NL-15-2121, Third Six-Month Status Report of the Implementation of the Commission Order with Regard to Requirements for Reliable Hardened Containment Vents (EA-13-109)

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Third Six-Month Status Report of the Implementation of the Commission Order with Regard to Requirements for Reliable Hardened Containment Vents (EA-13-109)
ML15357A212
Person / Time
Site: Hatch  Southern Nuclear icon.png
Issue date: 12/23/2015
From: Pierce C
Southern Co, Southern Nuclear Operating Co
To:
Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-13-109, NL-15-2121
Download: ML15357A212 (70)
v • d • e


Text

{{#Wiki_filter:Charles R. Pierce Southern Nuclear Regulatory Affairs Drrector Operating Company, Inc. a\ 40 Inverness Center Parkway Post Office Box 1295 Birmingham, AL 35201 Tel 205.992 .7872 SOUTHERN Fax 205.992 .7601 NUCLEAR DEC 2 3 2015 A SOUTHERN COMPANY Docket Nos.: 50-321 NL-15-2121 50-366 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant - Units 1 and 2 Third Six-Month Status Report of the Implementation of the Commission Order with Regard to Requirements for Reliable Hardened Containment Vents (EA-13-1 09)

References:

1. NRC Order Number EA-13-109, Order Modifying Licenses with Regar d to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated June 6, 2013.
2. NEI13 -02, Industry Guidance for Compliance with NRC Order EA-13-109, To Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accide nt Conditions, Revision 0, dated November 2013.
3. NRC Interim Staff Guidance JLD-ISG-2013-02, Compliance with Order EA-13-109, Order Modifying Licenses with Regar d to Reliable Hardened Containmen t Vents Capable of Operation Under Severe Accide nt Conditions, Revision 0, dated November 2013.
4. SNC Letter, Edwin I. Hatch Nuclear Plant - Units 1 and 2 Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licens es with Regard to Requirements for Reliable Hardened Containment Vents ( EA-13
                                                                             -109), dated June 27, 2014.
5. NRC letter, Edwin I. Hatch Nuclear Plant Units, 1 and 2 -Inter im Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 1 of Order EA-13
                                                                           -109 (Severe Accide nt Capable Hardened Vents), dated March 25,20 15 (ML14335A137).
6. NEI13 -02, Industry Guidance for Compliance with NRC Order EA-13-109, To Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accide nt Conditions, Revision 1, dated April 2015.
7. NRC Interim Staff Guidance JLD-ISG-2015-01, Compliance with Order EA-13-109, Order Modifying Licenses with Regar d to Reliable Hardened Containmen t Vents Capable of Operation Under Severe Accide nt Conditions, Revision 1, dated April 2015.
8. NRC Endorsement of "Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Template," Revision 1, dated Septe mber 22,20 15, and Frequently Asked Questions (FAQs) 10, 11, 12, and 13, dated October 8, 2015 La?ies and Gentlemen:

On June 6, 2013, the Nuclear Regulatory Commission (NRC) issued an Order (Reference 1) to Southern Nuclear Operating Company (SNC) . Reference 1 was immediately effective and

U.S. Nuclear Regulatory Commission NL-15-2121 Page2 directs the Edwin I. Hatch Nuclear Plant - Units 1 and 2 (HNP) to install a reliable hardened venting capability for pre-core damage and under severe accident conditions, including those involving a breach of the reactor vessel by molten core debris. Specific requirements are outlined in Attachmen t 2 of Reference 1. In addition, Reference 1 also required submission of a Phase 1 overall integrated plan pursuant to Section IV, Condition D, and status reports at six-month intervals thereafter. SNC submitted the overall integrated plan (OIP) by letter dated June 27, 2014 (Reference 4). This letter is being submitted to satisfy the requirements of providing the third six-month update for Phase 1 of the Order in accordance with Section IV, Condition D.3, of Reference 1, and the OIP for Phase 2 of the Order in accordance with Section IV, Condition D.2 of Reference 1. The third six-month update for Phase 1 of the Order is incorporated into the HCVS Phase 1 and Phase 2 overall integrated plan document which provides a complete updated Phase 1 OIP, a list of the Phase 1 OIP open items, and addresses the NRC Interim Staff Evaluation open items for Phase 1 contained in Reference 5. Future six-month status reports will provide the updates for both Phase 1 and Phase 2 OIP implementation in a single status report. This letter contains no new NRC commitments. If you have any questions, please contact John Giddens at 205.992.7924. Mr. C. A. Pierce states he is the Regulatory Affairs Director for 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, C.f{ ~ C. A. Pierce Regulatory Affairs Director CRP/JMG/GLS 

                                                                            '2015.

My commission expires: /a -!-,;l a I '1

Enclosure:

Hatch Hardened Containme nt Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan, Revision 1

U.S. Nuclear Regulatory Commissio n NL-15-2121 Page 3 cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Bost, Executive Vice President & Chief Nuclear Officer Mr. D. R. Vineyard, Vice President - Hatch Mr. M. D. Meier, Vice President - Regulatory Affairs Mr. B. J. Adams, Vice President - Engineering Mr. D. R. Madison, Vice President - Fleet Operations Mr. G. L. Johnson, Regulatory Affairs Manager- Hatch RType: CHA02.004 U. S. Nuclear Regulatory Commissio n Mr. V. M. McCree, Director of the Office of Nuclear Reactor Regulations Mr. L. D. Wert, Regional Administra tor (Acting) Mr. R. E. Martin, NRR Senior Project Manager- Hatch Mr. D. H. Hardage, Senior Resident Inspector- Hatch Ms. J. A. Kratchman, NRRIJLD/P MB Mr. E. E. Bowman, NRR/DPR/ PGCB State of Georgia Mr. J. H. Turner, Director- Environme ntal Protection Division

Edwin I. Hatch Nuclea r Plant - Units 1 and 2 Third Six-Mo nth Status Report of the Implem entation of the Commi ssion Order with Regard to Requirements for Reliable Hardened Contain ment Vents (EA-13-109) Enclosu re Hatch Hardened Contain ment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan, Revisio n 1

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 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 EA-13-109, Option B.2 Part 3.1 Boundary Conditions for SAWA Part 3.1A Boundary Conditions for SAWAIS AWM Part 3.18 Boundary Conditions for SAWAIS ADV Part 4: Programmatic Controls, Training , Drills and Maintenance Part 5: Implementation Schedule Milestones Attachment 1: HCVS/S AWAISA DV Portable Equipment Attachment 2A: Sequence of Events HCVS Attachment 2.1.A: Sequence of Events Timelin e- SAWA I SAWM Attachment 2.1.8: Sequence of Events Timeline - SADV Attachment 2.1.C: SAWA I SAWM Plant-Specific Datum Attachment 3: Conceptual Sketches Attachment 4: Failure Evaluation Table Attachment 5: References : Changes/Updates to this Overall Integrated Implementation Plan : List of Overall Integrated Plan Open Items OIP Phase 1 and Phase 2 Rev. 1 Page 1 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 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 I 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, 2018, 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, 20 I 7, or June 30, 2019, whichever comes first.")

The NRC provided an acceptable approach for complying with Order EA-13-1 09 through Interim Staff Guidance (JLD-ISG-2013-02 issued in November 2013 and JLD-ISG-2015-01 issued in April2015 ). The ISG endorses the compliance approach presented in NEI 13-02 Revisions 0 and I, 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-13-1 09, the NRC staff will use the methods described in the ISGs to evaluate licensee compliance as presented in submittals required in Order EA-13-1 09. 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 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 and JLD-ISG-2015-01. Six month progress reports will be provided consistent with the requiremenfs of Order EA 13-109. 1 OIP Phase 1 and Phase 2 Rev. 1 Page 2 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan The submittals required are:

  • OIP for Phase I of EA-13-1 09 was required to be submitted by Licensees to the NRC by June 30, 2014. The NRC requires periodic (6 month) updates for the HCVS actions being taken.

The first update for Phase I was due December 2014, with the second due June 2015.

  • OIP for Phase 2 of EA-13-1 09 is required to be submitted by Licensees to the NRC by December 31, 2015. It is expected the December 2015 six month update for Phase 1 will be combined with the Phase 2 OIP submittal by means of a combined Phase I and 2 OIP.
  • Thereafter, the 6 month updates will be for both the Phase I and Phase 2 actions until complete, consistent with the requirements of Order EA-13-109.

Note: At the Licensee's option, the December 2015 six month update for Phase I may be independent of the Phase 2 OIP submittal, but will require separate six month updates for Phase 1 and 2 until each phase is in compliance. The Plant venting actions for the EA-13-1 09, Phase 1, 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)(some plants have a designated Primary Operating Station (POS) that will be treated as the main operating location for this order) 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 and Level 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 hours 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.

The Phase 2 actions can be summarized as follows:

  • Utilization of Severe Accident Water Addition (SAWA) to initially inject water into the Reactor Pressure Vessel (RPV) or Drywell.
  • Utilization of Severe Accident Water Management (SAWM) to control injection and Suppression Pool level to ensure the HCVS (Phase 1) wetwell vent (SAWV) will remain functional for the removal of the decay heat from the core from containment.
  • Ensure that the decay heat can be removed from the containment for seven (7) days using the HCVS or describe the alternate method(s) to remove decay heat from the containment from the time the HCVS is no longer functional until alternate means of decay heat removal are established that make it unlikely the drywell vent will be required for containment pressure control.
  • The SAWA and SAWM actions will be manually activated and controlled from areas that are accessible during severe accident conditions.

OIP Phase 1 and Phase 2 Rev. 1 Page 3 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan

  • Parameters measured should be Drywell pressure, Suppression Pool level, SAWA flowrate and the HCVS parameters listed above.
  • Alternatively SA WA and a Severe Accident Capable Drywell Vent (SADV) strategy may be implemented to meet Phase 2 of Order EA 109.

Part 1: General Integrated Plan Elements and Assum ptions Extent to which the guidance, J LD-ISG-2013-02, JLD-ISG-2015-01 and NEI 13-02 (Revision 1), 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, JLD-ISG-2015-01 Compliance will be attained for E.l. Hatch Units 1&2 (Plant Hatch) with no known deviations to the guidelines in JLD-ISG-2013-02, JLD-ISG-2015-01 and NEI 13-02 for each phase as follows:

  • The Hardened Containment Vent System (HCVS) will be comprised of installed and portable equipmen t and operating guidance:
  • Severe Accident Wetwell Vent (SAWV) - Permanently installed vent from the Suppression Pool to the meteorological stack
  • Severe accident Water Addition (SAW A)- A combination of permanently installed and portable equipment to provide a means to add water to the RPV following a severe accident and monitor system and plant conditions.
  • Severe Accident Water Management (SA WM) strategies and guidance for controllin g the water addition to the RPV for the sustained operating period. (reference attachment 2. l.D)
  • Phase 1 (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 l st Quarter 2017 (Unit 2), lst Quarter 2018 (Unit 1)
  • Phase 2 (alternate strategy): by the startup from the fi rst refuelin g outage that begins after June 30, 2017 or June 30, 2019, whichever comes first. Currently scheduled for 1st Quarter 2019 (Unit 2), 1st Quarter 2018 (Unit 1)

If deviations are identified at a later date, then the deviations will be communicated in a future 6 month update following identification. State Applica ble Extreme External Hazard from NEI 12-Q6, Section 4.0-9.0 List resultant determination of screened in hazards from the EA 049 Complianc e. Ref: NEI 13-02 Section 5.2.3 and 0.1.2 OIP Phase 1 and Phase 2 Rev. 1 Page 4 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions 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 assumpti ons to implement NEI 13-02 HCVS, Phase 1 and 2 Actions.

Provide key assumptions associated with implementation of HCVS Phase I and Phase 2 Actions Ref: NEI 13-02, Revision 1, Section 2 NEI 12-06 Revision 0 Mark 1111 Generic EA-13-1 09 Phase 1 and Phase 2 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 4 049-4. 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 sensitive at a time greater than 1 hour) an ELAP is declared and actions begin as defined in EA-12-049 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 hours with a calculation limiting value of 13.35 hours). The power supply scheme for the HCVS shall be in accordance with EA-13-109 and the applicable guidance. (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 hours 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, notification, SFP level and makeup, security response, opening doors for cooling, and initiating conditions for the event, can be credited as previously evaluated for FLEX. (refer to assumption 109-02 below for clarity on SAWA)(HCVS-FAQ-11) Applicable EA-13-1 09 generic assumptions : I 09-01. 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). This is further referenced in HCVS-FAQ-12. 109-02. Portable equipment can supplement the installed equipment after 24 hours provided the portable equipment credited meets the criteria applicable to the HCVS . An example is use of FLEX portable air supply e~uipment 1 that is credited to recharge air lines for HCVS components after 24 hours. The FLEX portable air supply used must be demonstrate d to meet the "SA Capable" criteria that are defined in NEI 13-02 Section 4.2.4.2 and OIP Phase 1 and Phase 2 Rev. 1 Page 5 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions Appendix D Section D.l.3. This assumption does not apply to Phase 2 SAW A/SAWM because SAW A equipment needs to be connected and placed in service within 8 hours from the time of the loss of RPV injection. (Reference HCVS-FAQ-12) I09-03. 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). I 09-04. Existing containment components design and testing values are governed by existing plant primary 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). 109-05. 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 ). I 09-06. 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-0 I) This assumption does not apply to Phase 2 SAW A/SA WM because SAWA equipment needs to be connected and placed in service within 8 hours from the time of the loss of RPV injection and will require more than minimal operator action. I 09-07. 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-0 I). This assumption does not apply to Phase 2 SAWA/SA WM because SAWA equipment is not dedicated to HCVS but shared to support FLEX functions. This is further addressed in HCVS-FAQ-11. I 09-08. 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. MAAP Version 5 was used to develop EPRI Technical Report 3002003301 to support drywell temperature response to SAWA under severe accident conditions. 109-09. 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 I 09 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. This assumption does not apply to Phase 2 SA WM because SA WM requires changes to the EPG/SAGs per approved issue from the BWROG Emergency Procedures Committee. 109-12. Under the postulated scenarios of order EA-13-109 the Control Room is adequately protected from excessive radiation dose due to its distance and shielding from the reactor (per General Design Criterion (GDC) I 9 in I OCFR50 Appendix A) and no further evaluation of its use as the preferred HCVS control location is required provided that the HCVS routi~g is a sufficient distance away from the MCR or is shielded tp minimize impact to the MCR dose. In addition, adequate protective clothing and respiratory protection is available if required to address contamination issues. (reference HCVS-FAQ-01 and HCVS-FAQ-09) OIP Phase 1 and Phase 2 Rev. 1 Page 6 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions I 09-13 . The suppression poollwetwell of a BWR Mark 1/11 containment is considered to be bounded by assuming a saturated environment for the duration of the event response because of the water/steam interactions. I 09- 14. RPV depressurization is directed by the EPGs in all cases prior to entry into the SAGs (reference NEI 13-02 Rev I section 1.1.3) 109- 15 . The Severe Accident impacts is assumed on one unit only due to the site compliance with NRC Order EA-12-049, However, each BWR MK I and II under the assumptions of NRC Order EA- 13-1 09 ensure the capability to protect containment exists for each unit. (HCVS-FAQ-10) 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 disk will be manually breached within 7.3 hours 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. OIP Phase 1 and Phase 2 Rev. 1 Page 7 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1 : General Integrated Plan Elements and Assumptions N~ Plant E. I. Hatch Map of Protected Area and Surrounding Area Main Control Room IEL. 164' -0) Figure 1-1 Plant Hatch Site Layout OIP Phase 1 and Phase 2 Rev. 1 Page 8 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumpt ions 

                                                                    §    D===t 5

unit 1 Electrical If~i I 11 () ("ooocJohCO...T Figure 1-2 Figure 1-3 Hatch Reactor Building Elevation View Hatch Control Building Ground Floor (EL 130) OIP Phase 1 and Phase 2 Rev. 1 Page 9 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 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 time line attachment. See attached sequence of events time line (Attachment 2) Ref: EA-13-109 Section 1.1.1, 1.1.2, 1.1.3/ 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. Initial 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 Location I Notes Component Hand switches located in the or at the Remote MCR Operating Station (ROS), depending on where operator of HCVS is stationed 

                               =~~~--~-~~---- +~-~~~~~--~~------r-------------------

Panels in MCR containing PCIV interlocks Hand switch located in the Unit 2 only. MCR for condensate drain Unit 1 N/A valve And at ROS panel Manual hand wheels for valves Not required during at the argon bottle and at the SA event. Only piping at the argon bottle station required if I performing early venting for FLEX OIP Phase 1 and Phase 2 Rev. 1 Page 10 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent

5. Close argon cylinder valve & Manual hand wheels for valves Not required during valve I/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
          ----~--~--~---~~==~--------r~~--~~~*-------- --~~~--~~-------
6. Open Wetwell PCIVs Hand switches located in the And at ROS l/2T48-F318 & 1/2T48-F326 MCR
7. Open HCVS vent control Hand switch for valve in the And at ROS valve I/2T48-F082 MCR
8. Align power supplies for all Instruments and controls located Prior to depletion of valves and instruments via in the MCR or Control Building station batteries, Inverters I/2R44-S006 & actions will be l/2R44-S007. required to swap to dedicated HCVS power supply.
          ------~--~---------~*----~---- ~~---------~--~~-----r~-----~~----~
9. Replenish pneumatics with Primary nitrogen bottles for Prior to depletion of replaceable nitrogen bottles FLEX response and early the pneumatic venting are located in the sources actions will Reactor Building. Back-up be required to nitrogen bottles are installed in connect back-up the Control Building to ensure sources at a time severe accident pneumatic greater than 24 supply access. hours.
10. Re-align power supplies for all Instruments and controls located Prior to depletion of valves and instruments via in the MCR or Control Building the installed power Inverters I/2R44-S006 & sources actions will l/2R44-S007 . be required to connect back-up sources at a time greater than 24 hours.

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 failure of RCIC I after a black start where failure occurs because of subjectiyety assuming over injection.
3. Case 3 is based on NUREG-1935 (SOARCA) results for a prolonged SBO (or ELAP) with the loss ofRCIC case without black start.

OIP Phase 1 and Phase 2 Rev. 1 Page 11 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent The followin g is a discussion of time constraints identified in Attachment 2A 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 rel iable 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 hours, HCVS battery capacity will be available to extend past 24 hours. 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 hours is acceptable because the actions can be performed any time after declaration of an ELAP ( 1 hour) until the venting is needed at 7.3 hours 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 2A.

  • At 12 hours, 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 hours, HCVS battery capacity will be available to extend past 24 hours. 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 hours.
  • At 24 Hours, temporary generators will be installed and connected to the pigtail to power up battery chargers to supply power to HCVS critical components/instruments; time sensitive at a time greater than 25 hours (>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 hours. DG will be deployed 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 hours 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. Modifications will be implemented to facilitate the connections and operational actions required to supply power within 10 hours 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 hours for HCVS operation. For Phase 2 applicability, the 8-10 hours will change to 6-7 hours, since it provides power to the SAWA Valves, and will be validated by the Phase 2 Verification and Validation activity, thus providing power by 7 hours,

  • 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 hours assuming a minimum of 8 HCVS cycles. Thus 24 hours 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 hourl OIP Phase 1 and Phase 2 Rev. 1 Page 12 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Discussion of radiological and temQerature constraints identified in Attachment 2A

  • At <7.3 hours, 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- I 2-049 to a value Jess than or equal to PSP.
  • At 12 hours, 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 I -1).

[OPEN ITEM 1: Determine location of dedicated HCVS batter~ transfer switch - Switch is located on ground elevation of Control Building]

  • 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 in the Control Building or yard area.

[OPEN ITEM 2: Determine location of back-uQ nitrogen bottles- Nitrogen Bottles will be located in the Control Building]

  • 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 hours for HCVS operation and at 8 hours for SAWA operation (refer to section 3. I of this OIP). Current battery durations are calculated to last greater than 26 hours. 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 hours 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 .

