RS-15-101, Request for Schedule Relaxation from NRC Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events.

Request for Schedule Relaxation from NRC Order EA-12-049, Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events.

ML15092A833
Person / Time
Site:	Limerick
Issue date:	04/02/2015
From:	Jim Barstow Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
EA-12-049, RS-15-101
Download: ML15092A833 (7)

Text

ti r1 Order No. EA-12-049 RS-15-101 April 2, 2015 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 Limerick Generating Station, Unit 2 Renewed Facility Operating License No. NPF-85 NRC Docket No. 50-353

Subject:

Request for Schedule Relaxation from NRC Order EA-12-049, "Order Modifying Licenses With Regard To Requirements For Mitigation Strategies For Beyond-Design-Basis External Events"

References:

1. NRC Order 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. Exelon Generation Company, LLC letter to USNRC, "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 EA-12-049)," dated February 28, 2013 (RS-13-022)

3. NRC Letter to Exelon Generation Company, LLC, Limerick Generating Station Units 1 and 2-Relaxation of Certain Schedule Requirements for Order EA-12-049, "Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design Basis External Events," dated April 15, 2014

4. NRC Order EA-13-109, "Order Modifying Licenses With Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," dated June 6, 2013 This letter transmits a request for schedule relaxation of the requirements contained in Nuclear Regulatory Commission ("NRC" or "Commission") Order EA-12-049. On March 12, 2012, the NRC 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. Reference 2 provides the Mitigating Strategies Overall Integrated Plan for Limerick Generating Station, Units 1 and 2. In Reference 3, the NRC granted relaxation of certain schedule requirements of Order EA-12-049 related to full containment wetwell venting capability until completion of the Spring 2017 refueling outage for Limerick Generating Station, Unit 2 consistent with the requirements of NRC Order EA-13-109 (Reference 4). Reference 3 identified that the equipment and modifications required to implement the mitigating strategies required by Order EA-12-049 were to be completed and available for use in accordance with the original implementation schedule requirements, except for the primary containment venting strategy.

U.S. Nuclear Regulatory Commission April 2, 2015 Page2 The purpose of this letter is to request additional schedule relaxation from NRC Order EA-12-049 for Limerick Generating Station, Unit 2 of 90 days following restart from the Li2R13 refueling outage (Spring 2015) to allow completion of construction of the FLEX Storage Robust Buildings. Additional time is required to complete construction of the FLEX Storage Robust Buildings that have been delayed due to extreme weather conditions and delays in the completion of the building design and permitting. Other FLEX equipment, modifications, and procedures required to implement the mitigating strategies required by Order EA-12-049, except for the primary containment venting strategy, will be completed and available for use in accordance with the implementation schedule requirements specified in the Order.

Section IV of NRC Order EA-12-049 (Reference 1) states that licensees proposing to deviate from requirements contained in NRC Order EA-12-049 may request that the Director, Office of Nuclear Reactor Regulation, relax those requirements.

In accordance with Section IV of NRC Order EA-12-049, EGC is requesting that the Director, Office of Nuclear Reactor Regulation, relax the requirement for completion of full implementation as prescribed in Section IV.A.2 of NRC Order EA-12-049 as described in the attachment to this letter.

EGC considers that, upon approval by the NRC, the alternative implementation dates regarding NRC Order EA-12-049 proposed in the attachment will constitute a condition of the NRC Order EA-12-049 for Limerick Generating Station, Unit 2. Therefore, there are no new regulatory commitments contained in this letter.

If you have any questions regarding this request, 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 2nd day of April 2015.

