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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.
Sang Won Lee, Han Gon Kim, Seung Jong Oh
Nuclear Technology | Volume 158 | Number 3 | June 2007 | Pages 396-407
Technical Paper | Thermal Hydraulics | doi.org/10.13182/NT07-A3850
Articles are hosted by Taylor and Francis Online.
APR1400 is an evolutionary pressurized water reactor developed in Korea. The emergency core cooling system (ECCS) of APR1400 has been improved by adopting an independent four-train safety injection system. Each train is composed of a safety injection pump and an accumulator with a fluidic device, the passive flow rate controlling equipment. Also, ECCS water is injected directly into the reactor vessel upper downcomer, ~2 m above the cold-leg centerline. With these design characteristics, more complex thermal-hydraulic phenomena can be observed in a large-break loss-of-coolant accident (LBLOCA) scenario. In this paper, the effects of these design characteristics on the LBLOCA scenario are examined using the RELAP5/MOD3.3 code. The code modeling capability in predicting the phenomena important to APR1400 ECCS design is examined using available experiments. It shows that RELAP5/MOD3.3 conservatively predicts the bypass rate and downcomer boiling phenomena. RELAP5/MOD3.3 code analysis of APR1400 LBLOCA with conservative assumptions show that ECCS design is adequate and there is no degradation of core cooling capability and reheat phenomena during the late reflood phase. All fuel rods are quenched in the early reflood phase when the fluidic devices are inactive, showing the effectiveness of the direct vessel injection and fluidic devices against an APR1400 LBLOCA scenario.