cooling, Phase 1, (p.39 and p.42)

Evaluation of the spent fuel pool area for steam and condensation will be performed and used to determine if vent path strategy is needed.

Complete - A Spent Fuel Pool (SFP) vent path will be provided by opening the Fuel Handling (FH) building trackway roll-up door per OBFSG-11, Alternate SFP Makeup and Cooling. The site plans to perform required manual actions within the FH building prior to the onset of SFP boiling determined by calculation BYR13-240/BRW-13-0222-M (Ref. 9).

A formal evaluation of the spent fuel pool area for steam and condensation will not be performed.

Safety Functions Support, Phase 2 (p.51)

Habitability conditions will be evaluated and a strategy will be developed to maintain Main Control Room.

Complete - Habitability conditions within the MCR will be maintained with a tool box approach limiting the impact of high temperatures with methods such as supplemental cooling, personnel rotation and/or Page 8 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 availability of fluids.

OBFSG-51, Alternate MCR Ventilation, provides the necessary guidance to establish alternate ventilation within the main control room.

Safety Functions Support, Critical ventilation assets may be Complete - Habitability Phase 2 (p.51) required to support DDAF pumps, station battery rooms, miscellaneous conditions within the Plant will be maintained with a tool box electric equipment rooms, and fuel approach limiting the impact of handling building personnel high temperatures with habitability and/or component methods such as survivability. Specific analyses of these rooms will be performed.

supplemental cooling, personnel rotation and/or availability of fluids.

Component survivability is being evaluated with the following calculations:

Calculation BYR13-234/BRW-13-0216-M, Auxiliary FW Pump Room Temperature Analysis during an ELAP Event, (Ref. 13), shows room temperature is maintained within acceptable limits and supplemental room cooling is not required.

Procedure guidance for setup of alternate cooling was developed to provide additional options to the operators and is controlled by OBFSG-5, Initial Assessment of FLEX Equipment.

Calculation BYR13-237/BRW-13-0219-M, MEER and Battery Room Conditions Following ELAP, (Ref. 14) shows room doors must be opened when the battery Page 9 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 charge is started and forced ventilation is required within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br />.

1/2BFSG-5 / OBFSG-5, Initial Assessment of FLEX Equipment, provides operators with the necessary guidance to establish alternate ventilation.

Calculation BYR13-236/BRW-13-0218-M, Control Room and Auxiliary Electric Equipment Room heat up and Ventilation during an ELAP (Ref. 15) shows the Unit 2 auxiliary electric room portion of the MCR boundary reaching temperature limits first within approximately 5.15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br />. OBFSG-51, Alternate Control Room Ventilation, provides operators with the necessary guidance to establish alternate ventilation.

Interim Safety Evaluation Open Item Byron's ISE Response Status Line Number Item Number Description Answer 1

Open Item 3.2.1.8.A Core Subcriticality-The NRC staff has not endorsed the industry-proposed position paper regarding boron mixing. The licensee has indicated that Byron is planning on following this methodology. Thus, further resolution of this issue will be necessary in the next phase of the audit process.

Complete-Byron will abide by the position expressed by the NRC staff in the letter dated January 8, 2014 regarding the boron mixing issue for PWRs (Adams Accession No. ML13276A183). The NRC letter states that the NRC staff has reviewed the information submitted to date and concluded that use of Page 10 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 the industry approach dated August I 15, 2013, entitled 'Westinghouse Response to NRC Generic Request for Additional Information (RAI) on Boron Mixing in Support of the Pressurized Water Reactor Owners Group (PWROG)," ML13235A135, is acceptable with clarifications listed in the letter.

Reference 10 demonstrates that the Flexible and Diverse Coping Strategies (FLEX) RCS make-up pump will be deployed and capable of injecting into the RCS prior to the time when injection is required including the appropriate time margin to ensure adequate sub-criticality for both the maximum seal leakage and no seal leakage scenarios. The analyses and evaluations supporting the OIP demonstrate that the FLEX RCS make-up pump will be aligned one hour prior to the loop flow rate decreasing below the loop flow rate corresponding to single-phase natural circulation for the assumed highest applicable leakage rate at normal operating pressure and temperature for the reactor coolant pump seals and unidentified reactor coolant system leakage. Therefore, the boron mixing criteria are met.

The current site timeline shows the High pressure FLEX pump will be available for RCS boration within 12 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> of the event initiation which meets the timing requirements outlined in Reference

22.

Confirmatory Items 2

3.1.1.1.A Storage & Protection of FLEX equipment - Confirm final design of Complete - The site FLEX equipment storage structure design Page 11 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 FLEX storage structure conforms to NEI 12-06, Sections 5.3.1, 7.3.1, and 8.3.1 for storage considerations for the hazards applicable to Byron.

is complete and complies with the requirements of 12-06, Sections 5.3.1, 7.3.1, and 8.3.1 storage considerations for the hazards applicable to Byron.

The FLEX storage buildings will consist of one robust building housing "N" and the "N+1" FLEX equipment. There is also a commercial building housing the non-strategy FLEX equipment.

3 3.1.1.3.A Procedural Interface Considerations (Seismic) Confirm procedure for measuring key instruments at containment penetrations using portable instrument, Complete - BFSG-7, Loss of Vital Instrumentation or Control Power has been written. It provides guidance for alternate methods to measure key instruments at appropriate locations within the plant.

