IAEA Profile: When Passion Meets Purpose to Protect Ocean Health

Source: International Atomic Energy Agency (IAEA) –

Hatje knew little about nuclear techniques when she began studying oceanography, but that changed when she moved from Brazil to Sydney, Australia, to pursue a PhD. She conducted most of her experimental work at the Australian Nuclear Science and Technology Organization (ANTSO). “It was my first experience using nuclear techniques to study processes that control the levels of trace metals – such as zinc, iron and chromium – in water. I applied these techniques while conducting marine pollution research in Sydney Harbour.”  

Later, she used nuclear techniques to determine the chronology of environmental contamination of several marine ecosystems in Bahia, Brazil. She extracted cores of sediment from the coastal and ocean floor, a method that preserves the integrity of sediment layers. “I used dated sediment cores to examine the historical record of pollution,” she said, “and I correlated the data to the diverse human activities and how they changed over time.”  

Hatje’s educational journey prepared her for a new challenge to establish labs and projects focused on the marine environment at the Federal University of Bahia in a chemistry department that had never before supported ocean research. Around this time, Hatje began to work with a scientist who helped her navigate the Brazilian academic system. “I had the opportunity to work with a highly esteemed Brazilian scientist. Together, we managed two large projects,” she said. “I learned a great deal from my colleague – how to run a research group, how to successfully secure large grants and the importance of having a strong network.”  

One of Hatje’s greatest professional achievements is one that led to practical change. In 2013, while on a sabbatical at the University of California at Santa Cruz in the USA, Hatje had the chance to apply a method she had developed to evaluate rare earth elements in seawater to 20 years of water samples from San Francisco Bay. She found evidence of increasing levels of gadolinium, a naturally occurring element that is used as a contrast agent to increase the resolution of magnetic resonance imaging. “At the end of the day, this research had a very practical outcome that changed the monitoring programme of the area, with gadolinium now included in routine measurements of water quality in the Bay.” 

The IAEA’s Transportable E-Beam System

Source: International Atomic Energy Agency (IAEA) –

Electron beam (e-beam) technology is an industry work horse in 40 countries today to improve the safety and quality of materials. It works by using high energy electrons to treat products, making them cleaner, stronger or more durable. The IAEA’s Transportable Electron Beam System is breaking barriers by making this technology more accessible worldwide. This mobile and versatile system can process liquids, gases and solids, supporting innovation across industries such as health care, construction, food and agriculture, cultural heritage preservation, and environmental cleanup.

Update 336 – IAEA Director General Statement on Situation in Ukraine

Source: International Atomic Energy Agency (IAEA) –

The IAEA has initiated consultations to establish a temporary ceasefire zone in the area where Ukraine’s Zaporizhzhya Nuclear Power Plant (ZNPP) last remaining back-up 330 kV line was damaged and disconnected as a result of military activity on 2 January, leaving the plant entirely dependent on its sole functioning 750 kV line, Director General Rafael Mariano Grossi said today.

The proposal requests both the Russian Federation and Ukraine to agree to a temporary ceasefire zone at a location approximately 10 kilometres from the Zaporizhzhya Thermal Power Plant 330 kV open switchyard, to enable Ukrainian technicians to safely perform the necessary repairs.

The latest ceasefire proposal comes after successful repairs were carried out under an IAEA-brokered local ceasefire on 30 December, marking the third time in recent months when  temporary truce arrangements negotiated and overseen by the IAEA allowed work on power lines critical for nuclear safety that had been damaged during the conflict. 

“The IAEA remains actively engaged with both parties to ensure nuclear safety and security at the plant,” said Director General Grossi. “We are confident that the Russian Federation and Ukraine will continue to cooperate constructively with us to carry out these essential repairs and reduce the risk of an accident.”

Over the past week, the IAEA team present at the ZNPP has also reported a significant increase in military activities in the areas surrounding the ZNPP, including some explosions heard close to the site. 

