UT scientists patent technology to cope with heat buildup in nuclear fusion

A team of University of Texas physicists has patented a technology that could solve a major drawback of nuclear power — radioactive waste. The innovation, which will not be tested for at least a couple more years, could lead to…

A team of University of Texas physicists has patented a technology that could solve a major drawback of nuclear power — radioactive waste.

The innovation, which will not be tested for at least a couple more years, could lead to the efficient incineration of such waste and a safer way to generate nuclear-powered electricity.

The problem of radioactive waste, along with safety anxieties among the public, has long vexed the nuclear industry. The United States has wavered on whether to set up a long-term repository for long-lasting waste in remote spots such as Yucca Mountain, Nev.

The UT scientists received a patent in August for technology that allows the pairing of nuclear fusion and fission to incinerate nuclear waste. Fusion produces energy by fusing atomic nuclei, and fission produces energy by splitting atomic nuclei.

“One washes the hands of the other,” professor Swadesh Mahajan said.

Neutrons, which Mahajan calls “beasties” because of their destructive inclinations, from the fusion process could be used to destroy radioactive waste from the fission process associated with the generation of electricity.

“It can remove fission’s sins,” he said.

The scientists’ innovation addresses a prosaic but crucial barrier to making the nuclear fusion process physically more compact and, thus, capable of being paired with the fission reactors. That barrier is enormous heat.

Called a Super X Divertor, the innovation is the sort of heat exhaust system only a nuclear physicist could dream up: It reconfigures electromagnetic fields within a fusion reactor, allowing the reactor to handle much hotter temperatures in more compact spaces.

That innovation can allow fusion reactors to be built much smaller and allow them to be coupled with a traditional fission reactor for on-site incineration of radioactive waste.

“We call it the tail wagging the dog,” UT senior research scientist Prashant Valanju said of the innovation.

The UT research is funded by the U.S. Department of Energy. A laboratory in the United Kingdom will add the Super X Divertor technology to a small fusion machine it is modifying. Experiments could begin by 2015.

The byproducts of the incineration of radioactive waste should be far less radioactive, with a half-life of only several decades, compared with the half life of at least 10,000 years of reactor waste that has not been incinerated, said UT senior research scientist Mike Kotschenreuther.

Mahajan said less toxic waste would be a boon in the U.S. and elsewhere.

“We couldn’t get one … Yucca Mountain,” Mahajan said. “What about India, with a population so large that it has little uninhabitated space? And even if we could get a Yucca, you (would) have a potential plutonium mine that would last thousands of years.”

The innovation has broader consequences beyond the destruction of waste, Kotschenreuther said. In the long-term, reactors, made safer, smaller and cheaper to build by dint of the divertor, could help displace fossil fuel plants that contribute to global warming.

Since the scientists began their work, an earthquake and tsunami struck Japan, leading to a cascade of failures at the Fukushima nuclear facility and a general chill on the nuclear industry.

The Fukushima disaster “makes disposal of waste more relevant, but it makes the public more reticent about nuclear power,” Kotschenreuther said.

He and the other scientists said nuclear power is overall many times safer than coal plants, which have generated pollution that has been linked to thousands of deaths annually.