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
Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
Meeting Spotlight
Conference on Nuclear Training and Education: A Biennial International Forum (CONTE 2025)
February 3–6, 2025
Amelia Island, FL|Omni Amelia Island Resort
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
Jan 2025
Jul 2024
Latest Journal Issues
Nuclear Science and Engineering
February 2025
Nuclear Technology
January 2025
Fusion Science and Technology
Latest News
When your test capsule is the test: ORNL’s 3D-printed rabbit
Oak Ridge National Laboratory has, for the first time, designed, printed, and irradiated a specimen capsule—or rabbit capsule—for use in its High Flux Isotope Reactor (HFIR), the Department of Energy announced on January 15.
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.
