RS-18-052, Report of Full Compliance with Phase 1 and Phase 2 of June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions

Report of Full Compliance with Phase 1 and Phase 2 of June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions

ML18159A142
Person / Time
Site:	Limerick
Issue date:	06/07/2018
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-109, RS-18-052
Download: ML18159A142 (20)

Text

Exelon Generation,.

RS-18-052 June 7, 2018 U.S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 1 Renewed Facility Operating License No. NPF-39 NRC Docket No. 50-352 Order No. EA-13-109

Subject:

Report of Full Compliance with Phase 1 and Phase 2 of 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. 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

3. NRC Interim Staff Guidance JLD-ISG-2015-01, "Compliance with Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," Revision O, dated 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. Limerick Generating Station, Units 1 and 2, Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109)," dated December 15, 2015

6. Exelon Generation Company, LLC, First Six-Month Status Report for Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated December 17, 2014

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

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 2

8. Exelon Generation Company, LLC Phase 1 (Updated) and Phase 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated December 15, 2015 (RS-15-301)

9. 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 1 O. Exelon Generation Company, LLC, Fifth Six-Month Status Report For Phases 1 and 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109) dated December 15, 2016

11. 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

12. Exelon Generation Company, LLC, Seventh Six-Month Status Report For Phases 1 and 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109) dated December 15, 2017

13. NRC letter to Exelon Generation Company, LLC, Limerick Generating Station, Units 1 and 2 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 1 of Order EA-13-109 (Severe Accident Capable Hardened Vents) (TAC Nos.

MF4418 and MF4419), dated April 1, 2015

14. NRC letter to Exelon Generation Company, LLC, Limerick Generating Station, Units 1 and 2 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 2 of Order EA-13-109 (Severe Accident Capable Hardened Vents) (TAC Nos.

MF4418 and MF4419), dated August 2, 2016

15. NRC letter to Exelon Generation Company, LLC, Limerick Generating Station, Units 1 and 2 - 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, dated May 29, 2018 On June 6, 2013, the Nuclear Regulatory Commission ("NRC" or "Commission") issued Order EA-13-109, "Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," (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 2 provided EGC's initial answer to the Order.

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 3 Reference 3 provided the NRC interim staff guidance on methodologies for compliance with Phases 1 and 2 of Reference 1 and endorsed industry guidance document NEI 13-02, Revision 1 (Reference 4) with clarifications and exceptions. Reference 5 provided the Limerick Generating Station, Unit 1 Phase 1 Overall Integrated Plan (OIP), which was replaced with the Phase 1 (Updated) and Phase 2 OIP (Reference 8). References 13 and 14 provided the NRC review of the Phase 1 and Phase 2 OIP, respectively, in an Interim Staff Evaluation (ISE).

Reference 1 required submission of a status report at six-month intervals following submittal of the OIP. References 6, 7, 8, 9, 1 O, 11, and 12 provided the first, second, third, fourth, fifth, sixth, and seventh six-month status reports, respectively, pursuant to Section IV, Condition 0.3, of Reference 1 for Limerick Generating Station, Unit 1.

The purpose of this letter is to provide the report of full compliance with Phase 1 and Phase 2 of the 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) (Reference 1) pursuant to Section IV, Condition 0.4 of the Order for Limerick Generating Station, Unit 1.

Limerick Generating Station, Unit 1 has designed and installed a venting system that provides venting capability from the wetwell during severe accident conditions in response to Phase 1 of NRC Order EA-13-109. Limerick Generating Station, Unit 1 has implemented a reliable containment venting strategy that makes it unlikely that the plant would need to vent from the containment drywall before alternative reliable containment heat removal and pressure control is reestablished in response to Phase 2 of NRC Order EA-13-109. The information provided herein documents full compliance for Limerick Generating Station, Unit 1 with NRC Order EA-13-109.

EGC's response to the NRC Interim Staff Evaluation (ISE) Phase 1 Open Items identified in Reference 13 have been addressed and closed as documented in Reference 12 and as described below, and are considered complete per Reference 15. The following table provides completion references for each OIP and ISE Phase 1 Open Item.

