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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.
Guangliang Chen, Zhijian Zhang, Zhaofei Tian, Thompson Appah, Lei Li, Xiaomeng Dong, Peizheng Hu
Nuclear Science and Engineering | Volume 188 | Number 3 | December 2017 | Pages 270-281
Technical Paper | doi.org/10.1080/00295639.2017.1367568
Articles are hosted by Taylor and Francis Online.
In a subchannel analysis, the assumptions of the physical models may be invalid when three-dimensional (3-D) effects play an important role because a large-scale model cannot consider a small-scale physical process. However, in a pressurized water reactor (PWR), the flow process has a high 3-D effect due to the effect of complex structures, such as dimple, spring, and mixing vane. A computational fluid dynamics (CFD) analysis can give more detailed physical information. So, the modeling assumptions of the subchannel analysis codes were analyzed using data from CFD analysis, and some issues were found: The spatial acceleration of the cross-flow rate and the viscous force from fluid to fluid should not be neglected; the lateral pressure gradient not only is a driving force but also can be a resistance at some vertical range; the traditional “resistant force term” has the same direction with the cross flow at some vertical ranges. To improve the subchannel code, one physical term considering both the driving and the resistance effect is suggested to be added in the traditional transverse momentum equation. The solution for this new term and the method using spatial acceleration of the cross flow were also provided.