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Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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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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Latest News
Canada clears Darlington to produce Lu-177 and Y-90
The Canadian Nuclear Safety Commission has amended Ontario Power Generation’s power reactor operating license for Darlington nuclear power plant to authorize the production of the medical radioisotopes lutetium-177 and yttrium-90.
D. R. Harris
Nuclear Science and Engineering | Volume 21 | Number 3 | March 1965 | Pages 369-381
Technical Paper | doi.org/10.13182/NSE65-A20040
Articles are hosted by Taylor and Francis Online.
Fluctuations of the neutron populations in various phase-space regions in a reactor have been examined by development of a three-step analysis. First, the usual transport equation, or an approximation to it, is used to compute the probability that a neutron injected at a certain location in the reactor gives rise to a chain-related descendant neutron in each of a number of differential volume elements in phase space. Second, these conditional probabilities are used to compute product densities, probabilities that nuclear reactions of a certain class are induced in various time intervals by neutrons in each of a number of differential volume elements. Finally, the product densities are used to compute local population moments, parameters arising in the Rossi alpha experiment, auto- and cross-correlation functions, and other quantities of interest in fluctuation studies. The analysis, as applied to various reactor geometries, shows that the usual point-reactor analysis of reactor neutron fluctuations can lead to substantial error in predicting fluctuation magnitudes in startup studies and in determination of some reactor parameters from fluctuation experiments.