RS-14-008, 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-12-049)
| ML14059A425 | |
| Person / Time | |
|---|---|
| Site: | Byron  |
| Issue date: | 02/28/2014 |
| From: | Kaegi G Exelon Generation Co |
| To: | Document Control Desk, Office of Nuclear Reactor Regulation |
| References | |
| EA-12-049, RS-14-008 | |
| Download: ML14059A425 (34) | |
Text
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)i Exelon Order No. EA-12-049 RS-14-008 February 28, 2014 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:
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-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
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. 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
U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 February 28, 2014 Page 2 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 EGC 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 EGC 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. Reference 6 provides the first six-month status report pursuant to Section IV, Condition C.2, of Reference 1 for Byron Station. The purpose of this letter is to provide the second 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 7.
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 28th day of February 2014.
Respectfully submitted,
~iT,Z¥ Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC
Enclosure:
- 1. Byron Station, Units 1 and 2 Second Six-Month Status Report for the Irnplementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events
u.s. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 February 28, 2014 Page 3 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. Peter Bamford, NRRlDPR/MSD/MSPB, NRC Illinois Emergency Management Agency - Division of Nuclear Safety
Enclosure Byron Station, Units 1 and 2 Second 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 (30 pages)
Byron Station, Units 1 and 2 Second 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 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 None.
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 Activity Status Revised Target Completion Date Completion Date
.. Submit 60 Day Status Report Complete Submit Overall Integrated Complete Implementation Plan Contract with R RC Complete Submit 6 Month Updates:
Aug 2013 Update 1 Complete Feb 2014 Update 2 Complete with this submittal Aug 2014 Update 3 Not Started Feb 2015 Update 4 Not Started Aug 2015 Update 5 Not Started Page 1 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 Unit 1 Unit 2 Modification Development Aug Dec
- Phase 1 modifications 2014 2013 Aug Dec
- Phase 2 modifications Detailed Designs 2014 2013 Started Aug Dec
- Phase 3 modifications Not Started 2014 2013 Unit 1 Unit 2 Modification Implementation Sept Oct
- Phase 1 modifications 2015 2014 Sept Oct
- Phase 2 modifications Not Started 2015 2014 Sept Oct
- Phase 3 modifications Not Started 2015 2014 Procedure Development Oct 2014
- Strategy procedures Started Apr 2014
- Validate Procedures (NEI Started 12-06, Sect. 11.4.3)
Oct 2014
- Maintenance procedures Not Started Jun 2014 Staffing analysis !\Jot Started Oct 2014 Storage Plan and construction Started Oct 2014 FLEX equipment acquisition Started Oct 2014 Training completion Started Aug 2014 Regional Response Center Started Operational Sept 2015 Unit 1 Implementation date Not Started Oct 2014 Unit 2 Implementation date Not Started Page 2 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 4 Changes to Compliance Method Change 1 Section: Multiple Sections Reason for Change: For consistency throughout this project we have chosen to utilize the calculations of the WCAP-17601-P for our reference calculations.
Reason for Change: With engineering review and judgment the values from the WCAP are bounding.
Change 2 Section: General Integrated Plan Elements PWR - Provide a sequence of events and identify any time constraint required for success including the technical basis for the time constraint.
Reason for Change: Modification design details were refined as parts of the standardized modification design process and manual actions have been added and verified to accomplish these tasks.
Change:
- 1. Added new step to close the 2 S/G PORVs that have battery backup when it is verified that there is no Auxiliary Feedwater. This will conserve S/G inventory and provide symmetric cooling as required in the W CAP-17601-P.
- 2. Added new step to shed DC Loads as recommended by WCAP-17601-P along with procedure reference 1/2BFSG-4, ELAP DC Load Shed/Management.
- 3. Added new step to align the AF pump SX cooling water FLEX supply within two (2) hours of pump start to prevent overheating 'from the short cycle of the cooling water along with the procedure reference of 1/2BFSG-2, Alternate AFW/EFW Suction Source.
- 4. Added new step to deploy all hoses and connections in the FHB for alternate SFP fill and RCS inventory/boration strategies, before the FHB becomes uninhabitable due to SFP boiling. This is expected to occur within six (6) hours of the event initiation and will be governed by procedures OBwFSG-5, Initial Assessment and FLEX Equipment Staging Unit 0, and OBwFSG-11, Atternate SFP Make-Up and Cooling.
Change 3 Section: Maintain Core Cooling & Heat Removal- PWR Installed Equipment Phase 1 and Maintain RCS Inventory Control- PWR Installed Equipment Phase 1 Reason for Change: Site alignment with Nuclear Energy Institute (I\1EI) position paper dated September 18, 2013, entitled "Position Paper: Shutdown/ Refueling Modes" Change: Change last paragraph to the following:
Cold Shutdown and Refueling: When in Cold Shutdown and Refueling, many variables exist which impact the ability to cool the core. In the event of an ELAP during these Modes, installed plant systems cannot be relied upon to cool the core, thus transition to Phase 2 will be required sooner. All efforts will be made to expeditiously provide core cooling and minimize heat-up and Page 3 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 repressurization. Exelon has a program in place (Ref. 3) to determine the time to boil for all conditions during shutdown periods.
To accommodate the activities of vessel disassembly and refueling, water levels in the reactor vessel and the reactor cavity are often changed. The most limiting condition is the case in which the reactor head is removed and water level in the vessel is at or below the reactor vessel flange. If an ELAP/LUHS occurs during this condition then (depending on the time after shutdown) boiling in the core may occur quite rapidly. Deploying and implementation of portable FLEX pumps to supply injection flow must commence immediately from the time of the event.
This should be plausible because more personnel are on site during outages to provide the necessary resources. Strategies for makeup water include deploying a FLEX pump to take suction from the RWST and lor UHS as described in the Phase 2 Core Cooling section.
