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Reactor Physics
The division's objectives are to promote the advancement of knowledge and understanding of the fundamental physical phenomena characterizing nuclear reactors and other nuclear systems. The division encourages research and disseminates information through meetings and publications. Areas of technical interest include nuclear data, particle interactions and transport, reactor and nuclear systems analysis, methods, design, validation and operating experience and standards. The Wigner Award heads the awards program.
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2025 ANS Annual Conference
June 15–18, 2025
Chicago, IL|Chicago Marriott Downtown
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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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Smarter waste strategies: Helping deliver on the promise of advanced nuclear
At COP28, held in Dubai in 2023, a clear consensus emerged: Nuclear energy must be a cornerstone of the global clean energy transition. With electricity demand projected to soar as we decarbonize not just power but also industry, transport, and heat, the case for new nuclear is compelling. More than 20 countries committed to tripling global nuclear capacity by 2050. In the United States alone, the Department of Energy forecasts that the country’s current nuclear capacity could more than triple, adding 200 GW of new nuclear to the existing 95 GW by mid-century.
C. D. Andriesse, R. H. J. Tanke
Nuclear Technology | Volume 65 | Number 3 | June 1984 | Pages 415-421
Technical Paper | Nuclear Safety | doi.org/10.13182/NT84-A33397
Articles are hosted by Taylor and Francis Online.
Existing data on the release of fission products (FPs) from UO2 above 1000°C show that the dominant transport process consists of elementary diffusion within grains. For many FPs, the noble gases among them forming an exception, this diffusion is characterized by an activation energy of ∼2.6 eV, which is close to the one for oxygen and very different from the one for uranium. Assuming that oxygen diffusion represents the diffusion of FPs, it can be predicted that diffusion is enhanced when there is excess oxygen in the lattice. An empirical relation between the pertinent activation energy and the overstoichiometry induced by uranium fission (burnup) is given. The transport by diffusion has to be driven by some gradient, and it is argued that the temperature gradient dominates over the concentration gradient. This argument leads to a complete description of the release rate in terms of the grain size, the central and surface temperatures, and the heat of transport. The heat of transport plays a crucial role as it varies greatly for the various FPs. Existing data allow estimation of values ranging from 0.1 eV for refractory products to more than 100 eV for volatile products. These variations appear to be correlated with variations in the bond strengths between FPs and oxygen, being the more reactive element in UO2. An empirical model of the dependence of the heat of transport on this bond strength is given, so that release rates for all the FPs can be derived from chemical tables. Finally, consistency of the measured release data with other independently obtained fuel parameters is proven.
