NMP1L3186, 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 ...

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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 ...
ML17349A031
Person / Time
Site: Nine Mile Point  Constellation icon.png
Issue date: 12/15/2017
From: Jim Barstow
Exelon Generation Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-109, NMP1L3186, RS-17-154
Download: ML17349A031 (33)
v • d • e


Text

Exelon Generation Order No. EA-13-109 RS-17-154 NMP1L3186 December 15, 2017 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 NPF-69 NRC Docket Nos. 50-220 and 50-41 O

Subject:

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)

References:

1. NRC Order Number EA-13-109, "Issuance of Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," dated June 6, 2013
2. NRC Interim Staff Guidance JLD-ISG-2013-02, "Compliance with Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions", Revision 0, dated November 14, 2013
3. NRC Interim Staff Guidance JLD-ISG-2015-01, "Compliance with Phase 2 Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions", Revision O, dated April 2015
4. NEI 13-02, "Industry Guidance for Compliance with Order EA-13-109, BWR Mark I & II Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions", Revision 1, dated April 2015
5. Exelon Generation Company, LLC's Answer to June 6, 2013, Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 26, 2013
6. Exelon Generation Company, LLC Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 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 15, 2017 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. 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 14, 2016 (RS-16-236)
12. 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

13. 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

14. 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

15. 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 August25,2016

16. 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-17-067)
17. NRC letter to Exelon Generation Company, LLC, Nine Mile Point Nuclear Station, Unit 2-Report for the Audit of Licensee Responses to Interim Staff Evaluation Open Items Related to NRC Order EA-13-109 to Modify License with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (CAC No.

MF4482; EPID L-2014-JLD-004), dated October 17, 2017

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

Report for the Audit of Licensee Responses to Interim Staff Evaluations Open Items Related to NRC Order EA-13-109 to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (CAC No.

MF4481; EPID L-2014-JLD-0043), dated October 30, 2017

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 December 15, 2017 Page 3 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 IV, Conditions D.2 and D.3 of Reference 1. References 10, 11 and 16 provided the fourth, fifth and sixth six-month status reports respectively, 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 seventh 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 remaining NRC Interim Staff Evaluation open items contained in Reference 16. Responses to the remaining open items were previously uploaded to the NRC ePortal to support the Phase 2 NRC audit teleconference calls for Nine Mile Point Nuclear Station Unit 1 on September 28, 2017 and Nine Mile Point Nuclear Station Unit 2 on October 12, 2017. Closure of the open items is documented in the References 17 and 18 NRC audit reports.

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 151h day of December 2017.

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 December 15, 2017 Page 4 Respectfully submitted, James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosures:

1. Nine Mile Point Nuclear Station, Unit 1 Seventh 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 Seventh 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 NRG Regional Administrator - Region I NRG Senior Resident Inspector - Nine Mile Point Nuclear Station NRG Project Manager, NRR - Nine Mile Point Nuclear Station Mr. Raj Auluck, NRR/JLD/TSD/JCBB, NRG Mr. Brian E. Lee, NRR/JLD/JCBB, NRC Mr. Jason C. Paige, NRR/JLD/JOMB, NRG

Enclosure 1 Nine Mile Point Nuclear Station, Unit 1 Seventh 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" (18 Pages)

Page 1 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 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 and last updated on June 30, 2017 (Reference 12).

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 drywell 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 12, and are current as of December 1, 2017.

  • Phase 2 Design Engineering Complete
  • Seventh Six-Month Update (complete with this submittal)

Page 2 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh 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 January Complete 2017 Submit Combined Phase 1 & 2 Six-Month December Complete Status Report 2016 Submit Combined Phase 1 & 2 Six-Month June 2017 Complete Status Report Maintenance and Operation Procedure February Complete Changes Developed, Training Complete 2017 Implementation Outage April 2017 Complete Procedure Changes Active, Walk-Through April 2017 Complete Demonstration/Functional Test Submit Completion Report June 2019 Not Started Page 3 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh 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 Plan December Complete Simultaneous with 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 Submit 6 Month Status Report June 2017 Complete Submit 6 Month Status Report December Complete 2017 with this submittal Submit 6 Month Status Report June 2018 Not Started Submit 6 Month Status Report December Not 2018 Started Design Engineering Complete April 2018 Complete Maintenance and Operation Procedure February Started Changes Developed, Training Complete 2019 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 4 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh 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. Phase 1 open item responses were discussed with the NRC on November 17, 2016, and all items were adequately addressed and resolved. All additional information has been provided, and the Phase 1 open items are considered closed based on NRC review.

