Text

Sixth Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)
	ML16057A210
Person / Time
Site:	Dresden
Issue date:	02/26/2016
From:	Kaegi G; Exelon Generation Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	EA-12-049, RS-16-022
	Download: ML16057A210 (18)
	v • d • e

AdNOW Anow ExeLon Generation.,

Order No. EA-12-049 RS-16-022 February 26, 2016 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Dresden Nuclear Power Station, Unit 3 Renewed Facility Operating License No. DPR-25 NRC Docket No. 50-249

Subject:

Sixth Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)

References:

1. NRC Order Number EA-12-049, "Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," dated March 12, 2012

2. NRC Interim Staff Guidance JLD-ISG-2012-01, "Compliance with Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," Revision 0, dated August 29, 2012

3. NEI 12-06, "Diverse and Flexible Coping Strategies (FLEX) Implementation Guide,"

Revision 0, dated August 2012

4. Exelon Generation Company, LLC's Initial Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049), dated October 25, 2012

5. Exelon Generation Company, LLC Overall Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049), dated February 28, 2013 (RS-13-020)

6. Exelon Generation Company, LLC First Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA 049), dated August 28, 2013 (RS-13-119)

7. Exelon Generation Company, LLC Second Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA 049), dated February 28, 2014 (RS-14-010)

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 February 26, 2016 Page 2

8. Exelon Generation Company, LLC Third Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA 049), dated August 28, 2014 (RS-14-208)

9. Exelon Generation Company, LLC Fourth Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA 049), dated February 27, 2015 (RS-15-019) 10.Exelon Generation Company, LLC Fifth Six-Month Status Report in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA 049), dated August 28, 2015 (RS-15-210)

11. 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 Order EA-12-049 (Mitigation Strategies) (TAC Nos. MF1046 and MF1047), dated November 22, 2013

12. NRC letter to Exelon Generation Company, LLC, Dresden Nuclear Power Station, Units 2 and 3 Report for the Onsite Audit Regarding Implementation of Mitigating Strategies and Reliable Spent Fuel Pool Instrumentation Related to Orders EA-12-049 and EA-12-051 (TAC Nos. MF1 046, MF1 047, MF1 050, MF1 051), dated October 9, 2015 On March 12, 2012, 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 develop, implement, and maintain guidance and strategies to maintain or restore core cooling, containment, and spent fuel pool cooling capabilities in the event of a beyond-design-basis external event. Specific requirements are outlined in of Reference 1.

Reference 1 required submission of an initial status report 60 days following issuance of the final interim staff guidance (Reference 2) and an overall integrated plan pursuant to Section IV, Condition C. Reference 2 endorses industry guidance document NEI 12-06, Revision 0 (Reference 3) with clarifications and exceptions identified in Reference 2. Reference 4 provided the EGC initial status report regarding mitigation strategies. Reference 5 provided the Dresden Nuclear Power Station, Unit 3 overall integrated plan.

Reference 1 requires submission of a status report at six-month intervals following submittal of the overall integrated plan. Reference 3 provides direction regarding the content of the status reports. References 6, 7, 8, 9, and 10 provided the first, second, third, fourth, and fifth six-month status reports, respectively, pursuant to Section IV, Condition C.2, of Reference 1 for Dresden Station Unit 3. The purpose of this letter is to provide the sixth six-month status report pursuant to Section IV, Condition C.2, of Reference 1, that delineates progress made in implementing the requirements of Reference 1. The enclosed report provides an update of milestone accomplishments since the last status report, including any changes to the compliance method, schedule, or need for relief and the basis, if any. The enclosed report also addresses the NRC Interim Staff Evaluation Open and Confirmatory Items contained in Reference 11, and the NRC Audit Report open items contained in Reference 12.

U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-1 2-049 February 26, 2016 Page 3 This letter contains no new regulatory commitments. If you have any questions regarding this report, please contact David P. Helker at 610-765-5525.

I declare under penalty of perjury that the foregoing is true and correct. Executed on the 26th day of February 2016.

