Can nuclear power be used for cars?

Yes in principle, but not in practice: with today’s and foreseeable technology, nuclear power is not viable, safe, or legal for passenger cars. While fission packs enormous energy into tiny amounts of fuel, the reactors and shielding needed to make it safe would weigh many tons, far beyond what a road vehicle can carry. Instead, the realistic role for nuclear in mobility is indirect—using reactors to generate low‑carbon electricity and hydrogen that power cars, trucks, and trains.

What a “nuclear‑powered car” would actually entail

To propel a car, a nuclear system must deliver continuous power comparable to a modern drivetrain (roughly 50–150 kW for a car, 200–500 kW for a heavy truck), survive crashes, and shield occupants and bystanders from radiation. Three routes are often discussed: a compact fission reactor, a radioisotope power source (like those used in deep‑space probes), or, someday, fusion. Each faces fundamental hurdles that road vehicles cannot reasonably overcome.

Compact fission reactors: powerful, but far too heavy and complex

Modern “microreactors” under development for remote power—typically 1 to 20 megawatts electric—are engineered with robust neutron and gamma shielding, fail‑safe control systems, and thermal conversion equipment. Even the smallest concepts, using dense fuels like TRISO and advanced coolants, end up weighing tens of tons once you include reactor vessel, heat exchangers, turbine or Stirling equipment, radiation shielding, and containment. For reference, early transportable military reactors from the 1960s weighed on the order of 30–100 tons; current transportable designs for bases still target multi‑ton modules. A passenger car’s total mass budget is roughly 1.5–2.5 tons.

Beyond mass, the regulatory burden of licensing an operating reactor in every moving vehicle, the consequences of crash damage, and the need for secure fueling and decommissioning make on‑car fission reactors incompatible with public roads.

Radioisotope power (RTGs and betavoltaics): safe-ish, but far too weak

Radioisotope thermoelectric generators (RTGs) produce steady power by converting heat from decay—great for spacecraft, terrible for cars. State‑of‑the‑art space RTGs deliver on the order of 100–300 watts electric, whereas a compact car under highway load demands tens of thousands of watts. “Nuclear batteries” such as betavoltaics or diamond batteries deliver microwatts to milliwatts—useful for sensors, not drivetrains. Scaling them up would require prohibitive amounts of radioactive material and shielding.

Fusion: an enticing future, not a near‑term automotive option

Even optimistic fusion roadmaps envision first‑of‑a‑kind grid units later this decade or next, at building scale. Compact, crash‑worthy, low‑radiation fusion suitable for cars would still require neutron shielding, high‑field magnets or lasers, and heat‑to‑power conversion, pushing mass and complexity far beyond automotive limits. If fusion matures, its role—like fission’s—will be to supply low‑carbon electricity and fuels, not to sit under a hood.

Safety, regulation, and public acceptance

A roadworthy nuclear car would need to remain safe in collisions, fires, and submersion while meeting stringent dose limits for occupants, first responders, and the public. It would also need tamper‑proof fuel systems to deter theft or misuse of nuclear material, resilient containment for life‑cycle handling, and insurability. Transporting and operating thousands or millions of mobile reactors through cities would present a regulatory and emergency‑response challenge orders of magnitude beyond today’s nuclear rules—practically a non‑starter.

What history tells us

The following examples illustrate how nuclear propulsion has succeeded only in very large, heavily shielded platforms—or remained on paper—reinforcing why road cars aren’t feasible.

• Ford Nucleon (1958): a styling exercise imagining a swap‑in “reactor pack.” It never advanced beyond concept art because shielding and safety made it impossible at car scale.
• US and Soviet nuclear aircraft programs (NB‑36H, Tu‑95LAL): flew with onboard reactors to study shielding, but never produced operational planes; weight and safety issues were insurmountable.
• Military and civilian ships and submarines: nuclear propulsion works where displacement can run into thousands of tons, allowing thick shielding and ample space for turbines and safety systems.
• Transportable microreactors (e.g., DoD’s Project Pele; commercial efforts by Oklo, Westinghouse eVinci, X‑energy): designed to be moved by truck and then operated as stationary power plants in remote locations. Even these multi‑ton systems target base power, not vehicle propulsion.
• Nuclear locomotives and trucks: periodically proposed through the decades, but none entered service due to mass, shielding, and safety constraints.

Taken together, the record shows nuclear power can propel very large platforms or supply stationary power in remote areas, but it does not scale down to crash‑worthy, road‑going vehicles.

The physics wall: why shielding kills the idea

Fission’s energy density in fuel is extraordinary, but the system‑level power density is not. A road vehicle would need at least tens of centimeters of hydrogen‑rich materials for fast‑neutron moderation/absorption and dense metals for gamma shielding, encasing a reactor core and heat‑to‑electric machinery. Even with advanced fuels and compact cycles, the biological shield alone would weigh many tons—before adding turbines, radiators, controls, and containment. That mass penalty overwhelms any fuel advantage.

Could it ever work for road vehicles?

Outside of speculative far‑future breakthroughs in ultra‑compact, near‑aneutronic fusion (which does not exist today), the answer remains no for passenger cars and on‑road trucks. Some niche military concepts have explored reactor‑powered forward bases or tethered equipment in austere environments, but not propulsion on public roads. For mining or polar operations, the sensible approach is a site microreactor supplying electricity or hydrogen to conventional vehicles.

The realistic link between nuclear and transport: indirect use

Where nuclear can transform mobility is by decarbonizing the energy that vehicles use. The following points summarize the most practical pathways.

