Back in the 1950s, under the threat of communist apocalypse, the US military had plans for a long-range bomber using the energy of nuclear decay heat to stay aloft for weeks at a time. The Convair X-6 was a design to use a radical, high-temperature, molten-salt-fueled-and-cooled reactor (MSR), and made nuclear-powered aviation come quite close to reality. This program, called NEPA (Nuclear Energy for the Propulsion of Aircraft), like its space-faring cousin-project NERVA, was ultimately a sink for around 7 billion US taxpayer dollars before it was cancelled by Eisenhower. But it actually resulted in the development of a radical type of reactor (MSR) that still could be used to safely generate massive amounts of electricity. More on that later.
The Convair X-6 bomber prototype, which carried a working nuclear reactor and heavy radiation shielding for the pilots (105,000 pounds of lead alone), was test flown nearly a dozen times in 1957.… Read the rest