How Much Uranium Would It Take to Power a Car?

Only a few grams of fissile uranium-235 could theoretically supply the lifetime electricity for a typical electric car; in practical reactor terms, about 0.1 kilograms of standard reactor fuel (and roughly 1 kilogram of mined natural uranium) would deliver the same. This article explains the math, the assumptions, and why “nuclear cars” aren’t a real-world proposition—even if the fuel quantity sounds astonishingly small.

The core math behind the headline

Assumptions and constants used in the estimates

To estimate how much uranium would power a car, we first need reasonable energy-use assumptions for an electric vehicle and well-established nuclear energy values. The figures below reflect typical, modern values used by engineers and energy analysts.

• EV energy consumption: 0.15–0.20 kWh per km; we’ll use 0.18 kWh/km (about 290 Wh/mile) as a midrange figure.
• Driving distance: 15,000 km per year; 200,000 km over a vehicle lifetime is a common benchmark.
• Fission energy of U‑235: ~8×10^13 joules per kg (about 22,000,000 kWh thermal if fully fissioned).
• Thermal-to-electric conversion: ~33% for a compact steam cycle (conservative, grid-scale reactors today are roughly one-third efficient).
• So, 1 kg of fully fissioned U‑235 yields about 7,300,000–7,500,000 kWh of electricity.
• Typical modern light-water reactor (LWR) burnup: ~45–60 GWd/t heavy metal; we’ll use 50 GWd/t as a midrange, which corresponds to roughly 400,000 kWh of electricity per kilogram of uranium fuel (heavy metal) in the core.
• Enrichment feed ratio: To make ~4.5% enriched fuel with 0.25% tails, you need about 9.2 kg of natural uranium feed for each kilogram of enriched product.

These inputs let us calculate uranium needs two ways: a theoretical “pure U‑235” minimum and a practical “real fuel in a typical reactor” figure.

Results at a glance

Here are the key takeaways, turned into everyday units.

• Per 100 km driven: about 2.5 mg of U‑235 (if fully fissioned) or ~45 mg of reactor uranium fuel (heavy metal) at typical burnup.
• Per year (15,000 km): about 0.35–0.40 g of U‑235, or roughly 6–7 g of reactor uranium fuel; that fuel would require about 60–65 g of mined natural uranium feed (after accounting for enrichment tails).
• Over 200,000 km (vehicle lifetime): roughly 4.5–5 g of U‑235, or about 90–100 g of reactor uranium fuel; natural uranium feed would be around 0.8–0.95 kg.
• Energy equivalence: 36,000 kWh (a typical EV’s lifetime electricity for 200,000 km at 0.18 kWh/km) equals about 1,070 “gallons of gasoline equivalent” by energy content—but an EV uses that electricity far more efficiently than an internal-combustion engine uses gasoline.

The grams-sized numbers are real and stem from fission’s immense energy density; the practical fuel requirement is still small, measuring in tens of grams of uranium over a full vehicle lifetime.

How the calculation works

The steps below show how the numbers are obtained, from EV energy needs to uranium mass.

1. Vehicle electricity demand: At 0.18 kWh/km, 100 km needs 18 kWh; 15,000 km/year needs 2,700 kWh; 200,000 km needs 36,000 kWh.
2. U‑235 “theoretical minimum”: With ~7.3–7.5 million kWh of electricity per kg of fully fissioned U‑235, the mass needed is electricity required divided by that figure. For 36,000 kWh: 36,000 / 7,400,000 ≈ 0.0049 kg ≈ 4.9 g of U‑235.
3. Practical reactor fuel (LWR burnup): Using ~400,000 kWh of electricity per kg of uranium fuel (heavy metal), the same 36,000 kWh requires 36,000 / 400,000 ≈ 0.09 kg ≈ 90 g of fuel.
4. Natural uranium feed: To produce enriched fuel, you need more mined natural uranium. With a typical feed-to-product ratio around 9.2 (for ~4.5% enrichment and 0.25% tails), 0.09–0.10 kg of fuel corresponds to roughly 0.8–0.95 kg of natural uranium.

