Sediment dating and sediment accumulation rate estimation using artificial radionuclides
Saarti, Leo Pietari (2026)
Julkaisun pysyvä osoite on
https://urn.fi/URN:NBN:fi:amk-202602042292
https://urn.fi/URN:NBN:fi:amk-202602042292
Tiivistelmä
Radiation and Nuclear safety authority (STUK) performs regular radioactivity surveillance in the surrounding areas near Loviisa nuclear powerplant. This study is used to calculate the sedimentation rate at the monitoring location LO2, near Loviisa nuclear power plant. This was done by using artificial radionuclides located in the sediment from historical nuclear fallout events.
Aim of this study is to measure the activity of artificial radionuclides of cesium-137 and americium-241 in sediment samples at different depths. This information is then used to calculate the sediment accumulation rate and to date the peaks in the activity profile to known radioactive fallout events.
Quantitative data was gathered through a gamma-spectrometer analysis and sediment sample measurements.
The results of this study show that the sediment accumulates at higher rate in the top layer (1.17 cm/year) and that for the purpose of monitoring local discharge of radioactive nuclides at the location of sampling it is not necessary to go beyond the depth of 3 cm. The average sediment accumulation rate at the monitoring location LO2 was 0.50 cm/year with Cs-137 calculations and 0.52 cm/year with Am-241 calculations. Each layer is approximately 2 years. Radioactive fallout from the Chernobyl powerplant accident was at a sample layer 19-20 cm. Am-241 activity peak was located in the sample layer 25-26 cm.
Aim of this study is to measure the activity of artificial radionuclides of cesium-137 and americium-241 in sediment samples at different depths. This information is then used to calculate the sediment accumulation rate and to date the peaks in the activity profile to known radioactive fallout events.
Quantitative data was gathered through a gamma-spectrometer analysis and sediment sample measurements.
The results of this study show that the sediment accumulates at higher rate in the top layer (1.17 cm/year) and that for the purpose of monitoring local discharge of radioactive nuclides at the location of sampling it is not necessary to go beyond the depth of 3 cm. The average sediment accumulation rate at the monitoring location LO2 was 0.50 cm/year with Cs-137 calculations and 0.52 cm/year with Am-241 calculations. Each layer is approximately 2 years. Radioactive fallout from the Chernobyl powerplant accident was at a sample layer 19-20 cm. Am-241 activity peak was located in the sample layer 25-26 cm.