From horror to hope:  

This year marks the 80th anniversary of the atomic bombings of Hiroshima and Nagasaki, the first, and thankfully last, time atomic weapons were used in warfare. With nuclear energy now set to play a key peaceful role in reducing carbon emissions, we look at how this energy source transitioned from destruction to a force for good.  

That fateful day 

On the morning of 6 August 1945, the American plane Enola Gay, named after the mother of its pilot Colonel Paul Tibbets, flew over the sky of the Japanese city of Hiroshima. At 8.15am the crew released the device codenamed Little Boy, which contained 141 lb of uranium-235 and, over the next 44 seconds, fell 29,000 feet before detonating above the city, releasing a blast equivalent to 14,000 tonnes of TNT. Up to 80,000 people were killed in the blast, while up to half of the city’s population of 340,000 would have died by the end of the year from its after affects.   

Colonel Tibbets commented from the plane: “It was hard to believe what we saw. The whole thing was tremendous and awe-inspiring. The men aboard with me gasped 'My God’.” Yoshito Matsushige, who managed to get pictures of the aftermath, said: “It was really a terrible scene. It was just like something out of hell.” US President Harry Truman warned the Japanese: “If they do not now accept our terms, they may expect a rain of ruin from the air, the like of which has never been seen on this earth.” Three days later the city of Nagasaki suffered a similar fate when the weapon Fat Man was dropped on it, while Japanese woes were compounded by the Soviet invasion of occupied-China. On 15 August, Japan formally surrendered.  

While the war was over, it was clear that the world was moving into the Atomic Age with the advent of this weapon of unimaginable destruction, which was still in its infancy. Yet despite fears and close calls that continue to this day, there has never been another nuclear weapon used in war. Following its development for destruction, scientists soon began exploring the possibilities for peaceful use of nuclear to create energy. This has not been without danger or incident, and there have been notable crises throughout the decades, with the likes Chernobyl, Three Mile Island and Fukashima giving the industry a level of infamy. Yet, as the world pushes to reduce its carbon emissions drastically and achieve ambitious net zero targets, Member News speaks with industry expert Will Davis about the leading role nuclear has to play.   

Understanding nuclear  

“Nuclear is anything taking place to do with the atom, or that level of matter,” explains Will. “Fission splits that nucleus; fusion combines nuclei. Both produce energy depending on what you split and fuse to get energy out.”  

A pivotal moment in the understanding of nuclear physics arrived after Albert Einstein published his Special Theory of Relativity in 1905, giving us the world’s most famous equation: E = mc2. That enabled scientists to understand how much energy was in an atom, and that atoms could be fused to create enormous amounts of heat.  

“That heat could be used to create steam and drive turbines, just like what was being done with coal and oil at that point. It could also be unleashed as a weapon.”  

While there was the basic understanding of nuclear physics, the Second World War provided the impetus to fund scientists to explore this field fully. The Americans and Germans both understood the possible uses of nuclear, though it was the USA which continued to invest heavily in its Manhattan Project that would ultimately wield the atomic bomb, The Third Reich scaled down its research and actually saw many of its eminent scientists seek refuge across the Atlantic.   

“Plutonium is created from uranium, which is done in a reactor through a process called ‘breeding’. Uranium is the heaviest naturally occurring element, which is fairly common, and through fission some of it is converted into plutonium, an artificial element.”  

The first reactor was the Chicago Pile, which made plutonium but not for producing energy. The air-cooled graphite moderators used there would be the same type that the UK nuclear industry would be built around, including the Windscale Piles in Cumberland. The fire there in 1957 and the resulting contamination – the worst nuclear accident in UK history – would lay the foundation for the strict regulations that govern the industry in Britain today.  Safety improvements included adding a filter atop the piles to reduce contamination, and then the next generation of stations using stainless steel pins to allow much higher temperatures to create super-heated steam to power the turbines. 

Creating energy, not weaponry  

“People knew that if this power could be harnessed in the right way it could be beneficial, but a weapon does not have to be controlled as tightly, just detonated. Back in 1945 they did not have computers to run these huge calculations and understand all the permutations.   

“While the fundamental principles are the same – using a reaction to create heat and energy – there are numerous structural challenges involved in creating a power station. This is where science meets the reality of the world and there are engineering limitations. It’s not the science that is the challenge today, more the engineering aspects.”  