Phase 2 open item responses were discussed with the NRC on October 12, 2017, and all items were adequately addressed and resolved. All additional information has been provided, and the Phases 1 and 2 open items are considered closed based on the Reference 13 NRC audit report.

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

Page 5 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 8 Perform radiological evaluation for Submitted for Closure in Phase 1 vent line impact on ERO Reference 12.

response actions.

Open ISE Phase 1 Open Items Status Item 1 Make available for NRC staff audit the Submitted for Closure in seismic and tornado missile final References 9 and 12.

design criteria for the HCVS stack.

2 Make available for NRC staff audit Submitted for Closure in analyses demonstrating that HCVS References 9 and 12.

has the capacity to vent the steam/energy equivalent of one percent of licensed/rated thermal power (unless a lower value is justified), and that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit.

3 Provide a description of the final Submitted for Closure in design of the HCVS to address References 11 and 12.

hydroqen detonation and deflaqration.

4 Make available for NRC staff audit Submitted for Closure in documentation that demonstrates Reference 9.

adequate communication between the remote HCVS operation locations and HCVS decision makers during ELAP and severe accident conditions.

5 Provide a description of the strategies Submitted for Closure in for hydrogen control that minimizes the References 9 and 12.

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

6 Make available for NRC staff audit an Submitted for Closure in evaluation of temperature and References 11 and 12.

radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

7 Make available for NRC staff audit the Submitted for Closure in final sizinq evaluation for HCVS Reference 9.

Page 6 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 batteries/battery charger including December 2017 Update:

incorporation into FLEX DG loading The Hardened Containment Vent calculation. System (HCVS) Phase 1 Engineering Change Package (ECP) assumed a low ambient temperature in the Turbine Building of 60F during an extended loss of AC power (ELAP) occurring with extreme outdoor cold weather conditions.

Contrary to the Phase 1 assumption, the HCVS Phase 2 ECP assumed a low ambient temperature of 43F during an ELAP based on calculation S 1OHVACHV11. Use of the lower ambient temperature is conservative and is supported by Calculation S10HVACHV11. The impact of applying a 43F ambient temperature to the HCVS design is negligible and does not adversely impact system function.

The 60F ambient temperature was only used in the HCVS Battery Sizing Evaluation contained in the ECP Design Consideration Summary (DCS)

Attachment M. The ambient temperature is used to determine the temperature correction factor which lowers the available battery capacity at lower temperatures.

Using the lower ambient temperature increases the minimum required ampere-hours (AH) battery capacity from 55 AH to 65 AH. The selected battery capacity of 104 AH remains well above the minimum required of 65 AH. This change was documented in Nine Mile Point Issue Report (IR) 04059544 and was previously loaded on the ePortal in the folder entitled "NMP-1 HCVS ISE Open Item Page 7 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Completion Reference Documents".

8 Make available for NRC staff audit Submitted for Closure in documentation of the HCVS nitrogen Reference 9.

pneumatic system design including sizing and location.

9 Make available for NRC staff audit Submitted for Closure in documentation of a seismic Reference 12.

qualification evaluation of HCVS components.

10 Make available for NRC staff audit Submitted for Closure in descriptions of all instrumentation and References 11 and 12.

controls (existing and planned) necessary to implement this order includinq qualification methods.

11 Make available for NRC staff audit the Submitted for Closure in descriptions of local conditions Reference 12.

(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.

Page 8 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 The table below documents the status of the Phase 2 OIP and ISE Open Items which are now closed as indicated in the Status column below.

Phase 2 OIP and ISE Open Items Item Closure Summary Status Description Phase 2 OIP Deleted (closed to ISE open item number 1 below) Closed Item No. 1 Perform radiological evaluation to determine the SAWA flow control point location.

