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
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
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.”
Robert C. Ward, Randal S. Baker, Jim E. Morel
Nuclear Science and Engineering | Volume 152 | Number 2 | February 2006 | Pages 164-179
Technical Paper | doi.org/10.13182/NSE06-A2573
Articles are hosted by Taylor and Francis Online.
A multidimensional block-based adaptive mesh refinement (BAMR) method for the neutral particle transport equation with diamond and linear discontinuous spatial differencing was developed several years ago. This method was implemented in the PARallel TIme-dependent SN (PARTISN) deterministic transport code. However, the only source acceleration method available with BAMR was transport synthetic acceleration. Although the block-based adaptive mesh is orthogonal, the individual mesh cells may not be simply connected. Because of this lack of simple connectivity, development of a fully consistent diffusion synthetic acceleration (DSA) method has not been possible. This paper describes the development of a DSA method based upon an additive correction to the scalar flux iterate after a transport sweep. This DSA equation is differenced using a vertex-centered diffusion discretization that is diamond-like and may be characterized as "partially" consistent. It does not appear algebraically possible to derive a diffusion discretization that is fully consistent with diamond transport differencing on AMR meshes. The diffusion matrix is symmetric positive definite, and the DSA method is effective for most applications. This BAMR-DSA solver has been implemented and tested in two dimensions for rectangular (X-Y) and cylindrical (R-Z) geometries. As expected, results confirm that a partially consistent BAMR-DSA method will introduce instabilities for extreme cases (e.g., scattering ratios approaching 1.0 with optically thick cells), but for most realistic problems, e.g., the iron-water shielding problem, the BAMR-DSA method provides an effective acceleration method.