Respectfully submitted, 7t:~?p Glen T. Kaegi Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Enclosure:

1. Dresden Nuclear Power Station, Unit 3 Sixth Six-Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events cc: NRC Regional Administrator - Region III NRC Senior Resident Inspector Dresden Nuclear Power Station NRC Project Manager, NRR Dresden Nuclear Power Station Mr. John P. Boska, NRR/JLD/JOMB, NRC Illinois Emergency Management Agency - Division of Nuclear Safety

Enclosure Dresden Nuclear Power Station, Unit 3 Sixth Six-Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (14 pages)

Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 Enclosure Dresden Nuclear Power Station Unit 3 Sixth Six Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events 1 Introduction Dresden Nuclear Power Station, Units 2 and 3 (Dresden) developed an Overall Integrated Plan (Reference 1 in Section 8), documenting the diverse and flexible strategies (FLEX), in response to Reference 2. This enclosure provides an update of Unit 3 milestone accomplishments since submittal of the Overall Integrated Plan, including any changes to the compliance method, schedule, or need for relief/relaxation and the basis, if any.

With the report of Unit 2 full compliance (Reference 11) January 12, 2016, this six month update provides the status of Dresden Nuclear Power Station Unit 3 mitigating strategies implementation.

2 Milestone Accomplishments Modification and installation of remaining LPCI connections and associated piping have been completed.

3 Milestone Schedule Status The following provides an update to Attachment 2 of the Overall Integrated Plan. It provides the activity status of each item, and whether the expected completion date has changed. The dates are planning dates subject to change as design and implementation details are developed.

Original Target Activity Status Revised Target Completion Date { Include date changes in Completion Date this column}

Submit 60 Day Status Report Complete Submit Overall Integrated Complete Implementation Plan Contract with RRC Complete Submit 6 month updates August 2013 Update 1 Complete February 2014 Update 2 Complete August 2014 Update 3 Complete Page 1 of 14

Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 Original Target Activity Status Revised Target Completion Date Include date changes in Completion Date this column)

February 2015 Update 4 Complete August 2015 Update 5 Complete February 2016 Update 6 Complete with this submittal August 2016 Update 7 Not started January 2017 Submit Completion Report Not started Unit 2 Unit 3 Modification Development Oct 2014 Sept 2015

Phase I modifications Complete Oct 2014 Sept 2015

Phase 2 modifications Complete Oct 2014 Sept 2015

Phase 3 modifications Complete Unit 2 Unit 3 Modification Implementation Nov 2015 Nov 2016

Phase 1 modifications Complete Dec 2015 Nov 2015 Nov 2016

Phase 2 modifications Complete Dec 2015 Nov 2015 lNov 2016

Phase 3 modifications Complete Dec 2015 Procedure development Nov 2015 0 Strategy procedures Complete Nov 2015

Validate Strategy Complete Procedures (NEI 12-06, Sect. 11.4.3)

Nov 2015

Maintenance procedures Complete Jul 2015 Staffing analysis Complete Nov 2015 Storage Plan and construction Complete Nov 2015 FLEX equipment acquisition Complete Nov 2015 Training completion Complete Jul 2015 National SAFER Response Center Complete Operational Nov 2015 Unit 2 Implementation date Complete (Ref. 11)

Nov 2016 Unit 3 Implementation date Not Started Page 2 of 14

Dresden Nuclear Power Sixth Six Month of FLE February 26, 2016 1 Note(s):

1. Exelon will update the status of ongoing and future milestones in the Integrated Plan for Dresden Nuclear Power Station during a scheduled six (6) month update. This update will include any changes to the milestone schedule as submitted in the February 28, 2013 Integrated Plan.

4 Changes to Compliance Method Alternate approach for Hoses and cables Dresden will utilize an alternate method to the N+1 requirement applicable to hoses and cables as stated in Section 3.2.2 of NEI 12-06. This alternate method will be to provide additional hose or cable equivalent to 10% of the total length of each type/size of hose or cable necessary for the "N" capability. For each type/size of hose or cable needed for the "N" capability, at least 1 spare of the longest single section/length must be provided (Method 1). This method was presented in a paper from NEI to the NRC dated May 1, 2015 and endorsed by the NRC by letter dated May 18, 2015 (reference 9). Dresden has reviewed the NRC letter and provides the following additional information.

Each additional hose or cable section will be the same length and size as the N hose or cable. If replacement is needed, the replacement section will be a like for like and no additional engineering justification is required.

Alternate approach for N+1 equipment storage in commercial building.

Exelon proposes an alternate approach to NEI 12-06, Revision 0 for protection of FLEX equipment as stated in Section 5 (seismic,) Section 7 (severe storms with high winds), and Section 8 (impact of snow, ice and extreme cold). This alternate approach will be to store "N" sets of equipment in a fully robust building and the +1 set of equipment in a commercial building. For all hazards scoped in for the site, the FLEX equipment will be stored in a configuration such that no one external event can reasonably fail the site FLEX capability (N).

