60 Fun Facts About Nuclear Power

Roughly what share of the world's electricity did nuclear power plants supply in 2023?

That made nuclear the second-largest low-carbon power source after hydroelectricity, and there were 416 civilian reactors running worldwide as of late 2025.

Which country generates the highest percentage of its electricity from nuclear reactors?

France built 25 plants in 15 years after the 1970s energy shocks and hit 71% nuclear electricity by 2019.

Which country has the largest nuclear reactor fleet and produces the most nuclear electricity?

Its reactors generate almost 800 TWh a year at an average capacity factor of 92%, yet that is only about 19% of the electricity Americans consume.

To what level of uranium-235 is fuel typically enriched for civilian light water reactors?

Weapons need far higher enrichment; Shippingport's first core, taken from a cancelled aircraft carrier, used 93% seed fuel.

Which NASA probe is the textbook example of a spacecraft powered by a radioisotope thermoelectric generator?

Radioisotope thermoelectric generators produce only a few kilowatts but keep working for decades where sunlight is too weak for solar panels.

What was the first artificial nuclear reactor, which went critical on 2 December 1942?

It was built under the west stands of a football stadium, and Robert Crease called it and its predecessors the largest unbonded masonry structures since the pyramids.

Which physicist led the experiment that produced the first self-sustaining nuclear chain reaction in 1942?

He had won the 1938 Nobel Prize in Physics and emigrated to America shortly afterwards.

The first artificial reactor was assembled under which University of Chicago sports venue?

The stands were demolished in 1957; the site is now a National Historic Landmark marked by a memorial quadrangle.

What did the team drink from paper cups to celebrate the first controlled chain reaction?

Eugene Wigner had brought the bottle along; the scientists signed its straw wrapper afterwards.

Which Hungarian scientist first hypothesized the nuclear chain reaction, on 12 September 1933?

He later drafted the letter to President Roosevelt that Einstein signed, prompting US government fission research.

Which graphite impurity had misled German scientists into thinking it was unusable as a moderator?

The Germans failed to account for boron and cadmium contamination, so their test wrongly rejected graphite.

Near which Idaho town did EBR-I first generate electricity from a nuclear reactor on 20 December 1951?

That first run produced only about 100 kW, but the reactor soon powered its own building and the whole town.

How many 200-watt bulbs did EBR-I light in the first demonstration of nuclear electricity, in December 1951?

EBR-I was also the world's first breeder reactor and ran research until 1964.

Which US president delivered the 'Atoms for Peace' speech at the United Nations in 1953?

The speech pushed for rapid development of civilian uses of nuclear power at the height of the Cold War.

Which plant became the world's first nuclear power station to feed electricity to a grid, in June 1954?

Its tiny reactor produced only about 5 MW; the plant kept running until 2002 and its technology fed into much larger Soviet reactors.

What did the letters AM in the name of Obninsk's AM-1 reactor stand for in Russian?

Obninsk sits about 110 km southwest of Moscow and stayed the USSR's only power reactor until the Siberian station opened.

The world's first commercial nuclear power station, Calder Hall, joined the grid in 1956 in which country?

Calder Hall stood at Windscale, the same site that suffered a serious reactor fire the following year.

What was the name of the world's first nuclear-powered submarine, put to sea in January 1954?

In August 1958 she became the first submarine to make a submerged transit of the North Pole; today she is a museum ship in Groton, Connecticut.

What feat did the first nuclear submarine accomplish on 3 August 1958?

Nuclear propulsion let her stay submerged far longer than diesel-electric boats, unlocking routes under the Arctic ice.

Which 1970s event pushed oil-dependent countries such as Japan to invest heavily in nuclear power?

Countries that had burned oil for electricity suddenly had a strong reason to build reactors instead.

During the 1980s, how often on average did a new nuclear reactor start up somewhere in the world?

Global installed capacity reached 300 GW by 1990, three times the level of the late 1970s.

Which major economy voted against nuclear power in a 1987 referendum and phased it out completely by 1990?

The vote came the year after Chernobyl; Italy still has no operating nuclear stations.

After the 2011 Fukushima accident, which country approved plans to close all of its reactors by 2022?

A decade later Germany was restarting coal plants to replace lost Russian gas even as it finished the shutdown.

Which type of Soviet-designed reactor was involved in the 1986 Chernobyl disaster?

The RBMK design's positive void coefficient meant that steam bubbles in the coolant increased reactivity instead of damping it.

What was the name of the city near the Chernobyl plant that was abandoned after the 1986 explosion?

Its residents were not warned during the night of the accident; a 10 km exclusion zone was declared 36 hours later and around 49,000 people were moved out.

Radiation detected in which country on 28 April 1986 forced the USSR to publicly acknowledge Chernobyl?

Alarms went off at the Forsmark nuclear plant, more than 1,000 km from Chernobyl, and workers traced the source elsewhere.

Which neutron-absorbing fission by-product built up in the Chernobyl reactor as power was reduced?

The phenomenon is called reactor poisoning; in steady operation the isotope is burned off as fast as it forms.

Which purpose-built city replaced the abandoned town beside the Chernobyl plant?

It was built across the Dnieper marshes with a direct rail link to the plant.

What structure was completed in December 1986 to contain the wrecked Chernobyl reactor 4?

A far larger arch, the New Safe Confinement, was slid over the old sarcophagus in 2016–2018 to allow the debris to be removed.

