Text

Dresden, Units 2 and 3 - 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-12-049)
	ML14248A238
Person / Time
Site:	Dresden
Issue date:	08/28/2014
From:	Kaegi G T; Exelon Generation Co
To:	; Document Control Desk, Office of Nuclear Reactor Regulation
References
	EA-12-049, RS-14-208
	Download: ML14248A238 (36)
	v • d • e

sinw. Exelon Generation Order No. EA-12-049 RS-14-208 August 28, 2014 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:

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-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 August 28, 2014 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 Order EA-12-049 (Mitigation Strategies) (TAC Nos. MF1046 and MF1047), dated November 22, 2013 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 EGO 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 EGO initial status report regarding mitigation strategies. Reference 5 provided the Dresden Nuclear Power Station, Units 2 and 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 and 7 provided the first and second six-month status reports, respectively, pursuant to Section IV, Condition 0.2, of Reference 1 for Dresden Station. The purpose of this letter is to provide the third 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 8.

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 28 th day of August 2014.

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

Enclosure:

1. Dresden Nuclear Power Station, Units 2 and 3 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 U.S. Nuclear Regulatory Commission Integrated Plan Report to EA-12-049 August 28, 2014 Page 3 cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region III NRC Senior Resident Inspector - Dresden Nuclear Power Station, Units 2 and 3 NRC Project Manager, NRR - Dresden Nuclear Power Station, Units 2 and 3 Ms. Jessica A. Kratchman, NRR/JLD/PMB, NRC Mr. Jack R. Davis, NRR/DPR/MSD, NRC Mr. Eric E. Bowman, NRR/DPR/MSD, NRC Mr. Jeremy S. Bowen, NRR/DPR/MSD/MSPB, NRC Mr. Robert L. Dennig, NRR/DSS/SCVB, NRC Mr. John P. Boska, NRR/DPR/MSD/MSPB, NRC Illinois Emergency Management Agency - Division of Nuclear Safety Enclosure Dresden Nuclear Power Station, Units 2 and 3 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 (32 pages)

Enclosure 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 1 Introduction Dresden Nuclear Power Station (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 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.

2 Milestone Accomplishments Modification development started.

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

Revised Target Completion Date Submit 60 Day Status Report Complete Submit Overall Integrated Implementation Plan Complete Contract with National SAFER Response Center Complete Submit 6 month updates August 2013 Update 1 Complete February 2014 Update 2 Complete August 2014 Update 3 Complete with this submittal February 2015 Update 4 Not started August 2015 Update 5 Not started February 2016 Update 6 Not started Page 1 of 31 Dresden Nuclear Power Station's Third Six Month Status Report for the Implementation of FLEX 8/28/2014 Original Target Completion Date Activity Status {Include date changes in this column}

Revised Target Completion Date August 2016 Update 7 Not started Submit Completion Report Unit 2 Unit 3 Modification Development Oct 2014 Sept 2015

Phase 1 modifications Started Oct 2014 Sept 2015

Phase 2 modifications Started Oct 2014 Sept 2015

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

Phase 1 modifications Note 1 Nov 2015 Nov 2016

Phase 2 modifications Note 1 Nov 2015 Nov 2016

Phase 3 modifications Note 1 Procedure development Nov 2015

Strategy procedures Note 1 Nov 2015

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

Note 1 Nov 2015

Maintenance procedures Note 1 Jul 2015 Staffing analysis Note 1 Nov 2015 Storage Plan and construction Note 1 Nov 2015 FLEX equipment acquisition Note 1 Nov 2015 Training completion Note 1 Jul 2015 National SAFER Response Center Operational (will be a standard date from National SAFER Response Center)

Nov 2015 Unit 2 Implementation date Note 1 Nov 2016 Unit 3 Implementation date Note 1 Note(s): 1. Exelon will update the status of ongoing and future milestones in the Integrated Plan for DNPS during a scheduled six (6) month update. This update will include any changes to the milestone schedule as submitted in the February 28, 2014 Integrated Plan update.