[OPEN ITEM 3: Evaluate location of QOrtable DG for access ibilit~ under Severe Accident HCVS use- Portable DG will be staged and OQerated adjacent to the Reactor Building substantiall~ awa~ from the HCVS QiQing or the main stack release point]

  • At >24 hours, power supply 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 Si!,.e and Basis (EA-13-109 Section 1.2.1 I NE113-02 Section4.1.1~ 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 Caeaci!J. (EA-13-109 Section 1.2.1 I NEI 13-02 Section 4.1.1l Indicate any exceptions to the 1% decay heat r1moval criteria, including reasons for the exception. Provide lthe heat capacity of the suppression pool in terms of time versus pressurization capacity, assuming suppression pool is the injection source. OIP Phase 1 and Phase 2 Rev. 1 Page 13 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Vent Path and Discharge (EA-13-109 Section1.1.4, 1.2.2 I NE/13-02 Section 4.1.3, 4.1.5 and Appendix FIG) Provides a description of Vent path, release path, and impact of vent path on other vent element items. Power and Pneumatic Supplv Sources (EA-13-109 Section1.2.5 & 1.2.6 I NE/13-02 Section4.2.3, 2.5, 4.2.2, 4.2.6, 6.1) Provide a discussion of electrical power requirements, including a description of dedicated 24 hour 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 hour 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 of Control Panels (EA-13-109 Section1.1.1, 1.1.2, 1.1.3, 1.1.4, 1.2.4, 1.2.5 I NE/13-02 Section4.1.3, 4.2.2, 4.2.3, 4.2.5, 4.2.6, 6.1.1 and Appendix 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. Hvdrogen (EA-13-109 Section 1.2.10, 1.2.11, 1.2.12 I NE/13-02 Section 2.3,2.4, 4.1.1, 4.1.6, 4.1.7, 5.1, & Appendix H) State which approach or combination of approaches the plallt will take to address the control offlammable gases, clearly demarcating the segments of vent system to which an approach applies Unintended Cross Flow of Vented Fluids (EA-13-109 Section 1.2.3, 1.2.12 I NE/13-02 Section 4.1.2, 4.1.4, 4.1.6 and Appendix H) Provide a description to eliminate/minimize unintended cross flow ofventedfluids with emphasis on inteifacing ventilation systems (e.g. SGTS). What design features are being included to limit leakage through inteifacing valves or Appendix J type testing features? Prevention o{/nadvertent Actuation (EA-13-109 Section1.2.71N E/13-02 Section4.2.1) The HCVS shall include means to prevent inadvertent actuation Component Qualifications (EA-13-109 Section2.1 I NE/13-02 Section5.1, 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 ofHCVS (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 Section2.2 I NE/13-02 Section5.2, 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 peiformance that is capable of ensuring HCVS functionality followin g a seismic event. (reference /SG-JLD-2012-01 and /SG-JLD-2012-03 for seismic details.) The components including instrumentption external to a seismic category I (or equivalent building or enclosure should be designed to meet the external haza'rds that screen-in for the plant as defined in guidance NE/12-06 1 as endorsed by JLD-ISG-12-01 for Order EA-12-049. OIP Phase 1 and Phase 2 Rev. 1 Page 14 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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 requiremellfs, 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 pe1jormance 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 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 and frequency ranges). Such testing and analysis should be similar to that pelformedf or the plant licensing basis. Vent Size and Basis The HCVS wetwell path is designed for venting steam/energy at a nominal capacity of I% 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 I% 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 hours. 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 hours following the ELAP event. At about 12 hours, power can be transferred to the HCVS dedicated batteries t~at will supply power for an additional time of> 12 hours. At ~4 hours, 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 OIP Phase 1 and Phase 2 Rev. 1 Page 15 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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 hours, 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 hours, backup nitrogen provided by nitrogen supply bottles will be manually valved-in and replenished as needed. I. 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 (SOY) 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 hours. Beyond the first 24 hours, 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 eight valve operating cycles for the HCVS valve for the first 24 hours.

2. Following the initial 24 hour period, additional motive force will be supplied from nitrogen bottles that will be staged at a gas cylinder rack located (in the control building) such that radiological impacts are not an issue. Additional bottles can be brought in as needed.
3. An a sessment 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 2A.

[OPEN ITEM 5: Determine location of HCVS Remote Operating Station CROS) for both units. Utilize HCVS-FAQ-01 in the response. - ROS will be located at the 147'elevation of the Control Building, one floor below the elevation of the MCRJ

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 the 147' elevation of the Control Building, one floor below the elevation of the MCR . I I [OPEN ITEM 5: Determine location of HCVS Remote Operatin g Station CROS) for both units. Utilize OIP Phase 1 and Phase 2 Rev. 1 Page 16 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent HCVS-FAQ-01 in the response- ROS will be located at the 147'elevation of the Control Building, one floor below the elevation of the MCR.l Hydrogen As is required by EA- I 3- I 09, Section 1.2. I I, 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- Plant Hatch plans to use option I of the endorsed white paper HCVS-WP-03 and power up the mixing chamber fan in the base of the metrological stack.] 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 SOY must be energized to allow the motive air to open the valve. Specifically: I. The PCIS control circuit will be used during all "design basis" operating modes including all design basis transients and accidents.

2. 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 .]

3. 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. Main stack dilution fans will be repowered prior to venting operations for severe accident with core debris ex-vessel.

Prevention of Inadverten t Actuation EOPIERG 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.

  • 1fhe features that prevent inadvertent actuation are two PCIV' ~ in series powered from different divisions, a rupture disk, or key lock switches. Procedures also provide clear guidance to not circumvent containment integrity by simultaneou sly opening Suppression Pool and drywell vent valves during any design basis transient OIP Phase 1 and Phase 2 Rev. 1 Page 17 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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-13-109 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 IOCFR 100. 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 (EQ) 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* HCVS Process Temperature IS09001/ IEEE 344-2004 I Demonstration HCVS Process Radiation Monitor IS09001/ IEEE 344-2004 I Demonstration HCVS Process Valve Position IS09001/ IEEE 344-2004 I Demonstration HCVS Pneumatic Supply Pressure IS09001/ IEEE 344-2004/ Demonstration HCVS Electrical Power Supply Availability IS09001/ IEEE 344-2004 I Demonstration

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

OIP Phase 1 and Phase 2 Rev. 1 Page 18 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent [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/Alternate 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 Joss 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 hours will be provided by two air accumulator tanks and station service batteries, supplemented by installed backup battery power sources. Beyond the first 24 hours, 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 Drywell Pressure and Suppression Pool 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 rugged performance 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 l, SS and 300# ASME or B3l.1, NEMA 4, etc.) for the plant and to ensure functionality following a design basis earthquake. The torus hardened vent (THY) 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 implemeqted 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 upgrad~ the THV to a hardened containment vent system (HCVS), will meet the requirements of Order EA-13-109 and remain OIP Phase 1 and Phase 2 Rev. 1 Page 19 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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. (reference HCVS-FAQ-08) 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 required. (reference HCVS-WP-04) 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-13-1 09 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:

  • 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;
  • ade.quacy 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 IE 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.

OIP Phase 1 and Phase 2 Rev. 1 Page 20 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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-13-109 Section 1.1.4 I NEI 13-02 Section 2.2 First 24 Hour Coping Detail Provide a general description of the venting actions for first 24 hours using installed equipment including station modifications that are proposed. Ref: EA-13-109 Section 1.2.6 I 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 BDBEE hazards identified in part I of this OIP. Initial 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 in response to this Order. Both locations minimize plant operators' exposure to adverse temperature and radiological conditions and are protected from hazards assumed in Part I of this report. Permanently installed power and motive air/gas capability will be available to support operation and monitoring of the HCVS for 24 hours. Permanently installed equipment will supply air and power to HCVS for 24 hours 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 8 open/close cycles under ELAP conditions over the first 24 hours 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 PC IV s 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 val ve is normally key-locked closed and has a rupture disc located downstream. This rupture disc has a burst set pressure above the header pressure (at the disc) 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 than24 hours using portable and installed equipment including station modifications that are prolfsed. J Ref: EA-13-109 Section 1.2.4, 1.2.8 I NEI 13-02 Section 4.2.2 OIP Phase 1 and Phase 2 Rev. 1 Page 21 of 66 Decembe r 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Part 2 Boundary Conditio ns for WW Vent: BDBEE Venting After approximately 24 hours, 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 hours. 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 I 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 hours following the ELAP event (less than 3 planned actuations for FLEX), additional bottles can be connected to support sustained operation. After 24 hours, 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. NEI 13-02 §6.1.2 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-00 1-0, Technical Support Guidelines; 31 EO-EOP-1 01-1/2, Emergency Containment Venting; and, 31 EO-EOP-104-112, 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 nitrogen bottles for pneumatic support of the HCVS air actuators for the first 72 hours following an ELAP event.
  • Provide a means to manually breach the rupture disc in the HCVS header to allow for flow.

EA- 13-109 Modifications

  • Install dedicated batteries and disconnect switches to supply power to HCVS for the second 12 hours 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) modification s listed above (rupture disc instrumentation). I I

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

OIP Phase 1 and Phase 2 Rev. 1 Page 22 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: BDBEE Venting 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: Ke1: Parameter Comuonent Identifier Indication Location HCVS Effluent temperature 112T48-N150 MCRIROS HCVS Pneumatic supply pressure 1P52-N060, 2P52-N030 MCRIROS HCVS valve position indication 1/2T48-F318, 1/2T48-F326, MCRIROS 1/2T48-F081, 112T48-F082, 1T46-F005, 2T46-F002A/B , 2T48-F085 Rupture Disc Pressure 112T48-R030 Reactor Building 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): Ke1: Parameter Comuonent Identifier Indication Location Drywell pressure I/2T48-R608/R609 MCR Torus pressure I/2T48-R608/R609 MCR Torus water temperature 112T47-R611/R612 MCR Torus level 1/2T48-R607 AlB MCR Reactor pressure I /2C32-R605A/B MCR Drywell radiation 112T48-R601A/B MCR HCVS indications for HCVS pneumatic supply pressure and HCVS effluent temperature will be installed in the MCR to comply with EA-13-109. Notes: None I I OIP Phase 1 and Phase 2 Rev. 1 Page 23 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS} Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: BDBEE Venting Part 2: Boundary Conditions for Wet Well Vent 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 NEI 13-02 Section 2.3 First 24 Hour Coping Detail Provide a general description of the venting actions for first 24 hours 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. Initial 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 Part 2 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 a ROS to be installed as part of the response to this Order. Both locations minimize plant operators' exposure to adverse temperature and ra9iological conditions and are protected from hazards assumed in Part 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 mon itoring of the HCVS for 24 hours. System control:

1. Active: PCIVs are operated in accordance with EOPs to control containment pressure. The HCVS is designed for a minimum of 8 open/close cycles of the isolation valve under ELAP conditions over the first 24 hours following an ELAP. HCVS venting will be directed per the SAMGs. Jumpers will be used to override the containment isolation circuit on the PCIVs needed to vent containment.
u. Passive: Inadvertent actuation protection is provided by the current containment isolation circuitry
                !associated with the PCIVs used to operate the HCVS . In ad9ition, 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 (at the disc) expected during a design basis event.

OIP Phase 1 and Phase 2 Rev. 1 Page 24 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: Severe Accident Venting Greater Than 24 Hour Coping Detail Provide a general description of the vellfing actions for greater than 24 hours 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 I of this report. Connections will be pre-engineered quick disconnects or similar arrangement to minimize manpower resources. After 24 hours, 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 hours, available personnel will be able to connect supplemental nitrogen to the HCVS if greater than 8 HCVS cycles have occurred or the pneumatic pressure is low. Sufficient nitrogen bottles will be staged to support operations for up to 72 hours 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 gost 24 hour 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 implementatio n The operation of the HCVS is governed the same for SA conditions as for BDBEE conditions, except there is no 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 other~ will be newly installed (to comply with the vent order) I OIP Phase 1 and Phase 2 Rev. 1 Page 25 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System {HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundarl£ Conditions for Wet Well Vent 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: Ke1: Parameter Com~onent Identifier Indication Location HCVS effluent temperature I/2T48-NI50 MCRIROS HCVS pneumatic supply pressure I P52-N060, 2P52-N030 MCRIROS HCVS valve position indication 1/2T48-F318, I/2T48-F326, MCRIROS I/2T48-F081, I/2T48-F082, I T46-F005, 2T46-F002A/B, 2T48-F085 HCVS power status TBD MCRIROS HCVS effluent radiation monitor I/2T48-N 152 MCRIROS 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-13-109. Notes: None OIP Phase 1 and Phase 2 Rev. 1 Page 26 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: HCVS Support Equipment Functions Determine venting capability support functions needed Ref: EA-13-1 09 Section 1.2.8, 1.2.9/ NEl 13-02 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 hours. 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 hours. 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 l/2T48-F082 vent valve. Severe Accident Venting Provide a general description of the Severe Accident Venting actions support functions. Identify methods and strategy( ies) utili~ed to achieve venting results. Ref: EA-13-109 Section 1.2.8, 1.2.9 I 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 hours, a set of dedicated HCVS batteries will be available to feed HCVS loads via a manual transfer switch. At 24 hours, power will be switched back to the normal configuration powered by FLEX generators evaluated for SA capability. Back-up nitrogen bottles will be installed in the Control Building to be available to tie-in supplemental pneumatic sources before the air accumulator tanks are depleted. Details Provide a brief description of Procedures I Gjidelines: Confirm that procedure/guidance exists or will be developed to support implementation. I OIP Phase 1 and Phase 2 Rev. 1 Page 27 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: HCVS Support Equipment Functions 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 hours. 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. EA- t 2-049 Modifications applicable to HCVS operation

  • Provide connection points and cabling at the control building wall and turbine building (SW Corner) to connect FLEX 600V AC diesel generators to the 600 V AC Bus C and Bus D to provide power to the battery chargers and critical AC components after 24 hours.

EA 109 Modification:

  • Provide piping and connection points at a suitable location in the control building to connect portable nitrogen bottles for motive force to HCVS components after 24 hours. 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- t 2-06 section t I 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 plallf 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-t 2-049 compliance) Pressure gauge on supplemental nitrogen bottles, to be staged with Nitrogen bottles. Notes: None OIP Phase 1 and Phase 2 Rev. 1 Page 28 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar)£ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: HCVS 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 I NEI13-02 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 protected how the equipment will be 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 hours for the valve motive force. OIP Phase 1 and Phase 2 Rev. 1 Page 29 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3: Boundary Conditions for EA-13-1 09, Option 8.2 General: Licensees that use Option B. I of EA-13-109 (SA Capable DW Vent without SAWA) must develop their own OJP. This template does not provide guidance for that option. Licensees using Option 8.2 of EA-13-109 (SAWA and SAWM or 545°F SADW Vent (SADV) with SAWA) may use this template for their OJP submittal. Both SA WM and SADV require the use of SA WA and may not be done independently. The HCVS actions under Part 2 apply to all of the follo wing: This part is divided into the following sections: 3.1: Severe Accident Water Addition (SA WA)

3. l .A: Severe Accident Water Management (SA WM)
3. J.B: Severe Accident DW Vent (545 deg F)

Chart on Attachment 2./.C lists the plant-specific information to support SAWA and SAWM actions. Provide a sequence of events and identify any time constraint required for success including the basis for the time constraint. SAWA and SAWM or SADV Actions supporting SA conditions 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 walkthrough of deployment). Actions already identified under the HCVS part of this template need not be repeated here. The time to establish the water addition capability into the RPV or DW should be less than 8 hours from the onset of tlze los of all injection sources.

  • Electrical generators satisfying the requirements of EA-12-049 may be credited for powering components and instrumentation needed to establish a flow path.
  • Time Sensitive Actions (TSAs) for the purpose of SA WA are those actions needed to transport, connect and start portable equipment needed to provide SA WA flow or provide power to SA WA components in the flow path between the connection point and the RPV or drywell. Actions needed to establish power to SA WA instrumentation should also be included as TSAs.

Ref: NEI 13-02 Section 6.1.1.7.4.1, 1.1.4, 1.1.5 The operation of the HCVS using SAWA will be designed to minimize the reliance on operator actions in response to hazards listed in Part 1. Initial operator actions will be completed by plant personnel and will include the capability for remote-manual initiation from the MCR using control switches, at MCC/Busses in the Control Building and locally at the intake structure. In addition, HCVS operation may occur at the ROS on the 147'elevation in the Control Building. Timelines (see attachments 2 and 2.1.A for SAWA and SAWM) were developed to identify required operator response times and actions. The timelines are an expansion of Attachment 2 and begin either as core damage occurs (SAWA) or after initial SAWA injection is established and as flowrate is adjusted for option B.2 (SA WM). The timelines are appropriate for both in-vessel and ex-vessel core damage conditions. OIP Phase 1 and Phase 2 Rev. 1 Page 30 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundar~ Conditions for SAWA Table 3.1 - SAW A Manual Actions Primary Action Primary Location I Component Notes I. Establish HCVS capability in accordance with Part 2 of this

  • MCRor ROS guidance.
2. Connect SAW A pump I motive component to water source
  • River
3. Connect SAW A pump discharge to injection piping
  • Use installed piping
  • RHRSW at Intake
4. Power up SAW A (RHR/RHRSW)
  • RHR/RHRSW valves may be
  • Should be done as soon as valves with EA-12-049 (FLEX) operated from the main possible generator control room after re-establishing power to the MOVs using the FLEX diesel generator
5. Inject to RPV using SAWA pump (diesel)
  • gpm Initial SAWA injection rate is 500
6. Monitor SAWA indications
  • UsingPump 0

Skid mounted Flow 0 Valve Position

7. Use SA WM to maintain availability of the SAWV (Section
  • MCR and Intake
  • Monitor DW Pressure and Suppression Pool Level in MCR
3. 1.A)
  • Control SAWA at pump skid at intake (reduced to IOOGPM or less)

Discussion of timeline SAWA identified item HCVS operations are discussed under Phase I of EA 109 (Section 2 of this OIP).

  • 7.5 Hours - Establish electrical power and other EA-12-049 actions needed to support the strategies for EA 109, Phase 1 and Phase 2. Action being taken within the reactor building under EA-12-049 conditions after RPV level lowers to 2/3 core height must be evaluated for radiological conditions assuming permanent containment shielding remains intact. (HCVS-FAQ-12) All other actions required are assumed to be in-line with the FLEX timeline submitted in accordance with the EA-12-049 requirements.
  • Less than 8 Hours- Initiate SAWA flow to the RPV. Having the HCVS in service will assist in minimizing the peak DW pressure during the initial cooling conditions provided by SAWA.

I Severe Accident Operation I OIP Phase 1 and Phase 2 Rev. 1 Page 31 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundary Conditions for SAWA Determine operating requirements for SA WA , such as may be used in an ELAP scenario to mitigate core damage. Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3/ NEI13-02 Section 1.1.6, 1.1.4.4 It is anticipated that SAW A will be used in Severe Accident Events based on presumed failure of injection systems or presumed failure of injection systems in a timely manner. This does not preclude the use of the SAWA system to supplement or replace the EA-12-049 injection systems if desired. SAWA will consist of both portable and installed equipment. The motive force equipment needed to support the SAWA strategy shall be available prior to t=8 hours from the loss of injection (assumed at T=O). The SAW A flow path includes methods to minimize exposure of personnel to radioactive liquids I gases and potentially flammable conditions by inclusion of backflow prevention. The check valve is integral with the pump skid and will close and prevent leakage when the SAW A pump is secured. RHR LPCI injection mode has installed ECCS backflow prevention devices ( 112E II-F050NB) qualified for accident scenarios. Description of SAW A actions for first 24 hours: T<l hr:

  • No evaluation required for actions inside the reactor building for SAWA. Expected actions are:

o None T=l -7* hr:

  • Evaluation of core gap release impact to reactor building access for SAWA actions is required. It is assumed that reactor building access is limited due to the source term at this time unless otherwise noted.

Expected actions are: o None

  • Establish electrical power for SAWA systems and indications using EA-12-049.

o step 4 of table 3.1 above

  • The assumed times ofT= I hour to T=8 hours to establish the bounds of applicability of radiological evaluations have been reduced to T=l h to T=7 hours in order to provide sufficient margin to inform operator action feasibility evaluations and will be further informed by emergency response dose assessment activities during an actual event.

T<8hr:

  • Establish flow to the RPV using SAWA systems. Begin injection at a maximum rate, not to exceed 500 gpm.

o steps 2, 3, 5 and 6 of table 3.1 above T<8 -12 hr:

  • Continue injection for 4 hours after SAWA injection begins at initial SAWA rate.