Reference 15 provides the results of the audit of ISE Open Item closure information provided in Reference 12. All Phase 1 and Phase 2 ISE Open Items are statused as closed as discussed in Reference 15.

There were no Phase 2 OIP Open Items.

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

01-2 Confirm that the Remote Operating Station (ROS) will be i11 Closed to ISE-3 an accessible areafollowinf? a Severe Accident (SA).

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 4 Combined Phase 1 and Phase 2 OIP Open Items Phase 1 Open Items 01-3 Determine wetwell line size to meet 1% venting criteria.

01-4 Confirm suppression pool heat capacity.

01-5 Determine the approach for combustible gases.

01-6 Provide procedures for HCVS Operation.

01-7 Verify the external pipi11g co11sists solely of large bore pipi11g and its supports have less than 300 square feet of cross section.

01-8 Evaluate drywell pressure indication for environmental qualifications to ensure this instrument can survive for 7 days after an event.

01-9 Determine Pe1formwzce Criteria for Motive gas Cylinders, Argon Cylinders, FLEX Diesel Generator, and FLEX (SA WA) pump pressure at 500 gpm.

01-10 Pe1form radiological evaluation for Phase 1 vent line impact on ERO response actions.

Status Closed to /SE-4 Closed to ISE-4 Closed to ISE-9 and ISE-10 Closed to ISE-13 Complete. (Reference EC 423331, Attachment 8 (formally known as ECR 16-0001 /)). EC 423331 is available in ePortal.

Unit 1 - Complete.

Unit 1 Pressure i11dicator will survive the environmental conditions for 7 days after the event. (See EC 423381 for replacement details).

EC 423381 is available in ePortal.

Unit 1 - Complete.

The pe1.for111ance criteria for the Motive Gas Cylinders, Argon Cylinder has been defined and the system will meet the requirements of the order.

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

EC 423381, and EC 423382 are available in ePortal.

See ISEP2-6for FLEX SAWA response.

Unit 1 - Complete.

The peak dose rates and 7-day integrated doses at operating stations, equipme11t locations, and along transit pathways required for sustai11ed operation of the HCVS have been calculated. The peak dose rates along potential operator transit pathways external to the Reactor Building are bounded by the peak dose rate outside the FLEX storaJ?e buildinJ?. ( Refere11ce

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 5 Combined Phase 1 and Phase 2 OIP Open Items Phase 1 Open Items Phase 1 Interim Staff Evaluation Open Items lSE-1 Make available for NRC staff audit documentation of a method to disable HCVS during normal operation to provide assurances against inadvertellt operation that also minimizes actions to enable HCVS operation following an ELAP.

lSE-2 Make available for NRC staff audit the final sizing evaluation for HCVS batteries/batte1y charger including inco1poration into FLEX DC loading calculation.

lSE-3 Make available for NRC staff audit all evaluation of temperature and radiological conditions to ensure that operating personnel call safely access alld operate controls and SUfJfJort equif)ment.

Status Calculation LM-0721 ).

Calculation LM-0721 is available in ePortal.

Status Unit 1 - Complete.

The system is designed to prevent inadvertent operation.

The flew control switch HS-057V-l 83 installed in the MCR panel 10-C689 is a key-lock switch. The switch is kept locked in "OFF" position (with key removed) to prevent inadvertent powering of the HCVS components from I 25 Vdc HCVS batte1y source.

Additionally, locked valves are used with the gas bottles to prevent inadvertent operation.

(Reference EC 423381 section 3.19).

EC 42338 I is available in ePortal.

Unit 1 - Complete.

The HCVS batteries have been sized to meet the requirements of the H CVS system and function for the initial 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> illto the event. (Reference Calculation LE-0128).

The FLEX diesel ge1Zerator loading is acceptable and rated loading of the FLEX diesel generator will llot be exceeded due to the additional HCVS loadillg. ( Referellce EC 423381 sectioll 3.35).

LE-0128 and EC 423381 are available in ePortal.

Unit I - Complete.

The primary operating station for HCVS operation is located in the Main Co1Ztrol Room. A

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 6 Phase 1 Interim Staff Evaluation Open Items ISE-4 Make available for NRC staff audit analyses demonstrating that HCVS has the capacity to vent the steam/energy equivalent of one percent of licensed/rated thermal power (unless a lower value is justified), and that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment desig11 pressure and the primmy containment pressure limit.