Throughout Ukraine, IAEA teams present at the country’s operating nuclear power plants (NPPs) – Khmelnytskyy, Rivne and South Ukraine – and the Chornobyl NPP site have reported that military attacks on the country’s electrical infrastructure continue to impact nuclear safety at the plants. One NPP reduced its power output on 25 December when military activity caused one power line to be damaged and disconnected. 

Due to persistent military activity on the country’s power infrastructure Director General Grossi announced that the IAEA is preparing another expert mission to Ukraine’s electrical substations. 

“These substations are critical for nuclear safety and security as they supply electricity for reactor cooling and other essential safety systems. The IAEA has the expertise to assess the direct implications of the continued deterioration of Ukraine’s power grid on the safety of its nuclear power plants,” he added. 

In the past weeks, two deliveries were completed as part of the IAEA’s comprehensive programme of assistance to Ukraine. The deliveries consisted of radiation portal monitors intended for the Kharkov Institute of Physics and Technology and six water level meters for the South-Ukrainian subdivision of the State Enterprise “Ukrainian Geological Company” within the framework of the IAEA Support and Assistance Mission to the Kherson Oblast (ISAMKO) programme. The deliveries – which brought the total number of shipments to Ukraine to 196 since the start of the war – were made possible with funds from Japan and Sweden.

The Year Ahead: Key Events at the IAEA in 2026

Source: International Atomic Energy Agency (IAEA) –

Emma Midgley, IAEA Office of Public Information and Communication

From strengthening safeguards and helping countries build resilient nuclear fuel supply chains to enhancing radiation protection for patients, 2026 will be an eventful year for the IAEA and its global community. 

Among the many highlights of the year, the 70th IAEA General Conference will take place from 14 to 18 September in Vienna. Nuclear decision makers from countries around the world will come together to chart the Agency’s future and reaffirm their commitment to the peaceful, safe and secure use of nuclear science and technology. 

This milestone session will reflect on seven decades of impact while addressing the challenges and opportunities ahead — from nuclear energy to the IAEA’s work in cancer care, industry and food security. Below is a guide to some of the major conferences, symposia and other events planned in 2026 by the IAEA.

March — Nuclear Energy Summit

Nuclear Energy Summit
10 March, Paris, France.

The second Nuclear Energy Summit will be hosted by the Government of France in Paris. It follows on from a previous nuclear energy summit in 2024, in which world leaders gathered in Brussels to highlight the role of nuclear energy in enhancing energy security and boosting economic development.

International Conference on the Safe and Secure Transport of Nuclear and Radioactive Material 
23–27 March, Vienna, Austria

Every year, around 20 million shipments of nuclear and radioactive material support peaceful uses of nuclear technology in energy, medicine, industry, agriculture and research. In March, stakeholders will convene in Vienna to explore how design certification, regulatory frameworks, supply chains and new technologies can reinforce safety and security across all transport modes. 

Find out more at the conference website.

The IAEA conducts field exercises on transport security of nuclear material. (Image: IAEA)

April — Enhanced Nuclear and Radiation Safety and Security through Regulatory Systems

International Conference on Effective Nuclear and Radiation Regulatory Systems (RegCon2026)
27–30 April, Vienna, Austria

Regulators and stakeholders will share practices for effective, agile and connected regulatory “ecosystems” that keep pace with innovation and emerging challenges. The 2026 edition follows Abu Dhabi 2023 and earlier meetings since 2006, with a focus on sharing good practices and experiences across the global regulatory community to further enhance nuclear and radiation safety and security. 

The IAEA has worked with researchers to carry out cyberattack simulations on a simulator.

May — Computer Security in the Nuclear World

International Conference on Computer Security in the Nuclear World: Securing the Future (CyberCon26
11–15 May, Vienna, Austria

As digital systems play an essential role in all aspects of the management and safe and secure operation of nuclear facilities, CyberCon26 will address computer security and potential threats and risks. The conference will bring together regulators, operators and specialists to explore six core themes from computer security by design to emerging digital technologies. 

