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Fusion Energy
This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
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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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.
R. A. Bennett
Nuclear Science and Engineering | Volume 17 | Number 1 | September 1963 | Pages 131-143
Technical Paper | doi.org/10.13182/NSE63-A17218
Articles are hosted by Taylor and Francis Online.
Integral experiments have been conducted to study rethermalization in moderating media having temperature discontinuities. Neutron absorption rates of Cu63, Au197, and Lu176 have been observed near these discontinuities in the temperatures of concentric annuli of graphite and of water and graphite systems. For this report the data have been analyzed with a two-thermal-group diffusion model of the space and energy distribution of the thermal neutrons. Cross sections and relaxation distances for neutron rethermalization in water and graphite have been inferred from the analyses. These rethermalization cross sections are integral representations of the scattering kernel. The relaxation distances were found to be shorter for the rethermalization of cold neutrons in warm graphite than for the rethermalization of warm neutrons in cold graphite. The cross section of hot graphite for rethermalization of 300°K neutrons increases monotonically to near the free gas value, 0.0614 cm−1, as the graphite temperature increases to 850°K. The cross section of 300°K graphite for rethermalization of 850°K neutrons is well below the free gas value, in agreement with theoretical calculations. Within the limits of the heavy gas model one can define an effective mass in terms of the rethermalization cross section. Effective masses of graphite reported here are comparable with those inferred by others from lattice-spectrum measurements. The rethermalization cross sections of 300°K water presented here yield effective masses of the water molecule that lie in the range of 4.1 to 7.2 amu for 410 to 720°K neutrons, respectively.