Text

Phase 1 (Updated) and Phase 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions..
	ML15352A027
Person / Time
Site:	Dresden
Issue date:	12/16/2015
From:	Kaegi G; Exelon Generation Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	EA-13-109, RS-15-299
	Download: ML15352A027 (73)
	v • d • e

~Exelton Generation Order No. EA-13-109 RS-1 5-299 December 16, 2015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License Nos. DPR-19 and DPR-25 NRC Docket Nos. 50-237 and 50-249

Subject:

Phase 1 (Updated) and Phase 2 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-1 3-1 09)

References:

1. NRC Order Number EA-1 3-109, "Issuance of Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," dated June 6, 2013

2. NRC Interim Staff Guidance JLD-ISG-201 5-01, "Compliance with Phase 2 Order EA-13-1 09, order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions", Revision 0, dated April 2015

3. NEI 13-02, "Industry Guidance for Compliance With Order EA-1 3-1 09, BWR Mark I & II Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions", Revision 1, dated April 2015

4. Exelon Generation Company, LLC's Answer to June 6, 2013, Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-1 09), dated June 26, 2013

5. Exelon Generation Company, LLC Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 30, 2014 (RS-14-058)

6. Exelon Generation Company, LLC First Six-Month Status Report Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated December 17, 2014 (RS-14-302)

7. Exelon Generation Company, LLC Second Six-Month Status Report Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109), dated June 30, 2015 (RS-15-148)

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 December 16, 2015 Page 2

8. NRC letter to Exelon Generation Company, LLC, Dresden Nuclear Power Station, Units 2 and 3 - Interim Staff Evaluation Relating to Overall Integrated Plan in Response to Phase 1 of Order EA-13-109 (Severe Accident Capable Hardened Vents) (TAC Nos. MF4462 and MF4463), dated February 11, 2015 On June 6, 2013, the Nuclear Regulatory Commission ("NRC" or "Commission") issued an order (Reference 1) to Exelon Generation Company, LLC (EGC). Reference 1 was immediately effective and directs EGC to require their BWRs with Mark I and Mark II containments to take certain actions to ensure that these facilities have a hardened containment vent system (HCVS) to remove decay heat from the containment, and maintain control of containment pressure within acceptable limits following events that result in loss of active containment heat removal capability while maintaining the capability to operate under severe accident (SA) conditions resulting from an Extended Loss of AC Power (ELAP). Specific requirements are outlined in Attachment 2 of Reference 1.

Reference 1 requires submission of an Overall Integrated Plan (QIP) by June 30, 2014 for Phase 1 of the Order, and an OIP by December 31, 2015 for Phase 2 of the Order. The interim staff guidance (Reference 2) provides direction regarding the content of the OIP for Phase 1 and Phase 2. Reference 2 endorses industry guidance document NEI 13-02, Revision 1 (Reference 3) with clarifications and exceptions identified in Reference 2. Reference 4 provided the EGC initial response regarding reliable hardened containment vents capable of operation under severe accident conditions. Reference 5 provided the Dresden Nuclear Power Station, Units 2 and 3, Phase 10OIP. References 6 and 7 provided the first and second six-month status reports pursuant to Section IV, Condition D.3 of Reference 1 for Dresden Station.

The purpose of this letter is to provide both the third six-month update for Phase 1 of the Order pursuant to Section IV, Condition D.3, of Reference 1, and the OIP for Phase 2 of the Order pursuant to Section IV, Condition D.2 of Reference 1, for Dresden Nuclear Power Station, Units 2 and 3. 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 I OIP, a list of the Phase 10OIP open items, and addresses the NRC Interim Staff Evaluation open items for Phase 1 contained in Reference 8. Future six-month status reports will

.provide the updates for both Phase 1 and Phase 20OIP implementation in a single status report.

Reference 3, Section 7.0. contains the specific reporting requirements for the Phase 1 and Phase 20OIP. The information in the Enclosure provides the Dresden Nuclear Power Station, Units 2 and 3 HCVS Phase 1 and Phase 20OIP pursuant to Reference 2. The enclosed Phase 1 and Phase 20OIP is based on conceptual design information. Final design details and associated procedure guidance, as well as any revisions to the information contained in the Enclosure, will be provided in the six-month Phase 1 and Phase 20OIP updates required by Section IV, Condition D.3, of Reference 1.

This letter contains no new regulatory commitments. If you have any questions regarding this report, please contact David P. Helker at 610-765-5525.

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-13-109 December 16, 2015 Page 3 I declare under penalty of perjury that the foregoing is true and correct. Executed on the 1 6 th day of December 2015.

Respectfully submitted, Glen T. Kaegi Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosure:

Dresden Nuclear Power Station, Units 2 and 3, Overall Integrated Plan for Phase 1 and Phase 2 Requirements for Reliable Hardened Containment Vent System (HCVS) Capable of Operation Under Severe Accident Conditions cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region Ill NRC Senior Resident Inspector - Dresden Nuclear Power Station NRC Project Manager, NRR - Dresden Nuclear Power Station Mr. Charles H. Norton, NRR/JLD/PPSD/JOMB, NRC Mr. John P. Boska, NRR/JLD/JOMB, NRC Illinois Emergency Management Agency - Division of Nuclear Safety

Enclosure 1 Dresden Nuclear Power Station, Units 2 and 3 Overall Integrated Plan for Phase 1 and Phase 2 Requirements for Reliable Hardened Containment Vent System (HCVS) Capable of Operation Under Severe Accident Conditions (69 pages)

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Table of Contents:

Introduction 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 SAWAISAWM Part 3.1B Boundary Conditions for SAWAISADV Part 4: Programmatic Controls, Training, Drills and Maintenance Part 5: Implementation Schedule Milestones : HCVS/SAWA Portable Eq~uipment A: Seqiuence of Events Timeline - HCVS .1.A: Sequence of Events Timeline - SAWA / SAWM .1.B: Sequence of Events Timeline - SADV .1.C: SAWA / SAWM Plant-Specific Datum .1.D: SAWM SAMG Approved Language : Conceptual Sketches : Failure Evaluation Table : References : Changes/Updates to this Overall Integrated Implementation Plan : List of Overall Integrated Plan Open Items Page 1 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Introduction In 1989, the NRC issued Generic Letter 89-16, "Installation of a Hardened Wetwell Vent," (Reference 2) to all licensees of Boiling Water Reactors (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 suppression pooi to some point outside the secondary containment envelope (usually outside the reactor building). Some licensees also installed a hardened vent branch line from the dryweUl.

On March 19, 2013, the Nuclear Regulatory Commission (NRC) Commissioners directed the staff per Staff Requirements Memorandum (SRM) for SECY-12-0 157 (Reference 26) 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 Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Undter Severe Accidents, June 6, 2013 (Reference 4). The Order (EA-13-109) requires that licensees of BWR facilities with Mark I and Mark II containment designs ensure that these facilities have a reliable hardened vent to remove decay heat from the containment, and maintain control of containment pressure within acceptable limits following events that result in the loss of active containment heat removal capability while maintaining the capability to operate under severe accident (SA) conditions resulting from an Extended Loss of AC Power (ELAP).

The Order requirements are applied in a phased approach where:

"Phase 1 involves upgrading the venting capabilities from the containment wetwell to provide reliable, severe accident capable hardened vents to assist in preventing core damage and, if necessary, to provide venting capability during severe accident conditions." (Completed "no later than staltup 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 instailation of a reliable, severe accident capable drywell vent system or the development of a reliable containment venting strategy that makes it unlikely that a licensee would need to vent from the containment drywell during severe accident conditions." (Completed "no later than startup from the first refueling outage that begins after June 30, 2017, or June 30, 2019, whichever comes first.")

The NRC provided an acceptable approach for complying with Order EA-13-109 through Interim Staff Guidance (ISG) (JLD-ISG-2013-02) issued in November 2013 (Reference 6) and JLD-ISG-2015-01 issued in April 2015 (Reference 31). The ISGs endorse the compliance approach presented in NEI 13-02 Revisions 0 and 1, Compliance with OrderEA-13-109, Severe Accident Reliable Hardened Containment Vents (Reference 9), with clarifications. Except in those cases in which a licensee proposes an acceptable alternative method for complying with Order EA-13-109, the NRC staff will use the methods described in these ISGs to evaluate licensee compliance as presented in submittals required in Order EA-13-109.

The Order also requires submittal of an overall integrated plan which will provide a description of how the requirements of the Order will be achieved. This document provides the Overall 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 requirements of Order EA- 13-109.

Page 2 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents The submittals required are:

OIP for Phase 1 of EA-13.-109 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 1 was due December 2014, with the second due June 2015.

OIP for Phase 2 of EA-13-109 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 20OP submittal by means of a combined Phase 1 and 20IO.

Thereafter, the 6-month updates will be for both the Phase 1 and Phase 2 actions until complete, consistent with the requirements of Order EA-13-109.

Note: Per the Generic OIP, at the Licensee's option, the December 2015 six month update for Phase 1 may be independent of the Phase 20OIP submittal, but will require separate six month updates for Phases 1 and 2 until each phase is in compliance. Exelon has not selected this option.

The Dresden venting actions for the EA-13-109, Phase 1 severe accident capable venting scenario can be summarized by the following:

The Hardened Containment Vent System (HCVS) will be initiated via manual action from either the Main Control Room (MCR) or from a Remote Operating Station (ROS) at the appropriate time based on procedural guidance in response to plant conditions from observed or derived symptoms. The ROS capabilities are limited to the Order EA-13-109 Requirement 1.2.5.

Specifically, in case the HCVS flow path valves or the Argon purge flow cannot be opened from the MCR, the ROS provides a back-up means of opening the valve(s) that does not require electrical power or control circuitry.

The vent will utilize Containment Parameters of Pressure and Suppression Pool 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 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months with installed equipment (EA-13-109, 1.2.6). Replenishment of the motive force will be by use of portable equipment prior to the installed motive force being exhausted.

Venting actions will be capable of being maintained for a sustained period of up to 7 days (NEI 13-02, 4.2.2.1.1).

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). Although SAWA to the Drywell (DW) is an option, Exelon is planning SAWA injection to the RPV.

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 decay heat from containment.

Page 3 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents

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 DW pressure control.

The SAWA and SAWM actions will be manually activated and controlled from areas that are accessible during severe accident conditions.

Parameters measured should be Drywell pressure, Suppression Pool level, SAWA flowrate and the HCVS parameters listed above.

Note: Although EA-13-109 Phase 2 allows selecting SAWA and a Severe Accident Capable Drywell Vent (SADV) strategy, Exelon has selected SAWA and SAWM.

Page 4 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 1: General Integrated Plan Elements and Assumptions Extent to which the guidance, JLD-ISG-2013-02, JLD-ISG-2015-01, and NET 13-02 (Revision 1), are being followed. Identify any deviations.

Include a descriptionof any alternatives to the guidance. A technical justification and basisfor 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 Dresden with no known deviations to the guidelines in JLD-ISG-2013-02, JLD-ISG-2015-01, and NEJ 13-02 for each phase as follows:

The Hardened Containment Vent System (HCVS) will be comprised of installed and portable equipment and operating guidance:

Severe Accident Wetwell Vent (SAWV) - Permanently installed vent from the Suppression Pool to the top of the Reactor Building.

Severe Accident Water Addition (SAWA) - 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 (SAWM) strategies and guidance for controlling the water addition to the RPV for the sustained operating period. (Reference attachment 2.1 .D)

Unit 3 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 4Q20 16.

Unit 2 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 4Q2017.

Unit 2 Phase 2 (alternate strategy): by the startup from the first refueling outage that begins after June 30, 2017, or June 30, 2019, whichever comes first. Currently scheduled for 4Q2017.

Unit 3 Phase 2: (alternate strategy): by the startup from the first refueling outage that begins after June 30, 2017, or June 30, 2019, whichever comes first. Currently scheduled for 4Q20 18.

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

State Applicable Extreme External Hazard from NET 12-06, Section 4.0-9.0 List resultantdetermination of screened in hazardsfrom the EA-12-049 Compliance.

Ref: NET 13-02 Section 5.2.3 and D.1.2 The following extreme external hazards screen in for Dresden:

Seismic, external flooding, extreme cold, high wind, and extreme high temperature.

The following extreme external hazards screen out for Dresden:

NA Key Site assumptions to implement NEI 13-02 Strategies. . ...

Page 5 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 1: General Integrated Plan Elements and Assumptions Provide key assumptions associatedwith implementation of HCVS Phase 1 Strategies.

