RS-18-059, Eighth 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

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Eighth 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
ML18180A029
Person / Time
Site: Limerick Constellation icon.png
Issue date: 06/29/2018
From: Jim Barstow
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-109, RS-18-059
Download: ML18180A029 (27)
v • d • e


Text

Exelon Generation ~,

Order No. EA-13-109 RS-18-059 June 29, 2018 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 2 Renewed Facility Operating License No. NPF-85 NRG Docket No. 50-353

Subject:

Eighth 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 0, 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-14-060)
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 17, 2014 (RS-14-304)
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-15-150)

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 June 29, 2018 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-15-301)
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-16-108)
11. Exelon Generation Company, LLC 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), dated December 15, 2016 (RS-16-234)
12. Exelon Generation Company, LLC Sixth 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, 2017 (RS-17-066)
13. Exelon Generation Company, LLC Seventh 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 December 15, 201 7 (RS-17-153)
14. NRC letter to Exelon Generation Company, LLC , Limerick Generating Station, Units 1 and 2 - 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. MF4418 and MF4419), dated April 1, 2015
15. NRC letter to Exelon Generation Company, LLC, Limerick Generating Station, Units 1 and 2 - 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. MF4418 and MF4419), dated August 2, 2016 On June 6, 2013, 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 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

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 June 29, 2018 Page 3 provided the EGG initial response regarding reliable hardened containment vents capable of operation under severe accident conditions. Reference 6 provided the Limerick Generating Station, Units 1 and 2, Phase 1 Of P 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 0.3 of Reference 1 for Limerick Generating Station. Reference 9 provided the Limerick Generating Station, Units 1 and 2, Phase 1 updated and Phase 2 OIP pursuant to Section IV, Conditions D.2 and D.3 of Reference 1. References 10, 11, 12, and 13 provided the fourth, fifth, sixth, and seventh six-month status reports pursuant to Section IV, Condition D.3 of Reference 1 for Limerick Generating Station.

The purpose of this letter is to provide the eighth 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 Limerick Generating Station, Unit 2. 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 NRG Interim Staff Evaluation open items contained in References 14 and 15.

This letter contains no new regulatory commitments. If you have any questions regarding this report, please contact David J. Distel at 610-765-5517.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 29th day of June 2018.

Respectfully submitted, James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosure:

Limerick Generating Station, Unit 2 Eighth 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

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 June 29, 2018 Page 4 cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region I NRG Senior Resident Inspector - Limerick Generating Station NRG Project Manager, NRR - Limerick Generating Station Mr. Rajender Auluck, NRR/JLD/TSD/JCBB, NRG Mr. Brian E. Lee, NRR/JLD/JCBB, NRG Mr. Peter J. 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

Enclosure Limerick Generating Station, Unit 2 Eighth 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 (22 pages)

Enclosure Limerick Generating Station, Unit 2 Eighth 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 Limerick Generating Station (LGS) developed an Overall Integrated Plan (Reference 7) 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. Updates of milestone accomplishments will be based on the combined Phases 1 and 2 Overall Integrated Plan dated December 15, 2015.

LGS developed an updated and combined Phases 1 and 2 Overall Integrated Plan (Reference 1), 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 combined Phases 1 and 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 December 15, 2017 status report (Reference 16) and are current as of June 1, 2018.

Eighth 6-Month Update Completed with this Submittal Phase 1:

Unit 1 Modifications Evaluation Unit 1 Design Engineering On-site/Complete Unit 1 Implementation Outage Unit 1 Walk Through Demonstration/Functional Test Unit 1 Operations Procedure Changes Developed Unit 1 Site Specific Maintenance Procedure Developed Unit 1 Procedure Changes Active Unit 1 Training Complete Unit 1 HCVS Implementation Phase 2:

Unit 1 Design Engineering On-site/Complete Page 1of22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Unit 1 Implementation Outage Modifications Evaluation Unit 1 Walk Through Demonstration/Functional Test Unit 1 Operations Procedure Changes Developed Unit 1 Site Specific Maintenance Procedure Developed Unit 1 Procedure Changes Active Unit 1 Training Complete Unit 1 HCVS Implementation Unit 2 Design Engineering On-site/Complete 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.