/SE-5 Make available for NRC staff audit the seismic and tornado missile final design criteriafor the HCVS stack.

Status remote operating station (ROS) is located in the EDG Corridor, EL. 217' (Room 313 ). The ROS location and travel path to ROS location were evaluated for habitability and accessibility during a severe accident. (Reference EC 423382 section 3.19).

EC 423382 is available in ePortal.

See Note 1 on page 15 for ROS temperature discussion.

Unit 1 - Complete.

The required one percent capacity at the lower of Primm)' Containment Pressure Limit or containment design pressure is verified using Reactor Excursion and Leak Analysis Program (RELAP). In oddition, Mod11/or Accident Analysis Program (MAAP) analyses are credited to verify that venting can be delayed for at least three hours and that anticipato1y venting can be credited to maintain Reactor Core isolation Cooling ( RCIC) functional.

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

EC 423382 and LM-709 are available in ePortal.

Unit 1 - Complete.

(Reference EC 423331 section 3.2, 3.5, 3.9, and 3.38 (formally known as 16-00011) and EC 423332 section 3.38 (formally known as 16-00012),

and EC 422831 section 3.24 (formally known as13-264))

describe seismic and tornado missile design criteria for HCVS stack. EC pkgs 423331,

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 7 Phase 1 Interim Staff Evaluation Open Items lSE-6 Make available for NRC staff audit the descriptions of local conditions (temperature, radiation and humidity) anticipated during ELAP and severe accident for the components (valves, instrumentation, sensors, tra11smitters, i11dicators, electro11ics, co11trol devices, etc.) required for HCVS ve11ting including confirmation that the compo11ents are capable of pe1forming their functio11s duri11g ELAP and severe accident conditions.

ISE-7 Make available for NRC staff audit documentation of the HCVS nitrogen pneumatic system design including sizing and location.

Status 423332, and 422831 are available in ePortal for review.

Unit 1 - Complete.

HCVS is designed to minimize the impact of elevated temperatures, due to the potential loss of ve11tilatio11, radiation and humidity impact on the ability of operators to initiate and maintain the functionality of the HCVS. The locations of system equipment that require operator action and the travel paths to reach the controls and indications are in mild environments.

(Reference EC 423382 section 3.19 and 3.24).

EC 423281 and EC 423382 are available in ePortal for review.

The loss of all gene ml area lighting, coincident with the ELAP, does not pose a threat to the operators' ability to access and operate HCVS, si11ce self-contained emergency lights illuminate the travel paths and hand held or portable lighting is available to manipulate HCVS equipment.

Unit 1 - Complete.

HCVS is designed to operate forfirst 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with installed independent pneumatic air supply, thereby eliminating the reliance on portable equipment. HCVS is also designed for 11111/tiple ve11ting and purge cycles during the first 24-hour period without the need to recharge pneumatic air supplies. The

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 8 Phase 1 Interim Staff Evaluation Open Items

/SE-8 Make available for NRC staff audit documentation that demonstrates adequate communication betwee11 the remote HCVS operation locations and HCVS decision makers during El.AP and severe accident conditions.

JSE-9 Provide a description of the final design of the HCVS to address hydrogen detonatio11 a11d deflagration.

Status pneumatic air supply is located in the emergency diesel corridor.

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

EC 423381 and Calculation LM-0723 are available in ePortal for review.

Unit 1 - Complete.

This communication method is the same as accepted in Order EA-12-049. These items will be powered and remain powered using the same methods as evaluated under EA-12-049 for the period of sustained operation, which may be longer than identified for EA-12-049.

Co111municatio11 will be via the plant radio system if available.

lf the radio system is not available, the Plant page system can be used. The page system was modified for FLEX to include a UPS that can be manually aligned to repower the system. (Reference AR 2492527-42). AR 2492527-42 is available in ePortal for review.

Unit 1 - Complete.

HCVS has been designed to ensure the flammability limits of gases passing through the system are not reached. A purge gas (argo11) supply system has been provided to displace pote11tially flammable/ detonable mixtures of gases that may be prese/tt in the vent after system actuation.

