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 Nonproliferation Policy
The mission of the Nuclear Nonproliferation Policy Division (NNPD) is to promote the peaceful use of nuclear technology while simultaneously preventing the diversion and misuse of nuclear material and technology through appropriate safeguards and security, and promotion of nuclear nonproliferation policies. To achieve this mission, the objectives of the NNPD are to: Promote policy that discourages the proliferation of nuclear technology and material to inappropriate entities. Provide information to ANS members, the technical community at large, opinion leaders, and decision makers to improve their understanding of nuclear nonproliferation issues. Become a recognized technical resource on nuclear nonproliferation, safeguards, and security issues. Serve as the integration and coordination body for nuclear nonproliferation activities for the ANS. Work cooperatively with other ANS divisions to achieve these objective nonproliferation policies.
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
Fusion Science and Technology
Latest News
General Atomics tests fuel as space nuclear propulsion R&D powers on
General Atomics Electromagnetic Systems (GA-EMS) has announced that it has subjected nuclear thermal propulsion (NTP) fuel samples to several “high-impact” tests at NASA’s Marshall Space Flight Center (MSFC) in Huntsville, Ala. That news comes as NASA, the Department of Defense, the Department of Energy, and multiple nuclear and space technology companies continue to build on recent progress in nuclear thermal rocket design and demonstration.
M. M. R. Williams
Nuclear Science and Engineering | Volume 141 | Number 1 | May 2002 | Pages 13-31
Technical Paper | doi.org/10.13182/NSE02-A2263
Articles are hosted by Taylor and Francis Online.
A method has been developed for calculating the probability distribution of the multiplication factor in a system in which the fissile or absorbing elements are randomly distributed across the core and can have random material properties. It has practical applications to the storage of radioactive waste in drums in which fissile material is stored in a background matrix. The procedure is based upon the source-sink method of heterogeneous reactors developed by Feinberg, Galanin, Horning and Stewart in which the fuel element or absorber is replaced by a point sink of thermal neutrons and a point source of fast neutrons. The positions and material properties are sampled from a random distribution and a probability distribution is built up for the multiplication factor keff. Calculations are made for spheres in a cubic system and probability distributions, mean values and variances are obtained for 1, 2, 3, 5, 10 and 25 spheres in both water and graphite moderated systems. Some interesting fine structure is found in the probability distributions which is attributed to preferred symmetric groupings of the spheres in the lattice. We also examine the effect of small random movements of the spheres about their mean positions and in particular study the effect of anisotropy of motion, i.e. perpendicular to the plane and in the plane, on the mean value of the multiplication factor and the associated probability distributions. Some experimental results obtained by Lloyd on reactivity changes in random lattices are examined and qualitative agreement is obtained. A convenient form of the three dimensional Greens function for a rectangular box is developed which is especially useful for numerical purposes due to its rapid convergence properties.