5th International Conference on Fast Reactors and Related Fuel Cycles (FR26)
18–21 May, Beijing, China

Fast neutron reactors — and the fuel cycles that support them — are widely recognized as key to the long term sustainability of nuclear power. Compared to conventional thermal reactors, fast reactors can extract far more energy from uranium while significantly reducing high-level radioactive waste. Hosted by China in 2026, FR26 will build on prior conferences (Kyoto 2009, Paris 2013, Yekaterinburg 2017, Vienna 2022), engage young professionals, and spotlight progress in sodium, lead, gas and molten salt cooled concepts, as well as how fuels and fuel cycles can be developed for these advanced systems. 

Read more: What are Molten Salt Reactors

The E-beam facility is currently located at the IAEA’s laboratories in Seibersdorf, Austria. (Image: IAEA)

June — E-Beams for Industry, Environment and Research

Training Workshop on the Transportable Electron Beam System 

17–19 June, IAEA Seibersdorf Laboratory, Austria

The workshop forms part of the IAEA’s ongoing efforts to strengthen the technical capacity of its Member States in the application of advanced radiation technologies for industrial, environmental and research purposes.

A transportable electron beam system was launched during last year’s IAEA General Conference to be loaned out for training and experiments.

IAEA International Conference on Accelerators for Research and Sustainable Development
22–26 June, Vienna, Austria

Particle accelerators have many applications in science and industry, with significant societal and economic impact in areas such as health, environment, food safety, energy and cultural heritage. The second conference in this series will highlight advances in compact and large facilities, best practices in sustainable operation, and accelerator enabled solutions aligned with the IAEA flagship initiatives Atoms4Food, Atoms4NetZero, NUTEC Plastics, Rays of Hope and ZODIAC

Read more: What are Particle Accelerators? 

June–July — Learning from the Past to Enhance Safety at Nuclear Installations

International Conference on Topical Issues in Nuclear Installation Safety (TIC2026)
29 June–3 July, Vienna, Austria

Since 1998, Topical Issues in Nuclear Installation Safety Conferences (TICs) have provided a global platform to share best practices at nuclear installations, from design, siting and construction to operation and regulation. TIC2026 will emphasize how insights gained from past projects and events can help to make future projects more effective, efficient and safe. The conference will address both continuous safety improvements for nuclear power plants currently in operation and strengthening the safety of advanced designs such as small modular reactors (SMRs) and next generation nuclear power plants. 

Read more: What are Small Modular Reactors?

September – IAEA General Conference

IAEA General Conference 2026
14-18 September Vienna, Austria

Every year in September, leaders, scientists and representatives of our 180 member countries gather in Vienna for one of the biggest annual events for nuclear decision-making: the IAEA General Conference. Delegates debate and decide on issues that shape the agency’s work — from budgets and programmes to peaceful uses of nuclear science and technology and energy. 

The General Conference helps set the IAEA’s course for the year ahead, ensuring that its activities remain effective, relevant, and responsive to global needs

October — Enhancing Radiation Medicine Patient Safety

October  —  International Symposium on Standards, Applications, and Quality Assurance in Medical Radiation Dosimetry (IDOS3)

5-9 October Vienna, Austria

Medical radiation dosimetry refers to the science and practice of measuring the dose of ionizing radiation delivered to a patient during diagnostic or therapeutic procedures. IDOS3 will continue the work of previous symposia in 2010 and 2019 reviewed advances in dosimetry standards, audits and quality assurance across radiotherapy, diagnostic radiology and nuclear medicine, underpinning patient safety and measurement traceability. 

Read more: What is Radiation Therapy? 

What are Radiopharmaceuticals?

