Seafood ingestion dose following the Fukushima accident using probabilistic and deterministic approaches

Mori, Airi; Johansen, M. P.*; Takahara, Shogo  

Radionuclides released from the Fukushima Daiichi Nuclear Power Plant (FDNPP) spread into the environment by various pathways, including the marine ecosystem and eventually into some marine organisms that could be consumed as seafood. Assessing this pathway is important from the perspective of public radiation protection. The ICRP presents two assessment methods (probabilistic and deterministic methods) for determining the dose for persons who are exposed to radiation. Which method to use and which specific values to select for each method depends on the characteristics of the assessment and available data, and it is left to the interpretation of the assessors. In this study, internal dose from seafood ingestion was assessed using an extensive compilation of activity concentrations in seafood that considers 22 radionuclides. The assessment receptor represents the residents in the Tohoku region which includes the Fukushima Prefecture. Representative consumption rates were obtained from a national nutritional survey. From the probabilistic calculation, the 95th percentile dose from the FDNPP accident-derived radionuclides was 22 Sv from seafood consumption during the first year after the accident and 1.6 Sv during the second and third year. Overall, the ingestion dose for typical seafood consumers of the Tohoku region returned to near background levels within 3 years. The differences in results between probabilistic and deterministic methods will be discussed in the presentation.