Rapportserie: Toktrapport ISSN:1503-6294 Publisert: 16.12.2019 Oppdatert: 01.03.2022
In July 2019, a research cruise to the wreck of the nuclear submarine “Komsomolets” was carried out with RV “G. O. Sars” and the advanced Remotely Operated Vehicle (ROV) Ægir 6000. The expedition was organised under the Joint Norwegian Russian Expert Group for investigation of radioactive contamination in Northern Areas. Using the ROV, the condition of “Komsomolets” was visually documented and samples of seawater, sediment and biota were taken at specific locations in the immediate vicinity of the submarine. Onboard analyses of seawater sampled directly from the ventilation pipe where releases have previously been documented, showed activity concentrations of 137Cs between <8.0 and 857 Bq/l. This indicates that releases from the reactor are still occurring, 30 years after “Komsomolets” sank. Based on our observations, the releases of 137Cs from “Komsomolets” to the marine environment appear to vary in amount and duration. Samples collected during the expedition will now be further analysed in the laboratory for 137Cs, 90Sr, Pu-isotopes and other radionuclides as well as trace metals to further understand the nature of the releases from the reactor and to determine if any plutonium from the two nuclear warheads has been released into the marine environment. The results will be compiled and published in a report under the Joint Norwegian Russian Expert Group by the end of 2020.