Building Resilient Fuel Supply Chains for a Sustainable Future International Conference on Fuel Supply Chain for Sustainable Nuclear Power Development

13–15 October, Vienna, Austria

With countries planning to expand nuclear power to meet climate and energy security goals, the front end of the fuel cycle — from uranium exploration to enrichment and fabrication — faces rising demand. The conference will address conventional fuels and advanced nuclear fuels such as HALEU, which is uranium enriched up to 20%, for advanced reactors.  It will also explore other aspects of the supply chain, such as new fuel design concepts, circular economy approaches and other innovations. An essay competition for young professionals invites early career perspectives ahead of the event. 

Read more: IAEA Launches Competition on Nuclear Fuel Supply Chain

November — Safeguards Symposium

Symposium on International Safeguards
9-13 November, Vienna, Austria

Held every four years, the IAEA Symposium on International Safeguards brings together global stakeholders in support of IAEA safeguards. It is an opportunity for safeguards regulatory authorities, the research and development community, industry and civil society to identify challenges and opportunities for IAEA safeguards, highlight research, share ideas, and build partnerships. The 2026 symposium follows the 2022 event Reflecting on the Past and Anticipating the Future

December — Managing Nuclear Power Plants for Decades of Safe, Reliable Operation

6th International Conference on Nuclear Power Plant Life Management (PLiM 6)
7–11 December, Tokyo, Japan

With the average global reactor age now over 30 years, long term operation hinges on effective ageing management of structures, systems and components. The PLiM 6 conference will share strategies, innovations and programme approaches that sustain safety and performance — supporting the long term operation of nuclear power plants beyond 60 years. 

Nuclear Power Ministerial Conference

A ministerial level gathering on nuclear power is under consideration. Details will be published on the IAEA events portal. 

Board of Governors

The IAEA’s Board of Governors will meet in March 2-6, June 08-12, before and after the General Conference on September 7-11 and September 21 and from November 16-20, when it will include the technical assistance and cooperation committee (TACC). 

For a comprehensive list of all the meetings and events in 2026 at the IAEA, click here.

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IAEA’s Marine Radioactivity Information System Transforms Ocean Research

Source: International Atomic Energy Agency (IAEA) –

The IAEA Marine Radioactivity Information System offers over a million verified records of data related to marine radioactivity to help experts track, understand and protect our oceans.

The IAEA’s Marine Radioactivity Information System (MARIS) is used by scientists, policymakers and experts use the system to assess radionuclide levels and trends in marine environments. (Photo: IAEA)

The IAEA has expanded global access to critical ocean data through its Marine Radioactivity Information System (MARIS), an open platform that hosts more than one million verified radioactivity records from seas and oceans worldwide. Freely accessible online for 20 years, the system is helping scientists and policymakers track changes in marine environments with transparency and consistency. 

Environmental monitoring and scientific research generate vast amounts of valuable data, yet much of it remains inaccessible. Access restrictions, incompatible formats, missing metadata, poor provenance, unclear licensing and fragmented storage often prevent scientists from sharing and building on each other’s work.  

MARIS was developed to overcome these barriers. Its radioactivity records are verified through the IAEA Marine Environment Laboratories in Monaco. The laboratories’ expertise guides key datasets and drives the continuous development of MARIS in line with evolving user needs. MARIS records are also standardized, documented and offer full provenance records for scientific reuse. 

“What makes MARIS unique is not just the volume of data, but the rigorous quality assurance behind every record,” said Paul McGinnity, Research Scientist at the IAEA Marine Environment Laboratories. “Before any data enters the system, our team validates the analytical methods, checks for consistency, and ensures proper documentation. This quality control is what gives scientists worldwide the confidence to use MARIS data for critical environmental assessments and policy decisions.” 

MARIS data supports a wide range of applications. Scientists, policymakers and experts use the system to assess radionuclide levels and trends in marine environments, validate computational models of radionuclide transfer and support environmental monitoring. As the ocean faces mounting pressures from climate change, marine plastic pollution and ocean warming, access to reliable radioactivity data is increasingly vital.  

