Nuclear transport

Figure 1 In NASA’s bimodal nuclear thermal rockets, fission reactions heat the liquid hydrogen propellant that steers the spacecraft, and could also be used to generate electrical power for the on-board instruments

In the mid twentieth century, the USA and the Soviet Union funded research aimed at developing nuclear-powered aircraft and ships capable of travelling for years without refuelling. The technology was developed for submarines, but aircraft presented a greater challenge because of the weight of the reactors and the shielding needed to protect the crew from radiation. In 1958 the Soviet Union claimed to have produced a nuclear plane but this was later found to be a hoax. Though neither country succeeded in making a nuclear aircraft, nuclearpowered rockets and spacecraft are now in use (Figure 1).

In 1945, Britain’s Minister of Fuel and Power, together with a large number of press reporters, attended the launch event for a nuclear-powered car. The car did not appear and its inventor claimed it had been sabotaged. Later he was found guilty of fraud: the car never existed. Since then, several more designs for nuclear cars have been proposed, including a thoriumpowered model designed in 2009 for Cadillac/General Motors (Figure 2).