Nuclear Power: From bomb to energy

It remains one of the most ironic aspects of modern civilisation that humanity first split the atom to destroy cities, and only later learned to power them through the same process. The nuclear bomb came before the nuclear power plant, an inversion of what one might expect from scientific progress. 

Today, that paradox still lingers in numbers; according to the International Atomic Energy Agency, roughly 12,187 nuclear warheads exist globally, compared to only about 415 operational nuclear reactors. 

There are roughly 30 times more nuclear weapons on Earth right now than there are nuclear power plants. The same science that once defined annihilation now powers cities with some of the cleanest energy available.

Graphics: TBS

Nuclear fission, the splitting of heavy atoms to release enormous amounts of energy, was first identified in 1938. Scientists immediately recognised its dual nature; if controlled, it could generate electricity; uncontrolled, it could unleash devastation. 

World War II decided the direction. The Manhattan Project, launched in 1942, diverted global scientific effort towards building atomic weapons. Ironically, even as physicist Enrico Fermi achieved the first self-sustaining nuclear chain reaction in Chicago that same year, it was done to prove the bomb's feasibility, not to power homes. 

The devastation of Hiroshima and Nagasaki in 1945 triggered a moral reckoning. Scientists began advocating for peaceful uses of nuclear energy. In 1953, US President Dwight D Eisenhower's "Atoms for Peace" speech at the United Nations formally pivoted global attention towards civilian nuclear applications. 

By 1951, a reactor in Idaho produced the first usable nuclear electricity, just enough to light four bulbs. By 1954, the Soviet Union connected the first nuclear plant to a power grid. And by 1956, the UK's Calder Hall became the first commercial-scale plant. The shift had begun.

Today, the urgency of energy demand has brought nuclear power back into focus. According to the International Energy Agency, the world consumes approximately 30,000 terawatt-hours (TWh) of electricity annually, or about 82 TWh per day, with demand growing at roughly 3% each year. 

This surge is driven by electric vehicles, data centres, and artificial intelligence. Nuclear energy currently supplies 9% to 10% of global electricity, making it the second-largest source of low-carbon power after hydropower. 

Its appeal lies in its consistency; unlike solar or wind, nuclear plants provide uninterrupted baseload energy, quietly underpinning modern life without the volatility of weather-dependent sources.

Coal has long powered industrial growth, but at immense environmental cost. It is the largest contributor to global carbon emissions, releasing more CO₂ per unit of energy than any other fuel. Beyond climate change, coal plants emit sulfur dioxide, nitrogen oxides, and fine particulate matter — pollutants linked to acid rain, smog, and millions of premature deaths annually. 

To prevent failures like the one in Fukushima, Rooppur includes passive heat removal systems that can cool the reactor for up to 72 hours without electricity, relying on natural circulation and convection. It also uses hydro-accumulator tanks to inject cooling fluid automatically during pressure drops.

They also release heavy metals like mercury and arsenic, contaminating ecosystems, and produce vast quantities of toxic coal ash that often leak into groundwater. Nuclear power, by contrast, operates with virtually zero direct greenhouse gas emissions. 

The plumes rising from cooling towers are not smoke but water vapour. Its land footprint is minimal, and its waste is small in volume and strictly contained. In short, nuclear energy is not without risk, but compared to fossil fuels, it is markedly cleaner and more controlled.

The promise of nuclear energy, however, is overshadowed by two defining disasters that reshaped global perception and regulation. 

The Chernobyl disaster in 1986 remains the worst in history. 

During a late-night safety test, operators at Reactor No. 4 disabled critical safety systems and pushed the reactor into instability. 

A combination of human error and flawed reactor design triggered a catastrophic power surge, estimated to be 100 times the reactor's normal output. The result was a massive steam explosion that blew off the reactor's 1,000-tonne lid, followed by a second explosion that exposed the core. 

A graphite fire burned for nine days, releasing radioactive material across Europe. The human toll was both immediate and long-term. Two workers died instantly; 28 more succumbed to acute radiation sickness within weeks. Over 100,000 people were permanently displaced, and a 30-kilometre exclusion zone still surrounds the site.

The physical meltdown itself was equally dramatic. Temperatures soared beyond 2,865°C, melting uranium fuel into a lava-like substance known as corium, which burned through the reactor structure. The runaway sequence began with an uncontrolled power excursion, followed by flash boiling of cooling water, and a devastating zirconium-steam reaction that generated additional heat and hydrogen gas. 

