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Division Spotlight
Young Members Group
The Young Members Group works to encourage and enable all young professional members to be actively involved in the efforts and endeavors of the Society at all levels (Professional Divisions, ANS Governance, Local Sections, etc.) as they transition from the role of a student to the role of a professional. It sponsors non-technical workshops and meetings that provide professional development and networking opportunities for young professionals, collaborates with other Divisions and Groups in developing technical and non-technical content for topical and national meetings, encourages its members to participate in the activities of the Groups and Divisions that are closely related to their professional interests as well as in their local sections, introduces young members to the rules and governance structure of the Society, and nominates young professionals for awards and leadership opportunities available to members.
Meeting Spotlight
Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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
DOE extends Centrus’s HALEU production contract by one year
Centrus Energy has announced that it has secured a contract extension from the Department of Energy to continue—for one year—its ongoing high-assay low-enriched uranium (HALEU) production at the American Centrifuge Plant in Piketon, Ohio, at an annual rate of 900 kilograms of HALEU UF6. According to Centrus, the extension is valued at about $110 million through June 30, 2026.
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.