NL-14-0844, Units 1 and 2, Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Requirements for Reliable Hardened Containment Vents (EA-13-109)

Units 1 and 2, Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Requirements for Reliable Hardened Containment Vents (EA-13-109)

ML14178B464
Person / Time
Site:	Hatch
Issue date:	06/27/2014
From:	Pierce C Southern Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-109, NL-14-0844
Download: ML14178B464 (53)

Text

Charles R. Pierce Southern Nuclear Regulatory Affairs Director Operating Company, Inc.

40 Inverness Center Parkway Post Office Box 1295 Birmingham, AL 35201 Tel 205.992.7872 Fax 205.992.7601 sou June 27, 2014 Docket Nos.: 50-321 NL-14-0844 50-366 U. S. Nuclear Regulatory Commission ATIN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant- Units 1 and 2 Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Requirements for Reliable Hardened Containment Vents (EA-13-1 09)

References:

1. NRC Generic Letter 89-16, Installation of a Hardened Wetwell Vent

2. NRC Order Number EA-12-050, Order Modifying Licenses with Regard to Requirements for Reliable Hardened Containment Vents , dated March 12, 2012.

3. NRC Order Number EA-13-1 09, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated June 6, 2013.

4. NEI 13-02 Revision 0, Industry Guidance for Compliance with Order EA-13-109, BWR Mark I & II Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated November 2013.

5. NRC Interim Staff Guidance JLD-ISG-2013-02, Compliance with Order EA-13-1 09, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions ,

Revision 0, dated November 14, 2013.

Ladies and Gentlemen:

On June 6, 2013, the NRC staff issued Reference 3 to all operating Boiling-Water Reactor licensees with Mark I and Mark II Containments. This Order required those licensees 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 the loss of active containment heat removal capability while maintaining the capabil ity to operate under severe accident (SA) conditions resulting from an Extended Loss of AC Power (ELAP). Specific requirements are outlined in of Reference 3.

Reference 3 requires submission of an Overall Integrated Plan (OIP) by June 30, 2014 for Phase 1 of the Order. The interim staff guidance (Reference 4) was issued November 14, 2013 which provides direction regarding the content of this OIP. The purpose of this letter is to provide the OIP for Phase 1 of the Order pursuant to Section IV, Condition D.1 , of Reference 3. This letter confirms that

U.S. Nuclear Regulatory Commission NL-14-0844 Page2 Southern Nuclear Operating Company (SNC) has received Reference 4 and has a Phase 1 OIP for the Edwin I. Hatch Nuclear Plant (HNP) Units 1 and 2. This OIP complies with the guidance for the purpose of ensuring the functionality of a HCVS to remove decay heat from the containment, and maintain control of containment pressure within acceptable limits following events that result in the loss of active containment heat removal capability while maintaining the capability to operate under SA conditions resulting from an ELAP as described in Attachment 2 of Reference 3.

Reference 4, Section 7.0 contains the specific reporting requirements for the OIP.

For the purposes of compliance with Phase 1 of Order EA-13-1 09, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, SNC plans to install a severe accident capable wetwell vent for HNP Units 1 and 2. Compliance with the requirements of Reference 3 supersedes any and all actions or commitments associated with References 1 and 2.

By submittal of this Phase 1 OIP in accordance with Reference 3, any actions or commitments made relative to Reference 1 or 2 are rescinded and not binding.

Six month progress reports will be provided consistent with the requirements of Order EA-13-109. As provided in Reference 3,Section IV, Condition D.2, SNC intends to submit to the NRC an OIP for compliance with the Phase 2 requirements described in Attachment 2 by December 31, 2015.

The letter does not contain any new NRC commitments. If you have any questions, please contact John Giddens at 205.992.7924.

Mr. C.R. Pierce states he is the Director of Regulatory Affairs of Southern Nuclear Operating Company, is authorized to execute this oath on behalf of Southern Nuclear Operating Company and, to the best of his knowledge and belief, the facts set forth in this letter are true.

Respectfully submitted, c4 .

C.R. Pierce Regulatory Affairs Director

...~...:- ~... *

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CRP/JMG

Enclosure:

Hatch Hardened Containment Venting System (HCVS)

Phase 1 Overall Integrated Plan Sworn to and subscribed before me this ~day of .J~ '2014.

CiL~~ Notary Public My commission expires:

U.S. Nuclear Regulatory Commission NL-14-0844 Page3 cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Best, Executive Vice President & Chief Nuclear Officer Mr. D. R. Vineyard, Vice President - Hatch Mr. D. R. Madison, Vice President - Fleet Operations Mr. B. J. Adams, Vice President- Engineering Mr. B. L. lvey, Vice President- Regulatory Affairs RType: CHA02.004 U.S. Nuclear Regulatory Commission Mr. V. M. McCree, Regional Administrator Mr. R. E. Martin, NRR Senior Project Manager- Hatch Mr. E. D. Morris, Senior Resident Inspector- Hatch State of Georgia Mr. J. H. Turner, Environmental Director Protection Division

Edwin I. Hatch Nuclear Plant - Units 1 and 2 Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Requirements for Reliable Hardened Containment Vents (EA-13-109)

Enclosure Hatch Hardened Containment Venting System (HCVS)

Phase 1 Overall Integrated Plan

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Table of Contents:

Part 1: General Integrated Plan Elements and Assumptions Part 2: Boundary Conditions for Wet Well Vent Part 3: Boundary Conditions for Dry Well Vent Part 4: Programmatic Controls, Training, Drills and Maintenance Part 5: Implementation Schedule Milestones Attachment 1: HCVS Portable Equipment Attachment 2: Sequence of Events Attachment 3: Conceptual Sketches Attachment 4: Failure Evaluation Table Attachment 5: References Attachment 6: Changes/Updates to this Overall Integrated Implementation Plan Attachment 7: List of Overall Integrated Plan Open Items HCVS Phase I OIP Page 1 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Introduction In 1989, the NRC issued Generic Letter 89-16, "Installation of a Hardened Wetwell Vent," to all licensees of BWRs with Mark I containments to encourage licensees to voluntarily install a hardened wetwell vent. In response, licensees installed a hardened vent pipe from the wetwell to some point outside the secondary containment envelope (usually outside the reactor building).

Some licensees also installed a hardened vent branch line from the drywell.

On March 19,2013, the Nuclear Regulatory Commission (NRC) Commissioners directed the staff per Staff Requirements Memorandum (SRM) for SECY 0157 to require licensees with Mark I and Mark II containments to "upgrade or replace the reliable hardened vents required by Order EA-12-050 with a containment venting system designed and installed to remain functional during severe accident conditions." In response, the NRC issued Order EA-13-109, Issuance of Order to Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accidents, June 6, 2013. The Order (EA-13-109) requires that licensees of BWR facilities with Mark I and Mark II containment designs ensure that these facilities have a reliable hardened vent to remove decay heat from the containment, and maintain control of containment pressure within acceptable limits following events that result in the 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).

The Order requirements are applied in a phased approach where:

• "Phase 1 involves upgrading the venting capabilities from the containment wetwell to provide reliable, severe accident capable hardened vents to assist in preventing core damage and, if necessary, to provide venting capability during severe accident conditions." (Completed "no later than startup from the second refueling outage that begins after June 30, 2014, or June 30, 20 18, whichever comes first.")

• "Phase 2 involves providing additional protections for severe accident conditions through installation of a reliable, severe accident capable drywell vent system or the development of a reliable containment venting strategy that makes it unlikely that a licensee would need to vent from the containment drywell during severe accident conditions." (Completed "no later than startup from the first refueling outage that begins after June 30, 2017, or June 30, 2019, whichever comes first.")

The NRC provided an acceptable approach for complying with Order EA-13-109 through Interim Staff Guidance (JLD-ISG-2013-02) issued in November 2013. The ISG endorses the compliance approach presented in NEI 13-02 Revision 0, Compliance with Order EA-13-109, Severe Accident Reliable Hardened Containment Vents, with clarifications. Except in those cases in which a licensee proposes an acceptable alternative method for complying with Order EA 109, the NRC staff will use the methods described in this ISG (NEI 13-02) to evaluate licensee compliance as presented in submittals required in Order EA-13-109.

The Order also requires submittal of an overall integrated plan which will provide a description of how the requirements of the Order will be achieved. This document provides the Overall HCVS Phase I OIP Page 2 of49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Integrated Plan (OIP) for complying with Order EA-13-109 using the methods described in NEI 13-02 and endorsed by NRC JLD-ISG-2013-02. Six month progress reports will be provided consistent with the requirements of Order EA-13-109.

The Plant venting actions for the EA-13-109 severe accident capable venting scenario can be summarized by the following:

• The HCVS will be initiated via manual action from the Main Control Room (MCR) or Remote Operating Station (ROS) at the appropriate time based on procedural guidance in response to plant conditions from observed or derived symptoms.

• The vent will utilize Containment Parameters of Pressure, Level and Temperature from the MCR instrumentation to monitor effectiveness of the venting actions

• The vent operation will be monitored by HCVS valve position, temperature and effluent radiation levels.

• The HCVS motive force will be monitored and have the capacity to operate for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> with installed equipment. Replenishment of the motive force will be by use of portable equipment once the installed motive force is exhausted.

• Venting actions will be capable of being maintained for a sustained period of up to 7 days or a shorter time if justified.

HCVS Phase I OIP Page 3 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assum~tions Extent to which the guidance, JLD-ISG-2013-02 and NEI 13-02, are being followed. Identify any deviations.

Include a description of any alternatives to the guidance. A technical justification and basis for the alternative needs to be provided. This will likely require a pre-meeting with the NRC to review the alternative.

Ref: JLD-ISG-2013-02 Compliance will be attained for E.I. Hatch Units 1&2 (Plant Hatch) with no known deviations to the guidelines in JLD-ISG-2013-02 and NEI 13-02 for each phase as follows :

• Phase I (wetwell): by the startup from the second refueling outage that begins after June 30, 2014, or June 30, 2018, whichever comes first. Currently scheduled for 1st Quarter 2017 (Unit 2), 1st Quarter 2018 (Unit 1)

Phase 2: Later If deviations are identified at a later date, then the deviations will be communicated in a future 6 month update following identification.

State Applicable Extreme External Hazard from NEI 12-06, Section 4.0-9.0 List resultant determination of screened in hazards from the EA-12-049 Compliance.

Ref: NEI 13-02 Section 5.2.3 and D.1.2 The following extreme external hazards screen-in for Plant Hatch

• Seismic, Extreme Cold- Ice Only, High Wind, Extreme High Temperature The following extreme external hazards screen out for Plant Hatch

• External Flooding, Extreme Cold except for Ice Key Site assumptions to implement NEI 13-02 HCVS Actions.

