RS-16-236, 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 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 Operation Under Severe.

ML16349A033
Person / Time
Site:	Nine Mile Point
Issue date:	12/14/2016
From:	David Helker Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-109, RS-16-236
Download: ML16349A033 (48)

Text

Exelon Generation , .

Order No. EA-13-109 RS-16-236 December 14, 2016 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Nine Mile Point Nuclear Station, Units 1 and 2 Renewed Facility Operating License Nos. DPR-63 and DPR-69 NRG Docket Nos. 50-220 and 50-410

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. NRG 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. 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 0, dated November 14, 2013

3. NRG 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 27, 2014

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 (FLL-14-035)

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-15-153)

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 December 14, 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-15-302)

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-16-111)

11. NRC letter to Exelon Generation Company, LLC, Nine Mile Point Nuclear Station, Unit 1 -

Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 1 of Order EA-13-109 (Severe Accident Capable Hardened Vents) (TAC No. MF4481), dated March 26, 2015

12. NRC letter to Exelon Generation Company, LLC, Nine Mile Point Nuclear Station, Unit 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 No. MF4482), dated February 11, 2015

13. NRC letter to Exelon Generation Company, LLC, Nine Mile Point Nuclear Station, Unit 1 -

Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 2 of Order EA-13-109 (Severe Accident Capable Hardened Vents) (TAC No. MF4481), dated August 30, 2016

14. NRC letter to Exelon Generation Company, LLC, Nine Mile Point Nuclear Station, Unit 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 No. MF4482), dated August 25, 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 provided the EGC initial response regarding reliable hardened containment vents capable of operation under severe accident conditions. Reference 6 provided the Nine Mile Point Nuclear Station, Units 1 and 2, 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 Nine Mile Point Nuclear Station. Reference 9 provided the Nine Mile Point Nuclear Station, Units 1 and 2, Phase 1 updated and Phase 2 OIP pursuant to Section

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 December 14, 2016 Page 3 IV, Conditions D.2 and D.3 of Reference 1. Reference 1O provided the fourth six-month status reports pursuant to Section IV, Condition D.3 of Reference 1 for Nine Mile Point Nuclear Station.

The purpose of this letter is to provide the fifth six-month update reports 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 Nine Mile Point Nuclear Station, Units 1 and 2.

The enclosed reports provide 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 reports also address the NRC Interim Staff Evaluation open items contained in References 11, 12, 13, and 14.

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 141h day of December 2016.

Respectfully submitted, David P. Helker Manager - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosures:

1. Nine Mile Point Nuclear Station, Unit 1 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

2. Nine Mile Point Nuclear Station, Unit 2 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 - Nine Mile Point Nuclear Station NRC Project Manager, NRA - Nine Mile Point Nuclear Station Mr. Raj Auluck, NRR/JLD/TSD/JCBB, NRC Mr. Brian E. Lee, NRR/JLD/JCBB, NRC Mr. Jason C. Paige, NRR/JLD/JOMB, NRC

Enclosure 1 Nine Mile Point Nuclear Station, Unit 1 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 1 Nine Mile Point Nuclear Station, Unit 1 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 Nine Mile Point Unit 1 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 six month status report updates the milestone accomplishments based on the combined Phases 1 and 2 Overall Integrated Plan dated December 15, 2015 (Reference 7) and last updated on June 30, 2016 (Reference 9).

Nine Mile Point Unit 1 developed an updated and combined Phases 1 and 2 Overall Integrated Plan (Reference 7 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 combined Phases 1 and 2 Overall Integrated Plan and the last six month update, 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 last six-month update was submitted under Reference 9, and are current as of December 2, 2016.

• Fifth Six-Month Update (complete with this submittal)

Page 1 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 3 Milestone Schedule Status The following provides an update to the Part 5 Milestone Schedule of the Overall Integrated Plan. It provides the activity status of each item, and whether the expected completion date has changed. The dates are planning dates subject to change as design and implementation details are developed. The revised Design Engineering Complete date shown below does not impact the order implementation date.

NMP1 - Phase 1 Specific Milestone Schedule Target Activity Milestone Completion Comments Status Date Hold preliminary/conceptual design November Complete meeting 2013 Submit Overall Integrated Implementation June 2014 Complete Plan Submit 6 Month Status Report December Complete 2014 Submit 6 Month Status Report June 2015 Complete Submit 6 Month Status Report December Complete Simultaneous with 2015 Phase 2 OIP Submit Combined Phase 1 & 2 Six-Month June 2016 Complete Status Report Design Engineering Complete J!:!ly 29~0 Started Design Package issued February January 2016 and revised 2017 pkg . issued June 2016 to capture lessons learned from NMP2. Additional Design Package changes in progress.

Submit Combined Phase 1 & 2 Six-Month December Complete Status Report 2016 with this submittal Maintenance and Operation Procedure February Started Changes Developed, Training Complete 2017 Implementation Outage April 2017 Not Started Procedure Changes Active, Walk-Through April 2017 Not Started Demonstration/Functional Test Submit Completion Report June 2019 Not Started Page 2 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 NMP1 - Phase 2 Specific Milestone Schedule Target Activity Milestone Completion Comments Status Date Submit Overall Integrated Implementation December Complete Simultaneous with Plan 2015 Phase 1 Updated OIP Hold preliminary/conceptual design meeting June 2015 Complete Submit 6 Month Status Report June 2016 Complete Submit 6 Month Status Report December Complete 2016 with this submittal Submit 6 Month Status Report June 2017 Not Started Submit 6 Month Status Report December Not 2017 Started Submit 6 Month Status Report June 2018 Not Started Submit 6 Month Status Report December Not 2018 Started Design Engineering Complete April 2018 Not Started Maintenance and Operation Procedure February Not Changes Developed , Training Complete 2019 Started Implementation Outage April 2019 Not Started Procedure Changes Active, Walk-Through April 2019 Not Demonstration/Functional Test Started Submit Completion Report June 2019 Not Started 4 Changes to Compliance Method There are no changes to the compliance method as documented in the combined Phases 1 and 2 Overall Integrated Plan (Reference 7).

5 Need for Relief/Relaxation and Basis for the Relief/Relaxation Nine Mile Point Unit 1 expects to comply with the order implementation date and no relief/relaxation is required at this time.

Page 3 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 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 Attachment 7 of the combined Phases 1 and 2 Overall Integrated Plan, the Reference 6 Interim Staff Evaluation (ISE) for Phase 1 and the Reference 10 ISE for Phase 2, and the status of each item.

Open Phase 1 Open Items from OIP Status Item

1. Perform final sizing evaluation for Deleted (closed to ISE open item HCVS batteries and battery charger number 7 below) and include in FLEX DG loading calculation.

2. Perform final vent capacity calculation Deleted (closed to ISE open item for the Torus HCVS piping confirming number 2 below) 1 % minimum capacity.

3. Perform final sizing evaluation for Deleted (closed to ISE open item pneumatic Nitrogen (N2) supply. number 8 below)

4. Perform confirmatory environmental Deleted (closed to ISE open item condition evaluation for the Turbine numbers 6 and 11 below)

Building in the vicinity of the Remote Operating Station (ROS) and HCVS dedicated pneumatic supply and batteries.

5. State which approach or combination Deleted (closed to ISE open item of approaches the plant determines is number 3 below) necessary to address the control of combustible gases downstream of the HCVS control valve.

6. Complete evaluation for Deleted (closed to ISE open item environmental/seismic qualification of numbers 9 and 11 below)

HCVS components.

7. Complete evaluation for Deleted (closed to ISE open item environmental conditions and confirm number 6 below) the travel path accessibility.

