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Division Spotlight
Mathematics & Computation
Division members promote the advancement of mathematical and computational methods for solving problems arising in all disciplines encompassed by the Society. They place particular emphasis on numerical techniques for efficient computer applications to aid in the dissemination, integration, and proper use of computer codes, including preparation of computational benchmark and development of standards for computing practices, and to encourage the development on new computer codes and broaden their use.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver 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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Latest News
Argonne’s METL gears up to test more sodium fast reactor components
Argonne National Laboratory has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop), the Department of Energy announced April 23. The upgrade is the first of its kind in the United States in more than 30 years, according to the DOE, and will help test components and operations for the sodium-cooled fast reactors being developed now.
Keiichi Saito
Nuclear Science and Engineering | Volume 37 | Number 3 | September 1969 | Pages 380-396
Technical Paper | doi.org/10.13182/NSE69-A19114
Articles are hosted by Taylor and Francis Online.
Input-noise sources in at-power reactors are formulated under the basic assumption that a set of macrostochastic variables characterizing the state of the reactors has Markoffian properties. An input-noise source is defined as the ratio between the power-spectral density of fluctuations in the reactor-power level and the square modulus of the source-transfer function. Random birth and death processes of neutrons give rise to a “white” contribution to the input source. Additional contributions are found which have the break (roll-off) angular frequencies determined by the relaxation time constants of the feedback effects on reactivity. These “non-white” terms come from fluctuations in neutron-reaction cross sections caused by temperature variations. The ratio of the non-white to the white terms increases as the reactor power increases. It also depends on the magnitude of the reactivity coefficients of feedback. Before one evaluates the magnitude of the non-white noise term, however, there should be knowledge of some statistical parameters relating the noise to random emission of energy by nuclear fissions, random exchange between the fuel and the coolant in heat transfer reactions and random removal through the coolant flow. The formula for analyzing the power-spectral density of the temperature fluctuations is also derived where the same unknown statistical parameters appear. Measurements of both the power and the temperature fluctuations will serve to determine these parameters whereby one will be able to obtain better information on the time constant and the reactivity coefficient of each feedback effect.