• Grid power for EVs: Firm, low‑carbon electricity from nuclear plants can charge electric cars and trucks, complementing variable wind and solar and supporting overnight charging without carbon emissions.
• Hydrogen production: Nuclear reactors can provide steady electricity—and potentially high‑temperature heat—to produce low‑carbon hydrogen via electrolysis, feeding fuel‑cell vehicles or refining and fertilizer demand.
• Synthetic fuels: Nuclear electricity and heat can drive production of e‑fuels (using captured CO2 and green hydrogen) for aviation, shipping, and legacy engines where batteries are impractical.
• Grid stability: Nuclear’s capacity factor supports reliable charging infrastructure, improving the resilience of electrified transport.

These indirect routes leverage nuclear’s strengths—reliability and low emissions—without the mass, safety, and regulatory pitfalls of putting reactors on wheels.

Bottom line

Building a nuclear car is theoretically imaginable but practically unworkable. The combination of shielding mass, crash safety, licensing, security, and cost rules it out for road use. The smart path is to let reactors stay put and use their clean power to run vehicles at a distance.

Summary

Nuclear power will not drive passenger cars directly: reactors small and light enough to fit safely in vehicles do not exist, and the safety and regulatory barriers are prohibitive. Nuclear energy’s real role in transportation is indirect—supplying low‑carbon electricity, hydrogen, and synthetic fuels that can decarbonize mobility at scale.

Why don’t we use nuclear energy for cars?

We don’t use nuclear energy for cars primarily because of the extreme weight and cost of the necessary radiation shielding, the engineering challenges of miniaturizing a reactor and managing its waste, and the significant safety risks, especially in a road accident scenario. Nuclear reactors are too heavy and complex to scale down for individual vehicles, making them impractical for personal transportation. 
Weight and Shielding:

• Heavy Shielding: To protect people from radiation, a nuclear reactor requires massive amounts of dense shielding material like lead or concrete. 
• Impractical Weight: This shielding would add tons to the vehicle’s weight, making it unmanageable and extremely difficult to move. 

Engineering and Safety Concerns:

• Miniaturization Difficulties: Nuclear reactors are not designed to be small and compact; scaling them down to fit into a car is a major engineering hurdle. 
• Waste Management: The radioactive waste generated by a car’s nuclear reactor would pose significant disposal and management challenges. 
• Accident Risks: A traffic accident involving a nuclear-powered car could lead to the spread of toxic radioactive materials, posing a severe contamination risk to the public. 
• Energy Conversion: Nuclear reactors generate thermal energy, which needs multiple steps of conversion to produce the mechanical energy needed to power a car. This process is complex and generates a lot of excess heat that would need to be managed. 

Cost and Feasibility:

• Prohibitive Costs: The research, development, and construction of nuclear-powered cars would be astronomically expensive, making them unaffordable for consumers. 
• No Clear Advantage: Given the massive challenges, the potential benefits of a nuclear-powered car do not outweigh the practical and safety concerns for this type of application. 

For these reasons, nuclear reactors are better suited for large, fixed installations like power plants, or for specialized applications like submarines and spacecraft where their size and weight are less of a constraint.

Why don’t we use nuclear fuel?

Nuclear energy produces radioactive waste
A major environmental concern related to nuclear power is the creation of radioactive wastes such as uranium mill tailings, spent (used) reactor fuel, and other radioactive wastes. These materials can remain radioactive and dangerous to human health for thousands of years.

Are nuclear-powered cars possible?

Nuclear-powered cars are not possible with current technology due to the impractical size, weight, and safety challenges of miniaturizing a nuclear reactor and its shielding to a vehicle-appropriate scale, though the concept was explored in mid-20th-century concept cars. Instead of an onboard reactor, the most feasible way to utilize nuclear energy for cars is to power electric vehicles (EVs) by charging them with electricity generated from nuclear power plants. 
Challenges of Onboard Nuclear Reactors

• Size and Weight: Nuclear reactors are large, heavy, and require substantial shielding to protect from radiation. These components would make a vehicle impractically large and heavy for road use. 
• Safety: A nuclear reactor in a car would pose significant risks in the event of a collision, with a possibility of radiation leaks or overheating. 
• Low-Power Density: While a single kilogram of uranium can power a large vehicle for a very long time, a car’s power needs are high, and the energy produced by small-scale power sources, like radioisotope thermoelectric generators (RTGs), is far too low for this application. 

Alternative: Nuclear-Powered EVs 

• Electric Grid: Opens in new tabNuclear power is a source of low-carbon electricity, so driving an EV charged with this electricity provides a clean transportation alternative.
• Hydrogen Production: Opens in new tabNuclear energy can be used to produce clean hydrogen from water, which can then power a car’s fuel cell.
• Synthetic Fuels: Opens in new tabNuclear energy can also power the production of synthetic fuels that have the same composition as gasoline or diesel, offering another pathway to a nuclear-powered transportation future.

Historical Concepts 

• In the 1950s, companies like Ford explored the concept of nuclear-powered cars, such as the Ford Nucleon and Seattle-ite XXI concepts. These visions of a nuclear-powered future, however, were not realized due to technological limitations, particularly the challenges of creating a sufficiently compact and safe reactor for an automobile.

How long would uranium power a car?

So if you burn 1 gallon of Petroleum liquid (gasoline) to make electricity you make 12.5kWh. My electric car gets 4 miles/kWh. So you can go 50 miles or 50 MPG. So 1 KG of uranium would take you about 1.3 million miles in an electric car.