8. Perform radiological evaluation for Started Phase 1 vent line impact on ERO response actions.

Page 4 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Item Status (ISE) Open Items 1 Make available Seismic Design of HCVS stack Complete for NRC staff The HCVS vent piping system has been audit the seismic evaluated to Seismic Category I and tornado requirements in pipe stress calculations missile final S22.4-201.1 P002 and S22.4-201.13P003 design criteria for consistent with the plant's seismic design the HCVS stack.

basis to comply with NEI 13-02, Section 5.2 seismic design guidance. Per NRC Letter, May 9, 2014 "

Subject:

Screening and Prioritization Results Regarding Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Seismic Hazard Re-Evaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident", the NRC concluded that NMP1 "screened out" of performing the seismic risk evaluation as part of the HCVS seismic analysis. Therefore, use of current licensing basis and design basis seismic information (i.e., response spectra) is considered acceptable for the BOB analysis of the HCVS piping system at NMP1. The above referenced pipe stress calculations are available for NRC review in the ePortal.

Missile Protection of the HCVS stack NEI 13-02, Section 5.1.1 .6 requires that missile impacts are to be considered for portions of the HCVS. The Nuclear Energy Institute (NEI) issued a white paper HCVS-WP-04, endorsed by the NRC, which provides a risk-informed approach to evaluate the threat posed to exposed portions of the HCVS by wind-borne missiles.

The white paper concludes that the HCVS is unlikely to be damaged in a manner that prevents containment venting by wind-generated missiles coincident with an ELAP or LUHS, for plants that are enveloped by the assumptions in the white paper.

Page 5 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Item Status (ISE) Open Items A NMP1 specific missile evaluation is documented in the Engineering Change Package (ECP) consistent with HCVS-WP-

04. The conclusion of the evaluation is that NMP1 meets all of the tornado missile assumptions identified in HCVS-WP-004 and as such, supplementary protection is not required for the HCVS piping and components. The ECP missile evaluation is available in the ePortal for NRC review.

2 Make available The HCVS is sized to provide sufficient Complete for NRC staff venting capacity to prevent a long-term audit analyses overpressure failure of the containment by demonstrating keeping the containment pressure below the that HCVS has containment design pressure and the primary the capacity to containment pressure limit. The HCVS has vent the been demonstrated by calculation 822.4-steam/energy 201.13F004 to have the capacity to vent the equivalent of one steam/energy equivalent of 1 percent of percent of licensed/rated thermal power. The calculation licensed/rated indicates that a vent capacity of thermal power approximately 68,300 lbm/hour of saturated (unless a lower steam at the primary containment design value is justified), pressure is required. The results of this and that the calculation show that the capacity of the suppression pool HCVS exceeds this value.

and the HCVS The suppression pool thermal capacity must together are able be sufficient to absorb the decay heat to absorb and generated during at least the first 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> reject decay heat, following reactor shutdown. The total decay such that heat available to the suppression pool for the following a first 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> following reactor shutdown, reactor shutdown when starting at 102% reactor thermal power, from full power is 2.91 OE8 BTU; and the suppression pool containment thermal capacity, i.e., its capacity to absorb pressure is energy, is 6.299E8 BTU. Therefore, there is restored and then sufficient suppression pool capacity to absorb maintained below the decay heat during the first 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> the primary following reactor shutdown, and the EA containment 109, Attachment 2, Requirement 1.21 and design pressure NEI 13-02, Section 4.1.1 are satisfied.

and the primary The calculations supportinQ the above Page 6 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Status Item (ISE) Open Items containment response are available for NRG review in the pressure limit. ePortal.

3 Provide a As discussed in the December 2015 OIP Complete description of the submittal, the NMP1 design will use an Argon final design of the purge system to prevent the possibility of HCVS to address hydrogen detonation and deflagration. The hydrogen argon purge system design is illustrated on detonation and Piping and Instrumentation Drawing C-def lag ration . 18014-C, Sht. 7, and is available for NRG review in the ePortal. The argon purge system was sized in calculation S22.4-201.13F001 which is on the ePortal.

4 Make available At NMP1 , the primary operating station for Complete for N RC staff HCVS operation is located in the Auxiliary audit Control Room. A HCVS remote operating documentation station (ROS) is located in the turbine that demonstrates building . The location was evaluated for adequate habitability and accessibility during a severe communication accident. Onsite communications will be between the performed using either the installed sound remote HCVS powered headset system or the 450 MHz operation radios in the talk around mode, or a locations and combination thereof. A sound powered phone HCVS decision jack is available near the ROS to makers during communicate with the rest of the plant.

ELAP and severe Offsite communications will utilize fixed accident satellite phones in the Control Room and conditions.

Technical Support Center (TSC) . Both locations also have portable satellite phones staged.

Communications protocol for beyond design basis events are documented in CC-NM-118 and procedure N1-0P-51 and are available for NRG review in the ePortal.

These communication methods are consistent with FLEX communication practices at NMP1 and have been previously reviewed by the staff as documented in a communications safety assessment regarding NTTF Rec 9.3 Communications for Page 7 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Item Status (ISE) Open Items NMP (ML13100A236).

5 Provide a P&IDs C18014C, Sheets 1 and 7 are Complete description of the available to the NRC for review on the strategies for ePortal. The P&IDs combined with the hydrogen control following system description provides a that minimizes the summary of the system design intended to potential for minimize the potential for hydrogen gas hydrogen gas migration and ingress into the reactor migration and building or other buildings:

ingress into the The new HCVS wetwell pipe has a dedicated reactor building or HCVS flowpath from the wetwell penetration other buildings.

PCIVs to the outside with no interconnected downstream piping. The HCVS discharges the effluent to a release point above main plant structures. The new HCVS vent interfaces with lines 201.1-20-LT (upstream of PCIVs IV-201-16 and IV-201-17) and 201.1-3-LT (upstream of PCIV IV-201 .2-33 and IV-201.2-06) of the Containment System.

Line 201.1-20-LT is utilized for supplying nitrogen to the torus through isolation valves IV-201-16 and IV-201-17 during primary containment inerting. Similarly, the containment purge fan takes suction through this flow path when de-inerting containment.

IV-201-16 and IV-201-17 are normally closed and automatically close upon receipt of a containment isolation signal from the Reactor Protection System or a high radiation signal from the Off-Gas System monitors.

Line 201.1-3-LT provides nitrogen makeup to the torus through isolation valves IV-201.2-33 and IV-201.2-06 during normal operation. IV-201.2-33 and IV-201.2-06 are normally closed and automatically close upon receipt of a containment isolation signal from the Reactor Protection System or a loss of motive air supply.

The new HCVS vent will be normally isolated from the Containment System by two new normally closed PCIVs (IV-201.13-74 and IV-Page 8 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Item Status (ISE) Open Items 201.13-71) and will not impact the operation of these interfacing systems. The new HCVS piping is designed as an independent, isolable branch off of Line 201.1-20-LT.

There are no branch lines downstream of the HCVS vent piping PCIVs (IV-201.13-71 and IV-201.13-74), which interface with existing plant systems and there is no potential for cross flow from the HCVS, thereby meeting the requirements of NEI 13-02, Section 1.2.3.

Therefore, valves IV-201.2-33, IV-201.2-06, IV-201-16 and IV-201-17 are not considered boundary valves. These valves are exposed to the containment atmosphere, as a result of the original plant design, independent of the addition of HCVS.

