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September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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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.
Mikdam Saleh, R. A. Danofsky, R. A. Hendrickson
Nuclear Science and Engineering | Volume 80 | Number 1 | January 1982 | Pages 179-184
Technical Note | doi.org/10.13182/NSE82-A21414
Articles are hosted by Taylor and Francis Online.
A number of investigators have discussed the use of two-detector cross power spectral density (CPSD) measurements to obtain the velocity of an axially propagating perturbation of the moderator density in a boiling water reactor. The basis of the measurements is the view that the detector response can be separated into local and global components where the local component, which is dominant for high frequencies (f > 2 Hz), makes possible the observation of the moving perturbation associated with steam flow in the reactor. For low frequencies, the response consists of a combination of the local and global components, and correlation with the perturbation velocity is not straightforward. In this Note, the asymptotic low and high frequency behavior of the CPSD is examined using the complex detector adjoint function formulation. It is shown that at low frequencies, where the wavelength of the perturbation is much larger than the axial core dimension, the phase of the CPSD and therefore the perturbation velocity correlates with the centroid spacing of detector functions involving the product of the detector adjoint function and the static flux. For high frequencies, on the other hand, the phase correlates with the detector spacing. This behavior is considered to be an alternate manifestation of the local/global concept. Numerical calculations based on a two-group, one-dimensional model are used to illustrate these observations. It is also shown using the model that the oscillations in the phase in the intermediate frequency range disappear for frequencies that correspond to wavelengths that are intergral multiples of the core height.