American scientists are announcing this week that they've got plans to release new unmanned aircraft with capabilities for months of flight without refueling. These new drones would be nuclear-powered and will be developed by Sandia National Laboratories - this being the US government's principal research and development agency. They're also working with defense contractor Northrop Grumman, who are the ones who specifically noted that these drones will have an increased flying time over previous models "from days to months", this including more power for operating equipment as well.
The team of Sandia-Northrop Grumman are working with patented drone technology that works with a helium-cooled nuclear reactor. This patent comes from all the way back in 1986, while similar nuclear-powered aircraft patents are known to have been filed as early as the 1950s. The team notes that these kinds of nuclear drones have been able to bring both longer surveillance time and enough power to do more research whilst in flight than ever before as well.
This project has inspected and tested power systems ranging from large to medium sized drones and has, it appears, settled on a nuclear solution at this time. Though reports show that the project is now "completed" in some aspects, it appears that there may be no real future for an actual, working drone for the time being. Sandia reports:
"Sandia is often asked to look at a wide range of solutions to the toughest technical challenges. The research on this topic was highly theoretical and very conceptual. The work only resulted in a preliminary feasibility study and no hardware was ever built or tested. The project has ended." - Sandia
Concerns for the project mostly came from a crashed vehicle, as if it were to fall into enemy hands or fall into a civilian area, complications could arise. Thus is also the problem with any and all drones flown for military purposes, but in this case the danger of the plane effectively becoming a "dirty bomb" appear to have been too great.