4 3.1.1.4.A Off-Site Resources Confirm National SAFER Response Center local staging area and method of transportation to the site in future 6-month update Complete Closed in last 6 month update. (Ref-28) 5 3.1.5.1.A Protection of Equipment (High Temperature) - Confirm FLEX storage structure will maintain FLEX equipment at a temperature range to ensure its likely function when called upon.

Complete - The FLEX storage building's ventilation systems are designed as required by code and to maintain the FLEX equipment in a ready state.

The maximum building temperature will be controlled by forced ventilation.

Temperature information from Byron's UFSAR indicates the site extreme high temperature is a maximum of 102°F.

The FLEX low pressure pump was designed to be able to operate with an outside air temperature of 176°F.

The FLEX medium head and high head pump purchase specification requires a maximum operating air temperature of 110°F.

The FLEX Generator purchase Page 12 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 specification requires a maximum operating air temperature of 122°F.

6 3.1.5.3.A Deployment of Equipment (High Temperature) - Confirm that the effects of high temperature on FLEX equipment have been evaluated in the locations they are intended to operate.

Complete - FLEX equipment has been purchased with appropriate temperature specifications to ensure it will function in the extreme temperature conditions applicable to the site. Temperature information from Byron's UFSAR indicates the site extreme high temperature is a maximum of 102°F.

The FLEX low pressure pump was designed to be able to operate with an outside air temperature of 176°F.

The FLEX medium head and high head pump purchase specification requires a maximum operating air temperature of 110°F.

The FLEX Generator purchase specification requires a maximum operating air temperature of 122°F.

FLEX equipment primary staging locations are located outside of buildings and therefore require no additional cooling.

7 3.2.1.A RCS cooling & RCS inventory control - Specify which analysis performed in WCAP-17601 is being applied to Byron. Additionally, justify the use of that analysis by identifying and evaluating the important parameters and assumptions demonstrating that they are representative of Byron and appropriate for simulating the ELAP transient.

Complete - The primary conditions considered are based on the Westinghouse reference coping cases described in section 5.2.1 of WCAP-17601-P (Ref. 18). The extended loss of alternating current (AC) power (ELAP) simulation parameters matrix provided in Westinghouse correspondence LTR-FSE-14-43 (Ref. 22) outlines the comparison of items for Byron Station.

8 3.2.1.1.A NOTRUMP - Confirm that the use of NOTRUMP in the ELAP analysis is limited to the flow conditions before ref lux condensation initiates. This Complete Exelon has used generic ELAP analysis performed in WCAP 17601-P (Ref. 18) with the NOTRUMP computer code to Page 13 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 includes specifying an acceptable definition for reflux condensation cooli ng.

support the mitigating strategy in its Overall Integrated Plan (01P). The use of NOTRUMP was limited to the thermal-hydraulic conditions before reflux condensation initiates. The initiation of reflux condensation cooling is defined when the one hour centered moving average (CMA) of the flow quality at the top of the SG U-tube bend exceeds 0.1 in any one loop.

The analyses and evaluations supporting the 01P demonstrate that the Flexible and Diverse Coping Strategies (FLEX) reactor coolant system (RCS) make-up pump will be aligned prior to the loop flow rate decreasing below the loop flow rate corresponding to the definition of the onset of reflux cooling. Calculation BYR13-239/BRW-13-0221-M (Ref. 10) demonstrates that the RCS FLEX pump will be deployed and capable of injecting into the RCS prior to the time when injection is required including the appropriate time margin to ensure adequate sub-criticality for both the maximum seal leakage and no seal leakage scenarios. Site timeline shows that the high pressure FLEX pumps are available between 12 and 16 hours1.851852e-4 days <br />0.00444 hours <br />2.645503e-5 weeks <br />6.088e-6 months <br /> following the beyond-design-basis external event (BDBEE) which meets the timing requirements to allow for the necessary Boron mixing.

9 3.2.1.1.B ELAP Analysis - Confirm calculations to verify no nitrogen injection into RCS during depressurization.

Complete - Calculation BYR99-010/BRW-99-0017-1 (Ref. 7) determined the minimum steam generator (SG) pressure to preclude a significant amount of nitrogen from being injected into the RCS from the accumulator is 160 psig. This value was increased to 260 psig by adding an additional 100 psi margin, as recommended by the Westinghouse Owners Group Emergent Procedure Page 14 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 background document.

1/2BCA 0.0 provides direction to stop the RCS depressurization at a SG pressure of 260 psig and isolate the safety injection accumulators.

10 3.2.1.1.0 Confirm analysis for secondary side SG fouling due to the use of abnormal water sources (RWST, well water, SX water)

Complete - Procedural guidance has been developed which follows the industry approach of prioritizing the cleanest to dirtiest water sources.

The first choice of secondary makeup with the DD AF Pp is the Condensate Storage Tank (CST).

If the CST is not available, then by design, the suction will be swapped to the UHS.

At about the 10-hour mark post event, UHS makeup from Well Water, (WW), powered by a FLEX DG will be used.

The National SAFER Response Center will deliver a water purification skid within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

This skid will be installed upon arrival and used to condition the SG cooling water indefinitely.

A quantitative analysis, BYR14-150 Byron Units 1&2 FLEX Steam Generator Degraded Heat Transfer Analysis Through 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> has been completed and is acceptable and provides significant margin in the heat transfer capability of the steam generators. (Ref 26) 11 3.2.1.1.D Complete analysis for length of time prior to depletion of the RWST and determine whether additional boration equipment is needed for Phase 3 coping strategy.

Complete The Site water source for RCS boration and inventory is the two (2) robust RWSTs. The usable volume of 315,000 gallons per RWST should last greater than 7 days with both units in mode 1-4.

