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Radiation Protection & Shielding
The Radiation Protection and Shielding Division is developing and promoting radiation protection and shielding aspects of nuclear science and technology — including interaction of nuclear radiation with materials and biological systems, instruments and techniques for the measurement of nuclear radiation fields, and radiation shield design and evaluation.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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!
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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.”
Mathieu Martin, Daniel Leonard, R. Brian Jackson, K. Michael Steer
Nuclear Technology | Volume 206 | Number 9 | September 2020 | Pages 1325-1336
Technical Paper | doi.org/10.1080/00295450.2020.1727263
Articles are hosted by Taylor and Francis Online.
TerraPower participated in a cooperative project among industry, a national laboratory, and a university to perform verification and validation of computational fluid dynamics (CFD) methods for predicting the flow and heat transfer within fuel assemblies with hexagonally packed wire-wrapped fuel pins. This project consisted of both experimental and numerical components and used surrogate fluids and electrically heated fuel pins to substitute for liquid metal and nuclear fuel. TerraPower performed CFD simulations of the experiments using industrial-level Reynolds-averaged Navier-Stokes (RANS) turbulence modeling. These simulations of helically wire-wrapped fuel assemblies employed meshes of bare pins without the wire-wrap geometry explicitly modeled. Instead, the effect of the wire-wrap on the flow is accounted for by introducing a momentum source (MS) into the governing fluid equations.
Solution validation was conducted by benchmarking the CFD simulations to the heated bundle experiments. These simulations used the as-tested boundary and operating conditions but were conducted blind. Pressure drop measurements and local temperature measurements were compared.
Axial pressure drop simulation results compared well with the experiment measurements. The vast majority of the local CFD temperatures matched thermocouple measurements within the instrument uncertainty. The good agreement between simulation and experiment supports the use of RANS-based CFD simulation methods and the specific applied MS method to model wire-wrapped fuel assemblies.