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Division Spotlight
Decommissioning & Environmental Sciences
The mission of the Decommissioning and Environmental Sciences (DES) Division is to promote the development and use of those skills and technologies associated with the use of nuclear energy and the optimal management and stewardship of the environment, sustainable development, decommissioning, remediation, reutilization, and long-term surveillance and maintenance of nuclear-related installations, and sites. The target audience for this effort is the membership of the Division, the Society, and the public at large.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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!
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Latest News
Ariz. governor vetoes “fast track” bill for nuclear
Gov. Katie Hobbs put the brakes on legislation that would have eliminated some of Arizona’s regulations and oversight of small modular reactors, technology that is largely under consideration by data centers and heavy industrial power users.
Feroz Ahmed, L. S. Kothari, Ashok Kumar
Nuclear Science and Engineering | Volume 46 | Number 2 | November 1971 | Pages 203-213
Technical Paper | doi.org/10.13182/NSE71-A22354
Articles are hosted by Taylor and Francis Online.
The dependence of neutron diffusion length on the size and shape of the cross-sectional area of infinitely long rectangular blocks of crystalline moderators (graphite and beryllium) has been studied using an energy-dependent transverse buckling. In conformity with the experimental results in graphite, the diffusion length is found to increase with a decrease in the transverse size of the assembly. It is further found that in assemblies with small transverse dimensions, pseudoequilibrium conditions are established fairly rapidly and reasons for this are discussed. On the other hand, in assemblies with intermediate transverse dimensions (cross-sectional area lying between 70 × 70 cm2 and 50 × 50 cm2 for graphite and between 30 × 30 cm2 and 20 × 20 cm2 for beryllium), even pseudo-equilibrium conditions are not established at very large distances from the source. Dependence of the diffusion length on the shape of the cross-sectional area is also investigated.
