Summary of the Uncertainty Analyses for the State-of-the-Art Reactor Consequence Analyses Project (NUREG-2254)

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Publication Information

Manuscript Completed: March 2022
Date Published: October 2022

Prepared by:
S.T. Ghosh*, N.E. Bixler**, D. Brooks**, M.L. Dennis**,
H. Esmaili*, C. Faucett**, R.O. Gauntt**, S. Haq*, T. Haskin**,
A.G. Hathaway*, P.D. Mattie**, D. Osborn**, K.W. Ross**,
K.C. Wagner**

*U.S. Nuclear Regulatory Commission

**Sandia National Laboratories
   P.O. Box 5800
   Albuquerque, NM 87185

S.Tina Ghosh, NRC Project Manager

Office of Nuclear Regulatory Research
U.S. Nuclear Regulatory Commission
Washington, DC 20555-0001

Availability Notice


The U.S. Nuclear Regulatory Commission, with the assistance of Sandia National Laboratories, conducted three uncertainty analyses (UAs) from 2010 through 2019 as part of the State-of-the-Art Reactor Consequence Analyses (SOARCA) studies. The SOARCA project was initiated to leverage decades’ worth of research into severe accidents and apply modern analytical tools and techniques to develop a body of knowledge about the realistic consequences of severe nuclear reactor accidents. The original study focused on providing a "best estimate" evaluation for select scenarios. The SOARCA UAs extended this work to include an integrated evaluation and propagation of uncertainty through detailed accident progression, radiological release, and offsite health consequence modeling using the MELCOR and MACCS codes. As such, the first of the three UAs was a first-of-a-kind analysis. This report presents important results and insights as well as the methodology and scope of the three SOARCA UAs, including the UA results often of most interest in severe accident consequence and risk studies (i.e., cesium and iodine releases and offsite latent cancer fatality risk). This report also presents key insights into input variables and associated phenomena that most influenced variations in source term and offsite health consequences, as well as other observations on UA methodology.

Page Last Reviewed/Updated Monday, October 17, 2022