The purge gas supply system is designed for/our purge cycles durinR the first 24-hour period

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 9 Phase 1 Interim Staff Evaluation Open Items lSE-10 Provide a description of the strategies for hydrogen control that minimizes the potential for hydrogen gas migration and ingress into the reactor building or other buildings.

ISE-11 Make available for NRC staff audit documentation of a seismic qualification evaluation of HCVS components.

ISE-12 Make available for NRC staff audit descriptions of all instrumentation and controls (existing and planned) necessary to implement this order including qualification methods.

Status without the need to recharge.

(Reference EC 423381 section 3.19).

EC 423381 is available in ePortal for review.

Unit 1 - Complete.

As discussed in the December 2015 OlP, the Limerick wetwell vent line for each unit has a dedicated HCVS flowpathfrom the wetwell penetration to the outside with no interconnected system. The discharge point meets the guidance of "HCVS Release Point", HCVS-FAQ-04 (Reference 11 ).

Calculation LM-0709 is available in ePortal for review.

Unit 1-Complete.

Seismic documentation has been provided in EC 423381, Section 3.4, EC 423382, Section 3.4, and AR 2492527-

97.

EC 423381, EC 423382, and AR 2492527-97 are available in ePortalfor review.

Unit 1 - Complete.

EC 423381 installed and qualified the following components in the MCR and in the plant:

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

(Reference EC 423381 section 3.19 and 3.36).

Existing pressure instrument Pl-042-170-1 will be used to monitor containment pressure

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 10 Phase 1 Interim Staff Evaluation Open Items lSE-13 Make available for NRC staff audit the procedures for HCVS operation.

Status in the d1ywell. The transmitter (PT-042-170) has been replaced with an RC 1.97 qualified component to ensure this will remain functioning during the event. See EC 423381 for replacement and EC 423382 section 3. 19 for qualification of the component.

EC 423381 and EC 423382 are available in ePortalfor review.

Unit l - Complete.

Reference the following procedures.

SAMP-1: RPV Control SAM P-2: Containment and Radioactivity Release Control T-101: RPV Control T-l 02: Primwy Containment Control SPIT, SP/L, PC!P, DWIT, PCIH T-341: Pri111w)' Contai11111ent Venting Via Hardened Containment Vent System.

These procedures are in ePortal for review.

EGC's response to the NRC ISE Phase 2 Open Items identified in Reference 14 have been addressed and closed as documented in this submittal and are considered complete per Reference 15. The following table provides completion references for each ISE Phase 2 Open Item.

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

meeting reasonable protection from tornado missiles is Per Drawing HBD-842-01, at least 30 feet above the highest grade within 300 HCVS pipe leaves the yards.

protected structure more than I 20 feet above grade elevation, which is 217 feet MSL, as indicated on site topographical drawing C-0062 that shows grade elevation referenced to MSL within 300 vards of the HCVS components

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 11 Phase 2 Interim Staff Evaluation Open Items ISEP2-2 Licensee to confirm through analysis the temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment.

ISEP2-3 Licensee to evaluate the SA WA equipment and controls, as well as the ingress and egress paths for the expected severe accident conditions (temperature, humidity, radiation) for the sustained operatinR period.

Status evaluated.

Unit I - Complete.

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

For actions within the Reactor Building and between I and 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br />, evaluation of expected temperatures and dose rates has been pe1for111ed and determined them to be acceptable. (Reference EC 622673, and calculations L/\\1-0721 and LM-0725).

For locations outside the Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days, limerick pe1formed evaluations for the temperature and radiological conditions for the equipment and deployment locations, including ingress/egress paths and determined them to be acceptable. (Reference EC 622673, and calculations LM-0721 and LM-0725). EC 622673, LM-0721 and LM-0725 are available in ePortal for review.

See Note I on page I 5 for ROS temperature discussion.

Unit I - Complete.

Equipment and Controls Plant instrumentationfor

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 12 Phase 2 Interim Staff Evaluation Open Items ISEP2-4 Licensee to demonstrate that containment failure as a result of overpressure can be prevented without a drywell vent during severe accident conditions.

