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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.
Paul E. Mariner (SNL)
Proceedings | 16th International High-Level Radioactive Waste Management Conference (IHLRWM 2017) | Charlotte, NC, April 9-13, 2017 | Pages 286-293
Humic complexation has the potential to increase actinide mobility and hamper waste isolation in geologic nuclear waste repositories. This study shows that humic complexation of tetravalent actinides (Th(IV), U(IV), Np(IV), and Pu(IV)) has been overestimated in past performance assessments of the Waste Isolation Pilot Plant (WIPP). Major reductions are needed for PHUMSIM and PHUMCIM, the equilibrium concentration ratios of humic-bound aqueous actinide to non-colloidal aqueous actinide. These coefficients are currently set at a value of 6.3 based on Th(IV) measurements in particle size fractions of seawater. Actual humic partitioning is expected to be significantly lower in WIPP brines primarily because pH is higher (~9) and concentrations of competing cations (e.g., Mg2+) are higher. In this work, data from recent studies of Th(IV)-humic, U(IV)-humic, and Ca2+-humic complexation are used to simulate competitive humic complexation under WIPP repository conditions and to estimate new An(IV) PHUMSIM and PHUMCIM values. The new lower coefficients reduce the humic-bound An(IV) concentrations by more than 99%, causing a reduction in total mobile An(IV) concentrations by 85% to 86%, assuming no other type of An(IV) colloid (i.e., intrinsic, microbial, and mineral fragment colloids) is present in significant concentrations.