ISE Phase 2 Refer to the closure summary for ISE Phase 2 Open Complete Open Item Item No. 2. with this No.1 submittal.

Closed by Licensee to Reference confirm 13.

through analysis the temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment (ISE Section 3.3.2.1)

ISE Phase 2 Equipment and Controls Complete Open Item with this No. 2 Plant instrumentation for Severe Accident Water submittal.

Addition/Severe Accident Water Management Closed by Licensee to (SAWA/SAWM) that is qualified to RG 1.97 or Reference evaluate the equivalent is considered qualified for the sustained 13.

SAWA Page 9 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 equipment operating period without further evaluation. The and controls, following plant instruments are qualified to AG 1.97:

as well as ingress and Wetwell Water Level: PT-201.2-594, PT-201.2-680, egress paths Ll-201.2-594C for the Wetwell Water Level: PT-201.2-595, PT-201.2-596, expected Ll-201.2-5950 severe Wetwell Pressure: PT-201.2-595, Pl-201.2-595A accident Wetwell Pressure: PT-201.2-594, Pl-201.2-594A conditions (temperature, The following drywell pressure instruments are also humidity, qualified to AG 1.97 and are available but not radiation) for credited:

the sustained operating Pl-201.2-483A, PT-201.2-483 - Drywell Pressure period (ISE Pl-201.2-484A, PT-201.2-484 - Drywell Pressure Section 3.3.2.3). Passive components that do not need to change state after initially establishing SAWA 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 SAWA/SAWM. Also, the fire hoses used are the "Big 1O" model from Key hose. This hose is a heavy duty double jacketed hose using both polyurethane and EPDM rubber. Per HCVS-OGP-009 these materials will withstand the maximum doses that can be experienced during a severe accident and are therefore acceptable.

The following additional equipment performing an active SAWA/SAWM function is considered:

  • SAWA/SAWM flow instrument.
  • SAWA/SAWM pump
  • SAWA/SAWM generator
  • Active valves in SAWA flow path (Not applicable as there are no active valves in the SAWA flow path)

The above listed additional SAWA/SAWM equipment performing an active function was evaluated for radiation and temperature/humidity as described below:

Page 10 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 SAWA/SAWM flow instrument:

The SAWA flow instrument will be mounted on a cart with a throttling valve and stored in the FLEX Storage Building. During FLEX/SAWA flow injection to the RPV, the cart will be moved into the turbine building near the HCVS Remote Operating Station (ROS). A quantitative evaluation of expected dose rates has been performed per HCVS-WP-02 and found the dose rates at the flow instrument are acceptable. Refer to calculation H21 C115 loaded in the ePortal. The dose rate at the operating location of the flow meter cart (just west of the ROS, between column rows G and H) is 2.25E-05 rem/hr (Ref. Calculation H21C115, Attachment C, Page C3). The area just east of the ROS may be acceptable as well as long as an Operator does not stay at the flow meter for an extended period of time as the dose rate east of the ROS increases to 7.335E-01 rem/hr per H21C115 Page C3. Using the higher dose rate, the total dose over the 7-day period is 123 rem. This dose is well below the generally accepted maximum for digital equipment, 1000 rem (Ref. EPRI 1009659, Generic Qualification and Dedication of Digital Components, March 2005, Page 6-2, second paragraph). The flow meter is commercial equipment and does not have a published radiation dose limit.

The selected instrument is designed for the expected flow rate, temperature and pressure for SAWA over the period of sustained operation.

SAWA Flow Instrument Expected SAWA Qualification Parameter Range

-2 to 544 GPM 54 to 263 GPM

-4 to 140 °F 43 to 98 °F 740 PSI MAX 365 PSI MAX The above flow instrument information is taken from vendor manual NOB035001NDREC001 pages 44 and 45 for the 2.5-inch Badger Meter ModMAG M5000 flowmeter with 300# flanges specified for this application. The above ambient temperature range is based on calculation S10HVACHV11, Area TR shown on Figure 2 Page A-6 with the results from page 17 for Page 11 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Area TR. The maximum pressure of 365 psi is the FLEX pump shutoff head at maximum pump speed.

