Uranium matters because it packs an extraordinary amount of energy into a tiny amount of material. A single uranium fuel pellet, roughly the size of a pencil eraser, produces as much energy as one ton of coal, 149 gallons of oil, or 17,000 cubic feet of natural gas. That energy density makes uranium the backbone of nuclear power, which currently supplies 9% of the world’s electricity. But uranium’s importance extends well beyond power plants, reaching into cancer treatment, space exploration, military technology, and the global push to cut carbon emissions.
How Uranium Produces Energy
Uranium’s usefulness starts at the atomic level. The nucleus of uranium-235 contains 92 protons and 143 neutrons in a somewhat unstable arrangement. When a stray neutron strikes that nucleus, it splits into two smaller parts, a process called fission. Each split releases a burst of heat along with two or three additional neutrons, which can then strike other uranium-235 nuclei and trigger more fission events. This cascade is a chain reaction, and controlling it is what a nuclear reactor does.
Inside a power plant, the heat from fission superheats water into steam, which spins turbines to generate electricity. The process uses no combustion and produces no smokestack emissions. A reactor can run continuously for 18 to 24 months on a single fuel load, making nuclear one of the most reliable sources of baseload power available.
A Low-Carbon Energy Source
One of uranium’s most significant roles today is helping reduce greenhouse gas emissions. Over its full lifecycle, including mining, fuel processing, plant construction, and waste management, nuclear energy produces between 5.4 and 122 grams of CO₂ equivalent per kilowatt-hour. Coal, by comparison, emits roughly 1,001 grams per kilowatt-hour. Even at the upper end of estimates, nuclear power generates a fraction of the carbon that fossil fuels do, putting it in the same range as wind and solar.
Because nuclear plants generate power around the clock regardless of weather, they complement intermittent renewables like wind and solar. Countries trying to decarbonize their electrical grids often keep nuclear in the mix precisely because it can deliver large volumes of clean electricity on demand, day or night.
Who Produces It and Why That Matters
Uranium is a strategic resource, and its production is concentrated in a handful of countries. In 2022, 17 nations mined uranium, producing a combined 49,490 metric tons. By 2023, that figure rose 10% to 54,345 metric tons. Kazakhstan dominates the market, accounting for 43% of global output. Its production alone exceeds the combined totals of the next four largest producers: Canada (15%), Namibia (12%), Australia (9%), and Uzbekistan (7%). Just six countries supply 90% of the world’s uranium.
This concentration creates supply chain risks. Countries that rely heavily on nuclear power but lack domestic uranium deposits depend on stable trade relationships with producing nations. Russia, the sixth-largest producer at 5% of global output, also controls a significant share of uranium enrichment capacity, which adds a geopolitical dimension to energy security planning. For many governments, securing reliable uranium supplies is as much a foreign policy concern as an energy one.
Cancer Treatment With Uranium Isotopes
Uranium’s medical applications are less well known but increasingly important. Researchers have developed a method called targeted alpha therapy that uses uranium-230, a specific isotope produced by bombarding natural thorium with high-energy protons. As uranium-230 decays, it produces thorium-226. Both isotopes emit alpha particles, which are far more destructive to cells than the beta particles used in many conventional radiation treatments.
What makes alpha particles especially useful for cancer is their short range inside the body. They deliver intense energy over just a few cell widths, destroying tumor cells while doing much less damage to surrounding healthy tissue. This precision means alpha-emitting treatments can potentially target cancers that have already spread or metastasized, situations where broader radiation approaches risk too much collateral harm. These isotopes are attached to biologically compatible molecules to create radiopharmaceuticals that can be injected and carried directly to the tumor site.
Powering Deep Space Missions
Uranium’s role in space exploration is indirect but essential. Plutonium-238, the isotope that powers deep space probes and planetary rovers, is produced in nuclear reactors fueled by uranium. Devices called radioisotope thermoelectric generators (RTGs) convert the heat from plutonium-238’s natural radioactive decay into electricity using solid-state components with no moving parts. The temperature difference between the hot fuel and the cold vacuum of space drives the process.
RTGs have powered some of NASA’s most iconic missions. The Cassini spacecraft carried three RTGs during its 13-year exploration of Saturn. The Curiosity rover on Mars runs on a similar system. New Horizons, which flew past Pluto in 2015 and continues exploring the outer solar system, uses a spare RTG originally built for Cassini. Solar panels become impractical far from the Sun, so without the plutonium-238 supply chain that begins with uranium, exploration of the outer planets and deep space would be effectively impossible.
Military and Industrial Uses of Depleted Uranium
After the fissile uranium-235 is extracted for reactor fuel, the remaining material is called depleted uranium. It retains uranium’s extreme density (about 1.7 times denser than lead) while being far less radioactive than enriched uranium. That density makes it valuable in several specialized applications.
In military technology, depleted uranium is used in armor-piercing ammunition and in the armor plates of heavy tanks. The rounds penetrate armored targets because of their high kinetic energy, and uranium’s pyrophoric properties (it ignites on impact at high speeds) add to their effectiveness. Outside the military, depleted uranium has served as counterbalance weight in aircraft and missiles, radiation shielding in medical radiotherapy equipment, and ballast in sailboat keels and forklifts. Wherever you need maximum weight in minimum space, depleted uranium is a candidate material.
Next-Generation Reactor Designs
New reactor concepts are changing how efficiently uranium is used. Small modular reactors (SMRs), like the NuScale Power Module with a thermal capacity of 160 megawatts, are designed for two-year operating cycles and can be factory-built in standardized units. Their smaller size makes them suitable for remote locations, industrial sites, or grids that don’t need a full-scale 1,000-megawatt plant.
Researchers are also exploring thorium as a complementary fuel to uranium. In some reactor designs, thorium-based fuel achieves a higher conversion ratio (0.765 compared to 0.574 for standard uranium fuel), meaning it converts more of its starting material into usable fissile fuel during operation. Thorium cycles also generate uranium-233 during burnup, which supports longer fuel use before replacement is needed. While thorium won’t replace uranium, pairing the two fuels could stretch global nuclear fuel supplies and reduce waste volumes over time.