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2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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Researchers use one-of-a-kind expertise and capabilities to test fuels of tomorrow
At the Idaho National Laboratory Hot Fuel Examination Facility, containment box operator Jake Maupin moves a manipulator arm into position around a pencil-thin nuclear fuel rod. He is preparing for a procedure that he and his colleagues have practiced repeatedly in anticipation of this moment in the hot cell.
Jin-Seok Hwang, Jong-Won Kim, Heon-Uk Nam, Goon-Cherl Park
Nuclear Technology | Volume 176 | Number 2 | November 2011 | Pages 260-273
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT11-A13300
Articles are hosted by Taylor and Francis Online.
A major safety factor in marine reactor design, critical heat flux (CHF), is assessed using the MARS system analysis code under heaving conditions. As gravity acceleration changes, the CHF is affected by the thermal hydraulics in the reactor through inlet flow fluctuations. Performing the analysis with the MARS code, which uses the properties of water for the working fluid, requires applying the CHF experimental data using fluid-to-fluid (FTF) scaling because most CHF experiments are conducted with Freon (R-113) as the working fluid. The FTF scaling methods suggested by Ahmad, Katto, and Coffield are adopted and compared. Otsuji et al.'s experiment, which was conducted using mass flow rate oscillation, is applied to evaluate the capability of MARS for heaving conditions. According to the calculations the FTF methods of Ahmad, Katto, and Coffield show good agreement (within an error of ±10.73% for Otsuji et al.'s experiment) for inlet flow rate oscillation corresponding to gravity acceleration in a vertical direction. In addition, variation of the acceleration affects the flow conditions, such as the mass flow rate and the void fraction. Thus, MARS has a noteworthy ability to predict the CHF for heaving conditions by simulating inlet flow rate oscillation.