RS-16-235, Fifth Six-Month Status Report for Phases 1 and 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe

Fifth Six-Month Status Report for Phases 1 and 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe

ML16350A265
Person / Time
Site:	Peach Bottom
Issue date:	12/15/2016
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-109, RS-16-235
Download: ML16350A265 (23)

Text

{{#Wiki_filter:Exelon Generation. RS-16-235 December 15, 2016 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Peach Bottom Atomic Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-44 and DPR-56 NRC Docket Nos. 50-277 and 50-278 Order No. EA-13-109

Subject:

Fifth Six-Month Status Report For Phases 1 and 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109)

References:

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

2. NRC Interim Staff Guidance JLD-ISG-2013-02, "Compliance with Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions", Revision 0, dated November 14, 2013

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

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

5. Exelon Generation Company, LLC's Answer to June 6, 2013, Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 26, 2013

6. Exelon Generation Company, LLC Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 30, 2014 (RS-14-062)

7. Exelon Generation Company, LLC First Six-Month Status Report Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated December 19, 2014 (RS-14-305)

8. Exelon Generation Company, LLC Second Six-Month Status Report Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 30, 2015 (RS-15-151)

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 December 15, 2016 Page 2

9. Exelon Generation Company, LLC Phase 1 (Updated) and Phase 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated December 15, 2015 (RS-15-303)

10. Exelon Generation Company, LLC Fourth Six-Month Status Report For Phases 1 and 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 30, 2016 (RS-16-109)

11. NRG letter to Exelon Generation Company, LLC, Peach Bottom Atomic Power Station, Units 2 and 3 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 1 of Order EA-13-109 (Severe Accident Capable Hardened Vents) (TAC Nos.

MF4416 and MF4417), dated February 12, 2015

12. NRG letter to Exelon Generation Company, LLC, Peach Bottom Atomic Power Station, Units 2 and 3 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 2 of Order EA-13-109 (Severe Accident Capable Hardened Vents) (TAC Nos.

MF4416 and MF4417), dated August 2, 2016 On June 6, 2013, the Nuclear Regulatory Commission ("NRG" or "Commission") issued an Order (Reference 1) to Exelon Generation Company, LLC (EGG). Reference 1 was immediately effective and directs EGG to require their BWRs with Mark I and Mark II containments to take certain actions to ensure that these facilities have a hardened containment vent system (HCVS) to remove decay heat from the containment, and maintain control of containment pressure within acceptable limits following events that result in loss of active containment heat removal capability while maintaining the capability to operate under severe accident (SA) conditions resulting from an Extended Loss of AC Power (ELAP). Specific requirements are outlined in Attachment 2 of Reference 1. Reference 1 required submission of an Overall Integrated Plan (OIP) by June 30, 2014 for Phase 1 of the Order, and an OIP by December 31, 2015 for Phase 2 of the Order. The interim staff guidance (References 2 and 3) provide direction regarding the content of the OIP for Phase 1 and Phase 2. Reference 3 endorses industry guidance document NEI 13-02, Revision 1 (Reference 4) with clarifications and exceptions identified in References 2 and 3. Reference 5 provided the EGG initial response regarding reliable hardened containment vents capable of operation under severe accident conditions. Reference 6 provided the Peach Bottom Atomic Power Station, Units 2 and 3, Phase 1 OIP pursuant to Section IV, Condition D.1 of Reference 1. References 7 and 8 provided the first and second six-month status reports pursuant to Section IV, Condition D.3 of Reference 1 for Peach Bottom Atomic Power Station. Reference 9 provided the Peach Bottom Atomic Power Station, Units 2 and 3, Phase 1 updated and Phase 2 OIP pursuant to Section IV, Conditions D.2 and D.3 of Reference 1. Reference 1 O provided the fourth six-month status report pursuant to Section IV, Condition D.3 of Reference 1 for Peach Bottom Atomic Power Station. The purpose of this letter is to provide the fifth six-month update report for Phases 1 and 2, pursuant to Section IV, Condition D.3 of Reference 1, that delineates progress made in implementing the requirements of Reference 1 for Peach Bottom Atomic Power Station, Units 2 and 3. 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

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 December 15, 2016 Page 3 the basis, if any. The enclosed report also addresses the NRC Interim Staff Evaluation open items contained in References 11 and 12. 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 151h day of December 2016. Respectfully submitted, James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosure:

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for Phases 1 and 2 Implementation of Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region I NRC Senior Resident Inspector - Peach Bottom Atomic Power Station NRC Project Manager, NRA - Peach Bottom Atomic Power Station Mr. Raj Auluck, NRR/JLD/TSD/JCBB, NRC Mr. Brian E. Lee, NRR/JLD/JCBB, NRC Mr. Peter Bamford, NRR/JLD/JOMB, NRG Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Resources R. R. Janati, Chief, Division of Nuclear Safety, Pennsylvania Department of Environmental Protection, Bureau of Radiation Protection S. T. Gray, State of Maryland

