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
Aerospace Nuclear Science & Technology
Organized to promote the advancement of knowledge in the use of nuclear science and technologies in the aerospace application. Specialized nuclear-based technologies and applications are needed to advance the state-of-the-art in aerospace design, engineering and operations to explore planetary bodies in our solar system and beyond, plus enhance the safety of air travel, especially high speed air travel. Areas of interest will include but are not limited to the creation of nuclear-based power and propulsion systems, multifunctional materials to protect humans and electronic components from atmospheric, space, and nuclear power system radiation, human factor strategies for the safety and reliable operation of nuclear power and propulsion plants by non-specialized personnel and more.
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
First astatine-labeled compound shipped in the U.S.
The Department of Energy’s National Isotope Development Center (NIDC) on March 31 announced the successful long-distance shipment in the United States of a biologically active compound labeled with the medical radioisotope astatine-211 (At-211). Because previous shipments have included only the “bare” isotope, the NIDC has described the development as “unleashing medical innovation.”
T. M. John, Om Pal Singh
Nuclear Science and Engineering | Volume 85 | Number 4 | December 1983 | Pages 362-370
Technical Paper | doi.org/10.13182/NSE83-A18383
Articles are hosted by Taylor and Francis Online.
The results of a theoretical study of noise transmission characteristics of multiplying media and neutron noise source localization in liquid-metal fast breeder reactors (LMFBRs) by using the neutron wave propagation technique is reported. The study was carried out using one-group as well as multigroup diffusion theory. Both theories show that the noise transmission characteristics are quite sensitive to the multiplication factor k of the medium. For k very close to unity, the response of the out-of-core detectors is found to be the same irrespective of the location of the neutron noise source in the multiplying medium. However, for a highly subcritical reactor, the response of the out-of-core detectors is sensitive to the location of the neutron noise source, and from the point of view of the noise transmission characteristics, the medium behaves like a nonmultiplying medium. The analytical results of one-group theory that are fully supported by the multigroup multiregion theory clearly indicate that the neutron noise signal at detector locations can be assumed to be made up of two components—the first (local) is insensitive to the multiplication factor, and the second (global) is very sensitive to the multiplication factor of the system. If the local component can be separated from the total out-of-core detector signal, then a proper calibration of the local component with respect to the various locations of neutron noise source may help in finding the location of the neutron noise source in LMFBR cores. Further, it is observed that, as in the case of nonmultiplying media, noise transmission through largely subcritical multiplying media occurs with equal attenuation for all frequencies w < (υ∑t)min, where υ is the speed of the neutrons and ∑t is the total removal cross section, and for w > (υ ∑,t)min, the attenuation increases with frequency. However, for a critical system, the global component in a multiplying medium is maximum at lower frequencies and decreases rapidly for higher frequencies, and the local component remains the same as in the case of largely subcritical systems.