This chain reaction created a molten mass that flowed through the reactor's base, eventually solidifying into formations such as the infamous "Elephant's Foot." The site was hastily sealed with a concrete sarcophagus in 1986, later reinforced in 2016 with a steel enclosure designed to last a century.

If Chernobyl was a failure of design and discipline, the Fukushima Daiichi disaster in 2011 was a failure against nature. Triggered by a magnitude 9.0 earthquake and a subsequent 14-metre tsunami, the plant initially shut down safely, with reactors automatically halting fission through a "scram" process. 

However, the tsunami overwhelmed defences built for much smaller waves, flooding backup generators and causing a total power loss, a "station blackout." Without electricity, cooling systems failed. Over the following days, three reactors, Units 1, 2, and 3, experienced meltdowns as water levels dropped and fuel rods overheated.

Hydrogen gas accumulated from high-temperature reactions and led to explosions that destroyed reactor buildings. While there were no direct deaths from radiation, the evacuation of 154,000 residents and the stress of displacement caused hundreds of indirect fatalities. 

The environmental impact included the release of radioactive isotopes such as iodine-131 and cesium-137 into the atmosphere and ocean. The cleanup remains ongoing and is expected to take 30 to 40 years, involving the removal of melted fuel debris and management of treated wastewater. 

Not all reactors shared the same fate: Units 4, 5, and 6 avoided meltdowns due to either the absence of fuel in the core or the survival of a single backup generator that allowed continued cooling.

Modern nuclear engineering has evolved directly from these failures. Bangladesh's Rooppur Nuclear Power Plant (RNPP) exemplifies this new generation of safety-focused design. 

Located in Ishwardi, Pabna, and built with Russian assistance at a cost of $12.65 billion, the plant marked a historic milestone on 28 April 2026, when it began loading 163 uranium fuel assemblies into Unit 1. 

This step officially brought Bangladesh into the nuclear era as the 33rd country globally, and the third in South Asia after India and Pakistan, to generate nuclear electricity.

The facility uses Generation III+ VVER-1200 reactors, which incorporate multiple layers of safety. Unlike Chernobyl's RBMK design, these reactors have a negative void coefficient, meaning the reaction naturally slows if cooling water is lost. 

The plant features a double containment structure, with an inner layer to contain radioactive material and an outer reinforced shell capable of withstanding magnitude 9 earthquakes, floods, and even aircraft impact. 

To address Fukushima-type failures, Rooppur includes passive heat removal systems that can cool the reactor for up to 72 hours without electricity, relying on natural circulation and convection. It also uses hydro-accumulator tanks to inject cooling fluid automatically during pressure drops.

Perhaps the most significant safeguard is the core catcher, a 200-tonne steel structure beneath the reactor designed to trap and cool molten fuel in the unlikely event of a meltdown. Diluting and solidifying the radioactive material, it prevents contamination of soil and groundwater. 

Once fully operational, the plant's two units will produce 2,400 MW, meeting 10% to 12% of Bangladesh's electricity demand. Unit 1 is expected to supply about 300 MW by August 2026, reaching full capacity by 2027, offering a stable baseload to ease grid shortages and reduce reliance on imported fossil fuels.

Globally, nuclear energy remains concentrated among a few nations. The US leads with around 94 reactors, generating about 18–20% of its electricity. China and France each operate 57 reactors, though France stands out by deriving 67% of its electricity from nuclear power, the highest share worldwide. 

Russia runs about 34 reactors, while South Korea operates 26, and Japan maintains over 30 operable units, many still offline following Fukushima. In total, nuclear reactors provide 370 to 376 gigawatts of capacity worldwide, contributing roughly a tenth of global electricity.

At the same time, the world is witnessing what many describe as a "nuclear renaissance". More than 60 reactors are currently under construction, with China accounting for over half. Emerging entrants such as Bangladesh, Egypt, and Türkiye are building their first plants, driven by rising demand and the need for low-carbon energy.

There is also redemption embedded in nuclear history. In the 1990s, the "Megatons to Megawatts" programme saw the US and Russia dismantle thousands of nuclear warheads and convert their enriched uranium into fuel for power plants. 

For two decades, roughly 1 in 10 lightbulbs in America was powered by a dismantled Russian nuclear bomb. It remains one of the clearest examples of turning instruments of destruction into tools of everyday life.

The paradox remains. Nuclear energy exists at the intersection of fear and necessity, capable of catastrophic failure, yet indispensable in a warming world. As global electricity demand surges and the pressure to decarbonise intensifies, the atom is once again being reimagined.