The last group contains transuranic elements such as neptunium and plutonium. The pure plutonium produced in other processes is relatively easy to handle–it produces little heat and little dangerous radiation. It’s also hard to detect, because it doesn’t emit many neutrons. These qualities make it a dangerous security risk. But the system that GE Hitachi has designed, which sorts materials by applying a voltage to a molten salt, doesn’t separate plutonium from the other transuranic elements. Combined with these other elements, the fuel would release 1,000 times more heat and 10,000 times more gamma rays, so it would be much more difficult to steal, Loewen says.
Indeed, the combination of transuranic elements would likely eventually kill anyone who attempted to take it, he says. Although this wouldn’t stop terrorists willing to die to get it, the material also releases 1,000 times more neutrons than pure plutonium, making it far easier to detect.
Charles Forsberg, executive director of the MIT Nuclear Fuel Cycle Project, agrees that these materials would likely be more difficult to steal than plutonium, but he notes that the processing technology could be dangerous in the hands of a nation wanting to repurpose the materials for weapons rather than power plants.
The plutonium and other elements separated from nuclear waste in the GE Hitachi process can be used in a type of nuclear power plant that has been used in Japan, and that is being built in a few other countries, that uses molten sodium as the coolant, instead of the water used in U.S. nuclear power plants. Sodium-cooled reactors allow neutrons emitted during fission to maintain the high energy levels required to use this fuel. The particular type of reactor GE Hitachi has designed–called PRISM–would be compatible with the mix of elements produced by its separation technology. The technology has not yet been approved for use in the United States. One reason is that sodium metal is highly reactive and requires special safety precautions.
Although it could reduce nuclear waste and provide a valuable fuel source for nuclear power plants, the GE Hitachi technology would not completely eliminate the need for long-term storage, Forsberg says, because perfect separation of the components of nuclear waste isn’t possible–there will always be some fraction of the material that needs to be stored for more than 10,000 years.