An RWST usage calculation, Page 15 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 BYR14-129 / BRW-14-0212-M, RWST Usage During FLEX Scenarios has been completed to determine the need and timing of additional Phase 3 boration equipment. (Ref 27) 12 3.2.1.2.B Reactor Coolant Pump (RCP) Seal Leakage - In some plant designs, the cold legs could experience temperatures as high as 580 °F before cooldown commences. This is beyond the qualification temperature (550°F) of the 0-rings used in the RCP seals. For those Westinghouse designs, a discussion should be provided to justify that (1) the integrity of the associated 0-rings will be maintained at the temperature conditions experienced during the ELAP event, and (2) the seal leakage rate of 21 gpm/seal used in the ELAP is adequate and acceptable.

Complete (1) The Westinghouse letter LTR-RES-13-153, Documentation of 7228C 0-Rings at ELAP Conditions, concludes, with a high level of confidence, that the integrity of the associated 0-Rings will be maintained at the temperature conditions experienced during the ELAP event.

(2) In June 2014, Westinghouse issued PWROG-14015-P, "No.1 Seal Flow Rate for Westinghouse Reactor Coolant Pumps Following Loss of All AC Power." The purpose of this report was to calculate a new number 1 seal leakage rate based on the actual leak-off line layout at Byron Station versus the representative leak-off line layout assumed in WCAP-10541.

The new, lower leakage rates are being utilized in calculation revisions for Containment Pressure, Containment Temperature, and Boration.

13 3.2.1.2.E RCP Seal Leakage Rates - The licensee is requested to provide the manufacturer and model number of the RCP seals and discuss whether or not the RCP and seal combination complies with a seal leakage model described in WCAP-17601.

Complete (Ref-28) 14 3.2.1.3.A Decay Heat-Verify that the Integrated Plan update provides the Started - The Westinghouse Nuclear Steam Supply System Page 16 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 details of the WCAP 17601-P (NSSS) calculations documented in methodology to include the values of WCAP17601-P using the certain key parameters used to NOTRUMP code were performed determine the decay heat levels.

with the ANS 5.1 1979 + 2 sigma Address the adequacy of the values decay heat model and assumed the used.

reactor is initially operating at 100%

power (NOTRUMP reference case core power is 3723 MWt).

Implementation of this model includes fission product decay heat resulting from the fission of U-235, U-238, and Pu-239 and actinide decay heat from U-239 and Np-239. The power fractions are typical values expected for each of the three fissile isotopes through a three region burn-up with an enrichment based on typical fuel cycle feeds that approach 5%. With that, a conversion ratio of 0.65 was used to derive the decay power of the two actinides U-239 and Np-239. Fission product neutron capture is treated per the ANS standard. The decay heat calculation utilizes a power history of three 540-day cycles separated by two 20-day outages that bounds initial condition 3.2.1.2 (1) of the Nuclear Energy Institute (NEI) document NEI 12-06, Section 3.2.1.2 (with a minimum assumption from NEI 12-06 that the reactor has been operated at 100%

power for at least 100 days prior to event initiation). Therefore, the decay heat curve assumed in the Westinghouse calculations in WCAP 17601-P is representative of Byron Units 1 and 2. The primary-side transient profile assumed in the reactor coolant system (RCS) inventory control and long-term sub-criticality calculations for Modes 1 through 4 with steam generators available is based on Page 17 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 the Westinghouse reference coping case of WCAP-17601-P and plant specific parameters such as reactor coolant system nominal temperature(s), pressures(s), and volumes, and accumulator cover gas pressures. These calculations do not, however, include any decay heat model and rely on the case runs cited from WCAP-17601-P regarding decay heat related phenomenon.

15 3.2.1.4.A Initial Values for Key Plant Parameters and Assumptions-Confirm WCAP-17601-P analyses are bounding for Byron for strategy response or verify plant-specific analyses if more restrictive limits are used due to more restrictive plant specific limits, Complete - The primary system conditions considered are based on the Westinghouse reference coping cases described in Section 5.2.1 of WCAP-17601-P (Ref. 18). The extended loss of alternating current (AC) power (ELAP) simulation parameters matrix provided in Westinghouse Correspondence LTR-FSE-14-43 (Ref. 22) outlines the comparison of items for Byron Station.

16 3.2.1.42 Initial Values for Key Plant Parameters and Assumptions-Confirm calculations to validate 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> run time limit on DDAF pump batteries and DDAF room temp for pump operation and human occupancy. Also, confirm site phase 2 staffing study confirms the required time can be met for refilling diesel day tank.

Complete - Calculation BYR13-238/BRW-13-220-E (Ref. 19) confirms the pump batteries can operate for > 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> following ELAP event.

Calculation BYR13-234/BRW 0216-M (Ref. 13) shows room temperature limit for equipment survivability is not challenged.

Habitability conditions will be maintained with a tool box approach limiting the impact of high temperatures with methods such as supplemental cooling, personnel rotation and/or availability of fluids.

OBFSG-5, Initial Assessment and FLEX Equipment Staging, provides the necessary actions to install temporary fans to provide cooling to the DDAF pump room.

Page 18 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 The Phase 2 staffing study was completed in April 2014. Results were submitted to the NRC by letter RS-14-129 dated May 29, 2014.

17 3.2.1.5.A Monitoring Instruments and Control-Confirm additional parameters evaluated for use in plant procedures/guidance or to indicate imminent or actual core damage.