Enclosure Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for Phases 1 and 2 Implementation of Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (19 pages)

Enclosure Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for Phases 1 and 2 Implementation of Order EA-13-109, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions" 1 Introduction Peach Bottom Atomic Power Station (PBAPS) developed an Overall Integrated Plan (Reference 1 in Section 8), documenting the installation of a Hardened Containment Vent System (HCVS) that provides a reliable hardened venting capability for pre-core damage and under severe accident conditions, including those involving a breach of the reactor vessel by molten core debris, in response to Reference 2. This is the second six-month status report updating milestone accomplishments based on the combined Phases 1 and 2 Overall Integrated Plan dated December 15, 2015. PBAPS developed an updated and combined Phases 1 and 2 Overall Integrated Plan (Reference 6 in Section 8), documenting: 1. The installation of a Hardened Containment Vent System (HCVS) that provides a reliable hardened venting capability for pre-core damage and under severe accident conditions, including those involving a breach of the reactor vessel by molten core debris, in response to Reference 2.

2. An alternative venting strategy that makes it unlikely that a drywall vent is needed to protect the containment from overpressure related failure under severe accident conditions, including those that involve a breach of the reactor vessel by molten core debris, in response to Reference 2 This enclosure provides an update of milestone accomplishments since submittal of the Fourth Six-Month Status Report for Phase 1 and Phase 2 Overall Integrated Plan, 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 the development of the combined Phases 1 and 2 Overall Integrated Plan (Reference 6), and are current as of December 2, 2016: Fifth Six-Month Update (complete with this submittal) Unit 2 achieved compliance with Phase 1 requirements on November 10, 2016 3 Milestone Schedule Status The following provides an update to Attachment 2 of the combined Phases 1 and 2 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. Page 1of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Target Activity Comments Milestone Completion Status Date Phases 1 and 2 HCVS Milestone Table Submit Overall Integrated Plan Jun. 2014 Complete Submit 6 Month Updates Update 1 Dec.2014 Complete Update 2 Jun.2015 Complete Update 3 [Simultaneous with Phase 2 Dec. 2015 Complete OIP] Update 4 Jun.2016 Complete Complete Update 5 Dec.2016 with this submittal Update 6 Jun.2017 Not Started Update 7 Dec.2017 Not Started Update 8 Jun.2018 Not Started Update 9 Dec.2018 Not Started Phase 1 Specific Milestones Phase 1 Unit 2 Modifications Begin Conceptual Design Apr. 2014 Complete Complete Conceptual Design Jun.2015 Complete Begin Detailed Design Jun.2015 Complete Complete Detailed Design and Issue Jun.2016 Complete Modification Package Begin Online Portion of the Installation Jun.2016 Complete Complete Online Installation Oct. 2016 Complete Begin Outage Portion of the Installation Oct. 2016 Complete Complete Outage Installation Nov. 2016 Complete Phase 1 Procedure Changes Active Operations Procedure Changes Nov. 2016 Complete Developed Page 2of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Target Activity Comments Milestone Completion Status Date Phases 1 and 2 HCVS Milestone Table Site Specific Maintenance Procedure Nov. 2016 Complete Developed Procedure Changes Active Nov. 2016 Complete Phase 1 Training Training Complete Nov. 2016 Complete Phase 1 Completion Unit 2 Phase 1 HCVS Implementation Nov. 2016 Complete Phase 1 Unit 3 Modifications Begin Conceptual Design N/A N/A Complete Conceptual Design N/A N/A Begin Detailed Design May 2016 Complete Complete Detailed Design and Issue Date Change: Modification Package Feb.2017 Started Previously Oct. 2016 Date Change: Begin Online Portion of the Installation Mar. 2017 Not Started Previously Feb.2017 Date Change: Complete Online Installation Oct. 2017 Not Started Previously Jun.2017 Begin Outage Portion of the Installation Oct. 2017 Not Started Complete Outage Installation Nov. 2017 Not Started Phase 1 Procedure Changes Active Operations Procedure Changes Nov. 2017 Not Started Developed Site Specific Maintenance Procedure Nov. 2017 Not Started Developed Procedure Changes Active Nov. 2017 Not Started Phase 1 Training Training Complete Nov. 2017 Not Started Page 3of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Target Activity Comments Milestone Completion Status Date Phases 1 and 2 HCVS Milestone Table Phase 1 Completion Unit 3 Phase 1 HCVS Implementation Nov. 2017 Not Started Phase 2 Specific Milestones Phase 2 Unit 3 Modifications Begin Conceptual Design May 2016 Complete Date Change: Complete Conceptual Design Nov. 2016 Complete Previously Jul. 2016 Date Change: Begin Detailed Design Dec.2016 Not Started Previously Jul. 2016 Complete Detailed Design and Issue Date Change: Modification Package Feb.2017 Not Started Previously Oct. 2016 Date Change: Begin Online Portion of the Installation Mar. 2017 Not Started Previously Feb. 2017 Date Change: Complete Online Installation Oct. 2017 Not Started Previously Jun.2017 Begin Outage Portion of the Installation Oct. 2017 Not Started Complete Outage Installation Nov. 2017 Not Started Phase 