What kind of swamp will there be in Olkiluoto in the year 4000?
Researchers sought and found areas that could be similar to the swamps and lakes emerging in Olkiluoto. The purpose of the nature investigation is to find out how radioactive substances travel in the wild.
How can we investigate Olkiluoto’s future lakes and swamps as they do not yet exist? However, uplift means that they will emerge in the next few thousand years in the marine areas around Olkiluoto.
Posiva addressed this matter in a project launched in 2007 by using previous research data as the basis for finding 33 swamps and 27 lakes that were regarded as descriptive of the future conditions in Olkiluoto. Four swamps and seven lakes were selected from the data for further studies. The characteristics of them are the best match to the swamps and lakes that will emerge in Olkiluoto in the future.
“We improve the models of uplift and peat growth by means of research swamps and lakes. Based on the research, we prepare conveyance and dosage models of radioactive substances in case of a scenario where emissions would end up to the environment from the final disposal facilities. The research is related to the safety analysis of final disposal, and the data is needed for the operating permit application for the final disposal plant,” says Ari Ikonen, Posiva Team Lead in charge of biosphere evaluations.
Team lead Ari Ikonen is conducting biosphere research at Posiva
Maps indicate future conditions
In 2010, the mapping became field work related to the Lastensuo swamp in Eurajoki, Lake Koskeljärvi in Eura, Lake Lutanjärvi in Eurajoki, and also the Pesänsuo swamp in Loimaa in August 2011. The geology and vegetation of the swamps and lakes were mapped, the biomass volumes were measures along with taking samples of peat, plants and lakebeds.
The researchers took peat samples at a distance of a layer as thick as six metres. In laboratory testing, a radioactive signal substance will be added in the peat, and the level of radioactivity permeating the peat layer will be monitored.
“Radioactive substances bind well with the peat layer but start moving after changes such as draining,” says Ikonen.
He says that the swamps and lakes will be monitored for several years. According to Ikonen, it seems that one year per swamp will be enough for the research swamps, but the same lake will be monitored for several years due to the lack of vegetation growth models.
Posiva has prepared map models of the future conditions of Olkiluoto. Maps that indicate the situation as far as thousands and up to 10,000 years from now have been prepared on the basis of different scenarios. The evaluations account for the impact of sea level height, climate change and land use, for example.The swamp research has focused on the Lastensuo swamp in Eurajoki and the Pesänsuo swamp in Loimaa. Lasse Aro, Senior Researcher at the Finnish Forest Research Institute, takes a surface peat sample related to nature research in August 2010.
Posiva has prepared map models on the potential appearance of Olkiluoto in thousands of year after uplift. In this example, the map indicates new lakes, swamps and shoreline in about 2,000 years.