Ref: NEI 13-02, Revision 1, Section 2 NEI 12-06 Revision 0 Mark Ji/I Generic HCVS Related Assumptions:

Applicable EA- 12-049 (Reference 3) assumptions:

049-1. Assumed initial plant conditions are as identified in NEI 12-06, §3.2.1.2, items 1 and 2 (Reference 8).

049-2. Assumed initial conditions are as identified in NET 12-06, §3.2.1.3, items 1, 2, 4, 5, 6 and 8 (Reference 8).

049-3. Assumed reactor transient boundary conditions are as identified in NEI 12-06, §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 the failure of Reactor Core Isolation Cooling (RCIC) or High Pressure Coolant Injection (HPCI) (Reference NEI 12-06, §3.2.1.3, item 9 [8]).

049-5. At time=0 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.

049-6. At time=l hour (time sensitive at a time greater than 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months ) 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 station battery usage, (greater than approximately 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months with a calculated limiting value of approximately 6 hrs., EC Eval. 391973) (NEI 12-06, section 3.2.1.3 item 8).

049-8. Deployment resources are assumed to begin arriving at hour 6 and fully staffed by 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

049-9. All activities associated with EA-12-049 (FLEX) that are not specific to implementation of the HCVS, including such items as debris removal, communication, notifications, Spent Fuel Pool (SFP) level and makeup, security response, opening doors for cooling, and initiating conditions for the events, can be credited as previously evaluated for FLEX. (Refer to assumption 109-02 below for clarity on SAWA)(HCVS-FAQ-1 1)

Applicable EA-13-109 (Reference 4) generic assumptions:

109-1. Site response activities associated with EA-13-109 actions are considered to have no access limitations associated with radiological conditions while Reactor Pressure Vessel (RPV) level is above 2/3 core height (core damage is not expected). This is further addressed in HCVS-FAQ-12.

109-2. Portable equipment can supplement the installed equipment after 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months provided the portable equipment credited meets the criteria applicable to the HCVS. An example is use of FLEX portable air supply equipment that is credited to recharge air lines for HCVS components after 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The FLEX portable air supply used must be demonstrated to meet the "SA Capable" criteria that are defined in NEI 13-02 Section 4.2.4.2 and Appendix D Section D.l.3 (Reference 9). This assumption does not apply to Phase 2 SAWA/SAWM because SAWA equipment needs to be connected and placed in service within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months from the time of the loss of RPV injection. (Reference HCVS-FAQ-12).

109-3. SFP Level is maintained with either on-site or off-site resources such that the SFP does not contribute to the analyzed source term (Reference HCVS-FAQ-07 [18]).

109-4. Existing containment components design and testing values are governed by existing plant containment Page 6 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 1: General Integrated Plan Elements and Assumptions criteria (e.g., Appendix J) and are not subject to the testing criteria from NEI 13-02 (Reference HCVS-FAQ-05 [16] and NET 13-02, §6.2.2 [9]).

109-5. Classical design basis evaluations and assumptions are not required when assessing the operation of the HCVS. The reason that 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 that classical design basis evaluations are intended to prevent (Reference NEI 13-02, §2.3.1 [9]).

109-6. HCVS manual actions require minimal operator steps and can be performed in the postulated thermal 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-0l[12]). This assumption does not apply to Phase 2 SAWA/SAWM because SAWA equipment needs to be connected and placed in service within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months from the time of the loss of RPV injection and will require more than minimal operator action.

109-7. HCVS dedicated equipment is defined as vent process elements that are required for the HCVS to function in an ELAP event that progresses to core melt ex-vessel (Reference HCVS-FAQ-02 [13] and White Paper HCVS-WP-01 [21]). This assumption does not apply to Phase 2 SAWA/SAWM because SAWA equipment is not dedicated to HCVS but shared to support FLEX functions. This is further addressed in HCVS-FAQ-il1.

109-8. Use of MAAP Version 4 or higher provides adequate assurance of the plant conditions (e.g., RPV water level, temperatures, etc.) assumed for Order EA-13-109 Beyond Design Basis External Event (BDBEE) and SA HCVS operation (Reference FLEX MAAP Endorsement ML13190A201 [29]). Additional analysis using RELAP5/MOD 3, GOTHIC, and MICROSHIELD, etc., are acceptable methods for evaluating environmental conditions in other portions of the plant, provided that the specific version utilized is documented in the analysis. MAAP Version 5 was used to develop EPRI Technical Report 3002003301 to support diywell temperature response to SAWA under severe accident conditions.

109-9. NRC Published Accident evaluations (e.g., SOARCA, SECY-12-0157, NUREG 1465) as related to Order EA-13-109 conditions are acceptable as references (Reference NEI 13-02, §8 [9]).

109-10. Permanent modifications installed or planned per EA-12-049 are assumed implemented and may be credited for use in Order EA-13-109 response.

109-11. This Overall Integrated Plan is based on Emergency Operating Procedure (EOP) changes consistent with Emergency Procedures Guidelines/Severe Accident Guidelines (EPG/SAGs) Revision 3 as incorporated per the site's EOP/Severe Accident Procedure (SAP) procedure change process. This assumption does not apply to Phase 2 SAWM because SAWM is not part of revision 3. (Refer to Attachment 2.1.D for SAWM SAMG changes approved by the BWROG Emergency Procedures Committee.)

109-12. Under the postulated scenarios of Order EA-13-109, the Main Control Room is adequately protected from excessive radiation dose as per General Design Criterion (GDC) 19 in 10CFR50 Appendix A and no further evaluation of its use as the preferred HCVS control location is required provided that the HCVS routing is a sufficient distance away from the MCR or is shielded to minimize impact to the MCR dose. In addition, adequate protective clothing and respiratory* protection are available if required to address contamination issues (Reference HCVS-FAQ-0l [12] and HCVS-FAQ-09).

109-13. The suppression pool/wetwell of a BWR Mark I/II containment is considered to be hounded by assuming a saturated environment for the duration of the event response because of the water/steam interactions.

Page 7 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 1: General Integrated Plan Elements and Assumptions 109-14. RPV depressurization is directedt by the EPGs in all cases prior to entry into the SAGs. (reference NEI 13-02 Rev 1 §1.1.3) 109-15. The Severe Accident impacts are 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-13-109 ensure the capability to protect containment exists for each unit. (HCVS-FAQ-01) This is further addressed in HCVS-FAQ-10.

Plant Specific HCVS Related Assumptions/Characteristics:

Dresden-i Provided Severe Accident (SA) conditions are not reached EA- 12-049 (FLEX) actions to restore power are sufficient to ensure continuous operation of non-dedicated containment instrumentation identified in Part 2 (Key Venting Parameters) of this OIP. Modifications that allow a FLEX generator to recharge the HCVS battery are assumed to have been installed such that a FLEX generator can be credited for HCVS operation beyond the initial 24-hour sustained operational period. If SA conditions are reached, these non-dedicated containment instruments will be monitored by use of hand held, test instrumentation that rely on small batteries, and Dresden will provide a small portable generator to maintain HCVS battery charge beyond the initial 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

Dresden -2 In case of a severe flood warning, the Dresden units will be shutdown and cooldown (per procedure DOA 00 10-04) prior to the flooding causing an ELAP. The shutdown and cooldown prior to the ELAP will significantly reduce the decay heat that would have to be removed by the Isolation Condenser System (ICS) or, in case of a failure of the ICS, by the HCVS. Dresden will evaluate what actions may be necessary to ensure the WW venting path remains viable following a severe flood. Reactor building dewatering strategy is under development and will be updated in the next 6-month update (Ref. ISF Open Item 2).

Dresden -3 The Plant layout of buildings and structures are depicted in Sketches 2B and 2C. Note the Main Control Room is located at Control Building elevation 534'. The Control Building has substantial structural walls and features independent of the Reactor Building. The HCVS vent routing external to the Reactor Building is indicated on Sketch 2-C. The external piping is vertical with the exception of the point at which it exits the Reactor Building.

Dresden -4 The HCVS external piping is all above 30-feet from ground level and it consists solely of large bore (10-inches nominal diameter piping and its piping supports (EC 400578). The external piping has less than 300 square feet of cross section. The HCVS external piping meets the reasonable protection requirements of HCVS-WP-04. The external support structure used to support the HCVS piping is analyzed to the Dresden design basis tornado missiles to preclude a failure of the tower due to tornado winds and missiles.

Page 8 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell 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 constraintto be successful should be identified with a technical basis and a justificationprovided that the tine 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 basisfor the constraints identified on the sequence of events timneline attachment.

See attached sequence of events tirneline (Attachment 2A ).

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 containment purge exhaust at each Dresden unit consists of a wetwell primary containment isolation valve (PCIV), a DW PCIV, and a common downstream PCIV. The HCVS flow path will utilize portions of this system. The HCVS will connect between the two containment purge exhaust PCIVs. Consequently, the HCVS flow path will share the upstream PCIVs with the containment purge system, but it will have a downstream PCIV dedicated to the HCVS flow path. The new HCVS flow path will have a rupture disc downstream of the last PCIV on the HCVS line to serve as the secondary containment leakage barrier.

Each unit will have piping that is totally separate from the other unit and with no interconnected systems downstream of the new downstream PCIV. The discharge from each unit is routed separately and discharges above the unit's Reactor Building roof.

The two Dresden units will have a dedicated motive power (Pressurized N2) for HCVS valves, Argon Purge system, and DC power for HCVS components that, except for battery charging after 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , does not rely on FLEX (EC 400578).

Existing containment instruments (pressure and suppression pool level) are not considered HCVS components and power will be maintained through the actions for EA-12-049 for non-severe accident conditions or using test equipment during severe accident conditions.

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 trained 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 (Table 2-1). A HCVS ELAP Failure Evaluation table, which shows alternate actions that can be performed, is included in Attachment 4.

Table 2-1 HCVS Remote Manual Actions Page 9 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent Primary Action Primary Location!/ Notes Component

1. Energize the HCVS power supply MCR to the HCVS components

2. Enable the N2 motive air for the ROS* . . . . .. - - -

HCVS valves

3. CeckshuttheDW PIV (3)- MCRPrecautionary steps; these valves are normally shut 160 1-23, the downstream PCIV to and fail shut.

the containment purge exhaust 2(3)-1601-24, and downstream PCIV to the SGTS 2(3)-1601-63 MCR Only required if venting is initiated at a opening the Argon Purge Line for containment pressure below the rupture disc the specified amount of time setpoint (40 psid).

WetelntPCnVe23)4601-60iverride.th

5. Open cnanetioaon Alternate control via motive air manual valves at signal by opening the the ROS.

PCIV in the HVCS P~nPl

6. Open the downstream PCIV 2(3)- Key locked hand Alternate control via motive air manual valves at 1601-93 on the common HCVS switch located in the the ROS.

line HVCS Panel

7. Align FLEX Generator to As described in Prior to depletion of station battery. Required to maintain power to Station Battery response to EA maintain power to containment instrumentation.

049.. . . . . . . ..

It P~LtN, LXJi not availalae (i.e., under SA conditions), DW pressure and suppression pool

, level will be monitored using test equipment.

8. Align generator to HCVS battery At ROS Prior to depletion of the HCVS battery supply, charger. actions will be required to recharge the battery.

If FLEX DG is not available (i.e., under SA conditions), a small portable generator will be used

9. Replace N2 motive power bottles Replacement Nitrogen Prior to depletion of the pneumatic sources, actions or align portable compressor bottles and/or i.will be required to connect back-up sources at a compressor will be itime greater than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

located at the ROS.

10. R~eplace-Ar-gon-puirge-gas- bottles ......... t.RO~S .............. -irior-to P... diepletion of the-Argon purge supply-at a......

time greater than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . Required only if SA conditions are reached.

ROS - Remote Operating Station......

Page 10 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent A, Sequence of Events Timeline, was developed to identify required operator response times and potential environmental constraints. This timeline is based upon the following three sequences:

1. Sequence 1 is based upon the action response times developed for FLEX when utilizing anticipatory venting in a BDBEE without core damage. Containment venting is not required for Dresden FLEX response since the Isolation Condenser System (ICS) removes all the decay heat from the reactor and the containment does not become pressurized enough to require venting.

Dresden does not have a RCIC system but it has a steam driven High Pressure Coolant Injection System (HPCI).

2. Sequence 2 is based on SECY-12-0157 long-term station blackout (LTSBO) (or ELAP) with a failure of RCIC after a black start where failure occurs because of subjectively assuming over injection. It is used for Dresden to represent a late failure of the ICS and HPCI. Late failure of the ICS is due to the assumption that FLEX fails to provide make-up water to the ICS.