Page 2 of 31 Dresden Nuclear Power Station's Third Six Month Status Report for the Implementation of FLEX 8/28/2014 4 Changes to Compliance Method An update call was held with members of the Nuclear Regulatory Commission on May 28, 2014 to review current design concepts. During design development activities occurring since the February 2014 6-Month Status Report the following minor changes to the Compliance Method have been identified. The changes identified below were discussed during the May 28, 2014 update call.

Power for FLEX required loads during non-flood events will be supplied from one pre-staged diesel generator located near the Reactor Building. The pre-staged diesel generator will be housed in a robust structure to provide protection for all events except flood. This diesel generator will be a trailer mounted unit capable of supplying power to all anticipated requirements for both Units at Dresden after the event.

The change in compliance is there is now one diesel generator and it is a pre-staged trailer mounted unit. The remainder of the electrical FLEX strategy remains unaffected.

Flood coping strategy employs a diesel driven portable FLEX pump. Because the flood event is precipitation based there is time to prepare. The pump will be placed on a floating platform inside the Unit 3 Turbine Building Trackway. This location places the pump and platform near a large roll-up door which allows for adequate ventilation and does not impact other flood event preparations. The pump suction source will be the Unit 3 Main Condenser Tube Pull Pit area which will be filled with flood waters entering the Turbine Building. Pump discharge will be routed through temporary hose to a proposed connection on the Fire Protection header located on elevation 545'. Isolation Condenser shell-side makeup can be supplied from the Fire Main through a permanently installed makeup valve. The Fire Main will also be used as a supply header for other hoses to supply makeup needs for RPV makeup and Spent Fuel Pool.

The change in compliance is the portable pump will be located in the Unit 3 Turbine Building and Fire Main piping will be used to transport water from the portable pump to the required loads The electrical strategy during a flood event is unchanged from the February 2014 6-Month Status Update Report.

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.

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 Events Timeline are based on operating judgment, conceptual designs, and current supporting analyses. The final timeline will be time validated once detailed designs are completed and procedures developed.

Not Started Page 3 of 31 Dresden Nuclear Power Station's Third Six Month Status Report for the Implementation of FLEX 8/28/2014 Section Reference Overall Integrated Plan Open Item Status Sequence of Events (page 5) Analysis of deviations between Exelon's engineering analyses and the analyses contained in BWROG Document NEDC-33771P, "GEH Evaluation of FLEX Implementation Guidelines and documentation of results on Att. 1B, "NSSS Significant Reference Analysis Deviation Table." Planned to be completed and submitted with August 2013 Six Month Update.

Completed. See August 2013 Update Sequence of Events (page 8) Initial evaluations were used to determine the fuel pool timelines. Formal calculations will be performed to validate this information during development of the spent fuel pool cooling strategy detailed detailed design.

Proposed Complete.

Engineering Change (EC) 31913, TIME TO BOIL CURVES -

DR-104-1001, Revision 2 has been completed.

The EC supports the timeline assumptions made using initial evaluations. The associate times are reflected in Attachment 1, Revised Estimated Sequence of Events Timeline.

Deployment Strategy (pages 8-9)

Transportation routes will be developed from the equipment storage area to the FLEX staging areas. An administrative program will be developed to ensure pathways remain clear or compensatory actions will be implemented to ensure all strategies can be deployed during all modes of operation.

Identification of storage areas and creation of the administrative program are open items.

See Interim Staff Evaluation Confirmatory Item 3.1.2.2.A response.

Programmatic Controls (pages 9-

10) An administrative program for FLEX to establish responsibilities, and testing &

maintenance requirements will be implemented.

Not Started Spent Fuel Pool Cooling Phase 2 Discussion (page 46)

Complete an evaluation of the spent fuel pool area for steam and condensation.

See Interim Staff Evaluation Confirmatory Item 3.2.2.A response.