6 Make available An assessment of Operator access to HCVS Complete for NRC staff equipment was performed and documented audit an in the Design Consideration Section (DCS) of evaluation of Engineering Change Package ECP temperature and 000086 which has been loaded on the radiological ePortal. The assessment evaluated the conditions to temperature and radiological conditions of all ensure that areas that will be needed to be accessed by operating plant Operators in order to initiate and personnel can operate the HCVS during a beyond design safely access and basis event. The assessment provides the operate controls expected temperature and radiological and support conditions in each area documented in equipment. tabular form in the DCS. The assessment concludes that during the 7 days of sustained operation during a beyond design basis event the predicted environmental and radiological conditions will be acceptable for the operators to gain access to areas required for HCVS operation in the primary and remote operating stations.

7 Make available The new battery selected is a sixty (60) cell Complete for NRC staff GNB battery with the battery cells connected audit the final in series to create 125VDC nominal voltage.

sizing evaluation The battery is a Valve Regulated Lead Acid forHCVS (VRLA) type rated for 104 ampere-hours.

Page 9 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Item Status (ISE) Open Items batteries/battery The battery is selected in accordance with charger including IEEE-485. The Battery Sizing Requirements incorporation into indicates that based on 1.5 ampere loading FLEX DG loading requirements for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> duty period, a calculation. minimum of a sixty (60) cell, 55 ampere-hours battery is required to bound the required battery duty cycle and end-of-cycle battery terminal voltage requirements. The selected battery capacity of 104 ampere-hours is more than the minimum required 55 ampere-hours battery capacity. Therefore, the selected battery is adequate.

The battery charger is rated for 130 volts nominal DC output voltage, 10 amperes nominal DC output current, 120 volts AC input voltage and a current limit adjustment range of 50% - 120%.

The HCVS loads may also be powered via 125 voe battery board 12 which is downstream of the station battery charger 12 (DC side). The FLEX DG sizing calc.

600VACDGES-FLEX-BDB was already sized to accommodate the station battery charger 12 full load rating (AC side). Additionally, the HCVS loads will be powered by FLEX portable power sources at T=:: 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> when the station battery would have been fully charged and load shedding would have been completed during ELAP. Therefore, there will be no impact on the FLEX DG loading calculation 600VACDGES-FLEX-BDB. A minor revision to the FLEX portable battery charger equipment sizing calculation 125VDCSCES-FLEX-BDB was completed to address the addition of the HCVS loads. The calculation concluded that the HCVS panel load addition of 1.5 amperes DC is negligible and still within the 400 ampere rating of the portable battery charger BC-BOB.

The battery/battery charger sizing requirements evaluation and the minor revision to calculation 125VDCSCES-FLEX-Page 10 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Item Status (ISE) Open Items BOB are in the ePortal for NRC review.

8 Make available As discussed in the December 2015 OIP Complete for NRC staff submittal, the NMP1 design will use a audit nitrogen bottle station to supply motive force documentation of to the HCVS isolation valves. The bottle the HCVS station will be located in a readily accessible nitrogen protected area in the turbine building. The pneumatic system nitrogen supply system design is illustrated design including on Piping and Instrumentation Drawing C-sizing and 18014-C, Sht. 7, and is available for NRC location. review in the ePortal.

A calculation was completed to determine the required pneumatic supply storage volume and supply pressure required to operate the HCVS isolation valves (IV-201.13-71 and IV-201.13-74) for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following a loss of normal pneumatic supplies during an ELAP.

Calculation S22.4-201.13M002 is available for NRC review in the ePortal.

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

10 Make available Description of Existing Instrumentation: Complete for NRC staff In the Phases 1 and 2 combined HCVS OIP, audit descriptions Part 2: Key Venting Parameters section, both of all drywell pressure, torus pressure and torus instrumentation level are listed as key parameters. Other Part and controls 2 OIP sections only list drywell pressure and (existing and torus pool level as key parameters. In Part 3 planned) of the OIP, drywall pressure and suppression necessary to pool level are stated as the key parameters implement this for SAWM operations. The following order including discussion has been revised since the June qualification 2016 six-month update to clarify what key methods.

parameters are used for HCVS initiation and Page 11 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Item Status (ISE) Open Items cycling for Phases 1 and 2.

Existing control room indications for wetwell (suppression chamber) pressure and suppression pool (primary containment) water level are used for HCVS venting operation. Operation of the HCVS will be based on guidance in the EOPs and SAPs and will follow the primary containment pressure limit (PCPL) curves contained in these procedures. The PCPL curves use suppression chamber pressure vs. primary containment water level parameters to determine when to vent containment.

Therefore, containment wetwell pressure indication is preferred to determine the need ,

timing and effectiveness of the venting operation following a BOBEE, in order to ensure that containment pressure does not exceed the PCPL.

Existing control room indication for wetwell pressure, shown on Pl-201.2-595A (Channel

12) and Pl-201 .2-594A (Channel 11 ), will be used for this purpose. These indicators receive pressure signals from pressure transmitters PT-201.2-595 and PT-201 .2-594, respectively. These pressure transmitters sense the torus pressure from a penetration at the top of the torus and therefore will not be impacted by high water levels.

Orywell pressure instrumentation may also be referenced during the event. Containment pressure is displayed on indicator Pl-201.2-483A (Channel 12) and Pl-201.2-484A (Channel 11 ). These indicators receive pressure signals from pressure transmitters PT-201.2-483 and PT-201.2-484, respectively. Wetwell level indication is needed to determine that the wetwell vent path is preserved. Wetwell level is displayed on indicator Ll-201 .2-5950 (Channel 12) and Ll-201.2-594C (Channel 11 ). Ll-201.2-5950 Page 12 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Item Status (ISE) Open Items receives signals from PT-201.2-595 and PT-201.2-596 while Ll-201.2-594C receives signals from PT-201.2-594 and PT-201.2-680. As indicated in the OIP, LI 58-05A (LT 58-05) can also be used to monitor torus level and Pl 201.2-106A (PT 201.2-106) can also be used to monitor drywell pressure.

The pressure and level indicators and related transmitters are all Safety Related, Regulatory Guide 1.97 compliant components. Channel 12 is the FLEX diesel power backed loop, and Channel 11 can be powered as an alternate strategy.

Description of New Instrumentation:

The l&C scope for the HCVS is to display the following and to control the SOVs associated with the new primary containment isolation valves.

• HCVS Isolation Valve Position Indication (POS)

• Temperature and Radiation of the HCVS Pipe (POS)

• Radiation of the HCVS Pipe (ROS)

• HCVS Purge System Supply Pressure (POS and ROS)

• HCVS Battery Voltage (ROS)

The ROS panel serves as the main power distribution for all l&C components and will contain local indicators to display HCVS battery voltage, radiation, and purge gas supply pressure. The POS panel provides all other indication except HCVS battery voltage and allows for the control of the HCVS SOVs via key lock switches.

A detailed description of new I &C components including qualification methods is included in the Engineering Change Package and is available on the ePortal for Page 13 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Interim Open Staff Evaluation Description Item Status (ISE) Open Items NRC review.

11 Make available Started 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.

Phase 2 OIP and ISE Open Items Open Phase 2 OIP Open Item Description Status Item 1 Perform radiological evaluation to determine the SAWA flow Started control point location.

Open Phase 2 Interim Staff Evaluation (ISE) Open Item Description Status Item Licensee to confirm through analysis the temperature and 1 Started radiological conditions to ensure that operating personnel can Page 14 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 safely access and operate controls and support equipment (ISE Section 3.3.2.1 )

Licensee to evaluate the SAWA equipment and controls, as well as ingress and egress paths for the expected severe accident 2 Not Started conditions (temperature, humidity, radiation) for the sustained operating period (ISE Section 3.3.2.3).