T<l2 hrs:

  • Jroceed to SAWM actions (Part 3.l.A) o step 7 of table 3.1 above OIP Phase 1 and Phase 2 Rev. 1 Page 32 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundary Conditions for SAWA Greater Than 24 Hour Coping Detail Provide a general description of the SAWA actions for greater than 24 hours using portable and installed equipment including station modifications that are proposed. Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3/ NEI 13-02 Section 4.2.2.4.1 .3.1, 1.1.4, SAW A Operation is the same for the full period of sustained operation. SAWM flowrates will be directed to preserve the availability of the HCVS wetwell vent (see 3.1.A). Details: Details of Design Characteristic s/Performance Specifications SA WA shall be capable of providing a RPV or DW injection rate of 500 gpm within 8 hours of a loss of all RPV injection following an ELAP/Severe Accident. SA WA shall meet the design characteristics of the HCVS with the exception of the dedicated 24 hour power source. Hydrogen mitigation is not applicable to SA WA. Ref: EA-13-109 Attachment 2, Section B.2.1, B.2.2, B.2.3/ NEI 13-02 Section 1.1.4 Equipment Locations/Con trols/Instrume ntation The locations of the SAWA equipment and controls, as well as ingress and egress paths have been evaluated for the expected severe accident conditions (temperature, humidity, radiation) for the Sustained Operating period. Equipment has been evaluated to remain operational throughout the Sustained Operating period. Personnel exposure and temperature I humidity conditions for operation of SAWA equipment will not exceed the limits for ERO dose and plant safety guidelines for temperature and humidity. The flow path will be from the FLEX suction in the Altamaha river through the FLEX pumps with 4 outlets with individual flow indicators. One indicator will be dedicated to the unit in a Severe Accident, and the flow will be monitored that is pro ided to the RHR service water FLEX header. The monitored water flow rate will pass through the RHRSW piping to the Reactor Building where it will connect with the RHR system by opening MOV s from the MCR that interconnect the systems. The flow will then be directed into the RPV via the LPCI injection valves. Cross flow into other portions of the RHR system will be isolated by ensuring closure of the MOV s from the MCR. DW pressure and Suppression Pool level will be monitored and flow rate will be adjusted by use of the FLEX pump control valve at the Intake Structure. Communication will be established between the MCR and the FLEX pump location. MOV s will be powered from the FLEX diesel generators connected as described in the EA-12-049 compliance documents. The MOVs will be operated in series (not parallel) to limit the potential for overloading the FLEX DGs. The FLEX DGs are located near the Control Building which is significantly away from the discharge of the HCVS at the Main Meteorological Stack. Refueling of the FLEX DG will be accomplished from the EDG fuel oil tanks as described in the EA-12-049 compliance documents. The Intake Structure is a significant distance from the discharge of the HCVS at the Main Meteorological Stack. (see mechanical and electrical sketches in attachments, plant layout sketches in the ass~mptions part and a list of actions elsewhere in this part) I Evaluations for projected SA conditions (radiation I tem_IJ_erature) indicate that _personnel can complete the initial and OIP Phase 1 and Phase 2 Rev. 1 Page 33 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundar~ Conditions for SAWA support activities without exceeding the ERO-allowable dose for equipment operation or site safety standards. (reference HCVS-WP-02 ) Electrical equipment and instrumentation will be powered from the existing station batteries, and from AC distribution systems that are powered from the EA-12-049 generator(s). The battery chargers are also powered from the EA-12-049} generator(s) to maintain the battery capacities during the Sustained Operating period. Parameter Instrument Location Power Source I Notes DW Pressure 112T48-R608/R609 MCR Station batteries via EA-12-049 generator Torus Level l/2T48-R607A/B MCR Station batteries via EA-12-049 generator SAWAFiow FLEX Pump Flow FLEX Pump Skid SAWA pump (skid indicator mounted device) SAWA pump power On-Board Generator I/2T48-R607 AlB EA-12-049 generator RHR and RHRSW Valve MCRPanels MCR and Control 1R24-S012/S018B controls Building (2R24-SO II/SO 18A) EA-12-049 generator The instrumentation and equipment being used for SAWA and supporting equipment has been evaluated to perform for the Sustained Operating period under the expected radiological and temperature conditions. Equipment Protection Any SAWA component and connections external to protected buildings have been protected against the screened-in hazards of EA-12-049 for the station via a below grade valve pit connecting to piping in the intake structure and the Reactor Building. Portable equipment used for SAWA implementation will meet the protection requirements for storage in accordance with the criteria in NEI 12-06 Revision 0. Provide a brief description of Procedures I Guidelines: Confirm that procedure/guidance exists or will be developed to support implementation. Ref: EA-13-109 Attachment 2, Section A.3.1, B.2.3/ NEI 13-02 Section 1.3, 6.1.2

  • Hook up FLEX pump to intake manifold per FSG
  • Hook-up and start FLEX DG to repower 1R24-S012(2R24-S011) and 1R24-SOI8B(2R24-S018A)
  • Open 1E11-F073B(2E11-F073A) and 1E11-F075B(2E11 -F075A) using MCR Switches to cross tie RHR with RHRSW
  • Verify using MCR switches that 1/2E11-F003A! F016A, F028A, F048A and 1/2E11-F068AIB are closed to I isolate RHR SDC modes OIP Phase 1 and Phase 2 Rev. 1 Page 34 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundar~ Conditions for SAWA

  • Open I EII-F015B(2EII-F OI5A) and I EII-FOI7B(2EIJ-F 017A) using MCR Switches for RHR LPCJ injection pathway
  • Start FLEX pump via on-board generator
  • Adjust flow rate using skid mounted flow indicator and isolation valve Identify modifications:

List modifications and describe how they support the SA WA Actions. Ref: EA-13-109 Attachment 2, Section B.2.2, I NEI 13-02 Section 4.2.4.4, 7.2.1.8, Appendix I None Component Qualifications: State the qualification used for equipment supporting SA WA Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3/ NEI 13-02 Section I.1.6 Permanently installed plant equipment shall meet the same qualifications as described in Part 2 of this OIP. Temporary/Portable equipment shall be qualified and stored to the same requirements as FLEX equipment as specified in NEI 12-06. SAW A components are not required to meet NEI 13-02, Table 2-1 design conditions. Notes: None OIP Phase 1 and Phase 2 Rev. 1 Page 35 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.A: Boundary Conditions for SAWA/SAWM Time periods for the maintaining SAWM actions such that the WW vent SA WM Actions supporting SA conditions 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 walkthrough of deployment). Actions already identified under the HCVS part of this template need not be repeated here. There are three time periods for the maintaining SA WM actions such that the WW vent remains available to remo ve decay heat from the containment:

  • SA WM can be maintained for> 7 days without the need for a cbywell vent to maintain pressure below PCPL or containment design pressure, whichever is lower.

o Under this approach, no detail concerning plant modifications or procedures is necessmy with respect to how alternate containment heat removal will be provided.

  • SA WM can be maintained for at least 72 hours, but less than 7 days before containment pressure reaches PCPL or design pressure, whichever is lower.

o Under this approach, afunctional description is required of how alternate containment heat removal might be established before containment pressure reaches PCPL or design pressure whichever is lower. Under this approach, physical plant modifications and detailed procedures are not necessary, but written descriptions of possible approaches for achieving alternate containment heat removal and pressure control will be provided.

  • SA WM can be mabztainedfor <72 hours SAWM strategy can be implemented but for less than 72 hours before containment pressure reaches PCPL or design pressure whichever is lower.

o Under this approach, afunctional description is required of how alternate containment heat removal might be established before containment pressure reaches PCPL or design pressure whichever is lower. Under this approach, physical plant modifications and detailed procedures are required to be implemented to insure achieving alternate containment heat removal and pressure control will be provided for the sustained operating period. Ref: NEI 13-02 Appendix C.7 SA WM can be maintained for> 7 days without the need for a drywell vent to maintain pressure below PCPL. Basis for SA WM time frame SA WM can be maintained > 7 days: Plant Hatch is bounded by the evaluations performed in BWROG TP-15-0 11 and representative of the reference plant in NEI 13-02 figures C-2 through C-6. Instrumentation relied upon for SAWM operations is DW pressure and Suppression Pool level. Both of which are initially powered by station batteries and then by the FLEX (EA-12-049) generator which is placed in-service prior to core breach. The DG will provide power throughout the Sustained Operation period (7 days) . (C.7.1.4.2) DW Temperature monitoring is not a requirement for compliance with Phase 2 of the order, but some knowledge of temperature characteristics provides information for the operation staff to evaluate plant conditions under a severe accident and provide confirmation to adjust SAWA flow rates (C.8.3.1) Suppression Pool level indication is !maintained throughout the Sustained Operation period, so th~ HCVS remains in-service. The time to reach the level at which the WW vent must be secured is>?days using SAWM flowrates (C.6.3, C.7.1.4.3) OIP Phase 1 and Phase 2 Rev. 1 Page 36 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.A: Boundar~ Conditions for SAWA/SAWM Procedures will be developed that control the Suppression Pool level in the indicating range, while ensuring the DW pressure indicate the core is being cooled, whether in-vessel or ex-vessel. Procedures will dictate conditions during which SAWM flowrate should be adjusted (up or down) using Suppression Pool level and DW pressure as controlling parameters to remove the decay heat from the containment. (this is similar to the guidance currently provided in the BWROG SAMGs) (C.7.1.4.3) Attachment 2.1.A shows the timeline of events for SAWA I SA WM. (C.7.1.4.4) T able 3.l.B - SAWM Manual Actions Primary Action Primary Location I Notes Component I. Lower SAWA injection rate to control Intake Structure

  • Control to maintain containment and Suppression Pool parameters to ensure Suppression Pool level SAWV remains operational.

and decay heat removal

  • 100 gpm minimum capability is maintained for greater than 7 days
2. Control to SAWM flowrate for containment Intake Structure and MCR
  • SA WM Flowrates will be monitored using the following instrumentation control I decay heat 0 FLEX Pump Flow removal 0 Suppression Pool level DW pressure 0

SAWM flowrates will be controlled using the manual flow control valve at the FLEX pump

3. Establish alternate source of decay heat removal Yard
                                                                    *  >7days
4. Secure SAWA I SAWM Intake Structure
  • When reliable alternate containment decay heat removal is established.

SAWM Time Sensitive Actions Time Sensitive SAWM Actions: 12 Hours- Initiate actions to maintain the Wetwell vent (SAWV) capability by lowering injection rate, while maintaining the cooling of the core debris (SA WM). Monitor SAWM critical parameters while ensuring the SAWV remains available. SAWM Severe Accident Operation OIP Phase 1 and Phase 2 Rev. 1 Page 37 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.A: Boundar~ Conditions for SAWA/SAWM Determine operating requirements for SAWM, such as may be used in an ELAP scenario to mitigate core damage. Ref: EA-13-109 Attachment 2, Section 8.2.2, 8.2.31 NEI 13-02 Appendix C It is anticipated that SA WM will only be used in Severe Accident Events based on presumed failure of plant injection systems as directed by the plant SAMGs. Refer to Attachment 2.1.0 for SAWM SAMG language additions. First 24 Hour Coping Detail Provide a general description of the SA WM actions forfirst 24 hours using installed equipment including station modifications that are proposed. Given the initial conditions for EA-13-109: BDBEE occurs with ELAP Failure of all injection systems, including steam-powered injection systems Ref: EA-13-109 Section 1.2.6, Attachment 2, Section 8.2.2, 8.2.3 I NEI 13-02 2.5, 4.2.2, Appendix C, Section C.7 SAWA will be established as described above. SAWM will use the installed instrumentation to monitor and adjust the flow from SAWA to control the pump discharge to deliver flowrates applicable to the SAWM strategy. Once the SAWA initial flow rate has been established for 4 hours, the flow will be reduced while monitoring DW pressure and Suppression Pool level. SA WM flowrate will be lowered to maintain containment parameters and preserve the WW vent path. SAWA will be capable of injection for the period of Sustained Operation. Greater Than 24 Hour Coping Detail Provide a general description of the SAWM actions for greater than 24 hours using portable and installed equipment including station modifications that are proposed. Ref: EA-13-109 Section 1.2.4, 1.2.8, Attachment 2, Section 8.2.2, 8.2.31 NEI 13-02 Section 4.2.2, Appendix C, Section C.7 SAWM can be maintained> 7 da;rs: The SAWM flow strategy will be the same as the first 24 hours until 'alternate reliable containment heat removal and pressure control' is reestablished. SA WM flow strategy uses the SAWA flow path. No additional modifications are being made for SA WM. Details: Details of Design Characteristic s/Performance Specifications Ref: EA-13-109 Attachment 2, Section 8.2.2, 8.2.3 I NEI 13-02 Section Appendix C I I OIP Phase 1 and Phase 2 Rev. 1 Page 38 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.A: Boundary Conditions for SAWNSAWM SA WM shall be capable of monitoring the containment parameters (DW pressure and Suppression Pool Level) to provide guidance on when injection rates shall be reduced, until alternate containment decay heat/pressure control is established. SAW A will be capable of injection for the period of Sustained Operation. Equipment Locations/Controls/Instrumentation Describe location for SAWM monitoring and control. Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3 I NEI 13-02 Appendix C, Section C.8, Appendix I The SAWM control location is the same as the SAW A control location. Local indication of SAWM flowrate is provided at the pump skid by installed flow instrument qualified to operate under the expected environmental conditions. Injection flowrate is controlled by FLEX manual valve located on the FLEX pump at the Intake Structure Suppression Pool level and DW pressure are read in the control room using indicators powered by the FLEX DG installed under EA- 12-049. These indications are used to control SAWM flowrate to the RPV. Key Parameters: List instrumentation credited for the SA WM Actions. Parameters used for SA WM are:

  • Drywell Pressure*
  • Suppression Pool Level*
  • SAWM Flowrate The Containment Pressure and Suppression Pool Level instruments are qualified to RG 1.97 and are the same as listed in Part 2 of this OIP. The SAWM flow instrumentation is qualified for the expected environmental conditions when needed which is extreme temperatures Notes:

None OIP Phase 1 and Phase 2 Rev. 1 Page 39 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.8: Boundary Conditions for SAWA/SADV Applicabil ity of WW Design C onside r a tions All of Part 2 of this OIP applies to the SADV, with the exception that the temperature qualification for SADV components, and interfacing WW Vent components, shall be rated for 545 Deg F. Table 3.1.C- SADV Man ual Actions N/A Timeline for SADV Describe timeline for SADV actions from the time the WW vent is no longer operational N/A 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 Attachmen t 2, Section B.2.1, B.2.2, B.2.3 I NEI 13-02 Appendix J, HCVS-FAQ -01, HCVS-FAQ - 02, HCVS-FAQ -03, HCVS-FAQ -04 N/A First 24 Hour Coping Detail Provide a general description of the SADV actionsforf irst 24 hours using installed equipment including station modifications that are proposed. Ref: EA-13-109 Attachmen t 2, Section B.1.1, B.1.2 I NEI 13-02 Section 4.2, Appendix I N/A Greater Than 24 Hour Coping Detail Provide a general description of the SADV actions for greater than 24 hours using portable and installed equipment including station modifications that are proposed. Ref: EA-i3-109 Attachmen t 2, Section B.1.1, B.1.2 I NEI 13-02 Secdon 2.5, 4.2.2, Appendix I OIP Phase 1 and Phase 2 Rev. 1 Page 40 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.8: Boundar~ Conditions for SAWA/SADV N/A Details: Provide a brief description of Procedures I Guidelines: Confirm that procedure/guidance exists or will be develop ed to support implementation. Ref: EA-13-109 Attachment 2, Section 8.1.1, 8.1.2/ NEI 13-02 Section 6.1.2 N/A Identify modifications: List modifications and describe how they support the SADV Actions. N/A Key Venting Parameters: List instrumentation credited for the SADV Actions. N/A OIP Phase 1 and Phase 2 Rev. 1 Page 41 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 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 1.2.10, 3.1, 3.2/ NEI 13-02 Sections 5, 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 analyzed for radiation and temperature to ensure they are accessible 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 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/SA WA functionality are applicable in Modes I, 2 and 3.

  • If for up to 90 consecutive days, the primary or alternate means of HCVS/SA W A operation are non-functional, no compensatory actions are necessary.
  • If for up to 30 days, the primary and alternate means of HCVS/SA W A operation are nonfunctional, no compensatory actions are necessary.
  • If the out of service times exceed 30 or 90 days as described above, the following actions will be performed through the sites corrective action program:

o The cause(s) of the non-functionali tjy I o The actions to be taken and the schedule for restoring the system to functional status and prevent recurrence OIP Phase 1 and Phase 2 Rev. 1 Page 42 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 4: Programmatic Controls 1 Training! Drills and Maintenance 0 Initiate action to implement appropriate compensatory actions, and 0 Restore full HCVS functionality at the earliest opportunity not to exceed one full operating cycle.: [OPEN ITEM 11: Determine the control document for HCVS out of service time criteria] Describe training plan List training plans for ajj"ected organizations or describe the plan for training development Ref: EA-13-109 Section 3.2/ NEI 13-02 Section 6.1.3 Personnel expected to perform direct execution of the HCVS/SA W A/SA WM actions 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/ SAWA/SA WM actions, systems or strategies. Training content and frequency will be established using the Systematic Approach to Training (SAT) process. Identify how the drills and exercise parameters will be met. Alignment with NEI I 3-06 and 14-01 as codified in NITF Recommendation 8 and 9 rulemaking The Licensee should demonstrate use of the HCVS/SAWAISAWM system in drills, tabletops, or exercises as follows:

  • Hardened containment vellf 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//oss 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 ELAPI/oss of UHS with core damage. System use is for containment heat removal AND containment pressure control with potentia/for combustible gases (Demonstration may be in conjunction with SAG change).
  • Operation for sustained period with SAWA and SAWM to provide decay heat removal and containment pressure control.

Ref: EA-13-109 Section 3.1/ NEI 13-02 Section 6.1.3 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: Describe the elements of the maintenance plan

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

0 Periodic testing andfrequenc.) should be determined based on equipment type, expected usd and manufacturer's recommendations (further details are provided in Part 6 of this document). OIP Phase 1 and Phase 2 Rev. 1 Page 43 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 4: Programmatic Controls ! Training , Drills and Maintenance 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 documellted 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/SA WA permanent installed equipment should be maintained in a manner that is consistent with assuring that it petforms its fun ction when required.

o HCVS/SA WA permanently installed equipment should be subject to maimenance and testing guidance provided to verify proper function.

  • HCVS/SA WA 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/ 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/SAW A/SAWM 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 and SAW A to ensure reliable operation of the system. Table 4-1: Testing and Inspection Requirements Description Frequency Cycle the HCVS and installed SAWA valves 1 and the Once per everi operating cycle interfacing system boundary valves not used to maintain containment integrity during Mode 1, 2 and 3. For HCVS valves, this test may be performed concurrently with the control logic test described below. Cycle the HCVS and installed SAWA check valves not Once per every other4 operating cycle used to maintain containment integrity during unit operations3 Perform visual inspections and a walk down of HCVS Once per every other4 operating cycle and installed SAWA components Functionally test the HCVS radiation monitors. Once per operating cycle OIP Phase 1 and Phase 2 Rev. 1 Page 44 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 4: Programmatic Controls. Training, Drills and Maintenance Leak test the HCVS. I. 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 conducting Once per every other operating cycle an open/close test of the HCVS control function from its control location and ensuring that all HCVS vent path and interfacing system boundary valves 5 move to their proper (intended) positions.

1 Not required for HCVS and SAWA check valves. 2 After two consecutive successful performances, the test frequency may be reduced to a maximum of once per every other operating cycle. 3 Not required if integrity of check function (open and closed) is demonstrated by other plant testing requirements. 4 After two consecutive successful performances, the test frequency may be reduced by one operating cycle to a maximum of once per every fourth operating cycle. 5 Interfacing system boundary valves that are normally closed and fail closed under ELAP conditions (loss of power and/or air) do not require control function testing under this section. Performing existing plant design basis function testing or system operation that reposition the valve(s) to the HCVS required position will meet this requirement without the need for additional testing. Notes: OIP Phase 1 and Phase 2 Rev. 1 Page 45 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 5: Milestone Schedule Provide a milestone schedule This schedule should include:

  • Modificatio ns timeline
  • Procedure guidance developme nt 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 subject to change. Updates will be provided in the periodic (six month) status reports.

