Can a nuclear battery power a car?

In practical, legal, and safety terms today, no: existing “nuclear batteries” deliver far too little power to propel a road car, while compact nuclear reactors that could supply enough power are far too heavy, complex, and heavily regulated for passenger vehicles. Nuclear energy can, however, power cars indirectly by charging electric vehicles from the grid, and niche auxiliary uses may emerge in the long term.

What people mean by “nuclear battery”

The phrase covers a few very different technologies. Understanding them is key to assessing whether they could ever move a car down the road.

• Radioisotope power systems (RPS), including RTGs: They convert heat from the decay of isotopes like plutonium‑238 into electricity via thermoelectrics or Stirling engines.
• Betavoltaics/“diamond” batteries: Semiconductor devices that turn beta radiation (from isotopes like nickel‑63 or tritium) into tiny currents, prized for longevity rather than power.
• Compact fission reactors (“microreactors”): True reactors that maintain a fission chain reaction, producing kilowatts to megawatts, but needing substantial shielding and control systems.

These categories have radically different power densities and safety profiles. Only reactors reach car-scale power; radioisotope devices and betavoltaics are orders of magnitude lower, designed for decades-long trickle power in remote sensors and spacecraft.

How much power a car actually needs

Modern cars require sustained and peak power far beyond what radioisotope devices can offer. A quick look at typical numbers shows the gap.

• Typical highway cruise: roughly 15–25 kW for a mid-size EV at 100–120 km/h, depending on aerodynamics and terrain.
• Urban driving: lower average, but frequent peaks for acceleration.
• Peak power: 50–150+ kW for safe merging and hills is common in mass-market EVs.
• Energy use: about 15–25 kWh per 100 km for efficient EVs.

Even the low end of steady highway power (tens of kilowatts) dwarfs what nuclear batteries provide today, which are measured in milliwatts to a few hundred watts at best.

How nuclear batteries compare on power and practicality

Radioisotope generators (RTGs and Stirling)

RTGs have a long spaceflight track record, but their electrical output is modest. The Multi‑Mission RTG used by NASA’s Curiosity rover delivers on the order of 100–120 watts of electricity from roughly 2,000 watts of decay heat at the start of life; more advanced Stirling converters can improve efficiency to the low tens of percent but still don’t reach kilowatt levels without large, costly isotope inventories.

• Specific power of Pu‑238: about 0.5–0.6 W/g of thermal power; even with optimistic 20–25% conversion, 1 kg yields only around 100–150 W electric initially.
• To supply 10 kW electric, you’d need on the order of 70–100 kg of Pu‑238 plus converters, heat rejection, and robust containment—massive, exorbitantly expensive, and far beyond global supply.
• Heat management becomes a design problem: thousands of watts of continuous heat must be safely dissipated at all times, parked or moving.

These figures show that radioisotope systems are superb for longevity and reliability in deep space, but not for propelling a car that needs tens of kilowatts on demand.

Betavoltaics and “diamond” batteries

Recent headlines have featured coin-sized “nuclear batteries” promising decades of life. Their reality today is ultra‑low power designed for sensors, not traction.

• Typical outputs: micro‑ to milliwatts per cubic centimeter; recent public claims (e.g., 2024 announcements using nickel‑63) cite around 100 microwatts at a few volts in prototype form.
• Roadmaps touting watt‑level devices remain unproven at commercial scale as of 2025; peer‑reviewed demonstrations at such power remain scarce.
• Scaling to kilowatts would require vast radioactive inventories and create major radiation safety and regulatory hurdles.

Betavoltaics excel where battery replacement is impossible and loads are tiny. Their power density is far too low for vehicle propulsion.

Compact fission microreactors

Small reactors can make kilowatts to megawatts, so why not put one in a car? Physics and policy intervene.

• Shielding mass: stopping neutrons and gammas requires thick, heavy shielding (e.g., layers of steel, lead, and hydrogenous materials), adding tons of weight—fine for ships and submarines, not sedans.
• Complexity: reactors need control systems, containment, heat rejection, and crash protection; even “micro” units are large compared to a car powertrain.
• Regulation and risk: placing thousands of mobile reactors on public roads is incompatible with current nuclear safety regimes worldwide.

Microreactors are promising for remote sites and defense or space applications, but they are not a viable or licensable option for passenger cars.

Could a nuclear source trickle‑charge an EV battery?

In a thought experiment, a small continuous source could slowly add energy to a battery, extending range over time without plugging in. The challenge is obtaining enough continuous power to matter.

• A 100 W source (comparable to a single MMRTG’s electrical output) yields about 2.4 kWh per day—roughly 10–16 km of range/day for an efficient EV. Getting 500 W would meaningfully help, but requires multiple RTG‑class units and significant isotope mass.
• Even if technically packaged, real‑world road safety, licensing, supply scarcity (Pu‑238 production is tens to hundreds of grams per year), and costs would be prohibitive.

As an engineering curiosity, trickle‑charging works on paper. In the real world, the materials, safety, and regulatory barriers keep it on the drawing board.

Safety, supply, and policy barriers

Beyond the physics of power density, several nontechnical obstacles are decisive.

