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
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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
Jul 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
September 2025
Nuclear Technology
August 2025
Fusion Science and Technology
Latest News
Deep Space: The new frontier of radiation controls
In commercial nuclear power, there has always been a deliberate tension between the regulator and the utility owner. The regulator fundamentally exists to protect the worker, and the utility, to make a profit. It is a win-win balance.
From the U.S. nuclear industry has emerged a brilliantly successful occupational nuclear safety record—largely the result of an ALARA (as low as reasonably achievable) process that has driven exposure rates down to what only a decade ago would have been considered unthinkable. In the U.S. nuclear industry, the system has accomplished an excellent, nearly seamless process that succeeds to the benefit of both employee and utility owner.
Shin Nishimura, Hideo Sugama, CHS Group
Fusion Science and Technology | Volume 46 | Number 1 | July 2004 | Pages 77-81
Technical Paper | Stellarators | doi.org/10.13182/FST04-A542
Articles are hosted by Taylor and Francis Online.
A recently developed method to calculate the neoclassical viscosity, diffusion, and current coefficients in general nonsymmetric toroidal plasmas by using the direct solution of the linearized drift kinetic equation with the pitch-angle-scattering collision operator is applied to impurity transport problems and bootstrap current calculations in stellarators. In this new method based on the basic idea of the so-called moment approach, the collisional momentum conservation is taken into account, and thus, it is applicable to the heat and particle diffusivity in advanced stellarators with quasi symmetry, and also to plasma flows currents, and viscosities in general nonsymmetric multispecies plasmas. In this paper, the impurity flow and the bootstrap current observed in the neoclassical internal transport barrier operation in the Compact Helical System are compared with theoretical calculations. Another topic is the benchmark test of existing analytical expressions for the bootstrap currents by comparing with numerically obtained current coefficients. The geometric factor, which is required for the current calculation based on the moment method, given by our new method is compared with these formulas.