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Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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2025 ANS Annual Conference
June 15–18, 2025
Chicago, IL|Chicago Marriott Downtown
Standards Program
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.”
Patrick S. Brantley, Edward W. Larsen
Nuclear Science and Engineering | Volume 134 | Number 1 | January 2000 | Pages 1-21
Technical Paper | doi.org/10.13182/NSE134-01
Articles are hosted by Taylor and Francis Online.
The simplified P3 (SP3) approximation to the multigroup neutron transport equation in arbitrary geometries is derived using a variational analysis. This derivation yields the SP3 equations along with material interface and Marshak-like boundary conditions. The multigroup SP3 approximation is reformulated as a system of within-group problems that can be solved iteratively. An "explicit" iterative algorithm for solving the within-group problem is described, Fourier analyzed, and shown to be more efficient than the traditional FLIP implicit algorithm. Numerical results compare diffusion (P1), simplified P2 (SP2), and simplified P3 calculations of a mixed-oxide (MOX) fuel benchmark problem to a reference transport calculation. The SP3 approximation can eliminate much of the inaccuracy in the diffusion and SP2 calculations of MOX fuel problems.
