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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.
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Fusion Science and Technology
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Glass strategy: Hanford’s enhanced waste glass program
The mission of the Department of Energy’s Office of River Protection (ORP) is to complete the safe cleanup of waste resulting from decades of nuclear weapons development. One of the most technologically challenging responsibilities is the safe disposition of approximately 56 million gallons of radioactive waste historically stored in 177 tanks at the Hanford Site in Washington state.
ORP has a clear incentive to reduce the overall mission duration and cost. One pathway is to develop and deploy innovative technical solutions that can advance baseline flow sheets toward higher efficiency operations while reducing identified risks without compromising safety. Vitrification is the baseline process that will convert both high-level and low-level radioactive waste at Hanford into a stable glass waste form for long-term storage and disposal.
Although vitrification is a mature technology, there are key areas where technology can further reduce operational risks, advance baseline processes to maximize waste throughput, and provide the underpinning to enhance operational flexibility; all steps in reducing mission duration and cost.
K. C. Chen, R. C. Cook, H. Huang, S. A. Letts, A. Nikroo
Fusion Science and Technology | Volume 49 | Number 4 | May 2006 | Pages 750-756
Technical Paper | Target Fabrication | doi.org/10.13182/FST06-A1196
Articles are hosted by Taylor and Francis Online.
One of the current capsule designs for achieving ignition on the National Ignition Facility (NIF) is a 2 mm diameter graded Ge-doped CH shell that has a 160 m thick wall. The Ge doping is not uniform, but rather is in radial steps. This graded Ge-doped design allows rougher surface finish than the original undoped CH design, thus has a less stringent surface roughness requirement.We selected quality mandrels by coating dozens of mandrel batches to ~70 m thickness to amplify submicrometer defects on the mandrels and successively removed inferior batches. The Ge-doped CH layers are made by introducing (CH3)4Ge to the gas stream. The doping concentrations were determined by performing trial runs and were characterized by X-ray fluorescence and quantitative radiographic analyses, with good agreement between the methods demonstrated.The precise layer thickness and Ge concentrations were determined by a non-destructive quantitative contact radiograph. The as-deposited average layer thicknesses of the shells were 9.5 ± 1.1 m for inner undoped CH layer, followed by a 47.1 ± 0.5 m thick 0.83 ± 0.09 at. % Ge-doped CH, 10.0 ± 0.4 m thick 0.38 ± 0.04 at. % Gedoped CH and then 89.2 ± 0.5 m of undoped CH.The atomic force microscope derived power spectrum of the shell meets the new NIF standard. The shells had a root-mean-square surface roughness of ~ 24 nm (modes 100-1000). The few surface flaws are isolated domes ~1 m tall and 20 m in diameter.The PAMS mandrels were successfully removed by pyrolysis at 305°C for 10-20 h. After pyrolysis, the diameter and wall shrank 0.4% and 5.7%, respectively. Except for the outer undoped CH layer, which was 5.8 m less than the design specification, the average thicknesses of the three other layers met the NIF design specification after pyrolysis. The averages of the Ge doping concentrations were within the tolerance limits. The shell's inner surface has root-mean-square roughness of less than 6.5 nm.