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Division Spotlight
Thermal Hydraulics
The division provides a forum for focused technical dialogue on thermal hydraulic technology in the nuclear industry. Specifically, this will include heat transfer and fluid mechanics involved in the utilization of nuclear energy. It is intended to attract the highest quality of theoretical and experimental work to ANS, including research on basic phenomena and application to nuclear system design.
Meeting Spotlight
International Conference on Mathematics and Computational Methods Applied to Nuclear Science and Engineering (M&C 2025)
April 27–30, 2025
Denver, CO|The Westin Denver Downtown
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
Argonne’s METL gears up to test more sodium fast reactor components
Argonne National Laboratory has successfully swapped out an aging cold trap in the sodium test loop called METL (Mechanisms Engineering Test Loop), the Department of Energy announced April 23. The upgrade is the first of its kind in the United States in more than 30 years, according to the DOE, and will help test components and operations for the sodium-cooled fast reactors being developed now.
Guangchun Zhang, Albert Hsieh, Won Sik Yang, Yeon Sang Jung
Nuclear Science and Engineering | Volume 193 | Number 8 | August 2019 | Pages 828-853
Technical Paper | doi.org/10.1080/00295639.2018.1560854
Articles are hosted by Taylor and Francis Online.
This paper presents the new acceleration schemes implemented in the three-dimensional (3-D) transport solver PROTEUS-MOC in conjunction with the fixed-point iteration (FPI) methods based on a single generalized minimal residual (GMRES) iteration and one or two transport sweeps per group in each outer iteration. In order to adopt a FPI scheme that employs only one or two inner iterations, single- and two-level consistent partial current–based coarse-mesh finite difference (pCMFD) acceleration methods were implemented to remove the instability problem of the consistent coarse-mesh finite difference (CMFD) method encountered when the inner iteration convergence is not sufficiently tight. In the spatial two-level acceleration method to speed up the lower-order diffusion calculations, the first level solves a fine-mesh finite difference fixed-source problem and the second level solves a CMFD eigenvalue problem. The implemented acceleration schemes were tested using the C5G7 benchmark problems, a critical core configuration of the Transient Reactor Test Facility (TREAT), and a C5G7 transient benchmark problem. Numerical test results showed that the consistent pCMFD acceleration is always stable even for the FPI methods with one inner iteration and that the single transport sweep method is always more efficient than the single GMRES iteration method. It was also observed that the two-level pCMFD acceleration in conjunction with the FPI with single transport sweep per outer iteration is very effective in reducing the number of outer iterations and the lower-order diffusion calculation time. Compared to the current iteration scheme of PROTEUS-MOC with fully converged GMRES iteration without acceleration, this acceleration reduced the total computational time by factors of 33.7, 19.9, and 26.0 for the two-dimensional C5G7, 3-D C5G7, and TREAT M8CAL criticality problems, respectively. The gain was even much larger for transient fixed-source problems (TFSPs) that are near critical. The speedup factor was 100 for one TFSP with subcriticality level of 40 mk and 519 for another TFSP with subcriticality level of 9 mk.
