Many governments around the world seem to be on a very real mission to send internal combustion engines (ICE) to an early grave. This is for a variety of reasons, but since most of the infrastructure that underlies our civilization is, quite literally, powered by fossil fuels, such a transition must be done relatively gradually and well planned.
One solution is to replace ICE-powered vehicles with electrical vehicles (EVs). While a sound solution on the surface, this technology is not yet in a position to replace the convenience, and cost, of all ICEs.
But there is one potential technological avenue that might be worth exploring, well re-exploring, nuclear-powered cars! If you are a fan of the Fallout series of computer games, or the "Back to the Future" series of films, we hope we've now got your attention!
For everyone else, let's explore the possibility, if only as a thought experiment.
Could nuclear reactors ever be made to fit inside a car?
Believe it or not, theoretically, it is quite possible. What's more, it has even been considered in the past, sort of.
Meet the 1958 Ford "Nucleon."
Conceived at the height of nuclear fever in the 1950s, the "Nucleon" was a sort of thought experiment - a concept for cars that could theoretically be made to run for more than 5,000 miles (over 8,000km) without needing to refuel.
Sadly, the technology needed to make such a car a reality was far beyond the engineers of the day. To this end, it never left the drawing board.
The "Nucleon" would have been, if ever built, 16.7 feet (5.09m) inches long and 6.45 feet (1.97m) wide, making it about as long as the Ford Maverick compact pickup, but ever so slightly wider. The roof of the car would have stood about 3.45 feet (1.05m) inches from the ground, making it just a tad taller than a Ford GT40.
Its wheels were also pretty close together to, presumably, support the presumably heavy weight of an onboard nuclear reactor.
As for the power source, Ford envisaged something called a "power capsule" that would sit in the "trunk" of the "Nucleon." According to their design of the time, this reactor would be easily serviced and refueled, and would generate power to move the car via "electronic torque converters."
While this seems extremely wild as a concept today, back at the time with nuclear power coming online for the first time, it would likely have felt like just a matter of time before things like cars would also be powered the same way.
However, even the "Nucleon" was something of a latecomer to the idea. Engineers, as it turns out, have been proposing nuclear-powered vehicles since around 1903. In 1941, for example, Dr. R. M. Langer, a Caltech physicist, explored the idea of a uranium-235 powered vehicle in the January Edition of Popular Mechanics.
But, just like today, shrinking a nuclear reactor to the size needed for an automobile was deemed to be very technically challenging. Perhaps prohibitively so.
But not necessarily for the reasons, you may think. It is not so much about making a small reactor for a car, but more about managing, safely, the sheer amount of energy a nuclear reactor can generate.
"The reactor core itself (including shielding) for a small nuclear reactor could indeed fit into the engine compartment of a personal vehicle, which would generate ample energy to power a personal vehicle," Dr. L. Dale Thomas, Deputy Director of the Propulsion Research Center at the University of Alabama in Huntsville said in an interview with The Drive.
"However, the difficulty arises from the energy conversion problem. The nuclear reactor will generate thermal energy, which needs to be converted to mechanical energy."
And this process tends to require quite a few energy-type conversions to work effectively. Full-scale nuclear reactors generally work by effectively turning water into steam (thermal energy), which is then used to turn a steam turbine (thermal to mechanical).
This steam turbine is, in turn, used to produce electricity. If shrunk to fit into a car, an extra conversion would be needed to turn electricity back into mechanical energy via motors. Each step in this process introduces inefficiencies and energy loss (usually as heat) at every step. This could prove very problematic for a true nuke-car - most notably how to deal with all that excess heat.
In an internal combustion engine, waste heat is removed from the system via the exhaust gases and engine radiators. The heat needed to be removed from a nuclear reactor cannot simply be dumped into the environment, so would need to be dealt with another way.
This would likely require a large array of closed-system heat exchangers acting similar to air-pump air conditioning systems. Such a setup would add extra weight and "parasitic loss" to the electrical systems of the car.
They might also seriously impact the aesthetics of the vehicle, but this is a secondary consideration.
For these reasons, nuclear power on the small scale of a personal car simply wasn't possible back in the day, certainly not at the scale of mass production seen in modern cars.
"Mobile nuclear power on such a small scale was not feasible in the '50s," Dr. Thomas explained. "And not due to the small reactor itself, which we do now understand how to construct and control—refer to NASA's KRUSTY project—but rather the thermal-to-mechanical energy conversion and disposal of waste heat within the geometrical envelope of a personal vehicle. Also, with the Department of Energy's Small Modular Reactor Program, the nuclear industry is figuring out how to mass-produce nuclear reactors."