The gap between the “pure U‑235” minimum and the “reactor fuel” figure reflects real-world limits: not all heavy metal in fuel fissions, some energy is lost in conversion, and enrichment leaves unused uranium in the tails.

Could a car actually carry that uranium?

Despite the tiny mass of fuel, a fission system suitable for a car would be anything but tiny. The challenge isn’t fuel quantity—it’s everything else a safe, controllable reactor needs.

• Shielding: Fission produces intense neutron and gamma radiation. Adequate shielding (e.g., borated materials for neutrons and dense metals for gammas) would weigh tons—far beyond passenger-car tolerances.
• Heat rejection: Even a compact reactor would generate steady thermal power requiring large, continuous cooling—difficult in a vehicle that spends much of its life parked or idling.
• Power dynamics: Cars need rapid power changes; reactors prefer stable operation. Bridging the gap adds complexity (buffers, batteries, turbines) and weight.
• Safety and regulation: Road crashes, maintenance, and end-of-life handling would pose unacceptable nuclear safety and security risks.
• Existing precedents: Radioisotope thermoelectric generators (RTGs) used in space produce only hundreds of watts—far short of the tens to hundreds of kilowatts a car demands.

Bottom line: the “nuclear car” is a thought experiment. In practice, uranium’s role is to generate grid electricity in secure plants that charge EVs, not to ride along with them.

What about microreactors or advanced concepts?

Microreactors now under development aim to deliver 1–20 MW of electric power for remote bases, industrial sites, or microgrids. Even these designs require substantial shielding, safety systems, and professional operation. While mobile demonstrations exist in military or industrial contexts, none are anywhere close to being safe, light, or simple enough for consumer vehicles. The realistic near-term interface between nuclear and cars is the grid: nuclear plants providing dependable, low-carbon electricity for EV charging.

The bigger picture: uranium demand per driver

Scaled to an individual, the uranium demand implied by these calculations is surprisingly small. A typical driver covering 15,000 km per year in an EV would consume electricity equivalent to about 2,700 kWh. That corresponds to roughly 0.35–0.40 grams of fully fissioned U‑235, or about 6–7 grams of uranium fuel in a modern reactor—requiring on the order of 60 grams of mined natural uranium feed after accounting for enrichment. Multiply by millions of drivers, and you see why nuclear power plants can, in principle, support large EV fleets without astronomical fuel needs.

Summary

In energy terms, uranium is extraordinarily dense. A typical electric car could be powered for 200,000 km by about 5 grams of fissile U‑235 in theory, or by roughly 90–100 grams of standard reactor uranium fuel in practice, which translates to around 0.8–0.95 kg of mined natural uranium after enrichment. However, the idea of a “uranium-fueled car” is impractical and unsafe: the reactor systems required would be massive and heavily shielded. The practical path is indirect—use uranium in secure plants to make electricity, and let EVs sip that power efficiently from the grid.

How much uranium is needed to power a car?

Just 1 gram of uranium-235 can generate enough energy to power a car thousands of miles. Compared to gasoline, uranium has an energetic power millions of times larger.

Can uranium be used for power?

In a nuclear reactor the uranium fuel is assembled in such a way that a controlled fission chain reaction can be achieved. The heat created by splitting the U-235 atoms is then used to make steam which spins a turbine to drive a generator, producing electricity.

Why don’t we use uranium as fuel?

The uranium oxide product of a uranium mill is not directly usable as fuel for a nuclear reactor – additional processing is required. Only 0.7% of natural uranium is ‘fissile’, or capable of undergoing fission, the process by which energy is produced in a nuclear reactor.

What can 1 kg of uranium do?

One kilogram of uranium-235 can theoretically produce about 20 terajoules of energy (2×1013 joules), assuming complete fission; as much energy as 1.5 million kilograms (1,500 tonnes) of coal.