Provide key assumptions associated with implementation of HCVS Phase 1 Actions Ref: NEI 13-02 Section 1 Mark 1/II Generic HCVS Related Assumptions:

Applicable EA-12-049 assumptions:

049-1. Assumed initial plant conditions are as identified in NEI 12-06 section 3.2.1.2 items 1 and 2 049-2. Assumed initial conditions are as identified in NEI 12-06 section 3.2.1.3 items 1, 2, 4 , 5, 6 and 8 049-3. Assumed reactor transient boundary conditions are as identified in NEI 12-06 section 3.2.1.4 items 1, 2, 3 and 4 HCVS Phase I OIP Page 4 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions 049-4. No additional events or failures are assumed to occur immediately prior to or during the event, including security events except for failure of RCIC or HPCI. (Reference NEI 12-06, section 3.2.1.3 item 9) 049-5. At Time=O the event is initiated and all rods insert and no other event beyond a common site ELAP is occurring at any or all of the units. (NEI 12-06, section 3.2.1.3 item 9 and 3.2.1.4 item 1-4) 049-6. At 48 minutes (time critical at a time greater than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />) an ELAP is declared and actions begin as defined in EA 049 compliance 049-7. DC power and distribution can be credited for the duration determined per the EA-12-049 (FLEX) methodology for battery usage, (greater than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> with a calculation limiting value of 13.35 hrs.) (NEI 12-06, section 3.2.1.3 item 8) 049-8. Deployment resources are assumed to begin arriving at hour 6 and fully staffed by 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> 049-9. All activities associated with plant specific EA-12-049 FLEX strategies that are not specific to implementation of the HCVS , including such items as debris removal, communication, notifications, SFP level and makeup, security response, opening doors for cooling, and initiating conditions for the event, can be credited as previously evaluated for FLEX.

Applicable EA-13-1 09 generic assumptions:

109-1. Site response activities associated with EA-13-109 actions are considered to have no access limitations associated with radiological impacts while RPV level is above 2/3 core height (core damage is not expected).

109-2. Portable equipment can supplement the installed equipment after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> provided the portable equipment credited meets the criteria applicable to the HCVS . An example is use of FLEX portable air supply equipment that is credited to recharge air lines for HCVS components after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The FLEX portable air supply used must be demonstrated to meet the "SA Capable" criteria that are defined in NEI 13-02 Section 4.2.4.2 and Appendix D Section D.l.3.

109-3. SFP Level is maintained with either on-site or off-site resources such that the SFP does not contribute to the analyzed source term (Reference HCVS-FAQ-07) 109-4. Existing containment components design and testing values are governed by existing plant containment criteria (e.g., Appendix J) and are not subject to the testing criteria from NEI 13-02 (reference HCVS-FAQ-05 and NEI 13-02 section 6.2.2).

109-5. Classical design basis evaluations and assumptions are not required when assessing the operation of the HCVS. The reason this is not required is that the order postulates an unsuccessful mitigation of an event such that an ELAP progresses to a severe accident with ex-vessel core debris which classical design basis evaluations are intended to prevent.

(Reference NEI 13-02 section 2.3.1).

109-6. HCVS manual actions that require minimal operator steps and can be performed in the postulated thermal and radiological environment at the location of the step(s) (e.g. , load stripping, control switch manipulation, valving-in nitrogen bottles) are acceptable to obtain HCVS venting dedicated functionality. (reference HCVS-FAQ-01)

HCVS Phase I OIP Page 5 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions 109-7. HCVS dedicated equipment is defined as vent process elements that are required for the HCVS to function in an ELAP event that progresses to core melt ex-vessel. (reference HCVS-FAQ-02 and White Paper HCVS-WP-01) 109-8. Use of MAAP Version 4 or higher provides adequate assurance of the plant conditions (e.g.,

RPV water level, temperatures, etc.) assumed for Order EA-13-109 BDBEE and SA HCVS operation. (reference FLEX MAAP Endorsement ML13190A201) Additional analysis using RELAP5/MOD 3, GOTHIC, PCFLUD, LOCADOSE and SHIELD are acceptable methods for evaluating environmental conditions in areas of the plant provided the specific version utilized is documented in the analysis. Upper drywell temperatures will be determined as part of Phase 2 evaluation and guidance development.

109-9. Utilization of NRC Published Accident evaluations (e.g. SOARCA, SECY-12-0157, and NUREG 1465) as related to Order EA-13-109 conditions are acceptable as references.

(reference NEI 13-02 section 8) 109-10. Permanent modifications installed or planned per EA-12-049 are assumed implemented and may be credited for use in EA-13-109 Order response.

109-11. This Overall Integrated Plan is based on Emergency Operating Procedure changes consistent with EPG/SAGs Revision 3 as incorporated per the sites EOP/SAMG procedure change process.

109-12. Under the postulated scenarios of order EA-13-109 the Control Room is adequately protected from excessive radiation dose per General Design Criterion (GDC) 19 in 10CFR50 Appendix A and no further evaluation of its use as the preferred HCVS control location is required. (reference HCVS-FAQ-01) In addition, adequate protective clothing and respiratory protection is available if required to address contamination issues.

Plant Specific HCVS Related Assumptions/Characteristics:

HNP-1. The main stack at Plant Hatch can handle the HCVS flow from both units simultaneously.

Once outside the reactor building, effluent lines slope downward toward main stack such that effluent is unlikely to accumulate and create a hot spot.

HNP-2. All load stripping is accomplished within one hour and fifteen minutes of event initiation and will occur below the core area at locations not impacted by a radiological event.

HNP-3 . The rupture disc will be manually breached within 7.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> of event initiation if required for anticipatory venting during an ELAP.

HNP-4. All load stripping activities performed are located in the control building either at lower elevations (EL 130) or in the MCR.

HNP-5. The Plant layout of buildings and structures are depicted in the following figures 1-1, 1-2 and 1-3. Note the Main Control Room is located on the turbine deck elevation. The Control Building has substantial structural walls and features independent of the Reactor Building.

The vent routing is indicated on figure 1-1.

HCVS Phase I OIP Page 6 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions N~

Plant E. I. Hatch Map of Protected Area and Surrounding Area U2 ...&: S Figure 1-1 Plant Hatch Site Layout HCVS Phase I OIP Page 7 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions

@I] ri.O Unit 1 Electrical

<*\Tidalkln..:r Ij,OO~ I IJU c*M<J*'"""~'

Figure 1-2 Figure 1-3 Hatch Reactor Building Elevation View Hatch Control Building Ground Floor (EL 130)

HCVS Phase I OIP Page 8 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Provide a sequence of events and identify any time or environmental constraint required for success including the basis for the constraint.

HCVS Actions that have a time constraint to be successful should be identified with a technical basis and a justification provided that the time can reasonably be met (for example, action to open vent valves).

HCVS Actions that have an environmental constraint (e.g. actions in areas of High Thermal stress or High Dose areas) should be evaluated per guidance.

Describe in detail in this section the technical basis for the constraints identified on the sequence of events timeline attachment.

See attached sequence of events timeline (Attachment 2)

Ref: EA-13-109 Section 1.1.1, 1.1.2, 1.1.3 I NEI 13-02 Section 4.2.5, 4.2.6, 6.1.1 The operation of the HCVS will be designed to minimize the reliance on operator actions in response to hazards listed in Part 1. Immediate operator actions will be completed by plant personnel and will include the capability for remote-manual initiation from the HCVS control station. A list of the remote manual actions performed by plant personnel to open the HCVS vent path can be found in the following table (2-1 ). The reliable operation of HCVS will be met because HCVS meets the seismic requirements identified in NEI 13-02 and will be powered by DC buses with motive force supplied to HCVS valves from installed accumulators and portable nitrogen storage bottles. A HCVS Extended Loss of AC Power (ELAP) Failure Evaluation table, which shows alternate actions that can be performed, is included in Attachment 4.

Table 2-1 HCVS Remote Manual Actions Primary Action Primary Location I Notes Component

1. Isolate Standby Gas Hand switches located in the or at the Remote Treatment System (SGTS) by MCR Operating Station closing inlet valve 1/2T48- (ROS), depending on F081 and outlet isolation where operator of valves 1T46-F005 & 2T46- HCVS is stationed F002A & F002B

2. Disable PCIV interlocks by Panels in MCR containing PCIV Installing electrical jumpers for interlocks PCIVs (ref. Procedures 31 EO-EOP-1 01-1 and 31 EO-EOP-101-2)

3. Confirm closed HCVS Hand switch located in the MCR Unit 2 only.

condensate drain valve 2T 48- for condensate drain valve Unit 1 N/A F085 And at ROS panel

4. Breach the rupture disc by Manual hand wheels for valves Not required during openinq the arqon cylinder at the argon bottle and at the SA event Only HCVS Phase I OIP Page 9 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent valve & valve 1/2T48-F407 piping at the argon bottle station required if performing early venting for FLEX

5. Close argon cylinder valve & Manual hand wheels for valves Not required during valve 1/2T48-F407 at the argon bottle and at the SA event Only piping at the argon bottle station required if performing early venting for FLEX

6. Open Wetwell PCIVs 1/2T48- Hand switches located in the And at ROS F318 & 1/2T48-F326 MCR

7. Open HCVS vent control valve Hand switch for valve in the And at ROS 1/2T48-F082 MCR

8. Align power supplies for all Instruments and controls Prior to depletion of valves and instruments via located in the MCR or Control station batteries ,

Inverters 1/2R44-S006 & Building actions will be 1/2R44-S007 . required to swap to dedicated HCVS power supply.

And at ROS

9. Replenish pneumatics with Nitrogen bottles will be located Prior to depletion of replaceable nitrogen bottles in an area that is accessible to the pneumatic operators , preferably near the sources actions will ROS . be required to connect back-up sou rces at a time greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> .

10. Re-align power supplies for all Instruments and controls Prior to depletion of valves and instruments via located in the MCR or Control the installed power Inverters 1/2R44-S006 & Building sources actions will 1/2R44-S007. be required to connect back-up sources at a time greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

And at ROS A timeline was developed to identify required operator response times and potential environmental constraints. This timeline is based upon the following three cases:

1. Case 1 is based upon the action response times developed for FLEX when utilizing anticipatory venting in a BDBEE without core damage.

2. Case 2 is based on a SECY-12-0157 long term station blackout (LTSBO) (or ELAP) with HCVS Phase I OIP Page 10 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent failure of RCIC after a black start where failure occurs because of subjectively assuming over injection.

3. Case 3 is based on NUREG-1935 (SOARCA) results for a prolonged SBO (or ELAP) with the loss of RCIC case without black start.

Discussion of time constraints identified in Attachment 2 for the 3 timeline cases identified above

• At 7.3 Hours, initiate use of Hardened Containment Vent System (HCVS) per site procedures to maintain containment parameters below design limits and within the limits that allow continued use of RCIC for mitigation in a BDBEE -- The reliable operation of HCVS will be met because HCVS meets the seismic requirements identified in NEI 13-02 and will be powered by DC buses with motive force supplied to HCVS valves from installed accumulators and portable nitrogen storage bottles. Critical HCVS controls and instruments associated with containment will be DC powered and operated from the MCR or a Remote Operating Station on each unit. The DC power for HCVS will be available as long as the HCVS is required. Station batteries will provide power for greater than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, HCVS battery capacity will be available to extend past 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. In addition, when available Phase 2 FLEX Diesel Generator (DG) can provide power before battery life is exhausted. Thus initiation of the HCVS from the MCR or the Remote Operating Station within 7.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> is acceptable because the actions can be performed any time after declaration of an ELAP (1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br />) until the venting is needed at 7.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> for BDBEE venting. This action can also be performed for SA HCVS operation which occur at a time further removed from an ELAP declaration as shown in Attachment 2.