Comments Target Milestone Completion Activity Status {Include date Date changes in this column}

Phases 1 and 2 HCVS Milestone Table Submit Overall Integrated Plan Jun 2014 Complete Reference 7 Submit 6 Month Updates Update 1 Dec 2014 Complete Reference 8 Update 2 Jun 2015 Complete Reference 9 Update 3 [Simultaneous with Phase 2 Reference 1 Dec 2015 Complete OIP]

Update 4 Jun 2016 Complete Reference 12 Update 5 Dec 2016 Complete Reference 14 Update 6 Jun 2017 Complete Reference 15 Update 7 Dec 2017 Complete Reference 16 Jun 2018 Completed with Update 8 this submittal Update 9 Dec 2018 Not Started Update 10 June 2019 Not Started Page 2 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Comments Target Milestone Completion Activity Status {Include date Date changes in this column}

Phases 1 and 2 HCVS Milestone Table Phase 1 Specific Milestones Phase 1 Modifications Hold preliminary/conceptual design Jun 2014 Complete meeting Unit 1 Modifications Evaluation Feb 2018 Complete Unit 2 Modifications Evaluation Mar 2017 Complete Unit 1 Design Engineering On-Feb 2018 Complete site/Complete Unit 1 Implementation Outage Apr2018 Complete Unit 1 Walk Through Apr2018 Complete Demonstration/Functional Test Unit 2 Design Engineering On-May 2017 Complete site/Complete Unit 2 Walk Through May 2017 Complete Demonstration/Functional Test Unit 2 Implementation Outage May 2017 Complete Phase 1 Procedure Changes Active Unit 1 Operations Procedure Changes Feb 2018 Complete Developed Unit 1 Site Specific Maintenance Feb 2018 Complete Procedure Developed Unit 1 Procedure Changes Active Apr2018 Complete Unit 2 Operations Procedure Changes Feb 2017 Complete Developed Unit 2 Site Specific Maintenance Feb 2017 Complete Procedure Developed Page 3 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Comments Target Milestone Completion Activity Status {Include date Date changes in this column}

Phases 1 and 2 HCVS Milestone Table Unit 2 Procedure Changes Active May 2017 Complete Phase 1 Training Unit 1 Training Complete Feb 2018 Complete Unit 2 Training Complete Feb 2017 Complete Phase 1 Completion Unit 1 HCVS Implementation Apr 2018 Complete Unit 2 HCVS Implementation May 2017 Complete Phase 2 Specific Milestones Phase 2 Modifications Hold preliminary/conceptual design Jun 2016 Complete meeting Moved to align Modifications Evaluation Mar 2018 Complete with actu al completion date Unit 1 Design Engineering On-Feb 2018 Complete site/Complete Unit 1 Implementation Outage Apr 2018 Complete Unit 1 Walk Through Apr 2018 Complete Demonstration/Functional Test Unit 2 Design Engineering On-Mar 2018 Complete site/Complete Unit 2 Walk Through Apr2019 Not Started Demonstration/Functional Test Unit 2 Implementation Outage May 2019 Not Started Phase 2 Procedure Changes Active Page 4 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Comments Target Milestone Completion Activity Status {Include date Date changes in this column}

Phases 1 and 2 HCVS Milestone Table Unit 1 Operations Procedure Changes Feb 2018 Complete Developed Unit 1 Site Specific Maintenance Feb 2018 Complete Procedure Developed Unit 1 Procedure Changes Active Apr2018 Complete Unit 2 Operations Procedure Changes Feb 2019 Not Started Developed Unit 2 Site Specific Maintenance Feb 2019 Not Started Procedure Developed Unit 2 Procedure Changes Active May 2019 Not Started Phase 2 Training Unit 1 Training Complete Feb 2018 Complete Unit 2 Training Complete Feb 2019 Not Started Phase 2 Completion Unit 1 HCVS Implementation Apr 2018 Complete Unit 2 HCVS Implementation May2019 Not Started Full Site HCVS Implementation May 2019 Not Started Submit Unit 1, Phase 1 & Phase 2, Completion Report [60 days after Unit Jun 2018 Complete 1 compliance]

