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Nuclear Energy Conference & Expo (NECX)
September 8–11, 2025
Atlanta, GA|Atlanta Marriott Marquis
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The RAIN scale: A good intention that falls short
Radiation protection specialists agree that clear communication of radiation risks remains a vexing challenge that cannot be solved solely by finding new ways to convey technical information.
Earlier this year, an article in Nuclear News described a new radiation risk communication tool, known as the Radiation Index, or, RAIN (“Let it RAIN: A new approach to radiation communication,” NN, Jan. 2025, p. 36). The authors of the article created the RAIN scale to improve radiation risk communication to the general public who are not well-versed in important aspects of radiation exposures, including radiation dose quantities, units, and values; associated health consequences; and the benefits derived from radiation exposures.
Zhengting Quan, Adam Dix, Ran Kong, Seungjin Kim, Mamoru Ishii, Mitchell T. Farmer
Nuclear Science and Engineering | Volume 197 | Number 5 | May 2023 | Pages 771-787
Technical Paper | doi.org/10.1080/00295639.2022.2082232
Articles are hosted by Taylor and Francis Online.
This work studies the hydrodynamics of the seven-pin wire-wrapped rod bundle in the sodium cartridge loop for the Versatile Test Reactor (VTR) through scaled water experiments and computational fluid dynamics (CFD) simulations. The scaling analysis is first performed to demonstrate the hydrodynamic similarity between water and sodium flows at the same Reynolds number . A separate-effects test facility is designed and constructed based on the scaling analysis. Detailed experimental data on the pressure drop covering a wide range of values (1165 to 27 689) are obtained, which are used to evaluate existing correlations for friction factor and to benchmark CFD simulations. The experimentally determined friction factors agree well with the Upgraded Cheng and Todreas Detailed Correlation and Pacio-Chen-Todreas Detailed Model within but are significantly underpredicted by Rehme’s correlation by 25%. Various CFD near-wall treatment methods are tested using ANSYS Fluent and evaluated by experimental data. It is found that when the recommended wall values are met, most of the near-wall treatment methods can give accurate friction factor predictions. The resolved near-wall method () with the Shear Stress Transport turbulence model and the scalable wall functions () with the realizable turbulence model can predict within . The standard wall functions () and nonequilibrium wall functions () with the realizable model can predict within ± 10%.