Mike Kotschenreuther

University of Texas researchers have patented the concept for a hybrid nuclear reactor that may reduce nuclear waste by combining fission and fusion, processes that produce nuclear energy by splitting and fusing parts of the atom.

Researchers Swadesh Mahajan, Prashant Valanju, and Mike Kotschenreuther of the College of Natural Sciences Institute for Fusion Studies have received a patent for the tokamak device. Nuclear power does not produce greenhouse gases, but it does produce radioactive waste. This device will use magnetic fields to produce fusion reactions and burn nuclear waste from the fission process. This will generate additional energy, reducing the amount of waste.

Mahajan, a physics and fusion research professor, said in order for nuclear energy to become useful, the waste must be destroyed. Currently nuclear reactors produce energy through nuclear fission, which creates short-term and long-term radioactive waste. He said short-term radioactivity has a lifespan of about 20 to 30 years, but long-term radioactivity causes the major environmental concerns.

“Fusion is still a research project,” Mahajan said. ”Its promise is wonderful, because one will be able to produce large amounts of energy for large amounts of time and will not leave too much environmentally damaging residue.”

Mahajan said they were the first to come up with this technology because they were able to devise a system in which the fusion reaction could take place in a compact machine.

In order for it to be compact, the researchers had to develop several technologies. Mahajan said a crucial invention was the Super X Divertor, which diverts the heat produced by the fusion reaction. This made it possible to produce and sustain large numbers of neutrons in a small volume.

Valanju, who also worked on the project, said nuclear fusion generates neutrons that will destroy the nuclei of the waste.
Nuclear power does not emit greenhouse gases, but there are questions about nuclear safety, senior researcher Kotschenreuther said.

“If you replace every coal fire and gas power plant with a nuclear power plant, you not only eliminate the greenhouse gases, you eliminate the number of people, civilians. These are not coal miners, civilians, you and I, killed from the various forms of pollution produced from the other plants,” Kotschenreuther said.

The researchers all agreed the fundamental drive for their research was to find a solution to the nuclear waste produced by nuclear power plants so the technology could be safe.

“I do not ever object to people having high standards from nuclear energy,” Mahajan said. “That is the right thing to do.”

Printed on Friday, September 14, 2012 as: UT researchers patent concept to reduce waste