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Division Spotlight
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
2024 ANS Winter Conference and Expo
November 17–21, 2024
Orlando, FL|Renaissance Orlando at SeaWorld
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
Young nuclear advocates “get in the game” this college football season
Nuclear advocates across the country have been asking fans to cheer for more than just touchdowns this college football season. They want people to learn about and support nuclear energy.
They want them to “heart” nuclear as much as they do.
D. R. Bach, S. I. Bunch, R. J. Cerbone, R. E. Slovacek
Nuclear Science and Engineering | Volume 11 | Number 2 | October 1961 | Pages 199-210
Technical Paper | doi.org/10.13182/NSE61-A28065
Articles are hosted by Taylor and Francis Online.
Prompt neutron decay constants have been measured for a series of polyethylene moderated subcritical assemblies. Values of keff varying between 0.20 and 1.0 were obtained by changing the physical size rather than by changing the poison concentration. The decay constants, as determined by the 1/v poison removal method, in a four-group diffusion calculation employing a group dependent buckling, agree to within 10% of the measured values. Preliminary integral type measurements of the neutron spectrum which exists in the assembly during the persistent spatial mode decay indicate that the spectrum is extremely “diffusion cooled.” A simple two-group calculation shows that the decay constant in a subcritical system is proportional to the difference of two spectra. The first is the spectrum which would exist in the assembly when excited by a time independent high energy source; the second is the spectrum existing in the assembly during the persistent mode decay of the neutron density. The conventional description of far-subcritical systems in terms of reactivity is tenuous because of the lack of well defined experiments for its determination. It is apparently more useful to characterize a far-subcritical system by its decay constant, which is directly observable.