Guidance will be provided to ensure that sufficient area is available for deployment and that haul paths remain accessible without interference from outage equipment during refueling outages.
Change 4 Section: Maintain Core Cooling & Heat Removal- PWR Installed Equipment Phase 1 -Identify Modifications Reason for Change: Modification design details have been refined as parts of the standardized modification design process Change: (replace section with the following)
The following gaps have been identified that prevent operation of the DDAF pump:
- 1. DDAF pump suction flow path is not available due to CST unavailability and failure of the CST isolation valve to close and the SX suction valve to open on loss of AC power.
- 2. DDAF batteries are drained due to repetitive engine starts with automatic reset of low-low suction pressure trip
- 3. DDAF pump overheating due to cooling water recirculation flow paths within SX system cycling and overheating the pump within two (2) hours.
Gap 1 will be resolved with manual operator actions. Operators will be procedurally directed to open the SX suction valves (1/2AF006 and 1/2AF017) and close the CST isolation valves (1/2AF002) prior to starting the DDAF pump.
Gap 2 will be resolved by modifying the DDAF pump logic to lock-out the pump after unsuccessful starting attempts prior to draining the battery. This lockout will be manually reset after the DDAF pump suction is realigned.
Gap 3 will be resolved by modifying the DDAF pump SX cooling water flow path. The modification consists of installing a piping tee on the discharge of both Unit 1 and Unit 2 "B" SX pump discharge lines on the 330' elevation in the AB. These tees will be connected by a header and routed vertically through the AB to the 383' elevation. On the 383' elevation, the line will tee into two lines feeding the 1/2 DDAF pump SX booster pump. This new line will be isolated during normal operation. In the event of an ELAP, this new line will be aligned and the normal SX cooling supply to the DDAF pump SX booster pump will be isolated.
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Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 Change 5 Section: Maintain Core Cooling & Heat Removal- PWR Portable Equipment Phase 1,2 and 3-Key Reactor parameters and Maintain RCS Inventory Control - PWR Portable Equipment Phase 1, 2 and 3 - Key Reactor parameters.
Reason for Change: FLEX strategy has been refined and draft site FSG procedures have been developed.
Change: RWST level channel _L T-931_has been identified as a required instrument for the FLEX strategy.
In addition, Core Exit Thermocouple (CET) temperature _TI-IT002, Reactor Vessel Level indicating System (RVLlS) _Ll-RC020, and Post Accident Neutron monitor _NI-NR006 AlB will be re-energized per the site strategy.
Change 6 Section: Maintain Core Cooling & Heat Removal- PWR Portable Equipment Phase 2 - Identify Modifications Reason for Change: Modification design details have been refined as parts of the standardized modification design process Change: (replace section with the following)
The following modifications will be installed to support FLEX pump water injection into the SGs Primary: A pipe flange connection will be attached to the Band C Auxiliary Feedwater (AF) SG injection lines at the existing test flanges within the 377' Main Steam Safety Valve (MSSV) rooms. The pipe flanges will be connected to a header and routed vertically to the 401' elevation in the BIC MSSV room. The header will be terminated with a standard FLEX connection inside the robust MSSV room above the 401' elevation. This will allow a FLEX pump to provide cooling water to the BIC SGs Alternate: This modification is identical to the primary except it is within the AID MSSV room. It will allow a FLEX pump to supply cooling water to the AID SGs.
Note: Both the BlC and AID headers in the 377' MSSV rooms will have flanges allowing a temporary hose to connect the headers and allow one FLEX pump to feed all four (4) SG's. This temporary hose will be stored within the robust Main Steam Tunnel for easy deployment.
FLEX pump suction: A tee will be installed on the A SI pump suction line, (in the B SI Pump Room). A header will be routed from the tee to the robust RWST tunnel area and terminated with a standard FLEX connection. Temporary hoses will be routed through the RWST tunnel hatch to connect this line to the FLEX pump suction located outside.
Note: The SG cooling water source is prioritized 'from cleanest to dirtiest. The priority is the CST (not robust) and then the UHS (River water). The Well Water system will be repowered in Phase 2 and supplied to the UHS and the medium pressure diesel FLEX pump. The RWST (Boration source) will also be available, if needed, to the medium pressure FLEX diesel pumps until the WW to FLEX pump hoses are in place. Additionally, a water filtration unit will be requested from the RRC and installed to provide purification of the UHS water source as staffing permits.
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Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 Change 7 Section: Maintain Core Cooling and Heat Removal, - PWR Portable Equipment Phase 2-Deployment Conceptual Design - Strategy, Maintain RCS Inventory Control- PWR Portable Equipment Phase 2 - Deployment Conceptual Modifications - Strategy, Maintain Spent Fuel Pool Cooling - PWR Portable Equipment Phase 2 - Deployment Conceptual Design - Strategy, and Safety Function Support - PWR Portable Equipment Phase 2 - Deployment Conceptual Design - Strategy Reason for Change: The site storage building will consist of one robust building housing UN" FLEX equipment and a commercial building housing "+1" FLEX equipment. The site strategy will have several strategic temporary hoses and electrical cables staged within robust structures in the plant Change: (replace section with the following)
The required FLEX equipment needed for Core Cooling, RCS Inventory Control, Spent Fuel Pool Cooling and Safety Function Support will be stored in a FLEX building and transported to a pre-identified staging location. Hoses and electrical cables to support the site coping strategy will be stored within the FLEX building or staged in the plant. The equipment deployment strategy will be validated and reported in a future six (6) month update.
Change 8 Section: Maintain Core Cooling & Heat Removal- PWR Portable Equipment Phase 3, Maintain RCS Inventory Control- PWR Portable Equipment Phase 3, Maintain Spent Fuel Pool Cooling
- PWR Portable Equipment Phase 3, and Safety Functions Support - PWR Portable Equipment Phase 3.
