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
Nuclear Criticality Safety
NCSD provides communication among nuclear criticality safety professionals through the development of standards, the evolution of training methods and materials, the presentation of technical data and procedures, and the creation of specialty publications. In these ways, the division furthers the exchange of technical information on nuclear criticality safety with the ultimate goal of promoting the safe handling of fissionable materials outside reactors.
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.”
Yassin A. Hassan, Hagop R. Barsamian
Nuclear Technology | Volume 128 | Number 1 | October 1999 | Pages 58-74
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT99-A3014
Articles are hosted by Taylor and Francis Online.
The dynamic subgrid-scale (DSGS) closure model is used in a large eddy simulation computer program for incompressible isothermal flows. One of the advantages of the DSGS model is the exclusion of a model coefficient. This model coefficient is evaluated dynamically at each nodal location for a given time step by filtering operations on the grid level and a test filter level. A nonstaggered array tube bundle geometry arrangement is considered in doubly periodic boundary conditions for two-dimensional simulations at high Reynolds number. Results of the DSGS simulation are obtained in the form of power spectral densities and visualization of flow characteristics. The DSGS model simulation results are compared to the Smagorinsky eddy viscosity model simulation and available experimental data. The DSGS model simulation is found to be in good agreement with spectral data available from experiments in similar bundle arrangements. Coherent eddy structures were observed. Body forces acting on the tubes showed satisfactory characteristics. Integral length and timescales are evaluated using correlation functions that describe the turbulence structure. The applicability of large eddy simulation to complex engineering flow situations has been shown using the DSGS model with applications to steam generator bundles for understanding of flow-induced vibration problems revealing the physical phenomena of the flow.