Licensee to demonstrate how instrumentation and equipment being used for SAWA and supporting equipment is capable to 3 Not Started perform for the sustained operating period under the expected temperature and radioloqical conditions (ISE Section 3.3.2.3).

Licensee to demonstrate that containment failure as a result of 4 overpressure can be prevented without a drywell vent during Not Started severe accident conditions (I SE Section 3.3.3).

Licensee to demonstrate how the plant is bounded by the reference plant analysis that shows the SAWM strategy is 5 Not Started successful in making it unlikely that a drywall vent is needed (ISE Section 3.3.3.1 ).

Licensee to demonstrate that there is adequate communication 6 between the MCR and the operator at the FLEX manual valve Not Started during severe accident conditions (ISE Section 3.3.3.4).

Licensee to demonstrate the SAWM flow instrumentation 7 qualification for the expected environmental conditions (ISE Not Started Section 3.3.3.4).

Page 15 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 7 Interim Staff Evaluation (ISE) Impacts As described above in the response to the ISE Open Item 10, the existing containment instrumentation credited has been changed to credit torus pressure indication in lieu of drywell pressure indication, although drywell pressure indication will also be available.

Secondly, in the Reference 10 HCVS Phase 2 ISE, sections 3.1.2 and 3.3.2.1, the NRC staff makes reference to HCVS power supplies based on information provided in the Reference 7 combined Phases 1 and 2 OIP. Changes to the HCVS power supply design described in the OIP have been made in the final design that necessitates a revision to the OIP discussion. Below is a revision to each OIP section impacted which shows the changes made to the HCVS power supply summaries.

OIP Page 11 of 64, third bullet under the time constraint discussion:

24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, connect back-up power. The HCVS battery is calculated to last a minimum of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The HCVS components will be able to be re-powered directly from the 125V DC Battery Board #12 which will be re-powered from a portable diesel generator (DG) put in place for FLEX. The DG will be staged and placed in service within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (Reference 1) and therefore will be available prior to being required. In the event that the DG is not available, a local 120 VAC connection will allow a small portable generator staged outside of the turbine building to be connected to the HCVS battery charger to provide power.

OIP Page 14 of 64, under "Power and Pneumatic Supply Sources":

All electrical power required for operation of HCVS components will be provided by a dedicated HCVS battery charger and battery. The HCVS battery has a minimum capacity capable of providing power to the HCVS loads for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> without recharging.

A final confirmatory evaluation has been completed as part of the detailed design process. The HCVS battery charger provided requires a 120 V AC supply. This will be fed by a 120/240 V AC rated lighting panel during normal plant operation. After the initial 24-hour period, the system can be aligned to 125 V DC Battery Board 12, which will be re-powered by a diesel generator as part of the FLEX response. In addition, a connection point that utilizes standard 120 VAC electrical connections will be provided for a portable generator for sustained operation of the HCVS.

OIP Page 21 of 64, 4th paragraph under Greater than 24 Hour Coping Detail:

The HCVS battery and battery charger will also be installed in the Turbine Building ROS area. The HCVS battery has a capacity sufficient for 24-hour operation. The normal power supply to the HCVS controls and instruments will be provided by a 120/240 V AC rated lighting panel via the HCVS battery charger. The #12 Station Battery Bus, which in turn is re-powered by a 600 VAC portable diesel generator connected to the # 12 Station Battery Charger as part of the FLEX response, can be aligned to the HCVS loads after the dedicated HCVS battery has completely discharged. A design change to install the portable diesel generator external connection points to this bus has been completed in support of EA-12-049 (Reference 1). In the event that power is not restored to the bus, a local 120 V AC connection to the HCVS battery charger will allow the HCVS battery charger to receive power from a small portable generator. Actions to Page 16 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 replenish the electrical supply include refueling the DG or connecting and refueling a small portable generator.

OIP Page 26 of 64, 3rd bullet under general description of venting actions using portable equipment:

Establishing temporary power to repower the battery charger. Option 1 is to connect the FLEX DG to Station Battery Charger #12, which provides power to Station Battery Bus

1. 12 that in turn powers the HCVS components. Option 1 would be completed as part of the FLEX response strategy and occurs to the south and inside the NMP Turbine Building. Option 2, to be taken if the FLEX DG cannot be connected to the Station Battery Charger #12, is to connect a small portable generator to the HCVS battery charger. Option 2 would be taken locally at the HCVS ROS Area. Either of these actions will also require the generators to be refueled. A one line diagram of the electrical system to be installed is included in sketch 1A.

OIP Sketch 1A: This sketch is out-of-date. The attached ECP-13-000086-MU-039 F45940C-002 provides an updated electrical layout of the HCVS.

8 References The following references support the updates to the combined Phases 1 and 2 Overall Integrated Plan described in this enclosure.

1. Nine Mile Point Unit 1's 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 27, 2014.

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 Evaluation "Nine Mile Point Nuclear Station, Unit 1 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 1 of the Order EA-13-109 (Severe Accident Capable Hardened Vents (TAC NO. MF4481)", dated March 26, 2015.

7. Nine Mile Point Unit 1's Combined Phases 1 and 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Page 17 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109)," dated December 15, 2015.

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

Revision 0, dated April 2015 (Accession No. ML15104A118).

9. Nine Mile Point's Fourth Six-Month Status Report Update 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.

10. NRC Interim Staff Evaluation "Nine Mile Point Nuclear Station, Unit 1 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 2 of the Order EA-13-109 (Severe Accident Capable Hardened Vents (TAC NO. MF4481)", dated August 30, 2016.

Page 18 of 19

Nine Mile Point Nuclear Station, Unit 1 Fifth Six~Month Status Report for Implementation of HCVS Phases 1 and 2 Sketch 1A: Electrical Layout of System - HCVS LIGHTING PANEL LP106 CKT. *16 l---~ MANUAL BKR-CHCVS>B )

f TRANSFER SWITCH 10A HOS-HCVS-PG PLUG FOR MDN-201.13-200 PORTABLE GENERATOR OUTLET-HCVS-PG 125VDC CHARGER 125VOC BATTERY

. I BC-HCVS BOARD *12, CUB Cl2 125VDC CFLEX POWER> BATTERY SEE DWG.Cl9B39C-002 BAT-HCVS

'-'""°"

BKR-<HCVS)3 ) BKR-CHCVS>2 )

15A 10A SEE NOTE 2 125VDC BUS PNL-HCVS BKR-<HCVS>4 BKR-<HCVS>7 BKR-<HCVSJ5 BKR - <HCVS>6

) IA ) LA ) LA ) 2A HCVS Vl-201.13-80 125VOC/24VOC RT-20l.13-79A VALVE CONVERTER HCVS RAD I AT !ON CONTROL PWRS-<1S90> L MONITOR SEE OWG.F45940C-00L NOiES:

I. NJT USED.

2. EREAKER IS KEPT OPEN DURING PLANT NORMAL OPERATION AND CLOSED ONLY IF REQUIRED CURING A BEYOND DESIGN BASIS EXTERNAL EVE'lT(BDBEE>.

Page 19 of 19

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 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 (24 pages)

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 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 Nine Mile Point Unit 2 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 six month status report updates the milestone accomplishments based on the combined Phases 1 and 2 Overall Integrated Plan dated December 15, 2015 (Reference 7) and last updated on June 30, 2016 (Reference 10).

Nine Mile Point Unit 2 developed an updated and combined Phases 1 and 2 Overall Integrated Plan (Reference 7 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 combined Phases 1 and 2 Overall Integrated Plan and the last six month update, 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 last six-month update was submitted under Reference 10, and are current as of December 2, 2016.

