REVIEW OF METHODIC INSTRUCTIONS AND RECOMMENDATIONS FOR EVALUATION OF ANNUAL EFFECTIVE DOSE TO HUMAN BEING IN CASES OF LIVING AT RADIOACTIVE CONTAMINATED AREAS

The proposed paper provides a review of recommendations, methodic instructions and software for evaluation of exposure doses to population domiciling radioactive contaminated territories. There is a review of dose calculation methods which are most common in neighbouring countries and beyond. The paper presents basic approaches, factors required for dose assessment with review of main pathways for artificial radionuclides intake. It addresses the need to develop methodic instructions and software for the cases of people living at Semipalatinsk test site area.

Discriminative Measurement of Absorbed Dose Rates in Air from Natural and Artificial Radionuclides in Namie Town, Fukushima Prefecture

Ten years have elapsed since the accident at the Fukushima Daiichi Nuclear Power Plant in 2011, and the relative contribution of natural radiation is increasing in Fukushima Prefecture due to the reduced dose of artificial radiation. In order to accurately determine the effective dose of exposure to artificial radiation, it is necessary to evaluate the effective dose of natural as well as artificial components. In this study, we measured the gamma-ray pulse-height distribution over the accessible area of Namie Town, Fukushima Prefecture, and evaluated the annual effective dose of external exposure by distinguishing between natural and artificial radionuclides. The estimated median (range) of absorbed dose rates in air from artificial radionuclides as of 1 April 2020, is 133 (67–511) nGy h−1 in the evacuation order cancellation zone, and 1306 (892–2081) nGy h−1 in the difficult-to-return zone. The median annual effective doses of external exposures from natural and artificial radionuclides were found to be 0.19 and 0.40 mSv in the evacuation order cancellation zone, and 0.25 and 3.9 mSv in the difficult-to-return zone. The latest annual effective dose of external exposure discriminated into natural and artificial radionuclides is expected to be utilized for radiation risk communication.

Accumulations of artificial radionuclides 137Cs and 239+240Pu in anchovy from the Korean seas

We investigated the accumulation patterns of the artificial radionuclides 137Cs and 239+240Pu in anchovy – categorized into four groups by size– from Korean seas. The activities of 137Cs and 239+240Pu were in the ranges of 74–137 mBq kg−1 and 0.27–3.21 mBq kg−1, respectively. They generally increased with increasing size (except for 239+240Pu in large anchovy), indicating radionuclide accumulation by seawater uptake through respiratory and/or higher feed capacity as a manifestation of growth. However, the activity of 239+240Pu decreased sharply in large anchovy. The calculated concentration factors (CFs) of 137Cs in anchovy were 10.9–20.2, which are an order of magnitude lower than those in other marine organisms. However, the CFs of 239+240Pu in adult anchovy were 14.0–162.8, which are significantly higher than those in other fishes and comparable (or even higher) to the IAEA recommendation values. The annual effective dose (AED) rates of 137Cs and 239+240Pu for anchovy consumption (per person) in South Korea were estimated to be 3.7 × 10−6–6.9 × 10−6 mSv yr−1 and 0.26 × 10−6–3.10 × 10−6 mSv yr−1, respectively. The AED from anchovy consumption is insignificant relative to that of natural radionuclides.