ML072830334

Notification of Potential Part 21 Report - Areva Minimum Critical Power Ratio

ML072830334
Person / Time
Site:	Browns Ferry, Grand Gulf, Susquehanna, Columbia, River Bend, LaSalle
Issue date:	10/08/2007
From:	Holm J AREVA NP
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
43701
Download: ML072830334 (4)

Text

10/08/2007 U.S. Nuclear Regulatory Commission OperationsCenter Event Report Page I General Information or Other (PAR) Event# 43701 Rep Org: AREVA NP INC. Notification Date I Time: 10/08/2007 15:30 (EDT)

Supplier: AREVA NP INC. Event Date / Time: 08/13/2007 (PDT)

Last Modification: 10/08/2007 Region: 4 Docket #:

City: RICHLAND Agreement State: Yes County: License #:

State: WA NRC Notified by: JERALD HOLM Notifications: WILLIAM JONES R4 HQ Ops Officer: MARK ABRAMOVITZ MARVIN SYKES R1 Emergency Class: NON EMERGENCY CAROLYN EVANS R2 10 CFR Section: LAURA KOZAK R3 21.21 UNSPECIFIED PARAGRAPH VERN HODGE NRR JOHN THORP NRR PART 21 REPORT - AREVA MINIMUM CRITICAL POWER RATIO The licensee provided the following information via facsimile:

"The defect is inthe calculation of steady-state core Minimum Critical Power Ratio (MCPR) by the core monitoring system when the SPCB critical power correlation is used for ATRIUM-1 0 fuel. Specifically, the defect is in the additive constants, a parameter used by the SPCB critical power calculation and based on test data." AREVA notified the affected plants.

Affected Plants:

Browns Ferry, Units 2 & 3 Columbia Grand Gulf LaSalle, Units 1 & 2 River Bend Susquehanna, Units 1 & 2

/ ~7e~

II Received at: 10/08/2007 15:22 Oct 08 07 1 2 :25p AREVR FRRMRTME ANP 5093758965 p.I A AREVA NP Inc.

AREVA FAX To: NRC Operations Center Date: 10/8/2007 Time in: 12:24 PM Pages to follow: 2 Company: NRC From: J. S. Holm Telephone: 509-375-8142 MB: 36 M Original to be mailed LI Via fax only Receiving fax: 301-816-5151 Sending fax: 509-375-8965 Telephone: Fax verification: 509-375-8308 Extra Distribution to:

Message:

Reportable Defect This facsimile transmission is intended only the individual(s) named above. Itmay contain information which is legally privileged, confidential, or otherwise protected from disclosure by law. Any use of this transmission by Individuals olher than those named above is strictly prohibited. If you receive this transmission in error, please call the fax verification number above immediately, and mail the original transmission to us at the address set forth below. Thank you.

AREVA NP Inc. An AREVA and Siemens Company 2101 Horn Rapids Road Operator: S. K. McCoy Richland, WA 99354-5102 Telephone: (509) 375-8100 Log No.: Time Sent:

2 Oct 08 07 12:25p RREVn FRAMIRTME RNP 5093758965 p.

Reportable Defect (i) Name and address of the individual informing the Commission Jerald S. Holm, 2101 Horn Rapids Road, Richland, WA 99352 (ii) Identification of the facility, the activity, or the basic component supplied for such facility or such activity within the United States which fails to comply or contains a defect.

The defect is in the calculation of steady-state core Minimum Critical Power Ratio (MCPR) by the core monitoring system when the SPCB critical power correlation is used for ATRIUM-10 fuel. Specifically, the defect is in the additive constants, a parameter used by the SPCB critical power calculation and based on test data.

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

AREVA NP (iv) Nature of the defect or failure to comply and the safety hazard which is createdor could be created by such a defect or failure to comply.

The MCPR calculated by the core monitoring system is used to confirm that the core is operated within the required Operating Limit MCPR (OLMCPR).

The OLMCPR is established to ensure that the Technical Specification safety limit MCPR (SLMCPR) is not violated during anticipated operational occurrences (AOOs). The defect in the SPCB additive constants results in a non-conservative (high) prediction of MCPR. Therefore, the reactor could have been operated in violation of the OLMCPR and the SLMCPR could have been violated if the limiting AOO occurred at that time.

While the MCPR error is relatively small (<0.8%), if the reactors were operated on the operating limit, and the limiting transient were to occur, the technical specification MCPR safety limit would be violated. Therefore, the issue is considered a defect.

(v) The date on which the information of such a defect or failure to comply was ob taine d . 7  ? o, I This issue was determined to be a deviation on August 13, 2006/ o- ..

(vi) In the case of a basic component which fails to comply, the number and the location of all such components in use at, supplied for, or being supplied for one or more facilities or activities subject to the regulations in this part.

The defect exists in the calculation of steady-state core Minimum Critical Power Ratio (MCPR) by the core monitoring system for the following reactors:

Oct 08 07 12:25p AREvn FRnMATME ANP 5093758965 p.3 Browns Ferry Unit 2 and Unit 3 Columbia Grand Gulf LaSalle Unit 1 and Unit 2 River Bend Susquehanna Unit 1 and Unit 2 (vii) The corrective action which has been, is being, or will be taken; the name of the individual or organization responsible for this action; and the length of time that has been or will be taken to complete the action.

AREVA provided recommended compensatory actions to all affected plants.

The compensatory actions involve restricting allowed MCPR to compensate for the non-conservative prediction of steady-state MCPR by the core monitoring system.

The compensatory actions will be required until revised additive constants are developed and the input decks to the core monitoring system are updated.

(viii) Any advice related to the defect or failure to comply about the facility, activity, or basic component that has been, is being, or will be given to purchasersor licensees.

See (vii) above.