The issue of how to reduce radioactive releases following a reactor core meltdown was unfortunately brought to the fore by the Fukushima Daiichi accident. This issue is the focus of two international research programs, STEM and PASSAM.
The first program aims for a better understanding of the physicochemical behavior of fission products in the reactor containment; the second project, proposed by the Institute, seeks to acquire the knowledge needed to develop effective techniques to filter and trap the most toxic fission products.
Proposed by IRSN and co-funded by the European Commission, the new European project called Passive and Active Systems on Severe Accident source term Mitigation (PASSAM) aims to improve the filtration and trapping of fission products liable to be released into the environment during a core meltdown accident. The Institute is involved in the project with seven other partners (including EDF and Areva) from six EU Member States. This project will draw on the knowledge acquired by the Source Term Evaluation and Mitigation (STEM) project.
Initiated in 2011 under the auspices of the OECD, this four-year project will help improve understanding of the stability of fission products deposited outside the damaged reactor vessel and which, further on in the accident sequence, may be resuspended in the air and thus contribute to long-term releases in the environment. The first tests in the STEM project, which were conducted by IRSN, demonstrated a release under irradiation of volatile iodine species from particles deposited in the first few hours of the accident. These findings confirm the guidelines proposed by PASSAM to limit releases to the environment.
For more information:
Presentation of IRSN's research collaborations in Europe