To ensure that no one external event will reasonably fail the site FLEX capability (N), Exelon will ensure that N equipment is protected in the robust building. To accomplish this, Exelon has developed procedures to address the unavailability allowance as stated in NEI 12-06, Revision 0, Section 11.5.3.,

(see Maintenance and Testing section below for further details). This section allows for a 90-day period of unavailability. If a piece of FLEX equipment stored in the robust building were to become or found to be unavailable, Exelon will impose a shorter allowed outage time of 45 days. For portable equipment that is expected to be unavailable for more than 45 days or expected to be unavailable during forecast site specific external events, actions will be initiated within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months of this determination to restore the site FLEX capability (N) in the robust storage location and implement compensatory measures (e.g., move the

+1 piece of equipment into the robust building) within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months where the total unavailability time is not to exceed 45 days. Once the site FLEX capability (N) is restored in the robust storage location, Exelon will enter the 90-day allowed out of service time for the unavailable piece of equipment with an entry date and time from the discovery date and time.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 MAINTENANCE AND TESTING

1. The unavailability of equipment and applicable connections that directly performs a FLEX mitigation strategy for core, containment, and SFP should be managed such that risk to mitigating strategy capability is minimized.

a. The unavailability of plant equipment is controlled by existing plant processes such as the Technical Specifications. When plant equipment which supports FLEX strategies becomes unavailable, then the FLEX strategy affected by this unavailability does not need to be maintained during the unavailability.

b. The required FLEX equipment may be unavailable for 90 days provided that the site FLEX capability (N) is met. If the site FLEX (N) capability is met but not protected for all of the site's applicable hazards, then the allowed unavailability is reduced to 45 days.'

c. If FLEX equipment is likely to be unavailable during forecast site specific external events (e.g., hurricane), appropriate compensatory measures should be taken to restore equivalent capability in advance of the event.

d. The duration of FLEX equipment unavailability, discussed above, does not constitute a loss of reasonable protection from a diverse storage location protection strategy perspective.

e. If FLEX equipment or connections become unavailable such that the site FLEX capability (N) is not maintained, initiate actions within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months to restore the site FLEX capability (N) and implement compensatory measures (e.g., use of alternate suitable equipment or supplemental personnel) within 72 hours8.333333e-4 days 0.02 hours 1.190476e-4 weeks 2.7396e-5 months .

f. If FLEX equipment or connections to permanent plant equipment required for FLEX strategies are unavailable for greater than 45/90 days, restore the FLEX capability or implement compensatory measures (e.g., use of alternate suitable equipment or supplemental personnel) prior to exceedance of the 45/90 days.

For Section 5, seismic hazard, Exelon will also incorporate these actions:

1. Large portable FLEX equipment such as pumps and power supplies should be secured as appropriate to protect them during a seismic event (i.e., Safe Shutdown Earthquake (SSE) level).

2. Stored equipment and structures will be evaluated and protected from seismic interactions to ensure that unsecured and/or non-seismic components do not damage the equipment.

For Section 7, severe storms with high winds, Exelon will also incorporate this action:

For a 2-unit site, N+1 set(s) of on-site FLEX equipment are required. The plant screens in per Sections 5 through 9 for seismic, flooding, wind (tornado), snow, ice and extreme cold, and high temperatures.

1 The spare FLEX equipment is not required for the FLEX capability to be met. The allowance of 90-day unavailability is based on a normal plant work cycle of 12 weeks. In cases where the remaining N equipment is not fully protected for the applicable site hazards, the unavailability allowance is reduced to 45 days to match a 6 week short cycle work period. Aligning the unavailability to the site work management program is important to keep maintenance of spare FLEX equipment from inappropriately superseding other more risk-significant work activities.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 o To meet Section 7.3.1.1.a, either of the following are acceptable:

o All sets (N+I) in a structure(s) that meets the plant's design basis for high wind hazards, or o N set(s) N in a structure(s) that meets the plant's design basis for high wind hazards and one set (+I) stored in a location not protected for a high wind hazard.

For Section 8, impact of snow, ice and extreme cold, Exelon will also incorporate this action:

Storage of FLEX equipment should account for the fact that the equipment will need to function in a timely manner. The equipment should be maintained at a temperature within a range to ensure its likely function when called upon. For example, by storage in a heated enclosure or by direct heating (e.g., jacket water, battery, engine block heater, etc.).

