Overview of strontium-89,90 deposition measurements in Finland 1963-2005

摘要

In Finland the deposition of strontium-89 (~(90)Sr) and strontium-90 (~(90)Sr) has been monitored since the early 1960s. The measured cumulative ~(90)Sr deposition in 1963-2005 is on average 1200 Bq m~(-2), of which 150 Bq m~(-2) originates from the Chernobyl accident. Adding to this the deposition in 1945-1962 produces a value of 2040 Bq m~(-2) for the cumulative deposition in Finland. The nuclear explosion-derived deposition up to 1985 obtained in this study, 1850 Bq m~(-2), is in good agreement with the zonal ~(90)Sr deposition of 1740 Bq m~(-2) in the 60°N-70°N latitude band estimated by UNSCEAR. The regional deposition patterns of ~(89)Sr and ~(90)Sr following the Chernobyl accident resemble those of the refractory nuclides such as ~(239,240)Pu and ~(95)Zr. The total deposition of Chernobyl-derived ~(90)Sr in Finland was about 5.3 × 10~(13) Bq. This activity corresponds to 0.027% of the reactor core inventory and 0.66% of the atmospheric emissions from the accident. The corresponding figures for ~(89)Sr are 4.5 × 10~(14) Bq, 0.023% and 0.56%, respectively.