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Division Spotlight
Fusion Energy
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.
Meeting Spotlight
Utility Working Conference and Vendor Technology Expo (UWC 2024)
August 4–7, 2024
Marco Island, FL|JW Marriott Marco Island
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
The IAEA targets seafood contaminants and plastic pollution in oceans
Oceans link all the continents of the world, and fish don’t respect boundary lines. So it’s fitting that a global organization—the International Atomic Energy Agency—is helping nations detect and monitor both plastic pollution and biotoxins in marine algae that can lead to outbreaks of contaminated seafood.
T. V. Dury, M. T. Dhotre
Nuclear Science and Engineering | Volume 165 | Number 1 | May 2010 | Pages 101-116
Technical Paper | doi.org/10.13182/NSE08-90
Articles are hosted by Taylor and Francis Online.
Current designs of pressurized water reactors (PWRs) employ a boric acid solution in the primary cooling water to control core reactivity during operation and shutdown. However, situations could theoretically occur in which diluted borated water is present in the primary circuit. Scale experiments have been performed for a single-pump start-up, with subsequent computational fluid dynamics (CFD) simulation, to examine the accuracy with which the concentration distribution of diluted borated water entering a reactor core can be predicted. It was concluded that higher-order advection schemes must be used to obtain sufficient resolution of the velocity field and capture the larger-scale effects of the flow but that each turbulence model produces a different core-inlet boron concentration development and distribution. Though it was not the most sophisticated available, the two-equation RNG k- turbulence model produced the closest agreement with experiment. However, mesh independence of the computational results was not achieved. As a sequel to this scaled CFD study, a simulation was carried out of a full-size three-loop Siemens-type PWR featuring a perforated cylindrical flow baffle in the lower plenum. Results again showed different characteristics in time and space, depending on the turbulence model used. Comparative assessment of the results obtained with the code CFX-5 showed that correct geometrical modeling of a perforated flow baffle in the lower plenum is essential, as a porous medium representation of the baffle can lead to serious underprediction of mixing. This occurred particularly with the RNG model but also using more sophisticated turbulence models. Further refinement of the mesh is now necessary to achieve mesh independence of the results. This requires access to a massively parallel computer system.