Submit Unit 2, Phase 1 & Phase 2, Completion Report [60 days after Unit Jul2019 Not Started 2 compliance]

4 Changes to Compliance Method LGS has completed site specific MAAP evaluations to determine the number of vent cycles required during initial 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the event. Based on the MAAP evaluations, less than 3 cycles are required. Based on MAAP evaluation input, LGS has designed and installed a volume of gases used for purge and PCIV motive force that are sized for a minimum of 24 Page 5 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 hours0.0234 days <br />0.561 hours <br />0.00334 weeks <br />7.67849e-4 months <br /> of operation. The purge gas volume is sufficient for 4 purge cycles and the PCIV motive force (air) volume is sufficient for 8 open cycles. This is in compliance with NEI 13-02 Rev. 1, NRG endorsed HCVS-WP-02 guidance for determining number of vent cycles.

The Primary Containment Pressure Limit (PCPL) value of 60 psig is in Calculation MEL-0138. The design temperature for supports and piping components shall be at least 350 "F to satisfy the recommendations of NEI 13-02. One exception is applied for the maximum operating temperature in relation to the piping and supports HBD-842-H003, H004 and HOOS. Instead of 350°F, 308°F is used as it corresponds to saturated steam at the PCPL pressure of 60 psig. This meets the design intent of the NEI guidance and provides design analysis margin. (Reference EC 422831 section 3.5.2.1) This exception applies to Unit 2 compliance.

LGS implemented operation, testing, and inspection requirements for the HCVS and SAWA that follows the existing plant procedures and process to ensure reliable operation of the systems. The existing plant maintenance program will be applied to the HCVS and SAWA valves, instead of the maintenance frequency that has been listed in NEI 13-02, Section 6.2.4. The maintenance program uses PCM (Performance Centered Maintenance) template which is currently used to maintain the plant's safety related and non-safety related systems.

5 Need for Relief/Relaxation and Basis for the Relief/Relaxation LGS 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) and the status of each item.

Combined Phase 1 and Phase 2 OIP Open Items Status Phase 1 Open Items 01-1 Determine how Motive Power and/or HCVS Batte1)' Closed to !SE -I Power will be disabled during normal operation.

01-2 Confirm that the Remote Operating Station (ROS) will be Closed to !SE-3 in an accessible area following a Severe Accident (SA).

01-3 Determine wetwell line size to meet I % venting criteria. Closed to !SE- 4 01-4 Confirm suppression pool heat capacity. Closed to !SE-4 01-5 Determine the approach for combustible gases. Closed to ISE-9 and ISE-10 01-6 Provide procedures for HCVS Operation. Closed to !SE-13 Page 6 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Combined Phase 1 and Phase 2 OIP Open Items Status Phase 1 Open Items 01-7 Verify the external piping consists solely of large bore Complete. (Reference EC piping and its supports have less than 300 square feet of 423331, Attachment 8 (formally cross section. known as ECR 16-00011 )). EC 423331 is available in ePortal.

01-8 Evaluate drywell pressure indication for e11viro11111ental Unit 1 - Complete.

qualifications to ensure this instrument can survive for 7 Unit 1 Pressure indicator will days after an event. survive the environmental conditions for 7 days after the event. (See EC 423381 for replacement details).

Unit 2 - Complete.

(Reference EC 617568 section 3.2). EC 617568 and EC 423381 are available in ePortal.

01-9 Determine Pe1formance Criteria for Motive gas Cylinders, Unit J - Complete.

Argon Cylinders, FLEX Diesel Generator, and FLEX The pe1for111ance criteria for the (SA WA) pump pressure at 500 gpm. Motive Gas Cylinders, Argon Cylinder has been defined and the system will meet the requirements of the order.

(Reference EC 423381 Section 3.5 and 3.33 and EC 423382 Section 3.19)

Unit 2 - Complete.

The pe1formance criteria for the Motive gas Cylinders, Argon Cylinder has been defined and the system will meet the requirements of the order.

(Reference EC 423333 sections 3.5 and 3.33 and EC 423281 Section 3.19). EC 423333, EC 423281, EC 423381, and EC 423382 are available in ePortal.

See ISEP2-6for FLEX SAWA response.

