14C Entry into the Atmosphere

Abstract

¹⁴C enters the atmosphere in amounts equivalent to 1.4 PBq/yr with total accumulation 140 PBq via cosmic radiation. As a result of nuclear explosions (1950–1969), its activity in the atmosphere exceeded 200 PBq. At present, ¹⁴C has been completely removed into bottom waters and sedimentary rocks in the ocean. The activity of the ¹⁴C entering the atmosphere from all operating nuclear reactors equals ~0.3 PBq/yr and the amount from all spent fuel reprocessing facilities equals ~0.06 PBq/yr. The admissible levels of ¹⁴C emissions must not exceed levels corresponding to peroral intake dose 10 μSv/yr. This is can be accomplished by means of a system of measures: reduction of the volume of technogenic gases and their ¹²CO₂ content, combining high-efficiency purification with dispersion through high exhaust-stacks, and developing new technologies and reagents binding ¹⁴C in compact forms.