• Fifth Six-Month Update (complete with this submittal)

Page 1 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 3 Milestone Schedule Status The following provides an update to the Part 5 Milestone Schedule of the Overall Integrated Plan. It provides the activity status of each item, and whether the expected completion date has changed. The dates are planning dates subject to change as design and implementation details are developed.

NMP2 - Phase 1 Specific Milestone Schedule Target Activity Comments Milestone Completion Status Date Hold preliminary/conceptual design meeting November Complete 2013 Submit Overall Integrated Implementation June 2014 Complete Plan Submit 6 Month Status Report December Complete 2014 Design Engineering Complete March 2015 Complete Submit 6 Month Status Report June 2015 Complete Operations Procedure Changes Developed December Complete 2015 Submit 6 Month Status Report December Complete Simultaneous with 2015 Phase 2 OIP Training Complete February Complete 2016 NMP2 Implementation Outage April 2016 Complete Procedure Changes Active April 2016 Complete Walk Through Demonstration/Functional Test April 2016 Complete Submit Fourth 6-Month Status Report June 2016 Complete Submit Completion Report June 2018 Not Started Page 2 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 NMP2 - Phase 2 Specific Milestone Schedule Target Activity Comments Milestone Completion Status Date Submit Overall Integrated Implementation December Complete Plan 2015 Hold preliminary/conceptual design meeting January Complete 2016 Submit 6 Month Status Report June 2016 Complete Submit 6 Month Status Report December Complete 2016 with this submittal Design Engineering On-site/Complete August Not Changed from 2017 Started March 2017 Submit 6 Month Status Report June 2017 Not Started Operations Procedure Changes Developed December Not 2017 Started Site Specific Maintenance Procedure December Not Developed 2017 Started Submit 6 Month Status Report December Not 2017 Started Training Complete February Not 2018 Started Implementation Outage April 2018 Not Started Procedure Changes Active April 2018 Not Started Walk Through Demonstration/Functional Test April 2018 Not Started Submit Completion Report June 2018 Not Started 4 Changes to Compliance Method There are no changes to the compliance method as documented in the combined Phases 1 and 2 Overall Integrated Plan (Reference 7).

Page 3 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 5 Need for Relief/Relaxation and Basis for the Relief/Relaxation Nine Mile Point Unit 2 complied with the Phase 1 order implementation date and expects to comply with the Phase 2 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, the Reference 6 Interim Staff Evaluation (ISE) for Phase 1, and the Reference 11 ISE for Phase 2 and the status of each item.

• Phase 1 Open Items from OIP Status OIP Phase 1 Open Item No. 1 Deleted (closed to ISE open item number 8 below)

OIP Phase 1 Open Item No. 2 Deleted (closed to ISE open item number 3 below)

OIP Phase 1 Open Item No. 3 Deleted (closed to ISE open item number 9 below)

OIP Phase 1 Open Item No. 4 Deleted (closed to ISE open item number 2 below)

OIP Phase 1 Open Item No. 5 Deleted (closed to ISE open item number 4 below)

OIP Phase 1 Open Item No. 6 Deleted (closed to ISE open item numbers 10 and 12 below)

OIP Phase 1 Open Item No. 7 Deleted (closed to ISE open item number 7 below)

OIP Phase 1 Open Item No. 8 Deleted (closed to ISE open item number 7 below)

OIP Phase 1 Open Item No. 9 Submitted for closure in Reference 10 ISE Phase 1 Open Items Status ISE Phase 1 Open Item No. 1 Submitted for closure in Reference 10 ISE Phase 1 Open Item No. 2 Submitted for Closure in Reference 7 Page 4 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 ISE Phase 1 Open Item No. 3 Submitted for closure in Reference 10 ISE Phase 1 Open Item No. 4 Submitted for Closure in Reference 7 ISE Phase 1 Open Item No. 5 Submitted for closure in Reference 10 ISE Phase 1 Open Item No. 6 Submitted for Closure in Reference 7 ISE Phase 1 Open Item No. 7 Submitted for closure in Reference 10 ISE Phase 1 Open Item No. 8 Submitted for closure in Reference 10 ISE Phase 1 Open Item No. 9 Submitted for Closure in Reference 7 ISE Phase 1 Open Item No. 10 Submitted for closure in Reference 10 ISE Phase 1 Open Item No. 11 Submitted for closure in Reference 10 and updated with this update as provided in table below.

ISE Phase 1 Open Item No. 12 Submitted for closure in Reference 10 ISE Phase 1 Open Item No. 13 Submitted for closure in Reference 10 OIP Phase 2 Open Items Status OIP Phase 2 Open Item No. 1 Started ISE Phase 2 Open Items Status ISE Phase 2 Open Item No. 1 Started ISE Phase 2 Open Item No. 2 Not Started ISE Phase 2 Open Item No. 3 Not Started ISE Phase 2 Open Item No. 4 Not Started The table below documents the completion of the final remaining open items as listed above. As stated above, EGC provides the response for the following items and considers them to be complete for Nine Mile Point Nuclear Station, Unit 2.

Page 5 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 1 Open Items Item Description Status OIP Phase 1 Open Radiological Calculation H21C-114 has been Complete Item No. 9 completed to provide assurance that personnel can Perform safely operate the NMP2 HCVS and respond to radiological required ERO response actions during severe evaluation for accident conditions. Calculation was performed Phase 1 vent line using NRG endorsed HCVS-WP-02 and HCVS-impact on ERO FAQ-12 methodologies.

response actions.

Calculation H21 C-114 has been posted in ePortal for NRC's review.

Page 6 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open Seismic Design of the outdoor HCVS stack Complete Item No. 1 The HCVS piping contains ASME Class 2, 3 and Make available for ANSI B31 .1 piping. The entire HCVS system has N RC staff audit the been evaluated to Seismic Category I requirements seismic and in pipe stress calculation AX-515B consistent with tornado missile the plants seismic design basis to comply with NEI final design criteria 13-02, Section 5.2 seismic design guidance. Per for the HCVS stack. NRC Letter, May 9, 2014 "

Subject:

Screening and Prioritization Results Regarding Information Pursuant to Title 10 of the Code of Federal Regulations 50.54(f) Regarding Seismic Hazard Re-Evaluations for Recommendation 2.1 of the Near-Term Task Force Review of Insights from the Fukushima Dai-ichi Accident", the NRC concluded that NMP2 "screened out" of performing the seismic risk evaluation as part of the Containment Purge System (CPS) I HCVS seismic analysis. Therefore, the more severe seismic load case (2xSSE) is not required as part of the BOB analysis of the CPS/HCVS system. Pipe stress calculation AX-515B is available in the ePortal for NRC review.

Missile Protection of the outdoor HCVS stack NEI 13-02, Section 5.1.1 .6 requires that missile impacts are to be considered for portions of the HCVS. The Nuclear Energy Institute (NEI) issued a white paper HCVS-WP-04, endorsed by the NRC, which provides a risk-informed approach to evaluate the threat posed to exposed portions of the HCVS by wind-borne missiles. The white paper concludes that the HCVS is unlikely to be damaged in a manner that prevents containment venting by wind-generated missiles coincident with an ELAP or LUHS, for plants that are enveloped by the assumptions in the white paper.

A NMP2 specific missile evaluation is documented in the Engineering Change Package (ECP) consistent with HCVS-WP-04. The conclusion of the evaluation is that NMP2 meets all of the tornado missile assumptions identified in HCVS-WP-04 and as such ,

supplementary protection is not required for the HCVS piping and components. The ECP missile Page 7 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status evaluation is available in the eportal for NRC review.

