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This division promotes the development and timely introduction of fusion energy as a sustainable energy source with favorable economic, environmental, and safety attributes. The division cooperates with other organizations on common issues of multidisciplinary fusion science and technology, conducts professional meetings, and disseminates technical information in support of these goals. Members focus on the assessment and resolution of critical developmental issues for practical fusion energy applications.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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First astatine-labeled compound shipped in the U.S.
The Department of Energy’s National Isotope Development Center (NIDC) on March 31 announced the successful long-distance shipment in the United States of a biologically active compound labeled with the medical radioisotope astatine-211 (At-211). Because previous shipments have included only the “bare” isotope, the NIDC has described the development as “unleashing medical innovation.”
V. K. Paré, J. T. Mihalczo
Nuclear Science and Engineering | Volume 56 | Number 2 | February 1975 | Pages 213-218
Technical Note | doi.org/10.13182/NSE75-A26662
Articles are hosted by Taylor and Francis Online.
A theory is developed for the cross-power spectral densities between the signal from an ionization chamber containing a 252Cf neutron source, which provides the initiation of fission chains in a reactor or neutron multiplying assembly, and the signals from detectors of particles from fission chains in the reactor. Previously derived spectral densities between two detectors are modified to include the effects of the inherent and 252Cf source in the reactor. Calculations of the amplitude of the coherence function for noise measurements, both conventional and 252Cf, for the reactor at the Fast Flux Test Facility are presented and can be used to estimate the time required for a measurement with a given precision. The equivalence between the expressions developed here and those previously developed for time-domain measurements of this type is also shown. Use of a 252Cf chamber makes possible a new method of determination of the reactivity which is independent of the inherent source strength and detection efficiency. This method does not require a calibration near delayed criticality as do the previously used methods such as break frequency or coherence amplitude noise analysis and modified source multiplication measurements. It requires the knowledge of some properties of the ionization chamber containing 252Cf which can be determined outside the reactor. Since this method does not require a calibration near delayed criticality, it may be used in the initial loading of a reactor to determine the reactivity before criticality is achieved. The independence of detection efficiency also makes it useful during initial loading, since large changes in detection efficiency can occur with loading. The independence of the method on the inherent source would be advantageous during refueling of a reactor when the inherent source in the fresh fuel inserted may be much less than that of the burnt-up fuel removed. The method may also be useful in determining the reactivity of assemblies where sufficient fuel to achieve criticality is not available.
