Nuclear planes and wiener roasts

There is a persistent urban myth that there exists an airstrip four miles long in the Arco desert in Eastern Idaho. While that strip does not exist, it is understandable why people think it does given that the project it was intended for seems so insane — a nuclear-powered airplane. Just about anyone with even a passing knowledge of the INL site knows about the two large reactors parked south of US-26 next to EBR-1. They are vestiges of the failed 1950s Aircraft Nuclear Propulsion (ANP) Program.

The popular story says that the pseudo-secret program “even got the huge airstrip built before someone realized how crazy the idea was and shut it all down.” That has just enough of a conspiratorial “the government is run by lunatics” flavor to it for the average American to chuckle, nod and believe it, but the facts are even stranger than that and well worth remembering.

In the late 1940s and early ’50s the world was abuzz with the potential of nuclear power. It was a decade before the nation’s first deadly nuclear meltdown at the Army’s SL-1 and every magazine looked like a comic book full of futuristic drawings. Endless, cheap and safe nuclear power seemed poised to solve the world’s problems in a flurry of Buck Rogers technology. Well, at least that was the view outside the Pentagon. Inside the Pentagon, endless, cheap and horrifically destructive nuclear power seemed poised to defeat all of America’s enemies in a flurry of mushroom clouds.

The problem for the military was that there was no telling when they might suddenly find themselves in need of obliterating an enemy with a thermonuclear device. What’s the point in having a nuclear bomb if you just got bombed by a nuclear bomb and your nuclear bombs were still sitting on the runway (which was probably the first place nuked)? The answer was to have bombers “on station” flying endlessly in the skies ready to strike at a moment’s notice. That of course brought up problems with fuel. Mid-air refueling was a partial answer, but was ridiculously expensive. So, the Air Force got to thinking maybe a nuclear reactor could be used to power an airplane for a much longer time.

The ever-optimistic Air Force went all-in, even to the point of coining a catch phrase. “Fly early!” was their rallying cry and they meant to have a nuclear-powered aircraft in the sky in only five years. After all, how hard could it be? Never mind that a few know-it-alls like that guy J. Robert Oppenheimer said it was stupid. What did he know anyway? All the problems and objections seemed easy enough to solve if the Department of Defense (DOD) and the Atomic Energy Commission (AEC) just threw enough money into the program.

Despite the myth, the Air Force, DOD and AEC were aware of the safety issues. It was just that the Air Force and DOD thought the AEC were a bunch of scaredy-cats. So, the money came in fits and starts, but by the end of 1955 the Air Force had a prototype. Dubbed Heat Transfer Reactor Experiment (HTRE-1), it was known at the site as “Heater One.” It was an apt description. The principle was to superheat air using nuclear power and use that air to drive a jet engine. HTRE-2 (using components from HTRE-1) and HTRE-3 soon followed.

As Susan Stacy says in her book, “Proving the Principle,” “In a conventional airplane, the combustion of chemical fuel produces heat. Hot compressed air passes through a turbine and is exhausted through an opening (nozzle) at the rear of the aircraft. ... The function of a nuclear reactor was to produce heat, replacing the combustion chamber. It would have to fit within an airframe and generate extremely high temperatures. Shielding to protect the crew had to weigh as little as possible, or the plane couldn’t get off the ground.”

There were two ways of getting the heat from the nuclear reaction to the air in the engine, either by pulling air directly through the reactor or by pulling air through a liquid metal heat exchanger. GE got the contract for the first option which was to be tested in Idaho.

It is at this point we should pause the history and declare the absolute lunacy of this idea. What GE was charged with making was a nuclear reactor that was designed to have minimal shielding, high energy output and actively draw air through the core to be exhausted into the atmosphere! Admittedly, the end use of such a reactor was to nuke the enemy and that would put out a lot of radiation, too.

Still, while the environment was not really something the Air Force cared about, their pilots were because flight crews you would trust with nukes and a nuclear reactor are pretty expensive to make. Also, GE needed to keep their scientists and engineers alive during development. So the project did bow its head to some nominal safety requirements, but the AEC was a constant thorn in the side of the development team.

The project location at the site was dubbed Test Area North (TAN) and was the scene of amazing engineering efforts just to get the prototypes tested. First, an aircraft needs a hanger and the hanger for an aircraft is designed for the expected size of the airframe. In this case, the hanger was 320 feet by 234 feet. The aircraft was slated to have a wingspan of 135 feet, be 205 feet long and have a tail 53 feet high.

Unlike a normal hanger, though, this one had some additional requirements. The planned bomber was pretty much a bare reactor with the pilots sealed in a shielded crew compartment. This meant the plane itself would be dangerously radioactive. So, the idea was to have the crew exit via a lead-brick-lined hatch into a tunnel in the floor of the hangar. Then they could travel to decontamination.

