Radioactive Waste 198 - New Process Can Immobilize Iodine-129 in Glass Logs At Room Temperature
One of the biggest problems with nuclear power generation and nuclear weapons development is the radioactive waste that is created. Some of these waste materials can be dangerous for millions of years. There have been a variety of suggested approaches for locking such waste away. One system of waste disposal that the U.S. has been trying to develop is a deep geological repository so the waste can be buried underground. Even tucked away underground in a mine, there is a danger that ground water could penetrate the repository and leach out the radioactive materials if they are stored in barrels. It is even possible that leached materials could collect and start a nuclear chain reaction.
The process of vitrification was developed to help prevent this. In vitrification, radioactive waste is combined with a mixture of materials including sand. Then the mixture is heated until it melts and fuses into a glass log which is then stored in the repository. Making glass logs with the waste can immobilize it for tens of thousands of years at the least.
The scientists at the Hanford Nuclear Reservation have spent millions of dollars on a vitrification plant. Unfortunately, the waste they are trying to treat is highly varied with respect to chemical composition, granularity and viscosity. It turns out that the varied composition of the waste stream being fed into the vitrification plant was generating turbulence that could rupture piping, releasing explosive hydrogen gas. They had to stop work on the plant so they could modify the design. They are still working on completing the vitrification plant at Hanford.
Ashutosh Goel at Rutgers has been researching vitrification for decades. He is an Assistant Professor of Materials Science and Engineering. His latest project is the invention of a new method that can immobilized radioactive iodine in a ceramic material at room temperature. Radioactive Iodine-129 is very dangerous to human health. If it is released into the environment, it will disperse quickly in air and water and can stay around for millions of years. Iodine-129 accumulates in the human thyroid gland and increases the chances of developing cancer. Goel is also working on six other glass related project with funding totaling over six million dollars.
The U.S. Department of Energy provided much of Goel's funding. They are charged with cleaning up the waste from decades of nuclear weapons research carried out at sixteen major facilities located in remote areas of Idaho, Nevada, South Carolina, Tennessee and Washington state. The Hanford Nuclear Reservation in Washington is one of DoE's most difficult clean up jobs. Other institutions that Goel is working with include the National Science Foundation, Corning Inc., Washington State University, University of North Texas and the Pacific Northwest National Laboratory.
One of Goel's major breakthroughs involves mass producing chemically stable apatite minerals also known as glasses, to immobilize iodine-129 without needing the high temperatures that other such processes require. He is also working with biosilicate glasses that don't crystallize for the purpose of immobilizing sodium and alumina in high-level nuclear waste. Eventually, the work of Goel could possibly useful in the treatment and disposal of spent nuclear fuel which is piling up at cooling pools at reactors all over the U.S.
Ashutosh Goel:
