With the end of the Cold War, the superpowers left a large amount of low-level radioactive waste. However, the team of scientists of the U.S. Department of Energy’s Northwest Pacific National Laboratory has already proved that they will become cleaner in the future. It is reported that PNNL has for the first time been a low-emitting nuclear The waste was continuously vitrified. In the lab, the research team had solidified three gallons (11.4 L) of waste from Hanford Site, Washington. The researchers fixed radioactive chemicals inside and changed the waste. Become a more durable glass.
PNNL scientists fuse radioactive waste into the glass of a test platform designed specifically to mimic the 'DirectFeedLow-ActivityWaste' system built at Hanford.
Nuclear waste is a major environmental issue facing humankind:
Even if every nuclear reactor on earth is suddenly shut down and no longer new, we still need to process millions of gallons of waste produced in 3/4 centuries, not to mention in future research reactors and hospital radiation laboratories. Wasted.
The core of the problem is to find a place for long-term storage of nuclear waste, or to develop a chemically inert process that makes it impossible to interact with the environment.
Among current nuclear waste disposal programs, the more promising one is 'vitrification' - that is to say, the filtered waste is mixed with the glass forming material and then heated in the furnace to produce borosilicate glass - the latter Can maintain stability for thousands of years!
This method is usually used on high levels of nuclear waste (such as spent fuel rods), but the reality is that there are hundreds of times lower levels of nuclear waste waiting to be processed:
This includes wastes that have been contaminated with radioactive elements, or that have been exposed to neutron radiation, such as declining medical isotopes, clothing that has been poisoned, dead carcasses of experimental animals, and a large number of low-reactor reactor residues in the form of industry.
The red material is radioactive waste from one of Hanford's underground storage tanks. This is the first time that it was made into a solidified glass in a continuous process, similar to the one that will be put into use in the future.
The good news is that PNNL has collaborated with the U.S. Department of the Environment River Conservation Office (ORP) and the Washington River Protection Solutions (WRPS) organization that manage the Hanford nuclear waste storage tank.
PNNL will pilot a new process for 'direct shooting of low-level radioactive waste', which is expected to vitrify the millions of gallons of low-level radioactive waste left behind by the United States during the nuclear arms race on a certain day in the future.
The test aims to demonstrate that nuclear waste can be processed continuously (rather than in batches), to better understand how this method works, and to be ready to expand its scale.
During the demonstration, PNNL used liquid nuclear waste from Hanford, and used filters and ion exchange columns to clarify the solid and heavy metal helium.
The processed liquid is mixed with the raw materials used to make the glass, which is then pumped into a 5 inch (12.7 CM) wide smelting furnace and heated at a controlled rate to 2100°F (1149°C).
About every 30 minutes or so, about 8 ounces (227 grams) of glass is extruded to a total weight of 20 pounds (9.1 kilograms).
At the same time, the radioactive gases released by the vitrification process are condensed and reduced to liquids. They will be concentrated and used for subsequent vitrification.
Finally, PNNL will analyze the glass and grouting to determine if they meet the processing criteria.
The agency said that they plan to launch another laboratory vitrification test later this year. During this period, a different filtration and particle exchange process will be validated. Another batch of liquid from the Hanford waste pool will be processed and then made into glass. .