Reason for Change: Site FLEX strategy has been refined as parts of the standardized modification design process and through detailed reviews.
Change: (replace section with the following)
Phase 3 equipment for Byron includes backup portable pumps and generators. The portable pumps will be capable of providing the necessary flow and pressure as outlined in Phase 2 response for Core Cooling & Heat Removal, RCS Inventory Control and Spent Fuel Pool Cooling. The portable generators will be capable of providing the necessary 480 volt power requirements as outlined in Phase 2 response for Safety Functions Support.
In addition, a water purification skid and a boration skid will be requested from the RRC to support Phase 3 strategy Change 9 Section: Maintain Core Cooling & Heat Removal - PWR Portable Equipment Phase 3 -
Strategy, Maintain RCS Inventory Control - PWR Portable Equipment Phase 3 - Strategy.
Maintain Spent Fuel Pool Cooling - PWR Portable Equipment Phase 3 - Strategy. and Safety Functions Support - PWR Portable Equipment Phase 3 - Strategy.
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Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 Reason for Change: RRC will provide operating instructions for the equipment delivered to the site.
Change: (replace section with the following)
Equipment will be delivered from the RRC to the staging area. From there, the equipment will be transported to the site and hooked up by both RRC and plant personnel per the playbook.
Equipment will then be operated per industry developed operating instructions.
Change 10 Section: Maintain RCS Inventory Control - PWR Portable Equipment Phase 2 Reason for Change: Draft calculations have been prepared which show the RCS accumulators inject a portion of their concentrated boric acid inventory maintaining the reactor subcritical.
Change: (replace section with the following)
Phase 2 RCS inventory control and boration will be achieved within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> via a portable pump. The pump suction will be from the RWST. The discharge will be into the CV/SI pump discharge line downstream of the CV/SI pump. A calculation is in progress to validate the time frame and any change to this will be provided in a future six (6) month update.
Electrical power to support the FLEX strategy is described in the Safety Function Support section.
Change 11 Section: Maintain RCS Inventory Control- PWR Portable Equipment Phase 2 - Identify modifications Reason for Change: Modification design details have been re'fined as parts of the standardized modification design process Change: (replace section with the following)
The following FLEX modifications will be installed to support inventory and boration of the RCS:
FLEX pump discharge: The "B" CV pump discharge header, downstream of check valve
_CV8481 B, will be modified with a tee and a standard FLEX connection (Alternate). The flow path goes through a normally closed MOV _S18801 AlB which can be manually opened or the "B" train MOV can be electrically opened after the FLEX DG energizes the associated Div 2 ESF Bus.
FLEX pump suction: The "B" SI pump discharge header, downstream of _S18921 B, will be modified with a tee. A header will be routed from a tee to the RWST tunnel and terminated with a standard FLEX connection (Primary). Deployment of this flow path will be contingent on primary pressure conditions less than 1750 psig due to the SI discharge header relief valves.
FLEX pump Suction: A tee will be installed on the "A" SI pump suction line, (In the "B" SI Pp Room). A header will be routed from the tee to the robust RWST tunnel area and terminated Page 7 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 with a standard FLEX connection. Temporary hoses will be routed through the RWST tunnel hatch to connect this line to the FLEX pump suction located outside.
Note: The RCS Inventory water source priority is the respective Unit's RWST.
A Boration skid will be requested from the RRC to provide a borated make-up source as needed.
Change 12 Section: Maintain Spent Fuel Pool Cooling - PWR Installed Equipment Phase 1 Reason for Change: The spent fuel pool area vent path strategy has been developed.
Change: Replace - Evaluation of the spent fuel pool area for steam and condensation has not yet been performed. The results of this evaluation and the vent path strategy, if needed, will be provided in a future six (6) month update.
With the following: A Spent Fuel Pool Vent path will be provided by opening the Fuel Handling Building track way roll-up door. The site does have manual actions within the Fuel Handling building. The actions include setting up SFP make-up temporary hoses and the RCS inventory control alternate injection path hoses. The site plans to perform these manual actions prior to the onset of SFP boiling. The actions will be directed by the FSGs being developed.
The SFP environment has the potential to communicate with the Aux Building via the FHB supply ducting, due to the FHB Supply dampers failing 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 AB.
Change 13 Section: Maintain Spent Fuel Pool Cooling - PWR Portable Equipment Phase 1, 2 and 3 - Key SFP parameters.
Reason for Change: SFP design has identified the EPNs for the SFP level instrumentation.
Change: Replace SFP Level: (component # TBD) with Spent Fuel pool level: OLl-FC001 Band OLl-FC002B Change 14 Section: Maintain Spent Fuel Pool Cooling - PWR Installed Equipment Phase 2 Reason for Change: The spent fuel pool cooling and area vent path strategy has been developed Change: (replace section with the following)
The SFP cooling will be achieved with one of the following methods:
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Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 The primary method will be repowering the installed OFC03PA, OA refueling water purification pump, utilizing the 480V Flex generator connection described in the Safety Functions Support section. 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.
The secondary method will be achieved with a portable FLEX diesel pump and temporary hoses routed to the SFP via the FHB track way. The FLEX pump suction will be from Well Water, UHS or RWST.
A Spent Fuel Pool Vent path will be provided by opening the FHB track way roll-up door. The site does have manual actions within the spent fuel pool building to setup pool make-up temporary hoses and route the RCS inventory alternate connection hoses. The site plans to perform these manual actions prior to the onset of SFP boiling. The actions will be directed by the FSGs being developed.
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 165F. Due to this damper arrangement and lack of motive force, minimal FHB atmosphere should be dispersed in to the AB Change 15 Section: Maintain Spent Fuel Pool Cooling - PWR Portable Equipment Phase 2 - Identify modifications Reason for Change: The Spent fuel pool make-up strategy has changed. 1\10 modifications will be required for Phase 2 Spent Fuel Pool Cooling.
