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The 14C emissions from NPP with RBMK-1000 and EGP-6 reactors as well as the yearly population irradiation dose due to these emissions are evaluated. A model is presented for calculating the population irradiation dose due to 14C emissions assuming an equilibrium 14C distribution between local food products and atmospheric air and absence of such an equilibrium for humans as a result of the consumption of imported food products. This model makes it possible to legitimately reduce the conservatism of the evaluation of the dose from standard NNP emissions as compared with the operating procedures and recommendations. The estimated population irradiation dose from 14C emissions is as follows, μSv/yr: 2.3 Smolensk, 1 Leningrad, 1.3 Kursk, and 0.034 Bilibino NPP. Irrespective of the computational model the 14C contribution in the total population irradiation dose due to emissions from NPP with RBMK-100 and EGP-6 reactors is significantly higher than 1%, so that it must be normalized and monitored. [ABSTRACT FROM AUTHOR]

Original data on radionuclide activities in air emissions of Russian NPPs are presented based on direct on-site measurements in vent stacks of NPPs during an extensive survey in 2017–2018. For the first time, the detailed inventories of radionuclides in the air releases were directly measured for all types of nuclear reactors, employed in the Russian NPPs. Based on the results of measurements, annual doses for local populations around the Russian NPPs were estimated. The technogenic radionuclides, detected in the air emissions, were ranked according to their contribution in the annual dose. 14C is the major contributor for the annual dose from the atmospheric releases of LWGR reactors – almost 98% for Bilibino NPP's EGP-6 reactor, and up to 86% for RBMK-1000 reactors (Smolensk NPP). For PWR reactors (VVER) contribution to the annual dose from atmospheric releases is formed mostly by tritium, 14C and noble gases. Estimated annual doses for local populations in the vicinity of the Russian NPPs do not exceed 10−5 Sv/year. Atmospheric releases of 60Co, 134Cs, 137Cs and other aerosols, involved in the routine monitoring programs of Russian NPPs, do not contribute significantly to the annual dose. Based on these results, 14C and tritium will be included in the monitoring programs of atmospheric release control at all Russian NPPs; maximal permissible levels of annual releases for 14C and tritium will be established since 2019. • Direct measurements of radionuclide emissions in vent stacks were performed for all Russian NPPs. • 14C, tritium and noble gases are among major contributors to doses from atmospheric releases. • Eleases of aerosols included to the current monitoring programs do not contribute significantly to the annual dose. • 14C and tritium will be included in the monitoring programs of atmospheric release control at all Russian NPPs since 2019. [ABSTRACT FROM AUTHOR]