ML14303A258

10 CFR Part 21 Notification of an Error in Powerplex MCPR and LHGR Limit Input for Browns Ferry, Unit 2

ML14303A258
Person / Time
Site:	Browns Ferry, PROJ0728
Issue date:	10/27/2014
From:	Salas P AREVA
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
NRC:14:058
Download: ML14303A258 (3)

Text

A AREVA October 27, 2014 NRC:14:058 U.S. Nuclear Regulatory Commission Document Control Desk 11555 Rockville Pike Rockville, MD 20852 10 CFR Part 21 Notification of an Error in POWERPLEX MCPR and LHGR Limit Input for Browns Ferry Unit 2 This letter provides notification of a reportable defect in accordance with 10 CFR Part 21. This situation was reported to the NRC Operations Center by facsimile on October 3, 2014.

As described in the attached defect report, the defect is an omission in the input to the POWERPLEX core monitoring software that could result in the application of non-conservative nuclear fuel operating thermal limits when the reactor is operated at 25% to 30% power. In the event of an abnormal operational occurrence (AOO) while operating in this power range, a fuel thermal safety limit could be exceeded. It should be noted that Browns Ferry Unit 2 Cycle 18 never experienced an AOO while supported by the non-conservative limits.

The affected utility has been informed and the planned actions and actions already taken to address the issue are provided in the attachment to this letter.

If you have any questions related to this information, please contact Alan Meginnis by telephone at (509) 375-8266, or by e- ail at Alan.Meginnis@areva.com.

Pedr Salas ctor Affa irs AREVA Inc.

cc: J. G. Rowley Project 728 AREVA INC.

3315 Old Forest Road, Lynchburg, VA 24501 Tel.: 434 832 3000 - www.areva.com

Document Control Desk NRC:14:058 October 27, 2014 Page 2 Reportable Defect (i) Name and address of the individualor individualsinforming the Commission.

Alan B. Meginnis, AREVA Inc., 2101 Horn Rapids Road, Richland, WA 99354.

(ii) Identification of the facility, the activity, or the basic component suppliedfor such facility or such activity within the United States which fails to comply or contains a defect.

The defect is in the input to a program that calculates the minimum critical power ratio (MCPR) and linear heat generation rate (LHGR) thermal limits for Browns Ferry Unit 2 Cycle 18.

(iii) Identification of the firm constructingthe facility or supplying the basic component which fails to comply or contains a defect.

AREVA Inc.

(iv) Nature of the defect orfailure to comply and the safety hazard which is created or could be createdby such defect orfailure to comply.

This issue is a defect as defined in 10 CFR 21.3.

The error is an omission in the POWERPLEX core monitoring software system input that could result in the application of non-conservative nuclear fuel operating thermal limits when the reactor is operated at 25 to 30% power. In the event of an abnormal operational occurrence while operating in this power range, a fuel thermal safety limit could be exceeded.

(v) The date on which the information of such defect orfailure to comply was obtained.

August 28, 2014 (vi) In the case of a basic component which contains a defect orfails to comply, the number and location of these components in use at, suppliedfor, being supplied for, or may be supplied for, manufactured, or being manufacturedfor one or more facilities or activitiessubject to the regulations in this part.

The defect exists only for Browns Ferry Unit 2 Cycle 18.

(vii) The corrective action which has been, is being, or will be taken; the name of the individual or organizationresponsiblefor the action; and the length of time that has been or will be taken to complete the action.

AREVA Inc. recommended plant operations be restricted to provide enough margin to the MCPR and LHGR thermal limits anytime power is in the range 25% < P < 30%. AREVA has also provided revised POWERPLEX input to TVA for Browns Ferry Unit 2 Cycle 18 to correct the error permanently.

Document Control Desk NRC:14:058 October 27, 2014 Page 3 (viii) Any advice relatedto the defect orfailure to comply about the facility, activity, or basic component that has been, is being, or will be given to purchasersor licensees.

This defect only had the potential to exceed the safety limit minimum critical power ratio (SLMCPR) and/or one of the Specified Acceptable Fuel Design Limits if an AOO occurred during the brief periods the plant was at power levels in the range 25% ! P < 30% during Cycle 18. The plant has not had any such events in Cycle 18.

The Identified defect is a human performance error impacting only Browns Ferry Unit 2 Cycle 18. It does not affect other operating cycles, Browns Ferry Units, or other nuclear plants.