Wyniki wyszukiwania - BazTech

Ograniczanie wyników

Znaleziono wyników: 3

Liczba wyników na stronie

Wyniki wyszukiwania

Sortuj według:

Ogranicz wyniki do:

Use of an ejector to reduce the time of air injection during testing of the containment system at nuclear power plants

Surkov Sergii, Kravchenko Volodymyr, Korduba Iryna, Golovchenko Andrii, Butenko Oleksandr, Tsybytovskyi Serhii, Trach Yuliia

Przegląd Naukowy Inżynieria i Kształtowanie Środowiska

2024

Vol. 33, No. 4

401--418

The containment system (CS) is the last barrier to the release of radioactive substances into the environment in the event of a nuclear accident. After each overload, this system is tested for its ability to perform its functions by determining the integral leakage, which should not exceed a certain value. The tests are performed at an overpressure in the CS of 0.72 kgˑcm–2, which is achieved by injecting air with a compressor. The paper considers the use of an ejector to accelerate the injection process, which has a positive effect on the technical and economic performance of a nuclear power plant (NPP) power unit by increasing the amount of electricity generated, which is very important today, when the NPPs provide the maximum share of electricity generated in the country. Previous studies have evaluated the use of an ejector for this purpose, but they did not consider the need to install filters on the intake air stream. In addition, they used numerical methods that generate an error. The present work uses a mathematical apparatus that provides a more accurate result. The obtained calculated compressor injection time coincides with the actual injection time for the Rivne NPP power units. The design of the ejector ensures the minimum injection time is determined. The optimal ejector module is equal to 8.6 (the ratio of the cross-sectional area of the cylindrical mixing chamber to the critical cross-sectional area of the working air nozzle). This reduces the injection time by 38.8%. The suction air must be free of dust and moisture. Suitable filters have a total aerodynamic resistance of 0.2 bar. Taking these air filters into account slightly reduces the efficiency of the ejector. The final time of air injection using the ejector is 2.56 h, which reduces the time of air injection for testing by 35.5%.

Method of Analysis of Thermophysical Properties and Composition of Nuclear Fuel During Modernization of Active Zones of Nuclear Power Reactors

Vashchenko Volodymyr, Skalozubov Volodymyr, Korduba Iryna, Komarov Yuriy, Zhukova Olena

Ecological Engineering & Environmental Technology

2023

Vol. 24, iss. 6

186--191

The developed alternative method of analyzing the safety of the active zone of reactor installations is justified for improving the thermophysical properties and composition of nuclear fuel, designs of heat-releasing assemblies, reactor operation modes at increased or reduced power, etc. The impact of modernization on the safety criteria and conditions of reactor installations (RF) was analyzed. Attention was focused on the fact that until now there have been no sufficiently substantiated and accepted criteria and conditions for "steam" explosions in the Russian Federation. It was shown that when analyzing the safety of HF modernization with deterministic codes, it is necessary to take into account the possibility of negative effects of "user code" (EUC) and "code difference" (ECD), which can significantly affect the results of re-simulation of accidents with deterministic codes taking into account modernizations.

Determination of the Efficiency of Cooling Systems of Nuclear Power Plants of Ukraine in the Conditions of Global Climate Changes

Voloshkina Olena, Korduba Iryna, Zhukova Olena

Ecological Engineering & Environmental Technology

2023

Vol. 24, iss. 5

170--176

The impact of climate change on the efficiency of nuclear power plants and cooling reservoirs depends, to a certain extent, on the increase in the temperature of cooling reservoirs in the summer months of the year. Nuclear power plants use water throughout their lifetime in cooling systems to dissipate the waste heat generated, including system safety, cooling systems and for power generation. In this work, on the basis of the analysis of monitoring data, the correlation dependences between the temperature indicators of atmospheric air and cooling reservoirs for operating nuclear plants in the conditions of Ukraine are established. In order to obtain the efficiency of the operation of nuclear power plants depending on global climate changes, based on the analysis of the average monthly temperature indicators of the atmospheric air for the period 1881–2020, we made a climatic forecast of the atmospheric air for the territory of Ukraine and established the forecast dependence of the increase in air temperature for the period until 2160. Based on the assessment and forecasting of the influence of climatic factors on the temperature of the cooling water in the specified reservoirs and on the power of the stations, the values of the relative overall efficiency of the reactor at the NPP of Ukraine for the periods 2021–2030, 2031–2040 and 2041–2050 have been established. The obtained data, output power coefficients indicate a gradual decrease in output power in the next decades and in the Ukrainian nuclear energy sector in terms of operating nuclear power plants in the conditions of forecast values of global warming and cooling water temperature. They testify that climate change and global warming are a risk of emergency situations at nuclear power facilities, which requires making strategic decisions regarding adaptations of reactor operation in conditions of global climate change.