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2025 ANS Winter Conference & Expo
November 9–12, 2025
Washington, DC|Washington Hilton
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The journey of the U.S. fuel cycle
Craig Piercycpiercy@ans.org
While most big journeys begin with a clear objective, they rarely start with an exact knowledge of the route. When commissioning the Lewis and Clark expedition in 1803, President Thomas Jefferson didn’t provide specific “turn right at the big mountain” directions to the Corps of Discovery. He gave goal-oriented instructions: explore the Missouri River, find its source, search for a transcontinental water route to the Pacific, and build scientific and cultural knowledge along the way.
Jefferson left it up to Lewis and Clark to turn his broad, geopolitically motivated guidance into gritty reality.
Similarly, U.S. nuclear policy has begun a journey toward closing the U.S. nuclear fuel cycle. There is a clear signal of support for recycling from the Trump administration, along with growing bipartisan excitement in Congress. Yet the precise path remains unclear.
Seok-Ki Choi, Myung-Hwan Wi, Won-Dae Jeon, Seong-O Kim
Nuclear Technology | Volume 152 | Number 2 | November 2005 | Pages 223-238
Technical Paper | Nuclear Reactor Thermal Hydraulics | doi.org/10.13182/NT05-A3672
Articles are hosted by Taylor and Francis Online.
A computational study of thermal striping in an upper plenum of the Korea Advanced Liquid-Metal Reactor (KALIMER) was performed. The primary objective of the present study was to find the distribution of the amplitude of temperature fluctuation in the hot pool of KALIMER. The computations were performed using the CFX-4 code with the differential stress and flux turbulence model and the Van Leer convection scheme. Two cases with different outlet velocity of the control rod fuel assemblies are considered. The distributions of the velocity vector, temperature, and temperature fluctuation were obtained from the calculation. In order to quantitatively understand the amplitude of temperature fluctuation at the bottom wall of the upper internal structure (UIS), the amplitude of the fluctuation of temperature in the radial and angular directions was investigated. The amplitude of temperature fluctuation at the UIS bottom plate was largely dependent on the magnitude of the outlet velocity of the control rod fuel assemblies. From the calculated results, it was found that the largest temperature fluctuation occurred at the radial edge of the UIS bottom in the KALIMER design. Since thermal striping is dependent on the amplitude of temperature fluctuations and frequency, the region of the UIS bottom edge needs to be analyzed with a detailed unsteady calculation.
