In Russian project AES-2006 (NPP-2006), the overall safety concept for the nuclear power plant (NPP) is based on the in-depth defense principle, which implies the system of multiple barriers preventing the spread of ionizing radiation and radioactive substances into the environment. The last barrier preventing the release of fission products into the environment is the nuclear reactor building containment. During a severe accident like LOCA (Lost Of Coolant Accident), a large amount of hydrogen is produced in core reflooding and in oxidation of Zr fuel cladding by steam. When hydrogen appears inside the containment compartments, it mixes with steam and air thereby producing combustible mixture prone to detonation. In this paper, we present 3D simulation results of hydrogen-air-steam combustion in the NPP containment compartments using specialized 3D code FIRECON 1.0, with the complex geometry and a wide range of combustion regimes (from slow combustion to detonation) taken into account. Three scenarios are considered: (i) severe accident with break of pressurizer surge line accompanied by failure of active Emergency Core Cooling System (Large Break, LB LOCA); (ii) small leakage (Small Break, SB LOCA) from the cold loop thread with pressurizer failure, and (iii) uncontrolled severe accident (UnSA). The software is validated, and the dynamic loads imposed on the containment walls and inner structures are analyzed.

International Seminar on Fire and Explosion Hazards (9; 2019; Saint Petersburg, Russia). Proceedings of the Ninth International Seminar on Fire and Explosion Hazards [Электронный ресурс]: 21-26 April 2019, Saint Petersburg, Russia. Vol. 2 / Peter the Great St. Petersburg Polytechnic University, Autonomous Non-Profit Organization "Fire and Explosion Safety", Gefest Holding Ltd ; [edited by A. Snegirev [et al.]. — Электрон. текстовые дан. (1 файл : 98,7 Мб). — Saint Petersburg, 2019. — Загл. с титул. экрана. — Свободный доступ из сети Интернет (чтение, печать, копирование). — Adobe Acrobat Reader 7.0. — <URL:http://elib.spbstu.ru/dl/2/k19-97.pdf>. — <URL:http://doi.org/10.18720/SPBPU/2/k19-97>.