They could supply energy to far-flung bases, power laser weapons and charge electric vehicles //

War zones are dangerous places. Where better, then, for a nuclear reactor? On March 9th America’s government awarded a trio of firms $39.7m to design “microreactors” that can supply a few megawatts of power to remote military bases, and be moved quickly by road, rail, sea and air.

The idea of small reactors is as old as nuclear power itself. In July 1951, five months before a reactor in Idaho became the first in the world to produce usable electricity through fission, America began building uss Nautilus, a nuclear-powered submarine. In the 1960s and 1970s small reactors powered bases in Alaska and Greenland, a radar facility in Wyoming, a research station in Antarctica and—from a cargo ship—the Panama Canal Zone. America still uses nuclear-powered submarines and aircraft-carriers. But land-based mini-reactors proved unreliable and expensive and have fallen out of favour