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Part 1 of 2 Parts
The Hanford Nuclear reservation in Benton County, Washington is said to be one of the most radioactively contaminated installations in the World. The U.S. used the site to create weapons grade plutonium for the U.S. military. There are fifty-five million gallons of radioactive waste on the site. Currently there is an estimated timeline reaching into the 2080s for cleaning up the site.
There is a complex assembly including several state and federal agencies, private contractors, tens of thousands of workers, local residents, and advocates who are all invested in a colossal effort to clean up Hanford. It is estimated to be the largest nuclear cleanup project in the world.
The Hanford site is at a pivotal moment. It is set to finally transform the nuclear leftovers of a century past into glass that can be safely stored. This process is called vitrification. Last October, the first of two melters used to vitrify the waste were put into operation. The second melter is scheduled to launch this spring.
Nikolas Peterson is the executive director of Hanford Challenge, a nonprofit watchdog. He said, “They’re doing something out there that has never been done before. I think I have to constantly remind myself of that even when I’m critical of the facility.”
For staff at the Pacific Northwest National Laboratory (PNNL), who are developing and testing the glass formulations for immobilizing radioactive waste, this moment in time feels significant.
Tom Brouns is the lead of the environmental manager sector at PNNL. He has worked at Hanford for more than 30 years. He said, “It’s really exciting to see how far it’s come. It’s taking a long time but it’s so close.”
Vitrification is not a novel technology. The same process is used in making pottery. High heat is applied to a material that leads to metamorphosis of the original substance.
Researchers in France have studied the vitrification of nuclear waste since the 1950s. The country successfully built several facilities to tackle the cleanup of radioactive waste. Within this specialized industry, it’s considered one of the best methods to stabilize radioactive waste. It is expensive but it performs well over hundreds or thousands of years. Vitrification is an international standard when it comes to managing waste with high levels of radioactivity.
The process being developed to vitrify radioactive waste at Hanford is highly complex and involves multiple steps.
The process begins with a removal system that separates high-level waste that’s more toxic and radioactive from low-activity waste that is simpler to process and store. Separating the waste is critical to better management, treatment and disposal.
According to a 2023 report from the U.S. Government Accountability Office (GAO), about 95% of the waste in storage tanks is low-level waste when it comes to the physical volume. High-level waste only compromises about 5% of the volume but includes more than 70% of the radioactivity.
The low-level waste is pumped to a separate holding tank and is then pumped into another tank for mixing. Silica along with other additives are added to create the material that will ultimately be glass.
That mixture is pumped into melters which are giant three-hundred-ton devices that are the “heart” of the vitrification process. These generate heat at 2,100 degrees Fahrenheit and will create a molten substance over several days. This molten material is poured into stainless steel canisters where it eventually cools enough to become solid glass.
Brouns explained that “Glass is a superior matrix because the radio nuclei actually get trapped in the chemical matrix of the glass.”
Please read Part 2 next