2 Procedure Changes Active Operations Procedure Changes Nov. 2017 Not Started Developed Site Specific Maintenance Procedure Nov. 2017 Not Started Developed Procedure Changes Active Nov. 2017 Not Started Phase 2 Training Training Complete Nov. 2017 Not Started Phase 2 Completion Page 4of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Target Activity Comments Milestone Completion Status Date Phases 1 and 2 HCVS Milestone Table Unit 3 Phase 2 HCVS Implementation Nov.2017 Not Started Submit Full Compliance Report for Phase 1 Jan.2018 Not Started & Phase 2 for Unit 3 Phase 2 Unit 2 Modifications Begin Conceptual Design N/A N/A Complete Conceptual Design N/A N/A Begin Detailed Design Mar. 2017 Not Started Complete Detailed Design and Issue Sep.2017 Not Started Modification Package Begin Online Portion of the Installation Feb.2018 Not Started Date Change: Complete Online Installation Oct. 2018 Not Started Previously Jun.2018 Begin Outage Portion of the Installation Oct. 2018 Not Started Complete Outage Installation Nov.2018 Not Started Phase 2 Procedure Changes Active Operations Procedure Changes Nov.2018 Not Started Developed Site Specific Maintenance Procedure Nov.2018 Not Started Developed Procedure Changes Active Nov.2018 Not Started Phase 2 Training Training Complete Nov. 2018 Not Started Phase 2 Completion Unit 2 Phase 2 HCVS Implementation Nov. 2018 Not Started Submit Full Compliance Report for Phase 1 Jan.2019 Not Started & Phase 2 for Unit 2 Page 5of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 4 Changes to Compliance Method It was previously communicated in the combined Phases 1 and 2 Overall Integrated Plan (Reference 6) that the existing HCVS radiation monitoring system (RMS) was to be modified for both Unit 2 and Unit 3 such that the FLEX Diesel Generator will provide backup power to the system and that the detector and associated cabling was to be replaced and relocated; however, the existing HCVS RMS will not be modified. A new HCVS RMS was installed for Unit 2 and a new HCVS RMS will be installed for Unit 3 in addition to the existing system. This new HCVS RMS includes a detector assembly (RE-81405) located on elevation 195'-0" of the Unit 2 Reactor Building, processor (RT-81405) located in the Remote Operating Station (ROS), and indicator (Rl-81405) located in Main Control Room Panel 20C010. The FLEX Diesel Generator will provide backup power to the new HCVS RMS. The new HCVS RMS is designed to align with the guidance provided in NEI 13-02, Rev. 1 (Reference 3). The installed capacity of the argon purge system was also previously communicated in the combined Phases 1 and 2 Overall Integrated Plan (Reference 6) to be sized for at least 8 purges within the first 24 hours of an ELAP. A generic number of 8 Wetwell vent cycles within the first 24 hours of an ELAP is determined to be reasonable per HCVS-WP-02 (Reference 9). HCVS-WP-02 also states that the number of vent cycles is dependent on the strategy and scenario selected for the evaluation and a plant specific analysis can be used to determine the number of cycles estimated during the first 24 hours. The generic number of 8 Wetwell vent cycles is based on a 20 psi pressure control band for containment pressure. Peach Bottom will utilize a 41 psi pressure control band (15 - 56 psig). The high end of the pressure control band (56 psig) is the Primary Containment Design Pressure for Peach Bottom and the low end of the pressure control band (15 psig) is based on EPRI Severe Accident Management Guidance Technical Basis Report, Volume 2, Appendix S. Using this pressure control band, a Modular Accident Analysis Program (MAAP) calculation (Reference 11) was developed using MAAP 4.0.6. This analysis resulted in a MAAP calculation of four (4) containment vent cycles within the first 24 hours of an ELAP. Based on the results of this analysis, the installed capacity of the argon purge system will be sized for at least 4 purges within the first 24 hours of an ELAP. There are no other changes to the compliance method outlined in Reference 6. 5 Need for Relief/Relaxation and Basis for the Relief/Relaxation PBAPS expects to comply with the order implementation date and no relief/relaxation is required at this time. 6 Open Items from Combined Phases 1 and 2 Overall Integrated Plan and Interim Staff Evaluations The following tables provide a summary of the open items documented in the combined Phases 1 and 2 Overall Integrated Plan or the Interim Staff Evaluation (ISE) for Phase 1 and Phase 2 and the status of each item. Page 6of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Combined Phases 1 Status and 201P Open Item Phase 1 Open Items 01-1. Confirm Deleted. Closed to ISE Open Item number 09. that the Remote Operating Station (ROS) will be in an accessible area following a Severe Accident (SA). 01-2. Provide Deleted. Closed to ISE Open Item number 01. procedures forHCVS Operation 01-3. Identify Deleted. Closed to ISE Open Item number 02. site specific controlling document for HCVS out of service and compensator y measures 01-4. Deleted. Closed to ISE Open Item number 08. Determine the approach for combustible gases. 01-5. Perform Complete - This evaluation is captured in Calculation PM-1190. Calculation radiological PM-1190 has been posted to the ePortal and a summary of the results is evaluation for provided below: Phase 1 vent line impact on ERO response actions. Page 7of19