Complete (Ref-28) 18 3.2.1.6.A Sequence of Events - Confirm that the final timeline has been time validated after detailed designs are completed and procedures are developed. The results may be provided in a future 6-month update.

Complete - The final timeline was validated as the time sensitive actions, listed in Attachment 1A, went through the validation process.

19 3.2.1.6.B Sequence of Events - Confirm analysis to validate Phase 2 pump capacities.

Complete - Hydraulic calculation BYR13-144/BRW-13-0160-M (Ref.

20), FLEX Pump Sizing and Hydraulic Analysis, evaluates the FLEX high pressure, medium pressure and low pressure pump capacities. The calculations validate the capability of the Phase 2 pumps for their intended FLEX purpose.

20 3.2.1.9.A Use of portable pumps - Confirm final design of strategies meets "use of portable pumps" guideline in NEI 12-06 Section 3.2.2 Guideline 13.

Complete - Station FLEX strategies utilize 1/2BCA 0.0, loss of all AC, as the controlling document to identify and implement the supporting BFSG Series procedures.

The low pressure FLEX pump connection and line-up is controlled by OBFSG-5, Initial Plant Assessment and FLEX Equipment Staging.

The medium pressure pump connection and line-up is controlled by 1/2BFSG-3, Alternate Low Pressure Feedwater.

The high pressure pump connection and line-up is controlled by 1/2BFSG-1, Long Term RCS Page 19 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 Inventory Control, and 1/2BFSG-8, Alternate RCS Boration.

21 3.2.2.A SFP cooling -Verify procedure for SFP makeup via gravity drain; confirm verification of timeline for performing the strategy; and confirm evaluation of SFP area for steam and condensation affects.

Complete - The Spent fuel pool make-up via gravity drain from the RWST procedure guidance is not being developed due to its limited make-up flow. The primary means for SFP make-up utilizes the installed OA Refueling Water Purification Pump with FLEX AC power. OBFSG-11, Alternate SFP Make-up and Cooling, provides operators with the necessary guidance to execute the task.

The SFP environment has the potential to communicate with the Aux Building via the FHB supply ducting, because the FHB Supply dampers fail open on a loss of AC.

It is reasonable to assume this flow path will be isolated by fire damper OVA413Y. The fire damper will close when its fusible link melts shortly after reaching a set point of 165°F. Due to this damper arrangement and lack of motive force, minimal FHB atmosphere should be dispersed into the Aux Building.

OBFSG-5, Initial Assessment and FLEX Equipment Staging, or OBFSG-11, Alternate SFP make-up and Cooling, establish a Spent Fuel Pool Vent path by opening the SFP trackway roll-up door.

The site does have manual actions within the spent fuel pool building to setup temporary hose for pool make-up. The site plans to perform these manual actions prior to the onset of SFP boiling. OBFSG-5, Initial Assessment and FLEX Equipment Staging and OBFSG-11, Alternate SFP make-up and Page 20 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 Cooling, provide the necessary guidance to execute the task.

All local operator actions are completed prior to SFP boiling. The final time line has been validated.

The only equipment in the FHB post event that are required are the newly installed SFPI instruments which are designed to operate in this environment.

22 3.2.3.A Containment - Confirm containment reanalysis supports no Phase 1, 2, and 3 mitigation strategies are required because containment pressure and temperature are maintained within acceptable limits.

Complete Calculation BYR13-235/BRW-13-0217-M (Ref. 12)

Containment Pressure and Temperature Response during an ELAP Event, confirms the response supports Phases 1, 2, and 3 mitigation strategies. Containment pressure and temperature will reach the FSG setpoint limits in >30 days and 13.7 days, respectively.

In addition, containment pressure and temperature will reach design basis pressure and temperature limits in > 30 days.

23 3.2.3.B Containment - Confirm evaluation performed for the need to monitor containment temperature.

Complete Calculation BYR13-235/BRW-13-0217-M (Ref. 12) shows Containment pressure and temperature will reach the FSG set point limits in >30 days and 13.7 days, respectively. In addition, containment pressure and temperature will reach design basis pressure and temperature limits in

> 30 days. Even with these long timeframes, containment temperature has been added to the key parameter list to provide operators with additional tools.

Monitoring of containment temperature can be performed on an intermittent basis and will be controlled by emergency procedures and 1/2BFSG-7, Loss of Vital Instrument or Control Page 21 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 Power.

24 3.2.4.1.A Equipment cooling - Confirm modification has been performed to prevent DDAF pump from overheating due to cooling water recirculation flow paths within the SX system cycling and overheating the pump within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />.

Complete - EC 393374, Alternate SX Supply to 1/2SX04P Pump Suction FLEX Mod 3, resolves DDAF pump over heating due to SX water recirculation within the SX system by providing an alternate SX supply. 1/2BFSG-2, Alternate AFW/EFW Suction Source provides operators with the necessary guidance to align the alternate SX supply.

25 3.2.4.2.A Ventilation - Equipment Cooling -

Review licensee's evaluation of loss of ventilation effects on equipment in various rooms (DDAF pump room, battery rooms, control room, miscellaneous electrical equipment rooms)

Complete - Calculation BYR13-234/BRW-13-0216-M, Auxiliary FW Pump Room Temperature Analysis during an ELAP Event, (Ref. 13),

shows room temperature is maintained within acceptable limits and supplemental room cooling is not required. Procedure guidance for the setup of alternate cooling was developed to provide additional options to the operators and is controlled by OBFSG-5, Initial Assessment of FLEX Equipment Calculation BYR13-237/BRW 0219-M, MEER and Battery Room Conditions Following ELAP (Ref.

