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Conference Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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!
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Powering the future: How the DOE is fueling nuclear fuel cycle research and development
As global interest in nuclear energy surges, the United States must remain at the forefront of research and development to ensure national energy security, advance nuclear technologies, and promote international cooperation on safety and nonproliferation. A crucial step in achieving this is analyzing how funding and resources are allocated to better understand how to direct future research and development. The Department of Energy has spearheaded this effort by funding hundreds of research projects across the country through the Nuclear Energy University Program (NEUP). This initiative has empowered dozens of universities to collaborate toward a nuclear-friendly future.
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.
