ML15106A013

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.

ML15106A013
Person / Time
Site:	Limerick
Issue date:	04/29/2015
From:	Bill Dean Office of Nuclear Reactor Regulation
To:	Bryan Hanson Exelon Generation Co
Hughey J, NRR/JLD, 415-3204
References
EA-12-049, TAC MF6062
Download: ML15106A013 (4)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 April 29, 2015 Mr. Bryan C. Hanson President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LIMERICK GENERATING STATION, UNIT 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" (TAC NO. MF6062)

Dear Mr. Hanson:

By letter dated March 12, 2012 (Agencywide Documents Access and Management System (ADAMS) Accession No. ML12054A735), the U.S. Nuclear Regulatory Commission (NRC) ordered Exelon Generation Company, LLC (Exelon, the licensee) to take certain actions at Limerick Generating Station (LGS), Unit 2, associated with the Fukushima Near-Term Task Force Recommendations. Order EA-12-049 directed that actions be taken by licensees to develop and implement strategies to maintain or restore core cooling, containment cooling, and spent fuel pool cooling capabilities during beyond-design-basis external events.

Section IV of NRC Order EA-12-049 states that licensees proposing to deviate from requirements contained in the order may request that the Director, Office of Nuclear Reactor Regulation, relax or rescind certain requirements. Condition IV.A.2 of NRC Order EA-12-049 requires full implementation of the order requirements no later than two refueling cycles after submittal of the overall integrated plan, or by December 31, 2016, whichever comes first. By letter dated April 15, 2014 (ADAMS Accession No. ML14065A528), 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 LGS, Unit 2, consistent with the requirements of NRC Order EA-13-109, "Issuance of Order to Modify Licenses with Regard to Reliable Hardened Containment Vents Capable of Operation Under Severe Accident Conditions," dated June 6, 2013 (ADAMS Accession No. ML13143A334). The NRC relaxation approval dated April 15, 2014 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.

By letter dated April 2, 2015 (ADAMS Accession No. ML15092A833), the licensee informed the NRC of its additional LGS, Unit 2, request for schedule relaxation from compliance with Order EA-12-049 for no more than 90 days following restart from the spring 2015 refueling outage.

The additional schedule relaxation was requested to allow completion of two FLEX storage robust buildings, located in the LGS site protected areas.

B. Hanson The request dated April 2, 2015, stated that building design and permitting delays associated with the FLEX storage robust buildings resulted in a delay to the construction start date.

Additional delays were encountered due to building construction activities continuing into the winter months, where adverse weather conditions further impeded the work progress. The licensee also attributed delays to complications encountered in adapting the Exelon fleet single-building design to the LGS site specific application that required two separate buildings.

The licensee stated that the LGS portable FLEX equipment that will be stored in the completed FLEX storage robust buildings has been procured and is currently located onsite. In addition, the design and programmatic changes required to implement the LGS, Unit 2, mitigating strategies will be completed in accordance with the current requirements of Order EA-12-049, except for the primary containment venting strategy, as discussed above. Therefore, the FLEX mitigating strategy equipment will be onsite and available.

The licensee also stated that in order to maintain post-deployment capability, key FLEX equipment, such as large portable generators and pumps, will be stored in locations that provide physical separation during the requested 90-day extension period. The locations will not be susceptible to flooding events or building collapse, minimizing the likelihood of one event impacting both sets of equipment. If hurricane conditions are predicted, one set of portable FLEX equipment will be moved to a protected location.

In light of the facts presented in the licensee's April 2, 2015, letter, the NRG staff has determined that the licensee has demonstrated good cause to relax the NRG Order EA-12-049 implementation date for 90 days following restart from the spring 2015 refueling outage. The NRG staff also considered that, following the accident at Fukushima Dai-ichi, the NRG concluded that a sequence of events such as the Fukushima Dai-ichi accident is unlikely to occur in the United States based on the current regulatory requirements and existing plant capabilities. Given the plant-specific circumstances at Limerick, and that implementation of the mitigating strategies relaxed by this letter will be completed before December 2016, the NRG staff approves the requested relaxation.

Accordingly, based upon the authority granted to the Director, Office of Nuclear Reactor Regulation, the requirement of implementation of mitigating strategies for LGS, Unit 2, associated with Order EA-12-049 is relaxed until no later than 90 days following restart from the spring 2015 refueling outage. Full compliance with Order EA-12-049 remains relaxed to the completion of the spring 2017 refueling outage for LGS, Unit 2, as granted in NRG letter dated April 15, 2014, to allow the licensee sufficient time to implement a severe accident capable hardened containment wetwell vent.

B. Hanson If you have any questions, please contact John Hughey at 301-415-3204.

Sincerely,

&.11an, Direc,,....t...._o_r- - - - -

Office of Nuclear Reactor Regulation Docket No. 50-353 cc: Listserv

ML15106A013

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