The plane’s reactor was also planned to drop out of the airframe, then transported via elevator to the basement and then moved to a “Hot Shop” for repair and maintenance. This procedure was to be accomplished by a worker in a miniature shielded tank, called “the Beetle,” with articulating arms attached to the turret.

Meanwhile, the contaminated fuselage would also need to be maintained by workers in radiation suits.

Before getting to that stage, though, the reactor would require mock-ups and testing outside of an airframe. To make that happen, they had to find a way to get the reactor to a special testing facility that was designed to filter out the radioactive particles exiting the engine. This facility was necessitated by the simple fact that GE could not keep their engine’s exhaust inside their fence and the Atomic Energy Commission’s Idaho Office (IDO) objected to GE spewing the Air Force’s radiation over Southeast Idaho’s populated areas.

To shuttle the test reactors between facilities, what is certainly the most unique railroad in the history of Idaho was built. The airplane reactors were designed to be mobile but were far from small, especially when attached to their test sleds to keep them anchored to the ground during testing. HTRE-3 stood 25 feet high, 40 feet long and 24 feet wide and weighed-in at 490,000 pounds. For comparison, the average railroad car carries about 65 tons and is less than half as wide. The solution was a railroad track with four rails to balance the load across all four tracks. Six lines spidered off a massive turntable not far from where SH-33 approaches TAN today. The longest track runs over a mile west to the large hangar.

Next, the engineers realized a typical locomotive would not work. Although it could ride the center two rails while pushing the test platform, the locomotive engineer would be exposed to high levels of radiation. So, the locomotive was designed to encase the engineer in a large radiation-proof cab. This contraption still exists and is on display next to HTRE-2 and HTRE-3. The domed cab is about 13 feet long, is lead and water shielded, and has thick leaded glass windows on the front and back so the engineer could see out. A 400-hp diesel-electric unit provided power which moved the test platform and reactor at about 5mph between buildings.

Early tests were encouraging and more practical questions began to be asked. For instance, what would happen if a nuclear-powered aircraft crashed and burned? To investigate that possibility the IDO conducted tests called “Operation Weiner Roast.” The first involved 500 gallons of jet fuel, some aluminum fuselage and a chunk of reactor fuel. When the 2,250-degree conflagration failed to release nuclear material into the air another test using an induction furnace was set up. That did the trick and a small amount of cesium-137 was released. The winds shifted the wrong way and sent radiation back to the site’s main work area, but reportedly not enough to be unhealthy for the employees.

At some point, plans were created for the fabled runway. Slated at 23,000 feet, it was never built but may have been staked out. Old runways such as the Big Butte strip and Midway at Atomic City are easy to see from the air, but nothing even close to a test runway like the one at Groom Lake in Nevada is apparent on the ground near INL.

The reason the airstrip was not built is because those pesky AEC scientists put their foot down and told the generals they would not be flying nuclear-powered aircraft over America where a crash would render the immediate area uninhabitable. The Air Force countered that the airplane would be escorted by other planes and if there was a crash they could blanket the area with foam. This time the scientists won out. The plan shifted to building and ground testing the airplane at one location (Idaho) and then disassembling it and moving it to the coast for reassembly and test flights over the ocean.

Another nod to safety was made when it was pointed out that most crashes occurred during takeoff and landing. So the aircraft was designed to be able to take off using conventional fuel and then switch to nuclear when cruising safely over the ocean. On return the plane could again switch to jet fuel so the core could cool before landing. Whether or not the Air Force intended to do this is another matter since they had proven they could cold start the engines using just the reactor. Still, having a backup plan was a nice idea.

After 15 years and over $1 billion, the program still failed to produce a nuclear-powered airplane. Meanwhile, much to the Air Force’s frustration, the Navy had gone from concept design to prototype of a nuclear submarine in a bit over 1,000 days.

Fed-up with the cost overruns and failure to deliver, on March 26, 1961, President Kennedy abruptly killed the Air Force’s program. As Oppenheimer and others predicted, the engineering problems were too great and aircraft carrying nukes were made largely obsolete by nuclear tipped Intercontinental Ballistic Missiles (ICBMs).

HTRE-2 and HTRE-3 were put in storage. Finally, in the late 1980s the process to decontaminate and decommission the reactors began. Not only were they radioactive, but they also had asbestos insulation and the water moderator in the annulus around the reactor was replaced with mercury when they were not operational. This trifecta of hazardous waste cost about $1.3 million to clean up.

Test Area North still has the previously mentioned 4-rail track lines and a nice hanger-sized storage facility, but there is no runway built for nuclear airplanes. The shielded locomotive, HTRE-2 and HTRE-3 all now stand on the west side of the INL site near EBR-1 for the occasional tourist to stare at while contemplating the mid-20th century military-industrial complex.