Release of radioactive substances into the environment in severe accidents BN-1200M accidents: radiological protection according to international standards

«Radiation and Risk», 2026, vol. 35, No. 1, pp.5-17

DOI: 10.21870/0131-3878-2026-35-1-5-17

Authors

Ivanov V.K. – Scientific Advisor of NRER, Chief Radioecologist of Project “Proryv”, Chairman of RSCRP, Corresponding Member of RAS, D. Sc., Tech., Prof.
Menyajlo A.N. – Lead. Researcher, C. Sc., Biol.
Pryakhin E.A. – Researcher
Chekin S.Yu. – Head of Lab. A. Tsyb MRRC. Solomatin V.M. – Head of Dep. of the Chief Radioecologist, Project “Proryv”, C. Sc., Biol. JSC “Proryv”. Contacts: 4 Korolyov str., Obninsk, Kaluga region, Russia, 249035; e-mail: This email address is being protected from spambots. You need JavaScript enabled to view it. .
¹ Joint Stock Company “Proryv”, Moscow
² A. Tsyb MRRC, Obninsk

Abstract

The problem of radiological protection of the population and personnel in case of possible severe accidents of the BN-1200M reactor plant is considered. A reference level of radiation-induced carcinogenic risk of 10^-3 is used, corresponding to the reference level of 20 mSv for the population recommended by ICRP Publication 146 in 2020. The technology of modeling carcinogenic risk based on absorbed radiation doses in organs and tissues is used. The values of the expected effective doses were obtained when the carcinogenic risk of 10^-3 is reached for radionuclides Cs, I and Na, which make the main contribution to the radiation doses to the population in the event of a beyond design-basis accident of a power unit with a BN-1200M reactor plant. It has been shown that the radiotoxicity of the isotopes ²²Na and ²⁴Na increases by 2-3 times when they are inhaled, compared to oral intake, and the radiotoxicity of ¹³¹I is tens of times less than the radiotoxicity of radioisotopes Na and Cs. When implementing the principle of optimizing radiological protection in emergency exposure situations, it is necessary to consider that the reference levels, established in terms of radiation risk, ranging from moderate (10^-3) to significant (10^-2), can be achieved at significantly different effective doses, depending on the dose-forming radionuclide, the route of its entry into the human body, as well as depending on the sex and age of the exposed persons.

Key words
severe radiation accident, BN-1200M reactor plant, radionuclides, Cs, I, Na, expected effective dose, absorbed dose, reference dose level, reference risk level, medical examination, environmental health, public health.

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