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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.
Tomio Okawa, Akio Kotani, Naoya Shimada, Isao Kataoka
Nuclear Technology | Volume 158 | Number 2 | May 2007 | Pages 304-313
Technical Paper | Nuclear Reactor Thermal Hydraulics | doi.org/10.13182/NT07-A3844
Articles are hosted by Taylor and Francis Online.
The critical heat flux in an annular two-phase flow regime is influenced significantly by an obstacle placed in a flow channel. Since the transition to critical heat flux condition in this flow regime is caused by the depletion of liquid film, it is probable that the flow obstacle has a notable influence on the rate of droplet deposition and, consequently, the film flow rate in the annular regime. Also, the obstacle's effect on the deposition rate would be important in predicting the critical heat flux in a boiling water reactor core because the grid spacer can be regarded as a flow obstacle placed in the subchannel. The obstacle effect was studied experimentally for vertical upward air-water annular flow; placing 12 small tubes of different cross sections concentrically in the test section tube one by one, the influence of obstacle geometry on the deposition rate was investigated. The rate of droplet deposition markedly increased if the present tubular obstacle was placed; the rate of increase was between ~30 and 200% and depended primarily on the obstacle shape. Using the experimental data, an empirical correlation to account for the obstacle's effect was proposed.