Ref: EA-13-109 Section 0.1, 0.3/ NEI13-02 Section 7.2.1 The following milestone schedules are 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. Phase 1 Milestone Schedule: Phase 1 Milestone Schedule: Milestone Target Activity Comments Completion Status {.Include date changes in Date this columnl Hold preliminary/conceptual design meeting Jun, 2014 Complete Submit Overall Integrated Implementation Plan Jun 2014 Complete Submit 6 Month Status Report Dec.2014 Complete Submit 6 Month Status Report Jun. 2015 Complete Submit 6 Month Status Report Dec. 2015 Complete Simultaneous with Phase 2 OIP U2 Design Engineering On-site/Complete May 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 

             .L U2 Implementation Outage                                        Feb,2017 Procedure Changes Active                                        Mar, 2017 OIP Phase 1 and Phase 2 Rev. 1                 Page 46 of66                           December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 5: Milestone Schedule U2 Walk Through Demonstration/Functional Test Mar, 2017 U 1 Design Engineering On-site/Complete Mar, 2017 Submit 6 Month Status Report Jun.2017 Submit 6 Month Status Report Dec. 2017 U 1 Implementation Outage Feb,2018 U1 Walk Through Demonstration/Functional Test Mar, 2018 Submit Completion Report May, 2018 Phase 2 Milestone Schedule: Phase 2 Milestone Schedule Milestone Target Activity Comments Completion Status {.Include date changes in Date this columnl Submit Overall Integrated Implementation Plan Dec 2015 Complete Hold preliminary/conceptual design meeting Apr2016 Expect to be engineering justification not modifications Submit 6 Month Status Report June 2016 Submit 6 Month Status Report Dec 2016 U1 Design Engineering On-site/Complete Feb 2017 Expect to be engineering justification not modifications Submit 6 Month Status Report June 2017 Operations Procedure Changes Developed Sep 2017 SAMG Revision Site Specific Maintenance Procedure Developed Dec 2017 Expect to be N/ A Training Complete Dec 2017 Submit 6 Month Status Report Dec 201 7 U2 Design Engineering On-site/Complete Feb 2018 Expect to be engineering justification not modifications U1 Implementation Outage Mar2018 Procedure Changes Active Mar 2018 U1 IWalk Through Demonstration/Functional Test Mar 2018 Submit 6 Month Status Report June 2018 OIP Phase 1 and Phase 2 Rev. 1 Page 47 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 5: Milestone Schedule Submit 6 Month Status Report Dec 2018 U2 Implementation Outage Mar 2019 U2 Walk Through Demonstration/Functional Test Mar 2019 Submit Completion Report May 2019 Notes: OIP Phase 1 and Phase 2 Rev. 1 Page 48 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 1: HCVS/SAWAISADV Portable Egui~ment BDBEE Severe Performance Maintenance I PM requirements List portable equipment Venting Accident Criteria 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 (and associated equipment) X X TBD Per Response to EA-12-049 SAWA Pump (and associated equipment) X X TBD Per Response to EA-13-1 09 

                                       -~-
                                             - - - - '--~-~--
                                                                                             /

OIP Phase 1 and Phase 2 Rev. 1 Page 49 of66 December 6, 2015

Enclosure to NL-15-212 1 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2A: Sequence of Events Timeline- HCVS t ... 5 m t= 1 hr t=0s RCIC E LAP SSO stans Ded.ved Case 1 FLEX Successf: t.,7 hrs t.,1Dhrs t., 18hrs Containment Venting ~----------iRef: HNP FLEX 0 Blow Antic:ipa1ory Ponable {~31Dry ven11ng ruptUJ"e diSC Venting generaliOr in nat represented in No Injection place for Fl.EX No Injection SECY-12-01 57) and HCVS loads I 

                                                                                                        *I I

I Level at TAF

  • Case 2
  • J RC IC LateFailu re tQO 23 hrs t"" 24 hrs t ... 34 h rs Ref: S ECY-12-0157 Containment Venting t,..11hrs I

I (based on preventing Begin monitori~ at MCR or ROP I I t ... 24 hrs exceeding PCPL) HCVS pneumatic and batte ry stah.ls. I Repfenish ment of HCVS No replenishmen1 expected to be power and pneumatic required before t = 24 hours I I I supplies I I t ... 12hrs I I Trar!Sfer to I I HCVS Battery I Case 3 RC IC Ea:rly Failu re t""' h r t!>r81Vs tR>11h.rs Ref: SOARCA t ... 24 hrs t"' 12 hrs l_iAWA Injection BeQins I Legend Refe rences: 

    -         ~ OCIII'e cooling maintained                                                             C3Se 1: HN P FLEX 0\llerall l n:egrated Pfan lnjeotJon Lost                                                                           C3Se 2: S ECY 0157 - ML12344A030
    -         lnaeased shinct and leakage of radionuclides pril'n3dy &an \Y                            C3Se 3 : SOARCA - M L 131 50A053
    -         HCVS Post Core Dalnag@ Dose Evaluation Required HCVS Ti~ evaluation .-.auired
                                                                                                                                                            ~-Not to5care )

OlP Phase 1 and Phase 2 Rev. 1 Page 50 of 66 Decem ber 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2.1.A: Sequence of Events Timeli ne- SAWA I SAWM Sustained Operation period T=168 hr ( T= 8 hr 1 T=72 hr --, SAWA Injection Flow beginsT<soo gpm) Control SAWM flow rate using drywell pressure and suppression pool level indications OIP Phase 1 and Phase 2 Rev. 1 Page 51 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2.1.8: Sequence of Events Timeline - SADV N/A OIP Phase 1 and Phase 2 Rev. 1 Page 52 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2.1.C: SAWA I SAWM Plant-Specific Datum SAWV El. 117.1 {331" ) Spillover height 18 inches (EL. 116 Additional freeboard height= 31" 't:~- ------~~E~L- .~ 11:-::6:-:-{3~1= 8"' ) Drywell floor El. 114.5 (300"from Bottom of Torus) level instrument span = 150" to 154" (>12.5' ) Normal Torus (n::vo::: 11

  • l y y
  • El. 101.7 to 102 (146" to
  • Torus water volume at elevations
                                                                                                                             =

o Elevation 150" 679,319 gallons o Elevation 300" = 1,484,580 gallons Bottom of Toru s El. 89.5 {0" ) ---------==~---~

  • Estimated of the rate of level change in the suppression pool for SAWA flow rates*

o 500 gpm = 6 inches per hour average o 100 gpm = 1 inch per hour average 

                                                                                            *Does not consider mass loss rate of steam leaving containment through wetwell vent path OIP Phase 1 and Phase 2 Rev. 1                               Page 53 of66                                         December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2.1.0: SAWM SAMG Approved Language The following general cautions, priorities and methods will be evaluated for plant specific applicability and incorporated as appropriate into the plant specific SAMGs using administrative procedures for EPGISAG change control process and implementation. SAMGs are symptom based guidelines and therefore address a wide variety of possible plant conditions and capabilities while these changes are intended to accommodate those specific conditions assumed in Order EA-13-109. The changes will be made in a way that maintains the use of SAMGs in a symptom based mode while at the same time addressing those conditions that may exist under extended loss of AC power (El.AP) conditions with significant core damage including ex-vessel core debris. Actual Approved Language that will be incorporate d into site SAMG* Cautions:

  • Addressing the possible plant response associated with adding water to hot core debris and the resulting pressurization of the primary containment by rapid steam generation.
  • Addressing the plant impact that raising suppression pool water level above the elevation of the suppression chamber vent opening elevation will flood the suppression chamber vent path.

Priorities: With significant core damage and RPV breach, SAMGs prioritize the preservation of primary containment integrity while limiting radioactivity releases as follows : 

      .!.__ Core debris in the primary containment is stabilized by water addition (SAWA)
  • Primary containment pressure is controlled below the Primary Containment Pressure Limit (Wetwell venting)
  • Water addition is managed to preserve the Mark IIII suppression chamber vent paths, thereby retaining the benefits of suppression pool scrubbing and minimizing the likelihood of radioactivity and hydrogen release into the secondary containment (SAWM)

Methods: Identify systems and capabilities to add water to the RPV or drywell, with the following generic guidance:

  • Use controlled injection if possible.
  • Inject into the RPV if possible.

Maintain injection from external sources of water as low as possible to preserve suppression chamber vent capability.

  • Actual language may vary by acceptable site procedure standards, but intent and structure should follow this guidance.

OIP Phase 1 and Phase 2 Rev. 1 Page 54 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 3: Conceptual Sketches (Conceptual sketches, as necessary to indicate equipment which is installed or equipment hookups necessary for the HCVS Actions) Sketch 1: Electrical Layout of System (preliminary)

  • Instrumentation Process Flow
  • Electrical Connections Sketch 2: P&ID Layout of WW Vent (preliminary)
  • Piping routing for vent path - WW Vent
  • Demarcate the valves (in the vent piping) between the currently existing and new ones
  • WW Vent Instrumentation Process Flow Diagram
  • Egress and Ingress Pathways to ROS, Battery Transfer Switch, DG Connections and Deployment location
  • Site layout sketch to show location/routing of WW vent piping and associated components. This should include relative locations both horizontally and vertically Sketch 3: P &ID Layout of SAWA (preliminary)
  • Piping routing for SAWA path
  • SAWA instrumentation process paths
  • SAWA connections
  • Include a piping and instrumentation diagram of the vent system. Demarcate the valves (in the vent piping) between the currently existing and new ones.
  • Ingress and egress paths to and from control locations and manual action locations
  • Site layout sketch to show locations of piping and associated components. This should include relative locations both horizontally and vertically OIP Phase 1 and Phase 2 Rev. 1 Page 55 of66 Decem ber 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan ES: Dll' I PQ~"!FIL_Q.!STRIRUTIQN DIV ' NorT.O!ly .. ,,.... ..._-y ITI'i" ~ ~ tZ~/t50V DC sWCR U ZS/2:!0V DC SICR ZB HATCit t'NIT 2 

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Sketch 1: Electrical Layout of System (Unit 2, Unit 1 similar) OIP Phase 1 and Phase 2 Rev. 1 Page 56 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan l 4CCUII~LA~OR ~~~~ r-J:::>-1 _n 

                                                          >~,Bo~;u" L ACCUMULATOQ TAMS/                                                                                          .ANKS/

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Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Sketch 3: P&ID Layout of SA WA (prelimillary) II I -~.. UNfT 1 DCV I IIHRSW L r -----LIXIII'Y I Jl2. r~ 

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OIP Phase 1 and Phase 2 Rev. 1 Page 58 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System {HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 4: Failure Evaluation Table Table 4A: Wet Well HCVS Failure Evaluation Table Failure with Alternate Action Functional Failure Impact on Mode Failure Cause Alternate Action Containment Venting? Failure of Vent to Open Valves fail to open/close due to No action needed, power is already tied into station No on Demand Joss of normal AC power service battery via inverter for minimum 12 hours Failure of Vent to Open Valves fail to open/close due to Connect dedicated batteries to inverter via transfer No on Demand loss of alternate AC power (long switch for minimum 12 hours term) Failure of Vent to Open Val ves fail to open/close due to Recharge station service batteries with FLEX provided No on Demand complete loss of batteries (long generators, considering severe accident conditions term) Failure of Vent to Open Val ves fail to open/close due to No action needed, air can be supplied by accumulator No on Demand loss of normal pneumatic air tanks, which is sufficient for at least 8 cycles of F082 supply valve over first 24 hours. Failure of Vent to Open Valves fail to open/close due to Tie-in nitrogen cylinders to air system supporting No on Demand loss of alternate pneumatic air HCVS valves, replace bottles as needed. supply (long term) Failure of Vent to Open Valves fail to open/close due to Heroic action needed Yes on Demand SOV failure OIP Phase 1 and Phase 2 Rev. 1 Page 59 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 5: References I. Generic Letter 89-16, Installation of a Hardened Wetwell Vent, dated September I, 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-13-109, 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-20 12-02, Compliance with Order EA-12-050, Reliable Hardened Containment Vents, dated August 29, 2012
8. JLD-ISG-2013-02, Compliance with Order EA-13-109, 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-20 12-02: Compliance with Order EA-12-050, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents, ADAMS Accession No. ML12229A477, dated August 29, 2012 I0. NEI 12-06, Diverse and Flexible Coping Strategie * (FLEX) Implementation Guide, Revision 0, dated August 2012 II. NEI 13-02, Industry Guidance for Compliance with Order EA-13-1 09, Revision I, Dated Apri12015
12. NEI 13-06, Enhancements to Emergency Response Capabilities for Beyond Design Basis Accidents and Events, Revision 0, dated March 2014
13. NEI 14-0 I, 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 Mechanism.
17. NEI HCVS-FAQ-04, HCVS Release Point
18. NEI HCVS-FAQ-05, HCVS Control and 'Boundary Valves' I 9. 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 I

OIP Phase 1 and Phase 2 Rev. 1 Page 60 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan

23. NEI White Paper HCVS-WP-0 I, HCVS Dedicated Power and Motive Force
24. NEI White Paper HCVS-WP-02, HCVS Cyclic Operations Approach
25. NEI White Paper HCVS-WP-03, Hydrogen/CO Control Measures
26. NEI White Paper HCVS-WP-04, Missile Evaluation for HCVS Components 30 Feet Above Grade
27. IEEE Standard 344-2004, IEEE Recommended Practice for Seismic Qualification of Class IE Equipment for Nuclear Power Generating Stations,
28. Edwin I. Hatch EA-12-049 (FLEX) Overall Integrated Implementation Plan, Rev 0, February 20 13
29. Edwin I. Hatch EA-12-050 (HCVS) Overall Integrated Implementation Plan, Rev 0, February 20 13
30. Edwin I. Hatch EA-12-051 (SFP Ll) Overall Integrated Implementation Plan, Rev 0, February 20 13
31. Edwin I. Hatch Procedure 31EO-EOP-IOI-I, Emergency Containment Venting (Unit I)
32. Edwin I. Hatch Procedure 31EO-EOP-IOI-2, Emergency Containment Venting (Unit 2)
33. Edwin I. Hatch Procedure 31EO-EOP-104-I, Primary Containment Venting for H2 and 02 Control (U I)
34. Edwin I. Hatch Procedure 31 EO-EOP-104-2, Primary Containment Venting for H2 and 02 Control (U2)
35. Edwin I. Hatch Procedure 31 EO-EOP-0 12-1, U I PC Flowchart
36. Edwin I. Hatch Procedure 31EO-EOP-OI2-2, U2 PC Flowchart
37. Edwin I. Hatch Procedure 31EO-PCG-OOI-I, Ul PC-G Flowchart
38. Edwin I. Hatch Procedure 31EO-PCG-OOI-2, U2 PC-G Flowchart
39. Edwin I. Hatch Procedure 3IEO-SAG-00l-l, Ul SAG-01 Flowchart
40. Edwin I. Hatch Procedure 31EO-SAG-OOI-2, U2 SAG-01 Flowchart 4I. Edwin I. Hatch Procedure 3I EO-SAG-002-1, U I SAG-02 Flowchart
42. Edwin I. Hatch Procedure 3IEO-SAG-002-2, U2 SAG-02 Flowchart
43. Edwin I. Hatch Procedure 31 EO-TSG-00 l-0, Technical Support Guidelines
44. Edwin I. Hatch Procedure 3IEO-TSG-002-0, Technical Support Appendix J
45. Southern Nuclear Procedure NMP-EP-403, Figure I, EMG/EDMG Flowchart
46. Consideration of Additional Requirements for Containment Venting Systems for Boiling Water Reactors with Mark I and Mark II Containments, SECY-I2-0l57, MLI2344A030
47. NUREG/CR-7110, VI, Rl, State-of-the-Art Reactor Consequence Analyses (SOARCA)

Project: Peach Bottom Integrated Analysis, ML I3I50A053 OIP Phase 1 and Phase 2 Rev. 1 Page 61 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan

48. JLD-ISG-20 15-0 I, Compliance with Phase 2 of Order EA-13-1 09, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions, dated March 2015
49. NEI FAQ HCVS-10, Severe Accident Multiple Unit Response
50. NEI FAQ HCVS-11, Plant Response During a Severe Accident
51. NEI FAQ HCVS-12, Radiological Evaluations on Plant Actions Prior to HCVS Initial Use
52. NEI FAQ HCVS-13, Severe Accident Venting Actions Validation
53. NRC Endorsement of "Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Template, " Revision I, dated September 22, 2015, and Frequently Asked Questions (FAQs) 10, II, 12, and 13 (ADAMS Accession No. MLI5273AI41), dated October 8, 2015 OIP Phase 1 and Phase 2 Rev. 1 Page 62 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 6: Changes/Updates to this Overall Integrated Implementation Plan This Overall Integrated Plan has been updated in format and content to encompass both Phase 1 and Phase 2 of Order EA-13-1 09. Any significant changes to this plan will be communicated to the NRC staff in the 6 Month Status Reports OIP Phase 1 and Phase 2 Rev. 1 Page 63 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 7: List of Overall Integrated Plan Open Items OIP Open Action Comment Item 1 Determine location of Dedicated HCVS Battery transfer Audit item per ISE switch 2 Determine location of back-up nitrogen bottles Audit item per ISE 3 Evaluate location of Portable DG for accessibility under Audit item per ISE Severe Accident HCVS use 4 Confirm suppression pool heat capacity Audit item per ISE 5 Determine location of HCVS Remote Operating Station Audit item per ISE (ROS) 6 State which approach or combination of approaches Plant Audit item per ISE 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 NEt Audit item per ISE HCVS-FAQ-05 8 Identify qualification method used for HCVS instruments Audit item per ISE 9 Evaluate HCVS monitoring location of Portable DG for Audit item per ISE accessibility, habitability, staffing sufficiency, and communication capability with Vent under Severe Accident HCVS 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 Audit item per ISE criteria OIP Phase 1 and Phase 2 Rev. 1 Page 64 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan ISE Action (OIP section reference) Open Items

1. Make available for NRC staff audit the location of the ROS's. OIP Item 5 (Section 3.2.1, Section 3.2.2.4, Section 3.2.2.5, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.2, Section 3.2.6)
2. Make available for NRC staff audit the location of the OIP Item 1 dedicated HCVS battery transfer switch. (Section 3.2.1, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.2, Section 3.2.6)
3. Make available for NRC staff audit documentation of the OIP Item 2 HCVS nitrogen pneumatic system design including sizing and location. (Section 3.2.1, Section 3.2.2.4, Section 3.2.3.1, Section 3.2.3.2, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.1, Section 3.2.5.2, Section 3.2.6)
4. Make available for NRC staff audit the deployment location of OIP Item 3 the portable diesel generators. (Section 3.2.1, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.2, Section 3.2.6)
5. Make available for NRC staff audit an evaluation of Related to OIP Item 5 temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment. (Section 3.2.1, Section 3.2.2.4, Section 3.2.2.5, Section 3.2.2.1 0, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.2, Section 3.2.6)
6. Make available for NRC staff audit analyses demonstrating OIP Item 4 that HCVS has the capacity to vent the steam/energy equivalent of one percent of licensed/rated thermal power (unless a lower value is justified), and that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit. (Section 3.2.2.1, Section 3.2.2.2)
7. Make available for NRC staff audit the descriptions of local Related to OIP Item 8 conditions (temperature, radiation and humidity) anticipated during ELAP and severe accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, etc.) required for HCVS venting including confirmation that the components are capable of OIP Phase 1 and Phase 2 Rev. 1 Page 65 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan performing their functions during ELAP and severe accident conditions. (Section 3.2.2.5, Section 3.2.2.3, Section 3.2.2.9, Section 3.2.2.1 0)

8. Make available for NRC staff audit the final sizing evaluation New Item for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation. (Section 3.2.2.4, Section 3.2.3.1, Section 3.2.3.2, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.1, Section 3.2.5.2, Section 3.2.6)
9. Make available for NRC staff audit documentation that OIP Item 9 demonstrates adequate communication between the remote HCVS operation locations and HCVS decision makers during ELAP and severe accident conditions. (Section 3.2.2.5)
10. Provide a description of the final design of the HCVS to OIP Item 6 address hydrogen detonation and deflagration. (Section 3.2.2.6)
11. Provide a description of the strategies for hydrogen control OIP Item 6 that minimizes the potential for hydrogen gas migration and ingress into the reactor building or other buildings. (Section 3.2.2.6}
12. Make available descriptions of design details that minimize OIP Item 7 unintended cross flow of vented fluids within a unit and between units. (Section 3.2.2.7)
13. Make available for NRC staff audit descriptions of all Related to OIP Item 8 instrumentation and controls (existing and planned) necessary to implement this order including qualification methods. (Section 3.2.2.9)
14. Make available for NRC staff audit documentation of an Utilizing existing PCIVs that evaluation verifying the existing containment isolation valves, perform a Design Basis relied upon for the HCVS, will open under the maximum function. Per NEI13-02 no expected differential pressure during BDBEE and severe further evaluation required accident wetwell venting. (Section 3.2.2.9)
15. Make available for NRC staff audit the control document for OIP Item 11 HCVS out of service time criteria. (Section 3.4.1)

