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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.
T. N. Carlstrom
Fusion Science and Technology | Volume 48 | Number 2 | October 2005 | Pages 997-1010
Technical Paper | DIII-D Tokamak - Achieving Reactor Quality Plasma Confinement | doi.org/10.13182/FST05-A1055
Articles are hosted by Taylor and Francis Online.
DIII-D contributions to H-mode transition physics and power thresholds are reviewed. Two general approaches were pursued: (a) establishing scaling relations based on empirical observations and (b) acquiring a theoretical understanding of the physics of the transition. The interaction of experiment results and the development of theories over the early 1990s led to the highly successful and widely accepted model of shear suppression of turbulence by crossed electric and magnetic fields (E × B) as the cause of improved confinement in H-mode. Experimental studies have also examined parameters at the edge of the plasma in order to identify a control parameter for the transition and to test various theories of the transition. The effect of the direction of the [nabla]B drift on the H-mode power threshold is used as a tool to further understand the physics of the L-H transition. Results on DIII-D and other tokamaks have guided researchers to study turbulent generated flows as a possible trigger for the L-H transition. Access to H-mode is controlled by a power threshold, and it is important to predict the threshold for next-generation tokamaks. In addition to electron density and toroidal field dependencies, it is found that many other parameters affect the power threshold. Studies of plasma size, magnetic configuration, and neutral effects have been performed. DIII-D data have been used in an international tokamak database to help establish scaling relations to predict power thresholds in future devices.