Combined Phases 1 and 201P Open Item Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Status Table 8-1 Operating ;::,iation and Equipment Location Dose Rates and Integrated Doses Distance Concrete Peak Event 7-03'/ Location from Shield Dose Rate Integrated Vent Pipe Thickness (Rlhr) Dose Cinches) IRl Primary Operating Station >100 It >60 (1) (POS\\ Units2and 3 40 ft (Unit 2) 54 (Unit 2) Remote Operating Station (ROS) >100 ft (Unit 42 (Unit 3) 5.684E-03 4.281E-01

3)

HCVS Batteries > 100 ft >60 1.574E-04 1.186E-02 Equipment in MCR >100 It >60 (1) re.a. HCVS monitorina) Valve Operators: 1 cm 0 3.220E+05i~ i 8.036E+06 A0-2511 A0-80290 and A0-2512 Radiation Monitor Detector Assembly 1 cm 0 6.605E+04 4.963E+06 Temperature Element Tl-81407 Within 0 4.505E+05m 1.769E+07 Wellm (1) Not required per Ncl 13-02 HCVS-FAQ-01 [t<ererence 4.1). (2) Dose rate contribution from wetwell induded. TIO (EO Qualified Dose) (R) 350 90 8.0E+06 C1E+07l 5.0E+vo C2.0E+08) 1.t1t+tJ7 (3.00E+08) (3) Although lhe temperature element is at the surface of the HCVS vent pipe, the 7-day integrated radiation dose is conservatively calculated for a thermal well wrthin the pipe. Table 8-2 Vent Pipe Peak Dose Rates at FLEX Equipment Locations Peach Bottom Distance Concrete Shield Peak Event Location Unit in from Thickness Dose Rate Severe Accident Vent Pioe Cinches\\ IR/hd tl Unit 2 Diesel Generator 2 250 ft 30 2.740E-03 3 450 ft >60 7.87 1E-05 Unit 3 Diesel Generator 2 450 ft >60 7.87 1E-05 3 250 ft 30 2.740E-03 Refueling Station 2 200 ft (2\\ (2\\ 3 400 ft >60 (2\\ FLEX Pump (Flood Event) 2 -600 ft 8 1.50E-0 1 3 --400 ft 8 5.60E-0 1 FLEX Pump (Seismic Event) 2 -600 ft 0 (for too 20* to 33* of Pioe\\ 8.84E-0 1 3 - 500 ft 0 (for too 20" to 33" of Pin..\\ 8.84E-0 1 ( 1) Although the shielded direct dose rates are small due to the radiation shielding, the dose rates at the diesel generator locations are not expected to be insignificant. due to the dose rate contribution from air scattered radiation of the activity within the vent pipe. (2) The refueling station is south of the Unit 2 reactor building south wall. The refueling station must be within the area shielded from the HCVS vent pipe by the shadow of the Unit 2 reactor building south wall. The closer the refueling station is to the turbine building, the smaller will be the scattered dose rate from activity within the HCVS vent pipe. If the refueling station is near the Unit 2 diesel generator location near the reactor bu~d ing equipment access lock, then the direct dose rate will be similar to the reported dose rates for the Unit 2 diesel oenerator. Page 8of19