OIP Phase 1 and Phase 2 Rev. 1 Page 66 of66 December 6, 2015

Charles R. Pierce Southern Nuclear Regulatory Affairs Drrector Operating Company, Inc. a\ 40 Inverness Center Parkway Post Office Box 1295 Birmingham, AL 35201 Tel 205.992 .7872 SOUTHERN Fax 205.992 .7601 NUCLEAR DEC 2 3 2015 A SOUTHERN COMPANY Docket Nos.: 50-321 NL-15-2121 50-366 U. S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D. C. 20555-0001 Edwin I. Hatch Nuclear Plant - Units 1 and 2 Third Six-Month Status Report of the Implementation of the Commission Order with Regard to Requirements for Reliable Hardened Containment Vents (EA-13-1 09)

References:

1. NRC Order Number EA-13-109, Order Modifying Licenses with Regar d to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions, dated June 6, 2013.
2. NEI13 -02, Industry Guidance for Compliance with NRC Order EA-13-109, To Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accide nt Conditions, Revision 0, dated November 2013.
3. NRC Interim Staff Guidance JLD-ISG-2013-02, Compliance with Order EA-13-109, Order Modifying Licenses with Regar d to Reliable Hardened Containmen t Vents Capable of Operation Under Severe Accide nt Conditions, Revision 0, dated November 2013.
4. SNC Letter, Edwin I. Hatch Nuclear Plant - Units 1 and 2 Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licens es with Regard to Requirements for Reliable Hardened Containment Vents ( EA-13
                                                                             -109), dated June 27, 2014.
5. NRC letter, Edwin I. Hatch Nuclear Plant Units, 1 and 2 -Inter im Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 1 of Order EA-13
                                                                           -109 (Severe Accide nt Capable Hardened Vents), dated March 25,20 15 (ML14335A137).
6. NEI13 -02, Industry Guidance for Compliance with NRC Order EA-13-109, To Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accide nt Conditions, Revision 1, dated April 2015.
7. NRC Interim Staff Guidance JLD-ISG-2015-01, Compliance with Order EA-13-109, Order Modifying Licenses with Regar d to Reliable Hardened Containmen t Vents Capable of Operation Under Severe Accide nt Conditions, Revision 1, dated April 2015.
8. NRC Endorsement of "Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Template," Revision 1, dated Septe mber 22,20 15, and Frequently Asked Questions (FAQs) 10, 11, 12, and 13, dated October 8, 2015 La?ies and Gentlemen:

On June 6, 2013, the Nuclear Regulatory Commission (NRC) issued an Order (Reference 1) to Southern Nuclear Operating Company (SNC) . Reference 1 was immediately effective and

U.S. Nuclear Regulatory Commission NL-15-2121 Page2 directs the Edwin I. Hatch Nuclear Plant - Units 1 and 2 (HNP) to install a reliable hardened venting capability for pre-core damage and under severe accident conditions, including those involving a breach of the reactor vessel by molten core debris. Specific requirements are outlined in Attachmen t 2 of Reference 1. In addition, Reference 1 also required submission of a Phase 1 overall integrated plan pursuant to Section IV, Condition D, and status reports at six-month intervals thereafter. SNC submitted the overall integrated plan (OIP) by letter dated June 27, 2014 (Reference 4). This letter is being submitted to satisfy the requirements of providing the third six-month update for Phase 1 of the Order in accordance with Section IV, Condition D.3, of Reference 1, and the OIP for Phase 2 of the Order in accordance with Section IV, Condition D.2 of Reference 1. The third six-month update for Phase 1 of the Order is incorporated into the HCVS Phase 1 and Phase 2 overall integrated plan document which provides a complete updated Phase 1 OIP, a list of the Phase 1 OIP open items, and addresses the NRC Interim Staff Evaluation open items for Phase 1 contained in Reference 5. Future six-month status reports will provide the updates for both Phase 1 and Phase 2 OIP implementation in a single status report. This letter contains no new NRC commitments. If you have any questions, please contact John Giddens at 205.992.7924. Mr. C. A. Pierce states he is the Regulatory Affairs Director for 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, C.f{ ~ C. A. Pierce Regulatory Affairs Director CRP/JMG/GLS 

                                                                            '2015.

My commission expires: /a -!-,;l a I '1

Enclosure:

Hatch Hardened Containme nt Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan, Revision 1

U.S. Nuclear Regulatory Commissio n NL-15-2121 Page 3 cc: Southern Nuclear Operating Company Mr. S. E. Kuczynski, Chairman, President & CEO Mr. D. G. Bost, Executive Vice President & Chief Nuclear Officer Mr. D. R. Vineyard, Vice President - Hatch Mr. M. D. Meier, Vice President - Regulatory Affairs Mr. B. J. Adams, Vice President - Engineering Mr. D. R. Madison, Vice President - Fleet Operations Mr. G. L. Johnson, Regulatory Affairs Manager- Hatch RType: CHA02.004 U. S. Nuclear Regulatory Commissio n Mr. V. M. McCree, Director of the Office of Nuclear Reactor Regulations Mr. L. D. Wert, Regional Administra tor (Acting) Mr. R. E. Martin, NRR Senior Project Manager- Hatch Mr. D. H. Hardage, Senior Resident Inspector- Hatch Ms. J. A. Kratchman, NRRIJLD/P MB Mr. E. E. Bowman, NRR/DPR/ PGCB State of Georgia Mr. J. H. Turner, Director- Environme ntal Protection Division

Edwin I. Hatch Nuclea r Plant - Units 1 and 2 Third Six-Mo nth Status Report of the Implem entation of the Commi ssion Order with Regard to Requirements for Reliable Hardened Contain ment Vents (EA-13-109) Enclosu re Hatch Hardened Contain ment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan, Revisio n 1

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 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 EA-13-109, Option B.2 Part 3.1 Boundary Conditions for SAWA Part 3.1A Boundary Conditions for SAWAIS AWM Part 3.18 Boundary Conditions for SAWAIS ADV Part 4: Programmatic Controls, Training , Drills and Maintenance Part 5: Implementation Schedule Milestones Attachment 1: HCVS/S AWAISA DV Portable Equipment Attachment 2A: Sequence of Events HCVS Attachment 2.1.A: Sequence of Events Timelin e- SAWA I SAWM Attachment 2.1.8: Sequence of Events Timeline - SADV Attachment 2.1.C: SAWA I SAWM Plant-Specific Datum Attachment 3: Conceptual Sketches Attachment 4: Failure Evaluation Table Attachment 5: References : Changes/Updates to this Overall Integrated Implementation Plan : List of Overall Integrated Plan Open Items OIP Phase 1 and Phase 2 Rev. 1 Page 1 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 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 I 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, 2018, 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, 20 I 7, or June 30, 2019, whichever comes first.")

The NRC provided an acceptable approach for complying with Order EA-13-1 09 through Interim Staff Guidance (JLD-ISG-2013-02 issued in November 2013 and JLD-ISG-2015-01 issued in April2015 ). The ISG endorses the compliance approach presented in NEI 13-02 Revisions 0 and I, 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-13-1 09, the NRC staff will use the methods described in the ISGs to evaluate licensee compliance as presented in submittals required in Order EA-13-1 09. 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 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 and JLD-ISG-2015-01. Six month progress reports will be provided consistent with the requiremenfs of Order EA 13-109. 1 OIP Phase 1 and Phase 2 Rev. 1 Page 2 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan The submittals required are:

  • OIP for Phase I of EA-13-1 09 was required to be submitted by Licensees to the NRC by June 30, 2014. The NRC requires periodic (6 month) updates for the HCVS actions being taken.

The first update for Phase I was due December 2014, with the second due June 2015.

  • OIP for Phase 2 of EA-13-1 09 is required to be submitted by Licensees to the NRC by December 31, 2015. It is expected the December 2015 six month update for Phase 1 will be combined with the Phase 2 OIP submittal by means of a combined Phase I and 2 OIP.
  • Thereafter, the 6 month updates will be for both the Phase I and Phase 2 actions until complete, consistent with the requirements of Order EA-13-109.

Note: At the Licensee's option, the December 2015 six month update for Phase I may be independent of the Phase 2 OIP submittal, but will require separate six month updates for Phase 1 and 2 until each phase is in compliance. The Plant venting actions for the EA-13-1 09, Phase 1, 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)(some plants have a designated Primary Operating Station (POS) that will be treated as the main operating location for this order) 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 and Level 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 hours 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.

The Phase 2 actions can be summarized as follows:

  • Utilization of Severe Accident Water Addition (SAWA) to initially inject water into the Reactor Pressure Vessel (RPV) or Drywell.
  • Utilization of Severe Accident Water Management (SAWM) to control injection and Suppression Pool level to ensure the HCVS (Phase 1) wetwell vent (SAWV) will remain functional for the removal of the decay heat from the core from containment.
  • Ensure that the decay heat can be removed from the containment for seven (7) days using the HCVS or describe the alternate method(s) to remove decay heat from the containment from the time the HCVS is no longer functional until alternate means of decay heat removal are established that make it unlikely the drywell vent will be required for containment pressure control.
  • The SAWA and SAWM actions will be manually activated and controlled from areas that are accessible during severe accident conditions.

OIP Phase 1 and Phase 2 Rev. 1 Page 3 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan

  • Parameters measured should be Drywell pressure, Suppression Pool level, SAWA flowrate and the HCVS parameters listed above.
  • Alternatively SA WA and a Severe Accident Capable Drywell Vent (SADV) strategy may be implemented to meet Phase 2 of Order EA 109.

Part 1: General Integrated Plan Elements and Assum ptions Extent to which the guidance, J LD-ISG-2013-02, JLD-ISG-2015-01 and NEI 13-02 (Revision 1), 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, JLD-ISG-2015-01 Compliance will be attained for E.l. Hatch Units 1&2 (Plant Hatch) with no known deviations to the guidelines in JLD-ISG-2013-02, JLD-ISG-2015-01 and NEI 13-02 for each phase as follows:

  • The Hardened Containment Vent System (HCVS) will be comprised of installed and portable equipmen t and operating guidance:
  • Severe Accident Wetwell Vent (SAWV) - Permanently installed vent from the Suppression Pool to the meteorological stack
  • Severe accident Water Addition (SAW A)- A combination of permanently installed and portable equipment to provide a means to add water to the RPV following a severe accident and monitor system and plant conditions.
  • Severe Accident Water Management (SA WM) strategies and guidance for controllin g the water addition to the RPV for the sustained operating period. (reference attachment 2. l.D)
  • Phase 1 (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 l st Quarter 2017 (Unit 2), lst Quarter 2018 (Unit 1)
  • Phase 2 (alternate strategy): by the startup from the fi rst refuelin g outage that begins after June 30, 2017 or June 30, 2019, whichever comes first. Currently scheduled for 1st Quarter 2019 (Unit 2), 1st Quarter 2018 (Unit 1)

If deviations are identified at a later date, then the deviations will be communicated in a future 6 month update following identification. State Applica ble Extreme External Hazard from NEI 12-Q6, Section 4.0-9.0 List resultant determination of screened in hazards from the EA 049 Complianc e. Ref: NEI 13-02 Section 5.2.3 and 0.1.2 OIP Phase 1 and Phase 2 Rev. 1 Page 4 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions 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 assumpti ons to implement NEI 13-02 HCVS, Phase 1 and 2 Actions.

Provide key assumptions associated with implementation of HCVS Phase I and Phase 2 Actions Ref: NEI 13-02, Revision 1, Section 2 NEI 12-06 Revision 0 Mark 1111 Generic EA-13-1 09 Phase 1 and Phase 2 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 4 049-4. 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 sensitive at a time greater than 1 hour) an ELAP is declared and actions begin as defined in EA-12-049 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 hours with a calculation limiting value of 13.35 hours). The power supply scheme for the HCVS shall be in accordance with EA-13-109 and the applicable guidance. (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 hours 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, notification, SFP level and makeup, security response, opening doors for cooling, and initiating conditions for the event, can be credited as previously evaluated for FLEX. (refer to assumption 109-02 below for clarity on SAWA)(HCVS-FAQ-11) Applicable EA-13-1 09 generic assumptions : I 09-01. 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). This is further referenced in HCVS-FAQ-12. 109-02. Portable equipment can supplement the installed equipment after 24 hours provided the portable equipment credited meets the criteria applicable to the HCVS . An example is use of FLEX portable air supply e~uipment 1 that is credited to recharge air lines for HCVS components after 24 hours. The FLEX portable air supply used must be demonstrate d to meet the "SA Capable" criteria that are defined in NEI 13-02 Section 4.2.4.2 and OIP Phase 1 and Phase 2 Rev. 1 Page 5 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions Appendix D Section D.l.3. This assumption does not apply to Phase 2 SAW A/SAWM because SAW A equipment needs to be connected and placed in service within 8 hours from the time of the loss of RPV injection. (Reference HCVS-FAQ-12) I09-03. 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). I 09-04. Existing containment components design and testing values are governed by existing plant primary 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). 109-05. 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 ). I 09-06. 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-0 I) This assumption does not apply to Phase 2 SAW A/SA WM because SAWA equipment needs to be connected and placed in service within 8 hours from the time of the loss of RPV injection and will require more than minimal operator action. I 09-07. 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-0 I). This assumption does not apply to Phase 2 SAWA/SA WM because SAWA equipment is not dedicated to HCVS but shared to support FLEX functions. This is further addressed in HCVS-FAQ-11. I 09-08. 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. MAAP Version 5 was used to develop EPRI Technical Report 3002003301 to support drywell temperature response to SAWA under severe accident conditions. 109-09. 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 I 09 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. This assumption does not apply to Phase 2 SA WM because SA WM requires changes to the EPG/SAGs per approved issue from the BWROG Emergency Procedures Committee. 109-12. Under the postulated scenarios of order EA-13-109 the Control Room is adequately protected from excessive radiation dose due to its distance and shielding from the reactor (per General Design Criterion (GDC) I 9 in I OCFR50 Appendix A) and no further evaluation of its use as the preferred HCVS control location is required provided that the HCVS routi~g is a sufficient distance away from the MCR or is shielded tp minimize impact to the MCR dose. In addition, adequate protective clothing and respiratory protection is available if required to address contamination issues. (reference HCVS-FAQ-01 and HCVS-FAQ-09) OIP Phase 1 and Phase 2 Rev. 1 Page 6 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumptions I 09-13 . The suppression poollwetwell of a BWR Mark 1/11 containment is considered to be bounded by assuming a saturated environment for the duration of the event response because of the water/steam interactions. I 09- 14. RPV depressurization is directed by the EPGs in all cases prior to entry into the SAGs (reference NEI 13-02 Rev I section 1.1.3) 109- 15 . The Severe Accident impacts is assumed on one unit only due to the site compliance with NRC Order EA-12-049, However, each BWR MK I and II under the assumptions of NRC Order EA- 13-1 09 ensure the capability to protect containment exists for each unit. (HCVS-FAQ-10) 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 disk will be manually breached within 7.3 hours 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. OIP Phase 1 and Phase 2 Rev. 1 Page 7 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1 : General Integrated Plan Elements and Assumptions N~ Plant E. I. Hatch Map of Protected Area and Surrounding Area Main Control Room IEL. 164' -0) Figure 1-1 Plant Hatch Site Layout OIP Phase 1 and Phase 2 Rev. 1 Page 8 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 1: General Integrated Plan Elements and Assumpt ions 

                                                                    §    D===t 5

unit 1 Electrical If~i I 11 () ("ooocJohCO...T Figure 1-2 Figure 1-3 Hatch Reactor Building Elevation View Hatch Control Building Ground Floor (EL 130) OIP Phase 1 and Phase 2 Rev. 1 Page 9 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 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 time line attachment. See attached sequence of events time line (Attachment 2) Ref: EA-13-109 Section 1.1.1, 1.1.2, 1.1.3/ 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. Initial 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 Location I Notes Component Hand switches located in the or at the Remote MCR Operating Station (ROS), depending on where operator of HCVS is stationed 

                               =~~~--~-~~---- +~-~~~~~--~~------r-------------------

Panels in MCR containing PCIV interlocks Hand switch located in the Unit 2 only. MCR for condensate drain Unit 1 N/A valve And at ROS panel Manual hand wheels for valves Not required during at the argon bottle and at the SA event. Only piping at the argon bottle station required if I performing early venting for FLEX OIP Phase 1 and Phase 2 Rev. 1 Page 10 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent

5. Close argon cylinder valve & Manual hand wheels for valves Not required during valve I/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
          ----~--~--~---~~==~--------r~~--~~~*-------- --~~~--~~-------
6. Open Wetwell PCIVs Hand switches located in the And at ROS l/2T48-F318 & 1/2T48-F326 MCR
7. Open HCVS vent control Hand switch for valve in the And at ROS valve I/2T48-F082 MCR
8. Align power supplies for all Instruments and controls located Prior to depletion of valves and instruments via in the MCR or Control Building station batteries, Inverters I/2R44-S006 & actions will be l/2R44-S007. required to swap to dedicated HCVS power supply.
          ------~--~---------~*----~---- ~~---------~--~~-----r~-----~~----~
9. Replenish pneumatics with Primary nitrogen bottles for Prior to depletion of replaceable nitrogen bottles FLEX response and early the pneumatic venting are located in the sources actions will Reactor Building. Back-up be required to nitrogen bottles are installed in connect back-up the Control Building to ensure sources at a time severe accident pneumatic greater than 24 supply access. hours.
10. Re-align power supplies for all Instruments and controls located Prior to depletion of valves and instruments via in the MCR or Control Building the installed power Inverters I/2R44-S006 & sources actions will l/2R44-S007 . be required to connect back-up sources at a time greater than 24 hours.

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 failure of RCIC I after a black start where failure occurs because of subjectiyety assuming over injection.
3. Case 3 is based on NUREG-1935 (SOARCA) results for a prolonged SBO (or ELAP) with the loss ofRCIC case without black start.

OIP Phase 1 and Phase 2 Rev. 1 Page 11 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent The followin g is a discussion of time constraints identified in Attachment 2A 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 rel iable 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 hours, HCVS battery capacity will be available to extend past 24 hours. 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 hours is acceptable because the actions can be performed any time after declaration of an ELAP ( 1 hour) until the venting is needed at 7.3 hours 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 2A.

  • At 12 hours, 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 hours, HCVS battery capacity will be available to extend past 24 hours. 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 hours.
  • At 24 Hours, temporary generators will be installed and connected to the pigtail to power up battery chargers to supply power to HCVS critical components/instruments; time sensitive at a time greater than 25 hours (>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 hours. DG will be deployed 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 hours 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. Modifications will be implemented to facilitate the connections and operational actions required to supply power within 10 hours 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 hours for HCVS operation. For Phase 2 applicability, the 8-10 hours will change to 6-7 hours, since it provides power to the SAWA Valves, and will be validated by the Phase 2 Verification and Validation activity, thus providing power by 7 hours,

  • 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 hours assuming a minimum of 8 HCVS cycles. Thus 24 hours 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 hourl OIP Phase 1 and Phase 2 Rev. 1 Page 12 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Discussion of radiological and temQerature constraints identified in Attachment 2A

  • At <7.3 hours, 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- I 2-049 to a value Jess than or equal to PSP.
  • At 12 hours, 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 I -1).

[OPEN ITEM 1: Determine location of dedicated HCVS batter~ transfer switch - Switch is located on ground elevation of Control Building]

  • 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 in the Control Building or yard area.

[OPEN ITEM 2: Determine location of back-uQ nitrogen bottles- Nitrogen Bottles will be located in the Control Building]

  • 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 hours for HCVS operation and at 8 hours for SAWA operation (refer to section 3. I of this OIP). Current battery durations are calculated to last greater than 26 hours. 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 hours 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 .

