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.
Explore membership for yourself or for your organization.
Conference Spotlight
2026 ANS Annual Conference
May 31–June 3, 2026
Denver, CO|Sheraton Denver
Latest Magazine Issues
Apr 2026
Jan 2026
Latest Journal Issues
Nuclear Science and Engineering
June 2026
Nuclear Technology
March 2026
Fusion Science and Technology
May 2026
Latest News
DOE selects first companies for nuclear launch pad
The Department of Energy’s Office of Nuclear Energy and the National Reactor Innovation Center have announced their first selections for the Nuclear Energy Launch Pad: three companies developing microreactors and one developing fuel supply.
The four companies—Deployable Energy, General Matter, NuCube Energy, and Radiant Industries—were selected from the initial pool of Reactor Pilot Program and Fuel Line Pilot Program applicants, the two precursor programs to the launch pad.
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.