Change: (replace section with the following)
The primary make-up strategy will use the installed OFC03PA, OA refueling water purification pump, and associated piping as directed by OBFSG-11, Alternate SFP Make Up and Cooling.
The pump will be repowered as part of the site plan to re-energize safety related 480V buses with a FLEX generator. The pump's suction source is the RWST. Its discharge piping provides flow directly to the SFP. Make-up to the RWST can be performed by completing EDMG-1, Extensive Damage Mitigation Guideline Attachment 10.
The alternate make-up strategy will be via temporary hoses routed from a FLEX pump to a spray nozzle located in the vicinity of the SFP. The temporary hose / spray nozzle required to be routed within the FHB will be stored in that building and deployed prior to the onset of SFP boiling.
FHB vent path will be established by opening the FHB track way rollup door.
Change 16 Section: Safety Support Function - PWR Portable Equipment Phase 1,2 and 3 - Key Parameters.
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Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 Reason for Change: FLEX strategy has been refined and draft site FSG procedures have been developed.
Change: DC Bus Voltage _EI-DC002, has been identified as a required instrument for the FLEX strategy.
Change 17 Section: Safety Function Support - PWR Portable Equipment Phase 2 Reason for Change: Site FLEX strategy has been refined through industry reviews and site challenges.
Change: (replace section with the following)
A portable diesel generator will provide power to one (1) division of the 480V ESF busses.
Repowering at this level will permit the recovery of one division of station battery chargers, DDAFP battery chargers, MCCs powering critical equipment such as Diesel fuel oil transfer pumps, and other ESF equipment beneficial in mitigating the event.
Exelon Generation Company, LLC (Exelon) intends to maintain Operational command and control within the Main Control Room (MCR). Habitability conditions within the MCR and other areas of the plant 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.
The fuel handling building habitability should be maintained until the SFP begins to boil. The site does have manual actions within the Fuel Handling Building. The actions include setting up SFP make-up temporary hoses and the RCS inventory control alternate injection path hoses.
The site plans to perform these manual actions prior to the onset of SFP boiling. The actions will be directed by the FSGs being developed.
Critical ventilation assets may be required to support DDAF pumps, the OA refueling water purification pump, the station battery rooms and the miscellaneous electric equipment room component survivability. Specific analyses of these rooms are open items and will be addressed as part of the detailed engineering design phase. Closure of these items will be documented in a future six (6) month update.
Change 18 Section: Safety Function Support - PWR Portable Equipment Phase 2 - Indentify Modifications Reason for Change: Modification design details have been refined as parts of the standardized modification desig n process.
Change:
The primary FLEX connection will be installed adjacent to MCC 132X and MCC 232X. An existing spare breaker within these MCCs will be modified such that its load side feed is connected to a new disconnect switch and patch panel. Temporary cables will be routed from the patch panel to the associated Unit's FLEX generator at the 401' TB track way entrance.
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Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 Once the MCC is energized, appropriate breakers will be closed to provide power to the safety related batteries.
The Alternate strategy is to provide a connection via the existing Site DC crosstie. In the event either Unit's primary FLEX strategy is unable to be implemented, DC busses 112 and 212 will be cross-tied to provide power to the site B train safety related batteries. In addition, the other required 480V critical loads will be powered up via a patch panel and TPU in the Auxiliary Building which is powered from either unit FLEX DG.
The discharge of the existing diesel fuel oil transfer pumps is being modified with a tee and isolation valve within the B main diesel generator rooms. This connection, along with temporary hoses and reenergizing the diesel fuel oil transfer pumps will provide a fuel source for the FLEX equipment.
Change 19 Section: PWR Portable Equipment Phase 2 Reason for Change: Modification design details have been refined as parts of the standardized modification design process.
Change: The Four (4) 480 VAC Generators will be 350 KW instead of the listed 500 KW.
Change 20 Section: Phase 3 Response Equipment/Commodities - Heavy Equipment Reason for Change: Site strategy details have been refined as a result of strategy reviews Change:
The F750 Truck has been purchased with a snow plow for debris removal. The F-750 will also be used for equipment deployment and FLEX equipment refueling.
In addition Byron will be acquiring 2 F-250, or equivalent, trucks with snow plows. They will tow the first needed Phase 2 equipment: the Flex DG for each unit.
All three trucks will then be utilized to transport additional equipment as required by the event and the Phase 2 plans.
Change 21 Section: Attachment 1A, Sequence of Events time line.
Reason for Change: Modification design details were refined as parts of the standardized modification design process and manual actions have been added and verified to accomplish these tasks.
Change: Added new steps and rearranged to reorder based on strategy updates, (see attachment 1A at end of this submittal).
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Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014
- 1. Added new step 4 to close UPS powered SG PORVs to conserve inventory until _B AF Pp can be started.
Performed to align with WCAP-17601-P and in accordance with new 1/2BFSG-4.
- 3. Added new step 9 for the short cycle cooling mod for the _B AF Pumps.
- 4. Added new step 13 for layout of alternate strategy hoses for RCS make-up and SFP make-up in the FHB before it is not habitable.
- 5. Added new step 14 for SI Accumulator isolation.
- 6. Added new step 15 for new primary strategy for SFP make-up.
- 7. Changed time on step 16 to 12-14 hrs.
- 8. Added new step 17 for well water pump power.
- 9. Changed time on step 18 to 16-18 hrs to ensure boron is available when required.
Change 22 Section: Attachment 3 Conceptual Sketches Reason for Change: Modification design details were refined as part of the standardized modification design process resulting in changes to the mechanical conceptual sketches.
Change: Current mechanical conceptual sketches are attached to this document. See .
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Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 5 Need for Relief/Relaxation and Basis for the Relief/Relaxation Byron Station, Units 1 and 2 expects to comply with the order implementation date and no relief/relaxation is required at this time.
