Category: IAEA

Affum’s love for science began early. “I was fascinated by reactions — how combining substances could create new colours, even explosions,” she said. Excelling in math and chemistry, she studied chemical engineering, inspired by an aunt who was the family’s first physicist. “She showed me science wasn’t just a career; it was a way to solve problems,” Affum said.

After completing her bachelor’s degree, she was assigned to the Ghana Atomic Energy Commission (GAEC) for her mandatory national service. There, she became interested in air pollution monitoring and pursued further studies (MPhil) at the University of Ghana. “That was my turning point,” she recalled. “I realized engineering could directly improve lives.” Her research applied nuclear activation analysis to characterize established biomarkers of exposure to heavy metals from air pollution. Following on from this research, she joined GAEC’s radiotracer laboratory, collaborating closely with seasoned industrial experts in advancing radiotracer applications in Ghanaian industries.

Early on, scepticism loomed. Affum said that people were worried, asking her if she would find a job as a woman in engineering. But mentors like Professor Francis Allotey, a mathematician and nuclear physicist at GAEC, pushed her forward. “He was relentless — encouraging me to publish, speak at conferences, and mentor other women,” she said. Only two women worked in her centre at GAEC, but Affum thrived. Her parents had always encouraged her curiosity — her father through storytelling, and her mother through unwavering support. She blended her father’s journalistic ethos with scientific rigor. “He taught me to communicate complex ideas simply. Science must serve the public,” Affum said. “And my mum was my biggest fan!”

Joining the IAEA was never part of the plan. “I thought it was out of reach,” she said. But one of her international mentors, Professor Jovan Thereska, urged her to apply. “I doubted my qualifications, but he saw my potential.” In 2022, she took up a post as an IAEA industrial technologist. She uses radiotracer technology and NDT to help process industries  track how substances move through industrial systems — such as pipelines or reactors — and to identify defects in infrastructure. This work also supports disaster preparedness by ensuring critical systems function safely.

Her proudest achievement? Launching the IAEA’s Non-Destructive Testing Centre in Seibersdorf, Austria, in 2024. “After years of planning post-Fukushima, we now have a hub to train countries in NDT emergency response,” she said. The Centre equips countries — especially those prone to natural disasters — with cutting-edge tools to inspect critical civil infrastructure accurately and safely. “It’s about saving lives before crises strike,” Affum said.

Affum actively mentors young women through Women in Nuclear Ghana, emphasizing early exposure to math and science. “Many girls think STEM is ‘too hard,’ but it’s about passion, not innate genius,” she said. Affum challenges misconceptions about radiation head-on: “Yes, it can be harmful if misused, but its benefits — in cancer treatment, agriculture and industry — are transformative.”

Outside work, Affum and her husband mentor underprivileged youth in Ghana. “If I weren’t a scientist, I’d be a social worker,” she said. “Empowering people is my purpose.”

Her advice to young scientists? “Jump at opportunities, even if you feel unready. And remember science isn’t that difficult — it’s just a puzzle waiting for your unique solution.”

The IAEA is committed to gender equality and to supporting the ability of all individuals, regardless of gender, to equally contribute to and benefit from its programmes and activities. 

The IAEA’s Marie Sklodowska-Curie Fellowship Programme supports the next generation of women nuclear professionals by offering scholarships for master’s degree in nuclear-related fields, and the Lise Meitner Programme offers early- and mid-career women multi-week training visits to nuclear facilities.  

Read more about the IAEA’s work on gender equality, and apply for vacancies, internships or pipelines. 

Each atom consists of three types of particles: protons, neutrons, and electrons. At the centre of an atom is a dense nucleus, which contains protons and neutrons, and is much smaller than the entire atom. If the nucleus of the atom were the size of a marble, the atom would be the size of a sports stadium.

Protons have a positive electrical charge, while neutrons are neutral. The nucleus stays together due to the ‘nuclear force’. This force binds the protons and neutrons together at distances close to the size of the nucleus. The nuclear force at this distance is much stronger than the electrical repulsion between the protons (as they have equal charges, they would otherwise repel each other). At larger distances this nuclear force rapidly becomes insignificantly small. 

The number of protons in an atom’s nucleus determines which element it is. For example, an atom with one proton is hydrogen, while an atom with eight protons is oxygen.

Surrounding the nucleus is a cloud of electrons — negatively charged particles.  The atomic nucleus and the electrons are bound together by Coulomb force interactions – the forces in physics that describe the repulsion or attraction between these charged particles. However, when an electron gains energy, it can separate from the atom, causing the atom to become a positively charged ion.

Atoms with the same number of negatively charged electrons and positively charged protons are neutral, as the charges cancel each other out. If an atom gains or loses electrons it becomes an ion. 