• At 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, based on battery depletion, the power supply will be swapped from station batteries to dedicated HCVS batteries to ensure power to the inverters. The DC power for HCVS will be available as long as the HCVS is required. Station batteries will provide power for greater than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, HCVS battery capacity will be available to extend past 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. In addition, when available, Phase 2 FLEX Diesel Generator (DG) can provide power before battery life is exhausted. A power monitor will be available at the MCR or ROS to dictate when transfer from the Station Batteries to the dedicated HCVS battery capacity is needed. Margin will be established such that the HCVS dedicated battery capacity exceeds 14 hours1.62037e-4 days <br />0.00389 hours <br />2.314815e-5 weeks <br />5.327e-6 months <br />.

• At 24 Hours, temporary generators will be installed and connected to the pigtail to power up battery chargers using a portable DG to supply power to HCVS critical components/instruments; time critical at a time greater than 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br /> (>12 hour Station Battery life plus >14 hour dedicated HCVS battery capacity). Current battery (station service plus dedicated HCVS) durations are calculated to last greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. DG will be staged beginning at approximately 8-10 hour time frame (Reference FLEX OIP). Within Two (2) hours later the DG will be in service. Thus the DGs will be available to be placed in service at any point after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> as required to supply power to HCVS critical components/instruments. DGs will be maintained in on-site FLEX storage buildings. DGs will be transferred and staged via haul routes and staging areas evaluated for impact from external hazards applicable to Plant Hatch.

HCVS Phase I OIP Page 11 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Modifications will be implemented to facilitate the connections and operational actions required to supply power within 10 hours1.157407e-4 days <br />0.00278 hours <br />1.653439e-5 weeks <br />3.805e-6 months <br /> which is acceptable because the actions can be performed any time after declaration of an ELAP until the repowering of the station service batteries is needed at greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

• At >24 hours installed nitrogen bottles will be valved-in to supplement the air accumulator tanks. The nitrogen bottles (three provided) can be replenished one at a time leaving the other 2 supplying the HCVS. This can be performed at any time prior to depletion of the accumulators which is expected to last greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> assuming a minimum of 12 HCVS cycles. Thus 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> ensures adequate capacity is maintained so this time constraint is not limiting.

• At >24 hours, the dedicated HCVS power supplies will be swapped from the dedicated HCVS batteries to the normal configuration powered by portable DGs. Margin will be established such that the total HCVS battery capacity exceeds 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />.

Discussion of radiological and temperature constraints identified in Attachment 2

• At <7.3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />, the rupture disc will be manually breached using the argon tank station in the reactor building. This is not an environmental constraint because the breaching of the rupture disc is not required for events where anticipatory venting at a value less than PSP (Pressure Suppression Pressure)/PCPL (Primary Containment Pressure Limit) is initiated since the rupture set point will be changed in response to NRC Order EA-12-049 to a value less than or equal to PSP.

• At 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, based on battery depletion, power supply will be swapped from station batteries to dedicated HCVS batteries to ensure power to the inverters. Access to the transfer switch will be in the control building which is separated from the Reactor Building by substantial walls and air space (refer to figure 1-1).

[OPEN ITEM 1: Determine location of dedicated HCVS battery transfer switch]

• At >24 hours, installed nitrogen bottles will be valved-in to supplement the air accumulator supply as stated for the related time constraint item. Nitrogen bottles and manual tie-in valve will be located in an area that is accessible to operators the Control Building or yard area.

[OPEN ITEM 2: Determine location of back-up nitrogen bottles]

• At >24 Hours, temporary generators will be installed and connected to the pigtail to power up battery chargers using a portable DG to supply power to HCVS critical components/instruments

- Time critical at a time greater than 25 hours2.893519e-4 days <br />0.00694 hours <br />4.133598e-5 weeks <br />9.5125e-6 months <br />. Current battery durations are calculated to last greater than 26 hours3.009259e-4 days <br />0.00722 hours <br />4.298942e-5 weeks <br />9.893e-6 months <br />. DG will be staged beginning at approximately 8-10 hour time frame.

Within Two (2) hours of deployment the DG will be in service. Thus the DGs will be available to be placed in service at any point after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> as required to supply power to HCVS critical components/instruments. The connections, location of the DG and access for refueling will be located in an area that is accessible to operators in the Control Building or in the yard area because the HCVS vent pipe is underground once it leaves the Reactor Building.

HCVS Phase I OIP Page 12 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent

[OPEN ITEM 3: Evaluate location of QOrtable DG for accessibility under Severe Accident HCVS use]

• At >24 hours, power suppl y will be swapped back to the normal configuration from the dedicated HCVS batteries. Access to the connections and location switch will be in the control building.

Provide Details on the Vent characteristics Vent Size and Basis (EA-13-109 Section 1.2.1 I NEI 13-02 Section 4.1.1l What is the plants licensed power? Discuss any plans for possible increases in licensed power (e.g. MUR, EPU).

What is the nominal diameter of the vent pipe in inches/ Is the basis determined by venting at containment design pressure, Primary Containment Pressure Limit (PCPL), or some other criteria (e.g. anticipatory venting)?

Vent Cae.aci~ (EA-13-109 Section 1.2.1 I NEI 13-02 Section 4.l.Jl Indicate any exceptions to the I % decay heat removal criteria, including reasons for the exception. Provide the heat capacity of the suppression pool in terms of time versus pressurization capacity, assuming suppression pool is the injection source.

Vent Path and Discharge (EA-13-109 Section 1.1.41 1.2.2 I NEI 13-02 Section 4.1.31 4.1.5 and Ae.e.endix FIG)

Provides a description of Vent path, release path, and impact of vent path on other vent element items.

Power and Pneumatic Sue.e.lr. Sources (EA-13-109 Sectionl.2.5 & 1.2.6 I NEI 13-02 Section 4.2.31 2.51 4.2.2 1 4.2.61 6.1)

Provide a discussion of electrical power requirements, including a description of dedicated 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> power supply from permanently installed sources. Include a similar discussion as above for the valve motive force requirements. Indicate the area in the plant from where the installed/dedicated power and pneumatic supply sources are coming Indicate the areas where portable equipment will be staged after the 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, the dose fields in the area, and any shielding that would be necessary in that area. Any shielding that would be provided in those areas Location o[Control Panels (EA-13-109 Section 1.1.11 1.1.21 1.1.31 1.1.41 1.2.411.2.5 I NEI 13-02 Section 4.1.31 4.2.21 4.2.314.2.51 4.2.61 6.1.1 and Ae.e.endix FIG)

Indicate the location of the panels, and the dose fields in the area during severe accidents and any shielding that would be required in the area. This can be a qualitative assessment based on criteria in NEI 13-02.

Hr.drogen (EA-13-109 Section 1.2.101 1.2.11 1 1.2.12 I NEI 13-02 Section 2.312.41 4.1.1 1 4.1.61 4.1.715.1 1 &

Ae.e.endix H)

State which approach or combination of approaches the plant will take to address the control offlammable gases, clearly demarcating the segments of vent svstem to which an approach applies HCVS Phase I OIP Page 13 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Unintended Cross Flow o(Vented Fluids (EA-13-109 Section1.2.3, 1.2.12 I NE1 13-02 Section 4.1.2. 4.1.4, 4.1.6 and Appendix H)

Provide a description to eliminate/minimize unintended cross flow of vented fluids with emphasis on interfacing ventilation systems (e.g. SGTS). What design features are being included t9limit leakage through interfacing valves or Appendix 1 type testing features?

Prevention o(InadvertentActuation (EA-13-109 Section 1.2.71NEI 13-02 Section 4.2.1)

The HCVS shall include means to prevent inadvertent actuation Component Qualifications (EA-13-109 Section 2.1 I NEI 13-02 Section 5.1. 5.3)

State qualification criteria based on use of a combination of safety related and augmented quality dependent on the location, function and interconnected system requirements Monitoring o(HCVS (Order Elements 1.1.4, 1.2.8, 1.2.91NEI 13-02 4.1.3, 4.2.2. 4.2.4. and Appendix FIG)

Provides a description of instruments used to monitor HCVS operation and effluent. Power for an instrument will require the intrinsically safe equipment installed as part of the power sourcing Component reliable and rugged performance (EA-13-109 Section 2.2 I NEI 13-02 Section 5.2. 5.3)

HCVS components including instrumentation should be designed, as a minimum, to meet the seismic design requirements of the plant.

Components including instrumentation that are not required to be seismically designed by the design basis of the plant should be designed for reliable and rugged performance that is capable of ensuring HCVS functionality following a seismic event. (reference ISG-JLD-2012-01 and ISG-JLD-2012-03 for seismic details.)

The components including instrumentation external to a seismic category 1 (or equivalent building or enclosure should be designed to meet the external hazards that screen-in for the plant as defined in guidance NEI 12-06 as endorsed by JLD-ISG-12-01 for Order EA-12-049.

Use of instruments and supporting components with known operating principles that are supplied by manufacturers with commercial quality assurance programs, such as IS09001. The procurement specifications shall include the seismic requirements and/or instrument design requirements, and specify the need for commercial design standards and testing under seismic loadings consistent with design basis values at the instrument locations.

Demonstration of the seismic reliability of the instrumentation through methods that predict performance by analysis, qualification testing under simulated seismic conditions, a combination of testing and analysis, or the use of experience data. Guidance for these is based on sections 7, 8, 9, and 10 of IEEE Standard 344-2004, "IEEE Recommended Practice for Seismic Qualification of Class IE Equipment for Nuclear Power Generating Stations, " or a substantially similar industrial standard could be used.

Demonstration that the instrumentation is substantially similar in design to instrumentation that has been HCVS Phase I OIP Page 14 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent previously tested to seismic loading levels in accordance with the plant design basis at the location where the instrument is to be installed (g-levels andfrequency ranges). Such testing and analysis should be similar to that performed for the plant licensing basis.

Vent Size and Basis The HCVS wetwell path is designed for venting steam/energy at a nominal capacity of 1% of 2804 MWt thermal power at pressure of 56 psig. This pressure is the lower of the containment design pressure (56 psig) and the PCPL value (62 psig) . The size of the wetwell portion of the HCVS is ~18 inches in diameter which provides adequate capacity to meet or exceed the Order criteria.

Vent Capacity .

The greater than 1% decay heat removal capacity at Plant Hatch assumes that the suppression pool pressure suppression capacity is sufficient to absorb the decay heat generated during the first 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />. The vent would then be able to prevent containment pressure from increasing above the containment design pressure. As part of the detailed design , the duration of suppression pool decay heat absorption capability will be confirmed.

[OPEN ITEM-4: Confirm suppression pool heat capacity]

Vent Path and Discharge The existing HCVS vent path at Hatch consists of a wetwell and drywell vent on each unit. The drywell vent exits the Primary Containment into the Reactor Building and proceeds down to the torus bay. Wetwell and drywell vent piping merges into a common header in the torus bay. Vent path for both wetwell and drywell exits the reactor building through an underground pipe. This pipe travels approximately 500 feet from both units and combines in a mixing chamber at the base of the main stack. All effluents exit out the main stack.

The HCVS discharge path uses the main stack.