SAWA/SAWM Pump:

The SAWA pump is the FLEX pump and the location remains as was previously evaluated for the FLEX location. The 7-day dose from the U1 HCVS vent pipe when crediting shielding provided by the screenhouse walls and traffic barriers is reported on page 93 of calculation H21 C115 to be 51.3 rem. The dose from the U2 HCVS vent pipe is not added because per HCVS FAQ 10, it is not required to assume severe accident conditions at each unit on a dual unit site.

The 7-day dose is acceptable per the same basis provided above for the flow meter. The SAWA pump would be exposed to the same high and low outdoor ambient temperature conditions addressed under FLEX.

SAWA/SAWM generator:

The SAWA generator is the FLEX generator and the location remains as was previously evaluated for the FLEX location. The 7-day dose from the U1 HCVS vent pipe is 23.5 rem as reported on page 93 of calculation H21 C115. The dose from the U2 HCVS vent pipe is not added because per HCVS FAQ 10, it is not required to assume severe accident conditions at each unit on a dual unit site. The 7-day dose is acceptable per the same basis provided above for the flow meter. The SAWA generator would be exposed to the same high and low outdoor ambient temperature conditions addressed under FLEX.

Ingress and Egress Actions taken within the first hour (prior to start of core damage) from the start of the ELAP are acceptable from an environmental and radiological perspective without further evaluation.

Actions performed within the MCR are acceptable for the entire period of Sustained Operation per HCVS-FAQ-06 Assumption 049-21 .

Page 12 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 A quantitative evaluation of expected dose rates has been performed per HCVS-WP-02 and found the dose rates at deployment locations for the SAWA throttle valve and flow meter cart including ingress and egress paths are acceptable. SAWA flow will be throttled using the throttle valve on the cart. The cart will be deployed adjacent to the ROS in the turbine building.

Therefore, the evaluations in calculation H21C115 for Operator travel paths and for operating the HCVS ROS controls would also apply to operating the throttle valve and flow meter cart.

There are no Operator actions required in the reactor building to inject SAWA flow to the RPV. While there are no specific Operator actions in the reactor building required for SAWA flow injection, change notice ECP-17-000279 HC1 C115 was performed to assess Operator actions in the event that Operators decide to enter the reactor building prior to venting for other reasons, which may expose them to radiation shine from containment structures. Attachment I in the change notice assesses dose rates to operators in the event they decide to enter the reactor building during Phase 2 venting and provides insights as to areas to avoid. The assessment performed resulted in dose rates from containment sources to dose points presented in HC 1C115 Attachment J that would not prevent the operators from accessing the areas to perform SAWA actions during the first 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> post-ELAP.

High and low ambient temperatures in the turbine building area TR per S10HVACHV11 during the 7-day period are below maximum personnel habitability temperatures and will not prevent Operators from performing required actions to operate the HCVS/SAWA equipment.

Calculation H21 C115 Table 9.1 also provides maximum stay times over 7 days for Operators at the SAWA pump and diesel generator.

Cautions will be added to procedures to provide guidance for high dose rate areas to minimize dose.

Page 13 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 The following documents have been loaded into the ePortal to support the above evaluations:

  • Calculation H21 C115, "HCVS Radiological Dose Analysis"
  • Change Notice# ECP-17-00279-CN-001 H21C115
  • Vendor Manual N08035001NDREC001, "M-Series Electromagnetic Flow Meter
  • EPRI 1009659, Generic Qualification and Dedication of Digital Components, March 2005
  • Calculation S10HVACHV11 ""Turbine Building Maximum and Minimum Temperature"
  • HCVS FAQ 10 - Severe Accident Response Multiple Unit Site
  • HCVS-OGP-009 - HCVS Hose Radiological Evaluation ISE Phase 2 Refer to the closure summary for ISE Phase 2 Open Complete Open Item Item No. 2. with this No. 3 submittal.

Licensee to Closed by demonstrate Reference how 13.

instrumentatio n and equipment being used for SAWA and supporting equipment is capable to perform for the sustained operating period under the expected temperature and radiological conditions (ISE Section 3.3.2.3).

