In November 2025, the NEA hosted the 7th Fukushima Daiichi Nuclear Power Station Accident Information Collection and Evaluation (FACE) Project meeting at Politecnico di Milano, Italy, bringing together experts from around the world to discuss the latest findings and future challenges related to the Fukushima Daiichi accident and fuel debris analysis. During the meeting, experts also developed a plan for extending this project until the beginning of 2027 and launching a new phase in early 2027.
Technical progress and key discussions
Advances in fuel debris analysis
Significant progress was reported in the characterisation of fuel debris retrieved from Unit 2 at Fukushima Daiichi Nuclear Power Sation. Detailed analyses — including SEM-EDS, X-ray CT, and TEM — revealed the distribution of uranium, zirconium, iron, and nickel, as well as the presence of multi-phase structures. These findings have improved the understanding of the mixing and solidification processes that occurred during the accident. Additional analyses are planned to inform fuel retrieval and analysis of the accident.
Aerosol generation and mitigation
New experimental data were presented on possible aerosol release during mechanical and laser cutting of debris. The effectiveness of wet cutting, mist sprays, and other mitigation techniques was quantified, and computational models for aerosol removal efficiency were further refined.
MCCI and pedestal damage assessment
Benchmark calculations using multiple severe accident codes provided new insights into molten core-concrete interaction (MCCI) phenomena. Comparative studies between simulation results and on-site observations — such as the survival of rebar and selective loss of concrete — have contributed to a more robust understanding of accident progression and structural response.
Cesium behavior in shield plug regions
Laboratory experiments using mock-up shield plug concrete gaps clarified the mechanisms of cesium deposition and re-entrainment under various thermal and flow conditions. The results are expected to inform future decontamination strategies and improve predictive deposition models.
International round robin activities
The meeting highlighted ongoing international round robin analyses, with research organisations comparing methodologies and results from examinations of common debris simulant samples. These efforts are laying the groundwork for future collaborative studies on actual debris samples.
Virtual experience: DebrisEye VR
During the meeting, participants also experienced a virtual tour of the Fukushima Daiichi Nuclear Power Station (FDNPS) using DebrisEye VR, developed by Japan Atomic Energy Agency (JAEA). This immersive experience allowed participants to explore the complex structures inside FDNPS and understand better the site’s current conditions, debris distribution, and work environment. The VR tour enabled deeper discussions and contributing to planning for future debris retrieval, decommissioning activities, and international collaboration.
Future outlook and challenges
- Preparations for the next FACE Project meeting in June 2026 (to be held in Fukushima);
- Designing the next phase (Post-FACE) to leverage project outcomes, strengthen international joint analyses, and promote expert exchange;
- Additional debris sampling and detailed analysis, advancement of aerosol behavior studies, supporting development of safe fuel debris retrieval operations;
- Enhancing safety and efficiency in decommissioning through closer integration of on-site insights and simulation tools.
Virtual tour of the Fukushima Daiichi Nuclear Power Station using DebrisEye VR