ISE Phase 1 Open The December 2015 OIP update contains a more Complete Item No. 2 detailed description of the seismic adequacy of the ROS location.

Make available for NRC staff review documentation of a determination of seismic adequacy for the ROS location in the Reactor Building Track Bay.

ISE Phase 1 Open The HCVS was designed to have the capacity to Complete Item No. 3 vent the steam equivalent of a decay heat rate of 1%

of the rated thermal power at a pressure equivalent Make available for to the lessor of containment design pressure or the NRC staff audit PCPL consistent with NEI 13-02 Section 4.1.1.1 analyses guidance. The design pressure was used which is demonstrating that 45 psig at NMP2. This is equivalent to a flow rate of HCVS has the approximately 148,600 lbm/hr. The current design capacity to vent the has been evaluated considering pipe diameter, steam/energy length, and geometry as well as vendor provided equivalent of one valve Cv's, and the losses associated with a burst (1) percent of rupture disc. Calculation A 10.1-A-050 concludes licensed/rated that the design provides margin to the minimum thermal power required flow rate. Calculation A 10.1-A-050 is (unless a lower available for NRC review in the ePortal.

value is justified) and that the Additionally, MAAP 4.0.6 analyses in Calculation N2-suppression pool 2014-004 were performed to investigate the and the HCVS response of the NMP2 containment venting using together are able to the new HCVS vent parameters and the use of RPV absorb and reject alternate injection with assumed RCIC failure at 240 decay heat, such

°F in the suppression pool. The objective of the that following a analysis was to understand the overall accident reactor shutdown response signature and key containment (wetwell from full power and drywell) thermal-hydraulic behavior. The MAAP containment analyses demonstrate that the suppression pool and pressure is the HCVS together are able to absorb and reject restored and then decay heat, such that following a reactor shutdown maintained below from full power containment pressure is restored and the primary then maintained below the primary containment Page 8 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status containment design design pressure and the primary containment pressure and the pressure limit. Calculation N2-2014-004 is available primary for NRC review in the ePortal.

containment pressure limit.

Page 9 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open As required by EA-13-109, Section 1.2.11, the Complete Item No. 4 HCVS design will include an Argon purge system Provide a that will be connected just downstream of the HCVS isolation valve. It will be designed to prevent description of the final design of the hydrogen detonation downstream of that valve.

HCVS to address However, the Argon purge system is required to be used only if the ELAP progresses to severe accident hydrogen detonation and conditions which result in the creation of hydrogen.

def lag ration. The Argon purge system will have a switch for the control valve in the MCR to allow opening the purge for the designated time, but it will also allow for local operation in the ROS in case of a DC power or control circuit failure. The installed capacity for the Argon purge system will be sized for 6 purges within the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of the ELAP. Evaluation N2-MISC-003, "MAAP Analysis to Support SAWA Strategy" shows that in a severe accident, NMP2 would not be expected to exceed 6 vent cycles in the first 24-hour period. The design allows for Argon bottle replacement for continued operation past 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The argon system was sized in calculation A 10.1-P-053 which has been loaded on the ePortal.

The Argon purge system can also be used to breach the rupture disc. The MCR panel will include an indication of vent line pressure upstream of the disc to show when the disc has burst due to the increased Argon pressure.

Page 10 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open At NMP2, the primary operating station for HCVS Complete Item No. 5 operation is located in the MCR. A HCVS remote Make available for operating station (ROS) is located in the RB Track NRC staff audit Bay. The location was ~valuated for habitability and documentation that accessibility during a severe accident. Onsite demonstrates communications will be performed using either the adequate installed sound powered headset system or the 450 communication MHz radios in the talk around mode, or a between the combination thereof. A sound powered phone jack is remote HCVS available near the ROS to communicate with the rest operation locations of the plant.

and HCVS decision makers during Offsite communications will utilize fixed satellite ELAP and severe phones in the Control Room and Technical Support accident conditions. Center (TSC). Both locations also have portable satellite phones staged.

Communications protocol for beyond design basis events are documented in CC-NM-118 and procedure N2-0P-76 which are available for NRC review in the ePortal.

These communication methods are consistent with FLEX communication practices at NMP2 and have been previously reviewed by the staff as documented in a communications safety assessment regarding NTTF Rec 9.3 Communications for NMP (ML13100A236).

P!:lru:=! 11 of ?LI.

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open The December 2015 OIP update contains a more Complete Item No. 6 detailed description of how the design addresses Provide a hydrogen detonation and deflagration. Refer to the description of the discussion subtitled "Unintended Cross Flow of strategies for Vented Fluids" on page 16 of 66 in the December hydrogen control 2015 OIP for details as to how hydrogen gas that minimizes the migration and ingress into the reactor building or potential for other buildings is minimized.

hydrogen gas migration and ingress into the reactor building or other buildings.

P::\no 1? nf ~Ll

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open Temperature Evaluation: Complete Item No. 7 Make available for Accessing HCVS equipment, following an external N RC staff audit an event that results in an ELAP, will subject the evaluation of operator to prevailing area temperatures. The temperature and majority of the operator travel path from the MGR to radiological the ROS is outdoors. Therefore, the travel path conditions to does not pose any habitability concerns, with respect ensure that to temperature. The MGR and ROS are expected to operating remain habitable, with respect to temperature, during personnel can the event. During the ELAP, as with the station safely access and blackout, normal ventilation systems are inoperable operate controls and non-vital equipment is not contributing to the and support area heat load. Therefore, area temperatures in the equipment. MGR will be higher than that for normal operation and likely more in line with that for station blackout.

The expected peak area temperature for the MGR is 100 °F. This is based on Calculation ES-198 which predicts the control room heat-up following a station blackout. The calculation assumes doors to the control room will be open. Procedural directions is provided in Station Blackout/ELAP procedure N2-SOP-01 to block open control room doors for additional cooling when normal ventilation is lost.

The area temperature for the ROS in the Track Bay is not expected to undergo any appreciable change as a result of the event. There is no vital equipment in the area that would be operating, adding to the heat load, and the space has a 20' vertical height, which will moderate the area temperature.

Additionally, the Track Bay door to the outside can be opened to moderate the temperature, if needed.

Radiological Evaluation:

The radiological dose Calculation H21C-114 is described in detail under the response to OIP Phase 1, Open Item No. 9 above.

In accordance with the definition of sustained operations in NEI 13-02, the integrated radiation dose due to HCVS operation over a 7-day period Page 13 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status was determined in Calculation H21 C-114. The 7-day dose determined in the calculation due to HCVS operation is a conservative maximum integrated radiation dose over a 7-day period with ELAP and fuel failure starting at reactor shutdown. For the sources considered and the methodology used in the calculation, the timing of HCVS vent operation or cycling of the vent will not create higher doses at personnel habitability and equipment locations (i.e.,

maximum doses determined in the calculation bound operational considerations for HCVS vent operation).

The operator travel path is designed to minimize the dose to the operator from shine off of the HCVS vent pipe on the west side of the Reactor Building. The dose rates along the majority of the path are heavily shielded from the HCVS vent pipe and would not be significant(< 1 mR/hr) . The dose rate between the Control Building and the Maintenance Building could be significant (several R/hr). However, the exposure to this dose rate would be for a few seconds and the accumulated dose would not be significant.