“The standardized format and open access nature of MARIS data has greatly enhanced our ability to collaborate with neighbouring countries on marine radioactivity research,” said Bao Li, Associate Researcher at the China Institute for Radiation Protection. “For comprehensive environmental protection in the Asia-Pacific region, we need this kind of shared, verified data foundation.” 

The IAEA periodically gathers information from its Member States to track the amount of radioactive materials that have entered the world’s oceans and seas. Scientists perform Rosette sampling in the ocean, Monaco. (Photo: IAEA)

MARIS enables users to filter data by year, region, radionuclide, data source and, when applicable, depth and species. Its extensive database includes measurements of radionuclides in seawater, biota, sediment and suspended matter, providing a robust record across time and location. MARIS also provides essential baseline data for comparing radionuclide levels before and after human activities, such as planned discharges from nuclear facilities or unplanned releases following nuclear or radiological incidents. With records dating back to 1957, MARIS helps researchers track long-term trends in marine radioactivity.  

The system draws on data from diverse global sources, including national monitoring programmes and regional organizations, such as the Baltic Marine Environment Protection Commission, the Convention for the Protection of the Marine Environment of the North-East Atlantic and the Asia and Pacific Marine Radioactivity Database. Additional data are extracted from peer-reviewed scientific publications. 

MARIS also contributes to the global movement toward open data, data reuse and open science. To be included in MARIS, data must be freely available for redistribution and reuse by anyone, at anytime and anywhere—a commitment that promotes transparency, supports research and enables reanalysis.  

MARIS data inform environmental regulations in dozens of countries, strengthen emergency preparedness and response planning for nuclear incidents and underpin research that safeguards millions of people whose livelihoods depend on marine resources.  

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IAEA Profile: Hannah Affum: Breaking Barriers with Radiotracers and Resilience

Source: International Atomic Energy Agency (IAEA) –

Featured Story

Hannah Affum, went from mixing household chemicals as a child in Ghana to launching the IAEA’s Non-Destructive Testing (NDT) Centre, showing that science thrives on passion, not stereotypes.

Sophie Ramirez, IAEA Department of Nuclear Sciences and Applications

Hannah Affum in a project coordination meeting in Warsaw, Poland in October 2024. (Photo: M. Zych/AGH University of Science and Technology, Poland)

The IAEA profiles employees to provide insight into the variety of career paths that support the Agency’s mission of Atoms for Peace and Development and to inspire and encourage readers, particularly women, to pursue careers in STEM (science, technology, engineering and mathematics) or STEM-adjacent fields. Read more profiles of women at the IAEA.  

For Hannah Affum, a chemical engineer turned nuclear scientist, curiosity has always been her compass. From mixing household chemicals as a child in Ghana to launching the IAEA’s Non-Destructive Testing (NDT) Centre, her journey defied expectations — and shows that science thrives on passion, not stereotypes.

A Spark for Science

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.

Hannah Affum demonstrating how radiotracers help to understand flow processes to a group of scientists in the IAEA’s radiotracer laboratory. (Photo: S. Liu/IAEA)

Challenges and Champions

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!”

An Unexpected Path to the IAEA

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.

Advocating for Women — and the Power of Nuclear

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.”

Hannah Affum at the recent ICARST conference opening at IAEA headquarters. (Photo: M. Klymenko)

The IAEA’S Commitment to Gender Equality

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

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What is an Atom?

Source: International Atomic Energy Agency (IAEA) –

Emma Midgley, IAEA Office of Public Information and Communication

An atom is the smallest unit of an element that retains its chemical properties. It is made of protons, neutrons, and electrons. (Image: M. Magnaye)

Atoms are the building blocks of matter. Everything around us — from air and water, to rocks, plants and animals — as well as everything within our bodies, is made up of atoms.

