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2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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Nano to begin drilling next week in Illinois
It’s been a good month for Nano Nuclear in the state of Illinois. On October 7, the Office of Governor J.B. Pritzker announced that the company would be awarded $6.8 million from the Reimagining Energy and Vehicles in Illinois Act to help fund the development of its new regional research and development facility in the Chicago suburb of Oak Brook.
Chester D. Kylstra and Robert E. Uhrig
Nuclear Science and Engineering | Volume 22 | Number 2 | June 1965 | Pages 191-205
Technical Paper | doi.org/10.13182/NSE65-A20238
Articles are hosted by Taylor and Francis Online.
The concept of a transfer function for a nuclear system is extended to include spatial effects. The general equation is derived using the time-dependent Fermi age and diffusion theories for a single-region, isotropic, homogeneous medium. The fluctuations of the thermal-neutron density at any point in the assembly is related to the variation of the fast-neutron source. The general transfer function equation is specialized for several cases, including the case of a point source in a cylindrical medium. Theoretical curves are calculated for multiplying and non-multiplying media and compared with the commonly used lumped-parameter transfer function. The results indicate, in general, that the lumped-parameter model predicts the correct behavior of the nuclear system only if the output detector is carefully positioned at a specific distance from the source. If the detector is located elsewhere, the lumped-parameter model is not capable of accurate results. The theoretical equations were used to calculate the spatially dependent transfer function between two detectors (the cross-transfer function) that were located within light- and heavy-water subcritical assemblies, simulating some experimental measurements. A comparison of the experimental and theoretical transfer functions indicate that the Fermi age, diffusion theory model might be quite adequate in describing the kinetics of a nuclear system.