Impossible Inventions · Engineering

The Airplane That Carried a Nuclear Reactor

Imagine a bomber that never has to land — that could circle the globe for days or weeks without refueling, because it carries a nuclear reactor in its belly. In the 1950s, the United States spent roughly a billion dollars and fifteen years trying to build exactly that. It even flew a real reactor through the skies over Texas. It just never managed to make the reactor fly the plane.

· 5 min read · Filed under Engineering

The Airplane That Carried a Nuclear Reactor

What happened?

The dream began in 1946 with a project called NEPA — Nuclear Energy for the Propulsion of Aircraft — which in 1951 grew into the Aircraft Nuclear Propulsion (ANP) program, run jointly by the Air Force and the Atomic Energy Commission. The logic was pure Cold War: a nuclear-powered bomber could stay airborne almost indefinitely, an ever-present deterrent against the Soviet Union that never needed to come down to refuel.

Engineers pursued two approaches to nuclear jet engines, one at General Electric and one at Pratt & Whitney, both aiming to use a reactor’s heat instead of burning jet fuel. To study the staggering problem of shielding a human crew from a reactor just feet away, the program modified a giant B-36 Peacemaker bomber into the NB-36H. Between 1955 and 1957 it flew 47 times over West Texas and southern New Mexico with a small, operational reactor on board. This was the only time the U.S. ever flew an aircraft with a working nuclear reactor inside it.

Here’s the catch: the reactor aboard the NB-36H never actually powered the plane. It ran while conventional engines did the flying, purely to test whether the crew’s shielding worked. A flight-worthy nuclear engine was never finished. In 1961, President Kennedy canceled the entire effort, noting that “15 years and about

billion have been devoted to the attempted development of a nuclear-powered aircraft; but the possibility of achieving a militarily useful aircraft in the foreseeable future is still very remote.”

Why was it strange?

It’s the sheer audacity that lingers. Engineers seriously proposed flying tons of radioactive material over populated areas, and confronted nightmares that conventional aircraft never face: How do you shield a pilot from a reactor without making the plane too heavy to fly? What happens to the countryside if a nuclear bomber crashes? The crew of the NB-36H sat in a lead-and-rubber-lined cockpit weighing about 12 tons. The Soviets, not to be outdone, flew their own reactor-carrying testbed, the Tupolev Tu-95LAL.

What did scientists learn?

Beyond the hard limits of shielding and crash safety, the program ran headfirst into a strategic problem: by the time the technology might mature, it was obsolete. The first intercontinental ballistic missiles entered service in 1959, and a missile that can cross the world in half an hour made an always-airborne bomber far less necessary. The project is a clean lesson in how an engineering goal can be technically heroic and strategically pointless at the same time.

How does it affect us today?

The nuclear airplane never happened, but the research wasn’t wasted. The Aircraft Reactor Experiment built for the program was the first molten salt reactor ever operated — and that work fed directly into later civilian molten-salt reactor research at Oak Ridge, a reactor concept that’s seeing renewed interest today for safer, more efficient nuclear power. Some of the program’s decommissioned test reactors are now on public display in a parking lot at Idaho National Laboratory.

Fun fact

The same atomic-age enthusiasm spawned an even wilder cousin: Project Pluto, an effort to build a nuclear-powered ramjet missile designed to fly low and fast for weeks, spewing radiation in its wake. It, too, was abandoned — arguably for everyone’s benefit.

Sources

#nuclear aircraft #Cold War #NB-36H #atomic age #impossible inventions

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