01-10 Pe1for111 radiological evaluation for Phase I vent line Units 1 and 2 - Complete.

impact on ERO response actions. The peak dose rates and 7-day integrated doses at operating stations, equipment locations, and along transit pathways required for sustai11ed operation of the HCVS have been calculated. The peak dose rates along potential operator transit Page 7 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Combined Phase 1 and Phase 2 OIP Open Items Status Phase 1 Open Items pathways external to the Reactor Building are bounded by the peak dose rate outside the FLEX storage building.

(Reference Calculation LM-0721 ). Calculation LM-0721 is available in ePortal.

Phase 2 Open Items None Phase 1 Interim Staff Evaluation Open Items Status lSE-1 Make available for NRC staff audit documentation ofa Unit 1 - Complete.

method to disable HCVS during normal operation to The system is designed to provide assurances against inadvertent operation that prevent inadvertent operation.

also minimizes actions to enable HCVS operation The new control switch HS-following an EL.AP. 057V-J 83 installed in the MCR panel JO-C689 is a key-lock switch. The swilch i:-i kept locked in "OFF" position (with key removed) to prevent inadvertent powering of the HCVS components ji*om 125 Vdc HCVS battery source.

Additionally, locked valves are used with the gas bottles to prevent inadvertent operation. (Reference EC 423381 section 3.19).

Unit 2 - Complete.

The system is designed to prevent inadvertent operation .

The new control switch HS-057V-283 installed in the MCR panel 20-C689 is a key-lock switch. The switch is kept locked in "OFF" position (with key removed) to prevent inadvertent powering of the HCVS components from 125 Vdc HCVS battel)' source.

Additionallv, locked valves Page 8 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 1 Interim Staff Evaluation Open Items Status are used with the gas bottles to prevent inadvertent operation. (Reference EC 423333 section 3. 19). EC 423333 and 423381 are available in ePortal.

ISE-2 Make available for NRC staff audit the final sizing Unit 1 - Complete.

evaluation for HCVS batteries/battery charger The HCVS batteries have been including inco1poration into FLEX DG loading sized to meet the requirements calculation. of the HCVS system and function for the initial 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the event.

(Reference Calculation LE-0128).

The FLEX diesel generator loading is acceptable and rated loading of the FLEX diesel generator will not be exceeded due to the additional HCVS loading. (Reference EC 423381 section 3.35).

Unit 2 - Complete.

The HCVS batteries have been si::.ed to 11ie e1 the require/1/ent.1 of the HCVS system and

.function for the initial 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> into the event.

(Reference Calculation LE-0128).

The FLEX diesel generator loading is acceptable and rated loading of the FLEX diesel generator will not be exceeded due to the additional HCVS loading. (Reference EC 423333 section 3.35). LE-0128 EC 423333, and EC 423381 are available in ePortal.

ISE-3 Make available for NRC staff audit an evaluation of Unit 1 - Complete.

temperature and radiological conditions to ensure that The primal)' operating station operating personnel can safely access and operate for HCVS operation is located controls and support equipment. in the Main Control Room. A remote operating station (ROS) is located in the EDG Corridor, EL. 217' (Room 313 ). The ROS lorntion and Page 9 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 1 Interim Staff Evaluation Open Items Status travel path to ROS location were evaluated for habitability and accessibility during a severe accident.

(Reference EC 423382 section 3.19).

Unit 2 - Complete.

The prima1y operating station for HCVS operation is located in the Main Control Room. A remote operating station (ROS) is located in the EDG Corridor, EL. 217' (Room 317). The ROS location and travel path to ROS location were evaluated for habitability and accessibility during a severe accident.

(Reference EC 423281 section

3. 19). EC 423281and423382 are available in ePortal.

See Note I on page 21 for ROS temperature discussion .