At the time of the "Nucleon," many scientists and technologists likely assumed that this problem could be solved fairly quickly. However, scaled-down energy conversion technologies like those needed here still elude us today for the most part.
As for the look of the "Nucleon" it, like the concept as a whole, was, well, just a concept.
Why don't we have any nuke-powered cars?
One of the main reasons is the amount of shielding needed to prevent the vehicle's occupants and the general public from receiving fatal levels of radiation. This is a very serious technical challenge and one we will explore a little later on.
Shielding aside, nuclear technology has improved greatly since the 1950s, so could we build a nuclear-powered car today?
As it happens, a more up-to-date proposal for a nuclear car was made back in 2009. Called the Cadillac World Thorium Fueled Concept Car it could, according to its designers, theoretically run for over 100 years with little to no maintenance.
The concept car was debuted at the 2009 Chicago Auto Show, but only as a display piece - there was no working nuclear reactor was under the hood. Thorium would be a good choice as it is less radioactive and more plentiful than other nuclear fuels like uranium. In fact, some modern designs for micro-nuclear reactors are based on using thorium as a fuel. These reactors, while small, are still not compact enough to fit inside the chassis of a personal car, however.
Another potential approach, however, is being explored by Charles Stevens, a researcher at the Massachusetts R&D firm Laser Power Systems. His proposal was to develop a thorium-powered laser that can be used to generate enough energy to power a vehicle while producing zero emissions.
Stevens apparently managed to produce a prototype system using a proprietary high-intensity "MaxFelaser" laser that is fueled by thorium.
According to information available on the system, it works by using the laser beam to evaporate water into pressurized steam, which spins a turbine and generates electricity. This electricity can then be used to power motors for propulsion - just like in EV cars.
Steven's system could produce a total of 250 kilowatts (equivalent to 335 horsepower), would weigh about 500 pounds (227kg), and be small enough to fit under the hood of a car. Impressive, but the lack of thorium-laser-powered cars on the road seems to indicate that it never really took off.
But there could be another approach. Let us introduce the idea of the "atomic battery."
Could we use "atomic batteries" to power a car?
Instead of sticking a tiny nuclear reactor inside a car, we could, instead, think outside of the box a little.
An "atomic battery" relies on the steady decay of nuclear isotopes (rather than a chain reaction) to produce a smaller, but constant, supply of electricity. They also produce little to no waste, and could, actually, use nuclear waste as a fuel source.
While they are termed "batteries," they are not electrochemical in nature, and cannot be recharged (obviously). These kinds of "batteries" have an extremely long life and very high energy density.
Unlike other concepts discussed above, this technology already exists and is a proven technology. They are, for example, quite common power sources in spacecraft. This is an excellent choice, as "atomic/nuclear batteries" have a very long lifespan and are very durable. But, they are not cheap either.
Interestingly some private sector enterprises, like NDB Technology, are looking at ways to develop this technology further.
Their concept "nuclear nano-battery" uses recycled nuclear waste, with multiple layers of a strong synthetic diamond coating for protection to make very small nuke batteries. According to the company, "The energy is absorbed in the diamond through inelastic scattering, which is used to generate electricity." Some of these batteries could even be made small enough to fit inside small electronic devices like smartphones.
This amazing piece of tech could, according to NDB, last up to 28,000 years as well! Incredible.
If ever fully fleshed out, this is excellent news for any budding nuclear car inventor. If these batteries can be made to fit in something like a television or phone, they could certainly be made large enough to power an entire car.
Of course, to actually break into the market, manufacturers would need to get over the very serious handicap of the public perception of danger and distrust of nuclear power.
For the nuclear industry, such a development would also be fantastic news, as their waste could then become someone else's asset.
It would also effectively make the industry much more efficient, as everything is utilized, even the waste. Governments would also be likely to get behind such an initiative as, instead of having to spend taxpayers' money on "disposing" of the waste, they could give it to a company or automaker needing the waste for their car or product.
Everyone wins, especially the environment.
Could nuclear be the holy grail for the EV market?
As interesting as the above potential solutions are, the future of nuclear use in vehicles might be something quite different. Instead of onboarding nuclear reactors to a car, might it be a better solution to use nuclear to charge EVs instead?
Especially large electrical vehicles like trucks?
Trucks are considerably larger vehicles than cars and, therefore, require much more power to keep them moving. While internal combustion engines have proved invaluable for this in the past, there is growing pressure to make trucks more "green" through the use of all-electric power trains.
But there is a very serious problem. Electrical trucks will need much more juice than a small EV car.