Combined Phases 1 and 201P Open Item Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Status Table 6-3 Operator Transit Pathway Dose Rates Distance concrete Shield Peak Event Location from Thickness Dose Rate Vent PinP-linchesl (R/hr) Access Pathway to ROS, Reactor Building Northeast stairwell, EL >100 ft (2) (2) 165'-0" to 135'-{)" Turbine Building/Reactor Bunding >100 ft 42 4.493E-03 Second Floor EL 165'-0" Reactor Building >100 ft >60 (vent pipe) 2-232E+01 Near Row J EL 135'-0" 2'-8" (wetwelll Service Road' 38 ft O (vent pipe) 5.612E+02°' 'Nest ofReactor Bu ~ding 2'-B" (wetwell) ( 1 ) Dose rate contribution from wetwell included. (2) Refer to the eYaluation in Section 7.8 of this calculation. The dose rate in the stairwell is due to severe accident actiYity within the torus. T he stairwell is above the comer room s in the torus area. Radiation shine from the torus into the stairwell and the stairwell enclosure on EL 135' is shielded by the 2*-s-thick concrete floor aboYe the torus at EL 135' and radiation shine from the torus through a hatch in the floor above the torus. The stairwell enclosure has a 1 o* thick concrete wall and there is a doorway into the stairwell enclosure. The dose rate in the stairwell enclosure is estimated to be be in the range of 0.5 Rlhr to 11 Rlhr and the dose rate on the stairs is estimated to range from 30 to 11 Rlhr with the highest dose rate due to shine through the floor hatch into the stairwell. (3) Use of the service road west of the reactor building as a traYel pathway vollowing HCVS Yent initiation is not viable due to the large do se rates. Page 9of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Phase 1 Interim Staff Evaluation Open Item ISE-1. Make available for NRC staff audit guidelines and procedures for HCVS operation. (Section 3.2.3.1) Status Complete - guidelines and procedures for HCVS operation are complete and posted to the ePortal. A list of the guidelines and procedures for HCVS operation is provided below: AO 56E.2-3, Rev 013, E134-T-B, E134-W-A, AND E-13A4-EC-A MOTOR CONTROL CENTERS OR E134 AND E13A4 EMERGENCY AO 56E.4-2, Rev 019, E324-R-B, E324-R-D, E324-D-A, E324-T-B OR E324-0-A MOTOR CONTROLCENTERS OR E324 EMERGENC CC-PB-118, Rev 003, PEACH BOTTOM IMPLEMENTATION OF DIVERSE AND FLEXIBLE COPING STRATEGIES (FLEX) AND SP FSG-010-2, Rev 001, ALIGNING FLEX GENERATOR TO PANEL 2AS1061 AND FOR FUEL OIL TRANSFER FSG-010-3, Rev 001, ALIGNING FLEX GENERATOR TO PANEL 3AS1061 FSG-011-2, Rev 0000, ALIGNING FLEX GENERATOR TO PANEL 2BS1061 AND FOR FUEL OIL TRANSFER FSG-011-3, Rev 001, ALIGNING FLEX GENERATOR TO PANEL 3BS1061 FSG-013-2, Rev 0000, ELAP AC LOAD ALIGNMENT FSG-013-3, Rev 001, ELAP AC LOAD ALIGNMENT GP-2-2, Rev 008, NORMAL PLANT START-UP OP-PB-108-103-2, Rev 007, LOCKED VALVE LIST-PBAPS UNIT 2 PF-72H, Rev 007, RADWASTE BLDG RADWASTE COMPACTING AND STORAGE - ELEVATION 135'-0" PF-75, Rev 006, RADWASTE BLDG RADWASTE CONTROL ROOM DEGON AND MEDICAL STATION ELEVATION 135'-0" RT-M-07B-950-2, Rev 003, TORUS HARDENED VENT RUPTURE DISC INTEGRITY TEST RT-0-07K-900-2, Rev 0000, CONTAINMENT EMERGENCY VENT SYSTEM BOTTLE PRESSURE VERIFICATION TEST RT-0-57P-100-2, Rev 0000, CONTAINMENT EMERGENCY VENT SYSTEM COMPONENT OPERATION TEST RT-0-57P-745-2, Rev 0000, CONTAINMENT EMERGENCY VENT BATTERY MONTHLY INSPECTION RT-0-57P-746-2, Rev 0000, CONTAINMENT EMERGENCY VENT BATTERY QUARTERLY INSPECTION RT-0-100-505-2, Rev 040, EMERGENCY OPERATING PROCEDURE TOOL INVENTORY SE-4 BASES, Rev 031, FLOOD - BASES SE-4 PROCEDURE, Rev 041, FLOOD - PROCEDURE SE-11 BASES, Rev 022, LOSS OF OFF-SITE POWER - BASES SO 7B.1.A-2 COL, Rev 011, CONTAINMENT ATMOSPHERE INERTING SO 7K.1.A-2 COL, Rev 0000, CONTAINMENT EMERGENCY VENT ARGON RUPTURE PURGE SO 16C.1.A-2 COL, Rev 001, BACKUP INSTRUMENT NITROGEN TO HARDENED CONTAINMENT VENT SYSTEM SO 57P.1 COL, Rev 0000, CONTAINMENT EMERGENCY VENT SYSTEM SO 57P.1, Rev 001, HARDENED CONTAINMENT VENT SYSTEM BATTERY CHARGER STARTUP AND NORMAL OPERATIONS SO 58C.1.A COL, Rev 047, NORMAL 120 VAC SYSTEM COMMON PLANT ST/LLRT 20.07B.11, Rev 003, TORUS 18 INCH VENT ISOLATION VALVES TO S.B.G.T. 0-RING SEALS OF A0-2-07B-2511 ST-M-16B-250-2, Rev 019, SAFETY GRADE INSTRUMENT GAS SYSTEM FUNCTIONAL AND INSERVICE TEST T-200-2, Rev 014, PRIMARY CONTAINMENT VENTING T-200J-2, Rev 004, CONTAINMENT VENTING VIA THE TORUS HARDENED VENT TQ-PB-201-0113, Rev 008, PEACH BOTTOM TRAINING DEPARTMENT SIMULATOR EXAMINATION SECURITY Page 10of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Phase 1 Interim Staff Evaluation Open Item ISE-2. Make available for the NRG staff audit the site specific controlling document for HCVS out of service and compensatory measures. (Section 3.4.1) ISE-3. Make available for NRC staff audit a technical justification for use of jumpers in the HCVS strategy. (Section 3.1.3) Status Complete - Procedure CC-PB-118 contains HCVS out of service requirements and is posted to the ePortal. Out of service requirements are described below: Hardened Containment Vent System (HCVS) Applicability: Modes 1, 2, and 3 Note: Multiple Condition entry is allowed for each piece of equipment. A. B.

c.