14), shows battery room can reach 2% hydrogen concentration within 2.52 hours6.018519e-4 days <br />0.0144 hours <br />8.597884e-5 weeks <br />1.9786e-5 months <br /> of re-energizing the battery charger.

Hydrogen generation begins when the battery chargers are re-energized.

When power is re-established to the battery charger, power is also returned to the battery room vent fan. Operation of the battery room vent fan will prevent hydrogen generation from becoming a concern. 1/2BFSG-5, Initial Assessment and FLEX Equipment Staging, provides operators with Page 22 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 the necessary guidance to establish forced ventilation within the battery room. Additionally, this calculation shows the MEER room will require forced ventilation to preserve component availability within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> of re-energizing the battery changers. 1/2BFSG-5 /

OBFSG-5, Initial Assessment of FLEX Equipment, provides operators with the necessary guidance to establish alternate ventilation.

Calculation BYR13-236/BRW 0218-M, Control Room and Auxiliary Electric Equipment Room heat up and Ventilation during an ELAP (Ref. 15) shows the Unit 2 Auxiliary Electric Equipment Room portion of the MCR boundary reaching temperature limits first within approximately 5.15 hours1.736111e-4 days <br />0.00417 hours <br />2.480159e-5 weeks <br />5.7075e-6 months <br />.

OBFSG-51, Alternate Control Room Ventilation, provides operators with the necessary guidance to establish alternate ventilation.

26 3.2.4.2.B A discussion is needed on the extreme high/low temperatures effects of the battery's capability to perform its function for the duration of the ELAP event and hydrogen gas ventilation during recharging batteries during Phase 2 and 3.

Complete - Calculation BYR13-237/BRW-13-0219-M, MEER and Battery Room Conditions Following ELAP (Ref. 14), shows battery room can reach 2% hydrogen concentration within 2.52 hours6.018519e-4 days <br />0.0144 hours <br />8.597884e-5 weeks <br />1.9786e-5 months <br /> of re-energizing the battery charger.

Hydrogen generation begins when the battery chargers are re-energized.

When power is re-established to the battery charger, power is also returned to the battery room vent fan. Operation of the battery room vent fan will prevent hydrogen generation from becoming a concern. 1/2BFSG-5, Initial Assessment and FLEX Equipment Staging, provides Page 23 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 operators with the necessary guidance to establish forced ventilation within the battery room.

Calculation BYR13-237/BRW 0219-M (Ref. 14) assumes a battery room maximum temperature of 138F and a minimum temperature of 60F during an ELAP event. The temperature effects on the battery capacity were incorporated into this calculation.

27 3.2.4.3.A Heat Tracing - Confirm that potential adverse impacts from a loss of heat tracing and normal heating on any equipment credited for ELAP mitigation are adequately addressed. In particular, ensure an RCS inventory and source of borated water is available for a BDBEE associated with extreme cold, ice, and snow.

Complete - The site FLEX strategy has been evaluated for potential freezing due to loss of heat trace or other heat sources. Susceptible equipment includes the RWST, temporary hoses and pumps deployed outside. A calculation, to show the effects of freezing on this equipment is complete, BYR14-130/BRW-14-0211-M, Evaluation of Tank and Hose Freezing during an ELAP, (Ref.25). The FLEX temporary hoses, routed outside, will be protected from freezing by maintaining positive flow or by draining when not in use. Additional sections of FLEX hose are also available as a replacement in the event a section of the hose freezes.

28 3.2.4.4.A Communications - Confirm that upgrades to the site's communications systems have been completed.

Started - Communications upgrade conceptual design is complete.

For the 1st - 2nd refuel

t ou age, (B2R18), the site will have 3 Iridium Satellite phones available for the SM/SED in the MCR area.

Additional handheld radios for use on talk-around mode with batteries are staged in the robust FLEX building. The site will have Sound Powered phones and cords in lockers in the plant with cables as Page 24 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 well as Bull Horns for help with notifications.

In addition, for the 2nd 2nd Refuel outage, (B1 R20), the site will complete the NARS Upgrade satellite communications system.

Detail design will be communicated in a future 6 month update.

29 3.2.4.6.A Personnel Habitability - Review licensee's evaluation of loss of ventilation effects on personnel habitability and accessibility.

Complete (Ref-28) 30 3.2.4.7.A Water Sources - Justify the time at which SG dryout will occur.

Complete (Ref-28) 31 3.2.4.8.A Electrical Power Sources /Isolation and interactions-confirm class lE equipment is protected from faults in portable/FLEX equipment and multiple sources do not attempt to power electrical buses.

Complete - 1/2BFSG-5, Initial Assessment and FLEX Equipment Staging, provides electrical bus isolation and ensures multiple sources are not simultaneously connected to buses.

The portable FLEX DG circuit breakers are sized to provide over-current protection downstream of the circuit breakers.

32 3.2.4.9.A Portable Equipment Fuel - Confirm that complete analysis of fuel usage requirements has been developed after the specific FLEX equipment is identified and the fuel usage is determined. A discussion is needed on maintaining the quality of fuel stored in the tanks for extended periods of time Complete - The Units 1 and 2 "B" tanks contain 100,000 gallons of fuel. It is reasonable to assume the site fuel supply will last until roads can be re-opened and local tanks can replenish the supply. The site has an additional 100,000 gallons contained in the "A" train tanks, but it is not directly available to the Diesel fuel oil transfer pumps. The site also has 125,000 gallon and 50,000 gallon storage tanks that are not robust but would be used if available. An analysis has been completed to show that the refueling capability of our F-750 truck is sufficient to ensure all of the FLEX diesel driven equipment can be kept re-fueled until Page 25 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 additional capabilities can be brought to the site.