Peak maximum dose rates and 7-day total integrated dose have been calculated for the POS and the ROS in Calculation H21C-114. The radiation dose to personnel occupying defined habitability locations, resulting from HCVS operation are below the 5 rem acceptance criteria as shown below:

MCR: 7-day Total Integrated Dose= 4.1 rem ROS: 7-day Total Integrated Dose< 1 rem Therefore, during the 7 days of sustained operation for BDBEE, the predicted environmental and radiological conditions will be acceptable for the operators to gain access to areas required for HCVS operation in the MCR and ROS. The above referenced calculations are available in the ePortal for NRC review.

Page 14 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open Batteries/Battery Charger Sizing: Complete Item No. 8 Make available for The new battery selected is a sixty (60) cell GNB NRG staff audit the battery, with the battery cells connected in series to final sizing create 125VDC nominal voltage. The battery is a evaluation for Valve Regulated Lead Acid (VRLA) type rated for HCVS 104 ampere-hours. The battery is selected in batteries/battery accordance to IEEE-485. The Battery Sizing charger including Requirements indicates that based on 2.3 ampere incorporation into loading requirements for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> duty period, a FLEX DG loading minimum of a sixty (60) cell, 90.3 ampere-hours calculation. battery is required to bound the required battery duty cycle and end-of-cycle battery terminal voltage requirements. The selected battery capacity of 104 ampere-hours is more than the minimum required 90.3 ampere-hours battery capacity. Therefore, the selected battery is adequate.

The battery charger is rated for 130 volts nominal DC output voltage, 10 amperes nominal DC output current, 120 volts AC input voltage and a current limit adjustment range of 50% - 120%. The battery/battery charger sizing requirements evaluation is available in the ePortal for NRG review.

Incorporation into FLEX DG Loading Calculation:

Following a BOBE, the battery charger is expected to draw a maximum load of 2.9 kVA. This load will be credited in the NMP2 FLEX Portable Diesel Generator Calculation EC-206 which was revised to reflect the load addition of the battery charger. The additional load added is still within the capability of the NMP2 FLEX Diesel Generator and therefore, this change is acceptable. Calculation EC-206 is available in the ePortal for NRG review.

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Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open P&ID 061-D outlines the functional design of the Complete Item No. 9 pneumatic system. Calculation A 10.1-P-051 Make available for determines the required amount of Nitrogen needed NRC staff audit for the required number of vent cycles in a 24-hour documentation of period.

the HCVS nitrogen The P&ID and calculation are loaded on the ePortal.

pneumatic system design including sizing and location.

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Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open New components related to HCVS operation are Complete Item No. 10 required to be designed to operate following a seismic event. Most equipment came qualified or Make available for evaluated by the vendor. However, some equipment NRG staff audit was purchased as commercial grade (non-safety documentation of a related) and was shake tested in order to prove the seismic components' ability to withstand a bounding seismic qualification event.

evaluation of HCVS components.

Qualification/evaluation documentation provided by the vendor, or test results from shake tests were compiled into a single report for HCVS dedicated equipment (Ref. VENRPT-15-000013) with the exception of separate seismic design reports for the PCIVs and HCVS pressure control valve 2CPS-AOV134. These reports are available in the ePortal for NRG review.

ISE Phase 1 Open Existing Instrumentation: Complete Item No. 11 and In the Phases 1 and 2 combined HCVS OIP, Part 2: Revised in Make available for Key Venting Parameters section, both drywell this NRG staff audit pressure and suppression chamber pressure and December descriptions of all suppression pool level are listed as key parameters. 2016 instrumentation and Other Part 2 OIP sections only list drywell pressure Update controls (existing and suppression pool level as key parameters. In and planned)

Part 3 of the OIP, drywell pressure and suppression necessary to pool level are stated as the key parameters for implement this SAWM operations. The following discussion has order including been revised since the June 2016 six-month update qualification to clarify what key parameters are used for HCVS methods.

initiation and cycling for Phases 1 and 2.

Existing control room indications for wetwell (suppression chamber) pressure and suppression pool (primary containment) water level are used for HCVS venting operation. Operation of the HCVS will be based on guidance in the EOPs and SAPs and will follow the primary containment pressure limit (PCPL) curves contained in these procedures. The PCPL curves use suppression chamber pressure vs.

primary containment water level parameters to determine when to vent containment. Therefore, containment wetwell pressure indication is preferred Page 17 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status to determine the need, timing and effectiveness of the venting operation following a BDBEE, in order to ensure that containment pressure does not exceed the PCPL. Existing control room indication for wetwell pressure, shown on 2CMS*Pl7A (Division 1) and 2CMS*PR7B (Division 2), will be used for this purpose. These indicators receive pressure signals from pressure transmitters 2CMS*PT7A and 2CMS*PT7B, respectively. These pressure transmitters sense the wetwell pressure from penetrations Z-337-1 and Z-338-1, both located at elevation 224'-0".

Drywell pressure instrumentation may also be referenced during the event. Existing control room indication for drywell pressure, shown on 2CMS*Pl2A (Division 1) and 2CMS*PR2B (Division 2), will be used for this purpose. These indicators receive pressure signals from pressure transmitters 2CMS*PT2A and 2CMS*PT2B, respectively.

Wetwell level indication is needed to determine that the wetwell vent path is preserved. Wetwell level is displayed on indicator 2CMS*Ll9A (Division 1) and 2CMS*LR9B (Division 2). These indicators receive level signals from level transmitters 2CMS*LT9A and 2CMS*LT9B, respectively. Both of the instruments interface with the suppression pool at low and high elevation of 192' and 217' and can therefore monitor between those elevations. The inlet to the HCVS vent pipe is at elevation 227'. Therefore, water level will have to be maintained below 217' in order to ensure that the vent inlet does not get covered with water.

The pressure and level indicators and related transmitters are all Safety Related, Regulatory Guide 1.97 compliant components (Ref. NMP2-RG197-01 ).

They are also environmentally qualified for accident conditions (Ref. 2EQDP-XMTR001 ). Division 1 is the FLEX diesel power backed loop, and Division 2 can be powered as an alternate strategy.

Additionally, containment pressure and/or wetwell level can be obtained from a Transmation 1045 (or Page 18 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status similar loop calibrator) at the associated transmitter or Relay Room panel. NMP2 procedure N2-SOP-78A, EOP Key Parameter - Alternate Instrumentation, provides direction on how to obtain readings from transmitters using this hand-held test equipment.

The FLEX Phase 2 primary strategy is to provide power using a FLEX generator to Division 1 600 VAC unit substation to maintain instrumentation power supply and the back-up is Division 2.

Depending on availability, either loop may be used for containment pressure and wetwell level determination.

New HCVS Instrumentation and Controls:

The l&C scope for the HCVS is to display the following and to control the SOVs associated with the new primary containment isolation valves from new control room panel 2CEC-PNL801 located in the Main Control Room. The SOVs are controlled via key-lock control switches.

• HCVS Isolation Valve Position Indication

• Temperature, Pressure and Radiation of the HCVS Pipe

• HCVS Purge System Supply Pressure (Local indication only)

• HCVS Battery Voltage New track bay control panel 2CPS-PNL 100 serves as the main power distribution for all l&C components.

A detailed description of existing and new I &C components including qualification methods is included in the Engineering Change Package and is available on the ePortal for NRC review.