Status SA WA/SA WM that is qualified to RG 1.97 or equivalent is considered qualified for the sustained operating period without further evaluation.

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

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

SA WA/SA WM flow instrument SA WA/SA WM/FLEX pump SA WA/SA WM/FLEX generator Active valves in SA WAflm1*

path.

Ingress and Egress For locations outside the Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days when SAWA is being utilized, Limerick pe1formed evaluations of expected temperatures, humidity and the dose rates and determined them to be acceptable. (Reference EC 622673, and calculations LM-0721 and LM-0725).

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

Unit 1 - Complete.

The wetwell vent has been designed and installed to meet NE/ I 3-02 Rev 1 guidance, which will ensure that it is

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 13 Phase 2 Interim Staff Evaluation Open Items JSEP2-5 licensee shall demonstrate how the plant is bounded by the reference plant analysis that shows the SA WM strategy is successf ul in making it unlikely that a drywell vent is needed.

Status adequately sized to prevent containment overpressure under severe accident conditions.

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

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

Therefore, containment over pressurization is prevented without the need for a drywell

\\lent.

Unit 1 - Complete.

Using Figure 2.1. C from the combined Phases 1 and 2 OJ P, compare the reference plant parameters to the plant specific parameters.

Reference LGS Plant Torus Suppression freeboard Pool volume is free board 525,000 volume is gallons 147,670ft3

( 1, 104,572 f?allons)

SAWAflow SAWAflow is is500GPM 500 GPM at at 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> 8 hours followed by followed by JOO GPM JOOGPM from 12 from 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> to hours to 168

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 14 Phase 2 Interim Staff Evaluation Open Items JSEP2-6 ISEP2-7 Licensee to demonstrate that there is adequate communication between the MCR and the operator at the FLEX pump during severe accident conditions.

Licensee to demonstrate the SA WM flow instrumentation qualification for the expected environmental conditions Status I 168 hours0.00194 days <br />0.0467 hours <br />2.777778e-4 weeks <br />6.3924e-5 months <br /> I hours I

The above parameters for LGS compared to the reference plant that determine success of the SA WM strategy demonstrate that the reference plant values are bounding.

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

Unit 1 - Complete.

This communication method is the same as accepted in Order EA-12-049. These items will be powered and remain powered using the same methods as evaluated under EA-12-049 for the period of sustained operation, which may be longer than identified for EA-12-049.

Communication will be via the plant radio system if available.

If the radio system is not available, the Plant page system can be used. The page system was modified for FLEX to include a UPS that can be manually aligned to repower the system. (Reference AR 2492527-42)

Unit 1 - Complete.

For locations outside the Reactor Building between 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> and 7 days when SA WA is being utilized, Limerick Generating Station pe1for111ed evaluation of expected temperatures, humidity and the dose rates and determined them to be acceptable.

(Reference EC 622673 ).

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 15 Phase 2 Interim Staff Evaluation Open Items Note 1:

Status SAWA Pump Expected Flow SAWA Instrument Parameter Qualification Ran1~e 37 to 1246 JOO to 500 GPM GPM 32 to 140 °F 32 to 95 °F fluid fluid temperature temperature 14 to 122 °F Otol00 °F Instrument Ambient air Electro11icsf2J te1111Jeratu re 275 PSI 239.7 PSI 111axi11111111 111axi11111 m flJ Below 14 °F, the LCD may become sluggish or unresponsive; however, it will continue to measure and function to at least -4 °F.

(Reference MS2500-DataSheet).

MS2500-DataSheet and EC 622673 are available in ePortalfor review.

For the location of the ROS in the DG corridor, there is a maximum expected temperature of 121 °F.

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

The performance validation for T-341 to align the HCVS for operation determined the longest duration of 16 minutes in the EOG corridor would be required to align the system. Activation of the system included opening the argon and air bottles and repositioning a three-way valve. This would be the longest duration of any operator at the ROS during the event. If required, operating personnel working in high temperature areas will be protected using SA-AA-111, Heat Stress Control. With the use of SA-AA-111 heat stress controls, it is reasonable to assume the operator actions required to implement the HCVS and SAWA/SAWM strategies can be accomplished. SA-AA-111 and the validation study are available in ePortal.