They are very small,  the smallest units of an element that retain the element’s chemical properties. The Ancient Greeks believed they were the smallest particles in existence, and the word ‘atom’ is derived from ‘indivisible’ in Greek. A single strand of human hair is as thick as 500 000 carbon atoms stacked on top of each other. 

This single atom of the metal strontium is visible in this photograph because it has absorbed and re-emitted the light of a laser. The electrodes in the picture are two millimetres apart. (Photo: David Nadlinger/Oxford University)

Atoms cannot be seen with the naked eye, or even under a standard microscope. An atom is too small to deflect visible light waves, meaning it will not show up under light-focusing microscopes. Atoms can be viewed under an electron microscope, which generate electron waves that can interact with atoms. In the picture above, the atom is ‘visible’ because it has absorbed and re-emitted the light of a laser.

What do atoms look like? Scientists have changed their minds over the centuries. (Infographic: M. Magnaye)

What are Atoms Made Of?

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.

The atom at the centre of the IAEA’s logo has four electrons – meaning it is Beryllium if it is neutral and not ionized. (Infographic: M. Magnaye)

What are Ions?

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. 

(Infographic: M. Magnaye)

While the electric field of a neutral atom is weak, an electrically charged or ionized atom has a strong electrical field, making it strongly attracted to oppositely-charged ions and molecules. Atoms can be ionized by collisions with other atoms, ions and subatomic particles. They can also be ionized by exposure to gamma or X ray radiation. Ionizing radiation refers to radiation that has enough energy to break an electron away from an atom. It can also chemically alter material, for example damaging DNA in living tissue.

(Infographic: M. Magnaye)

Most atoms on Earth are stable, mainly thanks to a balanced composition of particles (neutrons and protons) in their nucleus.

However, in some types of unstable atoms, the composition of the number of protons and neutrons in their nucleus does not allow them to hold those particles together. In this case, the atom ‘decays’, and releases energy in the form of radiation (for example alpha particles, beta particles, gamma rays or neutrons), which, when safely harnessed and used, can produce various benefits.

 Read more: What are Isotopes?

(Infographic: M. Magnaye)

Ernest Rutherford: Inventor of the ‘Atom Smasher’

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. 

(Infographic: M. Magnaye)

Rutherford’s discovery led to the development of the first particle accelerator, initially referred to as an ‘atom smasher’. This powerful machine could accelerate charged particles using an electrical field to high energies along a path and used strong magnets to create beams of single charged particles. When the fast-moving particles hit the target (they could go almost as fast as the speed of light), the atoms in the target split apart.

 Read more: What are particle accelerators?

Particle accelerators also can be used to create radioactive material by shooting charged particles at atoms to change them into different, unstable atoms, such as Technetium-99m for medical imaging and radioisotopes for targeted cancer therapy.

Read more about radioisotopes here.

Today, particle accelerators are also used to sterilize medical equipment, , research the origins of the universe (for example, at the Large Hadron Collider), as well as to analyse air samples  and to enhance materials and make them more resistant to damage. Different types of particle accelerators include ion implanters, electron beam accelerators, cyclotrons, synchrotrons, linear accelerators (Linacs and electrostatic accelerators.

Splitting the Atom: Nuclear Fission

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.

(Infographic: M. Magnaye)

Fission can be used to create a nuclear chain reaction. Every time a uranium-235 atom is split it releases on average 2.5 neutrons. These can go on to split further fissile nuclei, releasing yet more neutrons. However, these ‘fast’ neutrons initially travel with too much energy to be effective at causing fission. Using a ‘moderator’ such as water or graphite slows down the neutrons. The neutrons lose most of their energy in collisions with the hydrogen or carbon atoms to become ‘thermal’ or ‘slow’ neutrons which have a much better chance of splitting other uranium nuclei.

The nuclear fission technique is now used to make 10% of the world’s carbon-free energy — as nuclear fission produces no carbon dioxide. 

What happens to Atoms in Nuclear Fusion?

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.

