ML14034A049

Response to Request for Additional Information Regarding Response to Bulletin 2012-01, Design Vulnerability in Electric Power System.

ML14034A049
Person / Time
Site:	Davis Besse
Issue date:	02/03/2014
From:	Lieb R A FirstEnergy Nuclear Operating Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
BL-12-001, L-14-03, TAC ME9326
Download: ML14034A049 (3)

Text

FENOC-\FirstEneryy Nuclear Opanting Cam pany 5501 North Staic noub 2 Oak Harbor, Ahio 43449 Raymond A. Ueb Vice Prasident, Nuclear February 3,2014 L-14-039 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DG 20555-0001 419-321-7676 Fas<: 41*321-7582 10 cFR 50.54(0

SUBJECT:

Davis-Besse Nuclear Power Station Docket No. 50-346, License No. NPF-3 Response to. Req uest for Ad d itional I nfo rmation Rega rd ing.. Resppnse to Bulletin 2Q1?-01. "Des_ign Vulnerabilily irtElectric Power:,$ystgr,n" (TAC.No. ME9326)FirstEnergy Nuclear Operating Company responded to Nuclear Regulatory Commission (NRC)Bulletin 2012-01, "Design Vulnerability in Electric Power System," in a letter dated October 24,2A12 (Agencyruide Documents Access and Management System (ADAMS) Accession No. MI12299A468).

The NRC staff requested additional information in a letter dated December 20, 2013 (ADAMS Accession No.ML13351A314).

The requested information is provided for the Davis-Besse Nuclear Power Station in an attachment to this letter.There are no regulatory commitments contained in this submittal.

lf there are any questions or if additional information is required, please contact Mr. Thomas A, Lentz, Manager - Fleet Licensing, at 330-315-6810.

I declare under penalty of perjury that the foregoing is true and correct. Executed on February 3 , 2014.Sincerely,

Attachment:

Response to Request for Additional Information on Bulletin 2012-01 for the Davis-Besse Nuclear Power Station cc: NRC Region lll Administrator NRC Resident Inspector NRC Project Manager Utility Radiological Safety Board Raymond A. Lieb Attachment L-14-039 Response to Request for Additional Information on Bulletin 2012-01 for the Davis-Besse Nuclear Power Station Page 1 of 2 For the Davis-Besse Nuclear Power Station, FirstEnergy Nuclear Operating Company (FENOC) responded to Nuclear Regulatory Commission (NRC)Bulletin 2012-01,"Design Vulnerability in Electric Power System," in a letter dated October 24,2A12 (Agencywide Documents Access and Management System (ADAMS) Accession No.ML12299A468).

The NRC staff requested additional information in a letter dated December 20, 2013 (ADAMS Accession No. ML13351A314).

The requested information is identified using bold text, followed by the FENOC response.1. Provide a summary of all interim corrective actions that have been taken since the January 30, 2012, event at Byron Station, Unit 2,to ensure that plant operators can promptly diagnose and respond to open phase conditions on the offsite power circuits for ClasE-i E vital buses until permanent corrective actions are completed, Response: Lessons learned from the events at the Byron station were reviewed and various interim corrective actions evaluated for safety and efficiency at the Davis-Besse Nuclear Power Station (DBNPS). Based on the plant's offsite power configuration, electrical design details, and the lessons learned, the following actions were taken to ensure plant operators can diagnose and respond to an open phase condition:

Operator walkdowns (three times per week at a minimum) of the switchyard are performed to identify open phase condition vulnerabilities.

Bus transfer procedures were revised to ensure three phase voltages are checked prior to planned transfers to an offsite power circuit.Periodic surveillances (seven day Technical Specification Frequency) include steps to identify an open phase condition in the offsite power supply circuits.2. Provide a status and schedule for completion of plant design changes and modifications to resolve issues with an open phase of electric power.: Response: IndustrylDBNPS Status: Holders of operating licenses and combined licenses for nuclear power reactors are investigating options being researched by several vendors to detect open phase conditions, There is cui"rently no generic, off-the-shelf technology that has been proven to detect all the required open phase fault conditions for all plant and transformer designs.Holders of operating licenses and combined licenses for nuclear power reactors are engaged in devElopment of a Nuclear Energy Institute (NEl) Open Phase Condition Industry Guidance Document, as well as development of Attachment L-14-039 Page 2 of 2 enhancements to software tools being used to analyze open phase conditions.

A December 2013 version of the Open Phase Gondition Industry Guidance Document (NEl 13-12) was provided to the NRC in December.. With the goal of ensuring accurate detection without compromising nuclear safetyor increasing plant risk, new open phase condition technology will be thoroughly evaluated, tested, and analyzed before installation.. Vulnerability studies of open phase fault conditions have been started for the Davis-Besse Nuclear Power Station.DBNPS Schedule:. FENOC intends to meet the remaining milestones identified in the industry Open Phase Condition Initiative (October 2013; ADAMS Accession No, ML13333A1 47)for the Davis-Besse Nuclear Power Station; however, deviations may be required to accommodate outage schedules, software and hardware availability, manufacturer's delivery capabilities, or other unexpected delays.. Any deviation from the industry Open Phase Condition Initiative schedule will be documented through an appropriate deviation process. Revision 2 of the Open Phase Condition lndustry Guidance Document, which is scheduled to be issued in June 2014, is expected to provide a deviation process forthe industry.