Atmospheric Emissions of Inert Radioactive Gases from Reactor and Radiochemical Production Facilities of the Federal State Unitary Enterprise Mayak PA and their Radiological Impact
Year: 2025
Type: article
Abstract: The paper considers the parameters of earlier existed (1948—2024) sources of inert radioactive gas (IRG) emissions associated with the Mayak’s reactor and radiochemical production facilities to support the establishment of scientifically based dose quotas for atmospheric krypton-85 ( 85Kr) emissions proposed for a new large radiochemical SNF reprocessing plant. The study evaluates the following parameters: radiation characteristics of all IRGs that could have been released into the atmosphere; the reconstructed IRG emissions; the calculated near-surface activity concentration and external radiation doses due to IRG emissions for the populated areas in the plant’s immediate vicinity; measured accumulated external radiation doses. The study shows that the calculated external radiation doses for the Ozersk residents in 1948—2024 provided their permanent exposure to the IRG emissions from the reactor production in the open area amount to (9—13) mSv, which seems to be in good agreement with the experimental data from direct measurements (1959—1989) and retrospective thermoluminescent dosimetry (1948—2006). As it comes to adult residents of the Ozersk city, it indicates that all through the operational life of the enterprise (1948—2024), the total effective dose of external exposure caused by 85Kr emitted from all stacks of the radiochemical and reactor production facilities did not exceed 1 μSv, which is ~100,000 times less than the annual threshold (1 mSv/year). The indicated doses can be estimated only based on relevant calculations, since they are much lower even than the radiation background fluctuations and cannot be measured using modern monitoring techniques. The following conceptual assumptions and approaches were proposed to be adopted in the designs of the new large radiochemical plant planned for construction at the existing site of FSUE Mayak PA: - provided the reprocessing capacity of 1,000 t/year of VVER-1000 SNF with a burnup of 40 GW/t and its cooling for 5 years, the 85Kr release into the atmosphere is assumed to amount to 3.1·1017 Bq/year and the annual external radiation dose for the Ozersk residents would not exceed 0.12 μSv/year; - an annual limit for 85Kr releases into the atmosphere of 0.6 μSv/year (provided a safety factor of 5) should be established; - there is no need to develop and install special systems to treat 85Kr releases from the discharge stack of the radiochemical plant.
Source: Radioactive waste
Authors: FSUE Mayak PA, Yu. G. Mokrov
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
Open Access status: bronze
OpenAlex ID: W4409338385