Last update in March 2011
In 2005, IRSN launched a project concerned with the impact of extreme events on the transfers of materials. This project, entitles EXTREME, was in part born out of the results of the CAROL project, that enabled, on the scale of the lower Rhône valley, the determination of what had become of the various artificial radioactive element contributions that this region has been subjected to over the past forty years. The aim of EXTREME is to assess the impact of 'extraordinary' natural processes on the flow and distribution of radioactivity stocks, whether they are artificial or natural in nature.
Aims and issues
Although there has been a significant decrease in primary artificial radionuclide inflow into the environment over the last decade, significant secondary sources of radioactivity have accumulated over time. Redistribution phenomena, whereby these accumulated inventories are remobilised, today play a major role, particularly during intense meteorological events such as heavy precipitation or atmospheric deposition, flooding, storms, etc. Large masses of matter are liable to be displaced between locations during such episodes, leading to higher activity levels than those arising from average transfer processes, and producing radioactivity fluxes that can be equivalent to the fluxes accumulated over several months or even years.
This research focus is one of the striking scientific outcomes of the IRSN's CAROL project (CAmargue RhOne Languedoc), which ran until 2003. This project helped identify the major mechanisms leading to the current overall distribution of radionuclides within the Rhone catchment area, but also highlighted the gaps in current knowledge as to the consequences of extreme radionuclide redistribution processes. IRSN is involved in various national and international programs studying transfers during these exceptional phenomena, which make such large contribution to annual fluxes (regional project ORME, a European project EUROSTRATAFORM, PNEC).
The EXTREME project was launched by the Institute in 2005 to study the environmental impact and human consequences of natural processes that generate exceptional artificial natural radioactivity fluxes or inventories in various environments: the atmosphere, soils, rivers, coastal areas and deep sea environments. Results will be useful in developing responses to post-accident situations and for protecting the environment. In addition, the study will contribute to meeting society’s increasing demands for information on actual exposure at every level and on the consequences of exceptional meteorological events. The potential radiological consequences of these events on locally or temporarily affected populations can hence be assessed.
IRSN projects in support of the EXTREME project
Inter-regional CARMA project 2005-2007
The CARMA project (impact of alluvial deposits of the Rhone on the associated coastal environment: the case of extreme events) studies transfers from the coastal marine environment to the continental shelf of the Gulf of Lions during extreme weather and climate events. Launched in 2005 for a period of 48 months, the main goal of CARMA is to understand the dynamics of hydro-sedimentation in the area affected by Rhone River alluvia, and, in particular, the impact of high waters and storms on deep changes in the morphology of the coast and on what happens to fine particles that trap organic matter and contaminants, especially radionuclides.
Detailed description of CARMA project
EXTREMA project 2007-2010
The EXTREMA project, which is linked to research programs studying the impact of climate change, has the same objectives as the EXTREME project whilst extending the scope of investigation: firstly, to stable metal contaminants (Cu, Pb, Cd and Hg), and secondly to the Tet River and the Gulf of Lions as far as the submarine canyons at the edge of the continental shelf bordering the Mediterranean. EXTREMA includes a strong emphasis on modelling that will serve to predict the impact of global climate change on the redistribution of contaminant deposits in the Gulf of Lions for the next 20 to 30 years.
Detailed description of EXTREMA project
Theses and Post-docs
Continental aquatic environment
Marine aquatic environment