05000269/LER-2011-005, Regarding Reactor Protective System Overpower Flux/Flow Imbalance Channels Inoperable

Regarding Reactor Protective System Overpower Flux/Flow Imbalance Channels Inoperable

ML11224A007
Person / Time
Site:	Oconee
Issue date:	08/09/2011
From:	Gillespie T Duke Energy Carolinas
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
LER 11-005-00
Download: ML11224A007 (3)

LER-2011-005, Regarding Reactor Protective System Overpower Flux/Flow Imbalance Channels Inoperable

Event date:
Report date:
Reporting criterion:	10 CFR 50.73(a)(2)(v), Loss of Safety Function
2692011005R00 - NRC Website

text

SDuke T. PRESTON GILLESPIE, JR.

Dukeg Vice President Energy.

Oconee Nuclear Station Duke Energy ON01 VP / 7800 Rochester Hwy.

Seneca, SC 29672 864-873-4478 864-873-4208 fax T. Gillespie@duke-energy. com August 9, 2011 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555

Subject:

Oconee Nuclear Station Docket No. 50-269 Licensee Event Report 50-269/2011-05, Revision 0 Problem Investigation Program No.: 0-11-7081 Gentlemen:

Pursuant to 10 CFR 50.73 Sections (a)(1) and (d), attached is Licensee Event Report 269/2011-05, Revision 0, regarding the incorrect wiring of all four channels of power range nuclear instrumentation. This report is being submitted in accordance with 10 CFR 50.73 (a)(2)(v)(D). This event is considered to have no consequence with respect to the health and safety of the public.

Other than the commitment to submit a LER supplement, there are no regulatory commitments contained in this report. Duke Energy Carolinas, LLC, expects to provide the supplement within 60 days, but does not consider that time frame to be a

commitment

Any questions regarding the content of this report should be directed to Sandra N. Severance, Oconee Regulatory Compliance, at 864-873-3466.

Sincerely, T. Preston Gillespie, Jr.

Vice President Oconee Nuclear Site Attachment www. duke-energy. com

Document Control Desk August 9, 2011 Page 2 cc:

Mr. Victor McCree Administrator, Region II U.S. Nuclear Regulatory Commission Marquis One Tower 245 Peachtree Center Ave., NE, Suite 1200 Atlanta, GA 30303-1257 Mr. John Stang Project Manager U.S. Nuclear Regulatory Commission Office of Nuclear Reactor Regulation Washington, D.C. 20555 Mr. Andrew Sabisch NRC Senior Resident Inspector Oconee Nuclear Station INPO (Word File via E-mail)

Abstract

During startup from Refueling Outage 1 EOC26 for Unit 1 on 6/10/2011, during which implementation of the digital Reactor Protection System/Engineered Safeguards (RPS/ES) upgrade was performed, and after increasing power to 48 percent, Reactor Engineering questioned the RPS power range nuclear instrumentation (NI) that, although appearing to respond appropriately for total reactor power, did not appear to be responding adequately to power imbalance differences.

Investigation into the cause of the Unit 1 NI imbalance indications revealed that the triaxial cables for the top and bottom detector NI signals were reversed at the RPS Power Range Test Module for each RPS channel. At 0802 on 6/10/2011, the four channels were declared inoperable. This resulted in a loss of safety function per 10 CFR 50.73(a)(2)(v)(D) and Technical Specification 3.3.1, Conditions B and C were entered.

This event was reported via an 8-hour notification per 10 CFR 50.72(b)(3)(v)(D) on 6/10/2011 (Event Report 46947). The triaxial cable connections were corrected and the RPS channels were declared operable at 1511 on 6/10/2011. Evaluation of this event is ongoing regarding the inoperability of these channels. The results of this evaluation will be reported in the supplement to this report. This event is considered to have no consequence with respect to the health and safety of the public.

NRC FORM 366 (10-2010)