In 1917, a scientist called Ernest Rutherford discovered that by blasting beams of radioactive alpha particles into nitrogen gas, the nitrogen atom could be transmutated into oxygen while ejecting a hydrogen nucleus. This subatomic particle (the hydrogen nucleus) was later renamed the proton. 

In the 1930s, scientists found out that if a neutron – an uncharged subatomic particle – is fired into certain uranium atoms, they could split into two and emit a certain number of neutrons, releasing a huge amount of energy along the way. This is called fission, from the Latin word for ’split’.

Uranium, with 92 protons, has the highest atomic number of all naturally occurring elements on Earth. Uranium-235 is easier to split (fission) than other isotopes because its nucleus is relatively unstable, and readily absorbs a neutron, causing it to break apart into two lighter atoms. However, only 0.7 per cent of uranium found on earth is this type of uranium, described as fissile.

Read more about uranium here.

Nuclear fusion is the process by which two light atomic nuclei combine to form a single heavier one while releasing massive amounts of energy, a theory first understood in the 1920s.

Fusion reactions take place in a state of matter called plasma — a hot, charged gas made of positive ions and free-moving electrons with unique properties distinct from solids, liquids or gases.

Like many other cities, Haiyang relied on coal to provide heating for its inhabitants.  Six years ago, that changed when turbines started turning at the Haiyang Nuclear Power Plant, which has been sending heat to homes in an ever-growing radius. The heat is entirely produced by nuclear power, with zero emissions, making it the first carbon-free heating system in China, and one of only a handful in the world.

Haiyang Nuclear Power Plant currently has two modern pressurized water reactors that generate around 20 billion kWh a year. These advanced reactors have a range of additional safety features and produce carbon-free electricity to power industries and communities in the region. 

Following a small pilot project in 2019, the Haiyang district heating project had expanded its operations to the entire city in 2021, expanding to Rushan, Weihai in 2023, and is now preparing to expand further to Qingdao City, where it will cover 200 million square meters and benefit five million people.

The project has already provided over 14 million gigajoules of zero-carbon heat, and reduced CO₂ emissions by 2.3 million tons by avoiding the burning of 1.3 million tons of raw coal, and is improving winter air quality in Haiyang and nearby Rushan.

 “Compared with other clean heating methods, nuclear heating is more stable, economical and eco-friendly with near-zero emissions,” said Liu Rong, Vice President of the China Urban Heating Association.

A key player in developing and maintaining the new heating system is Miao Zhengqiang, who runs Design Management at Haiyang Nuclear Power Plant. He explained why the project was launched. “First, as a clean energy enterprise, we aim to better fulfil our corporate social responsibility. At the same time, we strive to provide relatively affordable thermal energy to society.” 

Nuclear power plants generate a vast amount of hot steam – this is their entire goal, as the steam drives the generators that make electricity. However, constrained by the laws of physics, only about one-third of the heat in steam can be converted into electricity, while the majority of the remaining heat becomes waste heat.

To increase efficiency, a plant needs to put this heat to productive use. Instead of releasing it into the environment, the steam can be used for heating or cooling, or as an energy source to produce fresh water, hydrogen or other products, such as oil or synthetic fuel. These products could be produced by existing nuclear power plants with only a very small reduction in power output, in what is referred to as cogeneration.

“The basic design of our nuclear energy heating system utilizes the high-temperature, high-pressure steam generated by the nuclear power plant primarily for electricity generation. After electricity is produced, the remaining steam is used for heating,” said Zhengqiang.

The steam is used to heat water at the plant through heat exchangers, ensuring there is no radiation in the heated water delivered to apartment heating systems.

Thick white pipes snake out of the plant and carry this heated water to dispatch centres across the city – many of which used to be part of the old coal-powered heating systems but have since been cleaned out and upgraded with modern pumping and digital monitoring systems.

Dispatch Manager Li Changke has been heating Haiyang for his entire career, first by burning coal and now by transmitting the excess clean heat from the nuclear plant.

Standing in a shining space filled with pipes, next to a room filled with high-tech screens, he remembered how it was before: “There used to be a 40-ton coal-fired boiler in this room. At that time, the environment was polluted, and the floor was quite dirty. After switching to nuclear heating in 2021, we built a beautiful and bright nuclear heating dispatch centre. Now that we use nuclear energy for heating, we have no emissions of sulphur dioxide, nitrogen oxides, particulates and carbon dioxide.”

Sun Lingling, a pensioner in nearby Yasha Village, is quick to advocate for the benefits of the system. “After we switched to this nuclear energy heating system, we noticed the indoor temperature remained more stable, more consistently comfortable. The public also benefits financially, as the heating cost has been reduced,” she said.

