ANS is committed to advancing, fostering, and promoting the development and application of nuclear sciences and technologies to benefit society.
Explore the many uses for nuclear science and its impact on energy, the environment, healthcare, food, and more.
Division Spotlight
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
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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May 2025
Nuclear Technology
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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.
S. Bian
Nuclear Technology | Volume 41 | Number 3 | December 1978 | Pages 401-407
Technical Note | Reactor | doi.org/10.13182/NT78-A32124
Articles are hosted by Taylor and Francis Online.
A rod ejection accident introduces a large positive reactivity insertion in a core, causing a large power excursion. The point kinetics method is usually used to analyze this type of accident. The reactivity changes due to Doppler effect are usually obtained by static neutronics calculations with nominal (pre-ejection) core flux shapes for different fuel temperatures. The effect of locally peaked shapes due to the rod ejection is not included in the Doppler reactivity calculation. The resultant Doppler reactivity feedback is considerably underestimated, while the magnitude of the power excursion is overestimated. A simplified method that incorporates the local flux peaking effect on the Doppler feedback in a point kinetics code has been developed. The results based on this weighted Doppler feedback compare favorably with a three-dimensional kinetics analysis.