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.
Section Reference Overall Integrated Plan Open Item Status Key Site assumptions Primary and secondary storage Started (p.3) locations have not been selected yet; once locations are finalized implementation strategies and routes will be assessed for hazard impact.
Sequence of events The final timeline will be time validated Not Started (p.S) once detailed designs are completed and procedures are developed.
Identify how Identification of storage area and Started strategies will be creation of the administrative program.
deployed (p.6)
Programmatic Develop an administrative program for Started controls (p.?) FLEX responsibilities, and testing &
maintenance.
Regional Response Development of Byron Station's Started Center plan (p.8) playbook.
Key Reactor Identify additional parameters that are Started Parameters (p. needed in order to support key actions multiple) identified in the plant procedures/guidance or to indicate imminent or actual core damage.
Deployment Develop the storage structure Started Conceptual Design conceptual design.
(p. multiple)
Maintain RCS A calculation will be required for the Started Inventory Control, timing of the boration and quantity Phase 2 (p.22) required.
Maintain Additional calculations will be Started Containment, Phase performed to evaluate containment 1 (p.30) response.
Page 13 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 Maintain Spent Fuel Procedure development for Initial Complete - Procedures will Pool Cooling, Phase Spent fuel pool make-up with gravity not be developed for SFP 1 (p.37) 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 I utilizing the 480V FLEX generator connection described in the Safety Functions Support section.
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.
Maintain Spent Fuel Initial calculations were used to Started Pool Cooling, Phase determine the fuel pool timelines.
1 (p.37) Formal calculations will be performed I to validate this information during development of the spent fuel pool cooling strategy detailed design.
Maintain Spent Fuel Evaluation of the spent fuel pool area Complete.
Pool Cooling, Phase for steam and condensation will be A Spent Fuel Pool Vent path 1, (p.37 and pAO) performed and used to determine if will be provided by opening vent path strategy is needed.
the Fuel Handling building track way rOil-up door. The site plans to perform required manual actions within the FH building prior to the onset of SFP boiling. A formal calculation will not be performed.
Safety Functions Habitability conditions will be evaluated Complete. Habitability I Support, Phase 2 and a strategy will be developed to conditions within the MCR wilt *
(pA8) maintain Main Control Room. be maintained with a tool box approach limiting the impact of high temperatures with methods such as supplemental cooling, personnel rotation and/or I Page 14 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28,2014 availability of fluids.
I Safety Functions Critical ventilation assets may be Started - Habitability Support, Phase 2 required to support DDAF pumps, conditions within the Plant will I
(p.48) station battery rooms, miscellaneous be maintained with a tool box electric equipment rooms, and fuel approach limiting the impact handling building personnel habitability of high temperatures with and/or component survivability. methods such as I Specific analyses of these rooms will supplemental cooling, be performed. personnel rotation and/or /
I I
availability of fluids.
I Analysis is in progress to ensure component survivability post event.
Interim Safety Evaluation Open Item Status Byron's ISE Response Line Item Description Answer Number Number 1 Open Item Core Subcriticality- The NRC Started- Byron will abide by the
. 3.2.1.8.A staff has not endorsed the position expressed by the NRC industry-proposed position paper staff in the letter dated January 8, regarding boron mixing. The ' 2014 regarding the boron mixing licensee has indicated that Byron issue for PWRs (Adams Accession is planning on following this No. ML13276A183). The NRC i methodology. Thus, further letter states that the NRC staff has resolution of this issue will be reviewed the information submitted necessary in the next phase of to date and concluded that use of the audit process. the industry approach dated August 15,2013, entitled 'Westinghouse Response to NRC Generic Request for Additional Information (RAI) on I Boron Mixing in Support of the Pressurized Water Reactor Owners Group (PWROG)," ML13235A135, is acceptable with clarifications I listed in the letter.
I The analyses and evaluations I supporting the 01 P will demonstrate I I that the FLEX RCS makeup pump
' is being implemented one-hour I prior to the loop flow rate I decreasin below the 100 flow rate Page 15 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 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 Confirmatory Items 2 3.1.1.1.A Storage & Protection of FLEX Started - The site FLEX equipment equipment - Confirm final design storage structure is under of FLEX storage structure development and will comply with conforms to NEI 12-06, Sections the requirements of 12-06, Sections 5.3.1, 7.3.1! and 8.3.1 for 5.3.1, 7.3.1, and 8.3.1 for storage storage considerations for the considerations for the hazards hazards applicable to Byron. applicable to Byron.
The FLEX storage buildings will consist of one robust building housing uN" FLEX equipment and one commercial building housing the "+ 1" FLEX equipment.
3 3.1.1.3.A Procedural Interface Started - 1/2 BFSG-7, Loss of Vital Considerations (Seismic)-- Instrument or Control Power, is Confirm procedure for measuring being developed. It will provide key instruments at containment guidance to measure key penetrations using portable instruments at appropriate locations instrument. within the plant.
4 3.1.1.4.A Off-Site Resources -- Confirm Started.
RRC local staging area and method of transportation to the site in future 6-month update.
5 3.1.5.1.A Protection of Equipment (High Started - The FLEX storage Temperature) - Confirm FLEX buildings ventilation systems will be storage structure will maintain designed as required by code and FLEX equipment at a to maintain the FLEX equipment in temperature range to ensure its a ready state. The minimum likely function when called upon. temperature will be maintained at or above 32°F and the maximum building temperature will be maintained by natural air ventilation utilizing vents. Temperature information from Byron's UFSAR indicates the site extreme Page 16 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 temperatures range is from a maximum of 102°F to a minimum of
-20°F.