(Infographic: M. Magnaye)

The sun, along with all other stars, is powered by this reaction. To fuse, nuclei need to collide with each other at extremely high temperatures, around one hundred million degrees Celsius. The high temperature provides them with enough energy to overcome their mutual electrical repulsion. Once the nuclei come within a very close range of each other, the attractive nuclear force between them will outweigh the electrical repulsion and allow them to fuse. For this to happen, the nuclei must be confined within a small space to increase the chances of collision. In the sun, the extreme pressure produced by its immense gravity creates the conditions for fusion.

Read more about fusion energy in our explainer ⇢

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IAEA Profile: From Football Field to Nuclear Safety

Source: International Atomic Energy Agency (IAEA) –

Working her way up, Calabria moved to the CNEN at headquarters in Rio de Janeiro as a nuclear safety and radiation protection inspector at nuclear power plants. At the same time, she joined the Brazil branch of Women in Nuclear (WiN), an organization of likeminded women, where she was elected as vice president in 2020.

Although she was aware of the IAEA “for the best of the best”, she didn’t see herself being part of it.

Others saw her differently. 

“Jaqueline has a rare sense of collective effort and expects no personal recognition. She truly believes in the power of collaboration and setting a personal example as a way to encourage women and girls,” said Danila Dias, WiN president at the time.

“It was WiN that helped me overcome my doubts,” says Calabria. 

Since joining the IAEA in 2022, Jaqueline has achieved several professional accomplishments. She has overseen the redesigned and maintenance of the Database on Discharges of Radionuclides to the Atmosphere and the Aquatic Environment (DIRATA), which facilitates the transparent reporting of radioactive releases from nuclear and radiation facilities around the world. 

She also led the drafting of a new General Safety Guide on Monitoring for Protection of the Public and the Environment (No. GSG 19),  guiding and  monitoring radioactive releases to ensure public and environmental safety. 

Calabria champions early career professionals, designing workshops and activities under the IAEA programme on Methods for Radiological and Environmental Impact Assessment to help them develop their expertise. 

A leader in her field, in 2025 Calabria led on the field as well, she captained the IAEA women’s football team to victory at UNESCO’s Inter-Agency Games in Rennes, France.

“Football taught me discipline and persistence. Even now, these principles are at the heart of everything I do and guide my work to help protect people and the environment,” said Calabria.

Her advice for the generation? “Surround yourself with people who see your potential, even when you don’t see it yourself.” 

Carbon-free Heating Keeping Chinese City Warm and Clean

Source: International Atomic Energy Agency (IAEA) –

Katy Laffan, IAEA Office of Public Information and Communication

Pensioner Jiang Fuxue is an avid gardener. Even during winter snowstorms in his hometown of Haiyang in Northern China, he tends to the plants in his home in a balmy 23 degrees Celsius. For many around the world, keeping an apartment this warm in winter would be unaffordable, or at least not recommended in the light of climate challenges, but Jiang does not get heat from a traditional source. His home, and those of the other 400,000 residents around Haiyang are warmed with heat produced by the local nuclear power plant.

“Outside may be cold, but in here it is always spring,” said Jiang, 60, a retired worker at one of the now defunct coal-fired heating plants, many of which are now being retrofitted to run the new nuclear heating system.

Pensioner Jiang Fuxue enjoys the new nuclear heating system, which he says provides affordable and stable heat to his apartment in Haiyang, China. (Photo: IAEA)

Haiyang’s District Heating Project

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.

Engineers at the Haiyang Nuclear Power Plant walk through the ‘Warm U-Clear’ building, where steam from the plant is used to heat desalinated seawater, which is then pumped through these pipes to residents in nearby towns. (Photo: IAEA)

Reducing Carbon Emissions

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.” 

Making the Most of All Available Steam

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.

Excess heat from the nuclear power plant is also being used to grow mangroves around the coast, in a pilot project to improve the local environment. (Photo: IAEA).

Moving From Coal to Nuclear

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.”

Affordable Heat

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.”