Respectfully submitted,

~~~

James Barstow Director - Licensing & Regulatory Affairs Exelon Generation Company, LLC

Attachment:

Request for Schedule Relaxation of NRC Order EA-12-049 Requirement IV.A.2 for Limerick Generating Station, Unit 2

U.S. Nuclear Regulatory Commission April 2, 2015 Page 3 cc: Director, Office of Nuclear Reactor Regulation NRC Regional Administrator - Region I NRC Senior Resident Inspector- Limerick Generating Station NRC Project Manager, NRR - Limerick Generating Station Ms. Jessica Kratchman, NRR/JLD/JPMB, NRC Mr. Jeremy Bowen, NRR/J,LD/MSPB, NRC Ms. Mandy K. Halter, NRR/JLD/JOMB, NRC Mr. John D. Hughey, NRR/JLD/JOMB, NRC Director, Bureau of Radiation Protection - Pennsylvania Department of Environmental Resources R. R. Janati, Chief, Division of Nuclear Safety, Pennsylvania Department of Environmental Protection, Bureau of Radiation Protection

ATTACHMENT REQUEST FOR SCHEDULE RELAXATION OF NRC ORDER EA-12-049 REQUIREMENT IV.A.2 FOR LIMERICK GENERATING STATION, UNIT 2 Relaxation Request:

Pursuant to the procedure specified in Section IV of Nuclear Regulatory Commission (NRC)

Order EA-12-049, "Order Modifying Licenses with Regard to Requirements for Mitigation Strategies for Beyond-Design-Basis External Events" (Reference 1), Exelon Generation Company, LLC (EGC) hereby submits a request for schedule relaxation (for Limerick Generating Station, Unit 2) from the Order requirements for completion of implementation currently required to be no later than two (2) refueling cycles after submittal of the overall integrated plan, as required in Condition C.1.a of the Order, or December 31, 2016, whichever occurs first. In Reference 3, the NRC previously granted relaxation of the Order requirement for full implementation until completion of the Spring 2017 refueling outage until the full containment wetwell venting capability required by Order EA-13-109 (Reference 4) is implemented. As stated in Reference 3, Limerick Generating Station, Unit 2 committed to complete installation of equipment and modifications required to implement the mitigating strategies required by Order EA-12-049 in accordance with the original implementation schedule requirements, except for the primary containment venting strategy.

Order Requirement from Which Relaxation is Requested:

NRC Order EA-12-049,Section IV.A.2 requires completion of full implementation of the Order requirements to be no later than two (2) refueling cycles after submittal of the overall integrated plan, as required by Condition C.1.a or December 31, 2016, whichever comes first. In accordance with the requirements of the Order, EGC submitted the Limerick Generating Station, Units 1 and 2, Mitigation Strategies Overall Integrated Plan (Reference 2) on February 28, 2013.

The Limerick Generating Station, Units 1 and 2, Mitigation Strategies Overall Integrated Plan milestone schedule identified the completion date for full implementation of NRC Order EA-12-049 as May 2015 for Unit 2, in order to satisfy the requirements of N RC Order EA-12-049.

In Reference 3, the NRC granted relaxation of certain schedule requirements of Order EA-12-049 related to full containment wetwell venting capability until completion of the Spring 2017 refueling outage for Limerick Generating Station, Unit 2 consistent with the requirements of NRC Order EA-13-109 (Reference 4). The schedule for implementation of full containment wetwell venting capability is not changed. Reference 3 identified that the equipment and modifications required to implement the mitigating strategies required by Order EA-12-049 were to be completed and available for use in accordance with the original implementation schedule requirements, except for the primary containment venting strategy.

As described in Reference 2, Limerick Generating Station has elected to build two FLEX Storage Robust Buildings. The first building is constructed of reinforced concrete approximately 40' wide x 7 5' long x 21' high and located inside the Protected Area. The second building is constructed of reinforced concrete approximately 60' wide x 90' long x 21' high and located outside the Protected Area. Limerick Generating Station, Unit 2 will be unable to demonstrate compliance to NRC Order EA-12-049 until such time that both FLEX

ATTACHMENT REQUEST FOR SCHEDULE RELAXATION OF NRC ORDER EA-12-049 REQUIREMENT IV.A.2 FOR LIMERICK GENERATING STATION, UNIT 2 Storage Robust Buildings are completed and the FLEX equipment required to support the mitigation strategies is stored in these buildings. The current schedule requirement for Limerick Generating Station, Unit 2 implementation of NRC Order EA-12-049, with the exception of the primary containment venting strategy, is prior to restart from the Li2R13 refuelhg outage in May 2015. The requested relaxation would defer the compliance schedule date of NRC Order EA-12-049, with the exception of the primary containment venting strategy, to no later than 90 days following restart from the Li2R13 refueling outage.

The requested relaxation would enable EGC to complete construction of both FLEX Storage Robust Buildings.

• At this time, EGC has procured portable equipment, drafted FLEX procedures, and completed all training. The portable equipment is currently being stored onsite. Remaining activities include implementing modifications scheduled during the upcoming Unit 2 refueling outage and storing FLEX equipment. EGC is proceeding with these activities to support implementation of Limerick Generating Station, Unit 2 mitigation strategies. Other FLEX equipment, modifications, and procedures required to implement the mitigating strategies required by Order EA-12-049, except for the primary containment venting strategy, will be completed and available for use in accordance with the implementation schedule requirements specified in the Order.

Justification for Relaxation Request:

EGC's work in developing, implementing, and maintaining guk:tance and strategies to maintain or restore core cooling, containment cooling, and spent fuel pool cooling was performed following the NRC-endorsed guidance in Nuclear Energy Institute (NEI) 12-06 (Reference 5), including the selection of type and location of the two FLEX Storage Robust Buildings presently under construction. Due to the site configuration and to improve the site's response strategy, two FLEX Storage Robust Buildings are required to be constructed. The first building is constructed of reinforced concrete approximately 40' wide x 7 5' bng x 21' high and located inside the Protected Area. The second building is constructed of reinforced concrete approximately 60' wide x 90' bng x 21' high and located outside the Protected Area. These bu i Id in gs have been designed for seismic, wind, tornado and tornado missiles, and flooding conditions. The buildings will store the equipment needed to support the FLEX mitigation strategies and the buildings will be equipped with h eat i n g and fans for internal environmental control. The equipment will be stored in a manner to prevent seismic interaction.