In some instances, electric trucks require something in the order of five to 10 times more electricity than an equivalent electric car. For this reason, any realistic proposal for an all-electric truck would need to have access to an abundant source of power. And in order to be green, this power would need to be generated from a clean source of fuel - not a fossil fuel power station.
This is especially true for freight vehicles that often make long-distance hauls most days of the week. While this could conceivably be achieved through regular pit stops to top up an onboard battery, freight vehicles are often required to travel to remote places that may, or may not, have recharging points.
Or if they do exist, they may not have the capacity needed for something as energy-thirsty as a large truck. This is where a micro-nuclear reactor could really come in handy.
As Foro Nuclear explains, "the concept of small-sized nuclear reactors is not new. There have been small reactors for some time now, generating electric energy in remote areas [the Arctic, military bases, space ships (see the monograph Nuclear Power & Space Exploration)] for years without having to recharge. These designs are the result of over 20 years of research at the United States Department of Energy (DOE), with mature and proven technologies that guarantee nuclear safety."
For powering EV trucks, microreactors of this kind could prove to be a godsend.
In fact, engineers at the Argonne National Laboratory (ANL) in Illinois have been working on an interesting design for a micro-nuclear reactor that could eventually be installed at many rests stops around the world. These reactors would be more than capable of generating the power needed to recharge something like an 18-wheeler truck in short order.
Known as MiFi-DC (MicroFission Direct Current), these reactors could someday be used to recharge transport trucks at thousands of rest stops around a country like the US, or even the world. Each reactor is roughly the size of two home water heaters and is connected to an energy storage system.
Such reactors are relatively simple pieces of kit and could prove to be fairly cheap to build and install. Unlike other methods of energy production, they also have some interesting inherent advantages.
The first is their flexibility. Micronuclear reactors would be able to provide a very stable electrical supply that can readily adjust to demand. For times when power is not being drained from the system, heat can be stored in an annexed storage site, using an inert fluid, ready for use later on.
When the rest stop is busy, the system could access this hot fluid to produce steam and generate electricity as and when needed.
The other advantage, and most important from a nuclear point-of-view, is their inherent safety. These reactors use a special type of nuclear fuel that keeps all the radioactive material isolated from any outside contact. The fuel in question is composed of tri-structural isotropic pellets (TRISO), developed after 60 years of research at the DOE national laboratories.
These tiny pellets contain low enriched uranium covered by several layers of carbon and ceramic-based materials. It is these protective layers that prevent the release of radioactive fission products.
TRISO fuels are much more structurally resistant to neutron irradiation, corrosion, oxidation, and high temperatures than traditional reactor fuels. Each particle effectively acts as its own containment system. This allows them to retain fission products under all reactor conditions.
Small reactors using TRISO pellets can also, according to Derek Kultgen, senior engineer at the Nuclear and Science and Engineering at the Argonne National Laboratory (ANL), operate for over ten years. This is not insignificant and could result in very cheap charging costs for large vehicles like trucks over the long term. Perhaps even make it competitive, or cheaper, than fossil fuels.
The ANL team indicated that this project could fill the current gap in the recharging infrastructure for electric long-haul vehicles, the 18-wheelers, although there is still a lot of work to do.
What could possibly go wrong with nuclear-powered vehicles?
For any fan of nuclear power, the above is all very good news. But, like anything in life, there are some potential downsides to this technology - as you'd expect.
The first is that they would need to be the epitome of safety. Since the power source is highly radioactive, measures will need to be taken to prevent exposure of occupants and the public at large before we could even begin to consider rolling out this technology. The short- and long-term effects of exposure to radiation are now well studied and well-known, so limiting this to as much as reasonably practicable would be a must.
But how much would be an acceptable maximum limit? After all, bulky shielding would mean more weight to the vehicle and add limits on the aesthetics of the car.
Well, according to the Canadian Nuclear Safety Commission, doses of over 1,000 millisieverts (mSv) will likely cause symptoms of radiation sickness. Nuclear energy workers typically receive 50 mSv a year working in nuclear power plants.
The general public is usually subject to about 1 mSv a year from various environmental sources like cosmic radiation exposure, but this can be elevated in areas with high radioactive geology (like high levels of radon gas). It is this value that most health authorities will set as the "effective dose limit" for the general public.
So, this would be a natural industry standard for any potential nuclear-powered cars of the future. Depending on the type of nuclear-power source chosen, this could mean that nuke-cars would need to be pretty big things to provide the required amount of shielding.