JSE-4 Make available for NRC staff audit analyses Unit 1 and Unit 2 - Complete.

demonstrating that HCVS has the capacity to vent the The required one percent steam/energy equivalent of one percent of capacity at the lower of licensed/rated thermal power (unless a lower value is Primary Containment just!fied), and that the suppression pool and the HCVS Pressure limit or containment together are able to absorb and reject decay heat, such design pressure is verified that.following a reactor shutdown from fitll power using Reactor Excursion and containment pressure is restored and then maintained Leak Analysis Program below the primary containment design pressure and the (RELAP ). Jn addition, primwy containment pressure limit. Modular Accident Analysis Program (MAAP) analyses are credited to verify that venting can be delayed for at least three hours and that anticipatory venting can be credited to maintain Reactor Core Isolation Cooling (RCJC) ji111ctiona/

Unit 1 (Reference EC 423382 section 3.33 and LM-709).

Unit 2 (Reference EC 423281 section 3.33 and LM-709).

Page 10 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 1 Interim Staff Evaluation Open Items Status EC 423281, EC 423382, and LM-709 are available in ePortal.

ISE-5 Make available for NRC staff audit the seismic and Unit 1 and Unit 2 - Complete.

tornado missile final design criteria for the HCVS (Reference EC 423331 section stack. 3.2, 3.5, 3.9, and 3.38 (formally known as 16-00011) and EC 423332 sectio11 3.38 (formally known as 16-00012), and EC 422831 sectio11 3.24 (formally known as13-264 )) describe seismic and tornado missile design criteria for HCVS stack. EC pkgs 423331, 423332, and 422831 are available in ePortalfor review.

lSE-6 Make available for NRC staff audit the descriptions of Unit 1 and Unit 2 - Complete.

local conditions (temperature, radiation and humidity ) HCVS is designed to mi11i111ize anticipated during ELAP and severe accident for the the impact of elevated components (valves, instrnmentation, sensors, temperatures, due to the transmitters, indicators, electronics, control devices, potential loss of ventilation, etc.) required fv r HC\IS venting including co1~fimwtio11 rndia1ion and h11111idity impact that the components are capable of pe1for111i11g their on the ability of operators to fimctions during ELAP and severe accident conditions. initiate and maintain the

.fimctionality of the HCVS.

The locations of system equipment that require operator action and the travel paths to reach the controls and indications are in mild environ 111e11ts.

Unit 1 (Reference EC 423382 section 3.19 and 3.24).

Unit 2 (Reference EC 423281 section 3. 19 and 3.24) EC 423281 and EC 423382 are available in ePortal for review.

The loss of all general area lighting, coincident with the ELAP, does not pose a threat to the operators' ability to access and operate HCVS, since self-contained emergency lights illuminate Page 11of22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 1 Interim Staff Evaluation Open Items Status the travel paths and handheld or portable lighting is available to manipulate HCVS equipment.

ISE-7 Make available for NRC staff audit documentation of Unit 1 and Unit 2 - Complete.

the HCVS nitrogen pneumatic system design including HCVS is designed to operate sizing and location. forfirst 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with installed independent pneumatic air supply, thereby eliminating the reliance on portable equipment. HCVS is also designed for multiple venting and purge cycles during the first 24-/wur period without the need to recharge pneumatic air supplies. The pneumatic air supply is located in the emergency diesel corridor.

Unit 1 (Reference EC 423381 section 3.19 and Calculation LM-0723).

Unit 2 (Rcfe rrnce EC 423333 section 3. 19 and Calculation LM-0723). EC 423333, EC 423381 and Calculation LM-0723 are available in ePortal for review.

JSE-8 Make available for NRC staff audit documentation that Unit I and Unit 2 - Complete.

demonstrates adequate communication between the This communication method is remote HCVS operation locations and HCVS decision the sa111e as accepted in Order makers during ELAP and severe accident conditions. EA-12-049. These items will be powered and remain powered using the same methods as evaluated under EA-12-049 for the period of sustained operation, which may be longer than identified for EA-12-049.

Com11111nication will be via the plant radio syste111 (f aVl1ilable. If the radio system is not available, the Plant page system can be used. The page system was modified for FLEX to include a UPS that Page 12 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 1 Interim Staff Evaluation Open Items Status can be manually aligned to repower the system.

(Reference AR 2492527-42).

AR 2492527-42 is available in ePortalfor review.

ISE-9 Provide a description of the final design of the HCVS to Unit I and Unit 2-Complete.

address hydrogen detonation and deflagration. HCVS has been designed to ensure the flammability limits of gases passing through the system are not reached. A purge gas (argo11) supply system has been provided to displace potentially flammable/ detonable mixtures of gases that may be present in the vent after system actuation. The purge gas supply system is designed for four purge cycles during the first 24-/wur period without the need to recharge.