3. Sequence 3 is based on NUREG-1935 (SOARCA) results for a prolonged SBO (or ELAP) with loss of RCIC case without black start. For Dresden, this represents that the ICS fails after its initial water volume is expended (i.e., no FLEX make-up to the ICS), and the HPCI fails early at a pool temperature of 140°F [MAAP case 8].

The following is a discussion of time constraints identified in Attachment 2A for the 3 timeline sequences identified above:

With case 1 (ICS operating), HCVS operation is not required since the only heat input into the containment is from RCS leaks and ambient losses to the environment.

For case 3 (limiting case), in approximately 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months , initiate use of Hardened Containment Vent System (HCVS) per site procedures to maintain containment parameters below the lower of Primary Containment Pressure Limit (PCPL) or contalnment design pressure.

Reliable operation of HCVS will be met because HCVS meets the seismic requirements

identified in NEl 13-02, will be powered by DC power from a dedicated power source, and HCVS valves are supplied with motive force from portable nitrogen bottles. HCVS controls and instrumentation and controls will be DC powered. HCVS valve motive force is from pressurized gas. Valves will be operable from the HCVS control panel in the MCR. DC power and motive air will be available for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months from permanent sources. Containment pressure and WW indication will initially be powered from existing lE Station battery. If SA conditions are not reached, these containment indications will be maintained by FLEX generators. If SA conditions are reached, these indications will be monitored by hand held instruments powered from small batteries. Thus, initiation of the HCVS from the MCR or the Remote Operating Station within approximately 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months is acceptable because the actions can be performed any time after declaration of an ELAP until the venting is needed at approximately 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months for BDBEE venting. This action can also be performed for SA HCVS operation which occurs at a time further removed from an FLAP declaration as shown in Attachment 2.

Within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , the permanently installed nitrogen bottles at the ROS will be replaced, as required, to maintain sustained operation or alternatively a portable compressor will be connect at the ROS. Typical of all activities required at 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , this can be performed at Page 11 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent any time prior to 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to ensure adequate capacity is maintained so this time constraint is not limiting.

Within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , the permanently installed Argon bottles at the ROS will be replaced, as required, to maintain sustained operation. Note that purging is only required if venting hydrogen following severe accident conditions.

Within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , a generator will be installed and connected to recharge the dedicated HCVS power supply to maintain sustalned operation. Under non-SA conditions this will be the FLEX generator. Under SA conditions this will be a small, portable generator.

Current Dresden station battery durations are calculated to last 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . if SA conditions are not reached, FLEX pre-staged DG will be in service 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months after an event (Reference FLEX 0TP). Modifications will be implemented to facilitate the connections and operational actions required to supply power within approximately 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months . Thus, under non-SA conditions, the FLEX DGs will be available to be placed in service at any point after approximately 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months as required to supply power to containment parameters (containment pressure and WW level). A FLEX DG will be maintained and used in on-site FLEX storage buildings. For the flood event, the DG will be transferred and staged via haul routes and staging areas evaluated for impact from external hazards.

Discussion of radiological, temperature. other environmental constraints identified in Attachment 2A

Actions to initiate HCVS operation are taken from the MCR or from the ROS in the Turbine Building. Both locations have significant shielding and/or physical separation fr'om radiological sources. Non-radiological habitability for the MCR is being addressed as part of the Dresden FLEX response. The ROS location in the Turbine Building has no heat sources.

Before the end of the initial 24-hour period, replenishment of the HCVS dedicated DC power, Argon purge gas, and PCIV motive power (pressurized gas) will occur at the ROS. The selection of the ROS location will take into account the SA temperature and radiation condition to ensure access to the ROS is maintained. The design will allow replenishment with minimal actions.

ISE Open Item - 12: Confirm that the ROS will be in an area accessible following a SA.

Provide Details on the Vent characteristics.

Vent Size and Basis ('EA-13-!09 Section 1.2.1 /NE1 13-02 Section 4.1.1)

What is the plants licensed power? Discuss any plansfor possible increases in licensedpower (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, PCPL, or some other criteria(e.g. anticipatory venting)?

Vent Capacity (EA 1 09 Section 1.2.1/INEI 13-02 Section 4.1.1)

Indicate any exceptions to the 1% decay heat removal criteria, including reasonsfor the exception.

Provide the heat capacity of the suppressionpool in terms of time versus pressurizationcapacity, assuming suppressionpool is the injection source.

Page 12 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent Vent Pathand Discharg~e (EA-13-109 Section 1.1.4. 1.2.2 / NEI 13-02 Section 4.1.3, 4.1.5 and Appendix Provide a description of Vent path, release path, and impact of vent path on other vent element items.

Power and Pneumatic Supply Sources (EA 1 09 Section 1.2.5 & 1.2.6 /NEI 13-02 Section 4.2.3. 2.5, 4.2.2, 4.2.6. 6.1)

Provide a discussion of electricalpower requirements, including a descriptionof dedicated 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months power supply from permainently installed sources. Include a similardiscussion as above for the valve motive force requirements. Indicate the area in the plantfrom where the installed/dedicatedpower and pneumatic supply sources are coming.

Indicate the areas where portable equipmnent will be staged after the 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months period, the dose fields in the area, andt any shielding that would be necessary in that area.

Location of ControlPanels (EA 1 09 Section 1.1.1, 1.1.2, 1.1.3. 1.1.4, 1.2.4, 1.2.5 /NEI 13-02 Section 4,1.3. 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.

.Hydrog'en(EA-13.109 Section 1.2.10, &1.2.11, and 1.2.12/INEI 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 plant will take to address the control of fiammable gases, clearly demarcating the segments of vent system to which an approach applies.

Unintended Cross Flow of Vented Fluids (EA 1 09 Section 1.2.3, 1.2.12 / NEI 13-02 Section 4.1.2, 4,1.4, 4.1.6andAppendix H)

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

Prevention of lnadvertent Actuation (EA-13-109 Section 1.2.7/NEl 13-02 Section 4.2.1)

The HCVS shall include means to prevent inadvertentactuation.

Component Qualifications(EA-13-109 Section 2.1/INEI 13-02 Section 5.1)

State qualificationcriteria based on use of a combination of safety related and augmented quality dependent on the location,function andt interconnectedsystem requiremnents.

_Monitoring of HCVS (Order Elements 1.1.4, 1.2.8, 1.2.9/NEI 13-02 4.1.3, 4.2.2, 4.2.4, andAppendix FIG)q Provide a descriptionof instruments used to monitor HCVS operation and effluent. Powerfor an instrument will require the intrinsically safe equipment installed as part of the power sourcing.

Comnonent reliable and rugv'ed oerformance (EA 1 09 Section 2.2 /NEI 13-02 Section 5.2. 5.3)

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

Page 13 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent Components including instrumentationthat 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 functionalityfollowing a seismic event. (Reference JLD-ISG-2012-01 and JLD-ISG-2012-O3for seismic details.)

The components including instrumentationexternal to a seismic category I (or equivalent building or enclosure should be designed to meet the external hazards that screen in for the plant as defined in guidance NE1 12-06 as endorsed by JLD-ISG-12-O1 for Order EA-12-049.

Use of instruments and supporting components with known operatingprinciples that are supplied by manufacturerswith commercial quality assuranceprograms, such as 1S09001. The procurement specifications shall include the seismic requirements and/or instrument design requirements, and specify the need for commercial design standardsand testing under seismic loadings consistent with design basis values at the instrument locations.

Demonstration of the seismic reliability of the instrumentation through methods that predict performance by analysis, qualificationtesting 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 JE Equipment for Nuclear Power GeneratingStations,'"or a substantially similar industrial standtardcould be used.

Demonstration that the instrumentation is substantially similar in design to instrumentationthat 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 andfrequency ranges). Such testing and analysis should be similar to that performedfor the plant licensing basis.

Page 14 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent Vent Size and Basis The HCVS flow path is designed for venting steanm/energy from the suppression pooi at a nominal capacity of 1% of the currently licensed power, 2957 MWt thermal power at pressure of 62 psig (UFSAR Table 1.2-1). This pressure is the lower of the containment design pressure and the PCPL value assuming nominal torus water level. The nominal diameter is 18-inches through the shared upstream PCTV that is shared with the containment purge exhaust and 10-inches for the downstream portion. The 10-inch diameter portion includes the downstream PCIV and rupture disc. Refer to Sketch 2A, the P&TD. This line has been verified to meet the Order criteria for 1%.

Vent Capacity The 1% value at Dresden assumes that the suppression pooi pressure suppression capacity is sufficient to absorb the decay heat generated during the first 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months . 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 was confirmed to exceed 3 hours3.472222e-5 days 8.333333e-4 hours 4.960317e-6 weeks 1.1415e-6 months (Reference 37, MAAP).

Vent Path and Discharge The Dresden station HCVS vent path will consist of a separate wetwell vent for each unit. The upstream portion consists of 18-inch nominal diameter piping and the upstream PCIV that is shared with the torus containment purge exhaust path. The downstream portion consists of 10-inch nominal diameter piping and includes the downstream PCIV and the rupture disc. The downstream PCTV and rupture disc are dedicated to the HCVS function. The rupture disc is credited as the secondary containment isolation barrier. The 10-inch diameter vent line is initially routed vertically with the Reactor Building and then horizontally through the Reactor Building wall at elevation 591', which is approximately 74 feet above nominal plant ground elevation (EC 401069, DWG M-1 194A-1). This line is then routed vertically on the outside of the Reactor Building to a point above the top of the Reactor Building. There are no interconnected systems downstream of the second PCIVs and there is no sharing of any flow path between the two units.

The HCVS discharge path is being routed to a point above any adjacent structure. This discharge point is just above that unit's Reactor Building and will follow the guidance of FAQ- HCVS-04 (Reference 15) to the extent reasonably possible such that the release point will vent away from emergency ventilation system intake and exhaust openings, main control room location, location of HCVS portable equipment, access routes required following a ELAP and BDBEE, and emergency response facilities; however, these must be considered in conjunction with other design criteria (e.g., flow capacity) and pipe routing limitations, to the degree practical. The external vertical piping for the two units will be run in close proximity to each other to allow a common external support structure. The external piping meets the criteria for tornado missile reasonable protection (refer to Dresden Assumption 4).

Power and Pneumatic Supply Sources All electrical power required for operation of HCVS components will be from a dedicated HVCS DC battery source with permanently installed capacity for the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months and design provisions for recharging to maintain sustained operation.

Motive (pneumatic) power to the HCVS valves is provided by a dedicated bank of N2 gas bottles with permanently installed capacity for the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months and design provisions for replacing bottles and/or Page 15 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent connecting a portable compressor to maintain sustained operation. The initial stored motive air/gas will allow for a minimum of 8 vent cycles for the HCVS valves for the first 24-hours. The 8 vent cycles is defined as initially opening all valves in the wetwell flow path, and then shutting and reopening one of the valves in the flow paths.

1. The HCVS flow path valves are air-operated valves (AOV). The existing, upstream PCIV is air-to-open and air-to-shut. The new downstream PCIV will be air-to-open and spring-to-shut. Opening the valves from the HCVS control panel located in the MCR requires energizing a DC powered solenoid operated valve (SOV) and providing motive air/gas.

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

3. All permanently installed HCVS equipment, including any connections required to supplement the HCVS operation during an ELAP (i.e., DC power, Argon purge gas, and motive force [pressurized N2/air]) will be located in areas reasonably protected from defined hazards listed in Part 1 of this report.

47All valves required to open the flow path 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 handwheel, reach-rod or similar means that requires close proximity to the valve (reference FAQ HCVS-03).

The preferred method is opening from the MCR through the control switch that energizes the AOV's SOV. The back-up method for new valves is from the ROS by repositioning valves on the pneumatic supply; this allows opening and closing of a valve from the ROS without reliance on any electrical power or control circuit. Accessibility to the ROS will be verified during the detailed design.

5. 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) and in addition, opening PCTVs and the Argon purge system from the ROS in case of a DC circuit failure. The tentative location for the ROS is 561 foot elevation Turbine Building. The MCR location is protected from adverse natural phenomena and it is the normal control point for Plant Emergency Response actions. The ROS will be evaluated to ensure acceptable temperature and dose consequences.

Hydroigen As required by EA-13-109, Section 1.2.11, the HCVS design will include an Argon purge system that will be connected just downstream of the second PCIV. It will be designed to prevent hydrogen detonation downstream of the second PCIV. The Argon purge system will have a switch for the control valve in the MCR to allow opening the purge for the designated time, but it will also allow for local operation in the ROS in case of a DC power or control circuit failure. The Argon purge will only be utilized following severe accident conditions when hydrogen is being vented. The installed capacity for the Argon purge Page 16 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent system will be sized for at least 8 purges within the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of the ELAP. This number of vent cycles is the same value used for sizing the PC1V motive air supply. The design will allow for Argon bottle replacement for continued operation past 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months .