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Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open The HCVS is located in Primary Containment, Complete Item No.12 Secondary Containment, the Reactor Building Track Bay, the Control Room, and outside the Reactor Make available for Building. Environmental conditions and impacts are NRG staff audit the evaluated in detail in the Engineering Change description of local Package (ECP). The ECP includes a listing of the conditions components in each area along with the (temperature, corresponding environmental conditions including radiation, and temperature, radiation and humidity. The ECP also humidity) includes a detailed listing of environmental anticipated during qualification requirements. The complete listing and ELAP and severe information from the ECP is available on the ePortal accident for the for NRG review.

components (valves, On November 17, 2016 a teleconference between instrumentation, Exelon and the NRG was held to review NMP2

sensors, transmitters, Phase 1 closure of open items. In this call NMP clarified that consistent with NEI 13-02 Appendix C indicators, section C.8.1, no further environmental qualification electronics, control of existing containment parameter monitoring devices, etc.)

instrumentation is required if the instrumentation is required for HCVS already RG 1.97 qualified.

venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions.

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Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Item Description Status ISE Phase 1 Open The existing containment isolation valves Complete Item No. 13 2CPS* AOV109 and 2CPS* AOV111 were replaced with new valves. Additionally, an HCVS containment Make available for pressure control valve (2CPS-AOV134) located NRG staff audit downstream of the containment isolation valves was documentation of added to control vent flow after the containment an evaluation isolation valves are opened during a BDBEE.

verifying the existing Actuator capability and margin calculations were containment performed using the Sargent & Lundy AirBase isolation valves software program for the three AOVs. The relied upon for the calculations are intended to confirm that the AOVs HCVS, will open can open under the maximum expected differential under the pressure (MEDP) during BDBEE and severe maximum expected accident wetwell venting.

differential pressure during BDBEE and Under an ELAP or for severe accident wetwell severe accident venting the subject valves are closed and without wetwell venting.

their normal supply of air power. Prior to exceeding the primary containment pressure limit (PCPL),

Operators open the valves remotely using the dedicated HCVS batteries and nitrogen bottles. The MEDP is determined based on assuming the maximum upstream pressure is equal to the PCPL of 45 psig and by conservatively using a downstream pressure equal to vacuum pressure

(-14. 7 psig) since exhausting steam may condense in the HCVS line, creating a negative pressure. Thus the MEDP used in the calculations is 59.7 psid.

Calculation A 10.1-P-047 for 2CPS*AOV109/111 shows actuator torque required vs. actuator torque available margins for the closed to full open stroke in the range of 49% to 189%. Calculation A 10.1-P-052 for 2CPS-AOV134 shows margins from the closed to full open stroke in the range of 78% to 233%. The calculations demonstrate positive margin in the opening direction. The calculations are available in the ePortal for NRG review.

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Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Phase 2 OIP Open Items Item Description Status OIP Phase 2 Open Perform radiological evaluation to determine Started Item No.1 feasibility of reactor building actions.

ISE Phase 2 Open Licensee to provide the site-specific MAAP Started Item No. 1 evaluation that establishes the initial SAWA flow rate (ISE Section 3.3.2.2)

ISE Phase 2 Open Licensee to demonstrate that containment failure as Not Started Item No. 2 a result of overpressure can be prevented without a drywell vent during severe accident conditions (ISE Section 3.3.3).

ISE Phase 2 Open Licensee to demonstrate that there is adequate Not Started Item No. 3 communication between the MCR and the operator at the FLEX manual valve during severe accident conditions (ISE Section 3.3.3.4).

ISE Phase 2 Open Licensee to demonstrate the SAWM flow Not Started Item No. 4 instrumentation qualification for the expected environmental conditions (ISE 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. However, as revised in the response to ISi Open Item 11 above the existing containment instrumentation credited has been changed. Additionally, clarifications to various electrical discussions in the Reference 7 combined OIP are provided as follows:

Page 11 of 66, fourth bullet under the time constraint discussion 24 Hours, Connect back-up power to HCVS battery charger. The HCVS battery is calculated to last a minimum of 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> (ISE Open Item #8). The HCVS battery charger will be able to be re-powered either from the 600V AC bus permanently connected to the HCVS battery charger (via a 600 - 120/240 V AC step-down distribution transformer) that will be re-powered from a portable diesel generator (DG) put in place for FLEX or locally (Reactor Building Track Bay) from a small portable generator. The DG will be staged and placed in service within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> (Reference 1) and therefore will be available prior to being required. In the event that the DG is not available, a local connection will allow a small portable generator to be connected to the HCVS battery charger to provide power. Connection of a small portable generator is achievable within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

Page 14 of 66, under "Power and Pneumatic Supply Sources" All electrical power required for operation of HCVS components will be provided by a dedicated HCVS battery charger and battery. The HCVS battery has a minimum Page 22 of 24

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2 capacity capable of providing power to the HCVS loads for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> without recharging. An evaluation has been completed as part of the detailed design process (ISE Open Item #8). The HCVS battery charger provided requires a 120 VAC supply. This will be supplied by a 600 VAC bus (via a 600 - 120/240 VAC step-down distribution transformer) that will be re-powered by a portable diesel generator as part of the FLEX response. In addition, a connection point that utilizes standard 120 VAC electrical connections will be provided locally for a portable generator for sustained operation of the HCVS.

Page 21 of 66, 4th paragraph under Greater than 24 Hour Coping Detail The HCVS battery and battery charger will also be installed in the Reactor Building Track Bay. The HCVS battery has a capacity sufficient for 24-hour operation. The normal power supply to the HCVS battery charger will be provided from a 600 V AC bus (via a 600 - 120/240 VAC step-down distribution transformer) that will be re-powered by a portable diesel generator as part of the FLEX response. A design change to install the portable diesel generator external connection points to this bus has been completed in support of EA-12-049 (Reference 1). In the event that power is not restored to the bus, a local 120 V AC connection will allow the HCVS battery charger to receive power from a small portable generator. Actions to replenish the electrical supply include refueling the DG or connecting and refueling a small portable generator.

Page 26 of 66, 5th paragraph under general description of venting actions support functions The HCVS battery and battery charger will also be installed in the Reactor Building Track Bay. The HCVS battery has a capacity sufficient for 24-hour operation. The normal power source for the HCVS battery charger is a 120/240 V AC rated distribution panel which is fed by a 600 V AC bus (via a 600 - 120/240 VAC step-down distribution transformer) that will be re-powered by a portable diesel generator as part of the FLEX response. A design change to install the portable diesel generator external connection points to this bus has been completed in support of EA-12-049 (Reference 1). In the event that power is not restored to the 600 V AC bus, a local 120 V AC connection to the HCVS battery charger will allow the HCVS battery charger to receive power from a small portable generator. Actions to replenish the electrical supply include refueling the DG or connecting and refueling a small portable generator.

8 References The following references support the updates to the combined Phases 1 and 2 Overall Integrated Plan described in this enclosure.

1. Nine Mile Point Unit 2's 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 27, 2014.

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Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Fifth Six-Month Status Report for Implementation of HCVS Phases 1 and 2

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 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. ML13304B836).

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 Evaluation "Nine Mile Point Nuclear Station, Unit 2 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 1 of the Order EA-13-109 (Severe Accident Capable Hardened Vents (TAC NO.

MF4482)", dated February 11, 2015.

7. Nine Mile Point Unit 1's Combined Phase 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.

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

Revision 0, dated April 2015 (Accession No. ML15104A118).

9. Letter from M.G. Korsnick (GENG) to Document Control Desk (NRC), Overall Integrated Plan for Mitigation Strategies for Beyond-Design-Basis External Events, dated February 28, 2013.

10. Nine Mile Point's Fourth Six-Month Status Report Update 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 109)," dated June 30, 2016.

11. NRC Interim Staff Evaluation "Nine Mile Point Nuclear Station, Unit 2 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 2 of the Order EA-13-109 (Severe Accident Capable Hardened Vents (TAC NO.

MF4482)", dated August 25, 2016.

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