Модернізація стратегій і систем управління аваріями на ядерних енергоустановках з їх повним тривалим знеструмленням

• Дата: 2023
• Автори: Skalozubov, V., Kondratiuk, V., Pysmennyy, Ye., Komarov, Yu., Klevtsov, S.
• Формат: Стаття
• Мова: Ukrainian
• Опубліковано: State Scientific and Technical Center for Nuclear and Radiation Safety 2023
• Онлайн доступ: https://nuclear-journal.com/index.php/journal/article/view/1012
• Назва журналу: Nuclear and Radiation Safety

In today's extreme operating conditions of Ukrainian nuclear power plants (especially of the Zaporizhzhia NPP), as a result of external military influences, dozens of emergency shutdowns of power units occurred due to total or partial loss of external power supply. The long-term total blackout of nuclear power plants became one of the main causes for nuclear (severe) and radiation accidents with catastrophic environmental consequences at the Fukushima-1 NPP in 2011. The previously conducted deterministic analysis of a similar accident with a long-term blackout of VVER-1000 power units showed the inevitability of a nuclear accident under the conditions of exceeding the maximum permissible temperature of the nuclear fuel cladding. A promising approach to increase the management efficiency for NPP total blackout accidents is the use of an emergency feedwater pump with a steam drive from a steam generator. The necessary condition for implementing such an approach is qualification of the emergency feedwater steam driven pump for reliability and operability in total blackout accidents. The article justifies the qualification criteria and conditions for the emergency feedwater steam driven pump in transient and operating modes to ensure the successful performance of safety functions regarding the residual heat removal from the reactor and maintenance of the required feedwater level in the steam generator . On the basis of developed conservative thermal and hydrodynamic model “reactor – steam generator – emergency feedwater steam driven pump”, the structural and technical requirements for the system of an emergency feedwater steam driven pump are determined, which meet the established qualification criteria and conditions. It was determined, that the effective performance of the emergency feedwater steam driven pump from a steam generator is justified for the first 10 days after total blackout. The obtained results can be applied during the modernization of management strategies and systems for accidents with long-term total blackout of NPP units.