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.”
S. Bourganel, O. Petit, C. M. Diop
Nuclear Technology | Volume 184 | Number 1 | October 2013 | Pages 29-41
Technical Paper | Neutron Transport and Shielding | doi.org/10.13182/NT13-A19866
Articles are hosted by Taylor and Francis Online.
The Électricité de France nuclear park consists of 58 pressurized water nuclear reactors. To ensure their good performance and safety, ex-core neutron shielding studies are regularly performed. For example, neutron flux calculations in ex-core ionization chambers and pressure vessel neutron fluence studies are carried out. In the first case, ex-core ionization chambers are neutron detectors located in the reactor pit, around the reactor vessel. They are dedicated to reactor operation and core protection. In the second case, the calculation of the fast fluence (for energy >1 MeV) in the pressure vessel is used to determine its fracture toughness and integrity. To improve the fluence computations, new efficient parametric methods are under development. For these two problems, Monte Carlo transport codes such as TRIPOLI-4® allow us to perform simulations in realistic complex three-dimensional geometries and to produce reference results.The aim of the present paper is to present together the theoretical background of our approach based on the continuous-energy Green's functions computation and storage to perform both vessel neutron fluence and ex-core chamber responses. The normalized source contribution or importance factor formalism using Green's functions computation is also described, with its associated statistical uncertainty calculation. Application examples to realistic nuclear plant configurations are given.