[OPEN ITEM 3: Evaluate location of QOrtable DG for access ibilit~ under Severe Accident HCVS use- Portable DG will be staged and OQerated adjacent to the Reactor Building substantiall~ awa~ from the HCVS QiQing or the main stack release point]

  • At >24 hours, power supply 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 Si!,.e and Basis (EA-13-109 Section 1.2.1 I NE113-02 Section4.1.1~ 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 Caeaci!J. (EA-13-109 Section 1.2.1 I NEI 13-02 Section 4.1.1l Indicate any exceptions to the 1% decay heat r1moval criteria, including reasons for the exception. Provide lthe heat capacity of the suppression pool in terms of time versus pressurization capacity, assuming suppression pool is the injection source. OIP Phase 1 and Phase 2 Rev. 1 Page 13 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Vent Path and Discharge (EA-13-109 Section1.1.4, 1.2.2 I NE/13-02 Section 4.1.3, 4.1.5 and Appendix FIG) Provides a description of Vent path, release path, and impact of vent path on other vent element items. Power and Pneumatic Supplv Sources (EA-13-109 Section1.2.5 & 1.2.6 I NE/13-02 Section4.2.3, 2.5, 4.2.2, 4.2.6, 6.1) Provide a discussion of electrical power requirements, including a description of dedicated 24 hour 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 hour 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 of Control Panels (EA-13-109 Section1.1.1, 1.1.2, 1.1.3, 1.1.4, 1.2.4, 1.2.5 I NE/13-02 Section4.1.3, 4.2.2, 4.2.3, 4.2.5, 4.2.6, 6.1.1 and Appendix 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. Hvdrogen (EA-13-109 Section 1.2.10, 1.2.11, 1.2.12 I NE/13-02 Section 2.3,2.4, 4.1.1, 4.1.6, 4.1.7, 5.1, & Appendix H) State which approach or combination of approaches the plallt will take to address the control offlammable gases, clearly demarcating the segments of vent system to which an approach applies Unintended Cross Flow of Vented Fluids (EA-13-109 Section 1.2.3, 1.2.12 I NE/13-02 Section 4.1.2, 4.1.4, 4.1.6 and Appendix H) Provide a description to eliminate/minimize unintended cross flow ofventedfluids with emphasis on inteifacing ventilation systems (e.g. SGTS). What design features are being included to limit leakage through inteifacing valves or Appendix J type testing features? Prevention o{/nadvertent Actuation (EA-13-109 Section1.2.71N E/13-02 Section4.2.1) The HCVS shall include means to prevent inadvertent actuation Component Qualifications (EA-13-109 Section2.1 I NE/13-02 Section5.1, 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 ofHCVS (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 Section2.2 I NE/13-02 Section5.2, 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 peiformance that is capable of ensuring HCVS functionality followin g a seismic event. (reference /SG-JLD-2012-01 and /SG-JLD-2012-03 for seismic details.) The components including instrumentption external to a seismic category I (or equivalent building or enclosure should be designed to meet the external haza'rds that screen-in for the plant as defined in guidance NE/12-06 1 as endorsed by JLD-ISG-12-01 for Order EA-12-049. OIP Phase 1 and Phase 2 Rev. 1 Page 14 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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 requiremellfs, 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 pe1jormance 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 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 and frequency ranges). Such testing and analysis should be similar to that pelformedf or the plant licensing basis. Vent Size and Basis The HCVS wetwell path is designed for venting steam/energy at a nominal capacity of I% 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 I% 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 hours. 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 hours following the ELAP event. At about 12 hours, power can be transferred to the HCVS dedicated batteries t~at will supply power for an additional time of> 12 hours. At ~4 hours, 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 OIP Phase 1 and Phase 2 Rev. 1 Page 15 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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 hours, 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 hours, backup nitrogen provided by nitrogen supply bottles will be manually valved-in and replenished as needed. I. 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 (SOY) 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 hours. Beyond the first 24 hours, 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 eight valve operating cycles for the HCVS valve for the first 24 hours.

2. Following the initial 24 hour period, additional motive force will be supplied from nitrogen bottles that will be staged at a gas cylinder rack located (in the control building) such that radiological impacts are not an issue. Additional bottles can be brought in as needed.
3. An a sessment 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 2A.

[OPEN ITEM 5: Determine location of HCVS Remote Operating Station CROS) for both units. Utilize HCVS-FAQ-01 in the response. - ROS will be located at the 147'elevation of the Control Building, one floor below the elevation of the MCRJ

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 the 147' elevation of the Control Building, one floor below the elevation of the MCR . I I [OPEN ITEM 5: Determine location of HCVS Remote Operatin g Station CROS) for both units. Utilize OIP Phase 1 and Phase 2 Rev. 1 Page 16 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent HCVS-FAQ-01 in the response- ROS will be located at the 147'elevation of the Control Building, one floor below the elevation of the MCR.l Hydrogen As is required by EA- I 3- I 09, Section 1.2. I I, 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- Plant Hatch plans to use option I of the endorsed white paper HCVS-WP-03 and power up the mixing chamber fan in the base of the metrological stack.] 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 SOY must be energized to allow the motive air to open the valve. Specifically: I. The PCIS control circuit will be used during all "design basis" operating modes including all design basis transients and accidents.

2. 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 .]

3. 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. Main stack dilution fans will be repowered prior to venting operations for severe accident with core debris ex-vessel.

Prevention of Inadverten t Actuation EOPIERG 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.

  • 1fhe features that prevent inadvertent actuation are two PCIV' ~ in series powered from different divisions, a rupture disk, or key lock switches. Procedures also provide clear guidance to not circumvent containment integrity by simultaneou sly opening Suppression Pool and drywell vent valves during any design basis transient OIP Phase 1 and Phase 2 Rev. 1 Page 17 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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-13-109 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 IOCFR 100. 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 (EQ) 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* HCVS Process Temperature IS09001/ IEEE 344-2004 I Demonstration HCVS Process Radiation Monitor IS09001/ IEEE 344-2004 I Demonstration HCVS Process Valve Position IS09001/ IEEE 344-2004 I Demonstration HCVS Pneumatic Supply Pressure IS09001/ IEEE 344-2004/ Demonstration HCVS Electrical Power Supply Availability IS09001/ IEEE 344-2004 I Demonstration

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

OIP Phase 1 and Phase 2 Rev. 1 Page 18 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent [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/Alternate 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 Joss 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 hours will be provided by two air accumulator tanks and station service batteries, supplemented by installed backup battery power sources. Beyond the first 24 hours, 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 Drywell Pressure and Suppression Pool 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 rugged performance 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 l, SS and 300# ASME or B3l.1, NEMA 4, etc.) for the plant and to ensure functionality following a design basis earthquake. The torus hardened vent (THY) 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 implemeqted 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 upgrad~ the THV to a hardened containment vent system (HCVS), will meet the requirements of Order EA-13-109 and remain OIP Phase 1 and Phase 2 Rev. 1 Page 19 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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. (reference HCVS-FAQ-08) 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 required. (reference HCVS-WP-04) 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-13-1 09 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:

  • 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;
  • ade.quacy 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 IE 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.

OIP Phase 1 and Phase 2 Rev. 1 Page 20 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent 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-13-109 Section 1.1.4 I NEI 13-02 Section 2.2 First 24 Hour Coping Detail Provide a general description of the venting actions for first 24 hours using installed equipment including station modifications that are proposed. Ref: EA-13-109 Section 1.2.6 I 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 BDBEE hazards identified in part I of this OIP. Initial 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 in response to this Order. Both locations minimize plant operators' exposure to adverse temperature and radiological conditions and are protected from hazards assumed in Part I of this report. Permanently installed power and motive air/gas capability will be available to support operation and monitoring of the HCVS for 24 hours. Permanently installed equipment will supply air and power to HCVS for 24 hours 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 8 open/close cycles under ELAP conditions over the first 24 hours 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 PC IV s 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 val ve is normally key-locked closed and has a rupture disc located downstream. This rupture disc has a burst set pressure above the header pressure (at the disc) 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 than24 hours using portable and installed equipment including station modifications that are prolfsed. J Ref: EA-13-109 Section 1.2.4, 1.2.8 I NEI 13-02 Section 4.2.2 OIP Phase 1 and Phase 2 Rev. 1 Page 21 of 66 Decembe r 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Part 2 Boundary Conditio ns for WW Vent: BDBEE Venting After approximately 24 hours, 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 hours. 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 I 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 hours following the ELAP event (less than 3 planned actuations for FLEX), additional bottles can be connected to support sustained operation. After 24 hours, 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. NEI 13-02 §6.1.2 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-00 1-0, Technical Support Guidelines; 31 EO-EOP-1 01-1/2, Emergency Containment Venting; and, 31 EO-EOP-104-112, 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 nitrogen bottles for pneumatic support of the HCVS air actuators for the first 72 hours following an ELAP event.
  • Provide a means to manually breach the rupture disc in the HCVS header to allow for flow.

EA- 13-109 Modifications

  • Install dedicated batteries and disconnect switches to supply power to HCVS for the second 12 hours 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) modification s listed above (rupture disc instrumentation). I I

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

OIP Phase 1 and Phase 2 Rev. 1 Page 22 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: BDBEE Venting 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: Ke1: Parameter Comuonent Identifier Indication Location HCVS Effluent temperature 112T48-N150 MCRIROS HCVS Pneumatic supply pressure 1P52-N060, 2P52-N030 MCRIROS HCVS valve position indication 1/2T48-F318, 1/2T48-F326, MCRIROS 1/2T48-F081, 112T48-F082, 1T46-F005, 2T46-F002A/B , 2T48-F085 Rupture Disc Pressure 112T48-R030 Reactor Building 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): Ke1: Parameter Comuonent Identifier Indication Location Drywell pressure I/2T48-R608/R609 MCR Torus pressure I/2T48-R608/R609 MCR Torus water temperature 112T47-R611/R612 MCR Torus level 1/2T48-R607 AlB MCR Reactor pressure I /2C32-R605A/B MCR Drywell radiation 112T48-R601A/B MCR HCVS indications for HCVS pneumatic supply pressure and HCVS effluent temperature will be installed in the MCR to comply with EA-13-109. Notes: None I I OIP Phase 1 and Phase 2 Rev. 1 Page 23 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS} Phase 1 and 2 Overall Integrated Plan Part 2: Boundary Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: BDBEE Venting Part 2: Boundary Conditions for Wet Well Vent 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 NEI 13-02 Section 2.3 First 24 Hour Coping Detail Provide a general description of the venting actions for first 24 hours 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. Initial 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 Part 2 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 a ROS to be installed as part of the response to this Order. Both locations minimize plant operators' exposure to adverse temperature and ra9iological conditions and are protected from hazards assumed in Part 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 mon itoring of the HCVS for 24 hours. System control:

1. Active: PCIVs are operated in accordance with EOPs to control containment pressure. The HCVS is designed for a minimum of 8 open/close cycles of the isolation valve under ELAP conditions over the first 24 hours following an ELAP. HCVS venting will be directed per the SAMGs. Jumpers will be used to override the containment isolation circuit on the PCIVs needed to vent containment.
u. Passive: Inadvertent actuation protection is provided by the current containment isolation circuitry
                !associated with the PCIVs used to operate the HCVS . In ad9ition, 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 (at the disc) expected during a design basis event.

OIP Phase 1 and Phase 2 Rev. 1 Page 24 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: Severe Accident Venting Greater Than 24 Hour Coping Detail Provide a general description of the vellfing actions for greater than 24 hours 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 I of this report. Connections will be pre-engineered quick disconnects or similar arrangement to minimize manpower resources. After 24 hours, 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 hours, available personnel will be able to connect supplemental nitrogen to the HCVS if greater than 8 HCVS cycles have occurred or the pneumatic pressure is low. Sufficient nitrogen bottles will be staged to support operations for up to 72 hours 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 gost 24 hour 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 implementatio n The operation of the HCVS is governed the same for SA conditions as for BDBEE conditions, except there is no 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 other~ will be newly installed (to comply with the vent order) I OIP Phase 1 and Phase 2 Rev. 1 Page 25 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System {HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundarl£ Conditions for Wet Well Vent 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: Ke1: Parameter Com~onent Identifier Indication Location HCVS effluent temperature I/2T48-NI50 MCRIROS HCVS pneumatic supply pressure I P52-N060, 2P52-N030 MCRIROS HCVS valve position indication 1/2T48-F318, I/2T48-F326, MCRIROS I/2T48-F081, I/2T48-F082, I T46-F005, 2T46-F002A/B, 2T48-F085 HCVS power status TBD MCRIROS HCVS effluent radiation monitor I/2T48-N 152 MCRIROS 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-13-109. Notes: None OIP Phase 1 and Phase 2 Rev. 1 Page 26 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: HCVS Support Equipment Functions Determine venting capability support functions needed Ref: EA-13-1 09 Section 1.2.8, 1.2.9/ NEl 13-02 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 hours. 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 hours. 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 l/2T48-F082 vent valve. Severe Accident Venting Provide a general description of the Severe Accident Venting actions support functions. Identify methods and strategy( ies) utili~ed to achieve venting results. Ref: EA-13-109 Section 1.2.8, 1.2.9 I 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 hours, a set of dedicated HCVS batteries will be available to feed HCVS loads via a manual transfer switch. At 24 hours, power will be switched back to the normal configuration powered by FLEX generators evaluated for SA capability. Back-up nitrogen bottles will be installed in the Control Building to be available to tie-in supplemental pneumatic sources before the air accumulator tanks are depleted. Details Provide a brief description of Procedures I Gjidelines: Confirm that procedure/guidance exists or will be developed to support implementation. I OIP Phase 1 and Phase 2 Rev. 1 Page 27 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar~ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: HCVS Support Equipment Functions 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 hours. 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. EA- t 2-049 Modifications applicable to HCVS operation

  • Provide connection points and cabling at the control building wall and turbine building (SW Corner) to connect FLEX 600V AC diesel generators to the 600 V AC Bus C and Bus D to provide power to the battery chargers and critical AC components after 24 hours.

EA 109 Modification:

  • Provide piping and connection points at a suitable location in the control building to connect portable nitrogen bottles for motive force to HCVS components after 24 hours. 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- t 2-06 section t I 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 plallf 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-t 2-049 compliance) Pressure gauge on supplemental nitrogen bottles, to be staged with Nitrogen bottles. Notes: None OIP Phase 1 and Phase 2 Rev. 1 Page 28 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 2: Boundar)£ Conditions for Wet Well Vent Part 2 Boundary Conditions for WW Vent: HCVS 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 I NEI13-02 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 protected how the equipment will be 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 hours for the valve motive force. OIP Phase 1 and Phase 2 Rev. 1 Page 29 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3: Boundary Conditions for EA-13-1 09, Option 8.2 General: Licensees that use Option B. I of EA-13-109 (SA Capable DW Vent without SAWA) must develop their own OJP. This template does not provide guidance for that option. Licensees using Option 8.2 of EA-13-109 (SAWA and SAWM or 545°F SADW Vent (SADV) with SAWA) may use this template for their OJP submittal. Both SA WM and SADV require the use of SA WA and may not be done independently. The HCVS actions under Part 2 apply to all of the follo wing: This part is divided into the following sections: 3.1: Severe Accident Water Addition (SA WA)

3. l .A: Severe Accident Water Management (SA WM)
3. J.B: Severe Accident DW Vent (545 deg F)

Chart on Attachment 2./.C lists the plant-specific information to support SAWA and SAWM actions. Provide a sequence of events and identify any time constraint required for success including the basis for the time constraint. SAWA and SAWM or SADV Actions supporting SA conditions 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 walkthrough of deployment). Actions already identified under the HCVS part of this template need not be repeated here. The time to establish the water addition capability into the RPV or DW should be less than 8 hours from the onset of tlze los of all injection sources.

  • Electrical generators satisfying the requirements of EA-12-049 may be credited for powering components and instrumentation needed to establish a flow path.
  • Time Sensitive Actions (TSAs) for the purpose of SA WA are those actions needed to transport, connect and start portable equipment needed to provide SA WA flow or provide power to SA WA components in the flow path between the connection point and the RPV or drywell. Actions needed to establish power to SA WA instrumentation should also be included as TSAs.

Ref: NEI 13-02 Section 6.1.1.7.4.1, 1.1.4, 1.1.5 The operation of the HCVS using SAWA will be designed to minimize the reliance on operator actions in response to hazards listed in Part 1. Initial operator actions will be completed by plant personnel and will include the capability for remote-manual initiation from the MCR using control switches, at MCC/Busses in the Control Building and locally at the intake structure. In addition, HCVS operation may occur at the ROS on the 147'elevation in the Control Building. Timelines (see attachments 2 and 2.1.A for SAWA and SAWM) were developed to identify required operator response times and actions. The timelines are an expansion of Attachment 2 and begin either as core damage occurs (SAWA) or after initial SAWA injection is established and as flowrate is adjusted for option B.2 (SA WM). The timelines are appropriate for both in-vessel and ex-vessel core damage conditions. OIP Phase 1 and Phase 2 Rev. 1 Page 30 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundar~ Conditions for SAWA Table 3.1 - SAW A Manual Actions Primary Action Primary Location I Component Notes I. Establish HCVS capability in accordance with Part 2 of this

  • MCRor ROS guidance.
2. Connect SAW A pump I motive component to water source
  • River
3. Connect SAW A pump discharge to injection piping
  • Use installed piping
  • RHRSW at Intake
4. Power up SAW A (RHR/RHRSW)
  • RHR/RHRSW valves may be
  • Should be done as soon as valves with EA-12-049 (FLEX) operated from the main possible generator control room after re-establishing power to the MOVs using the FLEX diesel generator
5. Inject to RPV using SAWA pump (diesel)
  • gpm Initial SAWA injection rate is 500
6. Monitor SAWA indications
  • UsingPump 0

Skid mounted Flow 0 Valve Position

7. Use SA WM to maintain availability of the SAWV (Section
  • MCR and Intake
  • Monitor DW Pressure and Suppression Pool Level in MCR
3. 1.A)
  • Control SAWA at pump skid at intake (reduced to IOOGPM or less)

Discussion of timeline SAWA identified item HCVS operations are discussed under Phase I of EA 109 (Section 2 of this OIP).

  • 7.5 Hours - Establish electrical power and other EA-12-049 actions needed to support the strategies for EA 109, Phase 1 and Phase 2. Action being taken within the reactor building under EA-12-049 conditions after RPV level lowers to 2/3 core height must be evaluated for radiological conditions assuming permanent containment shielding remains intact. (HCVS-FAQ-12) All other actions required are assumed to be in-line with the FLEX timeline submitted in accordance with the EA-12-049 requirements.
  • Less than 8 Hours- Initiate SAWA flow to the RPV. Having the HCVS in service will assist in minimizing the peak DW pressure during the initial cooling conditions provided by SAWA.

I Severe Accident Operation I OIP Phase 1 and Phase 2 Rev. 1 Page 31 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundary Conditions for SAWA Determine operating requirements for SA WA , such as may be used in an ELAP scenario to mitigate core damage. Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3/ NEI13-02 Section 1.1.6, 1.1.4.4 It is anticipated that SAW A will be used in Severe Accident Events based on presumed failure of injection systems or presumed failure of injection systems in a timely manner. This does not preclude the use of the SAWA system to supplement or replace the EA-12-049 injection systems if desired. SAWA will consist of both portable and installed equipment. The motive force equipment needed to support the SAWA strategy shall be available prior to t=8 hours from the loss of injection (assumed at T=O). The SAW A flow path includes methods to minimize exposure of personnel to radioactive liquids I gases and potentially flammable conditions by inclusion of backflow prevention. The check valve is integral with the pump skid and will close and prevent leakage when the SAW A pump is secured. RHR LPCI injection mode has installed ECCS backflow prevention devices ( 112E II-F050NB) qualified for accident scenarios. Description of SAW A actions for first 24 hours: T<l hr:

  • No evaluation required for actions inside the reactor building for SAWA. Expected actions are:

o None T=l -7* hr:

  • Evaluation of core gap release impact to reactor building access for SAWA actions is required. It is assumed that reactor building access is limited due to the source term at this time unless otherwise noted.

Expected actions are: o None

  • Establish electrical power for SAWA systems and indications using EA-12-049.

o step 4 of table 3.1 above

  • The assumed times ofT= I hour to T=8 hours to establish the bounds of applicability of radiological evaluations have been reduced to T=l h to T=7 hours in order to provide sufficient margin to inform operator action feasibility evaluations and will be further informed by emergency response dose assessment activities during an actual event.

T<8hr:

  • Establish flow to the RPV using SAWA systems. Begin injection at a maximum rate, not to exceed 500 gpm.

o steps 2, 3, 5 and 6 of table 3.1 above T<8 -12 hr:

  • Continue injection for 4 hours after SAWA injection begins at initial SAWA rate.