Exelon will meet all of the requirements in NEI 12-06, Revision 0 for Section 6.2.3.1 for external flood hazard and Section 9.3.1 for impact of high temperatures.

Alternate approach for FLEX valve manifold.

Water from the Suppression Pool of both units is used to accomplish the Phase 2 core cooling, containment heat removal (via isolation condenser shell side make-up), and SFP cooling strategies. The water is supplied to the plant using an electric driven pump to supply the LPCI discharge header. The LPCI discharge header is connected to a FLEX manifold in the reactor building with hose connection points. The FLEX manifold distributes water to the various locations; isolation condenser make-up, spent fuel pool make-up, SBLC tank make-up and reactor water make-up. The FLEX Manifold includes several connection points that can be used for the various strategies.

The use of the FLEX manifold is an alternate approach to meeting the order. This manifold is an alternative to the conditions endorsed by the NRC in NEI 12-06, Revision 0. This is a robust design and will withstand the BDBEE hazards scoped in for Dresden Station.

The FLEX manifold is located on the 545' elevation of the Reactor Building. The Reactor Building is a Seismic Category 1 building and protected from tornadoes and missiles; thus the manifold is also projected from those external hazards. Additionally, the FLEX manifold will be protected from extreme cold and heat in the same manner as all other equipment located in the Reactor Building. The Probable Maximum Flood (PMF) height for Dresden is 525' elevation with 4' wave run-up (total of 529'); since the FLEX manifold piping taps in at approximately 517' level of the Reactor Building and runs up to the 545' level, the FLEX strategy is not protected from flooding. Dresden has developed a separate flood FLEX strategy that will use the fire system header.

The location of the FLEX manifold is physically separated from non-seismically supported components that could potentially damage the manifold by seismic interaction. Also, the manifold is securely anchored to the Reactor Building. Therefore, the FLEX manifold is reasonably protected from seismic hazards and is robust because the manifold won't be damaged by nearby non-seismically supported components.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 Given that the FLEX manifold is reasonably protected from all applicable external hazards with the exception of flood, is seismically robust, only contains manual valves and has multiple flow paths downstream of the manifold, the FLEX manifold at Dresden will be available to support core, containment, and spent fuel pool cooling water following a BDBEE.

There are additional flow paths available that are capable of providing makeup but at reduced flow rates.

The additional paths provide additional diversity in extreme cases. The additional paths include the use of flexible hoses directly off the LPCI riser FLEX connection to various locations. This would entail the use of "wye" connectors.

Alternate approach-for pre-staged FLEX pumps.

As described in the "Second Six Month Status Report for the Implementation of FLEX" (February 2014)

Dresden will be utilizing pre-staged electric driven pumps to support FLEX strategies. The use of the pre-staged pumps is an alternate approach to meeting the order. This approach is an alternative to the conditions endorsed by the NRC in NEI 12-06, Revision 0.

There are a total of 4 pumps. Two fulfill the "N" function and two fulfill the "N+l" function. The pumps are located in diverse locations inside the Reactor Building which is a robust structure. This is a robust design and will withstand the BDBEE hazards scoped in for Dresden Station.

Update of compliance for FLEX Generators during a flood event As described in the "Second Six Month Status Report for the Implementation of FLEX" (February 2014)

Dresden will be placing a portable 480 VAC diesel generator on the 2/3 Reactor Building Trackway roof to supply power for FLEX strategies during a flood event. This generator fulfills the "N" function for FLEX equipment requirements during a flood event.

As an update to this compliance, Dresden will also place an additional diesel generator on the Trackway roof. This generator fulfills the "N+1" function for FLEX equipment requirements during a flood event.

Update of compliance for new MAAP analysis. Case 12 now available.

In the "Third Six Month Status Report for the Implementation of FLEX" Dresden provided Attachment 4

-MAAP Justification for ELAP Analysis Acceptability. As part of the continuing development and design of FLEX strategies Dresden has performed additional MAAP analysis cases to reflect plant response to the integrated FLEX strategy. The original MAAP case results were communicated in the Third Six Month Status Report. The MAAP Justification for ELAP Analysis Acceptability has been updated to reflect the results of the additional MAAP case. The revised document is included as in Reference 13.