6 3.1.5.3.A Deployment of Equipment (High Started - Temperature information Temperature) - Confirm that the from Byron's UFSAR indicates the effects of high temperature on extreme Temperatures up to a FLEX equipment have been maximum of 102°F.
evaluated in the locations they FLEX equipment is being ordered are intended to operate.
with temperature limits to ensure it will function in the extreme temperature conditions applicable to the site.
7 3.2.1.A RCS cooling & RCS inventory Started - The WCAP-17601-P will control - Specify which analysis be evaluated to ensure that it is performed in W CAP-17601 is bounding for Byron.
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.
8 3.2.1.1.A NOTRUMP - Confirm that the Started - Byron will use generic use of NOTRUMP in the ELAP ELAP analyses performed with the analysis is limited to the flow NOTRUMP computer code to conditions before reflux support the mitigating strategy in its condensation initiates. This Overall Integrated Plan (OIP). The includes specifying an use of NOTRUMP was limited to acceptable definition for reflux the thermal-hydraulic conditions condensation cooling. before reflux condensation initiates.
The initiation of reflux condensation cooling is defined when the one hour centered moving average (CMA) of the now quality at the top of the SG U-tube bend exceeds 0.1 in anyone loop.
9 3.2.1.1.B ELAP Analysis - ConIirm Started - Engineering calculations calculations to verify no nitrogen are being performed to verify RCS injection into RCS during Pressure will be held above the depressurization. point of accumulator N2 injection until the accumulator isolation Page 17 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 valves LS18808s) are closed.
10 3.2.1.1.C Confirm analysis for secondary Complete - A water analysis is not side SG fouling due to the use of planned for Byron Station.
abnormal water sources (RWST, Procedural guidance will be well water, SX water) developed utilizing the cleanest to dirtiest water.
The SG cooling water source is prioritized from cleanest to dirtiest.
The priority is the CST (not robust) and then the UHS (River water).
The Well Water system will be repowered in Phase 2 and supplied to the UHS and the medium pressure diesel FLEX pump. The I, RWST (boration source) will also be available, if needed, to the medium pressure FLEX diesel pumps until the WW to FLEX pump hoses are in place. Additionally, a water filtration unit will be requested from the RRC and installed to provide purification of the UHS water source as staffing permits.
11 3.2.1.1.0 Complete analysis for length of ! Started. The RWST volume of I
time prior to depletion of the ' 450,000 gallons with maximum RWST and determine whether output of 470 gpm will last -14 additional boration equipment is hours once this flow is initiated. I needed for Phase 3 coping The 470 gpm flow rate will not be strategy. initiated at the beginning of the event. The RCS inventory and I
Boration of 40 gpm will not be required for - 20 hours2.314815e-4 days <br />0.00556 hours <br />3.306878e-5 weeks <br />7.61e-6 months <br />. The 130 I
gpm required for SFP make-up will not be required for - 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. The SG make-up of 300 gpm should not be required.
The site has 2 RWSTs that can be
, used for FLEX on either unit.
I I A boration skid will be requested II from the RRC.
12 3.2.1.2.B Reactor Coolant Pump (RCP) Started Page 18 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 Seal Leakage - In some plant designs, the cold legs could I
experience temperatures as high as 580°F before cooldown commences. This is beyond the qualification temperature (550°F) of the O-rings used in the RCP seals. For those Westinghouse designs, a discussion should be provided to justify that (1) the integrity of the associated O-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.
13 3.2.1.2.E RCP Seal Leakage Rates - The Complete - The Byron RCPs are licensee is requested to provide model 93A. This aligns with the the manufacturer and model seal leakage model listed in WCAP number of the RCP seals and 17601-P analysis as shown in discuss whether or not the RCP Table 5.3.1.7-1 and seal combination complies with a seal leakage model I
I described in WCAP-17601.
14 3.2.1.3.A Decay Heat- Verify that the Started - From the WCAP-17601-P Integrated Plan update provides page 4-13 and the NEI 12-06 the details of the WCAP 17601-P section 3.2.1.2 the methodology of methodology to include the decay heat values of ANS 5.1-values of certain key parameters 1979+2 sigma is being evaluated to used to determine the decay ensure it bounds the NEI 12-06 heat levels. Address the 3.2.1.2 assumption of 100 days at adequacy of the values used. i 100% power.
I 15 3.2.1.4.A Initial Values for Key Plant Started - The WCAP-17601-P will Parameters and Assumptions- be evaluated to ensure that it is
! Confirm WCAP-17601-P bounding for Byron.
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 Page 19 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 limits.
16 3.2.1.4.B Initial Values for Key Plant Started - The Phase 2 staffing Parameters and Assumptions- study, scheduled for April 2014, Confirm calculations to validate 8 results will be provided in a future hours run time limit on DDAF six (6) month update.
pump batteries and DDAF room temp for pump operation and human occupancy. Also, confirm Calculations for AF Battery run time site phase 2 staffing study are in progress and will be provided confirms the required time can in a future six (6) month update.
be met for refilling diesel day Room temperatures will be tank. controlled under the tool box approach limiting the impact of high temperatures with methods such as supplemental cooling, personnel rotation and/or availability of fluids.
17 3.2.1.S.A Monitoring Instruments and Started - The required Control- Confirm additional instrumentation listed in the Byron parameters evaluated for use in Station OIP is consistent with NEI plant procedures/guidance or to 12-06. The RWST level channel indicate imminent or actual core LT-931 has been identified as a damage. required instrument for the FLEX strategy. In addition, Core Exit Thermocouple (CETC) temperature TI-IT002, Reactor Vessel Level indicating System (RVLlS) LI-RC020, and Post Accident Neutron monitor NI-NR006 AlB will be re-energized, as staffing permits.
18 3.2.1.6.A Sequence of Events - Confirm Started - The final time line will be that the final time line has been validated after the detailed design time validated after detailed is completed and will be provided in designs are completed and a future six (6) month update.
procedures are developed. The results may be provided in a future six (6) month update.