The Argon purge system can also be used to breach the rupture disc if venting is required before reaching the rupture disc setpoint. The MCR panel will include an indication of Argon pressure to the HCVS path to verify that the Argon purge system flow is occurring.

Unintended Cross Flow of Vented Fluids Refer to Sketch 2A, the HCVS P&IID. The HCVS piping in each unit is totally independent of the other unit's HCVS flow path. The upstream 18-inch nominal diameter portion isolates any interconnected, non-HCVS systems in that unit through normally shut, air-operated PCIVs that, if open, will automatically shut.

The downstream dedicated 10-inch portion does not have any interconnected systems. This precludes unintended cross flow of vented fluids.

Prevention of Inadvertent Actuation EOP/ERG operating procedures provide clear guidance that the HCVS is not to be used to defeat containment integrity during any design basis transients and accident. In addition, the HCVS will be designed to provide features to prevent inadvertent actuation due to a design error, equipment malfunction, or operator error such that any credited containment accident pressure (CAP) that would provide net positive suction head to the emergency core cooling system (ECCS) pumps will be available (inclusive of a design basis loss-of-coolant accident (DBLOCA)). However, the ECCS pumps will not have normal power available because of the starting boundary conditions of an ELAP.

Note that Dresden credits CAP for its DBLOCA. Preventing inadvertent operation is addressed. The features that prevent inadvertent actuation are two PCI Vs in series with a downstream rupture disc. The downstream PCIV is a normally shut, fail-shut AOV dedicated to the HCVS function. This valve is air to open; spring to shut that requires energizing a SOV to allow the motive air to open the valve. This PCTV is controlled by its own key-locked switch. In addition, the DC power to its SOV and the motive air supplied will normally be disabled to prevent inadvertent operation.

Component Qualifications The HCVS components and components that interface with the HCVS are routed in seismically qualified structures.

HCVS components that are part of the containment pressure boundary will be safety-related. The containment system limits the leakage or release of radioactive materials to the environment to prevent offsite exposures from exceeding the guidelines of 10 CFR 100. During normal or design basis operations, this means serving as a pressure boundary to prevent release of radioactive material. HCVS components downstream of the containment pressure boundary (i.e., downstream of the downstream PCIV) will not be safety-related.

The HCVS components (SOVs and instrumentation) will be powered from a normally de-energized, dedicated power supply that will not be safety-related but will be considered Augmented Quality.

However, if any HCVS electrical or controls component interfaces with Class 1E power sources, it will he 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. Newly installed piping and valves will be seismically analyzed to handle the forces associated with the Plant's Design Basis Seismic Requirements back to their isolation boundaries. Electrical and controls components Page 17 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent will be seismically analyzed 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 determine core conditions (i.e., no core damage thru severe core damage). 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., 1S09001) 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 1509001 / IEEE 344-2004 / Demonstration HCVS Process Radiation Monitor 1S09001 / IEEE 344-2004 / Demonstration HCVS Valve Position Indication 1509001 I IEEE 344-2004 I Demonstration HCVS Pneumatic Supply Pressure ISO09001 / IEEE 344-2004 / Demonstration HCVS Electrical Power Supply Availability 1SO9001 / IEEE 344-2004 I Demonstration HCVS Argon System Purge Pressure 1SO900 1/ IEEE 344-2004 I Demonstration

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

[ISE OPEN ITEM-15: Complete evaluation for HCVS instrumentation qualification.]

Monitoring of HCVS The Dresden wetwell HCVS will be capable of being remote-manually operated during sustained operations from a control panel located in the main control room (MCR) and will meet the requirements of Order element 1.2.4. The MCR is a readily accessible location with no further evaluation required (Generic Assumption 109-12). Additionally, to meet the requirement of EA-13-109 Section 1.2.5, an accessible Remote Operating Station (ROS) will also be incorporated into the HCVS design as described in NEI 13-02 section 4.2.2.1.2.1. The controls and indications at the ROS location will be accessible and functional under a range of plant conditions, including severe accident conditions with due consideration to source term and dose impact on operator exposure, extended loss of AC power (ELAP), and inadequate containment cooling. An evaluation will be performed to determine accessibility to the ROS location, habitability, staffing sufficiency, and communication capability with Vent-use decision makers.

Page 18 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent The wetwell HCVS will include means to monitor the status of the vent system in the MCR and to monitor DC power, Argon pressure, and N2 pressure at the ROS. The proposed design for the HCVS includes control switches in the MCR with valve position indication. The HCVS controls will meet the environmental and seismic requirements of the Order for the plant severe accident with an ELAP. The ability to open/close these valves multiple times during the event's first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months will be provided by dedicated motive air and DC power. Beyond the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , the ability to maintain these valves open or closed will be maintained by sustaining the motive air and DC power.

The wetwell HCVS will include indications for vent pipe temperature and effluent radiation levels at the MCR. Other important information on the status of supporting systems, (i.e., DC power source status, Argon purge gas pressure and pneumatic supply pressure), will also be included in the design and located to support HCVS operation. Other instrumentation that supports HCVS function will be provided in the MCR. This includes existing containment pressure and suppression pool level indication. This instrumentation is not required to validate HCVS function and is therefore not powered from the dedicated HCVS batteries. However, these instruments are expected to be available since (a) under non-SA conditions the FLEX DG supplies the station battery charger for these instruments and will be installed prior to depletion of the station batteries and (b) under SA conditions, they will be monitored using hand-held test equipment.

Component reliable and rugged performance Unless otherwise required to be safety-related, Augmented Quality requirements will be applied to the components installed in response to this Order.

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, Seismic Category 1, B31.l) for the plant and to ensure functionality following a design basis earthquake.

Additional modifications required to meet the Order will provide reliability at the postulated vent pipe conditions (temperature, pressure, and radiation levels). The instrumentation/power supplies/cables/connections (components) will be qualified for temperature, pressure, radiation level, total integrated dose radiation appropriate for that location (e.g., near the effluent vent pipe or at the HCVS ROS location).

Conduit design and/or cable trays will be installed to Seismic Class 1 criteria.

Dresden complies with HCVS-WP-04 from reasonable protection of HCVS components located outside of seismic Class 1 concrete structures.

If the instruments are purchased as commercial-grade equipment, they will be qualified to operate under severe accident environment as required by NRC Order EA-13-109 and the guidance of NEI 13-02. The equipment will be qualified seismically (IEEE 344) and environmentally (IEEE 323). These qualifications will be bounding conditions for Dresden per UFSAR 1.1.8 and 3.11.

For the instruments required after a potential seismic event, the following methods will be used to verify Page 19 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for Wetwell Vent that the design and installation is reliable / 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;

adequacy of seismic design and installation is demonstrated based on the guidance in Sections 7, 8, 9, and 10 of IEEE Standard 344-2004, IEEE Recommended Practicefor Seismic Qualificationof Class JE Equipmentfor Nuclear Power Generating Stations, (Reference 28) 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); or

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

Page 20 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents 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 /NEI 13-02 Section 2.2 First 24 Hour Coping Detail Provide a general description of the venting actions forfirst 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 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 reliance on operator actions for response to an ELAP and severe accident events. Immediate operator actions will be completed by qualified plant personnel from either the MCR or the HCVS ROS using remote-manual actions. 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. This location minimizes plant operators' exposure to adverse temperature and radiological conditions and is protected from hazards assumed in Part 1 of this report.

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

System control:

i. Active: The PCI Vs will be operated in accordance with EOPs/SOPs to control containment pressure. The HCVS will be designed for at least 8 vent cycles under ELAP conditions over the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months following an ELAP. Controlled venting will be permitted in the revised EPGs and associated implementing EOPs.

ii. Passive: Inadvertent actuation protection is provided by:

A key locked switch for the dedicated downstream PCIV located in the Main Control Room and controlled by procedures AND Disabling the HCVS DC power to the SOV and disabling the motive power (pressurized N2) for the dedicated PCIV except when required by procedures to initiate containment venting AND A rupture disc downstream of the PCIVs with a design pressure of 40 PSID.

Page 21 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for WW Vent - BDBEE Venting Greater Than 24 Hour Coping Detail Provide a general description of the venting actionsfor greaterthan 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months using portable and installed equipment including station modifications that are proposed.

Ref: EA-13-109 Section 1.2.4 / NEI 13-02 Section 4.2.2 Before the end of the 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months initial phase, available personnel will be able to connect supplemental air/gas for the motive air system. Connections for supplementing electrical power and air/gas required for HCVS will be located in accessible areas with reasonable protection per NEI 12-06 that minimize personnel exposure to adverse conditions for HCVS initiation and operation. Connections will be pre-engineered quick disconnects to minimize manpower resources. Replenishment of the Argon supply is not required under non-SA conditions since purging is not required.

FLEX is credited to sustain power for a BDBEE ELAP to containment instruments used to monitor the containment (e.g., pressure and wetwell level) during non-Severe Accident (SA) conditions. Portable instruments will be used during SA conditions. The response to NRC EA-12-049 will demonstrate the capability for FLEX efforts to maintain the power source.

These actions provide long term support for HCVS operation for the period beyond 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 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/IGuidelines:

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

Primary Containment Control Flowchart will be provided to direct operations in protection and control of containment integrity, including use of the existing Hardened Containment Vent System.

These flowcharts are being revised as part of the EPG/SAGs Revision 3 updates and associated EOP/SAP implementation. HCVS-specific procedure guidance will be developed and implemented to support HCVS implementation.

ISE Open Item 18: - Provideproceduresfor HCVS Operation.

Identify modifications:

List modifications and describe how they support the HCVS Actions.

EA- 12-049 Modifications

No additional EA-12-049 modifications are required to support HCVS.

EA-13-109 Modifications

A modification will be required to install the new wetwell vent piping including the new downstream PCIV and rupture disc. The rupture disc controls primary containment leakage during a design basis Page 22 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for WW Vent - BDBEE Venting LOCA. The new valve will include valve position indication and remote-manual control only. There is no sharing of any flow paths with the opposite unit.

A modification will be required to allow operation of the existing upstream wetwell PCIV. This includes the capability to override a containment isolation signal. Reopening the valves following a BDBEE will be remote-manual.

A modification will be required to install the dedicated batteries needed to supply power to HCVS for the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months including capability for recharging from a portable charger at or before 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The battery will be located at the ROS.

A modification will be required to install the dedicated motive power (Pressurized N2 gas) needed to open the HCVS valves for the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months including capability for replacing N2 bottles or connection a portable compressor after 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . The N2 bottles will be located at the ROS.

A modification will be required to install the dedicated Argon purge system. For non-SA conditions, the Argon purge system is not required to prevent hydrogen detonation in the piping. The Argon purge system, however, can be credited with breaching the rupture disc if venting is initifated at a containment pressure below the rupture disc setpoint.

A modification will be required to add (a) HCVS flow path instrumentation consisting of temperature and effluent radiation in the MCR and (b) Motive power and DC HCVS battery indication in the MCR and the ROS.

Key Venting Parameters:

List instrumentationcreditedfor 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. Indication for these parameters will be installed in the MCR or ROS to comply with EA-13-109:

Key Parameter Component Identifier Indication Location HCVS Effluent temperature TBD MCR HCVSEfflentRaditionTBDMCR HCVS valve position indication TBD MCR HCVS DC Power Voltage/Conditions TBD ROS HCVS Pneumatic supply pressure TBD ROS HCVS Purge System pressure TBD MCRIROS Initiation and cycling of the HCVS will be controlled based on several existing MCR key parameters and indicators which are qualified to the existing plant design: (Reference NEI 13-02 Section 4.2.2.1.9 [91):

Key Parameter Component Identifier Indication Location Drywell pressure 2(3)-1640-1 1A(B) MCR

____ wetwell level 2(3)-1640-13A(B) MCR Notes: None Page 23 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents 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 /NEI 13-02 Section 2.3 First 24 Hour Coping Detail Provide a general description of the venting actionsfor first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months using installed equipment including station modifications that are proposed.

Ref: EA-13-109 Section 1.2.6 / NET 13-02 Section 2.5, 4.2.2 Severe accident (SA) conditions assume that specific core cooling actions from the FLEX strategies identified in the response to Order EA-12-049 were not successfully initiated. Core damage is assumed to start at 1.9 hours1.041667e-4 days 0.0025 hours 1.488095e-5 weeks 3.4245e-6 months .

