КЕРУВАННЯ АВАРІЯМИ З ПОВНОЮ ВТРАТОЮ ТРИВАЛОГО ЕЛЕКТРОПОСТАЧАННЯ НА ЯДЕРНИХ ЕНЕРГОУСТАНОВКАХ НАСОСАМИ З ПАРОПРИВОДОМ

• Date: 2020
• Main Authors: Skalozubov, V.I., Spinov, V.М., Luzhanskaya, А.V., Klimchuk, I.А., Gablaya, Т.V.
• Format: Article
• Language: English
• Published: V.M. Glushkov Institute of Cybernetics of NAS of Ukraine 2020
• Subjects: керування аваріями з повною втратою тривалого електропостачання; ядерні енергоустановки
• Online Access: https://jais.net.ua/index.php/files/article/view/490
• Journal Title: Problems of Control and Informatics

The accident with the complete loss of long-term power supply due to a tsunami flooding became the main cause of damage to nuclear fuel, devastating steam and gas explosions and catastrophic environmental consequences at the Fukushima-Daiichi nuclear power plant in 2011. After the Fukushima accident, the entire world nuclear community under the auspices of IAEA and the National Nuclear Safety Regulators came to the unequivocal conclusion about the necessity to improve emergency preventing measures and technical means to improve the management of accidents at nuclear power plants with complete loss of long-term power supply. One of such approaches to that problem solution refers to the development and implementation of an emergency feed pump steam-driven from the nuclear power plant steam generator, which does not require power supply and provides adequate duplication of the emergency feed pump design system. Elaborated are several methods of qualifying for reliability and operability the steam-driven emergency feed pump for management of accidents with a continued power supply full loss at nuclear power plants. The determining factor in qualifying the steam-driven emergency feed pump reliability refers to the cause, conditions and consequences of hydrodynamic shocks, accompanied by a pulsed high-amplitude increase in pressure and a sharp inhibition of flow energy. As a result of the design qualification of the steam-driven emergency feed pump reliability for controlling the accidents with complete loss of long-term power supply, it is established that the maximum amplitudes of hydraulic shock pressure never exceed 0,2 MPa. The hydraulic shock pressure maximum amplitudes reduction is possible due to the shortened launching time of the steam-driven emergency feed pump and the influence of the pump pressure-flow characteristic sensitivity parameters. At the issue of calculations and experimental qualification of the steam-sriven emergency feed pump operability at accident management when a complete loss of long-term power supply, it is established that the minimum allowable steam pressure in the steam generator is 0,18 MPa; and the time of reaching the operative (steady) regime is not less than 750 s. In this time interval, the relative power of residual heat is significant and never exceeds 70 %. Therefore, necessary is to substantiate alternative technical solutions for effective management of accidents with a complete loss of long-term power supply at the initial stage before the steam-driven pump reaches its operating (established) mode.