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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 Winter Conference and Expo
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Orlando, FL|Renaissance Orlando at SeaWorld
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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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New laws offer nuclear industry incentives for existing power plant uprates
This year, the U.S. nuclear industry received a much-needed economic boost that could help preserve operating nuclear power plants and incentivize upgrades that extend their lifespan and power output.
Signed into law in 2022, the Inflation Reduction Act offers production tax credits (PTCs) for existing nuclear power plants and either PTCs or investment tax credits (ITCs) for new carbon-free generation. These credits could make power uprates—increasing the maximum power level at which a commercial plant may operate—a much more appealing option for utilities.
Keiichi Saito, Yukichi Taji
Nuclear Science and Engineering | Volume 30 | Number 1 | October 1967 | Pages 54-64
Technical Paper | doi.org/10.13182/NSE67-A17242
Articles are hosted by Taylor and Francis Online.
Statistical aspects of neutron transport in low-power reactors are studied from the viewpoint of branching processes. The probability generating function of a neutron population originating from an ancestor neutron is expressed in the form of the factorial moment expansion, and it is shown how a factorial moment is constructed out of the lower-order moments. The formalism is based on a physical statement that neutrons occupying a certain set of the prescribed space-time points are composed of subgroups which are chain related to the closest common branching point. The statement is found to be a natural extension of Feynman’s derivation of the well-known formula for Variance-to-Mean Ratio Method of measuring reactor noise. The form of the factorial moment expansion of the one-ancestor problem is applied to counting statistics in reactors with random sources. The result turns out to be the factorial cumulant expansion of the probability generating function of count number. It is shown that all the higher factorial cumulants are successively constructed out of the lower orders. New adjoint fields are introduced. It is pointed out that analysis of reactor noise depends on two models of introducing extraneous neutrons into the system, i.e., the random source model and the burst-of-neutrons model.