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 16 MILESTONE SCHEDULE - ITEMS COMPLETE Limerick Generating Station, Unit 1 - Phases 1 and 2 Specific Milestone Schedule Target Comments Milestone Completion Activity Status Date Phases 1 and 2 HCVS Milestone Table Submit Overall Integrated Plan Jun 2014 Complete Submit 6 Month Updates Update 1 Dec 2014 Complete Update 2 Jun 2015 Complete Update 3 [Simultaneous with Phase 2 Dec 2015 Complete OIP]

Update 4 Jun 2016 Complete Update 5 Dec 2016 Complete Update 6 Jun 2017 Complete Update 7 Dec 2017 Complete Phase 1 Specific Milestones Phase 1 Modifications Hold preliminary/conceptual design Jun 2014 Complete meeting Unit 1 Modifications Evaluation Feb 2018 Complete Unit 1 Design Engineering On-Feb 2018 Complete site/Complete Unit 1 Implementation Outage Apr2018 Complete Unit 1 Walk Through Apr2018 Complete Demonstration/Functional Test Phase 1 Procedure Changes Active Unit 1 Operations Procedure Changes Feb 2018 Complete Developed

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 17 Target Milestone Completion Date Activity Status Phases 1 and 2 HCVS Milestone Table Unit 1 Site Specific Maintenance Feb 2018 Complete Procedure Developed Unit 1 Procedure Changes Active Apr2018 Complete Phase 1 Training Unit 1 Training Complete Feb 2018 Complete Phase 1 Completion Unit 1 HCVS Implementation Apr2018 Complete Phase 2 Specific Milestones Phase 2 Modifications Hold preliminary/conceptual design Jun 2016 Complete meeting Modifications Evaluation Mar 2018 Complete Unit 1 Design Engineering On-Feb 2018 Complete site/Complete Unit 1 Implementation Outage Apr2018 Complete Unit 1 Walk Through Apr2018 Complete Demonstration/Functional Test Phase 2 Procedure Changes Active Unit 1 Operations Procedure Changes Feb 2018 Complete Developed Unit 1 Site Specific Maintenance Feb 2018 Complete Procedure Developed Unit 1 Procedure Changes Active Apr2018 Complete Phase 2 Training Unit 1 Training Complete Feb 2018 Complete Phase 2 Completion Unit 1 HCVS Implementation Apr2018 Complete Submit Unit 1, Phase 1 & Phase 2, Completed with this Completion Report [60 days after Unit 1 Jun 2018 compliance]

submitial Comments Moved to align with actual completion date

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 18 ORDER EA-13-109 COMPLIANCE ELEMENTS

SUMMARY

The elements identified below for Limerick Generating Station, Unit 1, Phase 1 and Phase 2 OIP response submittal (Reference 5), and the 6-Month Status Reports (References 6, 7, 8, 9, 10, 11, and 12), demonstrate compliance with NRC Order EA-13-109. The Limerick Generating Station, Units 1 and 2 Final Integrated Plan for reliable hardened containment vent Phase 1 and Phase 2 strategies will be provided upon full compliance for Limerick Generating Station, Unit 2 (Spring 2019).

HCVS PHASE 1 AND PHASE 2 FUNCTIONAL REQUIREMENTS AND DESIGN FEATURES - COMPLETE The Limerick Generating Station, Unit 1, Phase 1 HCVS provides a vent path from the wetwell to remove decay heat, vent the containment atmosphere, and control containment pressure within acceptable limits. The Phase 1 HCVS will function for those accident conditions for which containment venting is relied upon to reduce the probability of containment failure, including accident sequences that result in the loss of active containment heat removal capability during an extended loss of alternating current power.

The Limerick Generating Station, Unit 1, Phase 2 HCVS provides a reliable containment venting strategy that makes it unlikely that the plant would need to vent from the containment drywell before alternative reliable containment heat removal and pressure control is reestablished. The Limerick Generating Station, Unit 1, Phase 2 HCVS strategies implement Severe Accident Water Addition (SAWA) with Severe Accident Water Management (SAWM) as an alternative venting strategy. This strategy consists of the use of the Phase 1 wetwell vent and SAWA hardware to implement a water management strategy that will preserve the wetwell vent path until alternate reliable containment heat removal can be established.

