|Fig. 1: HTRE 1 and HTRE3: prototypes of aircraft-based nuclear reactors . (Source: Wikimedia Commons).|
Nuclear energy has emerged as a realistic power source for power plants, ships, and even submarines. Yet, despite great effort, the nuclear energy revolution has yet to reach aviation. The idea of a nuclear powered airplanes, able to fly for days, weeks, even months at a time without landing, captured the minds of scientists and government officials from the very earliest days of the nuclear era.  In fact, the US Air Force launched the Nuclear Energy for the Propulsion of Aircraft (NEPA) in 1946, five years before the first successful nuclear reactor had even reached completion.  While several engines were built and tested, including HTRE 1 and HTRE 3 (see Fig. 1), no American aircraft ever flew on nuclear power, and the program was shut down by Kennedy in the early 1960s.  Meanwhile, the Soviet Union had launched their own program in the 1950's. While the Soviet program ultimately culminated in the creation of the Tupulov Tu-97, which flew several test flights in the early 1960's, it too was shut down by the end of the decade. 
Despite massive potential and large investment, both the American and Soviet programs for nuclear powered aircraft had been terminated by 1970. Several factors played a role in this demise. Ultimately, the strategic role of the nuclear airplane (permanently ready to strike at first notice) was filled by ICBM's and nuclear submarines.  Had the aviation programs succeeded earlier, they might have gotten traction and played a much larger role. But several technical pitfalls, such as protecting the crews from radiation and guaranteeing safety in case of a crash or mid-air accident, plagued the early prototypes. 
Yet today, fifty years since the last serious efforts, nuclear aviation appears on the horizon once again. Indeed, Spanish designer Oscar Vinals has already designed a future nuclear-powered commercial airline, dubbed the "Flash Falcon."  The revolutionary plane would fly faster than the Concorde, but it relies on a small fusion reactor for power.  Groups at MIT and Lockheed Martin seem to be making some progress on the development of such a reactor. Lockheed Martin claims their reactor will create enough energy to power a small city and that it will be ready within the next ten years.  Should these efforts pan out, the idea of such power generators on airplanes may once again rise to prominence. Nevertheless, it is overwhelmingly likely that nuclear aircraft will remain a fantasy, at least in the near future. Nuclear fusion, the holy grail of nuclear energy, has been pursued for decades now without serious breakthroughs. Even if such power did exist, the same issues (safety, weight, radiation) that plagued early aviation efforts will continue to pose barriers to modern attempts.
© Scott Morris. The author grants permission to copy, distribute and display this work in unaltered form, with attribution to the author, for noncommercial purposes only. All other rights, including commercial rights, are reserved to the author.
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