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Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
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2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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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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Latest News
Proving DRACO will deliver
The United States is now closer than it has been in over five decades to launching the first nuclear thermal rocket into space, thanks to DRACO—the Demonstration Rocket for Agile Cislunar Orbit.
Emily R. Wolters, Edward W. Larsen, William R. Martin
Nuclear Science and Engineering | Volume 174 | Number 3 | July 2013 | Pages 286-299
Technical Paper | doi.org/10.13182/NSE12-72
Articles are hosted by Taylor and Francis Online.
In this paper, two modifications to improve the efficiency of Lee et al.'s recently proposed “CMFD [coarse-mesh finite difference]-accelerated Monte Carlo” method for neutron criticality problems are presented and tested. This CMFD method employs standard Monte Carlo techniques to estimate nonlinear functionals (ratios of integrals), which are used in low-order CMFD equations to obtain the eigenvalue and discrete representations of the eigenfunction. In a “feedback” procedure, the Monte Carlo fission source is then modified to match the resulting CMFD fission source. The proposed new methods differ from the CMFD-accelerated Monte Carlo method only in the definition of the nonlinear functionals. The new methods are compared with the CMFD-accelerated Monte Carlo method for two high-dominance-ratio test problems. All of the hybrid methods rapidly converge the Monte Carlo fission source, enabling a large reduction in the number of inactive cycles. However, the new methods stabilize the fission source more efficiently than the CMFD-accelerated Monte Carlo method, enabling a reduction in the number of active cycles as well. Also, in all the hybrid methods, the apparent variance of the eigenfunction is nearly equal to the real variance, so the real statistical error is well estimated from a single calculation. This is a major advantage over the standard Monte Carlo method, in which the real variance is typically underestimated due to intercycle correlations.