33 3.2.4.10.A Load reduction to conserve DC power-Confirm sizing calculations for FLEX generators and details of load shedding.

Complete - EC393367, Electrical FLEX Connections to Unit 2 Safety Related Buses (Bus 232x),

contains FLEX DG sizing calculations.

DC load shedding will be performed in accordance with BFSG-4, ELAP DC Load Shed/Management. Load shedding should start at approximately 35 minutes after the start of an ELAP event and complete within 65 minutes.

BYR14-060/BRW-14-0080-E (Ref.

8) demonstrates the Division 2 DC batteries will last at least 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> with the performance of appropriate load shedding.

7 Potential Draft Safety Evaluation Impacts There are no potential impacts to the Draft Safety Evaluation identified at this time.

8 References The following references support the updates to the Overall Integrated Plan described in this enclosure.

1. Byron Station, Units 1 and 2, "Overall Integrated Plan in Response to 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),"

dated February 28, 2013 (RS-13-017).

2. NRC Order Number EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events,"

dated March 12, 2012.

3. NEI 12-06 Rev. 0, Diverse and Flexible Coping Strategies (FLEX) Implementation Guide, dated August 2012.
4. Byron Station's First Six Month Status Report for the Implementation of FLEX, dated August 28, 2013.

Page 26 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015

5. Byron Station's Second Six Month Status Report for the Implementation of FLEX, dated February 28, 2014.
6. Byron Station, Units 1 and 2 Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Order EA-12-049 (Mitigating Strategies) (TAC NOS. MF0895 AND MF0896), dated December 17, 2013.
7. BYR99-010/BRW-99-0017-1 Rev. 2, Documentation of the Basis of the Emergency Operating Procedures (EOP) Setpoints, dated June 2014.
8. BYR14-060/BRW-14-0080-E Rev. 0, Unit 1(2) 125 VDC Battery FLEX Coping Calculation Common Calc Beyond Design Basis, dated May 2014.
9. BYR13-240/BRW-13-0222-M Rev. 0, Spent Fuel Pool Boil Off Analysis during an ELAP Event, dated March 2014.
10. BYR13-239/BRW-13-0221-M Rev. 0, RCS Boration Analysis during an ELAP Event, dated June 2014.
11. Exelon Structural Drawing S-183 Rev. AF, Roadway Plan Plant and Construction Laydown Area, dated May 2014.
12. BYR13-235/BRW-13-0217-M Rev. 0, Containment Pressure and Temperature Response during an ELAP Event, dated June 2014.
13. BYR13-234/BRW-13-0216-M Rev. 0, Auxiliary FW Pump Room Temperature Analysis during an ELAP Event, dated March 2014.
14. BYR13-237/BRW-13-0219-M Rev. 0, MEER and Battery Room Conditions Following ELAP, dated June 2014.
15. BYR13-236/BRW-13-0218-M Rev. 0, Control Room and Auxiliary Electric Equipment Room heat up and Ventilation during an ELAP, dated June 2014.
16. BYR13-026/BRW-13-0031-M Rev. 0, Transient Analysis of SX System Following Loss of A-C Power, dated August 2014.
17. BYR14-046/BRW-14-0058-M Rev. 0, Containment Environment Following an Extended Loss of AC Power During Shutdown, dated June 2014.
18. WCAP 17601-P.Rev. 1, Reactor Coolant System Response to the Extended Loss of AC Power Event for Westinghouse, Combustion Engineering and Babcock & Wilcox NSSS Designs, dated January 2013.
19. BYR13-238/BRW-13-220-E Rev. 0, DDAF Pump Battery Duty Cycle and Sizing for a BDBEE, dated January 2014.
20. BYR13-144/BRW-13-0160-M Rev. 0, FLEX Pump Sizing and Hydraulic Analysis, dated April 2014.
21. Letter to Mr. Jack Stringfellow titled "Boron Mixing Endorsement Letter in Regards to Mitigation Strategies Order EA-12-049," January 8, 2014. (Agency wide Documents Access and Management System (ADAMS) Accession Number ML13276A183).

Page 27 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015

22. Westinghouse Correspondence LTR-FSE-14-43, Revision O-A, "Exelon Generation Company, LLC Mitigation Strategies Order (EA-12-049) Design ELAP Simulation Parameters," July 16, 2014.
23. BYR14-119 UHS Rev 0, Volume Analysis during an ELAP Event dated July 2014.
24. Letter to David Flahive, of Westinghouse, titled "Exelon Generation Company, LLC Mitigation Strategies Order (EA-12-049) Open and Confirmatory Item Responses,"

Letter LTR-FSE-14-61 Rev.0-A dated July 17, 2014.

25. BYR14-130/BRW-14-0211-M Rev. 0, Evaluation of Tank and Hose Freezing during an ELAP, dated Aug 2014.
26. BYR14-150 Byron Units 1&2 FLEX Steam Generator Degraded Heat Transfer Analysis Through 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />, dated Nov 2014.
27. BYR14-129 / BRW-14-0212-M, RWST Usage During FLEX Scenarios, dated October 2014.
28. Byron Station's Third Six Month Status Report for the Implementation of FLEX, dated August 28, 2014.

