Abstract

Nowadays, the development of nuclear energy is determined by solving the set of scientific and technical problems that provides reliable, safe and sustainable work of the operated and designed NPPs. At the same time different accident conditions and likelihood (probability) of variant equipment operating failures are analyzed. Obtained operating experience of the mixing low-pressure heaters (LPH) at thermal power plants (TPP) and NPPs shows that pulsations occur in some operation regimes of LPH turbine which lead to inner element destructions of LPH and pipeline malfunctions. These circumstances negatively affect operation of equipment that locates after LPH in condensate-supply tract. Consequently, unit capacity factor and economic indicators descend since troubleshooting for LPH mechanisms require some time and material resources. This work presents the experimental facility design and description of main design features of the facility components. The stand was designed to study the processes that lead to the vibration appearance in mixing LPH in condensate-supply tract of K-1000-60/3000 turbines. The main task of scale modeling is the need to observe equivalent conditions of the thermal-hydraulic processes behavior in the model in relation to full-scale equipment. To solve this problem using ANSYS code a preliminary simulation of hydraulic processes occurring in the experimental facility was performed. This allowed to determine in advance certain design features in the design of given facility. The results of experimental studies of the developed facility should allow to develop measures for reduction or complete elimination of vibrations in mixing LPH, as well as to validate computer programs for design analysis of stationary and non-stationary thermal-hydraulic processes in the specified equipment and designed measures testing.

Highlights

  • Obtained operating experience of the low-pressure heaters (LPH) at thermal power plants (TPP) and NPPs shows that pulsations occur in some operation regimes of mixing LPH-2 (MLPH-2) which lead to inner element destructions of LPH

  • As it was noted by the council of chemical experts from National Nuclear Energy Generating Company of Ukraine “Energoatom”, the electrical conductivity increase of steam generator (SG) blow-down water at the units No 3 and No 4 of the Rivne Nuclear Power Plant (RNPP) was due to elevated concentration of organic acids that are ethanolamine decomposition products

  • Prelaunch leak checks show impermeability of the mixing LPHs, considering that turbine power below 50 % leads to unstable operation of the mixing LPHs, which leads to vibrations

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Summary

Introduction

Obtained operating experience of the LPH at TPP and NPPs shows that pulsations occur in some operation regimes of mixing LPH-2 (MLPH-2) which lead to inner element destructions of LPH. The purpose of the work is to create a laboratory facility in compliance with the requirements on the thermal-hydraulic processes behavior of full-scale MLPH-2, which will allow to experimentally examine and identify areas of thermal-hydraulic instability that lead to the destruction of thermalhydraulic equipment elements of NPP and to develop recommendations for elimination of their negative effects and following testing on the specified facility. The heating steam from the inlet vapor volume passes under the lower plate where it partially condenses on the jets of water and carries off heat, enters the intermediate vapor volume, where it is rotated and directed to the jets of water of the upper plate. With the help of the pump (H2) cold water regulated by (CV4) and measured by a flow sensor (G3) is supplied to the heat exchanger (AT1) where it cools condensate that is supplied to the mixing heater inlet.

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Findings
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