Unit 1 (Reference EC 423381 section 3.19).

Unit 2 (Reference EC 423333 section 3.19) EC 423333 and EC 423381 are available in ePortalfor review.

!SE-JO Provide a description of the strategies for hydrogen Unit I - Complete.

control that minimizes the potential for hydrogen gas As discussed in the December migration and ingress into the reactor building or other 2015 OJP, the Limerick buildings. wetwell vent line for each unit has a dedicated HCVS flow path j/*om the wet well pe11etration to the outside with no interconnected system. The discharge point meets the guidance of "HCVS Release Point", HCVS-FAQ-04 (Reference 11 ).

Unit 2 - Complete.

(Reference EC 423281 and Calculation LM-0709 ).

EC 423281 and Calculation LM-0709 are available in ePortal f or review.

/SE-I I Make available for NRC staff audit documentation of a Unit I- Complete.

seismic qualification evaluation of HCVS compo11ents.

Page 13 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 1 Interim Staff Evaluation Open Items Status Seismic documentation has been provided EC 423381, Section 3.4, EC 423382, Section 3.4, and AR 2492527-97.

Unit 2 - Complete.

Seismic documentation has been provided in Reference EC 423331 section 3.4 and 3.38, EC 423333 section 3.4, 3.38 and attachment 45, and 617568 section 3.2. EC 423331, EC 423333, EC 617568, EC 423381, EC 423382, and AR 2492527-97 are available in ePortalfor review.

ISE-12 Make available for NRC staff audit descriptions of all Unit I - Complete.

instrumentation and controls (existing and planned) EC 423381 installed and necessmy to implement this order including qualified the following qualification methods. components in the MCR and in the plant:

valve position indicating lights, power key-locked switch, temperature indicator displays, radiation monitoring system consisting of an element local to the HCVS vent pipe, and a man itor.

(Reference EC 423381 section 3.19 and 3.36 ).

Existing pressure instrument Pl-042-170-1 will be used to monitor containment pressure in the d1:vwell. The transmitter (PT-042-170) has been replaced with an RC 1.97 qualified component to ensure this will remain ji111ctioning during the event. See EC 423381 for replacement and EC 423382 section 3.19 for qualification of the component.

Unit 2 - Complete.

EC 423333 installed and qualified the follmvin f?

Page 14 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 1 Interim Staff Evaluation Open Items Status components in the MCR and in the plant:

valve position indicating lights, power key-locked switch, temperature indicator displays, radiation monitoring system consisting of an element local to the HCVS vent pipe, and a monitor.

(Reference EC 423333 section 3.19 and 3.36)

Existing pressure instrument Pl-042-270-1 will be used to monitor containment pressure in the d1)1well. See EC 617568 section 3.2 for qualification of the component.

EC 423333, EC 617568, EC 423381 and EC 423382 are available in ePortalfor review.

ISE-13 Make available for NRC staff audit the procedures for Unit I and Unit 2 - Complete.

HCVS operation. Reference the following proced11res.

SAMP-1: RPV Control SAM P-2: Containment and Radioactivity Release Control T-101: RPV Control T-102: Prim{//)' Containment Control SPIT, SPIL, PC!P, DW!T, PC/H T-341: Prima1y Containment Venting Via Hardened Containment Vent System.

These procedures are in ePortal for review.

Phase 2 Interim Staff Evaluation Open Items Status ISEP2-l Licensee to demonstrate that the HCVS components Unit 1 and Unit 2 - Complete.

meeting reasonable protection from tornado missiles is Per Drawing HBD-842-01 ,

at least 30feet above the highest grade within 300 HCVS pipe leaves the yards. protected structure more than 120 feet above grade elevation, which is 217 feet MSL, as indicated on site Page 15 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 2 Interim Staff Evaluation Open Items Status topographical drawing C-0062 that shows grade elevation referenced to MSL within 300 yards of the HCVS components evaluated.

