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
Mathematics & Computation
Division members promote the advancement of mathematical and computational methods for solving problems arising in all disciplines encompassed by the Society. They place particular emphasis on numerical techniques for efficient computer applications to aid in the dissemination, integration, and proper use of computer codes, including preparation of computational benchmark and development of standards for computing practices, and to encourage the development on new computer codes and broaden their use.
Meeting Spotlight
ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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
Apr 2025
Jan 2025
Latest Journal Issues
Nuclear Science and Engineering
May 2025
Nuclear Technology
April 2025
Fusion Science and Technology
Latest News
General Kenneth Nichols and the Manhattan Project
Nichols
The Oak Ridger has published the latest in a series of articles about General Kenneth D. Nichols, the Manhattan Project, and the 1954 Atomic Energy Act. The series has been produced by Nichols’ grandniece Barbara Rogers Scollin and Oak Ridge (Tenn.) city historian David Ray Smith. Gen. Nichols (1907–2000) was the district engineer for the Manhattan Engineer District during the Manhattan Project.
As Smith and Scollin explain, Nichols “had supervision of the research and development connected with, and the design, construction, and operation of, all plants required to produce plutonium-239 and uranium-235, including the construction of the towns of Oak Ridge, Tennessee, and Richland, Washington. The responsibility of his position was massive as he oversaw a workforce of both military and civilian personnel of approximately 125,000; his Oak Ridge office became the center of the wartime atomic energy’s activities.”
Kazuyoshi Hada, Kazunobu Nagasaki, Kai Masuda, Shinji Kobayashi, Shunsuke Ide, Akihiko Isayama, Ken Kajiwara
Fusion Science and Technology | Volume 67 | Number 4 | May 2015 | Pages 693-704
Technical Paper | doi.org/10.13182/FST14-811
Articles are hosted by Taylor and Francis Online.
By using a one-dimensional model, we analyze plasma start-up assisted by second-harmonic extraordinary-mode electron cyclotron (EC) resonance heating (ECRH). The model leads to energy transport equations for electrons and ions, particle transport equations for electrons and hydrogen atoms, and a toroidal current equation. These equations are solved for a cylindrically symmetrical plasma; that is, a torus straightened to a cylinder with a circular cross section and on-axis ECRH power absorption. The calculation indicates that ECRH has a threshold power for plasma start-up in JT-60SA. For example, approximately 1 MW of ECRH power is required for plasma start-up for an initial hydrogen atom density nH(t=0) = 3.0 × 1018 m-3, an error field Berr = 1 mT, carbon and oxygen impurity fractions nc/ne = no/ne = 0.1%, and an EC beam radius of approximately 5 cm. This estimated ECRH power is less than the planned power and increases sublinearly with the initial hydrogen atom density. The threshold power depends weakly on the error field and carbon impurity concentration. This is especially prominent for plasma start-up with a low initial hydrogen atom density. This result implies that suppressing the error field and carbon impurity density is helpful for reliable plasma start-up.