5 Need for Relief/Relaxation and Basis for the Relief/Relaxation Dresden Nuclear Power Station expects to comply with the order implementation date and no relief/relaxation is required at this time.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 6 Open Items from Overall Integrated Plan and Draft Safety Evaluation The following tables provide a summary of the open items documented in the Overall Integrated Plan or the Draft Safety Evaluation (SE) and the status of each item.

Section Reference Overall Integrated Plan Open Item Status Sequence of Events (page 5-6) The times to complete actions in the Complete Events Timeline are based on operating An integrated review judgment, conceptual designs, and was performed as the current supporting analyses. The final final step of the timeline has been time validated.

validation process to ensure adequate resources are available to accomplish a FLEX strategy as a whole.

Sequence of Events (page 5) Analysis of deviations between Exelon's Complete. See August engineering analyses and the analyses 2013 Update.

contained in BWROG Document NEDC-33771P, "GEH Evaluation of FLEX Implementation Guidelines and documentation of results on Att. 113, "NSSS Significant Reference Analysis Deviation Table." Planned to be completed and submitted with August 2013 Six Month Update.

Sequence of Events (page 8) Initial evaluations were used to determine Complete. See August the fuel pool timelines. Formal 2014 Update.

calculations will be performed to validate this information during development of the spent fuel pool cooling strategy detailed design.

Deployment Strategy (pages 8- Transportation routes will be developed Complete. See Interim

9) from the equipment storage area to the Staff Evaluation FLEX staging areas. An administrative Confirmatory Item program will be developed to ensure 3.1.2.2.A response.

pathways remain clear or compensatory actions will be implemented to ensure all strategies can be deployed during all modes of operation.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report U r the Implementation of February 26, 2016 Section Reference Overall Integrated Plan Open Item Status Programmatic Controls (pages An administrative program for FLEX to Complete. See August 9- establish responsibilities, and testing & 2015 Update.

10) maintenance requirements will be implemented.

Spent Fuel Pool Cooling Phase Complete an evaluation of the spent fuel Complete. See Interim 2 pool area for steam and condensation. Staff Evaluation Discussion (page 46) Confirmatory Item 3.2.2.A response.

Safety Functions Support Evaluate the habitability conditions for Complete. See Interim Phase 2 the Main Control Room and develop a Staff Evaluation Discussion (page 57) strategy to maintain habitability. Confirmatory Item 3.2.4.6.0 response.

Safety Functions Support Evaluate the habitability conditions for Complete. See Interim Phase 2 the Auxiliary Electric Equipment Room Staff Evaluation Discussion (page 57) (AEER) and develop a strategy to Confirmatory Item maintain habitability. 3.2.4.2.0 response.

Item Interim Staff Evaluation OPEN Item Status number 3.1.1.1.A Each section of the Integrated Plan Complete. See February 2014 Update.

describing storage protection from hazards makes reference to Section 11 rather than to the specific protection requirements described in NEI 12-06 for the applicable hazard; that is Section 6.2.3.1 for floods, Section 7.3.1 for wind, etc. As a result, the specific guidelines for each hazard are not addressed.

3.1.2.2. B The Plan is silent regarding loss of Complete. See February 2014 Update.

normal access to the Ultimate Heat Sink (UHS) due to flood hazard conditions, the need to provide electrical power for sump pumps, and whether or not flood barriers will be utilized.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 Item Interim Staff Evaluation OPEN Item Status number 3.2.4.8.A Updated information provided by the Complete. See August 2014 Update.

licensee as part of the 6-month update states that they are proposing to install a prestaged generator to supply all FLEX related loads for both units simultaneously for Phase 2 mitigating strategies. This appears to be an alternative approach for satisfying the Mitigating Strategies order. Insufficient information has been provided by the licensee in order to determine whether this provides an equivalent level of protection as would be provided through conformance with NEI 12-06.

3.1.1.2.A A postulated downstream dam failure Complete. See February 2014 Update.

from a seismic event is still being evaluated.

3.1.1.2.13 Plans for strategies did not address Complete. See August 2015 Update.

whether electrical power would be required to move or deploy FLEX equipment (e.g. to open a door from a storage location.)

3.1.1.3.A Development of a reference source for Complete. See August 2015 Update.

obtaining necessary instrument readings in the event of seismic damage to electrical equipment as described in NEI 12-06, Section 5.3.3, consideration 1.

3.1.1.3.13 Use of, or need for ac power to mitigate Complete. See February 2014 Update.

ground water intrusion was not addressed.