Safety Functions Support Phase 2 Discussion (page 57)

Evaluate the habitability conditions for the Main Control Room and develop a strategy to maintain habitability.

See Interim Staff Evaluation Confirmatory Item 3.2.4.6.0 response.

Page 4 of 31 Dresden Nuclear Power Station's Third Six Month Status Report for the Implementation of FLEX 8/28/2014 Section Reference Overall Integrated Plan Open Item Status Safety Functions Support Phase 2 Discussion (page 57)

Evaluate the habitability conditions for the Auxiliary Electric Equipment Room (AEER) and develop a strategy to maintain habitability.

See Interim Staff Evaluation Confirmatory Item 3.2.4.2.0 response.

Item number Interim Staff Evaluation OPEN Item Status 3.1.1.1.A Each section of the Integrated Plan 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.

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

Completed. See February 2014 Update Page 5 of 31 Dresden Nuclear Power Station's Third Six Month Status Report for the Implementation of FLEX 8/28/2014 Item number Interim Staff Evaluation OPEN Item Status 3.2.4.8.A Updated information provided by the 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 NET 12-06.

Proposed Complete As described in Section 4, Changes to Compliance Method, the conceptual design has changed to utilize a trailer mounted generator unit pre-staged in a robust structure near the Reactor Building. Pre-staging in this manner allows timely implementation of the FLEX strategies by not requiring transport of the generator prior to use.

The generator is a portable (trailer mounted) unit that will be connected through the use of temporary cabling. The proposed design meets the requirements of NEI 12-06 Section 3.2.1.3.(7) and Section 3.2.2.(13).

Additionally NET 12-06 Section 3.2.2 states, "It is also acceptable to have a single resource that is sized to support the required functions for multiple units at a site (e.g., a single pump capable of all water supply functions for a dual unit site)." The proposed design utilizes a single generator sized to be capable of powering the required loads of both Units after a FLEX event.

The change to the proposed design meets NEI 12-06 requirements and therefore is not an alternative approach.

Page 6 of 31 Dresden Nuclear Power Station's Third Six Month Status Report for the Implementation of FLEX 8/28/2014 Item number Interim Staff Evaluation CONFIRMATORY Item Status 3.1.1.2.A A postulated downstream dam failure from a seismic event is still being evaluated.

Completed. See February 2014 Update 3.1.1.2.B Plans for strategies did not address whether electrical power would be required to move or deploy FLEX equipment (e.g. to open a door from a storage location.)

Not started 3.1.1.3.A Development of a reference source for obtaining necessary instrument readings in the event of seismic damage to electrical equipment as described in NET 12-06, Section 5.3.3, consideration 1.

Started 3.1.1.3.B Use of, or need for ac power to mitigate ground water intrusion was not addressed.

Completed. See February 2014 Update 3.1.1.4.A Regarding off site resources, detailed plans for local staging areas and transport of FLEX equipment to overcome hazards are to be provided in 6-month update.

Started 3.1.2.A Impact of persistence of flooding to staging of FLEX equipment not fully addressed.

Started 3.1.2.2.A Administrative program and procedures for on-site FLEX equipment storage locations and transport routes not yet established.

Started 3.1.2.3.A Administrative program and procedures related to implementation of mitigation strategies not yet developed.

Started 3.1.4.2.A Equipment to clear ice and snow from haul pathways is not identified in plan. Completed. See February 2014 Update 3.1.5.2.A Procedures to assure equipment can be 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.)

Not started 3.1.5.3.A Procedures to address high temperature impacts on FLEX equipment not yet developed.

Started Page 7 of 31 Dresden Nuclear Power Station's Third Six Month Status Report for the Implementation of FLEX 8/28/2014 Item number Interim Staff Evaluation CONFIRMATORY Item Status 3.2.1.1.A Need benchmarks to demonstrate Modular Accident Analysis Program (MAAP) 4 is the appropriate code for simulation of ELAP.

Proposed Complete.