The Hamadohri Environmental Radiation Measurement International School took place in Fukushima, Japan, from July 27 to 31, 2025. It was jointly organized by Osaka University and the NPSS Educational Committee (EduCom). This marked the second time both have collaborated to host this topical school centered on the Great East Japan Earthquake of March 11, 2011. The school aims to deepen students’ understanding of the regional situation following the Fukushima nuclear accident and to encourage them to reflect critically on the broader implications.

From over 70 applicants, a total of 32 international participants from 12 different countries were selected, some of them following a video interview assessing their English-speaking and comprehension skills. The group included graduate, master’s, and PhD students, as well as two teachers from the United States. About half of the participants came from Southeast Asian countries such as Indonesia, Malaysia, and the Philippines, along with others from Saudi Arabia, Taiwan, and Mexico — ensuring a rich diversity of cultures and educational backgrounds. More than half of the participants were women.

The school began with a visit to the restricted area around the Fukushima power plant, where the Japanese government has undertaken a massive cleanup effort by removing topsoil, grass, and other contaminated materials from an area spanning several dozen square kilometers. To our surprise, a vast landfill — covering the area of multiple football fields and stacked with eight one-meter layers of contaminated soil — had been capped with a thin layer of approximately 30 centimeters of clean soil, which reduces the radiation to near-background levels. The students used Radiacode-102 portable detectors to identify remaining radiation “hot spots”, as well as areas that had been fully decontaminated.

Later, in the classroom, participants learned how to extract tracking data from the detectors and uploaded it to Google Maps using modern tools such as ChatGPT to generate Python code, which they ran in a Jupyter Notebook.

The resulting tracks from all groups provided a good understanding of “low dose rate” and “high dose rate” environments, especially when compared to the dose received by air travel. It turned out that the total accumulated dose during the entire school (approximately 18 µSv) was about the same as the dose received by the author during the round-trip flights between Zurich and Tokyo, where the return flight went over the North Pole.

In the afternoon, the school visited the Fukushima Daiichi Nuclear Power Plant, where we learned about the ongoing decommissioning efforts for the four damaged and two relatively undamaged reactor blocks. Contaminated cooling water gets purified in a newly built filter facility that removes 62 radioactive isotopes—except tritium—to below detectable levels. The remaining tritium, which is bound in water molecules, is then diluted with seawater and discharged into the ocean at a concentration approximately one-seventh of the WHO drinking water standard.

Although all the recovery efforts were truly impressive, it was also evident that the complete decommissioning—especially of the melted reactor cores—will require significantly more time and effort.

The second day began with soil sampling. Students and teachers entered the restricted area to collect samples from contaminated sites, including soil cores approximately 30 cm deep, as well as leaves and other biological materials such as dried worms. These samples were later carefully examined in the school laboratory, where their radioactivity was measured in becquerels per kilogram. Using the spectral analysis capabilities of the Radiacode-102 and the NaI detectors in the lab, the main radioactive isotopes were identified. It turned out that only the first ~10cm of the topsoil are contaminated mainly with Cs-137, while deeper soil, leaves and other plants have a relatively small radioactivity.

The final day of the school was dedicated to a group of eight local residents, who shared their personal experiences during and after the Great Eastern Japan Earthquake. They spoke candidly about the initial shock of the disaster, the challenges of evacuation, and the long road toward rebuilding their lives and communities. Their stories offered a deeply human perspective on the consequences of the nuclear accident—beyond technical and scientific aspects—and provided valuable insights into the social and emotional dimensions of recovery. The participants had the opportunity to engage in an open dialogue with the residents, asking questions and reflecting on the resilience and strength shown by those affected.

Many residents not only suffered direct damage from the earthquake, the tsunami, and the subsequent nuclear accident, but also faced a range of secondary hardships. These included uncertainty and discomfort in evacuation centers, the fragmentation of once-close communities, as well as experiences of discrimination and the spread of harmful rumors. Despite these challenges, there was a strong sense of resilience and determination to rebuild. A positive spirit of recovery could be felt throughout the region, with local communities working to restore what was lost. Remarkably, many foreign volunteers and professionals have even chosen to settle in the area permanently, contributing to its revitalization and supporting long-term recovery efforts.

The school ended with a common barbecue of students, teachers, organizers, and some of the residents. Locally harvested vegetables, mushrooms, and fish was served. Some of us couldn’t resist putting our dosimeters to work, but every reading stayed at the background level. We concluded that the only thing glowing was our appreciation for the excellent food.

While most of us had only a limited awareness of the situation through mass media, the hands-on experience of visiting the affected area, conducting direct measurements, and studying the biological effects from a scientific perspective provided both students and teachers with a much deeper understanding. This immersive approach encouraged students to reflect critically on how they should respond to such events, what roles they might play in the future, and how Japan could address reconstruction, disaster preparedness, and energy policy. At the end of the program, each participant gave a final three-minute presentation before receiving their certificate of attendance. These talks revealed just how deeply they had been impacted by the discussions, discoveries, and the rich, multicultural spirit of the school. A week nobody will forget.

On behalf of the organizing committee, we would like to express our sincere gratitude to all the lecturers, exercise tutors, and the local support team. We are deeply grateful for the financial and logistical support provided by NPSS (EduCom, Early Career Travel Grant Initiative), the University of Osaka, and the IAEA.

Stefan Ritt, Chair of the IEEE NPSS Education Committee, can be reached by E-mail at [email protected]