Global Interest in District Heating

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.

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Japan Continues to Meet International Safety Standards in Discharge of ALPS-Treated Water, IAEA Task Force Confirms

Source: International Atomic Energy Agency (IAEA) –

The discharge of ALPS (Advanced Liquid Processing System)-treated water from Japan’s Fukushima Daiichi Nuclear Power Station (FDNPS) is progressing in line with relevant international safety standards, the International Atomic Energy Agency (IAEA) Task Force confirmed this week following its latest five-day mission to Japan, conducted from 15 to 19 December. The mission included on-site inspections of the facilities used for the discharge at the FDNPS.

The IAEA Comprehensive Report on the Safety Review of the ALPS-Treated Water at the Fukushima Daiichi Nuclear Power Station, published in July 2023, concluded that Japan’s approach to discharging the treated water is consistent with international safety standards and that the planned discharge would have a negligible radiological impact on people and the environment.

This mission marks the tenth for the Task Force since the beginning of the IAEA’s multiyear safety review in 2021. The Task Force includes IAEA staff and 11 international experts from Argentina, Australia, Canada, China, France, the Marshall Islands, the Republic of Korea, the Russian Federation, the United Kingdom, the United States and Viet Nam.

“Japan has demonstrated continued effort and commitment to ensuring that the discharge of ALPS-treated water is implemented in line with relevant international safety standards,” said Gustavo Caruso, Chair of the Task Force. “The Task Force noted Japan’s ongoing work to carry out the discharge in accordance with these standards and underscored that the IAEA will continue its independent safety review throughout the process to provide transparency and compliance.” 

During this week’s mission, the Task Force focused on activities conducted since the start of the discharge and followed up on technical topics important for safety. In Tokyo, the Task Force met with officials from the Ministry of Foreign Affairs, the Nuclear Regulation Authority, the Ministry of Economy, Trade and Industry, as well as representatives from Tokyo Electric Power Company Holdings (TEPCO), the operator of the FDNPS.

The Task Force also conducted its fifth visit to the ALPS-treated water discharge facilities at the FDNPS since the start of the discharge in August 2023. Through direct observations of facilities and equipment, including a visit to the TEPCO Chemical Analysis Building, the Task Force had the opportunity to observe the laboratory activities carried out by TEPCO related to tritium measurements on ALPS-treated water samples. The Task Force also visited the IAEA on-site laboratory, where the Agency conducts independent monitoring and corroboration of the radioactive concentration.

The Task Force observed the status of the tanks dismantling activities after discharge, which had been visited during the previous mission, and noted that TEPCO has continued to make progress in the decommissioning of these tanks that contained ALPS-treated water. The Task Force also noted that the equipment and facilities are installed and operated in accordance with Japan’s Implementation Plan and relevant international safety standards.

The IAEA’s interlaboratory comparisons – carried out since before the discharges – continue to provide a comprehensive verification of the accuracy and reliability of the monitoring data reported by TEPCO and the Government of Japan. Additionally, the IAEA’s onsite sampling and analysis – conducted at FDNPS since July 2023 – has confirmed that the tritium concentration in the first 17 batches of diluted ALPS treated water remains consistent with international safety standards, far below Japan’s operational limits. Radiation monitors and flow rate detectors at the site also feed live data to the IAEA’s dedicated real-time monitoring page.

Further, the IAEA conducts additional measures, which focus on expanding international participation and transparency, allowing hands-on independent measurements of the concentration level of the ALPS treated water. The latest mission carried out under the additional measures took place in December 2025.

As the main conclusion, the Task Force did not identify any inconsistencies with the requirements of relevant international safety standards, reaffirming the conclusions of the Task Force’s safety review as outlined in the Comprehensive Report of 4 July 2023. Detailed outcomes from the Task Force’s review mission this week will be summarized in a report to be made publicly available next year. 

The reports on the first four review missions held by the Task Force since the start of the water discharge are available online.