(MAAP Case 8, Reference 37). This case assumes ICS is automatically initiated at the start of the ELAP but secured at T=20 minutes (no credit for make-up to the ICS) and failure of the HPCJ when suppression pooi temperature reaches 140°F. The operator actions required to open a vent path under SA conditions are the same as previously listed in the BDBEE Venting Part 2 section of this report (Table 2-1). The operation of the HCVS under SA conditions is the same as discussed under BDBEE (i.e., non-SA conditions) with the following exceptions:

Access is not restricted prior to core damage. Thereafter, access to the reactor building will be restricted as determined by the RPV water level and core damage conditions.

HCVS permanently installed power, Argon purge, and motive air/gas capability will be available to support operation and monitoring of the HCVS for 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . Specifics are the same as for BDBEE Venting Part 2.

Containment instrumentation (DW pressure and suppression pool) will be monitored using test instruments that are powered from self-contained batteries following depletion of the Station battery.

A preliminary evaluation of travel pathways for dose and temperature concerns has been completed and travel paths identified (ISE Open Item #12). A final evaluation of environmental conditions will be completed as part of detailed design for confirmation.

[ISE OPEN ITEM-12: Confirm travel path accessibility.]

System control:

i. Active: Same as for BDBEE Venting Part 2.

ii. Passive: Same as for BDBEE Venting Part 2 Greater Than 24 Hour Coping Detail Provide a general descriptionof the venting actionsfor greater than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 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 Page 24 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for WW Vent - Severe Accident Venting Specifics are the same as for BDBEE Venting Part 2 except that (a) Argon purge gas replenishment is required after 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months and (b) under SA conditions the FLEX DG will not be available and, consequently, the DW pressure and suppression pooi level indications will be monitored using hand held instruments. The HCVS support systems (including the Argon purge system) will be designed to allow replenishment under SA conditions. These actions provide long term support for HCVS operation for the period beyond 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 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 / Guidelines:

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

The operation of the HCVS will be governed the same for SA conditions as for BDBEE conditions. 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.

Modifications are the same as for BDBEE Venting Part 2 with the exception that a suitable location for connecting test instruments for DW pressure and suppression pool water level will be required.

Key Venting Parameters:

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

Key venting parameters are the same as for BDBEE Venting Part 2.

Notes: None Page 25 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for WW Vent - Support Equipment Functions Determine venting capability support functions needed.

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

Ref: EA-13-109 Section 1.2.9 / NET 13-02 Section 2.5, 4.2.2, 4.2.4, 6.1.2 All containment venting functions will be performed from the MCR or ROS.

Venting to prevent containment overpressurization will be maintained by permanently installed equipment. The HCVS dedicated DC power source, Argon purge gas, and dedicated motive force is adequate for the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months , but it can be replenished to support sustained operation.

Existing safety related station batteries will provide sufficient electrical power for MCR containment instrumentation for greater than approximately 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months (EC Eval 391973). Before station batteries are depleted, portable FLEX diesel generators, as detailed in the response to Order EA-12-049, will be credited to charge the station batteries and maintain DC bus voltage after approximately 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months .

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

Ref: EA-13-109 Section 1.2.8, 1.2.9 / NEI 13-02 Section 2.5, 4.2.2, 4.2.4, 6.1.2 The same support functions that are used in the BDBEE scenario would be used for severe accident venting with the exception that the FLEX DG is not available. A suitable location for connecting test instruments for DW pressure and suppression pool water level will be required to monitor these parameters after approximately 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months .

The ROS (the location of the HCVS DC power source, Argon purge, and motive force) will be evaluated to confirm accessibility under severe accident conditions.

Details:

Provide a brief description of Procedures / Guidelines:

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

The operation of the HCVS will be governed the same for SA conditions as for BDBEE conditions. Existing guidance in the SAMG directs the plant staff to consider changes in radiological conditions in a severe accident.

Identify modifications."

List modifications and describe how they support the HCVS Actions.

The same as for BDBEE Venting Part 2 with the exception that a suitable location for connecting test instruments for DW pressure and suppression pool water level will be required.

Page 26 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for WW Vent - Support Equipment Functions Key Support Equipment Parameters:

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

The same as for BDBEE Venting Part 2.

Notes: None Page 27 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 2: Boundary Conditions for WW Vent - Venting Portable Equipment Deployment Provide a general description of the venting actions using portableequipment including modifications that are proposed to maintain and/or support safety functions.

Ref: EA-13-109 Section 3.1 / NEI 13-02 Section 6.1.2, D.1.3.1 Deployment pathways developed 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.

Before the end of the initial 24-hour period, replenishment of the HCVS dedicated DC power, Argon purge gas, and motive power (pressurized gas) will occur at the ROS. The selection of the ROS location will take into account the SA temperature and radiation condition to ensure access to the ROS is maintained. The design will allow replenishment with minimal actions.

Details:

Provide a brief description of Procedures / Guidelines:

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

The portable equipment that must be deployed for HCVS operation is limited to the FLEX DG that is credited for maintaining power to the containment instrumentation following Station battery depletion.

Under non-SA conditions, operation of the FLEX DG is the same as for compliance with Order EA-12-049; thus, it is acceptable without further evaluation.

Under SA conditions, radiological conditions will impede deployment of the FLEX DG. Consequently, procedures will be developed to install test instruments to monitor DW pressure and suppression pool water level per Engineering Change (EC) process.

Strategy Modifications Protection of connections Per compliance with Order EA- N/A Per compliance with Order EA- 12-049 12-049 (FLEX) (FLEX)

Notes: None Page 28 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 General Licensees that use Option B.] of EA 1 09 (SA Capable DW Vent without SA WA) must develop their own QIP.

This template does not provide guidancefor that option.

Licensees using Option B.2 of EA-13-109 (SAWA and SAWM or 545°FSADW Vent (SADV) with SAWA) may use this templ ate for their OIP submittal. Both SA WM and SADV require the use of SA WA and may not be done independently. The HCVS actions uneter Part 2 apply to all of the following:

This Part is divided into the following sections:

3.1: Severe Accident Water Addition (SA WA) 3.1.A: Severe Accident Water Management (SA WM) 3.1.B: Severe Accident DW Vent (545 deg F)

Provide a sequence of events and identify any time constraint required for success including the basis for the time constraint.

SA WA and SA WM or"SADV Actions supporting SA conditions that have a time constraint to be successful should be identified with a technical basis and ajustificationprovided 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 hour9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months sfrom the onset of the loss of all injection sources.

Electrical generatorssatisfying the requirements of EA-12-049 may be creditedfor powering components and instrumentationneeded to establish a flow path.

Time Sensitive Actions (TSAs) for the purpose of SAWA are those actions needed to transport, connect and startportable 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 drnywell. Actions needed to establishpower to SA WA instrumentation should also be included as TSAs.

Ref: NET 13-02 Section 6.1.1.7.4.1,1.1.4, 1.1.5 The operation of the HCVS using SAWA and SAWMvISADV 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. In addition, HCVS valve operation, as required by EA-13-109 Requirement 1.2.5, may occur at the ROS on the 561 foot elevation of the Turbine Building.

Timelines (see attachments 2.1 .A for SAWAISAWM) were developed to identify required operator response times and actions. The timelines are an expansion of Attachment 2A and begin either as core damage occurs (SAWA) or after initial SAWA injection is established and as flowrate is adjusted for option B.2 (SAWM). The timelines do not assume the core is ex-vessel and the actions taken are appropriate for both in-vessel and ex-vessel core damage conditions.

Page 29 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 Part 3.1: Boundary Conditions for SAWA Table 3.1 - SAWA Manual Actions (Dresden non-flood scenario; flood scenario is less time limiting since there is greater than 24-hour flood warning, equipment can be fully deployed before flood, and plant will be shutdown and in partial cooldown to Mode 4)

Primary Action Primary Location!/Component Notes

1. Establish HCVS capability in U MCR or ROS. U Applicable to SAWA/SAWM accordance with Part 2 of this strategy.

OIP.

2. Connect SAWA pump discharge U Reactor building 517' elevation U Perform reactor building to injection piping. (ground level) hard pipe portions of deployment first.

connection to Low Pressure Coolant Injection (LPCI) Line.

U Manually open motor operated valve (MOV) 2(3)-1501-22A(B).

The second MOV 2(3)-1501-21A(B) is normally open).

3. Connect SAWA pump to water U At Ultimate Heat Sink (UHS) U* Consist of a Diesel Driven source, near intake structure, submersible pump discharging to a diesel driven SAWA Booster pump; with hoses.

4. Install test equipment to allow U MCR U Required when Station batteries monitoring of DW pressure and are depleted.

suppression pool water level.

5. Inject to RPV using SAWA U Flow control is by a manual U Initial SAWA flow rate is 421 pump (diesel). valve at the SAWA Booster gpm.

pump.

6. Monitor SAWA indications. U Flow indication at SAWA U Pump flow.

Pumps' location(s).

7. Use SAWM to maintain U TBD U Monitor DW pressure and availability of the WW vent (Pail Suppression Pool level.

3.1 .A). U Control SAWA flow at valve located on the diesel driven pump to reduce flow to 85

- ~ gpm.-

Discussion of timeline SAWA identified items

HCVS operations are discussed under Phase 1 of EA-13-109 (Part 2 of this OIP).

U 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. (HC VS-FAQ- 12)

Page 30 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2

6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months - Install test equipment for monitoring DW pressure and suppression pool water level. All other actions required are assumed to be in-line with the FLEX timeline submitted in accordance with the EA 049 requirements.

Less than 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months - 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.

Determine operating requirementsfor 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 I NET 13-02 Section 1.1.6, 1.1.4.4 It is anticipated that SAWA 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=0).

The SAWA flow path includes methods to minimize exposure of personnel to radioactive liquids I gases and potentially flammable conditions by inclusion of backflow prevention. The SAWA pump check valve is integral with the pump skid and will close and prevent leakage when the SAWA pump is secured. LPCI injection mode has installed ECCS check valve 2(3)-1501-25A(B) qualified for accident scenarios to prevent reverse flow from the RPV.

Table 3.2 - SAWA Manual Actions Timeline Time Action Notes T<I hour U Connect SAWA hose in Reactor U No evaluation required for Building (Step 2 of Table 3.1). actions inside Reactor U Open MOV 2(3)-1501-22A(B). Building.

U Core damage for Dresden is assumed to start at 1.9 hours1.041667e-4 days 0.0025 hours 1.488095e-5 weeks 3.4245e-6 months .

(MAAP Case 8).

T-l-~7* hours U Complete actions started at T<l hour U Evaluate core gap and early in (Step 2 of Table 3.1). vessel release impact to reactor

The assumed times of T=1 hr to U Connect SAWA pump to water supply building access for SAWA T=8 hrs to establish the bounds of at intake structure (Step 3 of Table 3.1). actions. It is assumed that applicability of radiological evaluations bave been reduced to

Install test equipment to monitor DW Reactor Building access is T=1 hr to T=7 hrs in order to Pressure and Suppression pool water limited due to the source term provide sufficient margin to inform level (Step 4 of Table 3.1). at this time unless otherwise operator action feasibility U Establish flow of at least 421 gpm to the noted. (Refer to HCVS-FAQ-evaluations and will be further RPV using SAWA systems. Begin 12 for actions in T=l-8 hour yemrenyrspne inome injection (Step 5 of Table 3.1). timeframe.

Page 31 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 dose assessment activities during an actual event. This accounts for the one hr gap between 7 and 8 hrs in this time line.

T<8-1 2 hours2.314815e-5 days 5.555556e-4 hours 3.306878e-6 weeks 7.61e-7 months U Monitor and Maintain SAWA flow at U SAWA flow must commence 421 GPM for four hours Steps 5 & 6 of at T=8 hours but should be Table 3.1). done as soon as motive force is available.

T_<12 hours U Proceed to SAWM actions per Part U SAWA flow may be reduced 3.1.A (Step 7 of Table 3.]). to 85 GPM at four hours

_____________________following SAWA initiation.

~~Greater Than 24 Hour coping Detail

Provide a general description of the SA WA actionsfor greater than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 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 4.2.2.4.1.3.1,1I.1.4 SAWA Operation is the same for the full period of sustained operation. If SAWM is employed, flow rates will be directed to preserve the availability of the HCVS wetwell vent (see 3.1 .A).

" : ' ~~~DetailS: ...