Other countries chose to pursue water-moderated reactors rather than graphite, which became the most common. Canada created a design using heavy water and became a leading developer of these new reactors as an outlier in developing the technology for civilian rather than military use, and also to power submarines.  

“This technology has helped us to develop small modular reactors, which could in principle operate for decades without refuelling, although none of the current designs take that approach due to the high costs and increased proliferation risks of using the same highly enriched uranium which is used in submarine reactors. The benefit of a fuelled-for-life reactor is that they never need to be opened.   

“Reactors can run for a long time. A significant challenge with older nuclear power stations is that some components, such as electronics, need to be replaced for maintenance, and some may become more difficult to obtain. The periodic safety review programme in the UK requires a thorough review every ten years, or more frequently where necessary.”  

Achieving green goals  

The UK has a legal obligation to produce 95 per cent of its power from green sources by 2030, and reduce its carbon emissions to net zero by 2050. Other countries have similarly ambitious targets in the rush to end climate change being caused by greenhouse gas emissions.  

“When you burn coal or oil, the amount of energy per chemical reaction is far smaller than is released per nuclear fission reaction; therefore, you need a far smaller amount of uranium. Oil and coal would likely have three to five decades left to provide our power, while for uranium, even with increased generation to cover the removal of fossil fuels, there would be enough for thousands if not millions of years. It’s relatively abundant and in places that are politically stable too, which is a current worry with oil and gas.”  

The UK now produces around 41 per cent of its energy from renewable sources including wind, solar and hydroelectric, with many seeing these sources as preferable to further investment in nuclear.  

“As great as renewables are, we do not have security of supply with them as they’re entirely weather dependent. Nuclear can give us that security; we already have the source of the power and control of the technology.”  

As nuclear does not emit the damaging greenhouse gases that fossil fuels do, it is seen as an increasingly attractive option to help reach those ambitious carbon-reduction goals.  

Ensuring safety   

“Nuclear fission is self-sustaining; you split the atom, two or three neutrons are released, some are absorbed by control rods and others hit another uranium atom. This chain reaction is closely monitored and controlled to maintain a steady state equilibrium which is referred to as “criticality” – there is just sufficient critical number of neutrons to maintain a steady reaction. Power stations control these reactions to sustain a constant level and not allow a runaway chain reaction. Managing that is now well understood.  

“The problem historically has been a lack of safety culture; at both Three Mile Island and Chernobyl, safety was not at the forefront of decision making although, just like with the Windscale Piles, there was an overhaul of safety procedures after them. The Fukashima accident was not caused by a lack of safety culture, but because it was built in a time when a combination of major events was not accounted for in the safety design. Many hazards were accounted for, such as earthquakes, floods, plane crashes, and more; just not in combination.   

“Since then, every nuclear station is checked against a wide range of ‘what if?’ scenarios and event combinations that may mean the reactor cannot be cooled.  

“Is nuclear safe enough now? In my opinion yes, it’s never been safer, even with changing threats like security issues.”  

Powering the future  

Nuclear provides about a tenth of world power today; it’s higher in the UK at 15 per cent, but that is half what it was at its peak in 1997. Over the last three decades electricity demand has surged, while many ageing nuclear facilities that have been shut down have not been replaced.  

“Once nuclear plants are up and running, they just operate at a constant level; in the UK, we don’t need to turn them up or down based on demand.  

“I want to see nuclear in the right role. We need energy that’s available; has security of supply; does not emit greenhouse gasses; and is relatively cheap. With nuclear, you can depend on the price as building the plant is almost the whole cost. It will just run, it does not change with weather, and is not dependent on unstable and potentially hostile parts of the world.   

“It needs to be safe, and we have that with nuclear too, without being blind to further safety improvements that we can continue to make. We need a mix, so that we can work towards turning off the oil and gas for good.”  

It has been eight decades since the world was given its first horrific glimpse into the power of nuclear. Since then, society and technology have come a long way, with a global focus now more closely linked to cooperation to solve problems rather than conflict, despite the persistence of war. While nuclear weapons remain stockpiled and disarmament seems unlikely, governments focus on how nuclear can be used to help achieve a peaceful future without carbon emissions rather than how many Megatons can be achieved in the next weapon. It may have started as a horrifying weapon, but, today, nuclear is giving us hope for a greener future.