Power and Pneumatic Supply Sources All electrical power required for operation of HCVS components will be routed through {two Inverters, one for each electrical division . These inverters will be sized at 7.5 kW each and will convert DC power from installed batteries into AC power for the end users (instruments, solenoid valves , etc.).

Battery power will be provided by the existing station service batteries for the first 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> following the ELAP event. At about 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />, power can be transferred to the HCVS dedicated batteries that will supply power for an additional time of > 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. At 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, power will transfer back to the normal configuration , at which time it is expected that FLEX generators will be in service to power the DC bus.

Pneumatic power for the HCVS air-operated valves (AOVs) is normally provided by the non-interruptible air system. Following an ELAP event, the non-interruptible air system is lost, and normal backup from installed nitrogen supply tanks is isolated. Therefore, for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, pneumatic force will be supplied from newly installed air accumulator tanks. These tanks will supply the required motive force to those HCVS valves needed to maintain flow through the HCVS effluent piping. After the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, backup nitrogen provided by nitrogen supply bottles will be manually_

HCVS Phase I OIP Page 15 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent valved-in and replenished as needed.

1. The HCVS flow path valves are air-operated valves (AOV) with air-to-open and spring-to-shut (i.e ., the wetwell containment isolation valves and the HCVS inlet isolation valve). Opening the valves requires energizing an AC powered solenoid operated valve (SOV) and providing motive air/gas. The detailed design will provide a permanently installed power source and motive air/gas supply adequate for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Beyond the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, FLEX generators will be used to maintain battery power to the HCVS components. The initial stored motive air/gas will allow for a minimum of twelve valve operating cycles for the HCVS valve for the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

2. Following the initial 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> period, additional motive force will be supplied from nitrogen bottles that will be staged at a gas cylinder rack located (near the ROS in the control building or outside) such that radiological impacts are not an issue. Additional bottles can be brought in as needed.

3. An assessment of temperature and radiological conditions will be performed to ensure that operating personnel can safely access and operate controls at the ROS based on time constraints listed in Attachment 2.

[OPEN ITEM 5: Determine location of HCVS Remote Operating Station (ROS) for both units.

Utilize HCVS-FAQ-01 in the response.]

4. All permanently installed HCVS equipment, including any connections required to supplement the HCVS operation during an ELAP (i.e., electric power, N2/air) will be located in areas reasonably protected from defined hazards listed in Part 1 of this report.

5. All valves required to open the flow path or valves that require manual operation to be closed to prevent diversion or cross-flow into other systems/units will be designed for remote manual operation following an ELAP, such that the primary means of valve manipulation does not rely on use of a hand wheel , reach-rod or similar means that requires close proximity to the valve (reference HCVS-FAQ-03) . Any supplemental connections will be pre-engineered to minimize man-power resources and address environmental concerns. Required portable equipment will be reasonably protected from screened in hazards listed in Part 1 of this OIP.

6. Access to the locations described above will not require temporary ladders or scaffolding .

Location of Control Panels The HCVS design allows initiating and then operating and monitoring the HCVS from the Main Control Room (MCR) or the Remote Operating Station (ROS). The MCR location is protected from adverse natural phenomena and is the normal control point for HCVS operation and Plant Emergency Response actions.

The final location of the ROS is still under evaluation at this time.

[OPEN ITEM 5: Determine location of HCVS Remote Operating Station (ROS) for both units.

Utilize HCVS-FAQ-01 in the response.]

HCVS Phase I OIP Page 16 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Hydrogen As is required by EA-13-1 09, Section 1.2.11, the HCVS must be designed such that it is able to either provide assurance that oxygen cannot enter and mix with flammable gas in the HCVS (so as to form a combustible gas mixture), or it must be able to accommodate the dynamic loading resulting from a combustible gas detonation. Several configurations are available which will support the former (e.g.,

purge, mechanical isolation from outside air, etc.) or the latter (design of potentially affected portions of the system to withstand a detonation relative to pipe stress and support structures).

[OPEN ITEM 6: State which approach or combination of approaches Plant Hatch decides to take to address the control of flammable gases.]

Unintended Cross Flow of Vented Fluids The HCVS uses the Primary Containment Isolation System (PCIS) containment isolation valves for containment isolation. These containment isolation valves are AOVs that are air-to-open and spring-to-shut. An SOV must be energized to allow the motive air to open the valve. Specifically:

• The PCIS control circuit will be used during all "design basis" operating modes including all design basis transients and accidents.

• Cross flow potential exists between the HCVS and the Standby Gas Treatment System (SGTS).

Resolution involves evaluation of SGTS isolation valve leakage for both inlet and outlet valves (referred to as boundary valves), as both interface with the HCVS. This evaluation will follow the testing criteria presented in NEI HCVS-FAQ-05. If necessary, these valves will be replaced with leak-tight valves. Testing and maintenance will be performed to ensure that the valves remain leak-tight.

[OPEN ITEM 7: Evaluate SGTS valve leakage utilizing criteria from NEI HCVS-FAQ-05.]

• An additional cross-flow avenue exists between the HCVS of the two units and other connected systems at the mixing chamber in the shared Main Stack. With the Main Stack being open to the atmosphere, there is no motive force to push effluent from the mixing chamber back to the plant, thus it is assumed this avenue of cross flow is not a reasonable assumption, since the buoyancy of the vent process fluid will not have sufficient motive force to create backflow in the mixing chamber Prevention of Inadvertent Actuation EOP/ERG operating procedures provide clear guidance that the HCVS is not to be used to defeat containment integrity during any design basis transients and accident. In addition, the HCVS will be designed to provide features to prevent inadvertent actuation due to a design error, equipment malfunction, or operator error such that any credited containment accident pressure (CAP) that would provide net positive suction head to the emergency core cooling system (ECCS) pumps will be available (inclusive of a design basis loss-of-coolant accident (DBLOCA)). However the ECCS pumps will not have normal power available because of the starting boundary conditions of an ELAP.

• The features that prevent inadvertent actuation are two PCIV's in series powered from different divisions, a rupture disk, or key lock switches. Procedures also provide clear guidance to not circumvent containment inteQrity by simultaneously opening torus and drywell HCVS Phase I OIP Page 17 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent vent valves during any design basis transient or accident. In addition, the HCVS will be designed to provide features to prevent inadvertent actuation due to a design error, equipment malfunction, or operator error.

Component Qualifications The HCVS components downstream of the second containment isolation valve and components that interface with the HCVS are routed in seismically qualified structures. For these components, the structures that are credited in Order EA-13-1 09 were analyzed for seismic ruggedness to ensure that any potential failure would not adversely impact the function of the HCVS or other safety related structures or components. HCVS components that directly interface with the pressure boundary will be considered safety related, as the existing system is safety related . The primary containment system limits the leakage or release of radioactive materials to the environment to prevent offsite exposures from exceeding the guidelines of 10CFR1 00. During normal or design basis operations, this means serving as a pressure boundary to prevent release of radioactive material.

Likewise, any electrical or controls component which interfaces with Class 1E power sources will be considered safety related up to and including appropriate isolation devices such as fuses or breakers, as their failure could adversely impact containment isolation and/or a safety-related power source.

The remaining components will be considered Augmented Quality. Newly installed piping and valves will be seismically qualified to handle the forces associated with the safe shutdown earthquake (SSE) back to their isolation boundaries. Electrical and controls components will be seismically qualified and will include the ability to handle harsh environmental conditions (although they will not be considered part of the site Environmental Qualification (EO) program).

HCVS instrumentation performance (e.g. , accuracy and precision) need not exceed that of similar plant installed equipment. Additionally, radiation monitoring instrumentation accuracy and range will be sufficient to confirm flow of radionuclides through the HCVS. The HCVS instruments, including valve position indication, process instrumentation , radiation monitoring, and support system monitoring, will be qualified by using one or more of the three methods described in the ISG, which includes:

1. Purchase of instruments and supporting components with known operating principles from manufacturers with commercial quality assurance programs (e.g. , IS09001) where the procurement specifications include the applicable seismic requirements, design requirements, and applicable testing.

2. Demonstration of seismic reliability via methods that predict performance described in IEEE 344-2004

3. Demonstration that instrumentation is substantially similar to the design of instrumentation previously qualified.

Instrument Qualification Method*

HCV8 Process Temperature 1809001 I IEEE 344-2004 I Demonstration HCV8 Process Radiation Monitor 1809001 I IEEE 344-2004 I Demonstration HCV8 Process Valve Position 1809001 I IEEE 344-2004 I Demonstration HCVS Phase I OIP Page 18 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent HCVS Pneumatic Supply Pressure IS09001 I IEEE 344-2004 I Demonstration HCVS Electrical Power Supply Availability IS09001 I IEEE 344-2004 I Demonstration

• The specific qualification method used for each required HCVS instrument will be reported in future 6 month status reports.

[OPEN ITEM 8: Identify qualification method used for HCVS instruments.]

Monitoring of HCVS The Plant Hatch wetwell HCVS will be capable of being manually operated during sustained operations from a control panel located in the MCR and will meet the requirements of Order element 1.2.4. The MCR is a readily accessible location with no further evaluation required. Control Room dose associated with HCVS operation conforms to GDC 19/Aiternate Source Term (AST).

Additionally, to meet the intent for a secondary control location of section 1.2.5 of the Order, a readily accessible Remote Operating Station (ROS) will also be incorporated into the HCVS design as described in NEI 13-02 section 4.2.2.1 .2.1. The controls and indications at the ROS location will be accessible and functional under a range of plant conditions , including severe accident conditions with due consideration to source term and dose impact on operator exposure, extended loss of AC power (ELAP) , and inadequate containment cooling. An evaluation will be performed to determine accessibility to the location , habitability, staffing sufficiency, and communication capability with Vent-use decision makers (EOP/SOP/SAMG) ..

[OPEN ITEM 9: Evaluate HCVS monitoring location for accessibility, habitability, staffing sufficiency, and communication capability with vent-use decision makers]

The wetwell HCVS will include means to monitor the status of the vent system in both the MCR and the ROS. Included in the existing design of the torus hardened vent (THV) are control switches in the MCR with valve position indication. These THV controls currently meet the environmental and seismic requirements of the Order for the plant severe accident and will be upgraded to address ELAP. Control and indication of the wetwell HCVS valves will be duplicated at the ROS. The ability to open/close these valves multiple times during the event's first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> will be provided by two air accumulator tanks and station service batteries, supplemented by installed backup battery power sources. Beyond the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, the ability to maintain these valves open or closed will be accomplished through the use of replaceable nitrogen bottles and FLEX generators.

The wetwell HCVS will include indications for vent temperature and effluent radiation levels at both the MCR and ROS. Other important information on the status of supporting systems, such as power source status and pneumatic supply pressure, will also be included in the design and located to support HCVS operation. The wetwell HCVS includes existing containment pressure and wetwell level indication in the MCR to monitor vent operation . This monitoring instrumentation provides the indication from the MCR as per Requirement 1.2.4 and will be designed for sustained operation during an ELAP event.

Component reliable and ruaaed oerformance HCVS Phase I OIP Page 19 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent The HCVS downstream of the second containment isolation valve, including piping and supports, electrical power supply, valve actuator pneumatic supply, and instrumentation (local and remote) components, will be designed/analyzed to conform to the requirements consistent with the applicable design codes (e.g. , Non-safety, Cat 1, SS and 300# ASME or 831.1, NEMA 4, etc.) for the plant and to ensure functionality following a design basis earthquake.

