World’s largest nuclear waste site to use new safer storage method

Posted on 8 Mar 2017 by Aiden Burgess, Tim Brown

A Rutgers University researcher has developed a new method which could help store radioactive nuclear waste for millions of years by turning it into glass.

Rutgers researcher, Professor Ashutosh Goel, has discovered a way to immobilize radioactive nuclear waste, material that is the result of decades of nuclear weapons production.

An assistant professor at Rutgers’ Department of Materials Science and Engineering, Professor Goel is the primary inventor of a new method to immobilize radioactive iodine-129 in ceramics at room temperature.

This ‘vitrification’ process involves melting the nuclear waste together with glass, forming compounds in a cylindrical container which also serves as its storage container.

Professor Goel’s new method is a crucial invention in the advancement of immobilizing iodine-129, which poses a significant threat in that if released into the environment as it can linger for millions of years.

Iodine-129 poses a number of problems in that it can disperse rapidly in air and water and has a half-life of 15.7 million years. Exposure to the compound can have a highly detrimental impact on the human thyroid gland and subsequently greatly increase the risk of cancer.

Professor Goel said it was imperative for radioactive waste such as iodine-129 to be immobilized and that glass was the perfect way to address this global problem.

“What we’re talking about here is highly complex, multi-component radioactive waste which contains almost everything in the periodic table,” he said. What we’re focusing on is underground and has to be immobilized. Glass is a perfect material for immobilizing the radioactive wastes with excellent chemical durability.”

Technique to be applied at Washington State nuclear waste site

The US Department of Energy (DOE) is one of Professor Goel’s major funders, and shapes to be the biggest beneficiary of the researcher’s discovery, which could revolutionize nuclear waste storage.

In southeastern Washington State, specialist nuclear engineering company, Bechtel National, is designing, constructing and commissioning the world’s largest radioactive waste treatment plant for the DOE. When complete, the Hanford Tank Waste Treatment and Immobilization Plant (WTP), also known as the Vit Plant, will process and stabilize 56 million gallons of radioactive and chemical waste currently stored at the Hanford Site.

The waste, a byproduct of national defense plutonium-production efforts during World War II and the Cold War era, resides in 177 aging underground tanks. Of these, more than one-third have already leaked, contaminating the subsurface and threatening the nearby Columbia River.

The plant will use the glass immobilization technique, which involves blending the waste with glass-forming materials and heating it to 2,100°F (1,149°C). This mixture is then poured into stainless steel canisters to cool and solidify. In this glass form, the waste is stable and impervious to the environment, and its radioactivity will safely dissipate over hundreds to thousands of years.

While this technique has been employed successfully at other radioactive waste clean-up sites, it has never been attempted at the scale of or on waste as complex as that stored at Hanford. The WTP Project is a feat of engineering and construction at an unprecedented level. It is the largest undertaking of its kind and one of DOE’s most technically challenging clean-up projects.

However, roll out of the technique may still be some years away with Professor Goel revealing that the new process for creating glass with radioactive waste is expected to start in 2022 or 2023. “The implications of our research will be much more visible by that time,” he said.

Nuclear power plants may also benefit from waste disposal method 

This method could also lead to ways to safely dispose of highly reactive spent nuclear fuel that is currently stored in commercial nuclear power plants.

Since finding a method to immobilise iodine-129, Professor Goel said he was hopeful of potentially finding a similar method for safely disposing spent nuclear fuel.

“It depends on its composition, how complex it is and what it contains,” he said. “If we know the chemical composition of the nuclear waste coming out of those plants, we can definitely work on it,”

In addition to his various roles at Rutgers University, Professor Goel is also the principal investigator (PI) or co-PI for six glass-related research projects receiving $6.34m in federal and private funding.