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.”
Toshiso Kosako, Junpei Matsumoto, Akira Sekiguchi+, Nobuo Ohtani, Soju Suzuki, Shinso Takeda, Osamu Sato
Nuclear Technology | Volume 77 | Number 3 | June 1987 | Pages 279-294
Technical Paper | Nuclear Safety | doi.org/10.13182/NT87-A33967
Articles are hosted by Taylor and Francis Online.
To investigate the neutron dose and spectra around a fast reactor from the point of view of radiation protection and shielding, neutron measurements were conducted at the reactor top of JOYO, a Japanese experimental fast reactor, and an analysis by a transport calculation was performed. The measurements were carried out under a Mark II irradiation core with and without the reactor top concrete pit cover at 98- and 48-MW(thermal) power levels, respectively. The measurements were performed at several points in and around the reactor top pit room. Neutron detectors with well-examined response functions were employed for this study—the rem (sievert) counter as a neutron dosimeter and the multimoderator neutron detector as a neutron spectrometer. The measured neutron doses distributed from 0.4 to 100 mrem/h·[100 MW(thermal)]−1 {4 to 1000 μSv/h· [100 MW(thermal)]−1 } and the measured neutron spectra showed an ∼1/E type energy distribution. The rapid spatial change of the neutron spectrum could not be observed near the reactor top. The neutron flux distributions around the reactor were calculated and compared with the measured results. The two-dimensional transport code DOT 3.5 was employed for the calculation, and the neutron group constants were prepared by using JENDL-2 cross-section libraries. The values of measurements and calculations were in relatively good agreement within a factor of 3 to 5 in spite of the 12-decade decrease in neutron flux from the reactor core center. It is shown that the effect of stored fuels in invessel storage racks has greatly affected the neutron dose rate at the reactor top. The modeling for shielding calculations of the iron rotating plug structures is discussed.