ISEP2 -2 Licensee to confirm through analysis the temperature Unit 1 and Unit 2 - Complete.

and radiological conditions to ensure that operating Actio11s taken within the first personnel can safely access and operate co11trols and hour (prior to start of core support equipment. damage) from the start of the ELAP are acceptable from an environmental and radiological perspective without further evaluatio11.

Actions within the MCR are acceptable for the e11tire period of Sustained Operation per HCVS-FAQ -01.

Actions within the Reactor Building a11d between I a11d 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />, evaluation of expected temperatures and dose rates has been pe1for111ed and determined them to be acceptable. (Reference EC 622673, and calculations LM-0721 and LM-0725).

For locations outside the Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days, Limerick pe1.formed evaluations for the temperature and radiological conditions for the equipment and deployment locations, including ingress/egress paths and determined them to be acceptable. (Refere11ce EC 622673, and calculations LM-0721 and LM-0725). EC 622673, LM-0721 and LM-0725 are available in ePortal for review.

See Note 1 on page 21 for ROS temJJerature discussion .

Page 16 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 2 Interim Staff Evaluation Open Items Status ISEP2-3 Licensee to evaluate the SA WA equipment and Unit I and Unit 2 - Complete.

controls, as well as the ingress and egress paths for the Equipment and Controls expected severe accident conditions (temperature, humidity, radiation) for the sustained operating period. Plant instrumentation for SA WA/SA WM that is qualified to RG 1.97 or equivalent is considered qualified for the sustained operating period without further evaluation.

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

The following additional equipment pe1forming an active SA WA/SA WM ji1nction is considered:

SA WA/SA WM flow i11st m111en1 SA WA/SA WM/FLEX pump SA WA/SA WM/FLEX generator Active valves in SAWAflow path.

Ingress and Egress For loattions outside the Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days when SA WA is being utili~ed, Limerick pe1for111ed evaluations of expected temperatures, humidity and the dose rates and determined them to be acceptable. (Reference EC 622673, and calculations LM-0721 and LM-0725).

EC 622673, LM-0721 and LM-0725 are available in ePortal for review.

Page 17 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 2 Interim Staff Evaluation Open Items Status ISEP2-4 Licensee to demonstrate that containment failure as a Unit 1 and Unit 2 - Complete.

result of overpressure can be prevented without a The wetwell vent has been drywell vent during severe accident conditions. designed and installed to meet NEJ 13-02 Rev 1 guidance, which will ensure that it is adequately sized to prevent containment ove11Jressure under severe accident conditions.

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

LGS will follmv the guidance (flow rate and timing) for SA WA/SA WM described in BWROG-TP-15-008 and BWROG-TP-15-01 I.These documents have been posted to the ePortal for NRC staff review. The wetwell vent will be opened prior to exceeding the PCPL value rf 60 PS!G.

Therefore, containment over pressuri~ation is prevented without the need for a drywell vent.

ISEP2-5 Licensee shall demonstrate how the plant is bounded Unit 1 and Unit 2 - Complete.

by the reference plant onalysis that shows the SA WM Using Figure 2.1. C ji*om the strategy is succes:ijitl in making it unlikely that a combined Phases I and 2 OJ P, d1ywell vent is needed. compare the reference plant parameters to the plant specific parameters.

Reference LGS Plant Torus Suppression freeboard Pool volume is free board 525,000 volume is gallons /47,670ft3

(/,/04,572 Rallons)

SAWAflow SAWAflow is is 500 GPM 500 GPM at at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> Page 18 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 2 Interim Staff Evaluation Open Items Status followed by followed by JOO GPM IOOGPM from 12 from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to hours to 168 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> hours The above parameters for LGS compared to the reference plant that determine success of the SA WM strategy demonstrate that the reference plant values are bounding.

Therefore, the SA WM strategy implemented at LGS makes it unlikely that a DW vent is needed to prevent containment ove1pressure related failure .

ISEP2-6 Licensee to demonstrate that there is adequate Unit 1 and Unit 2 -Complete.

communication between the MCR and the operator at This communication method is the FLEX pump during severe accident conditions. the same as accepted in Order EA-12-049. These items will be powered and remain powered using the same methods as evaluated under EA-12-049.for the period of sustained operation, which may be longer than identified for EA-12-049.