Condition Primary control and monitoring elements 1 OR Alternate valve control elements 1 Primary control and monitoring elements AND Alternate valve control elements Required Action A or B and associated Completion Time Not Met. Required Action Restore capability. Restore primary control and monitoring elements. OR Restore alternate valve control elements. Initiate an IR to enter the condition into CAP. Determine the cause of the non-functionality. Determine the actions to be taken and the schedule for restoring the system to functional status and prevent recurrence. Initiate action to implement appropriate compensatory actions. Restore full HCVS functionality at the earliest opportunity not to exceed one full operatinQ cycle. Completion Time 90 days 30 days Immediately 1The HCVS is functional when piping, valves, instrumentation and controls including motive force necessary to support system operation are available. The HCVS primary control and monitoring elements includes the following: Argon and nitrogen bottle banks MCR controls MCR indications of HCVS argon header pressure, vent line temperature, and vent path valve position indication. HCVS Battery and Battery Charger Capability to cycle open and close vent path valves from the MCR The HCVS alternate control elements include: Argon and nitrogen bottle banks Capability to cycle open and close vent path valves from the Remote Operating Station (ROS), RW 135' Complete - The design of the HCVS includes a control switch in the MCA for transferring power to the solenoid valve (SV) that does not include a PCIS isolation signal, eliminating the need for jumpers. Applicable Unit 2 drawings (M-1-S-23, Sheet 34B and E-403, Sheet 5) and Unit 2 ECR package 15-00148 have been uploaded to the ePortal. Page 11of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Phase 1 Interim Staff Evaluation Open Item ISE-4. Make available for NRC staff audit analyses demonstrating that the HCVS has the, capacity to vent the steam/energy equivalent of one percent of licensed/rated thermal power (unless a lower value is justified), and that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit. (Sections 3.2.2.1 and 3.2.2.2) ISE-5. Make available for NRC staff audit descriptions or diagrams of reactor building ventilation including exhaust dampers failure modes to support licensee justification for the HVAC release point being below and 150 feet from the reactor building ventilation release point. (Section 3.2.2.3) Status Complete - Calculation PM-0546, Torus Hardened Vent-Flow demonstrates that the HCVS has the capacity to vent the steam/energy equivalent of one percent licensed/rated thermal power. The primary containment design pressure is 56 psig (UFSAR 5.2.3.1 ). The primary containment pressure limit is 60 psig (UFSAR 5.2.3.6). PM-0546 shows that the HCVS capacity exceeds one percent of licensed/rated thermal power at the lower of these values. Calculation PM-0546 has been uploaded to the ePortal. Additionally, MAAP calculation PB-MISC-025 was developed using MAAP 4.0.6 to investigate the response of Peach Bottom Unit 2 and Unit 3 containment venting using the HCVS vent parameters and the use of RPV alternate injection with assumed immediate RCIC failure. The MAAP analysis demonstrates that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit. Calculation PB-MISC-025 has been uploaded to the ePortal. Complete - Reference drawing M-395: The Reactor Building Exhaust System. The RB Exhaust System Fans, including the Refuel Floor Exhaust Fans, RB Exhaust Fans, and RB Equipment Exhaust Fans, have Fail-Close dampers in exhaust ducts to prevent uncontrolled or unmonitored release from the RB in the event of loss of power to the solenoid valves associated with the dampers. Fail-Close dampers will eliminate pathway into the RB in the event of use of the HCVS in an ELAP. Drawing M-395 has been uploaded to the ePortal. Page 12of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report tor the Implementation of HCVS Phases 1 and 2 December 15, 2016 Phase 1 Interim Staff Evaluation Open Item ISE-6. Make available for NRG staff audit details to justify the deviation from tornado protection standards provided in NEI 13-02 or make available a description of how the HCVS will comply with the tornado protection standards provided in NEl 02. (Section 3.2.2.3) ISE-7. Make available for NRG staff audit documentation that demonstrates adequate communication between the remote HCVS operation locations and HCVS decision makers during ELAP and severe accident condition. (Section 3.2.2.5) ISE-8. Provide a description of the final design of the HCVS to address hydrogen detonation and deflagration. (Section 3.2.2.6) Status Complete - Exelon has prepared a Tornado Missile TORMIS analysis (ARA-002611) which calculated probabilities of damage to the external piping that would crimp the pipe to a point of not being able to perform as expected under severe accident conditions following an ELAP event. The conclusions of the analysis are provided below: The table below summarizes the arithmetic sum and Boolean union of hit and damage frequencies per year for each of the targets that comprise the Unit 2 and Unit 3 Hardened Vents. The Boolean union is lower than the arithmetic sum of the frequencies because it eliminates double counting when multiple segments of a single vent are hit (or damaged) in the same event. Frequencies for the Hardened Vent targets for each unit are lower than the threshold frequency of 1.0E-06 per year established in the USN RC (1983b). Mean Damage Frequency (per Year) for PBAPS Hardened Vent Targets Target Hit Probability (per year) 1Dama2e Probability (per veu*) Sum Union Sum Union U2 Hardened Vent 4.60E-05 3.00E-05 l.09E-07 l.05E-07 U3 Hardened Vent l.36E-04 7.02E-05 L31E-07 1.26E-07 In addition, compensatory measures are available in the event the HCVS external piping does become crimped. This analysis has been reviewed by the NRG and determined to be acceptable based on the probability values provided in the analysis and the qualitative reasonable assurance argument provided. TORMIS analysis ARA-002611 has been posted to the ePortal. Complete - FLEX modification ECR 15-00126 improved the PBAPS communication system to be functional in the event of an ELAP. This modification provided equipment and connections to form a workable system to provide in-plant communications during and after an ELAP/BDBEE. The existing 3-way antenna coupler located in the northeast corner of the reactor building at El. 135'-0", was replaced with a 4-way coupler to accommodate a new connection installed from a new cabinet to power the existing plant antenna network. The new cabinet is located in the same area and was vendor supplied with all equipment as required. The cabinet houses an 8-hour rectifier power system and associated batteries, radio repeater that duplicates the frequency of the operations channel 1 (ops 1 ), a radio frequency duplexer to control the