Americium and curium deposition in Finland from the Chernobyl accident

摘要

Am-241 and Cm-244 were analysed from peat samples collected in Finland immediately after the Chernobyl accident. The separation method included co-precipitation, anion exchange and extraction chromatography. Activities of Am-241 and Cm-244 were measured by alpha spectrometry. The activity of Chernobyl-derived Am-241 varied between 0.0115 and 9.32Bq/m(2) and that of Cm-244 from < 0.002 to 1.97 Bq/m(2) (reference date 1.5.1986). The origin of Am-241 in Finland is predominantly from atmospheric nuclear tests. However, the geographical distribution of Chernobyl-americium is uneven and depending on a location even 100% of Am-241 in peat originated from the Chernobyl accident. The deposition pattern of Chernobyl-derived Am-241 and Cm-244 resembles that of other refractory nuclides, such as Zr-95, Ce-141 and (239,240) Pu.