Nuclear energy powers about 9% of the world’s electricity, but its uses extend well beyond the grid. From diagnosing heart disease to keeping Mars rovers running, nuclear technology plays a role in medicine, food safety, agriculture, space exploration, and industrial manufacturing. Here’s how it’s being used right now.
Electricity Generation
The most visible use of nuclear energy is generating electricity. Globally, 416 nuclear power reactors operate across 31 countries, with a combined capacity of 376 gigawatts. The United States leads the world with 94 operating reactors, followed by France, China, Russia, and South Korea. Together, these five countries account for 71% of global nuclear generating capacity.
Nuclear power produces about 25% of all low-carbon electricity worldwide. Because reactors emit no greenhouse gases at the point of generation, many countries treat nuclear as a key part of their climate strategy. China alone has 28 reactors under construction, adding 30 gigawatts of new capacity. Russia has another 4 units in progress, and South Korea has 2.
Medical Imaging and Diagnosis
Hospitals rely on radioactive isotopes produced in nuclear reactors for millions of diagnostic scans every year. The workhorse of nuclear medicine is a tracer called technetium-99m, which is used in single-photon emission imaging (SPECT scans) of nearly every major organ system: the brain, heart, bones, lungs, kidneys, liver, thyroid, and spleen.
Different chemical forms of this tracer are tailored for specific jobs. Some are designed to map blood flow through the heart, helping doctors identify blocked coronary arteries or damage from a heart attack. Others track blood pooling in the gut to locate internal bleeding, image bone fractures and infections, assess kidney function, or locate the lymph nodes draining a tumor in breast cancer or melanoma patients. One variant specifically diagnoses a condition called Meckel’s diverticulum, an abnormal pouch in the small intestine. Another maps blood flow in the brain to pinpoint the area affected by a stroke.
Cancer Treatment
Beyond diagnosis, nuclear technology is used to destroy cancer cells directly. Radioactive iodine therapy exploits the thyroid gland’s natural tendency to absorb iodine. When a patient swallows a dose of radioactive iodine, the thyroid pulls it in, and the radiation destroys cancerous thyroid tissue while largely sparing the rest of the body.
For cancers that have spread to the bones, a treatment using radium-223 works on a similar principle. The radium integrates into newly forming bone, particularly within metastases, and emits short-range alpha particles that destroy nearby tumor cells without heavily damaging surrounding healthy tissue. Another targeted therapy uses lutetium-177 attached to a protein that binds to receptors on neuroendocrine tumors of the gastrointestinal tract and pancreas, delivering radiation directly to the cancer.
Food Safety and Shelf Life
Over 50 countries have authorized the use of ionizing radiation to treat roughly 50 different food products. Food irradiation kills harmful bacteria like Salmonella and E. coli, extends shelf life, and prevents sprouting in stored produce. Spices are the largest category of irradiated foods worldwide. Other common applications include preventing potatoes, onions, garlic, and ginger from sprouting during storage, killing parasites in fresh pork, and extending the shelf life of fresh fish, shellfish, and strawberries.
The radiation sources used for this process include cobalt-60, which produces gamma rays, and machine-generated electron beams and X-rays. The food never becomes radioactive. The process simply passes energy through the product, much like a microwave oven uses a different type of energy to heat food. Cobalt-60 has been the traditional workhorse, but electron beam technology is increasingly used as an alternative.
Pest Control in Agriculture
The sterile insect technique uses nuclear radiation to sterilize male insects, which are then released into the wild to mate with females. Because those matings produce no offspring, the pest population collapses over time without chemical pesticides.
This approach has been used to protect citrus orchards and other fresh fruit crops from the Mediterranean fruit fly, grapevines in Chile from the European grapevine moth, and apple orchards in New Zealand from the codling moth. Researchers have also developed effective sterilization doses for agricultural stink bugs that damage a wide range of crops. Unlike blanket insecticide spraying, the technique is highly targeted and leaves no chemical residue on food or in soil.
Space Exploration
Solar panels work well close to the Sun, but missions to the outer solar system or the surface of Mars need a power source that works in darkness and dust storms. That source is the radioisotope thermoelectric generator, or RTG, a device that converts the heat from decaying plutonium-238 into electricity.
NASA’s Perseverance rover, which landed on Mars in 2021, runs on one. So does the Curiosity rover, which has been exploring Gale Crater since 2012. New Horizons, the spacecraft that flew past Pluto in 2015 and later visited the distant object Arrokoth, carries a single RTG fueled by about 24 pounds of plutonium oxide. The Voyager 1 and Voyager 2 probes, launched in 1977, are still transmitting data from interstellar space using RTGs that originally produced about 158 watts each at launch and were still operating at around 225 watts of electrical output in late 2023. No other power source could have kept those spacecraft alive for nearly five decades.
Industrial Inspection
Manufacturers in the oil and gas, aerospace, automotive, and construction industries use nuclear radiation to inspect materials without cutting them open. This technique, called industrial radiography, works like a medical X-ray: radiation passes through a metal component, and the resulting image reveals internal cracks, corrosion, weld defects, or air pockets that could cause a failure.
Portable gamma radiography cameras are especially valuable for inspecting oil and gas pipelines in the field, where components can’t be brought to a lab. In aerospace, the same principle is used to check aircraft parts and engine components for hidden flaws. The technique catches problems that would be invisible to the naked eye, preventing catastrophic failures in high-stakes environments.
Hydrogen Production
Nuclear power plants generate large amounts of heat and electricity, both of which can be used to split water into hydrogen and oxygen through electrolysis. Hydrogen produced this way is sometimes called “pink hydrogen” to distinguish it from hydrogen made using fossil fuels (gray) or renewables (green). Because nuclear plants run around the clock regardless of weather, they can produce hydrogen continuously, making them a potentially reliable source of clean hydrogen fuel for heavy industry and transportation.