ISE Phase 2 The wetwell vent has been designed and installed to Submitted Open Item meet NEI 13-02 Rev 1 guidance, which will ensure for closure No. 4 in Page 14 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Licensee to that it is adequately sized to prevent containment Reference demonstrate overpressure under severe accident conditions. 12. Closed that by containment The SAWM strategy will ensure that the wetwell vent Reference failure as a remains functional for the period of sustained 13.

result of operation. Nine Mile Point Unit 1 will follow the overpressure guidance (flow rate and timing) for SAWA/SAWM can be described in BWROG-TP-15-008 and BWROG-TP-prevented 15-011. The wetwell vent will be opened prior to without a exceeding the PCPL value of 43 PSIG. Therefore, drywall vent containment over pressurization is prevented without during severe the need for a drywall vent.

accident conditions (ISE Section 3.3.3).

ISE Phase 2 Submitted Reference Plant Nine Mile Point U1 Open Item for closure No. 5 Torus freeboard Total freeboard in volume is 525,000 1 volume is 862,288 Reference Licensee to gallons gallons 12. Closed demonstrate by how the plant SAWA flow is 500 SAWA flow is 263 Reference is bounded by GPM at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> GPM at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 13.

the reference plant analysis followed by 100 GPM followed by 54 GPM*

that shows the from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to 168 from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to 168 SAWM hours hours strategy is successful in NMP1 has performed a plant specific MAAP analysis making it to establish an initial SAWA flow rate using the above unlikely that a parameters of 263 GPM at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> followed by 54 drywall vent is GPM* from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br />. The MAAP needed (ISE analysis demonstrates that the plant is bounded Section by the reference plant analysis and that the SAWM 3.3.3.1). strategy is successful in making it unlikely that a drywall vent is needed to prevent containment failure (N1-MISC-004).

(*Note that 53 GPM was quoted in the OIP but NMP1 will use 54 GPM in its procedures consistent with the fl owrate used in MAAP) 1 Peach Bottom available freeboard volume in gallons is estimated from nominal water level of 14. 7 feet to 21 feet. 21 feet is the upper range of the wide range torus level instrument and the assumed loss of wetwell vent function. The Peach Bottom torus is 31 feet in diameter.

Page 15 of 18

Nine Mile Point Nuclear Station, Unit 1 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 ISE Phase 2 NMP1 utilizes the installed sound powered headset Submitted Open Item system and/or the 450 MHz radios in the talk around for closure No. 6 mode to communicate between the MGR and the in SAWA flow control location. This communication Reference Licensee to method is the same as accepted in Order EA-12-049. 12. Closed demonstrate These items will be powered and remain powered by that there is using the same methods as evaluated under EA Reference adequate 049 for the period of sustained operation, which may 13.

communicatio be longer than identified for EA-12-049.

n between the MGR and the operator at the FLEX manual valve during severe accident conditions (ISE Section 3.3.3.4).

ISE Phase 2 Refer to the closure summary for ISE Phase 2 Open Complete Open Item Item No. 2. with this No. 7 submittal.

Licensee to Closed by demonstrate Reference the SAWM 13.

flow instrumentatio n qualification for the expected environmental conditions (ISE Section 3.3.3.4).

7 Interim Staff Evaluation (ISE) Impacts There are no new ISE impacts that are in addition to those already described in the Fifth Six-Month status report. Refer to the Reference 11 Six-month status report for the previously described ISE impacts.

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

Page 16 of 18

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

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 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 17 of 18

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

11. Nine Mile Point's Fifth 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 December 14, 2016 (RS-16-236).
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-17-067).
13. NRG letter to Exelon Generation Company, LLC, Nine Mile Point Nuclear Station, Unit 1 -

Report for the Audit of Licensee Responses to Interim Staff Evaluations Open Items Related to NRG Order EA-13-109 to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (CAC No.

MF4481; EPID L-2014-JLD-0043), dated October 30, 2017.

Page 18 of 18

Enclosure 2 Nine Mile Point Nuclear Station, Unit 2 Seventh 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 (11 pages)

Page 1 of 11

Nine Mile Point Nuclear Station, Unit 2 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 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 and last updated on June 30, 2017 (Reference 13).

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 drywell 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 13, and are current as of December 1 , 2017.