Details of Design Characteristics/Performance Specifications SA WA shall be capable of providing an RPV injection rate of 500 gpm within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months of a loss of all RPV injection following an ELAP/Severe Accident. SA WA shall meet the design characteristicsof the HCVS with the exception of the dedicated 24 hour2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months power source. Hydrogen mitigation is provided by backflow preventionfor 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/Controls/Instrumentation Dresden has not performed a site specific evaluation to justify the use of a lower site unique initial SAWA flow rate. Consequently, Dresden will assume an initial flow rate of 421 gpm. This is based on the Industry generic value of 500 gpm multiplied by (Dresden rated power (2957 MWt)/Rated power for the generic plant (3514 MWt, NEI 13-02, 4.1.1.2.3). This initial flow rate will be established within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months of the loss of all RPV injection following an ELAP/Severe Accident and will be maintained for four hours before reduction to the Wetwell vent preservation flow rate.

The locations of the SAWA equipment and controls, as well as ingress and egress paths will be evaluated for the expected severe accident conditions (temperature, humidity, radiation) for the Sustained Operating period.

Equipment will be evaluated to remain operational throughout the Sustained Operating period. Personnel exposure and temperature / humidity conditions for operation of SAWA equipment will not exceed the limits for ERG dose and plant safety guidelines for temperature and humidity.

The flow path will be suction at the intake structure for the plant Ultimate Heat Sink (UHS) through the submersible pump and a downstream SAWA Booster pump. A valve manifold at the discharge of SAWA Booster pump will include valves with throttle capability and separate lines for Dresden Unit 2 RPV and Dresden Unit 3 RPV. This valve manifold will also provide minimum flow and freeze protection for the pump. This pump and valve manifold will be in a suitable location to allow access under severe accident conditions.

Page 32 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 From this valve manifold, hoses will be routed to the permanent SAWA connection point located in the Reactor Building 517' elevation. The connection at the Reactor Building location is on a LPCI line to the RPV. This connection point includes one manual valve, which will be opened and kept open. In addition, it requires locally manually opening motor operated valve (MOV) 2(3)-1501-22A(B) on the LPCI line. The second MOV (2(3)-1501-21A(B)) is normally open. The actions at the Reactor Building will be done within the first hour of the event prior to severe accident conditions occurring. Backflow in the LPCI line is prevented by an existing LPCI check valve 2(3)- 1501 -25A(B).

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 valve manifold that also contains the SAWA flow indication. Communication will be established between the MCR and the SAWA flow control location.

Containment instrumentation required for SAWA will be monitored through testing instruments powered from batteries (e.g., 9 VDC).

The Intake structure is a significant distance from the discharge of the HCVS pipe with substantial structural shielding between the HCVS pipe and the pump deployment location. Pump refueling will also be accomplished from the EDG fuel oil tanks as described in the EA-12-049 compliance documents. See mechanical and electrical sketches in attachments, plant layout sketches in the assumptions part and a list of actions elsewhere in this part.

Evaluations of actions outside the Reactor Building for projected SA conditions (radiation ! temperature) indicate that personnel can complete the initial and support activities without exceeding the ERG-allowable dose for equipment operation or site safety standards (reference HCVS-WP-02, Plant Specific Dose Analysis for the Venting of Containment during SA Conditions). Evaluation of actions inside the Reactor Building for projected SA conditions (radiation/temperature) will be performed to determine that personnel can complete the initial and support activities without exceeding the ERG-allowable dose for equipment operation or site safety standards (reference HCVS-FAQ- 12).

Electrical equipment and instrumentation will be powered from the power sources noted in the table below with portable generators to maintain battery capacities during the Sustained Operating period.

Parameter Instrument Location Power Source / Notes DW Pressure* 2(3)-1640-11A(B) MCR Hand held test equipment RG 1.97 qualified Suppression Pool Level* 2(3)-1640-13A(B) MCR Hand held test equipment RG 1.97 qualified SAWA Flow* FLEX Pump Flow TBD Self-powered from indicator internal battery Valve indications and NA NA All valves are locally controls manually operated

minimum required instruments.

The instrumentation and equipment being used for SAWA and supporting equipment will be evaluated to perform Page 33 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 for the Sustained Operating period under the expected radiological and temperature conditions.

Equipment Protection SAWA installed components and connections external to protected buildings will be protected against the screened-in hazards of EA- 12-049 for the station. Portable equipment used for SAWA implementation will meet the protection requirements for storage in accordance with the criteria in NEI 12-06, Revision 0.

Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3 / NEI 13-02 Section 5.1.1, 5.4.6, 1.1.6 Provide a brief description of Procedures I Guidelines:

Confirm that procedure/guidanceexists 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

1. Connect SAWA pump discharge to LPCI piping.

Connect SAWA hose in Reactor Building (Step 2 of Table 3.1).

Open MOV 2(3)-150 1-22A(B).

2. Connect SAWA pump to intake using FSG*.

3. Power SAWAIHCVS components using FSG.

4. Start SAWA pump to establish SAWA flow.

5. Adjust SAWA flow at valve manifold and using SAWA flow indication to establish and maintain required flow.

Where an FSG (FLEX Support Guidelines) is referenced, it is yet to be determined if new guidance needs to be developed or if it will be the same FSG reference with the same steps used for FLEX.

Identify modifications:

List modifications and describe how they support the SA WA Actions.

Ref: EA-13-109 Attachment 2, Section B.2.2, / NET 13-02 Section 4.2.4.4, 7.2.1.8, Appendix I The list of modifications, below, is limited to those required to upgrade EA-12-049 FLEX equipment to meet EA-13-109 Phase 2 SAWA requirements.

Electrical Modifications - TBD Mechanical Modifications - TBD Instrument Modifications - SAWA flow instrument (others TBD)

Component Qualifications:

State the qualification usedfor equipment supporting SA WA Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3 / NEI 13-02 Section 1.1.6 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 Rev 0. SAWA components are not required to meet NEI 13-02, Table 2-1 design Page 34 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 conditions.

Notes:

None Part 3.1 .A: Boundary Conditions for SAWAISAWM

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 justificationprovided 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 periodsfor the maintaining SA WM actions such that the W4W vent remains available to remove decay heatfrom the containment:

SAWM can be maintainedfor >7 days without the need for a dmywell vent to maintainpressure below PCPL or containment design pressure, whichever is lower.

o Under this approach, no detail concerningplant modifications or procedures is necessam*y with respect to how alternatecontainment heat removal will be provided.

SAWM can be maintainedfor at least 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months , but less than 7 days before DWpressure reaches PCPL or design pressure, whichever is lower.

o Under this approach, a functional descriptionis required of how alternate containment heat removal might be established before DWpressure reaches PCPL or design pressure whichever is lower~. Under this approach, physical plant mnodifications and detailedprocedures are not necessary, but written descriptions of possible app roachesfor achieving alternate containment heat removal and pressure control will be provided.

SAWM can be maintainedfor <72 hours SAWM strategy can be implemented but for less than 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months before DW pressure reaches PCPL or design pressure whichever is lower.

o Under this approach, a functional description is required of how alternate containment heat remo~val might be established before DWpressure reaches PC'PL or design pressure whichever is lower. Under this approach,physical plant mnodifications and detailedprocedures are required to be implemented to insure achieving alternate containment heat removal and pressure control will be providedfor the sustained operatingperiod.

Ref: NEI 13-02 Appendix C.7 SAWM can be maintained for >7 days without the need for a drywell vent to maintain pressure below PCPL.

Basis for SAWM time frame... .. . "

SAWM can be maintained >7 days:

Dresden has not performed a site specific evaluation to justify the use of a lower site unique initial SAWA flow rate. Consequently, Dresden will assume an initial flow rate of 421 GPM. This is based on the Industry generic value of 500 gpm multiplied by (Dresden rated power/Rated power for the generic plant).

This initial flow rate will be established within 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months of the loss of all RPV injection following an ELAP/Severe Accident and will be maintained for four hours before reduction to the Wetwell vent preservation flow rate of 85 gpm.

Page 35 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 Instrumentation relied upon for SAWM operations is Drywell Pressure, Suppression Pool level and SAWA flow.

Except for SAWA flow, SAWM instruments are initially powered by station batteries. After Station battery depletion, these parameters will be monitored by portable test equipment using small batteries that will be available for the Sustained Operation period (7 days). The SAWA flow instrument will be self-powered from an internal power supply capable of being replenished, if needed, through the Sustained Operation period. 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 (Ref. 9: C.7.l.4.2, C.8.3.1).

Suppression Pool level indication is maintained throughout the Sustained Operation period, so the HCVS remains in-service. The time to reach the level at which the WW vent must be secured is >7 days using SAWM flowrates (Ref. 9: C.6.3, C.7.1.4.3).

Procedures will be developed that control the Suppression Pool level, while ensuring the DW pressure indicates 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.) (Ref. 9: C.7.1.4.3) .1I.A shows the Sequence of Events Timeline for SAWA / SAWM. (Ref. 9: C.7. 1.4.4).

Table 3 ,1,B SAW M Manual Actions Primary Action Primary Location!/Component Notes

1. Lower SAWA injection rate to At the valve manifold on the e Control to maintain control Suppression Pool Level SAWA Booster pump. containment and WW and decay heat removal. parameters to ensure WW vent remains functional.

85 gpm minimum capability is maintained for greater than 7 days.

2. Control SAWMV flowrate for Containment Instrument monitoring

SAWM flowrate will be containment control/decay heat in MCR. monitored using the following removal, instruments:

SAWA flow at the valve manifold - SAWA Flow on the SAWA Booster pump. - Suppression Pool Level

- Drywell Pressure

SAWM flowrate will be controlled using the manual valve at the valve manifold.

3. Establish alternate decay heat Various locations. SAWM strategy can preserve the removal. wetwell vent path for >7 days.

4. Secure SAWA ! SAWM. At SAWA Pumps' location(s). When alternate decay heat removal is established.

SAWM Time Sensitive Actions,

Page 36 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 Time Sensitive SAWM Actions:

12 Hours - Initiate actions to maintain the Wetwell (WW) vent capability by lowering injection rate, while maintaining the cooling of the core debris (SAWM). Monitor SAWM critical parameters while ensuring the WW vent remains available.

SAWiV Severe Accident Operation Determine operating requirementsfor SA WM, 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 / NEI 13-02 Appendix C It is anticipated that SAWM will only be used in Severe Accident Events based on presumed failure of plant injection systems per direction by the plant SAMGs. Refer to Attachment 2.1 .D for SAWM SAMG language additions.

First 24 Hour Coping Detail Provide a general description of the SA WM actionsfor first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months using installed equipment including station modifications that are proposed.

Given the initial conditionsfor 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 B.2.2, B.2.3 I NEI 13-02 2.5, 4.2.2, Appendix C, Section C.7 SAWA will be established as described as stated 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 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months , the flow will be reduced while monitoring DW pressure and Suppression Pool level. SAWM flowrate can be lowered to maintain containment parameters and preserve the WW vent path. SAWM will be capable of injection for the period of Sustained Operation.

=

Greater Than 24 Hour Coping Detail Provide a general description of the SA WM actionsfor greater than 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months 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 B.2.2, B.2.3 / NEI 13-02 Section 4.2.2, Appendix C, Section C.7 SAWM can be maintained >7 days:

The SAWM flow strategy will be the same as the first 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months until 'alternate reliable containment heat removal and pressure control' is reestablished. SAWM flow strategy uses the SAWA flow path. No additional modifications are being made for SAWM.

t. Details:

Page 37 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 Details of Design Characteristics/Performance Specifications Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3 I NEI 13-0)2 Section Appendix C SAWM 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. SAWA will be capable of injection for the period of Sustained Operation.

Equipment Locations/Controls/Instrumentation Describe locationfor SA WM monitoring and control.

Ref: EA-13-109 Attachment 2, Section B.2.2, B.2.3 / NEI 13-02 Appendix C, Section C.8, Appendix I The SAWM control location is the same as the SAWA control location. Local indication of SAWM flow rate is provided at the valve manifold by installed flow instrument qualified to operate under the expected environmental conditions. The SAWA flow instrument is self-powered by an internal power supply. Communications will be established between the SAWM control location and the MCR.

Injection flowrate is controlled by FLEX manual valve located on the valve manifold.

Suppression Pool level and DW pressure will be read with hand-held test instruments. These indications are used to control SAWM flowrate to the RPV.

Key Parameters:

List instrumentationcreditedfor the SA WM Actions.

Parameters used for SAWM are:

Drywell Pressure

Suppression Pool Level

SAWM Flowrate The Drywe11 pressure and Suppression Pool level instruments (2(3)-1640-l1A(B) and 2(3)-1640-13A(B)) are qualified to RG 1.97 and are the same as listed in Part 2 of this OIP. The SAWM flow instrumentation will be qualified for the environmental conditions expected when needed.

