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Operations & Power
Members focus on the dissemination of knowledge and information in the area of power reactors with particular application to the production of electric power and process heat. The division sponsors meetings on the coverage of applied nuclear science and engineering as related to power plants, non-power reactors, and other nuclear facilities. It encourages and assists with the dissemination of knowledge pertinent to the safe and efficient operation of nuclear facilities through professional staff development, information exchange, and supporting the generation of viable solutions to current issues.
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ANS Student Conference 2025
April 3–5, 2025
Albuquerque, NM|The University of New Mexico
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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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Latest News
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.”
T. Otsuka, N. Fukumura, Y. Hachiya
Nuclear Science and Engineering | Volume 74 | Number 2 | May 1980 | Pages 95-105
Technical Paper | doi.org/10.13182/NSE80-A19626
Articles are hosted by Taylor and Francis Online.
The moderator temperature coefficients of reactivity for a pressure-tube-type reactor consisting of highly heterogeneous cells with D2O moderator, H2O coolant, and 28-pin fuel cluster contained in a pressure-tube have been measured in order to clarify their dependence on the moderator temperature. A new experimental method has been developed that is applicable to ordinary critical assemblies not equipped with any special temperature control system. In this method, temperature changes of the core, which is subjected to natural cooling that permits heat transfer from the moderator to the H2O coolant, are measured continually, together with the resultant changes in reactivity. The data are analyzed with use of least-squares fitting to nonlinear functions. It has been clarified that the moderator temperature coefficient of reactivity of this type of reactor is markedly dependent on the moderator temperature, decreasing with increase in the temperature. In a clean lattice of 1.2 wt% 235U enriched UO2 fuel that contains no 10B in the moderator, the coefficient changes its sign from positive to negative at ∼40°C. Addition of 3.9 ppm of 10B into the D2O moderator of the same lattice causes the value of the temperature coefficient to shift considerably toward the positive side. Calculational results by the WIMS code reproduce quite well the experimental values of the temperature dependence of the moderator temperature coefficient of reactivity. However, their absolute values are rather small compared to the experimental ones.