Research Works on Iodine and Ruthenium Behavior in Severe Accident Conditions
Résumé
This paper deals with near past, ongoing, and planned R&D works on fission products(FPs) behavior in reactor cooling system (RCS), containment building and in filteredcontainment venting systems (FCVS) for severe accident (SA) conditions. All theresearches are collaborative works; the overall objective is to develop confident modelsto be implemented in simulation software. After being initiated in 2004, researches oniodine transport through the RCS are still ongoing and for containment, the last advancesare linked to the source term (ST) evaluation and mitigation (STEM) OECD/NEA project.The objective is to improve the evaluation of ST for a SA on a nuclear power plant and toreduce uncertainties on specific phenomena dealing with the chemistry of two major FPs:iodine and ruthenium. For ruthenium attention has been paid to study the amount andnature (gas/aerosol partition) of ruthenium species along the RCS. A follow-up, calledSTEM2, has started to reduce some remaining issues and be closer to reactor conditions.For FCVS works, the efficiencies for trapping iodine covering scrubbers and dry filtersare examined to get a clear view of their abilities in SA conditions. Another part isfocused on specific porous materials able to trap volatile iodine. Influence of zeolitematerials parameters (nature of the counter-ions, structure, Si/Al ratio...) are tested aswell as new kind of porous materials constituted by Metal organic Frameworks will alsobe looked at.