• Public safety and crashworthiness: protecting radioactive material in high‑speed collisions and fires is a formidable challenge.
• Material control and security: radioisotopes are tightly controlled to prevent theft or misuse; widespread deployment in consumer cars is incompatible with current safeguards.
• Waste and end‑of‑life handling: every vehicle would entail nuclear end‑of‑life logistics and liability.
• Supply constraints: isotopes like Pu‑238 are extremely scarce and prioritized for space missions; betavoltaic isotopes (e.g., Ni‑63, tritium) are also constrained and costly.
• Regulation: nuclear transport and use on public roads would trigger international and national rules that effectively preclude consumer deployment.

These barriers are not incremental; they are structural, making consumer nuclear‑powered cars impractical for the foreseeable future.

Where nuclear and cars do meet—indirectly

The practical intersection today is the grid. Nuclear plants produce low‑carbon electricity that can charge EVs, cutting tailpipe emissions without putting radioactive material onboard.

• Grid decarbonization: pairing EVs with nuclear, wind, and solar reduces lifecycle emissions compared with gasoline vehicles.
• Resilience: expanding nuclear generation can stabilize grids as EV adoption grows.
• Niche auxiliary roles: in the future, ultra‑low‑power nuclear cells may run sensors or security systems in vehicles where battery replacement is hard, but not the drivetrain.

This pathway leverages nuclear energy’s strengths—reliable baseload power—without the safety and regulatory complications of mobile nuclear sources.

About those splashy “nuclear battery” announcements

Since 2024, startups have publicized long‑life “nuclear batteries,” often using nickel‑63 or tritium in diamond semiconductor stacks. The headlines can be confusing without context.

• Demonstrated outputs are in the microwatt to milliwatt range, suitable for sensors, not motors.
• Claims of multi‑watt modules remain largely at the prototype or roadmap stage; as of 2025, no certified, commercially available, watt‑to‑kilowatt nuclear battery exists for automotive traction.
• Automotive safety certification and nuclear licensing are separate, rigorous hurdles that such devices have not crossed.

These technologies are interesting and may find real uses in IoT, space, and defense. They do not change the fundamental power gap for cars today.

Bottom line

A nuclear battery cannot practically power a car. Radioisotope and betavoltaic devices provide too little power, and compact reactors that could deliver enough are too heavy, complex, and tightly regulated for road use. The realistic role for nuclear in personal transport is indirect: supplying clean electricity to the grid that charges electric vehicles.

Summary

Passenger cars need tens of kilowatts of power; nuclear batteries deliver microwatts to hundreds of watts. Scaling radioisotope systems to car levels is infeasible due to power density, heat, cost, and materials scarcity, while compact fission reactors are too heavy and legally untenable for consumer vehicles. Nuclear energy’s best contribution to mobility is grid electricity for EVs, not on‑board propulsion.

Could nuclear batteries power cars?

Aside from low power Radio Thermal Generators, like on spacecraft, you can’t really make a compact nuclear reactor that would fit in a car. The smallest reactor designs around, like the KiloPower 10 kW reactor weights 1.5 tonnes, and only produces 10 kW, which is about a tenth the power requirement of a car motor.

Why don’t we use nuclear batteries?

The cost of producing nuclear batteries is impractical for certain applications. Radioisotopes can be rare and the technology necessary to effectively utilize them can be expensive.

Is a nuclear-powered car possible?

A nuclear-powered car is not feasible for direct use due to insurmountable technical challenges, primarily the excessive weight of the necessary radiation shielding, the extreme complexity of miniaturizing a safe and efficient reactor, and immense safety concerns regarding radiation and catastrophic accidents. However, nuclear power can be used indirectly to power cars by generating electricity in large, central plants, which is then used to charge electric vehicles (EVs). 
Challenges of a Direct Nuclear-Powered Car

• Excessive Weight and Size: A nuclear reactor requires heavy, dense shielding (like lead or concrete) to contain radiation, making the overall vehicle extremely heavy and impractical for mass production or even a single car. 
• Safety and Security: The risks of radiation exposure, potential nuclear leaks, and catastrophic outcomes in a car crash are too significant to overcome. Managing a small nuclear reactor’s complex reactivity and ensuring safety in traffic would be incredibly difficult. 
• Complexity and Cost: Miniaturizing a reactor for automotive use would be an extremely complex and expensive engineering feat, far exceeding the efficiency and cost-effectiveness of a central nuclear power plant. 
• Heat Management: A car-sized vehicle would struggle to dissipate the enormous amounts of waste heat generated by a nuclear reaction, lacking the extensive heat management systems of larger power plants. 
• Fuel and Waste: Obtaining and handling highly enriched nuclear fuel for a car, as well as the safe disposal of nuclear waste, presents further problems. 

Indirect Nuclear Power for Cars 

• Nuclear-Powered EV Charging: The most practical way to power a car with nuclear energy is through the electrical grid. Nuclear power plants generate electricity that can be used to charge the batteries of electric vehicles, offering a clean energy alternative.

Historical Context 

• The concept of a nuclear-powered car was explored in the 1950s by Ford with the Ford Nucleon concept. However, this was only a model, and the actual vehicle was never built due to the prohibitive technical, safety, and cost issues.

Why don’t we use nuclear power for cars?

Having radioactive material readily available is a security and public health concern and even uranium that’s not highly enriched could be used in a dirty bomb or other harmful radiological device. A nuclear-powered car would have to be immune from such tampering.