ML19052A413

NEI Submittal of Reactivity Decrement Bias and Uncertainty Values Using Linear Versus Quadratic Weighted Least Squares Regression Models, Comments on Revised Draft Safety Evaluation Report for Electric Power Research

ML19052A413
Person / Time
Site:	Nuclear Energy Institute
Issue date:	01/31/2019
From:	Ashkeboussi N Nuclear Energy Institute
To:	Mirela Gavrilas Office of Nuclear Reactor Regulation
Drake J, NRR/DLP, 415-8378
References
Download: ML19052A413 (2)

Text

From: ASHKEBOUSSI, Nima To: Gavrilas, Mirela Cc: Lund, Louise; Morey, Dennis; Lukes, Robert; Drake, Jason

Subject:

[External_Sender] Submittal of Reactivity Decrement Bias and Uncertainty Values Using Linear versus Quadratic Weighted Least Squares Regression Models, Comments on Revised Draft Safety Evaluation Report for Electric Power Research Institute Reports Date: Thursday, January 31, 2019 4:46:02 PM Attachments: 01-31-2019_NRC_EPRI Updates on SFP SER.PDF 01-31-2019_NRC_EPRI Updates on SFP SER_Attachment1_EPRI_Bias-Uncertainty....docx 01-31-2019_NRC_EPRI Updates on SFP SER_Attachment2_Comments_Draft-SER_Re....docx 01-31-2019_NRC_EPRI Updates on SFP SER_Attachment3_ProposedUtilizationRe....docx January 31, 2019 Dr. Mirela Gavrilas Director, Division of Reactor Safety Systems Office of Nuclear Reactor Regulation U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

Subject:

Submittal of Reactivity Decrement Bias and Uncertainty Values Using Linear versus Quadratic Weighted Least Squares Regression Models, Comments on Revised Draft Safety Evaluation Report for Electric Power Research Institute Reports Benchmarks for Qualifying Fuel Reactivity Depletion Uncertainty - Revision 1 and Utilization of the EPRI Depletion Benchmarks for Burnup Credit Validation - Revision 1, and Proposed Changes for the EPRI Utilization Report

Project Number: 689

Dear Dr. Gavrilas:

On behalf of the Nuclear Energy Institutes (NEI) members (hereinafter referred to as industry),

please see the attached comments to the revision of the updated U.S. Nuclear Regulatory Commission (NRC) draft Safety Evaluation (SE) for the Electric Power Research Institute (EPRI) reports Benchmarks for Qualifying Fuel Reactivity Depletion Uncertainty - Revision 1, and Utilization of the EPRI Depletion Benchmarks for Burnup Credit Validation - Revision 1. NEI previously submitted comments on the initial NRC draft SE on June 26, 2018. Additionally, in , we are submitting the uncertainty and bias values using linear versus quadratic weighted least squares regression models. We would specifically like to reiterate that the uncertainty values outlined in Attachment 1 did not change between the linear and quadratic regression approaches, but there was a change in the bias values, which is added as an additional NRC safety margin to the final analysis, per our discussion during the December 20, 2018 public meeting. In Attachment 3, we are submitting the proposed changes to the EPRI Utilization report to reflect this position. The attachments to this letter contain industrys detailed comments and analysis.

We appreciated the opportunity afforded to industry during the December 20, 2018, public meeting to discuss the draft SER, understand NRC concerns, resolve misunderstandings, and identify a path forward for closing this issue. As you know, NEI and industry have been working with the NRC for over seven years to establish regulatory guidance that may be used by the

industry to perform criticality analyses for the storage of spent fuel at light water power plants.

Based on the public meeting, we believe that the attachments and industrys comment on the draft SER have sufficiently incorporated the NRC staffs feedback. Given the long history of this issue, we believe it would be beneficial to review a final draft prior to publication to ensure that all changes reflect our mutual understanding and goal to have an SER that is both clear and usable.

Finalization of the NRC SER in a timely manner is important to appropriately revise the EPRI reports that contain the important scientific and technical underpinnings that inform NEI 12-16, Guidance for Performing Criticality Analyses of Fuel Storage at Light Water Reactor Plants, Revision 3. These EPRI reports are incorporated into NEI 12-16 by reference. The targeted NRC completion date of the third quarter of fiscal year 2019 would be helpful in achieving industrys objectives.

Thank you for your continued attention on this important matter. Please contact me if you have any questions or require additional information.

Sincerely, Nima Ashkeboussi Director, Fuel Cycle Programs Fuel & Radiation Safety Nuclear Energy Institute 1201 F St NW, Suite 1100 Washington, DC 20004 www.nei.org P: 202.739.8022 M: 202.375.0490 E: nxa@nei.org This electronic message transmission contains information from the Nuclear Energy Institute, Inc. The information is intended solely for the use of the addressee and its use by any other person is not authorized. If you are not the intended recipient, you have received this communication in error, and any review, use, disclosure, copying or distribution of the contents of this communication is strictly prohibited. If you have received this electronic transmission in error, please notify the sender immediately by telephone or by electronic mail and permanently delete the original message. IRS Circular 230 disclosure: To ensure compliance with requirements imposed by the IRS and other taxing authorities, we inform you that any tax advice contained in this communication (including any attachments) is not intended or written to be used, and cannot be used, for the purpose of (i) avoiding penalties that may be imposed on any taxpayer or (ii) promoting, marketing or recommending to another party any transaction or matter addressed herein.

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