ML14065A528

Relaxation of Certain Scheduler 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

ML14065A528
Person / Time
Site:	Limerick
Issue date:	04/15/2014
From:	Leeds E Office of Nuclear Reactor Regulation
To:	Pacilio M Exelon Generation Co
Bamford P, NRR/DORL, 415-2833
References
EA-12-049
Download: ML14065A528 (3)

Text

UNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D.C. 20555-0001 April15, 2014 Mr. Michael J. Pacilio President and Chief Nuclear Officer Exelon Generation Company, LLC 4300 Winfield Road Warrenville, IL 60555

SUBJECT:

LIMERICK GENERATING STATION, UNITS 1 AND 2- RELAXATION OF CERTAIN SCHEDULAR 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"

Dear Mr. Pacilio:

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), Units 1 and 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, reactor coolant system inventory, containment cooling, and spent fuel pool cooling capabilities during beyond design basis external events (BDBEEs). By letter dated March 12, 2012 (ADAMS Accession No. ML12054A694), the NRC ordered Exelon to install a reliable hardened containment vent system at LGS, Units 1 and 2, via Order EA-12-050. By letter dated June 6, 2013 (ADAMS Accession No. ML13143A321), the NRC superseded the requirements of Order EA-12-050, with Order EA-13-1 09, which requires the installation of reliable hardened containment vents capable of operation under severe accident conditions. The compliance date requirements of Order EA-13-1 09, Phase I (wetwell vent), extend beyond those of Order EA-12-049 for LGS, Units 1 and 2.

Section IV of Order EA-12-049 states that licensees proposing to deviate from requirements of the order may request that the Director, Office of Nuclear Reactor Regulation, relax or rescind certain requirements. By letter dated February 26, 2014 (ADAMS Accession No. ML14057A551 ), the licensee requested relief from the final compliance dates of Order EA 049. Specifically, the licensee requested an extension of one refueling cycle for LGS, Units 1 and 2, to complete full implementation of the hardened severe accident capable containment wetwell vent. The extension request was proposed because the installation of a containment wetwell vent that meets the requirements of Order EA-13-109, Phase I, will take additional time to complete, as compared to the compliance dates associated with Order EA-12-049.

To allow the time to design and install the severe accident capable hardened containment wetwell vent, and integrate it into the mitigating strategies required for Order EA-12-049, the licensee requests to relax the Order EA-12-049 full implementation date from the completion of the spring 2016 refueling outage for LGS Unit 1, to the completion of the spring 2018 refueling

M. Pacilio outage. For LGS Unit 2, the licensee requests a relaxation from the completion of the spring 2015 refueling outage to the completion of the spring 2017 refueling outage.

In light of the facts presented in the licensee's letter dated February 26, 2014, the NRC staff has determined that the licensee has presented good cause for a relaxation of the order implementation dates. The licensee proposes the equipment and modifications required to implement the mitigating strategies required by Order EA-12-049 will be completed and available for use in accordance with the original implementation schedule requirements, except for the primary containment venting strategy. Until the full containment wetwell venting capability required by Order EA-13-1 09 is implemented, LGS will maintain a containment venting strategy in accordance with existing emergency operating procedures at each unit. By completing the specified plant configuration changes (other than the severe accident capable containment wetwell vent), and maintaining the ability to vent containment in accordance with existing procedures, a portion of the desired increase in capability to respond to a BDBEE will be realized within the timeframe specified in Order EA-12-049. The requested extension allows the licensee sufficient time to install the enhanced containment wetwell vent capability necessary for full Order EA-12-049 compliance within an appropriate amount of time, consistent with the requirements of Order EA-13-1 09. The NRC staff also considered that, following the accident at Fukushima Dai-ichi, the NRC 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. The NRC staff therefore approves the relaxation of the order implementation dates.

Accordingly, based upon the authority granted to the Director, Office of Nuclear Reactor Regulation, the requirement of the order for full implementation is relaxed until the completion of the spring 2018 refueling outage for LGS, Unit 1, and the completion of the spring 2017 refueling outage for LGS, Unit 2, to allow the licensee sufficient time to implement a severe accident capable hardened containment wetwell vent at each respective unit.

If you have any questions, please contact Peter Bamford at 301-415-2833.

Eric J. eeds, Director Office of Nuclear Reactor Regulation Docket Nos. 50-352 and 50-353 cc: Listserv

ML14065A528 OFFICE NRR/MSD/MSPB/PM NRR/MSD/MSPB/LA NRR/MSD/MRSB/BC NRR/MSD/MSPB/BC NAME PBamford Slent SWhaley JBowen DATE 03/06/14 03/07/14 03/10/14 03/14/14 OFFICE OE OGC MSD/0 NRR/0 NAME RFretz CHair JDavis Eleeds DATE 03/18/14 03/25/14 03/30/14 04/15/14