T<l2 hrs:

  • Jroceed to SAWM actions (Part 3.l.A) o step 7 of table 3.1 above OIP Phase 1 and Phase 2 Rev. 1 Page 32 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundary Conditions for SAWA Greater Than 24 Hour Coping Detail Provide a general description of the SAWA actions for greater than 24 hours using portable and installed equipment including station modifications that are proposed. Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3/ NEI 13-02 Section 4.2.2.4.1 .3.1, 1.1.4, SAW A Operation is the same for the full period of sustained operation. SAWM flowrates will be directed to preserve the availability of the HCVS wetwell vent (see 3.1.A). Details: Details of Design Characteristic s/Performance Specifications SA WA shall be capable of providing a RPV or DW injection rate of 500 gpm within 8 hours of a loss of all RPV injection following an ELAP/Severe Accident. SA WA shall meet the design characteristics of the HCVS with the exception of the dedicated 24 hour power source. Hydrogen mitigation is not applicable to SA WA. Ref: EA-13-109 Attachment 2, Section B.2.1, B.2.2, B.2.3/ NEI 13-02 Section 1.1.4 Equipment Locations/Con trols/Instrume ntation The locations of the SAWA equipment and controls, as well as ingress and egress paths have been evaluated for the expected severe accident conditions (temperature, humidity, radiation) for the Sustained Operating period. Equipment has been evaluated to remain operational throughout the Sustained Operating period. Personnel exposure and temperature I humidity conditions for operation of SAWA equipment will not exceed the limits for ERO dose and plant safety guidelines for temperature and humidity. The flow path will be from the FLEX suction in the Altamaha river through the FLEX pumps with 4 outlets with individual flow indicators. One indicator will be dedicated to the unit in a Severe Accident, and the flow will be monitored that is pro ided to the RHR service water FLEX header. The monitored water flow rate will pass through the RHRSW piping to the Reactor Building where it will connect with the RHR system by opening MOV s from the MCR that interconnect the systems. The flow will then be directed into the RPV via the LPCI injection valves. Cross flow into other portions of the RHR system will be isolated by ensuring closure of the MOV s from the MCR. DW pressure and Suppression Pool level will be monitored and flow rate will be adjusted by use of the FLEX pump control valve at the Intake Structure. Communication will be established between the MCR and the FLEX pump location. MOV s will be powered from the FLEX diesel generators connected as described in the EA-12-049 compliance documents. The MOVs will be operated in series (not parallel) to limit the potential for overloading the FLEX DGs. The FLEX DGs are located near the Control Building which is significantly away from the discharge of the HCVS at the Main Meteorological Stack. Refueling of the FLEX DG will be accomplished from the EDG fuel oil tanks as described in the EA-12-049 compliance documents. The Intake Structure is a significant distance from the discharge of the HCVS at the Main Meteorological Stack. (see mechanical and electrical sketches in attachments, plant layout sketches in the ass~mptions part and a list of actions elsewhere in this part) I Evaluations for projected SA conditions (radiation I tem_IJ_erature) indicate that _personnel can complete the initial and OIP Phase 1 and Phase 2 Rev. 1 Page 33 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundar~ Conditions for SAWA support activities without exceeding the ERO-allowable dose for equipment operation or site safety standards. (reference HCVS-WP-02 ) Electrical equipment and instrumentation will be powered from the existing station batteries, and from AC distribution systems that are powered from the EA-12-049 generator(s). The battery chargers are also powered from the EA-12-049} generator(s) to maintain the battery capacities during the Sustained Operating period. Parameter Instrument Location Power Source I Notes DW Pressure 112T48-R608/R609 MCR Station batteries via EA-12-049 generator Torus Level l/2T48-R607A/B MCR Station batteries via EA-12-049 generator SAWAFiow FLEX Pump Flow FLEX Pump Skid SAWA pump (skid indicator mounted device) SAWA pump power On-Board Generator I/2T48-R607 AlB EA-12-049 generator RHR and RHRSW Valve MCRPanels MCR and Control 1R24-S012/S018B controls Building (2R24-SO II/SO 18A) EA-12-049 generator The instrumentation and equipment being used for SAWA and supporting equipment has been evaluated to perform for the Sustained Operating period under the expected radiological and temperature conditions. Equipment Protection Any SAWA component and connections external to protected buildings have been protected against the screened-in hazards of EA-12-049 for the station via a below grade valve pit connecting to piping in the intake structure and the Reactor Building. Portable equipment used for SAWA implementation will meet the protection requirements for storage in accordance with the criteria in NEI 12-06 Revision 0. Provide a brief description of Procedures I Guidelines: Confirm that procedure/guidance exists or will be developed to support implementation. Ref: EA-13-109 Attachment 2, Section A.3.1, B.2.3/ NEI 13-02 Section 1.3, 6.1.2

  • Hook up FLEX pump to intake manifold per FSG
  • Hook-up and start FLEX DG to repower 1R24-S012(2R24-S011) and 1R24-SOI8B(2R24-S018A)
  • Open 1E11-F073B(2E11-F073A) and 1E11-F075B(2E11 -F075A) using MCR Switches to cross tie RHR with RHRSW
  • Verify using MCR switches that 1/2E11-F003A! F016A, F028A, F048A and 1/2E11-F068AIB are closed to I isolate RHR SDC modes OIP Phase 1 and Phase 2 Rev. 1 Page 34 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1 : Boundar~ Conditions for SAWA

  • Open I EII-F015B(2EII-F OI5A) and I EII-FOI7B(2EIJ-F 017A) using MCR Switches for RHR LPCJ injection pathway
  • Start FLEX pump via on-board generator
  • Adjust flow rate using skid mounted flow indicator and isolation valve Identify modifications:

List modifications and describe how they support the SA WA Actions. Ref: EA-13-109 Attachment 2, Section B.2.2, I NEI 13-02 Section 4.2.4.4, 7.2.1.8, Appendix I None Component Qualifications: State the qualification used for equipment supporting SA WA Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3/ NEI 13-02 Section I.1.6 Permanently installed plant equipment shall meet the same qualifications as described in Part 2 of this OIP. Temporary/Portable equipment shall be qualified and stored to the same requirements as FLEX equipment as specified in NEI 12-06. SAW A components are not required to meet NEI 13-02, Table 2-1 design conditions. Notes: None OIP Phase 1 and Phase 2 Rev. 1 Page 35 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.A: Boundary Conditions for SAWA/SAWM Time periods for the maintaining SAWM actions such that the WW vent SA WM Actions supporting SA conditions 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 walkthrough of deployment). Actions already identified under the HCVS part of this template need not be repeated here. There are three time periods for the maintaining SA WM actions such that the WW vent remains available to remo ve decay heat from the containment:

  • SA WM can be maintained for> 7 days without the need for a cbywell vent to maintain pressure below PCPL or containment design pressure, whichever is lower.

o Under this approach, no detail concerning plant modifications or procedures is necessmy with respect to how alternate containment heat removal will be provided.

  • SA WM can be maintained for at least 72 hours, but less than 7 days before containment pressure reaches PCPL or design pressure, whichever is lower.

o Under this approach, afunctional description is required of how alternate containment heat removal might be established before containment pressure reaches PCPL or design pressure whichever is lower. Under this approach, physical plant modifications and detailed procedures are not necessary, but written descriptions of possible approaches for achieving alternate containment heat removal and pressure control will be provided.

  • SA WM can be mabztainedfor <72 hours SAWM strategy can be implemented but for less than 72 hours before containment pressure reaches PCPL or design pressure whichever is lower.

o Under this approach, afunctional description is required of how alternate containment heat removal might be established before containment pressure reaches PCPL or design pressure whichever is lower. Under this approach, physical plant modifications and detailed procedures are required to be implemented to insure achieving alternate containment heat removal and pressure control will be provided for the sustained operating period. Ref: NEI 13-02 Appendix C.7 SA WM can be maintained for> 7 days without the need for a drywell vent to maintain pressure below PCPL. Basis for SA WM time frame SA WM can be maintained > 7 days: Plant Hatch is bounded by the evaluations performed in BWROG TP-15-0 11 and representative of the reference plant in NEI 13-02 figures C-2 through C-6. Instrumentation relied upon for SAWM operations is DW pressure and Suppression Pool level. Both of which are initially powered by station batteries and then by the FLEX (EA-12-049) generator which is placed in-service prior to core breach. The DG will provide power throughout the Sustained Operation period (7 days) . (C.7.1.4.2) DW Temperature monitoring is not a requirement for compliance with Phase 2 of the order, but some knowledge of temperature characteristics provides information for the operation staff to evaluate plant conditions under a severe accident and provide confirmation to adjust SAWA flow rates (C.8.3.1) Suppression Pool level indication is !maintained throughout the Sustained Operation period, so th~ HCVS remains in-service. The time to reach the level at which the WW vent must be secured is>?days using SAWM flowrates (C.6.3, C.7.1.4.3) OIP Phase 1 and Phase 2 Rev. 1 Page 36 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.A: Boundar~ Conditions for SAWA/SAWM Procedures will be developed that control the Suppression Pool level in the indicating range, while ensuring the DW pressure indicate the core is being cooled, whether in-vessel or ex-vessel. Procedures will dictate conditions during which SAWM flowrate should be adjusted (up or down) using Suppression Pool level and DW pressure as controlling parameters to remove the decay heat from the containment. (this is similar to the guidance currently provided in the BWROG SAMGs) (C.7.1.4.3) Attachment 2.1.A shows the timeline of events for SAWA I SA WM. (C.7.1.4.4) T able 3.l.B - SAWM Manual Actions Primary Action Primary Location I Notes Component I. Lower SAWA injection rate to control Intake Structure

  • Control to maintain containment and Suppression Pool parameters to ensure Suppression Pool level SAWV remains operational.

and decay heat removal

  • 100 gpm minimum capability is maintained for greater than 7 days
2. Control to SAWM flowrate for containment Intake Structure and MCR
  • SA WM Flowrates will be monitored using the following instrumentation control I decay heat 0 FLEX Pump Flow removal 0 Suppression Pool level DW pressure 0

SAWM flowrates will be controlled using the manual flow control valve at the FLEX pump

3. Establish alternate source of decay heat removal Yard
                                                                    *  >7days
4. Secure SAWA I SAWM Intake Structure
  • When reliable alternate containment decay heat removal is established.

SAWM Time Sensitive Actions Time Sensitive SAWM Actions: 12 Hours- Initiate actions to maintain the Wetwell vent (SAWV) capability by lowering injection rate, while maintaining the cooling of the core debris (SA WM). Monitor SAWM critical parameters while ensuring the SAWV remains available. SAWM Severe Accident Operation OIP Phase 1 and Phase 2 Rev. 1 Page 37 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.A: Boundar~ Conditions for SAWA/SAWM Determine operating requirements for SAWM, such as may be used in an ELAP scenario to mitigate core damage. Ref: EA-13-109 Attachment 2, Section 8.2.2, 8.2.31 NEI 13-02 Appendix C It is anticipated that SA WM will only be used in Severe Accident Events based on presumed failure of plant injection systems as directed by the plant SAMGs. Refer to Attachment 2.1.0 for SAWM SAMG language additions. First 24 Hour Coping Detail Provide a general description of the SA WM actions forfirst 24 hours using installed equipment including station modifications that are proposed. Given the initial conditions for EA-13-109: BDBEE occurs with ELAP Failure of all injection systems, including steam-powered injection systems Ref: EA-13-109 Section 1.2.6, Attachment 2, Section 8.2.2, 8.2.3 I NEI 13-02 2.5, 4.2.2, Appendix C, Section C.7 SAWA will be established as described above. SAWM will use the installed instrumentation to monitor and adjust the flow from SAWA to control the pump discharge to deliver flowrates applicable to the SAWM strategy. Once the SAWA initial flow rate has been established for 4 hours, the flow will be reduced while monitoring DW pressure and Suppression Pool level. SA WM flowrate will be lowered to maintain containment parameters and preserve the WW vent path. SAWA will be capable of injection for the period of Sustained Operation. Greater Than 24 Hour Coping Detail Provide a general description of the SAWM actions for greater than 24 hours using portable and installed equipment including station modifications that are proposed. Ref: EA-13-109 Section 1.2.4, 1.2.8, Attachment 2, Section 8.2.2, 8.2.31 NEI 13-02 Section 4.2.2, Appendix C, Section C.7 SAWM can be maintained> 7 da;rs: The SAWM flow strategy will be the same as the first 24 hours until 'alternate reliable containment heat removal and pressure control' is reestablished. SA WM flow strategy uses the SAWA flow path. No additional modifications are being made for SA WM. Details: Details of Design Characteristic s/Performance Specifications Ref: EA-13-109 Attachment 2, Section 8.2.2, 8.2.3 I NEI 13-02 Section Appendix C I I OIP Phase 1 and Phase 2 Rev. 1 Page 38 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.A: Boundary Conditions for SAWNSAWM SA WM shall be capable of monitoring the containment parameters (DW pressure and Suppression Pool Level) to provide guidance on when injection rates shall be reduced, until alternate containment decay heat/pressure control is established. SAW A will be capable of injection for the period of Sustained Operation. Equipment Locations/Controls/Instrumentation Describe location for SAWM monitoring and control. Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3 I NEI 13-02 Appendix C, Section C.8, Appendix I The SAWM control location is the same as the SAW A control location. Local indication of SAWM flowrate is provided at the pump skid by installed flow instrument qualified to operate under the expected environmental conditions. Injection flowrate is controlled by FLEX manual valve located on the FLEX pump at the Intake Structure Suppression Pool level and DW pressure are read in the control room using indicators powered by the FLEX DG installed under EA- 12-049. These indications are used to control SAWM flowrate to the RPV. Key Parameters: List instrumentation credited for the SA WM Actions. Parameters used for SA WM are:

  • Drywell Pressure*
  • Suppression Pool Level*
  • SAWM Flowrate The Containment Pressure and Suppression Pool Level instruments are qualified to RG 1.97 and are the same as listed in Part 2 of this OIP. The SAWM flow instrumentation is qualified for the expected environmental conditions when needed which is extreme temperatures Notes:

None OIP Phase 1 and Phase 2 Rev. 1 Page 39 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.8: Boundary Conditions for SAWA/SADV Applicabil ity of WW Design C onside r a tions All of Part 2 of this OIP applies to the SADV, with the exception that the temperature qualification for SADV components, and interfacing WW Vent components, shall be rated for 545 Deg F. Table 3.1.C- SADV Man ual Actions N/A Timeline for SADV Describe timeline for SADV actions from the time the WW vent is no longer operational N/A 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 Attachmen t 2, Section B.2.1, B.2.2, B.2.3 I NEI 13-02 Appendix J, HCVS-FAQ -01, HCVS-FAQ - 02, HCVS-FAQ -03, HCVS-FAQ -04 N/A First 24 Hour Coping Detail Provide a general description of the SADV actionsforf irst 24 hours using installed equipment including station modifications that are proposed. Ref: EA-13-109 Attachmen t 2, Section B.1.1, B.1.2 I NEI 13-02 Section 4.2, Appendix I N/A Greater Than 24 Hour Coping Detail Provide a general description of the SADV actions for greater than 24 hours using portable and installed equipment including station modifications that are proposed. Ref: EA-i3-109 Attachmen t 2, Section B.1.1, B.1.2 I NEI 13-02 Secdon 2.5, 4.2.2, Appendix I OIP Phase 1 and Phase 2 Rev. 1 Page 40 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 3.1.8: Boundar~ Conditions for SAWA/SADV N/A Details: Provide a brief description of Procedures I Guidelines: Confirm that procedure/guidance exists or will be develop ed to support implementation. Ref: EA-13-109 Attachment 2, Section 8.1.1, 8.1.2/ NEI 13-02 Section 6.1.2 N/A Identify modifications: List modifications and describe how they support the SADV Actions. N/A Key Venting Parameters: List instrumentation credited for the SADV Actions. N/A OIP Phase 1 and Phase 2 Rev. 1 Page 41 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 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 1.2.10, 3.1, 3.2/ NEI 13-02 Sections 5, 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 analyzed for radiation and temperature to ensure they are accessible 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 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/SA WA functionality are applicable in Modes I, 2 and 3.

  • If for up to 90 consecutive days, the primary or alternate means of HCVS/SA W A operation are non-functional, no compensatory actions are necessary.
  • If for up to 30 days, the primary and alternate means of HCVS/SA W A operation are nonfunctional, no compensatory actions are necessary.
  • If the out of service times exceed 30 or 90 days as described above, the following actions will be performed through the sites corrective action program:

o The cause(s) of the non-functionali tjy I o The actions to be taken and the schedule for restoring the system to functional status and prevent recurrence OIP Phase 1 and Phase 2 Rev. 1 Page 42 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 4: Programmatic Controls 1 Training! Drills and Maintenance 0 Initiate action to implement appropriate compensatory actions, and 0 Restore full HCVS functionality at the earliest opportunity not to exceed one full operating cycle.: [OPEN ITEM 11: Determine the control document for HCVS out of service time criteria] Describe training plan List training plans for ajj"ected organizations or describe the plan for training development Ref: EA-13-109 Section 3.2/ NEI 13-02 Section 6.1.3 Personnel expected to perform direct execution of the HCVS/SA W A/SA WM actions 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/ SAWA/SA WM actions, systems or strategies. Training content and frequency will be established using the Systematic Approach to Training (SAT) process. Identify how the drills and exercise parameters will be met. Alignment with NEI I 3-06 and 14-01 as codified in NITF Recommendation 8 and 9 rulemaking The Licensee should demonstrate use of the HCVS/SAWAISAWM system in drills, tabletops, or exercises as follows:

  • Hardened containment vellf 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//oss 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 ELAPI/oss of UHS with core damage. System use is for containment heat removal AND containment pressure control with potentia/for combustible gases (Demonstration may be in conjunction with SAG change).
  • Operation for sustained period with SAWA and SAWM to provide decay heat removal and containment pressure control.

Ref: EA-13-109 Section 3.1/ NEI 13-02 Section 6.1.3 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: Describe the elements of the maintenance plan

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

0 Periodic testing andfrequenc.) should be determined based on equipment type, expected usd and manufacturer's recommendations (further details are provided in Part 6 of this document). OIP Phase 1 and Phase 2 Rev. 1 Page 43 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 4: Programmatic Controls ! Training , Drills and Maintenance 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 documellted 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/SA WA permanent installed equipment should be maintained in a manner that is consistent with assuring that it petforms its fun ction when required.

o HCVS/SA WA permanently installed equipment should be subject to maimenance and testing guidance provided to verify proper function.

  • HCVS/SA WA 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/ 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/SAW A/SAWM 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 and SAW A to ensure reliable operation of the system. Table 4-1: Testing and Inspection Requirements Description Frequency Cycle the HCVS and installed SAWA valves 1 and the Once per everi operating cycle interfacing system boundary valves not used to maintain containment integrity during Mode 1, 2 and 3. For HCVS valves, this test may be performed concurrently with the control logic test described below. Cycle the HCVS and installed SAWA check valves not Once per every other4 operating cycle used to maintain containment integrity during unit operations3 Perform visual inspections and a walk down of HCVS Once per every other4 operating cycle and installed SAWA components Functionally test the HCVS radiation monitors. Once per operating cycle OIP Phase 1 and Phase 2 Rev. 1 Page 44 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 4: Programmatic Controls. Training, Drills and Maintenance Leak test the HCVS. I. 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 conducting Once per every other operating cycle an open/close test of the HCVS control function from its control location and ensuring that all HCVS vent path and interfacing system boundary valves 5 move to their proper (intended) positions.

1 Not required for HCVS and SAWA check valves. 2 After two consecutive successful performances, the test frequency may be reduced to a maximum of once per every other operating cycle. 3 Not required if integrity of check function (open and closed) is demonstrated by other plant testing requirements. 4 After two consecutive successful performances, the test frequency may be reduced by one operating cycle to a maximum of once per every fourth operating cycle. 5 Interfacing system boundary valves that are normally closed and fail closed under ELAP conditions (loss of power and/or air) do not require control function testing under this section. Performing existing plant design basis function testing or system operation that reposition the valve(s) to the HCVS required position will meet this requirement without the need for additional testing. Notes: OIP Phase 1 and Phase 2 Rev. 1 Page 45 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 5: Milestone Schedule Provide a milestone schedule This schedule should include:

  • Modificatio ns timeline
  • Procedure guidance developme nt 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 subject to change. Updates will be provided in the periodic (six month) status reports.