  • Phase 2 Design Engineering On-site/Complete
  • Seventh Six-Month Update (complete with this submittal) 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 Page 2 of 11

Nine Mile Point Nuclear Station, Unit 2 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 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 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 Design Engineering On-site/Complete September Complete Changed from 2017 March 2017 Submit 6 Month Status Report June 2017 Complete Operations and Maintenance Procedure December Started Changes Developed 2017 Page 3of11

Nine Mile Point Nuclear Station, Unit 2 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 Submit 6 Month Status Report December Complete 2017 with this submittal 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).

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 item responses were discussed with the NRG on November 17, 2016, and all items were adequately addressed and resolved. All additional information has been provided, and the Phase 1 open items are considered closed based on NRG review.

Phase 2 open item responses were discussed with the NRG on September 28, 2017, and all items were adequately addressed and resolved. All additional information has been provided, and the Phases 1 and 2 open items are considered closed based on the Reference 14 NRG audit report.

Page 4 of 11

Nine Mile Point Nuclear Station, Unit 2 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 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 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 and updated in Reference 13.

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 Page 5 of 11

Nine Mile Point Nuclear Station, Unit 2 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 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 and updated in Reference 13.

ISE Phase 1 Open Item No. 11 Submitted for closure in Reference 10 and updated in Reference 12.

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 The table below documents the status of the Phase 2 OIP and ISE Open Items which are now closed as indicated in the Status column below.

Phase 2 OIP and ISE Open Items Item Closure Summary Status Description OIP Phase 2 Radiological Calculation H21C-114 was previously posted Complete Open Item No. on the ePortal in response to OIP Phase 1 Open Item No. with this 1 9. The calculation performed a dose assessment caused submittal.

by sustained operation of the HCVS under beyond design Closed by Perform basis severe accident conditions for 7 days post-ELAP. Reference radiological Calculation Change Notice ECP-17-000280-CN-001 14.

evaluation to H21C-114 is a minor revision to the parent calculation to determine further assess the dose rate to operators performing feasibility of SAWA actions in the reactor building considering dose reactor building from containment penetrations. Attachment E in the actions.

reference change notice provides this supplemental dose assessment. Attachment E concludes that Operators can perform all preliminary actions in the reactor building within the first 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> post-ELAP to set up the SAWA equipment and then operate the SAWA equipment for 7-days post-ELAP, considering the dose from the HCVS and from containment shine through penetrations, without exceeding a total dose of 5 R.

Calculation Change Notice ECP-17-000280-CN-001 H21C-114 has been loaded onto the NRC ePortal.

Page 6 of 11

Nine Mile Point Nuclear Station, Unit 2 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 ISE Phase 2 Reference Plant Nine Mile Point U2 Submitted Open Item No. Torus freeboard Total freeboard for 1 volume is 525,000 1 volume is 782,000 closure in qallons qallons Reference Licensee to SAW A flow is 500 SAWA flow is 300 13.

provide the GPM at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> GPM at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> Closed by site-specific followed by 100 GPM followed by 100 GPM Reference MAAP from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to 168 from 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> to 168 14.

evaluation that establishes the hours hours initial SAWA NMP2 has performed a plant specific MAAP analysis to flow rate (ISE establish an initial SAWA flow rate using the above Section parameters of 300 GPM at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> followed by 100 GPM 3.3.2.2) from 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br /> to 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br />. The MAAP analysis demonstrates that the plant is bounded by the reference plant analysis and that the SAWM strategy is successful in making it unlikely that a drywell vent is needed to prevent containment failure (N2-MISC-003 Rev 2). The MAAP analysis is loaded on the ePortal for NRC review.

1 Peach Bottom available freeboard volume in gallons is estimated from nominal water level of 14.7 feet to 21 feet. 21 feet is the upper range of the wide range torus level instrument and the assumed loss of wetwell vent function. The Peach Bottom torus is 31 feet in diameter.

ISE Phase 2 The wetwell vent has been designed and installed to meet Submitted Open Item No. NEI 13-02 Rev 1 guidance, which will ensure that it is for 2 adequately sized to prevent containment overpressure closure in under severe accident conditions. Reference Licensee to 13.

demonstrate The SAWM strategy will ensure that the wetwell vent Closed by that remains functional for the period of sustained operation.