19 3.2.1.6.B Sequence of Events - Confirm Started - Analysis for the Phase 2 analysis to validate Phase 2 pump capacity is in progress and pump capacities. will be provided in a future six (6) month update.
20 3.2.1.9.A Use of portable pumps - Confirm Started - The current design of our final design of strategies meets FLEX strategies utilizing the "use of portable pumps" procedures being written, BCA 0.0 Page 20 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 guideline in NEI 12-06 Section along with the BFSG Series will 3.2.2 Guideline 13. ensure that the plant operators will have the guidance and direction to adequately cooldown and depressurize the plant to allow the cooling flows from our specified Phase 2 equipment and will meet the requirements of NEI 12-06 section 3.2.2 guideline 13.
21 3.2.2.A SFP cooling -Verify procedure Started -The Spent fuel pool make-for SFP makeup via gravity up via gravity drain from the RWST drain; confirm verification of is not being developed.
timeline for performing the The final time line will be validated strategy; and confirm evaluation after the detailed deSign is of SFP area for steam and completed and will be provided in a I condensation affects.
future six (6) month update. I The SFP environment has the potential to communicate with the Auxiliary Building via the FHB supply ducting, because the FHB Supply dampers fail open on a loss of AC. It is reasonable to assume I this flow path will be isolated by fire damper OV A413Y. The fire damper I will close when its fusible linkmelts shortly after reaching a set point of I 165F. Due to this damper arrangement and lack of motive force, minimal FHB atmosphere should be dispersed in to the AB A Spent Fuel Pool Vent path will be provided by opening the SFP track way roll-up door. The site does I
have manual actions within the spent fuel pool building to setup pool make-up temporary hoses.
The site plans to perform these I manual actions prior to the onset of SFP boiling. The actions will be directed by the FSGs being developed.
22 3.2.3.A Containment - Confirm IStarted - Containment calculations containment reanalysis supports are in progress and the results will !
Page 21 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 no Phase 1, 2, and 3 mitigation be provided in a future six (6) strategies are required because month update.
containment pressure and temperature are maintained within acceptable limits.
23 ,3.2.3.B Containment - Confirm Started - Containment calculations evaluation performed for the are in progress and the results will need to monitor containment be provided in a future six (6) temperature. month update.
24 3.2.4.1.A Equipment cooling - Confirm Started - This modification is in modification has been performed detailed design phase and to prevent DDAF pump from procedures are being drafted to overheating due to cooling water align the flowpath within the recirculation flow paths within the required two (2) hours of the pump SX system cycling and start.
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 />.
25 3.2.4.2.A Ventilation - Equipment Cooling - Started - Calculations are in Review licensee's evaluation of progress for the various rooms loss of ventilation effects on listed. The results will be provided equipment in various rooms in a future six (6) month update.
(DDAF pump room, battery rooms, control room, miscellaneous electrical equipment rooms) 26 3.2.4.2.B A discussion is needed on the Started - Calculations are in extreme high/low temperatures progress and the results will be effects of the battery's capability provided in a future six (6) month to perform its function for the update.
duration of the ELAP event and hydrogen gas ventilation during recharging batteries during Phase 2 and 3.
27 3.2.4.3.A Heat Tracing - Confirm that Started - The study of adverse potential adverse impacts from a effects of cold weather conditions loss of heat tracing and normal on available RCS inventory sources heating on any equipment will be performed and credited for ELAP mitigation are communicated in a future six (6) adequately addressed. In month update.
particular, ensure an RCS Additionally, RRC boration inventory and source of borated equipment will be provided with a water is available for a BDBEE method to ensure availability of associated with extreme cold, Page 22 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 r ice, and snow. borated water.
28 3.2.4.4.A Communications - Confirm that Started upgrades to the site's communications systems have been completed.
29 3.2.4.6.A Personnel Habitability - Review Complete - Habitability conditions licensee's evaluation of loss of within the MCR and other areas of ventilation effects on personnel the plant will be maintained with a habitability and accessibility. I tool box approach limiting the impact of high temperatures with methods such as supplemental cooling, personnel rotation and/or I availability of fluids.
I 30 3.2.4.7.A Water Sources - Justify the time ' Complete - Based on WCAP- \
at which SG dryout will occur. 17601-P Table 5.4.1.1-1 Case 2A I I
I S/G dryout would occur at 3,670 I seconds, (61.16 minutes).
31 3.2.4.8.A Electrical Power Sources I I Started - Electrical isolation will be Isolation and interactions- provided as part of the FLEX confirm class 1 E equipment is procedural guidance. For example; protected from faults in feed breakers 1425X and 2425X for portable/FLEX equipment and 480V bus 132X and 232X will be multiple sources do not attempt opened prior to re-energizing these to power electrical buses. 480 volt buses with the FLEX
! Generator.
32 3.2.4.9.A Portable Equipment Fuel - Started - The Unit 1 and Unit 2 "B" Confirm that complete analysis tanks contain 100,000 gallons of of fuel usage requirements has fuel. It is reasonable to assume the I been developed after the specific site fuel supply will last until roads FLEX equipment is identified and can be reopened and local tanks the fuel usage is determined. A can replenish the supply. The site discussion is needed on has an additional 100,000 gallons maintaining the quality of fuel contained in the "A" train tanks, but stored in the tanks for extended it is not available to the Diesel fuel periods of time. oil transfer pumps without additional modifications. The site also has 125,000 gallons and 50,000 gallons storage tanks that are not robust and must be assumed unavailable, but would be used if available.
The complete analysis of fuel usage requirements will be Page 23 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 developed after the specific FLEX equipment is identified and fuel use is determined.
Replacement fuel will be ordered with the same fuel quality standards of current fuel.