The torus hardened vent (THV) system was originally installed to satisfy the requirements of Generic Letter 89-16. The modifications associated with the THV vent were performed under the provisions of 10CFR50.59 and thus the Plant Hatch THV was designed, analyzed, and implemented consistent with the design basis of the plant. The current design will be evaluated to confirm that the existing system, coupled with current and planned modifications to upgrade the THV to a hardened containment vent system (HCVS), will meet the requirements of Order EA-13-1 09 and remain functional following a severe accident.

Additional modifications required to meet the Order will be reliably functional at the temperature, pressure, and radiation levels consistent with the vent pipe conditions for sustained operations. The instrumentation/power supplies/cables/connections (components) will be procured for use under the temperature, pressure, radiation level, total integrated dose radiation for the effluent vent pipe and HCVS ROS location.

Conduit design will be installed to Seismic Class 1 criteria. Both existing and new barriers will be used to provide a level of protection from missiles when equipment is located outside of seismically qualified structures. Augmented quality requirements will be applied to the components installed in response to this Order.

In addition to these design requirements, providing sufficient channel separation (by distance and/or protective barriers) will minimize the likelihood of a common cause event which adversely affects both divisions of the containment isolation valves when the control for these valves is provided at the ROS. Separation will be in accordance with Plant Hatch electrical design criteria (ref. RG 1.75 and IEEE 384).

If the instruments are purchased as commercial-grade equipment, they will be procured suitable to operate under severe accident environment as required by NRC Order EA-13-109 and the guidance of NEI 13-02. The equipment procurement will utilize the following guidance for seismic per IEEE 344, environment per IEEE 323, and Electromagnetic Compatibility (EMC) per RG 1.180. These qualifications will be bounding conditions for Plant Hatch. The qualification for the equipment by the supplier will be validated by SNC for the specific location at Plant Hatch to ensure that the bounding conditions envelope the specific plant conditions.

For the instruments required after a potential seismic event, the following methods will be used to verify that the design and installation is reliable I rugged and thus capable of ensuring HCVS functionality following a seismic event. Applicable instruments are rated by the manufacturer (or otherwise tested) for seismic impact at levels commensurate with those of postulated severe accident event conditions in the area of instrument component use using one or more of the following methods:

HCVS Phase I OIP Page 20 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent

• demonstration of seismic motion will be consistent with that of existing design basis loads at the installed location;

• substantial history of operational reliability in environments with significant vibration with a design envelope inclusive of the effects of seismic motion imparted to the instruments proposed at the location;

• adequacy of seismic design and installation is demonstrated based on the guidance in Sections 7, 8, 9, and 10 of IEEE Standard 344-2004, IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations, or a substantially similar industrial standard;

• demonstration that proposed devices are substantially similar in design to models that have been previously tested for seismic effects in excess of the plant design basis at the location where the instrument is to be installed (g-levels and frequency ranges);

• seismic qualification using seismic motion consistent with that of existing design basis loading at the installation location.

HCVS Phase I OIP Page 21 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS)Phase 1 Overall Integrated Plan Part 2 Boundary Conditions for WW Vent: BDBEE Venting Determine venting capability for BDBEE Venting, such as may be used in an ELAP scenario to mitigate core damage.

Ref: EA-13-1 09 Section 1.1.4/ NEI13-02 Section 2.2 First 24 Hour Coping Detail Provide a general description of the venting actions for first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> using installed equipment including station modifications that are proposed.

Ref: EA-13-109 Section 1.2.6/ NEI 13-02 Section 2.5, 4.2.2 The operation of the HCVS will be designed to minimize the reliance on operator actions for response to a ELAP and BDBEE hazards identified in part 1 of this OIP. Immediate operator actions can be completed by Operators from the HCVS control station(s) and include remote-manual initiation. The operator actions required to open a vent path are as described in table 2-1.

Remote-manual is defined in this report as a non-automatic power operation of a component and does not require the operator to be at or in close proximity to the component. No other operator actions are required to initiate venting under the guiding procedural protocol.

The HCVS will be designed to allow initiation, control, and monitoring of venting from the MCR the response to this Order. Both locations minimize plant operators' exposure to adverse temperature and radiological conditions and are protected from hazards assumed in Part 1 of this report.

Permanently installed power and motive air/gas capability will be available to support operation and monitoring of the HCVS for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. Permanently installed equipment will supply air and power to HCVS for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> before FLEX diesel generators will be required to be functional.

System control:

i. Active: PCIVs are operated in accordance with EOPs/SOPs to control containment pressure. The HCVS is designed for a minimum of 12 open/close cycles under ELAP conditions over the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following an ELAP, based on normal operating pressures. Controlled venting will be permitted in the revised EPGs and associated implementing EOPs, e.g., jumpers will be used to override the containment isolation circuit on the PCIVs needed to vent containment.

Passive: Inadvertent actuation protection is provided by the current containment isolation circuitry associated with the PCIVs used to operate the HCVS. In addition, the HCVS isolation valve is normally key-locked closed and has a rupture disc located downstream. This rupture disc has a burst set pressure above the header pressure expected during a design basis event. Breach of the rupture disc will occur outside of the MCR and will require manual operation.

Greater Than 24 Hour Coping Detail Provide a general description of the venting actions for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> using portable and installed equipment including station modifications that are proposed.

Ref: EA-13-109 Section 1.2.4, 1.2.8/ NEI 13-02 Section 4.2.2 HCVS Phase I OIP Page 22of49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2 Boundary Conditions for WW Vent: BDBEE Venting After approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, available personnel will be able to connect supplemental nitrogen to the HCVS, but based on the staged quantity of bottles this action is not expected to occur until after 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br />. Connections for supplementing electrical power and motive force required for HCVS will be located in accessible areas with reasonable protection from the hazards described in Part 1 of this report per NEI 12-06 that minimize personnel exposure to adverse conditions for HCVS initiation and operation. Connections will be pre-engineered quick disconnects or similar in order to minimize manpower resources. Sufficient nitrogen bottles will be staged to support operations for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following the ELAP event (less than 3 planned actuations for FLEX), additional bottles can be connected to support sustained operation. After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, power can be switched back to the normal configuration which is expected to be powered by FLEX generators.

These actions provide long term support for HCVS operation for the period beyond 24 hrs. to 7 days (sustained operation time period) because on-site and off-site personnel and resources will have access to the unit(s) to provide needed action and supplies.

Details:

Provide a brief description of Procedures I Guidelines:

Confirm that procedure/guidance exists or will be developed to support implementation.

Primary Containment Control Flowchart exists to direct Operations in protection and control of containment integrity, including use of the existing Hardened Vent System. Other site procedures for venting containment using the HCVS include: 31 EO-TSG-001-0, Technical Support Guidelines; 31 EO-EOP-101-1/2, Emergency Containment Venting; and, 31 EO-EOP-104-1/2, Primary Containment Venting for Hydrogen and Oxygen Control.

Identify modifications:

List modifications and describe how they support the HCVS Actions.

EA-12-049 Modifications

• Provide the Inverters that will convert station battery DC power into AC power for use by the end-users needed for HCVS operation.

• Provide both the air accumulators and the nitrogen bottles for pneumatic support of the HCVS air actuators for the first 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following an ELAP event.

• Provide a means to manually breach the rupture disc in the HCVS header to allow for flow.

EA-13-1 09 Modifications

• Install dedicated batteries and disconnect switches to supply power to HCVS for the second 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> following the ELAP event once station batteries have been depleted.

• Install a Remote Operation Station for both units.

• Install a HCVS Radiation Monitor and power supply on each unit.

• Install required HCVS instrumentation and controls in the MCR and ROS for both units required by the Order. Some of this will be completed under EA-12-049 (FLEX) modifications listed above (rupture disc instrumentation).

HCVS Phase I OIP Page 23 of49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2 Boundary Conditions for WW Vent: BDBEE Venting

• Additional modifications may be required to system isolation valves, rupture disk/assembly, and existing HCVS piping to facilitate testing requirements or comply with the effluent temperature requirements.

Key Venting Parameters:

List instrumentation credited for this venting actions. Clearly indicate which of those already exist in the plant and what others will be newly installed (to comply with the vent order)

Initiation, operation and monitoring of the HCVS venting will rely on the following key parameters and indicators:

Kev Parameter Component Identifier Indication Location HCVS Effluent temperature TBD MCR/ROS HCVS Pneumatic supply pressure TBD MCR/ROS HCVS valve position indication TBD MCR/ROS Rupture Disc Pressure 1/2T48-R030 Reactor Buildina Initiation and operation of the HCVS system will rely on several existing Main Control Room key parameters and indicators which are qualified or evaluated to the existing plant design (reference NEI 13-02 Section 4.2.2.1.9):

Kev Parameter Component Identifier Indication Location Drywall pressure 1/2T48-R608/R609 MCR Torus pressure 1/2T48-R608/R609 MCR Torus water temperature 1/2T47-R611/R612 MCR Torus level 1/2T48-R607AlB MCR Reactor pressure 1/2C32-R605A/B MCR Drvwell radiation 1/2T48-R601A/B MCR HCVS indications for HCVS pneumatic supply pressure and HCVS effluent temperature will be installed in the MCR to comply with EA-13-1 09.

Notes:

None HCVS Phase I OIP Page 24 of49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2 Boundary Conditions for WW Vent: Severe Accident Venting Determine venting capability for Severe Accident Venting, such as may be used in an ELAP scenario to mitigate core damage.

Ref: EA-13-109 Section 1.2.10 I NEI13-02 Section 2.3 First 24 Hour Coping Detail Provide a general description of the venting actions for first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> using installed equipment including station modifications that are proposed.

Ref: EA-13-109 Section 1.2.6/ NEI 13-02 Section 2.5, 4.2.2 The operation of the HCVS will be designed to minimize the reliance on operator actions for response to an ELAP and severe accident events. Severe accident event assumes that specific core cooling actions from the FLEX strategies identified in the response to Order EA-12-049 were unsuccessful and that core damage has occurred, up to and including a breach of the reactor vessel by molten core debris. Venting will occur without the need for manually breaching the rupture disc, since conditions in containment would be sufficient to burst the rupture disc without assistance from operators. Access to the reactor building will be restricted as determined by the RPV water level and core damage conditions. Immediate actions will be completed by Operators in the Main Control Room (MCR) or at the HCVS Remote Operating Station (ROS) and will include remote-manual actions from a local gas cylinder station. The operator actions required to open a vent path were previously listed in the BDBEE Venting Part 2 section of this report.

As stated in the section on BDBEE Venting, the HCVS will be designed to allow initiation, control, and monitoring of venting from the MCR and will be capable of operation from an ROS to be installed as part of the response to this Order. Both locations minimize plant operators' exposure to adverse temperature and radiological conditions and are protected from hazards assumed in Part (Table 2-1 of this document. Travel pathways will be reviewed for dose and temperature, and alternate routes may need to be considered to minimize operator exposure to harsh environmental conditions).

Permanently installed power and motive air/gas capable will be available to support operation and monitoring of the HCVS for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

System control:

i. Active: PCIVs are operated in accordance with EOPs to control containment pressure.