The Limerick Generating Station, Unit 1, Phase 1 and Phase 2 HCVS strategies are in compliance with Order EA-13-109. The modifications required to support the HCVS strategies for Limerick Generating Station, Unit 1 have been fully implemented in accordance with the station processes.

HCVS PHASE 1 AND PHASE 2 QUALITY STANDARDS - COMPLETE The design and operational considerations of the Phase 1 and Phase 2 HCVS installed at Limerick Generating Station, Unit 1 complies with the requirements specified in the Order and described in NEI 13-02, Revision 1, "Industry Guidance for Compliance with Order EA-13-109". The Phase 1 and Phase 2 HCVS has been installed in accordance with the station design control process.

The Phase 1 and Phase 2 HCVS components including piping, piping supports, containment isolation valves, containment isolation valve actuators and containment isolation valve position indication have been designed consistent with the design basis of

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 19 the plant. All other Phase 1 and Phase 2 HCVS components including electrical power supply, valve actuator pneumatic supply and instrumentation have been designed for reliable and rugged performance that is capable of ensuring Phase 1 and Phase 2 HCVS functionality following a seismic event.

HCVS PHASE 1 AND PHASE 2 PROGRAMMATIC FEATURES-COMPLETE Storage of portable equipment for Limerick Generating Station, Unit 1 Phase 1 and Phase 2 HCVS use provides adequate protection from applicable site hazards. Identified paths and deployment areas will be accessible during all modes of operation and during severe accidents, as recommended in NEI 13-02, Revision 1, Section 6.1.2.

Training in the use of the Phase 1 and Phase 2 HCVS for Limerick Generating Station, Unit 1 has been completed in accordance with an accepted training process as recommended in NEI 13-02, Revision 1, Section 6.1.3.

Operating procedures for Limerick Generating Station, Unit 1 have been developed and integrated with existing procedures to ensure safe operation of the Phase 1 and Phase 2 HCVS. Procedures have been verified and are available for use in accordance with the site procedure control program. Maintenance procedures for Limerick Generating Station, Unit 1 have been developed or have open tracking mechanisms created so that the procedures will be issued prior to being required. Limerick Generating Station, Unit 1 has implemented operation, testing, and inspection requirements for the HCVS and SAWA that follows the existing plant procedures and process to ensure reliable operation of the systems. The existing plant maintenance program will be applied to the HCVS and SAW A valves, instead of the maintenance frequency that has been listed in NEI 13-02, Section 6.2.4. The maintenance program uses PCM (Performance Centered Maintenance) template which is currently used to maintain the plant's safety related and non-safety related systems.

Site processes have been established to ensure the Phase 1 and Phase 2 HCVS is tested and maintained as recommended in NEI 13-02, Revision 1, Sections 5.4 and 6.2.

Limerick Generating Station, Unit 1 has completed validation in accordance with industry developed guidance to assure required tasks, manual actions and decisions for HCVS strategies are feasible and may be executed within the constraints identified in the HCVS Phases 1and2 OIP for Order EA-13-109 (Reference 5).

Limerick Generating Station, Unit 1 has completed evaluations to confirm accessibility, habitability, staffing sufficiency, and communication capability in accordance with NEI 13-02, Sections 4.2.2 and 4.2.3.

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

U.S. Nuclear Regulatory Commission Report of Full Compliance with Order EA-13-109 June 7, 2018 Page 20 I declare under penalty of perjury that the foregoing is true and correct. Executed on the 7th day of June 2018.

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

Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region I NRC Senior Resident Inspector - Limerick Generating Station NRC Project Manager, NRR - Limerick Generating Station Mr. Peter J. Bamford, NRR/JLD/JOMB, NRC Mr. Brian E. Lee, NRR/JLD/JCBB, NRC Mr. Rajender Auluck, NRR/JLD/JCBB, NRC Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Resources R. R. Janati, Chief, Division of Nuclear Safety, Pennsylvania Department of Environmental Protection, Bureau of Radiation Protection