Another small demonstration project shows that this heating system could even produce drinking water. In the nuclear power plant, seawater is desalinated using steam at lower temperatures, transforming it into clean, drinkable hot water, which is transported to the community through a single pipeline. In the community, the heat from the hot water is exchanged for heating, while the cooled water is supplied to residents for drinking. This conserves resources and energy, as heat generated during thermal desalination of water is often wasted.

“I would definitely explain to any who have doubts about the safety of the nuclear heating system that it is absolutely secure,” added Lingling. “We have been living here since the nuclear power station was built, and we have been using electricity generated from it without any problems. It is extremely safe. In the end, the air is cleaner and we are warmer. All my neighbours have the same positive response.”

Engineer Zhengqiang from the plant can never hear that enough. “Hearing residents share their satisfaction with nuclear heating brings me genuine joy. I believe this is a truly meaningful endeavour, and it makes me feel very proud.”

There is growing interest around the world in using nuclear energy for industrial applications such as seawater desalination, hydrogen production and district heating. District heating has been implemented in several countries – Bulgaria, China, Czech Republic, Hungary, Romania, Russia, Slovakia, Switzerland and Ukraine.

IAEA expert Francesco Ganda explained its appeal: “Countries are increasingly interested in the direct use of heat from nuclear plants, as it brings several benefits, including reduced carbon emissions, increased robustness and resilience of the entire energy system, reduced environmental pollution and increased efficiency for nuclear plants owners and operators. The possibilities extend to district heating, like in Haiyang, but also to nuclear-powered desalination, hydrogen production and providing heat directly to industry to decarbonize their operations.”

According to Huang Ping, Secretary General of China Atomic Energy Authority (CAEA), the Haiyang project is likely to expand across the region and beyond. “Nuclear heating projects are an important component of China’s green and low-carbon energy transition” he said. “China is willing to share its experience and practices related to nuclear heating with other countries to jointly tackle global climate change.”

Countries who wish to take advantage of the opportunities offered by nuclear cogeneration can receive support from the IAEA with research and training.

One of the IAEA’s most popular articles in 2025 was the explainer on What is Nuclear Energy?  Readers learned about how splitting atoms generates clean power without emitting greenhouse gases. 

Most nuclear reactors in operation today are fuelled by uranium. Read the What is Uranium? explainer to find out where uranium comes from, how it is processed and why a chicken-egg sized amount of uranium fuel provides as much energy as 88 tonnes of coal.  

Small modular reactors (SMRs) are making headlines as a way of powering data centres for artificial intelligence, and our explainer on these and other promising advanced nuclear reactors, were among the most read of 2025.

The Molten Salt Reactors explainer showed how passive safety systems in these types of reactors could enhance the safety of nuclear power plants and revealed that these reactors are being designed to use new types of fuels, such as thorium.

Nuclear fusion remains the ultimate energy goal, providing potentially limitless clean energy without greenhouse gases. Our What is Nuclear Fusion? explainer continued to rank among the most popular website content in 2025. Readers found out more about how fusion is developing around the world and how it differs from nuclear fission, which powers conventional reactors.

Beyond energy, the IAEA helps countries to benefit from nuclear science and technology in medicine, agriculture and food. Our isotopes explainer revealed how scientists use isotopes to find out the age and quality of water resources around the world and to track environmental pollution.  The radiopharmaceuticals explainer delved into how radioisotopes can be used to treat or diagnose cancer and heart disease. And our cyclotron explainer showed how these important radioisotopes are produced. 

Nuclear techniques can also bolster food security and sustainable agriculture as the IAEA’s explainers on food irradiation and the role of nuclear techniques in combatting soil erosion show. 

Nuclear safety and security, which enables people to benefit from nuclear technology while protecting them and the environment from the harmful effects of ionizing radiation, are some of the most important areas of the IAEA’s work. In 2025, the What is Radiation? explainer helped readers understand the different types of radiation, its beneficial uses in health, energy, agriculture and industry and the safety measures that can protect people from harmful exposure to ionizing radiation. 

For those wanting to dive deeper, an explainer on the universal radiation symbol highlighted how international standardization leads to greater public awareness of the risks of ionizing radiation, reducing the risk of accidental exposure.

Finally, the story of Oklo, a natural nuclear reactor in Gabon, captured the imaginations of many readers. It shows that nuclear reactions occurred naturally in uranium deposits in western Equatorial Africa, long before the first dinosaurs appeared. The IAEA article Meet Oklo: Earth’s Two-Billion-Year-Old Natural Reactor will tell you more.

The popularity of these explainers shows a world eager to understand nuclear science and technology and benefit from clean energy, better health, enhanced agriculture, innovation and more. 

Find more ‘Nuclear Explained’ articles, as well as videos and podcasts in this series, here.