The HCVS is designed for a minimum of 12 open/close cycles of the isolation valve under ELAP conditions over the first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> following an ELAP. Controlled venting will be permitted in the revised EPGs. Jumpers will be used to override the containment isolation circuit on the PCIVs needed to vent containment.

ii. Passive: Inadvertent actuation protection is provided by the current containment isolation circuitry associated with the PCIVs used to operate the HCVS. In addition, the HCVS isolation valve is normally key-locked closed and has a rupture disc located downstream. This rupture disc has a burst set pressure above the header pressure expected during a design basis event.

HCVS Phase I OIP Page 25 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2 Boundary Conditions for WW Vent: Severe Accident Venting Greater Than 24 Hour Coping Detail Provide a general description of the venting actions for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> using portable and installed equipment including station modifications that are proposed.

Ref: EA-13-109 Section 1.2.4, 1.2.8/ NEI 13-02 Section 4.2.2 Connections for supplementing electrical power and motive force required for HCVS will be located in accessible areas with reasonable protection per Part 1 of this report. Connections will be pre-engineered quick disconnects or similar arrangement to minimize manpower resources.

After 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, power will be switched back to the normal configuration which is expected to be powered by SA Capable FLEX generators at that time (refer to Open Item 3).

After approximately 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, available personnel will be able to connect supplemental nitrogen to the HCVS if greater than 12 HCVS cycles have occurred or the pneumatic pressure is low. Sufficient nitrogen bottles will be staged to support operations for up to 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> following the ELAP event.

Specifics are the same as for BDBEE Venting Part 2 except {the location and refueling actions for the FLEX DG and replacement Nitrogen Bottles} will be evaluated for SA environmental conditions resulting from the proposed damaged Reactor Core and resultant HCVS vent pathway.

[OPEN ITEM 10: Perform SA Evaluation for FLEX DG use for post 24 hour2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> actions]

These actions provide long term support for HCVS operation for the period beyond 24 hrs. to 7 days (sustained operation time period) because on-site and off-site personnel and resources will have access to the unit(s) to provide needed action and supplies.

Details:

Provide a brief description of Procedures I Guidelines:

Confirm that procedure/guidance exists or will be developed to support implementation.

The operation of the HCVS is governed the same for SA conditions as for BDBEE conditions, except for the need to manually breach the rupture disk. Existing guidance in the SAMGs directs the plant staff to consider changing radiological conditions in a severe accident.

Identify modifications:

List modifications and describe how they support the HCVS Actions.

The same as for Part 2 BDBEE Venting Key Venting Parameters:

List instrumentation credited for the HCVS Actions. Clearly indicate which of those already exist in the plant and what others will be newly installed (to comply with the vent order)

HCVS Phase I OIP Page 26 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2 Boundary Conditions for WW Vent: Severe Accident Venting Initiation, operation and monitoring of the HCVS venting will rely on the following key parameters and indicators:

Kev Parameter Comoonent Identifier Indication Location HCVS effluent temperature TBD MCR!ROS HCVS pneumatic supply pressure TBD MCRIROS HCVS valve position indication TBD MCR!ROS HCVS power status TBD MCRIROS HCVS effluent radiation monitor TBD MCR!ROS Initiation, operation and monitoring of the HCVS system will rely on several existing Main Control Room key parameters and indicators that are the same as for BDBEE Venting Part 2.

HCVS indications for HCVS pneumatic supply pressure, HCVS power status, HCVS effluent temperature and HCVS effluent radiation will be installed in the MCR to comply with EA-13-1 09.

Notes:

None HCVS Phase I OIP Page 27 of49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2 Boundary Conditions for WW Vent: HCVS Support Equipment Functions

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• t* .;c?.If(i:.

Determine venting capability support functions needed Ref: EA-13-109 Section 1.2.8, 1.2.9/ NEI13-02 Section 2.5, 4.2.4, 6.1.2 BDBEE Venting Provide a general description of the BDBEE Venting actions support functions. Identify methods and strategy(ies) utilized to achieve venting results.

Ref: EA-13-109 Section 1.2.9/ NEI 13-02 Section 2.5, 4.2.2, 4.2.4, 6.1.2 Containment integrity is initially maintained by permanently installed equipment. All containment venting functions will be performed from the MCR or ROS except for breaching of the rupture disc for anticipatory venting, which is not required for BDBEE venting.

Venting will require support from DC power as well as instrument air systems as detailed in the response to Order EA-12-049. Existing safety related station service batteries will provide sufficient electrical power for HCVS operation for greater than 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Before station service batteries are depleted, portable FLEX diesel generators, as detailed in the response to Order EA-12-049, will be credited to charge the station service batteries and maintain DC bus voltage after 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />. Newly installed accumulator tanks with back-up portable N2 bottles will provide sufficient motive force for all HCVS valve operation and will provide for multiple operations of the 1/2T48-F082 vent valve.

Severe Accident Venting Provide a general description of the Severe Accident Venting actions support functions. Identify methods and strategy(ies) utilized to achieve venting results.

Ref: EA-13-109 Section 1.2.8, 1.2.9/ NEI 13-02 Section 2.5, 4.2.2, 4.2.4, 6.1.2 The same support functions that are used in the BDBEE scenario would be used for severe accident venting. To ensure power for the 12 to 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, a set of dedicated HCVS batteries will be available to feed HCVS loads via a manual transfer switch. At 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />, power will be switched back to the normal configuration powered by FLEX generators evaluated for SA capability.

Nitrogen bottles located outside of the reactor building and in the immediate area of the ROS will be available to tie-in supplemental pneumatic sources before the air accumulator tanks are depleted.

Details:

Provide a brief description of Procedures I Guidelines:

Confirm that procedure/guidance exists or will be developed to support implementation.

Most of the equipment used in the HCVS is permanently installed. The key portable items are the SA Capable/FLEX DGs and the nitrogen bottles needed to supplement the air supply to the AOVs after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. The nitrogen bottles will be permanently staged in the plant for use post event. The DGs and additional nitrogen bottles once deployed post event will remain in position for the duration of the event.

The staging and deployment of this equipment will be incorporated into new or existing procedures as part of the BDBEE!severe accident response.

Identify modifications:

List modifications and describe how they support the HCVS Actions.

HCVS Phase I OIP Page28 of49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2 Boundary Conditions for WW Vent: HCVS Support Equipment Functions EA-12-049 Modifications a1212licable to HCVS 012eration

• Provide connection points and cabling at the control building wall and turbine building (SW Corner) to connect FLEX 600VAC diesel generators to the 600 VAG Bus C and Bus D to provide power to the battery chargers and critical AC components after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

EA-13-1 09 Modification:

• Provide piping and connection points at a suitable location in the control building or outside to connect portable nitrogen bottles for motive force to HCVS components after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. HCVS connections required for portable equipment will be protected from all applicable screened-in hazards and located such that operator exposure to radiation and occupational hazards will be minimized. Structures to provide reasonable protection of the HCVS connections will be constructed to meet the requirements identified in NEI-12-06 section 11 for screened in hazards.

Key Support Equipment Parameters:

List instrumentation credited for the support equipment utilized in the venting operation. Clearly indicate which of those already exist in the plant and what others will be newly installed (to comply with the vent order)

Local control features of the FLEX DG electrical load and fuel supply. (part of EA-12-049 compliance)

Pressure gauge on supplemental nitrogen bottles, to be staged with Nitrogen bottles.

Notes: None HCVS Phase I OIP Page 29 of49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 2 Boundary Conditions for WW Vent: HCVS Venting Portable Equipment Deployment

-. *~ ; .

Provide a general description of the venting actions using portable equipment including modifications that are proposed to maintain and/or support safety functions.

Ref: EA-13-109 Section 3.1/NEI 13-02 Section 6.1.2, D.1.3.1 Deployment pathways for compliance with Order EA-12-049 are acceptable without further evaluation needed except in areas around the Reactor Building or in the vicinity of the HCVS piping. Deployment in the areas around the Reactor Building or in the vicinity of the HCVS piping will allow access, operation and replenishment of consumables with the consideration that there is potential Reactor Core Damage and HCVS operation.

Strategy Modifications Protection of connections Identify Actions including Identify modifications Identify how the connection is how the equipment will be protected deployed to the point of use.

Per compliance with Order N/A Per compliance with Order EA-12-049 EA-12-049 (FLEX) (FLEX)

Notes: Additional nitrogen bottles can be brought in after 72 hours8.333333e-4 days <br />0.02 hours <br />1.190476e-4 weeks <br />2.7396e-5 months <br /> for the valve motive force.

HCVS Phase I OIP Page 30 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 3: Boundar~ Conditions for Dr~ Well Vent Provide a sequence of events and identify any time constraint required for success including the basis for the time constraint.

HCVS Actions that have a time constraint to be successful should be identified with a technical basis and a justification provided that the time can reasonably be met (for example, a walk-through of deployment).

Describe in detail in this section the technical basis for the time constraint identified on the sequence of events timeline Attachment 2B See attached sequence of events timeline (Attachment 2B).

Ref: EA-13-109 Section X.X.X I NEI 13-02 Section X.X.x The initial response for a BDBEE/Severe Accident is to vent via the wetwell. When the wetwell becomes unusable then venting via the drywell will be available based on the original Generic Letter 89-16 design for Plant Hatch.

The rest of Part 3 will be completed with the Phase 2 OIP submittal by December 31, 2015 Severe Accident Venting Determine venting capability for Severe Accident Venting, such as may be used in an ELAP scenario to mitigate core damage.

Ref: EA-13-109 Section X.X.X I NEI13-02 Section X.X.x First 24 Hour Coping Detail Provide a general description of the venting actions for first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> using installed equipment including station modifications that are proposed.

Ref: EA-13-109 Section X.X.X I NEI 13-02 Section X.X.x Greater Than 24 Hour Coping Detail Provide a general description of the venting actions for greater than 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> using portable and installed equipment including station modifications that are proposed.

Ref: EA-13-109 Section X.X.X I NEI 13-02 Section X.X.x Details:

HCVS Phase I OIP Page 31 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 3: Boundarll Conditions for Drll Well Vent Provide a brief description of Procedures I Guidelines:

Confirm that procedure/guidance exists or will be developed to support implenuntation.

Identify modifications:

List modifications and describe how they support the HCVS Actions.

Key Venting Parameters:

List instrumentation credited for the venting HCVS Actions.

Notes:

HCVS Phase I OIP Page 32 of 49 Revision 0 06/23/ 14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 4: Programmatic Controls, Training, Drills and Maintenance Identify how the programmatic controls will be met.

Provide a description of the programmatic controls equipment protection, storage and deployment and equipment quality addressing the impact of temperature and environment Ref: EA-13-109 Section 3.1, 3.2 I NEI 13-02 Section 6.1.2, 6.1.3, 6.2 Program Controls:

The HCVS venting actions will include:

• Site procedures and programs are being developed in accordance with NEI 13-02 to address use and storage of portable equipment relative to the Severe Accident defined in NRC Order EA-13-109 and the hazards applicable to the site per Part 1 of this OIP.

