COLLEGE STATION, April 30, 2013 — In the mind of Texas A&M University physicist Peter McIntyre, two of America's most pressing energy challenges -- what to do with radiotoxic spent nuclear fuel and dwindling energy resources -- can be solved in one scientific swipe.
He is developing the technology that is capable of destroying the dangerous waste and, at the same time, potentially providing safe nuclear power for thousands of years into the future.
In his high-energy physics laboratory east of the Texas A&M campus, McIntyre and his research team are developing a new form of green nuclear power that would extract 10 times more energy out of spent nuclear fuel rods than currently obtained in the first use, as well as destroy the transuranics -- the chemical elements beyond uranium in the periodic table -- lurking within the hazardous toxic soup of used nuclear fuel.
Buoyed by seed funding from Texas A&M University ($750,000) and the Cynthia and George Mitchell Foundation ($500,000), McIntyre is preparing a proposal to the U.S. Department of Energy seeking the large-scale funding that would enable him to take the next steps.
Although viewed as a major national issue, McIntyre says the nuclear waste problem is a multifaceted one for which no viable solution yet has emerged, despite decades of discussion. Most recently in 2010, federal authorities scrapped a plan to create a nuclear waste dump at Yucca Mountain in Nevada to store the nationwide spent nuclear fuel capacity that now stands at 65,000 tons.
“In my opinion, the only way to properly deal with transuranics is to destroy them,” McIntyre said. “They are an unthinkable hazard if they ever get into the biosphere. There has long been discussion that we could find a site like Yucca Mountain that’s so isolated from groundwater and so stable geologically that we could say with confidence it will be the same 100,000 years from now as it is today, and that burying fuel there, closing the door and forgetting it is something we can responsibly do. I don’t buy those arguments.”
Each of the nation’s 104 reactors is fueled with about 90 tons of enriched uranium fuel, packaged in sealed metal tubes called fuel pins. As the uranium fissions, the byproducts are trapped inside these pins, where they accumulate and begin to take on neutrons that would otherwise be driving the continuing fission process. The ongoing build-up, which includes the heavier transuranic elements, renders the reactor non-operational after about five years once the fission process stops. At this point, the pins are replaced with a new set, and the spent fuel typically is stored in a pool of water at the reactor site.
McIntyre, a professor since 1980 in the Department of Physics and Astronomy and the inaugural holder of the Mitchell-Heep Chair in Experimental High-Energy Physics within the George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, describes his team’s technology as a “win-win.”
“It destroys the bad stuff — the transuranics — and recovers the good stuff — the fuel,” he said.
To destroy the transuranics, McIntyre’s team has developed a conceptual design for accelerator-driven subcritical fission in a molten salt core (ADSMS). With this technology, the transuranics are extracted into molten salt using a process called pyroprocessing, in which the spent fuel pins are chopped up and loaded into a basket, which is placed in a pot of molten salt. The oxide fuel inside the pins dissolves in the molten salt so that all of the remaining fuel — along with all of the transuranics — is extracted into the molten salt. The transuranics could then be destroyed through subcritical nuclear fission, which is driven by a beam of energetic protons within the custom-built, high-efficiency accelerator he envisions.
McIntyre’s design builds on work at Argonne National Laboratory and Idaho National Laboratory as well as the PRIDE facility in South Korea which demonstrated the process for extracting the fuel and separating the transuranic elements and fission products in molten salt. Scientists from those teams are collaborating with McIntyre in the new development.