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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
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
TerraPower begins U.K. regulatory approval process
Seattle-based TerraPower signaled its interest this week in building its Natrium small modular reactor in the United Kingdom, the company announced.
TerraPower sent a letter to the U.K.’s Department for Energy Security and Net Zero, formally establishing its intention to enter the U.K. generic design assessment (GDA) process. This is TerraPower’s first step in deployment of its Natrium technology—a 345-MW sodium fast reactor coupled with a molten salt energy storage unit—on the international stage.
W. R. Waltz, J. F. Walter
Nuclear Technology | Volume 10 | Number 2 | February 1971 | Pages 160-167
Technical Paper and Note | Reactor | doi.org/10.13182/NT71-A30923
Articles are hosted by Taylor and Francis Online.
Comparisons of calculation and experiment have been performed to test the adequacy of fewgroup subcritical diffusion theory in predicting neutron detector response induced from material changes in a subcritical water-moderated reactor. In many operations involving material changes in a subcritical reactor, it is desired to monitor changes in the multiplication factor (Keff) of the system to ensure the safety of an operation by avoiding an accidental close approach to criticality. This monitoring procedure is accomplished by the introduction of artificial neutron sources to the system and by the proper interpretation of changes in neutron detector readings in terms of Keff. Because of the rather complicated involvement of the source-core-detector system, proper interpretation of detector response observed during these operations can only be achieved by the availability to predict detector response obtained from an accurate calculational model. Comparisons of calculation to experiment show that diffusion theory may be used successfully for these purposes; however, certain limitations of the model must be recognized and avoided. The breakdown of the calculational model in certain cases can be related ultimately to the inability of few-group diffusion theory to predict the absolute magnitude of detector flux for large distances through a water (or metal-water) shield. This inability can result in inaccuracies in predicted count rate response when applied to a specific source-core-detector arrangement with the characteristic that a given material change results in gross changes in the axial flux distribution. These effects can be overcome by the suitable positioning of the neutron source and detector relative to the subcritical assembly.
