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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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The Standards Committee is responsible for the development and maintenance of voluntary consensus standards that address the design, analysis, and operation of components, systems, and facilities related to the application of nuclear science and technology. Find out What’s New, check out the Standards Store, or Get Involved today!
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Hash Hashemian: Visionary leadership
As Dr. Hashem M. “Hash” Hashemian prepares to step into his term as President of the American Nuclear Society, he is clear that he wants to make the most of this unique moment.
A groundswell in public approval of nuclear is finding a home in growing governmental support that is backed by a tailwind of technological innovation. “Now is a good time to be in nuclear,” Hashemian said, as he explained the criticality of this moment and what he hoped to accomplish as president.
G. L. Mesina, D. L. Aumiller, F. X. Buschman
Nuclear Science and Engineering | Volume 182 | Number 1 | January 2016 | Pages 1-12
Technical Paper | Special Issue on the RELAP5-3D Computer Code | doi.org/10.13182/NSE14-151
Articles are hosted by Taylor and Francis Online.
Large computer programs like RELAP5-3D solve complex systems of governing, closure, and special process equations to model the underlying physics of thermal-hydraulic systems and include specialized physics for the modeling of nuclear power plants. Further, these programs incorporate other mechanisms for selecting optional code physics, input, output, data management, user interaction, and post-processing. Before being released to users, software quality assurance requires verification and validation. RELAP5-3D verification and validation are focused toward nuclear power plant applications. Verification ensures that the program is built right by checking that it meets its design specifications, comparing coding algorithms to equations, comparing calculations against analytical solutions, and the method of manufactured solutions.
Sequential verification performs these comparisons initially, but thereafter only compares code calculations between consecutive code versions to demonstrate that no unintended changes have been introduced. An automated, highly accurate sequential verification method, based on previous work by Aumiller, has been developed for RELAP5-3D. It provides the ability to test that no unintended consequences result from code development. Moreover, it provides the means to test the following code capabilities: repeated time-step advancement, runs continued from a restart file, and performance of coupled analyses using the R5EXEC executive program. Analyses of the adequacy of the checks used in these comparisons are provided.