Методический аппарат для разработки типовых сценариев развития запроектных аварий на АЭС с реакторами ВВЭР при планировании и проведении защитных мероприятий для населения

Abstract

To develop a simple methodological apparatus for constructing typical scenarios of accidents and estimate of emissions of radioactive substances from nuclear power plants with VVER reactors in the planning and implementation of protective measures for the population.Material and methods_ To build the model of release of radionuclides into the environment in case of an accident used literary experimental data of outputs of the radioactive substances from the fuel when it is heating and melting, the destruction of the fuel rod cladding, the use of technical means retention of radioactive substances in the containment of the reactor and their behaviour in the containment (sedimentation, sorption, etc.).Results_ Mathematical apparatus has been developed to quantify the magnitude of emissions of radioactive substances at nuclear power plants with VVER reactors depending on the time for dose-forming radionuclides in the instantaneous rupture of cooling pipelines in the presence of additional failure of NPP safety systems. The amount of emission of each deterministic of an accident correspond to the level 4 to 7 of the INES scale. Radionuclide release into the environment was calculated in the following physical and chemical processes_ heating and melting of fuel, depressurization of fuel rod claddings, peculiarities of the behavior of radionuclides in the containment shell (deposition, etc.) and operation of technical means to ensure radiation safety, structural leakages of the buildings. As an example, the assessment of the release of radionuclides into the environment depending on the time for level 5 of the INES accident scale is given. Conclusion_ Methodical apparatus can be used in the construction of typical scenarios for the development of basis accidents and assessment of radioactive emissions at nuclear power plants with VVER reactors in the planning and implementation of protective measures for the population and emergency exercises and training_