Carbon-14 (¹⁴C), the only naturally existing radioactive isotope of carbon, is of special interest for dose assessments related to releasesfrom the nuclear industry as it is the radionuclide that dominates the calculated dose to man.  For normal operation of nuclear power plants, liquid ¹⁴C effluents are significantly less than airborne releases. However, nuclear fuel reprocessing plants are known to release substantial amounts of liquid ¹⁴C. Other radionuclides originating from Sellafield reprocessing plant have e.g. been found in waters of the Swedish west coast.

One aim of this project is to investigate if this is also the case for ¹⁴C in the Swedish marine environment, and if Swedish coastal waters are affected by anthropogenic ¹⁴C sources. Another aim is to establish relevant marine background levels of ¹⁴C, which may vary spatially e.g. due to varying degrees of fresh-water river runoff and influence of long-range transport of anthropogenic ¹⁴C in the coastal waters. Samples of marine plants (e.g. Fucus when available) will be collected along the whole Swedish coast. In total at least 50 samples will be analysed for the content of ¹⁴C using Accelerator Mass Spectrometry (AMS) and of gamma emitting radionuclides. The data obtained in the project will be of great importance for correct dose assessment of ¹⁴C from the nuclear power industry.

The projected is funded by the Swedish Radiation Safety Authority SSM (SSM2019-5255).