The knowledge about environmental sensitivity of the marine regions to radionuclide release can be used for the development of response strategies and improvement of design-maker systems. The present results are based on the consequences analysis after potential Russian submarine accident involving a modern vessel. The radioecological consequences are based on modelling of potential releases of radionuclides, radionuclide transport and uptake in the marine environment. The sensitivity analysis is based on the comparison of the results of simulations with the recommendations and criterions for protection of the human population and the environment. The results show that the doses to marine organisms living in the sea sediment near the accident location, and dose rates to the critical group are the most sensitive state parameters (endpoints) for describing the consequences to the marine environment in the present evaluation.