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Isotopes & Radiation
Members are devoted to applying nuclear science and engineering technologies involving isotopes, radiation applications, and associated equipment in scientific research, development, and industrial processes. Their interests lie primarily in education, industrial uses, biology, medicine, and health physics. Division committees include Analytical Applications of Isotopes and Radiation, Biology and Medicine, Radiation Applications, Radiation Sources and Detection, and Thermal Power Sources.
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2024 ANS Annual Conference
June 16–19, 2024
Las Vegas, NV|Mandalay Bay Resort and Casino
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
College students help develop waste-measuring device at Hanford
A partnership between Washington River Protection Solutions (WRPS) and Washington State University has resulted in the development of a device to measure radioactive and chemical tank waste at the Hanford Site. WRPS is the contractor at Hanford for the Department of Energy’s Office of Environmental Management.
Naphtali M. Mokgalapa, Tushar K. Ghosh, Sudarshan K. Loyalka
Nuclear Technology | Volume 186 | Number 1 | April 2014 | Pages 45-59
Technical Paper | Reactor Safety | doi.org/10.13182/NT13-9
Articles are hosted by Taylor and Francis Online.
In high-temperature gas reactors, graphite particle adhesion and resuspension from structural surfaces play a role in source term estimations. This paper describes measurements of the adhesion force between an irregular graphite cluster (henceforth called a graphite particle) and Hastelloy X samples having different surface conditions. An atomic force microscope (AFM) was used. The graphite particle was attached to the AFM probe and then brought directly into and out of contact with the surface in air; the adhesion force was obtained from the resultant force curve. The adhesion forces of the graphite particle with Hastelloy X (as received, polished, and different oxidations) and mica surfaces were determined. From the resulting adhesion forces, the work of adhesion W12 (energy per unit area) was calculated. Although the values of the measured pull-off (adhesion) forces were found to be of the same order of magnitude, they differed by surface condition depending where on the sample the adhesion force was measured. The theoretical value of the adhesion force was calculated using the theory of Johnson, Kendall, and Roberts. When compared to the values calcluated from this theory, the measured values were lower by a factor of 100 in some cases and 1000 in others. This difference may be due to the approximation of the irregular graphite cluster probe as a perfect graphite particle sphere and to not taking into consideration asperities on the surface of the particle probe. Additionally, covalent bonds may form between the surface elements and the graphite particle because of the applied load. In this paper, the effects of oxidation on the adhesion of graphite particles to the mica and Hastelloy X surfaces are also discussed.