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Materials Science & Technology
The objectives of MSTD are: promote the advancement of materials science in Nuclear Science Technology; support the multidisciplines which constitute it; encourage research by providing a forum for the presentation, exchange, and documentation of relevant information; promote the interaction and communication among its members; and recognize and reward its members for significant contributions to the field of materials science in nuclear technology.
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2025 ANS Annual Conference
June 15–18, 2025
Chicago, IL|Chicago Marriott Downtown
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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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BREAKING NEWS: Trump issues executive orders to overhaul nuclear industry
The Trump administration issued four executive orders today aimed at boosting domestic nuclear deployment ahead of significant growth in projected energy demand in the coming decades.
During a live signing in the Oval Office, President Donald Trump called nuclear “a hot industry,” adding, “It’s a brilliant industry. [But] you’ve got to do it right. It’s become very safe and environmental.”
Kirk A. Mathews
Nuclear Science and Engineering | Volume 132 | Number 2 | June 1999 | Pages 155-180
Technical Paper | doi.org/10.13182/NSE99-A2057
Articles are hosted by Taylor and Francis Online.
Discrete ordinates calculations are presumed to translate particles from cell to cell in the directions specified in the angular set. This should result in uncollided particles from a small source propagating through the spatial mesh in narrow beams in these directions. Accurate high-order angular quadratures presume accurately attenuated propagation in the intended directions. This work examines the ability of various spatial quadratures to propagate rays correctly. Some widely used methods are shown to fail at this fundamental task. Diamond-difference approximations introduce undamped lateral oscillations, resulting in severely unphysical flux representations. Nonlinear fixups can prevent negativity but do not correct the underlying failure to properly propagate rays. First-moment conserving schemes tend to be successful but can be degraded in performance by simplifying approximations that are often used. Characteristic schemes are shown to have significant advantages. New characteristic methods are developed here that are exact (in a certain sense) in propagating rays and that uncouple the calculation of adjacent spatial cells in the mesh sweep. This enables DO loops to be converted to DO INDEPENDENT loops, with obvious implications for vector and/or parallel implementations.