3.1.1.4.A Regarding off site resources, detailed Complete. See February 2015 Update.

plans for local staging areas and transport of FLEX equipment to overcome hazards are to be provided in 6-month update.

3.1.2.A Impact of persistence of flooding to Complete. See August 2015 Update.

staging of FLEX equipment not fully addressed.

3.1.2.2.A Administrative program and procedures Complete. See August 2015 Update.

for on-site FLEX equipment storage locations and transport routes not yet established.

3.1.2.3.A Administrative program and procedures Complete. See August 2015 Update.

related to implementation of mitigation strategies not yet developed.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLE February 26, 2016 1 item Interim Staff Evaluation OPEN Item Status number 3.1.4.2.A Equipment to clear ice and snow from Complete. See February 2014 and August haul pathways is not identified in plan. 2015 Updates.

3.1.5.2.A Procedures to assure equipment can be Complete. See August 2015 Update.

deployed in a high temperature context have not been developed. Specifically, address high temperature effects on storage locations (e.g. expansion of sheet metal, swollen seals, etc.)

3.1.5.3.A Procedures to address high temperature Complete. See August 2015 Update.

impacts on FLEX equipment not yet developed.

3.2.1. LA Need benchmarks to demonstrate Complete. See August 2014 Update.

Modular Accident Analysis Program MAAP 4 is the appropriate code for simulation of FLAP.

3.2. 1. 1.13 For MAAP 4, collapsed level must Complete. See August 2014 and August 2015 remain above Top of Active Fuel and Update.

cool down rate must meet technical specifications.

3.2.1. LC MAAP 4 use must be consistent with Complete. See August 2014 Update.

June 2013 position paper.

3.2. 1. 1.1) In using MAAP 4, the licensee must Complete. See August 2014 Update.

identify and justify the subset of key modeling parameters cited from Tables 4-1 through 4-6 of the "MAAP 4 Application Guidance, Desktop Reference for Using MAAP4 Software, Revision 2" (Electric Power Research Institute Report 1020236).

3.2.1.1.E The specific MAAP 4 analysis case Complete. See August 2014 and August 2015 that was used to validate the timing of Updates.

mitigating strategies in the integrated plan must be identified and should be available on the ePortal for NRC staff to view. Alternately, a comparable level of information may be included in the supplemental response.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 Item Interim Staff Evaluation OPEN Item Status number 3.2.1.3.A Outstanding Confirmatory Items Complete. See August 2015 Update.

regarding the use of the MAAP 4 analysis may impact the sequence of events timeline. Any changes to the MAAP 4 analysis results will need to be reviewed for impact on the sequence of events timeline. The licensee stated that the final timeline will be time validated once detailed designs are completed, procedures are developed, and the results will be provided in a future six (6) month update.

3.2.1.3.13 Sequence of Events timing for Complete. See August 2015 Update.

compensatory actions to control temperature rise in the Main Control Room not resolved.

3.2.1.4.A Detailed engineering analyses to Complete. See August 2015 Update.

confirm the ability of FLEX pumps to provide required flow and head capacities are not complete.

3.2.1.4.13 Analysis needs to be performed to Complete. See August 2015 Update.

validate that the plant modifications, selected equipment, and identified mitigating strategy can satisfy the safety function requirements of NEI 12-06. To be provided in a future six (6) month update.

3.2.1.6.A Whether or not backup compressed air Complete. See August 2014 Update.

for valve actuation is required, is contingent on the MAAP 4 analyses conclusions. The MAAP 4 conclusions will determine if containment venting is necessary.

3.2.2.A Final analysis of fuel pool area for Complete. See August 2015 Update.

steam and condensation impacts regarding access is not complete.

3.2.3A A There are outstanding issues regarding Complete. See August 2014 Update.

the acceptability of the MAAP 4 analysis. The potential for impact of MAAP 4 results on the containment heat removal strategy needs to be reviewed.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 Item Interim Staff Evaluation OPEN Item Status number 3.2.4.2.A A discussion is needed on the effects of Complete. See Reference 11.

extreme low temperatures (i.e.,

temperatures below those assumed in the sizing calculation for each battery) on each battery's capability to perform its function for the duration of the ELAP event.

3.2.4.2.B Procedure will be developed to address Complete. See Reference 11.

controlling battery room hydrogen concentration.

3.2.4.2.0 Evaluations to address loss of Complete. See Reference 11.

ventilation in the auxiliary equipment electric room and Battery Rooms are not complete.

