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Division Spotlight
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.
Meeting Spotlight
Conference on Nuclear Training and Education: A Biennial International Forum (CONTE 2025)
February 3–6, 2025
Amelia Island, FL|Omni Amelia Island Resort
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
IEA report: Challenges need to be resolved to support global nuclear energy growth
The International Energy Agency published a new report this month outlining how continued innovation, government support, and new business models can unleash nuclear power expansion worldwide.
The Path to a New Era for Nuclear Energy report “reviews the status of nuclear energy around the world and explores risks related to policies, construction, and financing.”
Find the full report at IEA.org.
G. R. Pflasterer, Jr., R. Sher
Nuclear Science and Engineering | Volume 30 | Number 3 | December 1967 | Pages 374-394
Technical Paper | doi.org/10.13182/NSE67-A18400
Articles are hosted by Taylor and Francis Online.
The Doppler effect in 238U capture and 235U fission has been measured by means of a foil activation technique in the fast-neutron spectrum core of the Mixed Spectrum Critical Assembly. Experimental results were obtained for two 238U foil thicknesses and one 235U foil thickness. The amount of scattering material between the foil and surrounding core fuel was varied to determine the effect on the Doppler measurement of change in the incident flux fine-energy structure in the resonances. In this experiment, only the foil is heated, while the core fuel remains at room temperature. The experiment is analyzed by means of the collision-probability method which is used to develop an expression for the resonance integral of a thin absorber which is separated from a homogeneous reactor fuel region by a purely scattering medium. The general expression for the foil resonance integral is simplified and numerical results are presented for the case in which the dominant resonances are weak; that is, for a fast reactor in which the 0.5 to 3.0-keV energy region dominates the 238U Doppler effect. The measured 238U Doppler effect expressed as the ratio typically was of the order of 0.015 ±0.002. This was a factor of 2 higher than that calculated using a neutron energy spectrum derived from “nominal” material cross sections. Presently available cross sections in the energy range of interest are sufficiently uncertain so that it is possible to infer from them “hard” or “soft” neutron energy spectra such that the value oi R-l varies by a factor of 2. The measured values for 238U agreed quantitatively with those found from the “soft” neutron energy spectrum. Within the precision of the measurement no 235U Doppler effect was observed. The calculated 235U Doppler effect was smaller than the sensitivity of the experiment, thus, within its precision (± 0.002), the measurement confirms the theory.