Communication will be via the plant radio system if available.

lf the radio system is not available, the Plant page system can be used. The page system was modified for FLEX to include a UPS that can be manually aligned to repower the system. (Reference AR 2492527-42) 1SEP2-7 Licensee to demonstrate the SA WM flow Unit I and Unit 2 - Complete.

instrumentation qualification for the expected For locations outside the environmental conditions Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days when SA WA is being utilized, limerick Generating Station pe1for111ed evaluation of expected temperatures, humidity and the Page 19 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 Phase 2 Interim Staff Evaluation Open Items Status dose rates and determined them to be acceptable.

(Reference EC 622673).

SAWA Pump Expected Flow SAWA Instrument Parameter Qualification Ran!(e 37 to 1246 100 to 500 GPM GPM 32 to 140 °F 32 to 95 °F fluid fluid temperature temperature 14 to 122 °F 0 to JOO °F lnstru men t Ambient air Electronics121 temperature 275 PSI 239.7 PSI 111axi111 um llWX I 111U111 121 Below I 4 °F, the LCD may become sluggish or unresponsive; however, it will continue to measure and

.function to at least -4 °F.

(Reference MS2500-DataSheet).

MS2500-DataSheet and EC 622673 are available in ePortal f or review.

Note 1:

For the location of the ROS in the DG corridor, there is a maximum expected temperature of 121 °F. This temperature is expected to occur due to a non-safety related heating steam pipe rupturing during a seismic event. To mitigate this issue, the heating steam pipe was analyzed and additional supports have been installed to ensure the piping will not rupture (EC 423333 and EC 423381 ). There are no additional process fluid piping or heat generating equipment that would add significant heat to this area. Therefore, the area will then be at outside ambient conditions which does not normally exceed 100 °F.

The performance validation for T-341 to align the HCVS for operation determined the longest duration of 16 minutes in the EOG corridor would be required to align the system.

Activation of the system included opening the argon and air bottles and repositioning a three-way valve. This would be the longest duration of any operator at the ROS during the event. If required, operating personnel working in high temperature areas will be protected using SA-AA-111, Heat Stress Control. With the use of SA-AA-111 heat stress controls, it is reasonable to assume the operator actions required to implement the HCVS and Page 20 of 22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018 SAWA/SAWM strategies can be accomplished. SA-AA-111 and the validation study are available in ePortal.

7 Interim Staff Evaluation Impacts There are no potential impacts to the Interim Staff Evaluations 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 attachment.

1. Limerick Generating Station, Units 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
2. NRC Order Number EA-13-109, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions" dated June 6, 2013
3. NEI 13-02, "Industry Guidance for Compliance with NRC Order EA-13-109, 'To Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision 1, dated April 2015
4. NRC Interim Staff Guidance JLD-ISG-2013-02, "Compliance with Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision 0, dated November 2013 (Accession No. ML133048836)
5. NRC Endorsement of Industry "Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Template (EA-13-109) Rev O" (Accession No. ML14128A219)
6. NRC Interim Staff Guidance JLD-ISG-2015-01, "Compliance with Phase 2 of Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision O, dated April 2015 (Accession No. ML15104A118)
7. 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
8. Exelon Generation Company, LLC, First Six-Month Status Report for 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 17, 2014 Page 21of22

Limerick Generating Station, Unit 2 Eighth Six-Month Status Report for the Implementation of HCVS Phases 1 and 2 June 29, 2018

9. Exelon Generation Company, LLC, Second Six-Month Status Report for 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
10. Missile Evaluation for HCVS Components 30 feet Above Grade, HCVS-WP-04, Revision 0(ML15244A923), August 8, 2015
11. HCVS Release Point, HCVS-FAQ-04, Revision 1, (ML14120A289), April 14, 2014
12. 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
13. Limerick Generating Station Units 1 and 2 - Interim Staff Evaluation Relating To Overall Integrated Plan In Response To Phase 2 of Order EA-13-109 (Severe Accident Capable Hardened Vents) (CAC NOS. MF4418 and MF4419), dated August 2, 2016
14. 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) dated December 15, 2016
15. Sixth 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, 2017
16. Seventh 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 December 15, 2017 Page 22 of 22
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