3.2.4.2.D Insufficient information to address Complete. See August 2015 Update.

impact on elevated temperatures in areas critical to mitigation strategies.

For example, initial temperatures assumed in the analyses is not clear, critical components in pump rooms are not identified, etc. Detailed design information is needed.

3.2.4.4.A Provisions for portable lighting for area Complete. See August 2015 Update.

access not clear. More information required.

3.2.4.4.B Confirm upgrades to communication Complete. See August 2015 Update.

system that resulted from the licensee communications assessment. ADAMS Accession Nos. ML12306A199 and ML13056A135.

3.2.4.6.A Surface pyrometer temperature Complete. See August 2015 Update.

readings are required in the torus area.

The licensee needs to address habitability and access to the torus area.

3.2.4.6.B Final GOTHIC analysis for the HPCI Complete. See August 2015 Update.

room temperature rise is not complete.

3.2.4.6.0 Habitability of the control room should Complete. See August 2015 Update.

consider temperature limits of NUMARC 87-00 and MIL-STD-1472C.

3.2.4.8.B Detailed designs will identify Complete. See August 2015 Update.

comprehensive load lists to confirm conceptual load assumptions.

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016 Item Interim Staff Evaluation OPEN Item Status number 3.2.4.8.0 Insufficient information provided Complete. See February 2015 Update.

regarding FLEX diesel generators and the plant Class I E diesel generators isolation to prevent simultaneously supplying power to the same Class I E bus and regarding minimum bus voltages during the use of FLEX generators.

3.2.4.9.A The licensee stated in its 6-month Complete. See February 2015 Update.

update that a modification has been proposed to allow transfer of fuel oil from the 2/3 Emergency Diesel Generator main fuel oil storage tank to the area of the proposed FLEX diesel generators. Need to confirm that the modification is installed and supplies sufficient fuel.

3.2.4.9.13 Assessing and maintaining fuel oil Complete. See February 2015 and August quality for FLEX equipment use was 2015 Updates.

not addressed.

3.2.4.10.A Final analysis for battery operation Complete. See February 2015 Update.

with load shed not complete. Need detailed load profile for all mitigating strategies and a detailed discussion of loads that will be shed, how they will be shed, and what are the effects of the shed.

3.4.A Details not provided to demonstrate the Complete. See August 2015 Update.

minimum capabilities for offsite resources will be met per NEI 12-06, Section 12.2.

7 Potential Draft Safety Evaluation Impacts There are no potential impacts to the Draft Safety Evaluation identified at this time.

8 References The following references support the updates to the Overall Integrated Plan described in this enclosure.

1. Dresden Nuclear Power Station's Overall Integrated Plan in Response to March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (Order Number EA-12-049)," dated February 28, 2013 (RS 13 -020) (subsequently revised Aug 28, 2013)

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Dresden Nuclear Power Station, Unit 3 Sixth Six Month Status Report for the Implementation of FLEX February 26, 2016

2. NRC Order Number EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events," dated March 12, 2012

3. Dresden Nuclear Power Station Updated Final Safety Analysis Report, Revision 9

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

5. Dresden's First Six Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (August 2013), dated August 28, 2013 (RS-13-119)

6. Dresden's Second Six Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (February 2014), dated February 28, 2014 (RS-14-010)

7. Dresden's Third Six Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (August 2014), dated August 28, 2014 (RS-14-208)

8. Engineering Change 391973 Rev 000, Extend 125VDC and 250VDC Battery Coping Time with Load Shedding

9. NRC Letter endorsement of NEI Letter entitled "NEI Alternate Approach Hoses and Cables" (Agency wide Documents Access and Management System (ADAMS) Accession No. ML15126A135)

10. MAAP Justification for ELAP Analysis Acceptability Attachment I of Dresden's Fifth Six Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (August 2015),

dated August 28, 2015 (RS-15-210)

11. Letter from G.T. Kaegi (Exelon Generation Company, LLQ to Document Control Desk (NRC),

Report of Dresden Nuclear Power Station, Unit 2 Full Compliance with March 12, 2012 Commission Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design Basis External Events (Order EA-12-049), dated January 12, 2016

12. Dresden's Fourth Six Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (February 2015), dated February 27, 2015 (RS-15-019)

13. Dresden's Fifth Six Month Status Report for the Implementation of Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events (August 2015), dated August 28, 2015 (RS-15-210)

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