Notes:

None Page 38 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 3: Boundary Conditions for EA-13-109, Option 2 Part 3.1 .B: Boundary Conditions for SAWAISADV L",':" :/ .. " *"*Applicability of WW Design Considerations" .. ""

This section is not applicable to Dresden since Dresden is not using the option of SADV.

Table 3.1.C - SAD V Manual Actions-r ".... i. .. '

Timeline for SADVY_- * "

Severe Accident Venting - :

First 24 Hour Coping Detail " "-

Greater Than 24 Hour Coping Detail -:

Details: :: .. " ,'

Page 39 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 4: Progralmmatic Controls. Training. Drills and Maintenance Identify how the programmatic controls will be met.

Provide a description of the programmatic controls equipment protection, storage and deployment and equipment quality addressing the impact of temperature and environment.

Ref: EA-13-109 Section 3.1, 3.20 / NEI 13-02 Section 6.1.2, 6.1.3, 6.2 Program Controls:

The HCVS venting actions will include:

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

Routes for transporting portable equipment from storage location(s) to deployment areas will be developed as the response details are identified and finalized. The identified paths and deployment areas will be accessible when the HCVS is required to be functional including during Severe Accidents.

Procedures:

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

The HCVS and SAWA procedures will be developed and implemented following plant processes for initiating or revising procedures and contain the following details:

appropriate conditions and criteria for use of the HCVS and SAWA

when and how to place the HCVS and SAWA in operation

location of system components

instrumentation available

normal and backup power supplies

directions for sustained operation (Reference 9), including the storage and location of portable equipment

location of the remote control HCVS operating station (panel)

training on operating the portable equipment

testing of portable equipment Dresden credits Containment Accident Pressure (CAP) for ECCS pump NPSH.

Dresden will establish provisions for out-of-service requirements of the HCVS and compensatory measures that comply with the criteria from NEI 13-02 (Reference 9). The following provisions will be documented in the HCVS Program Document:

The provisions for out-of-service requirements for HCVS/SAWA are applicable in Modes 1, 2 and 3:

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

If for up to 30 days, the primary and alternate means of HCVS/SAWA operation are non-functional, Page 40 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 4: Programmatic Controls. Training. Drills and Maintenance 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 site corrective action program:

Determine the cause(s) of the non-functionality,

Establish the actions to be taken and the schedule for restoring the system to functional status and to prevent recurrence,

Initiate action to implement appropriate compensatory actions, and

Restore full HCVS functionality at the earliest opportunity not to exceed one full operating cycle.

Describe training plan List trainingplansfor affected 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/SAWA/SAWM 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/SAWAJSAWM 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 NE!113-06 andt 14-01 as codified in NTTF Recommendation 8 and 9 rulemaking.

The Licensee should demonstrate use in drills, tabletops, or exercisesfor HCVS operationas follows."

Hardened containment vent operationon normal power sources (no FLAP).

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

HCVS operationon backup power andfrom primar3,or alternatelocation during conditions of FLAP/loss of UHS with core damage. System use is for containment heat renwval AND containment pressure control with potentialfor combustible gases (Denonstrationmaty be in conjunction with SAG change).

Operationfor sustainedperiod with SAWA andt SAWM to provide decay heat removal and containment pressure control.

Ref: EA-13-109 Section 3.1 / NET 13-02 Section 6.1.3 Dresden will utilize the guidance provided in NEI 13-06 and 14-01 (References 10 and 11) for guidance related to drills, tabletops, or exercises for HCVS operation. In addition, Dresden will integrate these requirements with compliance to any rulemaking resulting from the NTTF Recommendations 8 and 9.

Page 41 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 4: Programmatic Controls. Training. Drills and Maintenance Describe maintenance plan:

o The maintenanceprogram should ensure that the HCVS/SAWA/SAWM equipment reliability is being achieved in a manner similar to that requiredfor FLEX equipment. Standardindustr~y templates (e.g.,

EPRI) and associatedbases may be developed to define specific maintenance and testing.

o Periodic testing and frequency should be determined based on equipment type and expected use (furtherdetails are provided in Part6 of this document).

o Testing should be done to verify design requirements and/or basis. The basis should be documented and deviationsfr'om vendor recommendations and applicable standards should be justifiled.

o Preventive maintenance should be determined based on equipment type and expected use. The basis should be documented and deviationsfrom vendor recommendations and applicable standardsshould be justified.

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

HCVS/SA WA permanent installed equipment should be maintainedin a manner that is consistent with assuring that it performs its function when required.

o HCVS/SAWA permanently installedequipment should be subject to maintenance and testing guidance provided to verify properfunction.

HCVS/SAWA non-installed equipment should be stored and maintainedin a manner that is consistent with assuring that it does not degrade over long periods of storage and that it is accessiblefor periodic maintenance andt testing.

Ref: EA-13-109 Section 1.2.13 / NEL 13-02 Section 5.4, 6.2 Dresden 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/SAWA/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.

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

Table 4-1: Testing and Inspection Requirements Description Frequency 2

Cycle the HCVS and installed SAWA valves' Once per every operating cycle and the interfacing system 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 Once per every other 4 operating cycle valves not used to maintain containment integrity during unit operations3.

Perform visual inspections and a walk down of Once per every other 4 operating cycle HCVS and installed SAWA components.

Page 42 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 4: Programmatic Controls. Training. Drills and Maintenance Functionally test the HCVS radiation monitors. Once per operating cycle Leak test the HCVS. (1) Prior to first declaring the system functional; (2) Once every three operating cycles thereafter; and (3) After restoration of any breach of system boundary within the buildings Validate the HCVS operating procedures by Once per every other operating cycle conducting an open/close test of the HCVS control function from its control location and ensuring that all HCVS vent path and interfacing system valves 5 move to their proper (intended) positions.

SNtrequired 2Atrtwo for HCVSsuccessful consecutive and SAWA check valves.the performances, test frequency may be reduced to a maximum of once per every other operating cycle.

3 o required if integrity of check function (open and closed) is demonstrated by other plant testing requirements.

4Atrtwo 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 part. 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:

PCIVs are required for containment integrity during Modes 1-3 and thus are excluded from EA-13-109 testing requirements. However, these PCI Vs are tested per by the Dresden design basis requirements to ensure valve operability and leakage tightness. Refer to generic assumption 109-4.

Page 43 of 69

Darese NucMlearPwrstatone Sceunis2en Part 5: Milestone Schedule Provide a milestone schedule. This schedule should include:

Modifications timeline

Procedure guidance development complete o HCVS Actions o Maintenance

Storage plan (reasonable protection)

Staffing analysis completion

Long term use equipment acquisition timeline

Training completion for the TICVS 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 D.1, D.3 / NET 13-02 Section 7.2.1 The following milestone schedule is provided. The dates are planning dates subject to change as design and implementation details are developed. Any changes to the following target dates will be reflected in the subsequent 6-month status reports.

Phase 1 Milestones:

Milestone Target Activity Status Comments Completion Date Hold preliminary/conceptual design meeting June 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 with Simultaneous with this submittal Phase 2 OIP U3 Design Engineering Complete December Started 2015 U3 Implementation Outage October Not Started 2016 U3 Maintenance and Operation Procedure Changes November Not Started Developed, Training Complete, & Walk-Through 2016 Demonstration/Functional Test U2 Design Engineering Complete September Not Started 2016 U2 Implementation Outage October Not Started 2017 U2 Maintenance and Operation Procedure Changes November Not Started Developed, Training Complete, & Walk-Through 2017 Demonstration/Functional Test Page 44 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Part 5: Milestone Schedule Submit Completion Report May 2018 Phase 2 Milestone Schedule: .. ..

Phase 2 Milestone Schedule Milestone Target Activity Status Comments Completion Date Submit Overall Integrated Implementation Plan Dec 2015 Complete with Simultaneous with this submittal Phase 1 Updated OWP Hold preliminary/conceptual design meeting Jan 2016 Expect to be engineering justification not modifications Submit 6 Month Status Report June 2016 Submit 6 Month Status Report Dec 2016 Submit 6 Month Status Report June 2017 Submit 6 Month Status Report Dec 2017 Submit 6 Month Status Report June 2018 Submit 6 Month Status Report Dec 2018 U2 Design Engineering Complete October 2016 Not Started Conceptual completed U2 Implementation Outage October 2017 Not Started Concurrent with Unit 2 Phase 1 U2 Maintenance and Operation Procedure Changes Developed, November Not Started SAMG Revision; Training Complete, & Walk-Trough Demonstration/Functional 2017 Concurrent with Unit 2 Test Phase 1 U3 Design Engineering Complete TBD Not Started U3 Implementation Outage October 2018 Not Started U3 Maintenance and Operation Procedure Changes Developed, November Not Started Training Complete, & Walk-Trough Demonstration/Functional 2018 Test Submit Completion Report May 2019 Notes:

None Page 45 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 1: HCVS/SAWA/SADV Portable Equipment BDBEE Severe Performance Maintenance/PM requirements List portable equipment Venting Accident Criteria Venting Nitrogen Cylinders X X 2 cylinders Check periodically for pressure, replace or replenish as needed (EC 400578, frequency specified by PM).

Argon Cylinders NA X 14 cylinders Check periodically for pressure, replace or replenish as needed.

FLEX DG X X 800 KW 480V Per response to EA-12-049.

FLEXISAWA Pump X X TBD Per vendor manual.

Portable Air Compressor (optional) X X TBD Per vendor manual.

Small Portable Generator X X TBD Per vendor manual.

DW Pressure Indicator. Hand Held Test Eqpt. X X TBD Per vendor manual Suppression Pool Level Indicator, Hand Held X X TBD Per vendor manual TestEquipment ____________ _________ __________________

Page 46 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 2A: Seqiuence of Events Timeline - HCVS IS& ICS secured t=12 hrs. Begin monitoring t= 24 hrs. Replenishment HPCI in due to shell side HCVS support systems. No of HCVS supports ELAP service inventory replenishment expected to be systems required.

Sequence 1 required until 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months . FLEX successful; Containment venting t=O tr2.0m t= 20m ICS Rc~stnred h ut not required due to t=] 18 HPCI assumed {SAWA ICS lost (Flex OIP)

No Injection Inlecti ion Lost Ilniection Level at TAF U/ Sequence 2 SRCIC Late Failure tz 23 hrs t* 24 hrs t= 3 *4 hrs Ref: SECY-12-0 157 Containment Ven ting (based on prevent ting exceeding PCPL) t, Core t=z 2't hrs t= 1{2hrs t= 168 hrs Sequence 3

3 RCIC Early Failure Ref: SOARCA t~l r t.* hrs SAWA Iniection LegendNot to Scale Adequate core cooling maintained Injection lost Increased shine at wetwell

-Post-RPV hreach Page 47 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 2.1 .A: Sequence of Events Timeline - SAWA / SAWM Sustained Operation period T=168 hours T=168 hours SAWA

)

'*, o','* *o Monitor containment parameters and conditions Time Action T=0 hours Start of FLAP T=8 hours Initiate SAWA flow at 421 gpm as soon as possible but no later than 8 hours9.259259e-5 days 0.00222 hours 1.322751e-5 weeks 3.044e-6 months T=12 hours Throttle SAWA flow to 85 gpm 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months after initiation of SAWA flow T=168 hours End of Sustained Operation Page 48 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents .1 .B Sequence of Events Timeline - SADV Not applicable to Dresden Page 49 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 2.1 .C: SAWA/SAWM Plant-Specific Datum Spill Over Pptrfl -2 503' Spillovertiejtt.t 8*

EDrywell L Floor EL 502'-4*

Wetwetl Level instrument range (0-30')

Wetwell 14 9' MAX LCO (TSG-2)

Total Torus Height 30f Torus Max [CO Level 14' - 9" (897500 gal)

Total Torus Voume -1919000 gal Freeboard volume in torus ~1021500 gal Rate of level rise 0 3 ft/hr @ 421 gpm Rate of level rise 00074 ft/hr @ 85 gpm Total water added (421 gpm for 4 hours4.62963e-5 days 0.00111 hours 6.613757e-6 weeks 1.522e-6 months and 85 gpm for 164 hours0.0019 days 0.0456 hours 2.71164e-4 weeks 6.2402e-5 months ~940000 gal Note: The above calculation does not consider mass loss rate by steam leaving the vernj, making the above estimates very conservative Page 50 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 2.1 .D: SAWM SAMG Approved Language The following general cautions, prioritiesand methods will be evaluatedfor plant specific applicability and incorporatedas appropriateinto the plant specific SAMGs using administrativeproceduresfor EPG/SAG change control process and implementation. SAMGs are symptom based guidelines and therefo~re address a wide variety of possible plant conditions and capabilitieswhile these changes are intended to accommodate those specific conditions assumed in Order EA 109. The changes will be made in a way that maintains the use of SAMGs in a s)ymptom based mode while at the same time addressing those conditions that may exist under extended loss of AC power (ELAP) conditions with significant core damage including ex-vessel core debris.