Which international body was created after Chernobyl to promote safety awareness among nuclear plant crews?

WANO links every commercial operator worldwide; the IAEA, by contrast, dates from 1957.

The Three Mile Island plant sits on which river near Harrisburg, Pennsylvania?

The partial meltdown of Unit 2 began at 4:00 a.m. on 28 March 1979.

What component stuck open at Three Mile Island in 1979, letting coolant escape from the primary loop?

The Kemeny Commission found the same Babcock & Wilcox valve had failed on 11 earlier occasions, nine of them in the open position.

On the seven-point International Nuclear Event Scale, how was Three Mile Island rated?

Only two civilian power accidents, Chernobyl and Fukushima, have reached the top rating of 7.

Three Mile Island commission chair John Kemeny was president of which college?

President Carter, who had specialized in nuclear power in the Navy, created the commission in April 1979.

Which company struck a deal to have Three Mile Island Unit 1 restarted to power its data centers?

Unit 1 had run from 1985 until 2019, when it was retired for operating losses; the return is expected in 2027 or 2028.

Which utility owned and operated the Fukushima Daiichi plant at the time of the 2011 accident?

The same utility owns Kashiwazaki-Kariwa, the largest nuclear station in the world by net electrical rating.

Roughly how high was the largest tsunami wave to overtop the Fukushima Daiichi seawall in 2011?

The plant's ground level was only 10 metres above sea level, so the wave flooded the emergency generators.

Which Fukushima Daiichi reactors were operating when the Tōhoku earthquake struck on 11 March 2011?

All three shut down automatically on detecting the quake; it was the loss of cooling power after the tsunami that led to their meltdowns.

Which Japanese prime minister turned increasingly anti-nuclear after the 2011 Fukushima accident?

A parliamentary panel later criticized his office for possible excess meddling in the crisis's early stage.

Which two 1957 events were the first major nuclear accidents in history?

Kyshtym in the Soviet Union remains the only accident ever classified at INES Level 6.

The 1957 Kyshtym disaster took place at which secret Soviet plutonium plant?

The closed city was not on maps, so the disaster was named after Kyshtym, the nearest known town.

What was destroyed for about a month across 500 km² of English countryside after the 1957 Windscale fire?

Nobody was evacuated; the worry was iodine-131 contamination of dairy from local farms.

The SL-1 reactor, site of the first major US reactor accident in 1961, was run by which service?

An uncontrolled chain reaction caused a steam explosion and meltdown that killed the crew of three at what is now Idaho National Laboratory.

What is the concentrated uranium ore product known as yellowcake?

Yellowcake is made for transport; the uranium is later enriched and converted into ceramic UO2 fuel pellets.

Roughly what fraction of natural uranium is the fissile isotope uranium-235?

Some reactor designs can burn natural uranium, but the common light water reactor needs it enriched first.

Which three countries were the top uranium producers in 2022, with 69% of world output?

Uranium is roughly as common in the crust as tin, and about 40 times more common than silver.

Which element, 3.5 times more common than uranium, is central to the third stage of India's nuclear programme?

India has abundant reserves of it but little uranium, which shaped its three-stage plan.

Which country built Onkalo, the world's first deep repository for spent nuclear fuel?

Its name means 'small cave' or 'cavity'; the tunnels are cut into granite bedrock next to the Olkiluoto plant.

Which desert nuclear plant, cooled with treated sewage, is the world's only large one not sited near a body of water?

It buys wastewater from Phoenix-area towns and generates the second-most electricity of any US plant.

Which plant is the largest nuclear generating station in the world by net electrical power rating?

An earthquake with an epicenter only 19 km away shook it in July 2007.

Europe's largest nuclear power plant, seized by Russian forces on 4 March 2022, is in which country?

Zaporizhzhia has six VVER-1000 reactors near Enerhodar on the Kakhovka Reservoir.

Barakah, the first commercial nuclear station in its region, is in which country?

A KEPCO-led consortium won the $20 billion contract for its APR-1400 reactors in 2009.

The name of ITER, the giant fusion experiment at Cadarache, also means what in Latin?

Tokamak assembly began in 2020; a 2024 schedule revision set the start of research operations for 2034.

What is MOX fuel, produced by reprocessing plants such as La Hague?

La Hague has operated commercially since 1976 and handled about half the world's reprocessing as of 2010; the US does not reprocess at all.

Where were the early-1970s protests that launched the West German anti-nuclear movement?

The site on the Upper Rhine was never built; the movement it started eventually won a national phase-out.

Which French breeder reactor was powered down in 2009 after 36 years of operation?

Breeders convert non-fissile material into fuel, but cheap uranium has kept them uneconomic.

Roughly how many civilian fission reactors were operating worldwide as of November 2024?

Together they had a capacity of 374 gigawatts, with 66 more under construction, mostly generation III designs in Asia.

Which energy source has a lower historical death rate per unit of energy than nuclear?

Nuclear's rate is about 0.03 deaths per terawatt-hour; coal, oil, gas and hydro are all far deadlier once air pollution and accidents are counted.

Approximately how much uranium is dissolved in the world's seawater at any time?

It sits at only about 3 micrograms per litre, but a 2014 study suggested large-scale extraction could be economically competitive.

At which New York plant did a maintenance worker deliberately start a fire in 1971?

The damage ran to $5-10 million and remains the standard example of the insider-sabotage risk to nuclear sites.