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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.
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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
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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.
K. Swaminathan, S. P. Tewari
Nuclear Science and Engineering | Volume 91 | Number 1 | September 1985 | Pages 84-94
Technical Paper | doi.org/10.13182/NSE85-A17130
Articles are hosted by Taylor and Francis Online.
Using thermal neutron scattering kernels suggested for crystalline and noncrystalline polyethylene (PE) various thermal neutron transport processes, such as pulsed neutron, temperature-dependent diffusion length, and temperature- and absorption-dependent steady-state spectra have been studied. The calculated values of the fundamental decay mode in pulsed neutron problems in crystalline PE at 293 K agree with the experimental results of Sjöstrand et al. and Graham and Carpenter for a large buckling range B2 = 0 to ∼ 1.5 cm-2. The time-dependent neutron density for crystalline and amorphous PE is essentially the same and agrees well with the experimental results of Fullwood et al. The propagation of a neutron pulse is therefore independent of the degree of crystallinity of PE. The thermalization time for B2 <1.0 cm-2 is almost constant at ≃12.5 µs. The calculated values of the temperature-dependent diffusion length in crystalline PE in the temperature range from 293 to 400 K agree well with the experimental results of Esch. The computed diffusion lengths in amorphous PE are the same as those in crystalline PE. The space-dependent spectra for different absorptions have also been reported. Steady-state spectra calculations for crystalline PE at 293 K for natural absorption and for absorptions corresponding to 5.74 and 10.45 b/H atom agree well with the experimental results of Young et al. A somewhat detailed study at lower temperatures down to 4 K shows that the effective temperatures of neutron spectra are the same as those at 21K and correspond to 46 K. Thus PE can be a good source of cold neutrons down to 21K, and it is unprofitable to cool it below this temperature to obtain a still larger flux of cold neutrons. The above studies have also been performed on amorphous PE and yield almost the same results as those obtained in crystalline PE. Thus the transport of thermal neutrons is more or less independent of the degree of crystallinity of PE.