• Routes for transporting portable equipment from storage location(s) to deployment areas will be developed as the response details are identified and finalized. The identified paths and deployment areas will be accessible during all modes of operation and during Severe Accidents.

Procedures:

Procedures will be established for system operations when normal and backup power is available, and during ELAP conditions.

The HCVS procedures will be developed and implemented following the plants process for initiating or revising procedures and/or guidelines will support existing symptom based command and control strategies in the current EOPs and will contain the following details:

• Appropriate conditions and criteria for use of the HCVS

• When and how to place the HCVS in operation,

• The location of system components,

• Instrumentation available ,

• Normal and backup power supplies,

• Directions for sustained operation, including the storage location of portable equipment,

• Training on operating the portable equipment, and

• Testing of portable equipment Licensees will establish provisions for out-of-service requirements of the HCVS and compensatory measures. The following provisions will be documented in a controlled document:

The provisions for out-of-service requirements for HCVS functionality are applicable in Modes 1, 2 and 3.

• If for up to 90 consecutive days, the primary or alternate means of HCVS operation are non-functional, no compensatory actions are necessary.

• If for up to 30 days, the primary and alternate means of HCVS operation are non-functional, no compensatory actions are necessary.

• If the out of service times exceed 30 or 90 days as described above, the following actions HCVS Phase I OIP Page 33 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 4: Programmatic Controls, Training, Drills and Maintenance will be performed:

o The condition will entered into the corrective action system, o The HCVS functionality will be restored in a manner consistent with plant procedures, o A cause assessment will be performed to prevent future loss of function for similar causes.

o Initiate action to implement appropriate compensatory actions

[OPEN ITEM 11: Determine the control document for HCVS out of service time criteria]

Describe training plan List training plans for affected organizations or describe the plan for training development Ref: EA-13-109 Section 3.2 I NEI 13-02 Section 6.1.3 Personnel expected to perform direct execution of the HVCS will receive necessary training in the use of plant procedures for system operations when normal and backup power is available and during ELAP conditions. The training will be refreshed on a periodic basis and as any changes occur to the HCVS. Training content and frequency will be established using the Systematic Approach to Training (SAT} process.

In addition, (reference NEI 12-06) all personnel on-site will be available to supplement trained personnel.

Identify how the drills and exercise parameters will be met.

Alignment with NEI 13-06 and 14-0las codified in NTTF Recommendation 8 and 9 rulemaking The Licensee should demonstrate use of the HCVS system in drills, tabletops, or exercises as follows:

• Hardened containment vent operation on normal power sources (no ELAP).

• During FLEX demonstrations (as required by EA-12-049: Hardened containment vent operation on backup power and from primary or alternate location during conditions of ELAP/loss of UHS with no core damage. System use is for containment heat removal AND containment pressure control.

• HCVS operation on backup power and from primary or alternate location during conditions of ELAP/loss of UHS with core damage. System use is for containment heat removal AND containment pressure control with potential for combustible gases (Demonstration may be in conjunction with SAG change).

Ref: EA-13-109 Section 3.1 I NEI 13-02 Section 6.1.3 HCVS Phase I OIP Page 34 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 4: Programmatic Controls, Training, Drills and Maintenance The site will utilize the guidance provided in NEI 13-06 and 14-01 for guidance related to drills, tabletops, or exercises for HCVS operation. In addition, the site will integrate these requirements with compliance to any rulemaking resulting from the NTTF Recommendations 8 and 9.

Describe maintenance plan:

• The HCVS maintenance program should ensure that the HCVS equipment reliability is being achieved in a manner similar to that required for FLEX equipment. Standard industry templates (e.g., EPRI) and associated bases may be developed to define specific maintenance and testing.

o Periodic testing and frequency should be determined based on equipment type, expected use and manufacturer's recommendations (further details are provided in Section 6 of this document).

o Testing should be done to verify design requirements and/or basis. The basis should be documented and deviations from vendor recommendations and applicable standards should be justified.

o Preventive maintenance should be determined based on equipment type and expected use.

The basis should be documented and deviations from vendor recommendations and applicable standards should be justified.

o Existing work control processes may be used to control maintenance and testing.

• HCVS permanent installed equipment should be maintained in a manner that is consistent with assuring that it performs its function when required.

o HCVS permanently installed equipment should be subject to maintenance and testing guidance provided to verify proper function.

• HCVS non-installed equipment should be stored and maintained in a manner that is consistent with assuring that it does not degrade over long periods of storage and that it is accessible for periodic maintenance and testing.

Ref: EA-13-109 Section 1.2.13 I NEI 13-02 Section 5.4, 6.2 The site will utilize the standard EPRI industry PM process (Similar to the Preventive Maintenance Basis Database) for establishing the maintenance calibration and testing actions for HCVS components. The control program will include maintenance guidance, testing procedures and frequencies established based on type of equipment and considerations made within the EPRI guidelines.

Plant Hatch will implement the following operation, testing and inspection requirements for the HCVS to ensure reliable operation of the system.

Table 4-1 : Testing and Inspection Requirements Description Frequency Cycle the HCVS valves and the interfacing Once per operating cycle system valves not used to maintain containment integrity during operations.

HCVS Phase I OIP Page 35 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 4: Programmatic Controls 2 Training 2 Drills and Maintenance Perform visual inspections and a walk down of Once per operating cycle HCVS components Test and calibrate the HCVS radiation Once per operating cycle monitors .

Leak test the HCVS. (1) Prior to first declaring the system functional; (2) Once every three operating cycles thereafter; and (3) After restoration of any breach of system boundary within the buildings Validate the HCVS operating procedures by Once per every other operating cycle conducting an open/close test of the HCVS control logic from its control panel and ensuring that all interfacing system valves move to their proper (intended) positions .

Notes:

Leak test the HCVS applies to the non-PCIV HCVS valves per section 6.2.3 of NEI13-02 an clarified by HCVS-FAQ-05 HCVS Phase I OIP Page 36 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 5: Milestone Schedule Provide a milestone schedule. This schedule should include:

• Modifications timeline

• Procedure guidance development complete 0 HCVS Actions 0 Maintenance

• Storage plan (reasonable protection)

• Staffing analysis completion

• Long term use equipment acquisition timeline

• Training completion for the HCVS Actions The dates specifically required by the order are obligated or committed dates. Other dates are planned dates subj ect to change. Updates will be provided in the periodic (six month) status reports.

Ref: EA-13-109 Section 0.1, 0.3 I NEI 13-02 Section 7.2.1 The following milestone schedule is provided. The dates are planning dates subject to change as design and implementation details are developed. Any changes to the following target dates will be reflected in the subsequent 6 month status reports .

Milestone Target Activity Comments Completion Status Date Submit Overall Integrated Implementation Plan Jun 2014 Complete Submit 6 Month Status Report Dec. 2014 Hold preliminary/conceptual design meeting Jun , 2015 Submit 6 Month Status Report Jun . 2015 Submit 6 Month Status Report Dec. 2015 Simultaneous with Phase 2 OIP U2 Design Engineering On-site/Complete Mar, 2016 Submit 6 Month Status Report Jun . 2016 Operations Procedure Changes Developed Dec, 2016 Site Specific Maintenance Procedure Developed Dec, 2016 Submit 6 Month Status Report Dec. 2016 Training Complete Dec, 2016 U2 Implementation Outage Feb,2017 Procedu re Changes Active Mar, 2017 U2 Walk Through Demonstration/Functional Test Mar, 2017 U1 Design Engineering On-site/Complete Mar, 2017 Submit 6 Month Status Report Jun. 2017 Submit 6 Month Status Report Dec. 201 7 U1 Implementation Outage Feb, 2018 U1 Walk Through Demonstration/Functional Test Mar, 2018 HCVS Phase I OIP Page 37 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Part 5: Milestone Schedule 1 Submit Completion Report May, 2018 1 1 I I HCVS Phase I OIP Page 38 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Attachment 1: HCVS Portable Egui~ment BDBEE Severe Accident Performance Criteria Maintenance I PM requirements List portable equipment Ventinf( Venting Argon Cylinders X N/A Check periodically for pressure, replace or replenish as needed Nitrogen Cylinders X X TBD Check periodically for pressure, replace or replenish as needed FLEX DG X X Commercial Grade DG evaluated to Per Response to EA-12-049 survive at location deployed for SA environment HCVS Phase I OIP Page 39 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Attachment 2: Sequence of Events Timeline Table 2A: Wet Well HCVS Timeline t " .5 m t = 1 hr t=O s RCIC ELAP SBO starts Declared Case 1 FLEX Successful Containment Venting Ref: HNP FLEX O IP t " 7 hrs Blow A11ticipatory (anticipato ry venting rupture d1sc V enting gene rator 111 not re p resented in No Injec tion place for FLEX No Injection S E CY 0 157}

and HCVS loads I I

I I

I I

Core

'IV Damage Level at TA F Case 2

• _ . . , - - -* - - - - - ** .....-----4~ RCIC L ate Failure t " 23 hrs t"' 24 hrs t., 34 hrs Ref: SECY-12-0157 I

Containment Ve nting t"' 11 hrs I I

(based on preventing Begin monitoring at MCR or ROS I I t,.. 24 hrs ex ceeding PCPL} HCVS pneumatic ancl battery status . I Replenishment of HCVS No replenishment expecte<l to b e I pow er and pneumatic required b efore t = 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> I I supplies I I I I I t "" 12 hrs I I I I Transfer to I I I HCVS Battery I Case 3 RCIC Early Failure t"" *1 hr t "' 2 hr t= 8 h rs t "" 11 h rs t"" 24 hrs Ref: SOARCA t"' 10 hrs t "' 12 hrs Legend

References:

Adequate co re cooling mai ntained C ase 1 : HNP FLEX Overall Integrated Plan Injection Lost Case 2 : S E CY 0157 - ML12344A030 Increased shine and lea kage of radionuclides p rimari ly fro m W etwell Case 3 : SOARCA - ML13150A053 HCVS Post Core Damage Dose Evaluation Required HCVS Time evaluation required I N ot to scale HCVS Phase I OIP Page 40 of 49 Revi sion 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Attachment 3: Conceptual Sketches Sketch 1: Electrical Layout of System (preliminary)

Sketch 2: P&ID Layout of HCVS (preliminary)

• Piping routing for vent path

• Demarcate the valves (in the vent piping) between the currently existing and new ones

• HCVS Instrumentation Process Flow Diagram Sketch 3: Plant Layout (later)

• Egress and Ingress Pathways to ROS, Battery Transfer Switch, DG Connections and Deployment location HCVS Phase I OIP Page 41 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Preliminary NOTE : DIV I POWER DI STRIB UTIO N OI V II

1. Normally open ki rk key in t erlock 125/ 25 0V DC SWGR 2A 125/ 250V DC SWGR 2B switch . Key is removable in open 2R22 - SOI 6 2R22 - SOI7 I DEOICATE~I T T position only. I DEDICATED DIV I BATTERIES BATTERIES Dl V II

2. Kirk key interlock switch ope ration is to be performed under AC 2R25-S03a I I)

AC 2R25-S037 adm inistrative con trol and during extended 580 only . T I)

) BKR I

) BKR 1

) I ~CR INVERTE~ I ALARM STATUS MCR INSTRUMENTATION I ~CR INVERTER AlARM STATUS

• Reactor Water Lev el

~'