Ref: EA-13-109 Section 0.1, 0.3/ NEI13-02 Section 7.2.1 The following milestone schedules are 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. Phase 1 Milestone Schedule: Phase 1 Milestone Schedule: Milestone Target Activity Comments Completion Status {.Include date changes in Date this columnl Hold preliminary/conceptual design meeting Jun, 2014 Complete Submit Overall Integrated Implementation Plan Jun 2014 Complete Submit 6 Month Status Report Dec.2014 Complete Submit 6 Month Status Report Jun. 2015 Complete Submit 6 Month Status Report Dec. 2015 Complete Simultaneous with Phase 2 OIP U2 Design Engineering On-site/Complete May 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 

             .L U2 Implementation Outage                                        Feb,2017 Procedure Changes Active                                        Mar, 2017 OIP Phase 1 and Phase 2 Rev. 1                 Page 46 of66                           December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 5: Milestone Schedule U2 Walk Through Demonstration/Functional Test Mar, 2017 U 1 Design Engineering On-site/Complete Mar, 2017 Submit 6 Month Status Report Jun.2017 Submit 6 Month Status Report Dec. 2017 U 1 Implementation Outage Feb,2018 U1 Walk Through Demonstration/Functional Test Mar, 2018 Submit Completion Report May, 2018 Phase 2 Milestone Schedule: Phase 2 Milestone Schedule Milestone Target Activity Comments Completion Status {.Include date changes in Date this columnl Submit Overall Integrated Implementation Plan Dec 2015 Complete Hold preliminary/conceptual design meeting Apr2016 Expect to be engineering justification not modifications Submit 6 Month Status Report June 2016 Submit 6 Month Status Report Dec 2016 U1 Design Engineering On-site/Complete Feb 2017 Expect to be engineering justification not modifications Submit 6 Month Status Report June 2017 Operations Procedure Changes Developed Sep 2017 SAMG Revision Site Specific Maintenance Procedure Developed Dec 2017 Expect to be N/ A Training Complete Dec 2017 Submit 6 Month Status Report Dec 201 7 U2 Design Engineering On-site/Complete Feb 2018 Expect to be engineering justification not modifications U1 Implementation Outage Mar2018 Procedure Changes Active Mar 2018 U1 IWalk Through Demonstration/Functional Test Mar 2018 Submit 6 Month Status Report June 2018 OIP Phase 1 and Phase 2 Rev. 1 Page 47 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Part 5: Milestone Schedule Submit 6 Month Status Report Dec 2018 U2 Implementation Outage Mar 2019 U2 Walk Through Demonstration/Functional Test Mar 2019 Submit Completion Report May 2019 Notes: OIP Phase 1 and Phase 2 Rev. 1 Page 48 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 1: HCVS/SAWAISADV Portable Egui~ment BDBEE Severe Performance Maintenance I PM requirements List portable equipment Venting Accident Criteria 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 (and associated equipment) X X TBD Per Response to EA-12-049 SAWA Pump (and associated equipment) X X TBD Per Response to EA-13-1 09 

                                       -~-
                                             - - - - '--~-~--
                                                                                             /

OIP Phase 1 and Phase 2 Rev. 1 Page 49 of66 December 6, 2015

Enclosure to NL-15-212 1 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2A: Sequence of Events Timeline- HCVS t ... 5 m t= 1 hr t=0s RCIC E LAP SSO stans Ded.ved Case 1 FLEX Successf: t.,7 hrs t.,1Dhrs t., 18hrs Containment Venting ~----------iRef: HNP FLEX 0 Blow Antic:ipa1ory Ponable {~31Dry ven11ng ruptUJ"e diSC Venting generaliOr in nat represented in No Injection place for Fl.EX No Injection SECY-12-01 57) and HCVS loads I 

                                                                                                        *I I

I Level at TAF

  • Case 2
  • J RC IC LateFailu re tQO 23 hrs t"" 24 hrs t ... 34 h rs Ref: S ECY-12-0157 Containment Venting t,..11hrs I

I (based on preventing Begin monitori~ at MCR or ROP I I t ... 24 hrs exceeding PCPL) HCVS pneumatic and batte ry stah.ls. I Repfenish ment of HCVS No replenishmen1 expected to be power and pneumatic required before t = 24 hours I I I supplies I I t ... 12hrs I I Trar!Sfer to I I HCVS Battery I Case 3 RC IC Ea:rly Failu re t""' h r t!>r81Vs tR>11h.rs Ref: SOARCA t ... 24 hrs t"' 12 hrs l_iAWA Injection BeQins I Legend Refe rences: 

    -         ~ OCIII'e cooling maintained                                                             C3Se 1: HN P FLEX 0\llerall l n:egrated Pfan lnjeotJon Lost                                                                           C3Se 2: S ECY 0157 - ML12344A030
    -         lnaeased shinct and leakage of radionuclides pril'n3dy &an \Y                            C3Se 3 : SOARCA - M L 131 50A053
    -         HCVS Post Core Dalnag@ Dose Evaluation Required HCVS Ti~ evaluation .-.auired
                                                                                                                                                            ~-Not to5care )

OlP Phase 1 and Phase 2 Rev. 1 Page 50 of 66 Decem ber 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2.1.A: Sequence of Events Timeli ne- SAWA I SAWM Sustained Operation period T=168 hr ( T= 8 hr 1 T=72 hr --, SAWA Injection Flow beginsT<soo gpm) Control SAWM flow rate using drywell pressure and suppression pool level indications OIP Phase 1 and Phase 2 Rev. 1 Page 51 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2.1.8: Sequence of Events Timeline - SADV N/A OIP Phase 1 and Phase 2 Rev. 1 Page 52 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2.1.C: SAWA I SAWM Plant-Specific Datum SAWV El. 117.1 {331" ) Spillover height 18 inches (EL. 116 Additional freeboard height= 31" 't:~- ------~~E~L- .~ 11:-::6:-:-{3~1= 8"' ) Drywell floor El. 114.5 (300"from Bottom of Torus) level instrument span = 150" to 154" (>12.5' ) Normal Torus (n::vo::: 11

  • l y y
  • El. 101.7 to 102 (146" to
  • Torus water volume at elevations
                                                                                                                             =

o Elevation 150" 679,319 gallons o Elevation 300" = 1,484,580 gallons Bottom of Toru s El. 89.5 {0" ) ---------==~---~

  • Estimated of the rate of level change in the suppression pool for SAWA flow rates*

o 500 gpm = 6 inches per hour average o 100 gpm = 1 inch per hour average 

                                                                                            *Does not consider mass loss rate of steam leaving containment through wetwell vent path OIP Phase 1 and Phase 2 Rev. 1                               Page 53 of66                                         December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 2.1.0: SAWM SAMG Approved Language The following general cautions, priorities and methods will be evaluated for plant specific applicability and incorporated as appropriate into the plant specific SAMGs using administrative procedures for EPGISAG change control process and implementation. SAMGs are symptom based guidelines and therefore address a wide variety of possible plant conditions and capabilities while these changes are intended to accommodate those specific conditions assumed in Order EA-13-109. The changes will be made in a way that maintains the use of SAMGs in a symptom based mode while at the same time addressing those conditions that may exist under extended loss of AC power (El.AP) conditions with significant core damage including ex-vessel core debris. Actual Approved Language that will be incorporate d into site SAMG* Cautions:

  • Addressing the possible plant response associated with adding water to hot core debris and the resulting pressurization of the primary containment by rapid steam generation.
  • Addressing the plant impact that raising suppression pool water level above the elevation of the suppression chamber vent opening elevation will flood the suppression chamber vent path.

Priorities: With significant core damage and RPV breach, SAMGs prioritize the preservation of primary containment integrity while limiting radioactivity releases as follows : 

      .!.__ Core debris in the primary containment is stabilized by water addition (SAWA)
  • Primary containment pressure is controlled below the Primary Containment Pressure Limit (Wetwell venting)
  • Water addition is managed to preserve the Mark IIII suppression chamber vent paths, thereby retaining the benefits of suppression pool scrubbing and minimizing the likelihood of radioactivity and hydrogen release into the secondary containment (SAWM)

Methods: Identify systems and capabilities to add water to the RPV or drywell, with the following generic guidance:

  • Use controlled injection if possible.
  • Inject into the RPV if possible.

Maintain injection from external sources of water as low as possible to preserve suppression chamber vent capability.

  • Actual language may vary by acceptable site procedure standards, but intent and structure should follow this guidance.

OIP Phase 1 and Phase 2 Rev. 1 Page 54 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 3: Conceptual Sketches (Conceptual sketches, as necessary to indicate equipment which is installed or equipment hookups necessary for the HCVS Actions) Sketch 1: Electrical Layout of System (preliminary)

  • Instrumentation Process Flow
  • Electrical Connections Sketch 2: P&ID Layout of WW Vent (preliminary)
  • Piping routing for vent path - WW Vent
  • Demarcate the valves (in the vent piping) between the currently existing and new ones
  • WW Vent Instrumentation Process Flow Diagram
  • Egress and Ingress Pathways to ROS, Battery Transfer Switch, DG Connections and Deployment location
  • Site layout sketch to show location/routing of WW vent piping and associated components. This should include relative locations both horizontally and vertically Sketch 3: P &ID Layout of SAWA (preliminary)
  • Piping routing for SAWA path
  • SAWA instrumentation process paths
  • SAWA connections
  • Include a piping and instrumentation diagram of the vent system. Demarcate the valves (in the vent piping) between the currently existing and new ones.
  • Ingress and egress paths to and from control locations and manual action locations
  • Site layout sketch to show locations of piping and associated components. This should include relative locations both horizontally and vertically OIP Phase 1 and Phase 2 Rev. 1 Page 55 of66 Decem ber 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan ES: Dll' I PQ~"!FIL_Q.!STRIRUTIQN DIV ' NorT.O!ly .. ,,.... ..._-y ITI'i" ~ ~ tZ~/t50V DC sWCR U ZS/2:!0V DC SICR ZB HATCit t'NIT 2 

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Sketch 1: Electrical Layout of System (Unit 2, Unit 1 similar) OIP Phase 1 and Phase 2 Rev. 1 Page 56 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan l 4CCUII~LA~OR ~~~~ r-J:::>-1 _n 

                                                          >~,Bo~;u" L ACCUMULATOQ TAMS/                                                                                          .ANKS/

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Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Sketch 3: P&ID Layout of SA WA (prelimillary) II I -~.. UNfT 1 DCV I IIHRSW L r -----LIXIII'Y I Jl2. r~ 

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OIP Phase 1 and Phase 2 Rev. 1 Page 58 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System {HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 4: Failure Evaluation Table Table 4A: Wet Well HCVS Failure Evaluation Table Failure with Alternate Action Functional Failure Impact on Mode Failure Cause Alternate Action Containment Venting? Failure of Vent to Open Valves fail to open/close due to No action needed, power is already tied into station No on Demand Joss of normal AC power service battery via inverter for minimum 12 hours Failure of Vent to Open Valves fail to open/close due to Connect dedicated batteries to inverter via transfer No on Demand loss of alternate AC power (long switch for minimum 12 hours term) Failure of Vent to Open Val ves fail to open/close due to Recharge station service batteries with FLEX provided No on Demand complete loss of batteries (long generators, considering severe accident conditions term) Failure of Vent to Open Val ves fail to open/close due to No action needed, air can be supplied by accumulator No on Demand loss of normal pneumatic air tanks, which is sufficient for at least 8 cycles of F082 supply valve over first 24 hours. Failure of Vent to Open Valves fail to open/close due to Tie-in nitrogen cylinders to air system supporting No on Demand loss of alternate pneumatic air HCVS valves, replace bottles as needed. supply (long term) Failure of Vent to Open Valves fail to open/close due to Heroic action needed Yes on Demand SOV failure OIP Phase 1 and Phase 2 Rev. 1 Page 59 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 5: References I. Generic Letter 89-16, Installation of a Hardened Wetwell Vent, dated September I, 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-13-109, 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-20 12-02, Compliance with Order EA-12-050, Reliable Hardened Containment Vents, dated August 29, 2012
8. JLD-ISG-2013-02, Compliance with Order EA-13-109, 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-20 12-02: Compliance with Order EA-12-050, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents, ADAMS Accession No. ML12229A477, dated August 29, 2012 I0. NEI 12-06, Diverse and Flexible Coping Strategie * (FLEX) Implementation Guide, Revision 0, dated August 2012 II. NEI 13-02, Industry Guidance for Compliance with Order EA-13-1 09, Revision I, Dated Apri12015
12. NEI 13-06, Enhancements to Emergency Response Capabilities for Beyond Design Basis Accidents and Events, Revision 0, dated March 2014
13. NEI 14-0 I, 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 Mechanism.
17. NEI HCVS-FAQ-04, HCVS Release Point
18. NEI HCVS-FAQ-05, HCVS Control and 'Boundary Valves' I 9. 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 I

OIP Phase 1 and Phase 2 Rev. 1 Page 60 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan

23. NEI White Paper HCVS-WP-0 I, HCVS Dedicated Power and Motive Force
24. NEI White Paper HCVS-WP-02, HCVS Cyclic Operations Approach
25. NEI White Paper HCVS-WP-03, Hydrogen/CO Control Measures
26. NEI White Paper HCVS-WP-04, Missile Evaluation for HCVS Components 30 Feet Above Grade
27. IEEE Standard 344-2004, IEEE Recommended Practice for Seismic Qualification of Class IE Equipment for Nuclear Power Generating Stations,
28. Edwin I. Hatch EA-12-049 (FLEX) Overall Integrated Implementation Plan, Rev 0, February 20 13
29. Edwin I. Hatch EA-12-050 (HCVS) Overall Integrated Implementation Plan, Rev 0, February 20 13
30. Edwin I. Hatch EA-12-051 (SFP Ll) Overall Integrated Implementation Plan, Rev 0, February 20 13
31. Edwin I. Hatch Procedure 31EO-EOP-IOI-I, Emergency Containment Venting (Unit I)
32. Edwin I. Hatch Procedure 31EO-EOP-IOI-2, Emergency Containment Venting (Unit 2)
33. Edwin I. Hatch Procedure 31EO-EOP-104-I, Primary Containment Venting for H2 and 02 Control (U I)
34. Edwin I. Hatch Procedure 31 EO-EOP-104-2, Primary Containment Venting for H2 and 02 Control (U2)
35. Edwin I. Hatch Procedure 31 EO-EOP-0 12-1, U I PC Flowchart
36. Edwin I. Hatch Procedure 31EO-EOP-OI2-2, U2 PC Flowchart
37. Edwin I. Hatch Procedure 31EO-PCG-OOI-I, Ul PC-G Flowchart
38. Edwin I. Hatch Procedure 31EO-PCG-OOI-2, U2 PC-G Flowchart
39. Edwin I. Hatch Procedure 3IEO-SAG-00l-l, Ul SAG-01 Flowchart
40. Edwin I. Hatch Procedure 31EO-SAG-OOI-2, U2 SAG-01 Flowchart 4I. Edwin I. Hatch Procedure 3I EO-SAG-002-1, U I SAG-02 Flowchart
42. Edwin I. Hatch Procedure 3IEO-SAG-002-2, U2 SAG-02 Flowchart
43. Edwin I. Hatch Procedure 31 EO-TSG-00 l-0, Technical Support Guidelines
44. Edwin I. Hatch Procedure 3IEO-TSG-002-0, Technical Support Appendix J
45. Southern Nuclear Procedure NMP-EP-403, Figure I, EMG/EDMG Flowchart
46. Consideration of Additional Requirements for Containment Venting Systems for Boiling Water Reactors with Mark I and Mark II Containments, SECY-I2-0l57, MLI2344A030
47. NUREG/CR-7110, VI, Rl, State-of-the-Art Reactor Consequence Analyses (SOARCA)

Project: Peach Bottom Integrated Analysis, ML I3I50A053 OIP Phase 1 and Phase 2 Rev. 1 Page 61 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan

48. JLD-ISG-20 15-0 I, Compliance with Phase 2 of Order EA-13-1 09, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions, dated March 2015
49. NEI FAQ HCVS-10, Severe Accident Multiple Unit Response
50. NEI FAQ HCVS-11, Plant Response During a Severe Accident
51. NEI FAQ HCVS-12, Radiological Evaluations on Plant Actions Prior to HCVS Initial Use
52. NEI FAQ HCVS-13, Severe Accident Venting Actions Validation
53. NRC Endorsement of "Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Template, " Revision I, dated September 22, 2015, and Frequently Asked Questions (FAQs) 10, II, 12, and 13 (ADAMS Accession No. MLI5273AI41), dated October 8, 2015 OIP Phase 1 and Phase 2 Rev. 1 Page 62 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 6: Changes/Updates to this Overall Integrated Implementation Plan This Overall Integrated Plan has been updated in format and content to encompass both Phase 1 and Phase 2 of Order EA-13-1 09. Any significant changes to this plan will be communicated to the NRC staff in the 6 Month Status Reports OIP Phase 1 and Phase 2 Rev. 1 Page 63 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan Attachment 7: List of Overall Integrated Plan Open Items OIP Open Action Comment Item 1 Determine location of Dedicated HCVS Battery transfer Audit item per ISE switch 2 Determine location of back-up nitrogen bottles Audit item per ISE 3 Evaluate location of Portable DG for accessibility under Audit item per ISE Severe Accident HCVS use 4 Confirm suppression pool heat capacity Audit item per ISE 5 Determine location of HCVS Remote Operating Station Audit item per ISE (ROS) 6 State which approach or combination of approaches Plant Audit item per ISE 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 NEt Audit item per ISE HCVS-FAQ-05 8 Identify qualification method used for HCVS instruments Audit item per ISE 9 Evaluate HCVS monitoring location of Portable DG for Audit item per ISE accessibility, habitability, staffing sufficiency, and communication capability with Vent under Severe Accident HCVS 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 Audit item per ISE criteria OIP Phase 1 and Phase 2 Rev. 1 Page 64 of66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan ISE Action (OIP section reference) Open Items

1. Make available for NRC staff audit the location of the ROS's. OIP Item 5 (Section 3.2.1, Section 3.2.2.4, Section 3.2.2.5, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.2, Section 3.2.6)
2. Make available for NRC staff audit the location of the OIP Item 1 dedicated HCVS battery transfer switch. (Section 3.2.1, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.2, Section 3.2.6)
3. Make available for NRC staff audit documentation of the OIP Item 2 HCVS nitrogen pneumatic system design including sizing and location. (Section 3.2.1, Section 3.2.2.4, Section 3.2.3.1, Section 3.2.3.2, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.1, Section 3.2.5.2, Section 3.2.6)
4. Make available for NRC staff audit the deployment location of OIP Item 3 the portable diesel generators. (Section 3.2.1, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.2, Section 3.2.6)
5. Make available for NRC staff audit an evaluation of Related to OIP Item 5 temperature and radiological conditions to ensure that operating personnel can safely access and operate controls and support equipment. (Section 3.2.1, Section 3.2.2.4, Section 3.2.2.5, Section 3.2.2.1 0, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.2, Section 3.2.6)
6. Make available for NRC staff audit analyses demonstrating OIP Item 4 that HCVS has the capacity to vent the steam/energy equivalent of one percent of licensed/rated thermal power (unless a lower value is justified), and that the suppression pool and the HCVS together are able to absorb and reject decay heat, such that following a reactor shutdown from full power containment pressure is restored and then maintained below the primary containment design pressure and the primary containment pressure limit. (Section 3.2.2.1, Section 3.2.2.2)
7. Make available for NRC staff audit the descriptions of local Related to OIP Item 8 conditions (temperature, radiation and humidity) anticipated during ELAP and severe accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, etc.) required for HCVS venting including confirmation that the components are capable of OIP Phase 1 and Phase 2 Rev. 1 Page 65 of 66 December 6, 2015

Enclosure to NL-15-2121 Edwin I. Hatch Nuclear Plant Units 1 and 2 Hardened Containment Venting System (HCVS) Phase 1 and 2 Overall Integrated Plan performing their functions during ELAP and severe accident conditions. (Section 3.2.2.5, Section 3.2.2.3, Section 3.2.2.9, Section 3.2.2.1 0)

8. Make available for NRC staff audit the final sizing evaluation New Item for HCVS batteries/battery charger including incorporation into FLEX DG loading calculation. (Section 3.2.2.4, Section 3.2.3.1, Section 3.2.3.2, Section 3.2.4.1, Section 3.2.4.2, Section 3.2.5.1, Section 3.2.5.2, Section 3.2.6)
9. Make available for NRC staff audit documentation that OIP Item 9 demonstrates adequate communication between the remote HCVS operation locations and HCVS decision makers during ELAP and severe accident conditions. (Section 3.2.2.5)
10. Provide a description of the final design of the HCVS to OIP Item 6 address hydrogen detonation and deflagration. (Section 3.2.2.6)
11. Provide a description of the strategies for hydrogen control OIP Item 6 that minimizes the potential for hydrogen gas migration and ingress into the reactor building or other buildings. (Section 3.2.2.6}
12. Make available descriptions of design details that minimize OIP Item 7 unintended cross flow of vented fluids within a unit and between units. (Section 3.2.2.7)
13. Make available for NRC staff audit descriptions of all Related to OIP Item 8 instrumentation and controls (existing and planned) necessary to implement this order including qualification methods. (Section 3.2.2.9)
14. Make available for NRC staff audit documentation of an Utilizing existing PCIVs that evaluation verifying the existing containment isolation valves, perform a Design Basis relied upon for the HCVS, will open under the maximum function. Per NEI13-02 no expected differential pressure during BDBEE and severe further evaluation required accident wetwell venting. (Section 3.2.2.9)
15. Make available for NRC staff audit the control document for OIP Item 11 HCVS out of service time criteria. (Section 3.4.1)

OIP Phase 1 and Phase 2 Rev. 1 Page 66 of66 December 6, 2015}}

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