Page 28 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 Attachment A Key Parameters Essential Instrumentation Safety Function SG Pressure:

PI-515, PI-516, PI-525, PI-535, PI-545 and PI-546 RCS pressure boundary and pressure control SG Level:

NR - LI-517, LI-519, LI-527, LI-537, LI-547 and LI-549 WR - LI-502 and LI-503 RCS pressure boundary and pressure control RCS Temperature:

Cold Leg - TI-413B, TI-423B, TI-433B and TI-443B RCS heat removal RCS temperature: Hot leg - TI-413A, TI-423A, TI-433A and TI-443A RCS heat removal Core Exit Thermocouple (CET) Temperature TI-1T002 RCS heat removal RCS Pressure: WR - PI-403 RCS pressure boundary and pressure control Pressurizer level: LI-460 RCS inventory Vessel Level Indicating System (RVLIS) LI-RCO20 RCS inventory Containment integrity Containment Pressure: PI-PC005 Containment Temperature: TE-VP030, TE-VP031, TE-VP032, and TE-VP033.

Containment integrity Spent Fuel Pool Level: OLI-FC001B and OLI-FC002B.

SFP inventory RWST Level Channel LT-931 RCS inventory Post Accident Neutron Monitor NI-NR006 A/B Reactor core subcriticality DC Bus Voltage _EI-DC002 Battery c9:24city AFW Flow: FI-AF012A, FI-AF014A, Fl-AF016A and F1-AF018A RCS heat removal RCS heat removal RCS heat removal RCS inventory AFW Suction Pressure PI-AF055 CST level: ILI CD051A Accumulator Level: LI951, LI953, LI955, and LI 957 Core Exit Thermocouple TI-1T002, Reactor Vessel Level Indicating System LI-RCO20, Post Accident Neutron Monitor NI-NR006 A/B and Spent Fuel Pool Level OLI-FC001B and OLI-FC002B will be re-energized per the site strategy.

Page 29 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 Attachment B Phase 3 Equipment PWR Portable Equipment Phase 3 Use and (potential /flexibility) diverse uses Performance Criteria Notes Note:

The National SAFER Response Center NRC equipment is being procured at the time of this submittal.

The equipment listed is a generic list provided by the National SAFER Response Center and even though we may not requi.e this equipment in our plan it will be available and could be utilized in the phase 3 time period.

List portable equipment Core Containment SFP Instrumentation Accessibility Medium Voltage Diesel Generator X

X X

X X

1 MW output at 4160 Vac. three phase Note 1 Backup equipment Low Voltage Diesel Generator X

X X

X X

1100 kW output at 480 Vac, three phase Note 2 Backup equipment High Pressure Injection Pumps X

2000 psi shutoff head, 60 gpm capacity Backup equipment SG/RPV Makeup Pump X

500 psi shutoff head. 500 gpm max flow Backup equipment Low Pressure /

Medium Flow Pump X

X X

300 psi shutoff head, 2500 gpm max flow Backup equipment Low Pressure /

High Flow X

X 150 psi shutoff head, 5000 gpm max flow Backup equipment Page 30 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 PWR Portable Equipment Phase 3 Use and (potential / flexibilio) diverse uses Performance Criteria Notes Note:

The National SAFER Response Center NRC equipment is being procured at the time of this submittal.

The equipment listed is a generic list provided by the National SAFER Response Center and even though we may not require this equipment in our plan it will be available and could be utilized in the phase 3 time period.

List portable equipment Core Containment SFP Instrumentation Accessibility Cable /

Electrical X

X X

Various as determined by ARE VA document # 51-9199717-005 Backup equipment Hose /

Mechanical Connections X

X X

Various as determined by AREVA document # 51-9199717-005 Backup equipment Lighting Towers X

40.000 lumens Backup equipment Diesel Fuel Transfer 500 gallon air-lift container Backup equipment Diesel Fuel Transfer Tank 264 gallon tank, with mounted AC/DC pumps Backup equipment Portable Fuel Transfer Pump 60 gpm after filtration Backup equipment Electrical Distribution System 4160 V. 250 MVA, 1200 A Backup equipment Page 31 of 36

Byron Station, Units 1 and 2 - Fourth Six Month Status Report for the Implementation of FLEX February 27, 2015 PWR Portable Equipment Phase 3 Use and (potential / flexibility) diverse uses Performance Criteria Notes Note:

The National SAFER Response Center equipment is being procured at the time of this submittal. The equipment listed is a generic list provided by the National SAFER Response Center and even though we may not require this equipment in our plan it will be available and could be utilized in the phase 3 time period.

List portable equipment Core Containment SFP Instrumentation Accessibility Mobile Boration X

X Each mobile boration unit consists of three (3) stand-alone trailers containing:

  • Main tank, mixers, pumps and control panel on one stand-alone trailer
  • Generator and heater on one stand-alone trailer
  • A main generator on one stand-alone trailer Provide Borated Water Source Water Purification X

X The water treatment equipment shall have an output flow capacity of 250 gpm (demineralized water)

Provide Quality Water Source Note 1: 1 MW is the individual generator output, and 2 MW is the total standard output to be supplied by the Phase 3 MV generators to satisfy identified load demands. The total output is created by connection of several smaller generators in parallel.

Note 2: The 1100 kW unit is derated to 1000 kW.

Page 32 of 36

Byron Station, Units 1 Remarks /

Applicability The times to complete actions in the Events Timeline are based on operating judgment, the conceptual designs, and the current supporting analyses.

NA Unit 1 and Unit 2

@100% power NA _BCA 0.0, Loss of All AC Power, action.

Y 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> _BCA 0.0, Loss of All AC Power, action. Reference WCAP 17601-P reference.