They may also be pretty bulky or large cars akin to the Cadillacs of the 1950s to 1970s. Most of such a car's size would be located to the front or rear, depending on the location of the nuclear material, with all the maneuvering and parking implications a large car has.
If nuclear batteries could be developed to power an automobile, however, this "issue" might become moot.
In all cases, however, the primary safety issue would be the car's survivability (well the reactor) during a crash. Any serious crash could result in a very serious miniature nuclear contamination disaster. Not ideal to say the least, especially considering the number of serious crashes each year. Not to mention the need to protect nuclear fuel from abuse by potential terrorists.
This could, in fact, prove to be an insurmountable potential problem for any genuine nuclear-powered vehicle proposals in the future.
What are some of the most notable nuclear-powered cars ever designed?
We've already highlighted a few of the most notable examples of nuclear-powered car proposals above, but there are several others too.
Here are some of the most interesting, and frankly, fun examples. This list is far from exhaustive and is in no particular order.
1. The Arbel-Symétric almost went into production
One interesting example of a proposed nuclear-powered car was the Arbel-Symétric. Originally designed as a hybrid vehicle, its first iteration had a regular gasoline engine that generated electricity for the car's four hub-mounted electrical motors.
Sadly for the designer of the car, this was met with little interest and was soon abandoned. However, the car was further developed and was showcased at the 1958 Geneva Motor Show.
Most interesting of all was the fact that it was advertised with various alternative power sources including a 40KW turbine and, amazingly, a 40KW "Atomic Battery" variant. What's more, the battery would have used nuclear waste.
Sadly, Arbel couldn't get permission from the French Government to use nuclear fuel, so the project was dropped and Arbel went into bankruptcy soon after.
2. The Ford Seattle-ite XXI was another interesting concept
Another interesting concept for a nuclear-powered car was the Ford Seattle-ite XXI. Only ever developed as a 3/8 scale, non-working model, the vehicle was designed by Alex Tremulis and was showcased at the 1962 Seattle World's Fair.
Amazingly, the vehicle included some novel ideas that have since become a reality in other vehicles. This included things like interchangeable fuel cell power units; interchangeable bodies; interactive computer navigation, mapping, and auto information systems; and four driving and steering wheels.
But, from our point of view, the designer proposed that the car would be powered by a form of compact nuclear propulsion device. This, of course, assumed that the issues of sufficient shielding and heat exchange could be developed that would not make the vehicle prohibitively bulky and heavy.
The car had six wheels, four of which would have been turntable, similar to the famous FAB1 car in Thunderbirds and the real Tyrrell P34 racing car developed in the 1970s.
It is a real shame this car never saw the light of day.
3. The 1958 Simca Fulgur really looked the part
Clearly a product of its day, the Simca Fulgur was another proposed nuclear-powered car that would never hit the road. A French design, the vehicle had a plastic bubble top and hidden wheels, giving it an almost alien appearance.
Never seriously intended for production, the concept was unveiled at the 1959 Genera Auto Show. Touted as potentially being nuclear-powered, the proposed vehicle would have been voice-controlled and guided by radar.
Also showcased at the New York Auto Show and 1961 Chicago Auto Show, the vehicle only had two wheels and was balanced using specially designed gyroscopes.
4. Meet the 1957 Studebaker-Packard Astral that would have had an energy shield
Making its debut in 1957, the Studebaker-Packard Astral was another, never developed, nuclear-powered concept car. Completely balanced on one wheel (using a gyroscope for its balance, of course), this vehicle's design really was something completely different.
Apparently, the vehicle would have been equipped with some form of energy shielding to protect the driver and passengers from any radiation kicked off from its onboard nuclear reactor power plant. This shielding would also have offered vehicle collision protection too.
Studebaker-Packard didn't survive long enough to see any of the features of its wild concept car come to fruition, however. Packard shut shop a few years after the Astral was released, followed close behind by Studebaker.
After that time, the concept car would make appearances in other dealership events before finding its way to its final resting place at the Petersen Automotive Museum in Los Angeles.
And that nuclear-powered vehicle enthusiasts is your lot for today.
While nuclear power is commonly used on large modes of transportation like warships and submarines, the technical problem of safely miniaturizing reactors, and frankly, lack of enthusiasm, have prevented its introduction into personal vehicles like cars.
But, with the push to decarbonize many aspects of the global economy, could nuclear power provide some answers when it comes to transportation?
Whether nuclear power plants could be miniaturized enough to fit under the hood of cars or be used to provide power for recharging EVs, nuclear power could be an excellent solution for all concerned.
However, like anything nuclear power-related, this will take some very serious public relations work to overcome years of bad press. We shall see.