The design of the two FLEX Storage Robust Buik:Jings was scheduled to be completed in September 2014, with the construction to begin after the approval of the design and complete in April 2015. Due to the Limerick Station response strategy requiring two modified storage buildings, building design changes from the standard Exelon fleet design were required and caused significant delays in the completion of the building design. The construction of the buildings ,was delayed approximately 90 days due to design approvals and permitting, and actual construction was started in January 2015. This delay caused the building construction to be performed during the winter months where adverse weather conditions impeded the 2

ATIACHMENT REQUEST FOR SCHEDULE RELAXATION OF NRC ORDER EA-12-049 REQUIREMENT IV.A.2 FOR LIMERICK GENERATING STATION, UNIT 2 construction of the buildings. During the construction of the buildings there were an additional 35 days lost due to snow and/or high wind conditions (delayed concrete pours, snow removal, crane operation restrictions, and delayed rebar installation). The progress of work was also slower than initially estimated due to the extreme cold conditions.

The original construction schedule was for work to be performed 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> per day, 5 days per week. Once it was determined that the construction of the building was not meeting the construction schedule, recovery efforts were implemented. In order to recover the lost time due to the inclement weather, the work schedule was increased to 1O hours per day, 6 days per week. As additional delays were caused by inclement weather, a second shift was added, also working 1O hours per day, 6 days per week.

The completion of the two FLEX Storage Robust Buik:lings is the only item affecting the compliance schedule. Other FLEX equipment and modifications required to implement the mftigation strategies required by NRC Order EA-12-049, except for primary containment venting strategies, will be completed and available for use in accordance with the implementation schedule requirements specified in the Order.

Based on the negative impact on the construction progress of the two FLEX Storage Robust Buildings and the possibility of further delays caused by inclement weather, EGC is requesting that the Director, Office of Nuclear Reactor Regulation, relax the requirement for the schedule of compliance implementation for Unit 2, as prescribed in Section IV.A.2 of the Order. Presently, the Unit 2 FLEX Order compliance date is prior to restart from the Li2R13 refueling outage, except for the primary containment venting strategy. EGC requests a relaxation of the Limerick Generating Station, Unft 2 FLEX compliance date to no later than 90 days following restart from the Li2R13 refueling outage.

The requested relaxation of 90 days has been determined to be adequate to recover from the delays due to the completion and approval of the design and the delays caused by the inclement weather. This will allow the station to safely finish construction activities in support of implementation of the FLEX mitigation strategies for Limerick Generating Station, Unit 2. EGC is confident that the two FLEX Storage Robust Buildings will be completed and become operational within the 90-day extension.

The mftigation strategy requirements imposed by NRC Order EA-12-049 provide additional defense-in-depth measures for mitigating consequences of a beyond-design-basis external event. A sequence of events such as the Fukushima Dai-ichi accident is unlikely to occur in the United States based on current regulatory requirements and existing plant capabilities. Therefore, allowing additional time for completion of the FLEX Storage Robust Buildings is not a significant increase in plant risk. Other design changes, equipment procurement, and programmatic changes required to implement the Limerick Generating Station Unit 2 mitigation strategies will be completed and implemented in accordance with the current requirements of NRC Order EA-12-049, except for the primary containment venting strategy. The supporting FLEX mitigating strategy equipment will be onsite and available. During the extension period, until the equipment can be moved into the FLEX Storage Robust Buildings, the key equipment (large generators and pumps) will be stored in locations which provide physical separation, while maintaining post event 3

ATTACHMENT REQUEST FOR SCHEDULE RELAXATION OF NRC ORDER EA*12*049 REQUIREMENT IV.A.2 FOR LIMERICK GENERATING STATION, UNIT 2 deployment capability. This minimizes the likelihood of one event impacting both sets of equipment. The locations are not susceptible to flooding events or the impact of a building collapse. In the case of a predicted hurricane, one set of equipment will be moved to a protected location. These strategies provide enhanced plant capability to mitigate beyond-design-basis external events. Therefore, the requested relaxation does not reduce nuclear safety or safe plant operations.

==

Conclusion:==

As described above, compliance with the NRG Order EA-12-049 schedule required for completion of implementation of mitigation strategies and equipment would result in significant hardship and unusual difficulty without a compensating increase in the level of safety. An additional 90 days following startup from the Limerick Generating Station, Unit 2, Li2R13 (Spring 2015) refueling outage is required in order to allow completion of construction of the FLEX Storage Robust Buildings identified above. Therefore, in accordance with the provisions of Section IV of the Order, we request relaxation of the requirement described in Section IV.A.2.

References:

1. NRG Order 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. Exelon Generation Company, LLC letter to USNRC, "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 EA-12-049)," dated February 28, 2013 (RS-13-022}

3. NRG Letter to Exelon Generation Company, LLC, Limerick Generating Station Units 1 and 2-Relaxation of Certain Schedule Requirements for Order EA-12-049, "Issuance of Order to Modify Licenses with Regard to Requirements for Mitigation Strategies for Beyond Design Basis External Events," dated April 15, 2014

4. NRG Order EA-13-109, "Order Modifying Licenses With Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," dated June 6, 2013

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

Revision 0, dated August 2012 4