signals to and from the portable radio antenna and associated cabling that will be deployed after the event. The cabinet is powered from a division 1 power source which will be powered from the FLEX portable diesel during an ELAP. The permanently installed equipment in the reactor building along with all conduits for the cabling are seismically mounted. This system is deployed using procedure FSG-020. Operators in the remote HCVS operating location (Radwaste Building El. 135') will utilize this system to communicate with the Main Control Room staff. ECR 15-00126 and procedure FSG-020 have been uploaded to the ePortal. Complete - Peach Bottom will utilize an Argon purge system to address combustible gases in the HCVS piping. A summary of the design features is included in the December 2015 OIP. Page 13of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Phase 1 Interim Staff Evaluation Open Item ISE-9. Make available for NRG staff audit an evaluation of temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment. (Sections 3.2.1, 3.2.2.3, 3.2.2.4, 3.2.2.5, 3.2.2.10, 3.2.4.1, 3.2.4.2, 3.2.5.2, and 3.2.6) ISE-10. Make available for NRG staff audit descriptions of all instrumentation and controls (existing and planned) necessary to implement this order including qualification methods. (Sections 3.2.2.9 and 3.2.2.10) ISE-11. Make available for NRG staff audit the final sizing evaluation for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation. (Sections 3.2.2.4, 3.2.3.1, 3.2.3.2, 3.2.4.1, 3.2.4.2, 3.2.5.1, 3.2.5.2, and 3.2.6) Status Complete - Temperature and radiological conditions have been evaluated. The evaluated conditions support safe access and operation of control and supporting equipment by operating personnel. Temperature conditions are evaluated in Section 3.14 of ECR 15-00148 and radiological conditions are evaluated in Calculation PM-1190. Unit 2 ECR 15-00148 and Calculation PM-1190 have been posted to the ePortal. Complete - Descriptions of all instrumentation and controls necessary to implement this order including qualification methods are provided in ECR 15-00148, Section 3.2, 3.5, 3.14, 3.15 & 3.39. ECR 15-00148 has been posted to the ePortal. Complete - Final sizing evaluation for HCVS battery/battery charger is contained in Calculation PE-0308. Incorporation of HCVS loading to FLEX DG loading is contained in Calculation PE-0301. Calculations PE-0308 and PE-0301 have been posted to the ePortal. Page 14of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Phase 1 Interim Staff Evaluation Open Item ISE-12. Make available for NRC staff audit the descriptions of local conditions (temperature, radiation and humidity) anticipated during ELAP and severe accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, etc.) required for HCVS venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions. (Sections 3.2.2.3, 3.2.2.5, 3.2.2.9, and 3.2.2.10) ISE-13. Make available for NRC staff audit documentation of an evaluation verifying the existing containment isolation valves, relied upon for the HCVS, will open under the maximum expected differential pressure during BDBEE and severe accident wetwell venting. (Section 3.2.2.9) ISE-14. Provide a description of the strategies for hydrogen control that minimizes the potential for hydrogen gas migration and ingress into the reactor building or other buildings. (Section 3.2.2.6 and 3.2.2.7) Status Complete - Descriptions of local conditions and confirmation that components required for HCVS venting are capable of performing their functions during ELAP and severe accident conditions are contained in ECR 15-00148, Sections 3.14 & 3.15. Unit 2 ECR 15-00148 has been posted to the ePortal. Complete - Documentation that the existing containment isolation valves, which are relied upon for HCVS, will open under the maximum expected differential pressure during BDBEE and severe accident wetwell venting (60 psig) is provided in specification M-00117 and valve data sheet DS-FP, Sheet 1161. Specification M-00117 requires that PCIV A0-2(3)- 078-2(3)511 be able to operate with a 62 psig pressure differential and valve data sheet DS-FP, Sheet 1161 states that the design pressure of PCIV A0-2(3)-07b-8(9)0290 is 150 psig. Specification M-00117 and valve data sheet DS-FP, Sheet 1161 have been posted to the ePortal. Completed - As described in the OIP, the HCVS torus vent path in each unit, starting at and including the downstream PCIV, will be a dedicated HCVS flow path. There are no interconnected systems downstream of the downstream, dedicated HCVS PCIV. Interconnected systems are upstream of the downstream HCVS PCIV and are isolated by normally shut, fail shut PCIVs which, if open, would shut on an ELAP. There is no shared HCVS piping between the two units. The vent path will rely on an Argon purge system to prevent the formation of a combustible gas mixture in the vent line. Page 15of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Phase 1 Interim Staff Evaluation Open Item ISE-15. Make available for NRG audit documentation confirming that HCVS will remain isolated from standby gas treatment system during ELAP and severe accident conditions. (Section 3.2.2.7) Phase 2 Interim Staff Evaluation Open Item ISE-1. Licensee to demonstrate the SAWA equipment and controls, as well as ingress and egress paths for the expected severe accident conditions (temperature, humidity, radiation) for the sustained operating period. (Section 3.3.2.3) ISE-2. Licensee to demonstrate that instrumentation and equipment being used for SAWA and supporting equipment is capable to perform for the sustained operating period under the expected temperature and radiological conditions. (Section 3.3.2.3) Status Complete - The Hardened Containment Vent is isolated from the SGTS by valve A0-2-078-2512 (Unit 2) and A0-3-078-3512 (Unit 3). The boot seal of A0-2(3)-078-2(3)512 will be maintained inflated from the dedicated HCVS nitrogen supply to ensure that A0-2(3)-078-2(3)512 remains closed/isolated. Unit 2 ECR 15-00148 has been posted to the ePortal. Status Started. Started. Page 16of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Phase 2 Interim Staff Evaluation Status Open Item ISE-3 Licensee to Started. demonstrate that containment failure as a result of overpressure can be prevented without a drywell vent during severe accident conditions. (Section 3.3.3) ISE-4 Licensee Started. shall demonstrate whether a site specific MAAP evaluation will be used to determine an initial SAWA flow rate. If the evaluations performed in BWROG TP 011 is considered, provide a description of how the plant is bounded by the reference plant analysis that shows the SAWM strategy is successful in making it unlikely that a drywell vent is needed. (Section 3.3.3.10) ISE-5 Licensee to Started. demonstrate that there is adequate communication between the MCR and the Intake Structure operator at the FLEX manual valve during severe accident conditions. (Section 3.3.3.4) Page 17of19

Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016 Phase 2 Interim Staff Evaluation Status Open Item ISE-6 Licensee to Started. demonstrate the SAWMflow instrumentation qualification for the expected environmental conditions. (Section 3.3.3.4) 7 Interim Staff Evaluation Impacts There are no potential impacts to the Interim Staff Evaluation(s) identified at this time. 8 References The following references support the updates to the combined Phases 1 and 2 Overall Integrated Plan described in this enclosure.

1. Peach Bottom Atomic Power Station, Units 2 and 3, Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109)," dated June 30, 2014.

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

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

4. NRG Interim Staff Guidance JLD-ISG-2013-02, "Compliance with Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision O, dated November 2013 (Accession No. ML13304B836).

5. NRG Endorsement of Industry "Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Template (EA-13-109) Rev O" (Accession No. ML14128A219).

6. Peach Bottom Atomic Power Station, Units 2 and 3, Combined Phases 1 and 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109)," dated December 15, 2015.

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Peach Bottom Atomic Power Station, Units 2 and 3 Fifth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 December 15, 2016

7. NRC Interim Staff Guidance JLO-ISG-2015-01, "Compliance with Phase 2 of Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision 0, dated April 2015 (Accession No. ML15104A118).

8. Peach Bottom Atomic Power Station, Units 2 and 3, Fourth Six-Month Status Report for Phase 1 and Phase 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109),

dated June 30, 2016 (RS-16-109).

9. HCVS-WP-02, Rev. 0, Sequences for HCVS Design and Method for Determining Radiological Dose from HCVS Piping, dated October 23, 2014.

10. EPRI Severe Accident Management Guidance Technical Basis Report, Volume 2: The Physics of Accident Progression, dated October 2012.

11. PB-MISC-025, Rev. 0, MAAP Analysis to Support HCVS Design: Containment Vent Cycling, dated October 12, 2016. Page 19of19}}