Reference containment Nine Mile Point Unit 2 will follow the guidance (flow rate 14.

failure as a and timing) for SAWA/SAWM described in BWROG-TP-result of 15-008 and BWROG-TP-15-011. The wetwell vent will be overpressure opened prior to exceeding the PCPL value of 45 PSIG.

can be Therefore, containment over pressurization is prevented prevented without the need for a drywell vent.

without a drywell vent during severe accident conditions (ISE Section 3.3.3).

Page 7 of 11

Nine Mile Point Nuclear Station, Unit 2 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 ISE Phase 2 NMP2 utilizes the installed sound powered headset Submitted Open Item No. system and/or the 450 MHz radios in the talk around for 3 mode to communicate between the MCA and the SAWA closure in flow control location. This communication method is the Reference Licensee to same as accepted in Order EA-12-049. These items will 13.

demonstrate be powered and remain powered using the same methods Closed by that there is as evaluated under EA-12-049 for the period of sustained Reference adequate operation, which may be longer than identified for EA 14.

communication 049.

between the MCR and the operator at the FLEX manual valve during severe accident conditions (ISE Section 3.3.3.4).

ISE Phase 2 Complete Open Item No. The SAWA flow instrument will be mounted on the FLEX with this 4 valve manifold cart and stored in the reactor building just submittal.

outside of the inner door to the reactor building track bay. Closed by Licensee to During FLEX/SAWA flow injection to the RPV the cart will Reference demonstrate be moved into the RB track bay adjacent to the HCVS 14.

the SAWM flow Remote Operating Station (ROS). A quantitative instrumentation evaluation of expected dose rates has been performed per qualification for HCVS-WP-02 and found the dose rates at the ROS the expected including ingress/egress paths are acceptable (Ref:

environmental Calculation H21 C-114 as amended by ECP-17-00280-CN-conditions (ISE 001 H21C-114). The dose rate at the operating location of Section the flow meter cart (inside the Reactor Building track bay) 3.3.3.4).

is< 5E-3 rem/hr (see H21C-114, Table 8.1-1 on page 67).

The total dose over the 7-day period is less than 1 rem, which is well below the generally accepted maximum for digital equipment, 1000 rem. The flow meter is commercial equipment and does not have a published radiation dose limit. ECP-17-00280-CN-001 H21C-114 is loaded in the NRC ePortal.

The selected instrument is designed for the expected flow rate, temperature and pressure for SAWA over the period of sustained operation.

Page 8 of 11

Nine Mile Point Nuclear Station, Unit 2 Seventh Six-Month Status Report for Implementation of HCVS Phases 1 and 2 SAWA Flow Instrument Expected SAWA Qualification Parameter Range

-2 to 544 GPM 100 to 300 GPM

-4 to 140 °F 50 to 120 °F 740 PSI MAX 365 PSI MAX The above flow instrument information is taken from vendor manual NOB035001NDREC001, "M-Series Electromagnetic Flow Meter, pages 44 and 45 loaded in the NRC ePortal for the 2.5-inch Badger Meter ModMAG M5000 flowmeter with 300# flanges specified for this application. The above ambient temperature range is based on information in the HCVS Phase 1 ECP 00087, previously uploaded to the ePortal in response to ISE Phase 1 Open Item 11. The maximum pressure of 365 psi is the FLEX pump shutoff head at maximum pump speed.

7 Interim Staff Evaluation Impacts There are no new ISE impacts that are in addition to those already described in the Fifth Six-Month status report. Refer to the Reference 12 Six-month status report for the previously described ISE impacts.

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.
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. ML133048836).

Page 9 of 11

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

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 2'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 (CENG) 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-13-109)," 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.

12. Nine Mile Point's Fifth 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 December 14, 2016 (RS-16-236).
13. 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 109), dated June 30, 2017 (RS-17-067).

Page 10of11

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

14. NRG letter to Exelon Generation Company, LLC, Nine Mile Point Nuclear Station, Unit 2 - Report for the Audit of Licensee Responses to Interim Staff Evaluation Open Items Related to NRC Order EA-13-109 to Modify License with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (CAC No. MF4482; EPID L-2014-JLD-004), dated October 17, 2017.

Page 11 of 11

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