Actual Approved Language that will be incorporated into site SAMG*

Cautions:

SAddressing 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 I/II 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 Ib)llowing 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.

Page 51 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 3: Conceptual Sketches (Conceptual sketches, as necessary to indicate equipment which is installed or equipment hookups necessary for the strategies)

Sketch 1A Electrical Layout of System (preliminary)

Sketch 2A P&ID Layout of Wetweil Vent Sketch 2B Remote Operating Station Sketch 2C HCVS Layout Overview Sketch 3A P&ID Layout of SAWA Sketch 3B SAWA Site Layout Page 52 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Sketch 1A" Electrical Layout of System - HCYS t

.3 p

I V..),

I A. A. A, A.

A)

I I I

Page 53 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Sketch 2A: P&ID of Wetwell Vent TO SI~OC FC0 I-1601-13 II FC NC 2(3)-I1601-93 Rupture Disc I!

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Page 55 of 69

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Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Sketch 3A: P&ID Layout of SAWA To RPV 1501-25 1501-26 SAWA TORUS Booster Pump To Otther Divisiion.

of LF SAWA Flow Indicator LPCI Heat Exchanger 1 SAWA Flow Indicator To Other -... Li Unit SAWA TM.-...... Hose ".

UHS LPCI Pump UHS Submersible Pump Page 59 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Sketch 3B: SAWA Site Layout, Page 60 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 4: Failure Evaluation Table (per NEI 13-06)

Table 4A: Wetwell HCVS Failure Evaluation Table Functional Failure Failure Cause Alternate Action Failure with Alternate Mode Action Prevents

____________Containment Venting?

Fail to Vent (Open) Valves fail to open/close due to loss of normal None required - system SOVs utilize No on Demand AC power/DC batteries, dedicated 24-hour power supply. ___________

Valves fail to open/close due to depletion of Recharge system with provided portable No dedicated power supply. generators.____________

Valves fail to open/close due to complete loss Manually operate backup pneumatic No Of power supplies, supply/vent lines at ROS. ___________

Valves fail to open/close due to loss of normal No action needed. Valves are provided with No pneumatic supply. dedicated motive force capable of 24-hour

________ ____ ____ ____ ____ ____ operation._ _ _ _ _ _ _ _ _ _ _ _

Valves fail to open/close due to loss of Replace bottles as needed and/or recharge No alternate pneumatic supply (long term). with portable air compressors.____________

Valve fails to open/close due to SOV failure. Manually operate backup pneumatic No supply/vent lines at ROS.

Fail to stop venting Not credible as there is not a common mode N/A No (Close) on demand failure that would prevent the closure of at least 1 of the 2 valves needed for venting.

Both valves designed to fail shut.____________________

Spurious Opening Not credible as key-locked switch prevents N/A No mispositioning of the downstream HCVS PCIV and, additionally, DC power for the

_______________solenoid valve is normally de-energized. ____________________

Spurious Closure Valves fail to remain open due to depletion of Recharge system with provided portable No dedicated power supply, generators.

Valves fail to remain open due to complete Manually operate backup pneumatic No loss of power supplies, supply/vent lines at ROS.

Valves fail to remain open due to loss of Replace bottles as needed and/or recharge No alternate pneumatic supply (long term). with portable air compressors.

Page 61 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 5: References

1. Phase 1 Overall Integrated Plan in Response to June 6, 2013 Commission Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions (Order Number EA-13-109) RS-14-058

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

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

4. Order EA-13-109, Severe Accident Reliable Hardened Containment Vents, dated June 6, 2013

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

6. JLD-ISG-2013-02, Compliance with Order EA-13-109, Severe Accident Reliable Hardened Containment Vents, dated November 14, 2013

7. NRC Responses to Public Comments, Japan Lessons-Learned Project Directorate Interim Staff Guidance JLD-IS G-2012-02: Compliance with Order EA- 12-050, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents, ADAMS Accession No. ML12229A477, dated August 29, 2012

8. NEI 12-06, Diverse and Flexible Coping Strategies (FLEX) Implementation Guide, Revision 0, dated August 2012

9. NET 13-02, Industry Guidance for Compliance with Order EA-13-109, Revision 1, Dated April 2015

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

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

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

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

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

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

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

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

18. NEI HCVS-FAQ-07, Consideration of Release fr'om Spent Fuel Pool Anomalies

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

20. NEl FHCVS-AQ-09, Use of Toolbox Actions for Personnel

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

22. NEI White Paper HCVS-WP-02, HCVS Cyclic Operations Approach

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

24. Not Used

25. NURFG/CR-71 10, Rev. 1, State-of-the-Art Reactor Consequence Analysis Project, Volume 1: Peach Bottom Integrated Analysis

26. SECY-12-0157, Consideration of Additional Requirements for Containment Venting Systems for Boiling Water Reactors with Mark I and Mark II Containments, 11/26/12

27. Dresden UFSAR, Updated Safety Analysis Report.

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

29. FLEX MAAP Endorsement ML13190A201

30. Not Used

31. JLD-ISG-2015-01, Compliance with Phase 2 of Order EA-13-109, Order Modifying Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation under Severe Accident Conditions, dated April 2015

32. NEI White Paper HCVS-WP-04, Missile Evaluation for HCVS Components 30 Feet Above Grade, Revision 0, dated August 17, 2015

33. NEI HCVS-FAQ-10, Severe Accident Multiple Unit Response

34. NEl HCVS-FAQ-1 1, Plant Response During a Severe Accident

35. NEl HCVS-FAQ-12, Radiological Evaluations on Plant Actions Prior to HCVS Initial Use Page 62 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents

36. NEI HCVS-FAQ-13, Severe Accident Venting Actions Validation

37. MAAP Analysis to Support FLEX initial strategy, RM Document No. DR-MISC-043 Rev. 1 Page 63 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 6: Changes/Updates to this Overall Integrated Implementation Plan This Overall Integrated Plan has been updated in formnat and content to encompass both, Phase 1 and Phase 2 of Order EA-13-109. Any significant changes to this plan will be communicated to the NRC staff in the 6-Month Status Reports.

None Page 64 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Attachment 7: List of Overall Integrated Plan Open Items The following tables provide a summary of the open items documented in the Phase 1 Overall IntegratedPlan or the Interim Staff Evaluation (ISE) and the status of each item.

Phase 1 Open Items from OIP Status Open Items 1 Confirm that at least 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months battery coping time is available. Deleted. Closed to ISE Open Item number 1.

2 Determine actions to enable wetwell (WW) venting following a flooding around the torus. Deleted. Closed to ISE Open Item number 2.

3 Determine how Motive Power and/or HCVS Battery Power will be disabled during normal Deleted. Closed to ISE Open Item number 3.

operation.

4 Confirm that the Remote Operating Station (ROS) will be in an accessible area following a Deleted. Closed to ISE Open Item number 12.

Severe Accident (SA).

5 Confirm diameter on new common HCVS Piping. Deleted. Closed to ISE Open Item number 5.

6 Confirm suppression pool heat capacity. Deleted. Closed to ISE Open Item number 6.

7 Determine the approach for combustible gases. Deleted. Closed to ISE Open Item number 7.

8 Provide procedures for HCVS Operation. Deleted. Closed to ISE Open Item number 18.

9 Perform radiological evaluation for Phase ivent line impact on ERO response actions. Not Started Page 65 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Phase 1 Interim Staff Evaluation (ISE) Open Items Status Open Items 1Make available for NRC staff audit documentation confirming that Complete. EC 391973 Rev. 0 was completed to evaluate proposed battery load at least 6 hours6.944444e-5 days 0.00167 hours 9.920635e-6 weeks 2.283e-6 months battery coping time is available, shed to support FLEX events. The evaluation addressed both 125V and 250V battery systems. The evaluation identified that with the load shed, the 125V and 250V batteries will maintain acceptable capacity for a minimum of six (6) hours. This time supports the FLEX Strategy time line actions.

2 Make available for NRC staff audit documentation that confirms the Started.

ability to operate HCVS following flooding around the suppression pool.

3Make available for NRC staff audit documentation of a method to Started.

disable HCVS during normal operation to provide assurances against inadvertent operation that also minimizes actions to enable HCVS operation following an ELAP.

4 Make available for NRC staff audit the seismic and tornado missile Started.

________final design criteria for the HCVS stack.

5 Make available for NRC staff audit documentation of the licensee Started. Refer to the response to ISE open item 6.

design effort to confirm the diameter on the new common HCVS piping.

6Make available for NRC staff audit analyses demonstrating that Started. The required 1% vent capacity at the lower of PCPL or containment HCVS has the capacity to vent the steam/energy equivalent of one design pressure is being verified using RELAP which models the line size and percent of licensed/rated thermal power (unless a lower value is routing.

justified), and that the suppression pool and the HCVS together are In addition, MAAP analyses are being credited to verify that venting can be able to absorb and reject decay heat, such that following a reactor delayed for at least three (3) hours, which supports assuming a maximum decay shutdown from full power containment pressure is restored and then heat rate of 1%.

maintained below the primary containment design pressure and the primary containment pressure limit.

7Provide a description of the final design of the HCVS to address Started. Argon purge system design in progress.

hydrogen detonation and deflagration.

8Make available for NRC staff audit documentation of a Started.

determination of seismic adequacy for the ROS location.

Page 66 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents 9 Make available for NRC staff audit documentation that demonstrates Not Started.

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

10 Provide a description of the strategies for hydrogen control that Started. As described in the OIP, the HCVS torus vent path in each Dresden minimizes the potential for hydrogen ga~s migration and ingress into unit, starting at and including the downstream PCIV, will be a dedicated HCVS the reactor building or other buildings. flow path. There are no interconnected systems downstream of the downstream, dedicated HCVS PCIV. Interconnected systems are upstream of the downstream HCVS PCIV and are isolated by normally shut, fail shut PCIVs which, if open, would shut on an ELAP. There is no shared HCVS piping between the two units.

The vent path will rely on an Argon purge system to prevent line failure due to

____________________________________________hydrogen deflagration and detonation.

11 Provide descriptions of design details that minimize unintended Started. Refer to the response to ISE item 10. This eliminates the possibility of cross flow of vented fluids within a unit and between units on the cross flow of vented fluids within a unit and between the two units.

site.

12 Make available for NRC staff audit an evaluation of temperature and Started. Component location design in progress. The HCVS primary control radiological conditions to ensure that operating personnel can safely panel will be located in the Main Control Room (MCR).

access and operate controls and support equipment.

13 Make available for NRC staff audit the final sizing evaluation for Started.

HCVS batteries/battery charger including incorporation into FLEX DG loading calculation.

14 Make available for NRC staff audit documentation of the HCVS Started. Nitrogen system design in progress.

nitrogen pneumatic system design including sizing and location.

15 Make available for NRC staff audit descriptions of all Started. Instrument design in progress.

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

Page 67 of 69

Dresden Nuclear Power Station Units 2 and 3

________Overall Integrated Plan for Reliable Hardened Vents 16 Make available for NRC staff audit the descriptions of local Started. Component location design in progress. The HCVS primary control conditions (temperature, radiation and humidity) anticipated during panel will be located in the MCR.

ELAP and severe accident for the components (valves, instrumentation, sensors, transmitters, indicators, electronics, control devices, etc.) required for HCVS venting including confirmation that the components are capable of performing their functions during ELAP and severe accident conditions.

17 Make available for NRC staff audit documentation of an evaluation Started. The existing containment isolation valves are being evaluated for their verifying the existing containment isolation valves, relied upon for performance under wetwell venting conditions.

the HCVS, will open under the maximum expected differential pressure during BDBEE and severe accident wetwell venting.

18 Make available for NRC staff audit procedures for HCVS operation. Not Started Page 68 of 69

Dresden Nuclear Power Station Units 2 and 3 Overall Integrated Plan for Reliable Hardened Vents Phase 2 Open Items from OIP Comment Open Item 1 Determine SAWA flow control. Not started 2 Resolve location of the FLEX DG to mitigate radiological Not started consequences during severe accident conditions.

3 Validate time-line for Reactor Building hose connections does not Not started

________exceed 1 hour1.157407e-5 days 2.777778e-4 hours 1.653439e-6 weeks 3.805e-7 months . __________________________________

Page 69 of 69