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.
Explore membership for yourself or for your organization.
Conference Spotlight
2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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!
Latest Magazine Issues
Oct 2025
Jul 2025
Latest Journal Issues
Nuclear Science and Engineering
November 2025
Nuclear Technology
October 2025
Fusion Science and Technology
Latest News
NRC nominee Nieh commits to independent safety mission
During a Senate Environment and Public Works Committee hearing today, Ho Nieh, President Donald Trump’s nominee to serve as a commissioner at the Nuclear Regulatory Commission, was urged to maintain the agency’s independence regardless of political pressure from the Trump administration.
F. Warmer, C. D. Beidler, A. Dinklage, Y. Turkin, R. Wolf
Fusion Science and Technology | Volume 68 | Number 4 | November 2015 | Pages 727-740
Technical Paper | doi.org/10.13182/FST15-131
Articles are hosted by Taylor and Francis Online.
In fusion power plant studies, a high confinement improvement with respect to empirical scaling is often assumed in the design of compact machines. In this work, the limits of such a confinement enhancement are studied for a helical-axis advanced stellarator (HELIAS).
As a first exercise, the well-established power balance approach is used to investigate the impact of confinement enhancement (in terms of the ISS04 renormalization factor) on the required size of HELIAS power plants. It is found that both a lower (0.5) and an upper limit (1.5 to 1.7) exist for which, respectively, ignition is no longer possible or further confinement enhancement irrelevant due to physics limits.
In the second part of the work, a predictive neoclassical transport model is introduced and employed to determine a self-consistent confinement time based on transport modelling. It is found that the confinement enhancement with respect to the ISS04 scaling decreases in comparison to Wendelstein 7-X as the device is scaled to reactor size, dropping from ~2.5 to a range of 1.2 to 1.3. This behavior is explained with underlying scaling relations and transport effects. The results from both models are consistent and important for future HELIAS systems studies.