33 3.2.4.10.A Load reduction to conserve dc Started - AC Power Diesel sizing power- Confirm sizing calculations for the FLEX DG are calculations for FLEX generators being performed in the electrical and details of load shedding. modification package to reenergize the required AC Bus. DC Load shedding will be performed in accordance with BFSG-4, ELAP DC Load Shed/Management, being developed.
Page 24 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 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-13-018).
- 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.
- 5. 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. MF0893 AND MF0894), dated December 17, 2013.
9 Attachments 1A Sequence of Events Timeline 3 Updated Mechanical One Line Diagrams Page 25 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28,2014 Attachment lA Sequence of Events Timeline Time Remarks!
Elapsed Constraint Applicability Action item Time Action YIN 1 The times to complete actions in the Events Timeline are based on operating judgment, the conceptual designs, and the current supporting analyses. The final timeline will be time validated once detailed designs are completed, procedures are developed, and the results will be provided in a future six (6) month update.
1 0 Event Starts, BDBEE occurs, Unit 1 and Unit 2 reactors NA Plant @100%
automatically trip and all rods are inserted. power Loss of off-site power (LOOP) affecting both units occurs 2 1 min Emergency Operating Procedures, (EOPs) and Station NA _BCA 0.0, Loss of Black Out, (SBO), Procedures are entered. All AC Power, action.
3 5-50 mins Verify DDAF Pp is operating properly. 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. 1I2BFSG-2 4 5-15 mins MCR closes C & D S/G PORV s to conserve inventory. Y -15 _BCA 0.0, Loss of The C& D S/G PORV s are still energized and would mins All AC Power, control in auto to maintain S/G Pressure. action, As referenced in WCAP-17601-P and Operator judgment.
5 10-30 mins Attempt starting Emergency DIG's NA _BCA 0.0, Loss of All AC Power, action.
6 30 mins ELAP condition recognized and ELAP Procedures are NA _BCA 0.0, Loss of entered. All AC Power, attachment B for ELAP 7 30 mins to Connect FLEX 480V AC generators to ESF bus _ 32X Y 3.6
Reference:
EC-and verify they are supplying power to Div 2 - 125V DC EVAL # 391872 1 Instructions: Provide justification if No or NA is selected in the remark column If yes include technical basis discussion as requires by NE112-06 section 3.2.1.7 Page 26 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 3.6 hrs battery chargers hrs Battery Copi ng Time For The 125V DC ESF Battery Banks, dated February 8, 2013 8 35-75 mins Operators dispatched to perform DC Bus Load Shed Y - 3.6 Required by hrs WCAP-17601-P and directed by 1I2BFSG-4 9 55 mins to SX Short Cycle Cooling EC is aligned to cool the B AF Y -2 hour _BCA 0.0, Loss of 90 mins Pp within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> after pump start. All AC Power, action & 1I2BFSG-2 10 1.5 hrs Start depressurization of S/Gs to 300 psia at Y-2hrs _BCA 0.0, Loss of approximately 75°F/hr cooldown with SG PORV All AC Power, local/manual operation. SG feed is controlled with action. As Local/Manual operation of AFW flow control valves. referenced in WCAP-17601-P 11 2.25 hrs SI Accumulator borated water begins to inject into the NA Operator Judgment RCS 12 4 hrs Maintain RCS 300 psia I-420°F with SG PORV N Operator Judgment operation. WCAP-17601-P section 5.2.1 page 5-4 Maintain SG level.
13 4-6 hrs Deploy all hoses and connections in FHB for Alternate Y-6 hrs Directed from i strategies for SFP Fill and RCS Inventory make up via OBFSG-5 and the B CV Pp discharge connections before FHB OBFSG-ll I
becomes uninhabitable from SFP Boiling 14 5-7hrs Isolate SI Accumulators N 1/2BFSG -10 15 12 hrs Initiate SFP Make up via OA FC Purification pump as NA OBFSG-ll required for level and temperature control 16 12 - 14 hrs Connect Phase 2 med head FLEX Pumps and ensure NA 1/2BFSG-5 they are available to supply make-up to the SG's.
17 14-16hrs Hook up FLEX DG to restore power to a SX Tower 480 NA OBFSG-5 substation "Z" Bus for Deep Well Pump, (WW) 18 16-18hrs Stage and connect Phase 2 high pressure FLEX Pumps NA 1I2BFSG-5 and ensure they are available to supply borated make-up to the RCS.
19 20-22 hrs Establish Well Water as a makeup source of clean water N/A OBFSG-5 Page 27 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 20 24hrs Regional Response Center (RRC) resources begin NA RRC Response arriving on site. Guide 21 24 72hrs Continue to maintain critical functions of Core Cooling NA End of analytical (via DDAF), RSC Inventory Control (via FLEX pump I simulation injection to RCS) and SFP Cooling (via FLEX pump injection to SFP). Utilize initial RRC equipment and resources as a spare capacity.
Page 28 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28, 2014 Attachment 3 Updated Mechanical One Line Diagrams I
I
~"l.
"" ~~~~! ~"O<<
I EXElON NIJCLt4R BY'll!}/; l'OWf R SlAllON Slt.lP,IF1ED FLEX C.£SIGN l.<iT;GAnO~ ST"-'ITEG;ES Page 29 of 30
Byron Station, Units 1 and 2- Second Six Month Status Report for the Implementation of FLEX February 28,2014
.. ------ --- --- --- -- -- -------- ---------1
!i f ..- .
lW1~~
18/28 )G =IESE~ OIL ,t$l)'lID % '"'V :
i
- TRANSFER SYSTEM MOOS lr _ >J-l--- 'f :
\ 2$'I111:::=!. :
1 E"tLON NUCLEAR IlYllON "O'IItR S'AHON SIMPLIFiED FLEX DESIGN V[iICAHON 5rqAl~CItS URS
~ . _"1--'-----
Page 30 of 30