ML15345A407

Monticello - License Amendment Request for Areva Extended Flow Window, Supplement to Provide Revised Analysis of Anticipated Transient Without Scram Instability

ML15345A407
Person / Time
Site:	Monticello
Issue date:	12/08/2015
From:	Gardner P A Northern States Power Co, Xcel Energy
To:	Document Control Desk, Office of Nuclear Reactor Regulation
Shared Package
ML15345A414	List: L-MT-15-081, ANP-3435NP, Revision 1, Areva Responses to RAI-8 and RAI-32 from Srxb and Snpb on MNGP EFW Lar. ML15345A407
References
L-MT-15-081, TAC MF5002
Download: ML15345A407 (3)

Text

ENCLOSURE 1 CONTAINS PROPRIETARY INFORMATIONWITHHOLD FROM PUBLIC DISCLOSURE IN ACCORDANCE WITH 10 CFR 2.390XcelEnergy@Monticello Nuclear Generating Plant2807 W County Rd 75Monticello, MN 55362December 8, 2015L-MT-1 5-08110 CFR 50.90U.S. Nuclear Regulatory CommissionATTN: Document Control DeskWashington, DC 20555-0001Monticello Nuclear Generating PlantDocket 50-263Renewed License No. DPR-22License Amendment Request for AREVA Extended Flow WindowSupplement to Provide Revised Analysis ofAnticipated Transient Without Scram Instability (TAC No. MF5002)References:1) Letter from Karen D. Fili (NSPM), to Document Control Desk (NRC),"License Amendment Request for AREVA Extended Flow Window,"L-MT-14-044, dated October 3, 2014. (ADAMS Accession No.ML1 4283A1 25)2) Email T. Beltz (NRC) to G. Adams (NSPM), "Monticello NuclearGenerating Plant -Requests for Additional Information (SRXBISNPB)re: AREVA Extended Flow Window License Amendment Request(TAC No. MF5002)," dated August 5, 2015.3) Letter from Peter A. Gardner (NSPM) to Document Control Desk(NRC), "License Amendment Request for AREVA Extended FlowWindow Supplement to Respond to NRC Staff Questions (TAC No.MF5002)," L-MT-1 5-065, dated September 29, 2015.In Reference 1, Northern States Power Company, a Minnesota corporation (NSPM),doing business as Xcel Energy, requested approval of an amendment to the MonticelloNuclear Generating Plant (MNGP) Renewed Operating License (OL) and TechnicalSpecifications (TS). The proposed change would revise MNGP TS and would approvecertain analytical methods that together would support operation in the expandedpower-flow operating domain described as the Extended Flow Window (EFW). Thepurpose of the requested amendment is to transition from the General Electricmethodology called Maximum Extended Load Line Limit Analysis Plus (MELLLA+) tothe AREVA methodology called EFW.

Document Control DeskPage 2In Reference 2, NRC Reactor Systems Branch and Nuclear Performance and CodeReview Branch (SRXB/SNPB) Staff requested additional information to support theirreview. Reference 3 provided information responsive to that request, including asummary of the revised analysis of the Anticipated Transient Without Scram -Instability(ATWS-I) event for MNGP. That information was enclosed in Reference 3 as AREVAReports ANP-3435P and ANP-3435NP (collectively referred to as ANP 3435P/NP),Revision 0. As discussed in Reference 3 and subsequently confirmed under theAREVA corrective action program, the results of ANP-3435P/NP Revision 0 wereaffected by an error in the ARE VA core depletion code (MICROBURN-B2) thatgenerated certain inputs for ANP-3435P/NP. That first error dealt with hydraulicsolution convergence at low-flow conditions. A second error was subsequentlydiscoyered and communicated to NRC Staff by electronic mail dated No~vember 11,2015. That second error dealt with void quality correlation values at low-flow conditions.The purpose of this letter is to provide Revision 1 to ANP-3435P/NP, which usescorrected inputs from MICROBURN-B2 to provide new results for the ATWS-l event.Correction of the convergence error and the void quality correlation (Dix-Findlay) errorresulted in the following net changes to results of the ATWS-I analysis:* 7 degree Fahrenheit (0F) decrease in the peak clad temperature (PCT) calculated forthe ATWS-I mitigated case (limiting case) presented in ANP-3435P/NP. Theresulting PCT of 1537°F still provides ample margin to the acceptance criterion of2200°F.* A relatively small reduction in margin for ATWS-l operator response. Thepreviously-submitted analysis provided a margin of more than 55 seconds beyondthe 90-second operator response time that precludes a temperature excursion. Therevised analysis would reduce that margin from 55 seconds to 48 seconds.These corrections to AREVA's MICROBURN-B2 core depletion code affect inputs to theanalysis in ANP-3435P/NP, but do not affect the analytical methodology beingreviewed. The effects of these errors and the results of the revised analyses werediscussed with NRC Staff in a teleconference on November 24, 2015. Also discussedwas the effect that the errors had on non-limiting transient cases. Based on the non-limiting nature of these transient results, and the fact that the analysis conclusions andsafety limits do not change, other non-consequential effects are being managed underthe AREVA and NSPM corrective action programs.Enclosure 1 provides AREVA Report ANP-3435P, Revision 1. Enclosure 1 isproprietary to AREVA. Enclosure 2 provides the non-proprietary AREVA Report ANP-3435NP, Revision 1.Enclosure 3 provides an affidavit executed to support withholding Enclosure 1 frompublic disclosure. Enclosure 1 contains proprietary information as defined by 10 CFR2.390. The affidavit sets forth the basis on which the information may be withheld frompublic disclosure by the NRC and addresses with specificity the considerations listed in10 CFR 2.390(b)(4). Accordingly, NSPM respectfully requests that the AREVA Document Control DeskPage 3proprietary information in Enclosure 1 be withheld from public disclosure in accordancewith 10 CFR 2.390(a)4, as authorized by 10 CFR 9.17(a)4. Correspondence withrespect to the copyright or proprietary aspects of the AREVA information in Enclosure 1or the supporting AREVA affidavit in Enclosure 3 should be addressed to Mr. AlanMeginnis, Manager- Product Licensing, AREVA Inc., 2101 Horn Rapids Road,Rich land, Washington 99354.The information offered herein does not affect the conclusions of the SignificantHazards Consideration and the Environmental Consideration evaluations provided inthe Reference 1 license amendment request.In accordance with 10 CFR 50.91(b), a copy of this application supplement is beingprovided to the designated Minnesota Official without enclosures.If there are any questions or if additional information is needed, please contact GlennAdams at 612-330-6777.Summary of CommitmentsThis letter makes no new commitments and no revisions to existing commitments.I declare under penalty of perjury that the foregoing is true and correct.Executed on: December 8, 2015Peter A. GardnerSite Vice PresidentMonticello Nuclear Generating PlantNorthern States Power Company-MinnesotaEnclosures (3)cc: Administrator, Region Ill, USNRCProject Manager, Monticello Nuclear Generating Plant, USNRCResident Inspector, Monticello Nuclear Generating Plant, USNRCMinnesota Department of Commerce (w/o enclosures)