• Reoctor Pre ss ur e

• Orywell Press ure ALT -<

• Orywell Tempe rature

<F- ALT CRITI CAL

• Torus Press u re INVERTER 2A

=

• Torus Water Level ER 2B J'

• Tor u s Water Tempe r ature 2RH- S006

• CST Water Level 5007 STATIC :nc

~TCH

• Orywell Wide Range Radiation H Monitor

-~- _____:---. I -~-  !----"""'-

-~-

_,........__ £ '_ f--~-

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,__ _,........__ -~- f - -,........_

,........__ ,-- !---,........_- 1---,........_

_,........__ 1---,........_

I MCR INSTRU MENTATION P6 5 7

,- 1---,........_- _____:---._ _~_.__,........__

- II I"HCVS Po,.,er Status I

2R25-S066 120V AC CRITI CAL 2 R25 - S067 120V AC CR!TICAL INST. CAB INET 2A I ST. CABINET 28 n--n 0 0 Nol es 1&2 Noles 1&2

'Hcvsva~* ca;;trOI 1 -120~---------,

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!HcVs Vai:"e Co~r~ ~d- - ~- - 12oVAC - - - - - - - I I Valve Po~ition Indication I ,I ...* ~.... *~**"* I ~* I 'I I

I I

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( .~UTURE)

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(BKR 2T48-F3 19

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1 I

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II I

I

~

(DKR 2)

L, 2T4B -

<~ FAAD

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I ( FUTURE )

120VAC 2T48 -

FOO l 2T48-F062 (BKR 15) 2T48 -

F066 2T4 8' F00 2B

+ 2T40- f F320

£lUll **

(BKR 17)

(2T48 -

F326 I

II I

L---------- --------- ~ !NSTRU

• HCVS Power Sta tu s L----------- --- -------- --~

...

• HCVS Pneumatic Supply 2R25 - S064 2R25-S065 I RE MOTE I.NSTRUMENTATI ON Pressure Indicator

• HCVS Effluent Temperature

• HCVS Radiation Monitor Display

• Drywell Pressure REMOT E

• Torus Pressure

• Tor u s Water Level

• Tor u :s Water Temperature l REMOTE OPERATING I I NSTRU M ENTATI ON

• HCVS Pneumatic Supply

• HCVS Va lve Po sition Indication I ~~~~Np1~~~} I Pressure Indicator

• HCVS Effluent Temperature l Inve r t e r s wi ll se r vice HCVS I

• Inv erter Status

• HCVS Radiation Monito r

• Reactor Pressure I a nd FLEX Loads REV. K 4

)

05 01 14 Sketch 1: Electrical Layout of System (Unit 2, Unit 1 similar)

Preliminary HCVS Phase I OIP Page 42 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Preliminary E'lT STACK NC FC

---

!_ __SGTS__

( HCVS)

HCVS Phase I OIP Page 43 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan

,--P-f_e_l_i_ffi

__ill_a_f_Y_--,1 Sketch 2: Layout of current HCVS, Unit2 (Unit1 similar)

HCVS Phase I OIP Page 44 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Attachment 4: Failure Evaluation Table Table 4A: Wet Well HCVS Failure Evaluation Table Failure with Alternate Action Functional Failure Impact on Containment Mode Failure Cause Alternate Action Venting?

Failure of Vent to Open Valves fail to open/close No action needed, power is already tied into No on Demand due to loss of normal AC station service battery via inverter for minimum power 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> Failure of Vent to Open Valves fail to open/close Connect dedicated batteries to inverter via No on Demand due to loss of alternate transfer switch for minimum 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> AC power (long term)

Failure of Vent to Open Valves fail to open/close Recharge station service batteries with FLEX No on Demand due to complete loss of provided generators, considering severe batteries (long term) accident conditions Failure of Vent to Open Valves fail to open/close No action needed , air can be supplied by No on Demand due to loss of normal accumulator tanks, which is sufficient for at pneumatic air supply least 12 cycles of F082 valve over first 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> .

Failure of Vent to Open Valves fail to open/close Tie-in nitrogen cylinders to air system No on Demand due to loss of alternate supporting HCVS valves, replace bottles as pneumatic air supply needed.

(long term)

Failure of Vent to Open Valves fail to open/close Heroic action needed Yes on Demand due to SOV failure HCVS Phase I OIP Page 45 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Attachment 5: References

1. Generic Letter 89-16, Installation of a Hardened Wetwell Vent, dated September 1, 1989

2. Order EA-12-049, Mitigation Strategies for Beyond-Design-Basis External Events, dated March 12, 2012

3. Order EA-12-050, Reliable Hardened Containment Vents , dated March 12, 2012

4. Order EA-12-051, Reliable SFP Level Instrumentation , dated March 12,2012

5. Order EA-13-1 09, Severe Accident Reliable Hardened Containment Vents, dated June 6, 2013

6. JLD-ISG-2012-01 , Compliance with Order EA-12-049, Mitigation Strategies for Beyond-Design-Basis External Events, dated August 29, 2012

7. JLD-ISG-2012-02, Compliance with Order EA-12-050, Reliable Hardened Containment Vents , dated August 29, 2012

8. JLD-ISG-2013-02, Compliance with Order EA-13-1 09, Severe Accident Reliable Hardened Containment Vents, dated November 14, 2013

9. NRC Responses to Public Comments, Japan Lessons-Learned Project Directorate Interim Staff Guidance JLD-ISG-2012-02:

Compliance with Order EA-12-050, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents, ADAMS Accession No. ML12229A477, dated August 29, 2012

10. NEI 12-06, Diverse and Flexible Coping Strategies (FLEX) Implementation Guide, Revision 1, dated August 2012 11 . NEI 13-02, Industry Guidance for Compliance with Order EA-13-1 09, Revision 0, Dated November 2013

12. NEI 13-06, Enhancements to Emergency Response Capabilities for Beyond Design Basis Accidents and Events, Revision 0, dated March 2014

13. NEI 14-01 , Emergency Response Procedures and Guidelines for Extreme Events and Severe Accidents , Revision 0, dated March 2014

14. NEI HCVS- FAQ-01 , HCVS Primary Controls and Alternate Controls and Monitoring Locations

15. NEI HCVS-FAQ-02, HCVS Dedicated Equipment

16. NEI HCVS-FAQ-03, HCVS Alternate Control Operating Mechanisms

17. NEI HCVS-FAQ-04, HCVS Release Point

18. NEI HCVS-FAQ-05, HCVS Control and 'Boundary Valves'

19. NEI HCVS-FAQ-06, FLEX Assumptions/HCVS Generic Assumptions

20. NEI HCVS-FAQ-07, Consideration of Release from Spent Fuel Pool Anomalies

21. NEI HCVS-FAQ-08, HCVS Instrument Qualifications

22. NEI HCVS-FAQ-09, Use of Toolbox Actions for Personnel

23. NEI White Paper HCVS-WP-01, HCVS Dedicated Power and Motive Force

24. NEI White Paper HCVS-WP-02, HCVS Cyclic Operations Approach HCVS Phase I OIP Page 46 of 49 Revision 0 06/23/14

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan

25. NEI White Paper HCVS-WP-03, Hydrogen/CO Control Measures

26. NEI White Paper HCVS-WP-04, FLEX/HCVS Interactions

27. IEEE Standard 344-2004, IEEE Recommended Practice for Seismic Qualification of Class 1E Equipment for Nuclear Power Generating Stations,

28. Edwin I. Hatch EA-12-049 (FLEX) Overall Integrated Implementation Plan, Rev 0, February 2013

29. Edwin I. Hatch EA-12-050 (HCVS) Overall Integrated Implementation Plan, Rev 0, February 2013

30. Edwin I. Hatch EA-12-051 (SFP Ll) Overall Integrated Implementation Plan, Rev 0, February 2013

31. Edwin I Hatch Procedure 31 EO-EOP-1 01-1, Emergency Containment Venting (Unit 1)

32. Edwin Hatch Procedure 31 EO-EOP-1 01-2, Emergency Containment Venting (Unit 2)

33. Edwin Hatch Procedure 31EO-EOP-104-1, Primary Containment Venting for H2 and 02 Control (U1)

34. Edwin Hatch Procedure 31 EO-EOP-1 04-2, Primary Containment Venting for H2 and 02 Control (U2)

35. Edwin Hatch Procedure 31EO-EOP-012-1, U1 PC Flowchart

36. Edwin Hatch Procedure 31 EO-EOP-012-2, U2 PC Flowchart

37. Edwin Hatch Procedure 31EO-PCG-001-1, U1 PC-G Flowchart

38. Edwin Hatch Procedure 31 EO-PCG-001-2, U2 PC-G Flowchart

39. Edwin Hatch Procedure 31EO-SAG-001-1, U1 SAG-01 Flowchart

40. Edwin I. Hatch Procedure 31 EO-SAG-001-2, U2 SAG-01 Flowchart

41. Edwin I. Hatch Procedure 31 EO-SAG-002-1, U1 SAG-02 Flowchart

42. Edwin I. Hatch Procedure 31 EO-SAG-002-2, U2 SAG-02 Flowchart

43. Edwin I. Hatch Procedure 31 EO-TSG-001-0, Technical Support Guidelines

44. Edwin I. Hatch Procedure 31 EO-TSG-002-0, Technical Support Appendix J

45. Southern Nuclear Procedure NMP-EP-403, Figure 1, EMG/EDMG Flowchart

46. Consideration of Additional Requirements for Containment Venting Systems for Boiling Water Reactors with Mark I and Mark II Containments, SECY-12-0157, ML12344A030

47. NUREG/CR-711 0, V1, R1, State-of-the-Art Reactor Consequence Analyses (SOARCA) Project: Peach Bottom Integrated Analysis, ML13150A053 HCVS Phase I OIP Page47 of49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Attachment 6: Changes/Updates to this Overall Integrated Implementation Plan Any significant changes to this plan will be communicated to the NRC staff in the 6 Month Status Reports HCVS Phase I OIP Page 48 of 49 Revision 0 06/23114

Enclosure to NL-14-0844 Hatch Hardened Containment Venting System (HCVS) Phase 1 Overall Integrated Plan Attachment 7: List of Overall Integrated Plan Open Items Open Action Comment Item 1 Determine location of Dedicated HCVS Battery transfer switch 2 Determine location of back-up nitrogen bottles 3 Evaluate location of Portable DG for accessibility under Confirmatory action Severe Accident HCVS use 4 Confirm suppression pool heat capacity Confirmatory action 5 Determine location of HCVS Remote Operating Station (ROS) 6 State which approach or combination of approaches Plant Hatch decides to take to address the control of flammable gases, clearly demarcating the segments of vent system to which an approach applies 7 Evaluate SGTS Valve Leakage utilizing criteria from NEI Confirmatory action HCVS-FAQ-05 8 Identify qualification method used for HCVS instruments 9 Evaluate HCVS monitoring location for accessibility, Confirmatory action habitability, staffing sufficiency, and communication capability with Vent-use decision makers 10 Perform severe accident evaluation for FLEX DG use post 24 Confirmatory action hour actions 11 Determine the control document for HCVS out of service time Confirmatory action criteria HCVS Phase I OIP Page 49 of 49 Revision 0 06/23/14