Y* 15

BCA 0.0, Loss of minutes

All AC Power, action. Reference WCAP 17601-P and operator judgment Time Constraint Y/N Action Event Starts, BDBEE occurs, Unit 1 and Unit 2 reactors 0

automatically trip and all rods are inserted.

Loss of off-site power (LOOP) affecting both units occurs 1 min Emergency Operating Procedures, (EOPs) and Station Black Out, (SBO), Procedures are entered.

5-50 mins

Verify DDAF Pp is operating properly.

5 - 15 mins

MCR closes C & D S/G PORVs to conserve inventory.

Elapsed Time c

o E U

4-,

  • CC

N C'n

1.

Page 33 of 36

Remarks /

Applicability

_BCA 0.0, Loss of All AC Power, action.

_BCA 0.0, Loss of All AC Power, attachment B for ELAP Reference BRW 0080-E Rev 0, Unit 1(2) 125 VDC Battery FLEX Coping Calculation Common Calc Beyond Design Basis, dated May 2014.

1

, g

c

  • =c,

i r:4 6 0 X c-) bn 1:)

1)
1) z

in

o 73 73 t.,-,

00

.-.,-j

4-,

0-,

>-1

r4S'

f24 o

= L) C-) CO CO cv 0

0

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C o,-,

a)

  • ^' ,

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0

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  • 7 0

ct

cn 1<

cc: 14 124 <C 1-4 0-.

cn Time Constraint Y/N Z

4 s-,

0

..=

co CI)

,r,

a)

E cn 1-,

=

0

,. =

N Action Attempt starting Emergency D/G's ELAP condition recognized and ELAP Procedures are entered.

Connect FLEX 480V AC generators to ESF bus _32X and verify they are supplying power to Div 2 - 125V DC battery chargers Operators dispatched to perform DC Bus Load Shed SX Short Cycle Cooling EC is aligned to cool the B AF Pp within 2 hour2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> after pump start.

Elapsed Time C,, 0

.g C

cn,L 30 mins 30 rnins to 6 hrs 35 mins to 65 mins 9

55 mins to 90 mins C

0 o

E

.4-.

h oo Page 34 of 36

Remarks!

Applicability

_BCA 0.0, Loss of All AC Power, action. Reference BRW-13-0221-M Rev 0, RCS Boration Analysis during an ELAP Event, dated June 2014.

Operator Judgment Reference BRW 0221-M Rev 0, RCS Boration Analysis during an ELAP Event, dated June 2014

=

° -3 I.) 0 > 09 a)

..s, C<

g 7-7<'

cn

(4

c..) =

'S m 0 -='-- 0 0 Time Constraint Y/N o o

,.=

N 1

NA In "

tri I

if, 0

=

Action Start depressurization of S/Gs to 260 psig at approximately 75"F/hr cooldown with SG PORV local/manual operation. SG feed is controlled with Local/Manual operation of AFW flow control valves.

SI Accumulator borated water begins to inject into the RCS Maintain SG pressure 260 psig and RCS temperature between 420F 410F with SG PORV operation.

Maintain SG level.

13 3 5 hrs Set up and establish ventilation in AEER and MCR Elapsed Time co) 7-.

-= r 2.25 hrs 3.5 hrs C OE L..)

4,

.4

Page 35 of 36

I 1/2BFSG -10 action c

-5 x *1-;' a 7;

"c

u CA c LLI ci..) _<

rt)

0

c

  • C 0

'0- 6.0 LI. 6.

4 E

li

el.)

r,..*

0

r,..)

C)

Li,

1..)

75

j.1., L4

ce)

cl -c

- cq

`' 0'0 Reference WCAP 17601-P and Westinghouse Letter LTR-FSE-14-61, Rev. O-A Dated July 2014.

1/2BFSG-5action.

OBFSG-llaction.

Reference BRW 0222-M Rev 0, Spent Fuel Pool Boil Off Analysis during an ELAP Event, dated April 2014.

National SAFER Response Center Guide.

End of analytical simulation.

Isolate SI Accumulators

NA Y 17 hours1.967593e-4 days <br />0.00472 hours <br />2.810847e-5 weeks <br />6.4685e-6 months <br />

  • zr*

crN ci,

cn o

>".=

s c o

>" =

-tt Z Z

Z Z

Deploy FLEX DG to SX tower switchgear room and establish power to one of the ESF Busses 131Z/132Z for power to a Well Water, (WW), Pump and establish make up flow to the UHS.

Deploy all hoses and connections in FHB for alternate SFP Fill strategy before FHB becomes uninhabitable from SFP Boiling.

Stage and connect Phase 2 high pressure FLEX Pumps and ensure they are available to supply borated make-up to the RCS and inject prior to entering Reflux Cooling.

Stage and connect Phase 2 med head FLEX Pumps and ensure they are available to supply make-up to the SG's.

Initiate SFP Make up via OA FC Purification pump as required for level and temperature control.

National SAFER Response Center resources begin arriving on site.

21 24 - 72 hrs

Continue to maintain critical functions of Core Cooling (via DDAF), RCS Inventory Control (via FLEX pump injection to RCS) and SFP Cooling (via FLEX pump injection to SFP). Utilize initial National SAFER Response Center equipment and resources.

5 7 hrs 6 9 hrs cr.

4...

,..c o

.0 12 16 hrs cn

..= o el

.0 24 hrs 24 hrs

  • 71- - -

44' s

..0 oc -

c.-J. -

0 N

Page 36 of 36

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